Oncogenic Kras<sup>G12D</sup> causes myeloproliferation via NLRP3 inflammasome activation.

Hamarsheh, Shaima'a; Osswald, Lena; Saller, Benedikt S; Unger, Susanne; De Feo, Donatella; Vinnakota, Janaki Manoja; Konantz, Martina; Uhl, Franziska M et al. · Nat Commun · 2020

basic_science · Level V

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Abstract

Oncogenic Ras mutations occur in various leukemias. It was unclear if, besides the direct transforming effect via constant RAS/MEK/ERK signaling, an inflammation-related effect of KRAS contributes to the disease. Here, we identify a functional link between oncogenic Kras<sup>G12D</sup> and NLRP3 inflammasome activation in murine and human cells. Mice expressing active Kras<sup>G12D</sup> in the hematopoietic system developed myeloproliferation and cytopenia, which is reversed in Kras<sup>G12D</sup> mice lacking NLRP3 in the hematopoietic system. Therapeutic IL-1-receptor blockade or NLRP3-inhibition reduces myeloproliferation and improves hematopoiesis. Mechanistically, Kras<sup>G12D</sup>-RAC1 activation induces reactive oxygen species (ROS) production causing NLRP3 inflammasome-activation. In agreement with our observations in mice, patient-derived myeloid leukemia cells exhibit KRAS/RAC1/ROS/NLRP3/IL-1β axis activity. Our findings indicate that oncogenic KRAS not only act via its canonical oncogenic driver function, but also enhances the activation of the pro-inflammatory RAC1/ROS/NLRP3/IL-1β axis. This paves the way for a therapeutic approach based on immune modulation via NLRP3 blockade in KRAS-mutant myeloid malignancies.

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