The Therapeutic Aspects of the Endocannabinoid System (ECS) for Cancer and their Development: From Nature to Laboratory

Clinical Importance of Cannabinoid Type 1 Receptor (CB1R) and Cannabinoid Type 2 Receptor (CB2R) Expression in Renal Cell Carcinoma

Background and objective The purpose of our study was to assess the expression of cannabinoid type 1 receptor (CB1R) and cannabinoid type 2 receptor (CB2R), including positivity, intensity, percentage, site of distribution, and immunohistochemical score, in renal cell carcinomas (RCCs) and explore their correlation with various clinicopathological aspects. Methodology We retrospectively obtained data and specimens from 87 patients diagnosed with RCC after partial or radical nephrectomy, and the CB1R and CB2R expression was assessed immunohistochemically on paraffin-embedded tissues. The results were statistically analyzed uni- and multi-factorial along with clinicopathological parameters. Results CB1R was not expressed at all, and CB2R was highly expressed in 78 (89.7%) patients with RCC. In unifactorial analysis, no statistical significance was found in any of the analyzed parameters. However, in the multifactorial analysis, we found that patients with a papillary histologic type (P < 0.0005) were associated with a lower likelihood of expression of the CB2R in the membranous compared with those with clear-cell and were also associated with a higher likelihood of moderate or strong expression of CB2R immunohistochemical score compared with those with clear-cell (P = 0.03). Patients with stage T2 (P = 0.010) had more enhanced expression (grade 3 CB2R intensity) compared with those with stage T1. Males (beta coefficient ± standard error [SE] 13.70 ± 7.04; P = 0.056) and patients with chromophobe histologic type (beta coefficient ± SE 23.45 ± 9.86; P = 0.020) were associated with a higher percentage of CB2R expression. Conclusions Our data suggest that although the CB1R was not expressed in RCCs, CB2R was expressed in almost every patient and enhanced expression was noted in correlation with specific clinicopathological aspects of the patients. Thus, following well-designed studies, especially CB2R could be used as a prognostic marker or even as a potential therapeutic target in RCC.

Targeting the Endocannabinoid System Present in the Glioblastoma Tumour Microenvironment as a Potential Anti-Cancer Strategy

The highly aggressive and invasive glioblastoma (GBM) tumour is the most malignant lesion among adult-type diffuse gliomas, representing the most common primary brain tumour in the neuro-oncology practice of adults. With a poor overall prognosis and strong resistance to treatment, this nervous system tumour requires new innovative treatment. GBM is a polymorphic tumour consisting of an array of stromal cells and various malignant cells contributing to tumour initiation, progression, and treatment response. Cannabinoids possess anti-cancer potencies against glioma cell lines and in animal models. To improve existing treatment, cannabinoids as functionalised ligands on nanocarriers were investigated as potential anti-cancer agents. The GBM tumour microenvironment is a multifaceted system consisting of resident or recruited immune cells, extracellular matrix components, tissue-resident cells, and soluble factors. The immune microenvironment accounts for a substantial volume of GBM tumours. The barriers to the treatment of glioblastoma with cannabinoids, such as crossing the blood-brain barrier and psychoactive and off-target side effects, can be alleviated with the use of nanocarrier drug delivery systems and functionalised ligands for improved specificity and targeting of pharmacological receptors and anti-cancer signalling pathways. This review has shown the presence of endocannabinoid receptors in the tumour microenvironment, which can be used as a potential unique target for specific drug delivery. Existing cannabinoid agents, studied previously, show anti-cancer potencies via signalling pathways associated with the hallmarks of cancer. The results of the review can be used to provide guidance in the design of future drug therapy for glioblastoma tumours.

In Vitro and In Vivo Anti-Inflammatory Effects of Cannabidiol Isolated from Novel Hemp (Cannabis sativa L.) Cultivar Pink Pepper

Cannabis sativa L. contains more than 80 cannabinoids, among which cannabidiol (CBD) is the main neuroactive component. We aimed to investigate the anti-inflammatory efficacy of CBD in vitro and in vivo isolated from "Pink pepper", a novel hemp cultivar, by repeating the method of selecting and cultivating individuals with the highest CBD content. We investigated the effects of CBD on inflammatory markers elevated by lipopolysaccharide (LPS) treatment in RAW 264.7 mouse macrophage cells through Western blot and RT-PCR. In addition, we confirmed these effects through the ELISA of inflamed paw tissue of a λ-carrageenan-induced mouse edema model that received an oral administration of CBD. CBD inhibited the LPS-induced phosphorylation of NF-κB and MAPK in RAW 264.7 and exhibited anti-inflammatory effects by participating in these pathways. In our in vivo study, we confirmed that CBD also inhibited the inflammatory mediators of proteins extracted from edematous mouse paw tissue. These results show that CBD isolated from "Pink pepper" exhibits potent anti-inflammatory effects. These anti-inflammatory effects of CBD have pharmacological and physiological significance, highlighting the industrial value of this novel cultivar.

Rational Design, Synthesis, and Evaluation of Fluorescent CB2 Receptor Ligands for Live-Cell Imaging: A Comprehensive Review

The cannabinoid receptors CB1 and CB2 are class A G protein-coupled receptors (GPCRs) that are activated via endogenous lipids called endocannabinoids. The endocannabinoid system (ECS) plays a critical role in the regulation of several physiological states and a wide range of diseases. In recent years, drug discovery approaches targeting the cannabinoid type 2 receptor (CB2R) have gained prominence. Particular attention has been given to selective agonists targeting the CB2 receptors to circumvent the neuropsychotropic side effects associated with CB1 receptors. The pharmacological modulation of CB2R holds therapeutic promise for various diseases, such as inflammatory disorders and immunological conditions, as well as pain management and cancer treatment. Recently, the utilization of fluorescent probes has emerged as a valuable technique for investigating the interactions between ligands and proteins at an exceptional level of spatial and temporal precision. In this review, we aim to examine the progress made in the development of fluorescent probes targeting CB2 receptors and highlight their significance in facilitating the successful clinical translation of CB2R-based therapies.

