Activation of Toll-like receptor-9 promotes cellular migration via up-regulating MMP-2 expression in oral squamous cell carcinoma

• Published in: PloS one Vol. 9; no. 3; p. e92748
• Main Authors: Ruan, Min, Zhang, Zun, Li, Siyi, Yan, Min, Liu, Shengwen, Yang, Wenjun, Wang, Lizheng, Zhang, Chenping
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 21.03.2014; Public Library of Science (PLoS)
• Subjects: Analysis; Assaying; Binding; Cancer; Cancer metastasis; Cancer therapies; Carcinoma, Squamous Cell - genetics; Carcinoma, Squamous Cell - metabolism; Cell activation; Cell adhesion & migration; Cell Line, Tumor; Cell migration; Cell Movement - drug effects; CpG islands; Deoxyribonucleic acid; DNA; Enzyme Activation - drug effects; Enzyme-linked immunosorbent assay; Ethics; Gelatin; Gelatinase A; Gene Expression; Health aspects; Humans; Immune system; Laboratories; Matrix Metalloproteinase 2 - genetics; Matrix Metalloproteinase 2 - metabolism; Medical prognosis; Medical research; Medicine; Medicine and Health Sciences; Metastases; Metastasis; Molecular modelling; Mouth Neoplasms - genetics; Mouth Neoplasms - metabolism; Oligodeoxyribonucleotides - pharmacology; Oligonucleotides; Oncology; Oral cancer; Oral squamous cell carcinoma; Pretreatment; Prognosis; Proteins; Receptors; Secretion; Signal Transduction; Signaling; siRNA; Squamous cell carcinoma; Studies; TLR9 protein; Toll-Like Receptor 9 - genetics; Toll-Like Receptor 9 - metabolism; Toll-like receptors; Transcription Factor AP-1 - metabolism; Transcription factors; Transfection; Wound healing
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0092748

Activation of Toll like receptors (TLRs) signaling has been implicated in promoting malignant cell invasion and metastatic potential. Previously we demonstrated that increased TLR-9 expression predicted poor survival in oral cancer patients. The objective of this study is to further investigate the roles and potential molecular mechanisms of TLR-9 signaling in human oral cancer cell invasion. Cell migration, invasion and protein expression were detected by wound healing assay, Transwell chambers model and western blot. The secretion and activity levels of metalloproteinases-2/9 were quantified by ELISA and Gelatin zymography. EMSA and ChIP assays were employed to detect the activity of AP-1signal pathway. TLR-9 siRNA transfection was used to regulate the expression and activity of TLR-9 in oral cancer cell line HB cells. The results of both wound healing assay and in vitro Transwell assay revealed that activation of TLR-9 induced dose- and time- dependent migration and invasion of HB cells. An increased expression, secretion and activity of MMP-2 were observed upon the treatment of CpG-ODN. The TLR-9 signaling-mediated MMP-2 expression appeared to be a consequence of AP-1 activation, because that their DNA binding activity was enhanced by CpG-ODN treatment. All these influences were efficiently repressed by the knockdown of TLR-9 through siRNA or pretreatment of an AP-1 inhibitor. Activation of TLR-9 signaling could promote human oral cancer HB cells invasion with the induction of MMP-2 presentation by attenuating AP-1 binding activity, suggesting a novel anti-metastatic application for TLR-9 targeted therapy in oral cancer in the future.