Characterization of beta papillomavirus E4 expression in tumours from Epidermodysplasia Verruciformis patients and in experimental models

Abstract

This study provides a first characterisation of β-HPV life-cycle events in tumours abscised from EV patients (the human model of β-HPV-induced skin cancer), and shows how changes in E4 expression patterns relate to disease severity. β-HPV life-cycle has also been reconstructed in organotypic raft cultures created using EV-derived keratinocytes. In EV lesions and raft cultures, abundant cytoplasmic E4 expression was detectable in differentiating cells along with viral genome amplification as reported for other HPV types. E4 expression was also seen in PCNA-positive basal cells in some EV skin cancers as well as in tumours from HPV8CER (Complete Early Region) transgenic mice. In these lesions, E4 staining extended throughout the full thickness of the epithelium and was apparent in the markedly atypical cells. The loss of such staining at the tumour border suggests a distinct type of E4 dysregulation that may be exploited as a marker of viral expression during β-HPV-associated skin cancer progression.

Improved detection reveals active β-papillomavirus infection in skin lesions from kidney transplant recipients

“…33 This pattern was observed in all areas of the tumors where there was still some morphological differentiation of the epithelium. In addition, we have also demonstrated, using fluorescent in situ hybridization (FISH), that the abundance of b-HPV seen in some lesions was a direct result of genome amplification within the carcinoma tissue.…”

“…33 Antibodies to minichromosome maintenance protein 7 (MCM7) were obtained from Neomarkers (Fremont, CA, USA) (MS-862-p1).…”

“…Here, the cytopathic effect is remarkable and unequivocally similar to what is generally found in intraepidermal precursor lesions from epidermodysplasia verruciformis and HIV patients. 33,52 Many E4-positive cells are present, as well as superficial L1-positive nuclei. Unfortunately, although performed and present, we Figure 2 Distribution of the viral and cellular markers E4, L1 and minichromosome maintenance protein 7 (MCM7) in a basal cell carcinoma from a kidney transplant recipient (patient 5, neck).…”

“…[30][31][32] In these patients, HPV5 and 8 replicate very efficiently and reveal their full transforming potential, inducing multiple cutaneous neoplasia. 33,34 Emerging evidence also supports the role of b-HPV in skin cancer development in immunosuppressed individuals. Seroepidemiological studies have associated skin cancer in organ transplant recipients with the presence of anti-b-HPV antibodies, and PCR-based studies have identified b-HPV DNA in over 80% of skin tumors from these patients.…”

“…34 Overall, our results indicated that E4 staining could be exploited as a marker of viral expression during b-HPVassociated skin cancer progression as reported in the HPV8 transgenic mouse model and in cervical disease for the a-genotypes. 33,[45][46][47] To extend the data obtained so far in epidermodysplasia verruciformis patients to other groups of patients at high risk of developing skin cancer, here we studied a series of skin lesions from kidney transplant recipients attending our University Hospital by systematically analyzing for the presence of b-HPV infection both at the DNA (PCR) and protein level. Using a combination of antibodies raised against the E4 and L1 proteins of the b-genotypes, we were able to visualize the completion of viral life cycle in some precancerous lesions such as actinic keratosis or at the periphery of more advanced disease.…”