Preclinical evidence on the anticancer properties of phytocannabinoids

Image result for CROSBI“Phytocannabinoids are unique terpenophenolic compounds predominantly produced in the glandular trichomes of the cannabis plant (Cannabis sativa L.). The delta-9- tetrahydrocannabinol (THC) is the main active constituent responsible for the plant’s psychoactive effect and, together with the non- psychoactive cannabidiol (CBD), the most investigated naturally occurring cannabinoid.

The first report on the antitumor properties of cannabis compounds appeared more than forty years ago, but the potential of targeting the endocannabinoid system in cancer has recently attracted increasing interest. Our study aimed to review the last decade’s findings on the anticancer potential of plant- derived cannabinoids and the possible mechanisms of their activity.

A large body of in vitro data has been accumulated demonstrating that phytocannabinoids affect a wide spectrum of tumor cells, including gliomas, neuroblastomas, hepatocarcinoma as well as skin, prostate, breast, cervical, colon, pancreatic, lung and hematological cancer.

It has been found that they can stop the uncontrolled growth of cancer cells through the cell-cycle arrest, inhibition of cell proliferation and induction of autophagy and apoptosis. They can also block all the steps of tumor progression, including tumor cell migration, adhesion and invasion as well as angiogenesis. The observed effects are mainly mediated by the cannabinoid CB1 and/or CB2 receptors, although some other receptors and mechanisms unrelated to receptor stimulation may also be involved.

The majority of available animal studies confirmed that phytocannabinoids are capable of effectively decreasing cancer growth and metastasis in vivo. THC was found to be effective against experimental glioma, liver, pancreatic, breast and lung cancer while CBD showed activity against glioma and neuroblastoma, melanoma, colon, breast, prostate and lung cancer. Further in vitro and in vivo studies also greatly support their use in combination with traditional chemotherapy or radiotherapy, which results in improved efficiency, attenuated toxicity or reduced drug resistance.

Taken together most of available preclinical results emphasize the extensive therapeutic potential of THC and CBD in various types of cancers. The potential clinical interest of cannabinoids is additionally suggested by their selectivity for tumor cells as well as their good tolerance and the absence of normal tissue toxicity, which are still the major limitations of most conventional drugs. The accumulated preclinical evidence strongly suggests the need for clinical testing of cannabinoids in cancer patients.”

The therapeutic role of cannabinoid receptors and its agonists or antagonists in Parkinson’s disease.

Progress in Neuro-Psychopharmacology and Biological Psychiatry“Parkinson’s disease (PD) is a neurodegenerative disease and its characteristic is the progressive degeneration of dopaminergic neurons within the substantia nigra (SN) of the midbrain. There is hardly any clinically proven efficient therapeutics for its cure in several recent preclinical advances proposed to treat PD.

Recent studies have found that the endocannabinoid signaling system in particular the comprised two receptors, CB1 and CB2 receptors, has a significant regulatory function in basal ganglia and is involved in the pathogenesis of PD. Therefore, adding new insights into the biochemical interactions between cannabinoids and other signaling pathways may help develop new pharmacological strategies.

Factors of the endocannabinoid system (ECS) are abundantly expressed in the neural circuits of basal ganglia, where they interact interactively with glutamatergic, γ-aminobutyric acid-ergic (GABAergic), and dopaminergic signaling systems. Although preclinical studies on PD are promising, the use of cannabinoids at the clinical level has not been thoroughly studied.

In this review, we evaluated the available evidence and reviewed the involvement of ECS in etiologies, symptoms and treatments related to PD. Since CB1 and CB2 receptors are the two main receptors of endocannabinoids, we primarily put the focus on the therapeutic role of CB1 and CB2 receptors in PD. We will try to determine future research clues that will help understand the potential therapeutic benefits of the ECS in the treatment of PD, aiming to open up new strategies and ideas for the treatment of PD.”

https://www.ncbi.nlm.nih.gov/pubmed/31442553

https://www.sciencedirect.com/science/article/pii/S0278584619302210?via%3Dihub

Cannabidiol and the Remainder of the Plant Extract Modulate the Effects of Δ9-Tetrahydrocannabinol on Fear Memory Reconsolidation.

