The immortalizing and transforming ability of two common human papillomavirus 16 E6 variants with different prevalences in cervical cancer

• Published in: Oncogene Vol. 29; no. 23; pp. 3435 - 3445
• Main Authors: Richard, C, Lanner, C, Naryzhny, S N, Sherman, L, Lee, H, Lambert, P F, Zehbe, I
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10-06-2010; Nature Publishing Group
• Subjects: 631/45/612/1243; 692/699/67/1517/1371; 692/699/67/1858; Amino acid sequence; Analysis; Anoikis; Apoptosis; Biological and medical sciences; Cell Biology; Cell culture; Cell Differentiation; Cell Line, Tumor; Cell physiology; Cell Proliferation; Cell transformation and carcinogenesis. Action of oncogenes and antioncogenes; Cell Transformation, Neoplastic; Cellular biology; Cervical cancer; Cervix; Cytokeratin; Development and progression; DNA Damage; E6 protein; Enzyme Activation; Female; Female genital diseases; Fundamental and applied biological sciences. Psychology; Gene expression; Genetic aspects; Genotype & phenotype; Gynecology. Andrology. Obstetrics; Human Genetics; Human papillomavirus; Human papillomavirus 16; Humans; Identification and classification; Immortalization; Internal Medicine; Keratinocytes; Keratinocytes - metabolism; Medical sciences; Medicine; Medicine & Public Health; Molecular and cellular biology; Oncogene Proteins, Viral - genetics; Oncology; original-article; p53 Protein; Papillomaviridae; Papillomavirus E7 Proteins - genetics; Papillomaviruses; Proteomics; Repressor Proteins - genetics; Telomerase; Telomerase - metabolism; Tumor Suppressor Protein p53 - physiology; Tumors; Uterine Cervical Neoplasms - virology; transformation; immortalization; cervical cancer; human primary foreskin keratinocytes; human papillomavirus; Human; Prevalence; Papovaviridae; Malignant tumor; Carcinogenesis; Female genital diseases; Papillomavirus; Virus; Variant; Human papillomavirus 16; Human papillomavirus; Keratinocyte; Uterine cervix diseases; Cervical cancer; Cancer
• ISSN: 0950-9232; 1476-5594
• DOI: 10.1038/onc.2010.93

Persistent infection with high-risk human papillomaviruses (HPVs), especially type 16 has been undeniably linked to cervical cancer. The Asian-American (AA) variant of HPV16 is more common in the Americas than the prototype in cervical cancer. The different prevalence is based on three amino acid changes within the E6 protein denoted Q14H/H78Y/L83V. To investigate the mechanism(s) behind this observation, both E6 proteins, in the presence of E7, were evaluated for their ability to extend the life span of and transform primary human foreskin keratinocytes (PHFKs). Long-term cell culture studies resulted in death at passage 9 of vector-transduced PHFKs (negative control), but survival of both E6 PHFKs to passage 65 (and beyond). Compared with E6/E7 PHFKs, AA/E7 PHFKs were significantly faster dividing, developed larger cells in monolayer cultures, showed double the epithelial thickness and expressed cytokeratin 10 when grown as organotypic raft cultures. Telomerase activation and p53 inactivation, two hallmarks of immortalization, were not significantly different between the two populations. Both were resistant to anoikis at later passages, but only AA/E7 PHFKs acquired the capacity for
in vitro
transformation. Proteomic analysis revealed markedly different protein patterns between E6/E7 and AA/E7, particularly with respect to key cellular metabolic enzymes. Our results provide new insights into the reasons underlying the greater prevalence of the AA variant in cervical cancer as evidenced by characteristics associated with higher oncogenic potential.