Motifs in Natural Products as Useful Scaffolds to Obtain Novel Benzo[d]imidazole-Based Cannabinoid Type 2 (CB2) Receptor Agonists

The endocannabinoid system (ECS) constitutes a broad-spectrum modulator of homeostasis in mammals, providing therapeutic opportunities for several pathologies. Its two main receptors, cannabinoid type 1 (CB1) and type 2 (CB2) receptors, mediate anti-inflammatory responses; however, their differing patterns of expression make the development of CB2-selective ligands therapeutically more attractive. The benzo[d]imidazole ring is considered to be a privileged scaffold in drug discovery and has demonstrated its versatility in the development of molecules with varied pharmacologic properties. On the other hand, the main psychoactive component of Cannabis sativa, delta-9-tetrahydrocannabinol (THC), can be structurally described as an aliphatic terpenoid motif fused to an aromatic polyphenolic (resorcinol) structure. Inspired by the structure of this phytocannabinoid, we combined different natural product motifs with a benzo[d]imidazole scaffold to obtain a new library of compounds targeting the CB2 receptor. Here, we synthesized 26 new compounds, out of which 15 presented CB2 binding and 3 showed potent agonist activity. SAR analysis indicated that the presence of bulky aliphatic or aromatic natural product motifs at position 2 of the benzo[d]imidazoles ring linked by an electronegative atom is essential for receptor recognition, while substituents with moderate bulkiness at position 1 of the heterocyclic core also participate in receptor recognition. Compounds 5, 6, and 16 were further characterized through in vitro cAMP functional assay, showing potent EC50 values between 20 and 3 nM, and compound 6 presented a significant difference between the EC50 of pharmacologic activity (3.36 nM) and IC50 of toxicity (30-38 µM).

The Expression Analyses of GSK3B, VEGF, ANG1, and ANG2 in Human Brain Microvascular Endothelial Cells Treated with the Synthetic Cannabinoid XLR-11

The endocannabinoid system receptors, cannabinoid receptors type-1 (CBR-1) and -2 (CBR-2), are implicated in several behavioral and cognitive processes. Many studies have indicated a correlation between cannabinoid receptors and angiogenesis. The current study aims to reveal the possible molecular signaling involved in brain angiogenesis induced by the activation of CBR-1 and CBR-2. We investigated whether the synthetic cannabinoid XLR-11, an agonist of CBR-1 and CBR-2, influences the mRNA and protein expression of vascular endothelial growth factor (VEGF), angiopoietin-1 (ANG1) and -2 (ANG2) in human brain microvascular endothelial cells (hBMVEs). Furthermore, we determined the phosphorylation of glycogen synthase kinase 3 beta (GSK3B) expression. Treatment of hBMVEs cells with XLR-11 elevated the mRNA levels of VEGF, ANG1, and ANG2. The secretion of these proangiogenic factors was increased in the media. Furthermore, the intracellular expression of VEGF, ANG1, ANG2, and GSK3B was significantly increased. This current research provides a new possible approach by targeting the cannabinoid receptors to control and regulate brain angiogenesis for treating a variety of angiogenesis-related diseases. This could be achived by using different agonists or antagonists of the cannabinoid receptors based on the nature of the diseases.

Cannabinoids as Prospective Anti-Cancer Drugs: Mechanism of Action in Healthy and Cancer Cells

Endogenous and exogenous cannabinoids modulate many physiological and pathological processes by binding classical cannabinoid receptors 1 (CB1) or 2 (CB2) or non-cannabinoid receptors. Cannabinoids are known to exert antiproliferative, apoptotic, anti-migratory and anti-invasive effect on cancer cells by inducing or inhibiting various signaling cascades. In this chapter, we specifically emphasize the latest research works about the alterations in endocannabinoid system (ECS) components in malignancies and cancer cell proliferation, migration, invasion, angiogenesis, autophagy, and death by cannabinoid administration, emphasizing their mechanism of action, and give a future perspective for clinical use.

Endocannabinoids and related compounds as modulators of angiogenesis: Concepts and clinical significance

Vasculogenesis (the process of differentiation of angioblasts toward endothelial cells and de novo formation of crude vascular networks) and angiogenesis (the process of harmonized sprouting and dispersal of new capillaries from previously existing ones) are two fundamentally complementary processes, obligatory for maintaining physiological functioning of vascular system. In clinical practice, however, the later one is of more importance as it guarantees correct embryonic nourishment, accelerates wound healing processes, prevents uncontrolled cell growth and tumorigenesis, contributes in supplying nutritional demand following occlusion of coronary vessels and is in direct relation with development of diabetic retinopathy. Hence, discovery of novel molecules capable of modulating angiogenic events are of great clinical importance. Recent studies have demonstrated multiple angio-regulatory activities for endocannabinoid system modulators and endocannabinoid-like molecules, as well as their metabolizing enzymes. Hence, in present article, we reviewed the regulatory roles of these molecules on angiogenesis and described molecular mechanisms underlying them.

