title: A TrkB-STAT3-miR-204-5p regulatory circuitry controls proliferation and invasion of endometrial carcinoma cells.
abstract: BACKGROUND
  We previously identified TrkB as an oncogene involved in promoting metastasis in endometrial carcinoma (EC). Here, we sought to delineate the effect of changes in TrkB expression on the global profile of microRNAs (miRNAs) in EC cells and further investigated the correlation between the expression of certain miRNA and TrkB in the clinicopathologic characteristics of EC patients.
  
  
  RESULTS
  Using quantitative reverse transcription-PCR (qRT-PCR), we found that expression of TrkB mRNA has no significant difference in transcript levels between normal endometrium and EC cells captured by laser capture microdissection, while immunohistochemistry results demonstrated a markedly higher expression of TrkB protein in EC tissues. The microRNA array showed that ectopic overexpression and knockdown of TrkB expression caused global changes in miRNA expression in EC cells. qRT-PCR results showed that elevated TrkB repressed miR-204-5p expression in EC cells. Furthermore, immunoblotting assays revealed that TrkB overexpression in IshikawaTrkB cells noticeably increased JAK2 and STAT3 phosphorylation, which, however, was aborted by TrkB knockdown in HEC-1BshTrkB cells. Moreover, ChIP assays showed that phospho-STAT3 could directly bind to STAT3-binding sites near the TRPM3 promoter region upstream of miR-204-5p. Interestingly, using bioinformatics analysis and luciferase assays, we identified TrkB was a novel target of miR-204-5p. Functionally, the MTT assays, clonogenic and Transwell assays showed that miR-204-5p significantly suppressed the clonogenic growth, migration and invasion of EC cells. Furthermore, miR-204-5p also inhibited the growth of tumor xenografts bearing human EC cells. Importantly, we found lower miR-204-5p expression was associated with advanced FIGO stages, lymph node metastasis and probably a lower chance for survival in EC patients.
  
  
  CONCLUSIONS
  This study uncovers a new regulatory loop involving TrkB/miR-204-5p that is critical to the tumorigenesis of EC and proposes that reestablishment of miR-204-5p expression could be explored as a potential new therapeutic target for this disease.
authors: Wei
authors: W
authors: Bao
authors: Hui-Hui
authors: HH
authors: Wang
authors: Fu-Ju
authors: FJ
authors: Tian
authors: Xiao-Ying
authors: XY
authors: He
authors: Mei-Ting
authors: MT
authors: Qiu
authors: Jing-Yun
authors: JY
authors: Wang
authors: Hui-Juan
authors: HJ
authors: Zhang
authors: Department of Obstetrics and Gynecology, International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine, No, 910, Hengshan Road, Shanghai 200030, China. wanglihua6504@163.com.
authors: Li-Hua
authors: LH
authors: Wang
authors: Xiao-Ping
authors: XP
authors: Wan
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation / Q000187:drug effects; D016889:Endometrial Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology* / Q000556:secondary; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D053263:Gene Regulatory Networks; D057809:HEK293 Cells; D006801:Humans; D008207:Lymphatic Metastasis; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D020813:Receptor, trkB / Q000235:genetics / Q000378:metabolism*; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D023041:Xenograft Model Antitumor Assays
chemical_list: D035683:MicroRNAs; D050796:STAT3 Transcription Factor; D020813:Receptor, trkB