If we made arobot portrait of a metastatic cancer cell, that is, from a cell that has spread from its place of origin to other parts of the body where it can give rise to a new tumor, its most distinctive feature would be itsability to pass through blood vessel walls. Scientists at the University of Zurich have shown that, at least in part, such a “superpower” is conferred by a protein called CCL2. This tricks and manipulates the receptors or molecular gatekeepers of the endothelium – tissue that lines the interior of arteries, veins and capillaries – to open their doors to the blood. Elevated levels of the CCL2 chemokine are characteristic, especially, of metastases arising from cancers of the breast, prostate, and intestine.
Furthermore, researchers at the University of Arizona have concluded thatinvading cells have structures called invadopodia, a kind of bumps or feet that allow them to pass from one organ to another, opening gaps in the tissues. It is as if they set up a tent: after projecting a portion of their rigid internal scaffolding towards the cell membrane, they extend a long and thin protrusion towards the extracellular matrix – the medium in which the cells are immersed – that would help them to move.
Another of their characteristic features is how little it costs them to make friends. In fact, scientists have found thatThey have more cronies infiltrated into our body than we imagined; among them, platelets. Biologists from the Massachusetts Institute of Technology (MIT) found that this component of the blood, responsible for wound healing, is also secretly responsible for helping malignant cells to grow, to cross the partitions of the vessels, to navigate the torrent blood and to settle in new tissues.
