Evaluation of miR-429 as a novel serum biomarker for pancreatic ductal adenocarcinoma and analysis its tumor suppressor function and target genes.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of cancer. Various microRNAs have been identified to play an important role in PDAC. The study aimed to explore the role of miR-429 in PDAC.The expression and prognostic value of miR-429 were first analyzed using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Next, miR-429 expression was evaluated in the tissues and serum of 90 patients with PDAC. CCK8, SRB, wound healing and transwell assays were used to determine the effect of miR-429 on the proliferation, invasion, and migration of PDAC cells, respectively. Weighted gene co-expression network analysis (WGCNA), correlation analysis, TargetScan, and miRDB databases were used to screen and identify the target genes of miR-429.The results revealed that the expression of miR-429 was downregulated in PDAC tissues and the serum compared with those in normal tissues and the serum of healthy volunteers, respectively. The decreased expression of miR-429 was significantly associated with shorter overall survival. The overexpression of miR-429 significantly inhibited the proliferation, invasion, and migration of PDAC cells. Potential target genes of miR-429 were identified using WGCNA and bioinformatics analysis, and the results showed that cadherin 11 (CDH11), inositol polyphosphate-4-phosphatase type I (INPP4A), laminin gamma 1 (LAMC1), low density lipoprotein receptor-related protein 1 (LRP1), and quaking (QKI) were potential target genes of miR-429 in PDAC. Lower expression of CDH11 and QKI was associated with a more favorable prognosis in patients with PDAC. The overexpression of miR-429 could inhibit the expression of CDH11 and QKI. A nomogram model, involving miR-429, CDH11, and QKI, was subsequently constructed to determine their ability to accurately predict overall and disease-free survival in patients with PDAC.Taken together, miR-429 is involved in the development and progress of PDAC. MiR-429 could be recommended as a prognostic biomarker and therapeutic indicator in PDAC diagnosis.