Targeting Peripherally Restricted Cannabinoid Receptor 1, Cannabinoid Receptor 2, and Endocannabinoid-Degrading Enzymes for the Treatment of Neuropathic Pain Including Neuropathic Orofacial Pain.

ijms-logo“Neuropathic pain conditions including neuropathic orofacial pain (NOP) are difficult to treat. Contemporary therapeutic agents for neuropathic pain are often ineffective in relieving pain and are associated with various adverse effects. Finding new options for treating neuropathic pain is a major priority in pain-related research.

Cannabinoid-based therapeutic strategies have emerged as promising new options.

Cannabinoids mainly act on cannabinoid 1 (CB1) and 2 (CB2) receptors, and the former is widely distributed in the brain. The therapeutic significance of cannabinoids is masked by their adverse effects including sedation, motor impairment, addiction and cognitive impairment, which are thought to be mediated by CB1 receptors in the brain. Alternative approaches have been developed to overcome this problem by selectively targeting CB2 receptors, peripherally restricted CB1 receptors and endocannabinoids that may be locally synthesized on demand at sites where their actions are pertinent.

Many preclinical studies have reported that these strategies are effective for treating neuropathic pain and produce no or minimal side effects.

Recently, we observed that inhibition of degradation of a major endocannabinoid, 2-arachydonoylglycerol, can attenuate NOP following trigeminal nerve injury in mice. This review will discuss the above-mentioned alternative approaches that show potential for treating neuropathic pain including NOP.”

https://www.ncbi.nlm.nih.gov/pubmed/32093166

https://www.mdpi.com/1422-0067/21/4/1423

The Endocannabinoid System Alleviates Pain in a Murine Model of Cancer-Induced Bone Pain.

Journal of Pharmacology and Experimental Therapeutics: 372 (3)“Metastatic breast cancer is prevalent worldwide, and one of the most common sites of metastasis are long bones. Of patients with disease, the major symptom is pain, yet current medications fail to adequately result in analgesic efficacy and present major undesirable adverse effects.

In our study we investigate the potential of a novel monoacylglycerol lipase (MAGL) inhibitor, MJN110, in a murine model of cancer induced bone pain (CIBP). Literature has previously demonstrated that MAGL inhibitors function to increase the endogenous concentrations of 2-arachydonylglycerol, which then activate CB1 and CB2 receptors inhibiting inflammation and pain.

Together, these data support the application for MJN110 as a novel therapeutic for cancer induced bone pain.

SIGNIFICANCE STATEMENT: Current standard of care for metastatic breast cancer pain is opioid-based therapies with adjunctive chemotherapy, which have highly addictive and other deleterious side effects. The need for effective, non-opioid based therapies is essential and harnessing the endogenous cannabinoid system is proving to be a new target to treat various types of pain conditions. We present a novel drug targeting the endogenous cannabinoid system that is effective at reducing pain in a mouse model of metastatic breast cancer to bone.”

https://www.ncbi.nlm.nih.gov/pubmed/32054717

http://jpet.aspetjournals.org/content/early/2020/02/13/jpet.119.262337

Cannabinoid receptor expression in non-small cell lung cancer. Effectiveness of tetrahydrocannabinol and cannabidiol inhibiting cell proliferation and epithelial-mesenchymal transition in vitro.

Image result for plos one “Patients with non-small cell lung cancer (NSCLC) develop resistance to antitumor agents by mechanisms that involve the epithelial-to-mesenchymal transition (EMT). This necessitates the development of new complementary drugs, e.g., cannabinoid receptors (CB1 and CB2) agonists including tetrahydrocannabinol (THC) and cannabidiol (CBD).

The combined use of THC and CBD confers greater benefits, as CBD enhances the effects of THC and reduces its psychotropic activity. We assessed the relationship between the expression levels of CB1 and CB2 to the clinical features of a cohort of patients with NSCLC, and the effect of THC and CBD (individually and in combination) on proliferation, EMT and migration in vitro in A549, H460 and H1792 lung cancer cell lines.

