Brief note on a paper in the August issue of Nature Cell Biology – researchers at the Weizmann Institute in Israel have found how one adaptor protein can be replaced by another related protein, uncoupling the connections between the extracellular matrix (ECM) and the actin cytoskeleton through integrins. This family of gene products, termed tensins, include four known members – tensins-1, -2 and -3 contain integrin-binding PTB domains as well as actin-binding motifs; the fourth family member, termed cten, is shorter and lacks an actin-binding domain.
Katz et al. looked at the expression profiles of these and related proteins as a result of epidermal growth factor (EGF) treatment. They found that tensin-3 and cten were reciprocally regulated by EGF, through induction of expression of one gene or the other. In a commentery in the same issue, Pylayeva and Giancotti offer a the implication of this finding:
does the tensin–cten switch described by Katz et al. contribute to a transition from mesenchymal to amoeboid migration, and could cten-positive tumours be classified as poor candidates for integrin signalling-targeted therapy? Because the authors have not directly assessed the role of the tensin–cten switch in cancer cell migration and invasion, in vitro or in vivo, it remains to be determined whether cten upregulation drives invasion or whether it is just a passive marker.
Well, Katz and colleagues remind us that even if cten is just a passive marker, it could be a powerful tool in determining prognosis and treatment strategies – inhibition of the EGF receptor should lead to a drop in cten expression, lighting the way to a contained (non-invasive) tumor. And the prognosis for a contained tumor is a more rosy one.