Genetic and pharmacologic inactivation of cannabinoid CB1 receptor inhibits angiogenesis

The Impact of Potent Addictive Substances on Angiogenic Behavior: A Comprehensive Review

Angiogenesis, the formation of new vasculature from preexisting vasculature, is involved in the development of several diseases as well as various physiological processes. Strict cooperation of proangiogenic and antiangiogenic factors mediates the control of angiogenesis. The fundamental steps in angiogenesis include endothelial cell proliferation, migration, and invasion. Addictive substances, which are considered therapeutic candidates in research and medicine, are classified as natural substances, such as nicotine, or synthetic substances, such as synthetic cannabinoids. Addictive substances have been shown to either enhance or suppress angiogenesis. This review article provides an overview of recent studies concerning the effects of several addictive substances on the process of angiogenesis. Google Scholar and PubMed were used to collect the scientific literature used in this review. The addictive substances addressed in this review are nicotine, opioids such as morphine and heroin, alcohol, cocaine, methamphetamine, and cannabinoids. An accurate assessment of the influence of these substances on the angiogenic process may help to construct a potentially effective therapeutic protocol to control and treat several angiogenesis-related diseases.

Evaluation of the metabolic activity, angiogenic impacts, and GSK-3β signaling of the synthetic cannabinoid MMB-2201 on human cerebral microvascular endothelial cells

Angiogenesis is an intrinsic physiological process involving the formation of new capillaries from existing ones. Synthetic cannabinoids refer to a class of human-made chemicals that are primarily designed to mimic the effects of delta-9-tetrahydrocannabinol, the primary psychoactive compound in cannabis. Studies investigating the association between synthetic cannabinoids and cellular reactions are limited, and the available scientific evidence is insufficient. Consequently, the primary goal was to examine the effects of the synthetic cannabinoid MDMB-2201 on brain angiogenesis in vitro to provide a comprehensive analysis of MMB-2201's potential therapeutic or adverse effects on vascular development and related health conditions. Human Cerebral Microvascular Endothelial Cells (HBEC-5i) were incubated with MMB-2201, and their metabolic activity, migration rate, and tubular structure formation were examined. Expression levels of several angiogenesis-related proteins such as vascular endothelial growth factor (VEGF), Angiopoietin-1 (ANG-1), and Angiopoietin-2 (ANG-2) were assessed using western blot, ELISA, and real-time PCR. Furthermore, the phosphorylation of glycogen synthase kinase 3 beta (GSK-3β) at Ser9 induced by MMB-2201 was evaluated. HBEC-5i cells showed a significant increase in metabolic rate, enhanced migration, and sprouting of brain endothelial cells. Moreover, there was a noticeable increase in the mRNA and protein levels of VEGF, ANG-1, and ANG-2, as well as in the phosphorylation rate of GSK-3β at Ser9. This study paves the way for a novel pharmacological approach to addressing various angiogenesis-related diseases by targeting cannabinoid receptor type-1. Further exploration using different antagonists or agonists of cannabinoid receptors, depending on the specific characteristics of the disorders, may be necessary.

Adverse Ocular Impact and Emerging Therapeutic Potential of Cannabis and Cannabinoids: A Narrative Review

Cannabis is the most used drug worldwide with an estimated 219 million users. This narrative review aims to explore the adverse effects and therapeutic applications of cannabis and cannabinoids on the eye, given its growing clinical and non-clinical uses. The current literature reports several adverse ocular effects of cannabis and cannabinoids, including eyelid tremor, ptosis, reduced corneal endothelial cell density, dry eyes, red eyes, and neuro-retinal dysfunction. Cannabinoids may transiently impair night vision, depth perception, binocular and monocular contrast sensitivity, and dynamic visual acuity. Cannabinoids are not currently considered a first-line treatment option for any ocular conditions. Δ-9-tetrahydrocannabinol been shown to result in short-term intraocular pressure reduction, but insufficient evidence to support its use in treating glaucoma exists. Potential therapeutic applications of cannabinoids include their use as a second-line agent for treatment-refractory blepharospasm, for dry eye disease given corneal anti-inflammatory properties, and for suppression of pendular nystagmus in individuals with multiple sclerosis, which all necessitate further research for informed clinical practices.

Reduced fetal cerebral blood flow predicts perinatal mortality in a mouse model of prenatal alcohol and cannabinoid exposure

BACKGROUND

Children exposed prenatally to alcohol or cannabinoids individually can exhibit growth deficits and increased risk for adverse birth outcomes. However, these drugs are often co-consumed and their combined effects on early brain development are virtually unknown. The blood vessels of the fetal brain emerge and mature during the neurogenic period to support nutritional needs of the rapidly growing brain, and teratogenic exposure during this gestational window may therefore impair fetal cerebrovascular development.

STUDY DESIGN

To determine whether prenatal polysubstance exposure confers additional risk for impaired fetal-directed blood flow, we performed high resolution in vivo ultrasound imaging in C57Bl/6J pregnant mice. After pregnancy confirmation, dams were randomly assigned to one of four groups: drug-free control, alcohol-exposed, cannabinoid-exposed or alcohol-and-cannabinoid-exposed. Drug exposure occurred daily between Gestational Days 12-15, equivalent to the transition between the first and second trimesters in humans. Dams first received an intraperitoneal injection of either cannabinoid agonist CP-55,940 (750 µg/kg) or volume-equivalent vehicle. Then, dams were placed in vapor chambers for 30 min of inhalation of either ethanol or room air. Dams underwent ultrasound imaging on three days of pregnancy: Gestational Day 11 (pre-exposure), Gestational Day 13.5 (peri-exposure) and Gestational Day 16 (post-exposure).

RESULTS

All drug exposures decreased fetal cranial blood flow 24-hours after the final exposure episode, though combined alcohol and cannabinoid co-exposure reduced internal carotid artery blood flow relative to all other exposures. Umbilical artery metrics were not affected by drug exposure, indicating a specific vulnerability of fetal cranial circulation. Cannabinoid exposure significantly reduced cerebroplacental ratios, mirroring prior findings in cannabis-exposed human fetuses. Post-exposure cerebroplacental ratios significantly predicted subsequent perinatal mortality (p = 0.019, area under the curve, 0.772; sensitivity, 81%; specificity, 85.70%) and retroactively diagnosed prior drug exposure (p = 0.005; AUC, 0.861; sensitivity, 86.40%; specificity, 66.7%).

CONCLUSIONS

Fetal cerebrovasculature is significantly impaired by exposure to alcohol or cannabinoids, and co-exposure confers additional risk for adverse birth outcomes. Considering the rising potency and global availability of cannabis products, there is an imperative for research to explore translational models of prenatal drug exposure, including polysubstance models, to inform appropriate strategies for treatment and care in pregnancies affected by drug exposure.

Influencing Endothelial Cells' Roles in Inflammation and Wound Healing Through Nucleic Acid Delivery

Tissue engineering and wound-healing interventions are often designed for use in diseased and inflamed environments. In this space, endothelial cells (ECs) are crucial regulators of inflammation and healing, as they are the primary contact for recruitment of immune cells, as well as production of proinflammatory cytokines, which can stimulate or reduce inflammation. Alternatively, proliferation and spreading of ECs result in the formation of new vascular tissue or repair of damaged tissue, both critical for wound healing. Targeting ECs with specific nucleic acids could reduce unwanted inflammation or promote tissue regeneration as needed, which are two large issues involved in many regenerative medicine goals. Polymeric delivery systems are tools that can control the delivery of nucleic acids and prolong their effects. This review describes the use of polymeric vehicles for the delivery of nucleic acids to ECs for tissue engineering. Impact statement Tissue engineering is a rapidly growing field that has the potential to resolve many disease states and improve the quality of life of patients. In some applications, tissue-engineered strategies or constructs are developed to rebuild spaces damaged by disease or degeneration. To rebuild the native tissue, these constructs may need to interact with unwanted immune activity and cells. Various immune cells are often the focus of therapies as they are critical players in the inflammatory response; however, endothelial cells are also an extremely important and promising target in these cases. In addition, controlled delivery of specific-acting molecules, such as nucleic acids, is of growing interest for the regeneration and health of a variety of different tissues. It is important to understand what has been done and the potential of these targets and therapeutics for future investigation and advancements in tissue engineering.

