PINK1 and hepatocellular carcinoma: Next, we examined the subcellular localization of COX-2, PINK1, Drp1, and p-Drp1Ser616 in COX-2 overexpressing HCC cells, and observed that overexpression of COX-2 markedly increased the redistribution of COX-2, PINK1, and p-Drp1Ser616 to mitochondria (Figure 3D).