Mutant Bik expression mediated by the enhanced minimal topoisomerase IIα promoter selectively suppressed breast tumors in an animal model

Abstract

To ensure the success of systemic gene therapy, it is critical to enhance the tumor specificity and activity of the promoter. In the current study, we determined that topoisomerase IIa promoter is selectively activated in breast cancer cells. An element containing an inverted CCAAT box (ICB) was shown to be responsible for the breast cancer specificity. When the ICB-harboring topoisomerase IIa minimal promoter was linked with an enhancer sequence from the cytomegalovirus immediate early gene promoter (CMV promoter), this composite promoter, CT90, exhibited activity comparable to or higher than the CMV promoter in breast cancer cells in vitro and in vivo, yet expresses much lower activity in normal cell lines and normal organs than the CMV promoter. A CT90-driven construct expressing BikDD, a potent proapoptotic gene, was shown to selectively kill breast cancer cells in vitro, and to suppress mammary tumor development in an animal model of intravenously administrated, liposome-delivered gene therapy. Expression of BikDD was readily detectable in the tumors but not in the normal organs (such as heart) of CT90-BikDD-treated animals. The results indicate that liposomal CT90-BikDD is an effective systemic breast cancer-targeting gene therapy.

Adenovirus 5 E1A enhances histone deacetylase inhibitors-induced apoptosis through Egr-1-mediated Bim upregulation

“…In the ovarian cancer model, we intraperitoneally inoculated mice with SKOV3-ip1-luciferase stable cells; tumor formation, growth and reduction were monitored by a bioluminescent imaging system as described previously (Day et al , 2006; Xie et al , 2007). Under the conditions, in which each single treatment did not suppress tumor growth at the respective doses, tumor growth was readily suppressed by the combination treatment (Figure 3a).…”

Down-Regulation of C9orf86 in Human Breast Cancer Cells Inhibits Cell Proliferation, Invasion and Tumor Growth and Correlates with Survival of Breast Cancer Patients

“…MDA-MB-468 breast cancer cell line was kindly provided by Dr. Xiao-Ming Xie (Sun Yat-sen University Cancer Center, Guangzhou, China) [30], [31], [32]. The breast cancer cell lines (MCF-7, MDA-MB-231, MDA-MB-453, MDA-MB-468, and SK-BR-3) were cultured in DMEM with 10% fetal bovine serum (Invitrogen, Carlsbad, CA, USA).…”

A novel hTERT promoter–driven E1A therapeutic for ovarian cancer

“…To determine promoter activities, cells were transiently co-transfected by DOTAP:cholesterol liposomes (42, 44, 45) complexed with 1 µg plasmid and 0.1 µg pRL-TK (internal control) in 12-well plate as previously described (26). After incubation at 37°C with 5% CO 2 for 48 hours, cells were lysed using passive lysis buffer, and luciferase expression was detected by the Dual-Luciferase ® Reporter Assay kit according to the commercial protocol (Promega, Madison, WI).…”