Tag Archives: agonists

Modulation of breast cancer cell viability by a cannabinoid receptor 2 agonist, JWH-015, is calcium dependent

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“Cannabinoid compounds, both nonspecific as well as agonists selective for either cannabinoid receptor 1 (CB1) or cannabinoid receptor 2 (CB2), have been shown to modulate the tumor microenvironment by inducing apoptosis in tumor cells in several model systems.

The mechanism of this modulation remains only partially delineated, and activity induced via the CB1 and CB2 receptors may be distinct despite significant sequence homology and structural similarity of ligands.

The results of this work characterize the actions of a CB2-selective agonist on breast cancer cells in a syngeneic murine model representing how a clinical presentation of cancer progression and metastasis may be significantly modulated by a G-protein-coupled receptor.”

https://www.dovepress.com/modulation-of-breast-cancer-cell-viability-by-a-cannabinoid-receptor-2-peer-reviewed-article-BCTT

WHERE’s MY ENTOURAGE? THE CURIOUS CASE OF 2-oleoylglycerol, 2-linolenoylglycerol, and 2-palmitoylglycerol.

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“2-arachidonoylglycerol (2-AG) is the most abundant endogenous cannabinoid in the brain and an agonist at two cannabinoid receptors (CB1 and CB2). The synthesis, degradation and signaling of 2-AG have been investigated in detail but its relationship to other endogenous monoacylglycerols has not been fully explored.

Three congeners that have been isolated from the CNS are 2-linoleoylglycerol (2-LG), 2-oleoylglycerol (2-OG), and 2-palmitoylglycerol (2-PG). These lipids do not orthosterically bind to cannabinoid receptors but are reported to potentiate the activity of 2-AG, possibly through inhibition of 2-AG degradation. This phenomenon has been dubbed the ‘entourage effect’ and has been proposed to regulate synaptic activity of 2-AG. To clarify the activity of these congeners of 2-AG we tested them in neuronal and cell-based signaling assays.

The signaling profile for these compounds is inconsistent with an entourage effect. None of the compounds inhibited neurotransmission via CB1 in autaptic neurons. Interestingly, each failed to potentiate 2-AG-mediated depolarization-induced suppression of excitation (DSE), behaving instead as antagonists. Examining other signaling pathways we found that 2-OG interferes with agonist-induced CB1 internalization while 2-PG modestly internalizes CB1 receptors. However in tests of pERK, cAMP and arrestin recruitment, none of the acylglycerols altered CB1 signaling.

Our results suggest 1) that these compounds do not serve as entourage compounds under the conditions examined, and 2) that they may instead serve as functional antagonists. Our results suggest that the relationship between 2-AG and its congeners is more nuanced than previously appreciated.”

http://www.ncbi.nlm.nih.gov/pubmed/27117667

Advances towards the Discovery of GPR55 Ligands.

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“The G-protein-coupled receptor 55 (GPR55) was identified in 1999.

It was proposed as a novel member of the endocannabinoid system due to the fact that some endogenous, plant-derived and synthetic cannabinoid ligands act on GPR55. However, the complexity of the cellular downstream signaling pathways related to GPR55 activation delayed the discovery of selective GPR55 ligands.

It was only a few years ago that the high throughput screening of libraries of pharmaceutical companies and governmental organizations allowed to identify selective GPR55 agonists and antagonists. Since then, several GPR55 modulator scaffolds have been reported.

The relevance of GPR55 has been explored in diverse physiological and pathological processes revealing its role in inflammation, neuropathic pain, bone physiology, diabetes and cancer.

Considering GPR55 as a new promising therapeutic target, there is a clear need for new selective and potent GPR55 modulators. This review will address a current structural update of GPR55 ligands.”

http://www.ncbi.nlm.nih.gov/pubmed/27109575

Endocannabinoids signaling: Molecular mechanisms of liver regulation and diseases.

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“The endocannabinoid system (ECS) includes endocannabinoids (eCBs), cannabinoid (CB) receptors and the enzymes that are responsible for endocannabinoid production and metabolism. The ECS has been reported to be present in both brain and peripheral tissues.

Recent studies have indicated that eCBs and their receptors are involved in the development of various liver diseases. They were found to be altered in response to many danger factors.

It is generally accepted that eCB may exert a protective action via CB2 receptors in different liver diseases. However, eCBs have also been demonstrated to have pathogenic role via their CB1 receptors.

Although the therapeutic potential of CB1 receptor blockade in liver diseases is limited by its neuropsychiatric side effects, many studies have been conducted to search for novel, peripherally restricted CB1 antagonists or CB2 agonists, which may minimize their neuropsychiatric side effects in clinical use.

This review summarizes the current understanding of the ECS in liver diseases and provides evidence for the potential to develop new therapeutic strategies for the treatment of these liver diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/27100518

Anandamide and its metabolites: what are their roles in the kidney?

