A Review of the Therapeutic Antitumor Potential of Cannabinoids.

 

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“The aim of this review is to discuss cannabinoids from a preclinical and clinical oncological perspective and provide the audience with a concise, retrospective overview of the most significant findings concerning the potential use of cannabinoids in cancer treatment.

RESULTS:

Cannabis sativa is a plant rich in more than 100 types of cannabinoids. Besides exogenous plant cannabinoids, mammalian endocannabinoids and synthetic cannabinoid analogues have been identified. Cannabinoid receptors type 1 (CB1) and type 2 (CB2) have been isolated and characterized from mammalian cells. Through cannabinoid receptor and non-receptor signaling pathways, cannabinoids show specific cytotoxicity against tumor cells, while protecting healthy tissue from apoptosis. The dual antiproliferative and proapoptotic effects of cannabinoids and associated signaling pathways have been investigated on a large panel of cancer cell lines. Cannabinoids also display potent anticancer activity against tumor xenografts, including tumors that express high resistance to standard chemotherapeutics. Few studies have investigated the possible synergistic effects of cannabinoids with standard oncology therapies, and are based on the preclinically confirmed concept of “cannabinoid sensitizers.” Also, clinical trials aimed to confirm the antineoplastic activity of cannabinoids have only been evaluated on a small number of subjects, with no consensus conclusions regarding their effectiveness.

CONCLUSIONS:

A large number of cannabinoid compounds have been discovered, developed, and used to study the effects of cannabinoids on cancers in model systems. However, few clinical trials have been conducted on the use of cannabinoids in the treatment of cancers in humans. Further studies require extensive monitoring of the effects of cannabinoids alone or in combination with standard anticancer strategies. With such knowledge, cannabinoids could become a therapy of choice in contemporary oncology.”

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The Role of Cannabinoids in the Treatment of Cancer in Pediatric Patients.

“Cannabis has been used in folk medicine to alleviate pain, depression, amenorrhea, inflammation and numerous other medical conditions. In cancer patients specifically, cannabinoids are well known to exert palliative effects; their best-established use is the inhibition of chemotherapy-induced nausea and vomiting, but they are applied also to alleviate pain, stimulate appetite, and attenuate wasting. More recently, cannabinoids have gained special attention for their role in cancer cell proliferation and death.

Anti-cancer efficacy of cannabinoids:

The ability of cannabinoids to reduce tumor growth was reported for the first time by Munson et al. in 1975. They showed by in vitro and in vivo experiments that several phytocannabinoids, including THC, decreased Lewis lung adenocarcinoma proliferation in a dose-dependent manner. Nevertheless, it was not until the 2000s that the interest in these compounds as anti-cancer agents was renewed, predominantly due to the work of Guzman in gliomas, and the demonstration of cannabinoids’ anti-cancer effects on various types of tumors. The anti-tumorigenic effect of the endo- and phytocannabinoids was demonstrated in several in vitro and in vivo models of a wide variety of adult tumors including glioma, prostate, breast, leukemia, lymphoma, pancreas, melanoma, thyroid, colorectal and hepatocellular carcinoma tumors.

Given our positive results, we suggest that non-THC cannabinoids such as CBD might provide a basis for the development of novel therapeutic strategies without the typical psychotropic effects of THC that limit its use in pediatric patients.

Overall, the cannabinoids, and specifically the non-psychoactive CBD, may show future promise in the treatment of cancer”

https://www.ima.org.il/FilesUpload/IMAJ/0/228/114216.pdf

https://www.ima.org.il/imaj/ViewArticle.aspx?aId=4044

https://www.ncbi.nlm.nih.gov/pubmed/28457057

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Anti-inflammatory effects of the cannabidiol derivative dimethylheptyl-cannabidiol – studies in BV-2 microglia and encephalitogenic T cells

“Preparations derived from Cannabis sativa (marijuana and hashish) have become widespread since ancient times, both as therapeutic agents and in recreational smoking.

