RESUMO
Large-scale human genetic data1-3 have shown that cancer mutations display strong tissue-selectivity, but how this selectivity arises remains unclear. Here, using experimental models, functional genomics and analyses of patient samples, we demonstrate that the lineage transcription factor paired box 8 (PAX8) is required for oncogenic signalling by two common genetic alterations that cause clear cell renal cell carcinoma (ccRCC) in humans: the germline variant rs7948643 at 11q13.3 and somatic inactivation of the von Hippel-Lindau tumour suppressor (VHL)4-6. VHL loss, which is observed in about 90% of ccRCCs, can lead to hypoxia-inducible factor 2α (HIF2A) stabilization6,7. We show that HIF2A is preferentially recruited to PAX8-bound transcriptional enhancers, including a pro-tumorigenic cyclin D1 (CCND1) enhancer that is controlled by PAX8 and HIF2A. The ccRCC-protective allele C at rs7948643 inhibits PAX8 binding at this enhancer and downstream activation of CCND1 expression. Co-option of a PAX8-dependent physiological programme that supports the proliferation of normal renal epithelial cells is also required for MYC expression from the ccRCC metastasis-associated amplicons at 8q21.3-q24.3 (ref. 8). These results demonstrate that transcriptional lineage factors are essential for oncogenic signalling and that they mediate tissue-specific cancer risk associated with somatic and inherited genetic variants.
Assuntos
Carcinogênese , Neoplasias Renais , Fator de Transcrição PAX8 , Transdução de Sinais , Alelos , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Carcinogênese/genética , Carcinoma de Células Renais/metabolismo , Carcinoma de Células Renais/patologia , Ciclina D1/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Rim/metabolismo , Rim/patologia , Neoplasias Renais/metabolismo , Neoplasias Renais/patologia , Mutação , Fator de Transcrição PAX8/genética , Fator de Transcrição PAX8/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Proteína Supressora de Tumor Von Hippel-Lindau/genéticaRESUMO
Transcriptional networks are critical for the establishment of tissue-specific cellular states in health and disease, including cancer. Yet, the transcriptional circuits that control carcinogenesis remain poorly understood. Here we report that Kruppel like factor 6 (KLF6), a transcription factor of the zinc finger family, regulates lipid homeostasis in clear cell renal cell carcinoma (ccRCC). We show that KLF6 supports the expression of lipid metabolism genes and promotes the expression of PDGFB, which activates mTOR signalling and the downstream lipid metabolism regulators SREBF1 and SREBF2. KLF6 expression is driven by a robust super enhancer that integrates signals from multiple pathways, including the ccRCC-initiating VHL-HIF2A pathway. These results suggest an underlying mechanism for high mTOR activity in ccRCC cells. More generally, the link between super enhancer-driven transcriptional networks and essential metabolic pathways may provide clues to the mechanisms that maintain the stability of cell identity-defining transcriptional programmes in cancer.
Assuntos
Carcinogênese/genética , Carcinoma de Células Renais/genética , Neoplasias Renais/genética , Fator 6 Semelhante a Kruppel/metabolismo , Metabolismo dos Lipídeos/genética , Animais , Carcinoma de Células Renais/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Elementos Facilitadores Genéticos/genética , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Células HEK293 , Humanos , Rim/patologia , Neoplasias Renais/patologia , Fator 6 Semelhante a Kruppel/genética , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos Nus , Camundongos SCID , Proteínas Proto-Oncogênicas c-sis/genética , Transdução de Sinais/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Metastases, the spread of cancer cells to distant organs, cause the majority of cancer-related deaths. Few metastasis-specific driver mutations have been identified, suggesting aberrant gene regulation as a source of metastatic traits. However, how metastatic gene expression programs arise is poorly understood. Here, using human-derived metastasis models of renal cancer, we identify transcriptional enhancers that promote metastatic carcinoma progression. Specific enhancers and enhancer clusters are activated in metastatic cancer cell populations, and the associated gene expression patterns are predictive of poor patient outcome in clinical samples. We find that the renal cancer metastasis-associated enhancer complement consists of multiple coactivated tissue-specific enhancer modules. Specifically, we identify and functionally characterize a coregulatory enhancer cluster, activated by the renal cancer driver HIF2A and an NF-κB-driven lymphoid element, as a mediator of metastasis in vivo We conclude that oncogenic pathways can acquire metastatic phenotypes through cross-lineage co-option of physiologic epigenetic enhancer states.Significance: Renal cancer is associated with significant mortality due to metastasis. We show that in metastatic renal cancer, functionally important metastasis genes are activated via co-option of gene regulatory enhancer modules from distant developmental lineages, thus providing clues to the origins of metastatic cancer. Cancer Discov; 8(7); 850-65. ©2018 AACR.This article is highlighted in the In This Issue feature, p. 781.