RESUMO
The maytansinoid antibody-drug conjugates (ADCs) in clinical development for cancer therapy each contain a derivative of the microtubule-targeting agent, maytansine, covalently attached to the antibody via an engineered linker. A sample of any of these conjugates contains molecules with different numbers of maytansinoid molecules, or "drug" loads, the relative abundance of which can be determined by mass spectrometry. We examined the accuracy of the Poisson distribution and the binomial distribution in predicting the relative abundance of species with different drug loads for three antibody-maytansinoid conjugates with different antibodies and linker-maytansinoid pairings. We used variance, calculated from the experimental mass distribution data, as the parameter to determine the optimal value n of the binomial distribution number of trials. The accuracy of the Poisson distribution in predicting distribution of the species abundance in these conjugates varied among the conjugates. In contrast, the accuracy of the binomial distribution was similar for all three conjugates and comparable to the best accuracy of the Poisson distribution, as supported by a paired t-test.
Assuntos
Imunoconjugados/farmacocinética , Maitansina/química , Anticorpos Monoclonais Humanizados/química , Anticorpos Monoclonais Humanizados/farmacocinética , Humanos , Imunoconjugados/química , Espectrometria de Massas , Modelos EstatísticosRESUMO
Replication of human cytomegalovirus (CMV) requires the expression of the viral mitochondria-localized inhibitor of apoptosis (vMIA). vMIA inhibits apoptosis by recruiting Bax to mitochondria, resulting in its neutralization. We show that vMIA decreases cell size, reduces actin polymerization, and induces cell rounding. As compared with vMIA-expressing CMV, vMIA-deficient CMV, which replicates in fibroblasts expressing the adenoviral apoptosis suppressor E1B19K, induces less cytopathic effects. These vMIA effects can be separated from its cell death-inhibitory function because vMIA modulates cellular morphology in Bax-deficient cells. Expression of vMIA coincided with a reduction in the cellular adenosine triphosphate (ATP) level. vMIA selectively inhibited one component of the ATP synthasome, namely, the mitochondrial phosphate carrier. Exposure of cells to inhibitors of oxidative phosphorylation produced similar effects, such as an ATP level reduced by 30%, smaller cell size, and deficient actin polymerization. Similarly, knockdown of the phosphate carrier reduced cell size. Our data suggest that the cytopathic effect of CMV can be explained by vMIA effects on mitochondrial bioenergetics.
Assuntos
Apoptose , Infecções por Citomegalovirus/metabolismo , Citomegalovirus/fisiologia , Proteínas Imediatamente Precoces/fisiologia , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Proteínas Virais/fisiologia , Actinas/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Apoptose/efeitos dos fármacos , Citomegalovirus/genética , Efeito Citopatogênico Viral , Inibidores Enzimáticos/farmacologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/patologia , Fibroblastos/virologia , Células HeLa , Humanos , Proteínas Imediatamente Precoces/genética , Proteínas Imediatamente Precoces/toxicidade , Camundongos , Proteínas Mitocondriais/genética , Células NIH 3T3 , Fosforilação Oxidativa/efeitos dos fármacos , Polímeros/metabolismo , Proteínas Virais/genética , Proteínas Virais/toxicidade , Proteína X Associada a bcl-2/antagonistas & inibidores , Proteína X Associada a bcl-2/genéticaRESUMO
Apoptosis is a major problem in animal cell cultures during production of biopharmaceuticals, such as recombinant proteins or viral vectors. A 293 cell line constitutively expressing vMIA (viral mitochondria-localized inhibitor of apoptosis) was constructed and examined on production of a model recombinant protein, green fluorescent protein (GFP) in the adenovirus-293 expression system, and on production of a model infectious adenoviral vector. vMIA-293 cells were more resistant than the parental 293 cells to apoptosis induced by either oxidative stress, or by adenovirus infection. The yield of GFP produced in vMIA-293 cell cultures was consistently higher (approximately 140%) compared to that in the parental cells. vMIA reduced production of adenovirus infectious particles, which was not due to a decline of adenovirus replication, since adenoviral DNA replication rate in vMIA-293 cells was higher than that in the parental cells. In conclusion, introduction of the vMIA gene into the 293 cell line is a promising strategy to improve recombinant protein production in the adenovirus-293 expression system.
