The role of HSP90 in Quercetin-induced apoptosis in human papillary thyroid (B-CPAP) cancer cells

Free Radic Biol Med. 2014 Oct;75 Suppl 1:S43. doi: 10.1016/j.freeradbiomed.2014.10.797. Epub 2014 Dec 10.

Abstract

As in many other cancers, genetic alterations that occur in genes encoding for key proteins of major signalling pathways are the driving force for the tumorigenesis of thyroid cancer. HSP90 is an emerging therapeutic target of interest for the treatment of cancer and is responsible for modulating cellular response to stress by maintaining the function of signalling proteins. In this study, we have worked with B-CPAP, a thyroid papillary cancer cell line which is known to have BRAF V600E mutation. We have administered the flavonoid Quercetin, which is known to induce apoptosis by inhibiting HSP production on various cancer cell lines, at different concentrations (between 10 and 75µM) for 24hours. We have measured cell viability using WST-1 assay. We found that the viability decreases in a dose dependent manner. Then, we chose Quercetin concentrations between 10-75µM for 24hours, for the apoptosis and cell cycle analysis in flow cytometry by Annexin V and propidium iodide. We have also applied Hoechst stain to cancer cells for visualizing them on fluorescence microscopy and confirmed apoptosis with the presence of apoptotic signs in nuclei of cancer cells. Finally, we used Western blotting to compare HSP90 and Cleaved-PARP levels in cells treated with Quercetin and the control group. In the light of the obtained data, our results suggest that in future studies it would be useful to investigate the apoptotic mechanisms of Quercetin and use combinational therapies on BCPAP cells. Supported by Marmara University Scientific Research Commission (SAG-C-TUP-130313-0063).