METHODS:

Expression levels of CB1, CB2, EGFR, CDH1, CDH2 and VIM were evaluated by quantitative reverse transcription-polymerase chain reaction. THC and CBD (10-100 μM), individually or in combination (1:1 ratio), were used for in vitro assays. Cell proliferation was determined by BrdU incorporation assay. Morphological changes in the cells were visualized by phase-contrast and fluorescence microscopy. Migration was studied by scratch recolonization induced by 20 ng/ml epidermal growth factor (EGF).

RESULTS:

The tumor samples were classified according to the level of expression of CB1, CB2, or both. Patients with high expression levels of CB1, CB2, and CB1/CB2 showed increased survival reaching significance for CB1 and CB1/CB2 (p = 0.035 and 0.025, respectively).

Both cannabinoid agonists inhibited the proliferation and expression of EGFR in lung cancer cells, and CBD potentiated the effect of THC. THC and CBD alone or in combination restored the epithelial phenotype, as evidenced by increased expression of CDH1 and reduced expression of CDH2 and VIM, as well as by fluorescence analysis of cellular cytoskeleton.

Finally, both cannabinoids reduced the in vitro migration of the three lung cancer cells lines used.

CONCLUSIONS:

The expression levels of CB1 and CB2 have a potential use as markers of survival in patients with NSCLC. THC and CBD inhibited the proliferation and expression of EGFR in the lung cancer cells studied. Finally, the THC/CBD combination restored the epithelial phenotype in vitro.”

https://www.ncbi.nlm.nih.gov/pubmed/32049991

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0228909

Cannabinoid Signaling in Glioma Cells.

 “Cannabinoids are a group of structurally heterogeneous but pharmacologically related compounds, including plant-derived cannabinoids, synthetic substances and endogenous cannabinoids, such as anandamide and 2-arachidonoylglycerol.

Cannabinoids elicit a wide range of central and peripheral effects mostly mediated through cannabinoid receptors. There are two types of specific Gi/o-protein-coupled receptors cloned so far, called CB1 and CB2, although an existence of additional cannabinoid-binding receptors has been suggested. CB1 and CB2 differ in their predicted amino acid sequence, tissue distribution, physiological role and signaling mechanisms.

Significant alterations of a balance in the cannabinoid system between the levels of endogenous ligands and their receptors occur during malignant transformation in various types of cancer, including gliomas.

Cannabinoids exert anti-proliferative action in tumor cells.

Induction of cell death by cannabinoid treatment relies on the generation of a pro-apoptotic sphingolipid ceramide and disruption of signaling pathways crucial for regulation of cellular proliferation, differentiation or apoptosis. Increased ceramide levels lead also to ER-stress and autophagy in drug-treated glioblastoma cells.

Beyond blocking of tumor cells proliferation cannabinoids inhibit invasiveness, angiogenesis and the stem cell-like properties of glioma cells, showing profound activity in the complex tumor microenvironment. Advances in translational research on cannabinoid signaling led to clinical investigations on the use of cannabinoids in treatments of glioblastomas.”

https://www.ncbi.nlm.nih.gov/pubmed/32034716

https://link.springer.com/chapter/10.1007%2F978-3-030-30651-9_11

“Cannabinoids exert anti-proliferative action in tumor cells.” https://www.ncbi.nlm.nih.gov/pubmed/22879071

“A glioma is a primary brain tumor that originates from the supportive cells of the brain, called glial cells.” http://neurosurgery.ucla.edu/body.cfm?id=159

“Remarkably, cannabinoids kill glioma cells selectively and can protect non-transformed glial cells from death.” http://www.ncbi.nlm.nih.gov/pubmed/15275820

Endocannabinoids as Therapeutic Targets.

Archives of Medical Research“Most of the drugs of abuse affect the brain by interacting with naturally expressed molecular receptors. Marihuana affects a series of receptors including cannabinoid receptor 1 (CB1R) and CB2R, among others. Endogenous molecules with cannabinoid activity interact with these receptors naturally. Receptors, ligands, synthesizing and degrading enzymes, as well as transporters, have been described.

