Adenovirus-mediated truncated Bid overexpression induced by the Cre/LoxP system promotes the cell apoptosis of CD133+ ovarian cancer stem cells

Abstract

Cancer stem cells are a small subset of cancer cells that contribute to cancer progression, metastasis, chemoresistance and recurrence. CD133-positive (CD133+) ovarian cancer cells have been identified as ovarian cancer stem cells. Adenovirus-mediated gene therapy is an innovative therapeutic method for cancer treatment. In the present study, we aimed to develop a new gene therapy to specifically eliminate CD133+ ovarian cancer stem cells by targeting CD133. We used the Cre/LoxP system to augment the selective expression of the truncated Bid (tBid) gene as suicide gene therapy in CD133+ ovarian cancer stem cells. The adenovirus (Ad)-CD133-Cre expressing Cre recombinase under the control of the CD133 promoter and Ad-CMV-LoxP-Neo-LoxP-tBid expressing tBid under the control of the CMV promoter were successfully constructed using the Cre/LoxP switching system. The co-infection of Ad-CMV-LoxP-Neo-LoxP-tBid and Ad-CD133-Cre selectively induced tBid overexpression, which inhibited cell growth and triggered the cell apoptosis of CD133+ ovarian cancer stem cells. The Cre/LoxP system-mediated tBid overexpression activated the pro-apoptotic signaling pathway and augmented the cytotoxic effect of cisplatin in CD133+ ovarian cancer stem cells. Furthermore, in xenograft experiments, co-infection with the two recombinant adenoviruses markedly suppressed tumor growth in vivo and promoted cell apoptosis in tumor tissues. Taken together, the present study provides evidence that the adenovirus-mediated tBid overexpression induced by the Cre/LoxP system can effectively eliminate CD133+ ovarian cancer stem cells, representing a novel therapeutic strategy for the treatment of ovarian cancer.

Ultrasound microbubbles mediated miR-let-7b delivery into CD133+ ovarian cancer stem cells

“…For example, CD133, ALDH1, CD44, and CD117 have been used as OCSCs markers [ 24 ]. Amongst the surface markers, CD133 has been proved to be a reliable marker for OCSCs separation in many studies [ 25 , 26 ]. In our study, the CD133 was used as the OCSC surface marker.…”

Unraveling the journey of cancer stem cells from origin to metastasis

“…Survivin, another anti-apoptotic protein, has been shown to be up-regulated in breast CSCs and to lead to therapeutic resistance of breast CSCs [151]. Targeting Bid, a pro-apoptotic protein, in ovarian CSCs reduced the stemness of these cells, suggesting that Bid is responsible for the elevated stemness in ovarian CSCs [152]. Targeting these pro-apoptotic and anti-apoptotic proteins in CSCs may increase sensitivity of CSCs to drug-mediated cell death.…”

Recent Progress in Gene Therapy for Ovarian Cancer

“…They constructed two recombinant adenoviruses, the first facilitates the expression of the Cre in CD133+ CSCs, which cut-off LoxP sequences from the second, thus allowing the overexpression of tBid, driven by the CMV promoter, in CD133+ CSCs. This system induced the apoptosis and inhibited growth of OCSCs in vitro and in vivo, in addition to increasing the cytotoxic effect of cisplatin [ 130 ]. Furthermore, it has been shown that OCSCs expressed several genes related to primordial germ cells, germinal lineage, and pluripotency, such as Nanog, Oct4 and Sox2; therefore, their involvement in the manifestation of OC is not excluded [ 131 ].…”