KRas-ERK signalling promotes the onset and maintenance of uveal melanoma through regulating JMJD6-mediated H2A.X phosphorylation at tyrosine 39

Abstract

Since DNA damage is a first incident occurred during a tumour attack, it is rational that histone H2A.X phosphorylation on tyrosine 39 (H2A.X^Y39ph) may act as a tumour-relevant factor. This study was aimed to test the authenticity of the hypothesis. Uveal melanoma MP65 cells were transfected for expression of KRas mutated. H2A.X phosphorylation and ERK1/2 was measured, and transwell experiment was performed to examine the consequents of H2A.X^Y39ph on MP65 cells developing and migration. Regulatory relationship between H2A.X^Y39ph and ERK1/2 downstream genes were measured. Moreover, whether JMJD6 and MDM2 are involved in H2A.X phosphorylation was studied. Mutation of Ras activated ERK1/2 signalling and inhibited H2A.X phosphorylation at Y39. Silence of H2A.X^Y39ph contributed to the regulation of MP65 cells growth, migration and transcription of ERK1/2 downstream genes, including CYR61, IGFBP3, WNT16B, NT5E, GDF15 and CARD16. The repressed H2A.X phosphorylation through Ras-ERK1/2 signalling might be through MDM2-mediated JMJD6 degradation. Our study suggested that Ras-ERK1/2 signalling inhibited H2A.X phosphorylation at Y39, which led to the uncontrolled developing and migration of uveal melanoma cells. In addition, H2A.X phosphorylation was mediated possibly through JMJD6 which could be degraded by MDM2.

Keywords: H2A.XY39ph; JMJD6; K-Ras-ERK signalling; MDM2; Uveal melanoma.