Amphiregulin is a factor for resistance of glioma cells to cannabinoid-induced apoptosis.

“Gliomas, one of the most malignant forms of cancer, exhibit high resistance to conventional therapies. Identification of the molecular mechanisms responsible for this resistance is therefore of great interest to improve the efficacy of the treatments against these tumors. Delta9-Tetrahydrocannabinol (THC), the major active ingredient of marijuana, and other cannabinoids inhibit tumor growth in animal models of cancer, including glioma, an effect that relies, at least in part, on the ability of these compounds to induce apoptosis of tumor cells.

…we identified the epidermal growth factor receptor ligand amphiregulin as a candidate factor to mediate the resistance of glioma cells to cannabinoid treatment… in vivo silencing of amphiregulin rendered the resistant tumors xenografts sensitive to cannabinoid antitumoral action.

Amphiregulin expression was associated with increased extracellular signal-regulated kinase (ERK) activation, which mediated the resistance to THC by blunting the expression of p8 and TRB3-two genes involved in cannabinoid-induced apoptosis of glioma cells.

 Our findings therefore identify Amphirregulin as a factor for resistance of glioma cells to THC-induced apoptosis and contribute to unraveling the molecular bases underlying the emerging notion that targeted inhibition of the EGFR pathway can improve the efficacy of antitumoral therapies.”

http://www.ncbi.nlm.nih.gov/pubmed/19229996

Stimulation of the midkine/ALK axis renders glioma cells resistant to cannabinoid antitumoral action

“Δ9-Tetrahydrocannabinol (THC), the major active ingredient of marijuana, and other cannabinoids inhibit tumor growth in animal models of cancer, including glioma, an effect that relies, at least in part, on the stimulation of autophagy-mediated apoptosis in tumor cells. 

…Altogether, our findings identify Mdk as a pivotal factor involved in the resistance of glioma cells to THC pro-autophagic and antitumoral action, and suggest that selective targeting of the Mdk/ALK axis could help to improve the efficacy of antitumoral therapies for gliomas.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3131933/

Cannabidiol provides long-lasting protection against the deleterious effects of inflammation in a viral model of multiple sclerosis: A role for A2A receptors.

“Inflammation in the central nervous system (CNS) is a complex process that involves a multitude of molecules and effectors, and it requires the transmigration of blood leukocytes across the blood-brain barrier (BBB) and the activation of resident immune cells. Cannabidiol (CBD), a non-psychotropic cannabinoid constituent of Cannabis sativa, has potent anti-inflammatory and immunosuppressive properties.

 …Moreover, CBD administration at the time of viral infection exerts long-lasting effects, ameliorating motor deficits in the chronic phase of the disease in conjunction with reduced microglial activation and pro-inflammatory cytokine production. Adenosine A2A receptors participate in some of the anti-inflammatory effects of CBD…

Together, our findings highlight the anti-inflammatory effects of CBD in this viral model of MS, and demonstrate the significant therapeutic potential of this compound for the treatment of pathologies with an inflammatory component.”

http://www.ncbi.nlm.nih.gov/pubmed/23851307

Role of cannabinoid CB2 receptor in the reinforcing actions of ethanol.

“This study examines the role of the cannabinoid CB2 receptor (CB2 r) on the vulnerability to ethanol consumption… These results suggest that deletion of the CB2 r gene increased preference for and vulnerability to ethanol consumption…

Future studies will determine the role of CB2 r as a target for the treatment of problems related with alcohol consumption.”

http://www.ncbi.nlm.nih.gov/pubmed/23855434

Anti-inflammatory property of the cannabinoid receptor-2-selective agonist JWH-133 in a rodent model of autoimmune uveoretinitis.

“Previous studies have shown that cannabinoids have anti-inflammatory and immune-modulating effects, but the precise mechanisms of action remain to be elucidated.

In this study, we investigated the effect of JWH 133, a selective agonist for cannabinoid receptor 2, the main receptor expressed on immune cells, in a model of autoimmune disease, experimental autoimmune uveoretinitis (EAU).

JWH 133 suppressed EAU in a dose-dependent manner (0.015-15 mg/kg), and the suppressive effect could be achieved in the disease-induction stage and the effector stage. Leukocytes from mice, which had been treated with JWH 133, had diminished responses to retinal peptide and mitogen Con A stimulation in vitro. In vivo JWH 133 treatment also abrogated leukocyte cytokine/chemokine production. Further in vitro studies indicated that JWH 133 down-regulated the TLR4 via Myd88 signal transduction, which may be responsible for its moderate, suppressive effect on antigen presentation. In vivo JWH 133 treatment (1 mg/kg) also suppressed leukocyte trafficking (rolling and infiltration) in inflamed retina as a result of an effect on reducing adhesion molecules CD162 (P-selectin glycoprotein ligand 1) and CD11a (LFA-1) expression on T cells.

In conclusion, the cannabinoid agonist JWH 133 has a high in vivo, anti-inflammatory property and may exert its effect via inhibiting the activation and function of autoreactive T cells and preventing leukocyte trafficking into the inflamed tissue.”

Full text: http://www.jleukbio.org/content/82/3/532.long

1′,1′-Dimethylheptyl-delta-8-tetrahydrocannabinol-11-oic acid: a novel, orally effective cannabinoid with analgesic and anti-inflammatory properties.

