CB2 cannabinoid receptor activation promotes colon cancer progression via AKT/GSK3β signaling pathway

Priming lymphocyte responsiveness and differential T cell signaling in pediatric IBD patients with Cannabis use

The prevalence of inflammatory bowel disease (IBD) has increased dramatically in recent years, particularly in pediatric populations. Successful remission with current therapies is limited and often transient, leading patients to seek alternative therapies for symptom relief, including the use of medical marijuana (Cannabis sativa). However, chronic cannabis use among IBD patients is associated with increased risk for surgical interventions. Therefore, determining the direct impact of cannabis use on immune modulation in IBD patients is of critical importance. Peripheral blood mononuclear cells of cannabis using and non-using pediatric IBD patients were phenotyped by flow cytometry and functionally assessed for their cytokine production profile. A phospho-kinase array was also performed to better understand changes in immune responses. Results were then compared with serum phytocannabinoid profiles of each patient to identify cannabinoid-correlated changes in immune responses. Results demonstrated elevated levels of a myriad of pro-inflammatory cytokines in users versus non-users. Differences in signaling cascades of activated T cells between users and non-users were also observed. A number of anti-inflammatory cytokines were inversely correlated with serum phytocannabinoids. These results suggest that cannabis exposure, which can desensitize cannabinoid receptors, may prime pro-inflammatory pathways in pediatric IBD patients.

Diffractaic acid exhibits thioredoxin reductase 1 inhibition in lung cancer A549 cells

Lung cancer is the leading cause of cancer-related deaths all over the world. Therefore, it has gained importance in the development of new chemotherapeutic strategies to identify anticancer agents with low side effects, reliable, high anticancer potential, and specific to lung cancer cells. Thioredoxin reductase 1 (TrxR1) is an important therapeutic target for lung cancer treatment because of its overexpression in tumor cells. Here, we aimed to examine the anticancer effect of diffractaic acid, a lichen secondary metabolite, in A549 cells by comparing it with the commercial chemotherapeutic drug carboplatin and also to investigate whether the anticancer effect of diffractaic acid occurs via TrxR1-targeting. The IC50 value of diffractaic acid on A549 cells was determined as 46.37 μg/mL at 48 h, and diffractaic acid had stronger cytotoxicity than carboplatin in A549 cells. qPCR results revealed that diffractaic acid promoted the intrinsic apoptotic pathway through the upregulation of the BAX/BCL2 ratio and P53 gene in A549 cells, which is consistent with the flow cytometry results. Furthermore, migration analysis results indicated that diffractaic acid impressively suppressed the migration of A549 cells. While the enzymatic activity of TrxR1 was inhibited by diffractaic acid in A549 cells, no changes were seen in the quantitative expression levels of gene and protein. These findings provide fundamental data on the anticancer effect of diffractaic acid on A549 cells targeting TrxR1 activity, suggesting that it could be considered a chemotherapeutic agent for lung cancer therapy.

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.

Crosstalk between cannabinoid receptor 2 and lysophosphatidic acid receptor 5

Cannabinoid receptor 2 (CB₂) and lysophosphatidic acid receptor 5 (LPA₅) are both classified as G-protein coupled receptors (GPCRs) activated by bioactive lipids and are highly expressed in colon cancer cells. However, crosstalk between two receptors and its potential effects on cancer cell physiology have not been fully elucidated. In the present study, the results of bioluminescence resonance energy transfer analysis showed that, among the LPA receptors, CB₂ strongly and specifically interacted with LPA₅. Both receptors were co-localized in the plasma membrane in the absence of agonists, and the receptors were co-internalized upon activation of either receptor alone or both receptors together. We further investigated the effects of expression of both receptors on cell proliferation and migration, and the molecular mechanisms underlying these effects in HCT116 colon cancer cells. Co-expression of receptors significantly increased cell proliferation and migration by increasing Akt phosphorylation and tumor progression-related gene expression, whereas no such effect was seen upon expression of either receptor alone. These results suggest the possibility of physical and functional crosstalk between CB₂ and LPA₅.

The Anti-Tumorigenic Role of Cannabinoid Receptor 2 in Non-Melanoma Skin Cancer

Five million non-melanoma skin cancers occur globally each year, and it is one of the most common malignant cancers. The dysregulation of the endocannabinoid system, particularly cannabinoid receptor 2 (CB2), is implicated in skin cancer development, progression, and metastasis. Comparing wildtype (WT) to systemic CB2 knockout (CB2^-/-) mice, we performed a spontaneous cancer study in one-year old mice, and subsequently used the multi-stage chemical carcinogenesis model, wherein cancer is initiated by 7,12-dimethylbenz[a]anthracene (DMBA) and promoted by 12-O-tetradecanoylphorbol-13-acetate (TPA). We found that aging CB2^-/- mice have an increased incidence of spontaneous cancerous and precancerous skin lesions compared to their WT counterparts. In the DMBA/TPA model, CB2^-/- developed more and larger papillomas, had decreased spontaneous regression of papillomas, and displayed an altered systemic immune profile, including upregulated CD4+ T cells and dendritic cells, compared to WT mice. Immune cell infiltration in the tumor microenvironment was generally low for both genotypes, although a trend of higher myeloid-derived suppressor cells was observed in the CB2^-/- mice. CB2 expression in carcinogen-exposed skin was significantly higher compared to naïve skin in WT mice, suggesting a role of CB2 on keratinocytes. Taken together, our data show that endogenous CB2 activation plays an anti-tumorigenic role in non-melanoma skin carcinogenesis, potentially via an immune-mediated response involving the alteration of T cells and myeloid cells coupled with the modulation of keratinocyte activity.

The Anti-Tumorigenic Role of Cannabinoid Receptor 2 in Colon Cancer: A Study in Mice and Humans

The endocannabinoid system, particularly cannabinoid receptor 2 (CB2 in mice and CNR2 in humans), has controversial pathophysiological implications in colon cancer. Here, we investigate the role of CB2 in potentiating the immune response in colon cancer in mice and determine the influence of CNR2 variants in humans. Comparing wild-type (WT) mice to CB2 knockout (CB2^-/-) mice, we performed a spontaneous cancer study in aging mice and subsequently used the AOM/DSS model of colitis-associated colorectal cancer and a model for hereditary colon cancer (Apc^Min/+). Additionally, we analyzed genomic data in a large human population to determine the relationship between CNR2 variants and colon cancer incidence. Aging CB2^-/- mice exhibited a higher incidence of spontaneous precancerous lesions in the colon compared to WT controls. The AOM/DSS-treated CB2^-/- and Apc^Min/+CB2^-/- mice experienced aggravated tumorigenesis and enhanced splenic populations of immunosuppressive myeloid-derived suppressor cells along with abated anti-tumor CD8+ T cells. Importantly, corroborative genomic data reveal a significant association between non-synonymous variants of CNR2 and the incidence of colon cancer in humans. Taken together, the results suggest that endogenous CB2 activation suppresses colon tumorigenesis by shifting the balance towards anti-tumor immune cells in mice and thus portray the prognostic value of CNR2 variants for colon cancer patients.

