Antitumor Cannabinoid Chemotypes: Structural Insights.

Image result for frontiers in pharmacology“Cannabis has long been known to limit or prevent nausea and vomiting, lack of appetite, and pain. For this reason, cannabinoids have been successfully used in the treatment of some of the unwanted side effects caused by cancer chemotherapy.

Besides their palliative effects, research from the past two decades has demonstrated their promising potential as antitumor agents in a wide variety of tumors.

Cannabinoids of endogenous, phytogenic, and synthetic nature have been shown to impact the proliferation of cancer through the modulation of different proteins involved in the endocannabinoid system such as the G protein-coupled receptors CB1, CB2, and GRP55, the ionotropic receptor TRPV1, or the fatty acid amide hydrolase (FAAH).

In this article, we aim to structurally classify the antitumor cannabinoid chemotypes described so far according to their targets and types of cancer. In a drug discovery approach, their in silico pharmacokinetic profile has been evaluated in order to identify appropriate drug-like profiles, which should be taken into account for further progress toward the clinic.

This analysis may provide structural insights into the selection of specific cannabinoid scaffolds for the development of antitumor drugs for the treatment of particular types of cancer.” https://www.ncbi.nlm.nih.gov/pubmed/31214034

“The first report on the antitumor activity of phytocannabinoids was published over four decades ago. During these last years, significant research has been focused on the therapeutic potential of cannabinoids to manage palliative effects in cancer patients. Besides such palliative applications, some cannabinoids have shown anticancer properties. Since inflammation is a common risk factor for cancer, and some cannabinoids have shown anti-inflammatory properties, they could play a role in chemoprevention.” https://www.frontiersin.org/articles/10.3389/fphar.2019.00621/full
“Antitumor effects of THC.” http://www.ncbi.nlm.nih.gov/pubmed/11097557
“Antitumor effects of cannabidiol” http://www.ncbi.nlm.nih.gov/pubmed/14617682
“Anti-tumour actions of cannabinoids.” https://www.ncbi.nlm.nih.gov/pubmed/30019449
“Extensive preclinical research has demonstrated that cannabinoids, the active ingredients of Cannabis sativa, trigger antitumor responses in different models of cancer.” https://www.ncbi.nlm.nih.gov/pubmed/29940172

Should Oncologists Recommend Cannabis?

“Cannabis is a useful botanical with a wide range of therapeutic potential. Global prohibition over the past century has impeded the ability to study the plant as medicine. However, delta-9-tetrahydrocannabinol (THC) has been developed as a stand-alone pharmaceutical initially approved for the treatment of chemotherapy-related nausea and vomiting in 1986. The indication was expanded in 1992 to include treatment of anorexia in patients with the AIDS wasting syndrome. Hence, if the dominant cannabinoid is available as a schedule III prescription medication, it would seem logical that the parent botanical would likely have similar therapeutic benefits. The system of cannabinoid receptors and endogenous cannabinoids (endocannabinoids) has likely developed to help us modulate our response to noxious stimuli. Phytocannabinoids also complex with these receptors, and the analgesic effects of cannabis are perhaps the best supported by clinical evidence. Cannabis and its constituents have also been reported to be useful in assisting with sleep, mood, and anxiety. Despite significant in vitro and animal model evidence supporting the anti-cancer activity of individual cannabinoids-particularly THC and cannabidiol (CBD)-clinical evidence is absent. A single intervention that can assist with nausea, appetite, pain, mood, and sleep is certainly a valuable addition to the palliative care armamentarium. Although many healthcare providers advise against the inhalation of a botanical as a twenty-first century drug-delivery system, evidence for serious harmful effects of cannabis inhalation is scant and a variety of other methods of ingestion are currently available from dispensaries in locales where patients have access to medicinal cannabis. Oncologists and palliative care providers should recommend this botanical remedy to their patients to gain first-hand evidence of its therapeutic potential despite the paucity of results from randomized placebo-controlled clinical trials to appreciate that it is both safe and effective and really does not require a package insert.”

https://www.ncbi.nlm.nih.gov/pubmed/31161270

https://link.springer.com/article/10.1007%2Fs11864-019-0659-9

Modulation of the Endocannabinoid System as a Potential Anticancer Strategy.