Among the more than 60 phytocannabinoids identified in Cannabis extracts, the two most abundant are Δ9-tetrahydrocannabinol (THC), the major psychotropic constituent, and cannabidiol (CBD), the major non-psychoactive component.

Cannabinoids were shown to exert a wide range of therapeutic effects, and many of the cannabinoids, especially CBD, were shown to possess potent anti-inflammatory and immunomodulatory activities. In addition, it was shown that several cannabinoids have pro-apoptotic, neuroprotective, and antitumor properties

Dimethylheptyl-cannabidiol (DMH-CBD), a non-psychoactive, synthetic derivative of the phytocannabinoid cannabidiol (CBD), has been reported to be anti-inflammatory in RAW macrophages. Here, we evaluated the effects of DMH-CBD at the transcriptional level in BV-2 microglial cells as well as on the proliferation of encephalitogenic T cells.

The results show that DMH-CBD has similar anti-inflammatory properties to those of CBD. DMH-CBD downregulates the expression of inflammatory cytokines and protects the microglial cells by inducing an adaptive cellular response against inflammatory stimuli and oxidative injury. In addition, DMH-CBD decreases the proliferation of pathogenic activated TMOG cells.

Several CBD derivatives were also shown to have anti-inflammatory and anti-proliferative properties.

The results show that DMH-CBD induces similar anti-inflammatory, anti-proliferative, and stress response effects to those previously observed for CBD.”

https://www.degruyter.com/view/j/jbcpp.2016.27.issue-3/jbcpp-2015-0071/jbcpp-2015-0071.xml

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Dietary ω-3 Polyunsaturated Fatty Acids Inhibit Tumor Growth in Transgenic ApcMin/+ Mice, Correlating with CB1 Receptor Up-Regulation.

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“Mediterranean diet components, such as olive oil and ω-3 polyunsaturated fatty acids (ω-3 PUFAs), can arrest cell growth and promote cell apoptosis.

Recently, olive oil has been demonstrated to modulate type-1 cannabinoid (CB1) receptor gene expression in both human colon cancer cells and rat colon. The aim of this study was to investigate a possible link between olive oil and ω-3 PUFAs effects and CB1 receptor expression in both intestinal and adipose tissue of ApcMin/+ mice.

To confirm the role for the CB1 receptor as a negative modulator of cell proliferation in human colon cancer, CB1 receptor gene expression was also detected in tumor tissue and in surrounding normal mucosa of patients with colorectal cancer (CRC).

Dietary ω-3 PUFAs significantly inhibited intestinal polyp growth in mice, correlating with CB1 receptor gene and protein expression induction. CB1 receptor gene up-regulation was also detected in adipose tissue, suggesting a close communication between cancer cells and the surrounding environment. Tissue CB1 receptor induction was associated with a concurrent inactivation of the Wnt/β-catenin pathway.

Moreover, there was a significant reduction in CB1 receptor gene expression levels in cancer tissue compared to normal surrounding mucosa of patients with CRC, confirming that in cancer the “protective” action of the CB1 receptor is lost.”

https://www.ncbi.nlm.nih.gov/pubmed/28245562

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Cannabinoid derivatives exert a potent anti-myeloma activity both in vitro and in vivo.

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“Although hematopoietic and immune system show high levels of the cannabinoid receptor CB2, the potential effect of cannabinoids on hematologic malignancies has been poorly determined.

Here we have investigated their anti-tumor effect in multiple myeloma (MM).

We demonstrate that cannabinoids induce a selective apoptosis in MM cell lines and in primary plasma cells of MM patients, while sparing normal cells from healthy donors, including hematopoietic stem cells.

Remarkably, blockage of the CB2 receptor also inhibited cannabinoid-induced apoptosis.