Assuntos
Adenoviridae/genética , Proteínas Mitocondriais/genética , Proteínas Recombinantes/biossíntese , Proteínas Virais/genética , Adenoviridae/metabolismo , Apoptose , Morte Celular , Células Cultivadas , Citometria de Fluxo , Proteínas de Fluorescência Verde/biossíntese , Proteínas de Fluorescência Verde/genética , Microscopia de Fluorescência , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Estresse Oxidativo , Proteínas Recombinantes/genética , Transfecção , Proteínas Virais/metabolismoRESUMO
EC131, a new folate receptor (FR)-targeted drug conjugate, was prepared by covalently attaching the vitamin folic acid (FA) to a potent microtubule-inhibiting agent, maytansinoid DM1, via an intramolecular disulfide bond. When tested on cells in culture, EC131 was found to retain high affinity for FR-positive cells and to provide FR-specific cytotoxicity with an IC(50) in the low nanomolar range. The activity of EC131 was completely blocked in the presence of an excess of free FA, and no activity was detected against FR-negative cells. When evaluated against s.c. FR-positive M109 tumors in BALB/c mice, EC131 showed marked antitumor efficacy. Furthermore, this therapeutic effect occurred in the apparent absence of weight loss or noticeable organ tissue degeneration. In contrast, no significant antitumor activity was observed in EC131-treated animals that were codosed with an excess of FA, thus demonstrating the targeted specificity of the in vivo activity. EC131 also showed marked antitumor activity against FR-positive human KB tumors, but not against FR-negative A549 tumors, in nude mice with no evidence of systemic toxicity during or after the therapy. In contrast, therapy with the free maytansinoid drug (in the form of DM1-S-Me) proved not to be effective against the KB model when administered at its maximum tolerated dose (MTD). Taken together, these results indicate that EC131 is a highly potent agent capable of producing therapeutic benefit in murine tumor models at sub-MTD levels.
Assuntos
Antineoplásicos/farmacologia , Proteínas de Transporte/metabolismo , Ácido Fólico/farmacologia , Maitansina/farmacologia , Extratos Vegetais/farmacologia , Receptores de Superfície Celular/metabolismo , Animais , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Receptores de Folato com Âncoras de GPI , Ácido Fólico/química , Ácido Fólico/metabolismo , Humanos , Células KB , Dose Máxima Tolerável , Maitansina/química , Maytenus/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Transplante de NeoplasiasRESUMO
Apoptosis is increasingly implicated as an early line of defense against viral infections. Viruses have devised numerous strategies to delay apoptosis of infected cells. Many viruses encode cell death suppressors that target mitochondrial apoptotic signaling pathway, indicating the importance of this pathway in the anti-viral response. Human and primate cytomegaloviruses encode the viral mitochondria-localized inhibitor of apoptosis vMIA, but no overt homologue of vMIA was identified in any non-primate cytomegalovirus. Here we report that m38.5 protein encoded by murine cytomegalovirus, which is unrelated to vMIA in its amino acid sequence, delays death receptor ligation-induced cell death, and that m38.5 associates with Bax, recruits it to mitochondria, and blocks Bax-mediated but not Bak-mediated mitochondrial outer membrane permeabilization. Thus, primate and murine cytomegaloviruses have evolved non-homologous but functionally similar cell death suppressors selectively targeting the Bax-mediated branch of the mitochondrial apoptotic signaling pathway, indicating the importance of this branch in the response of diverse host organisms against cytomegalovirus infections.
