MMP7, Regulated by c-Jun, is Involved in Oral Squamous Cell Carcinoma and Associated with Cancer-Related Fibroblasts Infiltration

Objective: This study aimed to analyze the expression of Matrix Metalloproteinase 7 (MMP7) and molecular mechanism at the Transcription Factor (TF) level in Oral Squamous Cell Carcinoma (OSCC). Methods: MMP7 expression was preliminarily explored in Head and Neck Squamous Cell Car-cinoma (HNSCC) in the online database, followed by functional analysis and prediction of TF of MMP7. IHC was employed to detect MMP7 levels in OSCC samples. SCC9 and 293T cells were used to explore the transcriptional and regulatory effects of predicted TF on MMP7 by reporter double luciferase assay, RT-qPCR, western blotting, and cellular immunofluorescence. Transwell and TUNEL were employed to detect the migration and apoptosis. Results: MMP7 was significantly up-regulated in HNSCC and OSCC tissues. Moreover, MMP7 was positively correlated with CAFs and significantly enriched in the signaling pathway of RNA degradation. The c-Jun pathway was also up-regulated in OSCC tissues, and predicted to be optimal TF of MMP7 with positive regulatory relationship. In OSCC, silencing and over-expression of c-Jun significantly decreased and increased the level of MMP7. Meanwhile, c-Jun affected the behavior of SCC9 cells, which showed that after c-Jun gene silencing, the ability of cell migration was weakened, while apoptosis was enhanced. When c-Jun gene was overexpressed, the migration ability was enhanced, but apoptosis was not significantly affected. Conclusion: MMP7 has been proven to be a key protein in the development of OSCC, and has the potential to become a biological marker and therapeutic target. It has been found that c-Jun could bind to the MMP7 promoter region, and the silencing or overexpression of c-Jun can positively regulate the expression of MMP7.