Abstract 3806: Cigarette smoke extract permits survival of TET2-/- and JAK2V617F hematopoietic cells

Inactivating somatic mutations in the ten-eleven translocation 2 (TET2) gene is commonly found in clonal hematopoiesis (CH) and contributes to the pathogenesis of myeloid malignancies such as myeloproliferative neoplasms (MPN), myelodysplastic syndrome and acute myeloid leukemia. Incidentally, smoking behavior is associated with CH and we hypothesize that TET2 mutant hematopoietic cells are resistant to the deleterious effects of smoke exposure. Cigarette smoke extract (CSE) was prepared from mainstream cigarette smoke using a standard protocol and volume/volume percentage (v/v %) dilutions used for in vitro exposures. Lineage negative bone marrow cells isolated from TET2 wildtype (TET2+/+) and TET2 knockout (TET-/-) mice were exposed to CSE and cultured in methylcellulose containing semi-solid medium to assess myeloid colony formation. Cells were also grown in liquid culture under long-term culture conditions to demonstrate the effect of CSE on cell proliferation. Peripheral blood mononuclear cells from JAK2V617F positive MPN patients were treated with CSE for colony forming assays. TET2+/+ bone marrow cells showed decreased myeloid colony formation in the presence of CSE while TET2-/- cells were not significantly affected by CSE. Similarly in liquid cultures, TET2-/- lineage negative cells expanded significantly compared to their wildtype counterparts indicating resistance to the growth suppressive effects of CSE. The JAK2V617F mutation is the most common somatic mutation found in MPN patients and we observed that the suppressive effect of CSE on myeloid colony formation was more pronounced in normal subjects than JAK2V617F positive MPN subjects. This suggests that CH associated somatic mutations such as in TET2 promote resistance of bone marrow progenitors to environmental stressors like cigarette smoke, possibly via anti-apoptotic mechanisms. Future studies include studying the effects of inhalation exposure of combustible and electronic cigarette smoke on TET2-/- and JAK2V617F hematopoiesis in competitive bone marrow transplanted mice. Citation Format: Gajalakshmi Ramanathan, Brianna Craver, Rebecca J. Arechavala, David Herman, Michael T. Kleinman, Angela G. Fleischman. Cigarette smoke extract permits survival of TET2-/- and JAK2V617F hematopoietic cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3806.