Assuntos
Membranas Mitocondriais/metabolismo , Muromegalovirus/metabolismo , Proteínas Virais/metabolismo , Proteína X Associada a bcl-2/metabolismo , Animais , Morte Celular , Células HCT116 , Células HeLa , Humanos , Camundongos , Permeabilidade , Ligação Proteica , Conformação Proteica , Transporte Proteico , RNA Interferente Pequeno/metabolismo , Receptores de Morte Celular/metabolismo , Proteína X Associada a bcl-2/química , Receptor fas/metabolismoRESUMO
Conjugates of the anti-CanAg humanized monoclonal antibody huC242 with the microtubule-formation inhibitor DM1 (a maytansinoid), or with the DNA alkylator DC1 (a CC1065 analogue), have been evaluated for their ability to eradicate mixed cell populations formed from CanAg-positive and CanAg-negative cells in culture and in xenograft tumors in mice. We found that in culture, conjugates of either drug killed not only the target antigen-positive cells but also the neighboring antigen-negative cells. Furthermore, we showed that, in vivo, these conjugates were effective in eradicating tumors containing both antigen-positive and antigen-negative cells. The presence of antigen-positive cells was required for this killing of bystander cells. This target cell-activated killing of bystander cells was dependent on the nature of the linker between the antibody and the drug. Conjugates linked via a reducible disulfide bond were capable of exerting the bystander effect whereas equally potent conjugates linked via a nonreducible thioether bond were not. Our data offer a rationale for developing optimally constructed antibody-drug conjugates for treating tumors that express the target antigen either in a homogeneous or heterogeneous manner.
Assuntos
Neoplasias do Colo/tratamento farmacológico , Imunoconjugados/farmacologia , Maitansina/análogos & derivados , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/farmacologia , Antígenos de Neoplasias/imunologia , Linhagem Celular Tumoral , Neoplasias do Colo/imunologia , Reagentes de Ligações Cruzadas/química , Feminino , Células HT29 , Humanos , Imunoconjugados/química , Imunoconjugados/imunologia , Maitansina/química , Maitansina/farmacologia , Camundongos , Camundongos SCID , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Antibody-drug conjugates are targeted anticancer agents consisting of a cytotoxic drug covalently linked to a monoclonal antibody for tumor antigen-specific activity. Once bound to the target cell-surface antigen, the conjugate must be processed to release an active form of the drug, which can reach its intracellular target. Here, we used both biological and biochemical methods to better define this process for antibody-maytansinoid conjugates. In particular, we examined the metabolic fate in cells of huC242-maytansinoid conjugates containing either a disulfide linker (huC242-SPDB-DM4) or a thioether linker (huC242-SMCC-DM1). Using cell cycle analysis combined with lysosomal inhibitors, we showed that lysosomal processing is required for the activity of antibody-maytansinoid conjugates, irrespective of the linker. We also identified and characterized the released maytansinoid molecules from these conjugates, and measured their rate of release compared with the kinetics of cell cycle arrest. Both conjugates are efficiently degraded in lysosomes to yield metabolites consisting of the intact maytansinoid drug and linker attached to lysine. The lysine adduct is the sole metabolite from the thioether-linked conjugate. However, the lysine metabolite generated from the disulfide-linked conjugate is reduced and S-methylated to yield the lipophilic and potently cytotoxic metabolite, S-methyl-DM4. These findings provide insight into the mechanism of action of antibody-maytansinoid conjugates in general, and more specifically, identify a biochemical mechanism that may account for the significantly enhanced antitumor efficacy observed with disulfide-linked conjugates.
