BackgroundIt has been previously demonstrated in several cancer models, that Dronabinol (THC) may have anti-tumor activity – however, controversial data exists for acute leukemia. We have anecdotal evidence that THC may have contributed to disease control in a patient with acute undifferentiated leukemia.MethodsTo test this hypothesis, we evaluated the antileukemic efficacy of THC in several leukemia cell lines and native leukemia blasts cultured ex vivo. Expression analysis for the CB1/2 receptors was performed by Western immunoblotting and flow cytometry. CB-receptor antagonists as well as a CRISPR double nickase knockdown approach were used to evaluate for receptor specificity of the observed proapoptotic effects.ResultsMeaningful antiproliferative as well as proapoptotic effects were demonstrated in a subset of cases – with a preference of leukemia cells from the lymphatic lineage or acute myeloid leukemia cells expressing lymphatic markers. Induction of apoptosis was mediated via CB1 as well as CB2, and expression of CB receptors was a prerequisite for therapy response in our models. Importantly, we demonstrate that antileukemic concentrations are achievable in vivo.ConclusionOur study provides rigorous data to support clinical evaluation of THC as a low-toxic therapy option in a well defined subset of acute leukemia patients.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-015-2029-8) contains supplementary material, which is available to authorized users.
Some cannabinol derivatives are said to possess antitumor efficacy. We have evidence that the CB1/2 cannabinoid receptor agonist Delta9-Tetrahydrocannabinol (THC), the major psychoactive component of marijuana, may have contributed to disease control in a patient with acute myeloid leukemia. We speculated that THC may induce apoptosis in native leukemic blasts and thus treated various leukemia cell lines and ex vivo blasts derived from patients with either acute lymphoblastic or myeloid leukemia in dilution series with THC. The antiproliferative effect was measured using an XTT-based assay. Induction of apoptosis was assessed by annexinV-based immunofluorescence analysis. The CB1 antagonist LY320135 or JTE-907, a selective CB2 inverse ligand agonist, were used to confirm involvement of CB1 (mainly expressed in brain tissue) or CB2 (expression in hematologic/lymphoid cells). THC was obtained with permission of the Bundesopiumstelle, Germany. Indeed, we demonstrate potent antiproliferative and proapoptotic efficacy of Delta9-THC in a dose dependent manner in leukemia cell lines of lymphoid and myeloid origin. Pretreatment with LY320135, but not with JTE-907, resulted in a dramatic abrogation of the antileukemic effect seen with THC monotherapy, arguing that THC-induced apoptosis is mediated via the cannabinoid receptor CB1. Besides a proapoptotic effect, THC was able to abrogate cellular differentiation blockage as observed in a change of morphology. Of note, THC was able to induce apoptosis in a subset of leukemia samples derived from patients with acute myeloid (mainly undifferentited AML) or lymphoblastic leukemia. Due to the patient cohort responsive to THC therapy, we speculated that epigenetic modifications might be associated with MLL (mixed lineage leukemia) methyltransferase function. In a global DNA methylation gene array, we could demonstrate that THC leads to modulation of methylation status of histone deacetylases, oncogenes and tumorsuppressors, some reported to be regulated by MLL. Ongoing work is focussing on validation whether THC treatment can be linked to MLL activity using an siRNA approach. In conclusion, while not being able to directly correlate the disease course of the above described patient to marijuana abuse, our in vitro results nevertheless demonstrate that THC mediates antileukemic activity in blasts of some patients ex vivo including that of our patient. Clinical evaluation of cannabinol receptor agonists as low-toxic agents could thus be considered in selected cases of patients with acute leukemia and this approach should further be followed. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4658. doi:1538-7445.AM2012-4658
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.