KAEMPFEROL, A FLAVONOID COMPOUND FROM GYNURA MEDICA INDUCED APOPTOSIS AND GROWTH INHIBITION IN MCF-7 BREAST CANCER CELL

Abstract

Background: Kaempferol, a natural flavonoid, has been shown to induce cancer cell apoptosis and cell growth inhibition in several tumors. Previously we have conducted a full investigation on the chemical constituents of Gynura medica, kaempferol and its glycosides are the major constituents of G. medica. Here we investigated the growth inhibition and apoptosis induction effect of kaempferol extracted from G. medica.

Materials and methods: The inhibition effects of kaempferol were evaluated by MTS assay and soft agar colony formation assay. Fluorescence staining and western blotting were be used to study the apoptosis. The structure was identified by ¹H- NMR), ¹³C-NMR and ESI-MS analyses.

Results: Our results showed that kaempferol's inhibition of MCF-7 breast cancer cell growth may through inducing apoptosis and downregulation of Bcl2 expression.

Conclusion: Kaempferol is a promising cancer preventive and therapeutic agent for breast cancer. List of non-standard abbreviations: MTS: 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, HPLC: High-performance liquid chromatography, NMR: Nuclear Magnetic Resonance, ESI-MS Electrospray Ionization Mass Spectral, PARP: Poly ADP-ribose polymerase.

Keywords: Apoptosis; Breast Cancer; Kaempferol.

Figure 1

Chemical structures of the kaempferol

Figure 2

Kaempferol inhibited cell proliferation in MCF-7 cells. MCF-7 cells were exposed to different concentration of kaempferol and then kaempferol was removed from culture media and cultured for an additional 5 days. Data represent mean normalized optical densities ± SEM of 3 trials, *at least p < 0.05, ***at least p < 0.001 vs control, Student’s t-test.

Figure 3

Kaempferol inhibited the colony formation capacity in MCF-7 in a does-dependent manner. Representative photograph of colony was shown on the left, statistical analysis was shown on the right. MCF-7 cells treated with indicated concentration of kaempferol were plated in 0.3% agrose, and colonies were counted 3 weeks lates. *at least p < 0.05, ***at least p < 0.001 vs control.

Figure 4

Apoptosis induced by kaempferol in MCF-7 cells. MCF-7 cells treated with indicated concentration of kaempferol for 24 h and immunostained with DAPI. Apoptotic cells were indicated by arrow.

Figure 5

Apoptosis induced by kaempferol in MCF-7 cells. Western blot analysis of PARP, Bcl2, Bax in MCF-7 cells treated with treated with indicated concentration of kaempferol for 24 h.