Systematic review of the literature on clinical and experimental trials on the antitumor effects of cannabinoids in gliomas.

“To evaluate, through a systematic review of the literature, the antitumoral effects of cannabinoids on gliomas…

  In all experimental studies included, cannabinoids exerted antitumoral activity in vitro and/or antitumoral evidence in vivo in several models of tumor cells and tumors.

The antitumor activity included: antiproliferative effects (cell cycle arrest), decreased viability and cell death by toxicity, apoptosis, necrosis, autophagy, as well as antiangiogenic and antimigratory effects.

 Antitumoral evidence included: reduction in tumor size, antiangiogenic, and antimetastatic effects.

 Additionally, most of the studies described that the canabinnoids exercised selective antitumoral action in several distinct tumor models. Thereby, normal cells used as controls were not affected.

The safety factor in the cannabinoids’ administration has also been demonstrated in vivo.

 The various cannabinoids tested in multiple tumor models showed antitumoral effects both in vitro and in vivo.

 These findings indicate that cannabinoids are promising compounds for the treatment of gliomas.”

http://www.ncbi.nlm.nih.gov/pubmed/24142199

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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

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Cannabinoids and gliomas.

Abstract

“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 non-transformed astroglial counterparts. On the basis of these preclinical findings, a pilot clinical study of Delta(9)-tetrahydrocannabinol (THC) in patients with recurrent glioblastoma multiforme has been recently run. The good safety profile of THC, together with its possible growth-inhibiting action on tumor cells, justifies the setting up of future trials aimed at evaluating the potential antitumoral activity of cannabinoids.”

http://www.ncbi.nlm.nih.gov/pubmed/17952650

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Cannabinoids Inhibit the Vascular Endothelial Growth Factor Pathway in Gliomas

“Cannabinoids, the active components of Cannabis sativa L. (marijuana), and their derivatives exert a wide array of effects by activating their specific G protein-coupled receptors CB1 and CB2, which are normally engaged by a family of endogenous ligands–the endocannabinoids. Marijuana and its derivatives have been used in medicine for many centuries, and there is currently a renaissance in the study of the therapeutic effects of cannabinoids. Today, cannabinoids are approved to palliate the wasting and emesis associated with cancer and AIDS chemotherapy, and ongoing clinical trials are determining whether cannabinoids are effective agents in the treatment of pain, neurodegenerative disorders such as multiple sclerosis, and traumatic brain injury . In addition, cannabinoid administration to mice and/or rats induces the regression of lung adenocarcinomas, gliomas, thyroid epitheliomas, lymphomas, and skin carcinomas. These studies have also evidenced that cannabinoids display a fair drug safety profile and do not produce the generalized cytotoxic effects of conventional chemotherapies, making them potential antitumoral agents.” 

“Gliomas are one of the most malignant forms of cancer, resulting in the death of affected patients within 1–2 two years after diagnosis. Current therapies for glioma treatment are usually ineffective or just palliative. Therefore, it is essential to develop new therapeutic strategies for the management of glioblastoma multiforme, which will most likely require a combination of therapies to obtain significant clinical results. In line with the idea that anti-VEGF treatments constitute one of the most promising antitumoral approaches currently available, the present laboratory and clinical findings provide a novel pharmacological target for cannabinoid-based therapies.”

“The use of cannabinoids in medicine is limited by their psychoactive effects mediated by neuronal CB1 receptors. Although these adverse effects are within the range of those accepted for other medications, especially in cancer treatment, and tend to disappear with tolerance on continuous use, it is obvious that cannabinoid-based therapies devoid of side-effects would be desirable. As glioma cells express functional CB2 receptors, we used a selective CB2 ligand to target the VEGF pathway. Selective CB2 receptor activation in mice also inhibits the growth and angiogenesis of skin carcinomas.”

“Cannabinoids inhibit tumor angiogenesis…”

“Cannabinoids Inhibit the Vascular Endothelial Growth Factor Pathway in Gliomas”

“Because blockade of the VEGF pathway constitutes one of the most promising antitumoral approaches currently available, the present findings provide a novel pharmacological target for cannabinoid-based therapies.”

http://cancerres.aacrjournals.org/content/64/16/5617.full

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