Dr. Janusz Rak and colleagues, Dr. Khalid Al-Nedawi and Brian Meehan, discovered that cancer cells communicate with their healthier counterparts by releasing vesicles. These bubble-like structures – called oncosomes – contain cancer-causing (oncogenic) proteins that can merge into healthy cells and “contaminate” them.
According to Dr. Rak, these oncosomes are propagating material from the interior of the cancer cell to the exterior, or into the cancer cell’s neighbourhood. “This has enabled us to see cancer as not a uni-cell process where everything is confined to the cancer cell,” he says, “but to where neighbouring cells are contaminated -- not 100 percent -- but transiently.”
Dr. Rak and his colleagues are now focusing on whether they can derive diagnostic or therapeutic therapies from these findings. Recently, one drug that binds to the oncosomes and prevents them from integrating into a target cell was tested. “When we tested this drug for anti-cancer activity in mice it turned out to be quite active as a single anticancer agent,” says Dr. Rak. “It isn’t curative, but it’s active.”
The presence of oncosomes in the blood of cancer patients could also become a clinical marker, where doctors could screen for the tumour's molecular characteristics instead of performing invasive surgery or biopsy. In the case of brain cancer, for instance, this precise assessment can’t be performed without opening a patient's skull and removing the tumour. An analysis of oncosomes would only require obtaining a small sample of blood or cerebrospinal fluid for a more comprehensive picture of that particular tumour’s molecular machinery. This could translate into more finite use of existing drugs.
“There are so many amazing drugs that are like smart bombs,” adds Dr. Rak. “They target molecules in cancer tumours, but we don’t how to use them very well yet. Hopefully by analyzing these ‘bubbles’ we will have a better idea of how to apply the ‘smart bombs,’ combine them, and optimize them for application.” The focus of this research may allow for just that.
Readers of Québec Sciencemagazine selected Dr. Janusz Rak and his team’s research as “Discovery of the Year 2008.”
