“Glioblastoma multiforme (GBM) is the most frequent and aggressive malignant brain tumour, with a poor prognosis despite available surgical and radio-chemotherapy, rising the necessity for searching alternative therapies. Several preclinical studies evaluating the efficacy of cannabinoids in animal models of GBM have been described, but the diversity of experimental conditions and of outcomes hindered definitive conclusions about cannabinoids efficacy.
A search in different databases (Pubmed, Web of Science, Scopus and SciELO) was conducted during June 2019 to systematically identify publications evaluating the effects of cannabinoids in murine xenografts models of GBM. The tumour volume and number of animals were extracted, being a random effects meta-analysis of these results performed to estimate the efficacy of cannabinoids. The impact of different experimental factors and publication bias on the efficacy of cannabinoids was also assessed. Nine publications, which satisfied the inclusion criteria, were identified and subdivided in 22 studies involving 301 animals.
Overall, cannabinoid therapy reduced the fold of increase in tumour volume in animal models of GBM, when compared with untreated controls. The overall weighted standardized difference in means (WSDM) for the effect of cannabinoids was -1.399 (95% CI: -1.900 to -0.898; P-value<0.0001). Furthermore, treatment efficacy was observed for different types of cannabinoids, alone or in combination, and for different treatment durations.
Cannabinoid therapy was still effective after correcting for publication bias. The results indicate that cannabinoids reduce the tumour growth in animal models of GBM, even after accounting for publication bias.”
“The weak but noteworthy presence of (poly)phenols in hemp seeds has been long overshadowed by the essential polyunsaturated fatty acids and digestible proteins, considered responsible for their high nutritional benefits. Instead, lignanamides and their biosynthetic precursors, phenylamides, seem to display interesting and diverse biological activities only partially clarified in the last decades. Herein, negative mode HR-MS/MS techniques were applied to the chemical investigation of a (poly)phenol-rich fraction, obtained from hemp seeds after extraction/fractionation steps. This extract contained phenylpropanoid amides and their random oxidative coupling derivatives, lignanamides, which were the most abundant compounds and showed a high chemical diversity, deeply unraveled through high resolution tandem mass spectrometry (HR-MS/MS) tools.
The effect of different doses of the lignanamides-rich extract (LnHS) on U-87 glioblastoma cell line and non-tumorigenic human fibroblasts was evaluated. Thus, cell proliferation, genomic DNA damage, colony forming and wound repair capabilities were assessed, as well as LnHS outcome on the expression levels of pro-inflammatory cytokines. LnHS significantly inhibited U-87 cancer cell proliferation, but not that of fibroblasts, and was able to reduce U-87 cell migration, inducing further DNA damage. No modification in cytokines’ expression level was found. Data acquired suggested that LnHS acted in U-87 cells by inducing the apoptosis machinery and suppressing the autophagic cell death.”
“Radiotherapy combined with chemotherapy is the major treatment modality for human glioblastoma multiforme (GBM). GBMs eventually relapse after treatment and the average survival of GBM patients is less than two years.
There is some evidence that cannabidiol (CBD) can induce cell death and increases the radiosensitivity of GBM by enhancing apoptosis. Beside initiation of death, CBD has been demonstrated as an inducer of autophagy.
In the present study, we address the question whether CBD simultaneously induces a protective effect in GBM by upregulating autophagy. Addition of chloroquine that suppressed autophagic flux to 2D GBM cultures increased CBD-induced cell death, presenting proof for the protective autophagy.
Blockage of autophagy upregulated radiation-induced cytotoxicity but only modestly affected the levels of cell death in CBD- or CBD/γ-irradiated 3D GBM cultures. Furthermore, CBD enhanced the pro-apoptotic activities of JNK1/2 and MAPK p38 signaling cascades while partially downregulated the pro-survival PI3K-AKT cascade, thereby changing a balance between cell death and survival.
Suppression of JNK activation partially reduced CBD-induced cell death in 3D GBM cultures. In contrast, co-treatment of CBD-targeted cells with inhibitors of PI3K-AKT-NF-κB, IKK-NF-κB or JAK2-STAT3 pathways killed surviving GBM cells in both 2D and 3D cultures, potentially improving the therapeutic ratio of GBM.”
“Killing efficiency of cannabinoids (CBD, THC and their combination CBD+THC) against GBM in vitro and in animal experiments has been elucidated in numerous studies during the last 15 years. Additional investigations also confirmed a cytotoxic role of cannabinoids for several other types of cancer. A number of studies demonstrated the efficiency of combined treatments of cannabinoids together with γ-irradiation in both cell culture and in animal experiments.”
