Endocannabinoids and cannabinoid receptors in ischaemia–reperfusion injury and preconditioning

“This review is aimed to discuss the role of endocannabinoids and CB receptors in various forms of I/R injury (myocardial, cerebral, hepatic and circulatory shock) and preconditioning, and to delineate the evidence supporting the therapeutic utility of selective CB2 receptor agonists, which are devoid of psychoactive effects, as a promising new approach to limit I/R-induced tissue damage.

In this review, we will discuss the triggers and sources of endocannabinoid production during various forms of I/R injury (myocardial, cerebral, hepatic and retinal ischaemia, and circulatory shock) and preconditioning, as well as the diverse role of these novel mediators and their receptors in these processes. We will also overview the accumulating evidence obtained through the use of various synthetic CB1/CB2 receptor ligands, with particular focus on the novel role of CB2 receptors, suggesting that the modulation of the endocannabinoid system can be therapeutically exploited in various forms of I/R injury.

Cerebral I/R (stroke)

The first evidence for the neuroprotective effect of CBs came from the stroke research field from studies using synthetic non-psychotropic CB Dexanabinol/HU-211, which exerted its beneficial effects through CB1/CB2-independent mechanisms.

Collectively, it appears that both CB1 agonists and antagonists may afford neuroprotective effects against cerebral I/R…

There is considerable interest in the development of selective CB2 receptor agonists, which are devoid of psychoactive properties of CB1 agonists, for various inflammatory disorders. Further studies should also establish the therapeutic window of protection during the reperfusion phase with the currently available CB2 receptor agonists, and new compounds should also be designed with better in vivo bioavailability, to devise clinically relevant treatment strategies against various forms of I/R. Nevertheless, the recently observed beneficial effects of CB2 receptor agonists in hepatic and other forms of I/R, coupled with the absence of psychoactive properties, and antifibrotic effects of CB2 receptor in the liver suggest that this approach may represent a novel promising strategy against various forms of I/R injury and other inflammatory disorders.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219536/

Increased Severity of Stroke in CB1 Cannabinoid Receptor Knock-Out Mice

“These findings indicate that endogenous cannabinoid signaling pathways protect mice from ischemic stroke by a mechanism that involves CB1 receptors, and suggest that both blood vessels and neurons may be targets of this protective effect.

 Endogenous cannabinoid signaling pathways have been implicated in protection of the brain from hypoxia, ischemia, and trauma…

Cannabinoids, which include the marijuana constituent Δ9-tetrahydrocannabinol and endogenous cannabinoids (endocannabinoids) produced in the brain, exert many of their effects through the G-protein-coupled CB1 receptor.

Cannabinoids reduce neuronal death from a variety of insults, including excitotoxicity, oxidative stress, hypoxia, ischemic stroke and trauma…

Clinical stroke, which usually results from cerebral ischemia, is a common and frequently incapacitating problem for which satisfactory treatment is generally unavailable. Identifying new endogenous systems that mitigate ischemic brain injury through effects on neurons, blood vessels, or both (such as the endocannabinoid signaling pathway) may help to guide the search for improved therapies.”

Full text: http://www.jneurosci.org/content/22/22/9771.long

Endocannabinoids and obesity.

“A safe and effective antiobesity drug is needed to combat the global obesity epidemic. The discovery of cannabinoids from medicinal herbs has revealed the endocannabinoid system (ECS) in animals and humans, which regulates various physiological activities such as feeding, thermogenesis, and body weight (BW).

Although cannabinoid receptors 1 (CB1) antagonists have shown antiobesity efficacies in animal models and in the clinic, they failed to establish as a treatment due to their psychological side effects.

 Recent studies indicate that CB1 in various peripheral tissues may mediate some of the therapeutic effects of CB1 antagonists, such as improved lipid and glucose homeostasis.

 It rationalizes the development of compounds with limited brain penetration, for minimizing the side effects while retaining the therapeutic efficacies. A survey of the literature has revealed some controversies about how the ECS affects obesity. This review summarizes the research progresses and discusses some future perspectives.”

http://www.ncbi.nlm.nih.gov/pubmed/23374723

Marijuana Oil Cured My Skin Cancer

“When his cancer came back for a fifth time, Michael McShane was desperate for treatment outside of traditional medicine.

The last time squamous cell carcinoma left lumpy tumors around his mouth, doctors cut it away and reconstructed his bottom lip by turning out a portion of its inner layer.

“You can only do most facial tricks once,” McShane, 51, said. “I needed another option.”

As a qualifying medical marijuana patient, he tried “Simpson oil” derived from cannabis plants by a Canadian named Rick Simpson. McShane bought some from an Oak Park dispensary that has since closed and puts a few drops every day on his face. Over the course of about 10 weeks, the tumors faded and then seemed to disappear.