Deciphering potential vascularization factors of on-chip co-cultured hiPSC-derived cerebral organoids

The lack of functional vascular system in stem cell-derived cerebral organoids (COs) limits their utility in modeling developmental processes and disease pathologies. Unlike other organs, brain vascularization is poorly understood, which makes it particularly difficult to mimic in vitro. Although several attempts have been made to vascularize COs, complete vascularization leading to functional capillary network development has only been achieved via transplantation into a mouse brain. Understanding the cues governing neurovascular communication is therefore imperative for establishing an efficient in vitro system for vascularized cerebral organoids that can emulate human brain development. Here, we used a multidisciplinary approach combining microfluidics, organoids, and transcriptomics to identify molecular changes in angiogenic programs that impede the successful in vitro vascularization of human induced pluripotent stem cell (iPSC)-derived COs. First, we established a microfluidic cerebral organoid (CO)-vascular bed (VB) co-culture system and conducted transcriptome analysis on the outermost cell layer of COs cultured on the preformed VB. Results revealed coordinated regulation of multiple pro-angiogenic factors and their downstream targets. The VEGF-HIF1A-AKT network was identified as a central pathway involved in the angiogenic response of cerebral organoids to the preformed VB. Among the 324 regulated genes associated with angiogenesis, six transcripts represented significantly regulated growth factors with the capacity to influence angiogenic activity during co-culture. Subsequent on-chip experiments demonstrated the angiogenic and vasculogenic potential of cysteine-rich angiogenic inducer 61 (CYR61) and hepatoma-derived growth factor (HDGF) as potential enhancers of organoid vascularization. Our study provides the first global analysis of cerebral organoid response to three-dimensional microvasculature for in vitro vascularization.

Novel micellar CB2 receptor agonist with anti-inflammatory action for treating corneal alkali burns in a mouse model

Introduction: Moderate corneal alkali burns such as those sustained from accidental exposure to household chemicals are treated with topical corticosteroids. Side effects include increased intraocular pressure and slowing of wound healing. Here, we compare the effects of a cannabinoid receptor 2 (CB2r) agonist, TA-A001, that is involved in wound healing with that of the corticosteroid, prednisolone. Methods: TA-A001 was encapsulated with a polymeric micelle comprising polyvinylpyrrolidone: polylactide block copolymers referred to as SmartCelle™ to allow delivery of the very hydrophobic drug. Mouse corneas were given moderate alkali burns. Different doses of TA-A001 of 0.125%, 0.25% and 0.5% were used to treat the burns in comparison to the corticosteroid, prednisolone. Results: TA-A001 at 0.25% and 0.5% allowed for faster wound closure. However, the higher 0.5% dose also induced unwanted neovascularization. By comparison, burned corneas treated with prednisolone showed slower healing as well as disorganization of the cornea. Although 0.25% TA-A001 appeared to produce the most-optimal responses, this dose resulted in marked expression of the macrophage chemoattractant protein, MCP-1. However, there was also an increase in CD163 positive stained M2 anti-inflammatory macrophages in the TA-A001 corneas. TA-A001 treated corneas showed the presence of sensory nerve fibers throughout the corneal epithelium including the superficial cell layers as did Substance P staining. Discussion: We found that TA-A001 at the 0.25% doses was able to modulate inflammation resulting from a moderate alkali burn to the cornea. With more extensive testing, TA-A001 might prove to be a potential alternative to corticosteroids for treating alkali burns or other causes of corneal inflammation.

The synthetic cannabinoid 5F-MDMB-PICA enhances the metabolic activity and angiogenesis in human brain microvascular endothelial cells by upregulation of VEGF, ANG-1, and ANG-2

Brain angiogenesis, the formation of new blood vessels from existing brain vasculature, has been previously associated with neural plasticity and addictive behaviors related to substances. Synthetic cannabinoids (SCs) have become increasingly popular due to their ability to mimic the effects of cannabis, offering high potency and easy accessibility. In the current study, we reveal that the SC 5F-MDMB-PICA, the most common SC in the United States in 2019, increases cell metabolic activity and promotes angiogenesis in human brain microvascular endothelial cells (HBMECs). First, we performed an MTT assay to evaluate the effects of 5F-MDMB-PICA treatment at various concentrations (0.0001 μM, 0.001 μM, 0.01 μM, 0.1 μM, and 1 μM) on HBMECs metabolic activity. The results demonstrated higher concentrations of the SC improved cell metabolic activity. Furthermore, 5F-MDMB-PICA treatment enhanced tube formation and migration of HBMECs in a dosage-dependent manner. Additionally, the mRNA, secreted protein, and intracellular protein levels of vascular endothelial growth factor, angiopoietin-1, and angiopoietin-2, which are involved in the regulation of angiogenesis, as well as the protein levels of cannabinoid receptor type-1, were all increased following treatment with 5F-MDMB-PICA. Notably, the phosphorylation levels at Serine 9 residue of glycogen synthase kinase-3β were also increased in the 5F-MDMB-PICA treated HBMECs. Collectively, our findings demonstrate that 5F-MDMB-PICA can enhance angiogenesis in HBMECs, suggesting the significant role of angiogenesis in the response to SCs. Manipulating this interaction may pave the way for innovative treatments targeting SC addiction and angiogenesis-related conditions.

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.

A physiological concentration of anandamide promotes the migration of human endometrial fibroblast and the interaction with endothelial cells invitro

INTRODUCTION

The mechanisms that govern fibroblast behavior during the vascular adaptations of the uterus at early pregnancy remain unknown. Anandamide, an endocannabinoid, binds to cannabinoid receptors (CBs), and regulates gestation and angiogenesis. Its tone is regulated by fatty acid amide hydrolase (FAAH) within the uterus. We investigated the role of anandamide in endometrial fibroblasts migration and whether anandamide modulates fibroblasts-endothelial crosstalk.

METHODS

T-hESC and EA.hy926 cell lines were used as models of endometrial stromal and endothelial cells, respectively. T-hESC were incubated with anandamide plus different agents. Migration was tested (wound healing assay and phalloidin staining). Protein expression and localization were studied by Western blot and immunofluorescence. To test fibroblast-endothelial crosstalk, EA.hy926 cells were incubated with fibroblast conditioned media obtained after T-hESC migration.

RESULTS

Anandamide 1 nM increased T-hESC migration via CB1 and CB2. Cyclooxygenase-2 participated in anandamide-stimulated fibroblast migration. Prostaglandin F2alpha, and not prostaglandin E2, increased fibroblast wound closure. CB1, CB2, cyclooxygenase-2 and FAAH were expressed in T-hESC. Anandamide did not alter cyclooxygenase-2 localization but induced its cytoplasmic and nuclear expression through CB1 and CB2. URB-597, a FAAH selective inhibitor, also increased T-hESC migration via both CBs, and augmented cyclooxygenase-2 expression. Conditioned media from anandamide-induced T-hESC wound healing closure stimulated endothelial migration and did not alter their proliferation. Soluble factors from cyclooxygenase-2 were secreted by T-hESC and participated in T-hESC-induced EA.hy926 migration. Although anandamide-conditioned media augmented in EA.hy926 the expression of γH2AX, a marker of DNA damage, cyclooxygenase-2 was not involved in this effect.

