Overexpression of stefin A in human esophageal squamous cell carcinoma cells inhibits tumor cell growth, angiogenesis, invasion, and metastasis.
OBJECTIVE
Evidence is accumulating that an inverse correlation exists between stefin A level and malignant progression. The aim of this study is to investigate the role of stefin A in human esophageal squamous cell carcinoma cells and to evaluate the possibility of stefin A for cancer therapy.


METHODS
We stably transfected stefin A cDNA into human EC9706 or KYSE150 esophageal squamous cell carcinoma cells. Subsequently, we evaluated the effect of stefin A overexpression on cell growth, cathepsin B activity, cell motility and invasion, tumor growth, and metastasis. Immunoanalysis was done to assess the expression of factor VIII and to support the localization of stefin A and cathepsin B. We also evaluated the effect of CA074Me, a selective membrane-permeant cathepsin B inhibitor.


RESULTS
Both transfection of stefin A and treatment with 10 micromol/L CA074Me significantly reduced cathepsin B activity and inhibited the Matrigel invasion. Combination of both further reduced cathepsin B activity and inhibited the Matrigel invasion. Overexpression of stefin A delayed the in vitro and in vivo growth of cells and significantly inhibited lung metastasis compared with 50% of lung metastasis in xenograft mice from EC9706 or empty vector cells. Transfection with stefin A showed a dramatic reduction of factor VIII staining in the tumors of xenograft mice.


CONCLUSIONS
Our data strongly indicate that stefin A plays an important role in the growth, angiogenesis, invasion, and metastasis of human esophageal squamous cell carcinoma cells and suggest that stefin A may be useful in cancer therapy.
Li
Wendong
W
National Laboratory of Molecular Oncology, Cancer Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P.R. China.
Ding
Fang
F
Zhang
Liyong
L
Liu
Zhongmin
Z
Wu
Yu
Y
Luo
Aiping
A
Wu
Min
M
Wang
Mingrong
M
Zhan
Qimin
Q
Liu
Zhihua
Z
D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000737:chemistry / Q000556:secondary / Q000628:therapy*; D002401:Cathepsin B / Q000032:analysis / Q000037:antagonists & inhibitors*; D055312:Cystatin A; D015891:Cystatins / Q000032:analysis / Q000235:genetics*; D004938:Esophageal Neoplasms / Q000737:chemistry / Q000473:pathology / Q000628:therapy*; D015316:Genetic Therapy; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009361:Neoplasm Invasiveness / Q000517:prevention & control; D009362:Neoplasm Metastasis / Q000517:prevention & control; D009389:Neovascularization, Pathologic / Q000517:prevention & control*; D015533:Transcriptional Activation; D014162:Transfection
D055312:Cystatin A; D015891:Cystatins; D002401:Cathepsin B