title: Targeting STAT3/miR-21 axis inhibits epithelial-mesenchymal transition via regulating CDK5 in head and neck squamous cell carcinoma.
abstract: BACKGROUND
  Abnormal activation of STAT3 and miR-21 plays a vital role in progression and invasion of solid tumors. The cyclin-dependent kinase 5 (CDK5) is reported to contribute to cancer metastasis by regulating epithelial-mesenchymal transition (EMT). However, the role of STAT3/miR-21 axis and CDK5 in head and neck squamous cell carcinoma remains unclear.
  
  
  METHODS
  We measured the expression of miR-21, CDK5 and EMT markers in 60 HNSCC tumor samples. We used Immunohistochemistry and in situ hybridization assay to examine the role of STAT3/miR-21 axis and CDK5 activation in the invasiveness of HNSCC. The clinical survival relevance was analyzed by Kaplan-Meier analysis and univariate/multivariate COX regression model. Multiple approaches including scratch, transwell chamber assay and other molecular biology techniques were used to validate the anti-invasion effect of targeting miR-21 in Tca8113 and Hep-2 cell lines in vitro. Furthermore, whether miR-21 depletion inhibits HNSCC invasion in vivo was confirmed in Tca8113 xenograft tumor model.
  
  
  RESULTS
  The expression of miR-21 and CDK5 were significantly correlated with lymph node metastasis in HNSCC. Hep-2 and Tca8113 cell lines showed co-overexpression of miR-21 and CDK5. WP1066 or asON-miR-21 treatment depleted miR-21 and CDK5 expression and significantly inhibited migration or invasion in Hep-2 and Tca8113 cells. The expression levels of CDK5/p35, N-cadherin, vimentin, β-catenin were inhibited while E-cadherin level was increased by miR-21 depletion in vitro and in vivo. Conversely, ectopic CDK5 overexpression significantly induced tumor cell motility and EMT. Moreover, ectopic CDK5 overexpression in Hep-2 and Tca8113 cells rescued the observed phenotype after miR-21 silencing or WP1066 treatment.
  
  
  CONCLUSIONS
  miR-21 cooperates with CDK5 to promote EMT and invasion in HNSCC. This finding suggests that CDK5 may be an important cofactor for targeting when designing metastasis-blocking therapy by targeting STAT3/miR-21 axis with STAT3 inhibitor or miR-21 antisense oligonucleotide. This is the first demonstration of the novel role of STAT3/miR-21 axis and CDK5/CDK5R1 (p35) in metastasis of HNSCC.
authors.affiliation: The Maxillary Facial and Otorhinolaryngology Head & Neck Surgery, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huanhuxi Road, Tiyuanbei, Hexi District, Tianjin, TJ, 300060, China. 416638617sss@163.com.
authors.forename: Shan-Shan
authors.initials: SS
authors.lastname: Sun
authors.affiliation: The Maxillary Facial and Otorhinolaryngology Head & Neck Surgery, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huanhuxi Road, Tiyuanbei, Hexi District, Tianjin, TJ, 300060, China. byron2000zhou@sina.com.
authors.forename: Xuan
authors.initials: X
authors.lastname: Zhou
authors.affiliation: The Maxillary Facial and Otorhinolaryngology Head & Neck Surgery, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huanhuxi Road, Tiyuanbei, Hexi District, Tianjin, TJ, 300060, China. 2008huang.yuanyuan@163.com.
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Huang
authors.affiliation: The Maxillary Facial and Otorhinolaryngology Head & Neck Surgery, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huanhuxi Road, Tiyuanbei, Hexi District, Tianjin, TJ, 300060, China. kong.lp@foxmail.com.
authors.forename: Ling-Ping
authors.initials: LP
authors.lastname: Kong
authors.affiliation: Basic Medical Research Center, Tianjin Medical University, Qixiangtai Road, Heping District, Tianjin, TJ, 300070, China. mei_10668@163.com.
authors.forename: Mei
authors.initials: M
authors.lastname: Mei
authors.affiliation: The Maxillary Facial and Otorhinolaryngology Head & Neck Surgery, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huanhuxi Road, Tiyuanbei, Hexi District, Tianjin, TJ, 300060, China. guowenyu920@163.com.
authors.forename: Wen-Yu
authors.initials: WY
authors.lastname: Guo
authors.affiliation: The Maxillary Facial and Otorhinolaryngology Head & Neck Surgery, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huanhuxi Road, Tiyuanbei, Hexi District, Tianjin, TJ, 300060, China. 1007101880@qq.com.
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Zhao
authors.affiliation: Basic Medical Research Center, Tianjin Medical University, Qixiangtai Road, Heping District, Tianjin, TJ, 300070, China. renyu0425@yahoo.com.
authors.forename: Yu
authors.initials: Y
authors.lastname: Ren
authors.affiliation: Department of Clinical Cancer Prevention, Division of Cancer Prevention and Population Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA. qshen@mdanderson.org.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Shen
authors.affiliation: The Maxillary Facial and Otorhinolaryngology Head & Neck Surgery, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huanhuxi Road, Tiyuanbei, Hexi District, Tianjin, TJ, 300060, China. lunzhangchina@163.com.
authors.forename: Lun
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D002294:Carcinoma, Squamous Cell / Q000201:enzymology* / Q000235:genetics / Q000556:secondary; D045744:Cell Line, Tumor; D051360:Cyclin-Dependent Kinase 5 / Q000235:genetics / Q000378:metabolism*; D058750:Epithelial-Mesenchymal Transition; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D006258:Head and Neck Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D006801:Humans; D008207:Lymphatic Metastasis; D008819:Mice, Nude; D035683:MicroRNAs / Q000235:genetics*; D011725:Pyridines / Q000494:pharmacology; D034622:RNA Interference; D050796:STAT3 Transcription Factor / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020032:Tyrphostins / Q000494:pharmacology; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D011725:Pyridines; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D020032:Tyrphostins; C519885:WP1066; D051360:Cyclin-Dependent Kinase 5; C495905:CDK5 protein, human