"The significance of this fusion toxin is that it's not specific to one kind of tumor it has impressive anti-tumor effects in various kinds of tumors including melanoma and prostate cancers," Dr. Rosenblum said. "We need additional research to determine if it is equally effective in other cancers."
In the mouse study, destruction of the tumor blood vessels was observed as early as 48 hours after administration of the VEGF/rGel. There was no visible damage in any normal organs, including the kidneys, of the treated mice, Dr. Rosenblum said.
VEGF is one of the predominant factors responsible for angiogenesis the ability of a tumor to create new blood vessels to maintain growth and metastasize.
"The receptors for VEGF are overexpressed on the endothelium of tumor vasculature but are almost undetectable in the adjacent normal tissue, so they make excellent targets for the development of therapeutic agents that inhibit tumor growth and metastatic spread by inhibiting the new blood vessel formation," Dr. Rosenblum said.
The researchers chose the genetically engineered toxin gelonin to link to the VEGF "carrier" because it does not appear to be antigenic in human clinical trials conducted thus far at M. D. Anderson, and it does not cause damage to normal blood vessels as do other toxins that have been explored for use in anti-tumor therapies, Dr. Rosenblum said.
Genetically engineered gelonin was developed in a research program at M. D. Anderson, and related intellectual property rights are owned by Research Development Foundation (RDF). RDF is in the process of licensing the gelonin technology for use with various cell-targeting proteins such as growth factors and antibodies.
Therapies that attack tumor blood vessels have recently been a hot area in cancer research because they appear to bypass the major problem with chemother
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Contact: Wayne Carter
wayne.carter@utsouthwestern.edu
214-648-3404
UT Southwestern Medical Center
10-Jun-2002