"This kind of approach will give us important clues about the gene regulation in a number of cells in normal and cancer tissue," he says. "It opens new avenues for treatment because these miRNA genes are so small, they can get into cells and be used as drugs. Characterizing their targets might help in understanding cancer phenotypes."

MiRNA genes can function differently. Take miR-16, for example, which is one of the miRNA genes Dr. Croce has studied in CLL. It functions as a tumor suppressor, and probably some of its targets are oncogenes, he says. Tumor suppressor genes are normal genes that protect against the development of cancer. Oncogenes, on the other hand, promote excessive cell growth, the hallmark of cancer.

"If the miR is expressed at a high level, however, the RNA level of the targets would be low and the expression of the oncogene would be low," he says. Conversely, "knocking out" the miR gene would mean the expression of the oncogene would be high.

"MiRNAs are a new mechanism involved in malignant transformation," he says. "I think it will be found to be a very generalized mechanism and provide a lot of opportunities for treatment.

"The chip is an easy way to test for miRNA alterations," he says. "When you look at a cancer, the chip will tell you which miRNAs are in fact there and which are not. Then you can study the targets and figure out their role in cancer.

"The next step is to continue to find out how these genes are regulated and what they regulate their targets and their roles in cancers."

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Contact: Steve Benowitz
steven.benowitz@jefferson.edu
215-955-5291
Thomas Jefferson University
22-Jun-2004