Tamoxifen and tranilast show a synergistic effect against breast cancer in vitro.

ABSTRACT

OBJECTIVE: This study was aimed at examining a separate or combined effect of tamoxifen and tranilast drugs on growth and proliferation of breast cancer cells. BACKGROUND: Breast cancer is one of the most common cancers and the second leading cause of cancer death among women worldwide. Tamoxifen is the most widely used anti-estrogen for the treatment of breast cancer. Studies show that a combination therapy with other drugs enhances the activity of tamoxifen. Tranilast is an anti-inflammatory drug. We hypothesize that tranilast plus tamoxifen can work synergistically and help getting better result from this anticancer drug. METHODS: Two breast cancer cell lines, MCF-7 and MDA-MB-231, were treated with graduated concentrations of tamoxifen and tranilast alone or in combination at 24, 48 or 72 hours for MCF-7, and 48 hours for MDA-MB-231 cells. We used the MTT assay and lactate dehydrogenase leakage (LDH) assay to evaluate cell viability and cytotoxicity, respectively. RESULTS: In both ER-positive and ER-negative breast cancer cell lines, the combination of tranilast and tamoxifen was more effective in growth inhibition than single drug exposure. CONCLUSION: We have demonstrated that by means of a synergistic/additive inhibitory effect, tranilast was capable of enhancing the in vitro activity of tamoxifen on breast cancer cell lines. Based on the results obtained in this study, tranilast could be a candidate drug for combination therapy in resistant breast cancer patients (Fig. 9, Ref. 17). KEYWORDS breast cancer, Tamoxifen, Tranilast, LDH release, MTT.