TRP channels and cancer: new targets for diagnosis and chemotherapy

The Transient Receptor Potential (TRP) channels family consists of seven different subfamilies, namely TRPC (Canonical), TRPV (Vanilloid), TRPM (Melastatin), TRPML (Mucolipin), TRPP (Polycystin), and TRPA (Ankyrin transmembrane protein) and TRPN (NomPC-like) that are related to several physiological and pathological processes. Recent years have witnessed an increased interest of research into the connection between TRP channels and cancer, leading to the discovery of tumor-related functions such as regulation of proliferation, differentiation, apoptotis, angiogenesis, migration and invasion during cancer progression. Among the TRP families, TRPCs, TRPMs and TRPVs are mainly related to malignant growth and progression. Depending on the type and stage of the cancer, regulation of TRPs mRNA and protein expression have been reported; these changes may regulate ion-dependent cell proliferation and resistance of cancer cells to apoptotic-induced cell death with consequent cancer promoting effects and resistance to chemotherapic treatments. Considerable efforts have been made to fight cancer cells and targeted therapy seems to be the most promising strategy: in this regard, ion channels belonging to the TRP channel superfamily could play an important role. Aim of this review is to summarize data reported so far on the expression and the functional role of TRP channels during cancer growth and progression, and the relationship with clinico-pathological markers. Moreover, the feasibility of TRP channels as target of chemotherapy and the different approaches by which these channels can be targeted will be analyzed in detail. Deeper investigations are required to understand the role TRP channels in cancer in order to develop further knowledge of TRP proteins as valuable diagnostic and/or prognostic markers, as well as targets for pharmaceutical intervention and targeting.