Immunoglobulin (CD79a)
binding protein 1 (IGBP1) is universally overexpressed in
lung adenocarcinoma and exerts an anti-apoptotic effect by binding to PP2Ac. However, the molecular mechanism of IGBP1 overexpression is still unclear. In the present study, we used a
microRNA (
miRNA) array and TargetScan Human software to detect IGBP1-related
miRNAs that regulate IGBP1 expression. The
miRNA array analysis revealed more than 100
miRNAs that are dysregulated in early invasive
adenocarcinoma. On the other hand, in silico analysis using TargetScan Human revealed 79
miRNAs that are associated with IGBP1
protein expression. Among the
miRNAs selected by
miRNA array analysis, six (miR-34b, miR-138, miR-374a, miR-374b, miR-1909, miR-3941) were also included among those selected by TargetScan analysis. Real-time reverse transcription PCR (real-time RT-PCR) showed that the six
microRNAs were downregulated in invasive
adenocarcinoma (IGBP1+) relative to adjacent normal lung tissue (IGBP1-). Among these
microRNAs, only miR-34b and miR-3941 depressed
luciferase activity by targeting 3'UTR-IGBP1 in the
luciferase vector. We transfected miR-34b and miR-3941 into
lung adenocarcinoma cell lines (A549, PC-9), and both of them suppressed IGBP1 expression and cell proliferation. Moreover, the transfected miR-34b and miR-3941 induced apoptosis of a
lung adenocarcinoma cell line, similarly to the effect of siIGBP1
RNA. As well as miR-34b, we found that miR-3941 targeted IGBP1 specifically and was able to exclusively downregulate IGBP1 expression. These findings indicate that suppression of miR-3941 has an important role in the progression of
lung adenocarcinoma at an early stage.