CDC7 inhibition impairs neuroendocrine transformation in lung and prostate tumors through MYC degradation I
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ABSTRACT: Neuroendocrine (NE) transformation is a mechanism of resistance to targeted therapy in lung and prostate adenocarcinomas leading to poor prognosis. Upregulation of the cell cycle kinase CDC7 occurred in tumors undergoing NE transformation, after TP53/RB1 co-inactivation, leading to induced sensitivity to the CDC7 inhibitor simurosertib. CDC7 inhibition suppressed NE transdifferentiation and extended response to targeted therapy in in vivo models of NE transformation by inducing the proteasome-mediated degradation of MYC, implicated in stemness and histological transformation. Ectopic overexpression of a degradation-resistant MYC isoform reestablished the NE transformation phenotype observed on targeted therapy, even in the presence of simurosertib. CDC7 inhibition also markedly extended response to standard cytotoxics in lung and prostate small cell carcinoma models. These results nominate CDC7 inhibition as a strategy to constrain lineage plasticity and to effectively treat NE tumors. As simurosertib clinical efficacy trials are ongoing, this concept could be readily translated for patients at risk.
Project description:Neuroendocrine (NE) transformation is a mechanism of resistance to targeted therapy in lung and prostate adenocarcinomas leading to poor prognosis. Upregulation of the cell cycle kinase CDC7 occurred in tumors undergoing NE transformation, after TP53/RB1 co-inactivation, leading to induced sensitivity to the CDC7 inhibitor simurosertib. CDC7 inhibition suppressed NE transdifferentiation and extended response to targeted therapy in in vivo models of NE transformation by inducing the proteasome-mediated degradation of MYC, implicated in stemness and histological transformation. Ectopic overexpression of a degradation-resistant MYC isoform reestablished the NE transformation phenotype observed on targeted therapy, even in the presence of simurosertib. CDC7 inhibition also markedly extended response to standard cytotoxics in lung and prostate small cell carcinoma models. These results nominate CDC7 inhibition as a strategy to constrain lineage plasticity and to effectively treat NE tumors. As simurosertib clinical efficacy trials are ongoing, this concept could be readily translated for patients at risk.
Project description:Neuroendocrine (NE) transformation is a mechanism of resistance to targeted therapy in lung and prostate adenocarcinomas leading to poor prognosis. Upregulation of the cell cycle kinase CDC7 occurred in tumors undergoing NE transformation, after TP53/RB1 co-inactivation, leading to induced sensitivity to the CDC7 inhibitor simurosertib. CDC7 inhibition suppressed NE transdifferentiation and extended response to targeted therapy in in vivo models of NE transformation by inducing the proteasome-mediated degradation of MYC, implicated in stemness and histological transformation. Ectopic overexpression of a degradation-resistant MYC isoform reestablished the NE transformation phenotype observed on targeted therapy, even in the presence of simurosertib. CDC7 inhibition also markedly extended response to standard cytotoxics in lung and prostate small cell carcinoma models. These results nominate CDC7 inhibition as a strategy to constrain lineage plasticity and to effectively treat NE tumors. As simurosertib clinical efficacy trials are ongoing, this concept could be readily translated for patients at risk.
Project description:Neuroendocrine (NE) transformation is a mechanism of resistance to targeted therapy in lung and prostate adenocarcinomas leading to poor prognosis. Upregulation of the cell cycle kinase CDC7 occurred in tumors undergoing NE transformation, after TP53/RB1 co-inactivation, leading to induced sensitivity to the CDC7 inhibitor simurosertib. CDC7 inhibition suppressed NE transdifferentiation and extended response to targeted therapy in in vivo models of NE transformation by inducing the proteasome-mediated degradation of MYC, implicated in stemness and histological transformation. Ectopic overexpression of a degradation-resistant MYC isoform reestablished the NE transformation phenotype observed on targeted therapy, even in the presence of simurosertib. CDC7 inhibition also markedly extended response to standard cytotoxics in lung and prostate small cell carcinoma models. These results nominate CDC7 inhibition as a strategy to constrain lineage plasticity and to effectively treat NE tumors. As simurosertib clinical efficacy trials are ongoing, this concept could be readily translated for patients at risk.
Project description:In lung and prostate adenocarcinomas, neuroendocrine (NE) transformation to an aggressive derivative resembling small cell lung cancer (SCLC) is associated with poor prognosis. We previously described dependency of SCLC on the nuclear transporter exportin 1. Here we explored the role of exportin 1 in NE transformation. We observed upregulated exportin 1 in lung and prostate pre-transformation adenocarcinomas. Exportin 1 was induced upregulated following genetic inactivation of TP53 and RB1 in lung and prostate adenocarcinoma cell lines, accompanied by increased sensitivity to the exportin 1 inhibitor selinexor in vitro. Exportin 1 inhibition prevented NE transformation and extended response to targeted therapies in both lung anddifferent TP53/RB1-inactivated prostate adenocarcinoma xenograft models that acquire NE features upon treatment with the AR inhibitor enzalutamide, and extended response to the EGFR inhibitor osimertinib in a lung cancer transformation patient-derived xenograft (PDX) model exhibiting combined adenocarcinoma/SCLC histology. Ectopic SOX2 expression restored the enzalutamide-promoted NE transformationNE phenotype on adenocarcinoma-to-NE transformation xenograft models despite selinexor treatment. Selinexor sensitized NE-transformed lung and prostate small cell carcinoma PDXs tumors after NE transformation to standard cytotoxics. Together these data nominate exportin 1 inhibition as a novel potential therapeutic approach target to constrain lineage plasticity and prevent or treat NE transformation in lung and prostate adenocarcinoma.
Project description:In lung and prostate adenocarcinomas, neuroendocrine (NE) transformation to an aggressive derivative resembling small cell lung cancer (SCLC) is associated with poor prognosis. We previously described dependency of SCLC on the nuclear transporter exportin 1. Here we explored the role of exportin 1 in NE transformation. We observed upregulated exportin 1 in lung and prostate pre-transformation adenocarcinomas. Exportin 1 was induced upregulated following genetic inactivation of TP53 and RB1 in lung and prostate adenocarcinoma cell lines, accompanied by increased sensitivity to the exportin 1 inhibitor selinexor in vitro. Exportin 1 inhibition prevented NE transformation and extended response to targeted therapies in both lung anddifferent TP53/RB1-inactivated prostate adenocarcinoma xenograft models that acquire NE features upon treatment with the AR inhibitor enzalutamide, and extended response to the EGFR inhibitor osimertinib in a lung cancer transformation patient-derived xenograft (PDX) model exhibiting combined adenocarcinoma/SCLC histology. Ectopic SOX2 expression restored the enzalutamide-promoted NE transformationNE phenotype on adenocarcinoma-to-NE transformation xenograft models despite selinexor treatment. Selinexor sensitized NE-transformed lung and prostate small cell carcinoma PDXs tumors after NE transformation to standard cytotoxics. Together these data nominate exportin 1 inhibition as a novel potential therapeutic approach target to constrain lineage plasticity and prevent or treat NE transformation in lung and prostate adenocarcinoma.