While exploring why pregnant women are particularly susceptible to malaria, the researchers found that the mosquito-borne parasite produces a protein that binds to a particular type of sugar molecule in the placenta. That same sugar molecule is also found in most cancers. This commonality is understandable, because both cancers and placentas grow rapidly, often pushing aside other tissues in the process.
The researchers realized that the sugar molecule could be a target for anti-cancer drugs, and that the malarial protein, called VAR2CSA, could provide the tool for carrying such drugs to tumours. They attached a novel toxin to VAR2CSA and treated hundreds of normal and cancer cell lines. The drug compound specifically targeted and killed more than 95 per cent of the cancer cell lines.
The drug was then tested on mice that were implanted with three types of human tumours. With non-Hodgkin’s lymphoma, the treated mice’s tumours were about a quarter the size of the tumours in the control group. With prostate cancer, the tumours completely disappeared in two of the six treated mice a month after receiving the first dose. With metastatic breast cancer, five out of six treated mice were cured from metastatic disease. The mice showed no adverse side-effects, and their organs were unharmed by the therapy.
“This is an extraordinary finding that paves the way for targeting sugar molecules in pediatric and adulthood human cancer, and our groups are vigorously pursuing this possibility together,” says Sorensen, who is distinguished scientist at the BC Cancer Agency and co-senior investigator for the study.
The results were published in Cancer Cell
and two companies, Vancouver-based Kairos Therapeutics and Copenhagen-based VAR2 Pharmaceuticals, are now developing the compound for clinical trials in humans, which will take another three to four years.