REIC/Dkk-3 as a potential gene therapeutic agent against human testicular cancer

Human testicular cancer is very sensitive to chemotherapy and radiation therapy and is regarded as a curable cancer. The cancer prevails in the young reproductive generation and testicular dysfunction is often observed as a side effect, remaining a serious challenge. In the present study, we examined the potential utility of REIC/Dkk-3-based gene therapy against human testicular cancer. Expression of REIC/Dkk-3 was reduced in all of the human seminoma and non-seminomatous germ cell tumor tissues. Overexpression of REIC/Dkk-3 using an adenovirus vector (Ad-REIC) induced apoptosis in a testicular germ cell cancer cell line NCCIT but not in normal human fibroblasts. c-Jun terminal kinase (JNK) was activated by Ad-REIC and the induction of apoptosis was abrogated by a JNK inhibitor. A single intratumoral injection of Ad-REIC markedly inhibited the tumorigenic growth of NCCIT cells in nude mice. These results indicate that Ad-REIC may lead to developing less insulting and non-genotoxic therapeutic measures against human testicular cancer.