Unveiling the mechanism of action behind the anti-cancer properties of cannabinoids in ER+ breast cancer cells: Impact on aromatase and steroid receptors

DNA damage and cell death in human oral squamous cell carcinoma cells: The potential biological effects of cannabidiol

OBJECTIVE

The present study examined the in vitro effects on oral squamous cell carcinoma cells (HSC-3) of cannabidiol (CBD), the main chemical component of Cannabis, proposed as a novel adjuvant therapy in the treatment of cancers.

DESIGN

Cell viability (MTT assay), morphology (SEM), apoptosis and cell cycle (flow cytometry), and DNA damage (phospho-γ-H2AX immunofluorescence) were evaluated. Cytotoxicity was evaluated with concentrations between 100 µM and 1 µM, and two concentrations were selected for subsequent analysis: 25 µM, as toxic dose, and 6.25 µM, as non-toxic.

RESULTS

CBD caused a dose- and time-dependent reduction in viability of 64 %, 96 %, and 99 % with 25 µM, 50 µM and 100 µM, respectively, after 72 h (p < 0.001), cell cycle arrest in G0-G1 phase with increased apoptosis in particular at 72 h for 25 µM (p < 0.001), significant morphological alterations with 25 µM, still present even at 6.25 µM, and significantly increased cell damage considering a significant increase in the percentage of highly positive cells (5 phosphorylated γH2AX foci), which is around 29 % for 25 µM and 19 % for 6.25 µM after 24 h.

CONCLUSIONS

CBD inhibits oral cancer growth causing DNA damage. In general, induced cell cytotoxicity appears to be dose- and time-related. Doses of CBD ≥25 μM showed a high reduction in viability. CBD could possibly represent a new therapeutic molecule for its cytotoxic effects against oral squamous cell carcinoma. The mechanism involved in the suppressive effect caused by CBD needs further investigation.

The anti-aromatase and anti-estrogenic activity of plant products in the treatment of estrogen receptor-positive breast cancer

Despite being the focal point of decades of research, female breast cancer (BC) continues to be one of the most lethal cancers in the world. Given that 80 % of all diagnosed BC cases are estrogen receptor-positive (ER+) with carcinogenesis driven by estrogen-ERα signalling, current standard of care (SOC) hormone therapies are geared towards modulating the function and expression levels of estrogen and its receptors, ERα and ERβ. Currently, aromatase inhibitors (AIs), selective ER modulators (SERMs) and selective ER degraders (SERDs) are clinically prescribed for the management and treatment of ER+ BC, with the anti-aromatase activity of AIs abrogating estrogen biosynthesis, while the anti-estrogenic SERMs and SERDs antagonise and degrade the ER, respectively. The use of SOC hormone therapies is, however, significantly hampered by the onset of severe side-effects and the development of resistance. Given that numerous studies have reported on the beneficial effects of plant compounds and/or extracts and the multiple pathways through which they target ER+ breast carcinogenesis, recent research has focused on the use of dietary chemopreventive agents for BC management. When combined with SOC treatments, several of these plant components and/or extracts have demonstrated improved efficacy and/or synergistic impact. Moreover, despite a lack of in vivo investigations, plant products are generally reported to have a lower side-effect profile than SOC therapies and are therefore thought to be a safer therapeutic choice. Thus, the current review summarizes the findings from the last five years regarding the anti-aromatase and anti-estrogenic activity of plant products, as well as their synergistic anti-ER+ BC effects in combination with SOC therapies.

Molecular Targets of Minor Cannabinoids in Breast Cancer: In Silico and In Vitro Studies

BACKGROUND

Breast cancer therapy has been facing remarkable changes. Classic treatments are now combined with other therapies to improve efficacy and surpass resistance. Indeed, the emergence of resistance demands the development of novel therapeutic approaches. Due to key estrogen signaling, estrogen receptor-positive (ER+) breast cancer treatment has always been focused on aromatase inhibition and ER modulation. Lately, the effects of phytocannabinoids, mainly Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD), have been evaluated in different cancers, including breast. However, Cannabis sativa contains more than 120 phytocannabinoids less researched and understood.

METHODS

Here, we evaluated, both in silico and in vitro, the ability of 129 phytocannabinoids to modulate important molecular targets in ER+ breast cancer: aromatase, ER, and androgen receptor (AR).

