MicroRNA Expression Profiling of Pancreatic Cancer Cell Line L3.6p1 Following B7-H4 Knockdown

Background/Aims: Co-stimulating molecule B7-H4 regulates T cell-mediated immune responses, participates in tumor immune escape, and promotes the proliferation and metastasis of pancreatic cancer cells. However, the specific mechanisms are unclear. MicroRNAs (miRNAs) participated in the pathogenesis and progression of cancer. Methods: In this study, a microarray technique was used to screen B7-H4-related differentially expressed miRNAs in a pancreatic cancer cell line find those associated with pancreatic cancer. Using a miRCURY (TM) LNA Array approach, we compared the miRNA expression profiles of L3.6p1 pancreatic cancer cells transfected with B7-H4 siRNA for 72 h with those transfected with non-target siRNAs. Results: B7-H4 siRNA significantly up-regulated 57 miRNAs and down-regulated 14 miRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway analysis of predicted miRNA targets showed that these genes were mainly involved in protein binding, pathways in cancer, mitogen-activated protein kinase (MAPK) signaling pathway, and phosphatidylinositol 3-kinase-Akt (PI3K-Akt) signaling pathway. Conclusions: This is the first description of target genes of B7-H4, showing that miRNAs participate in the B7-H4 mediated regulation of oncogenicity and pathogenesis of pancreatic cancer. These results may help us better understand the role of B7-H4 in the progression of pancreatic cancer and its possible mechanisms. We also provide novel biomarkers for potential treatments of pancreatic cancer.