Anandamide induces apoptosis in human cells via vanilloid receptors. Evidence for a protective role of cannabinoid receptors

Effects of Cannabidiol, ∆9-Tetrahydrocannabinol, and WIN 55-212-22 on the Viability of Canine and Human Non-Hodgkin Lymphoma Cell Lines

In our previous study, we demonstrated the impact of overexpression of CB1 and CB2 cannabinoid receptors and the inhibitory effect of endocannabinoids (2-arachidonoylglycerol (2-AG) and Anandamide (AEA)) on canine (Canis lupus familiaris) and human (Homo sapiens) non-Hodgkin lymphoma (NHL) cell lines' viability compared to cells treated with a vehicle. The purpose of this study was to demonstrate the anti-cancer effects of the phytocannabinoids, cannabidiol (CBD) and ∆9-tetrahydrocannabinol (THC), and the synthetic cannabinoid WIN 55-212-22 (WIN) in canine and human lymphoma cell lines and to compare their inhibitory effect to that of endocannabinoids. We used malignant canine B-cell lymphoma (BCL) (1771 and CLB-L1) and T-cell lymphoma (TCL) (CL-1) cell lines, and human BCL cell line (RAMOS). Our cell viability assay results demonstrated, compared to the controls, a biphasic effect (concentration range from 0.5 μM to 50 μM) with a significant reduction in cancer viability for both phytocannabinoids and the synthetic cannabinoid. However, the decrease in cell viability in the TCL CL-1 line was limited to CBD. The results of the biochemical analysis using the 1771 BCL cell line revealed a significant increase in markers of oxidative stress, inflammation, and apoptosis, and a decrease in markers of mitochondrial function in cells treated with the exogenous cannabinoids compared to the control. Based on the IC50 values, CBD was the most potent phytocannabinoid in reducing lymphoma cell viability in 1771, Ramos, and CL-1. Previously, we demonstrated the endocannabinoid AEA to be more potent than 2-AG. Our study suggests that future studies should use CBD and AEA for further cannabinoid testing as they might reduce tumor burden in malignant NHL of canines and humans.

Emerging Lipid Targets in Glioblastoma

GBM accounts for most of the fatal brain cancer cases, making it one of the deadliest tumor types. GBM is characterized by severe progression and poor prognosis with a short survival upon conventional chemo- and radiotherapy. In order to improve therapeutic efficiency, considerable efforts have been made to target various features of GBM. One of the targetable features of GBM is the rewired lipid metabolism that contributes to the tumor's aggressive growth and penetration into the surrounding brain tissue. Lipid reprogramming allows GBM to acquire survival, proliferation, and invasion benefits as well as supportive modulation of the tumor microenvironment. Several attempts have been made to find novel therapeutic approaches by exploiting the lipid metabolic reprogramming in GBM. In recent studies, various components of de novo lipogenesis, fatty acid oxidation, lipid uptake, and prostaglandin synthesis have been considered promising targets in GBM. Emerging data also suggest a significant role hence therapeutic potential of the endocannabinoid metabolic pathway in GBM. Here we review the lipid-related GBM characteristics in detail and highlight specific targets with their potential therapeutic use in novel antitumor approaches.

Investigating the impact of human blood metabolites on the Sepsis development and progression: a study utilizing two-sample Mendelian randomization

Background

Existing data suggests a potential link between human blood metabolites and sepsis, yet the precise cause-and-effect relationship remains elusive. By using a two-sample Mendelian randomization (MR) analysis, this study aims to establish a causal link between human blood metabolites and sepsis.

Methods

A two-sample MR analysis was employed to investigate the relationship between blood metabolites and sepsis. To assess the causal connection between sepsis and human blood metabolites, five different MR methods were employed, A variety of sensitivity analyses were conducted, including Cochrane's Q test, MR-Egger intercept test, MR-PRESSO and leave-one-out (LOO) analysis. In order to ensure the robustness of the causal association between exposure and outcome, the Bonferroni adjustment was employed. Additionally, we conducted analyses of the metabolic pathways of the identified metabolites using the Kyoto Encyclopedia of Genes and Genomes (KEGG) and the Small Molecule Pathway Database (SMPDB) database.

Results

The MR analysis revealed a total of 27 metabolites (16 known and 11 unknown) causally linked to the development and progression of sepsis. After applying the Bonferroni correction, 3-carboxy-4-methyl-5-propyl-2-furanpropanoate (CMPF) remained significant in relation to 28-day all-cause mortality in sepsis. By pathway enrichment analysis, we identified four significant metabolic pathways. Notably, the Alpha Linolenic Acid and Linoleic Acid metabolism pathway emerged as a pivotal contributor to the occurrence and progression of sepsis.

Conclusion

This study provides preliminary evidence of causal associations between human blood metabolites and sepsis, as ascertained by MR analysis. The findings offer valuable insights into the pathogenesis of sepsis and may provide insight into preventive and therapeutic approaches.

Endocannabinoids, Anandamide and 2-Arachidonoylglycerol, as Prognostic Markers of Sepsis Outcome and Complications

Background: One of the major challenges in improving sepsis care is early prediction of sepsis complications. The endocannabinoid system has been intensely studied in recent years; however, little is known about its role in sepsis in humans. This study aimed to assess the prognostic role of endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG), as early predictors of mortality, invasive mechanical ventilation (IMV) requirement, and length of stay (LOS) in patients with sepsis. Materials and Methods: In total, 106 patients with confirmed sepsis were enrolled in this study. The patients were divided into groups according to mortality outcome (survival, N=53; nonsurvival, N=53), IMV requirement (IMV group, N=26; non-IMV group, N=80), and LOS (LOS <10 days, N=59; LOS ≥10 days, N=47). Patients' clinical status was assessed along with laboratory biomarkers as well as AEA and 2-AG concentration measurements early on admission to emergency units. AEA and 2-AG levels were measured by enzyme-linked immunosorbent assay (ELISA) using an ELISA processor, EtiMax 3000 (DiaSorin, Saluggia, Italy). The predictive value of AEA and 2-AG for the studied sepsis outcomes and complications was analyzed using univariate and multivariate analyses and receiver operating characteristic (ROC) curve analysis. Results: Two endocannabinoids showed no significant difference between survivors and nonsurvivors, although an AEA concentration <7.16 μg/L predicted mortality outcome with a sensitivity of 57% (95% confidence interval [CI] 42-71) and specificity of 80% (95% CI 66-91). AEA concentrations ≤17.84 μg/L predicted LOS ≥10 days with sensitivity of 98% (95% CI 89-100) and specificity of 34% (95% CI 22-47). When analyzing IMV requirement, levels of AEA and 2-AG were significantly lower within the IMV group compared with the non-IMV group (5.94 μg/L [2.04-9.44] and 6.70 μg/L [3.50-27.04], p=0.043, and 5.68 μg/L [2.30-8.60] and 9.58 μg/L [4.83-40.05], p=0.002, respectively). The 2-AG showed the best performance for IMV requirement prediction, with both sensitivity and specificity of 69% (p<0.001). Endocannabinoid AEA was an independent risk factor of LOS ≥10 days (odds ratio [OR] 23.59; 95% CI 3.03-183.83; p=0.003) and IMV requirement in sepsis (OR 0.79; 95% CI, 0.67-0.93; p=0.004). Conclusion: Low AEA concentration is a prognostic factor of hospital LOS longer than 10 days. Lower AEA and 2-AG concentrations obtained at the time of admission to the hospital are predictors of IMV requirement.

