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

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“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.”

https://www.ncbi.nlm.nih.gov/pubmed/28425013

ENDOCANNABINOID SYSTEM: A multi-facet therapeutic target.

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“Cannabis sativa is also popularly known as marijuana. It is being cultivated and used by man for recreational and medicinal purposes from many centuries.

Study of cannabinoids was at bay for very long time and its therapeutic value could not be adequately harnessed due to its legal status as proscribed drug in most of the countries.

The research of drugs acting on endocannabinoid system has seen many ups and down in recent past. Presently, it is known that endocannabinoids has role in pathology of many disorders and they also serve “protective role” in many medical conditions.

Several diseases like emesis, pain, inflammation, multiple sclerosis, anorexia, epilepsy, glaucoma, schizophrenia, cardiovascular disorders, cancer, obesity, metabolic syndrome related diseases, Parkinson’s disease, Huntington’s disease, Alzheimer’s disease and Tourette’s syndrome could possibly be treated by drugs modulating endocannabinoid system.

Presently, cannabinoid receptor agonists like nabilone and dronabinol are used for reducing the chemotherapy induced vomiting. Sativex (cannabidiol and THC combination) is approved in the UK, Spain and New Zealand to treat spasticity due to multiple sclerosis. In US it is under investigation for cancer pain, another drug Epidiolex (cannabidiol) is also under investigation in US for childhood seizures. Rimonabant, CB1 receptor antagonist appeared as a promising anti-obesity drug during clinical trials but it also exhibited remarkable psychiatric side effect profile. Due to which the US Food and Drug Administration did not approve Rimonabant in US. It sale was also suspended across the EU in 2008.

Recent discontinuation of clinical trial related to FAAH inhibitor due to occurrence of serious adverse events in the participating subjects could be discouraging for the research fraternity. Despite of some mishaps in clinical trials related to drugs acting on endocannabinoid system, still lot of research is being carried out to explore and establish the therapeutic targets for both cannabinoid receptor agonists and antagonists.

One challenge is to develop drugs that target only cannabinoid receptors in a particular tissue and another is to invent drugs that acts selectively on cannabinoid receptors located outside the blood brain barrier. Besides this, development of the suitable dosage forms with maximum efficacy and minimum adverse effects is also warranted.

Another angle to be introspected for therapeutic abilities of this group of drugs is non-CB1 and non-CB2 receptor targets for cannabinoids.

In order to successfully exploit the therapeutic potential of endocannabinoid system, it is imperative to further characterize the endocannabinoid system in terms of identification of the exact cellular location of cannabinoid receptors and their role as “protective” and “disease inducing substance”, time-dependent changes in the expression of cannabinoid receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27086601

Cannabinoid pharmacology in cancer research: A new hope for cancer patients?

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“Cannabinoids have been used for many centuries to ease pain and in the past decade, the endocannabinoid system has been implicated in a number of pathophysiological conditions, such as mood and anxiety disorders, movement disorders such as Parkinson’s and Huntington’s disease, neuropathic pain, multiple sclerosis, spinal cord injury, atherosclerosis, myocardial infarction, stroke, hypertension, glaucoma, obesity, and osteoporosis.

Several studies have demonstrated that cannabinoids also have anti-cancer activity and as cannabinoids are usually well tolerated and do not produce the typical toxic effects of conventional chemotherapies, there is considerable merit in the development of cannabinoids as potential anticancer therapies.

Whilst the presence of psychoactive effects of cannabinoids could prevent any progress in this field, recent studies have shown the value of the non-psychoactive components of cannabinoids in activating apoptotic pathways, inducing anti-proliferative and anti-angiogenic effects.

The aforementioned effects are suggested to be through pathways such as ERK, Akt, mitogen-activated protein kinase (MAPK) pathways, phosphoinositide 3-kinase (PI3K) pathways and hypoxia inducible factor 1 (HIF1), all of which are important contributors to the hallmarks of cancer.

Many important questions still remain unanswered or are poorly addressed thus necessitating further research at basic pre-clinical and clinical levels. In this review, we address these issues with a view to identifying the key challenges that future research needs to address.”

http://www.ncbi.nlm.nih.gov/pubmed/26852955

http://www.thctotalhealthcare.com/category/cancer/

Ligands for cannabinoid receptors, promising anticancer agents.

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“Cannabinoid compounds are unique to cannabis and provide some interesting biological properties.

These compounds along with endocannabinoids, a group of neuromodulator compounds in the body especially in brain, express their effects by activation of G-protein-coupled cannabinoid receptors, CB1 and CB2.

There are several physiological properties attributed to the endocannabinoids including pain relief, enhancement of appetite, blood pressure lowering during shock, embryonic development, and blocking of working memory.

On the other hand, activation of endocannabinoid system may be suppresses evolution and progression of several types of cancer.