Image result for frontiers in behavioral neuroscience “Δ9-Tetrahydrocannabinol (THC, a CB1 receptor agonist) and Cannabidiol (CBD, a non-competitive antagonist of endogenous CB1 and CB2 ligands) are two primary components of Cannabis species, and may modulate fear learning in mammals.

The CB1 receptor is widely distributed throughout the cortex and some limbic regions typically associated with fear learning. Humans with posttraumatic disorder (PTSD) have widespread upregulation of CB1 receptor density and reduced availability of endogenous cannabinoid anandamide, suggesting a role for the endocannabinoid system in PTSD.

Pharmacological blockade of memory reconsolidation following recall of a conditioned response modulates the expression of learned fear and may represent a viable target for the development of new treatments for PTSD.

In this study, we focused on assessing the impact of the key compounds of the marijuana plant both singly and, more importantly, in concert on attenuation of learned fear. Specifically, we assessed the impact of THC, CBD, and/or the remaining plant materials (post-extraction; background material), on reconsolidation of learned fear.

Results: CBD alone, but not THC alone, significantly attenuated fear memory reconsolidation when administered immediately after recall. The effect persisted for at least 7 days. A combination of CBD and THC also attenuated the fear response. Plant BM also significantly attenuated reconsolidation of learned fear both on its own and in combination with THC and CBD. Finally, THC attenuated reconsolidation of learned fear only when co-administered with CBD or plant BM.

Conclusion: CBD may provide a novel treatment strategy for targeting fear-memories. Furthermore, plant BM also significantly attenuated the fear response. However, whereas THC alone had no significant effects, its effects were modulated by the addition of other compounds. Future research should investigate some of the other components present in the plant BM (such as terpenes) for their effects alone, or in combination with isolated pure cannabinoids, on fear learning.”

https://www.ncbi.nlm.nih.gov/pubmed/31417379

https://www.frontiersin.org/articles/10.3389/fnbeh.2019.00174/full

New approaches to cancer therapy: combining Fatty Acid Amide Hydrolase (FAAH) inhibition with Peroxisome Proliferator-Activated Receptors (PPARs) activation.

 Go to Volume 0, Issue ja“Over the course of the last decade, Peroxisome Proliferator-Activated Receptors (PPARs) have been identified as part of the cannabinoid signaling system: both phytocannabinoids and endocannabinoids are capable of binding and activating these nuclear receptors. Fatty Acid Amide Hydrolase (FAAH) hydrolyzes the endocannabinoid Anandamide and other N-Acylethanolamines. These substances have been shown to have numerous anti-cancer effects, and indeed the inhibition of FAAH has multiple beneficial effects that are mediated by PPARα subtype and by PPARγ subtype, especially antiproliferation and activation of apoptosis. The substrates of FAAH are also PPAR agonists, which explains the PPAR-mediated effects of FAAH inhibitors. Much like cannabinoid ligands and FAAH inhibitors, PPARγ agonists show antiproliferative effects on cancer cells, suggesting that additive or synergistic effects may be achieved through the positive modulation of both signaling systems. In this perspective, we discuss the development of novel FAAH inhibitors able to directly act as PPAR agonists and their promising utilization as leads for the discovery of highly effective anti-cancer compounds.”

https://www.ncbi.nlm.nih.gov/pubmed/31407888

https://pubs.acs.org/doi/10.1021/acs.jmedchem.9b00885

The Acute Activation of the CB1 Receptor in the Hippocampus Decreases Neurotoxicity and Prevents Spatial Memory Impairment in Rats Lesioned with β-Amyloid 25-35.

Neuroscience“Given their anti-inflammatory properties, cannabinoids have been shown to be neuroprotective agents and to reduce excitotoxicity, through the activation of the Cannabinoid receptor type 1 (CB1r).

These properties have led to CB1r being proposed as pharmacological targets for the treatment of various neurodegenerative diseases.

This study aimed to evaluate the neuroprotective effect of an acute activation of CB1r on spatial memory and its impact on iNOS protein expression, NO● levels, gliosis and the neurodegenerative process induced by the injection of Aβ(25-35) into the CA1 subfield of the hippocampus.