 Image result for frontiers in pharmacology“Currently, the involvement of the endocannabinoid system in cancer development and possible options for a cancer-regressive effect of cannabinoids are controversially discussed. In recent decades, a number of preclinical studies have shown that cannabinoids have an anticarcinogenic potential. Therefore, especially against the background of several legal simplifications with regard to the clinical application of cannabinoid-based drugs, an extended basic knowledge about the complex network of the individual components of the endocannabinoid system is required. The canonical endocannabinoid system consists of the endocannabinoids N-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol as well as the Gi/o protein-coupled transmembrane cannabinoidreceptors CB1 and CB2. As a result of extensive studies on the broader effect of these factors, other fatty acid derivatives, transmembrane and intracellular receptors, enzymes and lipid transporters have been identified that contribute to the effect of endocannabinoids when defined in the broad sense as “extended endocannabinoid system.” Among these additional components, the endocannabinoid-degrading enzymes fatty acid amide hydrolase and monoacylglycerol lipase, lipid transport proteins of the fatty acid-binding protein family, additional cannabinoid-activated G protein-coupled receptors such as GPR55, members of the transient receptor family, and peroxisome proliferator-activated receptors were identified as targets for possible strategies to combat cancer progression. Other endocannabinoid-related fatty acids such as 2-arachidonoyl glyceryl ether, O-arachidonoylethanolamine, N-arachidonoyldopamine and oleic acid amide showed an effect via cannabinoid receptors, while other compounds such as endocannabinoid-like substances exert a permissive action on endocannabinoid effects and act via alternative intracellular target structures. This review gives an overview of the modulation of the extended endocannabinoid system using the example of anticancer cannabinoid effects, which have been described in detail in preclinical studies.”

https://www.ncbi.nlm.nih.gov/pubmed/31143113

“In addition to the palliative effects of cannabinoid compounds in cancer treatment, the endocannabinoid system provides several targets for systemic anticancer treatment. Accordingly, preclinical studies suggest cannabinoids inhibit cancer progression via inhibition of cancer cell proliferation, neovascularization, invasion and chemoresistance, as well as induction of apoptosis, autophagy and increase of tumor immune surveillance.”

https://www.frontiersin.org/articles/10.3389/fphar.2019.00430/full

Cannabidiol (CBD) Is a Novel Inhibitor for Exosome and Microvesicle (EMV) Release in Cancer.

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“Exosomes and microvesicles (EMV) are lipid bilayer-enclosed structures, released by cells and involved in intercellular communication through transfer of proteins and genetic material. EMV release is also associated with various pathologies, including cancer, where increased EMV release is amongst other associated with chemo-resistance and active transfer of pro-oncogenic factors.

Recent studies show that EMV-inhibiting agents can sensitize cancer cells to chemotherapeutic agents and reduce cancer growth in vivo.

Cannabidiol (CBD), a phytocannabinoid derived from Cannabis sativa, has anti-inflammatory and anti-oxidant properties, and displays anti-proliferative activity.

Here we report a novel role for CBD as a potent inhibitor of EMV release from three cancer cell lines: prostate cancer (PC3), hepatocellular carcinoma (HEPG2) and breast adenocarcinoma (MDA-MB-231).

CBD significantly reduced exosome release in all three cancer cell lines, and also significantly, albeit more variably, inhibited microvesicle release.

The EMV modulating effects of CBD were found to be dose dependent (1 and 5 μM) and cancer cell type specific. Moreover, we provide evidence that this may be associated with changes in mitochondrial function, including modulation of STAT3 and prohibitin expression, and that CBD can be used to sensitize cancer cells to chemotherapy.

We suggest that the known anti-cancer effects of CBD may partly be due to the regulatory effects on EMV biogenesis, and thus CBD poses as a novel and safe modulator of EMV-mediated pathological events.”

https://www.ncbi.nlm.nih.gov/pubmed/30150937

https://www.frontiersin.org/articles/10.3389/fphar.2018.00889/full

Anti-tumoural actions of cannabinoids.

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“The endocannabinoid system has emerged as a considerable target for the treatment of diverse diseases.

