Caracterización bioinformática y producción de L-asparaginasa de Bacillus sp. M62 aislado de las salinas de Maras, Cusco, Perú

El objetivo del estudio fue realizar la caracterización bioinformática, así como optimizar la producción de L-asparaginasa extracelular de Bacillus sp. M62 aislada de las salinas de Maras (Cusco). Para ello, se verificó la producción de L-asparaginasa mediante el viraje del medio M9 modificado con azul de bromofenol 0.0075%, pH 7.4 a 37 °C por 72 h. A la vez, se extrajo el ADN genómico para amplificar los genes ribosómicos 16S y el gen ansA3. La secuencia aminoacídica codificada por el gen ansA3 se predijo mediante análisis bioinformático. La producción de L-asparaginasa intracelular y extracelular se evaluó a diferentes niveles de glucosa, L-asparagina, NaCl y pH en el medio M9 modificado. Adicionalmente, las actividades enzimáticas de L-asparaginasa y L-glutaminasa se determinaron mediante cuantificación del amonio liberado por el método de Nessler. Así, Bacillus sp. M62 produjo el viraje del medio M9 modificado, obtuvo alta similitud y cercanía evolutiva con Bacillus licheniformis, se encontró que el gen ansA3 amplificado codificaba para 319 aa, dentro de la cual se predijo una secuencia patrón del sitio activo (GFVITHGTDTM ) y 15 sitios inmunogénicos. La producción de L-asparaginasa extracelular fue superior a la intracelular, la que se optimizó de 0.37 U/mL (0.24 U/mg) a 2.15 ± 0.39 U/mL (0.63 U/mg). Finalmente, se encontró que Bacillus sp. M62 presenta L-asparaginasa extracelular con mínima actividad de L-glutaminasa.

The aim of this study was to perform bioinformatics characterization and optimize the production of extracellular L-asparaginase from Bacillus sp. M62, isolated from the Maras salt ponds (Cusco). To achieve this, the production of L-asparaginase was verified by the change in color of modified M9 medium, containing 0.0075% bromophenol blue, at pH 7.4 and 37°C for 72 hours. Genomic DNA was extracted to amplify the 16S ribosomal genes and the ansA3 gene. The amino acid sequence encoded by the ansA3 gene was predicted using bioinformatic analysis. The production of intracellular and extracellular L-asparaginase was evaluated at different levels of glucose, L-asparagine, NaCl, and pH in modified M9 medium. Additionally, the enzymatic activities of L-asparaginase and L-glutaminase were determined by quantifying the released ammonium using the Nessler method. Bacillus sp. M62 showed the change in color of the modified M9 medium, high similarity, and evolutionary closeness to Bacillus licheniformis. The amplified ansA3 gene was found to encode for 319 amino acids, with a predicted active site pattern (GFVITHGTDTM) and 15 immunogenic sites. The production of extracellular L-asparaginase was found to be higher than intracellular L-asparaginase and was optimized from 0.37 U/mL (0.24 U/mg) to 2.15 ± 0.39 U/mL (0.63 U/mg). Finally, it was found that Bacillus sp. M62 presents extracellular L-asparaginase with minimal L-glutaminase activity.

Efficient production of L-asparaginase in Bacillus licheniformis by optimizing expression elements and host / 生物工程学报

L-asparaginase (L-ASN) is widely applied in the treatment of malignant tumor and low-acrylamide food production, however, the low expression level hampers its application. Heterologous expression is an effective strategy to increase the expression level of target enzymes, and Bacillus is generally used as the host for efficient production of enzymes. In this study, the expression level of L-asparaginase in Bacillus was enhanced through optimization of expression element and host. Firstly, five signal peptides (SPSacC, SPAmyL, SPAprE, SPYwbN and SPWapA) were screened, among which SPSacC showed the best performance, reaching an activity of 157.61 U/mL. Subsequently, four strong promoters (P43, PykzA-P43, PUbay and PbacA) from Bacillus were screened, and tandem promoter PykzA-P43 showed the highest yield of L-asparaginase, which was 52.94% higher than that of control strain. Finally, three Bacillus expression hosts (B. licheniformis Δ0F3 and BL10, B. subtilis WB800) were investigated, and the maximum L-asparaginase activity, 438.3 U/mL, was reached by B. licheniformis BL10, which was an 81.83% increase compared with that of the control. This is also the highest level of L-asparaginase in shake flask reported to date. Taken together, this study constructed a B. licheniformis strain BL10/PykzA-P43-SPSacC-ansZ capable of efficiently producing L-asparaginase, which laid the foundation for industrial production of L-asparaginase.

Desenvolvimento e caracterização de lipossomas peguilados para veiculação de L-asparaginase / Development and characterization of peg-grafted liposomes for lasparaginase encapsulation

A Leucemia Linfoide Aguda (LLA) é um câncer de maior incidência em crianças, e tem a Lasparaginase (ASNase) como fármaco amplamente utilizado no tratamento dos afetados. A ASNase catalisa a hidrólise do aminoácido L-asparagina (Asn), presente na corrente sanguínea, a ausência do aminoácido no meio extracelular leva à morte células leucêmicas, que necessitam deste aminoácido para as funções celulares. Fatores envolvendo a eficiência do tratamento com ASNase como reações adversas e curta meia-vida, principalmente devido ao reconhecimento pelo sistema imune e degradação por proteases, limitam a sua eficácia. A encapsulação da enzima em lipossomas pode conferir proteção à degradação, melhorar seu perfil farmacocinético e diminuir os efeitos adversos, de forma a melhorar o tratamento da LLA sendo este o objetivo desse trabalho. Lipossomas de DOPC (1,2-dioleoil-sn-glicero-3-fosfocolina) e DMPC (1,2-dimiristoil-snglicero-3-fosfocolina) foram desenvolvidos empregando-se o método de hidratação do filme lipídico e diferentes protocolos de preparo contendo ou não diferentes concentrações de 18:0 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polietilenogicol)-2000] (DSPE-PEG). Os lipossomas produzidos foram utilizados para encapsular a ASNase e os sistemas contendo ou não ASNase encapsulada foram caracterizados por espalhamento de luz dinâmico (DLS), potencial zeta, microscopia eletrônica de transmissão (MET) e criomicroscopia de transmissão. Adicionalmente, foram avaliados a taxa de encapsulação e o perfil de permeabilidade das vesículas à L-asparagina. As análises de DLS mostraram que as nanoestruturas formadas empregando-se agitação magnética a partir de sistemas contendo 10% e 20% de DSPE-PEG possuem diâmetro hidrodinâmico menor (~ 25 nm a 60 nm) que os mesmos sistemas sem o fosfolipídio peguilado (~190 nm a 222 nm), demonstrando a relação entre a diminuição do tamanho e o aumento da quantidade de fosfolipídio peguilado e possível formação de estruturas micelares ou bicelares. O emprego de agitação em vórtex para hidratação do filme lipídico, adição do antioxidante -tocoferol e redução da concentração de DSPE-PEG (5% e 10%) levou à formação de sistemas com diâmetro hidrodinâmico maior, sendo esse protocolo e concentrações de PEG definidos como padrão. As análises de MET comprovaram a formação de lipossomas com diâmetro hidrodinâmico semelhante ao observado por DLS; com a utilização da criomicroscopia foi possível observar os lipossomas sem deformações. Os lipossomas de DMPC/DSPE-PEG 10% apresentaram maior permeabilidade à L-asparagina ao longo do tempo e, portanto, poderiam funcionar como nanoreatores, depletando o aminoácido da circulação. Estudos in vitro com células tumorais devem ser realizados e em seguida estudos in vivo, para confirmar este potencial

