Lysine 2-hydroxyisobutyrylation proteomics reveals protein modification alteration in the actin cytoskeleton pathway of oral squamous cell carcinoma.

As the most commonplace malignant carcinoma in the oral cavity, oral squamous cell carcinoma (OSCC) is highly invasive and prone to recurrence. The nosogenesis of OSCC are affected by epigenetics. Recently, a newly-found post-translational modification of lysine, 2-hydroxyisobutylation (Khib), has been proved to play a critical role in biological regulation. However, no research has evaluated the mechanism of Khib in oral cancer. Here, we performed liquid chromatography-mass spectrometry-based quantitative proteomics combined with bioinformatics analysis to reveal and evaluate Khib protein alterations in OSCC. Numerous proteins in OSCC undergo up-regulated modification of Khib. We quantified and identified 967 proteins with differential expression levels, and 617 2-hydroxyisobutylated proteins with 938 Khib sites. Among them, 125 proteins both differentially expressed and accompanied by obvious Khib modification were further identified and analyzed through KEGG-based and ingenuity pathway analysis (IPA). These proteins are enriched in the actin cytoskeleton regulatory pathway, and IPA predicted that they alter the state of actin aggregation and stability, hence impacting and regulating the actin cytoskeleton in OSCC. This is the first 2-hydroxyisobutylated modification proteomics performed for OSCC. Khib protein is significantly concentrated in the actin cytoskeleton regulatory pathway, indicating that this pathway may mediate the tumorigenesis or exacerbation of OSCC. SIGNIFICANCE: This is the first study that revealed the alterations of Khib protein in oral squamous cell carcinoma through LC-MS/MS-based modified proteomic. Our data showed that the protein in the actin cytoskeleton regulatory pathway was underwent significant Khib modification and abundance changes. We applied predictive function in IPA software to analyze and clarify that the aggregation of actin and the regulation of actin stability that mediated by the actin cytoskeleton regulatory pathway may be the potential mechanism of the occurrence and development of oral squamous cell carcinoma. Our research broadens the understanding of the pathogenesis of oral squamous cell carcinoma and provides new insights for future research.

Bioinformatic identification of key genes and analysis of prognostic values in clear cell renal cell carcinoma.

The present study aimed to identify new key genes as potential biomarkers for the diagnosis, prognosis or targeted therapy of clear cell renal cell carcinoma (ccRCC). Three expression profiles (GSE36895, GSE46699 and GSE71963) were collected from Gene Expression Omnibus. GEO2R was used to identify differentially expressed genes (DEGs) in ccRCC tissues and normal samples. The Database for Annotation, Visualization and Integrated Discovery was utilized for functional and pathway enrichment analysis. STRING v10.5 and Molecular Complex Detection were used for protein-protein interaction (PPI) network construction and module analysis, respectively. Regulation network analyses were performed with the WebGestal tool. UALCAN web-portal was used for expression validation and survival analysis of hub genes in ccRCC patients from The Cancer Genome Atlas (TCGA). A total of 65 up- and 164 downregulated genes were identified as DEGs. DEGs were enriched with functional terms and pathways compactly related to ccRCC pathogenesis. Seventeen hub genes and one significant module were filtered out and selected from the PPI network. The differential expression of hub genes was verified in TCGA patients. Kaplan-Meier plot showed that high mRNA expression of enolase 2 (ENO2) was associated with short overall survival in ccRCC patients (P=0.023). High mRNA expression of cyclin D1 (CCND1) (P<0.001), fms related tyrosine kinase 1 (FLT1) (P=0.004), plasminogen (PLG) (P<0.001) and von Willebrand factor (VWF) (P=0.008) appeared to serve as favorable factors in survival. These findings indicate that the DEGs may be key genes in ccRCC pathogenesis and five genes, including ENO2, CCND1, PLT1, PLG and VWF, may serve as potential prognostic biomarkers in ccRCC.