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1.
Mol Cancer Ther ; 22(6): 765-777, 2023 06 01.
Article in English | MEDLINE | ID: mdl-37042205

ABSTRACT

MET, the cell-surface receptor for the hepatocyte growth factor/scatter factor, which is widely overexpressed in various solid cancer types, is an attractive target for the development of antibody-based therapeutics. BYON3521 is a novel site-specifically conjugated duocarmycin-based antibody-drug conjugate (ADC), comprising a humanized cysteine-engineered IgG1 monoclonal antibody with low pmol/L binding affinity towards both human and cynomolgus MET. In vitro studies showed that BYON3521 internalizes efficiently upon MET binding and induces both target- and bystander-mediated cell killing. BYON3521 showed good potency and full efficacy in MET-amplified and high MET-expressing cancer cell lines; in moderate and low MET-expressing cancer cell lines good potencies and partial efficacy were observed. In mouse xenograft models, BYON3521 showed significant antitumor activity upon single-dose administration in multiple non-MET-amplified tumor types with low, moderate, and high MET expression, including complete tumor remissions in models with moderate MET expression. In the repeat-dose Good Laboratory Practice (GLP) safety assessment in cynomolgus monkeys, BYON3521 was well tolerated and based on the observed toxicities and their reversibility, the highest non-severely toxic dose was set at 15 mg/kg. A human pharmacokinetics (PK) model was derived from the PK data from the cynomolgus safety assessments, and the minimal efficacious dose in humans is estimated to be in the range of 3 to 4 mg/kg. In all, our nonclinical data suggests that BYON3521 is a safe ADC with potential for clinical benefit in patients. A first-in-human dose-escalation study is currently ongoing to determine the maximum tolerated dose and recommended dose for expansion (NCT05323045).


Subject(s)
Antibodies, Monoclonal , Immunoconjugates , Animals , Humans , Mice , Antibodies, Monoclonal, Humanized , Cell Line, Tumor , Immunoglobulin G , Xenograft Model Antitumor Assays
2.
Thyroid ; 33(6): 732-742, 2023 06.
Article in English | MEDLINE | ID: mdl-37016815

ABSTRACT

Background: Treatment of Graves' hyperthyroidism (GH) and Graves' orbitopathy (GO) is far from adequate, and hence, new substances that specifically target the autoantigens in GH/GO are warranted. This study determined the preclinical in vitro efficacy of SYD5115, a novel low-molecular-weight compound that inhibits the thyrotropin receptor (TSH-R). Methods: The TSH-R inhibiting capability of SYD5115 was tested through stimulation of wild-type and chimeric TSH-R expressed in Chinese hamster ovary (CHO) cells using two functional (stimulatory and blocking) cell-based TSH-R-Ab bioassays. TSH-R expressing human orbital fibroblasts, collected from GH+GO patients (GOF), were stimulated with the monoclonal antibody M22 or with stimulatory TSH-R-Ab (TSAb)-positive sera with cyclic adenosine monophosphate (cAMP) or hyaluronic acid (HA) release as readouts. The effect of SYD5115 on the viability of GOF was tested in 4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide and scratch cell growth assays. Results: SYD5115 significantly and dose dependently inhibited the TSH-R activation through M22 or TSAb-positive sera in all performed bioassays. Inhibition showed similar levels in the TSAb reporter bioassay and in the cAMP assay with GOF. The % inhibition and compound concentration showed a sigmoidal relationship, with all seven TSAb-positive sera markedly inhibited by SYD5115. An SYD5115 dose-dependent inhibition of M22 (10 ng/mL, 6 hours)-stimulated HA and/or cAMP-release from GOF was observed. Strong SYD5115-induced inhibitions of M22-stimulated cAMP production in GOF were registered with SYD5115 concentrations of 1 (p = 0.0029), 10 (p < 0.0001), 100 (p < 0.0001), 1,000 (p < 0.0001), and 10,000 (p < 0.0001) nM, respectively. SYD5115-induced inhibition of M22-stimulated HA production was noted with SYD5115 concentrations of 100 (p = 0.0392), 1000 (p = 0.0431), and 10,000 (p = 0.0245) nM, respectively. The inhibitory activity of SYD5115 was confirmed in a human osteosarcoma U2OS cell line stably expressing human TSH-R with cAMP as readout. SYD5115 induced 100% inhibition of the M22-induced cAMP levels with a potency of 193 nM. Compared with control, SYD5115 did neither impact the growth nor the migration of cultivated GOF. In addition, SYD5115 did not alter the viability of GOF. Conclusions: SYD5115 blocked M22- and TSAb-induced TSH-R activity with a nanomolar potency in TSH-R-overexpressed CHO cells as well as primary GOF, which demonstrates the ability of this small molecule to block TSH-R overactivity.


