Proapoptotic effect of endocannabinoids in prostate cancer cells

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.

Anti-proliferative, pro-apoptotic and anti-invasive effect of EC/EV system in human osteosarcoma

Osteosarcoma is the most common and aggressive bone tumor in children. The Endocannabinoid/Endovanilloid system has been proposed as anticancer target in tumor of different origins. This system is composed of two receptors (CB1 and CB2), the Transient Potential Vanilloid 1 (TRPV1) channel and their ligands and enzymes. CB1 is expressed mainly in central nervous system while CB2 predominantly on immune and peripheral cells. We investigated the effects of JWH-133 (CB2 agonist) and RTX (TRPV1 agonist) in six human Osteosarcoma cell lines: MG-63, U-2OS, MNNG/HOS, Saos-2, KHOS/NP, Hs888Lu, by Apoptosis and Migration-Assay. We also compared the effects of these compounds on Caspase-3, AKT, MMP-2 and Notch-1 regulation by Q-PCR and Western Blotting.

We observed an anti-proliferative, pro-apoptotic, anti-invasive effect. Our results show that both CB2 stimulation and TRPV1 activation, in different Osteosarcoma cell lines, can act on the same pathways to obtain the same effect, indicating the Endocannabinoid/Endovanilloid system as a new therapeutic target in Osteosarcoma.

Systematic review of the potential role of cannabinoids as antiproliferative agents for urological cancers

INTRODUCTION

The palliative effects of cannabis sativa (marijuana), which include appetite stimulation, attenuation of nausea and emesis, and pain relief, are well known. The active components of cannabis sativa (cannabinoids) and their derivatives have received growing interest due to their diverse pharmacological activities, such as cell growth inhibition and tumour regression. The aim of this review is to look at the current evidence on the antiproliferative effects of cannabinoids in urological malignancies, including renal, prostate, bladder, and testicular cancers.

METHODS

We conducted a systematic review of studies exploring the effect of cannabinoids on tumour activity, including all study types except expert opinions. A formal search was run on Medline database from 1946 to September 2016, along with a hand-search on PubMed for relevant studies.

RESULTS

The search yielded a total of 93 studies from Medline and PubMed, of which 23 studies were included in the final analysis. To date, there are various in vitro studies elucidating the potential mechanism of action of cannabinoids for urological cancers, along with population-based studies specifically for testicular malignancies. To date, no clinical trials have been conducted for urological cancer patients.

CONCLUSIONS

These results demonstrate that the role of endocannabinoids for urological malignancies is an area of active research. Further research is required not only to evaluate the crosstalk between cancer signaling pathways and cannabinoids, but also large randomized clinical studies with urological patients need to be conducted before cannabinoids can be introduced as potential therapeutic options for urological neoplasms.

Synthesis and Evaluation of the Novel Prostamide, 15-Deoxy, Δ12,14-Prostamide J2, as a Selective Antitumor Therapeutic

15-deoxy, Δ^12,14-prostaglandin J₂-ethanolamide, also known as 15-deoxy, Δ^12,14-prostamide J₂ (15d-PMJ₂) is a novel product of the metabolism of arachidonoyl ethanolamide (AEA) by COX-2. 15d-PMJ₂ preferentially induced cell death and apoptosis in tumorigenic A431 keratinocytes and B16F10 melanoma cells compared with nontumorigenic HaCaT keratinocytes and Melan-A melanocytes. Activation of the ER stress execution proteins, PERK and CHOP10, was evaluated to determine whether this process was involved in 15d-PMJ₂ cell death. 15d-PMJ₂ increased the phosphorylation of PERK and expression of CHOP10 in tumorigenic but not nontumorigenic cells. The known ER stress inhibitors, salubrinal and 4-phenylbutaric acid, significantly inhibited 15d-PMJ₂-mediated apoptosis, suggesting ER stress as a primary apoptotic mediator. Furthermore, the reactive double bond present within the cyclopentenone structure of 15d-PMJ₂ was identified as a required moiety for the induction of ER stress apoptosis. The effect of 15d-PMJ₂ on B16F10 melanoma growth was also evaluated by dosing C57BL/6 mice with 0.5 mg/kg 15d-PMJ₂ Tumors of animals treated with 15d-PMJ₂ exhibited significantly reduced growth and mean weights compared with vehicle and untreated animals. TUNEL and IHC analysis of tumor tissues showed significant cell death and ER stress in tumors of 15d-PMJ₂-treated compared with control group animals. Taken together, these findings suggest that the novel prostamide, 15d-PMJ₂, possesses potent antitumor activity in vitro and in vivoMol Cancer Ther; 16(5); 838-49. ©2017 AACR.

