TRP Channels and Small GTPases Interplay in the Main Hallmarks of Metastatic Cancer

Transient Receptor Potential (TRP) cations channels, as key regulators of intracellular calcium homeostasis, play a central role in the essential hallmarks of cancer. Among the multiple pathways in which TRPs may be involved, here we focus our attention on the ones involving small guanosine triphosphatases (GTPases), summarizing the main processes associated with the metastatic cascade, such as migration, invasion and tumor vascularization. In the last decade, several studies have highlighted a bidirectional interplay between TRPs and small GTPases in cancer progression: TRP channels may affect small GTPases activity via both Ca(2+)-dependent or Ca(2+)-independent pathways, and, conversely, some small GTPases may affect TRP channels activity through the regulation of their intracellular trafficking to the plasma membrane or acting directly on channel gating. In particular, we will describe the interplay between TRPC1, TRPC5, TRPC6, TRPM4, TRPM7 or TRPV4, and Rho-like GTPases in regulating cell migration, the cooperation of TRPM2 and TRPV2 with Rho GTPases in increasing cell invasiveness and finally, the crosstalk between TRPC1, TRPC6, TRPM8, TRPV4 and both Rho- and Ras-like GTPases in inducing aberrant tumor vascularization.