Bioinformatic Prediction of Novel Signaling Pathways of Apoptosis-inducing Factor, Mitochondrion-associated 3 (AIFM3) and Their Roles in Metastasis of Cholangiocarcinoma Cells.

Abstract

We previously demonstrated that a mitochondrial protein, apoptosis-inducing factor, mitochondrion-associated 3 (AIFM3) is over-expressed in cholangiocarcinoma (CCA) and its serum levels can be a prognostic biomarker for CCA. To elucidate the functional roles of AIFM3 in CCA progression, we aimed to determine the signaling pathways of AIFM3 in CCA. AIFM3 gene in CCA cells was silenced and AIFM3-related proteins were identified using mass spectrometry and bioinformatics tools. The relationships between AIFM3 and 441 related proteins were explored. To validate the functions of AIFM3, transwell migration/invasion assays were used. Bioinformatic analyses predicted that AIFM3 interacts with formin-like protein 3 (FMNL3) and is involved in tumor cell motilities. Online database analysis revealed higher AIFM3 mRNA expression levels in CCA, particularly with lymph node metastasis. After AIFM3 gene silencing, CCA cell migration/invasion was significantly decreased (p<0.001). Furthermore, AIFM3 expression levels were significantly associated with lymph node metastasis (p=0.0009) and shorter survival time (p=0.020). The AIFM3 signaling pathway is mediated via FMNL3 and involved in metastasis, suggesting that AIFM3 might be a molecular target to prevent CCA metastasis.