L-asparaginase (ASNase) is a first-choice drug, combined with other drugs, in therapeutic schemes to treat Acute Lymphoblastic Leukemia (ALL) in children and adolescents. ASNase catalyzes the hydrolysis of L-asparagine (Asn) in the bloodstream; since ALL cells cannot synthesize this amino acid, protein synthesis is impaired leading to leukemic cells death by apoptosis. In spite of its therapeutic importance, treatment with ASNase is associated to side effects, mainly hypersensitivity and immunogenicity. Another drawback refers to degradation by plasma proteases that altogether with immunogenicity shortens the enzyme half-life. Encapsulation of ASNase in liposomes, vesicular nanostructures formed by the self-aggregation of phospholipids, is an attractive alternative that possibly will protect the enzyme from plasma proteases, resulting on better pharmacokinetics profile. In this work, we prepared by thin film hydration liposomal formulations of the phospholipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or 1,2-dimyristoyl-sn-glycero-3- phosphocholine (DMPC) containing or not different concentrations of 18:0 1,2-distearoyl-snglycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG), and encapsulated ASNase by electroporation. The systems containing or not ASNase were analyzed by Dynamic Light Scattering, zeta potential and Electron Microscopy. The encapsulation efficiency and vesicles permeability were also evaluated. According to the DLS analysis, the nanostructures formed by film hydration under magnetic stirring employing 10% or 20% DSPE-PEG presented smaller hydrodynamic diameter (~ 25 nm to 60 nm) than the same systems without the pegylated phospholipid (~ 190 nm to 222 nm), demonstrating the relation between size and the amount of pegylated phospholipid that results in formation of micellar or bicellar structures. The protocol was stabilize by hydration of the lipid film under vortex agitation, addition of the antioxidant - tocopherol and reduction of the concentration of DSPE-PEG (5% and 10%), what altogether led to the formation of nanostructures of higher hydrodynamic diameter and monodisperse systems. TEM analyzes confirmed the formation of liposomes with hydrodynamic diameter similar to that observed by DLS; with the use of cryomicroscopy it was possible to observe the liposomes without deformations. Liposomes of DMPC/DSPE-PEG 10% showed permeability to L-asparagine over time and, therefore, could function as nanoreactors, depleting the circulating amino acid

Two-Step Purification of L-Asparaginase from Acrylaway® L

Abstract L-Asparaginase (L-ASNase) is a biopharmaceutical used for acute lymphoblastic leukaemia (ALL) treatment, dramatically increasing the patients' chance of cure. However, its production and distribution in developing countries were disrupted because of its low profitability, which caused great concern among patients. This study evaluates the feasibility of combining fractional precipitation and aqueous two-phase systems (ATPS) to purify L-ASNase from a low-grade product, commercially known as Acrylaway® L. The ATPS purification results were not particularly expressive compared to the two-step purification process composed of ethanol precipitation and gel filtration, which was able to recover the target molecule with a purification factor over 5 fold. Thus, we studied a purification process capable of manufacturing pharmaceutical grade L-ASNase from a commercially available low-grade raw material; however, improvements regarding its throughput must be achieved, and high purity is the first step to apply it as a new biopharmaceutical product. The proposed process could pose as a short-time solution to mitigate its shortage while a cost-effective production plant is being developed.

Pancreatitis aguda en niños con enfermedades hematooncológicas: aspectos clínicos y tratamiento / Acute pancreatitis in children with hemato-oncological diseases: clinical aspects and treatment

Resumen La pancreatitis aguda es una enfermedad inflamatoria del páncreas. Se observa con mayor frecuencia en niños bajo tratamiento por alguna enfermedad hematooncológica y se asocia principalmente con la administración de L-asparaginasa. Identificar esta complicación de forma temprana y establecer un plan terapéutico adecuado puede mejorar el pronóstico y reducir el riesgo de otras complicaciones. En este trabajo se realizó una revisión crítica de la literatura actual, con especial énfasis en los aspectos clínicos, el diagnóstico y el tratamiento de la pancreatitis aguda en niños con cáncer.

Abstract Acute pancreatitis is an inflammatory disease of the pancreas. It is currently seen more frequently in children undergoing treatment for a hemato-oncological disease and it is mainly associated with the administration of L-asparaginase. The early identification of this complication and the establishment of an appropriate therapeutic plan can improve its prognosis and reduce the risk of other complications. In this article, we make a critical review of the current literature, with special emphasis on the clinical aspects, diagnosis, and treatment of acute pancreatitis in children with cancer.

Análise Técnico-Econômica para a produção de biofármacos de L-asparaginase / Technical-Economic analysis for the production of L-asparaginase biopharmaceuticals

A enzima L-asparaginase é comumente utilizada como biofármaco para o tratamento da Leucemia Linfoblástica Aguda e possui altas taxas de cura com o medicamento disponível no mercado. Atualmente a aquisição deste biofármaco é fruto integral de importação, não sendo realizada produção nacional, muito embora existam grupos de pesquisas nacionais que trabalham em pesquisas e no desenvolvimento de biofármacos alternativos da L-asparaginase. Assim, a presente dissertação tem como objetivo realizar análises técnico-econômicas para avaliar a viabilidade de implementação industrial de bioprocessos para a produção da L-asparaginase do tipo Erwinase PEGuilada e não PEGuilada, que foram previamente desenvolvidos na FCF-USP. As análises técnico-econômicas foram conduzidas por meio do software SuperPro Design® (Intelligen, Inc.) e permitiram adaptar o processo laboratorial para um processo piloto e possibilitaram estimar os valores de custo de produção unitário (Unity Cost of Production - UPC) de US$ 12,37/mg e US$ 3,46/mg para a L-asparaginase monoPEGuilada e nativa obtida por processo similar, respectivamente. O custo unitário de produção para a enzima peguilada foi, portanto, estimado em cerca de 4 vezes o mesmo custo para a produção da enzima peguilada, sendo tal aumento de custo devido às operações de peguilação, já que ambas as plantas foram mantidas nas mesmas dimensões. Ainda, foram obtidos indicadores econômicos, que indicam a atratividade do processo desenvolvido, muito embora tenham sido identificados diversos gargalos de processo e fatores a serem otimizados e melhorados de forma a tornar o processo mais atrativo sob os pontos de vista técnico e econômico. Em uma análise de sensibilidade preliminar um aumento factível da densidade celular já mostra que é possível reduzir em mais de 30% o UPC. De toda forma, ainda que não otimizado, o processo apresentou valores e dados compatíveis com os biofármacos de L-asparaginase já disponíveis no mercado

