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Intracellular expression of a single-chain antibody directed against human papillomavirus type 16 E7 oncoprotein
F Wang-Johanning1, G Y Gillespie, J Grim
1Gene Therapy Program, Comprehensive Cancer Center, University of Alabama at Birmingham, 35294, USA.
Abstract:
Human papillomavirus type 16 (HPV16) E7 is a viral oncoprotein that is believed to play a major role in cervical neoplasia. Anti-HPV16 E7 intracellular single-chain antibodies (scFvs) were constructed to down-regulate HPV16 E7 oncoprotein in HPV DNA-containing cell lines. In these studies, we transfected anti-E7 scFvs into the HPV16-positive human cervical carcinoma cell lines CaSki and SiHa and tested them for their ability to inhibit cell proliferation and alter the level of HPV16 E7 oncoprotein. Our results showed that anti-HPV16 E7 scFvs inhibited cell proliferation by >85% in CaSki cells and by 95% in SiHa cells. E7 oncoprotein was down-regulated by anti-HPV16 E7 scFv, and its expression was inversely related to the amount of scFv transfected. However, there were no effects of transfecting scFvs alone in HPV-negative cell lines. These results imply that anti-HPV16 E7 scFvs only have specific anti-HPV16 E7 effects on cell proliferation and on the synthesis of virally encoded proteins in HPV-positive cell lines. Thus, transfection of HPV16 E7-positive tumors with antigen-specific scFvs may be a viable strategy for cervical cancer gene therapy.
Insights
New single-chain antibodies targeting human papillomavirus type 16 (HPV16) E7 oncoprotein show promise for cervical cancer gene therapy. These anti-HPV16 E7 scFvs effectively inhibit cancer cell proliferation and reduce viral oncoprotein levels.
Area of Science:
- Oncology
- Virology
- Molecular Biology
Background:
- Human papillomavirus type 16 (HPV16) E7 oncoprotein is a key factor in cervical neoplasia.
- Targeting viral oncoproteins is a potential strategy for cancer therapy.
Purpose of the Study:
- To develop and evaluate anti-HPV16 E7 intracellular single-chain antibodies (scFvs) for their efficacy in down-regulating HPV16 E7 oncoprotein.
- To assess the impact of these scFvs on the proliferation of HPV-positive cervical cancer cell lines.
Main Methods:
- Transfection of anti-E7 scFvs into HPV16-positive human cervical carcinoma cell lines (CaSki and SiHa).
- Assessment of cell proliferation inhibition and HPV16 E7 oncoprotein levels post-transfection.
- Control experiments using HPV-negative cell lines.
Main Results:
- Anti-HPV16 E7 scFvs significantly inhibited cell proliferation (>85% in CaSki, 95% in SiHa).
- E7 oncoprotein levels were down-regulated in an scFv dose-dependent manner.
- No effects were observed in HPV-negative cell lines, indicating specificity.
Conclusions:
- Anti-HPV16 E7 scFvs exhibit specific anti-tumor activity against HPV-positive cells.
- These scFvs effectively reduce viral oncoprotein synthesis and inhibit cell proliferation.
- Transfection with antigen-specific scFvs represents a potential gene therapy approach for HPV16-positive cervical cancers.