Immunotoxicity of acrylamide in female BALB/c mice / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the immunotoxicity of acrylamide (ACR) in female BALB/c mice.</p><p><b>METHODS</b>A total of 200 female mice weighing 18-22 g were randomly divided into four clusters based on body weight, and each weight-based cluster included five groups (10 mice per group): negative control, positive control (cyclophosphamide), low, intermediate, and high dose ACR groups, and all the groups were administered ACR by gavage for 30 days. At the end of the study, the immunotoxicological effects of the ACR were evaluated through immunopathology, humoral immunity, cellular immunity, and non-specific immunity.</p><p><b>RESULTS</b>The terminal body weight, spleen and thymus weights, lymphocyte counts in the ACR-H group were decreased, pathological changes were observed in lymph glands, thymus and spleen. %T cells in blood lymphocytes were significantly increased in all ACR-treated groups, and a significant reduction of % natural killer(NK) cells and increase of %Th cells were observed in the ACR-H group. interleukin-6(IL-6), Concanavalin A(ConA)-induced splenocyte proliferation and serum half hemolysis value (HC50) were also significantly suppressed in the ACR-H group.</p><p><b>CONCLUSION</b>ACR elicited an inhibitory effect on cellular and humoral immunity of mice after 30 day feeding.</p>

Efficacy of antiangiogenic targeted immunotoxin DTAT and DTATEGF against glioblastoma multiforme / 中南大学学报(医学版)

OBJECTIVE@#To investigate the in vitro and in vivo anticancer efficacy of the immunotoxin DTAT and DTATEGF against globlastoma multiforme.@*METHODS@#The in vitro cytotoxicity of DTAT and DTATEGF was measured using MTT assay. In vivo studies were performed in which 18 nude mice were randomly divided into 3 groups and the glioma xenograft intracranial mouse model was constructed with U87-luc cell line of human glioma. Then 1 μg of DTAT, or DTATEGF, or a control protein Bickel3 was delivered intracranially by convection-enhanced delivery (CED) via an osmotic minipump. The brain tumor fluorescence signal intensity was investigated by bioluminescent imaging (BLI). Microvessel density (MVD) was measured by immunchistochemistry SABC method in each group.@*RESULTS@#In vitro DTAT and DTATEGF were found highly potent against U87-luc cell line, with IC(50) <0.01 nmol/L and IC(50)<1 nmol/L, respectively. In vivo BLI monitoring of the control group showed progressively increasing luminescence, while in the two treatment groups, luminescence was reduced on day 8, and increased slowly (P<0.05). The MVD of DTAT (31.6±5.2)/mm(2) and DTATEGF (25.1±6.5)/mm(2) groups had significant difference with that of the control group (51.3±7.4) /mm(2) (P<0.01).@*CONCLUSION@#Both DTAT and DTATEGF have potential in clinical application against globlastoma multiforme because of their ability to target the tumor cells and neovasculature simultaneously.

Mecanismo de acción de la toxina alfa hemolisina de Escherichia coli / Action mechanism of Escherichia coli alpha-hemolysin toxin / Mecanismo de ação da toxina alfa-hemolisina de Escherichia coli

Escherichia coli es una de las bacterias anaerobias facultativas más predominantes en el intestino, siendo, en la mayoría de los casos, inocua para el huésped. Existen cepas que traslocan al torrente sanguíneo causando enfermedades extraintestinales como infecciones urinarias, septicemia y meningitis. Dentro de éstas se encuentran las cepas uropatogénicas (Uropathogenic Escherichia coli: UPEC), que secretan varios factores de virulencia. Estos últimos incluyen: toxinas, sistemas de adquisición de hierro, adhesinas y antígenos capsulares. Las principales toxinas secretadas son: alfa-hemolisina (HlyA) y el factor necrotizante citotóxico 1 (CNF-1). En esta revisión se presenta una descripción exhaustiva de HlyA, incluyendo su síntesis, maduración y exportación desde la bacteria. La acilación de la proteína en dos residuos internos de lisina la convierte en una toxina muy virulenta al exponer regiones intrínsecamente desordenadas que son esenciales en diferentes pasos del mecanismo de acción de la misma. Específicamente, la exposición de estas regiones está involucrada en interacciones proteína-proteína dentro del proceso de oligomerización. La formación del oligómero es responsable de la permeabilidad inducida en las células blanco. Finalmente, basado en los conocimientos acerca de las características estructurales y funcionales de HlyA, se presentan potenciales usos de HlyA en terapias basadas en toxinas.

Escherichia coli is one of the predominant species of facultative anaerobes in the human gut, and in the majority of the cases it is harmless to the host. Some strains of this species can translocate to blood and cause infection such as urinary infection, septicemia and meningitis. These are the uropathogenic E. coli strains (UPEC) that secrete a number of virulence factors. The latter include a number of secreted toxins, iron-acquisition systems, adhesins, and capsular antigens. Secreted toxins include HlyA, the cytotoxic necrotizing factor-1 (CNF-1). In this review an exhaustive description of the toxin has been delineated, including its synthesis, maturation, and export from the bacteria. The acylation of the protein at two internal lysine residues gives the toxin its virulence, by exposing intrinsic disordered regions that are essential in different steps of the toxin's mechanism of action. The further exposure of regions involved in the protein-protein interaction within the oligomerization process is responsG-ible for the permeability induced in all the target cells. Based on the already known structural and functional characteristics of HlyA, the potential use in toxin-based therapy is presented.