DISCUSSION

Our results provide novel evidence about an active role of anandamide on endometrial fibroblast behavior as a mechanism regulating uterine vascular adaptations in early gestation.

Exploring the Therapeutic Potential of Cannabinoid Receptor Antagonists in Inflammation, Diabetes Mellitus, and Obesity

Recently, research has greatly expanded the knowledge of the endocannabinoid system (ECS) and its involvement in several therapeutic applications. Cannabinoid receptors (CBRs) are present in nearly every mammalian tissue, performing a vital role in different physiological processes (neuronal development, immune modulation, energy homeostasis). The ECS has an essential role in metabolic control and lipid signaling, making it a potential target for managing conditions such as obesity and diabetes. Its malfunction is closely linked to these pathological conditions. Additionally, the immunomodulatory function of the ECS presents a promising avenue for developing new treatments for various types of acute and chronic inflammatory conditions. Preclinical investigations using peripherally restricted CBR antagonists that do not cross the BBB have shown promise for the treatment of obesity and metabolic diseases, highlighting the importance of continuing efforts to discover novel molecules with superior safety profiles. The purpose of this review is to examine the roles of CB1R and CB2Rs, as well as their antagonists, in relation to the above-mentioned disorders.

Therapeutic targeting of the tumor microenvironments with cannabinoids and their analogs: Update on clinical trials

Cancer is a major global public health concern that affects both industrialized and developing nations. Current cancer chemotherapeutic options are limited by side effects, but plant-derived alternatives and their derivatives offer the possibilities of enhanced treatment response and reduced side effects. A plethora of recently published articles have focused on treatments based on cannabinoids and cannabinoid analogs and reported that they positively affect healthy cell growth and reverse cancer-related abnormalities by targeting aberrant tumor microenvironments (TMEs), lowering tumorigenesis, preventing metastasis, and/or boosting the effectiveness of chemotherapy and radiotherapy. Furthermore, TME modulating systems are receiving much interest in the cancer immunotherapy field because it has been shown that TMEs have significant impacts on tumor progression, angiogenesis, invasion, migration, epithelial to mesenchymal transition, metastasis and development of drug resistance. Here, we have reviewed the effective role of cannabinoids, their analogs and cannabinoid nano formulations on the cellular components of TME (endothelial cells, pericytes, fibroblast and immune cells) and how efficiently it retards the progression of carcinogenesis is discussed. The article summarizes the existing research on the molecular mechanisms of cannabinoids regulation of the TME and finally highlights the human studies on cannabinoids' active interventional clinical trials. The conclusion outlines the need for future research involving clinical trials of cannabinoids to demonstrate their efficacy and activity as a treatment/prevention for various types of human malignancies.

TFOS Lifestyle: Impact of lifestyle challenges on the ocular surface

Many factors in the domains of mental, physical, and social health have been associated with various ocular surface diseases, with most of the focus centered on aspects of dry eye disease (DED). Regarding mental health factors, several cross-sectional studies have noted associations between depression and anxiety, and medications used to treat these disorders, and DED symptoms. Sleep disorders (both involving quality and quantity of sleep) have also been associated with DED symptoms. Under the domain of physical health, several factors have been linked to meibomian gland abnormalities, including obesity and face mask wear. Cross-sectional studies have also linked chronic pain conditions, specifically migraine, chronic pain syndrome and fibromyalgia, to DED, principally focusing on DED symptoms. A systematic review and meta-analysis reviewed available data and concluded that various chronic pain conditions increased the risk of DED (variably defined), with odds ratios ranging from 1.60 to 2.16. However, heterogeneity was noted, highlighting the need for additional studies examining the impact of chronic pain on DED signs and subtype (evaporative versus aqueous deficient). With respect to societal factors, tobacco use has been most closely linked to tear instability, cocaine to decreased corneal sensitivity, and alcohol to tear film disturbances and DED symptoms.

Endocannabinoid signaling in glioma

High-grade gliomas constitute the most frequent and aggressive form of primary brain cancer in adults. These tumors express cannabinoid CB₁ and CB₂ receptors, as well as other elements of the endocannabinoid system. Accruing preclinical evidence supports that pharmacological activation of cannabinoid receptors located on glioma cells exerts overt anti-tumoral effects by modulating key intracellular signaling pathways. The mechanism of this cannabinoid receptor-evoked anti-tumoral activity in experimental models of glioma is intricate and may involve an inhibition not only of cancer cell survival/proliferation, but also of invasiveness, angiogenesis, and the stem cell-like properties of cancer cells, thereby affecting the complex tumor microenvironment. However, the precise biological role of the endocannabinoid system in the generation and progression of glioma seems very context-dependent and remains largely unknown. Increasing our basic knowledge on how (endo)cannabinoids act on glioma cells could help to optimize experimental cannabinoid-based anti-tumoral therapies, as well as the preliminary clinical testing that is currently underway.

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

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

The Synthetic Cannabinoid URB447 Exerts Antitumor and Antimetastatic Effect in Melanoma and Colon Cancer

The endocannabinoid system is widespread through the body and carries out a wide variety of functions. However, its involvement in other pathologies, such as cancer, still needs further attention. We aim to investigate the role of CB2 receptor during melanoma and colorectal cancer (CRC) aggressiveness and metastatic growth in the liver. We used the synthetic cannabinoid URB447, a known CB2 agonist and CB1 antagonist drug, and studied prometastatic ability of mouse B16 melanoma and MCA38 CRC cells, by means of proliferation, apoptosis, cell cycle, migration and matrix degradation in vitro upon URB447 treatment. We reported a dose-dependent viability decrease in both tumor types. This result is partly mediated by apoptotic cell death and cell cycle arrest in G1/G0 phase, as observed through flow cytometry. Melanoma and CRC cell migration was affected in a dose-dependent fashion as observed through scratch assay, whereas the secretion of matrix degrading proteins metalloprotease 2 (MMP2) and 9 (MMP9) in tumor cells did not significantly change. Moreover, daily treatment of tumor bearing mice with URB447 decreased the development of liver metastasis in a melanoma model in vivo. This proof of concept study points out to the synthetic cannabinoid URB447 as a potential candidate for deeper studies to confirm its potential as antitumor therapy and liver metastasis treatment for CRC and melanoma.

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 Suppresses Angiogenesis and Stemness of Breast Cancer Cells by Downregulation of Hypoxia-Inducible Factors-1α

Simple Summary

Cannabidiol (CBD), one of the compounds present in the marijuana plant, has antitumor properties. However, the effect of CBD on breast cancer remains unclear. The aim of this study was to assess the effects of CBD for the angiogenesis and stemness of breast cancer cells by decreasing the expression of hypoxia-induced factor-1α (HIF-1α) through the Src/von Hippel–Lindau tumor suppressor protein (VHL) interaction. CBD can suppress angiogenesis and stem cell-like properties of breast cancer through Src/VHL/HIF-1α signaling.

Abstract

To assess the effect of Cannabidiol (CBD) on the angiogenesis and stemness of breast cancer cells as well as proliferation. Methods: mRNA level and the amount of protein of vascular endothelial growth factor (VEGF) were determined by qRT-PCR and ELISA. The angiogenic potential of breast cancer cells under hypoxic conditions was identified by the HUVEC tube formation assay. The degradation of HIF-1α by CBD and the Src/von Hippel–Lindau tumor suppressor protein (VHL) interaction were assessed by a co-immunoprecipitation assay and Western blotting. To identify the stemness of mamospheres, they were evaluated by the sphere-forming assay and flow cytometry. Results: CBD can suppress angiogenesis and stem cell-like properties of breast cancer through Src/VHL/HIF-1α signaling. CBD may potentially be utilized in the treatment of refractory or recurrent breast cancer.

