Author: delta

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Inhibition of ATM kinase upregulates levels of cell death induced by cannabidiol and γ-irradiation in human glioblastoma cells

Abstract

Despite advances in glioblastoma (GBM) therapy, prognosis of the disease remains poor with a low survival rate. Cannabidiol (CBD) can induce cell death and enhance radiosensitivity of GBM but not normal astrocytes. Inhibition of ATM kinase is an alternative mechanism for radiosensitization of cancer cells. In this study, we increased the cytotoxic effects of the combination of CBD and γ-irradiation in GBM cells through additional inhibition of ATM kinase with KU60019, a small molecule inhibitor of ATM kinase. We observed in GBM cells treated by CBD, γ-irradiation and KU60019 high levels of apoptosis together with strong upregulation of the percentage of G2/M-arrested cells, blockade of cell proliferation and a massive production of pro-inflammatory cytokines. Overall, these changes caused both apoptotic and non-apoptotic inflammation-linked cell death. Furthermore, via JNK-AP1 activation in concert with active NF-κB, CBD upregulated gene and protein expression of DR5/TRAIL-R2 and sensitize GBM cells to TRAIL-induced apoptosis. In contrast, CBD notably decreased in GBM surface levels of PD-L1, a critical immune checkpoint agent for T-lymphocytes. We also used in the present study TS543 human proneural glioma cells that were grown as spheroid culture. TS543 neurospheres exhibited dramatic sensitivity to CBD-mediated killing that was additionally increased in combination with γ-irradiation and KU60019. In conclusion, treatment of human GBM by the triple combination (CBD, γ-irradiation and KU60019) could significantly increase cell death levels in vitro and potentially improve the therapeutic ratio of GBM.

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Can cannabidiol inhibit angiogenesis in colon cancer?

Abstract

Colon cancer is the third most common human malignancy and a main cause of death worldwide. The current study was carried out to investigate the effects of cannabidiol, a cannabinoid, on angiogenesis and cell death in mice with experimental colon cancer induced by injection of CT26 cell line. Fifty male BALB/c mice were assigned randomly to five study groups, including: (1) negative control, (2) cancer control, (3) cancer vehicle control, (3) cancer treatment (1 mg/kg cannabidiol), and (5) cancer treatment (5 mg/kg cannabidiol). Treatment responses were evaluated based on histopathological examination, the expression of vascular endothelial growth factor (VEGF) gene, measurement of interleukins (ILs 6 and 8), oxidative stress parameters (glutathione peroxidase, glutathione reductase, superoxide dismutase serum activities, total antioxidant capacity, and malondialdehyde levels). In the present study, CBD reduced VEGF gene expression, decreased serum levels of IL6, IL8, and malondialdehyde, and increased antioxidant enzyme activity in mice with colon cancer. Moreover, cannabidiol induced apoptosis and reduced cellular pleomorphism. Cannabidiol can be potentially considered as an anti-colon cancer medicine as it exerts an inhibitory effect on angiogenesis, tumor growth, and metastasis through reducing VEGF gene expression, decreasing cytokines, and increasing antioxidant enzyme activities.

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Identifying the Cannabis Compounds that Kill Cancer

In our latest CannMed speaker interview, David Meiri provides some amazing insight into how he and his team are working to understand the specific cannabis compounds that can be used to kill cancer cells. What they have found so far is fascinating.

By testing different cannabis extracts on cancer cells with specific genetic mutations, they can identify which cannabis strains are effective in killing a certain type of cancer cell. From there, they dig deeper into the cell’s mechanisms to figure out how the cannabis compounds block, activate, or change the pathways and determine the minimum compounds needed to produce the effect.

Using this approach Dr. Meiri and his team have found a specific combination of three compounds that kills leukemia cells. Interestingly, if one of those compounds is excluded from the extract, it will not kill the cell. This finding seems to confirm the theory of an entourage effect; however, all 100+ compounds found in the cannabis plant are not needed in this case. What’s even more interesting is that the effective compounds they identified are not the major cannabinoids or terpenes we are all familiar with. In fact, one compound hasn’t even been named in the literature!

Watch the video above to learn more about Dr. Meiri’s work

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Dr David Allen, Cardiac & Trauma Surgeon-Retired / Cannabis Activist and Educator, USA

Topic: When Cannabis is legalized, the war on drugs is won! About: The discovery of the Endocannabinoid Signaling System or ECS is the single most important discovery in human history. The science of the ECS will save more lives than the discovery and application of sterile surgical technique. More humans will be saved by manipulation of the ECS than are currently saved by surgical procedures!

Bio: David Allen began his career as a heart surgeon in the state of Mississippi. During the tenure of his practice he offered his services free of charge to those who did not have medical insurance coverage. He spent most of his career as an advocate for healthy living, and as a medical marijuana proponent. In 2008 David moved to California to become an independent medical cannabis physician. Shorty after opening his practice, the local drug task force targeted and arrested Dr. Allen, who served 14 months in a pre trial prison. He was acquitted by jury nullification in 2011. David has retired from his medical practice under duress. He now spends his time educating others on the endocannabinoid signalling system, medical marijuana, and treating PTSD with Psilocybin.

