RESUMO
PURPOSE: Proficient DNA repair by homologous recombination (HR) facilitates resistance to chemoradiation in glioma stem cells (GSC). We evaluated whether compromising HR by targeting HSP90, a molecular chaperone required for the function of key HR proteins, using onalespib, a long-acting, brain-penetrant HSP90 inhibitor, would sensitize high-grade gliomas to chemoradiation in vitro and in vivo. EXPERIMENTAL DESIGN: The ability of onalespib to deplete HR client proteins, impair HR repair capacity, and sensitize glioblastoma (GBM) to chemoradiation was evaluated in vitro in GSCs, and in vivo using zebrafish and mouse intracranial glioma xenograft models. The effects of HSP90 inhibition on the transcriptome and cytoplasmic proteins was assessed in GSCs and in ex vivo organotypic human glioma slice cultures. RESULTS: Treatment with onalespib depleted CHK1 and RAD51, two key proteins of the HR pathway, and attenuated HR repair, sensitizing GSCs to the combination of radiation and temozolomide (TMZ). HSP90 inhibition reprogrammed the transcriptome of GSCs and broadly altered expression of cytoplasmic proteins including known and novel client proteins relevant to GSCs. The combination of onalespib with radiation and TMZ extended survival in a zebrafish and a mouse xenograft model of GBM compared with the standard of care (radiation and TMZ) or onalespib with radiation. CONCLUSIONS: The results of this study demonstrate that targeting HR by HSP90 inhibition sensitizes GSCs to radiation and chemotherapy and extends survival in zebrafish and mouse intracranial models of GBM. These results provide a preclinical rationale for assessment of HSP90 inhibitors in combination with chemoradiation in patients with GBM.
Assuntos
Antineoplásicos , Neoplasias Encefálicas , Glioblastoma , Glioma , Animais , Antineoplásicos/farmacologia , Benzamidas , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/genética , Linhagem Celular Tumoral , Reparo do DNA , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Glioblastoma/radioterapia , Glioma/tratamento farmacológico , Glioma/genética , Glioma/radioterapia , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Proteínas de Choque Térmico/metabolismo , Humanos , Isoindóis , Camundongos , Temozolomida/farmacologia , Temozolomida/uso terapêutico , Ensaios Antitumorais Modelo de Xenoenxerto , Peixe-ZebraRESUMO
BACKGROUND: Glioblastoma (GBM) remains one of the least successfully treated cancers. It is essential to understand the basic biology of this lethal disease and investigate novel pharmacological targets to treat GBM. The aims of this study were to determine the biological consequences of elevated expression of ΔNp73, an N-terminal truncated isoform of TP73, and to evaluate targeting of its downstream mediators, the angiopoietin 1 (ANGPT1)/tunica interna endothelial cell kinase 2 (Tie2) axis, by using a highly potent, orally available small-molecule inhibitor (rebastinib) in GBM. METHODS: ΔNp73 expression was assessed in glioma sphere cultures, xenograft glioblastoma tumors, and glioblastoma patients by western blot, quantitative reverse transcription PCR, and immunohistochemistry. Immunoprecipitation, chromatin immunoprecipitation (ChiP) and sequential ChIP were performed to determine the interaction between ΔNp73 and E26 transformation-specific (ETS) proto-oncogene 2 (ETS2) proteins. The oncogenic consequences of ΔNp73 expression in glioblastomas were examined by in vitro and in vivo experiments, including orthotopic zebrafish and mouse intracranial-injection models. Effects of rebastinib on growth of established tumors and survival were examined in an intracranial-injection mouse model. RESULTS: ΔNp73 upregulates both ANGPT1 and Tie2 transcriptionally through ETS conserved binding sites on the promoters by interacting with ETS2. Elevated expression of ΔNp73 promotes tumor progression by mediating angiogenesis and survival. Therapeutic targeting of downstream ΔNp73 signaling pathways by rebastinib inhibits growth of established tumors and extends survival in preclinical models of glioblastoma. CONCLUSION: Aberrant expression of ΔNp73 in GBM promotes tumor progression through autocrine and paracrine signaling dependent on Tie2 activation by ANGPT1. Disruption of this signaling by rebastinib improves tumor response to treatment in glioblastoma.