Implications of dysregulated endogenous cannabinoid family members in the pathophysiology of endometriosis

OBJECTIVE

To determine the involvement of the endocannabinoid (EC) family member in the pathophysiology of endometriosis (EMS).

DESIGN

Mass spectrometry analysis of plasma and tissue samples from patients with EMS, controls, and a mouse model of EMS and messenger RNA and immunohistochemistry analysis of the samples from patients with EMS and controls.

SETTING

Academic teaching hospital and university.

PATIENT(S)

Patients with EMS and healthy fertile control subjects.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Endocannabinoid analysis in patient plasma, EMS lesions, and healthy endometrial samples.

RESULT(S)

Circulating ECs were detected in the plasma samples, whereas no significant changes were observed in patients with EMS compared with healthy fertile controls. However, the palmitoylethanolamide levels were significantly higher in the EMS lesions than in the endometrium from patients with EMS. Similarly, genes involved in the EC signaling pathways were differentially expressed in the EMS lesions. Analysis of cannabinoid 1 and 2 receptors in the EMS lesions revealed a significantly lower cannabinoid 2 receptor expression, whereas no significant changes were observed in cannabinoid 1 receptor expression compared with those in the endometrium from both patients with EMS and healthy fertile controls. The palmitoylethanolamide levels were significantly elevated in plasma from EMS mice compared with that from sham controls and in EMS lesions compared with uterine samples.

CONCLUSION(S)

Together, we provide evidence toward dysregulation of members of the ECs in both patients with EMS and the mouse model of EMS. These findings will advance the knowledge of the role of ECs in EMS and their potential implications as therapeutic targets.

Activation of cannabinoid receptor 2 alleviates glucocorticoid-induced osteonecrosis of femoral head with osteogenesis and maintenance of blood supply

In glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH), downregulated osteogenic ability and damaged blood supply are two key pathogenic mechanisms. Studies suggested that cannabinoid receptor 2 (CB2) is expressed in bone tissue and it plays a positive role in osteogenesis. However, whether CB2 could enhance bone formation and blood supply in GC-induced ONFH remains unknown. In this study, we focused on the effect of CB2 in GC-induced ONFH and possible mechanisms in vitro and in vivo. By using GC-induced ONFH rat model, rat-bone mesenchymal stem cells (BMSCs) and human umbilical vein endothelial cells (HUVECs) to address the interaction of CB2 in vitro and in vivo, we evaluate the osteogenic and angiogenic effect variation and possible mechanisms. Micro-CT, histological staining, angiography, calcein labeling, Alizarin red staining (ARS), alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP) staining, TUNEL staining, migration assay, scratch assay, and tube formation were applied in this study. Our results showed that selective activation of CB2 alleviates GC-induced ONFH. The activation of CB2 strengthened the osteogenic activity of BMSCs under the influence of GCs by promotion of GSK-3β/β-catenin signaling pathway. Furthermore, CB2 promoted HUVECs migration and tube-forming capacities. Our findings indicated that CB2 may serve as a rational new treatment strategy against GC-induced ONFH by osteogenesis activation and maintenance of blood supply.

The strengths and limits of cannabinoids and their receptors in cancer: Insights into the role of tumorigenesis-underlying mechanisms and therapeutic aspects

Cancer, as a mysterious and complex disease, has a multi-stage molecular process that uses the cellular molecular machine and multiple signaling pathways to its advantage. Cannabinoids, as terpenophenolic compounds and their derivatives, showed influences on immune system responses, inflammation, and cell growth that have sparked a growing interest in exploring their effects on cancer cell fate, as well. A large body of evidence in experimental models indicating the involvement of cannabinoids and their related receptors in cancer cell growth, development, and fate. In accordance, the present study provided insights regarding the strengths and limits of cannabinoids and their receptors in critical steps of tumorigenesis and its underlying molecular pathways such as; cancer cell proliferation, type of cell death pathway, angiogenesis, invasion, metastasis and, immune system response. Based on the results of the present study and due to the contribution of cannabinoids in various cancer cell growth control processes, these compounds cancer can be considered worthwhile in finding new alternatives for cancer therapy.

Inhibition of Vascular Growth by Modulation of the Anandamide/Fatty Acid Amide Hydrolase Axis

Supplemental Digital Content is available in the text.

Objective:

Pathological angiogenesis is a hallmark of various diseases characterized by local hypoxia and inflammation. These disorders can be treated with inhibitors of angiogenesis, but current compounds display a variety of side effects and lose efficacy over time. This makes the identification of novel signaling pathways and pharmacological targets involved in angiogenesis a top priority.

Approach and Results:

Here, we show that inactivation of FAAH (fatty acid amide hydrolase), the enzyme responsible for degradation of the endocannabinoid anandamide, strongly impairs angiogenesis in vitro and in vivo. Both, the pharmacological FAAH inhibitor URB597 and anandamide induce downregulation of gene sets for cell cycle progression and DNA replication in endothelial cells. This is underscored by cell biological experiments, in which both compounds inhibit proliferation and migration and evoke cell cycle exit of endothelial cells. This prominent antiangiogenic effect is also of pathophysiological relevance in vivo, as laser-induced choroidal neovascularization in the eye of FAAH^−/− mice is strongly reduced.

Conclusions:

Thus, elevation of endogenous anandamide levels by FAAH inhibition represents a novel antiangiogenic mechanism.

Repurposing Cannabidiol as a Potential Drug Candidate for Anti-Tumor Therapies

In recent years, evidence has accumulated that cannabinoids-especially the non-psychoactive compound, cannabidiol (CBD)-possess promising medical and pharmacological activities that might qualify them as potential anti-tumor drugs. This review is based on multiple studies summarizing different mechanisms for how CBD can target tumor cells including cannabinoid receptors or other constituents of the endocannabinoid system, and their complex activation of biological systems that results in the inhibition of tumor growth. CBD also participates in anti-inflammatory activities which are related to tumor progression, as demonstrated in preclinical models. Although the numbers of clinical trials and tested tumor entities are limited, there is clear evidence that CBD has anti-tumor efficacy and is well tolerated in human cancer patients. In summary, it appears that CBD has potential as a neoadjuvant and/or adjuvant drug in therapy for cancer.

The role of peptidase neurolysin in neuroprotection and neural repair after stroke

Current experimental stroke research has evolved to focus on detailed understanding of the brain’s self-protective and restorative mechanisms, and harness this knowledge for development of new therapies. In this context, the role of peptidases and neuropeptides is of growing interest. In this focused review, peptidase neurolysin (Nln) and its extracellular peptide substrates are briefly discussed in relation to pathophysiology of ischemic stroke. Upregulation of Nln following stroke is viewed as a compensatory cerebroprotective mechanism in the acute phase of stroke, because the main neuropeptides inactivated by Nln are neuro/cerebrotoxic (bradykinin, substance P, neurotensin, angiotensin II, hemopressin), whereas the peptides generated by Nln are neuro/cerebroprotective (angiotensin-(1–7), Leu-/Met-enkephalins). This notion is confirmed by experimental studies documenting aggravation of stroke outcomes in mice after inhibition of Nln following stroke, and dramatic improvement of stroke outcomes in mice overexpressing Nln in the brain. The role of Nln in the (sub)chronic phase of stroke is less clear and it is likely, that this peptidase does not have a major role in neural repair mechanisms. This is because, the substrates of Nln are less uniform in modulating neurorestorative mechanisms in one direction, some appearing to have neural repair enhancing/stimulating potential, whereas others doing the opposite. Future studies focusing on the role of Nln in pathophysiology of stroke should determine its potential as a cerebroprotective target for stroke therapy, because its unique ability to modulate multiple neuropeptide systems critically involved in brain injury mechanisms is likely advantageous over modulation of one pathogenic pathway for stroke pharmacotherapy.

