MiR-128-3p Inhibits Esophageal Squamous Cell Carcinoma Progression by Targeting TTC9
Abstract
Background: MicroRNAs (miRNAs) serve as targets for cancer diagnosis and therapy and have the potential to regulate the occurrence and progression of Esophageal squamous cell carcinoma (ESCC). Tetratricopeptide repeat domain 9 (TTC9) gene may involve in the invasion and metastasis of cancer cells. This study aimed to investigate the effects of miR-128-3p and TTC9 on ESCC progression and to elucidate the underlying molecular mechanisms. Methodology: RT-qPCR was employed to measure miR-128-3p levels in ESCC tissues and adjacent non-cancerous tissues from 50 patients, as well as in ESCC cells and normal human esophageal squamous epithelial HET1A cells. Cell metabolic activity, migration, and invasion were assessed through MTT assays, scratch healing and transwell assays; and the protein expression of epithelial-mesenchymal transition (EMT)-related markers and TTC9 was measured by Western blot. The targeted regulatory relationship between miR-128-3p and TTC9 was verified by dual-luciferase reporter assay. The effect of miR-128-3p on xenograft tumor growth in nude mice was examined, and TTC9 expression in xenograft tumors was detected by immunohistochemistry. Results: miR-128-3p expression was significantly lower in ESCC tissues and cells than in adjacent non-cancerous tissues and HET1A cells. Knocking miR-128-3p down markedly intensified the metabolic activity, invasion and moving of ESCC cells, whereas upregulating miR-128-3p excessively exhibited the opposite effect, notably suppressed tumor growth in nude mice. Through miR-128-3p’s targeted regulation, TTC9 was suppressed. Conversely, TTC9 overexpression attenuated the effects of miR-128-3p and enhanced the proliferative and metastatic capacities of ESCC cells. Additionally, miR-128-3p overexpression suppressed ESCC growth in nude mice, whereas TTC9 overexpression partially reduced this suppressive effect. Conclusion: miR-128-3p is significantly downregulated in ESCC. Overexpression of miR-128-3p suppresses the malignant biological behaviors of ESCC cells, and inhibits tumor growth in nude mice, at least in part by targeting TTC9.