The Endocannabinoid System as a Pharmacological Target for New Cancer Therapies

“Despite the long history of cannabinoid use for medicinal and ritual purposes, an endogenous system of cannabinoid-controlled receptors, as well as their ligands and the enzymes that synthesise and degrade them, was only discovered in the 1990s. Since then, the endocannabinoid system has attracted widespread scientific interest regarding new pharmacological targets in cancer treatment among other reasons.

Meanwhile, extensive preclinical studies have shown that cannabinoids have an inhibitory effect on tumour cell proliferation, tumour invasion, metastasis, angiogenesis, chemoresistance and epithelial-mesenchymal transition (EMT) and induce tumour cell apoptosis and autophagy as well as immune response. Appropriate cannabinoid compounds could moreover be useful for cancer patients as potential combination partners with other chemotherapeutic agents to increase their efficacy while reducing unwanted side effects.

In addition to the direct activation of cannabinoid receptors through the exogenous application of corresponding agonists, another strategy is to activate these receptors by increasing the endocannabinoid levels at the corresponding pathological hotspots. Indeed, a number of studies accordingly showed an inhibitory effect of blockers of the endocannabinoid-degrading enzymes fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) on tumour development and spread.

This review summarises the relevant preclinical studies with FAAH and MAGL inhibitors compared to studies with cannabinoids and provides an overview of the regulation of the endocannabinoid system in cancer.”

https://pubmed.ncbi.nlm.nih.gov/34830856/

“Cannabinoids have been shown to suppress tumour cell proliferation, tumour invasion, metastasis, angiogenesis, chemoresistance and epithelial-mesenchymal transition and to induce tumour cell apoptosis, autophagy and immune response. This review focuses on the current status of investigations on the impact of inhibitors of endocannabinoid-degrading enzymes on tumour growth and spread in preclinical oncology research.”

https://www.mdpi.com/2072-6694/13/22/5701


Plant-derived cannabinoids as anticancer agents

“Substantial preclinical evidence demonstrates the antiproliferative, cytotoxic, and antimetastatic properties of plant-derived cannabinoids (phytocannabinoids) such as cannabidiol and tetrahydrocannabinol. The cumulative body of research into the intracellular mechanisms and phenotypic effects of these compounds supports a logical, judicious progression to large-scale phase II/III clinical trials in certain cancer types to truly assess the efficacy of phytocannabinoids as anticancer agents.”

https://pubmed.ncbi.nlm.nih.gov/35260379/

Cannabidiol and Other Phytocannabinoids as Cancer Therapeutics

“Preclinical models provided ample evidence that cannabinoids are cytotoxic against cancer cells. Among the best studied phytocannabinoids, cannabidiol (CBD) is most promising for the treatment of cancer as it lacks the psychotomimetic properties of delta-9-tetrahydrocannabinol (THC). In vitro studies and animal experiments point to a concentration- (dose-)dependent anticancer effect. The effectiveness of pure compounds versus extracts is the subject of an ongoing debate. Actual results demonstrate that CBD-rich hemp extracts must be distinguished from THC-rich cannabis preparations. Whereas pure CBD was superior to CBD-rich extracts in most in vitro experiments, the opposite was observed for pure THC and THC-rich extracts, although exceptions were noted. The cytotoxic effects of CBD, THC and extracts seem to depend not only on the nature of cannabinoids and the presence of other phytochemicals but also largely on the nature of cell lines and test conditions. Neither CBD nor THC are universally efficacious in reducing cancer cell viability. The combination of pure cannabinoids may have advantages over single agents, although the optimal ratio seems to depend on the nature of cancer cells; the existence of a ‘one size fits all’ ratio is very unlikely. As cannabinoids interfere with the endocannabinoid system (ECS), a better understanding of the circadian rhythmicity of the ECS, particularly endocannabinoids and receptors, as well as of the rhythmicity of biological processes related to the growth of cancer cells, could enhance the efficacy of a therapy with cannabinoids by optimization of the timing of the administration, as has already been reported for some of the canonical chemotherapeutics. Theoretically, a CBD dose administered at noon could increase the peak of anandamide and therefore the effects triggered by this agent. Despite the abundance of preclinical articles published over the last 2 decades, well-designed controlled clinical trials on CBD in cancer are still missing. The number of observations in cancer patients, paired with the anticancer activity repeatedly reported in preclinical in vitro and in vivo studies warrants serious scientific exploration moving forward.”

https://pubmed.ncbi.nlm.nih.gov/35244889/

Cannabis as a potential compound against various malignancies, legal aspects, advancement by exploiting nanotechnology and clinical trials

