Synthetic peptide helps defeat recurrent cancer's resistance to treatment

When certain blood cancers recur after an initial treatment, they can be highly resistant to new bouts of chemotherapy and radiation. But researchers in Boston believe they've come up with a new synthetic anti-cancer peptide that helps overcome this.

The Dana-Farber/Children's Hospital Cancer Center team developed a "stapled" BIM BH3 peptide to wield in this fight. They found in proof-of-concept studies in mice with transplanted, drug-resistant leukemia tumors that the compound on its own beat down the cancer growth. But paired with other drugs, it also showed "synergistic anti-cancer activity," according to the research team.

How did it work? Their "stapled" peptide contains what the researchers describe in their announcement as "the death-activating BH3 domain" of BIM, "an especially potent killer protein" that can bind with and cancel out all BCL-2 survival proteins. Subsequently, the special peptide appeared to neutralize the BCL-2 family survival proteins, which can kick in and help a cancer that has returned to survive a new round of treatment. But the peptide also appears to activate "pro-death" BCL-2 family proteins in cancer cells, causing them to kill themselves. BCL-2 proteins operate in the body on a regular basis, wielding both their cell killing and cell preserving functions.

Senior author Loren Walensky explains in a statement: "By using nature's solution to broad targeting of the BCL-2 pathway with a stapled BIM BH3 peptide, our goal is to eliminate cancer's protective force field and enable the arsenal of cancer treatments to do their job."

While more tests in animals and then human trials are necessary, anything that can help overcome a recurring cancer's resistance to treatment is a good thing. For more details, read the Journal of Clinical Investigation.

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