Rationalizing a prospective coupling effect of cannabinoids with the current pharmacotherapy for melanoma treatment

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“Melanoma is one of the leading fatal forms of cancer, yet from a treatment perspective, we have minimal control over its reoccurrence and resistance to current pharmacotherapies. The endocannabinoid system (ECS) has recently been accepted as a multifaceted homeostatic regulator, influencing various physiological processes across different biological compartments, including the skin. This review presents an overview of the pathophysiology of melanoma, current pharmacotherapy used for treatment, and the challenges associated with the different pharmacological approaches. Furthermore, it highlights the utility of cannabinoids as an additive remedy for melanoma by restoring the balance between downregulated immunomodulatory pathways and elevated inflammatory cytokines during chronic skin conditions as one of the suggested critical approaches in treating this immunogenic tumor.”

https://pubmed.ncbi.nlm.nih.gov/37920964/

“Cannabinoids, including endocannabinoids, phytocannabinoids, and synthetic agents, exert pharmacological effects on the skin by activating the specific cannabinoid receptors CB1 and CB2. Uniquely, the ECS system has been shown in vivo and in vitro to regulate the immune system through its immunomodulatory properties. They can attenuate chronic inflammatory disorders and subsequently enhance anti-tumor characteristics. In addition to their immunomodulatory effects, cannabinoids further mediate multiple anti-cancer pathways, including autophagy, apoptosis, angiogenesis, cell motility, and cell adhesion; moreover, they regulate key inflammatory processes critical to the homeostatic regulation of the tumor microenvironment. “

https://wires.onlinelibrary.wiley.com/doi/10.1002/wsbm.1633

In Vitro Antiproliferative Effect of Cannabis Extract PHEC-66 on Melanoma Cell Lines

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“Melanoma, an aggressive form of skin cancer, can be fatal if not diagnosed and treated early. Melanoma is widely recognized to resist advanced cancer treatments, including immune checkpoint inhibitors, kinase inhibitors, and chemotherapy. Numerous studies have shown that various Cannabis sativa extracts exhibit potential anticancer effects against different types of tumours both in vitro and in vivo. This study is the first to report that PHEC-66, a Cannabis sativa extract, displays antiproliferative effects against MM418-C1, MM329 and MM96L melanoma cells. Although these findings suggest that PHEC-66 has promising potential as a pharmacotherapeutic agent for melanoma treatment, further research is necessary to evaluate its safety, efficacy, and clinical applications.”

https://pubmed.ncbi.nlm.nih.gov/37887294/

“In conclusion, the results of this study demonstrate that PHEC-66 extract derived from Cannabis sativa exerts a significant cytotoxic effect on MM418-C1, MM329, and MM96L melanoma cell lines while having a lesser effect on human keratinocytes (HaCaT), human epidermal melanocytes (HEM), and normal human dermal fibroblasts (NHDF). Although the mechanism of PHEC-66’s anti-melanoma activity remains unknown, this study suggests it may induce apoptotic and necrotic cell death pathways. Further research is necessary to fully comprehend the underlying mechanisms of PHEC-66’s actions and assess its potential as a natural source of anticancer compounds.”

https://www.mdpi.com/2073-4409/12/20/2450

Differences in the phospholipid profile of melanocytes and melanoma cells irradiated with UVA and treated with cannabigerol and cannabidiol

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“UV radiation inducing mutations in melanocytes might cause melanoma. As changes in lipid composition and metabolism are associated with many types of cancer including skin cancer, we aimed to evaluate the effects of two phytocannabinoids cannabidiol (CBD) and cannabigerol (CBG), on changes in phospholipid and ceramide (CER) profiles induced by UVA irradiation in human melanocytes and melanoma. UVA radiation caused a significant up-regulation PC, PI and SM species and decrease of CERs content in both types of cells, while up-regulation of PEo was only observed in melanocytes. Exposure of UVA-irradiated melanocytes or melanoma cells to CBD and/or CBG led to significant decrease in relative content of PC, PI and SM specie; however, this effect was more pronounced in cancer cells. Interestingly, only in UVA-irradiated melanocytes and not in melanoma, PEo content was lowered after CBD treatment, while CBG led to additional up-regulation of PEo species. CBD and CBG used together caused decrease of zeta potential, inhibiting PS externalization, and different changes in relative contents of CER and SM species of irradiated and non-irradiated melanoma cells. Obtained results are quite promising due to CBD and CBG abilities to partial reverse pro-cancerogenic changes in phospholipid and CER profiles induced by UVA.”

