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Biomedical subjects

Athanasios G Papavassiliou

Publications and source records attributed to Athanasios G Papavassiliou.

2 recordsLinked to original sources
PubMed2026

Targeting SUV4-20H2-mediated H4K20 methylation restrains growth and migration in pediatric high-grade astrocytomas.

Pediatric astrocytomas are characterized by increased molecular and clinical heterogeneity with epigenetic alterations contributing to aggressiveness and therapy resistance. The repressive histone mark H4K20 trimethylation (H4K20me3) and the methyltransferase SUV4-20H2 (KMT5C) are critical regulators of chromatin integrity and genome stability, with limited investigation in pediatric astrocytomas. KMT5C mRNA levels were evaluated in a publicly available pediatric gliomas database using bioinformatic analysis. Investigation of SUV4-20H2 and H4K20me3 expression was performed in a cohort of 43 pediatric astrocytoma tissues by immunohistochemistry. Their functional role and mechanism of action was investigated in pediatric glioma cell lines by using the substrate-competitive inhibitor of SUV4-20, A-196. Cell viability, apoptosis and migration were assessed using XTT, cleaved PARP, and wound healing assays, respectively. Effects of treatment on H4K20 methylation, DNA damage, mitotic stress [Polo-like kinase (PLK1) expression], and invasion markers (N-cadherin, β-catenin expression) were examined by western immunoblotting. KMT5C mRNA was significantly enriched in pediatric high-grade astrocytomas compared to low-grade tumors. A significant elevation of SUV4-20H2 and H4K20me3 expression was detected in astrocytoma tissues indicating epigenetic dysregulation contributing to malignancy. Treatment with A-196 reduced cell proliferation of pediatric glioma cell lines and induced apoptosis in a dose-dependent manner. It further impaired cell migration, accompanied by reduced N-cadherin and β-catenin expression. Mechanistically, inhibition of SUV4-20 depleted H4K20me3, inducing chromatin destabilization, replication-associated DNA damage and was associated with increased PLK1 expression, consistent with activation of a mitotic stress response. Our findings indicate that SUV4-20H2-mediated H4K20 activity in pediatric high-grade astrocytomas maintains their growth and migratory potential by regulating chromatin integrity and may serve as potential therapeutic target.

H4K20me2/3↗
PubMed2026

LARS promotes hepatocellular carcinoma progression via the PI3K/AKT/mTOR pathway and interaction with RPS5, and serves as a prognostic biomarker.

BACKGROUND: Hepatocellular carcinoma (HCC) caused many cancer deaths around the world. Its progression involves complex mechanisms, creating an urgent need to identify new therapeutic targets. Leucine-tRNA synthetase (LARS) is a key enzyme for protein synthesis, but its specific role and mechanism in HCC are not well understood. PURPOSE: This research aims to investigate the biological function, molecular mechanism, and clinical relevance of the LARS gene in HCC progression, to assess its potential as a treatment target. METHODS: LARS expression was assessed in HCC cell lines (PLC-PRF-5, HCC-LM3) and in mouse subcutaneous tumor models using siRNA and adeno-associated virus (AAV). Techniques including Cell Counting Kit-8(CCK-8), colony formation, EdU, Transwell, wound healing, and flow cytometry were used to measure cell proliferation, migration, invasion, and apoptosis. RNA-seq, proteomics (TMT), western blot, co-immunoprecipitation (Co-IP) with mass spectrometry, molecular docking, and molecular dynamics simulation were employed to study the affected signaling pathway (PI3K/AKT/mTOR) and interacting protein (RPS5). The TCGA (The Cancer Genome Atlas) database and UALCAN platform were used to analyze links between LARS expression and clinicopathological features or prognosis in HCC patients. RESULTS: Reducing LARS expression significantly inhibited the proliferation, colony formation, migration, and invasion of HCC cells, while promoting apoptosis. In mice, LARS knockdown markedly slowed tumor growth. Mechanistic studies showed that reducing LARS expression levels affected the PI3K/AKT/mTOR signaling pathway and led to decreased levels of the key interacting protein RPS5. Overexpressing RPS5 partly reversed the proliferation inhibition caused by LARS depletion. Molecular docking and dynamics simulations suggested that the environmental contaminant triphenyl phosphate (TPP) might bind to the LARS protein. Clinical data analysis revealed that LARS expression is higher in HCC tissues. High LARS expression was significantly associated with shorter overall survival (OS) in patients and correlated positively with various clinical features like tumor stage, grade, and TP53 mutation status. CONCLUSION: LARS helped HCC become worse by affecting the PI3K/AKT/mTOR pathway and working with RPS5. High LARS meant a worse outcome for patients. This suggested LARS could be used to predict disease or as a treatment target in HCC.

Carcinoma, Hepatocellular↗