His dermatologist, Ali Moiin, M.D., has said McShane isn’t cured but his cancer cells have decreased by about 60 percent.

“You still have some residual ones, but the size has definitely decreased,” Dr. Moiin told a WWJ reporter in late August, adding he thinks the results merit further scientific study.

Moiin didn’t return phone calls for an interview for this story. He isn’t the doctor who signed the physician certification form for McShane, who has another qualifying medical problem.

In all, since the Michigan Medical Marijuana Program started in April 2009, 2,215 of the state’s licensed physicians have certified that a patient suffers from one of the debilitating conditions identified in the act, and that the patient may find therapeutic and palliative relief from the medical use of marijuana. A total of 105,458 patient registry cards have been issued in that time period.

An estimated 55 doctors signed 70 percent of the certification forms, according to one review; most of the others aren’t talking about it publicly.

“I imagine it is a fairly sensitive issue because it is politically charged,” said Colin Ford, director of state and federal government relations for the Michigan State Medical Society.

Physicians are cautious because patient privacy is important, he said.

A forbidden cure?

Privacy isn’t as important to McShane as sharing what he considers his latest triumph over cancer without surgery, radiation, chemotherapy, reconstructive surgery and their side effects.

“The marijuana oil replaced all that and reduced the cancer to almost nothing,” he said. “My forehead and mouth were in bad shape in the spring. All of a sudden one morning it was there — a callous-like growth the size of a half dollar on my forehead. Skin cancer is my regular nemesis.”

McShane is one of a growing number of people extolling the healing properties of Simpson oil for everything from cancer, AIDS, Crohn’s disease, osteoporosis, arthritis, and diabetes to psoriasis, hemorrhoids and warts. They call it a “forbidden cure,” saying the oil that can be used topically or ingested isn’t given enough credit because it would cut into medical and pharmaceutical profits.”

By Catherine Kavanaugh
Daily Tribune Staff Writer

Video: http://www.youtube.com/watch?v=gr8RPjrsYSI

Cannabinoid receptors as novel targets for the treatment of melanoma

“Melanoma causes the greatest number of skin cancer-related deaths worldwide. Here, we evaluated the efficacy of cannabinoid receptor agonists, a new family of potential antitumoral compounds, at skin melanoma. Human melanomas and melanoma cell lines express CB1 and CB2 cannabinoid receptors. Activation of these receptors decreased growth, proliferation, angiogenesis and metastasis, and increased apoptosis, of melanomas in mice. Cannabinoid antimelanoma activity was independent of the immune status of the animal, could be achieved without overt psychoactive effects and was selective for melanoma cells vs. normal melanocytes.

Cannabinoid antiproliferative action on melanoma cells…

 These findings may contribute to the design of new chemotherapeutic strategies for the management of melanoma.

 …the present report, together with the implication of CB2 receptors in the control of processes such as pain initiation, emesis, and inflammation, opens the attractive possibility of finding cannabinoid-based therapeutic strategies devoid of nondesired psychotropic side effects.

Specifically, the antiproliferative effect of cannabinoids reported here may set the basis for a new therapeutic approach for the treatment of malignant melanoma.”

Full text: http://www.fasebj.org/content/20/14/2633.long

Inhibition of skin tumor growth and angiogenesis in vivo by activation of cannabinoid receptors

“Cannabinoids inhibit skin tumor growth in vivo. Here we show that the CB1 and the CB2 receptor are expressed in normal skin and skin tumors of mice and humans. In cell culture experiments pharmacological activation of cannabinoid receptors induced the apoptotic death of tumorigenic epidermal cells, whereas the viability of nontransformed epidermal cells remained unaffected. Local administration of the mixed CB1/CB2 agonist WIN-55,212-2 or the selective CB2 agonist JWH-133 induced a considerable growth inhibition of malignant tumors generated by inoculation of epidermal tumor cells into nude mice. Cannabinoid-treated tumors showed an increased number of apoptotic cells.

 

Cannabinoids, the active components of Cannabis sativa linnaeus (marijuana)…

Marijuana and its derivatives have been used in medicine for many centuries, and currently there is a renaissance in the study of the therapeutic effects of cannabinoids… cannabinoids may be potential antitumoral agents owing to their ability to induce the regression of various types of tumors, including lung adenocarcinoma, glioma, and thyroid epithelioma in animal models.

This background prompted us to explore whether (a) the skin and skin tumors express cannabinoid receptors; (b) cannabinoid receptor activation exerts a growth-inhibiting action on skin tumors in vivo; and (c) inhibition of angiogenesis is implicated in the anti-tumoral effect of cannabinoids.

Our data show that (a) CB1 and CB2 receptors are present in the skin and skin tumors; (b) local cannabinoid receptor activation induces the regression of skin tumors in vivo; and (c) at least two mechanisms may be involved in this action: direct apoptosis of tumor cells and inhibition of tumor angiogenesis.

