MicroRNA-125a inhibits cell growth by targeting glypican-4.
Heparan sulfate proteoglycan (HSPG), such as glypican, plays a role as a co-receptor for growth factor to influence cells proliferation. However the mechanism is still vague. Micro-RNAs (miRNAs) regulate cell proliferation. Their capacity to direct the translation and stability of targeted transcripts can dramatically influence cellular physiological function. To explore how the function of glypican is regulated involved in cell proliferation, glypican-4 was chosen with a bioinformatics search identifying targeting seed sequences for miR-125a within the 3'-untranslated regions (3'UTR). Indeed, luciferase constructs containing the 3'UTR of glypican-4 demonstrated around 54% less activity in miR-125a expressing cells relative to the controls. The expression of glypican-4 at both the transcript and protein level was down-regulated by transition trasfection of miR-125a in the human embryonic kidney cell line 293T (HEK293T). Although cell proliferation of HEK293T was not influenced by the silence of glypican-4, DNA synthesis in response to FGF2 in the cells was attenuated by knockdown of glypican-4 using siRNA technique. Further study showed that phosphorylation of ERK(1/2) and AKT was suppressed by overexpressing miR-125a, whereas the suppressed MAPK and AKT signaling could be recovered by anti-miR-125a treatment. Both DNA synthesis and cell proliferation were impaired by the inhibitor of ERK(1/2) signaling. MTT assay demonstrated that the cell proliferation was impaired by miR-125a overexpression, however, rescued by anti-miR-125a in HEK293T cells. These results disclosed new function of miR-125a by targeting gene glypican-4 in cell growth process and illustrated the feasibility of using miRNAs as a therapeutic strategy to suppress cells proliferation.
Glycochemistry & Glycobiology Lab, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
Chao
C
Feng
Jie
J
Li
Jinlan
J
Ruan
Kan
K
Ding
D020413:3' Untranslated Regions / Q000502:physiology; D049109:Cell Proliferation; D016222:Fibroblast Growth Factor 2 / Q000235:genetics / Q000378:metabolism; D055785:Gene Knockdown Techniques; D053673:Glypicans / Q000096:biosynthesis* / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D020935:MAP Kinase Signaling System / Q000502:physiology; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis / Q000502:physiology*; D055550:Protein Stability; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism
D020413:3' Untranslated Regions; C492044:GPC4 protein, human; D053673:Glypicans; C531888:MIRN125 microRNA, human; D035683:MicroRNAs; D016222:Fibroblast Growth Factor 2; D051057:Proto-Oncogene Proteins c-akt; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3