The enzyme L-asparaginase is commonly used as a biopharmaceutical in the treatment of Acute Lymphoblastic Leukemia, presenting high cure rates with the formulations available on the market. Nowadays, the acquisition of this biopharmaceutical is only from importation, given that there is no national production being carried out, although there are national research groups working on research and development of alternative L-asparaginase biopharmaceuticals. Thus, this project aims at carrying out technical-economic analyzes to evaluate the viability of industrial implementation of bioprocesses for the production of L-asparaginase of the PEGylated and non-PEGylated Erwinase type previously developed at FCF-USP. The technical-economic analyzes, conducted by means of the software SuperPro Design® (Intelligen, Inc.), allowed to adapt the laboratory process to a pilot process and made it possible to estimate the unit cost of production (UPC) values of US $ 12.37 / mg and US $ 3.56 / mg for monoPEGylated L-asparaginase and bare obtained by similar process, respectively. The unit cost of production for the pegylated enzyme was, therefore, estimated at about 4 times the same cost for the production of the pegylated enzyme, such an increase in cost due to pegylation operations, since both plants were maintained in the same dimensions. Moreover, economic indicators were obtained, which indicate the attractiveness of the developed process. However, several process bottlenecks and factors to be optimized and improved were identified to make the process more attractive from the technical and economic point of view. In a preliminary sensitivity analysis, a feasible increase in cell density already shows that it is possible to reduce UPC by more than 30%. Accordingly, although not optimized, the process presented values and data compatible with the L-asparaginase biopharmaceuticals already available on the market

Estudo da estabilidade e peguilação de L-asparaginase em soluções aquosas de líquidos iônicos de imidazólio / Study of the stability and pegylation of L-asparaginase in aqueous imidazole ionic liquid solutions

A enzima L-asparaginase de Escherichia coli (ASNase) é um biofármaco indicado para o tratamento de leucemia linfoblástica aguda, mas que pode causar reações de hipersensibilidade nos pacientes tratados. Na tentativa de amenizar esse efeito, foi desenvolvida a PEG-ASNase (enzima conjugada com polietilenoglicol) que apresenta a vantagem de ser menos imunogênica e ter maior meia-vida biológica. Mais recentemente, novas abordagens têm sido desenvolvidas visando aprimorar os processos de PEGuilação por meio de reações sítio dirigidas, por exemplo N-terminal, a fim de promover maior similaridade lote a lote e controle das características farmacocinéticas e farmacodinâmicas do biofármaco. Porém, existe ainda uma limitação associada à hidrólise do PEG reativo, desta forma surge a necessidade de procurar solventes alternativos para a PEGuilação que permitam manter a estabilidade das proteínas, aumentar o rendimento de PEGuilação e a estabilidade do PEG reativo. Nesse trabalho, líquidos iônicos foram investigados como solventes alternativos para a peguilação N-terminal de PEG-ASNase. Para tal, a estabilidade de ASNase em Lis foi investigada em LIs da família metil-imidazol, analisando a influência do aumento da cadeia alquílica e de diferentes ânions. A estabilidade da ASNase é favorecida quando em contato com Lis relativamente hidrofóbicos ([C2mim]Cl, [C4mim]Cl e [C6mim]Cl), mas sua a atividade é prejudicada quando o LI é muito polar, como o [C4mim][(CH3)2PO4] ou anfifílico como o [C12mim]Cl. Apesar de seu efeito desnaturante, o [C4mim][(CH3)2PO4] resultou no maior rendimento da reação de PEGuilação da ASNase (56%) quando empregado a 75% e a reação realizada em 10 min. O [C4mim]Cl resultou em rendimento semelhante ao tampão fosfato (~ 49%), mas ambos os LIs reduziram a poliPEGuilação. Portanto, os Lis [C4mim]Cl e [C4mim][(CH3)2PO4] fornecem uma alternativa viável à reação de PEGuilação pela redução na formação de espécies poliPEGuiladas, o que facilitaria os processos de purificação e permitiria maior controle lote a lote da reação, bem como pelo aumento do rendimento da reação no caso do [C4mim][(CH3)2PO4]

Escherichia coli L-asparaginase enzyme (ASNase) is a biopharmaceutical indicated for the treatment of acute lymphoblastic leukemia, but may cause hypersensitivity in the patients used. In an attempt to alleviate this effect, PEG-ASNase (polyethylene glycol conjugated enzyme) was developed, which has the advantage of being less immunogenic and having a longer biological half-life. More recently, new approaches have been applied to improve PEGylation processes through targeted sites, for example N-terminal, in order to promote greater similarity to the batch and control of the pharmacokinetic and pharmacodynamic characteristics of the biopharmaceutical. However, there is still a limitation associated with reactive PEG hydrolysis, thus increasing the need to look for alternative PEGylation solvents to maintain protein stability, increase PEGylation yield and use reactive PEG. In this work, ions were investigated as alternative solvents for the N-terminal PEG-ASNase. For example, a stability of ASNase in ILs was investigated in imidazole ILs by analyzing the influence of increased alkyl chain and different anions. ASNase stability is enhanced when in contact with relatively hydrophobic ILs ([C2min]Cl, [C4min]Cl and [C6min]Cl), but its activity is impaired when very polar ILs such as [C4min][(CH3)2PO4] or amphiphilic as [C12mim]Cl. Despite its denaturing effect, [C4min][(CH3)2PO4] resulted in higher yield of ASNase PEGylation reaction (56%) when employed at 75% and reaction performed in 10 min. [C4min]Cl yielded similar phosphate buffer yield (~ 49%), but both ILs reduced polyPEGylation. Therefore, [C4min]Cl and [C4min][(CH3)2PO4] Ils may use a viable alternative to the PEGylation reaction and reduce the formation of polyPEGylated species, or that facilitate purification processes and allow for greater batch use of the solution, as well as increased reaction yield in the case of [C4min][(CH3)2PO4]

Mining and Evaluation of Post-marketing Safe Alert Signals of Pegaspargase and L-asparaginase Based on BCPNN Method / 中国药房

OBJECTIVE： To mine and evaluate the post-marketing safety alert signals of pegaspargase （PEG-ASP） and L-asparaginase （L-ASP），and compare the safety differences between them ，so as to provide reference for clinical safe and rational drug use. METHODS ： The adverse drug event （ADE） reports of PEG-ASP and L-ASP issued by FDA adverse event reporting system from Jan. 1st，2004-Jun. 30th，2020 were retrieved. BCPNN method was used to mine the safety signals of these two drugs under the condition that the lower limit of information component （IC－2SD）＞0 and the number of events ≥3. The medium and strong signals of two drugs with IC －2SD≥1.5 were evaluated and compared in 8 system organ class，such as gastrointestinal system ，hepatobiliary system ，blood and lymphatic system ，blood vessels and lymphatic vessels ， nervous system ，immune system ，metabolism and nutrition ，various examinations. IC value of specific ADE signal and its 95％ confidence interval were analyzed by time scanning spectrum. RESULTS & CONCLUSIONS ：The reports of PEG-ASP and L-ASP as suspected drugs were 2 324 and 3 824；67 and 68 medium and strong signals were included ，respectively. In gastrointestinal system，the common strong signal of PEG-ASP and L-ASP was necrotic pancreatitis. In hepatobiliary system ，both of them showed strong signal in venoocclusive liver disease ，and this ADE was not included in the drug instruction. In blood and lymphatic system ， common strong signals of the two drugs were febrile neutropenia ，coagulation disorder ，neutropenia and febrile bone marrow regeneration disorder ；in blood vessels and lymphatic vessels ，in addition to haemodynamic instability ，IC values of other signals of L-ASP were higher than those of PEG-ASP. In nervous system ，IC values of other signals of L-ASP were higher than those of PEG-ASP except for intracranial haemorrhage. In immune system ，anaphylactic reaction was a medium signal for L-ASP but was a strong signal for PEG-ASP. In metabolism and nutritional diseases ，except for tumor lysis syndrome ，IC values of other signals of L-ASP were higher than those of PEG-ASP. The results of time scanning spectrum showed that the signals of necrotic pancreatitis and coagulation disorder of PEG-ASP were stable ，while the signals of veno occlusive liver disease and hypersensitivity were unstable and needed to be observed ；above four signals of L-ASP were stable signals. When using PEG-ASP or L-ASP clinically ， close attention should be paid to the safety problems such as hypersensitivity ，coagulation disorder ，thrombosis，necrotic pancreatitis，venoocclusive liver disease and hypoproteinemia.