Assuntos
Antineoplásicos Fitogênicos/farmacocinética , Neoplasias do Colo/tratamento farmacológico , Imunotoxinas/farmacocinética , Maitansina/análogos & derivados , Animais , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Ciclo Celular/efeitos dos fármacos , Neoplasias do Colo/imunologia , Neoplasias do Colo/metabolismo , Reagentes de Ligações Cruzadas/química , Reagentes de Ligações Cruzadas/farmacocinética , Reagentes de Ligações Cruzadas/farmacologia , Dissulfetos/química , Dissulfetos/farmacocinética , Dissulfetos/farmacologia , Células HT29 , Humanos , Imunotoxinas/química , Imunotoxinas/farmacologia , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Maitansina/química , Maitansina/farmacocinética , Camundongos , Camundongos SCID , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The outlook for patients with refractory/relapsed acute myeloid leukemia (AML) remains poor, with conventional chemotherapeutic treatments often associated with unacceptable toxicities, including severe infections due to profound myelosuppression. Thus there exists an urgent need for more effective agents to treat AML that confer high therapeutic indices and favorable tolerability profiles. Because of its high expression on leukemic blast and stem cells compared with normal hematopoietic stem cells and progenitors, CD123 has emerged as a rational candidate for molecularly targeted therapeutic approaches in this disease. Here we describe the development and preclinical characterization of a CD123-targeting antibody-drug conjugate (ADC), IMGN632, that comprises a novel humanized anti-CD123 antibody G4723A linked to a recently reported DNA mono-alkylating payload of the indolinobenzodiazepine pseudodimer (IGN) class of cytotoxic compounds. The activity of IMGN632 was compared with X-ADC, the ADC utilizing the G4723A antibody linked to a DNA crosslinking IGN payload. With low picomolar potency, both ADCs reduced viability in AML cell lines and patient-derived samples in culture, irrespective of their multidrug resistance or disease status. However, X-ADC exposure was >40-fold more cytotoxic to the normal myeloid progenitors than IMGN632. Of particular note, IMGN632 demonstrated potent activity in all AML samples at concentrations well below levels that impacted normal bone marrow progenitors, suggesting the potential for efficacy in AML patients in the absence of or with limited myelosuppression. Furthermore, IMGN632 demonstrated robust antitumor efficacy in multiple AML xenograft models. Overall, these findings identify IMGN632 as a promising candidate for evaluation as a novel therapy in AML.
Assuntos
Imunoconjugados/uso terapêutico , Subunidade alfa de Receptor de Interleucina-3/imunologia , Leucemia Mieloide Aguda/tratamento farmacológico , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Células-Tronco Hematopoéticas/efeitos dos fármacos , Xenoenxertos , Humanos , Imunoconjugados/imunologia , Camundongos , Células-Tronco Neoplásicas/efeitos dos fármacos , Células Tumorais CultivadasRESUMO
Antibody-drug conjugates (ADCs) are designed to specifically bind to and kill cells expressing their target antigens. In addition to the obvious requirement of the presence of the target antigen on the cell surface, several other factors contribute to the sensitivity of target cells to the action of ADCs. These include (i) the rate of internalization of the ADC, (ii) its proteolytic degradation in late endosomes and lysosomes and the subsequent release of cytotoxic drug, and (iii) the intracellular concentration of the released drug. In addition to killing antigen-expressing cells, some ADCs were found to kill bystander cells irrespective of their antigen expression. This review summarizes the current knowledge of the mechanisms of killing of antigen-expressing and bystander cells by antibody-drug conjugates.
Assuntos
Anticorpos Monoclonais/farmacologia , Citotoxicidade Celular Dependente de Anticorpos , Antineoplásicos/farmacologia , Imunoconjugados/farmacologia , Neoplasias/imunologia , Anticorpos Monoclonais/metabolismo , Antígenos de Neoplasias/metabolismo , Antineoplásicos/metabolismo , Humanos , Imunoconjugados/metabolismoRESUMO
Maytansine, a highly cytotoxic natural product, failed as an anticancer agent in human clinical trials because of unacceptable systemic toxicity. The potent cell killing ability of maytansine can be used in a targeted delivery approach for the selective destruction of cancer cells. A series of new maytansinoids, bearing a disulfide or thiol substituent were synthesized. The chain length of the ester side chain and the degree of steric hindrance on the carbon atom bearing the thiol substituent were varied. Several of these maytansinoids were found to be even more potent in vitro than maytansine. The targeted delivery of these maytansinoids, using monoclonal antibodies, resulted in a high, specific killing of the targeted cells in vitro and remarkable antitumor activity in vivo.
