Activated signal transducer and activator of transcription 3 (STAT3) supports the malignant phenotype of human pancreatic cancer
Activated signal transducer and activator of transcription 3 (STAT3) supports the malignant phenotype of human pancreatic cancer
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DOI：
10.1016/s0016-5085(03)01064-3
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发表时间：
2003-09-01
期刊：
影响因子：
29.4
通讯作者：
Rosewicz, S
中科院分区：
文献类型：
--
作者：
Scholz, A;Heinze, S;Rosewicz, S
背景与目的：信号转导和转录激活因子3(STAT3)的结构性激活参与了细胞生长和恶性转化的调控。因此，我们分析了STAT3在人胰腺癌细胞中的表达及其生物学意义。方法：采用免疫组织化学和免疫印迹法检测STAT3的表达和激活情况。通过在2个胰腺癌细胞系中稳定地转导显性-负性STAT3结构，实现了STAT3的功能失活，并通过凝胶迁移率改变分析和免疫印迹证实了这一点。通过细胞计数、软琼脂集落形成和裸鼠异种移植评价细胞增殖和致瘤性。用流式细胞术、免疫沉淀、免疫印迹、组蛋白H1和GST-Rb激酶检测STAT3依赖的细胞周期分布。结果：与未转化的人胰腺相比，活化的STAT3在导管癌细胞中高表达，而在慢性胰腺炎的导管中不表达，在所有被检测的人胰腺癌细胞系中也观察到了结构性激活。在体外，STAT3功能失活可显著抑制锚定依赖性和非依赖性增殖，并抑制体内肿瘤生长。细胞周期分析显示，由于p21(Waf1)在体内外的表达增加，细胞周期蛋白依赖的激酶2活性受到抑制，细胞周期延迟了G(1)/S期的进程。酪氨酸蛋白阻断STAT3上游激活子Janus kinase2也可导致细胞生长停滞，原因是细胞周期G(1)/S期延迟，p21(Waf1)表达增加。结论：在恶性转化过程中，活化的STAT3通过加速细胞的G(1)/S期进程而促进细胞增殖，从而促进胰腺癌的恶性表型。
Background & Aims: Constitutive activation of signal transducer and activator of transcription 3 (STAT3) has been implicated in regulation of growth and malignant transformation. We therefore analyzed the expression and biologic significance of STAT3 in human pancreatic cancer cells. Methods: Expression and activation of STAT3 were investigated by immunohistochemistry and immunoblotting. Functional inactivation of STAT3 was achieved by stable transfection of dominant-negative STAT3 constructs in 2 pancreatic cancer cell lines and confirmed by electrophoretic mobility shift assay and immunoblotting. Cell proliferation and tumorigenicity were evaluated by cell counting, colony formation in soft agar, and xenotransplantation in nude mice. STAT3-dependent cell cycle distribution was monitored by flow cytometry, immunoprecipitation, immunoblotting, and histone H1 and GST-Rb kinase assays. Results: Compared with nontransformed human pancreas, activated STAT3 is overexpressed in ductal carcinoma cells but not in ducts from chronic pancreatitis, Constitutive activation was also observed in all human pancreatic cancer cell lines examined. Functional inactivation of STAT3 resulted in significant inhibition of anchorage-dependent and -independent proliferation in vitro and reduced tumor growth in vivo. Cell cycle analysis showed a delay of G(1)/S-phase progression due to inhibition of cyclin-dependent kinase 2 activity based on increased expression of p21(WAF1) in vitro and in vivo. Blocking of the STAT3 upstream activator Janus kinase 2 by tyrphostin also resulted in growth arrest because of delayed G(1)/S-phase progression and increased expression of p21(WAF1). Conclusions: On malignant transformation, activated STAT3 promotes cellular proliferation by acceleration of G(1)/S-phase progression and thereby contributes to the malignant phenotype of human pancreatic cancer.