Cannabinoid receptor activation inhibits cell cycle progression by modulating 14-3-3β.

“Cannabinoids display various pharmacological activities, including tumor regression, anti-inflammatory and neuroprotective effects.

To investigate the molecular mechanisms underlying the pharmacological effects of cannabinoids, we used a yeast two-hybrid system to screen a mouse brain cDNA library for proteins interacting with type 1 cannabinoid receptor (CB1R). Using the intracellular loop 3 of CB1R as bait, we identified 14-3-3β as an interacting partner of CB1R and confirmed their interaction using affinity-binding assays. 14-3-3β has been reported to induce a cell cycle delay at the G2/M phase.

We tested the effects of cannabinoids on cell cycle progression in HeLa cells synchronized using a double-thymidine block-and-release protocol and found an increase in the population of G2/M phase cells. We further found that CB1R activation augmented the interaction of 14-3-3β with Wee1 and Cdc25B, and promoted phosphorylation of Cdc2 at Tyr-15.

These results suggest that cannabinoids induce cell cycle delay at the G2/M phase by activating 14-3-3β.”

http://www.ncbi.nlm.nih.gov/pubmed/25002257

Endocannabinoid system as a regulator of tumor cell malignancy – biological pathways and clinical significance

“The endocannabinoid system (ECS) comprises cannabinoid receptors (CBs), endogenous cannabinoids, and enzymes responsible for their synthesis, transport, and degradation of (endo)cannabinoids.

To date, two CBs, CB1 and CB2, have been characterized; however, orphan G-protein-coupled receptor GPR55 has been suggested to be the third putative CB.

Several different types of cancer present abnormal expression of CBs, as well as other components of ECS, and this has been shown to correlate with the clinical outcome.

Although most effects of (endo)cannabinoids are mediated through stimulation of classical CBs, they also interact with several molecules, either prosurvival or proapoptotic molecules.

It should be noted that the mode of action of exogenous cannabinoids differs significantly from that of endocannabinoid and results from the studies on their activity both in vivo and in vitro could not be easily compared.

This review highlights the main signaling pathways involved in the antitumor activity of cannabinoids and the influence of their activation on cancer cell biology.

We also discuss changes in the expression pattern of the ECS in various cancer types that have an impact on disease progression and patient survival.

A growing amount of experimental data imply possible exploitation of cannabinoids in cancer therapy.”

https://www.dovepress.com/endocannabinoid-system-as-a-regulator-of-tumor-cell-malignancy-ndash-b-peer-reviewed-article-OTT

Inhibition of autophagy and enhancement of endoplasmic reticulum stress increase sensitivity of osteosarcoma Saos-2 cells to cannabinoid receptor agonist WIN55,212-2.

“WIN55,212-2, a cannabinoid receptor agonist, can activate cannabinoid receptors, which has proven anti-tumour effects in several tumour types. Studies showed that WIN can inhibit tumour cell proliferation and induce apoptosis in diverse cancers.

However, the role and mechanism of WIN in osteosarcoma are still unclear. In this study, we examined the effect of WIN55,212-2 on osteosarcoma cell line Saos-2 in terms of cell viability and apoptosis. Meanwhile, we further explored the role of endoplasmic reticulum stress and autophagy in apoptosis induced by WIN55,212-2.

Our results showed that the cell proliferation of Saos-2 was inhibited by WIN55,212-2 in a dose-dependent and time-dependent manner. WIN55,212-2-induced Saos-2 apoptosis through mitochondrial apoptosis pathway. Meanwhile, WIN55,212-2 can induce endoplasmic reticulum stress and autophagy in Saos-2 cells. Inhibition of autophagy and enhancement of endoplasmic reticulum stress increased apoptosis induced by WIN55,212-2 in Saos-2 cells.

These findings indicated that WIN55,212-2 in combination with autophagic inhibitor or endoplasmic reticulum stress activator may shed new light on osteosarcoma treatment.”

http://www.ncbi.nlm.nih.gov/pubmed/27309350

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.”