Subject(s)
Graves Ophthalmopathy , Receptors, Thyrotropin , Cricetinae , Animals , Humans , Graves Ophthalmopathy/drug therapy , Cricetulus , CHO Cells , Immunoglobulins, Thyroid-Stimulating , Thyrotropin/metabolism , Autoantibodies
3.
J Immunother Cancer ; 11(4)2023 04.
Article in English | MEDLINE | ID: mdl-37068796

ABSTRACT

BACKGROUND: Preclinical studies have firmly established the CD47-signal-regulatory protein (SIRP)α axis as a myeloid immune checkpoint in cancer, and this is corroborated by available evidence from the first clinical studies with CD47 blockers. However, CD47 is ubiquitously expressed and mediates functional interactions with other ligands as well, and therefore targeting of the primarily myeloid cell-restricted inhibitory immunoreceptor SIRPα may represent a better strategy. METHOD: We generated BYON4228, a novel SIRPα-directed antibody. An extensive preclinical characterization was performed, including direct comparisons to previously reported anti-SIRPα antibodies. RESULTS: BYON4228 is an antibody directed against SIRPα that recognizes both allelic variants of SIRPα in the human population, thereby maximizing its potential clinical applicability. Notably, BYON4228 does not recognize the closely related T-cell expressed SIRPγ that mediates interactions with CD47 as well, which are known to be instrumental in T-cell extravasation and activation. BYON4228 binds to the N-terminal Ig-like domain of SIRPα and its epitope largely overlaps with the CD47-binding site. BYON4228 blocks binding of CD47 to SIRPα and inhibits signaling through the CD47-SIRPα axis. Functional studies show that BYON4228 potentiates macrophage-mediated and neutrophil-mediated killing of hematologic and solid cancer cells in vitro in the presence of a variety of tumor-targeting antibodies, including trastuzumab, rituximab, daratumumab and cetuximab. The silenced Fc region of BYON4228 precludes immune cell-mediated elimination of SIRPα-positive myeloid cells, implying anticipated preservation of myeloid immune effector cells in patients. The unique profile of BYON4228 clearly distinguishes it from previously reported antibodies representative of agents in clinical development, which either lack recognition of one of the two SIRPα polymorphic variants (HEFLB), or cross-react with SIRPγ and inhibit CD47-SIRPγ interactions (SIRPAB-11-K322A, 1H9), and/or have functional Fc regions thereby displaying myeloid cell depletion activity (SIRPAB-11-K322A). In vivo, BYON4228 increases the antitumor activity of rituximab in a B-cell Raji xenograft model in human SIRPαBIT transgenic mice. Finally, BYON4228 shows a favorable safety profile in cynomolgus monkeys. CONCLUSIONS: Collectively, this defines BYON4228 as a preclinically highly differentiating pan-allelic SIRPα antibody without T-cell SIRPγ recognition that promotes the destruction of antibody-opsonized cancer cells. Clinical studies are planned to start in 2023.


Subject(s)
CD47 Antigen , Neoplasms , Mice , Animals , Humans , T-Lymphocytes/metabolism , Rituximab , Macrophages , Neoplasms/drug therapy , Antibodies, Neoplasm
4.
Bioorg Med Chem ; 84: 117258, 2023 04 15.
Article in English | MEDLINE | ID: mdl-37001244

ABSTRACT

The thyrotropin receptor (TSH-R) regulates the thyroid gland and is normally activated by thyrotropin. In patients with Graves' disease, TSH-R is also stimulated by stimulatory TSH-R autoantibodies leading to hyperthyroidism. In this paper, we describe the discovery of SYD5115 (67), a novel small molecule TSH-R antagonist with nanomolar potency. SYD5115 also blocks stimulating antibody induced synthesis of the thyroid hormone thyroxine (T4) in vivo, after a single oral dose. During optimization, several issues had to be addressed such as the low metabolic stability and the potential mutagenicity of our first series of compounds.


Subject(s)
Graves Disease , Receptors, Thyrotropin , Humans , Autoantibodies , Graves Disease/drug therapy , Receptors, G-Protein-Coupled , Receptors, Thyrotropin/antagonists & inhibitors , Thyrotropin/metabolism
5.
Biomed Pharmacother ; 136: 111123, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33486211