Assuntos
Antineoplásicos/síntese química , Maitansina/análogos & derivados , Maitansina/síntese química , Animais , Anticorpos Monoclonais/química , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Dissulfetos/síntese química , Dissulfetos/química , Dissulfetos/farmacologia , Portadores de Fármacos , Sistemas de Liberação de Medicamentos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Maitansina/química , Maitansina/farmacologia , Camundongos , Camundongos SCID , Transplante de Neoplasias , Relação Estrutura-Atividade , Compostos de Sulfidrila/síntese química , Compostos de Sulfidrila/química , Compostos de Sulfidrila/farmacologia , Transplante HeterólogoRESUMO
The microtubule-targeting maytansinoids accumulate in cells and induce mitotic arrest at 250- to 1000-fold lower concentrations than those required for their association with tubulin or microtubules. To identify the mechanisms of this intracellular accumulation and exceptional cytotoxicity of maytansinoids we studied interaction of a highly cytotoxic maytansinoid, S-methyl DM1 and several other maytansinoids with cells. S-methyl DM1 accumulated inside the cells with a markedly higher apparent affinity than to tubulin or microtubules. The apparent affinities of maytansinoids correlated with their cytotoxicities. The number of intracellular binding sites for S-methyl DM1 in MCF7 cells was comparable to the number of tubulin molecules per cell (~ 4-6 × 10(7) copies). Efflux of 3[H]-S-methyl DM1 from cells was enhanced in the presence of an excess of non-labeled S-methyl DM1, indicating that re-binding of 3 [H]-S-methyl DM1 to intracellular binding sites contributed to its intracellular retention. Liposomes loaded with non-polymerized tubulin recapitulated the apparent high-affinity association of S-methyl DM1 to cells. We propose a model for the intracellular accumulation of maytansinoids in which molecules of the compounds diffuse into a cell and associate with tubulin. Affinities of maytansinoids for individual tubulin molecules are weak, but the high intracellular concentration of tubulin favors, after dissociation of a compound-tubulin complex, their re-binding to a tubulin molecule, or to a tip of a microtubule in the same cell, over their efflux. As a result, a significant fraction of microtubule tips is occupied with a maytansinoid when added to cells at sub-nanomolar concentrations, inducing mitotic arrest and cell death.
Assuntos
Maitansina/metabolismo , Tubulina (Proteína)/metabolismo , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Humanos , Lipossomos , Maitansina/farmacologia , Microtúbulos/efeitos dos fármacos , Microtúbulos/metabolismo , Modelos Biológicos , Ligação ProteicaRESUMO
A majority of ovarian and non-small cell lung adenocarcinoma cancers overexpress folate receptor α (FRα). Here, we report the development of an anti-FRα antibody-drug conjugate (ADC), consisting of a FRα-binding antibody attached to a highly potent maytansinoid that induces cell-cycle arrest and cell death by targeting microtubules. From screening a large panel of anti-FRα monoclonal antibodies, we selected the humanized antibody M9346A as the best antibody for targeted delivery of a maytansinoid payload into FRα-positive cells. We compared M9346A conjugates with various linker/maytansinoid combinations, and found that a conjugate, now denoted as IMGN853, with the N-succinimidyl 4-(2-pyridyldithio)-2-sulfobutanoate (sulfo-SPDB) linker and N(2')-deacetyl-N(2')-(4-mercapto-4-methyl-1-oxopentyl)-maytansine (DM4) exhibited the most potent antitumor activity in several FRα-expressing xenograft tumor models. The level of expression of FRα on the surface of cells was a major determinant in the sensitivity of tumor cells to the cytotoxic effect of the conjugate. Efficacy studies of IMGN853 in xenografts of ovarian cancer and non-small cell lung cancer cell lines and of a patient tumor-derived xenograft model demonstrated that the ADC was highly active against tumors that expressed FRα at levels similar to those found on a large fraction of ovarian and non-small cell lung cancer patient tumors, as assessed by immunohistochemistry. IMGN853 displayed cytotoxic activity against FRα-negative cells situated near FRα-positive cells (bystander cytotoxic activity), indicating its ability to eradicate tumors with heterogeneous expression of FRα. Together, these findings support the clinical development of IMGN853 as a novel targeted therapy for patients with FRα-expressing tumors.
