EGFR Signaling As the Nexus for HPV Oncogene Regulation

摘要 人类乳头瘤病毒（HPV）的一个子集导致世界上近5%的癌症。HPV很小 无包膜、双链DNA病毒，对鳞状上皮有嗜性。HPV是 完全依赖于正常的上皮分化来完成其复制周期。HPV感染 基底上皮细胞，在那里它们建立其基因组的染色体外复制。作为感染基底 细胞分裂，子细胞移动到上层细胞，早期病毒E6和E7的表达 蛋白质促进基底上上皮层的增殖。这导致上皮细胞的表型 HPV感染细胞的发育异常和扩增。大体上，有两种可能的结果。一个结果是 生产性感染在此，细胞分化增强，病毒E6和E7基因表达被抑制， 并且HPV晚期基因表达被激活以完成病毒生命周期并产生子代病毒体。在 第二个结果是，E6和E7蛋白的维持（去调节）表达继续促进 增殖和抑制组织分化。然而，人们对HPV癌基因如何表达 表达在上皮组织分化过程中受到调节或调节如何丧失 在致癌过程中。为了研究HPV癌基因调控，我们使用了生长为肿瘤的细胞系， 能够在器官型上皮组织培养物中重现整个HPV生命周期的组织。我们的数据表明 表皮生长因子受体（EGFR）信号和接触抑制影响HPV癌基因 表情我们发现HPV癌基因表达在转录水平下调， 随着细胞变得越来越融合，EGFR信号传导受到抑制。EGF的功效 融合细胞恢复E6和E7表达，但这可以被EGFR、MEK或ERK的抑制剂阻碍。 在这个提议中，我将定义调节E6/E7转录的EGFR效应子，并将确定EGFR的表达。 EGFR信号传导受上皮相互作用影响以影响病毒致癌基因的机制 转录。

ABSTRACT A subset of human papillomaviruses (HPVs) cause nearly 5% of the world’s cancers. The HPVs are small non-enveloped, double-stranded DNA viruses that have a tropism for squamous epithelium. HPVs are completely dependent on normal epithelial differentiation for completion of their replicative cycles. HPVs infect basal epithelial cells where they establish extra-chromosomal replication of their genomes. As infected basal cells divide and daughter cells move to the upper cell layers, the expression of the early viral E6 and E7 proteins promote proliferation of the suprabasal epithelial layers. This results in a phenotype of epithelial dysplasia and expansion of HPV infected cells. Broadly, two outcomes become possible. One outcome is a productive infection. Herein, cellular differentiation ensues, viral E6 and E7 gene expression is suppressed, and HPV late gene expression is activated to complete the virus life cycle and yield progeny virions. In the second outcome, the maintained (deregulated) expression of the E6 and E7 proteins continues to promote proliferation and inhibit tissue differentiation. However, little is known about how HPV oncogene expression is regulated during the process of epithelial tissue differentiation or how regulation is lost during carcinogenesis. To study HPV oncogene regulation, we are using cell lines that grow as neoplastic tissues able to recapitulate the entire HPV life cycle in organotypic epithelial tissue cultures. Our data indicate that epidermal growth factor receptor (EGFR) signaling and contact inhibition influence HPV oncogene expression. We find that HPV oncogene expression is transcriptionally down-regulated concomitant with suppression of EGFR signaling as cells become increasingly confluent. Furthermore, EGF stimulation of confluent cells restores E6 and E7 expression, but this can be hindered with inhibitors of EGFR, MEK, or ERK. In this proposal I will define the effectors of EGFR that regulate E6/E7 transcription and will determine the mechanism by which EGFR signaling is influenced by epithelial interactions to effect viral oncogene transcription.