Cancer cells depend on two things, says the Broad Institute: a hyperactive metabolism to fuel growth and anti-oxidative enzymes to protect against potentially toxic reactive oxygen species. In a press release, the Broad announced that its researchers teamed up with colleagues at Massachusetts General Hospital and discovered a compound, called piperlongumine, that selectively blocks cancer cells' response to oxidative stress while sparing normal cells. The study, which was recently published in Nature, shows that piperlongumine is more effective than the chemotherapy drug paxlitaxel. Piperlongumine is derived from the fruit of a pepper plant found in southern India and Southeast Asia, the press release says. Because normal cells have very low levels of reactive oxygen species — and therefore low levels of the anti-oxidative enzymes — the compound doesn't target normal cells. The researchers tested piperlongumine in mice injected with human bladder, breast, lung, or melanoma cancer cells, and while it showed no toxicity in normal mice, it did inhibit tumor growth in the mice with cancer, the Broad says. "In a tougher test of mice that developed breast cancer spontaneously, piperlongumine blocked both tumor growth and metastasis," the press release adds. "In contrast, the chemotherapy drug paclitaxel (Taxol) was less effective, even at high levels." The authors say that much more work needs to be done to understand how the reactive oxygen species process works in normal and cancer cells before clinical studies on piperlongumine can be launched. They intend to learn which cancer genotypes will be most sensitive to the compound in order to predict which patients would most benefit from its use, the Broad says.
Jul 14, 2011