RESUMO
Purpose: Steroidal androgens suppress androgen receptor and estrogen receptor positive (AR/ER+) breast cancer cells and were used to treat breast cancer, eliciting favorable response. The current study evaluates the activity and efficacy of the oral selective AR modulator RAD140 in in vivo and in vitro models of AR/ER+ breast cancer.Experimental Design: A series of in vitro assays were used to determine the affinity of RAD140 to 4 nuclear receptors and evaluate its tissue-selective AR activity. The efficacy and pharmacodynamics of RAD140 as monotherapy or in combination with palbociclib were evaluated in AR/ER+ breast cancer xenograft models.Results: RAD140 bound AR with high affinity and specificity and activated AR in breast cancer but not prostate cancer cells. Oral administration of RAD140 substantially inhibited the growth of AR/ER+ breast cancer patient-derived xenografts (PDX). Activation of AR and suppression of ER pathway, including the ESR1 gene, were seen with RAD140 treatment. Coadministration of RAD140 and palbociclib showed improved efficacy in the AR/ER+ PDX models. In line with efficacy, a subset of AR-repressed genes associated with DNA replication was suppressed with RAD140 treatment, an effect apparently enhanced by concurrent administration of palbociclib.Conclusions: RAD140 is a potent AR agonist in breast cancer cells with a distinct mechanism of action, including the AR-mediated repression of ESR1 It inhibits the growth of multiple AR/ER+ breast cancer PDX models as a single agent, and in combination with palbociclib. The preclinical data presented here support further clinical investigation of RAD140 in AR/ER+ breast cancer patients. Clin Cancer Res; 23(24); 7608-20. ©2017 AACR.
Assuntos
Androgênios/farmacologia , Neoplasias da Mama/tratamento farmacológico , Proliferação de Células/efeitos dos fármacos , Nitrilas/farmacologia , Oxidiazóis/farmacologia , Receptores Androgênicos/metabolismo , Androgênios/uso terapêutico , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Receptor alfa de Estrogênio/genética , Receptor alfa de Estrogênio/metabolismo , Estrogênios , Feminino , Humanos , Células MCF-7 , Camundongos , Nitrilas/uso terapêutico , Oxidiazóis/uso terapêutico , Receptores Androgênicos/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Purpose: Estrogen receptor-positive (ER+) breast cancers are typically treated with endocrine agents, and dependence on the ER pathway is often retained even after multiple rounds of antiestrogen therapy. Selective estrogen receptor degraders (SERD) are being developed as a strategy to more effectively target ER and exploit ER dependence in these cancers, which includes inhibiting both wild-type and mutant forms of ER. The purpose of this study was to evaluate the efficacy of a novel orally bioavailable SERD, elacestrant (RAD1901), in preclinical models of ER+ breast cancer.Experimental Design: Elacestrant was evaluated as a single agent and in combination with palbociclib or everolimus in multiple ER+ breast cancer models, including several patient-derived xenograft models.Results: Elacestrant induces the degradation of ER, inhibits ER-mediated signaling and growth of ER+ breast cancer cell lines in vitro and in vivo, and significantly inhibits tumor growth of multiple PDX models. Furthermore, we demonstrate that elacestrant in combination with palbociclib or everolimus can lead to greater efficacy in certain contexts. Finally, elacestrant exhibits significant antitumor activity both as a single agent and in combination with palbociclib in two patient-derived breast cancer xenograft models harboring ESR1 mutations.Conclusions: These data underscore the potential clinical utility of elacestrant as a single agent and as a combination therapy, for both early- and late-stage ER+ disease. Clin Cancer Res; 23(16); 4793-804. ©2017 AACR.
Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Tetra-Hidronaftalenos/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Everolimo/administração & dosagem , Feminino , Humanos , Células MCF-7 , Camundongos Endogâmicos BALB C , Camundongos Nus , Piperazinas/administração & dosagem , Piridinas/administração & dosagem , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Moduladores Seletivos de Receptor Estrogênico/administração & dosagem , Moduladores Seletivos de Receptor Estrogênico/farmacologia , Tetra-Hidronaftalenos/administração & dosagem , Carga Tumoral/efeitos dos fármacosRESUMO
Tropomyosin-related kinases (Trk) are tyrosine kinase receptors implicated in tumor proliferation, invasion, and survival signaling across a number of tumors, making them potentially attractive targets for the treatment of cancer. AZD7451 is a potent and selective inhibitor of Trk kinases currently undergoing a Phase I dose escalation in glioblastoma multiforme at the National Cancer Institute. A key part of early clinical testing for AZD7451 involves demonstrating that pharmacokinetic half-life and clinical exposures of AZD7451 are sufficient to inhibit Trk receptors in preclinical models. To address this need, an ultra sensitive analytical method was developed to measure the AZD7451 profile in human plasma. A liquid-liquid extraction recovered >80% of AZD7451 before quantitative analysis by ultra HPLC-MS/MS. A Varian Polaris(®) C18-A column and a mass transition of m/z 383.5â340.5 (m/z 389.6â342.0 for the internal standard [(2)H6]-AZD7451) was used, and a dynamic calibration range of 0.5-1000ng/mL was established, which provided a sensitive (<8.5% deviation), and precise (<6%) quantitative assay for AZD7451. AZD7451 demonstrated stability in human plasma at room temperature for 24h (<7% change) and after extraction at 4°C for 24h (<8% change), and was stable through 4 freeze/thaw cycles (<8% change). This method was used to measure AZD7451 plasma levels in clinical samples to confirm the sensitivity at several time points following AZD7451 treatment in subjects with glioblastoma.
Assuntos
2-Aminopurina/sangue , Antineoplásicos/sangue , Cromatografia Líquida de Alta Pressão/métodos , Inibidores de Proteínas Quinases/sangue , Pirazóis/sangue , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Espectrometria de Massas em Tandem/métodos , 2-Aminopurina/química , Antineoplásicos/química , Antineoplásicos/farmacocinética , Estabilidade de Medicamentos , Humanos , Modelos Lineares , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacocinética , Pirazóis/química , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
PURPOSE: The Hedgehog (Hh) pathway has emerged as an important pathway in multiple tumor types and is thought to be dependent on a paracrine signaling mechanism. The purpose of this study was to determine the role of pancreatic cancer-associated fibroblasts (human pancreatic stellate cells, HPSCs) in Hh signaling. In addition, we evaluated the efficacy of a novel Hh antagonist, AZD8542, on tumor progression with an emphasis on the role of the stroma compartment. EXPERIMENTAL DESIGN: Expression of Hh pathway members and activation of the Hh pathway were analyzed in both HPSCs and pancreatic cancer cells. We tested the effects of Smoothened (SMO) inhibition with AZD8542 on tumor growth in vivo using an orthotopic model of pancreatic cancer containing varying amounts of stroma. RESULTS: HPSCs expressed high levels of SMO receptor and low levels of Hh ligands, whereas cancer cells showed the converse expression pattern. HPSC proliferation was stimulated by Sonic Hedgehog with upregulation of downstream GLI1 mRNA. These effects were abrogated by AZD8542 treatment. In an orthotopic model of pancreatic cancer, AZD8542 inhibited tumor growth only when HPSCs were present, implicating a paracrine signaling mechanism dependent on stroma. Further evidence of paracrine signaling of the Hh pathway in prostate and colon cancer models is provided, demonstrating the broader applicability of our findings. CONCLUSION: Based on the use of our novel human-derived pancreatic cancer stellate cells, our results suggest that Hh-targeted therapies primarily affect the tumor-associated stroma, rather than the epithelial compartment.