CannabinEYEds: The Endocannabinoid System as a Regulator of the Ocular Surface Nociception, Inflammatory Response, Neovascularization and Wound Healing

The endocannabinoid system (ECS) is a complex regulatory system, highly conserved among vertebrates. It has been widely described in nearly all human tissues. In the conjunctiva and cornea, the ECS is believed to play a pivotal role in the modulation of the local inflammatory state as well as in the regulation of tissue repair and fibrosis, neo-angiogenesis and pain perception. This review aims to summarize all the available data on ECS expression and its function in ocular surface structures to provide a specific insight concerning its modulation in dry eye disease, and to propose directions for future research.

Assessment of chromosomal aberrations among agricultural workers exposed to pesticides in Punjab, India

Chromosomal aberrations (CAs) are an important tool for assessment of exposure to pesticides. Genotoxic potential of pesticides is a principal risk factor for long-term health effects. The present study was aimed toward the assessment of CAs among agricultural workers exposed to pesticides and comparison with nonagricultural workers not exposed to pesticides. A total of 296 subjects were enrolled in the study: exposed (n = 148) and nonexposed subjects (n = 148) from Punjab. A significantly high frequency of aberrations was seen in peripheral blood lymphocytes of exposed subjects as compared with nonexposed ones. Most CAs were present as loss (aneuploidy) and were observed significantly in subjects having a history of alcohol consumption. It can be, thus, concluded that agricultural workers exposed to a mixture of pesticides, in addition to being alcoholic, are at a greater risk of genotoxic damage. It is highly recommended that the agricultural workers are educated regarding the potential hazards of occupational exposure to pesticides.

ERK and Akt exhibit distinct signaling responses following stimulation by pro-angiogenic factors

Background

Angiogenesis plays an important role in the survival of tissues, as blood vessels provide oxygen and nutrients required by the resident cells. Thus, targeting angiogenesis is a prominent strategy in many different settings, including both tissue engineering and cancer treatment. However, not all of the approaches that modulate angiogenesis lead to successful outcomes. Angiogenesis-based therapies primarily target pro-angiogenic factors such as vascular endothelial growth factor-A (VEGF) or fibroblast growth factor (FGF) in isolation, and there is a limited understanding of how these promoters combine together to stimulate angiogenesis. Targeting one pathway could be insufficient, as alternative pathways may compensate, diminishing the overall effect of the treatment strategy.

Methods

To gain mechanistic insight and identify novel therapeutic strategies, we have developed a detailed mathematical model to quantitatively characterize the crosstalk of FGF and VEGF intracellular signaling. The model focuses on FGF- and VEGF-induced mitogen-activated protein kinase (MAPK) signaling to promote cell proliferation and the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway, which promotes cell survival and migration. We fit the model to published experimental datasets that measure phosphorylated extracellular regulated kinase (pERK) and Akt (pAkt) upon FGF or VEGF stimulation. We validate the model with separate sets of data.

Results

We apply the trained and validated mathematical model to characterize the dynamics of pERK and pAkt in response to the mono- and co-stimulation by FGF and VEGF. The model predicts that for certain ranges of ligand concentrations, the maximum pERK level is more responsive to changes in ligand concentration compared to the maximum pAkt level. Also, the combination of FGF and VEGF indicates a greater effect in increasing the maximum pERK compared to the summation of individual effects, which is not seen for maximum pAkt levels. In addition, our model identifies the influential species and kinetic parameters that specifically modulate the pERK and pAkt responses, which represent potential targets for angiogenesis-based therapies.

Conclusions

Overall, the model predicts the combination effects of FGF and VEGF stimulation on ERK and Akt quantitatively and provides a framework to mechanistically explain experimental results and guide experimental design. Thus, this model can be utilized to study the effects of pro- and anti-angiogenic therapies that particularly target ERK and/or Akt activation upon stimulation with FGF and VEGF.

Effects of the synthetic cannabinoid XLR-11 on the viability and migration rates of human brain microvascular endothelial cells in a clinically-relevant model

BACKGROUND

Synthetic cannabinoids (SCs) are a group of newly-developed drugs that bind and activate endocannabinoid system receptors. Angiogenesis is a biological process in which new blood vessels are formed from preexistent blood vessels. It plays a vital role in tissue growth, wound healing, and embryogenesis. This study aims to investigate the effects of the synthetic cannabinoid XLR-11 on specific cellular functions such as viability and angiogenesis in vitro.

METHODS

Human brain microvascular endothelial cells (HBMECs) were cultured in DMEM/F12 medium supplemented with an endothelial cell growth kit. The MTT assay was used to investigate the viability of endothelial cells. An endothelial cell migration assay was used to investigate migration ability, while a tube formation assay was used to investigate the angiogenic capacity of the endothelial cells.

RESULTS

XLR-11 was found to enhance the viability of HBMECs. Moreover, the migration rate and angiogenic capacity significantly increased in the presence of various concentrations of XLR-11 compared to the control.

CONCLUSION

The current study shows that XLR-11 increases the viability of human brain microvascular endothelial cells and enhances angiogenesis in the brain in vitro, suggesting that XLR-11 could potentially be used as a therapeutic angiogenic drug in human brain injury treatment.

CB1 Cannabinoid Receptors Stimulate Gβγ-GRK2-Mediated FAK Phosphorylation at Tyrosine 925 to Regulate ERK Activation Involving Neuronal Focal Adhesions

CB₁ cannabinoid receptors (CB₁) are abundantly expressed in the nervous system where they regulate focal adhesion kinase (FAK) and the mitogen-activated protein kinases (MAPK) extracellular signal-regulated kinase 1 and 2 (ERK1/2). However, the role of CB₁-stimulated FAK 925 tyrosine phosphorylation (Tyr-P) in regulating ERK1/2 activation remains undefined. Here, immunoblotting analyses using antibodies against FAK phospho-Tyr 925 and ERK2 phospho-Tyr 204 demonstrated CB₁-stimulated FAK 925 Tyr-P and ERK2 204 Tyr-P (0–5 min) which was followed by a decline in Tyr-P (5–20 min). CB₁ stimulated FAK-Grb2 association and Ras-mediated ERK2 activation. The FAK inhibitors Y11 and PF 573228 abolished FAK 925 Tyr-P and partially inhibited ERK2 204 Tyr-P. FAK 925 Tyr-P and ERK2 204 Tyr-P were adhesion-dependent, required an intact actin cytoskeleton, and were mediated by integrins, Flk-1 vascular endothelial growth factor receptors, and epidermal growth factor receptors. FAK 925 Tyr-P and ERK2 204 Tyr-P were blocked by the Gβγ inhibitor gallein, a GRK2 inhibitor, and GRK2 siRNA silencing, suggesting Gβγ and GRK2 participate in FAK-mediated ERK2 activation. Together, these studies indicate FAK 925 Tyr-P occurs concurrently with CB₁-stimulated ERK2 activation and requires the actin cytoskeleton and G_i/oβγ-GRK2-mediated cross-talk between CB₁, integrins, and receptor tyrosine kinases (RTKs).

