Abstract A06: MicroRNA-195 acts as a tumor suppressor miRNA in human melanoma cells by targeting Prohibitin 1

Abstract

Abstract Melanoma is the most lethal type of skin cancer. Since chemo-resistance is a significant barrier, identification of regulators affecting chemo-sensitivity is necessary in order to create new forms of intervention. Here, we investigate the role of miR-195, its impact on Prohibitin 1 (PHB1) expression, and on chemo-sensitivity in melanoma cells. TCGA-RNAseq data obtained from 341 melanoma patient samples as well as a panel of melanoma lines were used in an expression correlation analysis between PHB1 and predicted miRNAs. miR-195 impact on PHB1 mRNA and protein levels and relevance of this regulation were investigated in UACC-62 and SK-MEL-5 melanoma lines by qRT-PCR and Western blot, luciferase reporter, and rescue experiments. Cell proliferation, hypodiploid, and caspase 3/7 assays were performed to investigate the potential action of miR-195 as chemo-sensitizer in melanoma cells treated with cisplatin and temozolomide. Analysis of the TCGA-RNAseq revealed a significant negative correlation (Pearson) between miR-195 and PHB1 expression. Moreover, qRT-PCR data showed that miR-195 is downregulated while PHB1 is upregulated in a collection of melanoma lines. We demonstrated that miR-195 regulates PHB1 directly by qRT-PCR and Western blot in melanoma cells and luciferase assays. To establish PHB1 as a relevant target of miR-195, we conducted rescue experiments in which we showed that PHB1 transgenic expression could antagonize the suppressive effect of miR-195 on the proliferation of melanoma cells. Finally, transfection experiments combined with drug treatments performed in the UACC-62 and SK-MEL-5 melanoma cells corroborated miR-195 as a tumor suppressor and potential chemo-sensitivity agent. Citation Format: Priscila D. R. Cirilo, Bruna R. S. Côrrea, Mei Qiao, Luciana N. S. Andrade, Roger Chammas, Luiz O. F. Penalva. MicroRNA-195 acts as a tumor suppressor miRNA in human melanoma cells by targeting Prohibitin 1 [abstract]. In: Proceedings of the AACR International Conference held in cooperation with the Latin American Cooperative Oncology Group (LACOG) on Translational Cancer Medicine; May 4-6, 2017; São Paulo, Brazil. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(1_Suppl):Abstract nr A06.