Potential Pathophysiological Pathways in the Complex Relationships between OSA and Cancer

Several epidemiological and clinical studies have suggested a relationship between obstructive sleep apnea (OSA) and a higher incidence or severity of cancer. This relationship appears to be dependent on a myriad of factors. These include non-modifiable factors, such as age and gender; and modifiable or preventable factors, such as specific comorbidities (especially obesity), the use of particular treatments, and, above all, the histological type or location of the cancer. Heterogeneity in the relationship between OSA and cancer is also related to the influences of intermittent hypoxemia (a hallmark feature of OSA), among others, on metabolism and the microenvironment of different types of tumoral cells. The hypoxia inducible transcription factor (HIF-1α), a molecule activated and expressed in situations of hypoxemia, seems to be key to enabling a variety of pathophysiological mechanisms that are becoming increasingly better recognized. These mechanisms appear to be operationally involved via alterations in different cellular functions (mainly involving the immune system) and molecular functions, and by inducing modifications in the microbiome. This, in turn, may individually or collectively increase the risk of cancer, which is then, further modulated by the genetic susceptibility of the individual. Here, we provide an updated and brief review of the different pathophysiological pathways that have been identified and could explain the relationship between OSA and cancer. We also identify future challenges that need to be overcome in this intriguing field of research.

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.

Disorders of cancer metabolism: The therapeutic potential of cannabinoids

Abnormal energy metabolism, as one of the important hallmarks of cancer, was induced by multiple carcinogenic factors and tumor-specific microenvironments. It comprises aerobic glycolysis, de novo lipid biosynthesis, and glutamine-dependent anaplerosis. Considering that metabolic reprogramming provides various nutrients for tumor survival and development, it has been considered a potential target for cancer therapy. Cannabinoids have been shown to exhibit a variety of anticancer activities by unclear mechanisms. This paper first reviews the recent progress of related signaling pathways (reactive oxygen species (ROS), AMP-activated protein kinase (AMPK), mitogen-activated protein kinases (MAPK), phosphoinositide 3-kinase (PI3K), hypoxia-inducible factor-1alpha (HIF-1α), and p53) mediating the reprogramming of cancer metabolism (including glucose metabolism, lipid metabolism, and amino acid metabolism). Then we comprehensively explore the latest discoveries and possible mechanisms of the anticancer effects of cannabinoids through the regulation of the above-mentioned related signaling pathways, to provide new targets and insights for cancer prevention and treatment.

Endocannabinoid-Binding Receptors as Drug Targets

Cannabis plant has been used from ancient times with therapeutic purposes for treating human pathologies, but the identification of the cellular and molecular mechanisms underlying the therapeutic properties of the phytocannabinoids, the active compounds in this plant, occurred in the last years of the past century. In the late 1980s and early 1990s, seminal studies demonstrated the existence of cannabinoid receptors and other elements of the so-called endocannabinoid system. These G protein-coupled receptors (GPCRs) are a key element in the functions assigned to endocannabinoids and appear to serve as promising pharmacological targets. They include CB₁, CB₂, and GPR55, but also non-GPCRs can be activated by endocannabinoids, like ionotropic receptor TRPV₁ and even nuclear receptors of the PPAR family. Their activation, inhibition, or simply modulation have been associated with numerous physiological effects at both central and peripheral levels, which may have therapeutic value in different human pathologies, then providing a solid experimental explanation for both the ancient medicinal uses of Cannabis plant and the recent advances in the development of cannabinoid-based specific therapies. This chapter will review the scientific knowledge generated in the last years around the research on the different endocannabinoid-binding receptors and their signaling mechanisms. Our intention is that this knowledge may help readers to understand the relevance of these receptors in health and disease conditions, as well as it may serve as the theoretical basis for the different experimental protocols to investigate these receptors and their signaling mechanisms that will be described in the following chapters.

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.

Influence of Inhibition of COX-2-Dependent Lipid Metabolism on Regulation of UVB-Induced Keratinocytes Apoptosis by Cannabinoids

Inflammation and apoptosis are regulated by similar factors, including ultraviolet B (UVB) radiation and cannabinoids, which are metabolized by cyclooxygenase-2 (COX-2) into pro-apoptotic prostaglandin derivatives. Thus, the aim of this study was to evaluate the impact of cyclooxygenase-2 inhibition by celecoxib on the apoptosis of keratinocytes modulated by UVB, anandamide (AEA) and cannabidiol (CBD). For this purpose, keratinocytes were non-treated/treated with celecoxib and/or with UVB and CBD and AEA. Apoptosis was evaluated using microscopy, gene expressions using quantitate reverse-transcriptase polymerase chain reaction; prostaglandins using liquid chromatography tandem mass spectrometry and cyclooxygenase activity using spectrophotometry. UVB enhances the percentage of apoptotic keratinocytes, which can be caused by the increased prostaglandin generation by cyclooxygenase-2, or/and induced cannabinoid receptor 1/2 (CB1/2) expression. AEA used alone intensifies apoptosis by affecting caspase expression, and in UVB-irradiated keratinocytes, cyclooxygenase-2 activity is increased, while CBD acts as a cytoprotective when used with or without UVB. After COX-2 inhibition, UVB-induced changes are partially ameliorated, when anandamide becomes an anti-apoptotic agent. It can be caused by observed reduced generation of anandamide pro-apoptotic derivative prostaglandin-ethanolamide by COX. Therefore, products of cyclooxygenase-dependent lipid metabolism seem to play an important role in the modulation of UVB-induced apoptosis by cannabinoids, which is particularly significant in case of AEA as inhibition of cyclooxygenase reduces the generation of pro-apoptotic lipid mediators and thus prevents apoptosis.

Cannabinoids orchestrate cross-talk between cancer cells and endothelial cells in colorectal cancer

Medical marijuana has been approved by the FDA for treating chemotherapy-induced nausea and vomiting. However, less is known about its direct effects on tumor cells and the tumor microenvironment. In this study, RNA-sequencing datasets in the NCBI GEO repository were first analyzed; upregulation of cannabinoid receptors was observed in both primary and metastatic colorectal cancer (CRC) tumor tissues. An increase of cannabinoid receptors was also found in patients with CRC, azoxymethane/dextran sulfate sodium-induced CRC and CRC metastatic mouse models. Δ⁹-Tetrahydrocannabinol (Δ⁹-THC)-induced tumor progression in both primary and metastatic mouse models and also increased angiogenesis. A human growth factor antibody array indicated that Δ⁹-THC promoted the secretion of angiogenic growth factors in CRC, leading to the induction of tube formation and migration in human-induced pluripotent stem cell-derived vascular endothelial cells. The nuclear translocation of STAT1 played important roles in Δ⁹-THC-induced angiogenesis and tumor progression. Pharmacological treatment with STAT1 antagonist or abrogation of STAT1 with CRISPR/Cas9-based strategy rescued those effects of Δ⁹-THC in CRC. This study demonstrates that marijuana might increase the risk of CRC progression and that inhibition of STAT1 is a potential strategy for attenuating these side effects.

