Danish researchers from the University of Copenhagen, Rigshospitalet and the University of British Columbia (UBC) are close to a possible breakthrough in the fight against cancer. In just a few years, this breakthrough could become a real medical treatment of the dreaded disease.
In the search for a weapon to combat malaria in pregnancy, it has emerged that, in informal terms, malaria parasite proteins can help kill cancer. The researchers behind the discovery hope to be able to test the method on humans within the next four years.
Prof. Ali Salanti, a malaria researcher at the Finsen Centre at Rigshospitalet and the Faculty of Health and Medical Sciences at the University of Copenhagen is behind the research, in collaboration with Mads Daugaard, a cancer researcher from the University of British Columbia (UBC) in Canada. The researchers have discovered that the carbohydrate to which the malaria parasite attaches itself in the placenta in a pregnant woman, matches a carbohydrate found in cancer cells.
The research took place at the Centre for Medical Parasitology (CMP), which is part of the University of Copenhagen, Rigshospitalet's Department of Infectious Diseases at the Finsen Centre as well as the National Serum Institute (SSI).
In the laboratory, researchers made the protein to which the malaria parasite attaches itself in the placenta, and then they added a toxin. This combination of malaria protein and cell toxin seeks out the cancer cells, before being absorbed by them. The toxin is then released into the cancer cells, triggering a process that kills the cells. The process has been observed in cell cultures and in mice with cancer. The discovery has recently been described in a scientific article in the prestigious scientific journal, Cancer Cell.
"For decades, scientists have been searching for similarities between how tumours and the placenta grow. The placenta is an organ that grows very rapidly over a few months from just a few cells to an organ weighing approximately a kilogramme, and it supplies the foetus with oxygen and nourishment in a relatively foreign environment. In a way, tumours do the same thing. They grow aggressively in a foreign environment," said Ali Salanti from the Centre for Medical Parasitology.
Ali Salanti and his team are currently testing a drug against malaria in humans, and it was in connection with this development process that he discovered that the carbohydrate in the placenta was also present in cancerous tumours. Ali Salanti therefore contacted his former fellow student, Mads Daugaard, who is a cancer researcher and head of the Molecular Pathology & Cell Imaging Core Facility, Vancouver Prostate Centre at UBC in Canada. The two research teams have together achieved results, which they hope can form the basis of a treatment for cancer.
"We looked more closely at how the carbohydrate functions. In the placenta, it ensures quick growth. Our experiments showed that the same applied to cancerous tumours. We mixed the malaria parasite with cancer cells, and the parasite reacted to the cells as if they were a placenta; attaching themselves to it," said Ali Salanti.
Killing cancer cells
In a collaboration between the two universities, the research teams have tested thousands of samples, from brain tumours to leukaemia cancers, and a general picture has emerged in that it seems that the malaria protein can strike in 90% of all tumour types.
"We separated the malaria protein which attaches itself to the carbohydrate, and then we added a toxin to the protein. Through trials on mice, we demonstrated that the combination of protein and toxin helps to kill cancer cells," Mads Daugaard said.
"It appears that the malaria protein attaches to the tumour without any appreciable attachment to other tissue. The mice that were given protein and toxin had a far higher survival rate than the untreated mice. We have seen that three doses can stop tumour growth and even cause it to shrink," said Thomas Mandel Clausen, a PhD student who has worked on the project for the last two years.
It seems the only drawback to the method is that pregnant women cannot receive the treatment.
"Put simply, in the same way as the toxin thinks that the tumour is a placenta, the toxin will think that the placenta is a tumour and kill it," said Ali Salanti.
In collaboration with the researchers behind the discovery, the University of Copenhagen has set up the biotech company, VAR2pharmaceuticals, which will run clinical development in the future. Ali Salanti and Mads Daugaard and their research teams are now working specifically on the possibility of human trials.
"The earliest test scenario is in four years. The biggest questions are whether it will work in humans, and whether the human body can handle the required doses without side effects. But we're very optimistic, because the protein appears to only attach to the carbohydrate, which in humans only exists in cancerous tumours and the placenta," said Ali Salanti.
Read the scientific article in Cancer Cell