title: RIPK4 is downregulated in poorly differentiated tongue cancer and is associated with migration/invasion and cisplatin-induced apoptosis.
abstract: BACKGROUND
  RIPK4 is essential for the identification of keratinocyte differentiation and cutaneous inflammation. The mechanisms involved in the tumorigenesis of tongue squamous cell carcinoma (TSCC) have not been well characterized yet.
  
  
  OBJECTIVE
  To assess RIPK4 expression in various differentiated TSCC and to determine its basic biological function.
  
  
  METHODS
  Overall, 109 human samples (36 normal tongue tissues and 73 surgically excised TSCC tissues with different degrees of differentiation) were collected for the present study. The expression of RIPK4 was assessed by real time PCR and immunocytochemistry. Multivariate logistic regression analysis was used to investigate the association between RIPK4 and clinical characteristics. In vitro analyses by scratch wound healing assay and invasion assays, as well as confocal laser scanning microscopy and flow cytometry analysis were performed using the Tca-8113 tongue cancer cell line. Cisplatin sensitivity analysis and cisplatin-induced activation of caspase 8 analysis were also performed.
  
  
  RESULTS
  A significantly higher level of RIPK4 was found in well-differentiated TSCC samples than in the poorly differentiated ones (p<0.01). Male patients had relatively higher levels of RIPK4 (p=0.03). RIPK4 levels were also increased in older patients. In vitro, RIPK4 reduced the migration and invasion of the Tca-8113 cell line, but did not affect apoptosis and cell cycle. Both RIPK4 up or downregulation induced cell sensitivity to cisplatin, determining cell apoptosis.
  
  
  CONCLUSIONS
  In the present work we found a correlation between RIPK4 expression and TSCC degree of differentiation, age, and gender. The better understanding of the molecular mechanism of RIPK4 in TSCC may provide a promising biomarker for tongue cancer prognosis and treatment.
authors: The Affiliated Hospital of Stomatology, College Of Medicine, Zhejiang University, Hangzhou, Zhejiang - China.
authors: Xinhua
authors: X
authors: Wang
authors: Wenyuan
authors: W
authors: Zhu
authors: Yi
authors: Y
authors: Zhou
authors: Wanlian
authors: W
authors: Xu
authors: Huiming
authors: H
authors: Wang
mesh_terms: D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D002294:Carcinoma, Squamous Cell / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D002454:Cell Differentiation / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D002945:Cisplatin / Q000627:therapeutic use*; D015536:Down-Regulation; D005260:Female; D006258:Head and Neck Neoplasms / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D006801:Humans; D008297:Male; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D000077195:Squamous Cell Carcinoma of Head and Neck; D014062:Tongue Neoplasms / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D014162:Transfection
chemical_list: D000970:Antineoplastic Agents; C417187:RIPK4 protein, human; D017346:Protein Serine-Threonine Kinases; D002945:Cisplatin