Assuntos
Anticorpos Monoclonais/farmacologia , Receptor 1 de Folato/antagonistas & inibidores , Imunoconjugados/farmacologia , Neoplasias/tratamento farmacológico , Ensaios Antitumorais Modelo de Xenoenxerto , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais Humanizados/imunologia , Anticorpos Monoclonais Humanizados/farmacologia , Efeito Espectador/efeitos dos fármacos , Linhagem Celular Tumoral , Citotoxicidade Imunológica/efeitos dos fármacos , Feminino , Receptor 1 de Folato/imunologia , Humanos , Imunoconjugados/imunologia , Maitansina/análogos & derivados , Maitansina/imunologia , Maitansina/farmacologia , Camundongos Nus , Camundongos SCID , Terapia de Alvo Molecular/métodos , Neoplasias/imunologia , Neoplasias/metabolismo , Resultado do Tratamento , Carga Tumoral/efeitos dos fármacos , Carga Tumoral/imunologiaRESUMO
Human cytomegalovirus encodes a powerful cell death suppressor vMIA (viral mitochondria-localized inhibitor of apoptosis), also known as pUL37x1. vMIA, a product of the immediate early gene UL37 exon 1, is predominantly localized in mitochondria, where it appears to form a complex with adenine nucleotide translocator, believed to be a component of the mitochondrial transition pore complex. vMIA suppresses apoptosis by blocking permeabilization of the mitochondrial outer membrane. Expression of vMIA protects cells against apoptosis triggered by diverse stimuli, including ligation of death receptors, exposure to certain cytotoxic drugs, and infection with an adenovirus mutant deficient in E1B19K. Deletion mutagenesis of vMIA revealed two domains that are necessary and, together, sufficient for its anti-apoptotic activity. The first domain contains a mitochondrial targeting signal. The function of the second domain is still unknown. vMIA does not share any significant amino acid sequence homology with Bcl-2, and, unlike Bcl-2 or Bcl-x(L), it does not bind BAX or VDAC. These structural and functional differences between vMIA and Bcl-2 suggest that vMIA represents a separate class of cell death suppressors. Experiments with vMIA-deficient CMV (human cytomegalovirus) mutants provide strong evidence that the anti-apoptotic function of vMIA is required to prevent CMV-induced apoptosis, and is necessary for viral replication. In addition to vMIA, UL37 encodes two longer splice-variant proteins, gpUL37 and GP37(M). Biological functions of these proteins have not yet been identified, and may be unrelated to their anti-apoptotic activity. The identification of vMIA and the finding that its anti-apoptotic function is required for CMV replication provides a rationale for the development of anti-CMV pharmaceuticals that would inactivate vMIA and thus restore apoptosis in cells infected with CMV.
Assuntos
Apoptose/fisiologia , Infecções por Citomegalovirus/terapia , Citomegalovirus/fisiologia , Proteínas Imediatamente Precoces/fisiologia , Membranas Intracelulares/metabolismo , Mitocôndrias/fisiologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Virais , Animais , Humanos , Proteínas Mitocondriais/metabolismo , Replicação ViralRESUMO
To develop effective taxane-antibody immunoconjugates, we have prepared a series of modified taxanes that have both improved toxicity and solubility in aqueous systems as compared to paclitaxel (1a). These taxanes have been modified at either the C-10 or C-7 position and were found to be very cytotoxic against both normal and multi-drug-resistant (MDR) cells, as well as up to 30 times more soluble than paclitaxel in various buffer systems.
Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Paclitaxel/análogos & derivados , Taxoides/química , Taxoides/farmacologia , Antineoplásicos/administração & dosagem , Bioquímica/métodos , Neoplasias da Mama/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Dissulfetos/química , Portadores de Fármacos , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Paclitaxel/química , Paclitaxel/farmacologia , Polietilenoglicóis/química , Solubilidade , Relação Estrutura-Atividade , Taxoides/administração & dosagem , Células Tumorais CultivadasRESUMO
Taxoids bearing methyldisulfanyl(alkanoyl) groups for taxoid-antibody immunoconjugates were designed, synthesized and their activities evaluated. A highly cytotoxic C-10 methyldisulfanylpropanoyl taxoid was conjugated to monoclonal antibodies recognizing the epidermal growth factor receptor (EGFR) expressed in human squamous cancers. These conjugates were shown to possess remarkable target-specific antitumor activity in vivo against EGFR-expressing A431 tumor xenografts in severe combined immune deficiency mice, resulting in complete inhibition of tumor growth in all the treated mice.
