SIRT1 and hepatocellular carcinoma: Chen et al. (2011) have demonstrated that knockdown of SIRT1 in hepatocellular carcinoma (HCC) cells inhibited TPP1 expression and induced cellular senescence whereas up-regulated expression of TPP1 in SIRT1-depleted HCC cells improved cellular senescence, strongly suggesting that TPP1 was closely involved in SIRT1-mediated anti-senescence effects in HCC cells.