Cannabis and the Cornea

Purpose: While cannabis has the potential to reduce corneal pain, cannabinoids might induce side effects. This review article examines the effects of cannabinoids on the cornea. As more states and countries consider the legalization of adult cannabis use, health-care providers will need to identify ocular effects of cannabis consumption.Methods: Studies included in this review examined the connection between cannabis and the cornea, more specifically anti-nociceptive and anti-inflammatory actions of cannabinoids. NCBI Databases from 1781 up to December 2019 were consulted.Results: Five studies examined corneal dysfunctions caused by cannabis consumption (opacification, decreased endothelial cell density). Twelve studies observed a reduction in corneal pain and inflammation (less lymphocytes, decreased corneal neovascularization, increased cell proliferation and migration).Conclusion: More than half of the studies examined the therapeutic effects of cannabinoids on the cornea. As the field is still young, more studies should be conducted to develop safe cannabinoid treatments for corneal diseases.

Activation of cannabinoid receptors promote periodontal cell adhesion and migration

OBJECTIVE

Medical and recreational cannabis use is increasing significantly, but its impacts on oral health remain unclear. The aim of this study is to investigate the effects of tetrahydrocannabinol (THC), the major active component in cannabis, on periodontal fibroblast cell adhesion and migration to explore its role in periodontal regeneration and wound healing.

MATERIAL AND METHODS

The different distribution of cannabinoid receptors 1 (CB1) and 2 (CB2) was characterized in the mouse periodontium. Human periodontal fibroblast cell (HPLF) adhesion and migration was analysed by in vitro wound healing assay with and without THC. The focal adhesion kinase (FAK) signalling pathway was investigated to uncover the underlying cellular mechanism. The receptor dependency of cannabinoid effects was examined by using selective antagonists to block THC.

RESULTS

Both CB1 and CB2 were expressed in periodontal tissues but with different expression patterns. Tetrahydrocannabinol promoted periodontal cell wound healing by inducing HPLF cell adhesion and migration. This was mediated by focal adhesion kinase (FAK) activation and its modulation of MAPK activities. The effect of cannabinoids on periodontal fibroblast cell adhesion and migration was mainly dependent on the CB2.

CONCLUSION

These results suggested that cannabinoids may contribute to developing new therapeutics for periodontal regeneration and wound healing.

Anti-tumour actions of cannabinoids

The endocannabinoid system has emerged as an important target for the treatment of many diverse diseases. In addition to the well-established palliative effects of cannabinoids in cancer therapy, phytocannabinoids, synthetic cannabinoid compounds and inhibitors of endocannabinoid degradation have attracted attention as possible systemic anticancer drugs. Results emerging from preclinical studies suggest cannabinoids elicit effects at different levels of cancer progression, including inhibition of proliferation, neovascularization, invasion and chemoresistance, induction of apoptosis and autophagy as well as enhancement of tumour immune surveillance. Although the clinical use of cannabinoid receptor ligands is limited by their psychoactivity, non-psychoactive compounds, such as cannabidiol, have gained attention due to preclinically established anticancer properties and a favourable risk-to-benefit profile. Thus, cannabinoids may complement the currently used collection of chemotherapeutic agents, as a broadly diversified option for cancer treatment, while counteracting some of their severe side effects. LINKED ARTICLES: This article is part of a themed section on 8th European Workshop on Cannabinoid Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.10/issuetoc.

Decreased Expression of Cannabinoid Receptors in the Eutopic and Ectopic Endometrium of Patients with Adenomyosis

Objective

Adenomyosis is a common gynecologic benign disease that may have a life-long negative impact on women. Previous studies have indicated that the endocannabinoid system may participate in the progress of endometriosis. Our research aims to analyze the expression patterns of the typical cannabinoid receptors (CB1 and CB2), the main constituents of the endocannabinoid system, in endometrial samples derived from patients diagnosed as adenomyosis or not.

Methods

Eutopic and corresponding ectopic endometrium from 45 premenopausal women diagnosed as adenomyosis and normal endometrium from 34 age-matched women lacking evidence of adenomyosis were examined by immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR) to determine the CB1 and CB2 expression levels.

Results

In either the proliferative or the secretory phase, CB1 and CB2 protein and mRNA levels were both significantly lower in the eutopic and ectopic endometrium of adenomyosis when compared with normal endometrium. For women with adenomyosis, CB1 and CB2 protein and mRNA levels were much lower in the ectopic endometrium than the eutopic in both phases of the cycle. Both CB1 and CB2 protein and mRNA levels were increased during the secretory phase in normal endometrium, while CB1 lost its cyclic variation in the eutopic and ectopic endometrium from patients diagnosed as adenomyosis.

Conclusion

The decreased expression of CB1 and CB2 in the eutopic and ectopic endometrium from patients diagnosed as adenomyosis suggests that cannabinoid receptors may participate in the pathogenesis of adenomyosis.

Cannabinoids and Cardiovascular System

Cannabinoids influence cardiovascular variables in health and disease via multiple mechanisms. The chapter covers the impact of cannabinoids on cardiovascular function in physiology and pathology and presents a critical analysis of the proposed signalling pathways governing regulation of cardiovascular function by endogenously produced and exogenous cannabinoids. We know that endocannabinoid system is overactivated under pathological conditions and plays both a protective compensatory role, such as in some forms of hypertension, atherosclerosis and other inflammatory conditions, and a pathophysiological role, such as in disease states associated with excessive hypotension. This chapter focuses on the mechanisms affecting hemodynamics and vasomotor effects of cannabinoids in health and disease states, highlighting mismatches between some studies. The chapter will first review the effects of marijuana smoking on cardiovascular system and then describe the impact of exogenous cannabinoids on cardiovascular parameters in humans and experimental animals. This will be followed by analysis of the impact of cannabinoids on reactivity of isolated vessels. The article critically reviews current knowledge on cannabinoid induction of vascular relaxation by cannabinoid receptor-dependent and -independent mechanisms and dysregulation of vascular endocannabinoid signaling in disease states.

Targeting corneal inflammation by gene therapy: Emerging strategies for keratitis

Inflammation is the underlying process of several diseases within the eye, specifically in the cornea. Current treatment options for corneal inflammation or keratitis, and related neovascularization, are restricted by limited efficacy, adverse effects, and short duration of action. Gene therapy has shown great potential for the treatment of diseases affecting the ocular surface, and major efforts are being targeted to inflammatory mediators and neovascularization, in order to develop potential treatments for corneal inflammation. Gene therapy to treat ocular disorders is still starting, and current therapies are primarily experimental, with most human clinical trials still in research state, although some of them have already shown encouraging results. In this review, we focus on the progress and challenges of gene therapy to treat corneal inflammation. After introducing the inflammation process, we present the main nucleic acid delivery systems, including viral and non-viral vectors, and the most studied strategies to address the therapy: control of neovascularization and regulation of pro- and anti-inflammatory cytokines.

Insights into the effects of the endocannabinoid system in cancer: a review

In the last few decades, the endocannabinoid system has attracted a great deal of interest in terms of its applications to clinical medicine. In particular, its applications in cancer probably represent one of the therapeutic areas with most promise. On the one hand, expression of the endocannabinoid system is altered in numerous types of tumours, compared to healthy tissue, and this aberrant expression has been related to cancer prognosis and disease outcome, suggesting a role of this system in tumour growth and progression that depends on cancer type. On the other hand, cannabinoids exert an anticancer activity by inhibiting the proliferation, migration and/or invasion of cancer cells and also tumour angiogenesis. However, some cannabinoids, at lower concentrations, may increase tumour proliferation, inducing cancer growth. Enough data has been provided to consider the endocannabinoid system as a new therapeutic target in cancer, although further studies to fully establish the effect of cannabinoids on tumour progression are still needed.

