Nowadays, medical cannabis is quickly gaining more interest from many people with different diseases. But does cannabis also help with breast cancer? Breast cancer is one of the most common causes of death among women. Early diagnosis and the development of new therapies have significantly improved the prognosis, but many patients have congenital or acquired resistance to current therapies. New therapeutic approaches are therefore of great importance for the treatment of the disease.
Cannabinoids could trigger antitumor reactions
Extensive researches have shown that cannabis could be helpful in breast cancer because cannabinoids, the actives substances found in cannabis plants, may trigger antitumor reactions in various cancer animal models. Most of the studies were conducted with Δ9-Tetrahydrocannabinol (THC), the main psychoactive component of the plant. However, cannabis plants still produce countless of other compounds with their own therapeutic potentials. A combined use of all the components of cannabis plant induces a synergistic reaction, the so-called “entourage effect”, which offers a greater medical effect, compared to the use of a single isolated cannabinoid.
In addition, it was observed that the use of cannabinoids together with current therapy drugs against breast cancer has provided a better antiproliferative effect in laboratory cells, in comparison with pure THC administrations. No interactions showed up by the combination of these treatments. In summary, the results suggest that standardized cannabis preparations could be used instead of pure cannabinoids for the treatment of breast cancer.
CBD in reducing chemoresistance
Cannabidiol (CBD), a non-psychoactive phytocannabinoid produced by the cannabis plants, has shown anti-oxidant, anti-inflammatory and anti-proliferative properties.
According to a recent study carried out by the Metropolitan University in London, CBD was probably capable of inhibiting the release of exosomes and microvesicles (EMV) on adenocarcinoma (a type of breast cancer) cells. EMV are lipid bilayer-enclosed structures released by cells and involved in communication through the transfer of proteins and genetic material. The release of EMV is also associated with cancer, where a high release is associated with chemoresistance and active transfer of cancer genes, among other things.
New studies show that EMV-inhibiting agents can make cancer cells more sensitive to chemotherapeutic agents and limit cancer growth. CBD significantly reduced the exosome release of cancer cells and significantly inhibited the release of microvesicles.
Moreover, evidences suggest that changes in mitochondrial function, including modulation of STAT3 (a protein that increase certain genes expression), and the prohibitin (PHB – a mitochondrial protein that modulates certain genes expression) may be associated with the inhibition of EMV release. This leads to the conclusion that CBD may be used to make cancer cells more susceptible to chemotherapy.
CBDA avoids the spread of breast cancer cells
In cannabis plants CBD firstly appears in its acid form, known with the acronym CBDA. The cannabinoid cannabidiolic acid (CBDA) is increasingly becoming the focus of many researches. Some studies have demonstrated that CBDA provides the inhibition of cycloocygenase-2 (COX-2) activities. COX-2 has been detected in 40% of invasive human breast cancers and its functions have been linked with tumoral cell migration.
In a recent study, researchers identified a possible mechanism by which CBDA abrogates the expression of COX-2 by decreasing the c-fos, one component of the activator protein-1 (AP-1) dimer complex. AP-1 is a transcriptional factor (a macroprotein) that controls COX-2 gene expression in the nucleus of the cells. This drives to the conclusion that CBDA, as an anti-migration agent, can be very useful in aggressive human breast cancer cells by diminishing the COX-2 activity.
Different studies reported the evidence that medical cannabis can support the current treatment against breast cancer, but in order to make an accurate statement as to how far it is helpful and how exactly it should be used, it is necessary to conduct further researches and studies in humans.
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 Blasco-Benito, S., et alt. (2018). Appraising the “entourage effect”: Antitumor action of a pure cannabinoid versus a botanical drug preparation in preclinical models of breast cancer. Biochemical Pharmacology. doi:10.1016/j.bcp.2018.06.025
 Kosgodage, U. S., et alt. Cannabidiol (CBD) Is a Novel Inhibitor for Exosome and Microvesicle (EMV) Release in Cancer. Frontiers in Pharmacology, 9.doi:10.3389/fphar.2018.00889
 Takeda, S., et alt. (2016). Cannabidiolic acid-mediated selective down-regulation of c-fos in highly aggressive breast cancer MDA-MB-231 cells: possible involvement of its down-regulation in the abrogation of aggressiveness. Journal of Natural Medicines, 71(1), 286–291. doi:10.1007/s11418-016-1030-0