Tseng et al. report on a DNA vaccine directed against spontaneous tumors expressing E7, a HPV-encoded oncogene expressed on many human tumors. Mice were transgenic for chimeric human HLA-A2/mouse H2Db and presented the A2 human E7(11-20) epitope. By means of oncogenic plasmid injections, E7-positive oral tumors were spontaneously induced and progressed to lethality. A vaccine consisting of E7 DNA (containing a mutation which prevents immunodominant presentation by a mouse epitope) linked to DNA from calreticulin (a heat shock protein) induced A2-restricted CD8+ responses in TILs, reduction of MDSCs in the TME, and improved survival.
Contributed by Margot O’Toole
Background: Human Papillomavirus type 16 (HPV16) has been associated with a subset of head and neck cancers. Two HPV encoded oncogenic proteins, E6 and E7, are important for the malignant progression of HPV-associated cancers. A spontaneous HPV16 E6/E7-expressing oral tumor model in human HLA-A2 (AAD) transgenic mice will be important for the development of therapeutic HPV vaccines for the control of HPV-associated head and neck cancers.
Methods: In the current studies, we characterized the HLA-A2 restricted HPV16 E7-specific CD8 + T cell mediated immune responses in the HLA-A2 (AAD) transgenic mice using a therapeutic naked DNA vaccine encoding calreticulin (CRT) linked to a mutated E7(N53S). We also employed oncogenic DNA plasmids that encoded HPV16E6/E7/Luc, NRasG12V, and sleeping beauty transposase for the transfection into the submucosal of oral cavity of the transgenic mice with electroporation to create a spontaneous oral tumor. Furthermore, we characterized the therapeutic antitumor effects of CRT/E7(N53S) DNA vaccine using the spontaneous HPV16 E6/E7-expressing oral tumor model in HLA-A2 (AAD) transgenic mice.
Results: We found that CRT/E7(N53S) DNA vaccine primarily generated human HPV16 E7 peptide (aa11-20) specific CD8 + T cells, as compared to the wild-type CRT/E7 vaccine, which primarily generated murine H-2Db restricted E7 peptide (aa49-57) specific CD8 + T cell responses. We also observed transfection of the oncogenic DNA plasmids with electroporation generated spontaneous oral tumor in all of the injected mice. Additionally, treatment with CRT/E7(N53S) DNA vaccine intramuscularly followed by electroporation resulted in significant antitumor effects against the spontaneous HPV16 E6/E7-expressing oral tumors in HLA-A2 (AAD) transgenic mice.
Conclusions: Taken together, the data indicated that the combination of HPV16 E6/E7-expressing DNA, NRasG12V DNA and DNA encoding sleeping beauty transposase is able to generate spontaneous oral tumor in HLA-A2 (AAD) transgenic mice, which can be successfully controlled by treatment with CRT/E7(N53S) DNA vaccine. The translational potential of our studies are discussed.
Author Info: (1) Department of Pathology, Johns Hopkins University, CRB II, 1550 Orleans St, Baltimore, MD, 21287, USA. (2) Department of Pathology, Johns Hopkins University, CRB II, 1550 Orlea
Author Info: (1) Department of Pathology, Johns Hopkins University, CRB II, 1550 Orleans St, Baltimore, MD, 21287, USA. (2) Department of Pathology, Johns Hopkins University, CRB II, 1550 Orleans St, Baltimore, MD, 21287, USA. (3) Department of Pathology, Johns Hopkins University, CRB II, 1550 Orleans St, Baltimore, MD, 21287, USA. (4) Department of Obstetrics and Gynecology, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 271, Cheonbo-Ro, Uijeongbu, Gyeonggi-do, 11765, Republic of Korea. (5) Department of Pathology, Johns Hopkins University, CRB II, 1550 Orleans St, Baltimore, MD, 21287, USA. (6) Department of Pathology, Johns Hopkins University, CRB II, 1550 Orleans St, Baltimore, MD, 21287, USA. chung2@jhmi.edu. Department of Oncology, Johns Hopkins University, CRB II, 1550 Orleans St, Baltimore, MD, 21287, USA. chung2@jhmi.edu. Department of Obstetrics and Gynecology, CRB II, Johns Hopkins University, 1550 Orleans St, Baltimore, MD, 21287, USA. chung2@jhmi.edu. Departments of Pathology, Oncology, and Obstetrics and Gynecology, The Johns Hopkins Medical Institutions, CRB II Room 307, 1550 Orleans St, Baltimore, MD, 21231, USA. chung2@jhmi.edu. (7) Department of Pathology, Johns Hopkins University, CRB II, 1550 Orleans St, Baltimore, MD, 21287, USA. wutc@jhmi.edu. Department of Oncology, Johns Hopkins University, CRB II, 1550 Orleans St, Baltimore, MD, 21287, USA. wutc@jhmi.edu. Department of Obstetrics and Gynecology, CRB II, Johns Hopkins University, 1550 Orleans St, Baltimore, MD, 21287, USA. wutc@jhmi.edu. Department of Molecular Microbiology and Immunology, CRB II, Johns Hopkins University, 1550 Orleans St, Baltimore, MD, 21287, USA. wutc@jhmi.edu. Departments of Pathology, Oncology, Obstetrics and Gynecology, and Molecular Microbiology and Immunology, The Johns Hopkins Medical Institutions, CRB II Room 309, 1550 Orleans St, Baltimore, MD, 21231, USA. wutc@jhmi.edu.
