RESUMO
Previous work identified RMEL3 as a lncRNA with enriched expression in melanoma. Analysis of The Cancer Genome Atlas (TCGA) data confirmed RMEL3 enriched expression in melanoma and demonstrated its association with the presence of BRAFV600E. RMEL3 siRNA-mediated silencing markedly reduced (95%) colony formation in different BRAFV600E melanoma cell lines. Multiple genes of the MAPK and PI3K pathways found to be correlated with RMEL3 in TCGA samples were experimentally confirmed. RMEL3 knockdown led to downregulation of activators or effectors of these pathways, including FGF2, FGF3, DUSP6, ITGB3 and GNG2. RMEL3 knockdown induces gain of protein levels of tumor suppressor PTEN and the G1/S cyclin-Cdk inhibitors p21 and p27, as well as a decrease of pAKT (T308), BRAF, pRB (S807, S811) and cyclin B1. Consistently, knockdown resulted in an accumulation of cells in G1 phase and subG0/G1 in an asynchronously growing population. Thus, TCGA data and functional experiments demonstrate that RMEL3 is required for MAPK and PI3K signaling, and its knockdown decrease BRAFV600E melanoma cell survival and proliferation.
Assuntos
Sistema de Sinalização das MAP Quinases/genética , Melanoma/genética , Fosfatidilinositol 3-Quinases/genética , Proteínas Proto-Oncogênicas B-raf/genética , RNA Longo não Codificante/genética , Neoplasias Cutâneas/genética , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/genética , Perfilação da Expressão Gênica/métodos , Regulação Neoplásica da Expressão Gênica , Humanos , Melanoma/metabolismo , Melanoma/patologia , Mutação de Sentido Incorreto , Fosfatidilinositol 3-Quinases/metabolismo , Interferência de RNA , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologiaRESUMO
Mitochondrial dysfunction is regarded as a hallmark of cancer progression. In the current study, we evaluated mitochondrial genome instability and copy number in colorectal cancer using Next Generation Sequencing approach and qPCR, respectively. The results revealed higher levels of heteroplasmy and depletion of the relative mtDNA copy number in colorectal adenocarcinoma. Adenocarcinoma samples also presented an increased number of mutations in nuclear genes encoding proteins which functions are related with mitochondria fusion, fission and localization. Moreover, we found a set of mitochondrial and nuclear genes, which cooperate in the same mitochondrial function simultaneously mutated in adenocarcinoma. In summary, these results support an important role for mitochondrial function and genomic instability in colorectal tumorigenesis.