Beta blockers could halt the progression of breast cancer, study finds

Scientists have long suspected that stress hormones help fuel the spread of cancer. Now, new research has uncovered how a single gene may switch this process on and off in one of the most aggressive forms of breast cancer. The discovery could lead to more precise treatments using a common class of drugs already found in medicine cabinets worldwide.

When your body responds to stress, the sympathetic nervous system releases a chemical messenger called noradrenaline. This signal doesn’t just prepare your muscles for action. In certain breast cancer cells, it binds to a receptor on the cell surface known as the beta-2 adrenoceptor. Once activated, that receptor sets off two powerful molecular signals: cyclic AMP (cAMP) and calcium.

On their own, these signals are important for many normal processes. But in cancer cells, they form a self-reinforcing loop, each amplifying the other. The result is an aggressive push for the cells to move and invade new tissue, setting the stage for metastasis.

The study zeroed in on triple-negative breast cancer (TNBC), a particularly stubborn form of the disease that lacks hormone receptors commonly targeted by existing treatments. Because it does not respond to therapies that block estrogen, progesterone, or HER2, TNBC is harder to treat and often more lethal.

Researchers tested multiple TNBC cell lines to see if the cAMP-calcium loop was active. In many cases, it was, confirming its role in driving cancer spread. But some cell lines did not sustain this feedback cycle. To figure out why, the team dug deeper into the cells’ genetic activity.

By comparing which genes were active in loop-positive versus loop-negative cells, one gene consistently stood out: HOXC12. Known for guiding developmental processes in embryos, HOXC12 had not been considered central to cancer progression. Yet here it was, emerging as the strongest marker separating cells that could maintain the invasion-promoting loop from those that could not.

The protein made by this gene, Hox-C12, delivered an even bigger surprise. Rather than staying in the nucleus to control which genes get switched on or off, Hox-C12 appeared in the cytosol, the fluid-filled space inside the cell. This suggested it was taking on a new role beyond gene regulation—possibly acting as a direct player in the signaling pathway that drives cancer spread.

To test whether HOXC12 mattered outside the lab, the researchers turned to a large database of patient genomes. Their analysis showed a clear pattern: TNBC patients with high levels of HOXC12 in their tumors had worse overall survival. This finding tied the lab observations directly to patient outcomes.

The team also used the gene-editing tool CRISPR-Cas9 to delete HOXC12 in cancer cells. Once removed, the dangerous cAMP-calcium loop shut down. Without HOXC12, the cells lost one of their main engines for invasion.

Beta blockers, a class of drugs typically prescribed for high blood pressure or heart conditions, work by blocking beta-adrenoceptors like the one triggered by noradrenaline. Past studies had hinted that TNBC patients taking beta blockers had lower mortality rates. Until now, scientists weren’t sure why.

The new work provides an explanation: if HOXC12 enables the beta-2 adrenoceptor to drive the cAMP-calcium loop, then beta blockers may stop that process cold. This means patients whose tumors have high HOXC12 could be the ones most likely to benefit from these widely available drugs.

Associate Professor Michelle Halls from the Monash Institute of Pharmaceutical Sciences, senior author of the study published in Science Signaling, said the discovery helps explain a long-standing puzzle. “There has been mounting evidence indicating a strong link between beta blockers preventing metastasis in some TNBC patients; however, until now, they didn’t know why this is the case.”

First author and PhD candidate Terrance Lam added that the patient database analysis confirmed the gene’s importance. “High levels of HOXC12 expression in patients with TNBC was associated with poorer overall survival. Taking this into account, our collective research strongly suggests that HOXC12 is a potential new indicator for when triple negative breast cancer patients could respond to beta blocker targeted interventions.”

The findings could open a pathway for doctors to test tumors for HOXC12 at diagnosis. If the gene is highly expressed, beta blockers might be prescribed alongside other therapies, giving patients a better chance at survival.

This discovery could change how oncologists treat one of the most aggressive forms of breast cancer. By using HOXC12 as a biomarker, doctors may soon be able to identify patients who could benefit from beta blocker therapy at the time of diagnosis. Since beta blockers are already widely used, safe, and affordable, the path from discovery to practical use may be faster than with entirely new drugs.

The work also highlights how developmental genes can take on unexpected roles in disease. Understanding these hidden functions could inspire new strategies not only for TNBC but also for other cancers where stress hormones drive progression.

Note: The article above provided above by The Brighter Side of News.

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