STAT3 interactome predicts presence of proteins that regulate immune system in oral squamous cell carcinoma

Abstract

Objectives

Signal transducer and activator of transcription 3 (STAT3) is one of the key proliferation mechanism–related proteins that helps in oral squamous cell carcinoma (OSCC) progression. Immune evasion by STAT3 is mediated by the JAK2/STAT3/PDL1 signaling axis. Based on previous findings, we hypothesized that STAT3-binding partners participate in the inhibition of anti-tumor activity in OSCC.

Methods

A 3D cancer-immune co-culture model was constructed using oral cancer cell lines SCC4, SCC9, SCC25, and CAL27 and normal oral cell line OKF6. The cells were co-cultured with natural killer (NK-92) and Jurkat cells. The target protein STAT3 was chosen based on SWATH data, and co-immunoprecipitation (Co-IP)-based proteomics was conducted. The Co-IP LC-MS/MS output was analysed to determine the protein interaction network, gene ontology, pathway analysis, and protein cluster annotation.

Results

STAT3 in oral cancer cell lines interacts with the epidermal growth factor receptor (EGFR) and other proteins that participate in proliferation and immune mechanisms. Proteome analysis showed that some STAT3-binding proteins found in this study are known immune system regulators.

Conclusion

Overall, STAT3 interactive proteins regulate the immune system in oral squamous cell carcinoma cells.