Inhibition of human tumour prostate PC-3 cell growth by cannabinoids R(+)-Methanandamide and JWH-015: Involvement of CB2

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“We have previously shown that cannabinoids induce growth inhibition and apoptosis in prostate cancer PC-3 cells, which express high levels of cannabinoid receptor types 1 and 2 (CB1 and CB2). In this study, we investigated the role of CB2 receptor in the anti-proliferative action of cannabinoids and the signal transduction triggered by receptor ligation.

This study defines the involvement of CB2-mediated signalling in the in vivo and in vitro growth inhibition of prostate cancer cells and suggests that CB2 agonists have potential therapeutic interest and deserve to be explored in the management of prostate cancer.

Cannabinoids, the active components of Cannabis sativa and their derivatives, exert a wide spectrum of modulatory actions and pharmacological activities in the brain as well as in the periphery, and therefore, the therapeutic potential of cannabinoids has gained much attention during the past few years. One of the most exciting areas of current research in the therapeutic potential of cannabinoids is cancer.

Recent evidence suggests that cannabinoids are powerful regulators of cell growth and differentiation. They have been shown to exert anti-tumoural effects by decreasing viability, proliferation, adhesion and migration on various cancer cells, thereby suggesting the potential use of cannabinoids in the treatment of gliomas, prostate and breast cancers and malignancies of immune origin.

Overall, our data show a role for the cannabinoid receptor CB2 in the anti-tumour effect of cannabinoids on prostate cells in vitroand in vivo. There is considerable interest in the application of selective CB2 receptor agonists, which are devoid of typical marijuana-like psychoactive properties of CB1 agonists, for future cannabinoid-based anticancer therapies. Therefore, our findings point to the potential application of cannabinoid receptor type 2 ligands as anti-tumour agents in prostate cancer.”

Current Status and Prospects for Cannabidiol Preparations as New Therapeutic Agents.

“There is growing pressure for states and the federal government to legalize the use of cannabis products for medical purposes in the United States.

Sixteen states have legalized (or decriminalized possession of) products high in cannabidiol (CBD) and with restricted Δ9 -tetrahydrocannabinol (Δ9 -THC) content. In most of these states, the intent is for use in refractory epileptic seizures in children, but in a few states, the indications are broader.

The objectives of this review are to provide an overview of the pharmacology and toxicology of CBD; to summarize some of the regulatory, safety, and cultural issues relevant to the further exploitation of its antiepileptic or other pharmacologic activities; and to assess the current status and prospects for clinical development of CBD and CBD-rich preparations for medical use in the United States.

Unlike Δ9 -THC, CBD elicits its pharmacologic effects without exerting any significant intrinsic activity on the cannabinoid receptors (CB1 and CB2 ), whose activation results in the psychotropic effects characteristic of Δ9 -THC, and CBD possesses several pharmacologic activities that give it a high potential for therapeutic use.

CBD exhibits antiepileptic, anxiolytic, antipsychotic, and antiinflammatory properties.

In combination with Δ9 -THC, CBD has received regulatory approvals in several European countries and is currently under study in U.S. Food and Drug Administration-registered trials in the United States.

A number of states have passed legislation to allow for the use of CBD-rich, limited Δ9 -THC-content preparations of cannabis for certain pathologic conditions. CBD is currently being studied in several clinical trials and is at different stages of clinical development for various medical indications.

Judging from clinical findings reported so far, CBD and CBD-enriched preparations have great potential utility, but uncertainties regarding sourcing, long-term safety, abuse potential, and regulatory dilemmas remain.”

http://www.ncbi.nlm.nih.gov/pubmed/27285147

Assay of DAGLα/β Activity.

“The endocannabinoid 2-arachidonoylglycerol (2-AG) exerts its physiological action by binding to and functionally activating type-1 (CB1) and type-2 (CB2) cannabinoid receptors. It is thought to be produced through the action of sn-1 selective diacylglycerol lipase (DAGL) that catalyzes 2-AG biosynthesis from sn-2-arachidonate-containing diacylglycerols. Since 2-AG biosynthetic enzymes have been identified only recently, little information on methodological approaches for measuring DAGL activity is as yet available. Here, a highly sensitive radiometric assay to measure DAGL activity by using 1-oleoyl[1-(14)C]-2-arachidonoylglycerol as the substrate is reported. All the steps needed to perform lipid extraction, fractionation by thin-layer chromatography (TLC), and quantification of radiolabeled [(14)C]-oleic acid via scintillation counting are described in detail.”

http://www.ncbi.nlm.nih.gov/pubmed/27245901

Protocol to Study β-Arrestin Recruitment by CB1 and CB2 Cannabinoid Receptors.