Cannabinoids as anticancer drugs: current status of preclinical research

Drugs that target the endocannabinoid system are of interest as pharmacological options to combat cancer and to improve the life quality of cancer patients. From this perspective, cannabinoid compounds have been successfully tested as a systemic therapeutic option in a number of preclinical models over the past decades. As a result of these efforts, a large body of data suggests that the anticancer effects of cannabinoids are exerted at multiple levels of tumour progression via different signal transduction mechanisms. Accordingly, there is considerable evidence for cannabinoid-mediated inhibition of tumour cell proliferation, tumour invasion and metastasis, angiogenesis and chemoresistance, as well as induction of apoptosis and autophagy. Further studies showed that cannabinoids could be potential combination partners for established chemotherapeutic agents or other therapeutic interventions in cancer treatment. Research in recent years has yielded several compounds that exert promising effects on tumour cells and tissues in addition to the psychoactive Δ9-tetrahydrocannabinol, such as the non-psychoactive phytocannabinoid cannabidiol and inhibitors of endocannabinoid degradation. This review provides an up-to-date overview of the potential of cannabinoids as inhibitors of tumour growth and spread as demonstrated in preclinical studies.

Chronic Administration of Cannabinoid Receptor 2 Agonist (JWH-133) Increases Ectopic Ovarian Tumor Growth and Endocannabinoids (Anandamide and 2-Arachidonoyl Glycerol) Levels in Immunocompromised SCID Female Mice

Cannabinoid-based therapies are increasingly being used by cancer patients to treat chemotherapy-induced nausea and vomiting. Recently, cannabinoids have gained increased attention for their effects on cancer growth. Indeed, the effect of CB₂ (JWH-015, JWH-133) agonists on breast cancer models have shown to reduce the size of breast cancer tumors. However, these studies assessing breast cancer progression were using CB₂ agonist administered early into the cancer progression therefore assessing their effects on already established tumors is a critical need. In our study, we evaluate tumor growth using an ectopic xenograft ovarian (SKOV-3 and OVCAR-5) cancer model. The impact of chronic (30 days) administration of CB₂ (JWH-133) agonist will be evaluated and started on 30 days of ectopic ovarian tumors. We will then evaluate and determine the mechanisms involved in ovarian cancer tumor growth by measuring levels of anandamide and 2-arachidonoyl glycerol as well as protein levels of CB₁, CB₂, ERα, ERβ, GPER, TNFα, IL-1β and IL-6 in ovarian and tumor tissues. Our results demonstrate a significant increase in ectopic ovarian tumor growth following chronic administration of JWH-133. Ovarian cancer tumor tissues chronically (30 days) treated with JWH-133 in comparison to vehicle treated groups showed an increase in endocannabinoid (AEA and 2-AG) and protein (CB₂ and TNFα) levels with a decrease in GPER protein levels. Interestingly, our study emphasizes the importance of studying the impact of cannabinoid compounds on already established tumors to improve our understanding of cannabinoid-based therapies and, therefore better address clinical needs in cancer patients.

Cannabinoids, their cellular receptors, and effects on the invasive phenotype of carcinoma and metastasis

BACKGROUND

The morbidity and mortality of cancer are significantly impacted by the invasive and metastatic potential of particular subgroups of malignant cells within a tumor. The particular pre-metastatic properties of cancerous cells are thus a critical target for novel therapeutics in the oncology field. Cannabinoid molecules have been investigated in recent years in the context of invasion and metastasis of various malignancies, with varying effects reported in the literature.

RECENT FINDINGS

There was substantial variability in the findings reported by the literature of the effects of cannabinoid molecules on cancer cell invasion and metastasis. These effects varied depending on which ligand and which of the CB1, CB2, or GPR55 receptors were investigated. These findings suggest a role for the phenomenon of biased signaling in explaining the diversity of effects of cannabinoid molecules on cancer cell invasion.

CONCLUSION

While substantially more investigation is required into the effects of cannabinoid molecules on cancer cell invasion and metastasis, we describe in this review the significant diversity in the responses of cancer cells to cannabinoid molecules in terms of their invasive and metastatic capacities.

Cannabinoid receptors promote chronic intermittent hypoxia-induced breast cancer metastasis via IGF-1R/AKT/GSK-3β

The progression of breast cancer is closely related to obstructive sleep apnea-hypopnea syndrome (OSAHS). Low concentrations of cannabinoids promote tumor proliferation. However, the role of cannabinoid receptors (CBs) in chronic intermittent hypoxia (CIH)-induced breast cancer has not been reported. The migration and invasion of breast cancer cell lines (MCF-7 and T47D) were measured by scratch assay and transwell assay. Gene and protein expressions were analyzed by qPCR and western blotting. Tumor xenograft mice model were established to evaluate the function of CBs. We observed that chronic hypoxia (CH) and CIH increased CBs expression and promoted migration and invasion in breast cancer. Mice grafted with MCF-7 exhibited obvious tumor growth, angiogenesis, and lung metastasis in CIH compared with CH and control. In addition, CIH induced CBs expression, which subsequently activated insulin-like growth factor-1 receptor (IGF-1R)/AKT/glycogen synthase kinase-3β (GSK-3β) axis. Knockdown of CBs alleviated CIH-induced migration and invasion of breast cancer in vitro. Furthermore, CIH exaggerated the malignancy of breast cancer and silencing of CBs suppressed tumor growth and metastasis in vivo. Our study contributed to understanding the role of CIH in breast cancer development modulation.

Cannabinoid Cancer Biology and Prevention

Plant-based, synthetic, and endogenous cannabinoids have been shown to control a diverse array of biological processes, including regulation of cell fate across cancers. Their promise as broad-based antitumor agents in preclinical models has led to the initiation of pilot clinical trials. Session 5 of the National Cancer Institute's Cannabis, Cannabinoids and Cancer Research Symposium provides an overview of this research topic. Overall, the presentations highlight cannabinoid signal transduction and specific molecular mechanisms underlying cannabinoid antitumor activity. They also demonstrate the broad-based antitumor activity of the plant-based, synthetic, and endogenous cannabinoid compounds. Importantly, evidence is presented demonstrating when cannabinoids may be contraindicated as a treatment for cancer, as in the case of human papilloma virus-meditated oropharynx cancer or potentially other p38 MAPK pathway-driven cancers. Finally, it is discussed that a key to advancing cannabinoids into the clinic is to conduct well-designed, large-scale clinical trials to determine whether cannabinoids are effective antitumor agents in cancer patients.

Disease-Dependent Antiapoptotic Effects of Cannabidiol for Keratinocytes Observed upon UV Irradiation

Although apoptosis of keratinocytes has been relatively well studied, there is a lack of information comparing potentially proapoptotic treatments for healthy and diseased skin cells. Psoriasis is a chronic autoimmune-mediated skin disease manifested by patches of hyperproliferative keratinocytes that do not undergo apoptosis. UVB phototherapy is commonly used to treat psoriasis, although this has undesirable side effects, and is often combined with anti-inflammatory compounds. The aim of this study was to analyze if cannabidiol (CBD), a phytocannabinoid that has anti-inflammatory and antioxidant properties, may modify the proapoptotic effects of UVB irradiation in vitro by influencing apoptotic signaling pathways in donor psoriatic and healthy human keratinocytes obtained from the skin of five volunteers in each group. While CBD alone did not have any major effects on keratinocytes, the UVB treatment activated the extrinsic apoptotic pathway, with enhanced caspase 8 expression in both healthy and psoriatic keratinocytes. However, endoplasmic reticulum (ER) stress, characterized by increased expression of caspase 2, was observed in psoriatic cells after UVB irradiation. Furthermore, decreased p-AKT expression combined with increased 15-d-PGJ₂ level and p-p38 expression was observed in psoriatic keratinocytes, which may promote both apoptosis and necrosis. Application of CBD partially attenuated these effects of UVB irradiation both in healthy and psoriatic keratinocytes, reducing the levels of 15-d-PGJ₂, p-p38 and caspase 8 while increasing Bcl2 expression. However, CBD increased p-AKT only in UVB-treated healthy cells. Therefore, the reduction of apoptotic signaling pathways by CBD, observed mainly in healthy keratinocytes, suggests the need for further research into the possible beneficial effects of CBD.