“Cannabinoids are a group of structurally heterogeneous but pharmacologically related compounds, including plant-derived cannabinoids, synthetic substances and endogenous cannabinoids, such as anandamide and 2-arachidonoylglycerol.
Cannabinoids elicit a wide range of central and peripheral effects mostly mediated through cannabinoid receptors. There are two types of specific Gi/o-protein-coupled receptors cloned so far, called CB1 and CB2, although an existence of additional cannabinoid-binding receptors has been suggested. CB1 and CB2 differ in their predicted amino acid sequence, tissue distribution, physiological role and signaling mechanisms.
Significant alterations of a balance in the cannabinoid system between the levels of endogenous ligands and their receptors occur during malignant transformation in various types of cancer, including gliomas.
Cannabinoids exert anti-proliferative action in tumor cells.
Induction of cell death by cannabinoid treatment relies on the generation of a pro-apoptotic sphingolipid ceramide and disruption of signaling pathways crucial for regulation of cellular proliferation, differentiation or apoptosis. Increased ceramide levels lead also to ER-stress and autophagy in drug-treated glioblastoma cells.
Beyond blocking of tumor cells proliferation cannabinoids inhibit invasiveness, angiogenesis and the stem cell-like properties of glioma cells, showing profound activity in the complex tumor microenvironment. Advances in translational research on cannabinoid signaling led to clinical investigations on the use of cannabinoids in treatments of glioblastomas.”
“Glioma-related epilepsy significantly impact on patients’ quality of life, and can often be difficult to treat. Seizures cause significant morbidity for example neurocognitive deterioration, which may result from seizures themselves or due to adverse effects from antiepileptic drugs. Management of tumour with surgery, radiotherapy and chemotherapy may contribute to seizure control, but tumour related epilepsy is often refractory despite adequate treatment with standard anti-epileptic medications. Given the increasing interest in medicinal cannabis (or cannabidiol or CBD) as an anti-epileptic drug, CBD may help with seizure control in glioma patients with treatment-refractory seizures. Here we present a case of a young lady with recurrent glioma who had refractory seizures despite multiple anti-epileptic agents, who had significant benefit with CBD.”
“Grade IV glioblastoma multiforme is a deadly disease, with a median survival of around 14 to 16 months. Maximal resection followed by adjuvant radiochemotherapy has been the mainstay of treatment since many years, although survival is only extended by a few months. In recent years, an increasing number of data from in vitro and in vivo research with cannabinoids, particularly with the non-intoxicating cannabidiol (CBD), point to their potential role as tumour-inhibiting agents. Herein, a total of nine consecutive patients with brain tumours are described as case series; all patients received CBD in a daily dose of 400 mg concomitantly to the standard therapeutic procedure of maximal resection followed by radiochemotherapy. By the time of the submission of this article, all but one patient are still alive with a mean survival time of 22.3 months (range=7-47 months). This is longer than what would have been expected.”
“Cannabinoid receptors have been detected in human gliomas and cannabinoids have been proposed as novel drug candidates in the treatment of brain tumors.
Aim of this study was to test the in vitro antitumor activity of COR167, a novel cannabinoid CB2-selective agonist displaying high binding affinity for human CB2 receptors, on tumor cells isolated from human glioblastoma multiforme and anaplastic astrocytoma.
COR167 was found to significantly reduce the proliferation of both glioblastoma and anaplastic astrocytoma in a dose-dependent manner at lower doses than other known, less specific CB2 agonists. This activity is independent of apoptosis and is associated with significant reduction of TGF-beta 1 and 2 levels in supernatants of glioma cell cultures.
These findings add to the role of cannabinoid CB2 receptor as a possible pharmacological target to counteract glial tumor growth and encourage further work to explore any other pharmacological effect of this novel CB2 agonist useful in the treatment of human gliomas.”
“Phytocannabinoids are unique terpenophenolic compounds predominantly produced in the glandular trichomes of the cannabis plant (Cannabis sativa L.). The delta-9- tetrahydrocannabinol (THC) is the main active constituent responsible for the plant’s psychoactive effect and, together with the non- psychoactive cannabidiol (CBD), the most investigated naturally occurring cannabinoid.
The first report on the antitumor properties of cannabis compounds appeared more than forty years ago, but the potential of targeting the endocannabinoid system in cancer has recently attracted increasing interest. Our study aimed to review the last decade’s findings on the anticancer potential of plant- derived cannabinoids and the possible mechanisms of their activity.
A large body of in vitro data has been accumulated demonstrating that phytocannabinoids affect a wide spectrum of tumor cells, including gliomas, neuroblastomas, hepatocarcinoma as well as skin, prostate, breast, cervical, colon, pancreatic, lung and hematological cancer.
