Progress in the application and mechanism of metformin in treating non-small cell lung cancer

At present, the incidence and mortality of lung cancer demonstrate an increasing trend. Non-small cell lung cancer (NSCLC) accounts for ~80-85% of all lung cancer cases. Therefore, developing novel and more effective treatments is of great importance. The use of combination therapies, where several anticancer agents are used together, is a promising strategy. Recent studies demonstrate that metformin, which has been utilized for treating diabetes mellitus for >50 years, has antitumor effects in numerous types of cancer including NSCLC. Its antitumor effects can be direct and indirect, and it is able to synergize with other physical therapies including targeted anticancer therapy, chemotherapy and radiotherapy. The present review discusses how metformin affects cellular energy metabolism in NSCLC, the mechanism of its antitumor action and its synergy with other therapies. Information and analysis are provided in the present review to stimulate further studies on metformin as an adjunct anticancer treatment.