JAK2V617F⁺ myeloproliferative neoplasm clones evoke paracrine DNA damage to adjacent normal cells through secretion of lipocalin-2

Genetic instability is strongly involved in cancer development and progression, and elucidating the mechanism could lead to novel the rapeutics for preventing carcinogenesis. Philadelphia-negative myeloproliferativeneoplasms(MPNs) are clonalmyeloid disorders with a high prevalence of JAK2V617F mutation, and transformation to acute myeloid leukemia through accumulation of additional mutations is a major complication in MPNs. Here, we showed that JAK2V617F1 cells conferred paracrine DNA damage to neighboring normal cells as well as to themselves through increased reactive oxygen species (ROS). We screened candidate factors responsible for the effect and found that lipocalin-2 (Lcn2) is overexpressed in JAK2V617F1 cells and that short hairpin RNA-mediated knockdown of Lcn2 significantly alleviated the paracrine DNA damage. Normal hematopoietic cells showed elevated ROS levels through increased intracellular iron levels when treated with lipocalin-2, which led to p53 pathway activation, increased apoptosis, and decreased cellular proliferation.In contrast, JAK2V617F1 cells did not suffer from lipocalin-2-induced growth suppression resulting from attenuated p53 pathway activation, which conferred a relative growth advantage to JAK2V617F1 clones. In summary, we demonstrated that JAK2V617F-harboring cells cause paracrine DNA damage accumulation through secretionoflipocalin-2, which gives proliferative advantage to themselves andan increased risk for leukemic transformation to both JAK2V617F⁺ and JAK2V617F-clones.