RKIP在胃癌组织中的低表达及对其侵袭力的影响

Low expression of RKIP in gastric cancer and its role in gastric cancer cell migration

目的:检测Raf激酶抑制蛋白(Raf kinase inhibitory protein,RKIP)在胃癌(gastric cancer,GC)中的表达,分析其与GC生物学行为的关系,并探讨RKIP对GC侵袭能力的影响.方法:应用RT-PCR方法检测74例GC组织及其相应癌旁正常组织中RKIP mRNA的表达,并分析胃癌组织中RKIP mRNA的表达与各临床病理学特点之间的关系;Western blot检测GC组织及其癌旁正常组织中RKIP蛋白的表达变化.采用脂质体转染方法将正义、反义R K I P表达质粒及其相应空白载体分别转染SGC-7901细胞,建立相应的稳定转染细胞系,并用Western blot检测转染效果.应用Transwell细胞迁移实验研究分析RKIP表达水平改变对GC细胞体外侵袭能力的影响.结果:RT-PCR结果显示,RKIP mRNA在GC组织中的表达量相对值明显低于在癌旁组织中的表达相对值(0.12±0.02 vs 0.48±0.04,t=6.562,P<0.01).在GC组织中,RKIP mRNA的表达与肿瘤的分化程度、TNM分期、淋巴结转移有关(均P<0.05).RKIP蛋白在GC组织中表达明显低于癌旁正常组织(0.08±0.02vs 0.41±0.04,t=7.068,P<0.01).Transwell细胞迁移实验显示,上调RKIP表达能抑制SGC-7901细胞的侵袭能力,而下调RKIP表达能增强SGC-7901细胞的侵袭能力.结论:RKIP的低表达与胃癌的恶性程度及侵袭性关系密切,揭示RKIP可能是一个潜在预防胃癌转移的治疗靶点.

AIM： To detect the expression of Raf kinase in- hibitory protein （RKIP） in gastric cancer （GC）, to analyze the relationship between RKIP expres- sion and clinicopathological characteristics of GC, and to explore the role of RKIP in invasion of GC cells. METHODS： The expression levels of RKIP mRNA in 74 gastric cancer tissues and the cor- responding tumor-adjacent gastric tissues were detected by reverse transcription-polymerase chain reaction （RT-PCR）. The relationship between RKIP mRNA expression and clinico- pathological characteristics of GC was analyzed. Western blot was used to detect the expression level of RKIP protein. In addition, SGC-7901 cells were stably transfected with plasmids thatexpressed either sense or antisense RKIP cDNA, with the cells transfected with the empty plas- mid as a negative control. The effect of transfec- tion was detected by Western blot. Cell adhesion and invasion assays were used to analyze the ef- fect of RKIP expression on cell invasion in vitro. RESULTS： The expression level of RKIP mRNA in GC tissues was significantly lower titan that in adjacent gastric tissues （0.12 ± 0.02 vs 0.48±0.04, t = 6.562, P 〈 0.01）. The expression of RKIP mRNA was significantly associated with his- tologic differentiation, TNM stage, and lymph node metastasis （all P 〈 0.05）. RKIP protein ex- pression in cancer tissues was significantly low- er than that in adjacent gastric tissues （0.08 ±0.02 vs 0.41 ± 0.04, t = 7.068, P 〈 0.01）. Up-regulated RKIP in SGC-7901 cells could decrease cell inva- sion, whereas down-regulated RKIP increased cell invasion. CONCLUSION： Low expression of RKIP in gas- tric carcinoma is closely related to tumor malig- nancy and invasiveness, suggesting that RKIP may be a potential therapeutic target for the pre- vention of metastasis in GC patients.