RESULTS

In silico results suggested that some cannabinoids may inhibit aromatase and act as ERα antagonists. Nine selected cannabinoids showed, in vitro, potential to act either as ER antagonists with inverse agonist properties, or as ER agonists. Moreover, these cannabinoids were considered as weak aromatase inhibitors and AR antagonists with inverse agonist action.

CONCLUSIONS

Overall, we present, for the first time, a comprehensive analysis of the actions of the phytocannabinoids in targets of ER+ breast tumors, pointing out their therapeutic potential in cancer and in other diseases.

Cannabidivarin and cannabigerol induce unfolded protein response and angiogenesis dysregulation in placental trophoblast HTR-8/SVneo cells

Cannabidivarin (CBDV) and cannabigerol (CBG) are minor phytocannabinoids from Cannabis sativa, whose health benefits have been reported. However, studies about the impact of these cannabinoids on fundamental cellular processes in placentation are scarce. Placental development involves physiological endoplasmic reticulum (ER) stress, however when exacerbated it can lead to altered angiogenesis and pregnancy disorders, such as intrauterine growth restriction and preeclampsia. In this work, the effects of CBDV and CBG (1-10 µM) on placental extravillous trophoblasts were studied, using the in vitro model HTR-8/SVneo cells. Both cannabinoids induced anti-proliferative effects and reactive oxygen/nitrogen species generation, which was dependent on transient receptor potential vanilloid 1 (TRPV1) activation. Moreover, CBDV and CBG significantly upregulated, in a TRPV-1 dependent manner, the gene expression of HSPA5/Glucose-regulated protein 78 (GRP78/BiP), a critical chaperone involved in ER stress and unfolded protein response (UPR) activation. Nevertheless, the UPR pathways were differentially activated. Both cannabinoids were able to recruit the IRE branch, while only CBDV enhanced the expression of downstream effectors of the PERK pathway, namely p-eIF2α, ATF4 and CHOP. It also augmented the activity of the apoptotic initiator caspases-8 and -9, though the effector caspases-3/-7 were not activated. TRB3 expression was increased by CBDV, which may hinder apoptosis termination. Moreover, both compounds upregulated the mRNA levels of the angiogenic factors VEGFA, PGF and sFLT1, and disrupted the endothelial-like behavior of HTR-8/SVneo cells, by reducing tube formation. Thus, CBDV and CBG treatment interferes with EVTs functions and may have a negative impact in placentation and in pregnancy outcome.

Cannabidiol and its application in the treatment of oral diseases: therapeutic potentials, routes of administration and prospects

Cannabidiol (CBD), one of the most important active ingredients in cannabis, has been reported to have some pharmacological effects such as antibacterial and analgesic effects, and to have therapeutic potential in the treatment of oral diseases such as oral cancer, gingivitis and periodontal diseases. However, there is a lack of relevant systematic research and reviews. Therefore, based on the etiology and clinical symptoms of several common oral diseases, this paper focuses on the therapeutic potential of CBD in periodontal diseases, pulp diseases, oral mucosal diseases, oral cancer and temporomandibular joint diseases. The pharmacological effects of CBD and the distribution and function of its receptors in the oral cavity are also summarized. In order to provide reference for future research and further clinical application of CBD, we also summarize several possible routes of administration and corresponding characteristics. Finally, the challenges faced while applying CBD clinically and possible solutions are discussed, and we also look to the future.

Proteome-Wide Profiling Using Sample Multiplexing of a Human Cell Line Treated with Cannabidiol (CBD) and Tetrahydrocannabinol (THC)

Cannabis has been used historically for both medicinal and recreational purposes, with the most notable cannabinoids being cannabidiol (CBD) and tetrahydrocannabinol (THC). Although their therapeutic effects have been well studied and their recreational use is highly debated, the underlying mechanisms of their biological effects remain poorly defined. In this study, we use isobaric tag-based sample multiplexed proteome profiling to investigate protein abundance differences in the human neuroblastoma SH-SY5Y cell line treated with CBD and THC. We identified significantly regulated proteins by each treatment and performed a pathway classification and associated protein-protein interaction analysis. Our findings suggest that these treatments may lead to mitochondrial dysfunction and induce endoplasmic reticulum stress. These data can potentially be interrogated further to investigate the potential role of CBD and THC in various biological and disease contexts, providing a foundation for future studies.

