Open Access

Quercetin induces caspase-dependent extrinsic apoptosis through inhibition of signal transducer and activator of transcription 3 signaling in HER2-overexpressing BT-474 breast cancer cells

  • Authors:
    • Hye-Sook Seo
    • Jin Mo Ku
    • Han-Seok Choi
    • Youn Kyung Choi
    • Jong-Kyu Woo
    • Minsoo Kim
    • Ilhwan Kim
    • Chang Hyeok Na
    • Hansol Hur
    • Bo‑Hyoung Jang
    • Yong Cheol Shin
    • Seong-Gyu Ko
  • View Affiliations

  • Published online on: May 5, 2016     https://doi.org/10.3892/or.2016.4786
  • Pages: 31-42
  • Copyright: © Seo et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

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Abstract

Flavonoids are assumed to exert beneficial effects in different types of cancers at high concentrations. Yet, their molecular mechanisms of action remain unknown. The present study aimed to examine the effect of quercetin on proliferation and apoptosis in HER2-expressing breast cancer cells. The anti-proliferative effects of quercetin were examined by proliferation, MTT and clonogenic survival assays. The effect of quercetin on expression of apoptotic molecules was determined by western blotting. Luciferase reporter assay was performed to measure signal transducer and activator of transcription 3 (STAT3) transcriptional activity. ELISA assay was performed to measure intracellular MMP-9 levels. Immunocytochemistry was performed to evaluate the nuclear STAT3 level. The results revealed that quercetin inhibited the proliferation of BT-474 cells in a dose- and time-dependent manner. Quercetin also inhibited clonogenic survival (anchorage-dependent and -independent) of BT-474 cells in a dose-dependent manner. These growth inhibitions were accompanied with an increase in sub-G0/G1 apoptotic populations. Quercetin induced caspase-dependent extrinsic apoptosis upregulating the levels of cleaved caspase-8 and cleaved caspase-3, and inducing the cleavage of poly(ADP‑ribose) polymerase (PARP). In contrast, quercetin did not induce apoptosis via intrinsic mitochondrial apoptosis pathway since this compound did not decrease the mitochondrial membrane potential and did not affect the levels of B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (BAX). Quercetin reduced the expression of phospho-JAK1 and phospho-STAT3 and decreased STAT3-dependent luciferase reporter gene activity in the BT-474 cells. Quercetin inhibited MMP-9 secretion and decreased the nuclear translocation of STAT3. Our study indicates that quercetin induces apoptosis at concentrations >20 µM through inhibition of STAT3 signaling and could serve as a useful compound to prevent or treat HER2-overexpressing breast cancer.
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July-2016
Volume 36 Issue 1

Print ISSN: 1021-335X
Online ISSN:1791-2431

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Spandidos Publications style
Seo H, Ku JM, Choi H, Choi YK, Woo J, Kim M, Kim I, Na CH, Hur H, Jang BH, Jang BH, et al: Quercetin induces caspase-dependent extrinsic apoptosis through inhibition of signal transducer and activator of transcription 3 signaling in HER2-overexpressing BT-474 breast cancer cells. Oncol Rep 36: 31-42, 2016.
APA
Seo, H., Ku, J.M., Choi, H., Choi, Y.K., Woo, J., Kim, M. ... Ko, S. (2016). Quercetin induces caspase-dependent extrinsic apoptosis through inhibition of signal transducer and activator of transcription 3 signaling in HER2-overexpressing BT-474 breast cancer cells. Oncology Reports, 36, 31-42. https://doi.org/10.3892/or.2016.4786
MLA
Seo, H., Ku, J. M., Choi, H., Choi, Y. K., Woo, J., Kim, M., Kim, I., Na, C. H., Hur, H., Jang, B., Shin, Y. C., Ko, S."Quercetin induces caspase-dependent extrinsic apoptosis through inhibition of signal transducer and activator of transcription 3 signaling in HER2-overexpressing BT-474 breast cancer cells". Oncology Reports 36.1 (2016): 31-42.
Chicago
Seo, H., Ku, J. M., Choi, H., Choi, Y. K., Woo, J., Kim, M., Kim, I., Na, C. H., Hur, H., Jang, B., Shin, Y. C., Ko, S."Quercetin induces caspase-dependent extrinsic apoptosis through inhibition of signal transducer and activator of transcription 3 signaling in HER2-overexpressing BT-474 breast cancer cells". Oncology Reports 36, no. 1 (2016): 31-42. https://doi.org/10.3892/or.2016.4786