Tag Archives: autophagy

Stimulation of the midkine/ALK axis renders glioma cells resistant to cannabinoid antitumoral action

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“Δ9-Tetrahydrocannabinol (THC), the major active ingredient of marijuana, and other cannabinoids inhibit tumor growth in animal models of cancer, including glioma, an effect that relies, at least in part, on the stimulation of autophagy-mediated apoptosis in tumor cells. 

…Altogether, our findings identify Mdk as a pivotal factor involved in the resistance of glioma cells to THC pro-autophagic and antitumoral action, and suggest that selective targeting of the Mdk/ALK axis could help to improve the efficacy of antitumoral therapies for gliomas.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3131933/

Stimulation of ALK by the growth factor midkine renders glioma cells resistant to autophagy-mediated cell death

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“Δ9-tetrahydrocannabinol (THC), the main active component of marijuana, promotes cancer cell death via autophagy stimulation.

We find that activation of the tyrosine kinase receptor ALK by its ligand midkine interferes with the signaling mechanism by which THC promotes autophagy-mediated glioma cell death.”

 http://www.ncbi.nlm.nih.gov/pubmed/21593591

Marijuana Chemical May Fight Brain Cancer – CBSNews

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“The active chemical in marijuana promotes the death of brain cancer cells by essentially helping them feed upon themselves, researchers in Spain report.

Guillermo Velasco and colleagues at Complutense University in Spain have found that the active ingredient in marijuana, THC, causes brain cancer cells to undergo a process called autophagy. Autophagy is the breakdown of a cell that occurs when the cell essentially self-digests.

The team discovered that cannabinoids such as THC had anticancer effects in mice with human brain cancer cells and people with brain tumors . When mice with the human brain cancer cells received the THC, the tumor growth shrank.

Two patients enrolled in a clinical trial received THC directly to the brain as an experimental treatment for recurrent glioblastoma multiforme , a highly aggressive brain tumor. Biopsies taken before and after treatment helped track their progress. After receiving the THC, there was evidence of increased autophagy activity.

The findings appear in the April 1 issue of the Journal of Clinical Investigation.

The patients did not have any toxic effects from the treatment. Previous studies of THC for the treatment of cancer have also found the therapy to be well tolerated, according to background information in journal article.

Study authors say their findings could lead to new strategies for preventing tumor growth.”

http://www.cbsnews.com/2100-500368_162-4913095.html

“Cannabinoid action induces autophagy-mediated cell death through stimulation of ER stress in human glioma cells…These findings describe a mechanism by which THC can promote the autophagic death of human and mouse cancer cells and provide evidence that cannabinoid administration may be an effective therapeutic strategy for targeting human cancers.” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2673842/

 

Cannabinoids inhibit energetic metabolism and induce AMPK-dependent autophagy in pancreatic cancer cells.

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“The anti-tumoral effects of cannabinoids have been described in different tumor systems, including pancreatic adenocarcinoma, but their mechanism of action remains unclear.

We used cannabinoids specific for the CB1 (ACPA) and CB2 (GW) receptors and metabolomic analyses to unravel the potential pathways mediating cannabinoid-dependent inhibition of pancreatic cancer cell growth. Panc1 cells treated with cannabinoids show elevated AMPK activation induced by a ROS-dependent increase of AMP/ATP ratio. ROS promote nuclear translocation of GAPDH, which is further amplified by AMPK, thereby attenuating glycolysis. Furthermore, ROS determine the accumulation of NADH, suggestive of a blockage in the respiratory chain, which in turn inhibits the Krebs cycle. Concomitantly, inhibition of Akt/c-Myc pathway leads to decreased activity of both the pyruvate kinase isoform M2 (PKM2), further downregulating glycolysis, and glutamine uptake.

Altogether, these alterations of pancreatic cancer cell metabolism mediated by cannabinoids result in a strong induction of autophagy and in the inhibition of cell growth.”

http://www.ncbi.nlm.nih.gov/pubmed/23764845

Cannabinoid action induces autophagy-mediated cell death through stimulation of ER stress in human glioma cells

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“Autophagy can promote cell survival or cell death, but the molecular basis underlying its dual role in cancer remains obscure. Here we demonstrate that Δ9-tetrahydrocannabinol (THC), the main active component of marijuana, induces human glioma cell death through stimulation of autophagy…We also showed that autophagy is upstream of apoptosis in cannabinoid-induced human and mouse cancer cell death and that activation of this pathway was necessary for the antitumor action of cannabinoids in vivo.”

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“These findings describe a mechanism by which THC can promote the autophagic death of human and mouse cancer cells and provide evidence that cannabinoid administration may be an effective therapeutic strategy for targeting human cancers.

Δ9-Tetrahydrocannabinol (THC), the main active component of marijuana, exerts a wide variety of biological effects by mimicking endogenous substances — the endocannabinoids — that bind to and activate specific cannabinoid receptors. One of the most exciting areas of research in the cannabinoid field is the study of the potential application of cannabinoids as antitumoral agents.

Cannabinoid administration has been found to curb the growth of several types of tumor xenografts in rats and mice…

 Considering that no signs of toxicity were observed in the clinical trial patients or in tumor-bearing animals treated intracranially, peritumorally, or intraperitoneally with THC, and that no overt toxic effects have been reported in other clinical trials of cannabinoid use in cancer patients for various applications (e.g., inhibition of nausea, vomiting, and pain) and using different routes of administration (e.g., oral, oro-mucosal) our findings support that safe, therapeutically efficacious doses of THC may be reached in cancer patients.”

