Normally, tissue injury triggers a mechanism in cells that tries to repair damaged tissue and restore the skin to a normal, or homeostatic state. Errors in this process can give rise to various problems, such as chronic inflammation, which is a known cause of certain cancers.
"It has been noted that cancer resembles a state of chronic wound healing, in which the wound-healing program is erroneously activated and perpetuated," says Professor Adrian Krainer of Cold Spring Harbor Laboratory (CSHL). In a paper published today in Nature Structural & Molecular Biology, a team led by Dr. Krainer reports that a protein they show is normally involved in healing wounds and maintaining homeostasis in skin tissue is also, under certain conditions, a promoter of invasive and metastatic skin cancers.
The protein, called SRSF6, is what biologists call a splicing factor: it is one of many proteins involved in an essential cellular process called splicing. In splicing, an RNA "message" copied from a gene is edited so that it includes only the portions needed to instruct the cell how to produce a specific protein. The messages of most genes can be edited in multiple ways, using different splicing factors; thus, a single gene can give rise to multiple proteins, with distinct functions.
The SRSF6 protein, while normally contributing to wound healing in skin tissue, when overproduced can promote abnormal growth of skin cells and cancer, Krainer's team demonstrated in experiments in mice. Indeed, they determined the spot on a particular RNA message - one that encodes the protein tenascin C - where SRSF6 binds abnormally, giving rise to alternate versions of the tenascin C protein that are seen in invasive and metastatic cancers.