Molecular Characterization of the Tumor-Suppressive Function of Nischarin in Breast Cancer
Molecular Characterization of the Tumor-Suppressive Function of Nischarin in Breast Cancer
复制标题
DOI：
10.1093/jnci/djr350
复制
发表时间：
2011-10-01
期刊：
影响因子：
--
通讯作者：
Alahari, Suresh K.
中科院分区：
文献类型：
--
作者：
Baranwal, Somesh;Wang, Yanfang;Alahari, Suresh K.
背景Nischarin（由NISCH编码）是一种α 5整合素结合蛋白，已被鉴定为乳腺癌细胞侵袭的调节因子。我们假设，它可能是一个肿瘤抑制因子，并有兴趣在其regulation.Methods我们研究了nischarin表达在约300人乳腺癌和正常组织，采用定量聚合酶链反应和免疫组化。通过检测位于正常和肿瘤组织中NISCH位点附近的三个微卫星标记进行杂合性缺失分析。我们产生过表达nischarin的MDA-MB-231人转移性乳腺癌细胞的衍生物，并测量这些细胞作为小鼠异种移植物的肿瘤生长;尾静脉注射后这些细胞的转移;以及使用蛋白质印迹法测量α 5整联蛋白表达、Rac和粘着斑激酶（FAK）信号传导。我们还产生了MCF-7人乳腺癌细胞的克隆，其中nischarin表达被沉默，并测量了小鼠异种移植模型中的肿瘤生长（对于所有小鼠实验，n = 5）。结果正常人乳腺组织中Nischarin mRNA的表达水平显著高于肿瘤组织（正常乳腺中的平均水平= 50.7 [任意单位]，乳腺肿瘤中的平均水平= 16.49 [任意单位]，差异= 34.21，95%可信区间[CI] = 11.63至56.79，P = 0.003），杂合性缺失与Nischarin表达缺失相关。与亲本MDA-MB-231细胞相比，其中Nischarin过表达的MDA-MB-231细胞具有统计学显著降低的肿瘤生长和转移（第40天的平均体积，对照与Nischarin表达肿瘤，1977与42.27 mm（3），差异= 1935 mm（3），95%CI = 395至3475 mm（3），P = 0.025）。此外，其中nischarin表达被沉默的MCF-7肿瘤异种移植物的生长在统计学上显著快于亲本细胞（第63天的平均体积，具有乱序短发夹RNA [shRNA]的肿瘤与具有nischarin shRNA的肿瘤，224与1262 mm（3），差异= 1038 mm（3），95%CI = 899.6至1176 mm（3），P <0.001）。Nischarin的过表达与α 5整合素表达降低、FAK磷酸化和Rac activation.Conclusion Nischarin可能是一种新的肿瘤抑制因子，通过调节α 5整合素表达，进而调节α 5整合素、FAK和Rac介导的信号传导，限制乳腺癌的进展。J Natl Cancer Inst 2011; 103：1513-1528
Background Nischarin (encoded by NISCH), an alpha 5 integrin-binding protein, has been identified as a regulator of breast cancer cell invasion. We hypothesized that it might be a tumor suppressor and were interested in its regulation.Methods We examined nischarin expression in approximately 300 human breast cancer and normal tissues using quantitative polymerase chain reaction and immunohistochemistry. Loss of heterozygosity analysis was performed by examining three microsatellite markers located near the NISCH locus in normal and tumor tissues. We generated derivatives of MDA-MB-231 human metastatic breast cancer cells that overexpressed nischarin and measured tumor growth from these cells as xenografts in mice; metastasis by these cells after tail vein injection; and a5 integrin expression, Rac, and focal adhesion kinase (FAK) signaling using western blotting. We also generated clones of MCF-7 human breast cancer cells in which nischarin expression was silenced and measured tumor growth in mouse xenograft models (n = 5 for all mouse experiments). P values were from two-sided Student t tests in pairwise comparisons.Results Normal human breast tissue samples had statistically significantly higher expression of nischarin mRNA compared with tumor tissue samples (mean level in normal breast = 50.7 [arbitrary units], in breast tumor = 16.49 [arbitrary units], difference = 34.21, 95% confidence interval [CI] = 11.63 to 56.79, P = .003), and loss of heterozygosity was associated with loss of nischarin expression. MDA-MB-231 cells in which nischarin was overexpressed had statistically significantly reduced tumor growth and metastasis compared with parental MDA-MB-231 cells (mean volume at day 40, control vs nischarin-expressing tumors, 1977 vs 42.27 mm(3), difference = 1935 mm(3), 95% CI = 395 to 3475 mm(3), P = .025). Moreover, MCF-7 tumor xenografts in which nischarin expression was silenced grew statistically significantly faster than parental cells (mean volume at day 63, tumors with scrambled short hairpin RNA [shRNA] vs with nischarin shRNA, 224 vs 1262 mm(3), difference = 1038 mm(3), 95% CI = 899.6 to 1176 mm(3), P < .001). Overexpression of nischarin was associated with decreased alpha 5 integrin expression, FAK phosphorylation, and Rac activation.Conclusion Nischarin may be a novel tumor suppressor that limits breast cancer progression by regulating alpha 5 integrin expression and subsequently a5 integrin-, FAK-, and Rac-mediated signaling. J Natl Cancer Inst 2011; 103: 1513-1528