ABSTRACT

Cancer is one of the main causes of death in the world and thus a global public health problem. Among the treatments available for cancer are surgery, radiotherapy, and chemotherapy. Currently, there is increased interest in the combination of two or more antitumor agents to achieve a synergistic effect in cancer therapy. Doxorubicin (DOX), a chemotherapeutic which has a potent antineoplastic action, has been used in the treatment of various tumors. However, the use of DOX is limited, mainly due to the cardiotoxicity. Therefore, nanostructured systems, such as liposomes, have been developed to carry this drug and target the tumor region, since tumor tissues present enhanced permeability and retention for nanosystems. Cardiac glycosides, such as digitoxin, have recently shown great antitumor potential despite the low therapeutic index which may limit their use. Furthermore, some compounds of this class have low water solubility, which makes their in vivo administration difficult. In this context, liposomes represent a valid strategy to carry simultaneously antitumor drugs allowing their intravenous administration. In this study, liposomes loaded with glucoevatromonoside containing peracetylated glucose hydroxyl groups (GEVPG) and DOX at molar ratio of 1:1 (SpHL-GEVPG:DOX 1:1) were developed, and their chemical and physicochemical properties were evaluated. This formulation presented a combination index (CI) lower than 1 at inhibitory concentration of 90 % growth (IC90) for three human breast tumor lines evaluated (0.52 ± 0.39 for MDA-MB-231, 0.19 ± 0.13 for MCF-7, and 0.99 ± 0.09 for SKBR-3). These results indicate a synergistic cytotoxic effect of the GEVPG and DOX combination encapsulated in liposomes. In addition, SpHL-GEVPG:DOX 1:1 presented selectivity towards these cancer cells. Long-term in vitro cytotoxicity studies demonstrated that MDA-MB-231 surviving cells after treatment with SpHL-GEVPG:DOX 1:1 did not recover proliferation capacity after 21 d. From the studies of cell cycle and death pathway evaluation, it was observed that SpHL-GEVPG:DOX 1:1 arrested the cell cycle in the G2/M phase and similarly induced apoptosis and necrosis. However, SpHL-GEVPG:DOX at molar ratio of 1:1 showed lower induction of both apoptotic and necrotic pathways compared to free DOX and SpHL-DOX, suggesting that the mechanism of death involved may not be related to necrosis or apoptosis. Lastly, SpHL-GEVPG:DOX 1:1 showed a good storage stability for 90 d at 4 °C. Therefore, the results of the present work indicate the potential use of SpHL-GEVPG:DOX 1:1 as a new anticancer formulation.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/pharmacology , Breast Neoplasms/drug therapy , Cardenolides/pharmacology , Doxorubicin/pharmacology , Lipids/chemistry , Antineoplastic Combined Chemotherapy Protocols/chemistry , Apoptosis/drug effects , Breast Neoplasms/pathology , Cardenolides/chemistry , Cell Proliferation/drug effects , Cell Survival/drug effects , Dose-Response Relationship, Drug , Doxorubicin/chemistry , Drug Compounding , Drug Synergism , Female , Humans , Liposomes , MCF-7 Cells , Necrosis , Time Factors
6.
Bioconjug Chem ; 31(9): 2136-2146, 2020 09 16.
Article in English | MEDLINE | ID: mdl-32697078

ABSTRACT

Engineering cysteines at specific sites in antibodies to create well-defined ADCs for the treatment of cancer is a promising approach to increase the therapeutic index and helps to streamline the manufacturing process. Here, we report the development of an in silico screening procedure to select for optimal sites in an antibody to which a hydrophobic linker-drug can be conjugated. Sites were identified inside the cavity that is naturally present in the Fab part of the antibody. Conjugating a linker-drug to these sites demonstrated the ability of the antibody to shield the hydrophobic character of the linker-drug while resulting ADCs maintained their cytotoxic potency in vitro. Comparison of site-specific ADCs versus randomly conjugated ADCs in an in vivo xenograft model revealed improved efficacy and exposure. We also report a selective reducing agent that is able to reduce the engineered cysteines while leaving the interchain disulfides in the oxidized state. This enables us to manufacture site-specific ADCs without introducing impurities associated with the conventional reduction/oxidation procedure for site-specific conjugation.


Subject(s)
Antibiotics, Antineoplastic/chemistry , Cysteine/chemistry , Duocarmycins/analogs & derivatives , Immunoconjugates/chemistry , Animals , Antibiotics, Antineoplastic/therapeutic use , Cell Line, Tumor , Duocarmycins/therapeutic use , Humans , Hydrophobic and Hydrophilic Interactions , Immunoconjugates/therapeutic use , Immunoglobulin G/chemistry , Immunoglobulin G/therapeutic use , Mice , Models, Molecular , Neoplasms/drug therapy , Oxidation-Reduction
7.
J Neuroimmunol ; 345: 577268, 2020 08 15.
Article in English | MEDLINE | ID: mdl-32480242

ABSTRACT

We report six patients with anti-LGI1 associated epilepsy. Two patients presented with new-onset generalized tonic-clonic seizures, four developed faciobrachial dystonic seizures and two piloerection. All patients had significant cognitive complaints at the time of diagnosis. All patients described seizure reduction during the first week of carbamazepine, and seizure freedom was obtained at a median of 13 days (range 7-22), sustained after the initiation of immunosuppression. Median time from symptom onset to carbamazepine initiation was 164 days (range 38-206 days). We discuss the particular seizure response to sodium channel blocking antiepileptic drugs, alone or associated with immunosuppression in this antibody mediated seizures.


