Biology subjects

Chien, K.

Publications and source records attributed to Chien, K..

3 recordsLinked to original sources

bioRxiv2026

Aberrant oxidative metabolism selects for TET2-deficient hematopoietic stem and progenitor cells

The mechanism(s) driving selective expansion of mutant hematopoietic stem and progenitor cells (HSPC) in clonal hematopoiesis (CH) are incompletely understood. Here, we address the role of metabolism in selection for HSPC with loss of function mutations in TET2. Loss of Tet2 in murine HSPC triggers overexpression of glycolysis and oxidative phosphorylation genes and increased oxidative metabolism via an enlarged mitochondrial network. However, Tet2-deficient HSPC maintain a normal redox state. Strikingly, compound loss of the rate-limiting pentose phosphate pathway (PPP) enzyme glucose-6-phosphate dehydrogenase (G6PD) triggers increased reactive oxygen species and impairs the fitness of Tet2-deficient HSPC. We find that aberrant oxidative metabolism is also a feature of HSPC in human CH and clonal cytopenia of unknown significance (CCUS). Overall, our data point to aberrant metabolism as a critical and conserved driver of selection in TET2-deficient CH and identify the PPP as a crucial compensatory pathway needed to maintain their selective advantage. Statement of SignificanceThis study identifies oxidative metabolism as a critical driver of selection for TET2-deficient HSPC in clonal hematopoiesis (CH). It also demonstrates that cellular redox state is a vulnerability that impairs their fitness. These insights establish targetable metabolic pathway(s) that could be exploited in the setting of TET2 mutant CH.

cancer biology↗

bioRxiv2023

IL-1B-mediated inflammatory signaling drives ineffective erythropoiesis in early-stage myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a group of incurable hematopoietic stem cell (HSC) neoplasms characterized by peripheral blood cytopenias and a high risk of progression to acute myeloid leukemia. MDS represent the final stage in a continuum of HSCs genetic and functional alterations and are preceded by a premalignant phase, clonal cytopenia of undetermined significance (CCUS). Dissecting the mechanisms of CCUS maintenance may uncover therapeutic targets to delay or prevent malignant transformation. Here, we demonstrate that DNMT3A and TET2 mutations, the most frequent mutations in CCUS, induce aberrant HSCs differentiation towards the myeloid lineage at the expense of erythropoiesis by upregulating IL-1{beta}-mediated inflammatory signaling and that canakinumab rescues red blood cell transfusion dependence in early-stage MDS patients with driver mutations in DNMT3A and TET2. This study illuminates the biological landscape of CCUS and offers an unprecedented opportunity for MDS intervention during its initial phase, when expected survival is prolonged.

cancer biology↗

bioRxiv2023

Hematopoietic Stem Cells Undergo Differentiation State Reprogramming to Overcome Venetoclax Sensitivity in Patients with Myelodysplastic Syndromes

While the molecular mechanisms of acute myeloid leukemia failure to venetoclax-based therapy have been recently clarified, the mechanisms whereby patients with myelodysplastic syndromes (MDS) acquire secondary resistance to venetoclax after an initial response remain to be elucidated. Here, we show for the first time that MDS hematopoietic stem cells (HSCs) can undergo hierarchical differentiation reprogramming toward a granulo-monocytic-biased transcriptional state through the acquisition or expansion of clones with an isolated trisomy 8 cytogenetic aberration and STAG2 or RUNX1 mutations. This hierarchical rewiring changes HSCs survival dependence from BCL-2-mediated anti-apoptotic pathways to TNF-induced pro-survival NF-{kappa}B signaling and overcomes venetoclax-mediated cytotoxic effect. These findings underscore the importance of close molecular monitoring of patients with MDS enrolled in clinical trials of venetoclax to prevent HSC transcriptional reprogramming before the disease becomes resistant to this therapy.

cancer biology↗