Use of Cannabis and Cannabinoids for Treatment of Cancer

The endocannabinoid system (ECS) is an ancient homeostasis mechanism operating from embryonic stages to adulthood. It controls the growth and development of many cells and cell lineages. Dysregulation of the components of the ECS may result in uncontrolled proliferation, adhesion, invasion, inhibition of apoptosis and increased vascularization, leading to the development of various malignancies. Cancer is the disease of uncontrolled cell division. In this review, we will discuss whether the changes to the ECS are a cause or a consequence of malignization and whether different tissues react differently to changes in the ECS. We will discuss the potential use of cannabinoids for treatment of cancer, focusing on primary outcome/care-tumor shrinkage and eradication, as well as secondary outcome/palliative care-improvement of life quality, including pain, appetite, sleep, and many more factors. Finally, we will complete this review with the chapter on sex- and gender-specific differences in ECS and response to cannabinoids, and equality of the access to treatments with cannabinoids.

The Therapeutic Potential of the Endocannabinoid System in Age-Related Diseases

The endocannabinoid system (ECS) dynamically regulates many aspects of mammalian physiology. ECS has gained substantial interest since growing evidence suggests that it also plays a major role in several pathophysiological conditions due to its ability to modulate various underlying mechanisms. Furthermore, cannabinoids, as components of the cannabinoid system (CS), have proven beneficial effects such as anti-inflammatory, immunomodulatory, neuromodulatory, antioxidative, and cardioprotective effects. In this comprehensive review, we aimed to describe the complex interaction between CS and most common age-related diseases such as neuro-degenerative, oncological, skeletal, and cardiovascular disorders, together with the potential of various cannabinoids to ameliorate the progression of these disorders. Since chronic inflammation is postulated as the pillar of all the above-mentioned medical conditions, we also discuss in this paper the potential of CS to ameliorate aging-associated immune system dysregulation.

Comparison of the in vitro Anti-Inflammatory Effect of Cannabidiol to Dexamethasone

Background

Cannabidiol (CBD) is a non-psychoactive phytocannabinoid constituent of Cannabis sativa with pain-relieving and anti-inflammatory properties. With the emphasis on natural ingredients in cosmetics, CBD has become a new cosmetic ingredient due to its ability to alleviate inflammation. However, in-depth studies that directly compare the effective mechanism and the therapeutic potential of CBD are still needed.

Purpose

The aim of the present study was to investigate the anti-inflammatory effect of CBD in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and compare it to dexamethasone (DEX).

Methods

RAW264.7 macrophages in the logarithmic growth phase were incubated in the presence or absence of LPS. After that, the production of nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were measured. A luciferase reporter assay for nuclear factor kappa B (NF-κB) was performed, and the phosphorylation levels of the mitogen-activated protein kinase (MAPK) and NF-κB signaling pathways were measured.

Results

The present study indicated that CBD had a similar anti-inflammatory effect to DEX by attenuating the LPS-induced production of NO, IL-6, and TNF-α. However, only CBD attenuated JNK phosphorylation levels, and only DEX attenuated IKK phosphorylation levels.

Conclusion

These results suggested that CBD and DEX exhibit similar anti-inflammatory effects on LPS-induced RAW264.7 macrophages mainly through suppressing the MAPK and NF-κB signaling pathways, but with different intracellular mechanisms. These findings suggested that CBD may be considered a natural anti-inflammatory agent for protecting skin from immune disorders.

Cannabis as a potential compound against various malignancies, legal aspects, advancement by exploiting nanotechnology and clinical trials

Various preclinical and clinical studies exhibited the potential of cannabis against various diseases, including cancer and related pain. Subsequently, many efforts have been made to establish and develop cannabis-related products and make them available as prescription products. Moreover, FDA has already approved some cannabis-related products, and more advancement in this aspect is still going on. However, the approved product of cannabis is in oral dosage form, which exerts various limitations to achieve maximum therapeutic effects. A considerable translation is on a hike to improve bioavailability, and ultimately, the therapeutic efficacy of cannabis by the employment of nanotechnology. Besides the well-known psychotropic effects of cannabis upon the use at high doses, literature has also shown the importance of cannabis and its constituents in minimising the lethality of cancer in the preclinical models. This review discusses the history of cannabis, its legal aspect, safety profile, the mechanism by which cannabis combats with cancer, and the advancement of clinical therapy by exploiting nanotechnology. A brief discussion related to the role of cannabinoid in various cancers has also been incorporated. Lastly, the information regarding completed and ongoing trials have also been elaborated.

Synthetic Cannabinoid Agonist WIN 55212-2 Targets Proliferation, Angiogenesis, and Apoptosis via MAPK/AKT Signaling in Human Endometriotic Cell Lines and a Murine Model of Endometriosis

Endometriosis (EM) is characterized by the growth of endometrium-like tissue outside the uterus, leading to chronic inflammation and pelvic pain. Lesion proliferation, vascularization, and associated inflammation are the hallmark features of EM lesions. The legalization of recreational cannabinoids has garnered interest in the patient community and is contributing to a greater incidence of self medication; however, it remains unknown if cannabinoids possess marked disease-modifying properties. In this study, we assess the effects of synthetic cannabinoid, WIN 55212-2 (WIN 55), in EM-representative in vitro and in vivo syngeneic mouse models. WIN 55 reduced proliferation and angiogenesis in vitro, via MAPK/Akt-mediated apoptosis. These findings were corroborated in a mouse model of EM, where we found reduced TRPV1 expression in the dorsal root ganglia of the EM mouse model exposed to WIN 55, suggesting reduced signaling of pain stimuli. Ultimately, these pieces of evidence support the use of cannabinoid receptor agonists as a potential therapeutic intervention for EM associated pain and inflammation.

Efficacy of cannabinoids against glioblastoma multiforme: A systematic review

INTRODUCTION

The increased incidence of Glioblastoma Multiforme, the most aggressive and most common primary brain tumour, is evident worldwide. Survival rates are reaching only 15 months due to its high recurrence and resistance to current combination therapies including oncotomy, radiotherapy and chemotherapy. Light has been shed in the recent years on the anticancer properties of cannabinoids from Cannabis sativa.

