Tumor :: A little more PDGF-BB, a little less tumor growth

The formation of new blood vessels (angiogenesis) is essential to provide nutrients to growing tumors.

In the past, some researchers have hypothesized that the growth factor PDGF-BB (platelet-derived growth factor BB) contributes to tumor growth and spread by enhancing the envelopment of newly formed vessels with stabilizing pericytes, and rendering new vessels more resistant to anti-angiogenic therapies.

In a surprising study appearing online on July 19 in advance of publication in the August print issue of the Journal of Clinical Investigation, a team led by Lee Ellis from The University of Texas MD Anderson Cancer Center found that when PDGF-BB was overexpressed in gastrointestinal cancer cells in the lab and then injected into mice, tumor growth was actually inhibited.

In additional studies they treated PDGF-BB?overexpressing tumors with the drug imatinib mesylate (also known as Gleevec), which inhibits the PDGF-BB receptor, and this resulted in reduced pericyte content and increased tumor growth compared to tumors left untreated. They believe that these effects are due to an increased number of pericytes in the tumor, which can actually limit tumor angiogenesis, and in turn limit tumor growth. The authors conclude that the use of drugs that specifically target the PDGF receptor must therefore be used with caution for the treatment of tumors in which the PDGF receptor is not the target on the tumor cell itself.

TITLE: Overexpression of PDGF-BB decreases colorectal and pancreatic cancer growth by increasing tumor pericyte content

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