Escherichia coli é uma das bactérias anaérobias facultativas mais predominantes no intestino, sendo na maioria dos casos inócua para o hóspede. Há cepas que passam ao torrente sanguíneo causando doenças extraintestinais como infecção urinária, septicemia e meningite. Dentro destas se encontram as cepas uropatogênicas (Uropathogenic Escherichia coli: UPEC) que secretam varios fatores de virulência. Estos últimos incluem: toxinas, sistemas de aquisição de ferro, adesinas e antígenos capsulares. As principais toxinas secretadas são: alfa hemolisina (HlyA) e o fator necrotizante citotóxico 1 (CNF-1). Nesta revisão apresenta-se uma descrição exaustiva de HlyA incluindo sua sintese, seu amadurecimento e exportação a partir da bactéria. A acilação da proteína em dois residuos internos de lisina a transforma numa toxina muito virulenta ao expor regiões intrinsecamente desordenadas que são essenciais em diferentes passos do mecanismo de ação da mesma. Especificamente, a exposição destas regiões esta envolvida em interações proteína-proteína dentro do processo de oligomerização. A formação do oligômero é responsável pela permeabilidade induzida nas células alvo. Finalmente, com base nos conhecimentos acerca das características estruturais e funcionais de HlyA, apresentam-se potenciais usos de HlyA em terapias baseadas em toxinas.

Efficacy of bispecific targeted immunotoxin DTATEGF against NSCLC brain metastatic tumor PC9-BrM3 cells / 中南大学学报(医学版)

OBJECTIVE@#To investigate the in vitro and in vivo anticancer efficacy of the immunotoxin DTATEGF against human NSCLC brain metastatic tumor PC9-BrM3 cell line.@*METHODS@#The effect of the immunotoxin DTATEGF was tested for its ability to inhibit the proliferation of PC9-BrM3 cells in vitro by MTT assay. The cell cycle and the apoptosis of cells with 1 pmol/L DTATEGF were examined by flow cytometry. In vivo, 2 μg of DTATEGF or control Bickel3 was given intratumor to nude mice with established PC9-BrM3 xenografts on their hips, and tumor volumes were measured and tumor samples were investigated by immunchistochemistry SABC method. The microvessel density (MVD) was measured in each group.@*RESULTS@#In vitro, DTATEGF killed PC9-BrM3 cells and showed an IC50 of 1 pmol/L. The apoptotic rate in the 1 pmol/L DTATEGF group was (64.0±0.5)% , significantly higher than that in the control group (1.5±0.4)% (P<0.01). The cell cycle was obviously inhibited by DTATEGF in a dose-dependent manner. The percentage of cells treated with 1 pmol/L DTATEGF in SubG0/G1 phase was (32.0±1.5)%, significantly higher than that in the control group (2.0±0.4)% (P<0.01). In vivo, DTATEGF significantly inhibited the growth of PC9-BrM3 hip tumors (P<0.05). The MVD of the DTATEGF group was (15.6±4.6)/mm2, significantly lower than that of the control group (31.2±5.4)/mm2 (P<0.01).@*CONCLUSION@#DTATEGF inhibits the growth of the PC9-BrM3 cell line and induces its apoptosis. It is highly efficacious against human metastatic NSCLC brain tumor and against neovascularization.

Nucleic Acid Aptamers: New Methods for Selection, Stabilization, and Application in Biomedical Science

The adoption of oligonucleotide aptamer is well on the rise, serving an ever increasing demand for versatility in biomedical field. Through the SELEX (Systematic Evolution of Ligands by EXponential enrichment), aptamer that can bind to specific target with high affinity and specificity can be obtained. Aptamers are single-stranded nucleic acid molecules that can fold into complex threedimensional structures, forming binding pockets and clefts for the specific recognition and tight binding of any given molecular target. Recently, aptamers have attracted much attention because they not only have all of the advantages of antibodies, but also have unique merits such as thermal stability, ease of synthesis, reversibility, and little immunogenicity. The advent of novel technologies is revolutionizing aptamer applications. Aptamers can be easily modified by various chemical reactions to introduce functional groups and/or nucleotide extensions. They can also be conjugated to therapeutic molecules such as drugs, drug containing carriers, toxins, or photosensitizers. Here, we discuss new SELEX strategies and stabilization methods as well as applications in drug delivery and molecular imaging.

