HMG20A was identified as a key enhancer driver associated with DNA damage repair in oral squamous cell carcinomas.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is the main type of oral cancer. Disturbing DNA repair is an invaluable way to improve the effectiveness of tumor treatment. Here, we aimed to explore the key enhancer drivers associated with DNA damage repair in OSCC cells. METHODS: Gene Set Enrichment Analysis (GSEA), Gene Set Variation Analysis (GSVA) and Kaplan-Meier analysis were applied to explore the relationship among DNA repair-related genes expression and clinical phenotypes based on The Cancer Genome Atlas (TCGA) database. HOMER software and Integrative Genomics Viewer were applied to identify and visualize enhancers using GSE120634. Toolkit for Cistrome Data Browser was applied to predict transcription factors. Human Protein Atlas Database was used to analyze the protein levels of transcription factors in OSCC and control tissues. Seventy-two OSCC patients were included in this study. qRT-PCR was used to detect transcription factor expression in OSCC and adjacent control tissues collected in this study. qRT-PCR and ChIP-qPCR were used to verify the binding of transcription factors to enhancers, and regulation of target genes transcription. Transcription factor knockdown and control cells were treated with cisplatin. CCK8 was used to detect cell viability and proliferation. Western blotting was implemented to detect the levels of DNA repair-related proteins. Transwell assay was used to detect cell invasion. RESULTS: DNA repair was positively associated with the OSCC metastatic phenotype. Patients in the cluster with high expression of DNA repair-related genes had a worse prognosis and a higher proportion of advanced stage, low-differentiation, alcohol consumption and smoking compared to the cluster with low DNA repair-related gene expression. Seventeen metastasis-specific enhancer-controlled upregulated DNA repair-related genes, with the top two upregulated genes being ADRM1 26 S proteasome ubiquitin receptor (ADRM1) and solute carrier family 12 member 7 (SLC12A7) were screened. High mobility group 20 A (HMG20A) was the key prognostic enhancer driver regulating metastasis-specific DNA repair-related genes, with higher expression in OSCC tissues than normal control tissues, and higher expression in metastatic OSCC tissues than non-metastatic OSCC tissues. HMG20A bound to the metastasis-specific enhancers of ADRM1 and SLC12A7, thereby promoting ADRM1 and SLC12A7 expression. Knockdown of HMG20A enhanced cisplatin sensitivity of cells, and inhibited OSCC cells from repairing DNA damage caused by cisplatin, as well as proliferation and invasion of OSCC cells. CONCLUSION: HMG20A was identified as the key prognostic enhancer driver regulating DNA repair in OSCC cells, providing a new therapeutic target for OSCC.

Screening of differentialy expressed saliva proteins from oral lichen planus patients by two-dimensional fluo-rescence difference gel electrophoresis and mass spectrometry / 实用口腔医学杂志

Objective:To identify differentially expressed saliva proteins of oral lichen planus(OLP)patients by two-dimensional fluo-rescence difference electrophoresis(2-D DIGE)and mass spectrometry(MS).Methods:3 pairs of saliva samples from OLP patients and matched healthy adults were collected.Saliva proteins were separated by 2-D DIGE and identified by liquid chromatography-mass spectrometry(LC-MS).Results:SDS-PAGE examination showed that the electrophoresis bands were clear and protein loss was rare. Protein dots were highly reproducible by 2-D DIGE.In average,the abundance of (31 7 ±71 )saliva protein spots were found in OLP pa-tients.4 highly reproducible spots were identified to be secretory IgA1 ,zincα-2-glycoprotein,salivary amylase and serum albumin by LC-MS and they were at higher level in OLP patients than those in the healthy controls.Conclusion:Secretory IgA1 ,zincα-2-glyco-protein,salivary amylase and serum albumin are highly expressed in the saliva of OLP patients,and may be related to the occurrence and development of oral lichen planus.