Assuntos
Antineoplásicos/administração & dosagem , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Glioblastoma/metabolismo , Glioblastoma/patologia , Proteína Proto-Oncogênica c-ets-2/metabolismo , Pirazóis/administração & dosagem , Piridinas/administração & dosagem , Quinolinas/administração & dosagem , Proteína Tumoral p73/metabolismo , Animais , Neoplasias Encefálicas/tratamento farmacológico , Linhagem Celular Tumoral/efeitos dos fármacos , Modelos Animais de Doenças , Glioblastoma/tratamento farmacológico , Humanos , Camundongos Transgênicos , Neovascularização Patológica/metabolismo , Proto-Oncogene Mas , Análise de Sobrevida , Peixe-ZebraRESUMO
Xenograft cell transplantation into immunodeficient mice has become the gold standard for assessing pre-clinical efficacy of cancer drugs, yet direct visualization of single-cell phenotypes is difficult. Here, we report an optically-clear prkdc-/-, il2rga-/- zebrafish that lacks adaptive and natural killer immune cells, can engraft a wide array of human cancers at 37°C, and permits the dynamic visualization of single engrafted cells. For example, photoconversion cell-lineage tracing identified migratory and proliferative cell states in human rhabdomyosarcoma, a pediatric cancer of muscle. Additional experiments identified the preclinical efficacy of combination olaparib PARP inhibitor and temozolomide DNA-damaging agent as an effective therapy for rhabdomyosarcoma and visualized therapeutic responses using a four-color FUCCI cell-cycle fluorescent reporter. These experiments identified that combination treatment arrested rhabdomyosarcoma cells in the G2 cell cycle prior to induction of apoptosis. Finally, patient-derived xenografts could be engrafted into our model, opening new avenues for developing personalized therapeutic approaches in the future.
Assuntos
Animais Geneticamente Modificados/metabolismo , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Neoplasias Musculares , Rabdomiossarcoma , Peixe-Zebra/metabolismo , Animais , Animais Geneticamente Modificados/genética , Animais Geneticamente Modificados/imunologia , Feminino , Xenoenxertos , Humanos , Células K562 , Masculino , Neoplasias Musculares/tratamento farmacológico , Neoplasias Musculares/imunologia , Neoplasias Musculares/metabolismo , Neoplasias Musculares/patologia , Transplante de Neoplasias , Ftalazinas/farmacologia , Piperazinas/farmacologia , Rabdomiossarcoma/tratamento farmacológico , Rabdomiossarcoma/imunologia , Rabdomiossarcoma/metabolismo , Rabdomiossarcoma/patologia , Temozolomida/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto , Peixe-Zebra/genética , Peixe-Zebra/imunologiaRESUMO
Background: In spite of standard multimodal therapy consisting of surgical resection followed by radiation and concurrent chemotherapy, prognosis for glioblastoma (GBM) patients remains poor. The identification of both differentiated and undifferentiated "stem cell like" populations in the tumor highlights the significance of finding novel targets that affect the heterogeneous tumor cell population. Protein arginine methyltransferase 5 (PRMT5) is one such candidate gene whose nuclear expression correlates with poor survival and has been reported to be required for survival of differentiated GBM cells and self-renewal of undifferentiated GBM cells. In the current study we screened the specificity and efficacy of 4 novel PRMT5 inhibitors in the treatment of GBM. Methods: Efficacies of these inhibitors were screened using an in vitro GBM neurosphere model and an in vivo intracranial zebrafish model of glioma. Standard molecular biology methods were employed to investigate changes in cell cycle, growth, and senescence. Results: In vitro and in vivo studies revealed that among the 4 PRMT5 inhibitors, treatment of GBM cells with compound 5 (CMP5) mirrored the effects of PRMT5 knockdown wherein it led to apoptosis of differentiated GBM cells and drove undifferentiated primary patient derived GBM cells into a nonreplicative senescent state. Conclusion: In vivo antitumor efficacy combined with the specificity of CMP5 underscores the importance of developing it for translation.
Assuntos
Neoplasias Encefálicas/patologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glioblastoma/patologia , Inibidores de Proteínas Quinases/farmacologia , Proteína-Arginina N-Metiltransferases/antagonistas & inibidores , Bibliotecas de Moléculas Pequenas/farmacologia , Peixe-Zebra/metabolismo , Animais , Apoptose , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/metabolismo , Ciclo Celular , Diferenciação Celular , Proliferação de Células , Regulação Enzimológica da Expressão Gênica , Glioblastoma/tratamento farmacológico , Glioblastoma/metabolismo , Humanos , Camundongos , Proteína-Arginina N-Metiltransferases/genética , Proteína-Arginina N-Metiltransferases/metabolismo , Transdução de Sinais , Esferoides Celulares , Ensaios Antitumorais Modelo de Xenoenxerto , Peixe-Zebra/genética , Peixe-Zebra/crescimento & desenvolvimentoRESUMO
Purpose: HSP90, a highly conserved molecular chaperone that regulates the function of several oncogenic client proteins, is altered in glioblastoma. However, HSP90 inhibitors currently in clinical trials are short-acting, have unacceptable toxicities, or are unable to cross the blood-brain barrier (BBB). We examined the efficacy of onalespib, a potent, long-acting novel HSP90 inhibitor as a single agent and in combination with temozolomide (TMZ) against gliomas in vitro and in vivoExperimental Design: The effect of onalespib on HSP90, its client proteins, and on the biology of glioma cell lines and patient-derived glioma-initiating cells (GSC) was determined. Brain and plasma pharmacokinetics of onalespib and its ability to inhibit HSP90 in vivo were assessed in non-tumor-bearing mice. Its efficacy as a single agent or in combination with TMZ was assessed in vitro and in vivo using zebrafish and patient-derived GSC xenograft mouse glioma models.Results: Onalespib-mediated HSP90 inhibition depleted several survival-promoting client proteins such as EGFR, EGFRvIII, and AKT, disrupted their downstream signaling, and decreased the proliferation, migration, angiogenesis, and survival of glioma cell lines and GSCs. Onalespib effectively crossed the BBB to inhibit HSP90 in vivo and extended survival as a single agent in zebrafish xenografts and in combination with TMZ in both zebrafish and GSC mouse xenografts.Conclusions: Our results demonstrate the long-acting effects of onalespib against gliomas in vitro and in vivo, which combined with its ability to cross the BBB support its development as a potential therapeutic agent in combination with TMZ against gliomas. Clin Cancer Res; 23(20); 6215-26. ©2017 AACR.