Assuntos
Anticorpos Monoclonais/química , Antineoplásicos/síntese química , Imunoconjugados/química , Paclitaxel/análogos & derivados , Paclitaxel/química , Pró-Fármacos/síntese química , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Receptores ErbB/imunologia , Humanos , Imunoconjugados/farmacologia , Camundongos , Camundongos SCID , Pró-Fármacos/química , Pró-Fármacos/farmacologia , Relação Estrutura-Atividade , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
PURPOSE: The CD38 cell surface antigen is expressed in diverse hematologic malignancies including multiple myeloma, B-cell non-Hodgkin lymphoma (NHL), B-cell chronic lymphocytic leukemia, B-cell acute lymphoblastic leukemia (ALL), and T-cell ALL. Here, we assessed the antitumor activity of the anti-CD38 antibody SAR650984. EXPERIMENTAL DESIGN: Activity of SAR650984 was examined on lymphoma, leukemia and multiple myeloma cell lines, primary multiple myeloma samples, and multiple myeloma xenograft models in immunodeficient mice. RESULTS: We identified a humanized anti-CD38 antibody with strong proapoptotic activity independent of cross-linking agents, and potent effector functions including complement-dependent cytotoxicity, antibody-dependent cell-mediated cytotoxicity, and antibody-dependent cellular phagocytosis (ADCP), equivalent in vitro to rituximab in CD20+ and CD38+ models. This unique antibody, termed SAR650984, inhibited the ADP-ribosyl cyclase activity of CD38, likely through an allosteric antagonism as suggested by 3D structure analysis of the complex. In vivo, SAR650984 was active in diverse NHL, ALL, and multiple myeloma CD38+ tumor xenograft models. SAR650984 demonstrated single-agent activity comparable with rituximab or cyclophosphamide in Daudi or SU-DHL-8 lymphoma xenograft models with induction of the proapoptotic marker cleaved capase-7. In addition, SAR650984 had more potent antitumor activity than bortezomib in NCI-H929 and Molp-8 multiple myeloma xenograft studies. Consistent with its mode of action, SAR650984 demonstrated potent proapoptotic activity against CD38+ human primary multiple myeloma cells. CONCLUSION: These results validate CD38 as a therapeutic target and support the current evaluation of this unique CD38-targeting functional antibody in phase I clinical trials in patients with CD38+ B-cell malignancies.
Assuntos
ADP-Ribosil Ciclase 1/genética , Anticorpos Monoclonais Humanizados/administração & dosagem , Neoplasias Hematológicas/tratamento farmacológico , Linfoma de Células B/tratamento farmacológico , Glicoproteínas de Membrana/genética , Mieloma Múltiplo/tratamento farmacológico , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/efeitos adversos , Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Murinos/administração & dosagem , Citotoxicidade Celular Dependente de Anticorpos/efeitos dos fármacos , Linhagem Celular Tumoral , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Neoplasias Hematológicas/patologia , Humanos , Linfoma de Células B/genética , Linfoma de Células B/patologia , Camundongos , Mieloma Múltiplo/patologia , Rituximab , Ensaios Antitumorais Modelo de XenoenxertoAssuntos
Anticorpos Monoclonais/farmacologia , Antineoplásicos/farmacologia , Antígeno CD56/imunologia , Linfoma Extranodal de Células T-NK/patologia , Ado-Trastuzumab Emtansina , Anticorpos Monoclonais Humanizados , Divisão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Maitansina/análogos & derivados , Trastuzumab , Células Tumorais CultivadasRESUMO
There are considerable differences in tumour biology between adult and paediatric cancers. The existence of cancer initiating cells/cancer stem cells (CIC/CSC) in paediatric solid tumours is currently unclear. Here, we show the successful propagation of primary human Wilms' tumour (WT), a common paediatric renal malignancy, in immunodeficient mice, demonstrating the presence of a population of highly proliferative CIC/CSCs capable of serial xenograft initiation. Cell sorting and limiting dilution transplantation analysis of xenograft cells identified WT CSCs that harbour a primitive undifferentiated-NCAM1 expressing-"blastema" phenotype, including a capacity to expand and differentiate into the mature renal-like cell types observed in the primary tumour. WT CSCs, which can be further enriched by aldehyde dehydrogenase activity, overexpressed renal stemness and genes linked to poor patient prognosis, showed preferential protein expression of phosphorylated PKB/Akt and strong reduction of the miR-200 family. Complete eradication of WT in multiple xenograft models was achieved with a human NCAM antibody drug conjugate. The existence of CIC/CSCs in WT provides new therapeutic targets.
