Scientists have created an experimental drug, derived from a poisonous weed, that can travel harmlessly through the bloodstream until it detects cancer cells and kills them, according to a press release published on Futurity.org.
The drug, G202, shrunk human prostate tumors grown in mice by an average of 50 percent within 30 days – far outperforming docetaxel, a chemotherapy drug currently used against prostate cancer – and was also highly effective against animal models of human breast, kidney and bladder cancers.
The study by scientists from Johns Hopkins University and Denmark was published in the journal Science Translational Medicine.
G202 is derived from Thapsia garganica, a weed that grows in the Mediterranean region that makes a product called thapsigargin, which has been known to be toxic to animals since the time of ancient Greece.
Scientists re-engineered the plant by chemically modifying thapsigargin so that it can travel through the bloodstream without harming healthy blood vessels and tissues. But when G202 encounters cancer tumors, a protein released by the tumors triggers the drug to release cell-killing agents into the tumor and the blood vessels that feed it (as well as other cells nearby).
“The exciting thing is that the cancer itself is activating its own demise,” senior study author John Isaacs of Johns Hopkins said in a press release.
G202 also blocks the function of another protein – known as the SERCA pump – that all cells need to stay alive. Rea searchers said that the blockage of the SERCA pump will make it difficult for tumor cells to become resistant to the drug.
Johns Hopkins physicians have performed phase I clinical trials to assess the safety of the drug and have treated 29 patients with advanced cancer. They are planning a phase II trial to test the drug on patients with prostate and liver cancers.