https://pubmed.ncbi.nlm.nih.gov/37752196/

https://www.nature.com/articles/s41598-023-43363-9

Genome-Scale Metabolic Reconstruction, Non-Targeted LC-QTOF-MS Based Metabolomics Data, and Evaluation of Anticancer Activity of Cannabis sativa Leaf Extracts

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“Over the past decades, Colombia has suffered complex social problems related to illicit crops, including forced displacement, violence, and environmental damage, among other consequences for vulnerable populations. Considerable effort has been made in the regulation of illicit crops, predominantly Cannabis sativa, leading to advances such as the legalization of medical cannabis and its derivatives, the improvement of crops, and leaving an open window to the development of scientific knowledge to explore alternative uses. It is estimated that C. sativa can produce approximately 750 specialized secondary metabolites. Some of the most relevant due to their anticancer properties, besides cannabinoids, are monoterpenes, sesquiterpenoids, triterpenoids, essential oils, flavonoids, and phenolic compounds. However, despite the increase in scientific research on the subject, it is necessary to study the primary and secondary metabolism of the plant and to identify key pathways that explore its great metabolic potential. For this purpose, a genome-scale metabolic reconstruction of C. sativa is described and contextualized using LC-QTOF-MS metabolic data obtained from the leaf extract from plants grown in the region of Pesca-Boyaca, Colombia under greenhouse conditions at the Clever Leaves facility. A compartmentalized model with 2101 reactions and 1314 metabolites highlights pathways associated with fatty acid biosynthesis, steroids, and amino acids, along with the metabolism of purine, pyrimidine, glucose, starch, and sucrose. Key metabolites were identified through metabolomic data, such as neurine, cannabisativine, cannflavin A, palmitoleic acid, cannabinoids, geranylhydroquinone, and steroids. They were analyzed and integrated into the reconstruction, and their potential applications are discussed. Cytotoxicity assays revealed high anticancer activity against gastric adenocarcinoma (AGS), melanoma cells (A375), and lung carcinoma cells (A549), combined with negligible impact against healthy human skin cells.”

https://pubmed.ncbi.nlm.nih.gov/37512495/

https://www.mdpi.com/2218-1989/13/7/788

Decreased melanoma CSF-1 secretion by Cannabigerol treatment reprograms regulatory myeloid cells and reduces tumor progression

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“During solid tumor progression, the tumor microenvironment (TME) evolves into a highly immunosuppressive milieu. Key players in the immunosuppressive environment are regulatory myeloid cells, including myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs), which are recruited and activated via tumor-secreted cytokines such as colony-stimulating factor 1 (CSF-1). Therefore, the depletion of tumor-secreted cytokines is a leading anticancer strategy. Here, we found that CSF-1 secretion by melanoma cells is decreased following treatment with Cannabis extracts. Cannabigerol (CBG) was identified as the bioactive cannabinoid responsible for the effects. Conditioned media from cells treated with pure CBG or the high-CBG extract reduced the expansion and macrophage transition of the monocytic-MDSC subpopulation. Treated MO-MDSCs also expressed lower levels of iNOS, leading to restored CD8+ T-cell activation. Tumor-bearing mice treated with CBG presented reduced tumor progression, lower TAM frequencies and reduced TAM/M1 ratio. A combination of CBG and αPD-L1 was more effective in reducing tumor progression, enhancing survival and increasing the infiltration of activated cytotoxic T-cells than each treatment separately. We show a novel mechanism for CBG in modulating the TME and enhancing immune checkpoint blockade therapy, underlining its promising therapeutic potential for the treatment of a variety of tumors with elevated CSF-1 expression.”

