Live cell, image-based high-throughput screen to quantitate p53 stabilization and viability in human papillomavirus positive cancer cells

Approximately 5% of cancers are caused by high-risk human papillomaviruses. Although very effective preventive vaccines will reduce this cancer burden significantly over the next several decades, they have no therapeutic effect for those already infected and remaining at risk for malignant progression of hrHPV lesions. HPV-associated cancers are dependent upon the expression of the viral E6 and E7 oncogenes. The oncogenic function of hrHPV E6 relies partially on its ability to induce p53 degradation. Since p53 is generally wildtype in hrHPV-associated cancers, p53 stabilization arrests proliferation, induces apoptosis and/or results in senescence. Here we describe a live cell, image-based high-throughput screen to identify compounds that stabilize p53 and/or affect viability in HPV-positive cancer HeLa cells. We validate the robustness and potential of this screening assay by assessing the activities of approximately 6,500 known bioactive compounds, illustrating its capability to function as a platform to identify novel therapeutics for hrHPV.

The papillomavirus E5 gene does not affect EGFR transcription and overall survival in cervical cancer

INTRODUCTION

The human papillomavirus (HPV) E5 gene encodes a small and highly hydrophobic oncoprotein that affects immune evasion, cell proliferation, loss of apoptotic capacity and angiogenesis in tumors. E5 shows an affinity for biological membranes and was associated with an increase of epidermal growth factor/epidermal growth factor receptor (EGF/EGFR) signaling through the accumulation of EGFR in cellular membranes. Due to the frequent integration of the HPV genome into the host cell genome, E5 is frequently not transcribed in cervical tumors.

AIM

In this study we looked forward to verifying whether the potential expression of E5 protein in human papillomavirus 16 positive (HPV16⁺ ) and human papillomavirus 18 positive (HPV18⁺ ) cervical tumors was associated with levels of EGFR and vascular endothelial growth factor A (VEGFA) transcription and with patients overall survival.

RESULTS

Association between the presence of E5 transcripts and viral genome disruption was observed for HPV16⁺ and HPV18⁺ tumors. Association was not observed between tumors potentially capable of translating E5 and EGFR or VEGFA transcriptional levels. Similarly, the capability of translating E5 and overall survival in patients with HPV16⁺ squamous cell carcinoma tumors stage ≥ IB2 were not associated.

CONCLUSION

The likely presence of E5 transcripts was neither associated to a higher activity of the EGFR-VEGFA pathway nor to the overall survival of patients with HPV16⁺ squamous cell carcinoma in stages ≥ IB2.

[Risk factors and prevalence of HPV infection in patients from Basic Health Units of an University Hospital in Southern Brazil]

PURPOSE

To determine the HPV prevalence and genotypes and to identify factors associated with infection in pregnant and non-pregnant women with positive or negative HIV-1, treated in Gynecology and Obstetrics Ambulatories and in Health Primary Units, in Rio Grande, Rio Grande do Sul State, Brazil.

METHODS

Cervical cells samples from 302 patients were analyzed for HPV presence and genotypes were determined by nested and sequencing polymerase chain reaction. We calculated prevalence ratios associated with the studied variables by Fisher's exact or χ² tests, and Poisson's regression. Women with insufficient material were excluded from the study.

RESULTS

HPV was detected in 55 of the 302 women included in the study (18.2%); of these, 31 were pregnant, showing a significant association for HPV (p=0.04) when compared to non-pregnant ones. Risk factors for the infection were: patients aged <20 years-old (p=0.04), early initiation of sexual life (p=0.04), absence of cytological test (p=0.01), diagnosis of altered cytology (p=0.001), and counting <349 cells/mm³ (p=0.05). However, multi-parity was found to be a protective factor for the infection (p=0.01). Multivariate analysis showed that age <20 years-old (PR=2.8; 95%CI 1.0 - 7.7, p=0.04) and an altered cytological result (PR=11.1; 95%CI 3.0 - 4.1, p=0.001) were significantly associated with infection. HPV genotype was determined in 47 samples (85.4%) presenting one genotype per infection: eight HPV 16 and 58; six HPV 6; four HPV 18 and 33; three HPV 53 and 82; two HPV 83 and 61; one HPV 31, 35, 45, 64, 68, 71 and 85.

CONCLUSIONS

The prevalence of HPV detection was 18.2%, the most frequent genotypes were 16 and 58, and sociodemographic and gynecological factors were associated with viral infection.

The effect of combined polymorphisms in chemokines and chemokine receptors on the clinical course of HIV-1 infection in a Brazilian population

Polymorphisms in genes that encode chemokines or their receptors can modulate susceptibility to human immunodeficiency virus (HIV) infection and disease progression. The objective of this study was to assess the frequency of polymorphisms CCR5-Δ32, CCR2-64I, CCR5-59029A and SDF1-3'A and their role in the course of HIV infection in a Southern Brazilian population. Clinical data were obtained from 249 patients for an average period of 6.4 years and genotypes were determined by standard polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism. Survival analyses were conducted for three outcomes: CD4+ T-cell counts below 200 cells/µL, acquired immune deficiency syndrome (AIDS) or death. The frequency of the polymorphisms CCR5-Δ32, CCR2-64I, CCR5-59029A and SDF1-3'A were 0.024, 0.113, 0.487 and 0.207, respectively. CCR5-Δ32 was associated with a reduction in the risk for CD4+ T-cell depletion and with an increased risk for death after AIDS diagnosis. CCR2-64I was associated with a reduction in the risk for developing AIDS. SDF1-3'A was also associated with decreased risk for AIDS, but its effect was only evident when CCR2-64I was present as well. These results highlight the possibility of using these markers as indicators for the prognosis of disease progression and provide evidence for the importance of analysing the effects of gene polymorphisms in a combined fashion.