PDF(Pubmed)
Abstract：
The integration of HPV DNA into human chromosomes plays a pivotal role in the onset of papillomavirus-related cancers. HPV DNA integration often occurs by linearizing the viral DNA in the E1/E2 region, resulting in the loss of a critical viral early polyadenylation signal (PAS), which is essential for the polyadenylation of the E6E7 bicistronic transcripts and for the expression of the viral E6 and E7 oncogenes. Here, we provide compelling evidence that, despite the presence of numerous integrated viral DNA copies, virus-host fusion transcripts originate from only a single integrated HPV DNA in HPV16 and HPV18 cervical cancers and cervical cancer-derived cell lines. The host genomic elements neighboring the integrated HPV DNA are critical for the efficient expression of the viral oncogenes that leads to clonal cell expansion. The fusion RNAs that are produced use a host RNA polyadenylation signal downstream of the integration site, and almost all involve splicing to host sequences. In cell culture, siRNAs specifically targeting the host portion of the virus-host fusion transcripts effectively silenced viral E6 and E7 expression. This, in turn, inhibited cell growth and promoted cell senescence in HPV16+ CaSki and HPV18+ HeLa cells. Showing that HPV E6 and E7 expression from a single integration site is instrumental in clonal cell expansion sheds new light on the mechanisms of HPV-induced carcinogenesis and could be used for the development of precision medicine tailored to combat HPV-related malignancies.
OBJECTIVE: Persistent oncogenic HPV infections lead to viral DNA integration into the human genome and the development of cervical, anogenital, and oropharyngeal cancers. The expression of the viral E6 and E7 oncogenes plays a key role in cell transformation and tumorigenesis. However, how E6 and E7 could be expressed from the integrated viral DNA which often lacks a viral polyadenylation signal in the cancer cells remains unknown. By analyzing the integrated HPV DNA sites and expressed HPV RNAs in cervical cancer tissues and cell lines, we show that HPV oncogenes are expressed from only one of multiple chromosomal HPV DNA integrated copies. A host polyadenylation signal downstream of the integrated viral DNA is used for polyadenylation and stabilization of the virus-host chimeric RNAs, making the oncogenic transcripts targetable by siRNAs. This observation provides further understanding of the tumorigenic mechanism of HPV integration and suggests possible therapeutic strategies for the development of precision medicine for HPV cancers.
OBJECTIVE: Persistent oncogenic HPV infections lead to viral DNA integration into the human genome and the development of cervical, anogenital, and oropharyngeal cancers. The expression of the viral E6 and E7 oncogenes plays a key role in cell transformation and tumorigenesis. However, how E6 and E7 could be expressed from the integrated viral DNA which often lacks a viral polyadenylation signal in the cancer cells remains unknown. By analyzing the integrated HPV DNA sites and expressed HPV RNAs in cervical cancer tissues and cell lines, we show that HPV oncogenes are expressed from only one of multiple chromosomal HPV DNA integrated copies. A host polyadenylation signal downstream of the integrated viral DNA is used for polyadenylation and stabilization of the virus-host chimeric RNAs, making the oncogenic transcripts targetable by siRNAs. This observation provides further understanding of the tumorigenic mechanism of HPV integration and suggests possible therapeutic strategies for the development of precision medicine for HPV cancers.
摘要：
HPVDNA整合到人类染色体中在乳头状瘤病毒相关癌症的发病中起着关键作用。HPVDNA整合通常通过在E1/E2区域线性化病毒DNA而发生，导致关键的病毒早期聚腺苷酸化信号（PAS）的丢失，这对于E6E7双顺反子转录物的聚腺苷酸化以及病毒E6和E7癌基因的表达是必需的。这里,我们提供了令人信服的证据，尽管存在许多整合的病毒DNA拷贝，病毒-宿主融合转录物仅来源于HPV16和HPV18宫颈癌和宫颈癌来源细胞系中的单个整合的HPVDNA。与整合的HPVDNA相邻的宿主基因组元件对于导致克隆细胞扩增的病毒致癌基因的有效表达至关重要。产生的融合RNA使用整合位点下游的宿主RNA聚腺苷酸化信号，几乎都涉及到宿主序列的剪接。在细胞培养中,特异性靶向病毒-宿主融合转录物的宿主部分的siRNA有效地沉默病毒E6和E7表达。这个,反过来,抑制HPV16+CaSki和HPV18+HeLa细胞生长，促进细胞衰老。表明来自单个整合位点的HPVE6和E7表达在克隆细胞扩增中具有重要意义，这为HPV诱导的致癌机制提供了新的思路，并可用于开发专门用于对抗HPV相关恶性肿瘤的精准医学。
目的：持续的致癌HPV感染导致病毒DNA整合到人类基因组中，并促进宫颈发育，肛门生殖器,和口咽癌。病毒E6和E7癌基因的表达在细胞转化和肿瘤发生中起关键作用。然而,如何从整合的病毒DNA表达E6和E7,该病毒DNA通常在癌细胞中缺乏病毒多腺苷酸化信号仍然未知.通过分析宫颈癌组织和细胞系中整合的HPVDNA位点和表达的HPVRNA，我们显示HPV癌基因仅从多个染色体HPVDNA整合拷贝中的一个表达。整合的病毒DNA下游的宿主聚腺苷酸化信号用于病毒-宿主嵌合RNA的聚腺苷酸化和稳定。使致癌转录物可被siRNA靶向。这一观察结果提供了对HPV整合的致瘤机制的进一步理解，并为开发HPV癌症的精准医学提供了可能的治疗策略。
目的：持续的致癌HPV感染导致病毒DNA整合到人类基因组中，并促进宫颈发育，肛门生殖器,和口咽癌。病毒E6和E7癌基因的表达在细胞转化和肿瘤发生中起关键作用。然而,如何从整合的病毒DNA表达E6和E7,该病毒DNA通常在癌细胞中缺乏病毒多腺苷酸化信号仍然未知.通过分析宫颈癌组织和细胞系中整合的HPVDNA位点和表达的HPVRNA，我们显示HPV癌基因仅从多个染色体HPVDNA整合拷贝中的一个表达。整合的病毒DNA下游的宿主聚腺苷酸化信号用于病毒-宿主嵌合RNA的聚腺苷酸化和稳定。使致癌转录物可被siRNA靶向。这一观察结果提供了对HPV整合的致瘤机制的进一步理解，并为开发HPV癌症的精准医学提供了可能的治疗策略。
