Metastasis is the final and lethal stage of cancer, but studies have shown that it can be stopped byTHC and CBD .
Metastasis is the process by which cancer cells move from the main part of the tumor and invade nearby tissues and organs and/or move to other parts of the body. Some types of cancers are more aggressive than others, and are therefore more likely to metastasize. These cancers are very difficult to treat and are often fatal for patients. For tumor cells to migrate and invade other tissues, they must first exit the main tumor and move into the extracellular matrix (ECM) surrounding the tumor. They can then continue to grow into surrounding tissues, or they can enter the bloodstream or lymphatic system and then spread to other parts of the body.
Cell splicing, ECM degradation, and chemotaxis (or other types of cell movements) are essential processes for tumor cells to successfully metastasize. Angiogenesis is another important process in being able to support the growth of a new or existing tumor. Some studies have found that these metastatic processes can be inhibited by phytocannabinoids isolated from the Cannabis plant (THC and CBD), as well as endocannabinoids produced by our bodies and synthetic cannabinoids.
In several studies it was observed that cannabinoids stopped angiogenesis , reducing the expression of the ligand and its associated receptors in the vascular endothelial growth factor (VEGF) pathway. With the VEGF system out of whack, tumors will not be able to grow new blood vessels to help fuel its out-of-control growth. New tumors arising from metastasis of peripheral tissues, such as the lungs, also require angiogenesis to support their development and growth.
CBD has been found to inhibit the production of metalloproteinases (MMPs). These proteins play a key role in angiogenesis by separating the components of the ECM, so as to allow the formation of new blood vessels. They also help in the migration of tumor cells away from the main tumor. For a cancer cell to exit the tumor, it must use MMPs to break down the ECM surrounding the tumor. This has been proven to be especially critical for treating gliomas, which grow and spread so quickly that they are nearly impossible to remove surgically. CBD was able to reduce the aggressiveness of gliomas by inhibiting their ability to invade, in part by inhibiting MMPs.
In addition to MMPs, cell invasiveness is also governed by cell junction. Some types of adhesion molecules, such as focal adhesion kinase (FAK), promote metastasis as they increase in number. These proteins allow the cell to migrate away from the tumor more easily. Cannabinoids have been found to inhibit FAK in cancer cells , reducing their ability to migrate.
In breast cancer , CBD turned off the Id-1 gene, a metastatic gene that is a marker of aggressiveness in breast cancer. As a result, the breast cancer cells treated with CBD were less invasive. Inhibiting Id-1 produces a ripple effect, whereby other genes that promote metastasis also decrease activity, causing an overall reduction in the aggressiveness of the cancer.
Tumor metastasis is the final stage of disease progression, and usually the most fatal for cancer patients. Some laboratory studies have found that cannabinoids such as THC and CBD are effective in blocking essential processes that allow cancer cells to metastasize. Alone, or together with traditional therapies, cannabinoids could constitute a new frontier in cancer treatments.