Cannabinoids – a new weapon against cancer?

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“Cannabis has been cultivated by man since Neolithic times. It was used, among others for fiber and rope production, recreational purposes and as an excellent therapeutic agent.

The isolation and characterization of the structure of one of the main active ingredients of cannabis – Δ9 – tetrahydrocannabinol as well the discovery of its cannabinoid binding receptors CB1 and CB2, has been a milestone in the study of the possibilities of the uses of Cannabis sativa and related products in modern medicine.

Many scientific studies indicate the potential use of cannabinoids in the fight against cancer.

Experiments carried out on cell lines in vitro and on animal models in vivo have shown that phytocannabinoids, endocannabinoids, synthetic cannabinoids and their analogues can lead to inhibition of the growth of many tumor types, exerting cytostatic and cytotoxic neoplastic effect on cells thereby negatively influencing neo-angiogenesis and the ability of cells to metastasize.

The main molecular mechanism leading to inhibition of proliferation of cancer cells by cannabinoids is apoptosis. Studies have shown, however, that the process of apoptosis in cells, treated with recannabinoids, is a consequence of induction of endoplasmic reticulum stress and autophagy. On the other hand, in the cellular context and dosage dependence, cannabinoids may enhance the proliferation of tumor cells by suppressing the immune system or by activating mitogenic factors.

Leading from this there is a an obvious need to further explore cannabinoid associated molecular pathways making it possible to develop safe therapeutic drug agents for patients in the future.”

Targeting Cutaneous Cannabinoid Signaling in Inflammation – A “High”-way to Heal?

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“The endocannabinoid system (ECS) is a recently emerging complex regulator of multiple physiological processes. It comprises several endogenous ligands (e.g. N-arachidonoylethanolamine, a.k.a. anandamide [AEA], 2-arachidonoylglycerol [2-AG], palmitoylethanolamide [PEA], etc.), a number of endocannabinoid (eCB)-responsive receptors (e.g. CB1 and CB2, etc.), as well as enzymes and transporters involved in the synthesis and degradation of the eCBs.

Among many other tissues and organs, various members of the ECS were shown to be expressed in the skin as well. Indeed, AEA, 2-AG, CB1 and CB2 together with the major eCB-metabolizing enzymes (e.g. fatty acid amide hydrolase [FAAH], which cleaves AEA to ethanolamine and pro-inflammatory arachidonic acid) were found in various cutaneous cell types. Importantly, the eCB-tone and cannabinoid signaling in general appear to play a key role in regulating several fundamental aspects of cutaneous homeostasis, including proliferation and differentiation of epidermal keratinocytes, hair growth, sebaceous lipid production, melanogenesis, fibroblast activity, etc.

Moreover, appropriate eCB-signaling through CB1 and CB2 receptors was found to be crucially important in keeping cutaneous inflammatory processes under control.

Collectively, these findings (together with many other recently published data) implied keratinocytes to be “non-classical” immune competent cells, playing a central role in initiation and regulation of cutaneous immune processes, and the “c(ut)annabinoid” system is now proven to be one of their master regulators.

Another recently emerging, fascinating possibility to manage cutaneous inflammation through the cannabinoid signaling is the administration of phytocannabinoids (pCB). Cannabis sativa contains over 100 different pCBs, the vast majority of which have no psychotropic activity, and usually possess a “favorable” side-effect profile, which makes these substances particularly interesting drug candidates in treating several inflammation-accompanied diseases.

With respect to the skin, we have recently shown that one of the best studied pCBs, (−)-cannabidiol (CBD), may have great potential in managing acne, an inflammation-accompanied, extremely prevalent cutaneous disease.

Collectively, in light of the above results, both increase/restoration of the homeostatic cutaneous eCB-tone by FAAH-inhibitors and topical administration of non-psychotropic pCBs hold out the promise to exert remarkable anti-inflammatory actions, making them very exciting drug candidates, deserving full clinical exploration as potent, yet safe novel class of anti-inflammatory agents.”

http://www.ebiomedicine.com/article/S2352-3964(17)30003-8/fulltext

Manipulation of the Endocannabinoid System in Colitis: A Comprehensive Review.

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“Inflammatory bowel disease (IBD) is a lifelong disease of the gastrointestinal tract whose annual incidence and prevalence is on the rise. Current immunosuppressive therapies available for treatment of IBD offer limited benefits and lose effectiveness, exposing a significant need for the development of novel therapies. In the clinical setting, cannabis has been shown to provide patients with IBD symptomatic relief, although the underlying mechanisms of their anti-inflammatory effects remain unclear.