Antibody-drug conjugates and their application in the treatment of hematological malignancies / 药学学报

Monoclonal antibody-targeted therapy has been a hot spot in current clinical cancer treatment. As current antibody drugs have large molecule sizes leading to poor tissue penetration, and high dosage in clinical application leading to high cost, to overcome the problems, the development of new antibody drugs with miniaturization and high potency has become a new trend. In recent years, the conjugates of monoclonal antibodies and cytotoxins, called antibody-drug conjugates (ADCs), have entered the arsenal of anti-cancer drugs, becoming a new format of antibody drugs and attracting extensive attentions. The ADC molecule usually consists of antibody, linker and effector molecule. According to different effector molecules, ADCs can be divided into three categories as chemo-conjugates, immunotoxins and radio-conjugates. When ADC molecules are internalized into cancer cells, cytotoxins will be released by chemical, enzyme degradation or by action of lysosomal proteases, then kill targeted cells by inhibiting protein synthesis, depolymerizing microtubules or breaking double-strand DNA. Recently, two ADC drugs have been approved by the US FDA and more ADC drug candidates are in clinical phase II or III trials which show significantly clinical effects and attracting much attention and competition of pharmaceutical enterprises. In this review, antibody conjugates in the past and present will be summarized and the future development trends and challenges of this type of antibody drugs will be discussed.

Development of antibody drugs targeting against HER2 for cancer therapy / 药学学报

Human epidermal growth factor receptor 2 (HER2) belongs to the transmembrane glycoprotein receptor family. Overexpression of HER2 could directly lead to tumorigenesis and metastasis. This phenomenon could be observed in the breast cancer, ovarian cancer, gastric cancer, lung cancer and prostate cancer. Compared with the conventional chemotherapy, the targeted treatment of antibody is more specific and has lower side effects. This review describes the current status of monotherapy and combination therapies of anti-HER2 antibodies, trastuzumab and pertuzumab, with chemotherapeutic drugs. The development trends of new formats of anti-HER2 antibody drugs such as bispecific antibody, immunotoxin are also discussed.

Preliminary study to characterize differences in potential immunomodulatory effects of cyclosporine A using BALB/c and ICR mouse splenocytes / Estudo preliminar para caracterizar as diferenças nos efeitos imunomodulatórias de ciclosporina A esplenócitos usando BALB / c e ICR do mouse

Cyclosporine A (CsA) is widely used as an immunosuppressant for the treatment of autoimmune diseases and immune regulation in transplant patients. Due to its wide applicability, studies of unwanted side effects of CsA are imperative. It has been found that not all patients treated with CsA display the same types/patterns of adverse effects. To ascertain the bases for these differential responses, potential differing effects of CsA on B-lymphocytes were analyzed. This entailed an assessment of changes in CsA viability and mitotic activity within splenocyte populations from BALB/c and ICR mice. These particular strains were examined because: (1) in each of them, previously have been shown that differed in the respond to biological response modifiers, such as bacterial agents, and/or immunogens; (2) our own earlier studies showing strain-associated differences in ex vivo splenocyte/lymphocyte responses to other drug; and, (3) a potential immunomodulatory effect of any agent should be studied in at least two different strains during a broad toxicological evaluation. Splenocytes from each strain were treated with 200 μg/mL CsA, and CD4+, CD8+, and CD19+ cell viabilities were monitored at various time points during the exposure period. In general, there appeared to be a trend toward greater decreases in viability among BALB/c B-lymphocytes than their ICR counterparts as incubation progressed. Differences related with T-lymphocyte sensitivity to drug associated to strains was not observed, because it was uniformly lethal throughout. With regard to mitotic activity, cells from ICR mice were more susceptible to inhibition of spontaneous cell division at low concentrations of CsA (relative to the rates of blastogenesis by BALB/c counterparts). At higher concentrations of the drug however, there were no differences in the sensitivity of each strain. This work provides new insight into the mechanism of action of CsA and illustrates the need for at least two different strains of mice/rodents for the evaluation of the overall toxicological potential of any test agent.

Ciclosporina A (CsA) é amplamente usada como imunossupressor para o tratamento de doenças autoimunes e regulação imune nos pacientes transplantados. Devido à alta aplicabilidade, são imperativos os estudos sobre seus efeitos colaterais indesejáveis. Descobriu-se que nem todos os pacientes tratados com CsA apresentam os mesmos tipos/padrões de efeitos adversos. Para averiguar as bases dessas respostas diferentes, analisaram-se efeitos potenciais diferentes da CsA nos linfócitos B. Isto envolveu a avaliação de alterações na viabilidade da CsA e da atividade mitótica dentro das populações de esplenócitos de camundongos BALB/c e ICR. Essas espécies, em particular, foram examinadas porque: (1) cada uma delas mostrou, previamente, respostas diferentes a modificadores de respostas biológicas, tais como agentes bacterianos e/ou imunogênicos; (2) nossos estudos anteriores mostraram diferenças associadas às espécies em respostas ex vivo de esplenócitos/linfócitos a outro fármaco e (3) qualquer efeito imunomodulatório potencial de um agente em teste deveria ser estudado, no mínimo, em duas espécies diferentes durante a avaliação toxicológica ampla. Esplenócitos de cada espécie foram tratados com 200 μg/mL de CSA e a viabilidade das células CD4+, CD8+ e CD19+ foi monitorada em vários tempos durante o período de exposição. No geral, parece haver uma tendência em relação a aumentos maiores na viabilidade entre os linfócitos B de BALB/c do que no de ICR, à medida que a incubação progride. Não se observou diferenças na sensibilidade do linfócito T, uma vez que o fármaco foi uniformemente letal. Com relação à atividade mitótica, as células de camundongos ICR se mostraram mais suscetíveis à inibição da divisão celular espontânea em baixas concentrações de CsA (relativamente às taxas de blastogênese de BALB/c). Em concentrações maiores do fármaco, entretanto, não houve diferenças na sensibilidade em cada uma das espécies. Este trabalho propicia nova visão do mecanismo de ação de CsA e ilustra a necessidade de, pelo menos, duas espécies diferentes de camundongos/roedores para a avaliação da toxicidade potencial de qualquer agente em teste.

