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August 18, 2006

Gene Silencer Helps Shut Down Ovarian Cancer

Topics: Ovarian Cancer

[Image - Interactions of Focal Adhesion Kinase (click image to enlarge)]

Researchers report that a new gene-based technique could help fight killer ovarian cancer:

Tiny fatty spheres (liposomes) loaded with genetic material called "short interfering RNA" (siRNA) were able to penetrate deeply into ovarian tumor cells and silence a targeted protein (FAK), say researchers at the University of Texas M.D. Anderson Cancer Center, in Houston.

FAK (focal adhesion kinase) helps ovarian cancer cells survive, so silencing the protein's expression led to a significant reduction in tumor size, the Texas team reported.

The research, conducted in mice, demonstrates the effectiveness of using liposomes to deliver siRNA directly into tumor cells. The findings were published in the journal Clinical Cancer Research.

"Short interfering RNA is a great technology we can use to silence genes, shutting down production of harmful proteins. It works well in the lab, but the question has been how to get it into tumors," study senior author Dr. Anil Sood, associate professor, departments of gynecologic oncology and cancer biology, said in a prepared statement.

While short pieces of RNA can be injected directly into a tumor, the injection methods used in the lab are not practical for treating cancer patients.

Many proteins targeted by cancer drugs are located on the surface of tumor cells. But some, like FAK, are found inside tumor cells.

"Targets like FAK, which are difficult to target with a drug, can be attacked with this liposomal siRNA approach, which penetrates deeply into the tumor," Sood said.

Mice infected with three human ovarian cancer cell lines were treated for 3 to 5 weeks. Compared to mice that received no treatment, there was a 44 percent to 72 percent reduction in mean tumor weight in mice that received the FAK-silencing liposome.

Tumor reduction was even greater (94 percent to 98 percent) in mice that received the FAK-silencing liposome plus the chemotherapy drug docetaxel.

In addition to ovarian cancer, FAK is overexpressed in colon, breast, thyroid, and head and neck cancers.

Posted by Richard at August 18, 2006 7:36 PM

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