Cannabidiol Combination Enhances Photodynamic Therapy Effects on MCF-7 Breast Cancer Cells

Cannabis sativa is a well-known plant for its psychoactive effects; however, its many derivatives, such as Cannabidiol (CBD), contain several therapeutic applications. Tetrahydrocannabinol (THC) is the main cannabis derivative responsible for psychoactive properties, while CBD is non-psychotropic. For this reason, CBD has been more exploited in the last decade. CBD has been connected to multiple anticancer properties, and when combined with photodynamic therapy (PDT), it is possible to eradicate tumors more effectively. In this study, CBD was utilized to treat MCF-7 breast cancer cells, followed by in vitro PDT combination therapy. Conventional breast cancer treatment modalities such as chemotherapy, radiotherapy, etc. have been reported for inducing a number of undesirable side effects, recurrence of the disease, and low quality of life. In this study, cells were exposed to varying concentrations of CBD (i.e., 1.25, 2.5, 5, 10, and 20 μg/mL) and incubated 12 and 24 h after treatment. The optimal doses were then used in combination therapy. Morphology and biochemical assays, including lactate dehydrogenase (LDH) for membrane integrity, adenosine triphosphate (ATP) for viability, and trypan blue exclusion assay for viability, were used to examine cellular responses after treatments. The optimal concentration was then utilized in Hypericin-Gold nanoparticles mediated PDT combination. The results revealed that, in a dose-dependent manner, conventional morphological characteristics of cell death, such as vacuolization, blebbing, and floating were observed in treated cells. The biochemical responses demonstrated an increase in LDH, a decrease in ATP, and a reduction in viability. This study demonstrated that CBD induces cell death in MCF-7 breast cancer cells cultured in vitro. The immunofluorescence results of combination therapy indicated that cell death occurred via apoptosis. In conclusion, this study proposes that the CBD and PDT combination therapy is effective in killing MCF-7 breast cancer cells in vitro by induction of apoptosis.