Molecular modification and highly efficient expression of L-asparaginase from Rhizomucor miehei / 生物工程学报

L-asparaginase hydrolyzes L-asparagine to produce L-aspartic acid and ammonia. It is widely distributed in microorganisms, plants and serum of some rodents, and has important applications in the pharmaceutical and food industries. However, the poor thermal stability, low catalytic efficiency and low yield hampered the further application of L-asparaginase. In this paper, rational design and 5' untranslated region (5'UTR) design strategies were used to increase the specific enzyme activity and protein expression of L-asparaginase derived from Rhizomucor miehei (RmAsnase). The results showed that among the six mutants constructed through homology modeling combined with sequence alignment, the specific enzyme activity of the mutant A344E was 1.5 times higher than the wild type. Subsequently, a food-safe strain Bacillus subtilis 168/pMA5-A344E was constructed, and the UTR strategy was used for the construction of recombinant strain B. subtilis 168/pMA5 UTR-A344E. The enzyme activity of B. subtilis 168/pMA5 UTR-A344E was 7.2 times higher than that of B. subtilis 168/pMA5-A344E. The recombinant strain B. subtilis 168/pMA5 UTR-A344E was scaled up in 5 L fermenter, and the final yield of L-asparaginase was 489.1 U/mL, showing great potential for industrial application.

Modeling and validation of L-asparaginase enzyme, an anticancer agent using the tools of computational biology

Background: The L-Asparaginase is a medically important drug. The L-Asparaginase enzyme, an anticancer agent produced by microorganisms is used for the treatment of patients suffering from lymphoma and leukemia. The L-Asparaginase is economical and its administration is easy when compared to other commercial drugs available in market. Many microbes have been reported to produce the L-Asparaginase.Methods: In the present work the sequence of L-Asparaginase enzyme protein was obtained from the Universal Protein Resource (UNIPROT) server. The sequence of L-Asparaginase was used to generate 3-D model of L-Asparaginase in SWISS MODEL server. The constructed L-Asparaginase model was verified using Ramachandran Plot in PROCHECK server.Results: The FASTA format of L-Asparaginase enzyme of Bacillus subtilis strain 168 was retrieved from UNIPROT server. The FASTA format of L-Asparaginase was submitted to SWISS MODEL and its three-dimensional structural model was developed based on relevant template model. The model structure of L-Asparaginase was validated in PROCHECK server using Ramachandran Plot. The Ramachandran Plot of L-Asparaginase model inferred the reliability of L-Asparaginase structure model developed in SWISS MODEL server.  Conclusions: In the present study computational tools were exploited to develop and validate a potent anticancer drug, L-Asparaginase. Further the modeled L-Asparaginase enzyme protein can be improved using advanced bioinformatics tools and the same improved enzyme can be produced by improving the L-Asparaginase producing microbial strains by site-directed mutagenesis in the corresponding gene.

L-asparaginase de Erwinia chrysanthemi: expressão proteica livre de células e bioconjugação a bacteriófagos / L-asparaginase from Erwinia chrysanthemi: cell-free protein expression and bioconjugation to bacteriophages

A L-Asparaginase (L-ASNase) de Erwinia chrysathemi (ErA) é uma enzima amplamente utilizada para o tratamento da leucemia linfoblástica aguda (LLA). Embora o seu uso como segunda linha de tratamento para a LLA tenha proporcionado consideráveis benefícios clínicos, reações de hipersensibilidade e rápida depuração plasmática ainda são problemas recorrentes. Ademais, extensivos e custosos processos de produção da ErA são necessários para a obtenção da enzima pura. Com base nesses problemas, o presente trabalho propõe (1) o estudo de viabilidade de expressão da ErA em um sistema de síntese proteica livre de células (SPLC) e (2) a conjugação da proteína em bacteriófagos como ferramenta alternativa para o isolamento e monitoramento da depuração plasmática da ErA. Foram utilizados extratos celulares de Escherichia coli suplementados com solução energética contendo creatina fosfato (CP) como fonte de energia para síntese in vitro de ErA. Para conjugação da ErA a bacteriófagos, o sistema SpyTag/SpyCatcher foi implementado: SpyCatcher foi fusionado à porção N-terminal da ErA e bacteriófagos filamentosos da linhagem M13 e fd foram modificados de modo a expressar SpyTag nas proteínas de capsídeo pIII e pVIII, respectivamente. Em relação ao primeiro objetivo, o sistema de SPLC foi capaz de expressar a ErA com atividade. A proteína foi expressa na fração solúvel e apresentou atividade enzimática significativamente superior em relação à reação controle (7,07 ± 0,68 U/mL vs. 1,83 ± 0,14 U/mL). Tempo necessário para obtenção do extrato celular foi reduzido de 45 para 26 hrs, e sete componentes da solução energética foram removidos da composição original sem implicações negativas na eficiência de expressão da ErA, simplificando desta forma o processo de SPLC. Em relação ao segundo objetivo, ErA fusionada à SpyCatcher (SpyCatcher_ErA) foi conjugada com êxito em bacteriófagos capazes de expressar SpyTag fusionadas na porção N-terminal das proteínas pIII (SpyTag_pIII) e pVIII (SpyTag_pVIII). A porcentagem de formação dos conjugados entre SpyCatcher_ErA e SpyTag_pIII ((ErA)5-pIII) foi de 6% enquanto formação dos conjugados entre SpyCatcher_ErA e SpyTag_pVIII ((ErA)50-pVIII) foi de 46%, valores estes confirmados por atividade enzimática. Solução contendo conjugados foram injetados em camundongos e sequenciados/titulados com êxito. Não houve diferença de depuração plasmática entre (ErA)5-pIII e bacteriófago controle, mas houve maior taxa de eliminação de (ErA)50-pVIII em relação ao mesmo bacteriófago não conjugado à SpyCatcher_ErA. Os resultados aqui apresentados confirmam ser possível expressar ErA com atividade biológica em sistemas de SPLC. Além disso, o sistema de conjugação da ErA a bacteriófagos aqui desenvolvido foi capaz de monitorar a concentração de ErA presente na circulação em função do tempo, tornando-se uma potencial plataforma de desenvolvimento de novas proteoformas da ErA com características clínicas melhoradas