Targeting temperature-sensitive transient receptor potential channels in hypertension: far beyond the perception of hot and cold

Transient receptor potential (TRP) channels are nonselective cation channels and participate in various physiological roles. Thus, changes in TRP channel function or expression have been linked to several disorders. Among the many TRP channel subtypes, the TRP ankyrin type 1 (TRPA1), TRP melastatin type 8 (TRPM8), and TRP vanilloid type 1 (TRPV1) channels are temperature-sensitive and recognized as thermo-TRPs, which are expressed in the primary afferent nerve. Thermal stimuli are converted into neuronal activity. Several studies have described the expression of TRPA1, TRPM8, and TRPV1 in the cardiovascular system, where these channels can modulate physiological and pathological conditions, including hypertension. This review provides a complete understanding of the functional role of the opposing thermo-receptors TRPA1/TRPM8/TRPV1 in hypertension and a more comprehensive appreciation of TRPA1/TRPM8/TRPV1-dependent mechanisms involved in hypertension. These channels varied activation and inactivation have revealed a signaling pathway that may lead to innovative future treatment options for hypertension and correlated vascular diseases.

Lipids as Targets for Renal Cell Carcinoma Therapy

Kidney cancer is among the top ten most common cancers to date. Within the kidney, renal cell carcinoma (RCC) is the most common solid lesion occurring. While various risk factors are suspected, including unhealthy lifestyle, age, and ethnicity, genetic mutations seem to be a key risk factor. In particular, mutations in the von Hippel-Lindau gene (Vhl) have attracted a lot of interest since this gene regulates the hypoxia inducible transcription factors HIF-1α and HIF-2α, which in turn drive the transcription of many genes that are important for renal cancer growth and progression, including genes involved in lipid metabolism and signaling. Recent data suggest that HIF-1/2 are themselves regulated by bioactive lipids which make the connection between lipids and renal cancer obvious. This review will summarize the effects and contributions of the different classes of bioactive lipids, including sphingolipids, glycosphingolipids, eicosanoids, free fatty acids, cannabinoids, and cholesterol to renal carcinoma progression. Novel pharmacological strategies interfering with lipid signaling to treat renal cancer will be highlighted.

The Effect of Cannabis Plant Extracts on Head and Neck Squamous Cell Carcinoma and the Quest for Cannabis-Based Personalized Therapy

Cannabis sativa plants have a wide diversity in their metabolite composition among their different chemovars, facilitating diverse anti-tumoral effects on cancer cells. This research examined the anti-tumoral effects of 24 cannabis extracts representative of three primary types of chemovars on head and neck squamous cell carcinoma (HNSCC). The chemical composition of the extracts was determined using High-Performance Liquid Chromatography (HPLC) and Mass Spectrometry (MS). The most potent anti-tumoral extracts were type III decarboxylated extracts, with high levels of Cannabidiol (CBD). We identified extract 296 (CAN296) as the most potent in inducing HNSCC cell death via proapoptotic and anti-proliferative effects. Using chemical fractionation of CAN296, we identified the CBD fraction as the primary inducer of the anti-tumoral activity. We succeeded in defining the combination of CBD with cannabichromene (CBC) or tetrahydrocannabinol (THC) present in minute concentrations in the extract, yielding a synergic impact that mimics the extract's full effect. The cytotoxic effect could be maximized by combining CBD with either CBC or THC in a ratio of 2:1. This research suggests using decarboxylated CBD-type extracts enriched with CBC for future preclinical trials aimed at HNSCC treatment.

The Role of Neuro-Inflammation and Innate Immunity in Pathophysiology of Brain and Spinal Cord Tumors

Inflammation and innate immune system play a central role in cancers, including those affecting the central nervous system (CNS). Currently, classification of neoplasms, especially regarding gliomas, is established on molecular mutations in isocitrate dehydrogenase (IDH) genes and the presence of co-deletion 1p/19q. Treatment, in most of brain and spinal cord tumors, is centered on surgery, radiotherapy and pharmacological approaches with chemotherapeutic agents. However, the results of the treatments, after several decades, are not completely satisfactory. Cytokines and angiogenic factors are closely linked to the brain cancer behavior. Moreover, recent studies suggest a link between inflammation and tumorigenesis, underlying the complex nature of this topic, especially the anti- and pro-tumoral activities of inflammation and the two-way interactions between immune and tumor cells. The current understanding of the mechanisms by which CNS cancer cells modulate the immune system, especially how bi-directional communications between immune cells and tumor cells create an immunosuppressed microenvironment, gives important information about the promotion of tumor survival and growth. Here, we have briefly reviewed the current literature on this topic, focusing on the possible role of inflammation and innate immunity involved in the origin and in the development of CNS tumors.

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.

Therapeutic Effects of Cannabinoids and Their Applications in COVID-19 Treatment

Cannabis sativa is one of the first medicinal plants used by humans. Its medical use remains controversial because it is a psychotropic drug whose use has been banned. Recently, however, some countries have approved its use, including for recreational and medical purposes, and have allowed the scientific study of its compounds. Cannabis is characterized by the production of special types of natural products called phytocannabinoids that are synthesized exclusively by this genus. Phytocannabinoids and endocannabinoids are chemically different, but both pharmacologically modulate CB1, CB2, GRP55, GRP119 and TRPV1 receptor activities, involving activities such as memory, sleep, mood, appetite and motor regulation, pain sensation, neuroinflammation, neurogenesis and apoptosis. Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are phytocannabinoids with greater pharmacological potential, including anti-inflammatory, neuroprotective and anticonvulsant activities. Cannabidiol is showing promising results for the treatment of COVID-19, due to its capability of acting on the unleashed cytokine storm, on the proteins necessary for both virus entry and replication and on the neurological consequences of patients who have been infected by the virus. Here, we summarize the latest knowledge regarding the advantages of using cannabinoids in the treatment of COVID-19.

Dietary PUFAs and Exercise Dynamic Actions on Endocannabinoids in Brain: Consequences for Neural Plasticity and Neuroinflammation

The brain and peripheral nervous system provide oversight to muscle physiology and metabolism. Muscle is the largest organ in the body and critical for glucose sensitivity, prevention of diabetes, and control of obesity. The central nervous system produces endocannabinoids (eCBs) that play a role in brain neurobiology, such as inflammation and pain. Interestingly, studies in humans and rodents show that a moderate duration of exercise increases eCBs in the brain and blood and influences cannabinoid receptors. Cannabinoid actions in the nervous system have advanced our understanding of pain, well-being, and disease. Nutrition is an important aspect of brain and eCB physiology because eCBs are biosynthesized from PUFAs. The primary eCB metabolites are derived from arachidonic acid, a 20:4n-6 (ω-6) PUFA, and the n-3 (ω-3) PUFAs, EPA and DHA. The eCBs bind to cannabinoid receptors CB1 and CB2 to exert a wide range of activities, such as stimulating appetite, influencing energy metabolism, supporting the immune system, and facilitating neuroplasticity. A diet containing different essential n-6 and n-3 PUFAs will dominate the formation of specific eCBs, and subsequently their actions as ligands for CB1 and CB2. The eCBs also function as substrates for cyclooxygenase enzymes, including potential substrates for the oxylipins (OxLs), which can be proinflammatory. Together, the eCBs and OxLs act as modulators of neuroinflammation. Thus, dietary PUFAs have implications for exercise responses via synthesis of eCBs and their effects on neuroinflammation. Neurotrophins also participate in interactions between diet and the eCBs, specifically brain-derived neurotrophic factor (BDNF). BDNF supports neuroplasticity in cooperation with the endocannabinoid system (ECS). This review will describe the role of PUFAs in eCB biosynthesis, discuss the ECS and OxLs in neuroinflammation, highlight the evidence for exercise effects on eCBs, and describe eCB and BDNF actions on neuroplasticity.