 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2673842/

Gemcitabine/cannabinoid combination triggers autophagy in pancreatic cancer cells through a ROS-mediated mechanism

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“Pancreatic adenocarcinoma is one of the most aggressive and devastating human malignancies with a death-to-incidence ratio of 0.99. Although it represents only 2–3% of all cancers, pancreatic adenocarcinoma is the fourth cause of death by tumors…

In recent years, there has been increasing interest in cannabinoids as therapeutic drugs for their antineoplastic, anticachectic, and analgesic potential. Growth inhibitory activities of cannabinoids have been demonstrated for various malignancies, including brain, breast, prostate, colorectal, skin and, recently, pancreatic cancer…

In the present study, we have demonstrated that the combination between the standard chemotherapy agent GEM and cannabinoids synergistically inhibited pancreatic adenocarcinoma cell growth by a ROS-dependent autophagic cell death.

These findings support a key role of the ROS-dependent activation of an autophagic program in the synergistic growth inhibition induced by GEM/cannabinoid combination in human pancreatic cancer cells.

GEM and cannabinoids strongly inhibited growth of human pancreatic adenocarcinoma cells in vivo.”

Read more: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3122066/

Marijuana Chemical May Fight Brain Cancer – WebMD

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“Active Component In Marijuana Targets Aggressive Brain Cancer Cells, Study Says
 
The active chemical in marijuana promotes the death of brain cancer cells by essentially helping them feed upon themselves, researchers in Spain report.Guillermo Velasco and colleagues at Complutense University in Spain have found that the active ingredient in marijuana, THC, causes brain cancer cells to undergo a process called autophagy. Autophagy is the breakdown of a cell that occurs when the cell essentially self-digests.The team discovered that cannabinoids such as THC had anticancer effects in mice with human brain cancer cells and people with brain tumors. When mice with the human brain cancer cells received the THC, the tumor growth shrank.Two patients enrolled in a clinical trial received THC directly to the brain as an experimental treatment for recurrent glioblastoma multiforme, a highly aggressive brain tumor.  Biopsies taken before and after treatment helped track their progress.  After receiving the THC, there was evidence of increased autophagy activity.

The findings appear in the April 1 issue of the Journal of Clinical Investigation.

The patients did not have any toxic effects from the treatment. Previous studies of THC for the treatment of cancer have also found the therapy to be well tolerated, according to background information in journal article.

Study authors say their findings could lead to new strategies for preventing tumor growth.”

http://www.webmd.com/cancer/brain-cancer/news/20090401/marijuana-chemical-may-fight-brain-cancer

“Cannabinoid action induces autophagy-mediated cell death through stimulation of ER stress in human glioma cells”: http://www.jci.org/articles/view/37948

Cannabinoid-associated cell death mechanisms in tumor models

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“In recent years, cannabinoids (the active components of Cannabis sativa) and their derivatives have received considerable interest due to findings that they can affect the viability and invasiveness of a variety of different cancer cells. Moreover, in addition to their inhibitory effects on tumor growth and migration, angiogenesis and metastasis, the ability of these compounds to induce different pathways of cell death has been highlighted. Here, we review the most recent results generating interest in the field of death mechanisms induced by cannabinoids in cancer cells. In particular, we analyze the pathways triggered by cannabinoids to induce apoptosis or autophagy and investigate the interplay between the two processes. Overall, the results reported here suggest that the exploration of molecular mechanisms induced by cannabinoids in cancer cells can contribute to the development of safe and effective treatments in cancer therapy.”

http://www.ncbi.nlm.nih.gov/pubmed/22614735

Cannabidiol Induces Programmed Cell Death in Breast Cancer Cells by Coordinating the Cross-talk between Apoptosis and Autophagy

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“Cannabidiol (CBD), a major nonpsychoactive constituent of cannabis, is considered an antineoplastic agent on the basis of its in vitro and in vivo activity against tumor cells. However, the exact molecular mechanism through which CBD mediates this activity is yet to be elucidated. Here, we have shown CBD-induced cell death of breast cancer cells, independent of cannabinoid and vallinoid receptor activation. Electron microscopy revealed morphologies consistent with the coexistence of autophagy and apoptosis. Western blot analysis confirmed these findings. We showed that CBD induces endoplasmic reticulum stress and, subsequently, inhibits AKT and mTOR signaling as shown by decreased levels of phosphorylated mTOR and 4EBP1, and cyclin D1. Analyzing further the cross-talk between the autophagic and apoptotic signaling pathways, we found that beclin1 plays a central role in the induction of CBD-mediated apoptosis in MDA-MB-231 breast cancer cells. Although CBD enhances the interaction between beclin1 and Vps34, it inhibits the association between beclin1 and Bcl-2. In addition, we showed that CBD reduces mitochondrial membrane potential, triggers the translocation of BID to the mitochondria, the release of cytochrome c to the cytosol, and, ultimately, the activation of the intrinsic apoptotic pathway in breast cancer cells. CBD increased the generation of reactive oxygen species (ROS), and ROS inhibition blocked the induction of apoptosis and autophagy. Our study revealed an intricate interplay between apoptosis and autophagy in CBD-treated breast cancer cells and highlighted the value of continued investigation into the potential use of CBD as an antineoplastic agent.”

http://mct.aacrjournals.org/content/10/7/1161.long