title: CCL21-CCR7 promotes the lymph node metastasis of esophageal squamous cell carcinoma by up-regulating MUC1.
abstract: BACKGROUND
  CCR7 and MUC1 are correlated with lymph node metastasis in ESCC, but the role of MUC1 in the CCR7-induced lymphatic metastasis and the underlying molecular mechanism is still unclear.
  
  
  METHODS
  The expression of CCR7 and MUC1 was detected in the ESCC samples by IHC, and the clinical significance of CCR7 and MUC1 in ESCC was analyzed. The expression of CCR7 and MUC1 in ESCC cell lines was detected by qRT-PCR and western blot. The effect of CCL21 on the migration and invasion of ESCC cells was determined by transwell assay. The activity of MUC1 promoter was determined by luciferase reporter assay. The activation of Erk, Akt and Sp1 was detected by western blot and the binding of Sp1 to the MUC1 promoter was determined by ChIP.
  
  
  RESULTS
  The co-expression of CCR7 and MUC1 was detected in 153 ESCC samples by IHC, and both were correlated with lymph node metastasis, regional lymphatic recurrence and poor prognosis. Correspondingly, increasing levels of MUC1 mRNA and protein were detected in the ESCC cell lines KYSE410 and Eca9706 after treatment with CCL21 in a time- and dose-dependent manner. Furthermore, silencing MUC1 could remarkably suppress the invasion and migration of ESCC cells induced by CCL21. Moreover, heterologous CCR7 promoted the invasion and migration of KYSE150 and up-regulated MUC1 expression. Increasing levels of activated ERK1/2 and Akt were detected in KYSE410 after treating the cells with CCL21, and inhibiting the activation of ERK1/2 but not Akt caused the increased transcription of MUC1. Finally, the phosphorylation of Sp1 induced by ERK1/2 and subsequent increases in the binding of Sp1 to the muc1 promoter at -99/-90 were confirmed to cause the up-regulation of MUC1 induced by CCL21-CCR7.
  
  
  CONCLUSIONS
  Our findings suggested that MUC1 plays an important role in CCL21-CCR7-induced lymphatic metastasis and may serve as a therapeutic target in ESCC.
authors.affiliation: Department of Thoracic Surgery of Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, China. legendsm01@163.com.
authors.forename: Mo
authors.initials: M
authors.lastname: Shi
authors.affiliation: Department of Thoracic Surgery of Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, China. 1021075579@qq.com.
authors.forename: Dong
authors.initials: D
authors.lastname: Chen
authors.affiliation: Department of Oncology of Jinan Central Hospital Affiliated to Shandong University, Jinan, 250013, China. 773776965@qq.com.
authors.forename: Dong
authors.initials: D
authors.lastname: Yang
authors.affiliation: Department of Thoracic Surgery of Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, China. Liuxy6638@126.com.
authors.forename: Xiang-Yan
authors.initials: XY
authors.lastname: Liu
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement; D054421:Chemokine CCL21 / Q000096:biosynthesis* / Q000235:genetics; D004938:Esophageal Neoplasms / Q000235:genetics* / Q000473:pathology; D000077277:Esophageal Squamous Cell Carcinoma; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008198:Lymph Nodes; D008207:Lymphatic Metastasis / Q000235:genetics*; D018396:Mucin-1 / Q000096:biosynthesis* / Q000235:genetics; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000235:genetics / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis; D054400:Receptors, CCR7 / Q000096:biosynthesis* / Q000235:genetics
chemical_list: C515478:CCL21 protein, human; C515370:CCR7 protein, human; D054421:Chemokine CCL21; C060192:MUC1 protein, human; D018396:Mucin-1; D012333:RNA, Messenger; D054400:Receptors, CCR7