Clinical development of experimental therapies for malignant glioma

Advances in medical and surgical treatments in the last two to three decades have resulted in quantum leaps in the overall survival of patients with many types of non-central nervous system [CNS] malignant disease, while survival of patients with malignant gliomas [WHO grades 3 and 4] has only moderately improved. Surgical resection, external fractionated radiotherapy and oral chemotherapy, during and after irradiation, remain the pillars of malignant glioma therapy and have shown significant benefits. However, numerous clinical trials with adjuvant agents, most of them administered systemically and causing serious complications and side effects, have not achieved a noteworthy extension of survival, or only with considerable deterioration in patients' quality of life. Significant attention was focussed in the last decades on the cell biology and molecular genetics of gliomas. Improved understanding of the fundamental features of tumour cells has resulted in the introduction and increasing clinical use of local therapies, which employ spatially defined delivery methods and tumour-selective agents specifically designed to be used in the environment of a glioma-invaded brain. This review summarises the key findings of some of the most recent and important clinical studies of locally administered novel treatments for malignant glioma. Several such therapies have shown considerable anti-tumour activity and a favourable profile of local and systemic side effects. These include biodegradable polymers for interstitial chemotherapy, targeted toxins administered by convection enhanced delivery, and intra- and peritumourally injected genetically modified viruses conferring glioma-selective toxicity. Areas of possible improvement of these therapies and essential future developments are also outlined

Target-specific cytotoxic activity of recombinant fusion toxin C-CPE-ETA' against CLDN-3,4-overexpressing ovarian cancer cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>The aim of this study was to explore the possibility of creating a toxin, C-CPE-ETA', by fusing C-terminal high affinity binding domain of CPE (C-CPE) with a truncated form of Pseudomonas aeruginosa exotoxin A (ETA') and to examine whether C-CPE-ETA' could specifically target CLDN-3, 4 molecule and the targeted toxin was cytotoxic against CLDN-3,4-overexpressing ovarian cancer.</p><p><b>METHODS</b>CLDN-3 and CLDN-4 expressions were analyzed at the mRNA level in three ovarian cancer cell lines and epithelial ovarian cancer tissues from 20 patients. After transforming an expression plasmid of C-CPE-ETA' into E. coli BL21 (DE3) plysS strain, the recombinant protein was purified using His-Bind resin chromatography column and analyzed by Western blot and Coomassie blue staining. The specific binding, proapoptotic and cytolytic activities were evaluated by flow cytometry, fluorescence microscopy with the JC-1 probe and MTT assay in CLDN-3,4-overexpressing ovarian cancer cells.</p><p><b>RESULTS</b>Quantitive RT-PCR results showed there existed high levels of CLDN-3 and CLDN-4 in ovarian cancer cells, CAOV3, OVCAR3 and SKOV3. Moreover, high expressions of CLDN-3 and CLDN-4 were observed in 90.0% (18/20) and 60.0% (12/20) of ovarian cancer tissues, with an expression level 10-fold higher than that in the normal ovarian tissue. A 58 000 recombinant protein C-CPE-ETA' was demonstrated by Western blot and Coomassie blue staining. Purified and recombinant C-CPE-ETA' was bound with high affinity to CLDN-3,4-overexpressing ovarian cancer cells, CAOV3, OVCAR3 and SKOV3 cells. C-CPE-ETA' was strongly proapoptotic and cytotoxic towards the CLDN-3,4-overexpressing ovarian cancer cells. The concentration of IC(50) was 7.364 ng/ml for CAOV3 cells, 8.110 ng/ml for OVCAR3 cells and 22.340 ng/ml for SKOV3 cells, respectively. However, control CLDN-3,4-deficient cell line HUVEC was not susceptible to the recombinant C-CPE-ETA' at a concentration up to 10 µg/ml.</p><p><b>CONCLUSIONS</b>The C-CPE-ETA' protein exhibits remarkably specific cytotoxicity for CLDN-3,4-overexpressing ovarian cancer cells. Its therapeutic potential warrants further development for ovarian cancer molecular targeted therapy.</p>

Estudo dos mecanismos de ação da hidroquinona e fenol sobre o recrutamento leucocitário em respostas inflamatórias / Study of mechanisms of action of hydroquinone and phenol on leukocyte recruitment in inflammatory response