OBJECTIVE

To determine whether cannabinoids alone or in combination with radiotherapy and/or chemotherapy inhibit tumour progression, induce cancer cell death, inhibit metastasis and invasiveness and the mechanisms that underlie these actions.

METHOD

PubMed and Web of Science were used for a systemic search to find studies on the anticancer effects of natural cannabinoids on glioma cancer cells in vitro and/or in vivo.

RESULTS

A total of 302 papers were identified, of which 14 studies were found to fit the inclusion criteria. 5 studies were conducted in vitro, 2 in vivo and 7 were both in vivo and in vitro. 3 studies examined the efficacy of CBD, THC and TMZ, 1 study examined CBD and radiation, 2 studies examined efficacy of THC only and 3 studies examined the efficacy of CBD only. 1 study examined the efficacy of CBD, THC and radiotherapy, 2 studies examined the combination of CBD and THC and 2 more studies examined the efficacy of CBD and TMZ.

CONCLUSION

The evidence in this systematic review leads to the conclusion that cannabinoids possess anticancer potencies against glioma cells, however this effect varies with the combinations and dosages used. Studies so far were conducted on cells in culture and on mice as well as a small number of studies that were conducted on humans. Hence in order to have more accurate results, higher quality studies mainly including human clinical trials with larger sample sizes are necessitated urgently for GBM treatment.

Therapeutic Attributes of Endocannabinoid System against Neuro-Inflammatory Autoimmune Disorders

In humans, various sites like cannabinoid receptors (CBR) having a binding affinity with cannabinoids are distributed on the surface of different cell types, where endocannabinoids (ECs) and derivatives of fatty acid can bind. The binding of these substance(s) triggers the activation of specific receptors required for various physiological functions, including pain sensation, memory, and appetite. The ECs and CBR perform multiple functions via the cannabinoid receptor 1 (CB1); cannabinoid receptor 2 (CB2), having a key effect in restraining neurotransmitters and the arrangement of cytokines. The role of cannabinoids in the immune system is illustrated because of their immunosuppressive characteristics. These characteristics include inhibition of leucocyte proliferation, T cells apoptosis, and induction of macrophages along with reduced pro-inflammatory cytokines secretion. The review seeks to discuss the functional relationship between the endocannabinoid system (ECS) and anti-tumor characteristics of cannabinoids in various cancers. The therapeutic potential of cannabinoids for cancer-both in vivo and in vitro clinical trials-has also been highlighted and reported to be effective in mice models in arthritis for the inflammation reduction, neuropathic pain, positive effect in multiple sclerosis and type-1 diabetes mellitus, and found beneficial for treating in various cancers. In human models, such studies are limited; thereby, further research is indispensable in this field to get a conclusive outcome. Therefore, in autoimmune disorders, therapeutic cannabinoids can serve as promising immunosuppressive and anti-fibrotic agents.

The Interplay between the Immune and the Endocannabinoid Systems in Cancer

The therapeutic potential of Cannabis sativa has been recognized since ancient times. Phytocannabinoids, endocannabinoids and synthetic cannabinoids activate two major G protein-coupled receptors, subtype 1 and 2 (CB1 and CB2). Cannabinoids (CBs) modulate several aspects of cancer cells, such as apoptosis, autophagy, proliferation, migration, epithelial-to-mesenchymal transition and stemness. Moreover, agonists of CB1 and CB2 receptors inhibit angiogenesis and lymphangiogenesis in vitro and in vivo. Low-grade inflammation is a hallmark of cancer in the tumor microenvironment (TME), which contains a plethora of innate and adaptive immune cells. These cells play a central role in tumor initiation and growth and the formation of metastasis. CB2 and, to a lesser extent, CB1 receptors are expressed on a variety of immune cells present in TME (e.g., T cells, macrophages, mast cells, neutrophils, NK cells, dendritic cells, monocytes, eosinophils). The activation of CB receptors modulates a variety of biological effects on cells of the adaptive and innate immune system. The expression of CB2 and CB1 on different subsets of immune cells in TME and hence in tumor development is incompletely characterized. The recent characterization of the human cannabinoid receptor CB2-G_i signaling complex will likely aid to design potent and specific CB2/CB1 ligands with therapeutic potential in cancer.

Can Cannabidiol Affect the Efficacy of Chemotherapy and Epigenetic Treatments in Cancer?

The success of cannabinoids with chronic neuropathic pain and anxiety has been demonstrated in a multitude of studies. With the high availability of a non-intoxicating compound, cannabidiol (CBD), an over-the-counter medication, has generated heightened interest in its use in the field of oncology. This review focuses on the widespread therapeutic potential of CBD with regard to enhanced wound healing, lowered toxicity profiles of chemotherapeutics, and augmented antitumorigenic effects. The current literature is sparse with regard to determining the clinically relevant concentrations of CBD given the biphasic nature of the compound’s response. Therefore, there is an imminent need for further dose-finding studies in order to determine the optimal dose of CBD for both intermittent and regular users. We address the potential influence of regular or occasional CBD usage on therapeutic outcomes in ovarian cancer patients. Additionally, as the development of chemoresistance in ovarian cancer results in treatment failure, the potential for CBD to augment the efficacy of conventional chemotherapeutic and epigenetic drugs is a topic of significant importance. Our review is focused on the widespread therapeutic potential of CBD and whether or not a synergistic role exists in combination with epigenetic and classic chemotherapy medications.