Pharmacological Properties, Therapeutic Potential and Molecular Mechanisms of JWH133, a CB2 Receptor-Selective Agonist

The endocannabinoid system has attracted attention as a pharmacological target for several pathological conditions. Cannabinoid (CB2)-selective agonists have been the focus of pharmacological studies because modulation of the CB2 receptor (CB2R) can be useful in the treatment of pain, inflammation, arthritis, addiction, and cancer among other possible therapeutic applications while circumventing CNS-related adverse effects. Increasing number of evidences from different independent preclinical studies have suggested new perspectives on the involvement of CB2R signaling in inflammation, infection and immunity, thus play important role in cancer, cardiovascular, renal, hepatic and metabolic diseases. JWH133 is a synthetic agonist with high CB2R selectivity and showed to exert CB2R mediated antioxidant, anti-inflammatory, anticancer, cardioprotective, hepatoprotective, gastroprotective, nephroprotective, and immunomodulatory activities. Cumulative evidences suggest that JWH133 protects against hepatic injury, renal injury, cardiotoxicity, fibrosis, rheumatoid arthritis, and cancer as well as against oxidative damage and inflammation, inhibits fibrosis and apoptosis, and acts as an immunosuppressant. This review provides a comprehensive overview of the polypharmacological properties and therapeutic potential of JWH133. This review also presents molecular mechanism and signaling pathways of JWH133 under various pathological conditions except neurological diseases. Based on the available data, this review proposes the possibilities of developing JWH133 as a promising therapeutic agent; however, further safety and toxicity studies in preclinical studies and clinical trials in humans are warranted.

Cannabinoids pharmacological effects are beyond the palliative effects: CB2 cannabinoid receptor agonist induced cytotoxicity and apoptosis in human colorectal cancer cells (HT-29)

Colorectal cancer (CRC) is between the top three occurring cancers worldwide. The anticancer effects of Cannabinoid receptor 2 (CB₂) agonist (GW833972A) in the presence and absence of its inverse agonist (SR144528) on Human colorectal adenocarcinoma cells (HT-29) was investigated. Following cell viability assays on HT-29 and HFF cells, the molecular mechanism(s) of cytotoxicity and apoptotic pathways of cell death were analyzed. The anticancer effects of CB₂ agonist were measured with tumor cell migration and colony-forming assays. Real-time PCR and Western blotting techniques were used to examine any alterations in the expression of apoptotic genes. A concentration and time-dependent cytotoxicity of CB₂ agonist with IC50 value of 24.92 ± 6.99 μM was obtained. The rate of lipid peroxidation was elevated, while the TNF-α concentration was declined, significantly (p < 0.05). CB₂ agonist (50 μM) reduced the colony-forming capability by 83% and tumor cell migration by 50%. Apoptotic effects of CB₂ agonist were revealed with the increase of apoptotic cells in Acridine orange/Ethidium bromide staining, clear DNA fragmentation, pro-apoptotic genes and proteins upregulation (Caspase-3 and p53), and significant downregulation of anti-apoptotic Bcl-2. All assessments demonstrated that CB₂ agonist-induced effects were reversed by CB₂ inverse agonist. These data suggest that CB₂ agonists at micro-molar concentrations might be considered in the CRC treatment, and their effectiveness attributes to the apoptosis induction via upregulation of caspase-3 and p53 and downregulation of Bcl-2.

Cannabinoid Receptor Type-2 in B Cells Is Associated with Tumor Immunity in Melanoma

Simple Summary

In this study we investigated the role of cannabinoid receptor 2 (CB2R) on immune cells in melanoma and found significantly improved overall survival in patients with high intra-tumoral CB2R gene expression. In human melanoma, CB2R is predominantly expressed in B cells, as shown using a previously published single-cell RNA sequencing (scRNA-seq) dataset and by performing RNAscope. In a murine melanoma model, tumor growth was enhanced in CB2R-deficient mice. In-depth analysis of tumor-infiltrating lymphocytes using scRNA-seq showed less differentiated B cells in CB2R-deficient tumors, favoring the induction of regulatory T cells (T_reg) and an immunosuppressive tumor microenvironment. Taken together, these data indicate a central role of CB2R on B cells in regulating tumor immunity. These results contribute to the understanding of the role of CB2R in tumor immunity and facilitate the development of new CB2R-targeted anti-cancer drugs.

Abstract

Agents targeting the endocannabinoid system (ECS) have gained attention as potential cancer treatments. Given recent evidence that cannabinoid receptor 2 (CB2R) regulates lymphocyte development and inflammation, we performed studies on CB2R in the immune response against melanoma. Analysis of The Cancer Genome Atlas (TCGA) data revealed a strong positive correlation between CB2R expression and survival, as well as B cell infiltration in human melanoma. In a murine melanoma model, CB2R expression reduced the growth of melanoma as well as the B cell frequencies in the tumor microenvironment (TME), compared to CB2R-deficient mice. In depth analysis of tumor-infiltrating B cells using single-cell RNA sequencing suggested a less differentiated phenotype in tumors from Cb2r^−/− mice. Thus, in this study, we demonstrate for the first time a protective, B cell-mediated role of CB2R in melanoma. This gained insight might assist in the development of novel, CB2R-targeted cancer therapies.

Functional Fine-Tuning of Metabolic Pathways by the Endocannabinoid System-Implications for Health and Disease

The endocannabinoid system (ECS) employs a huge network of molecules (receptors, ligands, and enzymatic machinery molecules) whose interactions with other cellular networks have still not been fully elucidated. Endogenous cannabinoids are molecules with the primary function of control of multiple metabolic pathways. Maintenance of tissue and cellular homeostasis by functional fine-tuning of essential metabolic pathways is one of the key characteristics of the ECS. It is implicated in a variety of physiological and pathological states and an attractive pharmacological target yet to reach its full potential. This review will focus on the involvement of ECS in glucose and lipid metabolism, food intake regulation, immune homeostasis, respiratory health, inflammation, cancer and other physiological and pathological states will be substantiated using freely available data from open-access databases, experimental data and literature review. Future directions should envision capturing its diversity and exploiting pharmacological options beyond the classical ECS suspects (exogenous cannabinoids and cannabinoid receptor monomers) as signaling through cannabinoid receptor heteromers offers new possibilities for different biochemical outcomes in the cell.

