The Expression of Heme Oxygenase-1 in Human-Derived Cancer Cell Lines

Background: Heme oxygenase-1 (HO-1) is a cytoprotective and antiapoptotic enzyme, which has been involved in maintaining cellular homeostasis, and plays an important protective role by modulating oxidative injury. Up-regulation of (HO-1) has contributed to tumorogenicity of some cancers. In this study we investigated the expression pattern of the HO-1, in five different human-derived cancer cell lines with high incidence in Iran. Methods: Total cell RNA were extracted from HepG2 (hepato carcinoma), A549 (lung adenocarcinoma), MCF-7 (breast cancer), K562 (myeloid leukemia) and LS174T (colon cancer) cell lines. Human embryonic kidney (HEK293) cell line was used as a control. cDNAs were synthesized and expression of HO-1 was examined using RT-PCR. Results: The expression of HO-1 was not detected in the control cell line (HEK293), but it was observed to express following ultraviolet (UV) exposure indicating that HO-1 is not constantly expressed. The examined cancer cell lines constitutively expressed different variety of HO-1 on mRNA level. Strong expression of HO-1 was observed in HepG2, MCF-7 and A549 cells. A moderate expression of HO-1 was observed in K562 cells, and LS174T cells showed no expression of HO-1. Conclusion: Heme oxygenase-1 could be considered as a new marker in the diagnosis of some cancers, especially hepatomacarcinoma. Our results also suggest that up-regulation of HO-1 may contribute to tumorogenicity of some cancers. Therefore, the combination of gene-silencing effect of HO-1 and chemo-therapy might be considered as a new modality for the treatment of cancers in which the expression HO-1 is up-regulated.