An innovative approach to a possible treatment for prostate and breast cancers

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Released: Sunday, March 03, 2002

Scientists at the Pennington Biomedical Research Center in collaboration with researchers at Louisiana State University have discovered an innovative approach to a possible treatment for prostate and breast cancers.

They hit upon the idea of combining part of an important reproductive hormone with a cell membrane destroying peptide. A peptide is a type of protein. They found that this combination targets prostate and breast cancer cells.

This "conjugate" binds to docking sites for a reproductive hormone-known as luteinizing hormone or LH-that is found on the membranes of breast and prostate cancer cells. The conjugate only binds to cells that have the LH docking sites.

When human prostate and breast cancer cells were grafted to laboratory mice, the treatment was "remarkably effective in destroying the tumors," with 60% to 80% of the tumors destroyed by the treatment," said Dr. William Hansel, one of the principal researchers on the project and Chief of the Pennington Center's Reproductive Biotechnology Laboratory.


Other key contributors are Drs. Carola Leuschner and Barbara Gawronska of the Pennington Center, and Dr. Fred Enright of the LSU Veterinary Science Department. Dr. Mark McLaughlin of the LSU Chemistry Department developed the membrane disrupting peptides, called PHOR 14, and Dr. Martha Juban of the LSU Protein facility produced the conjugates to LH.

Since the treatment is dependent on the number of LH receptors on the cancer cell surface, a harmless pre-treatment can be used to increase the number of receptors, thus improving the effectiveness of the treatment.

The beauty of this strategy is that the treatment produces few side effects in the treated mice. The only side effects observed were sterility, which is also a side effect of currently used chemotherapies.
The treated animals, however, maintained their body weight, and none of them suffered from the weight loss and emaciated condition observed in the untreated mice.

Treatments currently in use for prostate and breast cancers exert their effects only on fast growing tumor cells, while slow growing cancer cells respond poorly. "Our new agents target and destroy both the fast growing tumor cells and metastases," said Hansel. "We believe this approach offers considerable promise and plan to license it for testing in human patients."

"Treatments now available for breast and prostate cancer are only marginally effective," said Hansel. "Newer agents are needed to effectively kill the cancer cells. We believe this approach offers considerable promise."

Hansel said that the method has been licensed for testing in human patients. He says further studies are underway to determine the treatment's effectiveness with other cancers that contain LH receptors, such as ovarian and uterine.

The research was supported by grants from the Gordon and Mary Cain Foundation.

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The Pennington Biomedical Research Center is at the forefront of medical discovery as it relates to understanding the triggers of obesity, diabetes, cardiovascular disease, cancer and dementia. It is a campus of Louisiana State University and conducts basic, clinical and population research. The research enterprise at Pennington Biomedical includes approximately 80 faculty and more than 25 post-doctoral fellows who comprise a network of 44 laboratories supported by lab technicians, nurses, dietitians, and support personnel, and 13 highly specialized core service facilities. Pennington Biomedical's more than 500 employees perform research activities in state-of-the-art facilities on the 222-acre campus located in Baton Rouge, Louisiana.