L-Asparaginase (L-ASNase) from Erwinia chrysanthemi (ErA) is a widely used enzyme for treatment of acute lymphoblastic leukemia (ALL). Although its use as a second-line treatment has provided significant clinical benefits, hypersensitivity reactions and a fast clearance rate are recurring L-ASNase-related problems. In addition, extensive and costly production processes are required for the manufacturing of pure ErA. Based on these drawbacks, this current work proposes (1) the study of the use of a cell-free protein synthesis (CFPS) system as a viable platform for the synthesis of ErA and (2) the conjugation of the protein on bacteriophages as an alternative tool for the isolation and monitoring of ErA clearance. Escherichia coli-derived cell extracts supplemented with a creatine phosphate-based energy solution were used to synthesize ErA in vitro. To conjugate ErA on bacteriophages, the SpyTag/SpyCatcher system was implemented: SpyCatcher was fused to the N-terminus of the ErA while filamentous phage strains M13 and fd were engineered in order to display SpyTag on their pIII and pVIII capsid proteins, respectively. Regarding the first goal, the CFPS system was able to express an active ErA. The protein was expressed in the soluble fraction and there presented a significant higher enzymatic activity compared to the control reaction (7.07 ± 0.68 U/mL vs. 1.83 ± 0.14 U/mL). Time required to obtain the cell extract was reduced from 45 to 26 hours, and seven energy solution reagents were removed from the original solution without compromising the efficiency of ErA expression, thus simplifying the CFPS process. With respect to the second goal, ErA fused to SpyCatcher (SpyCatcher_ErA) was sucessfully conjugated on bacteriophages capable of displaying SpyTag fused to the Nterminus of the pIII (SpyTag_pIII) or pVIII (SpyTag_pVIII) proteins. Percentage of conjugate formation between SpyCatcher_ErA and SpyTag_pIII (ErA)5-pIII was 6% whereas conjugate formation between SpyCatcher_ErA and SpyTag_pVIII (ErA)50-pVIII was 46%, values that were confirmed by enzymatic activity. Sample containing conjugates were injected into mice and sucessfully sequenced/titrated. No clearance differences were observed between (ErA)5- pIII and a control bacteriophage, but a higher clearance rate was observed for (ErA)50-pVIII compared to SpyTag_VIII non conjugated to SpyCatcher_ErA. The results here presented confirm the expression of a biologically active ErA from a CFPS system. Besides, the development of a conjugation system capable of linking ErA to bacteriophages could be used as a means to monitor the ErA concentration in the blood as a function of time and also as a potential platform to be used in the development of novel ErA proteoforms with improved clinical properties

Production of L-asparaginase by Aspergillus niveus under solid-state fermentation using agroindustrial byproducts

Background:L-asparaginase, produced mainly by microrganisms, cleaves L-asparagine to aspartic acid and ammonia as products. This enzyme has been applied in the treatment of the leukemia and in food preparation preventing the acrylamide formation. Methods:Aspergillus niveuswas grown in different solid substrates (agroindustrial byproducts) moistened with different agents (tap water, distilled water and several salt solutions) for different periods (24-240 h) at 30ºC. The enzyme extract was obtained with the addition of cold distilled water, agitation at 50 rpm for 30 min and filtration. The filtrate was used to determine the L-asparaginase activity through the hydroximate aspartic methodology using L-asparagine as substrate. The influence of temperature (30-75ºC), pH (3-9) and chemical compounds on the enzyme activity was analyzed.Results:The highest level of enzyme production was obtained using the M1 mixture (wheat bran, crushed soybean, orange peel; 1:1:1, w/w/w) as substrate humidified with Czapeck Dox salt solution (1:0.5, m/v) for 48-120 h, at 30ºC. The best temperature and pH for the enzyme activity were 35ºC and 5.0, respectively. The enzyme activity was increased in the presence of NaCl and some organic solvents (acetonitrile, butanol ethanol, isopropanol and methanol).Conclusions:A. niveusproduced L-asparaginase under SSF using a mixture of agroindustrial byproducts as solid substrate in the absence of L-asparagine as inducer. The temperature and pH of activity,as well as the NaCl tolerance, indicate its potential to be applied for different purposes. A. niveuscan be an interesting source of L-asparaginase gene to be investigated targeting future application.

Reacciones alérgicas por L-asparaginasa en niños con leucemia linfoide aguda / L-asparagibase allergic reactions in children with lymphoblastic acute leukemia

La L-asparaginasa es un medicamento utilizado en distintas fases de todos los protocolos de tratamiento actuales de la leucemia linfoide aguda (LLA). Se describen múltiples manifestaciones secundarias a la L asparaginasa entre las que las reacciones alérgicas son las más frecuente. Se estudiaron 144 niños con diagnóstico de LLA tratados en el Instituto de Hematología e Inmunología, entre 1998 y el 2013. En 30 pacientes (21 por ciento) se presentaron reacciones alérgicas, similar a lo descrito en la literatura. El 76,6 por ciento de ellos habían recibido una dosis acumulativa menor de 80 000 UI (media de 48 757) y el mayor número de las reacciones alérgicas (86,7 por ciento) se reportó entre las dosis 9 y 18 recibidas (media de 11 dosis). Se observó una mayor supervivencia en los enfermos que recibieron más dosis (19 - 26 dosis) (p = 0.003). La sobrevida libre de eventos fue también mayor en este grupo (p= 0.357)(AU)

ABSTRACT L-asparaginase is a medication used in different phases of all current treatment protocols for acute lymphoid leukemia. Multiple secondary manifestations to L- asparaginase are described, and allergic reactions are the most frequent. We studied 144 children with acute lymphoblastic leukemia treated at the Instituto de Hematología e Inmunología between 1998 and 2013. Thirty patients (21 percent) had allergic reactions, similar to what is described in literature; 76.6 percent of them had received a cumulative dose of less than 80 000 IU (average of 48 757); and the highest number of allergic reactions (86.7 percent) was reported between doses 9 and 18 received (mean of 11 doses). A greater global survival was observed in patients who received more doses (19 - 26 doses) (p=0.003). Event free survival was also higher in this group (p= 0.357)(AU)

Produção de L-asparaginase pela levedura Leucosporidium muscorum CRM 1648 isolada de sedimento marinho coletado na Península Antártica / L-asparaginase production by the yeast Leucosporidium muscorum CRM 1648 isolated from marine sediments collected in Antarctic Peninsula

L-asparaginase (L-ASNase) é uma enzima com propriedades interessantes para a indústria médica, farmacêutica e de alimentos, que tem recebido atenção especial, inclusive no Brasil, por fazer parte do protocolo de tratamento de distúrbios linfoproliferativos, como a leucemia linfoblástica aguda (LLA). No mercado desde a década de 1970, as enzimas de origem bacteriana enfrentam algumas limitações por provocarem reações adversas graves em quase 80% dos pacientes em tratamento. Nesse contexto, L-ASNases provenientes de leveduras se destacam como alternativa, por serem mais próximas às congêneres humanas. A Antártica ainda é um ambiente pouco explorado, com grande diversidade de microrganismos com potencial para a produção de moléculas biológicas de interesse industrial. Nesse contexto, 150 leveduras isoladas de amostras de sedimento marinho coletadas na Península Antártica como parte do projeto MICROSFERA (PROANTAR/CNPq) foram avaliadas para a produção de L-ASNase. A triagem resultou em 9 isolados produtores, dos quais 7 pertencem ao gênero Leucosporidium. A linhagem L. muscorum CRM 1648 foi a que produziu mais enzima (540 U.L-1), com maior produtividade (5,6 U.L-1.h-1) e, por isso, foi alvo deste estudo. A análise univariada de fontes de carbono e nitrogênio indicou maior crescimento desse microrganismo e produção de L-ASNase em meio CD com extrato de levedura, prolina e sacarose. Ureia, cloreto de amônio e sulfato de amônio resultaram em baixa ou nenhuma produção da enzima, sugerindo que a metabolização de fontes de nitrogênio por essa linhagem está sob a influência do fenômeno de repressão catabólica pelo nitrogênio (RCN). Dois delineamentos experimentais do tipo fatorial completo resultaram em um aumento de 10 vezes na produção e produtividade da enzima (4582,5 U.L-1 e 63,6 U.L-1.h-1, respectivamente). A análise univariada da concentração inicial de inóculo (X0), pH inicial do meio, temperatura e adição de água do mar mostrou que a melhor condição para a produção foi: pH = 5,5 ou 6,5, cultivo a 15°C com adição de água do mar (25-50% m/v). A variável X0 não foi significativa nas concentrações avaliadas. Cultivos em biorreator (batelada) foram conduzidos em quatro diferentes níveis de oxigênio dissolvido (OD): (1) OD não controlado e abaixo de 20%, (2) OD não controlado e acima de 20%, (3) OD controlado em 80% e (4) OD controlado em 20%. Os resultados mostraram que OD é fator limitante para o crescimento de L. muscorum CRM 1648 e produção de L-ASNase por essa levedura e deve ser mantido acima de 35% para maior produção da enzima.Neste trabalho, a composição do meio e condições de cultivo foram estabelecidas para favorecer a produção de uma nova L-ASNase livre de atividade glutaminásica por levedura adaptada ao frio, abrindo espaço para novos estudos acerca de seu potencial antileucêmico e possível uso como alternativa às enzimas já existentes no mercado no tratamento de LLA

