Dysregulation of the mitogen granulin in human cancer through the miR-15/107 microRNA gene group.
Granulin (GRN) is a potent mitogen and growth factor implicated in many human cancers, but its regulation is poorly understood. Recent findings indicate that GRN is regulated strongly by the microRNA miR-107, which functionally overlaps with miR-15, miR-16, and miR-195 due to a common 5' sequence critical for target specificity. In this study, we queried whether miR-107 and paralogs regulated GRN in human cancers. In cultured cells, anti-argonaute RNA coimmunoprecipitation with downstream microarray analyses indicates that GRN mRNA is directly targeted by numerous miR-15/107 miRNAs. We further tested this association in human tumors. MiR-15 and miR-16 are known to be downregulated in chronic lymphocytic leukemia (CLL). Using pre-existing microarray datasets, we found that GRN expression is higher in CLL relative to nonneoplastic lymphocytes (P < 0.00001). By contrast, other prospective miR-15/miR-16 targets in the dataset (BCL-2 and cyclin D1) were not upregulated in CLL. Unlike in CLL, GRN was not upregulated in chronic myelogenous leukemia (CML) where miR-107 paralogs are not known to be dysregulated. Prior studies have shown that GRN is also upregulated, and miR-107 downregulated, in prostate carcinoma. Our results indicate that multiple members of the miR-107 gene group indeed repress GRN protein levels when transfected into prostate cancer cells. At least a dozen distinct types of cancer have the pattern of increased GRN and decreased miR-107 expression. These findings indicate for the first time that the mitogen and growth factor GRN is dysregulated via the miR-15/107 gene group in multiple human cancers, which may provide a potential common therapeutic target.
Wang
Wang-Xia
WX
Department of Pathology and Division of Neuropathology, University of Kentucky Medical Center, University of Kentucky, Lexington, Kentucky 40536-0230, USA.
Kyprianou
Natasha
N
Wang
Xiaowei
X
Nelson
Peter T
PT
D045744:Cell Line, Tumor; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics*; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D009369:Neoplasms / Q000235:genetics* / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D000077153:Progranulins; D011471:Prostatic Neoplasms / Q000235:genetics / Q000473:pathology
D036341:Intercellular Signaling Peptides and Proteins; C549045:MIRN107 microRNA, human; C505361:MIRN15 microRNA, human; D035683:MicroRNAs; D000077153:Progranulins