Hidroquinona (HQ) é um dos metabólitos do benzeno responsáveis pelos efeitos tóxicos da exposição ao solvente, além de ser componente da dieta, medicamentos, cigarro e poluente do meio ambiente. Considerando a imunotoxicidade desta substância, o grupo de pesquisa do laboratório investiga o papel da exposição à HQ por período prolongado de tempo sobre respostas inflamatórias agudas (RIA). Neste contexto, o presente trabalho avaliou os efeitos desta exposição sobre os mecanismos vasculares e celulares da RIA de diferentes doses diárias de HQ (5, 10 ou 50 mg/kg) em ratos Wistar machos, via i.p., por 17 ou 22 dias, uma vez ao dia, com intervalos de 2 dias a cada 5 doses. Animais controles receberam o veículo (salina com 5% etanol). A resposta inflamatória aguda inata foi induzida pela administração de glicogênio de ostra (1% em PBS, 5 mL) na bolsa subcutânea dorsal ou pela instilação de lipopolissacarídeo de Salmonella abortus (LPS; 100 µL de solução 100 µg/mL); A resposta inflamatória aguda adquirida foi provocada pela inalação de ovalbumina (10 mL de solução de OA 1% PBS, 15 min) em animais previamente sensibilizados (10 µ/100mg AI(OH)3 no décimo dia de exposição). Os resultados obtidos mostraram que: 1) o aumento do número de leucócitos na bolsa dorsal de animais expostos a 50 mg/kg de HQ é dependente, pelo menos em parte, da maior interação de leucócitos circulantes à parede vascular da microcirculação, mas não é decorrente de alterações na reatividade microvascular; o aumento de expressão de moléculas de adesão (ß2 integrina), que pode ser a responsável pelo aumento de interaçãoleucócito-endotélio e migração celular; 2) a redução da migração de leucócitos para o pulmão inflamado pelo LPS em animais expostos a HQ, nas menores doses, não foi decorrente de modificações na interação leucócito-endotélio, nem da expressão de moléculas de adesão nos leucócitos circulantes ou na célula endotelial do tecido pulmonar; 3) a redução da migração celular para o pulmão durante a RIA alérgica em animais expostos a 5, 10 ou 50 mglkg de HQ é dependente, pelo menos em parte, da menor concentração de anticorpos anafiláticos circulantes e conseqüentemente da desgranulação reduzida de mastócitos teciduais, visualizados no leito mesentérico após desafio in situ pela OA. A menor produção de anticorpos anafiláticos pode ser decorrente da ação da HQ em diferentes tipos celulares, uma vez que foi observada expressão reduzida de moléculas co-estimulatórias em linfócitos do baço (CD45R e CD6), menor atividade microbicida de macrófagos peritoniais frente a Candida albicans e menor secreção de interferon-γ por células do peritônio. Em conjunto, os resultados apresentados mostram os mecanismos da HQ sobre a resposta do organismo ao trauma de diferentes origens, interferindo com tipos celulares distintos envolvidos nas reações

Hydroquinone (HQ) is one of the metabolites of benzene responsible for the toxic effects of exposure to solvent, as well as being part of the diet, medicines, tobacco and polluting the environment. Considering the immunotoxicity of this substance, our laboratory has investigated the role of exposure to HQ by prolonged period of time on acute inflammatory responses (AIR). In this context, this study evaluated the effects of this exposure on the vascular and cellular mechanisms of AIR of different daily doses of HQ (5, 10 or 50 mg/kg) in male rats, via ip, for 17 or 22 days, a once a day, with intervals of 2 days every 5 doses. Control animais received the vehicle (saline with 5% ethanol). Innate AIR was induced by the administration of oysters glycogen (1% in PBS, 5 mL) into subcutaneous back pouch or by instillation of lipopolysaccharide of Salmonella aborius (LPS, 100 µL of solução100 µg/mL); Allergic AIR gained was caused by inhalation of ovalbumin (10 mL solution of 1% OA in PBS, 15 min) in previously sensitized animal (10 µ/100mg AI (OH)3 on the tenth day of exposure). Results showed that: 1) the increased number of white blood cells back into the pouch of animais exposed to 50 mg/kg of HQ is dependent, at least in part, of higher interaction of circulating leukocytes to the vascular wall of the microcirculation, but is not due to changes in microvascular reactivity; an increase of expression of molecules of accession (ß2 integrin), which may be responsible for the enhanced interaction of leukocyteendothelial and cell migration 2) the reduced migration of leukocytes into the lung inflamed by LPS in animals exposed to 5 or 10 mg/kg was not due to changes in the interactions of leukocyte to endothelium, either the expression of adhesion molecules in circulating white blood cells or in cell endothelial lung tissue, 3) the reduced cell migration to the lungs during the AIR allergic to animais exposed to HQ, in lower doses, is dependent on lower concentration of· circulating anaphylactics antibodies which may be responsible for the mast cell desgranulation. The lower amount of anaphylatic antibodies in the circulation may be due to action of HQ in different cells, as reduced expression of co-stimulatory molecules by Iymphocytes (CD45R and CD6), lower microbicide activity of macrophages and reduced secretion of interferon-γ by peritoneal cells were detected. Together, the results show the toxicity of HQ on the body's response to trauma from different sources, interfering with different cell types involved in the reactions

Targeted killing of the Nalm-6 cells with 2E8-Genistein immunotoxin and its mechanism / 中华儿科杂志

