This link has been bookmarked by 1 people . It was first bookmarked on 28 Mar 2007, by Jim Kling.
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28 Mar 07
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TAPET® : Tumor Amplified Protein Expression Therapy, is a modified Salmonella vector used to deliver anticancer agents directly to tumors.
Q. What is TAPET® and how does it work?
A: TAPET® is live attenuated Salmonella bacteria that has been shown in animal studies to selectively accumulate in tumor tissue over normal tissue. Vion seeks to employ TAPET® technologies as a means of delivering anticancer therapy directly to tumors.Q. Why and how does TAPET® accumulate in tumors?
A: The TAPET® bacteria move throughout the body but are generally destroyed by the immune system as they move through normal body tissue. Once they penetrate a tumor, however, tumor-produced substances are thought to inhibit the immune system, thereby permitting replication and accumulation of the bacteria. Tumors also have areas of rapid cell turnover and low oxygen tension, which provide nutrients and favorable growth conditions for the bacteria. TAPET® bacteria will replicate in the tumor by doubling every 30 to 40 minutes, growing to about 100 million to1 billion bacteria per gram of tumor tissue. This represents 1000-fold or more greater concentration of bacteria in tumors compared to normal tissues.
Q. How will TAPET® treat cancer?
A: Conventional cancer treatments are limited by the amount of drug that reaches the tumor, and by the toxicities of the drug, since normal tissues are exposed to similar or higher concentrations of drug than tumor tissue. Therefore, the cancer drug must be given intermittently to allow normal tissues to recover, but during this interval the tumor also recovers from the effects of the cancer drug. The accumulation of TAPET® bacteria in tumor, and the much higher numbers of bacteria in tumor compared to normal tissue, suggests that any cancer fighting agent produced by the bacteria will also be at much higher concentrations in the tumor compared to normal tissue. Furthermore, because the bacteria remain in the tumor for prolonged periods, the delivery of the cancer-fighting agent is continuous.
Vion scientists are taking advantage of the high numbers of bacteria that accumulate in tumors by engineering the bacteria to produce cancer-fighting substances. These armed bacteria have already been shown to produce large amounts of a cancer-fighting substance in animal tumors.
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