Abstract 967: Vemurafenib regulates miRNA-211 expression in melanoma - effects on extracellular vesicle RNA cargo and function

Abstract

Abstract In melanoma, more than 50% of the patients harbor BRAF somatic missense mutations, most affecting the V600 region. Vemurafenib, a potent BRAF inhibitor used for the treatment of late stage melanoma, has shown promising results by causing programmed cell death in melanoma cells. Recently, extracellular vesicles including apoptotic bodies, microvesicles and exosomes has been shown to contain genetic information especially RNA with distinct repertoire of RNA, which could be transferred from one cell to another. Here we investigate the effects of Vemurafenib on melanoma cells and the RNA content in their subsets of extracellular vesicles. Upon vemurafenib treatment, we found that the melanoma cells harboring the BRAF mutation significantly increases the RNA and protein cargo in the different subsets of extracellular vesicles. The RNA profile also changes substantially in apoptotic bodies and microvesicles with significant changes in the ribosomal RNA ratio. Further, using small RNA sequencing, we found that extracellular vesicles from treated cells harbor unique miRNAs. The significantly different miRNA detected with sequencing analysis was validated in vitro with PCR and confirmed that miR-211 is upregulated in cells as well as subsets of extracellular vesicles after treatment. Furthermore, miR-211 was validated to be significantly upregulated in tumors tissues harvested from patient derived xenograft (PDX) as well as cell line derived xenograft and its vesicular subsets. This shows that vemurafenib induces miR-211 upregulation in BRAF mutant cells and PDX especially in the subsets of extracellular vesicles. miR-211 induction upon oncogene treatment could be potentially used as a biomarker in melanoma patients with BRAF mutation. Citation Format: Taral R. Lunavat, Lesley Cheng, Berglind Einarsdottir, Cecilia Lässer, Jonas A. Nilsson, Andrew F. Hill, Jan Lötvall. Vemurafenib regulates miRNA-211 expression in melanoma - effects on extracellular vesicle RNA cargo and function. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 967.