The Influence of Biomechanical Properties and Cannabinoids on Tumor Invasion.

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“Cannabinoids are known to have an anti-tumorous effect, but the underlying mechanisms are only sparsely understood. Mechanical characteristics of tumor cells represent a promising marker to distinguish between tumor cells and the healthy tissue.

We tested the hypothesis whether cannabinoids influence the tumor cell specific mechanical and migratory properties and if these factors are a prognostic marker for the invasiveness of tumor cells.

Here we could show that a “generalized stiffness” is a profound marker for the invasiveness of a tumor cell population in our model and thus might be of high clinical relevance for drug testing.

Additionally cannabinoids were shown to be of potential use for therapeutic approaches of glioblastoma.”

http://www.ncbi.nlm.nih.gov/pubmed/27149140

“Glioblastomas (GBM) are tumors that arise from astrocytes—the star-shaped cells that make up the “glue-like,” or supportive tissue of the brain. These tumors are usually highly malignant (cancerous) because the cells reproduce quickly and they are supported by a large network of blood vessels. Glioblastomas are generally found in the cerebral hemispheres of the brain, but can be found anywhere in the brain or spinal cord.”  http://www.abta.org/brain-tumor-information/types-of-tumors/glioblastoma.html?referrer=https://www.google.com/

Targeting Cannabinoid Receptors in Brain Tumors

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“Cannabinoids, the active components of Cannabis sativa L., act in the body by mimicking endogenous substances — the endocannabinoids — that activate specific cell surface receptors.

Cannabinoids exert various palliative effects in cancer patients. In addition, cannabinoids inhibit the growth of different types of tumor cells, including glioma cells, in laboratory animals. They do so by modulating key cell signaling pathways, mostly the endoplasmic reticulum stress response, thereby inducing antitumoral actions such as the apoptotic death of tumor cells and the inhibition of tumor angiogenesis.

Of interest, cannabinoids seem to be selective antitumoral compounds as they kill glioma cells but not their nontransformed astroglial counterparts.

On the basis of these preclinical findings, a pilot clinical study of Δ9-tetrahydrocannabinol (Δ9-THC) in patients with recurrent glioblastoma multiforme has been recently run. The fair safety profile of Δ9-THC, together with its possible growth-inhibiting action on tumor cells, may set the basis for future trials aimed at evaluating the potential antitumoral activity of cannabinoids.”

http://link.springer.com/chapter/10.1007%2F978-0-387-74349-3_17

Study: Cannabinoids Limit Neuroblastoma Cell Proliferation

Study: Cannabinoids Limit Neuroblastoma Cell Proliferation

“The administration of the cannabinoids THC and CBD limit cancer activity in neuroblastoma cells in culture and in animals, according to preclinical data published in the journal Current Oncology.

Neuroblastoma is an aggressive form of childhood cancer that often goes inadequately addressed by conventional treatment.

Investigators reported that both types of cannabinoids reduced neuroblastoma cell viability, but that CBD demonstrated superior anti-cancer ability. The study is the first to document the anti-cancer properties of CBD in this particular cancerous cell line.

They concluded, “Our findings about the activity of CBD in nbl (neuroblastoma) support and extend previous findings about the anti-tumor activities of CBD in other tumors and suggest that cannabis extracts enriched in CBD and not in THC could be suitable for the development of novel non-psychotropic therapeutic strategies in nbl.”  http://enewspf.com/2016/04/21/study-cannabinoids-limit-neuroblastoma-cell-proliferation/

“In vitro and in vivo efficacy of non-psychoactive cannabidiol in neuroblastoma”  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4791143/?report=reader

β-Caryophyllene potently inhibits solid tumor growth and lymph node metastasis of B16F10 melanoma cells in high-fat diet-induced obese C57BL/6N mice.