Stability Study of Cannabidiol in the Form of Solid Powder and Sunflower Oil Solution

Stability studies represent an essential component of pharmaceutical development, enabling critical evaluation of the therapeutic potential of an active pharmaceutical ingredient (API) or a final pharmaceutical product under the influence of various environmental factors. The aim of the present study was to investigate the chemical stability of cannabidiol (CBD) in the form of a solid powder (hereinafter referred to as CBD powder) and also dissolved in sunflower oil. We performed stress studies in accordance with the International Conference on Harmonization (ICH) guidelines, where 5 mg of marketed CBD in the form of a solid powder and in form of oil solution were exposed for 7 and 14, 30, 60, 90, 180, 270, and 365 days to precisely defined temperature and humidity conditions, 25 °C ± 2 °C/60% RH ± 5% and 40 °C ± 2 °C/75% RH ± 5% in both open and closed vials in the dark. CBD powder was significantly more stable than CBD in oil solution. Such finding is important because CBD is often administered dissolved in oil matrix in practice due to very good bioavailability. Thus, the knowledge on admissible shelf time is of paramount importance.

The Interplay between Cancer Biology and the Endocannabinoid System-Significance for Cancer Risk, Prognosis and Response to Treatment

The various components of the endocannabinoid system (ECS), such as the cannabinoid receptors (CBRs), cannabinoid ligands, and the signalling network behind it, are implicated in several tumour-related states, both as favourable and unfavourable factors. This review analyses the ECS's complex involvement in the susceptibility to cancer, prognosis, and response to treatment, focusing on its relationship with cancer biology in selected solid cancers (breast, gastrointestinal, gynaecological, prostate cancer, thoracic, thyroid, CNS tumours, and melanoma). Changes in the expression and activation of CBRs, as well as their ability to form distinct functional heteromers affect the cell's tumourigenic potential and their signalling properties, leading to pharmacologically different outcomes. Thus, the same ECS component can exert both protective and pathogenic effects in different tumour subtypes, which are often pathologically driven by different biological factors. The use of endogenous and exogenous cannabinoids as anti-cancer agents, and the range of effects they might induce (cell death, regulation of angiogenesis, and invasion or anticancer immunity), depend in great deal on the tumour type and the specific ECS component that they target. Although an attractive target, the use of ECS components in anti-cancer treatment is still interlinked with many legal and ethical issues that need to be considered.

Modeling of the immune response in the pathogenesis of solid tumors and its prognostic significance

BACKGROUND

Tumor initiation and subsequent progression are usually long-term processes, spread over time and conditioned by diverse aspects. Many cancers develop on the basis of chronic inflammation; however, despite dozens of years of research, little is known about the factors triggering neoplastic transformation under these conditions. Molecular characterization of both pathogenetic states, i.e., similarities and differences between chronic inflammation and cancer, is also poorly defined. The secretory activity of tumor cells may change the immunophenotype of immune cells and modify the extracellular microenvironment, which allows the bypass of host defense mechanisms and seems to have diagnostic and prognostic value. The phenomenon of immunosuppression is also present during chronic inflammation, and the development of cancer, due to its duration, predisposes patients to the promotion of chronic inflammation. The aim of our work was to discuss the above issues based on the latest scientific insights. A theoretical mechanism of cancer immunosuppression is also proposed.

CONCLUSIONS

Development of solid tumors may occur both during acute and chronic phases of inflammation. Differences in the regulation of immune responses between precancerous states and the cancers resulting from them emphasize the importance of immunosuppressive factors in oncogenesis. Cancer cells may, through their secretory activity and extracellular transport mechanisms, enhance deterioration of the immune system which, in turn, may have prognostic implications.

Lipids and cancer: Emerging roles in pathogenesis, diagnosis and therapeutic intervention

With the advent of effective tools to study lipids, including mass spectrometry-based lipidomics, lipids are emerging as central players in cancer biology. Lipids function as essential building blocks for membranes, serve as fuel to drive energy-demanding processes and play a key role as signaling molecules and as regulators of numerous cellular functions. Not unexpectedly, cancer cells, as well as other cell types in the tumor microenvironment, exploit various ways to acquire lipids and extensively rewire their metabolism as part of a plastic and context-dependent metabolic reprogramming that is driven by both oncogenic and environmental cues. The resulting changes in the fate and composition of lipids help cancer cells to thrive in a changing microenvironment by supporting key oncogenic functions and cancer hallmarks, including cellular energetics, promoting feedforward oncogenic signaling, resisting oxidative and other stresses, regulating intercellular communication and immune responses. Supported by the close connection between altered lipid metabolism and the pathogenic process, specific lipid profiles are emerging as unique disease biomarkers, with diagnostic, prognostic and predictive potential. Multiple preclinical studies illustrate the translational promise of exploiting lipid metabolism in cancer, and critically, have shown context dependent actionable vulnerabilities that can be rationally targeted, particularly in combinatorial approaches. Moreover, lipids themselves can be used as membrane disrupting agents or as key components of nanocarriers of various therapeutics. With a number of preclinical compounds and strategies that are approaching clinical trials, we are at the doorstep of exploiting a hitherto underappreciated hallmark of cancer and promising target in the oncologist's strategy to combat cancer.

Cannabinoids Promote Progression of HPV-Positive Head and Neck Squamous Cell Carcinoma via p38 MAPK Activation

PURPOSE

Human papillomavirus (HPV)-related head and neck squamous cell carcinoma (HNSCC) is associated with daily marijuana use and is also increasing in parallel with increased marijuana use in the United States. Our study is designed to define the interaction between cannabinoids and HPV-positive HNSCC.

EXPERIMENTAL DESIGN

The expression of cannabinoid receptors CNR1 and CNR2 was analyzed using The Cancer Genome Atlas (TCGA) HNSCC data. We used agonists, antagonists, siRNAs, or shRNA-based models to explore the roles of CNR1 and CNR2 in HPV-positive HNSCC cell lines and animal models. Cannabinoid downstream pathways involved were determined by Western blotting and analyzed in a primary HPV HNSCC cohort with single-sample gene set enrichment analysis (ssGSEA) and the OncoGenome Positioning System (Onco-GPS).

RESULTS

In TCGA cohort, the expression of CNR1 and CNR2 was elevated in HPV-positive HNSCC compared with HPV-negative HNSCC, and knockdown of CNR1/CNR2 expression inhibited proliferation in HPV-positive HNSCC cell lines. Specific CNR1 and CNR2 activation as well as nonselective cannabinoid receptor activation in cell lines and animal models promoted cell growth, migration, and inhibited apoptosis through p38 MAPK pathway activation. CNR1/CNR2 antagonists suppressed cell proliferation and migration and induced apoptosis. Using whole-genome expression analysis in a primary HPV HNSCC cohort, we identified specific p38 MAPK pathway activation signature in tumors from HPV HNSCC patients with objective measurement of concurrent cannabinoid exposure.

CONCLUSIONS

Cannabinoids can promote progression of HPV-positive HNSCC through p38 MAPK pathway activation.

Cannabinoid receptor 2 agonist promotes parameters implicated in mucosal healing in patients with inflammatory bowel disease

BACKGROUND

Cannabis benefits patients with inflammatory bowel disease (IBD). Cannabinoid receptors are expressed in gut immune cells and in epithelial cells of inflamed guts. Mucosal healing (MH) requires epithelial layer restoration.

