Chemo Gets Predictable

Cancer cells close to self-destruction are more receptive to chemotherapy

(RxWiki News) Chemotherapy has worked for many patients suffering from cancer, but just how it worked was uncertain. A new way to profile cancer cells has given scientists a way to predict how successful chemo can be.

Scientists at the Dana-Farber Cancer Institute have discovered that cancer cells closer to death were more susceptible to chemotherapy. Scientists then devised a test that can profile which cells are closer to death, which would let them predict how effective chemo would be in treating a malignant tumor.

"Consult your oncologist about which therapy is right for you."

This technique is called BH3 profiling. Chemo works by causing so much damage inside cancer cells that in order to not pass on this damage to future cells, the cancer cells self-destruct. This decision for a cell to self-destruct is found within mitochondria. Inside the mitochondria, the protein family called BCL-2 is divided between choosing or rejecting this decision to self-destruct.

Scientists isolated a molecule that is part of the protein family, the BH3 peptide, which is in favor of cellular destruction. By judging how much BH3 was needed to kill cells, scientists were able to determine which cells were close to death. Scientists used dye to look for holes in the mitochondria, which is one of the first signs of cellular death.

Scientists tested the BH3 profiling technique in the myeloma cells, cancerous plasma (a type of white blood cell) cells, of patients who were about to undergo chemo. They determined that the cells closest to death were more receptive to chemo. Scientists then analyzed 85 additional malignant tumors, which included ovarian cancers and two types of leukemia, and confirmed that cells closer to self-destruction were more receptive to chemotherapy.

According to the study's senior author, Anthony Letai, M.D., Ph.D., of Dana-Farber, chemotherapy was previously thought to work because it attacked fast-growing cancer cells. For Dr. Letai, this was never as accurate as it could have been and there were many exceptions to the rule. This new discovery about how chemo works can lead to better treatments for the patient and new drugs.

If oncologists can predict if chemo can be effective for a patient, that would help determine if chemo is the right choice for a patient. It could lead to an increase in the number of successful chemotherapy treatments and a decrease in the number of patients who may have unsuccessful chemo sessions despite dealing with all the possible side effects.

If cellular self-destruction affects chemo success, scientists can also develop chemotherapy drugs to be more effective. New chemotherapy drugs could be developed to help push cells to self-destruction.

For researchers, the next step is to determine if the role of cellular self-destruction and chemo receptiveness applies to other types of cancers. Additional studies could focus on whether or not this information can lead oncologists to making better decisions about which type of therapy could be used.

This study was published in the October edition of Science.  

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Review Date: 
October 30, 2011