“…high-fat diet (HFD) feeding stimulated solid tumor growth and lymph node (LN) metastasis… β-caryophyllene (BCP) is a natural bicyclic sesquiterpene found in many essential oils and has been shown to exert anti-inflammatory activities….

BCP inhibits HFD-induced melanoma progression…

β-Caryophyllene potently inhibits solid tumor growth and lymph node metastasis of B16F10 melanoma cells in high-fat diet-induced obese C57BL/6N mice.” http://www.ncbi.nlm.nih.gov/pubmed/26025912

“β-caryophyllene (BCP) is a common constitute of the essential oils of numerous spice, food plants and major component in Cannabis.”  http://www.ncbi.nlm.nih.gov/pubmed/23138934

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

Dronabinol has preferential antileukemic activity in acute lymphoblastic and myeloid leukemia with lymphoid differentiation patterns

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“It has been previously demonstrated in several cancer models, that Dronabinol (THC) may have anti-tumor activity – however, controversial data exists for acute leukemia. We have anecdotal evidence that THC may have contributed to disease control in a patient with acute undifferentiated leukemia.

To test this hypothesis, we evaluated the antileukemic efficacy of THC in several leukemia cell lines and native leukemia blasts cultured ex vivo.

We here reveal a novel aspect of dronabinol, a cannabinoid derivative, which displays remarkable antiproliferative as well as proapoptotic efficacy in a distinct leukemia patient cohort – in vitro and in ex vivo native leukemia blasts. It has been previously reported that cannabinoids display anticancer properties. However, due to legal issues the use and exploration of such agents is highly limited in many countries.

Importantly, we demonstrate that antileukemic concentrations are achievable in vivo.

Our study provides rigorous data to support clinical evaluation of THC as a low-toxic therapy option in a well defined subset of acute leukemia patients.”

http://www.ncbi.nlm.nih.gov/pubmed/26775260

http://bmccancer.biomedcentral.com/articles/10.1186/s12885-015-2029-8

The stress-regulated protein p8 mediates cannabinoid-induced apoptosis of tumor cells.

“One of the most exciting areas of current research in the cannabinoid field is the study of the potential application of these compounds as antitumoral drugs. Here, we describe the signaling pathway that mediates cannabinoid-induced apoptosis of tumor cells. By using a wide array of experimental approaches, we identify the stress-regulated protein p8 (also designated as candidate of metastasis 1) as an essential mediator of cannabinoid antitumoral action and show that p8 upregulation is dependent on de novo-synthesized ceramide. We also observe that p8 mediates its apoptotic effect via upregulation of the endoplasmic reticulum stress-related genes ATF-4, CHOP, and TRB3. Activation of this pathway may constitute a potential therapeutic strategy for inhibiting tumor growth.”

http://www.ncbi.nlm.nih.gov/pubmed/16616335

“Marijuana has been used in medicine for many centuries, and nowadays there is a renaissance in the study of the therapeutic effects of cannabinoids. One of the most active areas of research in the cannabinoid field is the study of the potential antitumoral application of these drugs. Our results unravel the mechanism of cannabinoid antitumoral action by demonstrating the proapoptotic role of the stress protein p8 via its downstream targets ATF-4, CHOP, and TRB3.

The identification of this pathway may contribute to the design of therapeutic strategies for inhibiting tumor growth. In particular, our findings can help to improve the efficiency and selectivity of potential antitumoral therapies with cannabinoids.

Our results also support that cannabinoid treatment does not activate this pathway in nontransformed cells, in line with the belief that cannabinoid proapoptotic action is selective for tumor versus nontumor cells, and that cannabinoids act in a synergic fashion with ER stress inducers as well as with other antitumoral agents.

The identification of the p8-regulated pathway described here may contribute to the design of therapeutic strategies for inhibiting tumor growth. In particular, our findings can help to improve the efficiency and selectivity of a potential cannabinoid-based antitumoral therapy.”

http://www.sciencedirect.com/science/article/pii/S1535610806000857