Cannabinoid derivative WIN-55 enhanced the anti-myeloma activity of dexamethasone and melphalan overcoming resistance to melphalan in vitro. Finally, administration of cannabinoid WIN-55 to plasmacytoma-bearing mice significantly suppressed tumor growth in vivo.

Together, our data suggest that cannabinoids may be considered as potential therapeutic agents in the treatment of MM.”

https://www.ncbi.nlm.nih.gov/pubmed/27778331

http://www.thctotalhealthcare.com/category/multiple-myeloma/

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Cannabinoids synergize with carfilzomib, reducing multiple myeloma cells viability and migration.

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“Several studies showed a potential anti-tumor role for cannabinoids, by modulating cell signaling pathways involved in cancer cell proliferation, chemo-resistance and migration.

Cannabidiol (CBD) was previously noted in multiple myeloma (MM), both alone and in synergy with the proteasome inhibitor bortezomib, to induce cell death.

In other type of human cancers, the combination of CBD with Δ9-tetrahydrocannabinol (THC) was found to act synergistically with other chemotherapeutic drugs suggesting their use in combination therapy.

In the current study, we evaluated the effects of THC alone and in combination with CBD in MM cell lines.

We found that CBD and THC, mainly in combination, were able to reduce cell viability by inducing autophagic-dependent necrosis.

Moreover, we showed that the CBD-THC combination was able to reduce MM cells migration by down-regulating expression of the chemokine receptor CXCR4 and of the CD147 plasma membrane glycoprotein.

Furthermore, since the immuno-proteasome is considered a new target in MM and also since carfilzomib (CFZ) is a new promising immuno-proteasome inhibitor that creates irreversible adducts with the β5i subunit of immuno-proteasome, we evaluated the effect of CBD and THC in regulating the expression of the β5i subunit and their effect in combination with CFZ.

Herein, we also found that the CBD and THC combination is able to reduce expression of the β5i subunit as well as to act in synergy with CFZ to increase MM cell death and inhibits cell migration.

In summary, these results proved that this combination exerts strong anti-myeloma activities.”

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Cannabinoid receptor activation inhibits cell cycle progression by modulating 14-3-3β.

“Cannabinoids display various pharmacological activities, including tumor regression, anti-inflammatory and neuroprotective effects.

To investigate the molecular mechanisms underlying the pharmacological effects of cannabinoids, we used a yeast two-hybrid system to screen a mouse brain cDNA library for proteins interacting with type 1 cannabinoid receptor (CB1R). Using the intracellular loop 3 of CB1R as bait, we identified 14-3-3β as an interacting partner of CB1R and confirmed their interaction using affinity-binding assays. 14-3-3β has been reported to induce a cell cycle delay at the G2/M phase.

We tested the effects of cannabinoids on cell cycle progression in HeLa cells synchronized using a double-thymidine block-and-release protocol and found an increase in the population of G2/M phase cells. We further found that CB1R activation augmented the interaction of 14-3-3β with Wee1 and Cdc25B, and promoted phosphorylation of Cdc2 at Tyr-15.

These results suggest that cannabinoids induce cell cycle delay at the G2/M phase by activating 14-3-3β.”

http://www.ncbi.nlm.nih.gov/pubmed/25002257

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Endocannabinoid system as a regulator of tumor cell malignancy – biological pathways and clinical significance

“The endocannabinoid system (ECS) comprises cannabinoid receptors (CBs), endogenous cannabinoids, and enzymes responsible for their synthesis, transport, and degradation of (endo)cannabinoids.

To date, two CBs, CB1 and CB2, have been characterized; however, orphan G-protein-coupled receptor GPR55 has been suggested to be the third putative CB.

Several different types of cancer present abnormal expression of CBs, as well as other components of ECS, and this has been shown to correlate with the clinical outcome.

Although most effects of (endo)cannabinoids are mediated through stimulation of classical CBs, they also interact with several molecules, either prosurvival or proapoptotic molecules.