Assuntos
Antineoplásicos/farmacologia , Benzamidas/farmacologia , Dacarbazina/análogos & derivados , Glioma/metabolismo , Glioma/patologia , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Isoindóis/farmacologia , Animais , Antineoplásicos/farmacocinética , Benzamidas/farmacocinética , Barreira Hematoencefálica/metabolismo , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Dacarbazina/farmacocinética , Dacarbazina/farmacologia , Modelos Animais de Doenças , Sinergismo Farmacológico , Quimioterapia Combinada , Receptores ErbB/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Feminino , Expressão Gênica , Glioma/tratamento farmacológico , Glioma/mortalidade , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Isoindóis/farmacocinética , Camundongos , Células-Tronco Neoplásicas/metabolismo , Transporte Proteico , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Quinases S6 Ribossômicas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Taxa de Sobrevida , Temozolomida , Ensaios Antitumorais Modelo de Xenoenxerto , Peixe-ZebraRESUMO
Glioblastoma (GBM) is a highly aggressive brain cancer with limited treatments and poor patient survival. GBM tumors are heterogeneous containing a complex mixture of dividing cells, differentiated cells, and cancer stem cells. It is unclear, however, how these different cell populations contribute to tumor growth or whether they exhibit differential responses to chemotherapy. Here we set out to address these questions using a zebrafish xenograft transplant model (Welker et al., 2016). We found that a small population of differentiated vimentin-positive tumor cells, but a majority of Sox2-positive putative cancer stem cells, were dividing during tumor growth. We also observed co-expression of Sox2 and GFAP, another suggested marker of glioma cancer stem cells, indicating that the putative cancer stem cells in GBM9 tumors expressed both of these markers. To determine how these different tumor cell populations responded to chemotherapy, we treated animals with temozolomide (TMZ) and assessed these cell populations immediately after treatment and 5 and 10days after treatment cessation. As expected we found a significant decrease in dividing cells after treatment. We also found a significant decrease in vimentin-positive cells, but not in Sox2 or GFAP-positive cells. However, the Sox2-positive cells significantly increased 5days after TMZ treatment. These data support that putative glioma cancer stem cells are more resistant to TMZ treatment and may contribute to tumor regrowth after chemotherapy.
Assuntos
Neoplasias Encefálicas/patologia , Glioblastoma/patologia , Animais , Neoplasias Encefálicas/tratamento farmacológico , Linhagem Celular Tumoral , Dacarbazina/análogos & derivados , Dacarbazina/farmacologia , Modelos Animais de Doenças , Glioblastoma/tratamento farmacológico , Xenoenxertos/efeitos dos fármacos , Xenoenxertos/transplante , Humanos , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/patologia , Temozolomida , Ensaios Antitumorais Modelo de Xenoenxerto/métodosRESUMO
Glioblastoma (GBM) is a deadly brain cancer, for which few effective drug treatments are available. Several studies have used zebrafish models to study GBM, but a standardized approach to modeling GBM in zebrafish was lacking to date, preventing comparison of data across studies. Here, we describe a new, standardized orthotopic xenotransplant model of GBM in zebrafish. Dose-response survival assays were used to define the optimal number of cells for tumor formation. Techniques to measure tumor burden and cell spread within the brain over real time were optimized using mouse neural stem cells as control transplants. Applying this standardized approach, we transplanted two patient-derived GBM cell lines, serum-grown adherent cells and neurospheres, into the midbrain region of embryonic zebrafish and analyzed transplanted larvae over time. Progressive brain tumor growth and premature larval death were observed using both cell lines; however, fewer transplanted neurosphere cells were needed for tumor growth and lethality. Tumors were heterogeneous, containing both cells expressing stem cell markers and cells expressing markers of differentiation. A small proportion of transplanted neurosphere cells expressed glial fibrillary acidic protein (GFAP) or vimentin, markers of more differentiated cells, but this number increased significantly during tumor growth, indicating that these cells undergo differentiation in vivo. By contrast, most serum-grown adherent cells expressed GFAP and vimentin at the earliest times examined post-transplant. Both cell types produced brain tumors that contained Sox2(+) cells, indicative of tumor stem cells. Transplanted larvae were treated with currently used GBM therapeutics, temozolomide or bortezomib, and this resulted in a reduction in tumor volume in vivo and an increase in survival. The standardized model reported here facilitates robust and reproducible analysis of glioblastoma tumor cells in real time and provides a platform for drug screening.