Protein Found to Block Pancreatic Tumor Growth

Researchers have found that when the human protein PNC-28 is administered to pancreatic tumor cells in animals, the tumors are destroyed.

Matthew R. Pincus, M.D., Ph.D., professor of pathology at the State University of New York (SUNY) Downstate Medical Center (Brooklyn NY, USA) and chairman of pathology and laboratory medicine at the Brooklyn Veterans Administration (VA) Hospital (NY, USA) said, "The results are very encouraging. PNC-28 may be an effective agent in treating cancers, especially if delivered directly to the tumor.”

PNC-28 is a p53 peptide, a naturally occurring human protein known to inhibit tumor growth. The researchers earlier discovered that PNC-28 triggers death of a range of human tumor cell lines, including a pancreatic cancer cell line, while not harming healthy cells.

The investigators have now given PNC-28 to laboratory animals to assess its ability to block the growth of pancreatic cancer cells. When administered over a two-week period in the peritoneal cavities of mice containing simultaneously transplanted tumors, PNC-28 caused complete destruction of these tumors. When delivered concurrently with tumor implantation, PNC-28 completely blocked tumor growth during the two-week period of administration and two weeks post-treatment, followed by weak tumor growth that leveled off at low tumor sizes.

Furthermore, according to Josef Michl, M.D., associate professor of pathology at SUNY Downstate, "When administered from a site distant from the tumor, PNC-28 still caused a decrease in tumor size. This tumor growth was significantly slower than growth in the presence of a control peptide.”

Dr. Pincus also reported that this peptide and its parent peptide, called PNC-27, are deadly to a wide variety of human cancer cells, in addition to pancreatic cancer, including colon, breast, cervical, and bone (osteogenic sarcoma) cancers. These peptides destroy cancer cells that do not even contain native p53 protein and therefore appear to have a wide applicability in treating a variety of human cancers.

The research was published in the October 1, 2006, issue of the International Journal of Cancer.



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State University of New York (SUNY) Downstate Medical Center