L-asparaginase (L-ASNase) is an enzyme with interesting properties for medical, pharmaceutical and food industry, which has received special consideration, especially in Brazil, for being part of lymphoproliferative disorders treatment, such as acute lymphoblastic leukemia (ALL). Bacterial enzymes are on the market since the 1970s and face some limitations related to theirserious adverse reactions that reach almost 80% of all patients in treatment. In this context, L-ASNases from yeasts are highlighted as important alternative to bacterial enzymes, due to the closerphylogeny to human congeners. Antarctic environment has much to be explored, with a vast diversity of microorganisms with potential to produce biomolecules with industrial interest. A total of 150 yeasts isolated from Antarctic marine sediments as part of MICROSFERA project (PROANTAR/CNPq) were evaluated for L-ASNase production. The screening resulted in 9 producers, 7 species from the genus Leucosporidium. L. muscorum CRM 1648 was the strain that yielded the highest L-ASNase activity (540 U.L-1) and volumetric productivity (5.6 U.L-1.h-1). Carbon and Nitrogen sources were evaluated by a method of one-factor at a time (OFAT). From the gather results, sucrose, yeast extract and proline resulted in a maximal growth and highest enzyme production.The absence or low production of L-ASNase in medium with urea, ammonium chloride and ammonium sulfate suggests the presence of nitrogen catabolic repression (NCR). Carbon and nitrogen concentration were evaluated by full factorial design and yielded about ten times higher enzyme and volumetric productivity (4582.5 U.L-1 and 63.6 U.L-1.h-1, respectively). Initial inoculum concentration (X0), initial pH, temperature and concentration of seawater in the culture were evaluated by OFAT analysis and the best condition for L-ASNase production was: pH = 5.5 or 6.5, at 15 °C with addition of seawater (25-50 wt%). X0 was not considered a significant variable. Bioreactor assays (in batch regime) were performed in four different dissolved oxygen (DO) levels: (1) without DO control (DO remained under 20%), (2) without DO control (DO remained above 20%), (3) DO controlled at 80%, and (4) DO controlled at 20%.The results showed that DO is a key factor for growth of L. muscorum CRM 1648 and production of L-ASNase by this yeast and should be maintained above 35% for higher production of this enzyme.At this work, the medium and culture conditions were established to support the production of a novel glutaminase-free L-ASNase by a cold adapted yeast, opening a new path for further studies regarding its antileukemic potential and possible use as an alternative for ALL treatment

Pancreatitis aguda como efecto adverso de L-asparginasa en el tratamiento de la leucemia linfocítica aguda / Acute pancreatitis as an adverse side effect of L-asparaginase in the treatment of acute lymphoblastic leukemia

Resumen La leucemia linfocítica aguda es la enfermedad oncológica con mayor incidencia en la población pediátrica, tanto a nivel mundial como en Costa Rica. Para su tratamiento requiere protocolos de quimioterapia complejos, lo que representa un reto constante para los médicos, ya que deben equilibrar los riesgos y beneficios del manejo. Es necesario tomar en cuenta los factores de riesgo de cada paciente, el grado de severidad de la enfermedad y los potenciales efectos adversos del tratamiento. A continuación, se reporta un caso de pancreatitis aguda edematosa no biliar, secundaria al uso de L-asparginasa, en un paciente con diagnóstico de leucemia linfocítica aguda, atendido en el Hospital Nacional de Niños "Dr. Carlos Sáenz Herrera". El paciente, quien se encontraba cumpliendo el régimen poliquimioterapeútico AHOPCA 2008, presentó clínica sugestiva de pancreatitis aguda en el día 50 de este, por lo que se decidió no colocar la quimioterapia indicada e inmediatamente se trasladó al Servicio de Emergencias. El cuadro clínico estaba asociado a laboratorios y ultrasonido anormales, por lo que fue tratado interdisciplinariamente y su pronóstico fue favorable; actualmente continúa con tratamiendo quimioterapeútico, como fue indicado.

Abstract The acute lymphocytic leukemia is the oncological disease with the highest incidence in the pediatric population both worldwide and in Costa Rica. It requires complex chemotherapy protocols, which confers a constant challenge on physicians to balance the risks and benefits of management. Therefore, it is necessary to take into account the risk factors of each patient, the degree of severity of the disease and the potential adverse effects of the treatment. A case report is presented with an acute non-biliary edematous pancreatitis, secondary to the use of L-asparaginase in a patient diagnosed with acute lymphocytic leukemia, seen at the National Children's Hospital "Dr. Carlos Sáenz Herrera". The patient who was started on the AHOPCA 2008 polychemotherapy regimen presented symptoms suggestive of acute pancreatitis on the day 50 of the same, so it was decided not to apply the indicated chemotherapy and transfer the patient to the Emergency Room. The clinical picture was associated with abnormal laboratories and ultrasound, so it was immediately treated interdisciplinarily, which is why its prognosis was favorable and currently he continues with chemotherapy treatment as indicated.

Effectiveness of L-asparaginase-based regimens compared to anthracycline-based regimens in newly diagnosed extranodal NK/T-cell lymphoma, nasal type: a single Mexican center experience

BACKGROUND: Extranodal NK/T-cell lymphoma, nasal type (ENKTCL) has a high prevalence in Asia and Latin American countries, such as Mexico, where it encompasses 40% of all T-cell non-Hodgkin lymphomas. Historically, responses to anthracycline-based therapies have been disappointing. Since data about the effectiveness of L-asparaginase-based regimens in Mexico are limited, we compared both therapies in our center. METHODS: We performed a retrospective cohort of patients with newly diagnosed ENKTCL, who were divided into two groups for treatment and analysis (group 1: L-asparaginase-based regimen and group 2: anthracycline-based regimen) between 2001 and 2016. RESULTS: Of 36 patients with newly-diagnosed ENKTCL, 33 received at least one cycle of chemotherapy (22 in group 1 and 11 in group 2). Over a median follow-up interval of 17 months (range, 0–167), a complete response (CR) was observed in 45.5% of patients in group 1, compared to 27% of group 2 (P=0.45). Progression was more frequently observed in group 2 than in group 1 (54.5% vs. 18.4%, P=0.04). The median overall survival (OS) was 44 months in group 1, compared to 5 months in group 2 (P=0.012). The multivariate analysis showed that failure to achieve a CR after first-line therapy was the only significant factor for OS (HR, 3.04; 95% CI, 1.4–6.5; P=0.005). CONCLUSION: L-asparaginase-based regimens for patients with newly-diagnosed ENKTCL confer a survival advantage over anthracycline-based regimens.

