Ca²⁺ Signaling and Hypoxia/Acidic Tumour Microenvironment Interplay in Tumour Progression

This is the authors' abstract. We don't add key points for this paper.

Solid tumours are characterized by an altered microenvironment (TME) from the physi-cochemical point of view, displaying a highly hypoxic and acidic interstitial fluid. Hy-poxia results from uncontrolled proliferation, aberrant vascularization and altered can-cer cell metabolism. Tumour cellular apparatus adapt to hypoxia by altering its metab-olism and behaviour, increasing its migratory and metastatic abilities by acquisition of a mesenchymal phenotype and selection of aggressive tumour cell clones. Extracellular acidosis is considered a cancer hallmark, acting as a driver of cancer aggressiveness by promoting tumour metastasis and chemoresistance by selecting for more aggressive cell phenotypes, although the underlying mechanism is still not clear. In this context, Ca2+ channels represent good target candidates due to their ability to integrate signals from the TME. Ca2+ channels are pH and hypoxia sensors and alterations in Ca2+ homeostasis in cancer progression and vascularization have been extensively reported. The present review will focus on Ca2+ permeable ion channels, with a major focus on TRP, SOC and PIEZO channels, that are modulated by tumour hypoxia and acidosis as well as the role of the resulted altered Ca2+ signals on cancer progression hallmarks. A deeper compre-hension of the Ca2+ signaling and acidic pH/hypoxia interplay will break new ground for the discovery of alternative and attractive therapeutics targets.