Cannabinoid signaling in health and disease

Cannabis sativa has long been used for medicinal purposes. To improve safety and efficacy, compounds from C. sativa were purified or synthesized and named under an umbrella group as cannabinoids. Currently, several cannabinoids may be prescribed in Canada for a variety of indications such as nausea and pain. More recently, an increasing number of reports suggest other salutary effects associated with endogenous cannabinoid signaling including cardioprotection. The therapeutic potential of cannabinoids is therefore extended; however, evidence is limited and mechanisms remain unclear. In addition, the use of cannabinoids clinically has been hindered due to pronounced psychoactive side effects. This review provides an overview on the endocannabinoid system, including known physiological roles, and conditions in which cannabinoid receptor signaling has been implicated.

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.

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.

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

The endocannabinoid system (ECS) is a group of neuromodulatory lipids and their receptors, which are widely distributed in mammalian tissues. ECS regulates various cardiovascular, nervous, and immune system functions inside cells. In recent years, there has been a growing body of evidence for the use of synthetic and natural cannabinoids as potential anticancer agents. For instance, the CB1 and CB2 receptors are assumed to play an important role inside the endocannabinoid system. These receptors are abundantly expressed in the brain and fatty tissue of the human body. Despite recent developments in molecular biology, there is still a lack of knowledge about the distribution of CB1 and CB2 receptors in the human kidney and their role in kidney cancer. To address this gap, we explore and demonstrate the role of the endocannabinoid system in renal cell carcinoma (RCC). In this brief overview, we elucidate the therapeutic aspects of the endocannabinoid system for various cancers and explain how this system can be used for treating kidney cancer. Overall, this review provides new insights into cannabinoids' mechanisms of action in both in vivo and in vitro models, and focuses on recent discoveries in the field.

Phyto-, endo- and synthetic cannabinoids: promising chemotherapeutic agents in the treatment of breast and prostate carcinomas

INTRODUCTION

The term 'cannabinoids' designates a family of compounds with activity upon cannabinoid receptors. Cannabinoids are classified in three groups: phytocannabinoids, endocannabinoids, and the synthetic analogues of both groups. They have become a promising tool in the treatment of cancer disease, not only as palliative agents, but also as antitumor drugs, due to their ability to inhibit the proliferation, adhesion, migration, invasion, and angiogenesis of tumour cells. Two of the cancers where they have shown high anticancer activity are breast and prostate tumours. Despite this potential clinical interest, several studies have also reported that cannabinoids can stimulate the proliferation of cancer cells at very low concentrations. Areas covered: The aim of this review is to evaluate the promising chemotherapeutic utility of phytocannabinoids, endocannabinoids, and synthetic cannabinoids in breast and prostate cancer. Expert opinion: Cannabinoids, in particular the non-psychoactive CBD, may be promising tools in combination therapy for breast and prostate cancer, due to their direct antitumor effects, their ability to improve the efficacy of conventional antitumor drugs and their usefulness as palliative treatment. Nevertheless, deeper studies to fully establish the mechanisms responsible for their antitumour and pro-tumour properties and their formulation in efficient delivery systems remain to be established.

Heparin exerts anti-apoptotic effects on uterine explants by targeting the endocannabinoid system

Miscarriage caused by Gram-negative bacteria infecting the female genital tract is one of the most common complications of human pregnancy. Intraperitoneal administration of LPS to 7-days pregnant mice induces embryo resorption after 24 h. Here, we show that LPS induced apoptosis on uterine explants from 7-days pregnant mice and that CB1 receptor was involved in this effect. On the other hand, heparin has been widely used for the prevention of pregnancy loss in women with frequent miscarriage with or without thrombophilia. Besides its anticoagulant properties, heparin exerts anti-inflammatory, immunomodulatory and anti-apoptotic effects. Here, we sought to investigate whether the administration of heparin prevented LPS-induced apoptosis in uterine explants from 7-days pregnant mice. We found that heparin enhanced cell survival in LPS-treated uterine explants and that this effect was mediated by increasing uterine FAAH activity. Taken together, our results point towards a novel mechanism involved in the protective effects of heparin.

Endocannabinoids as Guardians of Metastasis

Endocannabinoids including anandamide and 2-arachidonoylglycerol are involved in cancer pathophysiology in several ways, including tumor growth and progression, peritumoral inflammation, nausea and cancer pain. Recently we showed that the endocannabinoid profiles are deranged during cancer to an extent that this manifests in alterations of plasma endocannabinoids in cancer patients, which was mimicked by similar changes in rodent models of local and metastatic cancer. The present topical review summarizes the complexity of endocannabinoid signaling in the context of tumor growth and metastasis.