OBJECTIVE

To analyze the effects of CB2 agonist on parameters implicated in gut inflammation and MH.

METHODS

Mucosal samples from areas of inflamed/uninflamed colon from 16 patients with IBD were cultured without/with cannabinoid receptor 2 (CB2) agonist (JWH-133, 10 µM, 6 hours (hr)), and analyzed for epithelial/stromal cell proliferation, apoptosis (secretome matrix metalloproteinase 9 (MMP9) activity, which impairs epithelial permeability) and interleukin-8 (IL-8) levels (n = 5-9). In addition, Caco-2 (colon carcinoma epithelial cells) were cultured with biopsy secretomes (48 hr), and analyzed for phenotype and protein markers of proliferation (proliferating cell nuclear antigen), autophagy (LC3IIB) and permeability (Zonula occludens-1) (n = 4-6).

RESULTS

Uninflamed tissue had higher epithelial proliferation (Ki67: 50%↑, p < 0.05), and reduced secretome MMP9 activity and IL-8 levels (>50%↓, p < 0.05) compared to inflamed tissue. Treatment with CB2 agonist had no effect on epithelial apoptosis, but increased epithelial Ki67 expression (25%), and reduced secretome MMP9 and IL-8 levels in inflamed biopsies. Secretomes of CB2-treated biopsies increased Caco-2 number, migration, proliferating cell nuclear antigen and LC3IIB expression (all, p < 0.05), but had no effect on ZO-1.

CONCLUSION

Using ex vivo and in vitro human models, we demonstrated that manipulating the cannabinoid system affects colon cells and secretome characteristics that facilitate MH in IBD.

Reduced expression of microRNA-139-5p in hepatocellular carcinoma results in a poor outcome: An exploration the roles of microRNA-139-5p in tumorigenesis, advancement and prognosis at the molecular biological level using an integrated meta-analysis and bioinformatic investigation

Hepatocellular carcinoma (HCC) is generally considered one of the most common gastrointestinal malignant tumors, characterized by high invasiveness and metastatic rate, as well as insidious onset. A relationship between carcinogenicity and aberrant microRNA-139-5p (miR-139-5p) expression has been identified in multiple tumors while the specific molecular mechanisms of miR-139-5p in HCC have not yet been thoroughly elucidated. A meta-analysis of available data from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus, ArrayExpress and Oncomine databases, as well as the published literature, was comprehensively conducted with the aim of examining the impact of miR-139-5p expression on HCC. Additionally, predicted downstream target genes were confirmed using a series of bioinformatics tools. Moreover, a correlative biological analysis was performed to ascertain the precise function of miR-139-5p in HCC. The results revealed that the expression of miR-139-5p was noticeably lower in HCC compared with non-tumor liver tissues according to the pooled standard mean difference, which was -0.84 [95% confidence interval (CI): -1.36 to -0.32; P<0.001]. Furthermore, associations were detected between miR-139-5p expression and certain clinicopathological characteristics of TCGA samples, including tumor grade, pathological stage and T stage. Moreover, the pooled hazard ratio (HR) for overall survival (HR=1.37; 95% CI: 1.07-1.76; P=0.001) indicated that decreased miR-139-5p expression was a risk factor for adverse outcomes. Additionally, 382 intersecting genes regulated by miR-139-5p were obtained and assembled in signaling pathways, including 'transcription factor activity, sequence-specific DNA binding', 'pathways in cancer' and 'Ras signaling pathway'. Notably, four targeted genes that were focused in 'pathways in cancer' were identified as hub genes and immunohistochemical staining of the proteins encoded by these four hub genes in liver tissues, explored using the Human Protein Atlas database, confirmed their expression patterns in HCC and normal liver tissues Findings of the present study suggest that reduced miR-139-5p expression is capable of accelerating tumor progression and is associated with a poor clinical outcome by modulating the expression of downstream target genes involved in tumor-associated signaling pathways.

Genetic landscape of prognostic value in pancreatic ductal adenocarcinoma microenvironment

Background

The prognosis of pancreatic ductal adenocarcinoma (PDAC) remains dismally poor and is widely considered as an intricate genetic disorder. The mutational landscape of PDAC may directly reflect cancer immunogenicity and dictate the extent and phenotype of immune cell infiltration. In adverse, the microenvironment may also effect the gene expression of cancer cells, which is associated with clinical prognosis. Thus, it is crucial to identify genomic alterations in PDAC microenvironment and its impacts on clinical prognosis.

Methods

The gene expression profiles, mutation data and clinical information of 179 pancreatic cancer patients with an initial pathologic diagnosis ranging from 2001 to 2013 were retrieved from The Cancer Genome Atlas (TCGA) database. The MAlignant Tumor tissues using Expression data (ESTIMATE) algorithm for calculating immune scores and stromal scores and Tumor IMmune Estimation Resource (TIMER) resource for cell infiltrations were applied in this study.

Results

The average immune score or stromal score of PDAC subtype was significantly higher than that of other specific subtypes. KRAS mutant cases had significantly lower immune scores (P=0.001) and stromal scores (P=0.007), in concert with lower immune scores in TP53 mutant cases (P=0.030). However, no significant difference was found in SMAD4 and CDKN2A mutations. In the cohort OS/RFS, the infiltration levels of CD8+ T cells, B cells, Macrophages, Neutrophils and DCs in high stromal score group were higher than those in the low score group (all P<0.001), as well as in immune score groups except for Macrophages in the cohort RFS. In the cohort OS/RFS, 317/379 upregulated genes and 9/6 downregulated genes were observed in the high immune score group, while 227/205 upregulated genes and 17/6 downregulated genes in the high stromal score group. With the analysis for prognostic value of DEGs, 82 and 58 DEGs respectively in the high immune and stromal score group were verified to be significantly associated with better OS (P<0.05), while 53 and 17 DEGs respectively with longer RFS (P<0.05). Functional enrichment analysis showed genes of prognostic values were significantly related to immune response.

Conclusions

A list of genes with prognostic value in PDAC microenvironment were obtained from functional enrichment analysis based on immune and stromal scores, which indicates a series of potential auxiliary prognostic biomarkers for PDAC are available. Further research on these genes may be valuable and helpful to understand the crosstalk between tumor and microenvironment, new immune evasion mechanisms and underlying novel therapeutic targets in an integrated manner.

The oncogenic role of CB2 in the progression of non-small-cell lung cancer

BACKGROUND

Several studies have verified the important role of cannabinoid and cannabinoid receptor agonists in tumor progression. However, little is known about the precise role of CB2 expression level in the progression of non-small-cell lung cancer (NSCLC).

METHODS

The expression of CB2 in NSCLC tissues and corresponding paracancerous tissues was examined using immunohistochemical staining assay. The expression of CB2 was silenced by siRNA interference and loss-of-function assays were performed to investigate the biological function of CB2 in the proliferation, migration, invasion, and apoptosis of NSCLC cells. The expression of related proteins was detected using western blot analysis.

