- Title
- Investigation into the anti-acute myeloid leukaemia and complementary health benefits of medicinal cannabis
- Creator
- Afrin, Farjana
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2024
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Acute myeloid leukaemia (AML) is the most common acute leukaemia in adults and presents a significant therapeutic challenge, with limited advancements in treatment options despite the detailed understanding of the molecular landscapes of the disease. In this study, I explored the therapeutic potential of the cannabinoid compounds cannabidiol (CBD), Δ9-tetrahydrocannabinol (Δ9-THC), low-Δ9-THC cannabis crude extracts referred to as ‘Hemp’ in treating AML, with a focus on patients harbouring the most common driver mutation FMS-like tyrosine kinase 3 (FLT3). In vitro experiments using a panel of human AML cell lines harbouring recurring mutations in FLT3 (MV4-11, MOLM-13), NRAS (HL-60, THP-1), and KIT (KASUMI-1) showed CBD to exhibit greater anti-AML effects (average IC50 13.7 μM) than Δ9-THC (average IC50 24.4 μM), with Hemp displaying even higher potency (average IC50 4.08 μg/mL, approximately 2.7 μM of CBD). Hemp extracts comprise other cannabinoids including CBD, cannabigerol (CBG), cannabinol (CBN), and cannabichromene (CBC), that may contribute to the increased response of AML cells to this treatment. The investigation extends to show the induction of apoptosis by CBD and Hemp in AML cell lines and ex vivo patient samples, demonstrating higher sensitivity in FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) mutated cells and a significant increase in apoptosis in patient blasts (p < 0.0001). The study further explores synergism through a combination of Hemp and CBD with the standard chemotherapeutic drug cytarabine (Ara-C) showing, synergistic, additive, and even antagonistic results, depending on the cell line used. Importantly, the study assesses the impact of crude Hemp extracts on the self-renewal of normal bone marrow haematopoietic stem/progenitor cells (HSPCs). Results showed that Hemp extracts have non-toxic effects on healthy HSPCs, suggesting a potential therapeutic avenue that does not interfere with the body’s natural self-renewal and differentiation of stem cells, which is crucial for maintaining a healthy immune system. Proteomic and phosphoproteomic analysis of AML cell line MV4-11 treated with CBD, Δ9-THC, a 1:1 ratio of CBD-Δ9-THC, and Hemp help to characterise downstream signalling following exposure. These innovative studies show downregulation of FLT3 and MYC signalling pathways resulting in reduced proliferation and cell growth. Downregulation of FLT3 and MYC signalling by CBD and Hemp was confirmed by Western immunoblotting, demonstrating a significant (p < 0.001) decrease of FLT3 phosphorylation, along with downstream decreased phosphorylation of MYC targets (p < 0.001). Additionally, the CBD and Hemp increased H2AX phosphorylation (γH2AX), and reduced DNA-dependent protein kinase (DNA-PK) phosphorylation (p < 0.05) in FLT3-ITD mutated cell line (MV4-11) to show that CBD and Hemp induced oxidative DNA damage causing apoptosis. As Ingenuity Pathway Analysis (IPA) and Integrative Inferred Kinase Activity (InKA) analysis identified decreased FLT3 signalling, I investigated whether this cannabinoid (CBD) had the potential to act as a partial antagonist of the FLT3 receptor by molecular docking analysis. Importantly, CBD demonstrated comparable binding potential to the widely used type II FLT3 inhibitor sorafenib, suggestive of direct interactions with this oncogene. In vivo studies using AML mouse models further confirmed the potential of CBD and Hemp against acute myeloid leukaemia. A significant reduction in leukaemic burden was seen in both the 100 mg/kg of CBD (p < 0.01) and 150 mg/kg of Hemp (p < 0.05) treatment groups and reduction in leukaemia cells were also evident in the peripheral blood of mice treated with CBD (p = 0.0005) and Hemp (p < 0.0001). CBD-treated mice maintained consistent body weight, suggesting potential therapeutic advantage (p = 0.0016) and survival benefit (29%). Hemp-treated mice showed variations in body weight, but survival benefit was achieved (11.5%, p = 0.1641). In vivo pharmacokinetic (PK) studies showed peak plasma concentration of CBD 2 hours post-administration. The study also assessed spleen size, as commonly AML patients experience splenomegaly, finding that compared to vehicle control both CBD (p < 0.05) and Hemp alleviate splenomegaly without observable toxicity or adverse effects. Overall, this research advocates for clinical trials to explore the potential of CBD and Hemp as innovative treatments for AML, particularly in FLT3-mutant cases unable to receive standard induction chemotherapy which might provide elderly patients with increased quality of life and potentially extra time with their families.
- Subject
- acute myeloid leukaemia; medicinal cannabis; cannabinoid compounds; hemp
- Identifier
- http://hdl.handle.net/1959.13/1510024
- Identifier
- uon:56337
- Rights
- This thesis is currently under embargo and will be available from 17.07.2025. Copyright 2024 Farjana Afrin
- Language
- eng
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