Extrahepatic cholangiocarcinoma (CC) is an aggressive malignancy with dismal prognosis and characterized by early invasion, metastasis and postoperative recurrence. Therefore, understanding the main molecular mechanisms of this malignancy is the key for the development of novel and effective therapeutic strategies for extrahepatic CC. Foxj2 is a novel forkhead factor. Several FOX family members have been reported to play an important role in tumorigenesis and the progression of certain cancers. In this study, real-time quantitative RT-PCR (qRT-PCR), western blotting, and immunohistochemical staining were used to examine FOXJ2 expression in extrahepatic CC tissues and adjacent normal bile duct tissues. The molecular mechanisms of FOXJ2 expression and its effects on cell proliferation, migration and invasion were also explored by MTT assay, wound healing assay and Transwell assay. The relationships between the FOXJ2 expression levels, the clinicopathological factors, and patient survival were investigated. FOXJ2 mRNA and protein levels were downregulated in extrahepatic CC tissues compared to adjacent normal bile duct tissues. In addition, decreased FOXJ2 was associated disease progression in extrahepatic CC samples. Overexpression FOXJ2 expression markedly inhibited cell proliferation, migration and invasion in vitro. FOXJ2 is a transcription factor that has been reported to induce epithelial-mesenchymal transition (EMT). These findings indicated that FOXJ2 gene played a tumor suppressor role in extrahepatic CC, which proposed this gene as a new therapeutic target for extrahepatic CC patients.

MicroRNAs (miRNAs) regulate mammalian gene expression by targeting mRNAs and have key roles in several cellular processes, including differentiation, development, apoptosis and cancer pathomechanisms. Our previous studies have confirmed that a proliferation-inducing ligand (APRIL) gene is overexpressed in colorectal cancer (CRC) tumors and SW480 cells. To study the potential mechanisms of APRIL gene in the occurrence and development of the CRC, herein, we investigated whether APRILknockdown had the inhibitory effect on the growth of SW480 cells and had the simultaneous expression changes of miRNAs and mRNAs by microarrays. Our results suggest that siRNA-APRIL can effectively inhibit the growth of SW480 cells in vitro and in vivo and several miRNAs via specific pathways might be involved in regulating the phenotype of loss-of-function in APRIL-knockdown SW480 cells. Thus, our study highlights the possible mechanisms of miRNA-target regulating the function of APRIL gene in CRC cells, moreover, siRNA-APRIL holds great promise as a novel gene therapy approach for APRIL-positive CRC treatment.