Cannabidiol Inhibits the Proliferation and Invasiveness of Prostate Cancer Cells

Prostate cancer is the fifth leading cause of cancer death in men, responsible for over 375,000 deaths in 2020. Novel therapeutic strategies are needed to improve outcomes. Cannabinoids, chemical components of the cannabis plant, are a possible solution. Preclinical evidence demonstrates that cannabinoids can modulate several cancer hallmarks of many tumor types. However, the therapeutic potential of cannabinoids in prostate cancer has not yet been fully explored. The aim of this study was to investigate the antiproliferative and anti-invasive properties of cannabidiol (CBD) in prostate cancer cells in vitro. CBD inhibited cell viability and proliferation, accompanied by reduced expression of key cell cycle proteins, specifically cyclin D3 and cyclin-dependent kinases CDK2, CDK4, and CDK1, and inhibition of AKT phosphorylation. The effects of CBD on cell viability were not blocked by cannabinoid receptor antagonists, a transient receptor potential vanilloid 1 (TRPV1) channel blocker, or an agonist of the G-protein-coupled receptor GPR55, suggesting that CBD acts independently of these targets in prostate cancer cells. Furthermore, CBD reduced the invasiveness of highly metastatic PC-3 cells and increased protein expression of E-cadherin. The ability of CBD to inhibit prostate cancer cell proliferation and invasiveness suggests that CBD may have potential as a future chemotherapeutic agent.

In Vitro Effects of Combining Genistein with Aromatase Inhibitors: Concerns Regarding Its Consumption during Breast Cancer Treatment

INTRODUCTION

The third-generation of aromatase inhibitors (AIs)-Exemestane (Exe), Letrozole (Let), and Anastrozole (Ana)-is the main therapeutic approach applied for estrogen receptor-positive (ER+) breast cancer (BC), the most common neoplasm in women worldwide. Despite their success, the development of resistance limits their efficacy. Genistein (G), a phytoestrogen present in soybean, has promising anticancer properties in ER+ BC cells, even when combined with anticancer drugs. Thus, the potential beneficial effects of combining G with AIs were investigated in sensitive (MCF7-aro) and resistant (LTEDaro) BC cells.

METHODS

The effects on cell proliferation and expression of aromatase, ERα/ERβ, and AR receptors were evaluated.

RESULTS

Unlike the combination of G with Ana or Let, which negatively affects the Ais' therapeutic efficacy, G enhanced the anticancer properties of the steroidal AI Exe, increasing the antiproliferative effect and apoptosis relative to Exe. The hormone targets studied were not affected by this combination when compared with Exe.

CONCLUSIONS

This is the first in vitro study that highlights the potential benefit of G as an adjuvant therapy with Exe, emphasizing, however, that soy derivatives widely used in the diet or applied as auxiliary medicines may increase the risk of adverse interactions with nonsteroidal AIs used in therapy.

Cannabidiol as a Promising Adjuvant Therapy for Estrogen Receptor-Positive Breast Tumors: Unveiling Its Benefits with Aromatase Inhibitors

BACKGROUND

Estrogen receptor-positive (ER⁺) breast cancer is the most diagnosed subtype, with aromatase inhibitors (AIs) being one of the therapeutic drug types used in the clinic. However, endocrine resistance may develop after prolonged treatment, and different approaches, such as combining endocrine and targeted therapies, have been applied. Recently, we demonstrated that cannabidiol (CBD) induces anti-tumor actions in ER⁺ breast cancer cells by targeting aromatase and ERs. Considering this, we studied, in vitro, whether CBD when combined with AIs could improve their effectiveness.

METHODS

MCF-7aro cells were used and the effects on cell viability and on the modulation of specific targets were investigated.

RESULTS

CBD when combined with anastrozole (Ana) and letrozole (Let) caused no beneficial effect in comparison to the isolated AIs. In contrast, when combined with the AI exemestane (Exe), CBD potentiated its pro-cell death effects, abolished its estrogen-like effect, impaired ERα activation, and prevented its oncogenic role on the androgen receptor (AR). Moreover, this combination inhibited ERK_1/2 activation, promoting apoptosis. The study of the hormonal microenvironment suggests that this combination should not be applied in early stages of ER⁺ breast tumors.

CONCLUSIONS

Contrary to Ana and Let, this study highlights the potential benefits of combining CBD with Exe to improve breast cancer treatment and opens up the possibility of new therapeutic approaches comprising the use of cannabinoids.

