Oncogenic HPV promotes the expression of the long noncoding RNA lnc-FANCI-2 through E7 and YY1

Menée à l'aide de lignées cellulaires de cancer du col utérin et d'échantillons de tissus cervicaux normaux ou lésés, cette étude met en évidence un mécanisme par lequel les papillomavirus humains oncogènes favorisent l'expression du long ARN non codant lnc-FANCI-2 via l'interaction entre la protéine E7 et le facteur de transcription cellulaire YY1

Résumé en anglais

Persistent infections of oncogenic HPVs can lead to cervical, anogenital, and head-and-neck cancers. We report that HPV-infected cervical lesions display aberrant expression of 194 long-noncoding RNAs, including lnc-FANCI-2. We show that, in cell and tissue cultures, lnc-FANCI-2 is induced primarily by the oncogenic HPV E7 protein via interacting with a cellular transcription factor YY1. HPV infection also increases YY1 protein expression by reducing miR-29a, which targets the 3′ UTR of YY1 RNA. In vivo and in vitro, the nearby DNA repair gene FANCI is co-upregulated. These findings highlight an aspect on how oncogenic HPV E7 contributes to pathogenesis.Long noncoding RNAs (lncRNAs) play diverse roles in biological processes, but their expression profiles and functions in cervical carcinogenesis remain unknown. By RNA-sequencing (RNA-seq) analyses of 18 clinical specimens and selective validation by RT-qPCR analyses of 72 clinical samples, we provide evidence that, relative to normal cervical tissues, 194 lncRNAs are differentially regulated in high-risk (HR)-HPV infection along with cervical lesion progression. One such lncRNA, lnc-FANCI-2, is extensively characterized because it is expressed from a genomic locus adjacent to the FANCI gene encoding an important DNA repair factor. Both genes are up-regulated in HPV lesions and in in vitro model systems of HR-HPV18 infection. We observe a moderate reciprocal regulation of lnc-FANCI-2 and FANCI in cervical cancer CaSki cells. In these cells, lnc-FANCI-2 is transcribed from two alternative promoters, alternatively spliced, and polyadenylated at one of two alternative poly(A) sites. About 10 copies of lnc-FANCI-2 per cell are detected preferentially in the cytoplasm. Mechanistically, HR-HPVs, but not low-risk (LR)-HPV oncogenes induce lnc-FANCI-2 in primary and immortalized human keratinocytes. The induction is mediated primarily by E7, and to a lesser extent by E6, mostly independent of p53/E6AP and pRb/E2F. We show that YY1 interacts with an E7 CR3 core motif and transactivates the promoter of lnc-FANCI-2 by binding to two critical YY1-binding motifs. Moreover, HPV18 increases YY1 expression by reducing miR-29a, which targets the 3′ untranslated region of YY1 mRNA. These data have provided insights into the mechanisms of how HR-HPV infections contribute to cervical carcinogenesis.All study data are included in the article and supporting information. The GenBank has assigned the following accession numbers for the identified lnc-FANCI-2 RNA isoforms in this report: MT669800 for lnc-FANCI-2a-PA2, MT669801 for lnc-FANCI-2a-PA1, MT669802 for lnc-FANCI-2b-PA2, MT669803 for lnc-FANCI-2b-PA1, MT669804 for lnc-FANCI-2c-PA2, MT669805 for lnc-FANCI-2c-PA1, MT669806 for lnc-FANCI-2d-PA2, MT669807 for lnc-FANCI-2d-PA1, MT669808 for lnc-FANCI-2e-PA2, MT669809 for lnc-FANCI-2e-PA1, MT669810 for lnc-FANCI-2f-PA2, MT669811 for lnc-FANCI-2f-PA1, MT669812 for lnc-FANCI-2g-PA2, and MT669813 for lnc-FANCI-2g-PA1.