Optimized flow cytometric detection of transient receptor potential vanilloid-1 (TRPV1) in human hematological malignancies

The ectopic overexpression of transient receptor potential vanilloid-1 (TRPV1) has been detected in numerous solid cancers, including breast, prostate, pancreatic, and tongue epithelium cancer. However, the expression of TRPV1 in hematological malignancies remains unknown. Here we show through in silico analysis that elevated TRPV1 mRNA expression occurs in a range of hematological malignancies and presents an optimized flow cytometry method to rapidly assess TRPV1 protein expression for both cell lines and primary patient samples. Three anti-TRPV1 antibodies were evaluated for intracellular TRPV1 detection using flow cytometry resulting in an optimized protocol for the evaluation of TRPV1 in hematological malignant cell lines and patients' peripheral blood mononuclear cells (PBMC). Overexpression of TRPV1 was observed in THP-1 (acute monocytic leukemia) and U266B1 (multiple myeloma, MM), but not U937 (histiocytic lymphoma) compared to healthy PBMC. TRPV1 was also detected in all 49 patients including B-cell non-Hodgkin's lymphoma (B-NHL), MM, and others and 20 healthy controls. TRPV1 expression was increased in 8% of patients (MM = 2, B-NHL = 2). In conclusion, we provide an optimized flow cytometry method for routine expression analysis of clinical samples and show that TRPV1 is increased in a subset of patients with hematological malignancies.

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.

Cannabidiol and Other Phytocannabinoids as Cancer Therapeutics

Preclinical models provided ample evidence that cannabinoids are cytotoxic against cancer cells. Among the best studied phytocannabinoids, cannabidiol (CBD) is most promising for the treatment of cancer as it lacks the psychotomimetic properties of delta-9-tetrahydrocannabinol (THC). In vitro studies and animal experiments point to a concentration- (dose-)dependent anticancer effect. The effectiveness of pure compounds versus extracts is the subject of an ongoing debate. Actual results demonstrate that CBD-rich hemp extracts must be distinguished from THC-rich cannabis preparations. Whereas pure CBD was superior to CBD-rich extracts in most in vitro experiments, the opposite was observed for pure THC and THC-rich extracts, although exceptions were noted. The cytotoxic effects of CBD, THC and extracts seem to depend not only on the nature of cannabinoids and the presence of other phytochemicals but also largely on the nature of cell lines and test conditions. Neither CBD nor THC are universally efficacious in reducing cancer cell viability. The combination of pure cannabinoids may have advantages over single agents, although the optimal ratio seems to depend on the nature of cancer cells; the existence of a 'one size fits all' ratio is very unlikely. As cannabinoids interfere with the endocannabinoid system (ECS), a better understanding of the circadian rhythmicity of the ECS, particularly endocannabinoids and receptors, as well as of the rhythmicity of biological processes related to the growth of cancer cells, could enhance the efficacy of a therapy with cannabinoids by optimization of the timing of the administration, as has already been reported for some of the canonical chemotherapeutics. Theoretically, a CBD dose administered at noon could increase the peak of anandamide and therefore the effects triggered by this agent. Despite the abundance of preclinical articles published over the last 2 decades, well-designed controlled clinical trials on CBD in cancer are still missing. The number of observations in cancer patients, paired with the anticancer activity repeatedly reported in preclinical in vitro and in vivo studies warrants serious scientific exploration moving forward.

Deletion of fatty acid amide hydrolase reduces lyso-sulfatide levels but exacerbates metachromatic leukodystrophy in mice

An inherited deficiency of arylsulfatase A (ASA) causes the lysosomal storage disease metachromatic leukodystrophy (MLD) characterized by massive intralysosomal storage of the acidic glycosphingolipid sulfatide and progressive demyelination. Lyso-sulfatide, which differs from sulfatide by the lack of the N-linked fatty acid also accumulates in MLD and is considered a key driver of pathology although its concentrations are far below sulfatide levels. However, the metabolic origin of lyso-sulfatide is unknown. We show here that ASA-deficient murine macrophages and microglial cells express an endo-N-deacylase that cleaves the N-linked fatty acid from sulfatide. An ASA-deficient astrocytoma cell line devoid of this activity was used to identify the enzyme by overexpressing 13 deacylases with potentially matching substrate specificities. Hydrolysis of sulfatide was detected only in cells overexpressing the enzyme fatty acid amide hydrolase (FAAH). A cell-free assay with recombinant FAAH confirmed the novel role of this enzyme in sulfatide hydrolysis. Consistent with the in vitro data, deletion of FAAH lowered lyso-sulfatide levels in a mouse model of MLD. Regardless of the established cytotoxicity of lyso-sulfatide and the anti-inflammatory effects of FAAH inhibition seen in mouse models of several neurological diseases, genetic inactivation of FAAH did not mitigate, but rather exacerbated the disease phenotype of MLD mice. This unexpected finding was reflected by worsening of rotarod performance, increase of anxiety-related exploratory activity, aggravation of peripheral neuropathy and reduced life expectancy. Thus, we conclude that FAAH has a protective function in MLD and may represent a novel therapeutic target for treatment of this fatal condition.

The major endocannabinoid anandamide (AEA) induces apoptosis of human granulosa cells

The endocannabinoid system (ECS) plays a crucial role in human reproduction. Changes in anandamide (AEA) levels affect reproductive events and has already been suggested as biomarker of reproductive potential of male and female gametes. Although cannabinoid-receptor 1 (CB1) was already identified in human granulosa cells (hGCs) the ECS was not characterized on granulosa cells line COV434 nor the effects of AEA on GCs viability and function depicted. Therefore, the aim of this study was to characterize the ECS elements and explore the effects of AEA on both COV434 and hGCs. Our results revealed that hGCs express the full enzymatic machinery responsible for AEA metabolism as well as cannabinoid receptors. In addition, AEA induced a reduction in both COV434 and hGCs viability in a concentration and time-dependent manner. Nevertheless, the effects of AEA in cell viability was independent of either CB1 or CB2 receptors. There was no ROS release in both cell models; however, AEA induced morphological changes, presenting chromatin condensation at 72 h, and variation on mitochondrial membrane potential. Moreover, AEA induced an increase in caspase -3/-7 activities in both cell models, but in hGCs there was also an increase in caspase 8 activity. This study supports the idea that ECS balance is crucial for folliculogenesis and oocyte quality as dysregulated AEA levels may compromise female fertility.

Endocannabinoids Regulate Stem Cells of the Apical Papilla via a Cannabinoid Receptor and TRPV1-Independent Mechanism

INTRODUCTION

Endogenous cannabinoids (endocannabinoids [eCBs]) have been shown to have a multitude of functions including neurotransmission and immune modulatory effects. This study aimed to evaluate if stem cells of the apical papilla (SCAP) express the receptors and enzymes of the endocannabinoid system (ECS) and whether eCBs regulate their proliferation and mineralization potential.

METHODS

Gene expression of the main components of the ECS and transient receptor potential vanilloid 1 (TRPV1) was evaluated in SCAP cultures. SCAP were treated with 2 concentrations of eCBs and/or capsazepine, a TRPV1 antagonist. SCAP viability was evaluated after 1, 4, and 7 days. Osteogenic differentiation was assessed after 14 days, and the gene expression of mineralization markers was assessed after 7 days.

RESULTS

The enzymes of ECS and TRPV1 but not the cannabinoid receptors (cannabinoid receptors 1 and 2) were expressed in SCAP. Anandamide, 2-arachidonoylglycerol, and N-arachidonoylphenolamine (AM-404) reduced SCAP viability in all experimental periods at the highest concentration compared with the group with no treatment. Anandamide and AM-404 did not inhibit SCAP differentiation potential, but 2-arachidonoylglycerol at the highest concentration did. SCAP treated with AM-404 presented a down-regulation in gene expression of alkaline phosphatase (ALP), dentin matrix protein 1 (DMP-1), and dentin sialophosphoprotein (DSPP) compared with the proliferation medium group but not with control group.

CONCLUSIONS

SCAP expressed the genes of the main components of ECS and TRPV1, and eCBs can affect SCAP viability, mineralization, and gene expression.

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 Endocannabinoid System in the Mediterranean Mussel Mytilus galloprovincialis: Possible Mediators of the Immune Activity?

