Identification of an ataxia telangiectasia-mutated protein mediated surveillance system to regulate Bcl-2 overexpression

The Combinatory Effects of Glabridin and Tamoxifen on Ishikawa and MCF-7 Cell Lines

Estrogen replacement therapy is commonly used to replace the loss of estrogen in post-menopausal women. However, it is not suitable to be used in women taking tamoxifen as both of the drugs increase the risk of endometrial cancer. This project aimed to study the potential of using the natural compound glabridin in combination with tamoxifen as a drug for estrogen replacement therapy. Ishikawa and MCF-7 cells were used to investigate the estrogenic activities stimulated by the combination of tamoxifen and glabridin through ALP and MTT assays. The expressions of the ESR1 and bcl-2 genes have also been determined using RT-PCR. The results indicated that the combination of 1×10−5M tamoxifen and 1×10−6M glabridin exhibited estrogenic activities and suppressed cell growth in both cell lines. The relative expressions of ESR1 and bcl-2 genes indicated that the estrogenicity expressed by the combinatory drug was regulated by estrogen receptor α; however, the reduction in cell proliferation was not modulated by bcl-2 anti-apoptotic proteins. These results suggested that the combination of tamoxifen and glabridin has potential to be used as an estrogen replacement drug with a reduced risk of endometrial cancer that has arisen from the intake of tamoxifen.

The stem cell factor antibody enhances the chemotherapeutic effect of adriamycin on chemoresistant breast cancer cells

Background

The outcome of chemotherapy in breast cancer is strongly influenced by multidrug resistance (MDR). Several surrogate markers of chemoresistance have been identified including - CD24 (cluster differentiation 24) expression, stem cell growth factor (SCF), B-cell lymphocyte protein 2 (Bcl-2) and annexin V. The present study aimed to examine the expression of CD24 in the sensitive breast cancer cell line MCF-7 (Michigan Foudation-7) and MCF-7/adriamycin resistant (MCF-7/AdrRes) cells, and, if minimal effective doses of the anthracycline drug adriamycin (0.579 μM and 88.2 μM) would be enhanced by the antibody to SCF (anti-SCF).

Methods

CD24 expression was analysed by flow cytometry. Both Bcl-2 and annexin V protein expression were quantitatively assessed by the enzyme-linked immunosorbent assay (ELISA).

Results

In MCF-7/AdrRes cells the expression of CD24 was significantly higher compared to MCF-7 cells, 86.6% and 16.3% (p < 0.001), respectively. Bcl-2 expression was significantly increased in the presence of adriamycin and SCF (p < 0.038) and decreased in the presence of adriamycin and anti-SCF. When adriamycin, anti-SCF and SCF were combined or when adriamycin was used alone the decrease in Bcl-2 expression was insignificantly altered. In the presence of both adriamycin and SCF the expression of annexin V was decreased. However, it was significantly increased in the presence of adriamycin and anti-SCF (p < 0.042), as well as adriamycin, anti-SCF and SCF combined.

In MCF-7 cells the effect of adriamycin alone or with either SCF, anti-SCF or anti-SCF or SCF combined, did not significantly alter the expression of Bcl-2. However, in the presence of both adriamycin and SCF the expression of annexin V was decreased, but was significantly increased in the presence of adriamycin and anti-SCF (p < 0.001), adriamycin, anti-SCF and SCF combined and adriamycin alone. Our results demonstrate that anti-SCF with low dose of adriamycin reduces Bcl-2 expression in MCF-7/AdrRes cells and increases annexin V expression in both MCF7/AdrRes and MCF-7 cells.

Conclusion

Adding anti-SCF to the chemotherapeutic regime of adriamycin may strongly enhance its chemotherapeutic effect in the treatment of patients with breast cancer.