Nimbin MardiGrass Hemposium
Saturday 5 May 2018
Nimbin Town Hall
NSW Australia
http://nimbinmardigrass.com/

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Regulation of human glioblastoma cell death by combined treatment of cannabidiol, γ-radiation and small molecule inhibitors of cell signaling pathways

Abstract

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. The challenging problem in cancer treatment is to find a way to upregulate radiosensitivity of GBM while protecting neurons and neural stem/progenitor cells in the brain. The goal of the present study was upregulation of the cytotoxic effect of γ-irradiation in GBM by non-psychotropic and non-toxic cannabinoid, cannabidiol (CBD). We emphasized three main aspects of signaling mechanisms induced by CBD treatment (alone or in combination with γ-irradiation) in human GBM that govern cell death: 1) CBD significantly upregulated the active (phosphorylated) JNK1/2 and MAPK p38 levels with the subsequent downregulation of the active phospho-ERK1/2 and phospho-AKT1 levels. MAPK p38 was one of the main drivers of CBD-induced cell death, while death levels after combined treatment of CBD and radiation were dependent on both MAPK p38 and JNK. Both MAPK p38 and JNK regulate the endogenous TRAIL expression. 2) NF-κB p65-P(Ser536) was not the main target of CBD treatment and this transcription factor was found at high levels in CBD-treated GBM cells. Additional suppression of p65-P(Ser536) levels using specific small molecule inhibitors significantly increased CBD-induced apoptosis. 3) CBD treatment substantially upregulated TNF/TNFR1 and TRAIL/TRAIL-R2 signaling by modulation of both ligand and receptor levels followed by apoptosis. Our results demonstrate that radiation-induced death in GBM could be enhanced by CBD-mediated signaling in concert with its marginal effects for neural stem/progenitor cells and astrocytes. It will allow selecting efficient targets for sensitization of GBM and overcoming cancer therapy-induced severe adverse sequelae.

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Inhibition of cervical cancer cell proliferation by cannabidiol

Seventy phytocannabinoids are now known to be synthesized by Cannabis sativa (marijuana) [1]. The major non-psychoactive cannabinoid cannabidiol (CBD) exhibits antiproliferative effects against breast, cervix, colon, glioma, leukemia, ovary, prostate, and thyroid cancer cells [2]. In this study, we investigated the antiproliferative effect of CBD on the ME-180 cervical cancer cell line. The cells were plated at subconfluent density in DMEM-F12 medium containing 10% fetal bovine serum (FBS), and the experiments were carried out in the serum-free medium. CBD inhibited the proliferation of these cells with an IC50 value of approximately 6µM. At 10µM, CBD induced apoptosis of nearly all cells within 24 hours (figure below). However, within few hours of treatment with CBD, the cells also exhibited numerous cytoplasmic vacuoles, reminiscent of paraptosis. Significant reversal of the CBD-induced inhibition of proliferation was observed in the presence of antioxidant α-tocopherol (200µM), Trolox (200µM), peroxisome proliferator-activated receptor-γ antagonist GW9662 (2µM), and ceramidase inhibitor L-cycloserine (100µM). Limited reversal of inhibition of proliferation was also observed in the presence of 2µM of cannabinoid receptor (CB) antagonist AM251 (CB1). Nevertheless, the cytoplasmic vacuoles observed in the presence of CBD persisted in the presence of these compounds, with the exception of α-tocopherol and Trolox. The results of our study suggest that CBD exerts its antiproliferative effect via multiple mechanisms, and it could be a potential treatment for cervical cancer.

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Quantitative Analyses of Synergistic Responses between Cannabidiol and DNA-Damaging Agents on the Proliferation and Viability of Glioblastoma and Neural Progenitor Cells in Culture

Abstract

Evidence suggests that the nonpsychotropic cannabis-derived compound, cannabidiol (CBD), has antineoplastic activity in multiple types of cancers, including glioblastoma multiforme (GBM). DNA-damaging agents remain the main standard of care treatment available for patients diagnosed with GBM. Here we studied the antiproliferative and cell-killing activity of CBD alone and in combination with DNA-damaging agents (temozolomide, carmustine, or cisplatin) in several human GBM cell lines and in mouse primary GBM cells in cultures. This activity was also studied in mouse neural progenitor cells (NPCs) in culture to assess for potential central nervous system toxicity. We found that CBD induced a dose-dependent reduction of both proliferation and viability of all cells with similar potencies, suggesting no preferential activity for cancer cells. Hill plot analysis indicates an allosteric mechanism of action triggered by CBD in all cells. Cotreatment regimens combining CBD and DNA-damaging agents produced synergistic antiproliferating and cell-killing responses over a limited range of concentrations in all human GBM cell lines and mouse GBM cells as well as in mouse NPCs. Remarkably, antagonistic responses occurred at low concentrations in select human GBM cell lines and in mouse GBM cells. Our study suggests limited synergistic activity when combining CBD and DNA-damaging agents in treating GBM cells, along with little to no therapeutic window when considering NPCs.

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