Cannabinoid Combination Induces Cytoplasmic Vacuolation in MCF-7 Breast Cancer Cells

Abstract

This study evaluated the synergistic anti-cancer potential of cannabinoid combinations across the MDA-MB-231 and MCF-7 human breast cancer cell lines. Cannabinoids were combined and their synergistic interactions were evaluated using median effect analysis. The most promising cannabinoid combination (C6) consisted of tetrahydrocannabinol, cannabigerol (CBG), cannabinol (CBN), and cannabidiol (CBD), and displayed favorable dose reduction indices and limited cytotoxicity against the non-cancerous breast cell line, MCF-10A. C6 exerted its effects in the MCF-7 cell line by inducing cell cycle arrest in the G2 phase, followed by the induction of apoptosis. Morphological observations indicated the induction of cytoplasmic vacuolation, with further investigation suggesting that the vacuole membrane was derived from the endoplasmic reticulum. In addition, lipid accumulation, increased lysosome size, and significant increases in the endoplasmic reticulum chaperone protein glucose-regulated protein 78 (GRP78) expression were also observed. The selectivity and ability of cannabinoids to halt cancer cell proliferation via pathways resembling apoptosis, autophagy, and paraptosis shows promise for cannabinoid use in standardized breast cancer treatment.

Cannabinoids in the landscape of cancer

“…In a recent report in gastric cancer cells, CBD-induced cell cycle arrest at the G 0 – G 1 phase and retardation in this phase corresponded to a reduction in CDK2/cyclin E protein levels (Zhang et al 2019 ). Apoptotic changes are prevalent in cannabinoids mechanism of action which include morphological changes to the cells and cytoplasmic vacuolization, an increase in cleaved caspase-3 and -9 levels and activation of the mitochondrial apoptotic pathway (Zhang et al 2019 ; Schoeman et al 2020 ). Endoplasmic reticulum (ER) stress which occurs following ceramide synthesis causes downstream apoptotic changes and increases in proapoptotic proteins, such as BAD and Bax, also resulting in an increase in reactive oxygen species (ROS) signalling (Zhang et al 2019 ).…”

Synergistic Interactions of Cannabidiol with Chemotherapeutic Drugs in MCF7 Cells: Mode of Interaction and Proteomics Analysis of Mechanisms

“…From a medicinal and pharmaceutical standpoint, nonpsychoactive phytocannabinoids—such as cannabidiol (CBD)—are the most potentially beneficial components of cannabis’ chemical space [ 2 , 8 ]. CBD has displayed a wide range of pharmacological activities in several preclinical and clinical studies that enabled its potential application in inflammation, cancer, cardiovascular diseases, epilepsy, and neurodegenerative and psychiatric disorders [ 6 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. The US Food and Drug Administration (FDA) has approved Epidiolex ®® —a pure CBD formulation—for use in patients with Lennox–Gastaut syndrome or Dravet syndrome seizures [ 19 ].…”

“…CBD was found to inhibit oestrogen-receptor-positive (ER+), -negative (ER−) or -triple-negative breast cancer cells (TNBC) in a dose-dependent manner, with relatively low IC 50 values [ 6 , 34 , 35 , 36 , 37 , 38 , 39 ]. This suggests that breast cancer cells are sensitive to CBD, while non-transformed epithelial breast cells (MCF10A) are not significantly affected [ 10 , 28 , 39 , 40 ]. Interestingly, the administration of CBD in several clinical trials, as a single dose of 150–900 mg [ 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ] or 50–1000 mg/day for up to 13 weeks [ 50 , 51 , 52 , 53 ], showed overall good tolerability and safety profile, with mild side effects [ 54 ].…”

Oxidative Stress and Multi-Organel Damage Induced by Two Novel Phytocannabinoids, CBDB and CBDP, in Breast Cancer Cells

“…The latter interesting observation needs further investigations that are not included in the present study. In a recent paper similar vacuolar structures were observed in MCF-7 cells treated with a cannabinoid combination: the authors did not determine the origin of these structures but excluded a possible origin from the plasma membrane [ 31 ]. They proposed that the cytoplasmic vacuoles could be derived from the ER; they also detected an increased number of lysosomes and the dilation of both ER and mitochondria, resulting in the activation of autophagy and paraptosis pathways.…”