RESULTS

In this study, we observed that CB2 was up-regulated in NSCLC tissues and the up-regulation was correlated with tumor size and advanced NSCLC pathological grading. Moreover, compared with the control group, silencing of CB2 decreased the proliferation, migration and invasion abilities of A549 and H1299 cells, and induced apoptosis by regulation of Bcl-2/Bax axis and active Caspase3. Furthermore, CB2 knockdown inactivated the Akt/mTOR/P70S6K pathway by decreasing the level of p-Akt, p-mTOR and expression of P70S6K in A549 and H1299 cells.

CONCLUSION

Our data suggested that targeting CB2 may inhibit the growth and survival of NSCLC cells, which the Akt/mTOR/P70S6K pathway may be involved in. These results confer the pro-oncogenic role of CB2 in the progression of NSCLC, thus improving our understanding of CB2 in tumor progression.

Cancer-associated fibroblasts modify lung cancer metabolism involving ROS and TGF-β signaling

Lung cancer is a major public health problem due to its high incidence and mortality rate. The altered metabolism in lung cancer is key for the diagnosis and has implications on both, the prognosis and the response to treatments. Although Cancer-associated fibroblasts (CAFs) are one of the major components of the tumor microenvironment, little is known about their role in lung cancer metabolism. We studied tumor biopsies from a cohort of 12 stage IIIA lung adenocarcinoma patients and saw a positive correlation between the grade of fibrosis and the glycolysis phenotype (Low PGC-1α and High GAPDH/MT-CO1 ratio mRNA levels). These results were confirmed and extended to other metabolism-related genes through the in silico data analysis from 73 stage IIIA lung adenocarcinoma patients available in TCGA. Interestingly, these relationships are not observed with the CAFs marker α-SMA in both cohorts. To characterize the mechanism, in vitro co-culture studies were carried out using two NSCLC cell lines (A549 and H1299 cells) and two different fibroblast cell lines. Our results confirm that a metabolic reprogramming involving ROS and TGF-β signaling occurs in lung cancer cells and fibroblasts independently of α-SMA induction. Under co-culture conditions, Cancer-Associated fibroblasts increase their glycolytic ability. On the other hand, tumor cells increase their mitochondrial function. Moreover, the differential capability among tumor cells to induce this metabolic shift and also the role of the basal fibroblasts Oxphos Phosphorylation (OXPHOS) function modifying this phenomenon could have implications on both, the diagnosis and prognosis of patients. Further knowledge in the mechanism involved may allow the development of new therapies.

Synthetic Cannabinoid Activity Against Colorectal Cancer Cells

Introduction: Colorectal cancer (CRC) is a leading cause of cancer-related deaths worldwide, and new therapeutic strategies are still required. Here we screened a synthetic cannabinoid library to identify compounds that uniformly reduce the viability of seven CRC cell lines.

Material and Methods: Seven distinct CRC cell lines were treated with 10 μM cannabinoid compounds (from a library of 370 molecules) for 48 h, and cell viability was subsequently measured with MTS assay. Dose–response curves were conducted for compounds that were found to reproducibly reduce cell viability of one or more cell lines.

Results: We identified 10 compounds from the library that were able to reduce cell viability of CRC cell lines (with an IC₅₀ ≤ 30 μM). Of these compounds, seven were specific for CRC cells, and six were effective in all CRC cell lines tested. Treatment with traditional phytocannabinoids (THC or CBD) was either ineffective or much less potent and only partially efficacious. Treatment with antagonists for the known cannabinoid receptors (alone or in combination) failed to block the activity of the most potent of identified compounds.

Conclusion: We identified three families of cannabinoid compounds that reduce CRC cell viability through a noncanonical receptor mechanism. Future modification of these compounds may lead to the development of novel therapies to treat this disease.

Promising neuroprotective effects of β-caryophyllene against LPS-induced oligodendrocyte toxicity: A mechanistic study

Myelin loss subsequent to oligodendrocyte death has been reported in a variety of myelin-associated disorders such as multiple sclerosis (MS). Lipopolysaccharide (LPS) has been shown to elicit cellular responses in the central nervous system (CNS) and trigger immune infiltrates and glial cells to release a variety of inflammatory cytokines and mediators. LPS-induced oligodendrocytes toxicity may be chosen as an efficient model to evaluate the role of oligodendrocytes in neuroprotective activities of compounds. β-Caryophyllene (BCP) is a selective type 2 cannabinoid (CB₂) receptor agonist. However, the mechanisms underlying the anti-inflammatory effects of BCP are not completely understood. On this basis, we aimed to investigate the protective effects of a wide range of BCP concentrations against LPS-induced toxicity in a proliferative oligodendrocyte cell line (OLN-93) and evaluate the possible correlation between BCP concentration and selective modulation of CB₂, Nrf2, sphingomyelinase (SMase) and peroxisome proliferator-activated receptors (PPAR)-γ signaling pathways. We found that LPS significantly increases the levels of reactive oxygen species (ROS), nitric oxide (NO) metabolite and tumor necrosis factor (TNF)-α production while decreases the level of GSH. BCP could prevent LPS-induced cytotoxicity and excessive production of NO, ROS, and TNF-α. Also, we demonstrated that BCP's protective effects against LPS-induced oligodendrocytes toxicity were mediated via the CB₂ receptor through different pathways including Nrf2/HO-1/anti-oxidant axis, and PPAR-γ, at low (0.2 and 1 µM), and high (10-50 µM) concentrations, respectively. Additionally, we observed that the addition of SMase inhibitors imipramine (IMP) and fluoxetine (FLX) synergistically increased the protective effects of BCP. Finally, BCP at low concentrations exerted promising protective effects that could be considered for the treatment of neurodegenerative disorders such as MS. However, more studies using other models of neurodegenerative diseases should be undertaken to assess different parameters such as the activity or expression of SMase.

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.

Monoacylglycerol lipase regulates cannabinoid receptor 2-dependent macrophage activation and cancer progression

Metabolic reprogramming greatly contributes to the regulation of macrophage activation. However, the mechanism of lipid accumulation and the corresponding function in tumor-associated macrophages (TAMs) remain unclear. With primary investigation in colon cancer and confirmation in other cancer models, here we determine that deficiency of monoacylglycerol lipase (MGLL) results in lipid overload in TAMs. Functionally, macrophage MGLL inhibits CB2 cannabinoid receptor-dependent tumor progression in inoculated and genetic cancer models. Mechanistically, MGLL deficiency promotes CB2/TLR4-dependent macrophage activation, which further suppresses the function of tumor-associated CD8+ T cells. Treatment with CB2 antagonists delays tumor progression in inoculated and genetic cancer models. Finally, we verify that expression of macrophage MGLL is decreased in cancer tissues and positively correlated with the survival of cancer patients. Taken together, our findings identify MGLL as a switch for CB2/TLR4-dependent macrophage activation and provide potential targets for cancer therapy.

Medical Cannabis and Cannabinoids: An Option for the Treatment of Inflammatory Bowel Disease and Cancer of the Colon?