Inhibition of Wnt/β-Catenin pathway and Histone acetyltransferase activity by Rimonabant: a therapeutic target for colon cancer

In a high percentage (≥85%) of both sporadic and familial adenomatous polyposis forms of colorectal cancer (CRC), the inactivation of the APC tumor suppressor gene initiates tumor formation and modulates the Wnt/β-Catenin transduction pathways involved in the control of cell proliferation, adhesion and metastasis. Increasing evidence showed that the endocannabinoids control tumor growth and progression, both in vitro and in vivo. We evaluated the effect of Rimonabant, a Cannabinoid Receptor 1 (CB1) inverse agonist, on the Wnt/β-Catenin pathway in HCT116 and SW48 cell lines carrying the genetic profile of metastatic CRC poorly responsive to chemotherapies. In these models, Rimonabant inhibited the Wnt/β-Catenin canonical pathway and increased β-Catenin phosphorylation; in HCT116 cells, but not in SW48, the compound also triggered the Wnt/β-Catenin non canonical pathway activation through induction of Wnt5A and activation of CaMKII. The Rimonabant-induced downregulation of Wnt/β-Catenin target genes was partially ascribable to a direct inhibition of p300/KAT3B histone acetyltransferase, a coactivator of β-Catenin dependent gene regulation. Finally, in HCT116 xenografts, Rimonabant significantly reduced tumor growth and destabilized the nuclear localization of β-Catenin. Obtained data heavily supported the rationale for the use of cannabinoids in combined therapies for metastatic CRC harbouring activating mutations of β-Catenin.

Cannabinoids as Anticancer Drugs

The endocannabinoid system encompassing cannabinoid receptors, endogenous receptor ligands (endocannabinoids), as well as enzymes conferring the synthesis and degradation of endocannabinoids has emerged as a considerable target for pharmacotherapeutical approaches of numerous diseases. Besides palliative effects of cannabinoids used in cancer treatment, phytocannabinoids, synthetic agonists, as well as substances that increase endogenous endocannabinoid levels have gained interest as potential agents for systemic cancer treatment. Accordingly, cannabinoid compounds have been reported to inhibit tumor growth and spreading in numerous rodent models. The underlying mechanisms include induction of apoptosis, autophagy, and cell cycle arrest in tumor cells as well as inhibition of tumor cell invasion and angiogenic features of endothelial cells. In addition, cannabinoids have been shown to suppress epithelial-to-mesenchymal transition, to enhance tumor immune surveillance, and to support chemotherapeutics' effects on drug-resistant cancer cells. However, unwanted side effects include psychoactivity and possibly pathogenic effects on liver health. Other cannabinoids such as the nonpsychoactive cannabidiol exert a comparatively good safety profile while exhibiting considerable anticancer properties. So far experience with anticarcinogenic effects of cannabinoids is confined to in vitro studies and animal models. Although a bench-to-bedside conversion remains to be established, the current knowledge suggests cannabinoid compounds to serve as a group of drugs that may offer significant advantages for patients suffering from cancer diseases. The present review summarizes the role of the endocannabinoid system and cannabinoid compounds in tumor progression.

Cannabidiol: State of the art and new challenges for therapeutic applications

Over the past years, several lines of evidence support a therapeutic potential of Cannabis derivatives and in particular phytocannabinoids. Δ⁹-THC and cannabidiol (CBD) are the most abundant phytocannabinoids in Cannabis plants and therapeutic application for both compounds have been suggested. However, CBD is recently emerging as a therapeutic agent in numerous pathological conditions since devoid of the psychoactive side effects exhibited instead by Δ⁹-THC. In this review, we highlight the pharmacological activities of CBD, its cannabinoid receptor-dependent and -independent action, its biological effects focusing on immunomodulation, angiogenetic properties, and modulation of neuronal and cardiovascular function. Furthermore, the therapeutic potential of cannabidiol is also highlighted, in particular in nuerological diseases and cancer.

Pharmacological inhibition of MAGL attenuates experimental colon carcinogenesis

Colorectal cancer (CRC) is a major health problem in Western countries. The endocannabinoid 2-arachidonoyl-glycerol (2-AG) exerts antiproliferative actions in a number of tumoral cell lines, including CRC cells. Monoacylglycerol lipase (MAGL), a serine hydrolase that inactivates 2-AG, is highly expressed in aggressive human cancer cells. Here, we investigated the role of MAGL in experimental colon carcinogenesis. The role of MAGL was assessed in vivo by using the xenograft and the azoxymethane models of colon carcinogenesis; MAGL expression was evaluated by RT-PCR and immunohistochemistry; 2-AG levels were measured by liquid chromatography mass spectrometry; angiogenesis was evaluated in tumor tissues [by microvessel counting and by investigating the expression of vascular endothelial growth factor (VEGF) and fibroblast growth factor-2 (FGF-2) proteins] as well as in human umbilical vein endothelial cells (HUVEC); cyclin D1 was evaluated by RT-PCR. MAGL and 2-AG were strongly expressed in tumor tissues. The MAGL inhibitor URB602 reduced xenograft tumor volume, this effect being associated to down-regulation of VEGF and FGF-2, reduction in the number of vessels and down-regulation of cyclin D1. In HUVEC, URB602 exerted a direct antiangiogenic effect by inhibiting FGF-2 induced proliferation and migration, and by modulating pro/anti-angiogenic agents. In experiments aiming at investigating the role of MAGL in chemoprevention, URB602 attenuated azoxymethane-induced preneoplastic lesions, polyps and tumors. MAGL, possibly through modulation of angiogenesis, plays a pivotal role in experimental colon carcinogenesis. Pharmacological inhibition of MAGL could represent an innovative therapeutic approach to reduce colorectal tumor progression.

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.

Antitumorigenic targets of cannabinoids - current status and implications

INTRODUCTION

Molecular structures of the endocannabinoid system have gained interest as potential pharmacotherapeutical targets for systemic cancer treatment.

AREAS COVERED

The present review covers the contribution of the endocannabinoid system to cancer progression. Particular focus will be set on the accumulating preclinical data concerning antimetastatic, anti-invasive and anti-angiogenic mechanisms induced by cannabinoids.

EXPERT OPINION

The main goal of targeting endocannabinoid structures for systemic anticancer treatment is the comparatively good safety profile of cannabinoid compounds. In addition, antitumorigenic mechanisms of cannabinoids are not restricted to a single molecular cascade but involve multiple effects on various levels of cancer progression such as angiogenesis and metastasis. Particularly the latter effect has gained interest for pharmacological interventions. Thus, drugs aiming at the endocannabinoid system may represent potential 'antimetastatics' for an upgrade of a future armamentarium against cancer diseases.

Cannabinoid receptor CB1 regulates STAT3 activity and its expression dictates the responsiveness to SR141716 treatment in human glioma patients' cells

Herein we show that a majority of human brain tumor samples and cell lines over-expressed cannabinoid receptor CB1 as compared to normal human astrocytes (NHA), while uniformly expressed low levels of CB2. This finding prompted us to investigate the therapeutic exploitation of CB1 inactivation by SR141716 treatment, with regard to its direct and indirect cell-mediated effects against gliomas. Functional studies, using U251MG glioma cells and primary tumor cell lines derived from glioma patients expressing different levels of CB1, highlighted SR141716 efficacy in inducing apoptosis via G1 phase stasis and block of TGF-β1 secretion through a mechanism that involves STAT3 inhibition. According to the multivariate role of STAT3 in the immune escape too, interestingly SR141716 lead also to the functional and selective expression of MICA/B on the surface of responsive malignant glioma cells, but not on NHA. This makes SR141716 treated-glioma cells potent targets for allogeneic NK cell-mediated recognition through a NKG2D restricted mechanism, thus priming them for NK cell antitumor reactivity. These results indicate that CB1 and STAT3 participate in a new oncogenic network in the complex biology of glioma and their expression levels in patients dictate the efficacy of the CB1 antagonist SR141716 in multimodal glioma destruction.