https://pubmed.ncbi.nlm.nih.gov/37325437/

“Our findings have immediate practical implications; current treatment protocols that are already in combination with medical Cannabis as palliative care can select the CBG-rich chemovars in combination with immune checkpoint blockade therapy, making it more effective, and providing patients with antitumor properties in addition to the palliative ones.”

https://www.tandfonline.com/doi/full/10.1080/2162402X.2023.2219164

Cannabidiol and Minor Phytocannabinoids: A Preliminary Study to Assess Their Anti-Melanoma, Anti-Melanogenic, and Anti-Tyrosinase Properties

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“Currently, there is an increased interest from both scientists and consumers in the application of cannabis/hemp/phytocannabinoids in skin-related disorders. However, most previous investigations assessed the pharmacological properties of hemp extracts, cannabidiol (CBD), or tetrahydrocannabinol (THC), with very few studies focusing on minor phytocannabinoids from hemp. In this context, the current work explored the in vitro anti-melanoma, anti-melanogenic, and anti-tyrosinase effects of cannabidiol (CBD) and three minor phytocannabinoids, namely cannabigerol (CBG), cannabinol (CBN), and cannabichromene (CBC). Among the tested human malignant melanoma cells (A375, SH4, and G361), only A375 cells were highly susceptible to the 48 h treatment with the four phytocannabinoids (IC50 values between 12.02 and 25.13 μg/mL). When melanogenesis was induced in murine melanoma B16F10 cells by α-melanocyte stimulating hormone (αMSH), CBD, CBG, and CBN significantly decreased the extracellular (29.76-45.14% of αMSH+ cells) and intracellular (60.59-67.87% of αMSH+ cells) melanin content at 5 μg/mL. Lastly, CBN (50-200 μg/mL) inhibited both mushroom and murine tyrosinase, whereas CBG (50-200 μg/mL) and CBC (100-200 μg/mL) down-regulated only the mushroom tyrosinase activity; in contrast, CBD was practically inactive. The current data show that tyrosinase inhibition might not be responsible for reducing the melanin biosynthesis in α-MSH-treated B16F10 cells. By evaluating for the first time the preliminary anti-melanoma, anti-melanogenic, and anti-tyrosinase properties of CBN and CBC and confirming similar effects for CBD and CBG, this study can expand the utilization of CBD and, in particular, of minor phytocannabinoids to novel cosmeceutical products for skin care.”

https://pubmed.ncbi.nlm.nih.gov/37242431/

https://www.mdpi.com/1424-8247/16/5/648

Cannabinoids Reduce Melanoma Cell Viability and Do Not Interfere with Commonly Used Targeted Therapy in Metastatic Melanoma In Vivo and In Vitro

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“Background: Cannabinoids are mainly used for recreational purposes, but also made their way into oncology, since these substances can be taken to increase appetite in tumour cachexia. Since there are some hints in the literature that cannabinoids might have some anti-cancerous effects, the aim of this study was to study if and how cannabinoids mediate pro-apoptotic effects in metastatic melanoma in vivo and in vitro and its value besides conventional targeted therapy in vivo. 

Methods: Several melanoma cell lines were treated with different concentrations of cannabinoids, and anti-cancerous efficacy was assessed by proliferation and apoptosis assays. Subsequent pathway analysis was performed using apoptosis, proliferation, flow cytometry and confocal microscopy data. The efficacy of cannabinoids in combination with trametinib was studied in NSG mice in vivo. 

