PTGS2 and hepatocellular carcinoma: Also, NAC reversed phosphorylation of AMPK, PARP cleavage and decreased expression of Bcl-2 and COX-2 in HepG2 cells, demonstrating that LA generates ROS and subsequently induces AMPK phosphorylation, PARP cleavage and inhibits antiapoptotic proteins such as Bcl-2 and COX-2 leading to apoptosis in HCC cells (Figure 7).