The 2nd International Annual Congress on Controversies on Cannabis-Based Medicines (Med-Cannabis 2019), Barcelona, Spain, May 23–24, 2019

The 2nd International Annual Congress on Controversies on Cannabis-Based Medicines (Med-Cannabis 2019)

Barcelona, Spain, May 23–24, 2019



Congress Chairs:

Prof. Dr. Med. Winfried Häuser, Klinikum Saarbrücken, Germany
Dr. Silviu Brill, Tel Aviv Medical Center, Israel

Medical Cannabis & Cannabinoids, 2019, 2, 69–83

Published online: May 13, 2019

Doi : 10.1159/000500623

KRAGER : Basel · Freiburg · Paris · London · New York · Chennai · New Delhi ·
Bangkok · Beijing · Shanghai · Tokyo · Kuala Lumpur · Singapore · Sydney

© 2019 The Author(s)
Published by S. Karger AG, Basel


Cannabis and Metals: Soils Need to be Controlled

Yann Barguil , Laura Chiaradia
Biochemistry and Toxicology Laboratory, Gaston Bourret Territorial Hospital Center, New Caledonia

Background: Transition metals are well represented in mining regions, as in New Caledonia (NC) and could form reactive carbonyl species when burned.

Objective: To evaluate the toxicity of cannabis growing on ultramafic soils.

Methods: Metals of 49 NC cannabis flower heads samples from outdoor crops and soils from different NC sites were assayed by ICP-AES. Moreover, 500 mg of 4 NC cannabis samples underwent incomplete combustion for 10 min. Fumes were aspirated, cooled and condensed in a methanol bath. Ni, Co, Cr, Mn and Fe, condensation baths, tars, and methanol control solutions were assayed by ICP-MS.

Results: Heavy metals appear to passively enter cannabis. Depending on soil composition, we obtained four groups of cannabis:
High levels of Al group (maximum level (Lmax) 6780 μg/g of dry plant).
High levels of Ni and Co group (Lmax: 95 and 2 μg/g, respectively).
High levels of Cr, Ni and Co group (Lmax: 400, 620, 40 μg/g, respectively).
High levels of Mn group (Lmax: 14818 μg/g).
In NC cannabis, Fe levels are high when soils are rich in ferronickel (23910 μg/g). In addition, high levels of Pb, Cu and Os were observed (30, 124 and 45 μg/g, respectively). These metal levels are much higher than levels found in commercial tobaccos.

Some NC cannabis samples have a Ni content nearly 500 times higher (620 μg/g) than these tobaccos. The following maximum quantities were trapped in the fumes by “bang” of 500 mg of cannabis: 360 ng of Ni, 2.8 ng of Cr, 0.4 ng Mn, 100.4 ng of Fe.

Conclusion: At high temperature, inhalation of transition metals present in cannabis could reinforce the deleterious effects of tar in smokers. For the purpose of commercialization and/or medicine manufacture, soils should be controlled and alternatives to the burning of cannabis should be encouraged.


Cannabidiol Effects Viability of Breast Cancer Cell Lines that Express CB1 and CB2 Receptors

Fran Krstanović 1,2,3, Patrik Levačič 1,2, Metka Novak 3, Luka Dobovišek 4, Polonca Ferk 5, Tamara Lah Turnšek 3, Simona Borštnar 4, Nataša Debeljak 1

1Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Slovenia; 2BSc & MSc Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Slovenia; 3Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Slovenia; 4Institute of Oncology, Institute of Oncology, Slovenia; 5Institute for Biostatistics and Medical Informatics, Faculty of Medicine, University of Ljubljana, Slovenia

Background: The vast majority of all known breast cancers are estrogen receptor (ER) positive. Current treatment includes tamoxifen, which binds to ER and inhibits estrogen dependent transcription. Apart from that, (endo) cannabinoids have recently been demonstrated to affect progression and induce anti-tumor responses in certain cancer types, including breast cancer. Endocannabinoid receptors (CBs) include G-proteins found in the central nervous system (Type 1 receptor, CB1) and in the immune system (Type 2 receptor, CB2). Recent studies have also shown that tamoxifen metabolites and isomers act as inverse agonists on CBs, and are toxic in an ER-independent mechanism.

Objectives: To evaluate expression of CB1 and CB2 receptors in breast cancer cell lines of different subtypes and with different hormone status (ER+/PR+/HER2–, ER–/PR–/HER2+ and triplenegative). To measure the effect of pure CBD, alone or in combination with tamoxifen and chemotherapy on viability of breast cancer cell lines.

Methods: Breast cancer cell lines (MCF7, MDA-MB-231, MDA-MB-361, T-47D, SK-BR-3) were cultured using standard cell culturing protocol. The expression levels of CB1 and CB2 receptors in breast cancer cell lines were analyzed using immunocytochemistry, comparing two different primary antibodies. We tested one of the commercially most used polyclonal antibodies against CB1 and CB2 receptors (manufactured by Abcam), and were among the first to test the new monoclonal antibody against both CBs (manufactured by Santa Cruz Biotechnology). The effect of pure CBD, tamoxifen and chemotherapy was measured using MTT assay.

