The Antitumor Activity of Plant-Derived Non-Psychoactive Cannabinoids.

“As a therapeutic agent, most people are familiar with the palliative effects of the primary psychoactive constituent of Cannabis sativa (CS), Δ9-tetrahydrocannabinol (THC), a molecule active at both the cannabinoid 1 (CB1) and cannabinoid 2 (CB2) receptor subtypes.

Through the activation primarily of CB1 receptors in the central nervous system, THC can reduce nausea, emesis and pain in cancer patients undergoing chemotherapy.

During the last decade, however, several studies have now shown that CB1 and CB2 receptor agonists can act as direct antitumor agents in a variety of aggressive cancers.

In addition to THC, there are many other cannabinoids found in CS, and a majority produces little to no psychoactivity due to the inability to activate cannabinoid receptors.

For example, the second most abundant cannabinoid in CS is the non-psychoactive cannabidiol (CBD). Using animal models, CBD has been shown to inhibit the progression of many types of cancer including glioblastoma (GBM), breast, lung, prostate and colon cancer.

This review will center on mechanisms by which CBD, and other plant-derived cannabinoids inefficient at activating cannabinoid receptors, inhibit tumor cell viability, invasion, metastasis, angiogenesis, and the stem-like potential of cancer cells.

We will also discuss the ability of non-psychoactive cannabinoids to induce autophagy and apoptotic-mediated cancer cell death, and enhance the activity of first-line agents commonly used in cancer treatment.”

Cannabidiol stimulates Aml-1a-dependent glial differentiation and inhibits glioma stem-like cells proliferation by inducing autophagy in a TRPV2-dependent manner.

“Glioma stem-like cells (GSCs) correspond to a tumor cell subpopulation, involved in glioblastoma multiforme (GBM) tumor initiation and acquired chemoresistance. Currently, drug-induced differentiation is considered as a promising approach to eradicate this tumor-driving cell population.

Recently, the effect of cannabinoids (CBs) in promoting glial differentiation and inhibiting gliomagenesis has been evidenced. Herein, we demonstrated that cannabidiol (CBD) by activating Transient Receptor Potential Vanilloid-2 (TRPV2) triggers GSCs differentiation activating the autophagic process and inhibits GSCs proliferation and clonogenic capability.

Above all, CBD and carmustine (BCNU) in combination overcome the high resistance of GSCs to BCNU treatment, by inducing apoptotic cell death…

Altogether, these results support a novel mechanism by which CBD inducing TRPV2-dependent autophagic process stimulates Aml-1a-dependent GSCs differentiation, abrogating the BCNU chemoresistance in GSCs.”

http://www.ncbi.nlm.nih.gov/pubmed/25903924

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

Reactive oxygen species-mediated therapeutic response and resistance in glioblastoma.

“Glioblastoma (GBM) resistance to therapy is the most common cause of tumor recurrence, which is ultimately fatal in 90% of the patients 5 years after initial diagnosis. A sub-population of tumor cells with stem-like properties, glioma stem cells (GSCs), is specifically endowed to resist or adapt to the standard therapies, leading to therapeutic resistance.

Several anticancer agents, collectively termed redox therapeutics, act by increasing intracellular levels of reactive oxygen species (ROS).

In this study, we investigated mechanisms underlying GSC response and resistance to cannabidiol (CBD), a non-toxic, non-psychoactive cannabinoid and redox modulator.

…we demonstrated that combining CBD treatment with the inhibition of system Xc resulted in synergistic ROS increase leading to robust antitumor effects, that is, decreased GSC survival, self-renewal, and invasion.

Our investigation provides novel mechanistic insights into the antitumor activity of redox therapeutics and suggests that combinatorial approaches using small molecule modulators of ROS offer therapeutic benefits in GBM.”

http://www.ncbi.nlm.nih.gov/pubmed/25590811

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

 

 

The antitumor action of cannabinoids on glioma tumorigenesis.

“Cannabinoids are a class of chemical compounds with a wide spectrum of pharmacological effects, mediated by two specific plasma membrane receptors (CB1 and CB2).

Recently, CB1 and CB2 expression levels have been detected in human tumors, including those of brain.

Cannabinoids-endocannabinoids exert anti-inflammatory, anti-proliferative, anti-invasive, anti-metastatic and pro-apoptotic effects in different cancer types, both in vitro and in vivo in animal models, after local or systemic administration.

We present the available experimental and clinical data, to date, regarding the antitumor action of cannabinoids on the tumorigenesis of gliomas.”

http://www.ncbi.nlm.nih.gov/pubmed/25472761

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

The Combination of Cannabidiol and Δ9-Tetrahydrocannabinol Enhances the Anticancer Effects of Radiation in an Orthotopic Murine Glioma Model.

“High-grade glioma is one of the most aggressive cancers in adult humans and long-term survival rates are very low as standard treatments for glioma remain largely unsuccessful.

Cannabinoids have been shown to specifically inhibit glioma growth as well as neutralize oncogenic processes such as angiogenesis.

