Papillomavirus Regulation and Cancer, Institute of Medical Biology, BMSI, A*Star, Immunos, Singapore.
Cancer Res. 2010 Jul 1;70(13):5316-25. doi: 10.1158/0008-5472.CAN-09-3789. Epub 2010 Jun 8.
The viral E2 gene product plays a crucial role in the human papillomavirus (HPV) vegetative cycle by regulating both transcription and replication of the viral genome. E2 is a transcriptional repressor of the E6 and E7 viral oncogenes for HPV types 16 and 18, which are involved in cervical cancers. Using new polyclonal antibodies against the HPV16 E2 protein, we showed that E2 is expressed at various precursor stages of cervical carcinoma by immunohistochemistry on paraffin-embedded clinical samples. E2 was found to be highly expressed in the nuclei and cytoplasm of cells forming the intermediate and upper layers of cervical intraepithelial neoplasia (CIN). We could show that the expressions of E2 and p16(INK4a) (surrogate marker for oncogenic E7 expression) were exclusive in most of the cases, thus implying that E2 is not expressed together with high levels of E7. Moreover, we found that E2 is expressed in a subset of columnar cells adjacent to the CIN. We could show that expression of E2 is topologically distinct from the proliferation markers p63 and Ki67, whereas it coincides with the expression of cytokeratin K13, a marker of squamous cell differentiation. Expression of E2 also topologically coincides with episomal amplification of viral genomes in the upper layers of CIN1. These in vivo data thus validate previous assumptions of the crucial role of E2 in the early steps of HPV infection and of its negative link with expression of the viral E6 and E7 oncogenes.
病毒 E2 基因产物在人类乳头瘤病毒（HPV）的生活周期中起着至关重要的作用，通过调节病毒基因组的转录和复制。E2 是 HPV 16 和 18 型病毒癌基因 E6 和 E7 的转录抑制剂，这些基因与宫颈癌有关。我们使用针对 HPV16 E2 蛋白的新多克隆抗体，通过对石蜡包埋的临床样本进行免疫组织化学染色，显示 E2 在宫颈癌的各种前体阶段都有表达。在宫颈上皮内瘤变（CIN）的中上层形成细胞的核和细胞质中，E2 表达水平较高。我们可以证明，在大多数情况下，E2 和 p16(INK4a)（致癌 E7 表达的替代标志物）的表达是排他的，因此暗示 E2 不会与高水平的 E7 一起表达。此外，我们发现 E2 在与 CIN 相邻的柱状细胞亚群中表达。我们可以证明，E2 的表达在拓扑上与增殖标志物 p63 和 Ki67 不同，而与鳞状细胞分化标志物角蛋白 K13 的表达一致。E2 的表达也与 CIN1 上层病毒基因组的附加体扩增在拓扑上一致。这些体内数据因此验证了 E2 在 HPV 感染早期阶段的关键作用及其与病毒 E6 和 E7 癌基因表达的负相关的先前假设。
