葡萄糖调节蛋白78kD和热休克蛋白20在左半及右半结肠癌差异表达的初步研究

Preliminary study on glucose regulated protein 78 kD and heat shock protein 20 differential expression between left-sided colon carcinoma and right-sided colon carcinoma

目的分析左半结肠癌与右半结肠癌肿瘤组织中差异蛋白表达情况。方法收集人左半结肠癌和右半结肠癌组织标本各7例．提取组织蛋白并进行二维凝胶电泳、质谱分析及生物信息学分离．鉴定二者中差异表达蛋白质。应用免疫组织化学sP法检测葡萄糖调节蛋白78kD（GRP78）和热休克蛋白20（HSP20）在50例左半和50例右半结肠癌组织中的表达情况。结果筛选并成功鉴定出左半和右半结肠癌中16种差异表达蛋白质：与右半结肠癌比较，左半结肠癌10种蛋白表达上调，6种蛋白表达下调，其中GRP78在左半结肠癌中表达上调，HSP20在左半结肠癌中表达下调。免疫组织化学检测示．GRP78在左半和右半结肠癌组织的阳性表达率分别为78％（39／50）和56％（28／50），差异有统计学意义（P〈0．05）；HSP20在左半和右半结肠癌的阳性表达率分别为34％（17／50）和72％（36／50），差异亦有统计学意义（P〈0．05）。GRP78表达与肿瘤分化程度、浸润层次、TNM分期、有无淋巴结转移以及有无肝转移有关（P〈0．05），而HSP20的表达与肿瘤大体形态、TNM分期以及有无淋巴结转移有关（P〈0．05）。结论左半结肠癌和右半结肠癌的蛋白质组存在蒡异．这些可能是左半与右半结肠癌生物学行为存在差异的原因。

Objective To analyze the differential protein expression of left-sided colon cancer and right-sided colon cancer. Methods Tissue samples of left-sided colon cancer（n=7） and right-sided colon cancer（n=7） were collected. Tissue protein was abstracted and two-dimensional gel electrophoresis （2-DE） was used to examine the gel images. Peptide mass fingerprintings （PMF） was acquired by matrix assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF-MS） and the proteins were identified by data searching with bioinformaties. Immunohistochemical SP method was used for the detection of glucose regulated protein 78 kD （GRP78） and heat shock protein 20 （HSP20） in left-sided colon cancer （n=50） and right-sided colon cancer （n=50） tissues. Results Sixteen differentiating protein spots were identified. Compared with right-sided colon cancer, 10 proteins including GRP78 up-regulated and 6 proteins including HSP20 down-regulated in left-sided colon cancer. Immunohistochemical detection showed that in left and right sided colon cancer, the positive expression rate of GRP78 was 78%（39/50） and 56%（28/50） and the positive expression rate of HSP20 was 34%（17/50） and 72%（36/50）, respectively, and the differences were statistically significant（both P〈0.05）. The positive rate of GRP78 was associated with tumor differentiation, infiltration layer, TNM staging, lymph node metastasis, and liver metastasis, while the positive rate of HSP20 was associated with tumor gross morphology, TNM staging, and lymph node metastasis （P〈0.05）. Conclusions There are differentially expressed proteins between left-sided colon cancer and right-sided colon cancer, especially for GRP78 and HSP20, which may be the cause leading to the biological differences between left-sided and right-sided colon cancer.