In addition to the well-established palliative effects of cannabinoids in cancer therapy, phytocannabinoids, synthetic cannabinoid compounds as well as inhibitors of endocannabinoid degradation have attracted attention as possible systemic anticancer drugs.

As a matter of fact, accumulating data from preclinical studies suggest cannabinoids elicit effects on different levels of cancer progression, comprising inhibition of proliferation, neovascularisation, invasion and chemoresistance, induction of apoptosis and autophagy as well as enhancement of tumour immune surveillance.

Although the clinical use of cannabinoid receptor ligands is limited by their psychoactivity, nonpsychoactive compounds, such as cannabidiol, have gained attention due to preclinically established anticancer properties and a favourable risk-to-benefit profile.

Thus, cannabinoids may complement the currently used collection of chemotherapeutics, as a broadly diversified option for cancer treatment, while counteracting some of their severe side effects.” https://www.ncbi.nlm.nih.gov/pubmed/30019449

“During the last few decades, a large body of evidence has accumulated to suggest endocannabinoids, phytocannabinoids and synthetic cannabinoids exert an inhibitory effect on cancer growth via blockade of cell proliferation and induction of apoptosis. Some studies support the hypothesis that cannabinoids may enhance immune responses against the progressive growth and spread of tumours.”  https://bpspubs.onlinelibrary.wiley.com/doi/full/10.1111/bph.14426#bph14426-fig-0001
“Previous research has shown that cannabinoids can help lessen side effects of anti-cancer therapies. Now a new British Journal of Pharmacology review has examined their potential for the direct treatment of cancer. Studies have shown that cannabinoids may stop cancer cells from dividing and invading normal tissue, and they may block the blood supply to tumors. Some studies also indicate that cannabinoids may enhance the body’s immune response against the growth and spread of tumors.” https://www.eurasiareview.com/19072018-cannabinoids-may-have-a-vast-array-of-anti-cancer-effects/
“Cannabinoids may have a vast array of anti-cancer effects” https://www.sciencedaily.com/releases/2018/07/180718082143.htm

“Cannabinoids may have a vast array of anti-cancer effects”  https://www.eurekalert.org/pub_releases/2018-07/w-cmh071718.php

Marijuana may help fight cancer” https://nypost.com/2018/07/18/marijuana-may-help-fight-cancer/

“Cannabis stops cancer spreading and boosts immune system, say scientists. Studies show cannabinoids can stop cancer cells from dividing and spreading, and blocks blood supply to tumours” https://www.plymouthherald.co.uk/news/health/cannabis-can-cure-cancer-proof-1803485
“Cannabis stops cancer spreading and boosts immune system, say scientists. Cannabis can act as a treatment for cancer and boost the immune system, claims a new study.” https://www.devonlive.com/news/health/cannabis-can-cure-cancer-proof-1803485
“Cannabis stops cancer spreading and boosts immune system, say scientists. Cannabis can act as a treatment for cancer and boost the immune system, claims a new study.” https://www.cornwalllive.com/news/uk-world-news/cannabis-can-cure-cancer-proof-1803485
Cannabis ‘can act as a treatment for cancer’. Cannabis can enhance the immune system and act as a treatment for cancer, claims a new study. Scientists at Rostock University Medical Centre in Germany claimed the benefits following a review of more than 100 studies.” https://www.thelondoneconomic.com/news/cannabis-can-act-as-a-treatment-for-cancer/19/07/

INSIGHT ON THE IMPACT OF ENDOCANNABINOID SYSTEM IN CANCER: A REVIEW.

British Journal of Pharmacology banner

“In the last decades, the endocannabinoid system has attracted a great interest in medicine and cancer disease is probably one of its most promising therapeutic areas.

On the one hand, endocannabinoid system expression has been found altered in numerous types of tumours compared to healthy tissue, and this aberrant expression has been related to cancer prognosis and disease outcome, suggesting a role of this system in tumour growth and progression that depends on cancer type.

On the other hand, it has been reported that cannabinoids exert an anticancer activity by inhibiting the proliferation, migration and/or invasion of cancer cells; and also tumour angiogenesis.