Assuntos
Adenocarcinoma/tratamento farmacológico , Antineoplásicos/farmacologia , Benzamidas/farmacologia , Proteínas Hedgehog/antagonistas & inibidores , Imidazóis/farmacologia , Neoplasias Pancreáticas/tratamento farmacológico , Comunicação Parácrina/efeitos dos fármacos , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Animais , Antineoplásicos/química , Benzamidas/química , Linhagem Celular Tumoral , Neoplasias do Colo/tratamento farmacológico , Modelos Animais de Doenças , Feminino , Fibroblastos/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Imidazóis/química , Neoplasias Hepáticas/tratamento farmacológico , Masculino , Camundongos , Camundongos Nus , Metástase Neoplásica , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Células Estreladas do Pâncreas/fisiologia , Neoplasias da Próstata/tratamento farmacológico , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Receptor Smoothened , Regulação para CimaRESUMO
Neuroblastoma is a common pediatric tumor characterized by clinical heterogeneity. Because it is derived from sympathetic neuroblasts, the NTRK family of neurotrophin receptors plays an integral role in neuroblastoma cell survival, growth, and differentiation. Indeed, high expression of NTRK1 is associated with favorable clinical features and outcome, whereas expression of NTRK2 and its ligand, brain-derived neurotrophic factor (BDNF), are associated with unfavorable features and outcome. AZ64 (Astra Zeneca) is a potent and selective inhibitor of the NTRK tyrosine kinases that blocks phosphorylation at nanomolar concentrations. To determine the preclinical activity of AZ64, we performed intervention trials in a xenograft model with NTRK2-overexpressing neuroblastomas. AZ64 alone significantly inhibited tumor growth compared to vehicle-treated animals (p = 0.0006 for tumor size). Furthermore, the combination of AZ64 with conventional chemotherapeutic agents, irinotecan and temozolomide (irino-temo), showed significantly enhanced anti-tumor efficacy compared to irino-temo alone [(p < 0.0001 for tumor size, p < 0.0005 for event-free survival (EFS)]. We also assessed the combination of AZ64 and local radiation therapy (RT) on a neuroblastoma hindlimb xenograft model, and the efficacy of local RT was significantly increased when animals were treated simultaneously with AZ64 (p < 0.0001 for tumor size, p = 0.0006 for EFS). We conclude that AZ64 can inhibit growth of NTRK-expressing neuroblastomas both in vitro and in vivo. More importantly, it can significantly enhance the efficacy of conventional chemotherapy as well as local RT, presumably by inhibition of the NTRK2/BDNF autocrine survival pathway.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Neuroblastoma/tratamento farmacológico , Receptor trkB/antagonistas & inibidores , Animais , Camptotecina/administração & dosagem , Camptotecina/análogos & derivados , Linhagem Celular Tumoral , Terapia Combinada , Dacarbazina/administração & dosagem , Dacarbazina/análogos & derivados , Intervalo Livre de Doença , Humanos , Irinotecano , Camundongos , Camundongos Nus , Neuroblastoma/patologia , Neuroblastoma/radioterapia , Temozolomida , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Tumor-infiltrating myeloid cells convey proangiogenic programs that counteract the efficacy of antiangiogenic therapy. Here, we show that blocking angiopoietin-2 (ANG2), a TIE2 ligand and angiogenic factor expressed by activated endothelial cells (ECs), regresses the tumor vasculature and inhibits progression of late-stage, metastatic MMTV-PyMT mammary carcinomas and RIP1-Tag2 pancreatic insulinomas. ANG2 blockade did not inhibit recruitment of MRC1(+) TIE2-expressing macrophages (TEMs) but impeded their upregulation of Tie2, association with blood vessels, and ability to restore angiogenesis in tumors. Conditional Tie2 gene knockdown in TEMs was sufficient to decrease tumor angiogenesis. Our findings support a model wherein the ANG2-TIE2 axis mediates cell-to-cell interactions between TEMs and ECs that are important for tumor angiogenesis and can be targeted to induce effective antitumor responses.
