Modified HPV16 E7/HSP70 DNA vaccine with high safety and enhanced cellular immunity represses murine lung metastatic tumors with downregulated expression of MHC class I molecules.
OBJECTIVE
To explore whether the modified E7-HSP70, which has been introduced mutations in two zinc-binding motifs of E7, will eliminate its transformation potential and enhance the immunogenicity of fusion protein and repress E7 containing tumors with a low level of MHC-I molecules to lung metastatic in murine model.


METHODS
In this study, we examined the transforming properties of mutant E7 oncoprotein by the soft agar colony-formation assays, explored the immunogenicity of modified E7-HSP70 gene by various cellular and humor immune responses and evaluated the effect of treating lung metastatic tumor with a low expressing MHC-I molecules by tumor challenge assay and therapeutic experiment.


RESULTS
The mutant E7 oncoprotein has completely lost its transforming properties as measured in the soft agar colony-formation assays. Modified E7-HSP70 gene inducted stronger E7-specific cellular immune response than that induced by unmodified E7-HSP70. More importantly, the new construct significantly reduced the number of B16-HPV16E7 lung metastases.


CONCLUSIONS
The modified E7-HSP70 gene may be as a powerful and safe DNA vaccine in controlling the hematogenous spread of HPV16E7-associated tumors with low expression of MHC-I molecules. In addition, the B16-HPV16E7 lung metastasis model can be used to test the efficacy of various E7-specific vaccines and immunotherapeutic strategies in settings more relevant to clinical requirements.
Li
Hui
H
Center for Human Genome Research and College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P.R. China. huili0930@163.com
Ou
Xuan
X
Xiong
Jinhu
J
D000818:Animals; D000918:Antibody Specificity; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D019496:Cancer Vaccines / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D002472:Cell Transformation, Viral / Q000235:genetics / Q000276:immunology; D005260:Female; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis / Q000235:genetics; D007371:Interferon-gamma / Q000096:biosynthesis / Q000235:genetics; D008175:Lung Neoplasms / Q000276:immunology / Q000556:secondary / Q000628:therapy*; D008546:Melanoma, Experimental / Q000276:immunology / Q000556:secondary / Q000628:therapy*; D051379:Mice; D008810:Mice, Inbred C57BL; D041681:NIH 3T3 Cells; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000276:immunology*; D050725:Papillomavirus E7 Proteins; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D015854:Up-Regulation; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*
D019496:Cancer Vaccines; D018840:HSP70 Heat-Shock Proteins; D015395:Histocompatibility Antigens Class I; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D011993:Recombinant Fusion Proteins; D019444:Vaccines, DNA; C059731:oncogene protein E7, Human papillomavirus type 16; D007371:Interferon-gamma