人宫颈癌FHIT基因的表达改变与HPV16感染的关系

Fragile histidine triad transcription abnormalities and human papillomavirus16 infection in human cervical carcinoma

目的探讨FHIT基因表达改变和HPV16感染与人宫颈癌发生的关系。方法采用反转录-巢式聚合酶链反应方法测定5种人宫颈癌细胞株(SiHa、HeLa、RJC-1、CS1213、C4-1)和58例宫颈癌组织与18例正常宫颈对照中FHIT mRNA的表达;回收7例FHIT基因不同的转录扩增产物,纯化后进行DNA测序;PCR技术检测组织中HPV16型的感染状况。结果SiHa、HeLa和C4-1宫颈癌细胞中有FHIT基因转录异常;宫颈癌组织中39例(67.2%)存在FHIT基因异常表达,显著高于正常对照组0例(0%)(P<0.05);37例(63.8%)有HPV16感染,显著高于正常对照组1例(5.0%)(P<0.05)。宫颈癌组织中有HPV16感染患者的FHIT基因表达异常数(30/37)显著高于HPV16未感染的患者(9/21),二者之间存在相关性(P<0.01);FHIT基因的异常表达和HPV16的感染与患者的年龄、临床分期、肿瘤直径、病理分级及是否伴淋巴结转移无相关性(P>0.05)。序列分析发现FHIT基因转录本主要存在不同程度的外显子的缺失,以第5位和第6位外显子的缺失为主,未见未知序列的插入和点突变。结论FHIT基因在人宫颈癌组织中的异常表达率明显增高,且与HPV16的感染有关,这些改变可能在人宫颈鳞癌的发生中起着重要作用。

Objective To evaluate the relationship between fragile histidine triad （FHIT） transcription abnormalities and HPV16 infection and human cervical tumorigenesis. Methods Total RNA from 5 cervical carcinoma cell lines （SiHa, HeLa, RJC-1, CS1213 and C4-1）, 58 primary cervical cancer specimens and 18 normal cervical epithelial tissues were extracted and FHIT transcripts were characterized by a two-step（nested） reverse transcription （RT）-PCR. The seven of the PCR products with different size were purified and sequenced. HPV16 infection was assessed by PCR. Results （1） There were altered FHIT transcripts in SiHa, HeLa and C4-1 cells. Aberrant FHIT transcripts were detected in 39 out of the 58 cervical cancer samples （67.2%）, but none out of 18 in the normal cervix tissue specimens （0%）; HPV16 infections were identified in 37 of the 58 cervical cancer tissues （63.8%）, but 1 in the 18 normal cervical epithelial tissues （5%）, which showed a significant difference between these two groups （P〈 0. 05）. （2） The number of partial deletions of the FHIT gene in the group with HPV16 infection （29/37） was significantly higher than that in the group without HPV16 infection （9/21） and the correlation was found between aberration of FHIT transcript and HPV16 infection. There was no obvious difference in age, stage, tumor size, grade and lymph node metastasis between the groups with and without FHIT abnormalities and HPV16 infection （P〉0.05）. （3） The exon 5 and exon 6 were mainly deleted in the altered FHIT transcripts and no insertion and point mutation were found by DNA sequencing. Conclusion Aberrant FHIT expression was significantly common in cervical cancers and was correlated with HPV16 infection. These findings suggest that the tumor suppressor gene FHIT and high risk HPV16 may play a very important role in human cervical carcinogenesis.