Subject(s)
Ambulatory Care/methods , Anticonvulsants/therapeutic use , Autoantibodies/blood , Epilepsy/blood , Epilepsy/drug therapy , Intracellular Signaling Peptides and Proteins/blood , Adult , Aged , Carbamazepine/therapeutic use , Epilepsy/diagnostic imaging , Female , Humans , Male , Middle Aged , Outpatients , Prospective Studies , Treatment Outcome
8.
Osteoporos Int ; 31(5): 905-912, 2020 May.
Article in English | MEDLINE | ID: mdl-31897546

ABSTRACT

The congenital adrenal hyperplasia population seems to have an intrinsic tendency to a high frequency of low bone mass. However in this single-center and long-term evaluated cohort, the simplified corticoid regimen, with exclusive dexamethasone single dose reposition during adulthood, did not represent a risk factor for decrease in bone health. INTRODUCTION: The impact of long-term and supposedly physiological doses of gluco and mineralocorticoid (GC/MC) on bone mineral density (BMD) in congenital adrenal hyperplasia (CAH) remains discordant among studies, which contain different clinical forms and corticoid regimens. Our aim was to evaluate the BMD in CAH adults receiving similar GC regimen since childhood and to correlate it with GC/MC cumulative doses. METHODS: Only patients with good compliance, who used cortisone acetate (CA) during childhood and dexamethasone after the final height achievement. Cumulative GC/MC doses were calculated from diagnosis until last evaluation. BMD was analyzed by the first and last energy X-ray absorptiometry (DXA) scans performed. RESULTS: Twenty simple virilizing (SV) and 14 salt wasting (WS) whose mean age was 26 ± 6 years, mean CA, dexamethasone, and fludrocortisone cumulative doses were 63,813 ± 32,767, 812 ± 558, and 319 ± 325 mg/m2, respectively. Based on the last DXA, low BMD was observed in 11% of patients, total hip Z-score was lower in the SW than SV form (p = 0.04). Cumulative CA dose had an inverse correlation with femoral neck Z-score (p < 0.01). Total cumulative GC and MC doses had an inverse correlation with total hip Z-score (p < 0.01). In the analysis of sequential BMD during dexamethasone therapy, no association was observed among cumulative GC/MC doses, clinical forms, sex, and lumbar Z-score delta. CONCLUSIONS: Even though a low CA regimen during growth periods in addition to MC replacement appears to have an influence on BMD at femoral sites, interestingly a low dexamethasone one does not seem to be deleterious for bone health in adulthood.


Subject(s)
Adrenal Hyperplasia, Congenital , Bone Density , Absorptiometry, Photon , Adrenal Hyperplasia, Congenital/drug therapy , Adult , Child , Glucocorticoids/adverse effects , Humans , Retrospective Studies , Young Adult
9.
Braz J Med Biol Res ; 51(11): e7653, 2018 Oct 04.
Article in English | MEDLINE | ID: mdl-30304132

ABSTRACT

This study aimed to explore attentional patterns among children with inattentive attention-deficit/hyperactivity disorder (ADHD-I) and children with typical development (TD), using a latent class analysis (LCA). Patterns of brain connectivity were also explored. The sample comprised 29 ADHD-I and 29 TD matched children. An LCA was conducted to reclassify subjects according to their attentional performance, considering cognitive measures of attention and behavioral symptoms, regardless of group of origin. The new clusters were then compared in respect to brain white matter measurements (extracted from diffusion tensor imaging). Participants were rearranged in 2 new latent classes, according to their performance in an attention task and the results of behavioral scales, resulting in groups with more homogeneous attentional profiles. A comparison of the 2 new classes using the white matter measurements revealed increased fractional anisotropy in the left inferior fronto-occipital fasciculus and left inferior longitudinal fasciculus for the class composed by participants with a higher risk of attentional problems. The findings indicated that it was possible to observe variability regarding neuropsychological profile, accompanied by underpinning neurobiological differences, even among individuals with the same disorder subtype - inattentive ADHD. This specific data-driven clustering analysis may help to enhance understanding of the pathophysiology of the disorder's phenotypes.


Subject(s)
Attention Deficit Disorder with Hyperactivity/physiopathology , Attention/physiology , White Matter/physiopathology , Adolescent , Anisotropy , Attention Deficit Disorder with Hyperactivity/diagnosis , Case-Control Studies , Child , Cognition/physiology , Diffusion Tensor Imaging/methods , Female , Humans , Male , Neuropsychological Tests , Reaction Time/physiology , Reference Standards , Reference Values , Statistics as Topic/methods , White Matter/diagnostic imaging
10.
Mol Cancer Ther ; 17(11): 2389-2398, 2018 11.
Article in English | MEDLINE | ID: mdl-30093567

ABSTRACT

Carboxylesterase 1c (CES1c) is responsible for linker-drug instability and poor pharmacokinetics (PK) of several antibody-drug conjugates (ADC) in mice, but not in monkeys or humans. Preclinical development of these ADCs could be improved if the PK in mice would more closely resemble that of humans and is not affected by an enzyme that is irrelevant for humans. SYD985, a HER2-targeting ADC based on trastuzumab and linker-drug vc-seco-DUBA, is also sensitive to CES1c. In the present studies, we first focused on the interaction between CES1c and SYD985 by size- exclusion chromatography, Western blotting, and LC/MS-MS analysis, using recombinant CES1c and plasma samples. Intriguingly, CES1c activity not only results in release of the active toxin DUBA but also in formation of a covalent bond between CES1c and the linker of vc-seco-DUBA. Mass spectrometric studies enabled identification of the CES1c cleavage site on the linker-drug and the structure of the CES1c adduct. To assess the in vivo impact, CES1c-/- SCID mice were generated that showed stable PK for SYD985, comparable to that in monkeys and humans. Patient-derived xenograft (PDX) studies in these mice showed enhanced efficacy compared with PDX studies in CES1c+/+ mice and provided a more accurate prediction of clinical efficacy of SYD985, hence delivering better quality data. It seems reasonable to assume that CES1c-/- SCID mice can increase quality in ADC development much broader for all ADCs that carry linker-drugs susceptible to CES1c, without the need of chemically modifying the linker-drug to specifically increase PK in mice. Mol Cancer Ther; 17(11); 2389-98. ©2018 AACR.


