Team of Canadian medical researchers discover cure for ovarian cancer
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We now understand the behaviour of the protein that is responsible for the formation of ovarian cancer metastases
Montreal researchers who have been working on ovarian cancer for nearly 30 years have just discovered a way to cure it. They now know how the disease cells move, which could allow them to eradicate the formation of metastases.
"The result of our research is a bit like winning the jackpot," says Dr. Anne-Marie Mes-Masson, who was met in her office at the Centre de recherche du CHUM (CRCHUM).
Ovarian cancer is the fifth leading cause of death in North America. It was diagnosed in 2800 Canadian women in 2017 and 1800 women died that same year.
At the CRCHUM, a team led by Dr. Mes-Masson and Dr. Diane Provencher discovered that a protein called Ran allowed ovarian cancer cells to move. The study was published in June in the scientific journal "Nature Communications" by their biochemist colleague Kossay Zaoui.
Ran: the metastasis taxi
It had already been determined that Ran protein plays a certain role in the expression of ovarian cancer. "Publications showed that a normal cell could do without this protein at least for a while," says Dr. Mes-Masson. However, when it was removed from tumor cells, there was a massive death of these cells."
The team concluded that ovarian cancer cells are dependent on Ran.
"Tumours were even pushed into mice, then Ran was removed and the tumours disappeared," says the scientist. Tumors only grew back when the mouse started producing Ran again."
The Montreal team discovered that in ovarian cancer, the Ran protein is used as a taxi for another protein called RhoA. RhoA is necessary for cells to move around the body and thus create metastases. "We realized that without Ran, RhoA cannot reach the membrane of an ovarian cancer cell," says Dr. Mes-Masson. It must be set to Ran."
In the case of a healthy cell, without cancer, RhoA does not need Ran to penetrate the cell. Thus, if Ran is disposed of, Rhoa loses all ability to move cancer cells. The researchers conclude that if the ability of a cell to move is inhibited, the amount of metastasis produced can be minimized.
One of the worst cancers
Ovarian cancer is also devastating because it is often diagnosed late. "Just because doctors don't do a good job," says Dr. Provencher. It's just that there's no way to detect it. I have no means of imaging or ultrasound to see what's going on before the cancer is already well underway."
It is therefore the screening that is the most difficult. "The second challenge is that we still can't cure this cancer, so a large majority of women will die from it," says Dr. Mes-Masson.
In all cases, the combination of treatments remains the best chance of survival for patients. "In 1976, we could expect a total of six months of survival. Today, half of the patients will survive five years," says Dr. Provencher.
In patients, metastases are responsible for 90% of deaths. They occur when cancer cells can move and invade healthy tissues. "Our hope is that our discovery will have an impact on other cancers," says Dr. Mes-Masson. If we can prevent metastasis, it could be an addition to the basic therapies already in use."
A tissue bank under study
Diane Provencher and Anne-Marie Mes-Masson have set up the largest biobank of ovarian cancer samples. "We've been working together on ovarian cancer for almost 30 years," says Dr. Mes-Masson. When Diane Provencher arrived in 1989, I was at the Cancer Institute, but I was working on mice. The first thing she told me was to let go of my mice and start working with humans," laughs the researcher.
Today, the two women are studying ovarian cancer behaviours on tissues collected from tumours removed from patients and from blood samples taken from these women. Since tumours can be stored as long as they are not completely exhausted, biobank samples have been available for 30 years.
"We even succeeded in making models of living cells. One time out of 100, one succeeds in creating one of these cell lines that is called immortal. We have about thirty of them now."
The tumour tissues of women with ovarian cancer, listed in the bank, have been necessary for many scientific advances here and elsewhere. "If we can share all this data, it's because women have given us
Translated with www.DeepL.com/Translator
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