<p><b>OBJECTIVE</b>Leukemia is the most common hematopoietic malignancies in children. Chemotherapy is currently the primary modality of treatment for this fatal disease. Although chemotherapy is very effective in terms of cell killing, severe side effects such as severe infections, intracranial hemorrhage etc. are frequently encountered due to its poor selective damage between normal and malignant cells or tissues. Thus, a new therapy with highly selective killing of malignant cells which leaves the normal cells unaffected is desperately desired. The aim of this study was to investigate the targeting efficacy in vitro with a new clone of anti-human CD19 antibody immunotoxin 2E8-Genistein on B lineage leukemia cell line Nalm-6 cells and its mechanisms in order to provide the evidence of target therapy on B lineage leukemia and lymphoma.</p><p><b>METHODS</b>2E8-Genistein immunotoxin was generated by conjugating Mab 2E8 with a tyrosine kinase inhibitor, Genistein (Gen) via the Sulfo-SANPAH, an ultra-violet sensitive reagent. Nalm-6, a CD19+ B cell leukemia cell line, was used as target cells, while Molt-3, a CD19-T cell leukemia cell line, was taken as the negative control. The morphology of the cells was observed under the reverted reversed light microscope and the viability was checked with either trypan blue exclusion or MTT methods. Two-color flow cytometry was applied to study the mechanism of cell killing.</p><p><b>RESULTS</b>After 24 hours of culture, 2E8-Genistein showed marked target killing on Nalm-6 cells at nine different concentrations from 20 nmol/L through 100 nmol/L with cell survival rates from (71.8 +/- 7.9)% down to (16.6 +/- 12.9)%, respectively (n = 3), which were all significantly lower than that of control group (100 +/- 13.9)% (P < 0.05). The killing effect was even more significant when the concentration was over 80 nmol/L. The growth inhibition rates of this immunotoxin on Nalm-6 cells were 82%, 84% and 94%, respectively at 24, 48 and 72 hours of culture in a time dependent manner. Significant difference was observed between the cell growth curve of Nalm-6 cultured with 100 nmol/L of 2E8-Gen and those of Nalm-6 cultured with medium (blank), PBS (negative control) or the same concentration of pure 2E8 antibody (negative control) groups (F = 152.15, P = 2.15 x 10(-7)), but there was no significant difference among the three control groups (F = 1.51, P = 0.29). When Molt-3 cells were used as target cells, the cell growth curves of Molt-3 cultured with 2E8-Gen (100 nmol/L) and with negative control of blank did not show any significant difference (F = 0.34, P = 0.59). PI/FITC Annexin V double staining analysis with flow cytometry showed that the positive rate (33.45 +/- 8.77)% of early apoptosis on Nalm-6 cells induced by 100 nmol/L of 2E8-Genistein was significantly higher than that of negative control of blank (10.44% +/- 1.28%, t = -4.39, P = 0.001) at 24 hours of culture.</p><p><b>CONCLUSION</b>2E8-Genistein immunotoxin can significantly target the Nalm-6 cells in vitro in a time response manner and the apoptosis induction is involved in the course of this killing effect.</p>

Antibody-drug conjugates as targeted cancer therapeutics / 药学学报

Traditional chemotherapy has become one of the essential treatments of cancer. However, cytotoxic agents are not tumor specific, which would cause serious side effects. Antibody-drug conjugates (ADCs), also called immunoconjugates, belong to the "targeted chemotherapeutics" category of anti-cancer drugs. ADCs are composed of three components including the cytotoxic drug, the monoclonal antibody, and the linker connecting the drug to the antibody. With the special-binding between antibody and antigen expressed on the surface of targeted cancer cells, ADCs provide a method to achieve excellent localization of the drug at the desired site in the body. The internalization and formation of ADCs are crucial in designing and applying an antibody conjugate to a particular disease model. In this review, we summarize three distinct internalization routes of ADCs and analysis the structure of ADCs. We also discuss in detail the categories and interaction of every component, as well as their influence to targeting property, liability and activity.

Antitumor effect of nanospheres coupled with the anti-human liver cancer monoclonal antibody HAb18 / 南方医科大学学报

<p><b>OBJECTIVE</b>To prepare nanospheres coupled with the anti-human liver cancer monoclonal antibody HAb18 and evaluate its immunoreactivity and antitumor effects.</p><p><b>METHODS</b>The nanosphere coupled with the antibody was prepared by intermolecular cross-linking the anti-human liver cancer monoclonal antibody, HAb18, with human serum albumin nanospheres containing ADM [termed HAS(ADM)-NS] via a new hetero-bifunctional cross-linker SPDP. Condensation test and immunofluorescence assay were used to evaluate the immunoreactivity of the nanospheres, and specific binding of HAb18-HAS(ADM)-NS with liver cancer cell line SMMC-7721 was observed with optical and electron microscopes. The specific cytotoxic effects on the target cells were evaluated in vitro by MTT assay. HAb18-HAS(ADM)-NS, HAS(ADM)-NS and ADM were injected separately into nude mice bearing human liver carcinoma to evaluate the inhibitory activity of HAb18-HAS(ADM)-NS in vivo.</p><p><b>RESULTS</b>The immunoreactivity of HAb18-HAS(ADM)-NS was well preserved. HAb18-HAS(ADM)-NS could bind specifically with the SMMC-7721 cells. The IC(50) of HAb18-HAS(ADM)-NS against SMMC-7721 cells was 44.6 microg/ml, lower than that of HAS(ADM)-NS (345.5 microg/ml) and ADM (365.5 microg/ml). The inhibition rate of HAb18-HAS(ADM)-NS on the growth of liver cancer xenografts was significantly higher than that of HAS(ADM)-NS and ADM (P<0.001).</p><p><b>CONCLUSION</b>HAb18-HAS(ADM)-NS has immunoreactivity and can actively and specifically target the liver cancer cells. The antitumor activity of HAb18-HAS(ADM)-NS is significantly higher than that of HAS(ADM)-NS and ADM.</p>