It has been found that they can stop the uncontrolled growth of cancer cells through the cell-cycle arrest, inhibition of cell proliferation and induction of autophagy and apoptosis. They can also block all the steps of tumor progression, including tumor cell migration, adhesion and invasion as well as angiogenesis. The observed effects are mainly mediated by the cannabinoid CB1 and/or CB2 receptors, although some other receptors and mechanisms unrelated to receptor stimulation may also be involved.
The majority of available animal studies confirmed that phytocannabinoids are capable of effectively decreasing cancer growth and metastasis in vivo. THC was found to be effective against experimental glioma, liver, pancreatic, breast and lung cancer while CBD showed activity against glioma and neuroblastoma, melanoma, colon, breast, prostate and lung cancer. Further in vitro and in vivo studies also greatly support their use in combination with traditional chemotherapy or radiotherapy, which results in improved efficiency, attenuated toxicity or reduced drug resistance.
Taken together most of available preclinical results emphasize the extensive therapeutic potential of THC and CBD in various types of cancers. The potential clinical interest of cannabinoids is additionally suggested by their selectivity for tumor cells as well as their good tolerance and the absence of normal tissue toxicity, which are still the major limitations of most conventional drugs. The accumulated preclinical evidence strongly suggests the need for clinical testing of cannabinoids in cancer patients.”
“The Cannabis plant contains over 100 phytocannabinoids and hundreds of other components. The biological effects and interplay of these Cannabis compounds are not fully understood and yet influence the plant’s therapeutic effects.
Here we assessed the antitumor effects of whole Cannabis extracts, which contained significant amounts of differing phytocannabinoids, on different cancer lines from various tumor origins.
Our results show that specific Cannabis extracts impaired the survival and proliferation of cancer cell lines as well as induced apoptosis.
Our findings showed that pure (-)-Δ9–trans-tetrahydrocannabinol (Δ9-THC) did not produce the same effects on these cell lines as the whole Cannabis extracts. Furthermore, Cannabis extracts with similar amounts of Δ9-THC produced significantly different effects on the survival of specific cancer cells.
In addition, we demonstrated that specific Cannabis extracts may selectively and differentially affect cancer cells and differing cancer cell lines from the same organ origin. We also found that cannabimimetic receptors were differentially expressed among various cancer cell lines and suggest that this receptor diversity may contribute to the heterogeneous effects produced by the differing Cannabis extracts on each cell line.
Our overall findings indicate that the effect of a Cannabis extract on a specific cancer cell line relies on the extract’s composition as well as on certain characteristics of the targeted cells.”
“Many previous reports highlight and demonstrate the anti-tumor effects of cannabinoids. In the last decade, accumulating evidence has indicated that phytocannabinoids might have antitumor properties. A number of in vitro and in vivo studies have demonstrated the effects of phytocannabinoids on tumor progression by interrupting several characteristic features of cancer. These studies suggest that specific cannabinoids such as Δ9-THC and CBD induce apoptosis and inhibit proliferation in various cancer cell lines.”
“Cannabis has long been known to limit or prevent nausea and vomiting, lack of appetite, and pain. For this reason, cannabinoids have been successfully used in the treatment of some of the unwanted side effects caused by cancer chemotherapy.
Besides their palliative effects, research from the past two decades has demonstrated their promising potential as antitumor agents in a wide variety of tumors.
Cannabinoids of endogenous, phytogenic, and synthetic nature have been shown to impact the proliferation of cancer through the modulation of different proteins involved in the endocannabinoid system such as the G protein-coupled receptors CB1, CB2, and GRP55, the ionotropic receptor TRPV1, or the fatty acid amide hydrolase (FAAH).
In this article, we aim to structurally classify the antitumor cannabinoid chemotypes described so far according to their targets and types of cancer. In a drug discovery approach, their in silico pharmacokinetic profile has been evaluated in order to identify appropriate drug-like profiles, which should be taken into account for further progress toward the clinic.
This analysis may provide structural insights into the selection of specific cannabinoid scaffolds for the development of antitumor drugs for the treatment of particular types of cancer.” https://www.ncbi.nlm.nih.gov/pubmed/31214034
“The first report on the antitumor activity of phytocannabinoids was published over four decades ago. During these last years, significant research has been focused on the therapeutic potential of cannabinoids to manage palliative effects in cancer patients. Besides such palliative applications, some cannabinoids have shown anticancer properties. Since inflammation is a common risk factor for cancer, and some cannabinoids have shown anti-inflammatory properties, they could play a role in chemoprevention.” https://www.frontiersin.org/articles/10.3389/fphar.2019.00621/full