SCARA5 inhibits oral squamous cell carcinoma via inactivating the STAT3 and PI3K/AKT signaling pathways

Oral squamous cell carcinoma (OSCC) is a common tumor in the world. Despite the rapid development of medical care, OSCC is also accompanied by high incidence and mortality every year. Therefore, it is still necessary to continuously develop new methods or find new targets to treat OSCC. Previous research showed that scavenger receptor class A member 5 (SCARA5) was one of the potential biomarkers of OSCC, and its expression is significantly low in OSCC. This study aimed to explore the role and related molecular mechanisms of SCARA5 in OSCC. In this study, we found that the SCARA5 expression was lower in CAL-27 and SCC-9 cells than that in human normal oral epithelial keratinocytes. SCARA5 overexpression significantly inhibited cell proliferation and induced apoptosis of CAL-27 and SCC-9 cells. In addition, SCARA5 repressed OSCC cell epithelial–mesenchymal transformation (EMT), evidenced by increased E-cadherin expression and reduced N-cadherin expression. Finally, we found that SCARA5 could suppress STAT3, PI3K, and AKT phosphorylation. Therefore, SCARA5 was related to STAT3 and PI3K/AKT signaling pathways in OSCC. In conclusion, SCARA5 inhibited the proliferation and EMT and induced the apoptosis of OSCC cells through the inhibition of STAT3 and PI3K/AKT signaling pathways, thereby exerting a tumor suppressor effect.