Metformin changes the transcriptomic profile to inhibit breast cancer cell growth

Metformin is an easily accessible, widely used drug in diabetes treatment. A central mechanism of its action is the blocking of the mTOR signaling pathway, which has an essential role in regulating metabolic processes, also cell proliferation and survival. The mTOR pathway is not only overstim-ulated in diabetes; blocking it also decreases the growth rate of cancer cells, and induces apoptosis. We intended to study the transcriptomic changes that metformin incurs, therefore - after con-firming its antitumor effect in vitro - we treated MCF-7 cells with three different concentrations of metformin, and sequenced the RNAs isolated from them. We found that the transcriptomic profiles of the treated cells are well distinguishable from the control samples, also the three treatment groups from each other, and three groups of genes are consistently changing: gene expression regulators, stress response genes and cell cycle related genes. The first group obviously indicates that metformin acts on the transcriptomic level too, while the latter two are potentially responsible for the altered growth rate and survival. Our results are in line with similar studies, and although there are further challenges to resolve, like dosage, we believe metformin can be a potential candidate for treating certain types of cancer.