Related Experiment Video
Updated: Sep 23, 2025
Use of Interferon-γ Enzyme-linked Immunospot Assay to Characterize Novel T-cell Epitopes of Human Papillomavirus
Published on: March 8, 2012
A Reverse Structure-based Design of HPV E7 Inhibitor
Wan Chein Tan1, Shatrah Othman1,2, See Khai Lim3
1Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Background:
Human papillomavirus (HPV) is a small, non-enveloped double-stranded circular DNA virus. The high-risk types of HPV are claimed to be responsible for over 99% of cervical cancers. One of the essential HPV oncoproteins, E7, is responsible for escaping from G1/S cell cycle arrest in HPV-infected cells by binding to the retinoblastoma protein (pRb) through its LXCXE binding site.
Objective:
To design a peptide inhibitor targeting HPV E7 through an in silico approach.
Methods:
In this study, the LXCXE binding domain of pRb is used as a target to design peptide inhibitors using a reverse structure-based approach. The designed amino acid sequence from the B pocket of pRb, named peptide Y, was further investigated in vitro analysis. The cytotoxicity of the peptide was analysed in two cell lines, namely, CaSki, containing an integrated HPV16 genome, and HaCaT, an immortalized keratinocyte cell. Cell cycle analysis was also carried out in both cell lines treated with peptides.
Results:
In the in silico approach, a 9-amino acids peptide sequence formed 4 conventional hydrogen bonds with LXCXE motif was selected for in vitro assay. Based on the cytotoxicity analysis, the peptide showed low toxicity in both cell lines, where the cell viability remained over 74% when treated with peptide Y. The peptide also caused an accumulation of cells in G0/G1 (+5.4%) and S phase (+10.2%) and a reduction of cells in the G2/M phase (-14.9%) in the CaSki cells with no significant effect on normal cells, indicating it is a potential HPV inhibitor.
Conclusion:
A peptide inhibitor, peptide Y, that was designed from the LXCXE binding motif in pRb can inhibit HPV E7 by causing a cell accumulation effect in G0/G1, and S phases of the cell cycle in the HPV transformed cell lines. These findings could contribute to HPV E7 peptide inhibitor in the future.
Insights
A novel peptide inhibitor, peptide Y, was designed to target human papillomavirus (HPV) oncoprotein E7. This peptide effectively inhibits HPV E7 by disrupting the cell cycle in HPV-transformed cells with low toxicity, offering a promising therapeutic avenue.
Area of Science:
- Virology
- Molecular Biology
- Drug Discovery
Background:
- Human papillomavirus (HPV) is a DNA virus linked to over 99% of cervical cancers.
- The HPV E7 oncoprotein is crucial for cell cycle progression in infected cells by interacting with the retinoblastoma protein (pRb).
- Targeting the interaction between HPV E7 and pRb offers a potential strategy for antiviral therapy.
Purpose of the Study:
- To design a peptide inhibitor targeting the HPV E7 oncoprotein using an in silico approach.
- To evaluate the efficacy and safety of the designed peptide inhibitor in HPV-infected cell lines.
Main Methods:
- A reverse structure-based approach was employed to design peptide inhibitors targeting the LXCXE binding domain of pRb.
- In silico screening identified a 9-amino acid peptide, named peptide Y, with favorable binding interactions.
- In vitro studies included cytotoxicity assays and cell cycle analysis in CaSki (HPV-positive) and HaCaT (normal keratinocyte) cell lines.
Main Results:
- Peptide Y demonstrated low cytotoxicity, maintaining over 74% cell viability in both cell lines.
- Treatment with peptide Y led to cell cycle arrest, specifically accumulation in G0/G1 and S phases, and a reduction in G2/M phase in CaSki cells.
- No significant impact on the cell cycle was observed in normal HaCaT cells, suggesting specificity.
Conclusions:
- The designed peptide Y effectively inhibits HPV E7 by modulating the cell cycle in HPV-transformed cells.
- Peptide Y shows potential as a therapeutic agent for HPV-related cancers.
- These findings support the development of peptide-based inhibitors for HPV E7.
Related Concept Videos
01:29Viruses with RNA Genomes
00:56Viral Structure