EGFR protects cancer cells from starvation via a kinase-independent mechanism

Scientists have uncovered a previously unrealized mechanism by which the epidermal growth factor receptor (EGFR), a tyrosine kinase, promotes survival of cancer cells through a kinase-independent mechanism. The research, published by Cell Press in the May issue of the journal Cancer Cell, provides a rationale for the less than impressive results of recent clinical trials aimed solely at interfering with kinase activity and suggests new directions for potential therapeutic strategies.

The EGFR is closely associated with cell proliferation and survival and excessive expression, and activation of the EGFR is often observed in cancers of epithelial origin. Until now, it was believed that most of EGFR’s functions were mediated by its kinase activity, and several compounds that specifically inhibit the kinase activity of the EGFR were developed with the aim of treating these cancers. However, the clinical experience so far has been that blockade of the EGFR tyrosine kinase activity alone does not elicit significant clinical outcomes in most patients.

“The expression level of EGFR in cancer tissues is correlated with prognosis, but not with responsiveness to EGFR tyrosine kinase inhibitor treatment, suggesting that, independent of its kinase activity, EGFR may contribute to the progression of cancer,” explains study author Dr. Isaiah J. Fidler from the Department of Cancer Biology at The University of Texas M.D. Anderson Cancer Center. Dr. Fidler and colleagues designed a series of studies to investigate the kinase-independent prosurvival function of the EGFR in cancer cells.