"There's no dosimetry. People don't wear these radiation badge detectors," said Sharpless. "You'd have to treat everybody."

Currently, if exposed to high levels of radiation, the care right now is supportive and not terribly effective -- giving people antibiotics or growth factors to stimulate blood production, or taking iodine to prevent the thyroid from taking up radioactive material "so you won't get thyroid cancer 14 years from now," Sharpless said.

CANCER TREATMENT

The compounds used in the study are currently undergoing tests by pharmaceutical companies to be used as anti-cancer drugs. About four or five drugs are under review, although Sharpless said the results, so far, are not extremely positive. Most cancers don't require the CDK process to divide, he said. For those that do, while tumors would probably shrink after medication was delivered, he thinks the cancer would quickly rebound. The tumor would likely adapt and learn to grow without the CDK, Sharpless said.

Still, the drug could buy the patient a few more months.

"It's nontoxic, and just a pill. Five months of life for a pill -- you'd do it," Sharpless said.

Even if it's only a stop-gap against cancer, the drug might have other uses in the fight against the disease, namely by protecting patients from chemotherapy side effects.

Chemo, by causing double-strand DNA breaks in rapidly dividing cells, like cancers, also can kill blood-producing bone marrow cells, leading to anemia or dangerously low platelet counts.

By protecting those bone marrow cells, the drugs could make it easier for patients to endure chemo regimens, Sharpless said.

And as only a handful of known cancers use CDK to multiply, researchers would just have to test to make sure the patient wasn't afflicted by one of them. For now, Sharpless is interested in its use with small cell lung cancer, known to not depend on CDK 4 and 6 for replication, he said.

DRUG DEVELOPMENT

Research on the project has now transferred mainly to G-Zero Therapeutics, a company co-founded by Sharpless in 2007.

The work for the current research was partly funded by the National Institutes of Health, as the government has made discovering a countermeasure to radiation sickness a top research priority.

And while it's still some ways away from the clinic, Sharpless said development of the drug will use what is called FDA's two-animal rule. The scientists obviously can't irradiate human volunteers to test whether the drug works in people. Instead, researchers test effectiveness in two animal species.

As for helping to ease the side effects of chemotherapy, Sharpless expects they'll publish a paper on its role in chemotherapy later this year, one of two papers he expects to get out by January, as the team settles down to the nitty-gritty of detailed pharmokinetic research.

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