Results: Cannabinoids reduced cell viability in multiple melanoma cell lines in a dose-dependent way. The effect was mediated by CB1, TRPV1 and PPARα receptors, whereby pharmacological blockade of all three receptors protected from cannabinoid-induced apoptosis. Cannabinoids initiated apoptosis by mitochondrial cytochrome c release with consecutive activation of different caspases. Essentially, cannabinoids significantly decreased tumour growth in vivo and were as potent as the MEK inhibitor trametinib. 

Conclusions: We could demonstrate that cannabinoids reduce cell viability in several melanoma cell lines, initiate apoptosis via the intrinsic apoptotic pathway by cytochrome c release and caspase activation and do not interfere with commonly used targeted therapy.”

https://pubmed.ncbi.nlm.nih.gov/37237519/

“Cannabinoids are mainly used for recreational purposes but find their way into oncology due to ongoing legalization efforts and anti-cancerous hints in the scientific literature. The goal of this study was to elucidate the mode of action of a clinically used cannabis medication in metastatic melanoma as well as its clinical value in combination with targeted therapy. By cell viability and apoptosis assays, we could demonstrate that cannabinoids mediate their apoptotic effect in a caspase-mediated fashion by disturbing mitochondrial integrity. With in vivo experiments, we could demonstrate that clinically used cannabinoid medication does not interfere with the commonly used anti-cancerous drug trametinib. Our results suggest that cannabinoids are effective in metastatic melanoma and pave the way for further clinical trials.”

https://www.mdpi.com/2079-7737/12/5/706

Effervescent cannabidiol solid dispersion-doped dissolving microneedles for boosted melanoma therapy via the “TRPV1-NFATc1-ATF3” pathway and tumor microenvironment engineering

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“Background: Conventional dissolving microneedles (DMNs) face significant challenges in anti-melanoma therapy due to the lack of active thrust to achieve efficient transdermal drug delivery and intra-tumoral penetration.

Methods: In this study, the effervescent cannabidiol solid dispersion-doped dissolving microneedles (Ef/CBD-SD@DMNs) composed of the combined effervescent components (CaCO3 & NaHCO3) and CBD-based solid dispersion (CBD-SD) were facilely fabricated by the “one-step micro-molding” method for boosted transdermal and tumoral delivery of cannabidiol (CBD).

Results: Upon pressing into the skin, Ef/CBD-SD@DMNs rapidly produce CO2 bubbles through proton elimination, significantly enhancing the skin permeation and tumoral penetration of CBD. Once reaching the tumors, Ef/CBD-SD@DMNs can activate transient receptor potential vanilloid 1 (TRPV1) to increase Ca2+ influx and inhibit the downstream NFATc1-ATF3 signal to induce cell apoptosis. Additionally, Ef/CBD-SD@DMNs raise intra-tumoral pH environment to trigger the engineering of the tumor microenvironment (TME), including the M1 polarization of tumor-associated macrophages (TAMs) and increase of T cells infiltration. The introduction of Ca2+ can not only amplify the effervescent effect but also provide sufficient Ca2+ with CBD to potentiate the anti-melanoma efficacy. Such a “one stone, two birds” strategy combines the advantages of effervescent effects on transdermal delivery and TME regulation, creating favorable therapeutic conditions for CBD to obtain stronger inhibition of melanoma growth in vitro and in vivo.

Conclusions: This study holds promising potential in the transdermal delivery of CBD for melanoma therapy and offers a facile tool for transdermal therapies of skin tumors.”

https://pubmed.ncbi.nlm.nih.gov/37198657/

“In summary, the novel Ef/CBD-SD@DMNs system developed in this study offers a promising approach to improve the efficacy of CBD-based therapy for melanoma. Ef/CBD-SD@DMNs combines the advantages of effervescence and CBD-based solid dispersion to achieve better transdermal and tumoral delivery of CBD. The in vitro and in vivo results demonstrate that Ef/CBD-SD@DMNs can not only effectively induce melanoma apoptosis via the “Ca2+ influx-NFATc1-ATF3” pathway but also activate the tumor microenvironment probably through increasing intra-tumoral pH environment. This study provides a facile and efficient design for a transdermal delivery system that may have a significant impact on the development of new melanoma therapies.”