“Cannabinoid CB1 and CB2 receptors are G-protein-coupled receptors (GPCRs) that recruit β-arrestins upon activation by (partial) agonists. β-Arrestin recruitment is induced by phosphorylation of their C-terminal tails, and is associated with the termination of GPCR signaling; yet, it may also activate cellular signaling pathways independent of G-proteins. Here, we describe a detailed protocol to characterize the potency and efficacy of ligands to induce or inhibit β-arrestin recruitment to the human CB1 and CB2 receptors, by using the PathHunter(®) assay. The latter is a cellular assay that can be performed in plates with 384-wells. The PathHunter(®) assay makes use of β-galactosidase complementation, and has a chemiluminescent readout. We used this assay to characterize a set of reference ligands (both agonists and antagonists) on human CB1 and CB2 receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27245896

Endocannabinoid system: a promising therapeutic target for the treatment of haematological malignancies?

“The therapeutic properties of cannabinoids are well-known since ancient years.

Growing evidence exist on endocannabinoid system (ECS) modulation related with human tumorigenesis.

Taking into account the substantial role of ECS on immune cell regulation, the present review is aimed to summarize the emerging evidence concerning cannabinoid receptor (CBR) expression and cannabinoid ligand effects on haematological malignancies.

CONCLUSIONS:

Most of cannabinoid actions, mainly CB2R-mediated against haematopoietic malignant cells, seems promising, as inhibition of cell proliferation and apoptosis and paraptosis induction have been documented.

Cannabinoid ligands appear to activate rudimentary pathways for cell survival, such as ERK, JNK, p38 MAPK, and to induce caspase synthesis, in vitro. Such data are strongly recommended to be confirmed by in vivo experiments with emphasis on cannabinoid ligands’ bioavailability and phytocannabinoid psychotropic properties.

The preliminary antitumoral ECS effects and their relative lack of important side effects render ECS a promising therapeutic target for the treatment of haematological malignancies.”

http://www.ncbi.nlm.nih.gov/pubmed/27237820

Anti-inflammatory and antioxidant effects of a combination of cannabidiol and moringin in LPS-stimulated macrophages.

“Inflammatory response plays an important role in the activation and progress of many debilitating diseases. Natural products, like cannabidiol, a constituent of Cannabis sativa, and moringin, an isothiocyanate obtained from myrosinase-mediated hydrolysis of the glucosinolate precursor glucomoringin present in Moringa oleifera seeds, are well known antioxidants also endowed with anti-inflammatory activity.

This is due to a covalent-based mechanism for ITC, while non-covalent interactions underlie the activity of CBD. Since these two mechanisms are distinct, and the molecular endpoints are potentially complementary, we investigated in a comparative way the protective effect of these compounds alone or in combination on lipopolysaccharide-stimulated murine macrophages.

Our results show that the cannabidiol (5μM) and moringin (5μM) combination outperformed the single constituents that, at this dosage had only a moderate efficacy on inflammatory (Tumor necrosis factor-α, Interleukin-10) and oxidative markers (inducible nitric oxide synthase, nuclear factor erythroid 2-related factor 2, nitrotyrosine). Significant upregulation of Bcl-2 and downregulation of Bax and cleaved caspase-3 was observed in cells treated with cannabidiol-moringin combination.

Treatment with the transient receptor potential vanilloid receptor 1 antagonist was detrimental for the efficacy of cannabidiol, while no effect was elicited by cannabinoid receptor 1 and cannabinoid receptor 2 antagonists. None of these receptors was involved in the activity of moringin.

Taken together, our in vitro results testify the anti-inflammatory, antioxidative, and anti-apoptotic effects of the combination of cannabidiol and moringin.”

http://www.ncbi.nlm.nih.gov/pubmed/27215129

Synthetic cannabinoid receptor agonists and antagonists: implication in CNS disorders.

