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Journal of Thyroid Research
Volume 2016, Article ID 9843675, 10 pages
Research Article

Quercetin-Induced Cell Death in Human Papillary Thyroid Cancer (B-CPAP) Cells

1Department of Biochemistry, School of Medicine, Marmara University, Maltepe, 34854 Istanbul, Turkey
2Genetic and Metabolic Diseases Research Center, Marmara University, Maltepe, 34854 Istanbul, Turkey
3Department of Biochemistry, School of Medicine, Dokuz Eylül University, Inciralti, 35340 Izmir, Turkey

Received 4 September 2015; Revised 16 December 2015; Accepted 22 December 2015

Academic Editor: Gary L. Francis

Copyright © 2016 Ergül Mutlu Altundağ et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In this study, we have investigated the antiproliferative effect of quercetin on human papillary thyroid cancer cells and determined the apoptotic mechanisms underlying its actions. We have used different concentrations of quercetin to induce apoptosis and measured cell viability. Apoptosis and cell cycle analysis was determined by flow cytometry using Annexin V and propidium iodide. Finally, we have measured changes in caspase-3 and cleaved poly(ADP-ribose) polymerase (PARP) protein expression levels as hallmarks of apoptosis and Hsp90 protein expression level as a marker of proteasome activity in treated and control cells. Quercetin treatment of human papillary thyroid cancer cells resulted in decreased cell proliferation and increased rate of apoptosis by caspase activation. Furthermore, it was demonstrated that quercetin induces cancer cell apoptosis by downregulating the levels of Hsp90. In conclusion, we have shown that quercetin induces downregulation of Hsp90 expression that may be involved in the decrease of chymotrypsin-like proteasome activity which, in order, induces inhibition of growth and causes cell death in thyroid cancer cells. Thus, quercetin appears to be a promising candidate drug for Hsp90 downregulation and apoptosis of thyroid cancer cells.