Assuntos
Angiopoietina-2/fisiologia , Células Mieloides/fisiologia , Neoplasias Experimentais/irrigação sanguínea , Neoplasias Experimentais/prevenção & controle , Neovascularização Patológica/prevenção & controle , Receptores Proteína Tirosina Quinases/fisiologia , Adenoma de Células das Ilhotas Pancreáticas , Angiopoietina-2/antagonistas & inibidores , Animais , Comunicação Celular , Células Endoteliais/fisiologia , Regulação Neoplásica da Expressão Gênica , Humanos , Macrófagos/fisiologia , Neoplasias Mamárias Experimentais/irrigação sanguínea , Neoplasias Mamárias Experimentais/patologia , Neoplasias Mamárias Experimentais/prevenção & controle , Camundongos , Camundongos Endogâmicos C57BL , Metástase Neoplásica/prevenção & controle , Tumores Neuroendócrinos/prevenção & controle , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Receptor TIE-2RESUMO
PURPOSE: Chk1 inhibitors, such as AZD7762, are in clinical development in combination with cytotoxic agents for the treatment of solid tumors, including pancreatic cancers. To maximize the likelihood of their clinical success, it is essential to optimize drug scheduling as well as pharmacodynamic biomarkers in preclinical models. EXPERIMENTAL DESIGN: We tested multiple schedules of administration of gemcitabine and AZD7762 on the survival of pancreatic cancer cells. Potential pharmacodynamic biomarkers including pChk1, pChk2, pHistone H3, and caspase-3 were evaluated in vitro, followed by assessment of promising candidate biomarkers in vivo. We then went on to determine the contributions of PP2A and DNA damage to the mechanism(s) of induction of the identified biomarker, pS345 Chk1. RESULTS: AZD7762 given during and after or after gemcitabine administration produced maximum chemosensitization. In vivo, AZD7762 significantly inhibited the growth of pancreatic tumor xenografts in response to gemcitabine. Of the biomarkers assessed, pS345 Chk1 was most consistently increased in response to gemcitabine and AZD7762 in tumors and normal tissues (hair follicles). pS345 Chk1 induction in response to gemcitabine and AZD7762 occurred in the presence of PP2A inhibition and in association with elevated γH2AX, suggesting that DNA damage is an underlying mechanism. CONCLUSIONS: AZD7762 sensitizes pancreatic cancer cells and tumors to gemcitabine in association with induction of pS345 Chk1. Together these data support the clinical investigation of AZD7762 with gemcitabine in pancreatic cancer under a dosing schedule in which gemcitabine is administered concurrent with or before AZD7762 and in conjunction with skin biopsies to measure pS345 Chk1.
Assuntos
Desoxicitidina/análogos & derivados , Inibidores de Proteínas Quinases/farmacologia , Proteínas Quinases/metabolismo , Tiofenos/farmacologia , Ureia/análogos & derivados , Animais , Biomarcadores/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Quinase 1 do Ponto de Checagem , Dano ao DNA , Desoxicitidina/farmacologia , Histonas/metabolismo , Humanos , Camundongos , Neoplasias Pancreáticas/tratamento farmacológico , Fosforilação/efeitos dos fármacos , Transplante Heterólogo , Ureia/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto , GencitabinaRESUMO
BACKGROUND: TrkB expression is associated with poor prognosis for patients with neuroblastoma. AZ623 is a novel potent and selective inhibitor of the Trk family of tyrosine kinases. The authors hypothesized that AZ623 would inhibit TrkB-mediated signaling in neuroblastoma tumor cells and would be synergistic when combined with chemotherapy. METHODS: Neuroblastoma cell lines were screened for TrkB receptor mRNA expression and for their proliferation rates in response to brain-derived neurotrophic factor (BDNF). The effects of AZ623 on Trk receptor phosphorylation, signaling, and cell growth were evaluated in BDNF-treated neuroblastoma cells. Mice with human neuroblastoma xenograft tumors were treated with AZ623 alone and in combination with topotecan, and tumor growth rates were determined during and after treatment. RESULTS: Neuroblastoma cell lines expressed various levels of the TrkB receptor and demonstrated increased proliferation in response to BDNF. BDNF treatment stimulated TrkB phosphorylation and downstream signaling that could be inhibited by AZ623. Neuroblastoma cells demonstrated in vitro sensitivity to AZ623, with concentration that inhibits 50% (IC50) values between 0.8 to 7 µM. AZ623 treatment was found to inhibit BDNF-mediated neuroblastoma cell proliferation. Mice with human neuroblastoma xenograft tumors demonstrated tumor growth inhibition when treated with AZ623 and with AZ623 combined with topotecan. Limited tumor regrowth was noted in mice with tumors treated with AZ623 combined with topotecan after treatment discontinuation. CONCLUSIONS: AZ623 is a novel selective Trk inhibitor that inhibits BDNF-mediated signaling and neuroblastoma cell proliferation. AZ623 treatment inhibits the growth of human neuroblastoma xenograft tumors, and treatment with AZ623 combined with topotecan results in the prolonged inhibition of tumor regrowth. On the basis of these results, further preclinical development is warranted.
