云南省大姚县青石棉污染区恶性胸膜间皮瘤与致瘤性猿猴病毒SV40的关联研究

Association between malignant pleural mesothelioma and oncogenic simian virus SV40 in crocidolite contaminated area of Dayao County,Yunnan Province

背景我国云南省楚雄彝族自治州大姚县5%地表散布蓝色青石棉,是恶性胸膜间皮瘤(malignant pleural mesothelioma,MPM)的高发区。致瘤性猿猴病毒SV40(simian virus 40,SV40)是一种小型环状双链DNA多瘤病毒,可使人和动物多种组织类型的正常细胞发生恶性转化并促进肿瘤生长。早年的流行病学调查显示,大姚县青石棉污染区恶性间皮瘤发病率高出一般人群几十倍,该地区MPM的发生是否与致瘤性SV40相关尚未见报道。目的本研究旨在探讨致瘤性猿猴病毒SV40是否与云南省大姚县青石棉污染区MPM的发生相关。方法收集大理大学第四附属医院(楚雄彝族自治州第一人民医院)和大姚县人民医院胸外科2014年1月-2019年12月诊治的51例(其中40例有石棉暴露史)MPM患者的肿瘤组织和12例非MPM患者的胸膜组织(包括肺大疱、肺结核等疾病)。同时,体外培养人正常胸膜间皮细胞LP9、Met5A(SV40转化的间皮细胞)和MPM细胞系NCI-H28(上皮型)、NCI-H2052(肉瘤型)、NCI-H2452(双相混合型)。提取各组细胞和组织基因组DNA后,用3组低污染风险引物(SVINT、SVfor2和SVTA1)对SV40大T抗原(TAg)的基因片段分别进行聚合酶链式反应(PCR)扩增检测,用两种SV40 TAg相关抗体(PAb101和PAb416)分别进行Western blotting和免疫组织化学染色,检测MPM肿瘤组织和MPM细胞系中是否存在SV40 TAg蛋白表达。结果PCR、Western blotting和免疫组化染色结果均显示Met5A细胞系中SV40为阳性,含有SV40 TAg基因和蛋白质。而各种MPM细胞系NCI-H28、NCI-H2052和NCI-H2452中SV40均为阴性。在12例非MPM组织和51例MPM组织中,3组低污染风险引物的PCR反应均为阴性。在12例非MPM组织和51例MPM组织中,两种抗体的免疫组化染色均未检测出SV40 TAg。结论云南省青石棉污染区MPM的发生与SV40病毒感染的关系可能不密切,青石棉暴露可能才是导致MPM发生的主要原因。

Background In Dayao County,Chuxiong Yi Autonomous Prefecture,Yunnan Province,China,5%of the surface is scattered with blue asbestos,where has a high incidence of malignant pleural mesothelioma(MPM).Simian virus 40(SV40)is a small circular double-stranded DNA polyomavirus that can cause malignant transformation of normal cells of various human and animal tissue types and promote tumor growth.Early epidemiological surveys show that the incidence of malignant mesothelioma in crocidolite contaminated areas of Dayao County is dozens of times higher than that of the general population.Objective To investigate whether the oncogenic SV40 is associated with the occurrence of MPM in the crocidolite contaminated area of Dayao County, Yunnan Province. Methods Tumor tissues from 51 patients with MPM (40 of whom had a history of asbestos exposure) and pleural tissues from 12 non-MPM patients (including diseases such as pulmonary maculopathy and pulmonary tuberculosis) were collected from January 2014 to December 2019 at the Department of Thoracic Surgery of the Fourth Affiliated Hospital of Dali University (the First People's Hospital of Chuxiong Yi Autonomous Prefecture) and People's Hospital of Dayao County. Meanwhile, human normal pleural mesothelial cell line Met5A (SV40-transformed mesothelial cells) and MPM cell lines NCI-H28 (epithelial- like type), NCI-H2052 (sarcoma-like type) and NCI-H2452 (biphasic mixed type) were cultured in vitro. After extraction of genomic DNA from each group of cells and tissues, the gene fragments of SV40 large T antigen (TAg) were amplified by polymerase chain reaction (PCR) with three sets of low contamination risk primers (SVINT, SVfor2 and SVTA1). In addition, the presence of SV40 TAg in MPM tumor tissue and MPM cell lines was detected by Western blotting and immunohistochemical staining with 2 SV40- related antibodies (Pab l01 and PAb416). Results PCR, Western blotting and immunohistochemical staining results showed that Met5A cell line had positive SV40 and contained the SV40 TAg gene and protein. In contrast, various MPM cell lines NCI-H28, NCI-H2052 and NCI-H2452 were negative for SV40. PCR reactions were negative for all three sets of low contamination risk primers in 12 non-MPM tissues and 51 MPM tissues. SV40 TAg was not detected in 12 non-MPM tissues and 51 MPM tissues by immunohistochemical staining. Conclusion The occurrence of MPM in crocidolite contaminated areas in Yunnan Province may not be closely related to SV40 virus infection, while crocidolite exposure may be the main cause of MPM.