Effect of Flavopiridol on Cell Cycle, Apoptosis and Biomolecule Structure Changes in Breast Cancer Stem Cells

Abstract

Objective: Cancer stem cells (CSCs) are a small population in cancer, which are responsible for therapeutic resistance, relapse and metastasis. Flavopiridol has antitumor activity against various types of cancer cells. The mechanism of action of flavopiridol on CD44+/CD24- breast CSCs has not yet been fully elucidated. The aim of this study was to evaluate the mechanism of action of flavopiridol on breast CSCs (BCSC) in terms of apoptosis, cell cycle and biomolecular changes. Methods: In human breast cancer, cells with CD44+/CD24-markers were isolated from MCF-7 cell line using flow cytometry. The induction of apoptosis was investigated by Annexin-V. The effect of flavopiridol on cell cycle arrest was determined and the percent of cell populations at G0/G1, S and G2/M cycles were identified. The effect of the drug on three-dimensional cell cultures was investigated using a multicellular tumor spheroid model. In addition, the effect of flavopiridol on biomolecules has been evaluated using Fourier transform infrared (FTIR) spectroscopy, which has recently been used effectively in various scientific fields. Results: Flavopiridol especially induced early apoptosis. Cell cycle analyses revealed that flavopiridol induced cell cycle arrest in G0/G1 phase. Decreased number and diameter of spheroids was observed following flavopiridol treatment. ATR-FTIR data showed that treatment with flavopiridol led to significant changes in nucleic acids. Conclusion: According to the data obtained in this study, flavopiridol exhibits anticancer effects by altering the structure/expression level of nucleic acids and changing cell cycle progression and inducing apoptosis. These finding reveals that flavopiridol can be an effective antitumor agent for the treatment of breast cancer after in vivo and phase studies are completed.