RESULTS:

Cannabinoid receptors 1 and 2, endogenous cannabinoids, and atypical cannabinoids are upregulated in inflammation, and their presence and stimulation attenuate murine colitis, whereas cannabinoid receptor antagonism and cannabinoid receptor deficient models reverse these anti-inflammatory effects. In addition, inhibition of endocannabinoid degradation through monoacylglycerol lipase and fatty acid amide hydrolase blockade can also attenuate colitis development, and is closely linked to cannabinoid receptor expression.

CONCLUSIONS:

Although manipulation of the endocannabinoid system in murine colitis has proven to be largely beneficial in attenuating inflammation, there is a paucity of human study data. Further research is essential to clearly elucidate the specific mechanisms driving this anti-inflammatory effect for the development of therapeutics to target inflammatory disease such as IBD.”

https://www.ncbi.nlm.nih.gov/pubmed/28079617

“Plant cannabinoids THC and CBD proved beneficial in DNBS-induced colitis in a bell-shaped dose-related response, but more importantly, the effects of the phytocannabinoids were additive, as CBD increased an ineffective THC dose to the level of an effective one.” https://academic.oup.com/ibdjournal/article/23/2/192/4347176

Cannabinol and cannabidiol exert opposing effects on rat feeding patterns.

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“Increased food consumption following ∆(9)-tetrahydrocannabinol-induced cannabinoid type 1 receptor agonism is well documented.

However, possible non-∆(9)-tetrahydrocannabinol phytocannabinoid-induced feeding effects have yet to be fully investigated. Therefore, we have assessed the effects of the individual phytocannabinoids, cannabigerol, cannabidiol and cannabinol, upon feeding behaviors.

Cannabinol induced a CB(1)R-mediated increase in appetitive behaviors via significant reductions in the latency to feed and increases in consummatory behaviors via increases in meal 1 size and duration. Cannabinol also significantly increased the intake during hour 1 and total chow consumed during the test. Conversely, cannabidiol significantly reduced total chow consumption over the test period. Cannabigerol administration induced no changes to feeding behavior.

This is the first time cannabinol has been shown to increase feeding. Therefore, cannabinol could, in the future, provide an alternative to the currently used and psychotropic ∆(9)-tetrahydrocannabinol-based medicines since cannabinol is currently considered to be non-psychotropic.

Furthermore, cannabidiol reduced food intake in line with some existing reports, supporting the need for further mechanistic and behavioral work examining possible anti-obesity effects of cannabidiol.”

https://www.ncbi.nlm.nih.gov/pubmed/22543671

Cannabis sativa and the endogenous cannabinoid system: therapeutic potential for appetite regulation.

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“The herb Cannabis sativa (C. sativa) has been used in China and on the Indian subcontinent for thousands of years as a medicine.

However, since it was brought to the UK and then the rest of the western world in the late 19th century, its use has been a source of controversy. Indeed, its psychotropic side effects are well reported but only relatively recently has scientific endeavour begun to find valuable uses for either the whole plant or its individual components.

Here, we discuss evidence describing the endocannabinoid system, its endogenous and exogenous ligands and their varied effects on feeding cycles and meal patterns.

Furthermore we also critically consider the mounting evidence which suggests non-Δ(9) tetrahydrocannabinol phytocannabinoids play a vital role in C. sativa-induced feeding pattern changes.

Indeed, given the wide range of phytocannabinoids present in C. sativa and their equally wide range of intra-, inter- and extra-cellular mechanisms of action, we demonstrate that non-Δ(9) tetrahydrocannabinol phytocannabinoids retain an important and, as yet, untapped clinical potential.”

https://www.ncbi.nlm.nih.gov/pubmed/21213357

Non-Δ⁹tetrahydrocannabinol phytocannabinoids stimulate feeding in rats.

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“Cannabinoid type 1 receptor-mediated appetite stimulation by Δ⁹tetrahydrocannabinol (Δ⁹THC) is well understood.

Recently, it has become apparent that non-Δ⁹THC phytocannabinoids could also alter feeding patterns.

Here, we show definitively that non-Δ⁹THC phytocannabinoids stimulate feeding.

Twelve male, Lister-Hooded rats were prefed to satiety prior to administration of a standardized cannabis extract or to either of two mixtures of pure phytocannabinoids (extract analogues) comprising the phytocannabinoids present in the same proportions as the standardized extract (one with and one without Δ⁹THC). Hourly intake and meal pattern data were recorded and analysed using two-way analysis of variance followed by one-way analysis of variance and Bonferroni post-hoc tests.

Administration of both extract analogues significantly increased feeding behaviours over the period of the test. All three agents increased hour-one intake and meal-one size and decreased the latency to feed, although the zero-Δ⁹THC extract analogue did so to a lesser degree than the high-Δ⁹THC analogue.

