TET2-mediated mRNA demethylation regulates leukemia stem cell homing and self-renewal

TET2 is recurrently mutated in acute myeloid leukemia (AML) and its deficiency promotes leukemogenesis (driven by aggressive oncogenic mutations) and enhances leukemia stem cell (LSC) self-renewal. However, the underlying cellular/molecular mechanisms have yet to be fully understood. Here, we show that Tet2 defi-ciency significantly facilitates leukemogenesis in various AML models (mediated by aggressive or less aggressive mutations) through promoting homing of LSCs into bone marrow (BM) niche to increase their self-renewal/proliferation. TET2 deficiency in AML blast cells increases expression of Tetraspanin 13 (TSPAN13) and thereby activates the CXCR4/CXCL12 signaling, leading to increased homing/migration of LSCs into BM niche. Mechanistically, TET2 deficiency results in the accumulation of methyl-5-cytosine (m5C) modification in TSPAN13 mRNA; YBX1 specifically recognizes the m5C modification and increases the stability and expression of TSPAN13 transcripts. Collectively, our studies reveal the functional impor-tance of TET2 in leukemogenesis, leukemic blast cell migration/homing, and LSC self-renewal as an mRNA m5C demethylase.

Automated summary

TET2 deficiency promotes leukemogenesis by enhancing leukemia stem cell self-renewal and facilitating their migration into the bone marrow niche. TET2 deficiency increases the expression of TSPAN13, which activates the CXCR4/CXCL12 signaling pathway and promotes the homing and migration of leukemia stem cells. This study reveals the functional importance of TET2 as an mRNA m5C demethylase in leukemogenesis, leukemia cell migration/homing, and stem cell self-renewal.