“Chemical structures of Δ-9-THC (dronabinol), nabilone, and CT-3”

Figure 1

“1′,1′-Dimethylheptyl-Delta-8-tetrahydrocannabinol-11-oic acid (CT-3) is a novel cannabinoid that is under development by Atlantic Pharmaceuticals as an anti-inflammatory and analgesic drug.

The objective of the study was to investigate the effects of CT-3 on overt symptom complex (Irwin’s test), nociception, gastrointestinal (GI) ulceration, and pharmacological availability after intragastric (i.g.) and intraperitoneal (i.p.) administration.

  The evidence indicates that CT-3 exhibits a large dissociation between its anti-inflammatory/analgesic effects and its ulcerogenic actions. CT-3 warrants clinical development as a novel anti-inflammatory and analgesic drug.”

Full text: http://jpet.aspetjournals.org/content/291/1/31.long

Poly-ε-caprolactone microspheres as a drug delivery system for cannabinoid administration: development, characterization and in vitro evaluation of their antitumoral efficacy.

“Cannabinoids show promise for the treatment of various medical conditions such as emesis, anorexia, pain, cancer, multiple sclerosis, Parkinson’s disease and glaucoma.

The objective of the present work was to assess the feasibility of developing cannabinoid loaded poly-ε-caprolactone (PCL) microparticles prepared by the oil-in-water emulsion-solvent evaporation technique as a suitable dosage form for their administration.

In vitro cell viability studies demonstrated the antitumoral activity of CBD released from microparticles. After 4 and 7 days of incubation, CBD in microspheres significantly inhibited the growth of MDA-MB-231 cells by 60% as compared to the 50% attained with free drug.

The results suggest that PCL microparticles could be an alternative delivery system for long-term cannabinoid administration, showing potential therapeutic advantages over free drug.”

http://www.ncbi.nlm.nih.gov/pubmed/22580111

Preparation and characterization of Δ9-tetrahydrocannabinol-loaded biodegradable polymeric microparticles and their antitumoral efficacy on cancer cell lines.

“Cannabinoids present an interesting therapeutic potential as antiemetics, appetite stimulants in debilitating diseases (cancer, AIDS and multiple sclerosis), analgesics, and in the treatment of multiple sclerosis and cancer, among other conditions.

However, despite their high clinical potential, only few dosage forms are available to date. In this paper, the development of Δ9-tetrahydrocannabinol (THC) biodegradable microspheres as an alternative delivery system for cannabinoid parenteral administration is proposed. Tetrahydrocannabinol was encapsulated into biodegradable microspheres by the oil-in-water (o/w) emulsion solvent evaporation method. Several formulations were prepared using different drug:polymer ratios. The influence of antioxidant (α-tocopherol acetate) concentration on the release of THC from the microparticles was studied. Elevated process yield and entrapment efficiencies were achieved.The in vitro drug release studies showed that the encapsulated drug was released over a two week period.

 As THC has shown therapeutic potential as anticancer drug, the efficacy of the microspheres was tested on different cancer cell lines.

 Interestingly, the microspheres were able to inhibit cancer cell proliferation during the nine-day study period.

 All the above results suggest that the use of biodegradable microspheres would be a suitable alternative delivery system for THC administration.”

http://www.ncbi.nlm.nih.gov/pubmed/23773072

Acute Δ9-tetrahydrocannabinol blocks gastric hemorrhages induced by the nonsteroidal anti-inflammatory drug diclofenac sodium in mice.

“Nonsteroidal anti-inflammatory drugs (NSAIDs), which are among the most widely used analgesics in the world, cause gastrointestinal inflammation that is potentially life-threatening.

Although inhibitors of endocannabinoid catabolic enzymes protect against gastropathy in fasted NSAID-treated mice, the gastroprotective effects of Δ9-tetrahydrocannabinol (THC), the primary psychoactive component of marijuana, have yet to be investigated…

 These data indicate that the phytocannabinoid Δ9-THC protects against diclofenac-induced gastric inflammatory tissue damage at doses insufficient to cause common cannabinoid side effects.”

http://www.ncbi.nlm.nih.gov/pubmed/23769745

Turned-Off Cannabinoid Receptor Turns on Colorectal Tumor Growth – MDAnderson

“Researchers find CB1 suppresses tumors, a new potential path for treatment, prevention.”

 “New preclinical research shows that cannabinoid cell surface receptor CB1 plays a tumor-suppressing role in human colorectal cancer, scientists report in the Aug. 1 edition of the journal Cancer Research.

CB1 is well-established for relieving pain and nausea, elevating mood and stimulating appetite by serving as a docking station for the cannabinoid group of signaling molecules. It now may serve as a new path for cancer prevention or treatment.

“Potential application of cannabinoids as anti-tumor drugs is an exciting prospect, because cannabinoid agonists are being evaluated now to treat the side-effects of chemotherapy and radiation therapy,” DuBois said.

 “Turning CB1 back on and then treating with a cannabinoid agonist could provide a new approach to colorectal cancer treatment or prevention.”

Cannabinoids are a group of ligands that serve a variety of cell-signaling roles. Some are produced by the body internally (endocannabinoids). External cannabinoids include manmade versions and those present in plants, most famously the active ingredient in marijuana (THC).”

More:  http://www.mdanderson.org/newsroom/news-releases/2008/turned-off-cannabinoid-receptor-turns-on-colorectal-tumor-growth.html