Fucoidan affects oral squamous cell carcinoma cell functions in vitro by regulating FLNA-derived circular RNA.

Oral squamous cell carcinoma (OSCC) is one of the most common cancer types, with a high annual incidence. Although chemotherapy contributes to suppressing OSCC tumorigenesis, the available treatments result in poor prognosis because of local recurrence and regional lymph node metastasis. Thus, it is necessary to discover novel and safe drugs with greater effectiveness and fewer side effects. Fucoidan is a component of the cell wall of brown seaweed that has been shown to produce a wide range of biological activities. The present study aimed to investigate the effectiveness of fucoidan in treating OSCC. In in vitro studies, we found that fucoidan inhibited OSCC growth and suppressed migration and invasion of OSCC cells. In addition, the potential interaction between fucoidan and filamin A (FLNA)-derived circular RNA (circFLNA) was predicted using bioinformatics databases and then confirmed in OSCC samples and cell lines. Indeed, fucoidan increased the expression of circFLNA in OSCC cell lines. Furthermore, both fucoidan and circFLNA could mediate the expression of key proteins related to cell growth, apoptosis, migration, and invasion. In conclusion, our research demonstrated that fucoidan might be considered as a potential natural drug in the treatment of OSCC patients by targeting circFLNA.