These signals actually protect the fledgling cancer cells long before new blood vessels have grown around the cancer to supply it with a more permanent source of nutrients and oxygen, said the researchers from the Duke Comprehensive Cancer Center.
Their results will be published in the Dec. 19, 2003, issue of the Federation of American Societies for Experimental Biology Journal.
"We've 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," said Duke cancer biologist Mark Dewhirst, Ph.D.
Dewhirst said his findings present a model of the earliest stages of cancer metastasis, and they bolster medicine's latest strategy of blocking blood vessel growth as a means of inhibiting cancer's spread.
Scientists have long known that tumors secrete proteins which promote the growth of new blood vessels to sustain the tumor's continued growth. What they didn't realize is that endothelial cells that line the blood vessels are also releasing signals back to the cancer cells that protect the cancer cells from dying and direct them to grow toward the blood vessel.
In fact, the cancer cells respond to the endothelial cells' messages by elongating and stretching toward the blood vessel in a column formation, their study showed. This change occurs within days after the cancer cells are implanted in the tissue, and long before new blood vessels have begun to form.
"Our data show that blood vessel endothelial cells are involved in cancer survival and growth at a far earlier stage than w
Contact: Becky Levine
Duke University Medical Center