Saturday, January 10, 2009

Researchers Identify Gene that Shields Cancer from Chemotherapy

Researchers at Memorial Sloan-Kettering Cancer Center (MSKCC) have identified a gene responsible for shielding cancer cells from the effects of chemotherapy. Cancer cells, in a state of quiescence, have the ability to protect themselves. Until now, scientists have not understood which gene causes quiescence in cancer cells. If medications can be given to control the way cancer cells protect themselves from eradication, chemotherapy agents will be more effective.

The new research shows that when cancer cells do not contain P53, a protein that suppresses tumors, in addition to a gene called MEF, cancer cells become easier to kill with chemotherapy.

According to Stephen Nimer, MD, Chief of the Hematology Service and Member of the Molecular Pharmacology and Chemistry Program at MSKCC says, "This is the first time that anyone has established that p53 has a role in defining a cell's state of quiescence. Furthermore, it is surprising that some cells that lose p53 can actually be killed more readily than those that have p53 intact. "Our findings have important implications for developing therapeutic strategies that could eliminate quiescent cancer stem cells."

P53 is now known to control the MEF gene’s pathway by helping cancer cells remain dormant, promoting resistance to chemotherapy.

Dr Nimer says, “Our findings suggest that by targeting those specific genes that control quiescence in cancer cells, we may enhance the anticancer effects of chemotherapy and radiotherapy, thereby promoting their effectiveness."

The Kettering scientists also found two other genes that suppress tumors and contribute to cancer’s resistance to chemotherapy, Necdin and Gfi-1, both of which contribute to quiescence of cancer cells. When the researchers lowered the expression of Necdin and Gfi-1, in cancer cells lacking MEF, they found a significant decrease in quiescence of cancer cells.

The research is important. One of the drawbacks of cancer treatment has been resistance of cancer cells to drugs after chemotherapy is started. Scientists have been trying to find ways to ensure that chemotherapy continues to work.

The new findings provide new hope for treating cancer. By suppressing the newly discovered genes, cancer cells can be more easily destroyed by chemotherapy.

Research Shows Cell's Inactive State is Critical for Effectiveness of Cancer Treatment