MedicalResearch.com Interview with: Benedikt Warth, PhD, Assistant Professor Department of Food Chemistry and Toxicology University of Vienna Vienna, Austria  MedicalResearch.com: What is the background for this study? Response: The palbociclib/letrozole combination therapy was granted accelerated approval by the U.S. Food and Drug Administration in 2015 after a clinical trial showed it doubled the progression-free survival time in postmenopausal women with estrogen receptor (ER) positive, metastatic breast cancer. Letrozole blocks the production of estrogen, thus reducing the growth-promoting stimulation of ERs on breast cancer cells. Palbociclib blocks a different signaling pathway to impede cell division. The combination is now one of the standard therapies for ER-positive breast cancers. The aim of our study was twofold: Firstly, we investigated the drugs synergism at the metabolome level in MCF-7 cells to unravel the unknown underlying metabolic effects of palbociclib/letrozole mechanism of action. We used a global metabolomics approach to analyze the effects of palbociclib and letrozole individually and in combination on breast cancer cells. Metabolomics studies detail cells’ metabolomes—populations of metabolites, the small-molecule end products of cellular processes. Secondly, we aimed at deciphering the impact of the two model xenoestrogens frequently present in our diet, zearalenone and genistein, on this chemotherapy. Since these chemicals interact with the estrogen receptor we hypothesized that they may interfere with the new treatment. (more…)