Subject(s)
Carboxylesterase/deficiency , Immunoconjugates/pharmacology , Immunoconjugates/pharmacokinetics , Animals , Carboxylesterase/metabolism , Catalytic Domain , Cell Line, Tumor , Female , Humans , Immunoconjugates/chemistry , Mice, Knockout , Mice, SCID , Peptides/chemistry , Rats, Wistar , Trastuzumab/chemistry , Treatment Outcome
11.
Amino Acids ; 50(5): 503-511, 2018 May.
Article in English | MEDLINE | ID: mdl-29305745

ABSTRACT

The biomembrane natural (NRL-Natural Rubber Latex), manipulated from the latex obtained from the rubber tree Hevea brasiliensis, has shown great potential for application in biomedicine and biomaterials. Reflecting the biocompatibility and low bounce rate of this material, NRL has been used as a physical barrier to infectious agents and for the controlled release of drugs and extracts. The aim of the present study was to evaluate the incorporation and release of peptides using a latex biomembrane carrier. After incorporation, the release of material from the membrane was observed using spectrophotometry. Analyses using HPLC and mass spectroscopy did not confirm the release of the antimicrobial peptide [W6]Hylin a1 after 24 h. In addition, analysis of the release solution showed new compounds, indicating the degradation of the peptide by enzymes contained in the latex. Additionally, the release of a peptide with a shorter sequence (Ac-WAAAA) was evaluated, and degradation was not observed. These results showed that the use of NRL as solid matrices as delivery systems of peptide are sequence dependent and could to be evaluated for each sequence.


Subject(s)
Drug Carriers , Hevea/chemistry , Membranes, Artificial , Peptides , Drug Carriers/chemistry , Drug Carriers/pharmacokinetics , Drug Carriers/pharmacology , Drug Evaluation, Preclinical , Latex , Peptides/chemistry , Peptides/pharmacokinetics , Peptides/pharmacology
12.
Braz. j. med. biol. res ; 51(11): e7653, 2018. tab, graf
Article in English | LILACS | ID: biblio-951724

ABSTRACT

This study aimed to explore attentional patterns among children with inattentive attention-deficit/hyperactivity disorder (ADHD-I) and children with typical development (TD), using a latent class analysis (LCA). Patterns of brain connectivity were also explored. The sample comprised 29 ADHD-I and 29 TD matched children. An LCA was conducted to reclassify subjects according to their attentional performance, considering cognitive measures of attention and behavioral symptoms, regardless of group of origin. The new clusters were then compared in respect to brain white matter measurements (extracted from diffusion tensor imaging). Participants were rearranged in 2 new latent classes, according to their performance in an attention task and the results of behavioral scales, resulting in groups with more homogeneous attentional profiles. A comparison of the 2 new classes using the white matter measurements revealed increased fractional anisotropy in the left inferior fronto-occipital fasciculus and left inferior longitudinal fasciculus for the class composed by participants with a higher risk of attentional problems. The findings indicated that it was possible to observe variability regarding neuropsychological profile, accompanied by underpinning neurobiological differences, even among individuals with the same disorder subtype - inattentive ADHD. This specific data-driven clustering analysis may help to enhance understanding of the pathophysiology of the disorder's phenotypes.


Subject(s)
Humans , Male , Female , Child , Adolescent , Attention/physiology , Attention Deficit Disorder with Hyperactivity/physiopathology , White Matter/physiopathology , Reaction Time/physiology , Reference Standards , Reference Values , Attention Deficit Disorder with Hyperactivity/diagnosis , Case-Control Studies , Statistics as Topic/methods , Anisotropy , Cognition/physiology , Diffusion Tensor Imaging/methods , White Matter/diagnostic imaging , Neuropsychological Tests
13.
J Biomater Sci Polym Ed ; 28(18): 2117-2130, 2017 Dec.
Article in English | MEDLINE | ID: mdl-28875763

ABSTRACT

Natural rubber latex biomedical (NRLb) obtained from the rubber tree Hevea brasiliensis has shown great potential in biomedicine and biomaterial applications. NRLb has been utilized as a physical barrier against infectious agents and in the controlled release of drugs and extracts. In the present work, NRLb was polymerized in a lyophilizer using different volumes of water to control the resultant membrane porosity and characterized regarding the surface morphology, water vapour permeability (WVP), mechanical properties, haemolytic activity and cytotoxicity. The release of bovine serum albumin protein from the latex membranes was evaluated. Drug release rates increased with porosity and membranes were able to control protein release up to 12 h. In addition, WVP increased with the quantity of pores. The cell viability observed for the porous membrane was higher than that noted for conventional membranes. In summary, the porosity control of natural latex membranes can be used to modulate properties and make them suitable for biomedical applications, such as wound dressings, modulated gas-exchange membranes and controlled drug delivery systems.