These results support a new therapeutic approach for the treatment of skin tumors.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC151833/

Cannabidiol bioavailability after nasal and transdermal application: effect of permeation enhancers.

“The nonpsychoactive cannabinoid, cannabidiol (CBD), has great potential for the treatment of chronic and ‘breakthrough’ pain that may occur in certain conditions like cancer. To fulfill this goal, suitable noninvasive drug delivery systems need to be developed for CBD. Chronic pain relief can be best achieved through the transdermal route, whereas ‘breakthrough’ pain can be best alleviated with intranasal (IN) delivery. Combining IN and transdermal delivery for CBD may serve to provide patient needs-driven treatment in the form of a nonaddictive nonopioid therapy.

CONCLUSION:

The results of this study indicated that CBD could be successfully delivered through the IN and transdermal routes.”

http://www.ncbi.nlm.nih.gov/pubmed/20545522

The association of N-palmitoylethanolamine with the FAAH inhibitor URB597 impairs melanoma growth through a supra-additive action.

“The incidence of melanoma is considerably increasing worldwide. Frequent failing of classical treatments led to development of novel therapeutic strategies aiming at managing advanced forms of this skin cancer. Additionally, the implication of the endocannabinoid system in malignancy is actively investigated…

CONCLUSIONS:

This study suggests the interest of targeting the endocannabinoid system in the management of skin cancer and underlines the advantage of associating endocannabinoids with enzymatic hydrolysis inhibitors.

This may contribute to the improvement of long-term palliation or cure of melanoma.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3364151/

The antimitogenic effect of the cannabinoid receptor agonist WIN55212-2 on human melanoma cells is mediated by the membrane lipid raft.

“Here are reported the antiproliferative effects of the cannabinoid agonist WIN upon human melanoma cells expressing mRNA and protein for both CB1 and CB2 receptors.

While WIN exerted antimitogenic effects, selective CB1 or CB2 agonists were unable to reproduce such effects and selective CB1 and CB2 antagonists did not inhibit WIN-induced cell death. Cells treated with WIN, preincubated with the lipid raft disruptor methylcyclodestrin, were rescued from death. WIN induced activation of caspases and phosphorylation of ERK that were attenuated in cultures treated with methylcyclodestrin.

 Membrane lipid raft complex-mediated antimitogenic effect of WIN in melanoma could represents a potential targets for a melanoma treatment.”

http://www.ncbi.nlm.nih.gov/pubmed/21807457

Cannabidiol Inhibits Growth and Induces Programmed Cell Death in Kaposi Sarcoma–Associated Herpesvirus-Infected Endothelium

“Kaposi sarcoma is the most common neoplasm caused by Kaposi sarcoma–associated herpesvirus (KSHV). Current treatments for Kaposi sarcoma can inhibit tumor growth but are not able to eliminate KSHV from the host. When the host’s immune system weakens, KSHV begins to replicate again, and active tumor growth ensues. New therapeutic approaches are needed.

Cannabidiol (CBD), a plant-derived cannabinoid, exhibits promising antitumor effects without inducing psychoactive side effects. CBD is emerging as a novel therapeutic for various disorders, including cancer.

In this study, we investigated the effects of CBD both on the infection of endothelial cells (ECs) by KSHV and on the growth and apoptosis of KSHV-infected ECs, an in vitro model for the transformation of normal endothelium to Kaposi sarcoma….

Cannabidiol (CBD) was first isolated in 1940. It is a major component of the plant Cannabis sativa, which is also the source of Δ9-tetrahydrocannabinol (Δ9-THC). Due to its multiple biological activities, CBD has been identified as a potential clinical agent. Moreover, CBD affects these activities without the psychoactive side effects that typify Δ9-THC. Recent studies have documented the potential antitumorigenic properties of CBD in the treatment of various neoplasms, including breast cancer, lung cancer, bladder cancer, glioblastoma,and leukemia.CBD induces these effects through a variety of mechanisms and signaling pathways

CBD has been evaluated clinically for the treatment of various conditions, including anxiety, psychosis, and pain. In contrast to other members of the cannabinoid family, CBD has a strong safety profile and induces no psychotropic effects.Therefore, it has become an attractive agent in the search for new anticancer therapies.Our current study demonstrated that CBD preferentially enhanced apoptosis and inhibited the proliferation of KSHV-infected endothelial cells. This selective targeting of KSHV-induced neoplasia suggests that CBD may have a desirable therapeutic index when used to treat cancer. Moreover, a recent study demonstrated that CBD can be delivered effectively by nasal and transdermal routes, which may be particularly valuable for the treatment of Kaposi sarcoma oral or skin lesions.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3527984/