https://biomaterialsres.biomedcentral.com/articles/10.1186/s40824-023-00390-x

The Anti-Tumorigenic Role of Cannabinoid Receptor 2 in Non-Melanoma Skin Cancer

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“Five million non-melanoma skin cancers occur globally each year, and it is one of the most common malignant cancers. The dysregulation of the endocannabinoid system, particularly cannabinoid receptor 2 (CB2), is implicated in skin cancer development, progression, and metastasis. Comparing wildtype (WT) to systemic CB2 knockout (CB2-/-) mice, we performed a spontaneous cancer study in one-year old mice, and subsequently used the multi-stage chemical carcinogenesis model, wherein cancer is initiated by 7,12-dimethylbenz[a]anthracene (DMBA) and promoted by 12-O-tetradecanoylphorbol-13-acetate (TPA). We found that aging CB2-/- mice have an increased incidence of spontaneous cancerous and precancerous skin lesions compared to their WT counterparts. In the DMBA/TPA model, CB2-/- developed more and larger papillomas, had decreased spontaneous regression of papillomas, and displayed an altered systemic immune profile, including upregulated CD4+ T cells and dendritic cells, compared to WT mice. Immune cell infiltration in the tumor microenvironment was generally low for both genotypes, although a trend of higher myeloid-derived suppressor cells was observed in the CB2-/- mice. CB2 expression in carcinogen-exposed skin was significantly higher compared to naïve skin in WT mice, suggesting a role of CB2 on keratinocytes. Taken together, our data show that endogenous CB2 activation plays an anti-tumorigenic role in non-melanoma skin carcinogenesis, potentially via an immune-mediated response involving the alteration of T cells and myeloid cells coupled with the modulation of keratinocyte activity.”

https://pubmed.ncbi.nlm.nih.gov/37175480/

“We show that endogenous CB2 activation lowers the risk for spontaneous cancer development in aging mice and papilloma development in a chemically-induced model of skin carcinogenesis. CB2 activation can modulate the systemic immune response and reduce tumorigenesis, either by an immune-mediated response involving the alteration of T cells and myeloid cells, or by the modulation of keratinocyte proliferation. This implies that CB2 could have an anti-tumorigenic role in skin cancer and serve as a potential treatment target.”

https://www.mdpi.com/1422-0067/24/9/7773

Neuronal Cannabinoid CB1 Receptors Suppress the Growth of Melanoma Brain Metastases by Inhibiting Glutamatergic Signalling

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“Melanoma is one of the deadliest forms of cancer. Most melanoma deaths are caused by distant metastases in several organs, especially the brain, the so-called melanoma brain metastases (MBMs). However, the precise mechanisms that sustain the growth of MBMs remain elusive. Recently, the excitatory neurotransmitter glutamate has been proposed as a brain-specific, pro-tumorigenic signal for various types of cancers, but how neuronal glutamate shuttling onto metastases is regulated remains unknown. Here, we show that the cannabinoid CB1 receptor (CB1R), a master regulator of glutamate output from nerve terminals, controls MBM proliferation. First, in silico transcriptomic analysis of cancer-genome atlases indicated an aberrant expression of glutamate receptors in human metastatic melanoma samples. Second, in vitro experiments conducted on three different melanoma cell lines showed that the selective blockade of glutamatergic NMDA receptors, but not AMPA or metabotropic receptors, reduces cell proliferation. Third, in vivo grafting of melanoma cells in the brain of mice selectively devoid of CB1Rs in glutamatergic neurons increased tumour cell proliferation in concert with NMDA receptor activation, whereas melanoma cell growth in other tissue locations was not affected. Taken together, our findings demonstrate an unprecedented regulatory role of neuronal CB1Rs in the MBM tumour microenvironment.”

https://pubmed.ncbi.nlm.nih.gov/37173906/

https://www.mdpi.com/2072-6694/15/9/2439