1 in 8 women will develop breast cancer during their lifetime. In fact, there are more than 3 million breast cancer survivors in the United States alone. It is one of the most common cancers, and although it poses relatively few threats to overall health, metastasis (spreading) of breast cancer into bones or the lymphatic system can be very deadly.
Many cases of breast cancer implicate hormone signalling, and hormone augmentation or reduction therapy is a common treatment plan for many cancers of reproductive origin. While breast cancer has a relatively high survival rate, CBD represents a novel treatment option that has been highly effective, especially among those with late-stage cancers.
What is cancer?
Cancer is an umbrella term that refers to an entire class of disease involving the expression of a mutated gene. Because it’s mutated, the gene doesn’t do what it’s supposed to do, so most cases of gene mutation result in an encoding failure or a product which has no effect at all. In some cases, however, a mutation does become encoded, and it causes the tissue to begin behaving abnormally. Furthermore, it causes the tissue to cease performing its biological function, and in many cases it causes the rapid proliferation that is synonymous with malignant tumors.
ID-1 gene expression in breast cancer
Many cancers are a product of chaos that disrupts many cellular components, not just the DNA. Some cancers, including most breast cancers, involve the expression of a gene, ID-1, which is only supposed to be expressed before birth. The protein encoded by this gene triggers a cascade of processes and reactions that have the net effect of explosive growth and proliferation. While an individual is a fetus, it allows the rapid development of organ systems and limb placement, but around the second trimester, it begins to disappear, for good cause. When the protein is expressed in an adult tissue sample, it causes growth at a rate much higher than normal, which contributes to the characteristic metastasis of many cancers.
Recent studies show that CBD has an extremely powerful inhibitory effect on the transcription of this gene, which produces the proteins that trigger metastasis in many cancer cell lines. The enzyme which transcribes genes involved in fetal proliferation is downregulated by CBD, so scientists know that CBD’s ability to block ID-1 production has to do with the mechanism for its transcription rather than something directly related to that specific gene, which has been the target of traditional breast cancer treatments.
ID-1 involvement in angiogenesis (the formation of new blood vessels/capillaries)
Because the ID-1 gene creates an environment highly conducive to growth and proliferation, one of the only cases in which it is correctly expressed after birth is during the formation of new blood vessels and capillaries. CBD and plant cannabinoids have been known to have an inhibitory effect on angiogenesis in general, but the specific mechanism through which they carry out this function has only been elucidated recently.
The discovery that CBD inhibits the enzyme which activates the ID-1 gene fortifies both anecdotal and clinical evidence that CBD prevents the formation of new vascular tissue and that it slows the growth of breast cancer. Furthermore, these two properties have a synergistic effect on one another because in order for a tumor to increase in diameter more than 2 mm, new capillaries are needed to feed the new tissue.
Apoptosis vs. autophagy: programmed cell death
Apoptosis and autophagy are both mechanisms by which our cells “commit suicide” when they have run their course. Apoptosis is known as programmed cell death because it is the process which almost all of our cells use to die and distribute their useful and nutritional parts to the surrounding tissue.
Autophagy comes from the latin words auto-, “self,” and phagy-, “to eat, to devour.” It refers to cases when a cell mediates its own degradation and distribution to surrounding tissue. Our cells do this naturally whenever oxidative stress or some other metabolic consequence leads to an unstable environment within an individual cell. Some kinds of apoptosis are autophagic, while others are immune cell-mediated.
Programmed cell death in breast cancer
Adult humans lose around 80,000,000,000 (billion) cells every day, and we gain about the same number in new cells. This is necessary for our health and well being, because cells can only function properly for between 5 and 10 days before they begin to malfunction. Apoptosis is the body’s way of taking the useful parts of a cell and distributing them to healthier cells that can use them more efficiently in order to promote the overall health of the organism.
Cancer cells are characterized by a peculiar aversion to apoptosis: cancer cells don’t die, they just keep reproducing. In fact, that’s what makes cancer so deadly. When normal tissue would stop increasing in size, cancerous tissues continue to proliferate, eventually metastasizing and spreading into more body systems.
CBD, especially when combined synergistically with other cannabinoids, greatly increases the rate of apoptosis that occurs in cancer cells. The exact mechanism which produces this effect is not entirely understood, but multiple independent studies have shown that cancers, especially those of digestive, immune, nervous, or reproductive origin, express inordinate amounts of cannabinoid receptors and of the mRNA for the enzymes that synthesize and degrade endocannabinoid ligands (the cannabinoids that your body produces: anandamide and 2-AG).
This sparked a paradigm shift in the understanding of how cancers work: membrane-bound CB2 receptors have the effect of inhibiting adenylate cyclase activity in their cells. This increasingly prolongs the lifespan of the cell, dependent on the quantity of receptors; cancer has orders of magnitude more receptors than healthy cells.
Adenylate cyclase can be thought of as the hose connecting a cell’s fuel tank to it’s engine: ATP (adenosine triphosphate) is a large molecule that contains a massive amount of energy; this is the cell’s fuel. Adenylate cyclase breaks this large molecule down into several smaller compounds, and in the process releases the energy that was locked in the ATP molecule so it can power your cell’s activities. One of the results of this process is the steady accumulation of cytotoxic mediators and ROS/free radicals. When these reach a critical level, (usually after about 5-10 days) programmed cell death is initiated.
By essentially cutting off the cell’s fuel line, CB2 receptor activity is ultimately correlated to the span of time that passes before a cell initiates apoptosis. In breast cancer cells that express a high number of cannabinoid receptors, this phenomenon is amplified, allowing a cancer cell to continuously delay apoptosis and continue to grow and replicate itself.
The beauty of phytocannabinoids like CBD is that many of them have a negative modulatory effect on cannabinoid receptors: they prevent the receptor from doing what it normally does in the presence of your body’s endogenous cannabinoids. When CBD blocks the CB2 receptors present in cancer cells, the cells are no longer able to delay their apoptosis. In fact, CBD produces apoptosis in cancer cells at a rate significantly greater than that of normal cells.