The endocannabinoid system may be considered as a new therapeutic target, although further studies to fully establish the effect of cannabinoids on tumour progression remain necessary.”

https://www.ncbi.nlm.nih.gov/pubmed/29663308

A Review of the Therapeutic Antitumor Potential of Cannabinoids.

:Image result for J Altern Complement Med.

“The aim of this review is to discuss cannabinoids from a preclinical and clinical oncological perspective and provide the audience with a concise, retrospective overview of the most significant findings concerning the potential use of cannabinoids in cancer treatment.

RESULTS:

Cannabis sativa is a plant rich in more than 100 types of cannabinoids. Besides exogenous plant cannabinoids, mammalian endocannabinoids and synthetic cannabinoid analogues have been identified. Cannabinoid receptors type 1 (CB1) and type 2 (CB2) have been isolated and characterized from mammalian cells. Through cannabinoid receptor and non-receptor signaling pathways, cannabinoids show specific cytotoxicity against tumor cells, while protecting healthy tissue from apoptosis. The dual antiproliferative and proapoptotic effects of cannabinoids and associated signaling pathways have been investigated on a large panel of cancer cell lines. Cannabinoids also display potent anticancer activity against tumor xenografts, including tumors that express high resistance to standard chemotherapeutics. Few studies have investigated the possible synergistic effects of cannabinoids with standard oncology therapies, and are based on the preclinically confirmed concept of “cannabinoid sensitizers.” Also, clinical trials aimed to confirm the antineoplastic activity of cannabinoids have only been evaluated on a small number of subjects, with no consensus conclusions regarding their effectiveness.

CONCLUSIONS:

A large number of cannabinoid compounds have been discovered, developed, and used to study the effects of cannabinoids on cancers in model systems. However, few clinical trials have been conducted on the use of cannabinoids in the treatment of cancers in humans. Further studies require extensive monitoring of the effects of cannabinoids alone or in combination with standard anticancer strategies. With such knowledge, cannabinoids could become a therapy of choice in contemporary oncology.”

Cannabinoids as Modulators of Cell Death: Clinical Applications and Future Directions.

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“Endocannabinoids are bioactive lipids that modulate various physiological processes through G-protein-coupled receptors (CB1 and CB2) and other putative targets. By sharing the activation of the same receptors, some phytocannabinoids and a multitude of synthetic cannabinoids mimic the effects of endocannabinoids.

In recent years, a growing interest has been dedicated to the study of cannabinoids properties for their analgesic, antioxidant, anti-inflammatory and neuroprotective effects. In addition to these well-recognized effects, various studies suggest that cannabinoids may affect cell survival, cell proliferation or cell death. These observations indicate that cannabinoids may play an important role in the regulation of cellular homeostasis and, thus, may contribute to tissue remodelling and cancer treatment.

For a long time, the study of cannabinoid receptor signalling has been focused on the classical adenylyl cyclase/cyclic AMP/protein kinase A (PKA) pathway. However, this pathway does not totally explain the wide array of biological responses to cannabinoids. In addition, the diversity of receptors and signalling pathways that endocannabinoids modulate offers an interesting opportunity for the development of specific molecules to disturb selectively the endogenous system.

Moreover, emerging evidences suggest that cannabinoids ability to limit cell proliferation and to induce tumour-selective cell death may offer a novel strategy in cancer treatment.

This review describes the main properties of cannabinoids in cell death and attempts to clarify the different pathways triggered by these compounds that may help to understand the complexity of respective molecular mechanisms and explore the potential clinical benefit of cannabinoids use in cancer therapies.”

https://www.ncbi.nlm.nih.gov/pubmed/28425013

Hybrid inhibitor of peripheral cannabinoid-1 receptors and inducible nitric oxide synthase mitigates liver fibrosis.

“Liver fibrosis, a consequence of chronic liver injury and a way station to cirrhosis and hepatocellular carcinoma, lacks effective treatment.

Endocannabinoids acting via cannabinoid-1 receptors (CB1R) induce profibrotic gene expression and promote pathologies that predispose to liver fibrosis.

