Autoregulatory loop between TGF-β1/miR-411-5p/SPRY4 and MAPK pathway in rhabdomyosarcoma modulates proliferation and differentiation.
The origin of rhabdomyosarcoma (RMS) remains controversial. However, specific microRNAs (miRNAs) are downregulated in RMS and it is possible that re-expression of these miRNAs may lead to differentiation. Transforming growth factor-β1 (TGF-β1) is known to block differentiation of RMS. We therefore analyzed miRNA microarrays of RMS cell lines with or without TGF-β1 knockdown and identified a novel anti-oncogene miR-411-5p. Re-expression of miR-411-5p inhibited RMS cell proliferation in vitro and tumorigenicity in vivo. Using a luciferase reporting system and sequence analysis, the potential target of miR-411-5p was identified as sprouty homolog 4 (SPRY4), which inhibits protein kinase Cα-mediated activation of mitogen-activated protein kinases (MAPKs), especially p38MAPK phosphorylation. These results revealed an inverse correlation between TGF-β1/SPRY4 and miR-411-5p levels. SPRY4 small interfering RNA and miR-411-5p both activated p38MAPK phosphorylation and also promoted apoptosis and myogenic differentiation, indicated by increased caspase-3, myosin heavy chain, and myosin expression. SPRY4 and miR-411 mRNA levels correlated with TGF-β1 expression levels in RMS tissues, which was confirmed by immunohistochemical staining for TGF-β1, SPRY4, and phosphorylated p38MAPK proteins. Overall, these results indicate that miR-411-5p acts as an RMS differentiation-inducing miRNA prompting p38MAPK activation via directly downregulating SPRY4. These results establish an autoregulatory loop between TGF-β1/miR-411-5p/SPRY4 and MAPK in RMS, which governs the switch between proliferation and differentiation.
Laboratory Animal Research Center, Soochow University School of Medicine, Suzhou 215123, China.
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M
Sun
Department of Pathology, Soochow University School of Medicine, Suzhou 215123, China.
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F
Huang
Department of Plastic Surgery, Second Affiliated Hospital, Soochow University, Suzhou 215004, China.
D
D
Yu
Department of Pathology, Soochow University School of Medicine, Suzhou 215123, China.
Y
Y
Zhang
Department of Oncology, First Affiliated Hospital, Soochow University, Suzhou 215006, China.
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H
Xu
Department of Surgery, First Affiliated Hospital, Soochow University, Suzhou 215006, China.
L
L
Zhang
Department of Osteology, Second Affiliated Hospital, Soochow University, Suzhou 215004, China.
L
L
Li
Department of Pathology, Soochow University School of Medicine, Suzhou 215123, China.
L
L
Dong
Department of Pathology, Soochow University School of Medicine, Suzhou 215123, China.
L
L
Guo
Department of Pathology, Soochow University School of Medicine, Suzhou 215123, China.
S
S
Wang
D000818:Animals; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D025461:Feedback, Physiological; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter; D006801:Humans; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D009368:Neoplasm Transplantation; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010766:Phosphorylation; D051571:Protein Kinase C-alpha / Q000235:genetics / Q000378:metabolism; D012208:Rhabdomyosarcoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D015398:Signal Transduction; D053773:Transforming Growth Factor beta1 / Q000235:genetics* / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics* / Q000378:metabolism
D035683:MicroRNAs; D009419:Nerve Tissue Proteins; C499037:Spry4 protein, mouse; D053773:Transforming Growth Factor beta1; D008156:Luciferases; D051571:Protein Kinase C-alpha; D048051:p38 Mitogen-Activated Protein Kinases