“Various preclinical and clinical studies exhibited the potential of cannabis against various diseases, including cancer and related pain. Subsequently, many efforts have been made to establish and develop cannabis-related products and make them available as prescription products. Moreover, FDA has already approved some cannabis-related products, and more advancement in this aspect is still going on. However, the approved product of cannabis is in oral dosage form, which exerts various limitations to achieve maximum therapeutic effects. A considerable translation is on a hike to improve bioavailability, and ultimately, the therapeutic efficacy of cannabis by the employment of nanotechnology. Besides the well-known psychotropic effects of cannabis upon the use at high doses, literature has also shown the importance of cannabis and its constituents in minimising the lethality of cancer in the preclinical models. This review discusses the history of cannabis, its legal aspect, safety profile, the mechanism by which cannabis combats with cancer, and the advancement of clinical therapy by exploiting nanotechnology. A brief discussion related to the role of cannabinoid in various cancers has also been incorporated. Lastly, the information regarding completed and ongoing trials have also been elaborated.”

https://pubmed.ncbi.nlm.nih.gov/35321629/

Cannabinoids in dermatology: a scoping review.

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“The therapeutic applications of cannabis and cannabinoids are an increasingly conspicuous topic as de-criminalization and legalization of these products continues to expand.

A limited number of cannabinoid compounds have been approved for a specific set of conditions. However, the current role of cannabinoids for the treatment of dermatologic conditions remains to be defined.

We conducted a review of the current literature to determine the applications of cannabinoids for the therapy of various skin diseases.

After conducting our analysis, we found that cannabinoid products have the potential to treat a variety of skin conditions, including acne vulgaris, allergic contact dermatitis, asteatotic dermatitis, atopic dermatitis, hidradenitis suppurativa, Kaposi sarcoma, pruritus, psoriasis, skin cancer, and the cutaneous manifestations of systemic sclerosis. However, the majority of available data on these compounds are pre-clinical and there is a corresponding lack of high-quality randomized, controlled trials that evaluate their effects.

Cannabinoids have shown some initial promise as therapy for a variety of skin diseases. However, there is a requirement for thorough pre-clinical research and large-scale, randomized, controlled trials before cannabinoids can be considered safe and effective treatments for these conditions.”

“The endocannabinoid system of the skin. A potential approach for the treatment of skin disorders”  https://www.sciencedirect.com/science/article/abs/pii/S0006295218303484

ENDOCANNABINOID SYSTEM: A multi-facet therapeutic target.

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“Cannabis sativa is also popularly known as marijuana. It is being cultivated and used by man for recreational and medicinal purposes from many centuries.

Study of cannabinoids was at bay for very long time and its therapeutic value could not be adequately harnessed due to its legal status as proscribed drug in most of the countries.

The research of drugs acting on endocannabinoid system has seen many ups and down in recent past. Presently, it is known that endocannabinoids has role in pathology of many disorders and they also serve “protective role” in many medical conditions.

Several diseases like emesis, pain, inflammation, multiple sclerosis, anorexia, epilepsy, glaucoma, schizophrenia, cardiovascular disorders, cancer, obesity, metabolic syndrome related diseases, Parkinson’s disease, Huntington’s disease, Alzheimer’s disease and Tourette’s syndrome could possibly be treated by drugs modulating endocannabinoid system.

Presently, cannabinoid receptor agonists like nabilone and dronabinol are used for reducing the chemotherapy induced vomiting. Sativex (cannabidiol and THC combination) is approved in the UK, Spain and New Zealand to treat spasticity due to multiple sclerosis. In US it is under investigation for cancer pain, another drug Epidiolex (cannabidiol) is also under investigation in US for childhood seizures. Rimonabant, CB1 receptor antagonist appeared as a promising anti-obesity drug during clinical trials but it also exhibited remarkable psychiatric side effect profile. Due to which the US Food and Drug Administration did not approve Rimonabant in US. It sale was also suspended across the EU in 2008.

Recent discontinuation of clinical trial related to FAAH inhibitor due to occurrence of serious adverse events in the participating subjects could be discouraging for the research fraternity. Despite of some mishaps in clinical trials related to drugs acting on endocannabinoid system, still lot of research is being carried out to explore and establish the therapeutic targets for both cannabinoid receptor agonists and antagonists.

One challenge is to develop drugs that target only cannabinoid receptors in a particular tissue and another is to invent drugs that acts selectively on cannabinoid receptors located outside the blood brain barrier. Besides this, development of the suitable dosage forms with maximum efficacy and minimum adverse effects is also warranted.

Another angle to be introspected for therapeutic abilities of this group of drugs is non-CB1 and non-CB2 receptor targets for cannabinoids.