The data obtained in the present research suggest that the acute early activation of CB1r is crucial for neuroprotection.”

https://www.ncbi.nlm.nih.gov/pubmed/31400487

https://www.sciencedirect.com/science/article/abs/pii/S0306452219305433?via%3Dihub

Bones and Joints: The Effects of Cannabinoids on the Skeleton.

Image result for j clin endocrinol metab“This paper reviews the endocannabinoid system and focuses on the role of endocannabinoids in bone metabolism and their potential use in the management of conditions associated with bone loss.

CONTEXT:

The endocannabinoid system uses tissue-specific lipid ligands and G protein-coupled transmembrane receptors to regulate neurological, metabolic, and immune responses. Recent studies demonstrate that the endocannabinoid system influences bone metabolism. With the increasing use of endocannabinoid mimetics, e.g. tetrahydrocannabinol (THC) and cannabidiol (CBD), endocannabinoids’ involvement in bone growth and remodeling has become clinically relevant.

EVIDENCE ACQUISITION:

This literature review is based upon a search of Pubmed and Google Scholar databases, as of June 2019, for all English-language publications relating to cannabinoids and bone. We evaluated retrieved articles for relevance, experimental design, data acquisition, statistical analysis, and conclusions.

EVIDENCE SYNTHESIS:

Preclinical studies establish a role for endocannabinoids in bone metabolism. These studies yield complex and often contradictory results attributed to differences in the specific experimental model examined. Studies using human cells or subjects are limited.

CONCLUSIONS:

In vitro and animal models document that endocannabinoids participate in bone biology. The relevance of these observations to humans is not clear. The increasing chronic use of medical and recreational cannabis underscores the need to better understand the role of endocannabinoids in human bone metabolism. Moreover, it is important to evaluate the role of endocannabinoids as a therapeutic target to prevent and treat disorders associated with bone loss.”

https://www.ncbi.nlm.nih.gov/pubmed/31393556

“[The endocannabinoid system and bone].”  https://www.ncbi.nlm.nih.gov/pubmed/27734700

“Joint problems arising from lack of repair mechanisms: can cannabinoids help?”  https://www.ncbi.nlm.nih.gov/pubmed/29574720

“Cannabinoids and bone regeneration.”  https://www.ncbi.nlm.nih.gov/pubmed/30702341

“Cannabinoids and the skeleton: from marijuana to reversal of bone loss.”  https://www.ncbi.nlm.nih.gov/pubmed/19634029

Cannabinoid receptor-1 antagonism: a new perspective on treating a murine schistosomal liver fibrosis model.

 SciELO - Scientific Electronic Library Online“Formation of schistosomal granulomata surrounding the ova can result in schistosomiasis-associated liver fibrosis (SSLF). The current standard of treatment is praziquantel (PZQ), which cannot effectively reverse SSLF.

The role of the cannabinoid (CB) receptor family in liver fibrosis has recently been highlighted.

This study aimed to assess the therapeutic effect of CB1 receptor antagonism in reversing SSLF in a murine model of Schistosoma mansoni infection.

MAIN CONCLUSIONS:

Combining PZQ with CB1 receptor antagonists yielded the best results in reversing SSLF. To our knowledge, this is the first study to test this regimen in S. mansoni infection.”

https://www.ncbi.nlm.nih.gov/pubmed/31389521

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0074-02762019000100338&tlng=en

Endocannabinoid System and Alcohol Abuse Disorders.

“Δ9-tetrahydrocannabinol (Δ9-THC), the primary active component in Cannabis sativa preparations such as hashish and marijuana, signals by binding to cell surface receptors. Two types of receptors have been cloned and characterized as cannabinoid (CB) receptors. CB1 receptors (CB1R) are ubiquitously present in the central nervous system (CNS) and are present in both inhibitory interneurons and excitatory neurons at the presynaptic terminal. CB2 receptors (CB2R) are demonstrated in microglial cells, astrocytes, and several neuron subpopulations and are present in both pre- and postsynaptic terminals.

The majority of studies on these receptors have been conducted in the past two and half decades after the identification of the molecular constituents of the endocannabinoid (eCB) system that started with the characterization of CB1R. Subsequently, the seminal discovery was made, which suggested that alcohol (ethanol) alters the eCB system, thus establishing the contribution of the eCB system in the motivation to consume ethanol. Several preclinical studies have provided evidence that CB1R significantly contributes to the motivational and reinforcing properties of ethanol and that the chronic consumption of ethanol alters eCB transmitters and CB1R expression in the brain nuclei associated with addiction pathways.