Preparation of the immunotoxin 2E8-norcantharidin and its targeting killing effect in vitro / 中华儿科杂志

<p><b>OBJECTIVE</b>Monoclonal antibody (mAb) conjugated with certain toxin to generate immunotoxin bears an important and promising effect as a new therapy for patients with hematopoietic malignancies. However, most toxic moieties conjugated with antibody proteins reported in the literature were toxic proteins which presented immunogenicity to patients capable of inducing anti-toxin antibody. Norcantharidin (NCTD) is a small molecule toxin. It does not have the immunogenicity to human body so that it bears a promising potential for development of new targeting drug. In this study, a new clone of self-made anti-CD19 mAb named ZCH-4-2E8 conjugated with NCTD was used to investigate its targeting efficacy against CD19+ lymphoid malignant Nalm-6 cells in vitro to provide the experimental data for the further development of this new targeting agent.</p><p><b>METHODS</b>A monoclonal antibody named 2E8 was prepared from mouse ascites and purified by gel chromatography. The purity of the antibody protein was checked by SDS-PAGE assay. Immunotoxin 2E8-NCTD was successfully generated through conjugating CD19 mAb protein and Norcantharidin by the activated ester method. The binding activity of the immunoconjugate (2E8-NCTD) against CD19 antigens on cell surface and the expression levels of CD19 antigens on Nalm-6 and K562 cells were examined by flow cytometry. Comparisons of the inhibitory effects among PBS, purified 2E8 antibody, norcantharidin and immunotoxin 2E8-NCTD groups on cell growth of either Nalm-6 cells or K562 cells were made.</p><p><b>RESULTS</b>The purity of the purified 2E8 antibody was higher than 99.00% demonstrated by SDS-PAGE assay. 2E8 antibody in the supernatant reacted with 99.34% of Nalm-6 cells, while only 0.98% of K562 cells reacted with this antibody. The newly generated immunotoxin (2E8-NCTD) had a positive rate of 99.90% on Nalm-6 cells with little reduction of binding activity. From the in vitro study, both 2E8-NCTD and norcantharidin were shown to have significant inhibitory effects on the growth of CD19+ Nalm-6 cells (P < 0.001), while the purified 2E8 antibody did not show any significant influences on the growth of Nalm-6 cells. Since no significant inhibitory effects were identified among immunotoxin 2E8-NCTD, 2E8 antibody and control groups on CD19(-) K562 cells, a significant targeting effect of the 2E8-NCTD against Nalm-6 cells was confirmed.</p><p><b>CONCLUSIONS</b>The immunotoxin 2E8-NCTD was successfully synthesized by activated ester method with an excellent targeting killing effect on CD19+ Nalm-6 leukemia cells in vitro, which provides some experimental data for the further development of this new targeting agent.</p>

Anti-human IgG-dextran-adriamycin conjugate for immunotargeting of S180 sarcoma: effects on the tumor weight and survival time of the tumor-bearing mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To prepare anti-human IgG-dextran-adriamycin conjugate for immunotargeting of S180 sarcoma and assess its effects on the tumor weight and survival time of the tumor-bearing mice.</p><p><b>METHODS</b>Anti-human IgG-dextran- adriamycin was synthesized by conjugating dextran and adriamycin with anti-human IgG. The immunoactivity of anti-human IgG-dextran-adriamycin was measured by enzyme-linked immunosorbent assay (ELISA), and the cytotoxicity of anti-human IgG, adriamycin, and the IgG-dextran-adriamycin conjugate against the tumor cells in vitro was evaluated using MTT assay. In mice bearing S180 sarcoma, the agents were tested for their effects against tumor cell growth and the survival time of mice.</p><p><b>RESULTS</b>The molar ratio of anti-mouse IgG, dextran, and adriamycin was 1:2.5:38 in the conjugate. The conjugates were shown to retain the immunoactivity of anti-human IgG, and possessed cytotoxicity to S180 cells in vitro. Administration of the conjugate and intratumor injection of human IgG resulted in a tumor suppression rate of 17.72%in mice bearing S180 sarcoma, but did not prolong the survival time of the mice.</p><p><b>CONCLUSION</b>The anti-human IgG-dextran-adriamycin conjugate shows targeted antitumor effect against S180 sarcoma in mice.</p>

An expression plasmid encoding recombinant immunotoxin IP10-DT390 suppresses the experimental autoimmune encephalomyelitis / 生物医学工程学杂志