Furthermore, only the analogue containing Δ⁹THC significantly increased meal duration.

The data confirm that at least one non-Δ⁹THC phytocannabinoid induces feeding pattern changes in rats, although further trials using individual phytocannabinoids are required to fully understand the observed effects.”

https://www.ncbi.nlm.nih.gov/pubmed/22157176

A low-Δ9 tetrahydrocannabinol cannabis extract induces hyperphagia in rats.

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“Appetite stimulation via partial agonism of cannabinoid type 1 receptors by Δtetrahydrocannabinol (ΔTHC) is well documented and can be modulated by non-ΔTHC phytocannabinoids.

ΔTHC concentrations sufficient to elicit hyperphagia induce changes to both appetitive (reduced latency to feed) and consummatory (increased meal one size and duration) behaviours.

Here, we show that a cannabis extract containing too little ΔTHC to stimulate appetite can induce hyperphagia solely by increasing appetitive behaviours.

These results show only the increase in appetitive behaviours, which could be attributed to non-ΔTHC phytocannabinoids in the extract rather than ΔTHC.

Although further study is required to determine the constituents responsible for these effects, these results support the presence of non-ΔTHC cannabis constituent(s) that exert a stimulatory effect on appetite and likely lack the detrimental psychoactive effects of ΔTHC.”

https://www.ncbi.nlm.nih.gov/pubmed/20975531

Cannabis and epilepsy: An ancient treatment returns to the fore.

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“Cannabis has been associated with the treatment of epilepsy throughout history, and if ancient Assyrian sources referring to “hand of ghost” are considered credible, this relationship may span four millennia.

A tradition of usage continued in Arabic medicine and Ayurvedic practice in India, which led, in turn, to early experiments in Europe and North America with “Indian hemp.”

Lack of standardization, bioavailability issues, and ultimately prohibition were all factors in cannabis-based medicines failing to maintain mainstream usage in seizure treatment, but investigation was resumed in the 1970s with interesting signals noted in both laboratory and clinical settings.

Early case studies showed promise, but lacked sufficient rigor. Resumption of research coupled with mass experimentation by families of epilepsy patients has led to intense interest in cannabis-based medicines for its treatment once more, with greatest focus on cannabidiol, but additional investigation of tetrahydrocannabinol, tetrahydrocannabinolic acid, and other phytocannabinoids.”

https://www.ncbi.nlm.nih.gov/pubmed/27989385

Inhibition of cervical cancer cell proliferation by cannabidiol

“Seventy phytocannabinoids are now known to be synthesized by Cannabis sativa (marijuana)]. The major non-psychoactive cannabinoid cannabidiol (CBD) exhibits antiproliferative effects against breast, cervix, colon, glioma, leukemia, ovary, prostate, and thyroid cancer cells. In this study, we investigated the antiproliferative effect of CBD on the ME-180 cervical cancer cell line. The results of our study suggest that CBD exerts its antiproliferative effect via multiple mechanisms, and it could be a potential treatment for cervical cancer.”

https://www.thieme-connect.com/DOI/DOI?10.1055/s-0036-1596862

Cannabidiol Regulation of Learned Fear: Implications for Treating Anxiety-Related Disorders.

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“Anxiety and trauma-related disorders are psychiatric diseases with a lifetime prevalence of up to 25%. Phobias and post-traumatic stress disorder (PTSD) are characterized by abnormal and persistent memories of fear-related contexts and cues. The effects of psychological treatments such as exposure therapy are often only temporary and medications can be ineffective and have adverse side effects.

Growing evidence from human and animal studies indicates that cannabidiol, the main non-psychotomimetic phytocannabinoid present in Cannabis sativa, alleviates anxiety in paradigms assessing innate fear.

More recently, the effects of cannabidiol on learned fear have been investigated in preclinical studies with translational relevance for phobias and PTSD.

Here we review the findings from these studies, with an emphasis on cannabidiol regulation of contextual fear.

The evidence indicates that cannabidiol reduces learned fear in different ways: (1) cannabidiol decreases fear expression acutely, (2) cannabidiol disrupts memory reconsolidation, leading to sustained fear attenuation upon memory retrieval, and (3) cannabidiol enhances extinction, the psychological process by which exposure therapy inhibits learned fear.

We also present novel data on cannabidiol regulation of learned fear related to explicit cues, which indicates that auditory fear expression is also reduced acutely by cannabidiol.

We conclude by outlining future directions for research to elucidate the neural circuit, psychological, cellular, and molecular mechanisms underlying the regulation of fear memory processing by cannabidiol.

This line of investigation may lead to the development of cannabidiol as a novel therapeutic approach for treating anxiety and trauma-related disorders such as phobias and PTSD in the future.”