PTENP1 and melanoma: Based on these reports, we set out to investigate if PTENP1-AS was involved in this process through transcriptional suppression of PTEN. To do this, a series of BRAFi resistant melanoma sublines were obtained by culturing the BRAFi sensitive A375 cell line in increasing doses of BRAFi (A375PR1 (resistant to PLX4720), A375VR3 and A375VR4 (both resistant to vemurafenib))15.