circIGHG-induced epithelial-to-mesenchymal transition promotes oral squamous cell carcinoma progression via miR-142-5p/IGF2BP3 signaling.

Circular RNAs are a new member of endogenously produced noncoding RNAs that have been characterized as key regulators of gene expression in a variety of malignances. However, the role of circRNA in oral squamous cell carcinoma (OSCC) remains largely unknown. In this study, we identified unique circRNA that regulate OSCC progression and metastasis and pave roads for future research in early diagnosis, prevention, and treatment of OSCC. Transcriptomic analyses identified a circRNA derived from immunoglobulin heavy chain G locus (circIGHG) as significantly upregulated in OSCC and positively associated with poor prognosis of OSCC. circIGHG directly bound miR-142-5p and consequently elevated IGF2BP3 activity. Knockdown of circIGHG led to impaired expression of IGF2BP3 and attenuated aggressiveness of OSCC cells. EMT was the main mechanism through which circIGHG/IGF2BP3 promotes metastasis of OSCC. Overall, these results demonstrate that circIGHG plays pivotal role in OSCC development and metastasis and has potential to serve as a biomarker and therapeutic target for early-stage diagnosis and treatment of OSCC.