Cancer Initiation, Progression and Resistance: Are Phytocannabinoids from Cannabis sativa L. Promising Compounds?

Cannabis sativa L. is a source of over 150 active compounds known as phytocannabinoids that are receiving renewed interest due to their diverse pharmacologic activities. Indeed, phytocannabinoids mimic the endogenous bioactive endocannabinoids effects through activation of CB1 and CB2 receptors widely described in the central nervous system and peripheral tissues. All phytocannabinoids have been studied for their protective actions towards different biological mechanisms, including inflammation, immune response, oxidative stress that, altogether, result in an inhibitory activity against the carcinogenesis. The role of the endocannabinoid system is not yet completely clear in cancer, but several studies indicate that cannabinoid receptors and endogenous ligands are overexpressed in different tumor tissues. Recently, in vitro and in vivo evidence support the effectiveness of phytocannabinoids against various cancer types, in terms of proliferation, metastasis, and angiogenesis, actions partially due to their ability to regulate signaling pathways critical for cell growth and survival. The aim of this review was to report the current knowledge about the action of phytocannabinoids from Cannabis sativa L. against cancer initiation and progression with a specific regard to brain, breast, colorectal, and lung cancer as well as their possible use in the therapies. We will also report the known molecular mechanisms responsible for such positive effects. Finally, we will describe the actual therapeutic options for Cannabis sativa L. and the ongoing clinical trials.

The Neuroprotective Properties, Functions, and Roles of Cannabis sativa in Selected Diseases Related to the Nervous System

BACKGROUND

Cannabis and its extracts are now being explored due to their huge health benefits. Although, the effect they elicit, whether on humans or rodents, may vary based on the age of the animal/subject and or the time in which the extract is administered. However, several debates exist concerning the various medical applications of these compounds. Nonetheless, their applicability as therapeutics should not be clouded based on their perceived negative biological actions.

METHODS

Articles from reliable databases such as Science Direct, PubMed, Google Scholar, Scopus, and Ovid were searched. Specific search methods were employed using multiple keywords: ''Medicinal Cannabis; endocannabinoid system; cannabinoids receptors; cannabinoids and cognition; brain disorders; neurodegenerative diseases''. For the inclusion/exclusion criteria, only relevant articles related to medicinal Cannabis and its various compounds were considered.

RESULTS

The current review highlights the role, effects, and involvement of Cannabis, cannabinoids, and endocannabinoids in preventing selected neurodegenerative diseases and possible amelioration of cognitive impairments. Furthermore, it also focuses on Cannabis utilization in many disease conditions such as Alzheimer's and Parkinson's disease among others.

CONCLUSION

In conclusion, the usage of Cannabis should be further explored as accumulating evidence suggests that it could be effective and somewhat safe, especially when adhered to the recommended dosage. Furthermore, in-depth studies should be conducted in order to unravel the specific mechanism underpinning the involvement of cannabinoids at the cellular level and their therapeutic applications.

Cannabinoids as Key Regulators of Inflammasome Signaling: A Current Perspective

Inflammasomes are cytoplasmic inflammatory signaling protein complexes that detect microbial materials, sterile inflammatory insults, and certain host-derived elements. Inflammasomes, once activated, promote caspase-1–mediated maturation and secretion of pro-inflammatory cytokines, interleukin (IL)-1β and IL-18, leading to pyroptosis. Current advances in inflammasome research support their involvement in the development of chronic inflammatory disorders in contrast to their role in regulating innate immunity. Cannabis (marijuana) is a natural product obtained from the Cannabis sativa plant, and pharmacologically active ingredients of the plant are referred to as cannabinoids. Cannabinoids and cannabis extracts have recently emerged as promising novel drugs for chronic medical conditions. Growing evidence indicates the potent anti-inflammatory potential of cannabinoids, especially Δ⁹-tetrahydrocannabinol (Δ⁹-THC), cannabidiol (CBD), and synthetic cannabinoids; however, the mechanisms remain unclear. Several attempts have been made to decipher the role of cannabinoids in modulating inflammasome signaling in the etiology of chronic inflammatory diseases. In this review, we discuss recently published evidence on the effect of cannabinoids on inflammasome signaling. We also discuss the contribution of various cannabinoids in human diseases concerning inflammasome regulation. Lastly, in the milieu of coronavirus disease-2019 (COVID-19) pandemic, we confer available evidence linking inflammasome activation to the pathophysiology of COVID-19 suggesting overall, the importance of cannabinoids as possible drugs to target inflammasome activation in or to support the treatment of a variety of human disorders including COVID-19.

A Research Domain Criteria Approach to Gambling Disorder and Behavioral Addictions: Decision-Making, Response Inhibition, and the Role of Cannabidiol

Gambling Disorder (GD) has been recently re-classified in the DSM-5 under the "substance-related and addictive disorders," in light of its genetic, endophenotypic, and phenotypic resemblances to substance dependence. Diminished control is a core defining concept of psychoactive substance dependence or addiction and has given rise to the concept of "behavioral" addictions, which are syndromes analogous to substance addiction, but with a behavioral focus other than ingestion of a psychoactive substance. The main symptom clusters are represented by loss of control, craving/withdrawal, and neglect of other areas of life, whereas in a Research Domain Criteria (RDoC) perspective, GD patients exhibit deficits in the domain of "Positive valence systems," particularly in the "Approach motivation" and "Reward learning" constructs, as well as in the "Cognitive systems," primarily in the "Cognitive control" construct. In the Addictions Neuroclinical Assessment (ANA), three relevant domains for addictions emerge: "Incentive salience," "Negative Emotionality," and "Executive Function." The endocannabinoid system (ECS) may largely modulate these circuits, presenting a promising pharmaceutical avenue for treating addictions. Up to now, research on cannabidiol has shown some efficacy in Attention Deficit/Hyperactivity Disorder (ADHD), whereas in behavioral addictions its role has not been fully elucidated, as well as its precise action on RDoC domains. Herein, we review available evidence on RDoC domains affected in GD and behavioral addictions and summarize insights on the use of cannabidiol in those disorders and its potential mechanisms of action on reward, decisional, and sensorimotor processes.