Role of endocannabinoids in the progression of diabetic retinopathy

In the past decades, the role of numerous factors in the pathophysiology of diabetic retinopathy has been explored, following which marked progress has been made in developing several novel therapeutic options, such as anti-vascular endothelial growth factor, anti-tumor necrosis factor-alpha and various other anti-inflammatory and anti-angiogenic agents, for the treatment of diabetic retinopathy. However, the involvement of endocannabinoid system in its pathogenesis has not been much explored. This review aims at unveiling every aspect of association of the endocannabinoid system and its interactions with various physiological and pathological pathways to induce disease progression. The various alterations induced by endocannabinoids, such as anandamide and 2-arachidonylglycerol, in retina during hyperglycaemia clearly demonstrate and verify their involvement in aggravating the pathological conditions, hence leading to the progression of diabetic retinopathy. Exploring this involvement furthermore, in greater depths, might be beneficial in acknowledging and understanding the hidden aspects of the pathogenesis of this complication even better and might provide a therapeutically beneficial alternative target to combat and restrict its progression amongst diabetic patients.

Anandamide drives cell cycle progression through CB1 receptors in a rat model of synchronized liver regeneration

The endocannabinoid system, through cannabinoid receptor signaling by endocannabinoids, is involved in a wide range of functions and physiopathological conditions. To date, very little is known concerning the role of the endocannabinoids in the control and regulation of cell proliferation. An anti-proliferative action of CB1 signaling blockade in neurogenesis and angiogenesis argues in favor of proliferation-promoting functions of endocannabinoids through CB1 receptors when pro-growth signals are present. Furthermore, liver regeneration, a useful in vivo model of synchronized cell proliferation, is characterized by a peak of anandamide that elicits through CB1 receptor, the expression of critical mitosis genes. The aim of this study was to focus on the timing of endocannabinoid signaling changes during the different phases of the cell cycle, exploiting the rat liver regeneration model following partial hepatectomy, the most useful to study synchronized cell cycle in vivo. Hepatic regeneration led to increased levels of anandamide and endocannabinoid-like molecules oleoylethanolamide (OEA) and palmitoylethanolamide (PEA) in the G1 phase of the cell cycle, with a concomitant increase in CB1 mRNA levels, whose protein expression peaked later during the S phase. Blocking of CB1 receptor with a low dose of the selective antagonist/inverse agonist SR141716 (0.7 mg/kg/dose) affected cell cycle progression reducing the expression of PCNA, and through the inhibition of pERK and pSTAT3 pathways. These results support the notion that the signaling mediated by anandamide through CB1 receptor may be important for the entry and progression of cells into the cell cycle and hence for their proliferation under mitogenic signals.

Fetal endocannabinoids orchestrate the organization of pancreatic islet microarchitecture

Endocannabinoids are implicated in the control of glucose utilization and energy homeostasis by orchestrating pancreatic hormone release. Moreover, in some cell niches, endocannabinoids regulate cell proliferation, fate determination, and migration. Nevertheless, endocannabinoid contributions to the development of the endocrine pancreas remain unknown. Here, we show that α cells produce the endocannabinoid 2-arachidonoylglycerol (2-AG) in mouse fetuses and human pancreatic islets, which primes the recruitment of β cells by CB1 cannabinoid receptor (CB1R) engagement. Using subtractive pharmacology, we extend these findings to anandamide, a promiscuous endocannabinoid/endovanilloid ligand, which impacts both the determination of islet size by cell proliferation and α/β cell sorting by differential activation of transient receptor potential cation channel subfamily V member 1 (TRPV1) and CB1Rs. Accordingly, genetic disruption of TRPV1 channels increases islet size whereas CB1R knockout augments cellular heterogeneity and favors insulin over glucagon release. Dietary enrichment in ω-3 fatty acids during pregnancy and lactation in mice, which permanently reduces endocannabinoid levels in the offspring, phenocopies CB1R(-/-) islet microstructure and improves coordinated hormone secretion. Overall, our data mechanistically link endocannabinoids to cell proliferation and sorting during pancreatic islet formation, as well as to life-long programming of hormonal determinants of glucose homeostasis.

Identification of prostamides, fatty acyl ethanolamines, and their biosynthetic precursors in rabbit cornea

Arachidonoyl ethanolamine (anandamide) and pros-taglandin ethanolamines (prostamides) are biologically active derivatives of arachidonic acid. Although available through different precursor phospholipids, there is considerable overlap between the biosynthetic pathways of arachidonic acid-derived eicosanoids and anandamide-derived prostamides. Prostamides exhibit physiological actions and are involved in ocular hypotension, smooth muscle contraction, and inflammatory pain. Although topical application of bimatoprost, a structural analog of prostaglandin F2α ethanolamide (PGF2α-EA), is currently a first-line treatment for ocular hypertension, the endogenous production of prostamides and their biochemical precursors in corneal tissue has not yet been reported. In this study, we report the presence of anandamide, palmitoyl-, stearoyl-, α-linolenoyl docosahexaenoyl-, linoleoyl-, and oleoyl-ethanolamines in rabbit cornea, and following treatment with anandamide, the formation of PGF2α-EA, PGE2-EA, PGD2-EA by corneal extracts (all analyzed by LC/ESI-MS/MS). A number of N-acyl phosphatidylethanolamines, precursors of anandamide and other fatty acyl ethanolamines, were also identified in corneal lipid extracts using ESI-MS/MS. These findings suggest that the prostamide and fatty acid ethanolamine pathways are operational in the cornea and may provide valuable insight into corneal physiology and their potential influence on adjacent tissues and the aqueous humor.

The evolving role of the endocannabinoid system in gynaecological cancer

BACKGROUND

The 'endocannabinoid system' (ECS), comprising endogenous ligands (endocannabinoids) and their regulating enzymes, together with the cannabinoid receptors, has attracted a great deal of attention because it affects not only all facets of human reproduction, from gametogenesis through to parturition and beyond, but also targets key mechanisms affecting some hallmarks of cancer. Recent evidence showing that cannabinoid receptors play a very important role in the development of malignancies outside of the reproductive organs suggests a similar role for the ECS in the establishment or continued development of gynaecological malignancy.

METHODS

Primary papers and review articles, and primary sources within these papers, up to December 2014, on the evolving role of the ECS in cancer, with a special focus on gynaecological cancers, were obtained by Medline and PubMed searches using the search terms: 'cancer', 'cannabinoid', 'endocannabinoid', 'gynaecology' and 'malignancy'. Non-English manuscripts were excluded.

RESULTS

More than 2100 sources were obtained from which only 112 were specifically important to the topic. Analysis of those articles supports a role of the ECS in gynaecological cancers but leaves many gaps in our knowledge that need to be filled. How some of the relevant receptors are activated and cause changes in cell phenotypes that progress to malignancy remains undiscovered and an area for future research. Increasing evidence suggests that malignant transformation within the female genital tract could be accompanied by deregulation of components of the ECS, acting through rather complex cannabinoid receptor-dependent and receptor-independent mechanisms.

CONCLUSIONS

The paucity of studies in this area suggests that research using animal models is needed to evaluate endocannabinoid signalling in cancer networks. Future randomized clinical studies should reveal whether endocannabinoids or their derivatives prove to be useful therapeutic targets for gynaecological and other cancers.