Experimental autoimmune encephalomyelitis (EAE) is an autoimmune disease of the central nervous system (CNS); it serves as a model for the human multiple sclerosis (MS). In mice, EAE is mediated by T cells specific for various myelin basic proteins which migrate from the periphery to the CNS. In search of a way to prevent the induction and progression of EAE, we observed the effects of recombinant immunotoxin IP10-DT390 on blocking or eliminating the active T cells in the EAE model. In this paper is presented an experimental gene therapy-based model in which the mice were made resistant to EAE induction by plasmid DNA encoding recombinant immunotoxin that was injected into the leg muscles of mice. The new immuno-biological construct could selectively impair autoreactive T-cell homing while the duration of clinical signs is shorter, and the new construct would not affect other components of the immune response. These data demonstrated the effectiveness of the constructs in the treatment of EAE and suggested its usefulness in the treatment of other autoimmune diseases.

Antitumor effect of recombinant immunotoxin EGF-TCS in nude mice bearing human hepatocellular carcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the anti-tumor effect of recombinant toxin EGF-TCS against transplanted human hepatocellular carcinoma in nude mice.</p><p><b>METHODS</b>Human hepatocellular carcinoma BEL-7,402 cells were inoculated subcutaneously in the right axillary region of nude mice, and 6 days later, EGF-TCS was injected intravenously at 100, 50, and 25 microg/kg. The mice were executed on the next day of drug withdrawal and the tumors were weighed and the tumor inhibition rate calculated. Immunohistochemistry was also performed on the tumor tissues to provide clue for the possible pathways of tumor inhibition.</p><p><b>RESULTS</b>EGF-TCS markedly inhibited the tumor growth in nude mice, with a tumor inhibition rate of 71.3%, 60.87% and 45.22% corresponding to EGF-TCS dosage of 100, 50, and 25 microg/kg, respectively. Variance analysis suggested that EGF-Linker-TCS could significantly inhibit the tumor growth in the mice (F=8.712, P=0.006), and immunohistochemistry showed significantly inhibited angiogenesis in the tumors by EGF-TCS. No blood vessels were found in the tumor tissues in high dosage group, and there were also reduced blood vessels in the other two smaller dose groups in comparison with the untreated model group, indicating that EGF-TCS inhibited tumor growth and migration by inhibiting tumor angiogenesis.</p><p><b>CONCLUSION</b>EGF-TCS can inhibit the growth of solid tumors in nude mice, suggesting the potential value of this preparation in cancer therapy.</p>

Therapeutic effect of a new recombinant immunotoxin mMIP-1alpha-DT390 on experimental autoimmune encephalomyelitis / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the therapeutic effect of a new recombinant immunotoxin mMIP-1alpha-DT390 on experimental autoimmune encephalomyelitis (EAE).</p><p><b>METHODS</b>EAE was induced in the low-sensitive strain C57BL/6 mice with intraperitoneal injection of myelin basic protein (MBP) to simulate the human disease multiple sclerosis, followed by intramuscular injection of cationic liposome carrying the plasmid DNA SRalpha-mMIP-1alpha-DT390 in the leg muscle to elicit resistance to EAE development. The mice were then examined daily for clinical signs of EAE by an observer blind to the treatment protocol. For immunohistochemistry the mice were anesthetized and perfused with sterile PBS and paraformaldehyde, and the cerebrum, cerebellum, medulla and spinal cord were removed for preparation of serial sections. The mononuclear cells (MNCs) from the EAE mouse spleens were prepared for three-color flow cytometry analysis of the surface markers with appropriate antibodies following the BD Pharmingen cytokine staining protocol.</p><p><b>RESULTS</b>EAE model was successfully established by active MBP immunization in C57BL/6 mice. Administration of the immunotoxin mMIP-1alpha-DT390 significantly delayed the disease onset and lowered the mean clinical score for EAE as compared with the control mice. Immunohistochemistry demonstrated much less CCR5(+) infiltrating cells in the central nervous system in mMIP-1alpha-DT390-treated mice than in the control. The treatment also eliminated reactive T cells in the periphery blood without affecting the number of B cells.</p><p><b>CONCLUSION</b>The immunotoxin mMIP-1alpha-DT390 can attenuate the disease activity of EAE in mice, suggesting its potential use in the treatment of other autoimmune disorders.</p>

Construction of an immunotoxin by linking a monoclonal antibody against the human epidermal growth factor receptor and a hemolytic toxin

Hybrid molecules obtained through conjugation of monoclonal antibodies and toxins constitute an approach under exploration to generate potential agents for the treatment of cancer and other diseases. A frequently employed toxic component in the construction of such immunotoxins is ricin, a plant toxin which inhibits protein synthesis at ribosomal level and so requires to be internalized by the cell. A hemolytic toxin isolated from the sea anemone Stichodactyla helianthus, which is active at the cell membrane level, was linked through a disulfide bond to the anti-epidermal growth factor receptor monoclonal antibody ior egf/r3. The resulting immunotoxin did not exhibit hemolytic activity except under reducing conditions. It was toxic for H125 cells that express the human epidermal growth factor receptor, but non-toxic for U1906 cells that do not express this receptor.