High-risk human papillomaviruses (HPVs) are involved in the development of several human cancers, including oropharyngeal squamous cell carcinomas. However, many studies have demonstrated that HPV alone is not sufficient for the oncogenic transformation of normal human epithelial cells, indicating that additional cofactors are required for the oncogenic conversion of HPV-infected cells. Inasmuch as chronic inflammation is also closely associated with carcinogenesis, we investigated the effect of chronic exposure to tumor necrosis factor α (TNFα), the major proinflammatory cytokine, on oncogenesis in two immortalized oral keratinocyte cell lines, namely, HPV16-immortalized and human telomerase reverse transcriptase (hTERT)-immortalized cells. TNFα treatment led to the acquisition of malignant growth properties in HPV16-immortalized cells, such as (1) calcium resistance, (2) anchorage independence, and (3) increased cell proliferation in vivo. Moreover, TNFα increased the cancer stem cell-like population and stemness phenotype in HPV16-immortalized cells. However, such transforming effects were not observed in hTERT-immortalized cells, suggesting an HPV-specific role in TNFα-promoted oncogenesis. We also generated hTERT-immortalized cells that express HPV16 E6 and E7. Chronic TNFα exposure successfully induced the malignant growth and stemness phenotype in the E6-expressing cells but not in the control and E7-expressing cells. We further demonstrated that HPV16 E6 played a key role in TNFα-induced cancer stemness via suppression of the stemness-inhibiting microRNAs miR-203 and miR-200c. Overexpression of miR-203 and miR-200c suppressed cancer stemness in TNFα-treated HPV16-immortalized cells. Overall, our study suggests that chronic inflammation promotes cancer stemness in HPV-infected cells, thereby promoting HPV-associated oral carcinogenesis.

中文翻译：

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促炎细胞因子TNFα通过增加癌症干度来促进HPV相关的口腔癌发生。

高危人类乳头瘤病毒（HPV）参与了几种人类癌症的发展，包括口咽鳞状细胞癌。然而，许多研究表明，单独的HPV不足以正常人上皮细胞的致癌转化，这表明HPV感染细胞的致癌转化还需要其他辅因子。由于慢性炎症也与癌变密切相关，我们研究了慢性暴露于主要的促炎细胞因子肿瘤坏死因子α（TNFα）对两种永生化口腔HPV16永生化和人类端粒酶活性的影响。逆转录酶（hTERT）永生细胞。TNFα治疗导致HPV16永生化细胞获得恶性生长特性，例如（1）钙抗性，（2）锚固独立性和（3）体内细胞增殖增加。而且，TNFα增加了HPV16永生化细胞中的癌症干细胞样种群和干性表型。但是，在hTERT永生化细胞中未观察到这种转化作用，表明HPV特异性作用于TNFα促进的肿瘤发生。我们还生成了表达HPV16 E6和E7的hTERT永生化细胞。长期暴露于TNFα可以成功诱导E6表达细胞的恶性生长和干性表型，但不诱导对照组和E7表达细胞的恶性生长和干性表型。我们进一步证明，HPV16 E6通过抑制抑制干性的microRNA miR-203和miR-200c在TNFα诱导的癌症干性中起关键作用。miR-203和miR-200c的过表达抑制了TNFα处理的HPV16永生化细胞的癌症干性。总体而言，我们的研究表明，慢性炎症会促进HPV感染细胞的癌变，从而促进HPV相关的口腔癌变。