MicroRNA miR-199a* regulates the MET proto-oncogene and the downstream extracellular signal-regulated kinase 2 (ERK2).
MicroRNAs (miRNAs) constitute a class of small noncoding RNAs that play important roles in a variety of biological processes including development, apoptosis, proliferation, and differentiation. Here we show that the expression of miR-199a and miR-199a* (miR-199a/a*), which are processed from the same precursor, is confined to fibroblast cells among cultured cell lines. The fibroblast-specific expression pattern correlated well with methylation patterns: gene loci on chromosome 1 and 19 were fully methylated in all examined cell lines but unmethylated in fibroblasts. Transfection of miR-199a and/or -199a* mimetics into several cancer cell lines caused prominent apoptosis with miR-199a* being more pro-apoptotic. The mechanism underlying apoptosis induced by miR-199a was caspase-dependent, whereas a caspase-independent pathway was involved in apoptosis induced by miR-199a* in A549 cells. By employing microarray and immunoblotting analyses, we identified the MET proto-oncogene as a target of miR-199a*. Studies with a luciferase reporter fused to the 3'-untranslated region of the MET gene demonstrated miR-199a*-mediated down-regulation of luciferase activity through a binding site of miR-199a*. Interestingly, extracellular signal-regulated kinase 2 (ERK2) was also down-regulated by miR-199a*. Coordinated down-regulation of both MET and its downstream effector ERK2 by miR-199a* may be effective in inhibiting not only cell proliferation but also motility and invasive capabilities of tumor cells.
Kim
Seonhoe
S
Gene2Drug Research Center, Bioneer Corporation, and National Genome Information Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea.
Lee
Ui Jin
UJ
Kim
Mi Na
MN
Lee
Eun-Ju
EJ
Kim
Ji Young
JY
Lee
Mi Young
MY
Choung
Sorim
S
Kim
Young Joo
YJ
Choi
Young-Chul
YC
D017209:Apoptosis; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004247:DNA / Q000737:chemistry; D019175:DNA Methylation; D005347:Fibroblasts / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006367:HeLa Cells; D006801:Humans; D035683:MicroRNAs / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D008954:Models, Biological; D009361:Neoplasm Invasiveness; D000090063:Proto-Oncogene Mas; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism*; D012313:RNA / Q000737:chemistry
C000715470:MAS1 protein, human; D035683:MicroRNAs; D000090063:Proto-Oncogene Mas; D012313:RNA; D004247:DNA; D019859:Proto-Oncogene Proteins c-met; D019950:Mitogen-Activated Protein Kinase 1