Anandamide (AEA) is one of the best characterized members of the endocannabinoid family and its involvement in many pathophysiological processes has been well documented in vertebrates and invertebrates. Here, we report the biochemical and functional characterization of key elements of the endocannabinoid system in hemocytes isolated from the Mediterranean mussel Mytilus galloprovincialis. We also show the effects of exogenous AEA, as well as of capsaicin, on the cell ability to migrate and to activate the respiratory burst, upon in vitro stimulation of phagocytosis. Interestingly, our findings show that both AEA and capsaicin suppress the hemocyte response and that the use of selective antagonists of CB₂ and TRPV1 receptors revert their inhibitory effects. Overall, present data support previous evidence on the presence of endocannabinoid signaling in mollusks and advance our knowledge about the evolutionary origins of this endogenous system and its role in the innate response of mollusks.

Molecular Mechanism of Autophagy and Its Regulation by Cannabinoids in Cancer

Simple Summary

This review examines the complex function of autophagy in malignancy and explores its regulation by cannabinoids in different cancers. Autophagy is an important process in the maintenance of cellular homeostasis, through the degradation and recycling of cytoplasmic constituents. The action of autophagy is highly dependent on tumour stage and type and the receptors with which ligands interact. Cannabinoids are growingly being acknowledged for their anticancer activities and are known to stimulate several mechanisms such as apoptosis and autophagy. Better understanding the mechanism of action behind autophagy and its regulation by cannabinoids will allow the development of novel cancer therapeutics.

Abstract

Autophagy is a “self-degradation” process whereby malfunctioned cytoplasmic constituents and protein aggregates are engulfed by a vesicle called the autophagosome, and subsequently degraded by the lysosome. Autophagy plays a crucial role in sustaining protein homeostasis and can be an alternative source of energy under detrimental circumstances. Studies have demonstrated a paradoxical function for autophagy in cancer, displaying both tumour suppressive and tumour promotive roles. In early phases of tumour development autophagy promotes cancer cell death. In later phases, autophagy enables cancer cells to survive and withstand therapy. Cannabinoids, which are derivatives of the Cannabis sativa L. plant, have shown to be associated with autophagy induction in cells. There is an emerging interest in studying the signalling pathways involved in cannabinoid-induced autophagy and their potential application in anticancer therapies. In this review, the molecular mechanisms involved in the autophagy degradation process will be discussed. This review also highlights a role for autophagy in cancer progression, with cannabinoid-induced autophagy presenting a novel strategy for anticancer therapy.

CBD activation of TRPV1 induces oxidative signaling and subsequent ER stress in breast cancer cell lines

Endoplasmic reticulum (ER) stress is an imbalance between the protein-folding load and capacity of ER. It can be induced by various physiological conditions, activating the unfolded protein response (UPR) to re-establish homeostasis, promoting cell survival. Under severe or chronic stress, apoptosis is induced. Normal cells generally do not experience continuous ER stress induction. The stressful conditions experienced in the tumor microenvironment facilitate chronic ER stress and UPR activation, which plays a pivotal role in tumour survival. Exacerbation of pre-existing ER stress can trigger cancer cell death, with a minimal effect on normal cells. Current literature suggests that cannabinoid treatment may induce cancer cell death via ER stress; however, little is known about the mechanisms of induction. This study proposed that cannabidiol (CBD) mechanism occurred through the influx of Ca²⁺ via the TRPV1 receptor, and increasing reactive oxygen species (ROS) production affects protein folding and induces ER stress. ER stress was induced, and detection and quantification were completed using Thioflavin T staining and GRP78 by western blot analysis. The effect of cannabinoid treatment on ROS production and Ca²⁺ influx was measured. CBD was the most potent ER stress inducer, significantly increasing Ca²⁺ and ROS accumulation. Concomitant treatment with CBD and an antioxidant significantly increased cell viability and decreased ER stress induction in the MCF7 cell line. Concomitant treatment with a TRPV1 antagonist increased viability in this cell line. In conclusion, the data suggested that CBD induced ER stress via Ca²⁺ influx through the TRPV1 receptor, thereby elevating intracellular ROS levels and disrupting protein folding.

Endocannabinoids and aging-Inflammation, neuroplasticity, mood and pain

Aging is associated with changes in hormones, slowing of metabolism, diminished physiological processes, chronic inflammation and high exposure to oxidative stress factors, generally described as the biological cost of living. Lifestyle interventions of diet and exercise can improve the quality of life during aging and lower diet-related chronic disease. The endocannabinoid system (ECS) has important effects on systemic metabolism and physiological systems, including the central and peripheral nervous systems. Exercise can reduce the loss of muscle mass and improve strength, and increase the levels of endocannabinoids (eCB) in brain and blood. Although the ECS exerts controls on multiple systems throughout life it affords benefits to natural aging. The eCB are synthesized from polyunsaturated fatty acids (PUFA) and the primary ones are produced from arachidonic acid (n-6 PUFA) and others from the n-3 PUFA, namely eicosapentaenoic and docosahexaenoic acids. The eCB ligands bind to their receptors, CB1 and CB2, with effects on appetite stimulation, metabolism, immune functions, and brain physiology and neuroplasticity. Dietary families of PUFA are a primary factor that can influence the types and levels of eCB and as a consequence, the downstream actions when the ligands bind to their receptors. Furthermore, the association of eCB with the synthesis of oxylipins (OxL) is a connection between the physiological actions of eCB and the lipid derived immunological OxL mediators of inflammation. OxL are ubiquitous and influence neuroinflammation and inflammatory processes. The emerging actions of eCB on neuroplasticity, well-being and pain are important to aging. Herein, we present information about the ECS and its components, how exercise and diet affects specific eCB, their role in neuroplasticity, neuroinflammation, pain, mood, and relationship to OxL. Poor nutrition status and low nutrient intakes observed with many elderly are reasons to examine the role of dietary PUFA actions on the ECS to improve health.

Therapeutic potential of cannabinoids in combination cancer therapy

Derivatives of the plant Cannabis sativa have been used for centuries for both medical and recreational purposes, as well as industrial. The first proof of its medicinal use comes from ancient China, although there is evidence of its earlier utilization in Europe and Asia. In the 19th century, European practitioners started to employ cannabis extracts to treat tetanus, convulsions, and mental diseases and, in 1851, cannabis made its appearance in the Pharmacopoeia of the United States as an analgesic, hypnotic and anticonvulsant. It was only in 1937 that the Marijuana Tax Act prohibited the use of this drug in the USA. The general term Cannabis is commonly used by the scientific and scholar community to indicate derivatives of the plant Cannabis sativa. The word cannabinoid is a term describing chemical compounds that are either derivate of Cannabis (phytocannabinoids) or artificial analogues (synthetic) or are produced endogenously by the body (endocannabinoids). A more casual term "marijuana" or "weed", a compound derived from dried Cannabis flower tops and leaves, has progressively superseded the term cannabis when referred to its recreational use. The 2018 World health organisation (WHO) data suggest that nearly 2.5% of the global population (147 million) uses marijuana and some countries, such as Canada and Uruguay, have already legalised it. Due to its controversial history, the medicinal use of cannabinoids has always been a centre of debate. The isolation and characterisation of Δ⁹ tetrahydrocannabinol (THC), the major psychoactive component of cannabis and the detection of two human cannabinoid receptor (CBRs) molecules renewed interest in the medical use of cannabinoids, boosting research and commercial heed in this sector. Some cannabinoid-based drugs have been approved as medications, mainly as antiemetic, antianorexic, anti-seizure remedies and in cancer and multiple sclerosis patients' palliative care. Nevertheless, due to the stigma commonly associated with these compounds, cannabinoids' potential in the treatment of conditions such as cancer is still largely unknown and therefore underestimated.