Assuntos
Neoplasias Encefálicas/tratamento farmacológico , Fator Neurotrófico Derivado do Encéfalo/antagonistas & inibidores , Proliferação de Células/efeitos dos fármacos , Neuroblastoma/tratamento farmacológico , Topotecan/administração & dosagem , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Neoplasias Encefálicas/patologia , Fator Neurotrófico Derivado do Encéfalo/farmacologia , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Camundongos Transgênicos , Neuroblastoma/patologia , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Receptor trkB/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Especificidade por Substrato , Topotecan/farmacologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Head and neck squamous cell carcinoma (HNSCC) is a biologically aggressive disease that has been modestly impacted by improvements in therapeutic strategies. Several lines of evidence support the role of TrkB for invasion and metastasis in various solid tumor models, and we have shown an important function of this receptor in HNSCC tumor biology. Therapeutic modulation of TrkB function has been supported in the literature by the development of small molecule inhibitors (SMI) with minimal success. To assess the validity of targeting TrkB in HNSCC, we tested a novel agent, AZ64 and show significant dose and time-dependent inhibition of cellular proliferation in cell lines. Genetic studies revealed the specificity of this compound for the TrkB receptor, as exposure of cells that had genetic suppression of TrkB did not demonstrate abrogated oncogenic signaling. We next assessed the impact of AZ64 as a chemotherapy-sensitizer and identified an enhancement of cisplatin-mediated anti-proliferation across all cell lines. We then demonstrated that AZ64 can overcome chemotherapy resistance in a novel model of cisplatin resistance in HNSCC. Modulation of the pro-oncogenic STAT3 and Src pathways was identified, suggesting molecular mechanisms of action for AZ64. In this study, we demonstrate the feasibility of targeting TrkB and suggest a novel approach for the treatment of some chemotherapy-resistant HNSCC.
Assuntos
Carcinoma de Células Escamosas/metabolismo , Proliferação de Células/efeitos dos fármacos , Cisplatino/farmacologia , Neoplasias de Cabeça e Pescoço/metabolismo , Receptor trkB/metabolismo , Animais , Antineoplásicos/farmacologia , Western Blotting , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Estudos de Viabilidade , Células HEK293 , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Imuno-Histoquímica , Concentração Inibidora 50 , Camundongos , Células NIH 3T3 , Interferência de RNA , Receptor trkB/genética , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Quinases da Família src/metabolismoRESUMO
Localized angiopoietin-2 (Ang2) expression has been shown to function as a key regulator of blood vessel remodeling and tumor angiogenesis, making it an attractive candidate for antiangiogenic therapy. A fully human monoclonal antibody (3.19.3) was developed, which may have significant pharmaceutical advantages over synthetic peptide-based approaches in terms of reduced immunogenicity and increased half-life to block Ang2 function. The 3.19.3 antibody potently binds Ang2 with an equilibrium dissociation constant of 86 pmol/L, leading to inhibition of Tie2 receptor phosphorylation in cell-based assays. In preclinical models, 3.19.3 treatment blocked blood vessel formation in Matrigel plug assays and in human tumor xenografts. In vivo studies with 3.19.3 consistently showed broad antitumor activity as a single agent across a panel of diverse subcutaneous and orthotopic xenograft models. Combination studies of 3.19.3 with cytotoxic drugs or anti-vascular endothelial growth factor agents showed significant improvements in antitumor activity over single-agent treatments alone with no apparent evidence of increased toxicity. Initial pharmacokinetic profiling studies in mice and nonhuman primates suggested that 3.19.3 has a predicted human half-life of 10 to 14 days. These studies provide preclinical data for 3.19.3 as a potential new antiangiogenic therapy as a single agent or in combination with chemotherapy or vascular endothelial growth factor inhibitors for the treatment of cancer.
