Paper Title
The Anti-Cancer Effects of Β-Lapachone in Tamoxifen-Resistant Breast Cancer Cells

Abstract
This study aimed to investigate the anti-cancer effect of β-lapachone and the underlying mechanisms in endocrine-resistant breast cancer cells. The cytotoxicity of β-lapachone was evaluated by MTT assay in tamoxifen resistant cell line (MCF-7/LCC2) and normal fibroblast cell line (PCS201-010). The protein level of tamoxifen-resistant related gene was assessed by Western blot in MCF-7/LCC2 cells. Our results demonstrated that β-lapachone significantly inhibited the growth of MCF-7/LCC2 and PCS201-010 cells with IC50 values of 2.81 ± 0.46 and 22.10 ± 2.82 µM, respectively. β-lapachone also inhibited Cyclin D1 which is involved in tamoxifen resistance. β-lapachone had anti-cancer effect in tamoxifen-resistant breast cancer cells with less toxicity in normal cells. These results suggested that β-lapachone is a promising anticancer agent for breast cancer patients with tamoxifen resistance. Keywords - Tamoxifen-Resistant Breast Cancer Cells, β-Lapachone, Cyclin D1