Cannabis and its constituents for cancer: History, biogenesis, chemistry and pharmacological activities

Cannabis has long been used for healing and recreation in several regions of the world. Over 400 bioactive constituents, including more than 100 phytocannabinoids, have been isolated from this plant. The non-psychoactive cannabidiol (CBD) and the psychoactive Δ⁹-tetrahydrocannabinol (Δ⁹-THC) are the major and widely studied constituents from this plant. Cannabinoids exert their effects through the endocannabinoid system (ECS) that comprises cannabinoid receptors (CB1, CB2), endogenous ligands, and metabolizing enzymes. Several preclinical studies have demonstrated the potential of cannabinoids against leukemia, lymphoma, glioblastoma, and cancers of the breast, colorectum, pancreas, cervix and prostate. Cannabis and its constituents can modulate multiple cancer related pathways such as PKB, AMPK, CAMKK-β, mTOR, PDHK, HIF-1α, and PPAR-γ. Cannabinoids can block cell growth, progression of cell cycle and induce apoptosis selectively in tumour cells. Cannabinoids can also enhance the efficacy of cancer therapeutics. These compounds have been used for the management of anorexia, queasiness, and pain in cancer patients. Cannabinoid based products such as dronabinol, nabilone, nabiximols, and epidyolex are now approved for medical use in cancer patients. Cannabinoids are reported to produce a favourable safety profile. However, psychoactive properties and poor bioavailability limit the use of some cannabinoids. The Academic Institutions across the globe are offering training courses on cannabis. How cannabis and its constituents exert anticancer activities is discussed in this article. We also discuss areas that require attention and more extensive research.

Oleamide Induces Cell Death in Glioblastoma RG2 Cells by a Cannabinoid Receptor-Independent Mechanism

The endocannabinoid system has been associated with antiproliferative effects in several types of tumors through cannabinoid receptor-mediated cell death mechanisms. Oleamide (ODA) is a CB1/CB2 agonist associated with cell growth and migration by adhesion and/or ionic signals associated with Gap junctions. Antiproliferative mechanisms related to ODA remain unknown. In this work, we evaluated the effects of ODA on cell viability and morphological changes in a rat RG2 glioblastoma cell line and compared these effects with primary astrocyte cultures from 8-day postnatal rats. RG2 and primary astrocyte cultures were treated with ODA at increasing concentrations (25, 50, 100, and 200 μM) for different periods of time (12, 24, and 48 h). Changes in RG2 cell viability and morphology induced by ODA were assessed by viability/mitochondrial activity test and phase contrast microscopy, respectively. The ratios of necrotic and apoptotic cell death, and cell cycle alterations, were evaluated by flow cytometry. The roles of CB1 and CB2 receptors on ODA-induced changes were explored with specific receptor antagonists. ODA (100 μM) induced somatic damage, detachment of somatic bodies, cytoplasmic polarization, and somatic shrinkage in RG2 cells at 24 and 48 h. In contrast, primary astrocytes treated at the same ODA concentrations exhibited cell aggregation but not cell damage. ODA (100 μM) increased apoptotic cell death and cell arrest in the G1 phase at 24 h in the RG2 line. The effects induced by ODA on cell viability of RG2 cells were independent of CB1 and CB2 receptors or changes in intracellular calcium transient. Results of this novel study suggest that ODA exerts specific antiproliferative effects on RG2 glioblastoma cells through unconventional apoptotic mechanisms not involving canonical signals.

The endocannabinoid signaling pathway as an emerging target in pharmacotherapy, earmarking mitigation of destructive events in rheumatoid arthritis

Rheumatoid arthritis is an inflammatory autoimmune disease, characterized by synovial proliferation, destruction to articular cartilage and severe pain. The cannabinoids obtained from Cannabis sativa exhibited their actions via cannabinoid-1 and -2 receptors, which also provides a platform for endocannabinoids to act. The endocannabinoid system comprises endocannabinoid molecules involved in signaling processes, along with G-protein coupled receptors and enzymes associated with ligand biosynthesis, activation and degradation. The action of endocannabinoid system in immune system regulation, via primary CB2 activation, followed by inhibition of production of pro-inflammatory cytokines, auto-antibodies and MMPs, FLSs proliferation and T-cell mediated immune response, are elaborated as potential therapeutic regimes in rheumatoid arthritis. The involvement of endocannabinoid system in immune cells like, B cells, T cells and macrophages, as well as regulatory actions on sensory noniceptors to ameliorate pain is significantly highlighted in the review, elaborating the actions of endocannabinoid signaling in mitigating the disease events. The review also focuses on enhancement of endocannabinoid tone, either by inhibiting the degradation enzymes, like FAAH, MAGL, COX, CytP450, LOX, etc. or by retarding cellular uptake processes. Moreover, the review portrays the optimizing role of endocannabinoid system, in abbreviating the symptoms and complications of rheumatoid arthritis in patients and mitigating inflammation, pain and immune mediated effects significantly.

Anticancer effects of n-3 EPA and DHA and their endocannabinoid derivatives on breast cancer cell growth and invasion

The anticancer effects of the omega-3 long chain polyunsaturated fatty acids (LCPUFA), EPA and DHA may be due, at least in part, to conversion to their respective endocannabinoid derivatives, eicosapentaenoyl-ethanolamine (EPEA) and docosahexaenoyl-ethanolamine (DHEA). Here, the effects of EPEA and DHEA and their parent compounds, EPA and DHA, on breast cancer (BC) cell function was examined. EPEA and DHEA exhibited greater anti-cancer effects than EPA and DHA in two BC cells (MCF-7 and MDA-MB-231) whilst displaying no effect in non-malignant breast cells (MCF-10a). Both BC lines expressed CB_1/2 receptors that were responsible, at least partly, for the observed anti-proliferative effects of the omega-3 endocannabinoids as determined by receptor antagonism studies. Additionally, major signalling mechanisms elicited by these CB ligands included altered phosphorylation of p38-MAPK, JNK, and ERK proteins. Both LCPUFAs and their endocannabinoids attenuated the expression of signal proteins in BC cells, albeit to different extents depending on cell type and lipid effectors. These signal proteins are implicated in apoptosis and attenuation of BC cell migration and invasiveness. Furthermore, only DHA reduced in vitro MDA-MB-231 migration whereas both LCPUFAs and their endocannabinoids significantly inhibited invasiveness. This finding was consistent with reduced integrin β3 expression observed with all treatments and reduced MMP-1 and VEGF with DHA treatment. Attenuation of cell viability, migration and invasion of malignant cells indicates a potential adjunct nutritional therapeutic use of these LCPUFAs and/or their endocannabinoids in treatment of breast cancer.

Can Hemp Help? Low-THC Cannabis and Non-THC Cannabinoids for the Treatment of Cancer

Cannabis has been used to relieve the symptoms of disease for thousands of years. However, social and political biases have limited effective interrogation of the potential benefits of cannabis and polarised public opinion. Further, the medicinal and clinical utility of cannabis is limited by the psychotropic side effects of ∆⁹-tetrahydrocannabinol (∆⁹-THC). Evidence is emerging for the therapeutic benefits of cannabis in the treatment of neurological and neurodegenerative diseases, with potential efficacy as an analgesic and antiemetic for the management of cancer-related pain and treatment-related nausea and vomiting, respectively. An increasing number of preclinical studies have established that ∆⁹-THC can inhibit the growth and proliferation of cancerous cells through the modulation of cannabinoid receptors (CB1R and CB2R), but clinical confirmation remains lacking. In parallel, the anti-cancer properties of non-THC cannabinoids, such as cannabidiol (CBD), are linked to the modulation of non-CB1R/CB2R G-protein-coupled receptors, neurotransmitter receptors, and ligand-regulated transcription factors, which together modulate oncogenic signalling and redox homeostasis. Additional evidence has also demonstrated the anti-inflammatory properties of cannabinoids, and this may prove relevant in the context of peritumoural oedema and the tumour immune microenvironment. This review aims to document the emerging mechanisms of anti-cancer actions of non-THC cannabinoids.

