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 sufficie...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(h TERT)-immortalized cells. TNFαtreatment 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 h TERTimmortalized cells, suggesting an HPV-specific role in TNFα-promoted oncogenesis. We also generated h TERT-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 micro RNAs mi R-203 and mi R-200 c. Overexpression of mi R-203 and mi R-200 c 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.展开更多
基金This work was supported in part by the UCLA School of Dentistry faculty seed grant(to K.-H.S.)two grants(R01DE18295 to M.K.K.and R01DE023348 to R.H.K.)from NIDCR/NIHa grant from UCLA Chancellor’s Office(to N.H.P.).
文摘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(h TERT)-immortalized cells. TNFαtreatment 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 h TERTimmortalized cells, suggesting an HPV-specific role in TNFα-promoted oncogenesis. We also generated h TERT-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 micro RNAs mi R-203 and mi R-200 c. Overexpression of mi R-203 and mi R-200 c 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.
