Significance: Prostate and ovarian cancers are major contributors to cancer-related deaths worldwide. Recently, inflammation and nitrosative stress have been implicated in carcinogenesis, with the overexpression of NOS2 and concomitant release of nitric oxide (NO) associated with cancer initiation and progression. Recent Advances: An increasing body of evidence indicates an association between NOS2 expression and aggressive ovarian cancer. Research also indicates a role for NO in prostate disease pathology and prostate cancer. A therapeutic role for NOS2 inhibition and/or NO drugs exists for the treatment of both ovarian and prostate tumors.
Critical issues: Herein, we review the key molecular effects associated with NOS2 in ovarian and prostate cancer. NOS2 increases angiogenesis and tumor proliferation and correlates with aggressive type II ovarian tumors. NOS2 expressing tumors are sensitive to cisplatin chemotherapy, and NO may be used to sensitize cisplatin-resistant tumors to chemotherapy. NOS2 is highly expressed in prostate tumors compared to non-neoplastic prostate pathologies. NO may play a role in the development of androgen-independent prostate cancer via s-nitrosylation of the androgen receptor. Moreover, NOS2 inhibitors and NO donor drugs show therapeutic potential in ovarian and prostate cancer as single agents or dual drugs, by either inhibiting the effects of NOS2 or increasing NO levels to induce cytotoxic effects.
Future directions: NOS2 and NO present new targets for the treatment of ovarian and prostate tumors. Furthermore, understanding NO-related tumor biology in these cancers presents a new means for improved patient stratification to the appropriate treatment regimen. Antioxid. Redox Signal. 26, 1078-1090.
Keywords: inflammation; nitric oxide; ovarian cancer; prostate cancer; therapeutics.