Temple researchers develop drug to block tumors

WHEN IT COMES to stopping cancer, a team of scientists at the Fels Institute for Cancer Research at the Temple University School of Medicine has decided to turn the tables on the disease.

How? By developing a new drug that halts cancer-cell division, effectively killing the tumor cells.

This new and growing area of cancer research is called "targeted therapy." Here's how Temple's version works:

When cancer cells divide and grow, they rely on a molecule called Plk1 to fuel the process. Plk1 is one of several molecules that play a critical role in the spread of cancer. Studies have found that higher levels of Plk1 in cancer tumors result in poorer survival rates.

Led by Dr. Prem Reddy, professor of biochemistry and director of the Fels Institute, the Temple team sought out a new compound or drug that would target and block the Plk1 molecule.

Called ON01910, the new drug shuts down all Plk1 activity and effectively halts cell division. Without Plk1, the cancer tumors can't survive.

"Tumor cells are very rapidly dividing cells," said Reddy, whose works is funded by the National Institutes of Health, the Army, the Susan G. Komen Breast Cancer Foundation and Onconova Therapeutics Inc. When the new drug is introduced, "they are totally disrupted in this process."

The new drug is in the clinical trials for human-cancer therapy, conducted by the Johns Hopkins School of Medicine and Mount Sinai Medical Center in patients with advanced cases of cancer.

Though the drug worked on 94 kinds of cancer when tested in animals, testing in humans represents "a totally different ballgame," said Reddy. "We have to take different types of tumors and see where it works best."

Reddy is excited for several reasons about the ongoing research. For one, the drug appears to block tumor cells from reaching normal cells in three ways: It blocks the invasion of healthy cells; it blocks the growth of surrounding blood vessels, and it kills the tumor cells.

Also, based on his early work in animals, Reddy found that the drug has an "extraordinary safety profile. It can be given in very high doses with little or no side effects. And it works with several existing cancer drugs, often inducing complete regression of tumors."

If the drug proves to be as safe as Reddy thinks it is, a patient could take this drug effectively for a long time - much like patients with leukemia take medications every day.

"We are entering a new phase of cancer treatment," said Reddy. "In the past, however toxic the treatment could be, the idea would be to give a dose of the drug that makes the patient's tumor go away.

"But with this new approach, our goal now in cancer research is to create drugs that reduce cancer to a chronic disease - not a fatal disease." *