[Suppression of RASSF1A gene on human esophageal carcinoma cells: experiments in vitro and in vivo].
OBJECTIVE
To investigate the effect of Ras association domain family 1A (RASSF1A) gene, a new tumor suppressor gene (TSG), on tumorigenesis of human esophageal carcinoma cells.


METHODS
pcDNA3.1 (+)-RASSF1A, a plasmid containing RASSF1A gene, and the blank plasmid pcDNA3.1 (+) were transfected into human esophageal carcinoma cells of the line EC9706. The expression of RASSF 1A protein was examined by Western blotting. The changes of cell cycle of stably-transfected cells were determined by flow cytometry (FCM), and the cellular proliferation was analyzed by MTT assay. Fifteen nude mice were randomly divided into 3 groups to be inoculated subcutaneously with EC9706 cells transfected with pcDNA3.1 (+)-RASSF1A, EC9706 cells transfected with pcDNA3.1 (+), and untransfected EC9706 cells respectively. Other 5 nude mice were used as controls. Four weeks later, the mice were killed to take out the carcinoma tissues. FCM was used to analyze the cell cycle.


RESULTS
Western blotting showed that RASSF1A protein was expressed highly in the stably transfected cells. The cell viability and growing speed were decreased obviously in the cells expressing of RASSF1A (both P < 0.01); FCM showed that the proportion of cells at the G(1) phase of the EC9706 cells expressing RASSF1A was significantly higher than those in the blank plasmid group and untransfected group (both P < 0.01). The size of the EC9706 cells obtained from the nude mice inoculated with the EC9706 cells transfected with pcDNA3.1 (+)-RASSF1A was significantly smaller than those of the pcDNA3.1 (+) group and blank plasmid group (both P < 0.05).


CONCLUSIONS
Expression of exogenous RASSF1A inhibits the progression of human esophageal carcinoma cells in vitro and in vivo. As a tumor suppressor gene, it plays an important role in origination, progression and metastasis of esophageal carcinoma.
Zhang
Tie-wa
TW
Harbin Medical University, Harbin 150081, China.
Wang
Sheng-fa
SF
Cong
De-gang
DG
Fu
Song-bin
SB
Meng
Xiang-ning
XN
Yu
Liang
L
Wang
Ju
J
D000818:Animals; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D004938:Esophageal Neoplasms / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010957:Plasmids / Q000235:genetics; D014162:Transfection; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000502:physiology; D023041:Xenograft Model Antitumor Assays
C411762:RASSF1 protein, human; D025521:Tumor Suppressor Proteins