Abstract 3789: Genomic instability changes acquired by HPV16 E6/E7 targeting multipolar mitoses aneuploidy: Cellular sequelae

Abstract

Abstract Malignant progression of high-risk Papillomavirus (HPV), associated lesions is a slow and inefficient process. HPV a non-enveloped epitheliotropic double stranded DNA virus, is an etiological agent of oral cancer. Oral cancer is related to the persistent infection by high-risk HPV type 16, E6/E7 oncoproteins. The E6/E7 complex significantly contribute to the carcinogenic genetic instability effect of high-risk HPV through the degradation of two gatekeeper proteins, p53 and pRB, respectively. This process is associated with viral genome integration into a host cellular chromosome and accumulation of numerical and structural chromosome aberrations. Viral genome integration results in consistent, sustained and dysregulated expression of the E6 and E7 oncogenes, and continued E6/E7 expression is necessary for maintenance of the transformed phenotype of HPV positive cancer cell. Induction of genomic instability by high-risk HPV E6/E7 demonstrates that HPV also drive malignant progression through targeting the nuclear and mitotic apparatus protein-1 (NuMA), and through subversion of DNA double strand break repair by HPV E6/E7 induced centrosome abnormalities. This in turn may cause abnormal localization of the microtubule protein dynein. The NuMA provides a cohesive force that guarantees the integrity of the mitotic spindle poles. However, there are no studies addressing the relationship between HPV16 infection-oral cancer, NuMA expression, and genomic instability. The aim of this study determined if HPV16 E6/E7 subverts centrosome coalescence in oral cancer caused by HPV oncogenes targeting the NuMA protein. In our experimental procedures, we proposed a novel approach to study HPV-induced chromosomal changes with reconstructed human oral epithelium in SCID mouse. We used HPV16, which is the most common HPV type found in oral cancer. Two plasmids were used to produce HPV-16 E6/E7. The first plasmid p16sheLL expresses the two viral capsid proteins, L1 and L2. The second plasmid pBR322HPV16 contains the full length HPV-16 genome. This approach closely mimics the architecture of normal human oral epithelium. In our study, we first focused on analyzing selected cellular processes involving multipolar mitoses. We examined Dynein localization in mitotic cells by immunofluorescence. We also analyzed progressive morphological and cytopathic changes in HPV-infected oral epithelia by using molecular cytogenetic analysis. In summary these data indicate that NuMA expression is alternated, and HPV16 E6/E7 oncoproteins can promote increased upregulation of genomic instability by induction of centrosome abnormalities and inhibition of DNA double strand break repair. We also found High-risk HPV16 E6/E7 oncoproteins induced mitotic defects and genetic aneuploidies through induction of supernumerary anaphase bridges, supernumerary centrosomes, and DNA double strand breaks. Citation Format: Eva McGhee, Mengtao Li, Yi-Ling Lin, Khadijah Lang, Meidrah Tyler, Judith Okoro, Mai Do, Naomi Long, Jenna Cormier, Adin Handler, Julian Handler, Sameeran Das, Benjamin Liu, Anthonia Duru, Billy Ballard, Roland Pattillo, Jay Vadgama. Genomic instability changes acquired by HPV16 E6/E7 targeting multipolar mitoses aneuploidy: Cellular sequelae [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3789.