New drug agent knocks out multiple enzymes in canc...( A team of 24 researchers from the U....)

A team of 24 researchers from the U.S., Europe, Taiwan and Japan and led by University of Illinois scientists has engineered a new anti-cancer agent that is about 200 times more active in killing tumor cells than similar drugs used in recent clinical trials.

The study appears this week in the Journal of the American Chemical Society.

The new agent belongs to a class of drugs called bisphosphonates. These compounds were originally developed to treat osteoporosis and other bone diseases, but were recently found to also have potent anti-cancer and immune boosting properties.

Drug developers have tried for years to design drugs to inhibit cell survival pathways in tumor cells, focusing on a protein called Ras since nearly a third of all human cancers involve a mutation in the Ras gene that causes cell signaling to go awry. These efforts have met with limited success.

Bisphosphonates act on other enzymes, called FPPS and GGPPS, which are upstream of Ras in the cell survival pathway. Inhibiting these enzymes appears to be a more effective strategy for killing cancer cells.

When used in combination with hormone therapy in a recent clinical trial, the bisphosphonate drug zoledronate significantly reduced the recurrence of breast cancer in premenopausal women with estrogen-receptor-positive breast cancer. Similar results were reported previously for hormone-refractory prostate cancer.

But zoledronate quickly binds to bone, reducing its efficacy in other tissues.

"We're trying to develop bisphosphonates that will be very active but won't bind to the bone, because if they bind to the bone they're not going to go to breast, lung or other tissues," said University of Illinois chemistry professor Eric Oldfield, who led the new study.

Oldfield's team also wanted to design a compound that would inhibit multiple enzymes in the tumor cell survival pathway, rather than just one, an approach analogous
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