CB1R antagonists produce opposite effects, but their therapeutic development was halted due to neuropsychiatric side effects. Inducible nitric oxide synthase (iNOS) also promotes liver fibrosis and its underlying pathologies, but iNOS inhibitors tested to date showed limited therapeutic efficacy in inflammatory diseases.

Here, we introduce a peripherally restricted, orally bioavailable CB1R antagonist, which accumulates in liver to release an iNOS inhibitory leaving group.

Additionally, it was able to slow fibrosis progression and to attenuate established fibrosis. Thus, dual-target peripheral CB1R/iNOS antagonists have therapeutic potential in liver fibrosis.

For multifactorial chronic diseases, such as fibrosis, the conventional pharmacological approach based on the “one-disease/one-target/one-drug” paradigm limits therapeutic efficacy and could be improved by simultaneously hitting multiple therapeutic targets.

One such target is the endocannabinoid/cannabinoid-1 receptor (endocannabinoid/CB1R) system.

The dual targeting of peripheral CB1R and iNOS demonstrated here exemplifies the therapeutic gain obtained by simultaneously hitting more than one molecule, which could then engage distinct as well as convergent cellular pathways. The advantage of such an approach is highlighted by emerging experience with recently developed antifibrotic medications, which indicates that targeting a single pathway has limited effect on fibrotic diseases .

Thus, the approach illustrated by the present study has promise as an effective antifibrotic strategy.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4979564/

Hybrid inhibitor of peripheral cannabinoid-1 receptors and inducible nitric oxide synthase mitigates liver fibrosis

“Liver fibrosis, a consequence of chronic liver injury and a way station to cirrhosis and hepatocellular carcinoma, lacks effective treatment.

Endocannabinoids acting via cannabinoid-1 receptors (CB1R) induce profibrotic gene expression and promote pathologies that predispose to liver fibrosis. CB1R antagonists produce opposite effects, but their therapeutic development was halted due to neuropsychiatric side effects.

Inducible nitric oxide synthase (iNOS) also promotes liver fibrosis and its underlying pathologies, but iNOS inhibitors tested to date showed limited therapeutic efficacy in inflammatory diseases.

Here, we introduce a peripherally restricted, orally bioavailable CB1R antagonist, which accumulates in liver to release an iNOS inhibitory leaving group.

Additionally, it was able to slow fibrosis progression and to attenuate established fibrosis. Thus, dual-target peripheral CB1R/iNOS antagonists have therapeutic potential in liver fibrosis.

Regarding the pharmacodynamics of the hybrid CB1R/iNOS inhibitor, two important principles have emerged from efforts to develop effective antifibrotic therapies. First, antifibrotic treatment strategies could aim to control the primary disease, to inhibit fibrogenic gene expression and signaling, to promote molecular mechanisms involved in fibrosis regression, or a combination of these. Second, with multiple molecular mechanisms and signaling pathways involved in fibrosis, targeting more than one could increase antifibrotic efficacy, and the hybrid CB1R/iNOS inhibitor embodies optimal characteristics on both accounts.

As to the first principle, both the endocannabinoid/CB1R system and iNOS are ideal targets, as they are known to be involved directly in the fibrotic process and also in the conditions predisposing to liver fibrosis, as detailed in the Introduction. An emerging major predisposing factor to liver fibrosis is nonalcoholic fatty liver disease, and CB1R blockade has proven effective in mitigating obesity-related hepatic steatosis in both rodent models and humans. The other two major predisposing factors, alcoholic fatty liver disease and viral hepatitis, also involve increased CB1R activity. Hepatic CB1R expression is induced either by chronic ethanol intake or the hepatitis C virus, and CB1R blockade mitigates alcohol-induced steatosis and inhibits hepatitis C virus production.

The dual targeting of peripheral CB1R and iNOS demonstrated here exemplifies the therapeutic gain obtained by simultaneously hitting more than one molecule, which could then engage distinct as well as convergent cellular pathways. The advantage of such an approach is highlighted by emerging experience with recently developed antifibrotic medications, which indicates that targeting a single pathway has limited effect on fibrotic diseases.

Thus, the approach illustrated by the present study has promise as an effective antifibrotic strategy.”

http://insight.jci.org/articles/view/87336