July 27, 2005
Chemotherapy 'Bomb' Developed in Cancer WarTopics: Medicine
(A breast cancer cell seen through an electron microscope. Credit: The National Cancer Institute)
The fundamental challenges in cancer chemotherapy are its toxicity to healthy cells and drug resistance by cancer cells. Here's a new technique that uses nanoparticles to create what scientists call a vascular shutdown [Cancer cells (probably like all tissues) secrete substances that promote the formation of new blood vessels - a process called angiogenesis].
Up to now, the big problem has been that if you shut down the blood supply of the tumor it would undergo angiogenisis and create more blood vessels, and, in order to fully destroy the tumor, chemotherapy is needed but "you can't deliver chemotherapy to the tumor if you've destroyed the vessels necessary to deliver the drug. But these problems may have been overcome, at least in mice.
Scientists have developed a cancer drug that kills with James Bond-like stealth. It breaks its way into a cancer cell, seals the exit, cuts off the cell's blood supply, and then detonates a chemotherapy bomb. All that without harming healthy cells. Tests show the crafty drug has safely treated specific cancers and prolonged survival in mice.The researchers used chemotherapeutic drugs that were already available, and created a nanoparticle that's layered like a "Tootsie Pop," which delivers an 'anti-angiogenic' drug while the Tootsie Pop center is made up of a chemotherapeutic drug.
"The fundamental challenges in cancer chemotherapy are its toxicity to healthy cells and drug resistance by cancer cells," said Ram Sasisekharan of MIT's Biological Engineering Division and leader of the research team.
The new technique uses nanoparticles to create what scientists call a vascular shutdown.
"Once the supply lines are cut off, these nanoparticles are trapped in the tumor and you can unleash the chemotherapy agent," Sasisekharan told LiveScience. "These cells die and collapse."
This technique is detailed in the July 28 issue of Nature.
So far, the engineered nanoparticle has proven to shrink tumors only in mice, and although researchers report exciting survival rates of the test subjects (of the mice treated with the nanoparticle drug, 80 percent survived beyond 65 days. Mice treated with the best available existing therapy survived only to 30 days and untreated mice died at 20 days), human trials could be years away.
Posted by Hyscience at July 27, 2005 5:13 PM
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