As cancer stem cells (CSCs) are resistant to chemotherapy, radiotherapy and targeted molecular therapy, immunotherapy of tumors could be aimed at their elimination. Markers specific for CSCs have not been identified to date, but microarray analyses have shown that CSCs and embryonic stem cells use similar transcriptional programs, thus suggesting the production of shared transcription factors. In this study, we developed an experimental DNA vaccine against the transcription factor Sox2 that is important for self-renewal of stem cells and is overexpressed in numerous human cancers. The Sox2 gene was codon optimized for the expression in human cells, its sequences encoding two nuclear localization signals (NLSs) were mutagenized, and the sequence coding for the PADRE helper epitope was fused with its 5' terminus. While codon optimization did not increase Sox2 production and mutagenesis in NLSs only partially reduced nuclear localization of Sox2, the addition of the PADRE epitope was crucial for the enhancement of Sox2 immunogenicity. The antitumor effect was shown after immunization against mouse oncogenic TC-1/B7 cells derived from the lung cancer cell line TC-1 and characterized by high Sox2 production. Sox2-specific reactivity in an ELISPOT assay was further augmented by the depletion of regulatory T (Treg) cells, but this depletion did not enhance the antitumor effect. These data demonstrated the induction of immune responses against the Sox2 self-antigen, but did not confirm the usefulness of Treg depletion when combined with antitumor vaccination.

• MeSH
• buněčné jádro metabolismus   MeSH
• buňky NIH 3T3 MeSH
• DNA vakcíny farmakologie   MeSH
• imunizace MeSH
• lidé MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádorové kmenové buňky metabolismus   patologie   MeSH
• nádory plic patologie   MeSH
• regulační T-lymfocyty metabolismus   MeSH
• transkripční faktory SOXB1 antagonisté a inhibitory   genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Therapeutic DNA vaccines against oncogenic infection with human papillomavirus type 16 (HPV16) are mostly targeted against viral oncoproteins E7 and E6. To adapt the E7 oncoprotein for DNA immunization, we have previously reduced its oncogenicity by modification of the Rb-binding site and enhanced immunogenicity of the modified E7GGG gene by the fusion with the 5'-terminus of the gene encoding E. coli beta-glucuronidase (GUS). In this study, we attempted to improve immunogenicity of the GUS-based anti-E7 vaccines by increasing the steady-state level of fusion proteins. We fused deletion mutants of E7GGG and codon-optimized E7GGG with the 5'-terminus of GUS and unaltered E7GGG with the 3'-terminus of GUS. Furthermore, we mutated the initiation codon of the GUS gene in the E7GGG.GUS construct, as GUS alone was produced from this fusion gene. We found that only the fusion of E7GGG with the 3'-terminus of GUS (GUS.E7GGG) and deletion mutants of E7GGG with the 5'-terminus of GUS increased the steady-state level of fusion proteins in transfected human 293T cells. Analysis of immune reactions induced in mice by vaccination via a gene gun showed that the increased steady-state level of fusion proteins resulted in augmented production of E7-specific antibodies, but did not enhance cell-mediated anti-tumor immunity. Finally, we joined the signal sequence of the adenoviral E3 protein with GUS.E7GGG. This modification led to the predominant localization of the fusion protein in the endoplasmic reticulum and enhancement of CD8+ T-cell response, while antibody production was reduced. In conclusion, we found modifications of the E7GGG.GUS fusion gene that augmented either humoral or cell-mediated immune responses.

• MeSH
• buňky NIH 3T3 MeSH
• cytotoxické T-lymfocyty imunologie   MeSH
• DNA vakcíny imunologie   MeSH
• financování organizované MeSH
• glukuronidasa genetika   imunologie   MeSH
• lidský papilomavirus 16 imunologie   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• onkogenní proteiny virové genetika   imunologie   MeSH
• Papillomavirus E7 - proteiny MeSH
• protilátky virové krev   MeSH
• rekombinantní fúzní proteiny imunologie   MeSH
• vakcíny proti papilomavirům imunologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH