RESUMEN
Somatic mutations in the isocitrate dehydrogenase 2 gene (IDH2) contribute to the pathogenesis of acute myeloid leukaemia (AML) through the production of the oncometabolite 2-hydroxyglutarate (2HG)1-8. Enasidenib (AG-221) is an allosteric inhibitor that binds to the IDH2 dimer interface and blocks the production of 2HG by IDH2 mutants9,10. In a phase I/II clinical trial, enasidenib inhibited the production of 2HG and induced clinical responses in relapsed or refractory IDH2-mutant AML11. Here we describe two patients with IDH2-mutant AML who had a clinical response to enasidenib followed by clinical resistance, disease progression, and a recurrent increase in circulating levels of 2HG. We show that therapeutic resistance is associated with the emergence of second-site IDH2 mutations in trans, such that the resistance mutations occurred in the IDH2 allele without the neomorphic R140Q mutation. The in trans mutations occurred at glutamine 316 (Q316E) and isoleucine 319 (I319M), which are at the interface where enasidenib binds to the IDH2 dimer. The expression of either of these mutant disease alleles alone did not induce the production of 2HG; however, the expression of the Q316E or I319M mutation together with the R140Q mutation in trans allowed 2HG production that was resistant to inhibition by enasidenib. Biochemical studies predicted that resistance to allosteric IDH inhibitors could also occur via IDH dimer-interface mutations in cis, which was confirmed in a patient with acquired resistance to the IDH1 inhibitor ivosidenib (AG-120). Our observations uncover a mechanism of acquired resistance to a targeted therapy and underscore the importance of 2HG production in the pathogenesis of IDH-mutant malignancies.
Asunto(s)
Aminopiridinas/farmacología , Resistencia a Antineoplásicos/genética , Isocitrato Deshidrogenasa/antagonistas & inhibidores , Isocitrato Deshidrogenasa/genética , Leucemia Mieloide Aguda/genética , Proteínas Mutantes/genética , Mutación , Multimerización de Proteína/genética , Triazinas/farmacología , Alelos , Sitio Alostérico/efectos de los fármacos , Sitio Alostérico/genética , Aminopiridinas/química , Aminopiridinas/uso terapéutico , Animales , Ensayos Clínicos Fase I como Asunto , Ensayos Clínicos Fase II como Asunto , Progresión de la Enfermedad , Resistencia a Antineoplásicos/efectos de los fármacos , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/uso terapéutico , Femenino , Glutamina/genética , Glutaratos/sangre , Glutaratos/metabolismo , Células HEK293 , Humanos , Isoleucina/genética , Leucemia Mieloide Aguda/sangre , Leucemia Mieloide Aguda/tratamiento farmacológico , Ratones , Ratones Endogámicos C57BL , Modelos Moleculares , Proteínas Mutantes/antagonistas & inhibidores , Triazinas/química , Triazinas/uso terapéuticoRESUMEN
INTRODUCTION: Small Cell Lung Cancer (SCLC) can be classified into transcriptional subtypes with distinct degrees of neuroendocrine (NE) differentiation. Recent evidence supports plasticity among subtypes with a bias toward adoption of low-NE states during disease progression or upon acquired chemotherapy resistance. Here, we identify a role for SMARCA4, the catalytic subunit of the SWI/SNF complex, as a regulator of subtype shift in SCLC. METHODS: ATACseq and RNAseq experiments were performed in SCLC cells after pharmacological inhibition of SMARCA4. DNA binding of SMARCA4 was characterized by ChIPseq in high-NE SCLC patient derived xenografts (PDXs). Enrichment analyses were applied to transcriptomic data. Combination of FHD-286 and afatinib was tested in vitro and in a set of chemo-resistant SCLC PDXs in vivo. RESULTS: SMARCA4 expression positively correlates with that of NE genes in both SCLC cell lines and patient tumors. Pharmacological inhibition of SMARCA4 with FHD-286 induces the loss of NE features and downregulates neuroendocrine and neuronal signaling pathways while activating non-NE factors. SMARCA4 binds to gene loci encoding NE-lineage transcription factors ASCL1 and NEUROD1 and alters chromatin accessibility, enhancing NE programs. Enrichment analysis applied to high-confidence SMARCA4 targets confirmed neuron related pathways as the top GO Biological processes regulated by SMARCA4 in SCLC. In parallel, SMARCA4 also controls REST, a known suppressor of the NE phenotype, by regulating SRRM4-dependent REST transcript splicing. Furthermore, SMARCA4 inhibition drives ERBB pathway activation in SCLC, rendering SCLC tumors sensitive to afatinib. CONCLUSIONS: This study nominates SMARCA4 as a key regulator of the NE state plasticity and defines a novel therapeutic strategy for SCLC.
Asunto(s)
ADN Helicasas , Neoplasias Pulmonares , Proteínas Nucleares , Carcinoma Pulmonar de Células Pequeñas , Factores de Transcripción , Humanos , Carcinoma Pulmonar de Células Pequeñas/genética , Carcinoma Pulmonar de Células Pequeñas/metabolismo , Carcinoma Pulmonar de Células Pequeñas/patología , Carcinoma Pulmonar de Células Pequeñas/tratamiento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/tratamiento farmacológico , ADN Helicasas/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Línea Celular Tumoral , Animales , Ratones , Regulación Neoplásica de la Expresión Génica , Proteínas RepresorasRESUMEN
Neuroendocrine (NE) transformation is a mechanism of resistance to targeted therapy in lung and prostate adenocarcinomas leading to poor prognosis. Up to date, even if patients at high risk of transformation can be identified by the occurrence of Tumor Protein P53 (TP53) and Retinoblastoma Transcriptional Corepressor 1 (RB1) mutations in their tumors, no therapeutic strategies are available to prevent or delay histological transformation. Upregulation of the cell cycle kinase Cell Division Cycle 7 (CDC7) occurred in tumors during the initial steps of NE transformation, already 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 the MYC Proto-Oncogen (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 (cisplatin, irinotecan) in lung and prostate small cell carcinoma models. These results nominate CDC7 inhibition as a therapeutic strategy to constrain lineage plasticity, as well as to effectively treat NE tumors de novo or after transformation. As simurosertib clinical efficacy trials are ongoing, this concept could be readily translated for patients at risk of transformation.
Asunto(s)
Proteínas de Ciclo Celular , Neoplasias Pulmonares , Neoplasias de la Próstata , Proteínas Proto-Oncogénicas c-myc , Humanos , Masculino , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/tratamiento farmacológico , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Línea Celular Tumoral , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Ratones , Animales , Tumores Neuroendocrinos/genética , Tumores Neuroendocrinos/patología , Tumores Neuroendocrinos/metabolismo , Tumores Neuroendocrinos/tratamiento farmacológico , Proteolisis/efectos de los fármacos , Proteínas de Unión a Retinoblastoma/genética , Proteínas de Unión a Retinoblastoma/metabolismo , Ubiquitina-Proteína LigasasRESUMEN
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 up-regulated exportin 1 in lung and prostate pretransformation adenocarcinomas. Exportin 1 was up-regulated after 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 in different TP53/RB1-inactivated prostate adenocarcinoma xenograft models that acquire NE features upon treatment with the aromatase 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 phenotype on adenocarcinoma-to-NE transformation xenograft models despite selinexor treatment. Selinexor sensitized NE-transformed lung and prostate small cell carcinoma PDXs to standard cytotoxics. Together, these data nominate exportin 1 inhibition as a potential therapeutic target to constrain lineage plasticity and prevent or treat NE transformation in lung and prostate adenocarcinoma.
Asunto(s)
Adenocarcinoma , Neoplasias Pulmonares , Neoplasias de la Próstata , Factores de Transcripción SOXB1 , Carcinoma Pulmonar de Células Pequeñas , Humanos , Masculino , Adenocarcinoma/patología , Regulación hacia Abajo , Neoplasias Pulmonares/patología , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias de la Próstata/patología , Carcinoma Pulmonar de Células Pequeñas/genética , Factores de Transcripción SOXB1/genética , Factores de Transcripción SOXB1/metabolismo , Animales , Proteína Exportina 1RESUMEN
Activation of mitogenic signaling pathways is a common oncogenic driver of many solid tumors including lung cancer. Although activating mutations in the mitogen-activated protein kinase (MAPK) pathway are prevalent in non-small cell lung cancers, MAPK pathway activity, counterintuitively, is relatively suppressed in the more aggressively proliferative small cell lung cancer (SCLC). Here, we elucidate the role of the MAPK pathway and how it interacts with other signaling pathways in SCLC. We find that the most common SCLC subtype, SCLC-A associated with high expression of ASCL1, is selectively sensitive to MAPK activation in vitro and in vivo through induction of cell-cycle arrest and senescence. We show strong upregulation of ERK negative feedback regulators and STAT signaling upon MAPK activation in SCLC-A lines. These findings provide insight into the complexity of signaling networks in SCLC and suggest subtype-specific mitogenic vulnerabilities.
RESUMEN
The cell of origin of oncogenic transformation is a determinant of therapeutic sensitivity, but the mechanisms governing cell-of-origin-driven differences in therapeutic response have not been delineated. Leukemias initiating in hematopoietic stem cells (HSC) are less sensitive to chemotherapy and highly express the transcription factor MECOM (EVI1) compared with leukemias derived from myeloid progenitors. Here, we compared leukemias initiated in either HSCs or myeloid progenitors to reveal a novel function for EVI1 in modulating p53 protein abundance and activity. HSC-derived leukemias exhibit decreased apoptotic priming, attenuated p53 transcriptional output, and resistance to lysine-specific demethylase 1 (LSD1) inhibitors in addition to classical genotoxic stresses. p53 loss of function in Evi1 lo progenitor-derived leukemias induces resistance to LSD1 inhibition, and EVI1hi leukemias are sensitized to LSD1 inhibition by venetoclax. Our findings demonstrate a role for EVI1 in p53 wild-type cancers in reducing p53 function and provide a strategy to circumvent drug resistance in chemoresistant EVI1 hi acute myeloid leukemia. SIGNIFICANCE: We demonstrate that the cell of origin of leukemia initiation influences p53 activity and dictates therapeutic sensitivity to pharmacologic LSD1 inhibitors via the transcription factor EVI1. We show that drug resistance could be overcome in HSC-derived leukemias by combining LSD1 inhibition with venetoclax.See related commentary by Gu et al., p. 1445.This article is highlighted in the In This Issue feature, p. 1426.