DNA Microarray Analysis of HSC-3 Human Oral Squamous Cell Carcinoma Cells Following Knockdown of DDIT4

Oral squamous cell carcinomas（OSCCs）are the most common type of oral cancer and patients with OSCC have a poor prognosis and a low 5-year survival rate. Longer survival is correlated with lower expression of DNA Damage Inducible Transcript 4 （DDIT4）from certain types of cancer tissue. The primary object of this study was to explore the associated role of DDIT4 in human oral cancers. HSC-3 human oral squamous cell carcinoma cells were used to examine the effect of DDIT4 knockdown by a DDIT4 siRNA and the silencing efficiency was evaluated by quantitative real-time PCR （qRT-PCR）. DNA microarray analysis was carried out on DDIT4 siRNA transfected HSC-3 cells using the Human Exon 1.0 ST array. Ingenuity Pathway Analysis（IPA）and Gene Ontology（GO）analysis were used for bioinformatics analysis to identify potential molecular functions and related pathways of differentially expressed genes（DEGs）. The microarray results showed that 182 DEGs were upregulated, and 424 DEGs were downregulated in DDIT4-deficient HSC-3 cells. Among them, 4 genes（RNASE7, IL-24, SCD and MMP13）were selected to confirm the microarray results using qRT-PCR. IPA showed 49 related pathways are involved in DDIT4-deficient HSC-3 cells. GO analysis revealed that the GO terms of upregulated DEGs were regulation of transcription, membrane and protein binding while the GO terms of downregulated DEGs were signal transduction, membrane and protein binding. In conclusion, DDIT4 may serve as a key regulator in carcinogenesis and could be a therapeutic target in patients with OSCC.