According to the results of recent studies, CB receptors are over-expressed in cancer cell lines and application of multiple cannabinoid or cannabis-derived compounds reduce tumor size through decrease of cell proliferation or induction of cell cycle arrest and apoptosis along with desirable effect on decrease of tumor-evoked pain.

Therefore, modulation of endocannabinoid system by inhibition of fatty acid amide hydrolase (FAAH), the enzyme, which metabolized endocannabinoids, or application of multiple cannabinoid or cannabis-derived compounds, may be appropriate for the treatment of several cancer subtypes. This review focuses on how cannabinoid affect different types of cancers.”

http://www.ncbi.nlm.nih.gov/pubmed/26764235

http://www.thctotalhealthcare.com/category/cancer/

Anandamide exerts its antiproliferative actions on cholangiocarcinoma by activation of the GPR55 receptor

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“We have previously shown that AEA exerts growth-suppressing effects on cholangiocarcinoma by inducing apoptosis.

At the time, we assumed that AEA was acting via a receptor-independent mechanism.

However, given the recent discovery and characterization of GPR55 as a novel AEA receptor, our data need to be reassessed to determine if GPR55 activation can decrease cholangiocarcinoma cell proliferation.

Thus, our aims are to determine if these AEA-mediated effects on cholangiocarcinoma cell growth can be attributed to the activation of GPR55.

This data represent the first evidence that GPR55 activation by anandamide can lead to the recruitment and activation of the Fas death receptor complex and that targeting GPR55 activation may be a viable option for the development of therapeutic strategies to treat cholangiocarcinoma.

In conclusion, we have clearly demonstrated a role for GPR55 in the antiproliferative effects of AEA in vivo andin vitro

Cholangiocarcinoma has a very poor prognosis and survival rate; therefore we propose that the development of novel therapeutic strategies that target GPR55 may prove beneficial for the treatment of this devastating disease.

Consistent with our observation that AEA has antiproliferative and pro-apoptotic properties, cannabinoids of various origins (endogenous, plant-derived or synthetic analogues) have been shown to suppress cancer cell growth in vitro as well as in vivo.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3126905/

 

The endocannabinoid anandamide inhibits cholangiocarcinoma growth via activation of the noncanonical Wnt signaling pathway.

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“Cholangiocarcinomas are cancers that have poor prognosis and limited treatment options.

Marijuana and its derivatives have been used in medicine for many centuries.

…cannabinoids might be effective antitumoral agents because of their ability to inhibit the growth of various types of cancer cell lines in culture and in laboratory animals.

Indeed, we have recently demonstrated that the endocannabinoid anandamide (AEA) has antiproliferative effects on cholangiocarcinoma cell lines in vitro via a cannabinoid receptor-independent pathway involving the stabilization of lipid raft-membrane structures and the recruitment of death-receptor complexes into the lipid rafts.

Modulation of the endocannabinoid system may be important in cholangiocarcinoma treatment.

The antiproliferative actions of the noncanonical Wnt signaling pathway warrants further investigation to dissect the mechanism by which this may occur.

We propose that the development of novel therapeutic strategies aimed at modulating the endocannabinoid system, or mimicking the mode of action of AEA, would prove beneficial for the treatment of this devastating disease.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2604798/

 

Opposing actions of endocannabinoids on cholangiocarcinoma growth is via the differential activation of Notch signaling

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“Cholangiocarcinomas are devastating cancers of intrahepatic and extrahepatic origin that are increasing in both their worldwide incidence and mortality rates.

Conventional chemotherapy and radiation therapy are not effective in prolonging long-term survival; therefore it is important to understand the cellular mechanisms of cholangiocarcinoma cell growth with a view to develop novel chemopreventive strategies.

We have recently demonstrated that the endocannabinoids anandamide (AEA) and 2-arachidonyl glycerol (2-AG) exert opposing effects on cholangiocarcinoma cell growth in vitro via cannabinoid receptor-independent mechanisms.

AEA increased presenilin 1 expression and recruitment into the γ-secretase complex whereas 2-AG increased expression and recruitment of presenilin 2.

The development of novel therapeutic strategies aimed at modulating the endocannabinoid system, or mimicking the mode of action of AEA on Notch signaling pathways would prove beneficial for cholangiocarcinoma management.

We propose that the development of novel therapeutic strategies aimed at modulating the endocannabinoid system, or mimicking the mode of action of AEA on Notch signaling pathways would prove beneficial for the treatment of this devastating disease.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2872061/

Opposing actions of endocannabinoids on cholangiocarcinoma growth: recruitment of Fas and Fas ligand to lipid rafts.

The Journal of Biological Chemistry

“Cholangiocarcinomas are devastating cancers of biliary origin with limited treatment options…

Marijuana and its derivatives have been used in medicine for many centuries, and presently there is an emerging renaissance in the study of the therapeutic effects of cannabinoids…

In addition, cannabinoids might be effective antitumoral agents because of their ability to inhibit the growth of various types of cancer cell lines in culture and in laboratory animals.