(Endo)Cannabinoids and Gynaecological Cancers

Simple Summary

Cancers of the female reproductive system are common and are responsible for a large number of deaths in women. The exact reasons why some of these cancers occur are unknown. It is, however, known that for most of these cancers, several factors interact for them to happen. These interactions involve factors external and internal to the woman. An understanding of some of the internal factors involved in how these cancers arise will not only help drive preventive strategies, but will speed the development of new treatment approaches. The endocannabinoid system is a family including chemicals (known as endocannabinoids) produced in the body that are similar to those derived from the cannabis plant. This system, which is widely distributed in the body, has been shown to be involved in various functions. Its disruption has been shown to lead to various diseases, one of which is cancer. In this review, we summarise current knowledge of this system, its various constituents, and how they are involved in reproductive events and their pathologies, especially cancers. Furthermore, we discuss the role of the endocannabinoid system in these cancers and how targeting it could lead to new approaches to diagnosis and treatment of cancers of the female reproductive system.

Abstract

Gynaecological cancers can be primary neoplasms, originating either from the reproductive tract or the products of conception, or secondary neoplasms, representative of metastatic disease. For some of these cancers, the exact causes are unknown; however, it is recognised that the precise aetiopathogeneses for most are multifactorial and include exogenous (such as diet) and endogenous factors (such as genetic predisposition), which mutually interact in a complex manner. One factor that has been recognised to be involved in the pathogenesis and progression of gynaecological cancers is the endocannabinoid system (ECS). The ECS consists of endocannabinoids (bioactive lipids), their receptors, and metabolic enzymes responsible for their synthesis and degradation. In this review, the impact of plant-derived (Cannabis species) cannabinoids and endocannabinoids on gynaecological cancers will be discussed within the context of the complexity of the proteins that bind, transport, and metabolise these compounds in reproductive and other tissues. In particular, the potential of endocannabinoids, their receptors, and metabolic enzymes as biomarkers of specific cancers, such as those of the endometrium, will be addressed. Additionally, the therapeutic potential of targeting selected elements of the ECS as new action points for the development of innovative drugs will be presented.

A Review of the Current Evidence Connecting Seborrheic Dermatitis and Parkinson’s Disease and the Potential Role of Oral Cannabinoids

Parkinson’s disease (PD) is a neurodegenerative disorder associated with multiple comorbidities, including seborrheic dermatitis (SD), which develops in more than half of PD patients. SD in patients with PD can be severe and frequently intractable by traditional topical therapy. Cannabinoids possess anti-inflammatory and neuromodulatory properties working within the intrinsic endocannabinoid system, the activation of which may alleviate the motor symptoms of PD. The effect of cannabinoids on SD is unknown. Here we explore the pathophysiological mechanisms and possible therapeutic role of oral cannabinoids in PD patients with SD, and review speculative mechanisms underlying the association of PD and SD. Current data supporting the use of cannabinoids in both PD and SD, as well as oral cannabinoid safety and tolerability, are presented. Cannabinoids may provide the possibility of simultaneous treatment of both SD and PD. Specific SD studies and additional safety data on oral cannabinoids are needed.

Roles of Cannabinoids in Melanoma: Evidence from In Vivo Studies

Melanoma is the fourth most common type of cancer diagnosed in Australians after breast, prostate, and colorectal cancers. While there has been substantial progress in the treatment of cancer in general, malignant melanoma, in particular, is resistant to existing medical therapies requiring an urgent need to develop effective treatments with lesser side effects. Several studies have shown that "cannabinoids", the major compounds of the Cannabis sativaL. plant, can reduce cell proliferation and induce apoptosis in melanoma cells. Despite prohibited use of Cannabis in most parts of the world, in recent years there have been renewed interests in exploiting the beneficial health effects of the Cannabis plant-derived compounds. Therefore, the aim of this study was in the first instance to review the evidence from in vivo studies on the effects of cannabinoids on melanoma. Systematic searches were carried out in PubMed, Embase, Scopus, and ProQuest Central databases for relevant articles published from inception. From a total of 622 potential studies, six in vivo studies assessing the use of cannabinoids for treatment of melanoma were deemed eligible for the final analysis. The findings revealed cannabinoids, individually or combined, reduced tumor growth and promoted apoptosis and autophagy in melanoma cells. Further preclinical and animal studies are required to determine the underlying mechanisms of cannabinoids-mediated inhibition of cancer-signaling pathways. Well-structured, randomized clinical studies on cannabinoid use in melanoma patients would also be required prior to cannabinoids becoming a viable and recognized therapeutic option for melanoma treatment in patients.

Cannabidiol as a Novel Therapeutic for Immune Modulation

The immune-suppressive effects of cannabidiol (CBD) are attributed to the modulation of essential immunological signaling pathways and receptors. Mechanistic understanding of the pharmacological effects of CBD emphasizes the therapeutic potential of CBD as a novel immune modulator. Studies have observed that the antagonists of CB₁ and CB₂ receptors and transient receptor potential vanilloid 1 reverse the immunomodulatory effects of CBD. CBD also inhibits critical activators of the Janus kinase/signal transducer and activator of transcription signaling pathway, as well as the nucleotide-binding oligomerization domain-like receptor signaling pathway, in turn decreasing pro-inflammatory cytokine production. Furthermore, CBD protects against cellular damage incurred during immune responses by modulating adenosine signaling. Ultimately, the data overwhelmingly support the immunosuppressive effects of CBD and this timely review draws attention to the prospective development of CBD as an effective immune modulatory therapeutic.