Assuntos
Neoplasias Renais/metabolismo , Neoplasias Renais/patologia , Células-Tronco Neoplásicas/patologia , Tumor de Wilms/metabolismo , Tumor de Wilms/patologia , Antígeno AC133 , Aldeído Desidrogenase/metabolismo , Família Aldeído Desidrogenase 1 , Animais , Anticorpos Monoclonais/uso terapêutico , Antígenos CD/metabolismo , Antígeno CD56/metabolismo , Diferenciação Celular , Proliferação de Células , Separação Celular/métodos , Expressão Gênica , Glicoproteínas/metabolismo , Humanos , Neoplasias Renais/genética , Neoplasias Renais/terapia , Maitansina/análogos & derivados , Maitansina/uso terapêutico , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Células-Tronco Neoplásicas/metabolismo , Peptídeos/metabolismo , Retinal Desidrogenase , Células Tumorais Cultivadas , Ensaio Tumoral de Célula-Tronco , Tumor de Wilms/genética , Tumor de Wilms/terapia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The synthesis and biological evaluation of phosphate prodrugs of analogues of 1 (CC-1065) and their conjugates with antibodies are described. The phosphate group on the 1,2,9,9a-tetrahydrocyclopropa[c]benz[e]indol-4-one (CBI) portion of the compounds confers enhanced solubility and stability in aqueous solutions. In the presence of phosphatases, these compounds convert into active DNA-alkylating agents. The synthesis of the prodrugs was achieved sequentially through coupling of CBI with a bis-indolyl moiety, followed by attachment of a thiol-containing linker, and conversion of the hydroxyl group of CBI into a phosphate prodrug. The linkers incorporated into the prodrugs enable conjugation to an antibody via either a stable disulfide or thioether bond, in aqueous buffer solutions containing as little as 5% organic cosolvent, resulting in exclusively monomeric and stable antibody-cytotoxic prodrug conjugates. Two disulfide-containing linkers differing in the degree of steric hindrance were used in antibody conjugates to test the effect of different rates of intracellular disulfide cleavage and effector release on biological activity. The prodrugs can be converted to the active cytotoxic compounds through the action of endogenous phosphatases. Antibody-prodrug conjugates displayed potent antigen-selective cytotoxic activity in vitro and antitumor activity in vivo.
Assuntos
Anticorpos Monoclonais Humanizados/química , Antineoplásicos Alquilantes/síntese química , Indóis/síntese química , Compostos Organofosforados/síntese química , Pró-Fármacos/síntese química , Animais , Antineoplásicos Alquilantes/química , Antineoplásicos Alquilantes/farmacologia , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Estabilidade de Medicamentos , Duocarmicinas , Feminino , Humanos , Indóis/química , Indóis/farmacologia , Camundongos , Camundongos SCID , Transplante de Neoplasias , Compostos Organofosforados/química , Compostos Organofosforados/farmacologia , Pró-Fármacos/química , Pró-Fármacos/farmacologia , Solubilidade , Estereoisomerismo , Relação Estrutura-Atividade , Transplante HeterólogoRESUMO
One approach to improving activity of anticancer drugs is to conjugate them to antibodies that recognize tumor-associated, cell-surface antigens. The antibody-drug conjugate concept evolved following major advances, first, in the development of humanized and fully human antibodies; second, in the discoveries of highly cytotoxic compounds ('drugs) linkable to antibodies; and finally, in the optimization of linkers that couple the drug to the antibody and provide sufficient stability of the antibody-drug conjugate in the circulation, optimal activation of the drug in the tumor, and the ability of the activated drug to overcome multidrug resistance. In this article, we will review the considerations for selecting a target antigen, the design of the conjugate, and the pre-clinical and clinical experiences with the current generation of antibody-drug conjugates.