In order to successfully exploit the therapeutic potential of endocannabinoid system, it is imperative to further characterize the endocannabinoid system in terms of identification of the exact cellular location of cannabinoid receptors and their role as “protective” and “disease inducing substance”, time-dependent changes in the expression of cannabinoid receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27086601

Ligands for cannabinoid receptors, promising anticancer agents.

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“Cannabinoid compounds are unique to cannabis and provide some interesting biological properties.

These compounds along with endocannabinoids, a group of neuromodulator compounds in the body especially in brain, express their effects by activation of G-protein-coupled cannabinoid receptors, CB1 and CB2.

There are several physiological properties attributed to the endocannabinoids including pain relief, enhancement of appetite, blood pressure lowering during shock, embryonic development, and blocking of working memory.

On the other hand, activation of endocannabinoid system may be suppresses evolution and progression of several types of cancer.

According to the results of recent studies, CB receptors are over-expressed in cancer cell lines and application of multiple cannabinoid or cannabis-derived compounds reduce tumor size through decrease of cell proliferation or induction of cell cycle arrest and apoptosis along with desirable effect on decrease of tumor-evoked pain.

Therefore, modulation of endocannabinoid system by inhibition of fatty acid amide hydrolase (FAAH), the enzyme, which metabolized endocannabinoids, or application of multiple cannabinoid or cannabis-derived compounds, may be appropriate for the treatment of several cancer subtypes. This review focuses on how cannabinoid affect different types of cancers.”

http://www.ncbi.nlm.nih.gov/pubmed/26764235

http://www.thctotalhealthcare.com/category/cancer/

Cannabis May Help Combat Cancer-causing Herpes Viruses

ScienceDaily: Your source for the latest research news

“The compound in marijuana that produces a high, delta-9 tetrahydrocannbinol or THC, may block the spread of several forms of cancer causing herpes viruses, University of South Florida College of Medicine scientists report.

The findings, published Sept. 15 in the online journal BMC Medicine, could lead to the creation of antiviral drugs based on nonpsychoactive derivatives of THC.

The gamma herpes viruses include Kaposi’s Sarcoma Associated Herpes virus, which is associated with an increased risk of cancer that is particularly prevalent in AIDS sufferers. Another is Epstein-Barr virus, which predisposes infected individuals to cancers such as Burkitt’s lymphoma and Hodgkin’s disease.

Once a person is infected, these viruses can remain dormant for long periods within white blood cells before they burst out and begin replicating. This reactivation of the virus boosts the number of cells infected thereby increasing the chances that the cells will become cancerous.

The USF team, led by virologist Peter Medveczky, MD, found that this sudden reactivation was prevented if infected cells were grown in the presence of THC. While cells infected with a mouse gamma herpes virus normally died when the virus was reactivated, these same cells survived when cultured in the laboratory along with the cannabinoid compound – further evidence that THC prevents viral reactivation.

Furthermore, the researchers showed that THC acts specifically on gamma herpes viruses. The chemical had no effect on another related virus, herpes simplex-1, which causes cold sores and genital herpes.

Small concentrations of THC were more potent and selective against gamma herpes viruses than the commonly used antiviral drugs acyclovir, gancicyclovir and foscamet, said Dr. Medveczky, a professor in the Department of Medical Microbiology and Immunology.

The USF researchers suggest that THC selectively inhibits the spread of gamma herpes viruses by targeting a gene these viruses all share called ORF50.”

http://www.sciencedaily.com/releases/2004/09/040923092627.htm

Endocannabinoid system in cancer cachexia.

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“More than 60% of advanced cancer patients suffer from anorexia and cachexia.

This review focuses on the possible mechanisms by which the endocannabinoid system antagonizes cachexia-anorexia processes in cancer patients and how it can be tapped for therapeutic applications.

Cannabinoids stimulate appetite and food intake…

Cannabinoid type 1 receptor activation stimulates appetite and promotes lipogenesis and energy storage.

Further study of cancer-cachexia pathophysiology and the role of endocannabinoids will help us to develop cannabinoids without psychotropic properties, which will help cancer patients suffering from cachexia and improve outcomes of clinical antitumor therapy.”

http://www.ncbi.nlm.nih.gov/pubmed/17563462

The endocannabinoid signaling system in cancer.

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“The endocannabinoid system, comprising lipid-derived endocannabinoids, their G-protein-coupled receptors (GPCRs), and the enzymes for their metabolism, is emerging as a promising therapeutic target in cancer.

This report highlights the main signaling pathways for the antitumor effects of the endocannabinoid system in cancer and its basic role in cancerpathogenesis, and discusses the alternative view of cannabinoid receptors as tumor promoters.

We focus on new players in the antitumor action of the endocannabinoid system and on emerging crosstalk among cannabinoid receptors and other membrane or nuclear receptors involved in cancer.”

http://www.ncbi.nlm.nih.gov/pubmed/23602129