Biology subjects

Cheon, S.

Publications and source records attributed to Cheon, S..

3 recordsLinked to original sources

bioRxiv2023

Epigenetic vulnerabilities of leukemia harboring inactivating EZH2 mutations

Epigenetic regulators such as the polycomb repressive complex 2 (PRC2) play a critical role in both normal development and carcinogenesis. Mutations and functional dysregulation of PRC2 complex components such as EZH2 are implicated in various forms of cancer and associated with poor prognosis. This study investigated the epigenetic vulnerabilities of acute myeloid leukemia (AML) and myelodysplastic/myeloproliferative disorders (MDS/MPN) by performing a chemical probe screen in patient cells. Paradoxically, we observed increased sensitivity to EZH2 and EED inhibitors in AML and MDS/MPN patient cells harboring EZH2 mutations. Expression analysis indicated that EZH2 inhibition elicited upregulation of pathways responsible for cell death and growth arrest, specifically in patient cells with mutant EZH2. The identified EZH2 mutations had drastically reduced catalytic activity, resulting in lower cellular H3K27me3 levels and were associated with decreased EZH2 and PRC2 component EED protein levels. Overall, this study provides an important understanding of the role of EZH2 dysregulation in blood cancers and may indicate disease etiology for these poor prognosis AML and MDS/MPN cases.

cancer biology↗

bioRxiv2022

Peroxiredoxin 5 regulates osteogenic differentiation via interaction with hnRNPK during bone regeneration

Peroxiredoxin 5 (Prdx5) is involved in pathophysiological regulation via the stress-induced cellular response. However, the function of Prdx5 in the bone remains largely unknown. Here, we show that Prdx5 is involved in osteoclast and osteoblast differentiation, resulting in osteoporotic phenotypes in Prdx5 knockout (Prdx5Ko) mice. Through immunoprecipitation and liquid chromatography combined with tandem mass spectrometry analysis, heterogeneous nuclear ribonucleoprotein K (hnRNPK) was identified as a potential binding partner of Prdx5 during osteoblast differentiation in vitro. We found that Prdx5 acts as a negative regulator of hnRNPK-mediated osteocalcin (Ocn) expression. In addition, transcriptomic analysis revealed that in vitro differentiated osteoclasts from the bone marrow-derived macrophages of Prdx5Ko mice showed enhanced expression of several osteoclast-related genes. These findings indicate that Prdx5 might contribute to the maintenance of bone homeostasis by regulating osteoblast differentiation. This study proposes a new function of Prdx5 in bone remodeling that may be used in developing therapeutic strategies for bone diseases.

cell biology↗

bioRxiv2020

COVID-19 patients upregulate toll-like receptor 4-mediated inflammatory signaling that mimics bacterial sepsis

Observational studies of the ongoing coronavirus disease 2019 (COVID-19) outbreak suggest that a cytokine storm is involved in the pathogenesis of severe illness. However, the molecular mechanisms underlying the altered pathological inflammation in COVID-19 are largely unknown. We report here that toll-like receptor (TLR) 4-mediated inflammatory signaling molecules are upregulated in peripheral blood mononuclear cells (PBMCs) from COVID-19 patients, compared with healthy controls. Among the most highly increased inflammatory mediators in severe/critically ill patients, S100A9, an alarmin and TLR4 ligand, was found as a noteworthy biomarker, because it inversely correlated with the serum albumin levels. These data support a link between TLR4 signaling and pathological inflammation during COVID-19 and contribute to develop therapeutic approaches through targeting TLR4-mediated inflammation.

immunology↗