原位杂交检测新免疫球蛋白基因SNC73在大肠癌中的表达

目的:确定新免疫球蛋白基因SNC73在大肠癌中的组织学定位;观察它在大肠癌发生、发展不同阶段的表达状况;探讨其表达与大肠癌表型的相关性。方法:用地高辛标记的原位杂交技术检测SNC73基因在29例大肠癌病人的正常肠粘膜、癌旁粘膜、腺瘤5例以及癌组织中的表达状况。结果:SNC73基因的表达发生在大肠的正常腺上皮结构上,着色颗粒位于胞浆,胞核无或着色较淡;癌组织中没有或有少量表达,且一般较正常粘膜染色为淡;SNC73基因在肠粘膜的淋巴滤泡中可见较多的阳性染色,而在其他间质和肌层中未见明显阳性信号。正常粘膜标本中SNC基因阳性率为62.07%;癌旁粘膜中31.03%;腺瘤中20.00%;癌组织中20.69%。SNC73基因在同一大肠癌病人正常粘膜和癌组织中表达之间存在显著性差异(P<0.01)在大肠癌组织中表达的阳性率明显低于正常肠粘膜。结论:SNC73基因在大肠癌中的表达率一定程度上低于相应的正常粘膜,其生物学功能可能不同于一般意义上的免疫球蛋白。

新基因SNC66和SNC73在大肠粘膜和大肠癌中表达的比较

目的 :研究新基因SNC 6 6和SNC 73的表达状况 ,并探讨其与大肠癌发生的相关性。方法 :采用体外转录的方法合成地高辛标记的探针 ,并用它进行cRNA/mRNA原位分子杂交 ,检测37例大肠癌标本及其相应正常大肠粘膜中SNC 6 6和SNC 73两基因表达mRNA的状况 ,并加以比较。结果 :SNC 6 6和SNC 73基因只在上皮细胞和淋巴细胞中表达 ,在大肠癌组织中都存在明显的表达缺陷 ,尤其以SNC 73的表达缺陷更明显。SNC 6 6在粘膜绒毛上多呈梯度性表达 ,以隐窝处最深 ,到绒毛顶端逐渐变淡 ;SNC 73则多呈均一性表达。结论 :SNC 6 6和SNC 73是表达行为、代谢途径均有所不同的两个免疫球蛋白样大肠癌负相关基因 。

Expression of SNC73, a transcript of the immunoglobulin α-1 gene, in human epithelial carcinomas

AIM： To investigate the expression of SNC73, a transcript of the immunoglobulin α-1 gene （IgA1-H chain）, in human epitheliα-derived tumor cells. METHODS： Total RNAs and cell lysates were prepared from five different human epithelial cell lines derived from lung, stomach, liver, skin, and breast, respectively. RT-PCR and immunoblot analysis of these five cell lines were done. Both RT-PCR and immunochemistry were used to detect the expression of SNC73 in these cell lines. We also examined the expression of SNC73 in normal epithelial cells of colon mucosa by in situ hybridization. RT-PCR and immunoblot analysis were used to determine whether the recombination activating gene1/2 （RAG1 and RAG2） is present. The expression of three immunoglobulin transcription factors, EBF, E2A and Pax5, and the heavy chain of IgA1 and two types of light chains of immunoglobulin （κ and λ） in the aforementioned cell lines were analyzed by RT-PCR and immunochemistry, respectively. All the RT-PCR products were analyzed by sequencing. RESULTS： The results of RT-PCR and immunochemistry showed that both mRNA and protein of SNC73 were expressed in five human epitheliα-derived cancer cell lines. These data were further confirmed in the normal epithelial cells of colon mucosa by in situ hybridization. Also, the heavy chain of IgA1 and κ light chain were detected in these cells, but no λ light chain was observed. Both RAG1 and RAG2 were expressed in these human epitheliα-derived cancer cell lines and the sequence was identical to that expressed in pre-B and pre-T cells. In addition to RAG1 and RAG2, the mRNA in one of the immunoglobulin transcription factors, EBF, was also detected in these cell lines, and Pax5 was only expressed in SW480 cells, but no expression of E2A was observed in all the five cell lines. CONCLUSION： Immunoglobulin A1 is originally expressed and V（D）J recombination machine is also present in non-lymphoid cells, suggesting that V（D）J recombination machine mediates the assembly of immunoglobulin A1 in non-lymphoid cells as in prelymphocytes.

Expression of a novel immunoglobulin gene SNC73 in human cancer and non-cancerous tissues

AIM: To investigate the expression of immunoglobulin gene SNC73 in malignant tumors and non-cancerous normal tissues.METHODS: Expression level of SNC73 in tumors and non-cancerous tissues from the same patient was determined by reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay (RT-PCR-ELISA) in 90 cases of malignant tumors, including colorectal cancer, gastric cancer, breast cancer, lung cancer and liver cancer, Analysis on the correlation of SNC73 expression with sex, age, site,grade of differentiation, depth of invasion, and metastases in colorectal cancer patients was made.RESULTS: Expression level of SNC73 in non-cancerous colorectal mucosa and colorectal cancerous tissues was 1.234±0.842 and 0.737±0.731, respectively (P<0.01), with the mean ratio of 7.134±14.092 (range, 0.36-59.54).Expression of SNC73 showed no significant difference among gastric cancer, breast cancer, lung cancer and liver cancer when compared with non-cancerous tissues (P>0.05). No correlation was found between SNC73 expression level and various clinicopathological factors, including sex, age, site,grade of differentiation, depth of invasion and metastases of CRC patients.CONCLUSION: Down-regulation of SNC73 expression may be a relatively specific phenomenon in colorectal cancer.SNC73 is a potential genetic marker for the carcinongenesis of colorectal cancer. The relationship of SNC73 expression and carcinogenesis of colorectal cancer merits further study.