Results: CB1 and CB2 receptor expression results differ among the cell lines and the used antibodies and also show the unspecificity of Santa Cruz antibodies. Breast cancer cell lines that express CB1 and CB2 receptors have reduced viability after the treatment with pure CBD, including the aggressive triple negative line.

Conclusion: The results propose CBD as a useful treatment for different breast cancer subtypes.

Cannabinoids Affect Viability of Differentiated Glioblastoma Cells and Stem Cells Derived from Patients with Different CB1 and CB2 Receptor Levels

Bernarda Majc 1, Metka Novak 1, Barbara Žvar Baškovič 1, Barbara Breznik 1, Mateja Burjek 1, Andrej Porčnik 3, Roman Bošnjak 3, Jernej Mlakar 2, Tamara Lah Turnšek 1, Roby Zommer 4

1Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Slovenia; 2Institute of Pathology, Faculty of Medicine, University of Ljubljana, Slovenia;
3Department of Neurosurgery, University Medical Centre Ljubljana, Slovenia, Slovenia; 4MGC Pharmaceuticals, MGC Pharmaceuticals d.o.o., Slovenia

Background: Glioblastoma (GB) is the most aggressive and therapeutically non-responsive primary brain tumour. Survival of patients ranges from 12 to 15 months after the diagnosis, in spite of improved treatments in irradiation and chemotherapy. This is mainly due to inefficient targeting of therapeutically resistant glioblastoma stem cells (GSCs), therefore new adjuvant treatment options against GSCs are urgently needed. Increasing number of preclinical studies have shown that cannabinoids induce the processes leading to anti-tumour responses in some types of cancer, including glioblastoma.

Objectives: To evaluate expression of CB1 and CB2 receptors in a small cohort of GB patients, in patient-derived tumour tissues,- primary cultures of GB cells, GSCs and in established GB cell lines. Secondly, to identify most effective cannabinoids, their ratios and combinations with chemotherapeutic (Temozolomide-TMZ) to alter GB and GSC cell viability/cytotoxicity, apoptosis and proliferation.

Methods: Primary GB and GSC cell lines were established from a set of patient GB tumours. We analysed the expression profile of CB1 and CB2 receptor on GB tissue sections, patient derived glioblastoma cells and GSCs by immunolabelling. The effect of cannabinoids on GB cell viability, apoptosis and proliferation was studied using MTT assay, AnnexinV FC and Ki67 immunostaining.

Results and Conclusions: CB2 receptor was highly expressed in all tumour tissue samples while differentiated GB cells express moderate level of both receptors, in contrast to high levels of CB1 and CB2 in GSCs. Cannabinoids, especially at higher THC concentrations reduce viability of GB cells. The response to cannabinoids was even higher on GSCs. No synergistic effects between cannabinoids and TMZ under our experimental conditions was observed. These conditions did not reduce GB proliferation nor induce apoptosis.

We conclude that targeting GSC with cannabinoids may turn out to be promising adjuvant strategy to reduce glioblastoma growth.


Oxidative Stress Responses and Cholinesterase Activity in Blood and Brain of Wistar Rats Exposed to Δ9-Tetrahydrocannabinol

Anja Mikolić 1, Suzana Žunec 2, Vedran Micek 3, Irena Brčić Karačonji 1, Marijana Neuberg 4, Goran Kozina 4, Ana Lucić Vrdoljak 2

1Analytical Toxicology and Mineral Metabolism Unit, Institute for Medical Research and Occupational Health, Croatia; 2Toxicology Unit, Institute for Medical Research and Occupational Health, Croatia; 3Animal Breeding Unit, Institute for Medical Research and Occupational Health, Croatia; 4University North, University Centre Varaždin, Croatia

Background: Today, we are faced with the increasing use of illegal highly concentrated Δ9-tetrahydrocannabinol (THC) preparations as supportive therapies for various malignancies and neurological disorders. Due to the fact that some, such as cannabis oils and butane hash oil, may contain over 80% of THC, their consumers can become intoxicated or experience various detrimental effects.

Objective: The aim of this study was to assess the toxic effects of THC in male Wistar rats orally exposed to 7 mg/kg b.w. THC, which is comparable to the dose find in illicit preparations.

Methods: The rats were sacrificed 24 h after treatment and plasma and brain samples were collected and stored for biochemical analyses. We determined the extent of oxidative stress as well as changes in activities of plasma and brain cholinesterases (ChE) in THC-treated and control rats.

Results: Acute oral administration of 7 mg/kg b.w. THC did not cause changes in oxidative stress biomarkers in rat plasma, but did cause a significant elevation of TBARS and GSH concentration and a drop in SOD activity was observed in brain tissue. Cholinesterase activities were not affected either in the plasma or in brain tissue.

Conclusion: The present study contributes to existing knowledge with evidence that acute exposure to a high THC dose induced oxidative stress in the brain, but did not affect changes in ChE activity.