Metabolic alterations in mammary cancer prevention by withaferin A in a clinically relevant mouse model

Abstract

BackgroundEfficacy of withaferin A (WA), an Ayurvedic medicine constituent, for prevention of mammary cancer and its associated mechanisms were investigated using mouse mammary tumor virus-neu (MMTV-neu) transgenic model.MethodsIncidence and burden of mammary cancer and pulmonary metastasis were scored in female MMTV-neu mice after 28 weeks of intraperitoneal administration with 100 g WA (three times/week) (n = 32) or vehicle (n = 29). Mechanisms underlying mammary cancer prevention by WA were investigated by determination of tumor cell proliferation, apoptosis, metabolomics, and proteomics using plasma and/or tumor tissues. Spectrophotometric assays were performed to determine activities of complex III and complex IV. All statistical tests were two-sided.ResultsWA administration resulted in a statistically significant decrease in macroscopic mammary tumor size, microscopic mammary tumor area, and the incidence of pulmonary metastasis. For example, the mean area of invasive cancer was lower by 95.14% in the WA treatment group compared with the control group (mean = 3.10 vs 63.77mm2, respectively; difference =-60.67mm2; 95% confidence interval =-122.50 to 1.13mm2; P =. 0536). Mammary cancer prevention by WA treatment was associated with increased apoptosis, inhibition of complex III activity, and reduced levels of glycolysis intermediates. Proteomics confirmed downregulation of many glycolysis-related proteins in the tumor of WA-treated mice compared with control, including M2-type pyruvate kinase, phospho glycerate kinase, and fructose-bisphosphate aldolase A isoform 2.ConclusionsThis study reveals suppression of glycolysis in WA-mediated mammary cancer prevention in a clinically relevant mouse model. © 2013 The Author.