“Since the discovery of the cannabinoid receptors, numerous studies associate the endocannabinoid system with several physiological and pathological processes including cancer, appetite, fertility, memory, neuropathic and inflammatory pain, obesity, and neurodegenerative diseases.

Over the last two decades, several researches have been dedicated extensively on the cannabinoid receptors ligands since the direct activation of cannabinoid receptors results in several beneficial effects, in the brain and in the periphery.

During past years, cannabinoid CB1 and CB2 receptor ligands from plants or lab were rapidly developed and then various new structures were reported to be cannabinoids.

The CB1 and CB2 receptor ligands offer several therapeutic opportunities for several CNS-related diseases.

Based on the scientific literature, this review provides an overview of CB1 and CB2 receptor synthetic ligands obtained from drug research and in particular those synthesized for therapeutic purposes and potential clinical applications for central nervous system disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/27193072

Opposite roles of cannabinoid receptors 1 and 2 in hepatocarcinogenesis.

“The endocannabinoid system (ECS) exerts key roles in the development of liver fibrosis and fatty liver, two diseases that promote the development of hepatocellular carcinoma (HCC).

Although cannabinoids exert potent antitumour effects in vitro, the contribution of the ECS to carcinogenesis in vivo remains elusive.

CONCLUSIONS:

Similar to their role in fibrogenesis, CB1 and CB2 exert opposite effects on hepatocarcinogenesis and may provide novel therapeutic targets.”

http://www.ncbi.nlm.nih.gov/pubmed/27196571

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

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“Breast cancer is the leading cause of cancer-related deaths among women aged 34–50 worldwide, and is the most commonly diagnosed metastasizing tumor in women of all ages. Despite advances in understanding breast cancer as a disease, there remains a critical need for novel disease-modifying therapeutics.

Nonspecific cannabinoids, cannabinoid receptor 2 (CB2)-selective, as well as cannabinoid receptor 1 (CB1)-selective compounds have yielded similar antitumor results in several tumor models. The lack of neuronal expression of CB2 receptors precludes CB2 selective compounds from inducing the psychotropic effects that typically accompany CB1 activation.

 Our group and others have shown that CB2 agonists displaying selectivity for the CB2 receptor can decrease tumor cell viability and significantly attenuate cancer-induced bone pain without displaying psychoactive or addictive properties.

…antitumor effects of cannabinoids have been demonstrated in a variety of tumor models…

The antiproliferative effects of a CB2 agonist along with our previous work demonstrating significant efficacy in inhibiting bone cancer pain and slowing bone loss in a murine model of advanced breast cancer strongly suggest that CB2 agonists should be investigated in humans as adjunct therapy for advanced stages of breast cancer.

 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 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.
Several groups have shown that both nonselective cannabinoid and CB2-specific compounds decrease breast cancer viability in vitro and in vivo: Δ9-tetrahydrocannabinol and CB2-selective agonist, JWH-133, have been demonstrated to exert considerable antitumoral effects…”

Phytocannabinoids and cannabimimetic drugs: recent patents in central nervous system disorders.

“Starting from the chemical structure of phytocannabinoids, isolated from Cannabis sativa plant, research groups designed numerous cannabimimetic drugs.

These compounds according to their activities can be partial, full agonists and antagonists of cannabinoid receptors.

Anecdotal reports and scientific studies described beneficial properties of cannabinoids and their derivatives in several pathological conditions like neurological and neuropsychiatric disorders, and in many other diseases ranging from cancer, atherosclerosis, stroke, hypertension, inflammatory related disorders, and autoimmune diseases.

The cannabinoid CB1 receptor was considered particularly interesting for therapeutic approaches in neurological diseases, because primarily expressed by neurons of the central nervous system. In many experimental models, these drugs act via this receptor, however, CB1 receptor independent mechanisms have been also described. Furthermore, endogenous ligands of cannabinoid receptors, the endocannabinoids, are potent modulators of the synaptic function in the brain. In neurological diseases, numerous studies reported modulation of the levels of endocannabinoids according to the phase of the disease and its progression.

CONCLUSIONS:

Finally, although the study of the mechanisms of action of these compounds is still unsolved, many reports and patents strongly suggest therapeutic potential of these compounds in neurological diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/27184693