For patients diagnosed with cancer, many turn to alternative therapies done at home in conjunction with conventional cancer treatment. Some look into whether certain off label drugs might provide cancer fighting benefits other than that for which the drug has been originally intended. Beta blocker drug propranolol is a powerful metalloproteinases 2 and 9 (MMP-2 and MMP-9) inhibitor and might be good for fighting cancer.
Beta blocker drugs are a class of medications commonly used to treat high blood pressure, irregular heartbeat (arrhythmia), and other heart problems. They are drugs that block the effects of neurotransmitters epinephrine (EPI), the body’s stress hormone adrenaline, and norepinephrine (NE) responsible for increased cardiac action.
Matrix metalloproteinases (MMPs) are calcium-dependent zinc-containing endopeptidases. These enzymes collectively are thought to play a major role in cell behavior, from cell proliferation in which the cell grows and divides to produce two daughter cells, to angiogenesis in the formation of new blood vessels, to apoptosis programed cell death, and the immune system response.
MMPs are often present in disease and development. MMPs are critical to tissue remodeling and expressed in certain cancers. MMPs are also linked to tissue damage in lung disease.
According to a review on MMP-9s and its inhibitors in cancer, it states that overexpression and dysregulation of MMP-9 is associated with various diseases. Thus, regulation and inhibition of MMP-9 is an important therapeutic approach for combating various diseases including cancer. The study says that inhibitors of MMP-9 can be used as anticancer agents although none have passed the clinical trials as an official cancer treatment.
Another study reviews beta blockers, norepinephrine, and cancer. It found there is growing evidence that neurotransmitters NE and EPI (adrenaline) affect some types of cancer. It says several studies have shown that chronic use of beta blocking drugs (which inhibit NE/EPI) results in lower recurrent, progression, or mortality of breast cancer and malignant melanoma. Psychological “fight or flight” stress response may contribute to some cases of cancer.
According to the study, NE and EPI may affect cancer by interacting with molecular pathways already implicated in abnormal cellular replication, such as the P38/MAPK pathway, or via oxidative stress. Beta blockers work by antagonizing the adrenoceptors that stress hormones activate throughout the body.
The NE/EPI-based drugs other than beta blockers could also be tested epidemiologically. They may prevent or treat various types of cancer, as may cholinesterase inhibitors (medications for memory loss) that inhibit the sympathetic nervous system.
It is important to note that the review mentions three studies that found that the chronic use of beta blockers, as well as other NE transmission decreasing drugs, is associated with an increased cancer risk and poorer survival rate. According to the study:
One interpretation of the data from these three studies is that persons who eventually take beta-blocking medications chronically for hypertension or other cardiac-related abnormalities have elevated endogenous (possibly genetic) NE signaling, predisposing them to various types of cancer and/or poorer cancer outcome.
In this scenario, beta-blocking drugs, at least in the manner in which they are currently used, may have a smaller effect on cancer risk or outcome than the underlying elevated NE signaling.18
In general, caution should be exercised in inferring from human drug studies that NE plays an etiological role in some cancers. Clinical epidemiological studies tend to be correlative and do not necessarily indicate that the factor in question, such as NE or a noradrenergic drug, is causative in a disease process.
Another point to consider is that different beta-blocking drugs, which vary in their specificity for different beta adrenoceptors, such as beta1 and beta2, may differentially affect cancer outcome in both preclinical and clinical settings.18 One beta blocker that has been used in a number of preclinical oncology studies, propranolol, blocks both beta1 and beta2 receptors.
In my personal battle with breast cancer, one of the most influential books is How to Starve Cancer… And Then Kill It with Ferroptosis by Jane McLelland. In the book, she writes how propranolol is an off-label drug that might offer anticancer benefits:
Propranolol was a beta blocker that would help reduce Vascular Endothelial Growth Factor (VEGF), the growth factor that stimulated the growth of new blood vessels to feed cancer. Propranolol also blocked matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9), so it prevented the tissue scaffold around tumor cells breaking down to allow it to metastasize, changing it from being cancer-promoting to becoming cancer-hostile.
This was enough for me to personally start taking a low dose of propranolol with the approval of my physician. I sent studies to my physician for review to start the conversation. Also, while beta blockers are not FDA approved for the treatment of anxiety-related disorders, they can produce a relaxing effect.
Please consult your physician before changing your treatment regime. If you take dipyridamole, then you should not take propranolol at the same time because both could result in a drop in blood pressure. There is the potential for adverse effects and you can read all about beta blockers here.
As we learn more about the NE/EPI genetics, we could benefit from the investigation of its effects in combination with stress and other environmental inputs, on cancer risk. If long term use of beta blockers can prevent and treat existing cases of various types of cancer, could these drugs immediately start working to reduce further progression of the disease?
Overall, these studies are encouraging because all of the above drugs have been approved for human use for many years all over the world, making it conducive for epidemiological studies. It could be a new and relatively safe category of drugs used to treat and prevent a range of cancers. At the same time, this may shed light on the processes associated with disease.