Upregulation of GRIM-19 suppresses the growth of oral squamous cell carcinoma in vitro and in vivo.

Constitutive activation of the signal transducer and activator of transcription 3 (STAT3) and its upregulation contribute to the progression and metastasis of several different tumor types. The gene associated with retinoid‑interferon‑induced mortality-19 (GRIM-19) is known to functionally interact with STAT3 and inhibit its transcriptional activity. It has been reported that upregulation of genes associated with GRIM-19 can significantly reduce the tumor growth of several types of tumors. However, little is known in regards to its role in oral squamous cell carcinoma (OSCC). In the present study, a recombinant eukaryotic expression plasmid carrying GRIM-19 was constructed to evaluate its effects on OSCC cancer growth. Upregulation of GRIM-19 in OSCC cells significantly inhibited cell proliferation, migration and invasion in vitro and suppressed tumor growth in vivo. Moreover, we found that upregulation of GRIM-19 reduced cyclin D1, Bcl-2, vascular endothelial growth factor (VEGF) and matrix metalloproteinase-2 (MMP-2) expression whose protein is involved in STAT3 activation. Taken together, these findings suggest that GRIM-19 plays an inhibitory role in the progression of OSCC, and contribute to the future development of STAT3-based gene therapeutic approaches for OSCC.