A new compound could one day help alleviate the severe side effects of cancer treatment for some people. In Science today , the researchers report that a small organic chemical protects mice against lethal doses of radiation.
Chemotherapy and radiotherapy not only kill tumor cells, they also damage healthy tissue and cause anemia, infections, vomiting, diarrhea and other problems. These side effects can be so severe that they prevent patients from receiving effective treatment. Although some compounds help protect healthy tissue cancer therapies, they have only limited effects, such as helping to restore the ability of the bone marrow to produce red blood cells.
Now, capitalizing on their knowledge of p53 , a powerful tumor suppressor gene, a team led by Andrei Gudkov of the University of Illinois, Chicago, may have found a best way to relieve side effects in some patients. Previous findings have shown, for example, healthy tissue from normal mice suffer more gamma radiation than do normal tissues of mice deficient in p53. This meant that the blocking p53 may prevent side effects -. But only if it could be done without triggering the formation of additional tumors
The team designed a system of cultured cells which could be used to screen rapidly for compounds that block this activation. And 10,000 synthetic chemicals, particularly one looked promising: pifithrin- a (PFT a ). It blocks cell death triggered by radiation and four chemotherapy drugs and it also inhibits the growth arrest induced by radiation. "Surprisingly," said Gudkov, "a single injection saved [normal] mouse completely" from a radiation dose that usually kills 60% of animals, while having no effect on p53-deficient animals. Further, the treated mice survived more than 8 months - about half the normal mouse lifespan - and none developed tumors
Before such a compound can be used in the clinic, Longer. -TERM animal studies are needed to ensure that the drugs do not cause the formation of tumors or have other dangerous side effects, warns medical oncologist Ronald Bukowski, Director of Experimental Therapeutics at the Cleveland Clinic. And people whose tumors contain p53 active gene - true for 50% of cancers - will not do be eligible for the drug, because it could help fight their tumors therapy. But if the new compounds pan out in humans, it would be good news for cancer patients.
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