Abstract
Abstract Objective: Cancer stem cells possess the important property of self-renewal. Telomerase activity (TA) is often used as a molecular marker for cancer aggressiveness and allows propagation of cancer cells by adding telomere repeats which can result in unlimited cell replication. As such, the potential of telomerase in maintaining self-renewal properties of cancer stem cells have been proposed. Our objectives were to determine the TA of ovarian cancer stem cells (OSC) and the effectiveness of targeting telomerase for cancer therapy. Methods Ovarian cancer cell lines (ES2, TOV112D, and SKOV3) were grown in non-adherent growth conditions to form spheroid forming cells for numerous successive spheroid generations. Flow cytometry determined the CD44+/CD24- phenotype consistent with cancer stem-cells. Histologic subtypes were chosen to correspond to decreasing levels of aggressiveness: ES2- clear cell; SKOV3- papillary serous; and TOV112D- endometrioid. TRAPEZE RT Telomerase Detection Kit utilized flourescently labeled primers to detect and quantify telomerase activity by RT-PCR. Results were confirmed with luciferase reporter plasmid containing promoter of human telomerase reverse transcriptase (hTERT). Each cancer cell line was treated with 10, 20, 50, and 100uM of a small molecule telomerase inhibitor BIBR1532 measured by cell proliferation survival assay for a total of 72 hours. Results All ovarian cancer cell lines readily formed spheroids in non-adherent growth conditions with flow cytometry demonstrating the enrichment of cancer stem cell phenotype: CD44+/CD24-. TA was significantly increased in spheroid forming cells enriched for OSC in both ES2 (5-fold increase) and SKOV3 (6-fold increase) (p < 0.001), however TOV112D showed a decrease in TA. Similarly, ES2 and SKOV3 showed significant TA by luciferase assay with 400% and 1,700%, respectively (p < 0.001), while TOV112D had a decrease in TA. In all cell lines studied, treatment with BIBR1532 demonstrated significant cell death in a dose-dependent fashion with a 5-fold cell kill and only 20% of cancer cell survival at 72 hours. Conclusions Telomerase activity appears to increase with ovarian cancer stem cells and supports the hypothesis that it could be important in the self-renewal properties of cancer stem cells. Inhibition of telomerase with a competitive small molecule demonstrated significant response in-vitro and could represent novel targeted therapy for ovarian cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3334.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call