This endocannabinoid system modulates behaviors and physiological processes, i.e. food intake, the sleep-waking cycle, learning and memory, motivation, and pain perception, among others. The rather broad distribution of endocannabinoids in the brain explains the different effects marihuana induces in its users. However, this very same anatomical and physiological distribution makes this system a useful target for therapeutic endeavors.

In this review, we briefly discuss the potential of small molecules that target the endocannabinoids as therapeutic tools to improve behaviors and treat illnesses. We believe that under medical supervision, endocannabinoid targets offer new advantages for patients for controlling multiple medical disorders.”

https://www.ncbi.nlm.nih.gov/pubmed/32028095

https://www.sciencedirect.com/science/article/abs/pii/S0188440919304746?via%3Dihub

The endocannabinoid receptors CB1 and CB2 affect the regenerative potential of adipose tissue MSCs.

Experimental Cell Research“Human adipose tissue includes large quantities of mesenchymal stromal cells (atMSCs), which represent an abundant cell source for therapeutic applications in the field of regenerative medicine.

Adipose tissue secrets various soluble factors including endocannabinoids, and atMSCs express the cannabinoid receptors CB1 and CB2. This indicates that adipose tissue possesses an endocannabinoid system (ECS). The ECS is also ascribed great significance for wound repair, e.g. by modulating inflammation. However, the exact effects of CB1/CB2 activation in human atMSCs have not been investigated, yet.

In the present study, we stimulated human atMSCs with increasing concentrations (1-30 μM) of the unspecific cannabinoid receptor ligand WIN55,212-2 and the specific CB2 agonist JWH-133, either alone or co-applied with the receptor antagonist Rimonabant (CB1) or AM 630 (CB2). We investigated the effects on metabolic activity, cell number, differentiation and cytokine release, which are important processes during tissue regeneration.

WIN decreased metabolic activity and cell number, which was reversed by Rimonabant. This suggests a CB1 dependent mechanism, whereas the number of atMSCs was increased after CB2 ligation. WIN and JWH increased the release of VEGF, TGF-β1 and HGF. Adipogenesis was enhanced by WIN, which could be reversed by blocking CB1. There was no effect on osteogenesis, and only WIN increased chondrogenic differentiation.

Our results indicate that definite activation of the cannabinoid receptors exerted different effects in atMSCs, which could be of specific value in cell-based therapy for wound regeneration.”

https://www.ncbi.nlm.nih.gov/pubmed/32006556

https://www.sciencedirect.com/science/article/abs/pii/S001448272030080X?via%3Dihub

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Cryo-EM Structure of the Human Cannabinoid Receptor CB2-Gi Signaling Complex.

Image result for cell journal“Drugs selectively targeting CB2 hold promise for treating neurodegenerative disorders, inflammation, and pain while avoiding psychotropic side effects mediated by CB1. The mechanisms underlying CB2 activation and signaling are poorly understood but critical for drug design. Here we report the cryo-EM structure of the human CB2-Gi signaling complex bound to the agonist WIN 55,212-2. The 3D structure reveals the binding mode of WIN 55,212-2 and structural determinants for distinguishing CB2 agonists from antagonists, which are supported by a pair of rationally designed agonist and antagonist. Further structural analyses with computational docking results uncover the differences between CB2 and CB1 in receptor activation, ligand recognition, and Gi coupling. These findings are expected to facilitate rational structure-based discovery of drugs targeting the cannabinoid system.”

https://www.ncbi.nlm.nih.gov/pubmed/32004460

https://www.cell.com/cell/fulltext/S0092-8674(20)30054-4?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867420300544%3Fshowall%3Dtrue

Activation and Signaling Mechanism Revealed by Cannabinoid Receptor-Gi Complex Structures.

