OVA12, a novel tumor antigen, promotes cancer cell growth and inhibits 5-fluorouracil-induced apoptosis

To achieve a better understanding of mechanisms that underlie carcinogenesis and to identify novel target molecules for diagnosis and therapy of carcinoma, we previously identified 24 distinct gene clones by immunoscreening of a cDNA library derived from an ovarian cancer patient through SEREX analysis. Among these genes we focused on a novel gene termed OVA12 and which putatively encodes a 114-amino-acid protein. In the present study, we found that OVA12 was ubiquitously overexpressed in diverse human tumor cell lines. Interestingly, we noticed that overexpression of OVA12 promoted proliferation of cancer cells in vitro and accelerated tumor growth in nude mice as compared to controls. Conversely, specific downregulation of OVA12 inhibited tumor cell proliferation and tumor growth both in vitro and in vivo. Furthermore, OVA12 inhibited 5-FU-induced apoptosis through specific upregulation of Mcl-1 and survivin. These results demonstrate that OVA12 is able to promote tumor growth, suggesting that this antigen might be a new potential target for development of cancer therapy.