Triple-negative breast cancer: Is a new treatment within reach?

Researchers are currently investigating a potential new avenue for the treatment of triple-negative breast cancer, which is a particularly aggressive breast cancer subtype.

Triple-negative breast cancer is a type of breast cancer wherein the tumors do not express estrogen receptor, progesterone receptor, or the genes that promote the production of a protein called HER2, which plays a role in the growth of some cancer cells.

These receptors typically promote the growth of cancerous tumors, and most types of breast cancer test positive for one or more of these.

By contrast, triple-negative breast cancer, as its name suggests, tests negative for these receptors. This type of cancer is especially aggressive and does not respond to the usual breast cancer therapies.

Research suggests that triple-negative breast cancer mostly affects Hispanic and African-American women, and it accounts for 10 to 20 percent of invasive breast cancer diagnoses.

A new study from the University of Freiburg in Germany is testing potential new avenues for the treatment of this type of cancer.

Dr. Jochen Maurer, from the Center for Translational Cell Research, and Dr. Roland Schüle, from the Center of Clinical Research - both based at the University of Freiburg - led groundbreaking research around cancer stem-like cells, which promote tumor growth and resilience.

Their teams developed a novel inhibitor for the epigenetic regulator KDM4, which is an enzyme that regulates gene expression and is implicated in the development of triple-negative breast cancer.

They hope that this might be the first step in devising a better, more targeted treatment for this aggressive type of cancer. The study's findings were reported in the journal Cancer Research.

In vitro tests using cancer stem cell model

Much research has been conducted in an effort to understand what scientists term "cancer stem-like cells," which are cells that are very similar to normal stem cells in the body yet which promote cancerous activity.

Cancer stem-like cells are very adaptable, and they are often able to resist to the most invasive cancer therapies, thereby leading to the formation of new tumors and metastasis.

The researchers have now managed to isolate cancer stem-like cells from human breast cancer tumors. This allowed them to have a closer look at the mechanisms of these cells and how they promote cancerous growth.

Dr. Maurer and his colleagues managed to develop an in vitro model of cancer stem-like cells that faithfully corresponded to the ones extracted from the original triple-negative breast cancer tumors.

The teams of Drs. Maurer and Schüle then collaborated in testing the effectiveness of various epigenetic inhibitors using their new cancer stem cell model.

Promising results of novel inhibitor

Drs. Maurer and Schüle found that a newly developed inhibitor of the KDM4 enzyme, called QC6352, exhibited promising effects in its action on cancer stem-like cells.

The researchers managed to stop several stem-like cell populations from proliferating, and, by using the KDM4 inhibitor, they also succeeded in determining the cells to modify their "stem" state, thus rendering them less prone to promoting cancer.

Additionally, the scientists tested the inhibitor on mice in which human breast cancer tumors had been grown. These experiments also yielded promising results, as the researchers were able to reduce the growth of the tumors in the animals.

As they told Medical News Today, "The effect of QC6352 on cancer stem cells seems to target the self-renewal of these cells. We could show that the ability to form colonies was strongly impaired in [breast cancer stem cells] treated with QC6352. Also tumors from [these cells] showed dramatically diminished growth when treated with QC6352."

"Unlike other drugs, it impedes this detrimental process of cancer stem cells to regenerate."

"Without the ability to self-renew, the cells cannot expand the tumor tissue and since their offspring, the fast-proliferating cells, are susceptible to chemotherapy a combination therapy of QC6352 and chemotherapy might eradicate both cell types, cancer stem and cancer non-stem cells," they said.

The next step from here, the team explained to us, is to adapt and develop the inhibitor so that it can be used in clinical trials. They said, "The inhibitor will be advanced and improved to generate a pharmaceutical compound ready for testing in patient phase trials, which are soon to be started."

If the scientists' further research continues to bring successful results, this will bode well for the future of triple-negative breast cancer treatment, which currently has poor long-term outcomes.