Biochemical Dialogue Promotes Cancer Cell Growth

Researchers have discovered that a biochemical dialogue takes place between spreading cancer cells and surrounding epithelial tissue that both protects the fledgling tumor cells and encourages them to grow in the direction of newly forming blood vessels.

Investigators at Duke University (Durham, NC, USA; www.duke.edu) studied tumor cell survival and angiogenesis initiation using two mouse tumor lines (4T1 mammary carcinoma and B16 melanoma), which constitutively expressed green fluorescent protein, in dorsal skin-fold window chambers of mice treated with extracellular domain of Tie-2 (ExTek, a soluble protein known to block new blood cell formation) or bFGF (basic fibroblast growth factor, an angiogenesis promoter).

They reported in the December 19, 2003, online edition of the Federation of American Societies for Experimental Biology Journal that ExTek reduced tumor cell survival, retarded tumor growth, and inhibited angiogenesis onset compared with controls. bFGF increased tumor cell survival and promoted earlier angiogenesis and tumor growth. Neither bFGF nor ExTek affected cell proliferation in vitro.

"We have demonstrated a give-and-take relationship in which cancer cells release signals to nearby blood vessels to stimulate new vessel growth, and in turn, blood vessels release signals that sustain the migrating cancer cells as they try to establish themselves in new tissue,” explained senior author Dr. Mark Dewhirst, a professor in the department of radiation oncology at Duke University Medical Center. "Our data show that blood vessel endothelial cells are involved in cancer survival and growth at a far earlier stage than we had originally believed. This discovery energizes our efforts to block these signals from being released and to inhibit new blood vessels from forming.”



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