Study of potential inhibition of the estrogen receptor α by cannabinoids using an in silico approach: Agonist vs antagonist mechanism

Breast cancer is the main cancer type with more than 2.2 million cases in 2020, and is the principal cause of death in women; with 685000 deaths in 2020 worldwide. The estrogen receptor is involved at least in 70% of breast cancer diagnoses, and the agonist and antagonist properties of the drug in this receptor play a pivotal role in the control of this illness. This work evaluated the agonist and antagonist mechanisms of 30 cannabinoids by employing molecular docking and dynamic simulations. Compounds with docking scores < -8 kcal/mol were analyzed by molecular dynamic simulation at 300 ns, and relevant insights are given about the protein's structural changes, centered on the helicity in alpha-helices H3, H8, H11, and H12. Cannabicitran was the cannabinoid that presented the best relative binding-free energy (-34.96 kcal/mol), and based on rational modification, we found a new natural-based compound with relative binding-free energy (-44.83 kcal/mol) better than the controls hydroxytamoxifen and acolbifen. Structure modifications that could increase biological activity are suggested.

Machine Learning-Assisted Prediction of the Biological Activity of Aromatase Inhibitors and Data Mining to Explore Similar Compounds

Designing molecules for drugs has been a hot topic for many decades. However, it is hard and expensive to find a new molecule. Thus, the cost of the final drug is also increased. Machine learning can provide the fastest way to predict the biological activity of druglike molecules. In the present work, machine learning models are trained for the prediction of the biological activity of aromatase inhibitors. Data was collected from the literature. Molecular descriptors are calculated to be used as independent features for model training. The results showed that the R ² values for linear regression, random forest regression, gradient boosting regression, and bagging regression are 0.58, 0.84, 0.77, and 0.80, respectively. Using these models, it is possible to predict the activity of new molecules in a short period of time and at a reasonable cost. Furthermore, Tanimoto similarity is used for similarity analysis, as well as a chemical database is mined to search for similar molecules. Nonetheless, this study provides a framework for repurposing other effective drug molecules to prevent cancer.

Tetrahydrocannabinol and cannabidiol medicines for chronic pain and mental health conditions

Combination tetrahydrocannabinol (THC)/cannabidiol (CBD) medicines or CBD-only medicines are prospective treatments for chronic pain, stress, anxiety, depression, and insomnia. THC and CBD increase signaling from cannabinoid receptors, which reduces synaptic transmission in parts of the central and peripheral nervous systems and reduces the secretion of inflammatory factors from immune and glial cells. The overall effect of adding CBD to THC medicines is to enhance the analgesic effect but counteract some of the adverse effects. There is substantial evidence for the effectiveness of THC/CBD combination medicines for chronic pain, especially neuropathic and nociplastic pain or pain with an inflammatory component. For CBD-only medication, there is substantial evidence for stress, moderate evidence for anxiety and insomnia, and minimal evidence for depression and pain. THC/CBD combination medicines have a good tolerability and safety profile relative to opioid analgesics and have negligible dependence and abuse potential; however, should be avoided in patients predisposed to depression, psychosis and suicide as these conditions appear to be exacerbated. Non-serious adverse events are usually dose-proportional, subject to tachyphylaxis and are rarely dose limiting when patients are commenced on a low dose with gradual up-titration. THC and CBD inhibit several Phase I and II metabolism enzymes, which increases the exposure to a wide range of drugs and appropriate care needs to be taken. Low-dose CBD that appears effective for chronic pain and mental health has good tolerability and safety, with few adverse effects and is appropriate as an initial treatment.

Mechanisms of Cannabidiol (CBD) in Cancer Treatment: A Review

Simple Summary

Emerging evidence suggests positive outcomes from the use of CBD as a cancer treatment. CBD can relieve cancer pain and ease the side effects of chemotherapy; however, there is less research about the mechanism of CBD’s anticancer effects. In this article, recent studies on the efficacy and mechanisms of CBD’s anticancer effects in cell- and animal-based models and human clinical studies are reviewed.

Abstract

Cannabis sativa L. (Cannabis) and its bioactive compounds, including cannabinoids and non-cannabinoids, have been extensively studied for their biological effects in recent decades. Cannabidiol (CBD), a major non-intoxicating cannabinoid in Cannabis, has emerged as a promising intervention for cancer research. The purpose of this review is to provide insights into the relationship between CBD and cancer based on recent research findings. The anticancer effects of CBD are mainly mediated via its interaction with the endocannabinoid system, resulting in the alleviation of pain and the promotion of immune regulation. Published reviews have focused on the applications of CBD in cancer pain management and the possible toxicological effects of its excessive consumption. In this review, we aim to summarize the mechanisms of action underlying the anticancer activities of CBD against several common cancers. Studies on the efficacy and mechanisms of CBD on cancer prevention and intervention in experimental models (i.e., cell culture- and animal-based assays) and human clinical studies are included in this review.

