Abstract B23: Role of noncoding RNAs in regulating human papilloma virus-16 (HPV-16) induced oncogenesis in head and neck squamous cell carcinoma (HNSCC)

Abstract

Abstract Background: HPV is an emerging risk factor for HNSCC, however, molecular mechanisms in HPV mediated HNSCC remains poorly delineated. Recent studies suggest that non-coding RNAs may play an important role in the aetiology of HNSCC. In the present study, we examined microRNAs involved in HPV-16 induced HNSCC. Material and Method: Tissue samples from HNSCC patients (n=300) were screened for HPV-16 using PCR based approach with consensus PCR primers (MY09/MY11, Gp5+/Gp6+), HPV16-specific PCR, HPV-16 E7 mRNA, immunohistochemistry (p16, p53 and pRB) and viral-load determination. In-silico approach was used to identify host miRNAs with HPV-16 mRNAs as putative target. Differential expression of identified miRNAs was determined by qRT-PCR in HPV-16 positive (UPCI:SCC090, CaSki, SiHa), HPV negative (UPCI:SCC116, HaCat) and transfected with HPV 16 full genome plasmid cell lines, and, HPV 16-positive/HPV-negative tissue samples. Putative targets of identified miRNAs were identified by bioinformatic approach and their mRNA levels were determined by qRT-PCR in HPV positive and negative cell lines, and tissue samples. Over-expression and inhibition studies with miRNA mimic and inhibitor were done to identify affected viral and host oncogenic pathways. Results: Total 32 HNSCC patients were found to be HPV-16 positive. We identified 10 miRNAs with HPV-16 as putative target. Among them hsa-miR-139-3p showed significant down-regulation in HPV-16 positive samples and cell lines compared to HPV negative controls. Using bioinformatics tools, hsa-miR-139-3p was found to target viral HPV-16 E1 and host HOXB6 gene. Transfection with hsa-miR-139-3p mimic resulted in significant down-regulation of HPV 16 early mRNA as well as its targeted genes in luciferase-3'UTR assay. Moreover, mimic transfected HPV-positive cell lines showed dysregulated MEK-ERK signaling pathway. Conclusion: Our results suggest hsa-miR-139-3p may be involved in patho-physiology of HPV-16 positive HNSCC as it deregulates expression of HPV oncogenic proteins and cell proliferation by targeting MEK-ERK signaling pathway. Citation Format: Malay Kumar Sannigrahi, Varinder Singh, Rajni Sharma, Naresh K. Panda, Madhu Khullar. Role of noncoding RNAs in regulating human papilloma virus-16 (HPV-16) induced oncogenesis in head and neck squamous cell carcinoma (HNSCC). [abstract]. In: Proceedings of the AACR Special Conference on Noncoding RNAs and Cancer: Mechanisms to Medicines ; 2015 Dec 4-7; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2016;76(6 Suppl):Abstract nr B23.