Analysis of structure of MRP-1/CD9 mutation and regulation of metastasis of cancer by means of MRP-1/CD9 control

我们以前的研究表明，运动相关蛋白-1(MRP-1)是一种被单抗M31-15识别的糖蛋白，其序列与白细胞分化抗原CD9的序列完全相同。将MRP-1/CD9基因导入培养的非造血细胞可抑制细胞运动。抑制的程度与MRP-1/CD9的表达水平直接相关。此外，转导MRP-1/CD9的黑色素瘤细胞BL6的转移潜能低于对照组BL6。为了确定这些实验结果是否与实际人类肿瘤相关，我们研究了143例乳腺浸润性导管癌中MRP-1/CD9的表达。在97例MRP-1/CD9阳性的肿瘤中，仅36例(37.1%)有淋巴结转移。相比之下，mrp-1/cd9免疫反应减弱的患者21/39例(53.8%)，原发癌抗mrp-1/cd9单抗未染色的5/7例患者有lym…。更多的ph结转移者。比较62例原发肿瘤及其相应转移淋巴结的蛋白表达，发现近50%的转移淋巴结中MRP-1/CD9水平低于前者。此外，逆转录聚合酶链式反应(RT-PCR)分析显示，17/32例浸润性导管癌转移淋巴结中MRP-1/CD9基因的表达明显低于原发浸润性导管癌。在所研究的任何样本中都没有观察到基因过度表达。我们的数据提示，MRP-1/CD9的低表达可能与某些人类肿瘤的转移潜能有关。考虑到这些发现，我们现在应用RT-PCR来检测MRP-1/CD9基因在肺癌中的表达。我们分析了109例患者的肿瘤组织，其中49例为I期，15例为II期，45例为III期。我们发现67例患者存在MRP-1/CD9阳性肿瘤，其余42例肿瘤中基因表达下调。肿瘤阳性患者的总体存活率显著高于基因表达降低的患者(62.3%vs.34.9%；p&lt；0.001)。这也与肺腺癌患者有关(55.4%vs.26.0%；p&lt；0.001)。COX回归模型多因素分析显示，除淋巴结状况外，MRP-1/CD9阳性与总生存率的相关性优于其他变量。我们的数据提示，肺肿瘤MRP-1/CD9的低表达可能与预后不良有关。可以想象，MRP-1/CD9检测可以确定淋巴结阴性的肺癌患者和腺癌患者，他们是早期疾病复发的高危人群。另一方面，对肺癌的序列分析表明，MRP-1/CD9在第143密码子和163密码子上有热点，这两个密码子都是从A到G的变化，前者的氨基酸从Lys到ARG，后者从ASN到ASP。较少

In our previous studies we showed that motility related protein-1 (MRP-1) is a glycoprotein recognized by monoclonal antibody (MAb) M31-15, and that the sequence of MRP-1 is identical to that of CD9, a white cell differentiation antigen. Transfection of MRP-1/CD9 cDNA into cultured non-hematopoietic cells suppresses cell motility. The extent of suppression is directly related to the level of MRP-1/CD9 expression. In addition, the metastatic potential of MRP-1/CD9-transfected melanoma cells BL6 is lower than that of control BL6 cells. To determine whether these experimental results are of relevance with respect to actual human tumors, we investigated MRP-1/CD9 expression in 143 invasive ductal carcinomas of the breast. Of 97 patients with MRP-1/CD9-positive tumors, only 36 (37.1%) had lymph node involvement. By contrast, 21/39 (53.8%) patients whose tumors had reduced MRP-1/CD9 immunoreactivity, and 5/7 patients whose primary carcinomas were not stained by the anti-MRP-1/CD9 MAb had lym … More ph node metastases. The comparison of protein expression by 62 primary tumors and their respective metastatic lymph nodes revealed that in almost 50% of the cases the latter had lower MRP-1/CD9 levels than the former. Moreover, reverse transcriptase polymerase chain reaction (RT-PCR)-based analysis disclosed that MRP-1/CD9 gene expression in the metastatic lymph nodes of 17/32 patients was strikingly lower than in the primary invasive ductal carcinomas. Gene overexpression was not observed in any of the samples studied. Our data suggest that low MRP-1/CD9 expression may be associated with the metastatic potential of certain human tumors. In consideration of these findings, we have now applied RT-PCR to determine MRP-1/CD9 gene expression in lung cancer. We analyzed tumor tissues of 109 patients ; 49 tumors were stage I,15, stage II and 45, stage III.We found that 67 patients had MRP-1/CD9 -positive tumors, and that gene expression was reduced in the tumors of the remaining 42 individuals. The overall rate of survival was strikingly higher among patients with positive tumors than in those whose tumors had reduced gene expression (62.3% vs.34.9% ; p<0.001). This also pertained to patients with adenocarcinomas of the lung (55.4% vs.26.0% ; p<0.001). Multivariate analysis with the Cox regression model indicated that MRP-1/CD9 positivity correlated better with overall survival rate than other variables, except lymph node status. Our data suggest that low MRP-1/CD9 expression by tumors of the lung may be associated with poor prognosis. It is conceivable that testing for MRP-1/CD9 may identify node-negative lung cancer patients and patients with adenocarcinomas who are at high risk for early disease recurrence. On the other hand, sequence analysis with lung cancer revealed that MRP-1/CD9 have the hot spots at codon 143 and 163, both of which change from A to G.The former aminoacid changes are from LYS to ARG,and the latter from ASN to ASP. Less