Antitumor activities of an oncolytic adenovirus equipped with a double siRNA targeting Ki67 and hTERT in renal cancer cells

RNA interference has been proven to be a powerful tool for gene knockdown. Our previous study demonstrated that a Ki67 shRNA carried by an adenovirus reduced Ki67 expression. In this study, we constructed novel oncolytic adenoviruses in which the Ki67 core promoter drove expression of the E1A gene. These adenoviruses were equipped with either a Ki67 small interfering RNA (siRNA), a human telomerase reverse transcriptase (hTERT) siRNA or a double siRNA targeting Ki67 and hTERT. We identified the antitumor activities of oncolytic adenoviruses in 3 renal cancer cell lines, human normal renal tube cell HK-2 and also in nude mice bearing KETR-3-xenografted tumors. Our results showed that these oncolytic adenoviruses, especially Ki67-ZXC2-double siRNA, could effectively induce silencing of the Ki67 and hTERT genes, allow efficient viral replication and induce significant apoptosis of renal cancer cells in vitro and in nude mice. We concluded that a dual siRNA mediated by oncolytic virotherapy could be an effective strategy for cancer gene therapy.