Study: protects cancer cells

Houston -- U.S. medical scientists say they've discovered a growth factor receptor long known to fuel cancer cell growth, also protects tumor cells.

Researchers at The University of Texas M. D. Anderson Cancer Center said they determined the epidermal growth factor receptor, or EGFR, stabilizes another cell membrane protein that channels a constant supply of glucose to cancer cells, saving them from devouring themselves.

They said their findings might explain why some drugs that block EGFR's activation by its tyrosine kinase activity target have had only limited success.

"We show that the receptor is active independent of its kinase activity," Professor Isaiah Fidler said. "Up until now everyone -- including us -- focused on kinase, kinase, kinase."

The team showed EGFR binds to another cell membrane protein called the sodium/glucose co-transporter, or SGLT1, protecting SGLT1 from destruction by the cell's proteasome complex.

"This complex stabilizes SGLT1 so it continues to transport glucose from the cell membrane into the cell," Professor Mien-Chie Hung said.

The study that included Zhang Weihua, Rachel Tsan, Qiuyu Wu, Wei-Chien Huang and Chao-Hwa Chiu appears in the journal Cancer Cell.

Copyright 2008 by United Press International.