Protective role of heme oxygenase-1 in liver

Heme oxygenase-1 (HO-1) is the rate limiting enzyme in heme catabolism and degrades heme to carbon monoxide, biliverdin, and ferrous iron. HO-1 transcriptional induction occurs in response to multiple forms of chemical, physical stress and cytokines. HO-1 confers cytoprotection by inhibiting apoptosis, oxidative stress, and inflammation. Hepatitis C virus (HCV) is a major cause of cirrhosis and hepatocellular carcinoma. It has been shown that HO-1 induction and HO-1 products interfere with replication of HCV and markedly decreased HCV replication. However, a growing body of evidence indicates that induction of HO-1 may be involved in carcinogenesis and can play a role in the metastasis and growth of tumors. The antioxidant, antiviral activity of HO-1 makes it the cytoprotective enzyme for liver tissue in HCV infection, and induction of HO-1 can be suggested as a future therapeutic approach. However, the role of HO-1 in tumor growth should not be ignored.