Forsøksdyr: Anti-inflammatory properties of the bone marrow niche in NRAS-G12D+ leukaemia

Godkjenningsdato 30.06.2020

Godkjenningsperiode 30.06.2020-30.06.2022

This is an application for an extension of the FOTS8252. We will use a number of animals Close to that approved previously; 160. Due to several Challenges including the current pandemic and the working conditions of my Group split in two locations, we need to start, repeat and finish some of our experiments that have been stopped.

We aim to test the contribution of the anti-inflammatory Properties of the bone marrow microenvironment to acute myeloid leukemia (AML). Results will lead to advances in AML knowledge and patient treatment improvement. IL -1 receptor antagonist (IL-1ra) knock-out (KO) and control mice will be used as recipients of mutant Nras G12D and control cells (n=80 mice in total), and changes in disease will be monitored. Recipient mice need to be myeloablated previous to transplantation, through irradiation. Total Whole body irradiation is used in the Field of blood stem cell function and cancer (for more information: It allows to kill proliferating blood cells without significant damage of resting tissues. Depletion of cells together With factors released allows guidance of transplanted cells and forces their proliferation. This is the only way to study blood stem cell function in vivo. Mice might not feel well for the first 7-14 days and may lose up to 25% of their body weight, which after transplant, will be mostly regained by Day 14-21 post-irradiation. All mice will be transplanted after irradiation.

Besides, our previous observations show an increase of IL-1 signaling through IL-1R after IL-1ra deletion using in IL-1ra KO mice (analyzed in vitro under A015). Activation of IL-1R in hematopoietic stem cells (HCS) drives transcription of nuclear factor- kappa B NF-kB; important for HSC homeostasis (Nagai et al., 2006; Esplin et al.,2011; Schuettpelz et al., 2014; Herman et al., 2016; Pietras et al., 2016). Conversely, aberrant expression of NF-kB takes place in leukemia (Zhou et al., 2015) and other cancers and, targeting NF-kB pathway is used as treatment against different cancers (Braud et al., 2009; Karin et al., 2004). Bortezomib, is a proteasome inhibitor that, ultimately, inhibits NF-kB activity (Hideshima et al., 2009; Xue et al., 2011; Fang et al., 2012; Zhou et al., 2015). Using this therapeutic approach, bortezomib, we intend to rescue IL-1ra KO mice phenotype which show a mild myeloproliferative disease with a differentiation of HSC biased to the myeloid compartment (analyzed in vitro under A015). IL-1ra KO mice will be i.p. injected once per week for a maximum of 4 months.This procedure does not cause any stress or discomfort to the mice. A total of 80 mice will be used for this Experiment.

Total numbers in Tromsø will be 100 and in Oslo 60.

The results will provide a novel platform for more efficient therapies against AML, one of the most aggressive and frequent blood disorders that affects adults and children. It is not the goal of this study to analyze terminal stages. Mice will be used in the most efficient way and numbers will be kept to minimum. The irradiation will be performed in two half doses to reduce the adverse effects.