Anti-Cancer Potential of Cannabinoids, Terpenes, and Flavonoids Present in Cannabis

In recent years, and even more since its legalization in several jurisdictions, cannabis and the endocannabinoid system have received an increasing amount of interest related to their potential exploitation in clinical settings. Cannabinoids have been suggested and shown to be effective in the treatment of various conditions. In cancer, the endocannabinoid system is altered in numerous types of tumours and can relate to cancer prognosis and disease outcome. Additionally, cannabinoids display anticancer effects in several models by suppressing the proliferation, migration and/or invasion of cancer cells, as well as tumour angiogenesis. However, the therapeutic use of cannabinoids is currently limited to the treatment of symptoms and pain associated with chemotherapy, while their potential use as cytotoxic drugs in chemotherapy still requires validation in patients. Along with cannabinoids, cannabis contains several other compounds that have also been shown to exert anti-tumorigenic actions. The potential anti-cancer effects of cannabinoids, terpenes and flavonoids, present in cannabis, are explored in this literature review.

Urine Endocannabinoids as Novel Non-Invasive Biomarkers for Bladder Cancer at Early Stage

Due to the involvement of the endocannabinoid system (ECS) in cancer onset and progression and the less studied connection between ECS and bladder cancer, here an evaluation of the ECS modifications associated with bladder cancer is reported. Urine samples were collected from healthy volunteers and patients with bladder cancer at different grades. Endocannabinoids (ECs) and N-acylethanolamides (NAEs) were quantified by HPLC-MS/MS and results normalized for creatinine content. An increase in the urine concentrations of four ECs and NAEs analyzed was observed with a statistically significant increase in the arachidonoylethanolamide (AEA) and stearoylethanoamide (SEA) associated with bladder cancer. Receiver operating characteristic curves built with AEA and SEA data allowed the selection of 160 pg/mL for SEA (area under the curve (AUC) = 0.91, Selectivity (SE) 94%, Specificity (SP) 45%) and 8 pg/mL for AEA (AUC = 0.85, SE 94%, SP 61%) as the best cut-off values. Moreover, data from bladder cancer samples at different grades were derived from The Cancer Genome Atlas, and the expressions of thirteen different components of the “endocannabinoidome” were analyzed. Statistical analysis highlights significant variations in the expression of three enzymes involved in EC and NAE turnover in bladder cancer.

The Endocannabinoid System: A Target for Cancer Treatment

In recent years, the endocannabinoid system has received great interest as a potential therapeutic target in numerous pathological conditions. Cannabinoids have shown an anticancer potential by modulating several pathways involved in cell growth, differentiation, migration, and angiogenesis. However, the therapeutic efficacy of cannabinoids is limited to the treatment of chemotherapy-induced symptoms or cancer pain, but their use as anticancer drugs in chemotherapeutic protocols requires further investigation. In this paper, we reviewed the role of cannabinoids in the modulation of signaling mechanisms implicated in tumor progression.

Cannabidiol-from Plant to Human Body: A Promising Bioactive Molecule with Multi-Target Effects in Cancer

Cannabis sativa L. is a plant long used for its textile fibers, seed oil, and oleoresin with medicinal and psychoactive properties. It is the main source of phytocannabinoids, with over 100 compounds detected so far. In recent years, a lot of attention has been given to the main phytochemicals present in Cannabis sativa L., namely, cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC). Compared to THC, CBD has non-psychoactive effects, an advantage for clinical applications of anti-tumor benefits. The review is designed to provide an update regarding the multi-target effects of CBD in different types of cancer. The main focus is on the latest in vitro and in vivo studies that present data regarding the anti-proliferative, pro-apoptotic, cytotoxic, anti-invasive, anti-antiangiogenic, anti-inflammatory, and immunomodulatory properties of CBD together with their mechanisms of action. The latest clinical evidence of the anticancer effects of CBD is also outlined. Moreover, the main aspects of the pharmacological and toxicological profiles are given.

Antitumor Cannabinoid Chemotypes: Structural Insights

Cannabis has long been known to limit or prevent nausea and vomiting, lack of appetite, and pain. For this reason, cannabinoids have been successfully used in the treatment of some of the unwanted side effects caused by cancer chemotherapy. Besides their palliative effects, research from the past two decades has demonstrated their promising potential as antitumor agents in a wide variety of tumors. Cannabinoids of endogenous, phytogenic, and synthetic nature have been shown to impact the proliferation of cancer through the modulation of different proteins involved in the endocannabinoid system such as the G protein-coupled receptors CB1, CB2, and GRP55, the ionotropic receptor TRPV1, or the fatty acid amide hydrolase (FAAH). In this article, we aim to structurally classify the antitumor cannabinoid chemotypes described so far according to their targets and types of cancer. In a drug discovery approach, their in silico pharmacokinetic profile has been evaluated in order to identify appropriate drug-like profiles, which should be taken into account for further progress toward the clinic. This analysis may provide structural insights into the selection of specific cannabinoid scaffolds for the development of antitumor drugs for the treatment of particular types of cancer.