Cannabinoids in Breast Cancer: Differential Susceptibility According to Subtype

Although cannabinoids have been used for centuries for diverse pathological conditions, recently, their clinical interest and application have emerged due to their diverse pharmacological properties. Indeed, it is well established that cannabinoids exert important actions on multiple sclerosis, epilepsy and pain relief. Regarding cancer, cannabinoids were first introduced to manage chemotherapy-related side effects, though several studies demonstrated that they could modulate the proliferation and death of different cancer cells, as well as angiogenesis, making them attractive agents for cancer treatment. In relation to breast cancer, it has been suggested that estrogen receptor-negative (ER-) cells are more sensitive to cannabinoids than estrogen receptor-positive (ER+) cells. In fact, most of the studies regarding their effects on breast tumors have been conducted on triple-negative breast cancer (TNBC). Nonetheless, the number of studies on human epidermal growth factor receptor 2-positive (HER2+) and ER+ breast tumors has been rising in recent years. However, besides the optimistic results obtained thus far, there is still a long way to go to fully understand the role of these molecules. This review intends to help clarify the clinical potential of cannabinoids for each breast cancer subtype.

Cannabidiol disrupts apoptosis, autophagy and invasion processes of placental trophoblasts

Cannabidiol (CBD) is a constituent of Cannabis sativa without psychotropic activity, whose medical benefits have been recognised. However, little is known about the potential toxic effects of CBD on reproductive health. Placental development involves tightly controlled processes of cell proliferation, differentiation, apoptosis, autophagy and migration/invasion of trophoblast cells. Cannabis use by pregnant women has been increasing, mainly for the relief of nausea associated with the first trimester, which raises great concern. Regarding the crucial role of cytotrophoblast cells (CTs) and extravillous trophoblasts (EVTs) in placentation, the effects of CBD (1-10 µM) were studied, using in vitro model systems BeWo and HTR-8/SVneo cell lines, respectively. CBD causes cell viability loss in a dose-dependent manner, disrupts cell cycle progression and induces apoptosis through the mitochondrial pathway, on both cell models. Moreover, CBD induces autophagy only in HTR-8/SVneo cells, being this process a promoter of apoptosis. Hypoxia-responsive genes HIF1A and SPP1 were also increased in CBD-treated HTR-8/SVneo cells suggesting a role for HIF-1α in the apoptotic and autophagic processes. In addition, CBD was able to decrease HTR-8/SVneo cell migration. Therefore, CBD interferes with trophoblast turnover and placental remodelling, which can have a considerable impact on pregnancy outcome. Thus, from an in vitro perspective our study adds new evidence for the potential negative impact of cannabis use by pregnant women.

The anti-cancer potential of crotoxin in estrogen receptor-positive breast cancer: Its effects and mechanism of action

Estrogen receptor-positive (ER⁺) breast cancer is the most diagnosed subtype of breast cancer. Currently, aromatase inhibitors (AIs) are used as first-line treatment option in this type of tumors, however they cause several side effects, which is why new therapeutic approaches are demanding. The South American rattlesnake Crotalus durissus terrificus produces a venom enriched in several bioactive substances, like phospholipases A₂ (PLA₂). One of those is crotoxin, a β-neurotoxin, that has already been reported for its anti-cancer properties in different cancers. Recently, its clinical interest has emerged and, in fact, a clinical trial in patients with advanced cancer is underway. Considering this, in this work, we studied the biological mechanisms behind the anti-cancer effects of crotoxin B (CTX) in an ER⁺ aromatase-overexpressing breast cancer cell line (MCF-7aro cells). Results revealed that CTX impairs MCF-7aro cells growth, through a cell cycle arrest at G₂/M phase, inhibition of ERK1/2 pathway and by apoptosis through activation of caspase-8. In addition, it can be considered a safe natural compound as did not affect non-cancerous cells and only showed anti-growth effects in breast cancer cells. Therefore, this study represents an important landmark to better understand the effects and mechanisms of action of crotoxin in ER⁺ breast cancer.