Subject(s)
Biocompatible Materials/chemistry , Drug Carriers/chemistry , Drug Liberation , Hevea/chemistry , Latex/chemistry , 3T3 Cells , Animals , Hemolysis/drug effects , Mechanical Phenomena , Mice , Permeability , Porosity , Steam
14.
J Pharm Sci ; 106(11): 3378-3384, 2017 11.
Article in English | MEDLINE | ID: mdl-28755925

ABSTRACT

The release of drugs from poly(lactic-co-glycolic acid) (PLGA) microparticles depends to a large extent on the porosity of the particles. Therefore, porosity determination of PLGA microparticles is extremely important during pharmaceutical product development. Currently, mercury intrusion porosimetry (MIP) is widely used despite its disadvantages, such as the need for a large amount of sample (several hundreds of milligrams) and residual toxic waste. Here, we present a method based on the estimation of the volume of a known mass (a few milligrams) of particles using micro-flow imaging (MFI) to determine microparticle batch porosity. Factors that are critical for the accuracy of this method (i.e., density of the suspending fluid, particle concentration, and postsample rinsing) were identified and measures were taken to minimize potential errors. The validity of the optimized method was confirmed by using nonporous polymethylmethacrylate microparticles. Finally, the method was employed for the analysis of 7 different PLGA microparticle batches with various porosities (4.0%-51.9%) and drug loadings (0%-38%). Obtained porosity values were in excellent agreement with the MIP-derived porosities. Altogether, the developed MFI-based method is a valuable tool for deriving the total volume of a known mass of PLGA particles and therewith their porosity.


Subject(s)
Delayed-Action Preparations/chemistry , Lactic Acid/chemistry , Polyglycolic Acid/chemistry , Injections , Microscopy/methods , Particle Size , Polylactic Acid-Polyglycolic Acid Copolymer , Porosity
15.
Eur J Pharm Biopharm ; 117: 91-104, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28392414

ABSTRACT

The purpose of this study was to explore the potential of flow imaging microscopy to measure particle size and agglomeration of poly(lactic-co-glycolic acid) (PLGA) microparticles. The particle size distribution of pharmaceutical PLGA microparticle products is routinely determined with laser diffraction. In our study, we performed a unique side-by-side comparison between MFI 5100 (flow imaging microscopy) and Mastersizer 2000 (laser diffraction) for the particle size analysis of two commercial PLGA microparticle products, i.e., Risperdal Consta and Sandostatin LAR. Both techniques gave similar results regarding the number and volume percentage of the main particle population (28-220µm for Risperdal Consta; 16-124µm for Sandostatin LAR). MFI additionally detected a 'fines' population (<28µm for Risperdal Consta; <16µm for Sandostatin LAR), which was overlooked by Mastersizer. Moreover, MFI was able to split the main population into 'monospheres' and 'agglomerates' based on particle morphology, and count the number of particles in each sub-population. Finally, we presented how MFI can be applied in process development of risperidone PLGA microparticles and to monitor the physical stability of Sandostatin LAR. These case studies showed that MFI provides insight into the effect of different process steps on the number, size and morphology of fines, monospheres and agglomerates as well as the extent of microparticle agglomeration after reconstitution. This can be particularly important for the suspendability, injectability and release kinetics of PLGA microparticles.


Subject(s)
Image Processing, Computer-Assisted/methods , Lactic Acid/chemistry , Microspheres , Particle Size , Polyglycolic Acid/chemistry , Lactic Acid/analysis , Polyglycolic Acid/analysis , Polylactic Acid-Polyglycolic Acid Copolymer
16.
Mol Cancer Ther ; 15(8): 1900-9, 2016 08.
Article in English | MEDLINE | ID: mdl-27256376

ABSTRACT

Uterine serous carcinoma (USC) is an aggressive form of endometrial cancer. Up to 35% of USC may overexpress the HER2/neu oncogene at strong (i.e., 3+) levels by IHC while an additional 40% to 50% express HER2/neu at moderate (2+) or low (1+) levels. We investigated the efficacy of SYD985, (Synthon Biopharmaceuticals), a novel HER2-targeting antibody-drug conjugate (ADC) composed of the mAb trastuzumab linked to a highly potent DNA-alkylating agent (i.e., duocarmycin) in USC. We also compared the antitumor activity of SYD985 in head-to-head experiments to trastuzumab emtansine (T-DM1), a FDA-approved ADC, against multiple primary USC cell lines expressing different levels of HER2/neu in in vitro and in vivo experiments. Using antibody-dependent cellular cytotoxicity (ADCC), proliferation, viability, and bystander killing assays as well as propidium iodide-based flow cytometry assays and multiple in vivo USC mouse xenograft models, we demonstrate for the first time that SYD985 is a novel ADC with activity against USC with strong (3+) as well as low to moderate (i.e., 1+/2+) HER2/neu expression. SYD985 is 10- to 70-fold more potent than T-DM1 in comparative experiments and, unlike T-DM1, it is active against USC demonstrating moderate/low or heterogeneous HER2/neu expression. Clinical studies with SYD985 in patients harboring chemotherapy-resistant USC with low, moderate, and high HER2 expression are warranted. Mol Cancer Ther; 15(8); 1900-9. ©2016 AACR.