Assuntos
Angiopoietina-2/imunologia , Anticorpos Monoclonais/farmacologia , Antineoplásicos/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Ensaios Antitumorais Modelo de Xenoenxerto , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/farmacocinética , Anticorpos Monoclonais/uso terapêutico , Especificidade de Anticorpos/efeitos dos fármacos , Antineoplásicos/administração & dosagem , Antineoplásicos/farmacocinética , Antineoplásicos/uso terapêutico , Morte Celular/efeitos dos fármacos , Colágeno/metabolismo , Combinação de Medicamentos , Humanos , Laminina/metabolismo , Camundongos , Neovascularização Patológica/tratamento farmacológico , Fosforilação/efeitos dos fármacos , Primatas , Ligação Proteica/efeitos dos fármacos , Proteoglicanas/metabolismo , Receptor TIE-2/metabolismoRESUMO
Tropomyosin-related kinases (TrkA, TrkB, and TrkC) are receptor tyrosine kinases that, along with their ligands, the neurotrophins, are involved in neuronal cell growth, development, and survival. The Trk-neurotrophin pathway may also play a role in tumorigenesis through oncogenic fusions, mutations, and autocrine signaling, prompting the development of novel Trk inhibitors as agents for cancer therapy. This report describes the identification of AZ-23, a novel, potent, and selective Trk kinase inhibitor. In vitro studies with AZ-23 showed improved selectivity over previous compounds and inhibition of Trk kinase activity in cells at low nanomolar concentrations. AZ-23 showed in vivo TrkA kinase inhibition and efficacy in mice following oral administration in a TrkA-driven allograft model and significant tumor growth inhibition in a Trk-expressing xenograft model of neuroblastoma. AZ-23 represents a potent and selective Trk kinase inhibitor from a novel series with the potential for use as a treatment for cancer.
Assuntos
Neuroblastoma/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Pirimidinas/antagonistas & inibidores , Pirimidinas/uso terapêutico , Receptor trkA/antagonistas & inibidores , Ensaios Antitumorais Modelo de Xenoenxerto , Administração Oral , Animais , Disponibilidade Biológica , Proliferação de Células/efeitos dos fármacos , Ensaio de Imunoadsorção Enzimática , Humanos , Immunoblotting , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos Nus , Camundongos SCID , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Fosforilação/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacocinética , Pirimidinas/farmacocinética , Receptores de Interleucina-2/fisiologia , Distribuição Tecidual , Células Tumorais CultivadasRESUMO
XR5944 (MLN944) is a novel bis-phenazine currently in phase I clinical trials that has demonstrated potent cytotoxic activity against a variety of tumor models. The combinations of XR5944 with carboplatin or doxorubicin were investigated in COR-L23/P human non-small-cell lung carcinoma (NSCLC) cells in vitro and the corresponding xenografts in vivo. In vitro cytotoxicity was evaluated by the sulforhodamine B assay and the drug interactions following simultaneous or sequential exposure were determined using median-effect analysis to calculate combination indices (CIs). XR5944 demonstrated potent cytotoxicity compared to either carboplatin or doxorubicin in COR-L23/P cells. Simultaneous or sequential exposure of XR5944 followed by carboplatin led to a synergistic response (CI<1), whereas the reverse order of addition showed an additive or antagonistic response (CI< or =1). Sequential administration of doxorubicin followed by XR5944 demonstrated marginally improved cytotoxicity (CI=1.31-0.77) than other schedules (CI=1.50-1.22) relative to individual drugs. Anti-tumor activity against COR-L23/P xenografts in nude mice was enhanced by administration of XR5944 (2 or 5 mg/kg) immediately before carboplatin (50 mg/kg) compared to single-agent treatment at the same doses. Improved efficacy was also observed by sequential administration of 7 mg/kg doxorubicin 48 h before 2.5 or 5 mg/kg XR5944. No additional toxicity was observed with combinations compared to single-agent treatment alone as determined by body weights. These data suggest that combinations of XR5944 with carboplatin or doxorubicin are of significant interest for clinical use, and that the schedule of administration may be important for achieving clinical efficacy over single-agent therapy.