It should be noted that the mode of action of exogenous cannabinoids differs significantly from that of endocannabinoid and results from the studies on their activity both in vivo and in vitro could not be easily compared.

This review highlights the main signaling pathways involved in the antitumor activity of cannabinoids and the influence of their activation on cancer cell biology.

We also discuss changes in the expression pattern of the ECS in various cancer types that have an impact on disease progression and patient survival.

A growing amount of experimental data imply possible exploitation of cannabinoids in cancer therapy.”

https://www.dovepress.com/endocannabinoid-system-as-a-regulator-of-tumor-cell-malignancy-ndash-b-peer-reviewed-article-OTT

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Inhibition of autophagy and enhancement of endoplasmic reticulum stress increase sensitivity of osteosarcoma Saos-2 cells to cannabinoid receptor agonist WIN55,212-2.

“WIN55,212-2, a cannabinoid receptor agonist, can activate cannabinoid receptors, which has proven anti-tumour effects in several tumour types. Studies showed that WIN can inhibit tumour cell proliferation and induce apoptosis in diverse cancers.

However, the role and mechanism of WIN in osteosarcoma are still unclear. In this study, we examined the effect of WIN55,212-2 on osteosarcoma cell line Saos-2 in terms of cell viability and apoptosis. Meanwhile, we further explored the role of endoplasmic reticulum stress and autophagy in apoptosis induced by WIN55,212-2.

Our results showed that the cell proliferation of Saos-2 was inhibited by WIN55,212-2 in a dose-dependent and time-dependent manner. WIN55,212-2-induced Saos-2 apoptosis through mitochondrial apoptosis pathway. Meanwhile, WIN55,212-2 can induce endoplasmic reticulum stress and autophagy in Saos-2 cells. Inhibition of autophagy and enhancement of endoplasmic reticulum stress increased apoptosis induced by WIN55,212-2 in Saos-2 cells.

These findings indicated that WIN55,212-2 in combination with autophagic inhibitor or endoplasmic reticulum stress activator may shed new light on osteosarcoma treatment.”

http://www.ncbi.nlm.nih.gov/pubmed/27309350

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Inhibition of human tumour prostate PC-3 cell growth by cannabinoids R(+)-Methanandamide and JWH-015: Involvement of CB2

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“We have previously shown that cannabinoids induce growth inhibition and apoptosis in prostate cancer PC-3 cells, which express high levels of cannabinoid receptor types 1 and 2 (CB1 and CB2). In this study, we investigated the role of CB2 receptor in the anti-proliferative action of cannabinoids and the signal transduction triggered by receptor ligation.

This study defines the involvement of CB2-mediated signalling in the in vivo and in vitro growth inhibition of prostate cancer cells and suggests that CB2 agonists have potential therapeutic interest and deserve to be explored in the management of prostate cancer.

Cannabinoids, the active components of Cannabis sativa and their derivatives, exert a wide spectrum of modulatory actions and pharmacological activities in the brain as well as in the periphery, and therefore, the therapeutic potential of cannabinoids has gained much attention during the past few years. One of the most exciting areas of current research in the therapeutic potential of cannabinoids is cancer.

Recent evidence suggests that cannabinoids are powerful regulators of cell growth and differentiation. They have been shown to exert anti-tumoural effects by decreasing viability, proliferation, adhesion and migration on various cancer cells, thereby suggesting the potential use of cannabinoids in the treatment of gliomas, prostate and breast cancers and malignancies of immune origin.

Overall, our data show a role for the cannabinoid receptor CB2 in the anti-tumour effect of cannabinoids on prostate cells in vitroand in vivo. There is considerable interest in the application of selective CB2 receptor agonists, which are devoid of typical marijuana-like psychoactive properties of CB1 agonists, for future cannabinoid-based anticancer therapies. Therefore, our findings point to the potential application of cannabinoid receptor type 2 ligands as anti-tumour agents in prostate cancer.”

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