In an attempt to improve treatment outcome, we have investigated the effect of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) both alone and in combination with radiotherapy in a number of glioma cell lines (T98G, U87MG, and GL261).

Cannabinoids were used in two forms, pure (P) and as a botanical drug substance (BDS).

Results demonstrated a duration- and dose-dependent reduction in cell viability with each cannabinoid and suggested that THC-BDS was more efficacious than THC-P, whereas, conversely, CBD-P was more efficacious than CBD-BDS.

…increase in radiosensitivity was associated with an increase in markers of autophagy and apoptosis.

These in vitro results were recapitulated in an orthotopic murine model for glioma, which showed dramatic reductions in tumor volumes when both cannabinoids were used with irradiation.

Taken together, our data highlight the possibility that these cannabinoids can prime glioma cells to respond better to ionizing radiation, and suggest a potential clinical benefit for glioma patients by using these two treatment modalities.”

http://www.ncbi.nlm.nih.gov/pubmed/25398831

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

Distinctive pattern of cannabinoid receptor type II (CB2) expression in adult and pediatric brain tumors.

“The efficacy of cannabinoids against high-grade glioma in animal models, mediated by two specific receptors, CB1 and CB2, raised promises for targeted treatment of the most frequent and malignant primary brain tumors.

Unlike the abundantly expressed CB1, the CB2 receptor shows a restricted distribution in normal brain. Although brain tumors constitute the second most common malignancy in children and the prevalence of histological types of brain tumors vary significantly between the adult and pediatric populations, cannabinoid receptor expression in pediatric tumors remains unknown.

In the present study, we compared the expression of the CB2 receptor in paraffin-embedded sections from primary brain tumors of adult and pediatric patients. Most glioblastomas expressed very high levels of CB2 receptors and the expression correlated with tumor grade.

Interestingly, some benign pediatric astrocytic tumors, such as subependymal giant cell astrocytoma (SEGA), which may occasionally cause mortality owing to progressive growth, also displayed high CB2 immunoreactivity.

The high levels of CB2 expression would predestine those tumors to be vulnerable to cannabinoid treatment.

In contrast, all examined cases of embryonal tumors (medulloblastoma and S-PNET), the most frequently diagnosed malignant brain tumors in childhood, showed no or trace CB2 immunoreactivity.

Our results suggest that the CB2 receptor expression depends primarily on the histopathological origin of the brain tumor cells and differentiation state, reflecting the tumor grade.”

http://www.ncbi.nlm.nih.gov/pubmed/17239827

Endocannabinoid system in cancer cachexia.

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“More than 60% of advanced cancer patients suffer from anorexia and cachexia.

This review focuses on the possible mechanisms by which the endocannabinoid system antagonizes cachexia-anorexia processes in cancer patients and how it can be tapped for therapeutic applications.

Cannabinoids stimulate appetite and food intake…

Cannabinoid type 1 receptor activation stimulates appetite and promotes lipogenesis and energy storage.

Further study of cancer-cachexia pathophysiology and the role of endocannabinoids will help us to develop cannabinoids without psychotropic properties, which will help cancer patients suffering from cachexia and improve outcomes of clinical antitumor therapy.”

http://www.ncbi.nlm.nih.gov/pubmed/17563462

The endocannabinoid signaling system in cancer.

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“The endocannabinoid system, comprising lipid-derived endocannabinoids, their G-protein-coupled receptors (GPCRs), and the enzymes for their metabolism, is emerging as a promising therapeutic target in cancer.

This report highlights the main signaling pathways for the antitumor effects of the endocannabinoid system in cancer and its basic role in cancerpathogenesis, and discusses the alternative view of cannabinoid receptors as tumor promoters.

We focus on new players in the antitumor action of the endocannabinoid system and on emerging crosstalk among cannabinoid receptors and other membrane or nuclear receptors involved in cancer.”

http://www.ncbi.nlm.nih.gov/pubmed/23602129

Spontaneous regression of septum pellucidum/forniceal pilocytic astrocytomas–possible role of Cannabis inhalation.

“The purpose of this report is to document spontaneous regression of pilocytic astrocytomas of the septum pellucidum and to discuss the possible role of cannabis in promoting regression.

We report two children with septum pellucidum/forniceal pilocytic astrocytoma (PA) tumors… Neither patient received any conventional adjuvant treatment.

The tumors regressed over the same period of time that cannabis was consumed via inhalation, raising the possibility that the cannabis played a role in the tumor regression.”

http://www.ncbi.nlm.nih.gov/pubmed/21336992

Cannabinoid receptors in human astroglial tumors.

“…cannabinoids are reported to inhibit the growth of tumors, including gliomas. These effects have been claimed to be mediated via cannabinoid receptors 1 and 2 (CB1, CB2).

We conclude that cannabinoid therapy of human gliomas targets not only receptors on tumor, but also on other cell types…”

http://www.ncbi.nlm.nih.gov/pubmed/16893424