HPV16 increases the number of migratory cancer stem cells and modulates their miRNA expression profile in oropharyngeal cancer

Introduction:

HPV16 is a major risk factor for development of oropharyngeal squamous-cell-carcinoma (OPSCC). Although HPV+ OPSCC metastasize faster than HPV- tumors, they have a better prognosis. The molecular and cellular alterations causing these differences remain elusive. In this study we examined whether expression of HPV16-E6E7 targets the number of migratory and stationary cancer stem cells (CSC). Furthermore, we wanted to elucidate if aberrantly expressed miRNAs in migratory CSC may be responible for progression of OPSCCs and whether they may serve as potential novel biomarkers for increased potential of metastasis.

Methods:

Retroviral transduction, FACS analysis, qRT-PCR, miRNA microarray, in-situ hybridization.

Results:

HPV16-E6E7 expression leads to an increase in the number of stationary (CD44high/EpCAMhigh) stem cells in primary keratinocyte cultures. Expression of E6E7 in the cell line H357 increased the migratory (CD44high/EpCAMlow) pool. This increase in migratory CSCs could also be confirmed in HPV+ OPSCC. Differentially expressed miRNAs from HPV16-E6E7 positive migratory CSCs were validated by RT-qPCR and in situ hybridization on HPV+ OPSCCs. These experiments led to the identification of miR-3194 – 5 p, which is upregulated in primary HPV16+ OPSCC and matched metastasis. MiR-1281 was found to be highly expressed in HPV+ and HPV- metastasis. As inhibition of this miRNA led to a reduction of migratory cells it may prove to be a promising drug target.

Conclusion:

Our findings highlight the capability of HPV16 to modify the phenotype of infected stem cells and that miR-1281 and miR3194 – 5 p may represent promising therapeutic targets for metastasized OPSCC.

Publication History

Publication Date:
23 April 2019 (online)