Breakthrough molecule prevents breast cancer recurrence and metastasis

Globally, cancer is expected to increase to 22 million cases and 13 million deaths in 2030. 

Among the many types of cancer, breast cancer comprises about 30 percent of all new cancer cases in women.

Triple-negative breast cancer (TNBC) accounts for about 10-15 percent of all breast cancers. TNBC differs from other types of invasive breast cancer in that it tends to grow and spread faster, has fewer treatment options, and tends to have a worse prognosis (outcome).

“Triple-negative breast cancer is a type of breast cancer that is usually more aggressive, harder to treat, and more likely to come back (recur) than cancers that are hormone receptor-positive or HER2-positive,” the breastcancer.org website explains.

“This means the cancer cells don’t have receptors for the hormones oestrogen or progesterone and don’t make too much of the HER2 protein. So triple-negative breast cancers don't respond to hormonal therapy medicines or the medicines that target the HER2 protein.”

According to a news release, TNBC affects 1,000 patients per year in Belgium, while the figure worldwide is 225,000.

About half of triple-negative breast cancer patients will develop local recurrences and metastases, and there is no preventative medication or treatment available. The news release puts the cure rate of TNBC at ten percent.

In 2014, a researcher at the Universite Catholique de Louvain Institute for experimental and clinical research, Pierre Sonveaux, was able to show that it was possible to stop the appearance of melanoma tumour metastases in mice. Yet the experimental molecules were only tested on animals and were not developed to be drugs for human consumption.

In the time that passed since then, Sonveaux and his team, including post-doctoral researcher Tania Capeloa, have continued their work on the subject. Now they have published a study on it.

The team has managed to demonstrate a drug that was developed for other diseases, MitoQ, “avoids the appearance of metastases in 80 percent and local recurrences of human breast cancer in 75 percent of mice.”

Mice that were not treated with MitoQ ended up seeing a recurrence of their cancer, which spread.

The experiment used mice affected by human breast cancer. The researchers treated them as a hospital would treat a breast cancer patient, that is, surgery to remove the tumour followed up by a carefully dosed cocktail of standard chemotherapies.

Yet there was a difference: this time, the scientists added MitoQ molecule to the standard treatment. The researchers were able to determine that MitoQ was compatible with standard chemotherapies, as well as the treatment with MitoQ being able to avoid metastases and local recurrences of human breast cancer in mice.

“We expected to be able to block the metastases,'' says Pierre Sonveaux. “But preventing the recurrence of the cancer was totally unexpected. Getting this type of result is a huge motivation for us to carry on.”

Considering that the three main causes of cancer deaths are recurrences, the spread of cancer by metastasis and resistance to treatment, the MitoQ treatment is promising to say the least. There is currently no other known molecule able to perform like MitoQ.

The MitoQ website notes that human mitochondria “have impermeable walls which common antioxidant supplements (such as CoQ10 and ubiquinol) cannot effectively penetrate.” Whereas MitoQ is “a very small and positively-charged advanced antioxidant which is electrochemically attracted into the mitochondria.”

The news release explains the two types of cancerous cells as those that multiply and are vulnerable to clinical treatments and those that are dormant and that “bide their time.” The latter, the release notes, is more harmful, because these cancerous stem cells are resistant to clinical treatments. It is the latter that causes cancer to metastasise, and if not removed wholly by cancer surgery, may result in recurrences.

Cancerous relapses are currently treated by chemotherapy, but because tumorous cells are resistant to treatment, the chemotherapy is mainly ineffective. However, according to the study conducted by the researchers, MitoQ molecule prevents cancerous stem cells from awakening, leaving them dormant.

Currently, the first clinical phase has been completed for MitoQ, during which it was tested on healthy subjects, men and women, and was found to be only slightly toxic (some subjects reported feeling nauseated and vomiting).

During the clinical second phase, the MitoQ molecule will be tested on cancer patients to establish its efficacy as an additional treatment for cancer.