Cannabinoid Signaling in Glioma Cells

Cannabinoids are a group of structurally heterogeneous but pharmacologically related compounds, including plant-derived cannabinoids, synthetic substances and endogenous cannabinoids, such as anandamide and 2-arachidonoylglycerol. Cannabinoids elicit a wide range of central and peripheral effects mostly mediated through cannabinoid receptors. There are two types of specific G_i/o-protein-coupled receptors cloned so far, called CB1 and CB2, although an existence of additional cannabinoid-binding receptors has been suggested. CB1 and CB2 differ in their predicted amino acid sequence, tissue distribution, physiological role and signaling mechanisms. Significant alterations of a balance in the cannabinoid system between the levels of endogenous ligands and their receptors occur during malignant transformation in various types of cancer, including gliomas. Cannabinoids exert anti-proliferative action in tumor cells. Induction of cell death by cannabinoid treatment relies on the generation of a pro-apoptotic sphingolipid ceramide and disruption of signaling pathways crucial for regulation of cellular proliferation, differentiation or apoptosis. Increased ceramide levels lead also to ER-stress and autophagy in drug-treated glioblastoma cells. Beyond blocking of tumor cells proliferation cannabinoids inhibit invasiveness, angiogenesis and the stem cell-like properties of glioma cells, showing profound activity in the complex tumor microenvironment. Advances in translational research on cannabinoid signaling led to clinical investigations on the use of cannabinoids in treatments of glioblastomas.

Cannabinoid Receptor 2 (CB2) Signals via G-alpha-s and Induces IL-6 and IL-10 Cytokine Secretion in Human Primary Leukocytes

Cannabinoid receptor 2 (CB₂) is a promising therapeutic target for immunological modulation. There is, however, a deficit of knowledge regarding CB₂ signaling and function in human primary immunocompetent cells. We applied an experimental paradigm which closely models the in situ state of human primary leukocytes (PBMC; peripheral blood mononuclear cells) to characterize activation of a number of signaling pathways in response to a CB₂-selective ligand (HU308). We observed a "lag" phase of unchanged cAMP concentration prior to development of classically expected Gα_i-mediated inhibition of cAMP synthesis. Application of G protein inhibitors revealed that this apparent lag was a result of counteraction of Gα_i effects by concurrent Gα_s activation. Monitoring downstream signaling events showed that activation of p38 was mediated by Gα_i, whereas ERK1/2 and Akt phosphorylation were mediated by Gα_i-coupled βγ. Activation of CREB integrated multiple components; Gα_s and βγ mediated ∼85% of the response, while ∼15% was attributed to Gα_i. Responses to HU308 had an important functional outcome-secretion of interleukins 6 (IL-6) and 10 (IL-10). IL-2, IL-4, IL-12, IL-13, IL-17A, MIP-1α, and TNF-α were unaffected. IL-6/IL-10 induction had a similar G protein coupling profile to CREB activation. All response potencies were consistent with that expected for HU308 acting via CB₂. Additionally, signaling and functional effects were completely blocked by a CB₂-selective inverse agonist, giving additional evidence for CB₂ involvement. This work expands the current paradigm regarding cannabinoid immunomodulation and reinforces the potential utility of CB₂ ligands as immunomodulatory therapeutics.

The heterogeneity and complexity of Cannabis extracts as antitumor agents

The Cannabis plant contains over 100 phytocannabinoids and hundreds of other components. The biological effects and interplay of these Cannabis compounds are not fully understood and yet influence the plant's therapeutic effects. Here we assessed the antitumor effects of whole Cannabis extracts, which contained significant amounts of differing phytocannabinoids, on different cancer lines from various tumor origins. We first utilized our novel electrospray ionization liquid chromatography mass spectrometry method to analyze the phytocannabinoid contents of 124 Cannabis extracts. We then monitored the effects of 12 chosen different Cannabis extracts on 12 cancer cell lines. Our results show that specific Cannabis extracts impaired the survival and proliferation of cancer cell lines as well as induced apoptosis. Our findings showed that pure (-)-Δ⁹-trans-tetrahydrocannabinol (Δ⁹-THC) did not produce the same effects on these cell lines as the whole Cannabis extracts. Furthermore, Cannabis extracts with similar amounts of Δ⁹-THC produced significantly different effects on the survival of specific cancer cells. In addition, we demonstrated that specific Cannabis extracts may selectively and differentially affect cancer cells and differing cancer cell lines from the same organ origin. We also found that cannabimimetic receptors were differentially expressed among various cancer cell lines and suggest that this receptor diversity may contribute to the heterogeneous effects produced by the differing Cannabis extracts on each cell line. Our overall findings indicate that the effect of a Cannabis extract on a specific cancer cell line relies on the extract's composition as well as on certain characteristics of the targeted cells.

Cannabinoids in Gynecological Diseases

The endocannabinoid system (ECS) is a multifunctional homeostatic system involved in many physiological and pathological conditions. The ligands of the ECS are the endo-cannabinoids, whose actions are mimicked by exogenous cannabinoids, such as phytocannabinoids and synthetic cannabinoids. Responses to the ligands of the ECS are mediated by numerous receptors like the classical cannabinoid receptors (CB₁ and CB₂) as well as ECS-related receptors, e.g., G protein-coupled receptors 18 and 55 (GPR18 and GPR55), transient receptor potential ion channels, and nuclear peroxisome proliferator-activated receptors. The ECS regulates almost all levels of female reproduction, starting with oocyte production through to parturition. Dysregulation of the ECS is associated with the development of gynecological disorders from fertility disorders to cancer. Cannabinoids that act at the ECS as specific agonists or antagonists may potentially influence dysregulation and, therefore, represent new therapeutic options for the therapy of gynecological disorders.

Modulation of the Endocannabinoid System as a Potential Anticancer Strategy

Currently, the involvement of the endocannabinoid system in cancer development and possible options for a cancer-regressive effect of cannabinoids are controversially discussed. In recent decades, a number of preclinical studies have shown that cannabinoids have an anticarcinogenic potential. Therefore, especially against the background of several legal simplifications with regard to the clinical application of cannabinoid-based drugs, an extended basic knowledge about the complex network of the individual components of the endocannabinoid system is required. The canonical endocannabinoid system consists of the endocannabinoids N-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol as well as the G_i/o protein-coupled transmembrane cannabinoid receptors CB₁ and CB₂. As a result of extensive studies on the broader effect of these factors, other fatty acid derivatives, transmembrane and intracellular receptors, enzymes and lipid transporters have been identified that contribute to the effect of endocannabinoids when defined in the broad sense as “extended endocannabinoid system.” Among these additional components, the endocannabinoid-degrading enzymes fatty acid amide hydrolase and monoacylglycerol lipase, lipid transport proteins of the fatty acid-binding protein family, additional cannabinoid-activated G protein-coupled receptors such as GPR55, members of the transient receptor family, and peroxisome proliferator-activated receptors were identified as targets for possible strategies to combat cancer progression. Other endocannabinoid-related fatty acids such as 2-arachidonoyl glyceryl ether, O-arachidonoylethanolamine, N-arachidonoyldopamine and oleic acid amide showed an effect via cannabinoid receptors, while other compounds such as endocannabinoid-like substances exert a permissive action on endocannabinoid effects and act via alternative intracellular target structures. This review gives an overview of the modulation of the extended endocannabinoid system using the example of anticancer cannabinoid effects, which have been described in detail in preclinical studies.