Comparison of Native Escherichia coli L-Asparaginase versus Pegylated Asparaginase, in Combination with Ifosfamide, Methotrexate, Etoposide, and Prednisolone, in Extranodal NK/T-Cell Lymphoma, Nasal Type / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The aim of this study was to compare asparaginase-related toxicities in two asparaginase preparations, namely native Escherichia coli L-asparaginase (L-ASP) and pegylated asparaginase (PEG-ASP) in combination with ifosfamide, methotrexate, etoposide, and prednisolone (IMEP) in natural killer (NK)/T-cell lymphoma (NTCL). MATERIALS AND METHODS: A total of 41 NTCL patients who received IMEP plus native E. coli L-ASP or PEG-ASP at Seoul National University Hospital were included in this study between January 2013 and March 2016. IMEP/ASP treatment consisted of ifosfamide, methotrexate, etoposide, plus native E. coli L-ASP (6,000 IU/m2 on days 1, 3, 5, 7, 9, and 11) or PEG-ASP (2,500 IU/m2 on day 1) every 3 weeks. ASP-related toxicities, toxicity patterns, length of hospital stay, and clinical outcomes were compared between the different treatment groups. RESULTS: The frequency of ASP-related toxicities was similar between the IMEP plus native E. coli L-ASP group and the PEG-ASP group apart from hypofibrinogenemia (native E. coli L-ASP vs. PEG-ASP group, 86.4% vs. 36.8%; p=0.001). Although post-treatment transaminase and albumin levels were significantly high and low, respectively, hepatotoxicity gradients before and after treatment did not differ significantly between the groups. Since PEG-ASP was given at an outpatient clinic in some patients, length of hospital stay was significantly shorter in the IMEP plus PEG-ASP group (median, 4.0 vs. 6.0 days; p=0.002). A favorable tendency of clinical outcomes was observed in NTCL patients treated with IMEP plus PEG-ASP (complete remission rate, 73.7% vs. 45.5%; p=0.067). CONCLUSION: IMEP plus PEG-ASP showed similar ASP-related toxicities, shorter length of hospital stay, and a trend towards improved clinical outcomes compared with IMEP plus native E. coli L-ASP in NTCL.

Desenvolvimento de vesículas poliméricas de poli(etileno glicol)-b-poli(ε-caprolactona) (PEG-PCL) para veiculação de L-asparaginase / Development of polyethylene glycol-polycaprolactone polymer vesicles for L-Asparaginase

A L-Asparaginase (ASNase) é um importante agente quimioterapêutico utilizado para o tratamento da leucemia linfoblástica aguda (ALL) há mais de 40 anos. No entanto, devido à origem biológica da ASNase, enzima produzida por Escherichia coli, problemas como a imunogenicidade e baixa meia vida-plasmática devem ser considerados. Com o objetivo de minimizar essas desvantagens, várias ASNases homólogas bem como formulações de ASNase de E. coli foram investigadas. Nenhuma das formulações desenvolvidas, entretanto, foi capaz de resolver definitivamente esses problemas associados à sua origem. Nesse sentido, considerando os recentes avanços na ciência de polímeros com a possibilidade do obtenção de vesículas poliméricas usando copolímeros, este trabalho concentrou-se no desenvolvimento de polimerossomos de poli(etileno glicol)-b-poli(ε-caprolactona) (PEG-PCL) para encapsular a ASNase. Diversas condições experimentais foram investigadas e, ao final, os polimerossomos foram produzidos pela técnica de hidratação do filme polimérico utilizando a centrifugação como técnica de pós-filme para remoção de copolímero precipitado, produzindo assim vesículas polímericas de 120 a 200nm com PDI de aproximadamente 0,250. A eficiência de encapsulação da ASNase, utilizando as metodologias de centrifugação ou cromatografia de exclusão molecular, revelou taxas de encapsulação de 20-25% e 1 a 7%, repectivamente. Esses resultados apontam a importância de se determinar a eficiência de encapsulação por cromatografia de exclusão molecular ou método direto no caso de nanoestruturas auto-agregadas formadas por copolímeros, devido a valores superestimados com o emprego da centrifugação. Ainda que estudos complementares se façam necessários para liberação da enzima encapsulada ou penetração da L-asparagina nas vesículas, nossos resultados demonstram o potencial de polimerossomos para veiculação de ASNase, bem como de outras proteínas terapêuticas

L-Asparaginase (ASNase) is an important chemotherapeutic agent used for the treatment of acute lymphoblastic leukemia (ALL) for more than 40 years. However, due to the biological origin of ASNase (produced by Escherichia coli) some drawbacks such as immunogenicity and low plasma half life are present. In order to minimize the disadvantages, several ASNases proteoforms and formulations of E. coli ASNase were investigated. However, none of this formulations completely solved the main drawbacks of ASNase. In this sense, considering the recents advances in polymers science with the possibility to develop polymeric vesicles using copolymers, this work aimed at the development of poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-PCL) vesicles to encapsulate ASNase. Different experimental conditions were investigated and, the final polymersomes formulation was prepared by film hydratation using centrifugation as a post-film technique to remove the bulky coplymer. Polymeric vesicles of 120 to 200nm with PDI of approximately, 0.250 were obtained. The encapsulation efficiency of ASNase was determined indirectly by centrifugation and directly by size exclusion chromatography, resulting in encapsulation rates of 20-25% and 1 to 7%, respectively. These results indicate the importance of determining the efficiency of encapsulation by size exclusion chromatography or direct method in the case of self-aggregated nanostructures formed by copolymers, due to values overestimated with the use of centrifugation. Our results point to the potential of polymersomes for ASNase delivery, as well as other therapeutic proteins. Nonetheless, complimentary studies are still necessary for ASNase release or L-asparagine penetration into the vesicles

Avaliação da resistência de formas mutantes da enzima L-asparaginase a proteases séricas humanas / Evaluation of L-asparaginase mutant forms resistance to human serum proteases

O tratamento para a Leucemia Linfoblástica Aguda LLA utiliza, entre outros fármacos, a enzima L-asparaginase (ASNase) proveniente da bactéria Escherichia coli. Reações imunológicas estão entre os problemas do tratamento com ASNase, e a formação de anticorpos contra essa proteína pode impedir o sucesso no tratamento. Duas cisteíno proteases lisossomais estão relacionadas com a degradação de ASNase nos seres humanos, a Catepsina B (CTSB) e Asparagina Endopeptidase (AEP). Em estudos prévios do nosso grupo obteve-se mutantes de ASNase resistentes a degradação por CTSB e/ou AEP in vitro. Nesse trabalho avaliamos essas mutantes quanto a sua citotoxicidade em linhagens celulares de leucemia e conduzimos estudos in vivo, aplicando as proteoformas de ASNases em camundongos Balb C para avaliar a atividade asparaginase sérica das enzimas ao longo do tempo, bem como obter informações sobre a formação de anticorpos contra essas proteoformas. Nos ensaios de citotoxicidade, duas das proteoformas testadas tiveram efeito citotóxico semelhante a forma selvagem, enquanto uma outra proteoforma tem a citotoxicidade sensivelmente reduzida. Já nos ensaios in vivo, uma proteoforma demonstrou meia vida sérica maior da atividade asparaginásica, e duas proteoformas causaram reduzida formação de anticorpos. Juntos, esses resultados colaboram para a obtenção de uma nova geração de ASNases com melhor biodisponibilidade, e efeitos adversos reduzidos, gerando a possibilidade de menores doses e frequência de aplicações

