When cells become cancerous they signal to the surrounding tissues to increase production of a protein called collagen, which forms a ‘scaffold’ around the tumour that supports the growth and development of the cells.
This creates an area of dense tissue around the tumour giving the appearance of a lump that may be noticed by feeling the affected area. In turn this also switches on a protein called beta-catenin, which activates a cascade of other genes involved in tumour growth.
But as the cancer cells grow and divide within the scaffold they become tightly packed, activating another important pair of proteins called Rho and ROCK, which are often seen at higher levels in solid tumours.
Previously scientists thought these proteins were mainly involved in the ability of tumour cells to spread around the body and invade the surrounding tissues.
But this latest research – from scientists based at Cancer Research UK’s Beatson Institute in Glasgow who collaborated with researchers from the US, Australia and the Netherlands – suggests that in addition Rho and ROCK are also involved in reorganising the inner structure of the cell to help restore the balance so that cells aren’t torn apart as the tumour increases in size.
Professor Michael Olson, who led the study, said: “Collagen is a protein most people probably associate with cosmetic surgery to create fuller, firmer lips. But it’s a major component of our connective tissues and also important in tumour growth.
“We found that that by blocking the signals responsible for triggering collagen production in mice we could actually slow down the growth and development of the tumour.
“This is exciting because it suggests that pinpointing molecules that control collagen production, and developing drugs to specifically target them, could be an effective way of treating many different types of cancer.”
Dr Lesley Walker, Cancer Research UK’s director of cancer information, said: “Feeling a lump is one of the main ways that solid cancers are picked up and this research demonstrates just how important this increased tissue stiffness is in terms of driving tumour growth and development.
“Understanding more about the molecules involved in creating tissue stiffness in tumours could be an important step in developing new drugs effective at halting or slowing tumour growth.”
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Samuel et al. Actomyosin-mediated cellular tension drives increased tissue stiffness and beta-catenin activation to induce interfollicular epidermal hyperplasia and tumour growth, Cancer Cell (2011), DOI: 10.1016/j.ccr.2011.05.008