In the past few years, we have witnessed a surge of new reports dealing with the role of cannabinoids, synthetic as well as herbal, in the mechanisms of inflammation and carcinogenesis. However, despite the wealth of in vitro data and anecdotal reports, evidence that cannabinoids could act as beneficial drugs in inflammatory bowel disease (IBD) or in neoplastic development of the human gastrointestinal tract is lacking. Some insight into the effects of medical Cannabis (usually meaning dried flowers) and cannabinoids in IBD has been gained through questionnaires and small pilot studies. As to colorectal cancer, only preclinical data are available. Currently, Δ⁹-tetrahydrocannabinol (THC) and its synthetic forms, dronabinol and nabilone, are used as an add-on treatment to alleviate chronic pain and spasticity in multiple sclerosis patients as well as chemotherapy-induced nausea. The use of medical Cannabis is authorized only in a limited number of countries. None of the mentioned substances are currently indicated for IBD. This review is an update of our knowledge on the role of cannabinoids in intestinal inflammation and carcinogenesis and a discussion on their potential therapeutic use.

miRNA-29a inhibits colon cancer growth by regulation of the PTEN/Akt/GSK3β and Wnt/β-catenin signaling pathways

In the present study, the effects of microRNA-29a (miRNA-29a) on colon cancer cell viability and the molecular mechanisms underlying the effects were investigated. The expression of miRNA-29a in colon cancer serum samples was notably downregulated, compared with in the normal group. First, miRNA-29a mimic was used to increase the expression of miRNA-29a in HCT-116 cells. Furthermore, upregulation of miRNA-29a suppressed cell viability, increased lactate dehydrogenase levels and apoptosis, and promoted caspase-3/9 activities and B-cell lymphoma 2-associated X protein and phosphatase and tensin homolog (PTEN) protein expression in colon cancer cells. Furthermore, upregulation of miRNA-29a decreased phosphoinositide 3-kinase, phosphorylated (p)-protein kinase B (Akt) and p-glycogen synthase kinase 3β (GSK3β) protein expression and suppressed the Wnt/β-catenin signaling pathway in colon cancer cells. The results of the present study verified that the protective effects of miRNA-29a suppress the PTEN/Akt/GSK3β and Wnt/β-catenin signaling pathways in colon cancer.

The Trouble with CBD Oil

In just a few years, cannabidiol (CBD) has become immensely popular around the world. After initially being discovered as an effective self-medication for Dravet syndrome in children, CBD is now sold and used to treat a wide range of medical conditions and lifestyle diseases. The cannabinoid CBD, a non-psychoactive isomer of the more infamous tetrahydrocannabinol (THC), is available in a growing number of administration modes, but the most commonly known is CBD oil. There are currently dozens, if not hundreds, of producers and sellers of CBD oils active in the market, and their number is increasing rapidly. Those involved vary from individuals who prepare oils on a small scale for family and (Facebook) friends to compounding pharmacies, pharmaceutical companies, and licensed cannabis producers. Despite the growing availability of CBD, many uncertainties remain about the legality, quality, and safety of this new "miracle cure." As a result, CBD is under scrutiny on many levels, ranging from national health organizations and agricultural lobbyists to the WHO and FDA. The central question is whether CBD is simply a food supplement, an investigational new medicine, or even a narcotic. This overview paper looks into the known risks and issues related to the composition of CBD products, and makes recommendations for better regulatory control based on accurate labeling and more scientifically supported health claims. The intention of this paper is to create a better understanding of the benefits versus the risks of the current way CBD products are produced, used, and advertised.

Targeting Cannabinoid Signaling in the Immune System: "High"-ly Exciting Questions, Possibilities, and Challenges

It is well known that certain active ingredients of the plants of Cannabis genus, i.e., the "phytocannabinoids" [pCBs; e.g., (-)-trans-Δ⁹-tetrahydrocannabinol (THC), (-)-cannabidiol, etc.] can influence a wide array of biological processes, and the human body is able to produce endogenous analogs of these substances ["endocannabinoids" (eCB), e.g., arachidonoylethanolamine (anandamide, AEA), 2-arachidonoylglycerol (2-AG), etc.]. These ligands, together with multiple receptors (e.g., CB₁ and CB₂ cannabinoid receptors, etc.), and a complex enzyme and transporter apparatus involved in the synthesis and degradation of the ligands constitute the endocannabinoid system (ECS), a recently emerging regulator of several physiological processes. The ECS is widely expressed in the human body, including several members of the innate and adaptive immune system, where eCBs, as well as several pCBs were shown to deeply influence immune functions thereby regulating inflammation, autoimmunity, antitumor, as well as antipathogen immune responses, etc. Based on this knowledge, many in vitro and in vivo studies aimed at exploiting the putative therapeutic potential of cannabinoid signaling in inflammation-accompanied diseases (e.g., multiple sclerosis) or in organ transplantation, and to dissect the complex immunological effects of medical and "recreational" marijuana consumption. Thus, the objective of the current article is (i) to summarize the most recent findings of the field; (ii) to highlight the putative therapeutic potential of targeting cannabinoid signaling; (iii) to identify open questions and key challenges; and (iv) to suggest promising future directions for cannabinoid-based drug development.

Synergistic interaction of the cannabinoid and death receptor systems - a potential target for future cancer therapies?

Cannabinoid receptors have been shown to interact with other receptors, including tumor necrosis factor receptor superfamily (TNFRS) members, to induce cancer cell death. When cannabinoids and death-inducing ligands (including TNF-related apoptosis-inducing ligand) are administered together, they have been shown to synergize and demonstrate enhanced antitumor activity in vitro. Certain cannabinoid ligands have been shown to sensitize cancer cells and synergistically interact with members of the TNFRS, thus suggesting that the combination of cannabinoids with death receptor (DR) ligands induces additive or synergistic tumor cell death. This review summarizes recent findings on the interaction of the cannabinoid and DR systems and suggests possible clinical co-application of cannabinoids and DR ligands in the treatment of various malignancies.

Cannabinoid receptor 2 as a novel target for promotion of renal cell carcinoma prognosis and progression

PURPOSE

Renal cell carcinoma (RCC) is the most common malignancy of urogenital system, and patients with RCC may face a poor prognosis. However, limited curable therapeutic options are currently available. The aim of this study is to investigate the role of Cannabinoid receptor 2 (CB2) in RCC progression.

METHODS

Immunohistochemistry was to investigate the expression pattern of CB2 in 418 RCC tissues and explore its prognostic function in RCC patients. Furthermore, the role of used CB2 si-RNA knockdown and inhibited by AM630, a CB2 inverse agonist, on cell proliferation, migration, and cell cycle of RCC cell lines in vitro was also investigated.

RESULTS

We observed that CB2 was up-regulated in RCC tissues, and presented as an independent prognostic factor for overall survival of RCC patients and higher CB2 expression tends to have poor clinical outcomes in survival analyses. Moreover, we also observed that CB2, incorporated with pN stage, pathological grade, and recurrence or distant metastasis after surgery, could obviously enhance their prognostic accuracy in a predictive nomogram analysis. In addition, knockdown or inhibition by AM630 for the expression of CB2 in vitro could significantly decreased cell proliferation and migration, and obviously induced cell cycle arrest in G2/M of RCC cells.

CONCLUSIONS

CB2 expression is functionally related to cellular proliferation, migration, and cell cycle of RCC cells. Our data suggest that CB2 might be a potential therapeutic target for RCC.