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 “Anandamide (AEA) is the N-acyl ethanolamide of arachidonic acid, an agonist of cannabinoid and non-cannabinoid receptors in the body. The kidneys are enriched in AEA and in enzymes that metabolize AEA, but the roles of AEA and its metabolites in the kidney remain poorly understood.

This system likely is involved in the regulation of renal blood flow and hemodynamics and of tubular sodium and fluid reabsorption. It may act as a neuromodulator of the renal sympathetic nervous system. AEA and its cyclooxygenase-2 metabolites, the prostamides, in the renal medulla may represent a unique antihypertensive system involved in the long-term control of blood pressure. AEA and its metabolites are also implicated as modulators of inflammation and mediators of signaling in inflammation.

AEA and its metabolites may be influential in chronic kidney disease states associated with inflammation and cardiovascular diseases associated with hyperhomocysteinemia. The current knowledge of the roles of AEA and its derivatives highlights the need for further research to define and potentially exploit the role of this endocannabinoid system in the kidney.”

http://www.ncbi.nlm.nih.gov/pubmed/27100705

ENDOCANNABINOID SYSTEM: A multi-facet therapeutic target.

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Image result for Curr Clin Pharmacol.

“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

The role of carbon monoxide on the anti-nociceptive effects and expression of cannabinoid 2 receptors during painful diabetic neuropathy in mice.

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“The activation of cannabinoid 2 receptors (CB2R) attenuates chronic pain, but the role played by carbon monoxide synthesized by the inducible heme oxygenase 1 (HO-1) on the anti-nociceptive effects produced by a selective CB2R agonist, JWH-015, during painful diabetic neuropathy remains unknown.

The activation of HO-1 enhanced the anti-nociceptive effects of JWH-015 in diabetic mice, suggesting that coadministration of JWH-015 with CORM-2 or CoPP might be an interesting approach for the treatment of painful diabetic neuropathy in mice.”

http://www.ncbi.nlm.nih.gov/pubmed/27020787

Stimulation of brain glucose uptake by cannabinoid CB2 receptors and its therapeutic potential in Alzheimer’s disease.

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“Cannabinoid CB2 receptors (CB2Rs) are emerging as important therapeutic targets in brain disorders that typically involve neurometabolic alterations. We here addressed the possible role of CB2Rs in the regulation of glucose uptake in the mouse brain.

Together, these results reveal a novel general glucoregulatory role for CB2Rs in the brain, raising therapeutic interest in CB2R agonists as nootropic agents.”

http://www.ncbi.nlm.nih.gov/pubmed/26976670

[Role of cannabinoid receptors in renal diseases].

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“Chronic kidney disease remains a major challenge for public health systems and corresponds to the replacement of renal functional tissue by extracellular matrix proteins such as collagens and fibronectin. There is no efficient treatment to date for chronic kidney disease except nephroprotective strategies.

The cannabinoid system and more specifically the cannabinoid receptors 1 (CB1) and 2 (CB2) may represent a new therapeutic target in chronic kidney disease.

Experimental data obtained in models of diabetes and obesity suggested that CB1 blockade and CB2 stimulation may slow the development of diabetic nephropathy.

In human kidneys, CB1 expression is increased in various chronic nephropathies and correlates with renal function. Moreover, endogenous CB1 and CB2 ligands are greatly increased during renal fibrogenesis. A microarray analysis performed in an experimental model of renal fibrosis found that the gene encoding for the CB1 receptor was among the most upregulated genes. We also demonstrated that renal fibrogenesis could be reduced by CB1 inhibition and CB2 stimulation in an experimental model through a direct mechanism involving CB1 on myofibroblasts, which are the major effector cells during renal fibrosis.

Therefore, CB1 blockers may represent a novel therapeutic target in chronic kidney disease and diabetes.”

http://www.ncbi.nlm.nih.gov/pubmed/26968477

Cannabinoids inhibit insulin receptor signaling in pancreatic β-cells.

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“Optimal glucose homeostasis requires exquisitely precise adaptation of the number of insulin-secreting β-cells in the islets of Langerhans. Insulin itself positively regulates β-cell proliferation in an autocrine manner through the insulin receptor (IR) signaling pathway.

It is now coming to light that cannabinoid 1 receptor (CB1R) agonism/antagonism influences insulin action in insulin-sensitive tissues. However, the cells on which the CB1Rs are expressed and their function in islets have not been firmly established. We undertook the current study to investigate if intraislet endogenous cannabinoids (ECs) regulate β-cell proliferation and if they influence insulin action.

These findings provide direct evidence for a functional interaction between CB1R and IR signaling involved in the regulation of β-cell proliferation and will serve as a basis for developing new therapeutic interventions to enhance β-cell function and proliferation in diabetes.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3064093/