Institute for Virology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.
University of Bonn, Faculty of Mathematics and Natural Sciences, Life & Medical Sciences (LIMES) Institute, Bonn, Rheinland-Pfalz, Germany.
Front Immunol. 2024 Feb 2;15:1335302. doi: 10.3389/fimmu.2024.1335302. eCollection 2024.
Human papillomaviruses (HPVs) are a major cause of cancer. While surgical intervention remains effective for a majority of HPV-caused cancers, the urgent need for medical treatments targeting HPV-infected cells persists. The pivotal early genes E6 and E7, which are under the control of the viral genome's long control region (LCR), play a crucial role in infection and HPV-induced oncogenesis, as well as immune evasion. In this study, proteomic analysis of endosomes uncovered the co-internalization of ErbB2 receptor tyrosine kinase, also called HER2/neu, with HPV16 particles from the plasma membrane. Although ErbB2 overexpression has been associated with cervical cancer, its influence on HPV infection stages was previously unknown. Therefore, we investigated the role of ErbB2 in HPV infection, focusing on HPV16. Through siRNA-mediated knockdown and pharmacological inhibition studies, we found that HPV16 entry is independent of ErbB2. Instead, our signal transduction and promoter assays unveiled a concentration- and activation-dependent regulatory role of ErbB2 on the HPV16 LCR by supporting viral promoter activity. We also found that ErbB2's nuclear localization signal was not essential for LCR activity, but rather the cellular ErbB2 protein level and activation status that were inhibited by tucatinib and CP-724714. These ErbB2-specific tyrosine kinase inhibitors as well as ErbB2 depletion significantly influenced the downstream Akt and ERK signaling pathways and LCR activity. Experiments encompassing low-risk HPV11 and high-risk HPV18 LCRs uncovered, beyond HPV16, the importance of ErbB2 in the general regulation of the HPV early promoter. Expanding our investigation to directly assess the impact of ErbB2 on viral gene expression, quantitative analysis of E6 and E7 transcript levels in HPV16 and HPV18 transformed cell lines unveiled a noteworthy decrease in oncogene expression following ErbB2 depletion, concomitant with the downregulation of Akt and ERK signaling pathways. In light of these findings, we propose that ErbB2 holds promise as potential target for treating HPV infections and HPV-associated malignancies by silencing viral gene expression.
人乳头瘤病毒（HPV）是癌症的主要病因。虽然手术干预对大多数 HPV 引起的癌症仍然有效，但针对 HPV 感染细胞的医疗治疗方法仍然迫切需要。病毒基因组的长控制区（LCR）控制下的早期关键基因 E6 和 E7 在感染和 HPV 诱导的致癌作用以及免疫逃逸中起着至关重要的作用。在这项研究中，内体的蛋白质组分析揭示了表皮生长因子受体酪氨酸激酶 ErbB2 与来自质膜的 HPV16 颗粒的共内化。虽然 ErbB2 的过表达与宫颈癌有关，但它对 HPV 感染阶段的影响以前是未知的。因此，我们研究了 ErbB2 在 HPV 感染中的作用，重点是 HPV16。通过 siRNA 介导的敲低和药理学抑制研究，我们发现 HPV16 的进入不依赖于 ErbB2。相反，我们的信号转导和启动子测定揭示了 ErbB2 通过支持病毒启动子活性对 HPV16 LCR 具有浓度和激活依赖性的调节作用。我们还发现 ErbB2 的核定位信号对于 LCR 活性不是必需的，而是细胞 ErbB2 蛋白水平和被 tucatinib 和 CP-724714 抑制的激活状态。这些 ErbB2 特异性酪氨酸激酶抑制剂以及 ErbB2 的耗竭显著影响下游 Akt 和 ERK 信号通路和 LCR 活性。涵盖低风险 HPV11 和高风险 HPV18 LCR 的实验除了 HPV16 之外，还揭示了 ErbB2 在 HPV 早期启动子的一般调控中的重要性。通过直接评估 ErbB2 对病毒基因表达的影响，对 HPV16 和 HPV18 转化细胞系中 E6 和 E7 转录本水平的定量分析揭示了 ErbB2 耗竭后癌基因表达的显著下降，同时 Akt 和 ERK 信号通路的下调。鉴于这些发现，我们提出 ErbB2 作为通过沉默病毒基因表达来治疗 HPV 感染和 HPV 相关恶性肿瘤的潜在靶点的可能性。
