CXCR1/CXCL8在结肠癌归巢性肝转移中作用的研究

Research on the Effect of CXCR1/CXCL8 in the Homing Metastases of Colorectal Cancer on Liver

目的探讨结肠癌发生器官特异性转移的规律性,研究CXCR1/CXCL8在转移性结肠癌瘤细胞归巢性肝转移中的作用。方法应用流式细胞术分析不同转移潜能结肠癌瘤细胞株、结肠癌原发灶及肝转移灶、正常结肠黏膜和肝组织中CXCR1的表达及其差别;分析CXCR1/CXCL8对肝转移性结肠癌瘤细胞CXCR1表达、瘤细胞生长、增殖性、侵袭能力、细胞骨架及定向运动能力的影响。结果Lovo、colon205胞膜CXCR1表达率分别为3.15%、6.67%;Lovo、co-lon205细胞经CXCL8刺激48h,CXCR1受体表达率50.45%和4.93%;Lovo细胞经CXCL8(75ng/ml)刺激前、后,CX-CR1表达量(ct值)为20.83和19.23;正常结肠黏膜、高分化结肠腺癌、低分化结肠腺癌中CXCR1的表达率分别为2.21%、6.65%和5.19%;正常肝组织、肝转移灶CXCR1的表达率为2.73%和22.62%;CXCL8刺激前、后Lovo细胞的增殖能力分别为3.27%和24.17%;CXCL8刺激后,Lovo细胞F-actin表现出解聚-聚合状态的改变,聚合程度呈时间性递增,高聚合状态表现在刺激后的72h;CXCR1/CXCL8作用前、后的lovo细胞侵袭数分别为74.2±13.28和6.39±1.8(P<0.01),趋化运动细胞数分别为89.67±6.16和18.53±5.59(P<0.05)。结论结肠癌瘤细胞CXCR1的表达与原发灶分化程度无关;CXCL8提高肝转移性结肠癌瘤细胞CXCR1的表达,“诱导”循环瘤细胞转变为肝转移性瘤细胞;CX-CL8/CXCR1介导肝转移瘤细胞的器官特异性转移过程,使结肠癌肝转移表现出与淋巴细胞趋化性迁移相类似的归巢性转移特征。在归巢性转移过程中,CXCL8/CXCR1具有器官特异性转移谱系特征,诱导转移瘤细胞的定向运动和转移灶形成。

Objective To explore the regularity of the organ-specific metastases on the metastatic colon cancer and to determine the chemotactic character of poor differentiated colon cancer with the liver metastasis. Methods The expression of chemokin receptor CXCR1 in human colon cancer cell line with different metastatic potentials were examined using Flow cytometric analysis, and the same comparison were also conducted in the primary colon cancer with distinct differentiation, the liver metastatic focus, the normal colon tissue and normal liver tissue. The effect of CXCR1/CXCL8 on the expression of CXCR1, cell growth and proliferation, the capability of invasive and directional migration, and re-regulation of cell cytoskeleton were analyzed respectively with real-time quantitative, MTT, modified Boyden chamber,and confocal microscopy. Results CXCR1 expression was low in lovo cell but elevated after the stimulation of different content of the correspondingCXCL8. While these effects were limited to the lovo cell, the low level of CXCR1 in colon205, SW620, HCT-8 was not responding to the biological effects of IL-8. In the sample of tissues, including the normal colon mucus and liver tissue, the primary focus of high differentiated colon cancer and livermetasatic colon cancer, the expression of receptor was low and no statistic significance with each other （P 〉 0.05 ）, while the result in the liver-metastatic focus was obviously rise, significantly different from other tissues （P 〈 0.05 ）. The invasive and migration cell numbers of lovo cell line was significantly different in the presence of CXCL8 or not and the former was higher than the later （P 〈 0.05 ）. It is observed that signaling through the interaction of CXCR1/CXCL8 mediates actin polymerization and pseudopodia formation,and subsequently induces chemotactic and invasive responses. Conclusion The expression of CXCR1 is low and homogenenous in different kinds of colon cancer cells. While in the existence of CXCL8 ,the low expression of CXCR1 in lovo cell is changed into higher level situation and has the characteristics of liver metastatic colon cancer cells in cell growth ,proliferation and directional migration. The expression of CXCR1 in liver metastatic focus is high and has the same modal in vivo. It is concluded that the interaction of CXCR1/CXCL8 is related to the organ-specific metastases on the metastatic colon cancer. The process of homing liver metastases on colon cancer is share with the chemotactic migration of lymphocyte.