Authors: Kejun Zhang Shaoyan Zhang Xuelong Jiao Haibo Wang Dianliang Zhang Zhaojian Niu Yi Shen Liang Lv Yanbing Zhou
Publish Date: 2010/08/21
Volume: 28, Issue: 4, Pages: 1089-1100
Abstract
Slug is a transcription factor and Ecadherin repressor which has recently been demonstrated to be important for cancer cells to downregulate epithelial markers and upregulate mesenchymal markers in order to become motile and invasive In the present study we assessed the relevance of Slug for invasion and growth potential of esophageal adenocarcinoma EA cells in vitro and in vivo Slug expression was detected in nine human esophageal cancer cell lines OE33 cell line was infected with Slug siRNA to knockdown of Slug TE7 cell line was infected with full Slug cDNA to increase Slug expression Then Bcl2 and Ecadherin expression and Caspase3 activity were analyzed MTT assay was applied to detect growth curve The flow cytometric and Hoechst33258 staining was performed to detect apoptosis The cells invasion in vitro was detected with a Boyden chamber A pseudometastatic model of OE33 and TE7 in immunodeficient mice was used to assess the effects of knockdown of Slug and Slug overexpression on metastasis development A subcutaneously nude mice xenograft model of OE33 and TE7 was used to assess the effects of knockdown of Slug and Slug overexpression on tumor growth Immunohistochemical staining was used to analyze the expression of Slug bcl2 and Ecadherin and TUNEL was used to detected apoptosis in vivo Western blotting and RTPCR showed that Slug expression was detectable in 7 of 9 human esophageal cancer cell lines Bcl2 was downregulated and Ecadherin was upregulated significantly in Slug siRNAinfected OE33 cell line P 001 Bcl2 was upregulated and Ecadherin was downregulated significantly in Slug cDNAinfected TE7 cells P 005 OE33 cells with Slug knockdown were shown to possess markedly decreased invasiveness P 005 and markedly increased apoptosis P 005 Slug cDNAinfected TE7 cells were shown only to possess markedly increased invasiveness P 005 There was significant relationship between Slug knockdown or Slug overexpression and cells proliferation respectively P 005 Animals injected with Slugsilenced OE33 cells had fewer seeded tumor P 001 more apoptosis cells P 005 and significantly xenograft tumor growth regression P 005 But in Slug cDNAinfected TE7 cells more seeded tumor number and significantly xenograft tumor growth were found in xenograft tumor respectively P 005 It was showed in the subcutaneously nude mice xenograft model tumor tissue bcl2 expression was reduced followed by the decrease of Slug expression in Slugsilenced tumor and bcl2 expression was increased followed by the increase of Slug expression In pseudometastatic model Ecadherin overexpression was found in Slug siRNA tumor tissue but less Ecadherin expression was found in Slug cDNA tissue Slug is an important modulator of apoptosis growth and invasion in EA in vitro and in vivo Slug inhibition may represent a novel strategy for treatment of EA
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