Phytocannabinoids exert anti-cancer potential in preclinical in vitro models of breast cancer

Abstract

There are a multitude of challenges that are faced in the treatment of breast cancer, such as resistance to chemotherapeutic agents and chemotherapy-induced adverse side effects. Cannabis sativa is used in cancer patients under palliative care and in patients who are actively receiving chemotherapy where it functions to provide analgesic effects and mitigate some of the adverse effects induced by chemotherapy. With the use of cannabis in cancer patients comes an important question: how does cannabis or its components affect cancer or its treatment? Phytocannabinoids produced by the cannabis plant, particularly Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), have been shown to exert desirable anti-cancer effects in several cancers, including breast cancer. Some of these anti-cancer effects include reducing cancer cell proliferation, inducing apoptosis and limiting metastasis. Cannabinoids other than THC and CBD are produced by the cannabis plant and have been far less studied for their potential anti-cancer properties. The objective of this study was to explore the anti-cancer effects of multiple cannabinoids in preclinical models of breast cancer. Our study revealed that cannabinoids were cytotoxic, induced apoptosis, and reduced the invasion of breast cancer cells. Cannabinoid combinations as well as cannabinoids with doxorubicin produced additive or synergistic reductions in cell viability of breast cancer cells, including a resistant model. This study provides insight that cannabinoids and combination treatments involving cannabinoids may have therapeutic benefits as novel anti-cancer agents in the treatment of breast cancer.