Ion channels and transporters in tumour cell migration and invasion.

Cell migration is a central component of the metastatic cascade requiring a concerted action of ion channels and transporters (migration-associated transportome), cytoskeletal elements and signalling cascades. Ion transport proteins and aquaporins contribute to tumour cell migration and invasion among other things by inducing local volume changes and/or by modulating Ca(2+) and H(+) signalling. Targeting cell migration therapeutically bears great clinical potential, because it is a prerequisite for metastasis. Ion transport proteins appear to be attractive candidate target proteins for this purpose because they are easily accessible as membrane proteins and often overexpressed or activated in cancer. Importantly, a number of clinically widely used drugs are available whose anticipated efficacy as anti-tumour drugs, however, has now only begun to be evaluated.