MicroRNA MIR-204-5P is a regulator of apoptosis in dacarbazine-resistant melanoma cells

FSBEI HE Krasnoyarsk State Medical University named after. prof. V.F. Voino-Yasenetsky Ministry of Health of Russia, Krasnoyarsk,

Russia

Introduction . Therapy for skin melanoma in its disseminated form is ineffective, among other things, due to the development of tumor cell resistance, mediated by various mechanisms. The acquisition of a stable cell phenotype is associated both with genetic and epigenetic changes mediated by the regulatory non-coding microRNA molecules.

The aim hereof is to investigate the ability of mi-croRNA miR-204-5p to influence changes in the cell cycle and apoptosis of melanoma cells resistant to the chemotherapeutic alkylating agent dacarbazine, used in standard chemotherapy for melanoma.

Materials and methods: Cultivation of the SK-MEL-2 melanoma cells (ATCC® HTB-68™), determination of the half-maximal (50%) inhibitory concentration (IC50) based on the colorimetric method for assessing the metabolite 3-(4,5-dimethylthi-azol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), transient transfection into melanoma cells SK-MEL-2 of a synthetic analogue of microRNA miR-204-5p (mimetic), study of cell cycle phases (identification of G0 phase) and detection of cell apoptosis by flow cytometry, immunofluorescence assay, assessment of gene expression by real-time PCR.

Results . Transfection of the microRNA miR-204-5p mimetic into skin melanoma cells exposed to dacarbazine at a concentration of 4xIC50 has resulted in an increase in the share of apoptosis of the latter that confirms the involvement of the studied microR-NA molecule miR-204-5p in the regulation of dacar-bazine-induced apoptosis, but however it has not affected the phases of the cell cycle, in particular, the exit of the G0 phase.

Conclusions . Generally, the results of this study have demonstrated that the microRNA miR-204-5p can influence the resistance of cutaneous melanoma tumor cells to chemotherapeutic drugs, mainly via modulating apoptosis.