CIAPIN1 as a Promoter of Oral Squamous Cell Carcinoma Progression

ABSTRACT Objective This study aims to investigate the relationship between the expression of cytokine‐induced apoptosis inhibitor 1 (CIAPIN1) and the development of oral squamous cell carcinoma (OSCC). Materials and Methods Bioinformatics analyzed CIAPIN1 in pan‐cancers; IHC detected CIAPIN1 expression in OSCC and healthy samples; qRT‐PCR and WB assayed CIAPIN1 mRNA and protein levels in OSCC and normal cells; MTT, scratch, transwell, flow cytometry, and WB evaluated OSCC cell viability, migration, invasion, EMT, and apoptosis after CIAPIN1 knockdown. Results CIAPIN1 abnormally expressed in multiple tumors, especially OSCC, is linked to prognosis. IHC showed elevated CIAPIN1 in OSCC tissues ( p < 0.001). qRT‐PCR and WB results showed CIAPIN1 was upregulated in CAL‐27 (qRT‐PCR: p < 0.05, WB: p < 0.05), SAS (qRT‐PCR: p < 0.05, WB: p < 0.01), and SCC9 (qRT‐PCR: p < 0.01, WB: p < 0.001) cells compared to HOK cells. After the knockdown of CIAPIN1 in SAS and SCC9 cells, MTT assays revealed reduced cell viability (SAS: p < 0.001, SCC9: p < 0.001); scratch tests showed suppressed migration ability (SAS: p < 0.01, SCC9: p < 0.001); transwell assays indicated inhibited invasion capability (SAS: p < 0.01, SCC9: p < 0.001); flow cytometry revealed increased apoptosis rates (SAS: p < 0.01, SCC9: p < 0.01); WB analysis showed reduced N‐cadherin expression and increased E‐cadherin expression (SAS for N‐cadherin: p < 0.05, SCC9 for N‐cadherin: p < 0.01; SAS for E‐cadherin: p < 0.01, SCC9 for E‐cadherin: p < 0.05), indicating CIAPIN1 promotes EMT. Conclusion CIAPIN1 contributes to the malignant progression of oral squamous cell carcinoma.