Modulation of the endocannabinoid system is being targeted to develop possible therapeutic strategies for a number of cancers; therefore, we evaluated the effects of the two major endocannabinoids, anandamide and 2-arachidonylglycerol, on numerous cholangiocarcinoma cell lines…

These findings suggest that modulation of the endocannabinoid system may be a target for the development of possible therapeutic strategies for the treatment of this devastating cancer.

Consistent with our observation that AEA has antiproliferative and proapoptotic properties, cannabinoids of various origins (endogenous, plant-derived, or synthetic analogues) have been shown to suppress cancer cell growth in vitro as well as in vivo.

In conclusion, we have clearly demonstrated opposing actions of the endocannabinoids AEA and 2-AG on cholangiocarcinoma cell proliferation and have shown that these actions are via a cannabinoid receptor-independent but lipid raft-mediated pathway. Furthermore we have shown that the antiproliferative/proapoptotic actions of AEA are mediated via an accumulation of ceramide and the recruitment of the Fas death receptor into the lipid rafts. Cholangiocarcinoma has a very poor prognosis and survival rate; therefore we propose that the development of novel therapeutic strategies aimed at modulating the endocannabinoid system or mimicking the mode of action of AEA would prove beneficial for the treatment of this devastating disease.”

http://www.jbc.org/content/282/17/13098.long

The dual effects of delta(9)-tetrahydrocannabinol on cholangiocarcinoma cells: anti-invasion activity at low concentration and apoptosis induction at high concentration.

“Currently, only gemcitabine plus platinum demonstrates the considerable activity for cholangiocarcinoma.

The anticancer effect of Delta (9)-tetrahydrocannabinol (THC), the principal active component of cannabinoids has been demonstrated in various kinds of cancers.

We therefore evaluate the antitumor effects of THC on cholangiocarcinoma cells.

Both cholangiocarcinoma cell lines and surgical specimens from cholangiocarcinoma patients expressed cannabinoid receptors.

THC inhibited cell proliferation, migration and invasion, and induced cell apoptosis.

THC also decreased actin polymerization and reduced tumor cell survival in anoikis assay. pMEK1/2 and pAkt demonstrated the lower extent than untreated cells.

Consequently, THC is potentially used to retard cholangiocarcinoma cell growth and metastasis.” http://www.ncbi.nlm.nih.gov/pubmed/19916793 

“Cholangiocarcinoma is an epithelial cell malignancy arising from varying locations within the biliary tree showing markers of cholangiocyte differentiation. The most contemporary classification based on anatomical location includes intrahepatic, perihilar, and distal cholangiocarcinoma… Understanding of cholangiocarcinoma biology, the oncogenic landscape of this disease, and its complex interaction with the tumour microenvironment could lead to optimum therapies with improvement in patient survival… Hopefully, personalised or precision medicine is in the near future for the treatment of cholangiocarcinoma” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4069226/

 “Cholangiocarcinomas (bile duct cancers) are a heterogeneous group of malignancies arising from the epithelial cells of the intrahepatic, perihilar and extrahepatic bile ducts.”   http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3731530/

“Cholangiocarcinoma (CC) is the second most common primary hepatic malignancy after hepatocellular cancer. CC accounts for approximately 10%-25% of all hepatobiliary malignancies. CC is a rare malignancy in Western countries, but more common in Asia. There are several established risk factors for CC, including parasitic infections, primary sclerosing cholangitis, biliary-duct cysts, hepatolithiasis, and toxins. Other less-established potential risk factors include inflammatory bowel disease, hepatitis C virus, hepatitis B virus, cirrhosis, diabetes, obesity, alcohol drinking, tobacco smoking, and host genetic polymorphisms.” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3125451/

“Cholangiocarcinoma is a highly malignant cancer of the biliary tract with a poor prognosis, which often arises from conditions causing long-term inflammation, injury, and reparative biliary epithelial cell proliferation. Several conditions are known to be major risk factors for cancer in the biliary tract or gallbladder, including primary sclerosing cholangitis, liver fluke infection, pancreaticobiliary maljunction, and chemical exposure in proof-printing workers.”  http://www.ncbi.nlm.nih.gov/pubmed/24895231

http://www.thctotalhealthcare.com/category/cholangiocarcinoma/

Endocannabinoid system in cancer cachexia.

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“More than 60% of advanced cancer patients suffer from anorexia and cachexia.

This review focuses on the possible mechanisms by which the endocannabinoid system antagonizes cachexia-anorexia processes in cancer patients and how it can be tapped for therapeutic applications.

Cannabinoids stimulate appetite and food intake…

Cannabinoid type 1 receptor activation stimulates appetite and promotes lipogenesis and energy storage.

Further study of cancer-cachexia pathophysiology and the role of endocannabinoids will help us to develop cannabinoids without psychotropic properties, which will help cancer patients suffering from cachexia and improve outcomes of clinical antitumor therapy.”

http://www.ncbi.nlm.nih.gov/pubmed/17563462