Low mRNA expression and activity of monoacylglycerol lipase in human SH-SY5Y neuroblastoma cells

Relatively little is known about the endocannabinoid system in human neuroblastoma cell lines. In the present study, we have investigated the expression of the genes coding for the enzymes involved in the synthesis and catabolism of endocannabinoids in the SH-SY5Y cell line. The expression of MGLL, the gene coding for the 2-arachidonoylglycerol hydrolytic enzyme monoacylglycerol lipase (MAGL), was found to be 85 and 340 fold lower than the expression levels for the genes coding for alpha/beta-hydrolase domain containing 6 and 12 (ABHD6, ABHD12), which are alternative hydrolytic enzymes for this endocannabinoid. In comparison, mRNA levels of MGLL were 1.5 fold higher than ABHD6 and 2 fold lower than the levels of ABHD12 in DU-145 human prostate cells. In functional assays, the hydrolysis of the 2-arachidonoylglycerol homologue 2-oleoylglycerol by intact SH-SY5Y cells was partially inhibited by the ABHD6 inhibitor WWL70, but not by the MAGL inhibitor JZL184, whereas the reverse was true in DU-145 cells. The combination of JZL184 + WWL70 did, however produce a significantly greater inhibition of 2-OG hydrolysis than seen with WWL70 alone in the SH-SY5Y cells. The low MGLL expression in the SH-SY5Y cells was not due to epigenetic silencing, since levels were not affected by treatment with the methylation inhibitor 5-aza-2'-deoxycytidine and/or the histone acetylase inhibitor trichostatin A. The low MGLL expression in SH-SY5Y cells should be taken into account when using these cells in experiments investigating the involvement of the endocannabinoid system in models of physiological and pathological processes.

Modulation of the Oxidative Stress and Lipid Peroxidation by Endocannabinoids and Their Lipid Analogues

Growing evidence supports the pivotal role played by oxidative stress in tissue injury development, thus resulting in several pathologies including cardiovascular, renal, neuropsychiatric, and neurodegenerative disorders, all characterized by an altered oxidative status. Reactive oxygen and nitrogen species and lipid peroxidation-derived reactive aldehydes including acrolein, malondialdehyde, and 4-hydroxy-2-nonenal, among others, are the main responsible for cellular and tissue damages occurring in redox-dependent processes. In this scenario, a link between the endocannabinoid system (ECS) and redox homeostasis impairment appears to be crucial. Anandamide and 2-arachidonoylglycerol, the best characterized endocannabinoids, are able to modulate the activity of several antioxidant enzymes through targeting the cannabinoid receptors type 1 and 2 as well as additional receptors such as the transient receptor potential vanilloid 1, the peroxisome proliferator-activated receptor alpha, and the orphan G protein-coupled receptors 18 and 55. Moreover, the endocannabinoids lipid analogues N-acylethanolamines showed to protect cell damage and death from reactive aldehydes-induced oxidative stress by restoring the intracellular oxidants-antioxidants balance. In this review, we will provide a better understanding of the main mechanisms triggered by the cross-talk between the oxidative stress and the ECS, focusing also on the enzymatic and non-enzymatic antioxidants as scavengers of reactive aldehydes and their toxic bioactive adducts.

Mechanistic study of nonivamide enhancement of hyperthermia-induced apoptosis in U937 cells

Hyperthermia is one therapeutic tool for damaging and killing cancer cells, with minimal injury to normal tissues. However, its cytotoxic effects alone are insufficient for quantitative cancer cell death. To overcome this limitation, several studies have explored non-toxic enhancers for hyperthermia-induced cell death. Capsaicin may be applicable as a therapeutic tool against various types of cancer. In the present study, we employed nonivamide, a less-pungent capsaicin analogue, to investigate its possible enhancing effects on hyperthermia-induced apoptosis; moreover, we analyzed its molecular mechanism. Treatment of U937 cells at 44 °C for 15 min, combined with nonivamide 50 μM, revealed enhancement of apoptosis. Significant increases in reactive oxygen species generation, mitochondrial dysfunction, and cleaved caspase-3 were observed during the combined treatment; these were accompanied by an increase in pro-apoptotic Bcl-2 family proteins and a decrease in anti-apoptotic Bcl-2 proteins. In addition, significant increases in p-JNK and p-p38 were detected, following the combined treatment. In conclusion, nonivamide enhanced hyperthermia-induced apoptosis via a mitochondrial-caspase dependent pathway. The underlying mechanism may include elevation of intracellular reactive oxygen species, mitochondrial dysfunction, and increased activation of JNK and p38.

Effects of CB2 and TRPV1 receptors' stimulation in pediatric acute T-lymphoblastic leukemia

T-Acute Lymphoblastic Leukemia (T-ALL) is less frequent than B-ALL, but it has poorer outcome. For this reason new therapeutic approaches are needed to treat this malignancy.

The Endocannabinoid/Endovanilloid (EC/EV) system has been proposed as possible target to treat several malignancies, including lymphoblastic diseases. The EC/EV system is composed of two G-Protein Coupled Receptors (CB1 and CB2), the Transient Potential Vanilloid 1 (TRPV1) channel, their endogenous and exogenous ligands and enzymes. CB1 is expressed mainly in central nervous system while CB2 predominantly on immune and peripheral cells, therefore we chose to selectively stimulate CB2 and TRPV1.

We treated T-ALL lymphoblasts derived from 4 patients and Jurkat cells with a selective agonist at CB2 receptor: JWH-133 [100 nM] and an agonist at TRPV1 calcium channel: RTX [5 uM] at 6, 12 and 24 hours. We analyzed the effect on apoptosis and Cell Cycle Progression by a cytofluorimetric assays and evaluated the expression level of several target genes (Caspase 3, Bax, Bcl-2, AKT, ERK, PTEN, Notch-1, CDK2, p53) involved in cell survival and apoptosis, by Real-Time PCR and Western Blotting.

We observed a pro-apoptotic, anti-proliferative effect of these compounds in both primary lymphoblasts obtained from patients with T-ALL and in Jurkat cell line. Our results show that both CB2 stimulation and TRPV1 activation, can increase the apoptosis in vitro, interfere with cell cycle progression and reduce cell proliferation, indicating that a new therapeutic approach to T-cell ALL might be possible by modulating CB2 and TRPV1 receptors.

Activation of the capsaicin-receptor TRPV1 by the acetaminophen metabolite N-arachidonoylaminophenol results in cytotoxicity

AIMS

The anandamide reuptake inhibitor N-arachidonoylaminophenol (AM404) and the reactive substance N-acetyl-p-benzoquinone imine (NAPQI) are both metabolites of acetaminophen and may contribute to acetaminophen-induced analgesia by acting at TRPV1 expressed in the peripheral or central nervous system. While NAPQI slowly sensitizes and activates TRPV1 by interacting with distinct intracellular cysteine residues, detailed properties of AM404 as an agonist of TRPV1 have not yet been reported on. We explored the effects of AM404 on recombinant human TRPV1 and in rodent dorsal root ganglion (DRG) neurons.

MATERIALS AND METHODS

HEK 293 cells expressing different isoforms of recombinant TRPV1 and rodent DRG neurons were employed for patch clamp and calcium imaging experiments. Cytotoxicity was assessed by propidium iodide and Annexin V staining on TRPV1-HEK 293 cells and with trypan blue staining on DRG neurons.

KEY FINDINGS

AM404 activates hTRPV1 at concentrations >1μM and in a concentration-dependent manner. AM404 also potentiates TRPV1-mediated currents evoked by heat and anandamide. Moreover, AM404-evoked currents are potentiated by NAPQI. While the partly capsaicin-insensitive rabbit (o) TRPV1 fails to respond to AM404, AM404-sensitivity is restored by insertion of the capsaicin binding-domain of rat TRPV1 into oTRPV1. In DRG neurons, AM404-evoked calcium influx as well as cell death is mediated by TRPV1.

SIGNIFICANCE

AM404 gates TRPV1 by interacting with the vanilloid-binding site, and TRPV1 is the main receptor for AM404 in DRG neurons. While direct activation of TRPV1 requires high concentrations of AM404, it is possible that synergistic effects of AM404 with further TRPV1-agonists may occur at clinically relevant concentrations.