Subject(s)
Antineoplastic Agents/pharmacology , Cystadenocarcinoma, Serous/genetics , Gene Expression , Immunoconjugates/pharmacology , Indoles , Receptor, ErbB-2/antagonists & inhibitors , Uterine Neoplasms/genetics , Adult , Aged , Aged, 80 and over , Animals , Antibody-Dependent Cell Cytotoxicity/immunology , Antineoplastic Agents/chemistry , Bystander Effect , Cathepsin B/genetics , Cathepsin B/metabolism , Cell Line, Tumor , Cell Survival/drug effects , Class I Phosphatidylinositol 3-Kinases , Cystadenocarcinoma, Serous/drug therapy , Cystadenocarcinoma, Serous/metabolism , Cystadenocarcinoma, Serous/pathology , Disease Models, Animal , Duocarmycins , Female , Humans , Immunoconjugates/chemistry , Indoles/chemistry , Mice , Middle Aged , Mutation , Phosphatidylinositol 3-Kinases/genetics , Phosphatidylinositol 3-Kinases/metabolism , Pyrrolidinones/chemistry , Survival Analysis , Uterine Neoplasms/drug therapy , Uterine Neoplasms/metabolism , Uterine Neoplasms/pathology , Xenograft Model Antitumor Assays
17.
Mol Pharm ; 12(6): 1813-35, 2015 Jun 01.
Article in English | MEDLINE | ID: mdl-25635711

ABSTRACT

Antibody-drug conjugates (ADCs) that are currently on the market or in clinical trials are predominantly based on two drug classes: auristatins and maytansinoids. Both are tubulin binders and block the cell in its progression through mitosis. We set out to develop a new class of linker-drugs based on duocarmycins, potent DNA-alkylating agents that are composed of a DNA-alkylating and a DNA-binding moiety and that bind into the minor groove of DNA. Linker-drugs were evaluated as ADCs by conjugation to the anti-HER2 antibody trastuzumab via reduced interchain disulfides. Duocarmycin 3b, bearing an imidazo[1,2-a]pyridine-based DNA-binding unit, was selected as the drug moiety, notably because of its rapid degradation in plasma. The drug was incorporated into the linker-drugs in its inactive prodrug form, seco-duocarmycin 3a. Linker attachment to the hydroxyl group in the DNA-alkylating moiety was favored over linking to the DNA-binding moiety, as the first approach gave more consistent results for in vitro cytotoxicity and generated ADCs with excellent human plasma stability. Linker-drug 2 was eventually selected based on the properties of the corresponding trastuzumab conjugate, SYD983, which had an average drug-to-antibody ratio (DAR) of about 2. SYD983 showed subnanomolar potencies against multiple human cancer cell lines, was highly efficacious in a BT-474 xenograft model, and had a long half-life in cynomolgus monkeys, in line with high stability in monkey and human plasma. Studies comparing ADCs with a different average DAR showed that a higher average DAR leads to increased efficacy but also to somewhat less favorable physicochemical and toxicological properties. Fractionation of SYD983 with hydrophobic interaction chromatography resulted in SYD985, consisting of about 95% DAR2 and DAR4 species in an approximate 2:1 ratio and having an average DAR of about 2.8. SYD985 combines several favorable properties from the unfractionated ADCs with an improved homogeneity. It was selected for further development and recently entered clinical Phase I evaluation.


Subject(s)
Immunoconjugates/chemistry , Indoles/chemistry , Receptor, ErbB-2/metabolism , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacokinetics , Cell Line, Tumor , Duocarmycins , Humans , Immunoconjugates/pharmacokinetics , Pyrrolidinones/chemistry
18.
Mol Cancer Ther ; 14(3): 692-703, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25589493

