核基质蛋白LaminA/C在正常乳腺和乳腺癌组织中的差异表达

The Differential Expression of LaminA/C in Normal Human Breast Tissue and in Breast Carcinoma Tissue

目的:采用比较蛋白质组学方法研究正常乳腺和乳腺癌组织中的差异表达核基质蛋白(nuclear matrix protein,NMP),并在蛋白质水平对差异蛋白LaminA/C进一步地确证。方法:分别提取4例正常乳腺和乳腺癌组织的核基质蛋白,进行双向凝胶电泳。分离出的差异表达蛋白质点进行基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)分析,获得肽质量指纹图谱(Peptide Mass Fingerprinting,PMF),应用Mascot搜索引擎在NCBInr数据库中进行检索鉴定。最后用免疫组化和Western blotting方法验证差异蛋白LaminA/C在正常乳腺和乳腺癌组织的相对表达量。结果:经双向凝胶电泳和质谱鉴定,正常乳腺组含有(904±58)个蛋白质点,乳腺癌组检测出含有(944±70)个蛋白质点,共发现27个差异表达蛋白,成功鉴定出12种蛋白,其中包括LaminA/C。用免疫组化方法分析LaminA/C在正常乳腺和乳腺癌组织各20例中的表达,结果显示LaminA/C在正常乳腺和乳腺癌组织中的阳性率分别为15%(3/20)和40%(8/20),P<0.05。用Western blot方法观察LaminA/C在正常乳腺和乳腺癌组织各10例中的表达,结果显示乳腺癌组中LaminA/C/β-actin灰度值比值为0.40±0.13,是正常乳腺组LaminA/C/β-actin灰度值比值(0.21±0.13)的1.91倍(P<0.05)。结论:LaminA/C在乳腺癌组织中表达明显增高,LaminA/C蛋白在乳腺癌的发生和发展中可能起一定的作用。

Objective： To study the differential expression of nuclear matrix proteins （NMPs） in normal human breast tissue and in breast carcinoma tissue using comparative proteornic methods and to further confirm the up-regulation of LaminNC. Methods： NMPs were extracted from 4 normal human breast tissue samples and 4 breast carcinoma tissue samples. Then NMPs were separated by immobilized pH gradient-based two-dimensional polyacrylamide gel electrophoresis （2-DE）. Differentially expressed proteins in the protein profiling were analyzed with Image Master software and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF-MS）. A list of the corrected mass peaks was obtained as Peptide Mass Fingerprinting （PMF）. The different NMPs were analyzed in the National Center for Biotechnology Information （NCBI） database with Mascot search engine. Differential expression of LaminNC was assayed by Immunohistochemistry （IHC） and Western blot. Results： Well-resolved, reproducible 2-DE profiles of human breast tissue were obtained. Average protein spots were 904±58 in normal human breast tissue and 944±70 in breast carcinoma tissue. Of the 27 spots analyzed, 12 proteins including LaminA/C were successfully identified. The positive rates of LaminA/C in the normal breast tissue samples and in breast carcinoma tissue were （15%, 3/20） and （40%, 8/20）, respectively, with a statisitical significance （P〈0.05）. Western blot analysis showed positive expression of LaminA/C in 10 normal breast tissue statistical samples and 10 breast carcinoma tissue samples and the ratio of LaminNC/β-actin was 0.21 ±0.13 and 0.40±0.13, respectively. The mean intensity of LaminNC showed a significant difference between normal breast tissue and breast carcinoma tissue （P〈0.05）. Conclusion： Higher expression of LaminA/C was found in breast cancer tissue. LaminA/C may be useful for distinguishing normal breast tissue from tumor tissue and may play a role in the pathogenesis of breast carcinoma.