title: Methylseleninic acid enhances paclitaxel efficacy for the treatment of triple-negative breast cancer.
abstract: A major challenge in breast cancer therapy is the lack of an effective therapeutic option for a particularly aggressive subtype of breast cancer, triple-negative breast cancer. Here we provide the first preclinical evidence that a second-generation selenium compound, methylseleninic acid, significantly enhances the anticancer efficacy of paclitaxel in triple-negative breast cancer. Through combination-index value calculation, we demonstrated that methylseleninic acid synergistically enhanced the growth inhibitory effect of paclitaxel in triple-negative breast cancer cells. The synergism was attributable to more pronounced induction of caspase-mediated apoptosis, arrest of cell cycle progression at the G2/M checkpoint, and inhibition of cell proliferation. Treatment of SCID mice bearing MDA-MB-231 triple-negative breast cancer xenografts for four weeks with methylseleninic acid (4.5 mg/kg/day, orally) and paclitaxel (10 mg/kg/week, through intraperitoneal injection) resulted in a more pronounced inhibition of tumor growth compared with either agent alone. The attenuated tumor growth correlated with a decrease in tumor cell proliferation and an induction of apoptosis. The in vivo study also indicated the safety of using methylseleninic acid in the combination regime. Our findings thus provide strong justification for the further development of methylseleninic acid and paclitaxel combination therapy for the treatment of triple-negative breast cancer.
authors.affiliation: Departments of Structural and Cellular Biology, Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana, United States of America.
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Qi
authors.forename: Xueqi
authors.initials: X
authors.lastname: Fu
authors.forename: Zhenggang
authors.initials: Z
authors.lastname: Xiong
authors.forename: Haitao
authors.initials: H
authors.lastname: Zhang
authors.forename: Steven M
authors.initials: SM
authors.lastname: Hill
authors.forename: Brian G
authors.initials: BG
authors.lastname: Rowan
authors.forename: Yan
authors.initials: Y
authors.lastname: Dong
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000188:drug therapy*; D049109:Cell Proliferation / Q000187:drug effects; D004357:Drug Synergism; D005260:Female; D059565:G2 Phase Cell Cycle Checkpoints / Q000187:drug effects; D006801:Humans; D051379:Mice; D016566:Organoselenium Compounds / Q000494:pharmacology* / Q000627:therapeutic use; D017239:Paclitaxel / Q000494:pharmacology* / Q000627:therapeutic use; D023041:Xenograft Model Antitumor Assays
chemical_list: D016566:Organoselenium Compounds; C008493:methylselenic acid; D017239:Paclitaxel