title: Cathepsin B as a potential prognostic and therapeutic marker for human lung squamous cell carcinoma.
abstract: BACKGROUND
  The lung squamous cell carcinoma survival rate is very poor despite multimodal treatment. It is urgent to discover novel candidate biomarkers for prognostic assessment and therapeutic targets to lung squamous cell carcinoma (SCC).
  
  
  RESULTS
  Herein a two-dimensional gel electrophoresis and ESI-Q-TOF MS/MS-based proteomic approach was used to identify differentially expressed proteins between lung SCC and adjacent normal tissues. 31 proteins with significant alteration were identified. These proteins were mainly involved in metabolism, calcium ion binding, signal transduction and so on. Cathepsin B (CTSB) was one of the most significantly altered proteins and was confirmed by western blotting. Immunohistochemistry showed the correlation between higher CTSB expression and lower survival rate. No statistically significant difference between CTSB-shRNA treated group and the controls was observed in tumor volume, tumor weight, proliferation and apoptosis. However, the CTSB-shRNA significantly inhibited tumor metastases and prolonged survival in LL/2 metastatic model. Moreover, CTSB, Shh and Ptch were up-regulated in patients with metastatic lung SCC, suggesting that hedgehog signaling might be activated in metastatic lung SCC which could affect the expression of CTSB that influence the invasive activity of lung SCC.
  
  
  CONCLUSIONS
  These data suggested that CTSB might serve as a prognostic and therapeutic marker for lung SCC.
authors.forename: Fengming
authors.initials: F
authors.lastname: Gong
authors.affiliation: Department of Medical Oncology, Cancer Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China. pxx2013@sohu.com.
authors.forename: Xingchen
authors.initials: X
authors.lastname: Peng
authors.forename: Can
authors.initials: C
authors.lastname: Luo
authors.forename: Guobo
authors.initials: G
authors.lastname: Shen
authors.forename: Chengjian
authors.initials: C
authors.lastname: Zhao
authors.forename: Liqun
authors.initials: L
authors.lastname: Zou
authors.forename: Longhao
authors.initials: L
authors.lastname: Li
authors.forename: Yaxiong
authors.initials: Y
authors.lastname: Sang
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Zhao
authors.forename: Xia
authors.initials: X
authors.lastname: Zhao
mesh_terms: D000368:Aged; D000595:Amino Acid Sequence; D000818:Animals; D014408:Biomarkers, Tumor / Q000737:chemistry / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000201:enzymology* / Q000401:mortality / Q000556:secondary; D002401:Cathepsin B / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000201:enzymology* / Q000401:mortality / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008875:Middle Aged; D008969:Molecular Sequence Data; D009368:Neoplasm Transplantation; D011379:Prognosis; D016016:Proportional Hazards Models; D020543:Proteome / Q000378:metabolism; D012189:Retrospective Studies; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D047368:Tumor Burden
chemical_list: D014408:Biomarkers, Tumor; D020543:Proteome; C533912:CTSB protein, human; D002401:Cathepsin B