OPTN and ocular melanoma: More importantly, the H3K9Ac level in OPTN promoter was decreased after metformin treatment (Figure 6G–J, lanes 9 and 10); however, H3K9Ac level largely restored after siSIRT1 (Figure 6F,G, lane 12) and EX527 treatment (Figure 6I,J, lane 12) in ocular melanoma cells.