Curcumin and Lung Cancer: the Role of microRNAs

Background: Lung cancer is one of the most common types of cancer worldwide and is characterized by a poor prognosis, related to both late diagnosis and lack of effective treatments. In the last years, microRNAs (miRNAs) have been demonstrated to have an important role in tumor microenvironment and immune regulation. These RNAs can be categorized into tumor-suppressor genes, such as let-7 family and miR-34, and oncogenes such as miR-221 and miR-222. Curcumin is a bioactive polyphenol that is documented to have promising anticancer activity, and to be well tolerated in humans. Methods: The present review aims to gather available evidence on the involvement of mRNAs in the therapeutic effects of curcumin against lung cancer. Results: The anti-cancer properties of curcumin against lung cancer have been shown in both cellular and experimental models and are mediated by modulation of several molecular targets that regulate the expression of transcription factors, inflammatory cytokines, enzymes, growth factors, receptors, adhesion molecules, antiapoptotic proteins, and cell cycle proteins, leading to cell apoptosis, inhibition of cell proliferation and migration, and also chemo- and radio-sensitization of lung cancer cells. Recent studies have documented that pharmacological effects of curcumin in lung cancer are also mediated by modulation of several miRNAs, such as downregulation of oncogenic miR-21 and upregulation of oncosuppressive miR-192-5p and miR-215. Conclusion: Further studies are necessary to explore this very promising field and the link between regulation of oncogenic and tumor-suppressive miRNAs and putative anti-cancer properties of curcumin.