Therapeutic applications of cannabinoids

The psychoactive property of cannabinoids is well known and there has been a continuous controversy regarding the usage of these compounds for therapeutic purposes all over the world. Their use for medical and research purposes are restricted in various countries. However, their utility as medications should not be overshadowed by its negative physiological activities. This review article is focused on the therapeutic potential and applications of phytocannabinoids and endocannabinoids. We further highlights their mode of action, overall effects on physiology, various in vitro and in vivo studies that have been done so far and the extent to which these compounds can be useful in different disease conditions such as cancer, Alzheimer's disease, multiple sclerosis, pain, inflammation, glaucoma and many others. Thus, this work is an attempt to make the readers understand the positive implications of these compounds and indicates the significant developments of utilizing cannabinoids as therapeutic agents.

Involvement of the CB2 cannabinoid receptor in cell growth inhibition and G0/G1 cell cycle arrest via the cannabinoid agonist WIN 55,212-2 in renal cell carcinoma

BACKGROUND

The anti-tumor properties of cannabinoids have been investigated in many in vitro and in vivo studies. Many of these anti-tumor effects are mediated via cannabinoid receptor types 1 and 2 (CB₁ and CB₂), comprising the endocannabinoid system (ECS). In this study, we investigated the ECS based on CB ₁ and CB ₂ receptor gene and protein expression in renal cell carcinoma (RCC) cell lines. In view of their further use for potential treatments, we thus investigated the roles of CB₁ and CB₂ receptors in the anti-proliferative action and signal transduction triggered by synthetic cannabinoid agonists [such as JWH-133 and WIN 55,212-2 (WIN-55)] in RCC cell lines.

METHODS

Human RCC cell lines were used for this study. The CB ₁ and CB ₂ gene expression levels were analyzed using real-time PCR. Flow cytometric, immunocytochemical and western blot analyses were performed to confirm CB₁ and CB₂ receptor protein expression. The anti-proliferative effects of synthetic cannabinoids were investigated on cell viability assay. The CB₁ and CB₂ receptors were blocked pharmacologically with the antagonists SR141716A and AM-630, respectively, to investigate the effects of the agonists JWH-133 and WIN-55. Cell cycle, apoptosis and LDH-based cytotoxicity were analyzed on cannabinoid-treated RCC cells.

RESULTS

The CB1 and CB2 genes expression was shown by real-time PCR and flow cytometric and western blot analysis indicating a higher level of CB₂ receptor as compared to CB₁ in RCC cells. Immunocytochemical staining also confirmed the expression of the CB₁ and CB₂ proteins. We also found that the synthetic cannabinoid agonist WIN-55 exerted anti-proliferative and cytotoxic effects by inhibiting the growth of RCC cell lines, while the CB₂ agonist JWH-133 did not. Pharmacologically blocking the CB1 and CB2 receptors with their respective antagonists SR141716A and AM-630, followed by the WIN-55 treatment of RCC cells allowed uncovering the involvement of CB2, which led to an arrest in the G0/G1 phase of the cell cycle and apoptosis.

CONCLUSIONS

This study elucidated the involvement of CB₂ in the in vitro inhibition of RCC cells, and future applications of CB₂ agonists in the prevention and management of RCC are discussed.

Effects of cell-cell crosstalk on gene expression patterns in a cell model of renal cell carcinoma lung metastasis

The median survival rate of patients with metastatic renal carcinoma is approximately 10 to 12 months, with up to 50% of patients developing metastases in the lung parenchyma. The molecular basis for metastatic development remains unclear. In the present study, we used renal cell carcinoma (RCC) cells and bronchial epithelial cells, representing metastasis target organ cells, conditioned medium and co-culture models to identify specific gene expression changes responsible for cancer cell viability in a metastatic microenvironment. RCC cell proliferation and migration increased when the culture was supplemented with conditioned medium from lung fibroblasts or pleural epithelial cells. Healthy epithelial cells were, in turn, also stimulated with conditioned medium from RCC cell lines. The mitogen-activated protein kinase (MAPK), interleukin (IL)-6, and phosphatidylinositol 4,5-bisphosphate (PIP2) signaling pathways were identified as deregulated upon cell‑cell interaction. Thus, cell-cell communication may contribute to the development of the metastatic niche. The identified deregulated signaling pathways may be considered as potential therapeutic targets in metastatic renal carcinoma.

The Search for an Effective Therapy to Treat Fragile X Syndrome: Dream or Reality?

Fragile X Syndrome (FXS) is the most common form of intellectual disability and a primary cause of autism. It originates from the lack of the Fragile X Mental Retardation Protein (FMRP), which is an RNA-binding protein encoded by the Fragile X Mental Retardation Gene 1 (FMR1) gene. Multiple roles have been attributed to this protein, ranging from RNA transport (from the nucleus to the cytoplasm, but also along neurites) to translational control of mRNAs. Over the last 20 years many studies have found a large number of FMRP mRNA targets, but it is still not clear which are those playing a critical role in the etiology of FXS. So far, no therapy for FXS has been found, making the quest for novel targets of considerable importance. Several pharmacological approaches have been attempted, but, despite some promising preclinical results, no strategy gave successful outcomes, due either to the induction of major side effects or to the lack of improvement of the phenotypes. However, these studies suggested that, in order to measure the effectiveness of a specific treatment, trials should be redesigned and new endpoints defined in FXS patients. Nevertheless, the search for new therapeutic targets for FXS is very active. In this context, the advances in animal modeling, coupled with better understanding of neurobiology and physiopathology of FXS, are of crucial importance in developing new selected treatments. Here, we discuss the pathways that were recently linked to the physiopathology of FXS (mGluR, GABAR, insulin, Insulin-like Growth Factor 1 (IGF-1), MPP-9, serotonin, oxytocin and endocannabinoid signaling) and that suggest new approaches to find an effective therapy for this disorder. Our goal with this review article is to summarize some recent relevant findings on FXS treatment strategies in order to have a clearer view of the different pathways analyzed to date emphasizing those shared with other synaptic disorders.