Image result for cell journal“Human endocannabinoid systems modulate multiple physiological processes mainly through the activation of cannabinoid receptors CB1 and CB2. Their high sequence similarity, low agonist selectivity, and lack of activation and G protein-coupling knowledge have hindered the development of therapeutic applications. Importantly, missing structural information has significantly held back the development of promising CB2-selective agonist drugs for treating inflammatory and neuropathic pain without the psychoactivity of CB1. Here, we report the cryoelectron microscopy structures of synthetic cannabinoid-bound CB2 and CB1 in complex with Gi, as well as agonist-bound CB2 crystal structure. Of important scientific and therapeutic benefit, our results reveal a diverse activation and signaling mechanism, the structural basis of CB2-selective agonists design, and the unexpected interaction of cholesterol with CB1, suggestive of its endogenous allosteric modulating role.”

https://www.ncbi.nlm.nih.gov/pubmed/32004463

https://www.cell.com/cell/fulltext/S0092-8674(20)30055-6?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867420300556%3Fshowall%3Dtrue

Treatment with Cannabinoids as a Promising Approach for Impairing Fibroblast Activation and Prostate Cancer Progression.

ijms-logo “Endo-, phyto- and synthetic cannabinoids have been proposed as promising anti-cancer agents able to impair cancer cells’ behavior without affecting their non-transformed counterparts.

However, cancer outcome depends not only on cancer cells’ activity, but also on the stromal cells, which coevolve with cancer cells to sustain tumor progression.

Here, we show for the first time that cannabinoid treatment impairs the activation and the reactivity of cancer-associated fibroblasts (CAFs), the most represented stromal component of prostate tumor microenvironment.

Overall, our data strongly support the use of cannabinoids as anti-tumor agents in prostate cancer, since they are able to simultaneously strike both cancer and stromal cells.”

https://www.ncbi.nlm.nih.gov/pubmed/31991773

https://www.mdpi.com/1422-0067/21/3/787

Microglial Phenotypes and Their Relationship to the Cannabinoid System: Therapeutic Implications for Parkinson’s Disease.

 Image result for molecules journal“Parkinson’s disease is a neurodegenerative disorder, the motor symptoms of which are associated classically with Lewy body formation and nigrostriatal degeneration.

Neuroinflammation has been implicated in the progression of this disease, by which microglia become chronically activated in response to α-synuclein pathology and dying neurons, thereby acquiring dishomeostatic phenotypes that are cytotoxic and can cause further neuronal death.

Microglia have a functional endocannabinoid signaling system, expressing the cannabinoid receptors in addition to being capable of synthesizing and degrading endocannabinoids. Alterations in the cannabinoid system-particularly an upregulation in the immunomodulatory CB2 receptor-have been demonstrated to be related to the microglial activation state and hence the microglial phenotype.

This paper will review studies that examine the relationship between the cannabinoid system and microglial activation, and how this association could be manipulated for therapeutic benefit in Parkinson’s disease.”

https://www.ncbi.nlm.nih.gov/pubmed/31973235

“Microglia activation states and cannabinoid system: Therapeutic implications.  There is accumulating evidence indicating that cannabinoids (CBs) might serve as a promising tool to modify the outcome of inflammation, especially by influencing microglial activity. Microglia has a functional endocannabinoid (eCB) signaling system, composed of cannabinoid receptors and the complete machinery for the synthesis and degradation of eCBs. These actions make CBs a promising therapeutic tool to avoid the detrimental effects of inflammation and possibly paving the way to target microglia in order to generate a reparative milieu in neurodegenerative diseases.” https://www.ncbi.nlm.nih.gov/pubmed/27373505

“These findings imply that a hypofunction or a dysregulation of the endocannabinoid system may be responsible for some of the symptoms of these diseases. Scientific evidence shows that cannabis can provide symptomatic relief in several neurodegenerative diseases.” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4070159/

“Cannabinoids can have neuroprotective effects, and this can be exploited for therapeutic strategies against neurodegenerative diseases”   http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3243800/