大肠癌相关免疫球蛋白新基因SNC73结构与表达研究

目的 研究由减式杂交方法获得的人大肠癌相关基因SNC73的结构和功能。方法 对SNC73的cDNA进行了核苷酸序列测定 ,分析得到全长序列 ,并对其编码的蛋白进行了分析及预测 ;采用Insitu Max荧光原位杂交方法结合荧光R带技术对SNC73在人染色体上的定位作了研究 ;利用Northern杂交、逆转录聚合酶链反应 (RT PCR)方法检测了SNC73在多种肿瘤细胞系中的表达 ,及在大肠癌组织与正常粘膜中的表达情况 ;应用原位杂交 /原位PCR技术检测SNC73mRNA在肠上皮中的表达情况。结果 对SNC73序列及开放阅读框 (ORF)进行分析 ,发现其与免疫球蛋白IgA高度同源 ,为一免疫球蛋白样基因。该基因定位于人染色体 14q32。SNC73在大肠癌组织与正常肠粘膜的表达有差异 (P <0 .0 5 )。SNC73在肠上皮表达阳性。结论 SNC73在大肠癌中低表达 ,可能为一新的肿瘤标记物 ,并提示上皮细胞、非淋巴细胞存在IgA类的蛋白。

肿瘤组织中免疫球蛋白基因SNC73的表达及其临床意义

目的 探讨免疫球蛋白基因SNC73在不同恶性肿瘤组织及其自身对照正常组织中的表达及临床意义。方法 采用逆转录聚合酶链反应酶联免疫吸附 (RT PCR ELISA)法 ,检测SNC73基因在 90例恶性肿瘤 (大肠癌、胃癌、乳腺癌、肺癌、肝癌 )及其相对应的对照正常组织中的表达 ,并对SNC73表达与大肠癌患者的性别、年龄、发病部位、分化程度、侵袭深度和转移等临床病理特征的相关性进行分析。结果 SNC73基因在正常黏膜及大肠癌表达量的比值为 7.134 ,差异有显著性 (P <0 .0 1)。胃癌、乳腺癌、肺癌和肝癌组织的SNC73表达量与自身对照正常组织比较 ,差异无显著性(P >0 .0 5 )。结论 SNC73的表达下调是大肠癌相对特异的现象 ,提示其可能为大肠癌发生发展中新的肿瘤标记 ,其与大肠癌发生发展的相关性 ,值得进一步研究。

大肠癌相关新基因SNC73在人上皮肿瘤组织中的表达研究

目的 原位检测大肠癌相关新基因SNC73在常见上皮肿瘤中的表达状况 ,探讨该基因表达与上皮肿瘤发生的相互关系。方法 采用cRNA/mRNA原位杂交的方法 ,用体外转录制备的地高辛标记的cRNA探针对大肠癌、胃癌、肝癌、肺癌和乳腺癌组织及同一患者的相应正常组织作表达情况的配对研究。结果 SNC73基因在胃、大肠黏膜的上皮细胞及淋巴细胞呈强阳性表达 ,在其他组织细胞中未见表达 ;在大肠癌和胃癌组织中存在明显的表达降低或缺乏 ;在肝癌、肺癌和乳腺癌及其相应正常组织中都未见表达。结论 SNC73是一个IgA样消化道肿瘤相关基因 。

SNC73基因在结肠癌细胞中的表达及重组的研究

目的 观察上皮来源的肿瘤细胞SNC73(IgHα1)基因的表达 ,探讨其在上皮细胞中的重组机理。方法 采用逆转录聚合酶链反应 (RT PCR)和Western印迹杂交方法 ,分析经无血清培养基培养的大肠癌细胞系SW4 80中SNC73和重组激活基因 (RAG1和RAG2 )的表达 ,并对RT PCR产物进行序列分析 ;利用免疫组织化学方法检测IgHα1、Igλ和Igκ在SW 4 80中的表达。 结果 SNC73、RAG1、RAG2、IgHα1和Igκ在SW 4 80细胞系中表达阳性 ,而Igλ则为阴性。对SNC73RT PCR产物的序列进行分析 ,发现SW 4 80中表达的SNC73基因的恒定区序列与免疫球蛋白A1完全一致。对RAG1和RAG2RT PCR产物的序列进行分析以及Western印迹杂交检测 ,表明其与前B淋巴细胞表达的完全相同。结论 上皮来源的肿瘤细胞表达免疫球蛋白A1,且轻链为κ;RAG1和RAG2在上皮来源的肿瘤细胞中的表达 。