Additionally, recent seminal studies have further established the role of the eCB system in the development of ethanol-induced developmental disorders, such as fetal alcohol spectrum disorders (FASD). These results are augmented by in vitro and ex vivo studies, showing that acute and chronic treatment with ethanol produces physiologically relevant alterations in the function of the eCB system during development and in the adult stage. This chapter provides a current and comprehensive review of the literature concerning the role of the eCB system in alcohol abuse disorders (AUD).”

https://www.ncbi.nlm.nih.gov/pubmed/31332736

https://link.springer.com/chapter/10.1007%2F978-3-030-21737-2_6

“Binge Alcohol Exposure Transiently Changes the Endocannabinoid System: A Potential Target to Prevent Alcohol-Induced Neurodegeneration.”  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5742761/

Endogenous cannabinoid levels and suicidality in combat veterans.

Psychiatry Research“Combat veterans are at elevated suicide risk. The goal of this study was to test the hypothesis that combat veterans who have made a suicide attempt post-deployment can be distinguished from combat veterans who have never made a suicide attempt based on differences in psychological and biological variables. For the latter, we focused on endogenous cannabinoids, neuroendocrine markers that are associated with stress. Demographic and clinical parameters of suicide attempters and non-attempters were assessed. Blood samples were assayed for anandamide (AEA), 2-arachidonoylglycerol (2-AG), and cortisol. Suicide attempters had higher Scale for Suicidal Ideation (SSI) scores in comparison to non-attempters. Controlling for gender, 2-AG levels were higher among suicide attempters in comparison to non-attempters. Cortisol levels positively correlated with 2-AG levels and negatively correlated with SSI scores among non-attempters but not among attempters. AEA levels negatively correlated with SSI scores among attempters but not among non-attempters. Our results indicate that there are psychological and biological differences between combat veterans with or without a history of suicidal attempt. Our findings also suggest that clinically observed differences between the groups may have a neurobiological basis.”

https://www.ncbi.nlm.nih.gov/pubmed/31375282

https://www.sciencedirect.com/science/article/abs/pii/S0165178119315173?via%3Dihub

“Role of the Endocannabinoid System in the Neurobiology of Suicide”  https://www.ncbi.nlm.nih.gov/books/NBK107200/

Endocannabinoid Signaling in the Central Amygdala and Bed Nucleus of the Stria Terminalis: Implications for the Pathophysiology and Treatment of Alcohol Use Disorder.

Alcoholism: Clinical and Experimental Research banner“High rates of relapse are a chronic and debilitating obstacle to effective treatment of alcohol use disorder (AUD); however, no effective treatments are available to treat symptoms induced by protracted abstinence.

In the first part of this two-part review series, we examine the literature supporting the effects of alcohol exposure within the extended amygdala (EA) neural circuitry.

In part two, we focus in on a potential way to combat negative affect associated with AUD, by exploring the therapeutic potential of the endogenous cannabinoid (eCB) system.

The eCB system is a potent modulator of neural activity in the brain, and its ability to mitigate stress and negative affect has long been an area of interest for developing novel therapeutics.

This review details the recent advances in our understanding of eCB signaling in two key regions of the EA, the central nucleus of the amygdala (CeA) and the bed nucleus of the stria terminalis (BNST), and their role in regulating negative affect.

Despite an established role for EA eCB signaling in reducing negative affect, few studies have examined the potential for eCB-based therapies to treat AUD-associated negative affect.

In this review, we present an overview of studies focusing on eCB signaling in EA and cannabinoid modulation on EA synaptic activity. We further discuss studies suggesting dysregulation of eCB signaling in models of AUD and propose that pharmacological augmentation of eCB could be a novel approach to treat aspects of AUD.

Lastly, future directions are proposed to advance our understanding of the relationship between AUD-associated negative affect and the EA eCB system that could yield new pharmacotherapies targeting negative affective symptoms associated with AUD.”

https://www.ncbi.nlm.nih.gov/pubmed/31373708

https://onlinelibrary.wiley.com/doi/abs/10.1111/acer.14159