N-Arachidonoyl Dopamine: A Novel Endocannabinoid and Endovanilloid with Widespread Physiological and Pharmacological Activities

N-arachidonoyl dopamine (NADA) is a member of the family of endocannabinoids to which several other N-acyldopamines belong as well. Their activity is mediated through various targets that include cannabinoid receptors or transient receptor potential vanilloid (TRPV)1. Synthesis and degradation of NADA are not yet fully understood. Nonetheless, there is evidence that NADA plays an important role in nociception and inflammation in the central and peripheral nervous system. The TRPV1 receptor, for which NADA is a potent agonist, was shown to be an endogenous transducer of noxious heat. Moreover, it has been demonstrated that NADA exerts protective and antioxidative properties in microglial cell cultures, cortical neurons, and organotypical hippocampal slice cultures. NADA is present in very low concentrations in the brain and is seemingly not involved in activation of the classical pathways. We believe that treatment with exogenous NADA during and after injury might be beneficial. This review summarizes the recent findings on biochemical properties of NADA and other N-acyldopamines and their role in physiological and pathological processes. These findings provide strong evidence that NADA is an effective agent to manage neuroinflammatory diseases or pain and can be useful in designing novel therapeutic strategies.

Cannabinoids as Modulators of Cell Death: Clinical Applications and Future Directions

Endocannabinoids are bioactive lipids that modulate various physiological processes through G-protein-coupled receptors (CB1 and CB2) and other putative targets. By sharing the activation of the same receptors, some phytocannabinoids and a multitude of synthetic cannabinoids mimic the effects of endocannabinoids. In recent years, a growing interest has been dedicated to the study of cannabinoids properties for their analgesic, antioxidant, anti-inflammatory and neuroprotective effects. In addition to these well-recognized effects, various studies suggest that cannabinoids may affect cell survival, cell proliferation or cell death. These observations indicate that cannabinoids may play an important role in the regulation of cellular homeostasis and, thus, may contribute to tissue remodelling and cancer treatment. For a long time, the study of cannabinoid receptor signalling has been focused on the classical adenylyl cyclase/cyclic AMP/protein kinase A (PKA) pathway. However, this pathway does not totally explain the wide array of biological responses to cannabinoids. In addition, the diversity of receptors and signalling pathways that endocannabinoids modulate offers an interesting opportunity for the development of specific molecules to disturb selectively the endogenous system. Moreover, emerging evidences suggest that cannabinoids ability to limit cell proliferation and to induce tumour-selective cell death may offer a novel strategy in cancer treatment. This review describes the main properties of cannabinoids in cell death and attempts to clarify the different pathways triggered by these compounds that may help to understand the complexity of respective molecular mechanisms and explore the potential clinical benefit of cannabinoids use in cancer therapies.

Endocannabinoid system and anticancer properties of cannabinoids

Cannabinoids impact human body by binding to cannabinoids receptors (CB1 and CB2). The two main phytocannabinoids are Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). THC interacts with CB1 receptors occurring in central nervous system and is responsible for psychoactive properties of marijuana. CBD has low affinity to CB1 receptor, has no psychoactive characteristics and its medical applications can be wider. CB receptors are part of a complex machinery involved in regulation of many physiological processes – endocannabinoid system. Cannabinoids have found some applications in palliative medicine, but there are many reports concerning their anticancer affects. Agonists of CB1 receptors stimulate accumulation of ceramides in cancer cells, stress of endoplasmic reticulum (ER stress) and, in turn, apoptosis. Effects of cannabinoids showing low affinity to CB receptors is mediated probably by induction of reactive oxygen species production.  Knowledge of antitumor activity of cannabinoids is still based only on preclinical studies and there is a necessity to conduct more experiments to assess the real potential of these compounds.

Relationship between in vitro sperm functional assessments, seminal plasma composition, and field fertility after AI with either non-sorted or sex-sorted bull semen

The hypothesis of this study was that different in vitro parameters are required to predict the in vivo fertility of non-sorted (NS) and sex-sorted (SS) semen. Thus, the aim was to correlate in vitro bull sperm functional parameters (experiment 1) and seminal plasma composition (experiment 2) with pregnancy rates using 2 cohorts of bulls (NS and SS). Experiment 1: ejaculates from each bull (n = 3 ejaculates per bull; n = 6 bulls for both NS and SS) were assessed for motility, thermal stress tolerance and morphology using microscopy, and viability, osmotic resistance, mitochondrial membrane potential, and acrosome integrity using flow cytometry. Fertilizing ability was assessed using IVF. Experiment 2: ejaculates (n = 3 per bull; n = 8 and 6 bulls for NS and SS, respectively) were collected, seminal plasma harvested and frozen and later analyzed for amino acid and fatty acid composition using gas chromatography mass spectrometry. In the NS cohort of bulls, there was no correlation between pregnancy rate and any of the sperm functional parameters assessed. However, within the SS cohort, motility and viability were correlated with pregnancy rate (r = 0.84 and 0.80, respectively; P < 0.05). There was no correlation between IVF outcome and pregnancy rate in either the SS or NS cohort of bulls. In the NS cohort of bulls, concentrations of the amino acid isoleucine and the fatty acid tricosylic acid (C23:0) were correlated with pregnancy rate (r = 0.80 and 0.74, respectively; P < 0.05). Within the SS cohort of bulls, the amino acid glutamic acid and the fatty acid arachidic acid (C20:0) were correlated with pregnancy rate (r = 0.84 and 0.82, respectively; P < 0.05). In conclusion, this study suggests that different in vitro markers of fertility are required to predict the fertility of NS and SS sperm.

URB597 inhibits oxidative stress induced by alcohol binging in the prefrontal cortex of adolescent rats

Heavy episodic drinking (binging), which is highly prevalent among teenagers, results in oxidative damage. Because the prefrontal cortex (PFC) is not completely mature in adolescents, this brain region may be more vulnerable to the effects of alcohol during adolescence. As endocannabinoids may protect the immature PFC from the harmful effects of high doses of alcohol, this study investigated the effect of the fatty acid amide hydrolase (FAAH) inhibitor URB597 on oxidative stress induced by acute or chronic binge alcohol intake in adolescent rats. At 40min after intraperitoneal pre-treatment with URB597 (0.3mg/kg) or vehicle (Veh), ethanol (EtOH; 3 or 6g/kg, intragastrically) or distilled water (DW) was administered in 3 consecutive sessions (acute binging) or 3 consecutive sessions over 4 weeks (chronic binging). Oxidative stress in PFC slices in situ was measured by dihydroethidium fluorescence staining. At the higher EtOH dose (6g/kg), pre-treatment with URB597 significantly reduced (p<0.01) the production of superoxide anions in the PFC after acute (42.8% decrease) and chronic binge EtOH consumption (44.9% decrease) compared with pre-treatment with Veh. As URB597 decreases anandamide metabolism, this evidence shows an antioxidant effect of endocannabinoids to suppress acute and chronic binge alcohol intake-induced oxidative stress in the PFC of adolescent rats.

Anti-carcinogenic activity of anandamide on human glioma in vitro and in vivo

The poor prognosis of gliomas is to a large extent attributed to the markedly proliferative and invasive nature of the disease. Endocannabinoids have emerged as novel potential anti-tumor agents. The present study aimed to investigate the anti-carcinogenic activity of anandamide (AEA), an endocannabinoid, on glioma cells. To assess the functional role of AEA in glioma, the effects of AEA on cell proliferation, migration, invasion, apoptosis and the cell cycle in vitro, and tumor growth in vivo, were investigated. AEA markedly inhibited the proliferation of U251 cells in a dose- and time-dependent manner. Flow cytometric assays revealed that the apoptosis rate of U251 cells upon treatment with AEA was increased. AEA also suppressed the adhesion, migration and invasion capabilities of the U251 cells. Furthermore, AEA inhibited tumor growth in vivo. These results highlighted the potential role of AEA in the tumorigenesis and progression of glioma, and suggested that AEA exhibits therapeutic potential in the management of human glioma.