The cytoskeleton plays a key role in regulating many cellular functions; it maintains cell shape, protects the cell, enables cellular motion, and has important roles in proliferation and differentiation. Metastasising cancer cells exploit the cytoskeleton to produce protrusions that allow them to invade surrounding tissue and enter the blood system from where they can spread to distant tissues and seed new tumours.
The protrusions, known as pseudopodia, are highly specialised ‘feet’ that the cell uses to pull itself forward across the underlying surface. A team led by researchers at the University of California, San Diego has now identified a previously unknown kinase – termed pseudopodium-enriched atypical kinase one or PEAK1 – that regulates the cytoskeleton and plays a central role in the formation of pseudopodia. Preliminary studies in mice suggest that PEAK1 is important during tumour growth and the team also showed that PEAK1 levels are increased in primary and metastatic samples from human colon cancer patients. Whether PEAK1 is capable of transforming non-tumour cells into cancer cells has not yet been determined but the fact that PEAK1 has kinase activity suggests that it may be possible to design specific inhibitors which could help to elucidate its role in both normal and cancer cells. PEAK1, which is a 190-kDa non-receptor tyrosine kinase, could serve as a clinical biomarker that predicts whether a cancer is likely to metastasise and could also be a target for future cancer treatments.
The study is published in the Early Edition of the Proceedings of the National Academy of Sciences.