ABSTRACT

SYD985 is a HER2-targeting antibody-drug conjugate (ADC) based on trastuzumab and vc-seco-DUBA, a cleavable linker-duocarmycin payload. To evaluate the therapeutic potential of this new ADC, mechanistic in vitro studies and in vivo patient-derived xenograft (PDX) studies were conducted to compare SYD985 head-to-head with T-DM1 (Kadcyla), another trastuzumab-based ADC. SYD985 and T-DM1 had similar binding affinities to HER2 and showed similar internalization. In vitro cytotoxicity assays showed similar potencies and efficacies in HER2 3+ cell lines, but in cell lines with low HER2 expression, SYD985 was 3- to 50-fold more potent than T-DM1. In contrast with T-DM1, SYD985 efficiently induced bystander killing in vitro in HER2-negative (HER2 0) cells mixed with HER2 3+, 2+, or 1+ cell lines. At pH conditions relevant for tumors, cathepsin-B cleavage studies showed efficient release of the active toxin by SYD985 but not by T-DM1. These in vitro data suggest that SYD985 might be a more potent ADC in HER2-expressing tumors in vivo, especially in low HER2-expressing and/or in heterogeneous tumors. In line with this, in vivo antitumor studies in breast cancer PDX models showed that SYD985 is very active in HER2 3+, 2+, and 1+ models, whereas T-DM1 only showed significant antitumor activity in HER2 3+ breast cancer PDX models. These properties of SYD985 may enable expansion of the target population to patients who have low HER2-expressing breast cancer, a patient population with still unmet high medical need.


Subject(s)
Antibodies, Monoclonal/pharmacology , Breast Neoplasms/drug therapy , Breast Neoplasms/genetics , Indoles/pharmacology , Receptor, ErbB-2/genetics , Animals , Cell Line, Tumor , Duocarmycins , Female , Humans , Mice , Mice, Nude , Pyrrolidinones/pharmacology , Trastuzumab/pharmacology , Xenograft Model Antitumor Assays/methods
19.
J Immunol ; 192(8): 3908-3914, 2014 Apr 15.
Article in English | MEDLINE | ID: mdl-24639348

ABSTRACT

Chemokines comprise a family of secreted proteins that activate G protein-coupled chemokine receptors and thereby control the migration of leukocytes during inflammation or immune surveillance. The positional information required for such migratory behavior is governed by the binding of chemokines to membrane-tethered glycosaminoglycans (GAGs), which establishes a chemokine concentration gradient. An often observed but incompletely understood behavior of chemokines is the ability of unrelated chemokines to enhance the potency with which another chemokine subtype can activate its cognate receptor. This phenomenon has been demonstrated to occur between many chemokine combinations and across several model systems and has been dubbed chemokine cooperativity. In this study, we have used GAG binding-deficient chemokine mutants and cell-based functional (migration) assays to demonstrate that chemokine cooperativity is caused by competitive binding of chemokines to GAGs. This mechanistic explanation of chemokine cooperativity provides insight into chemokine gradient formation in the context of inflammation, in which multiple chemokines are secreted simultaneously.


Subject(s)
Chemokines/metabolism , Glycosaminoglycans/metabolism , Animals , Binding, Competitive , CHO Cells , Chemokine CCL19/metabolism , Chemokine CCL21/metabolism , Chemokine CXCL13/metabolism , Chemokines/chemistry , Chemotaxis , Cricetinae , Cricetulus , Models, Biological , Protein Binding , Protein Multimerization , Receptors, Chemokine/metabolism
20.
N Z Vet J ; 62(1): 15-20, 2014 Jan.
Article in English | MEDLINE | ID: mdl-23869425

ABSTRACT

AIM: To compare five different protocols for estimating the lactate minimum speed (LMS) with that for estimating the maximal lactate steady state (MLSS) in Arabian horses, in order to obtain a more rapid method for monitoring aerobic capacity and prescribing training schedules. METHODS: Eight purebred Arabian horses were conditioned to exercise on a treadmill for 12 days then submitted to three to five exercise sessions to determine the MLSS. Blood samples were collected from a jugular catheter at specific intervals for measurement of lactate concentrations. The MLSS was the velocity maintained during the last 20 minutes of constant submaximal exercise, at which the concentration of lactate increased by no more than 1.0 mmol/L. The LMS test protocols (P1 - P5) included a warm-up period followed by a high-intensity gallop. The speed was then reduced to 4 m/s, and the incremental portion of the test was initiated. In P1, P2, and P3, the velocity increment was 0.5 m/s, and the duration of each incremental stage was three, five and seven minutes, respectively. In P4 and P5, the velocity increments were 1.0 and 1.5 m/s, respectively, and the duration of the stages was fixed at five minutes each. A second-degree polynomial function was fitted to the lactate-velocity curve, and the velocity corresponding to the lowest concentration of lactate was the LMS. RESULTS: Only the mean LMS determined by P1 and P2 did not differ from the velocity determined by the MLSS test (p > 0.1). There was a strong correlation (r >0.6) between P1 and the MLSS velocity. A limits of agreement plot revealed that the best agreement occurred between the MLSS test and P1 (mean bias = 0.14 m/s), followed by P2 (bias = -0.22 m/s). The lactate concentrations associated with the various LMS protocols did not differ. CONCLUSIONS: This study shows the variation between protocols of the LMS test for determining the onset of blood lactate accumulation but also reveals that, at least for Arabian horses, the P1 protocol of the LMS has good agreement with the MLSS.


Subject(s)
Horses/blood , Horses/physiology , Lactic Acid/blood , Muscle, Skeletal/physiology , Physical Conditioning, Animal/physiology , Animals , Female , Horses/genetics , Male
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