RESUMO
The BRAF inhibitors vemurafenib and dabrafenib can be used to treat patients with metastatic melanomas harboring BRAFV600 mutations. Initial antitumoral responses are often seen, but drug-resistant clones with reactivation of the MEK-ERK pathway soon appear. Recently, the secretome of tumor-derived extracellular vesicles (EVs) has been ascribed important functions in cancers. To elucidate the possible functions of EVs in BRAF-mutant melanoma, we determined the RNA content of the EVs, including apoptotic bodies, microvesicles, and exosomes, released from such cancer cells after vemurafenib treatment. We found that vemurafenib significantly increased the total RNA and protein content of the released EVs and caused significant changes in the RNA profiles. RNA sequencing and quantitative PCR show that cells and EVs from vemurafenib-treated cell cultures and tumor tissues harvested from cell-derived and patient-derived xenografts harbor unique miRNAs, especially increased expression of miR-211-5p. Mechanistically, the expression of miR-211-5p as a result of BRAF inhibition was induced by increased expression of MITF that regulates the TRPM1 gene resulting in activation of the survival pathway. In addition, transfection of miR-211 in melanoma cells reduced the sensitivity to vemurafenib treatment, whereas miR-211-5p inhibition in a vemurafenib resistant cell line affected the proliferation negatively. Taken together, our results show that vemurafenib treatment induces miR-211-5p up-regulation in melanoma cells both in vitro and in vivo, as well as in subsets of EVs, suggesting that EVs may provide a tool to understand malignant melanoma progression.
Assuntos
Vesículas Extracelulares/metabolismo , Indóis/farmacologia , Melanoma/genética , MicroRNAs/metabolismo , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Neoplasias Cutâneas/genética , Sulfonamidas/farmacologia , Animais , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos , Vesículas Extracelulares/efeitos dos fármacos , Vesículas Extracelulares/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Melanoma/tratamento farmacológico , Melanoma/patologia , Camundongos Endogâmicos NOD , MicroRNAs/genética , Fator de Transcrição Associado à Microftalmia/genética , Fator de Transcrição Associado à Microftalmia/metabolismo , Mutação , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas B-raf/genética , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/patologia , Regulação para Cima/efeitos dos fármacos , Vemurafenib , Ensaios Antitumorais Modelo de Xenoenxerto , Melanoma Maligno CutâneoRESUMO
This corrects the article DOI: 10.1038/cddis.2017.383.