The Treatment for Acute Lymphoblastic Leukemia (ALL) includes the biopharmaceutical L-asparaginase (ASNase) from Escherichia coli. Immunological reactions are among the problems of treatment using ASNase, and the antibodies formation protein may prevent success in treatment. Lysosomal cysteine proteases are related to ASNase degradation, Cathepsin B (CTSB) and Asparagine Endopeptidase (AEP). In previous studies, ASNase mutants resistant to CTSB and / or AEP degradation in vitro were obtained. In this work, mutants were evaluated in cytotoxicity in ALL cell lines and, in vivo studies, applying doses of the wild and mutant ASNases in Balb C mice to evaluate serum asparaginase activity of the enzymes over time, as well as to obtain information on the formation of antibodies against these proteoforms. Regarding to the cytotoxicity, two proteoforms among the tested had similar cytotoxicity than the wild-type. While another proteoform had the cytotoxicity severely reduced. One proteoform have demonstrated greater serum half-life of asparaginase activity, while two other mutants caused reduced antibody formation. Together, these results collaborate to obtain a new generation of ASNases with increased bioavailability and reduced side effects, generating the possibility of lower doses and frequency of applications

Desenvolvimento e caracterização de polimerossomos para veiculação de L-asparaginase / Development and characterization of polymersomes for the release of L-asparaginase

A enzima L-Asparaginase (ASNase) é um biofámaco utilizado no tratamento da leucemia linfoblástica aguda, no entanto, a evolução da produção da ASNase como um medicamento desde o final da década de 1970 resultou em apenas quatro alternativas disponíveis no mercado farmacêutico, com relatos de graves reações imunogênicas e toxicidade. Desse modo, a nanotecnologia é uma plataforma que pode ser explorada para administração dessa enzima diminuindo a exposição da mesma a proteases e aumentando a sua meia-vida aparente. Os polimerossomos (PL) são opções que pela nanoestrutura vesicular poderiam encapsular a ASNase em seu core aquoso e pela presença de uma membrana polimérica, são mais robustos que os lipossomos. Assim, neste trabalho objetivou-se desenvolver PL para encapsulação da ASNase como uma alternativa às formulações deste biofármaco existentes. Foram desenvolvidos PL de PEG-PLA, PMPC-PDPA, PEG-PDPA e Pluronic® L-21. Foram estudados fatores relacionados à composição dos copolímeros (fração hidrofílica, responsividade a fatores externos tais como pH e temperatura) e métodos de elaboração (hidratação do filme polimérico, troca de pH e temperatura) bem como foi feita a caracterização dos PL obtidos (tamanho, índice de polidispersão, espessura de membrana, formação de excessivo bulk polimérico, obtenção de micelas). Também foi feito um planejamento racional para encapsulação da ASNase (hidratação direta do filme polimérico e encapsulação por eletroporação, autoagregação com encapsulação por troca de pH ou de temperatura). Para os PL preparados com PEG-PLA, a extrusão resultou em distribuição de tamanhos mais estreitos correspondentes aos valores de PDI de 0,345, 0,144 e 0,081 para PEG45-PLA69, PEG114-PLA153 e PEG114-PLA180, respectivamente. Foi demonstrado que copolímeros com menor fração hidrofóbica resultam em maior eficiência de encapsulação para proteínas, já que possuem volumes aquosos maiores. Com o PMPC25-PDPA72 foi possível encapsular em média três unidades de ASNase por vesículas através da eletroporação ou troca de pH, sendo que no primeiro método houve formação de túbulos e no último método as micelas não foram completamente removidas. Para PEG100-PDPA80, grandes agregados permaneceram após a purificação levando a um PDI alto, mas não foi observada a formação de túbulos, já a troca de pH para este copolímero resultou em maior perda de copolímeros como bulk polimérico precipitado. Para o copolimero tribloco Pluronic® L-121, foi observado que as vesículas eram estáveis durante uma semana à temperatura ambiente, contrariando o que era descrito na literatura. Nesses sistemas, quando preparados por hidratação do filme, a encapsulação da ASNase foi realizada por eletroporação mas a proteína não foi detectada dentro das vesículas. Atribuímos a não-encapsulação à organização da bicamada Pluronic® L-121 sem conformação definida das cadeias poliméricas, dificultando a reorganização do bloco hidrofílico na porção interna do poro durante eletroporação. Por troca de temperatura, cerca de 5 % de ASNase foi encapsulada e o método resultou em total recuperação da atividade da enzima. Desse modo foram obtidos diferentes PL com diferentes características nanoestruturais de acordo com os copolímeros utilizados para carreamento da ASNase

The enzyme L-Asparaginase (ASNase) is a biopharmaceutical used in the treatment of acute lymphoblastic leukemia, still the industrial production of ASNase as a marketable drug since the late 1970s has resulted in only four alternatives available in the pharmaceutical market, with reports of severe immunogenic reactions and toxicity. In this sense, nanotechnology is a platform that can be exploited to administer this enzyme by decreasing its exposure to proteases and increasing its apparent half-life. Polymerosomes (PL) are interesting routes which by its intrinsically vesicular nanostructure could encapsulate the ASNase in its aqueous core and by the presence of a polymeric membrane, being more robust than the liposomes. Thus, in this work it was intended to develop PL for ASNase encapsulation as an alternative to existing formulations of this biopharmaceutical. PL of PEG-PLA, PMPC-PDPA, PEG-PDPA and Pluronic® L-21 were developed. It was studied the copolymers composition (i.e. hydrophilic fraction, responsiveness to external factors such as pH and temperature), PL design (i.e. polymer film hydration, pH change and temperature) and PL characterization (i.e. size, polydispersity index - PDI, membrane thickness, formation of excessive polymer bulk, micelles production). A suitable experimental planning for ASNase encapsulation (i.e. direct hydration of the polymeric film and encapsulation by electroporation, self-aggregation with encapsulation by pH or temperature change) was also performed. For the PL prepared with PEG-PLA, the extrusion resulted in narrower size distribution corresponding to the PDI values of 0.345, 0.144 and 0.081 for PEG45-PLA69, PEG114-PLA153 and PEG114-PLA180, respectively. It has been shown that copolymers with lower hydrophobic fraction result in higher encapsulation efficiency for proteins, since they have larger aqueous volumes. With PMPC25-PDPA72 PL, it was possible to encapsulate three units of ASNase per vesicles through electroporation or pH change. In the first method, tubules were formed and in the latter one the micelles were not completely removed. For PEO100-PDPA80 PL, large aggregates remained after purification leading to a high PDI value, nevertheless no tubule formation was observed, since the pH change for this copolymer resulted in greater loss of copolymers as a precipitated polymer bulk. For the Pluronic® L-121 triblock copolymer PL, it was observed that the vesicles were stable for one week at room temperature, contrary to what was described in the literature. These PLs were prepared by film hydration method and ASNase encapsulation was performed by electroporation, nonetheless the protein was not detected within the vesicles. It is attributed the non-encapsulation to the organization of the Pluronic® L-121 bilayer without defined conformation of the polymer chains, making it difficult to reorganize the hydrophilic block in the internal portion of the pore during electroporation. By temperature change, about 5% of ASNase was encapsulated and the method resulted in complete recovery of enzyme activity. In conclusion, several PLs with a vast range of differential nanostructural characteristics were obtained according to the copolymers used for ASNase loading