A minigene DNA vaccine encoding peptide epitopes derived from Galectin-1 has protective antitumoral effects in a model of neuroblastoma

Cancer Lett. 2021 Jul 1:509:105-114. doi: 10.1016/j.canlet.2021.03.020. Epub 2021 Apr 10.

Abstract

We recently identified Galectin-1 (Gal-1), a β-galactoside-binding lectin, as a novel immune regulator in neuroblastoma (NB). Here, we characterized the tolerogenic function of Gal-1 within the CD8+ T cell compartment and further evaluated its relevance as an antigen for effective DNA vaccination against NB in a mouse model. NB cells with Gal-1 knockdown (NXS-2L) exhibited significantly reduced tumor growth compared to NXS-2 NB cells. Administration of anti-CD8 antibodies prevented this antitumor effect, with primary tumor growth comparable to that from Gal-1 (G1)-sufficient NB cells. Peptide epitope screening with online databases and in silico docking experiments predicted the sequences "FDQADLTI" (#1), "GDFKIKCV" (#2), and "AHGDANTI" (#3) to have superior H2-KK binding affinities and "KFPNRLNM" (#4), "DGDFKIKCV" (#5), and "LGKDSNNL" (#6) to have superior H2-DD binding affinities. Minigenes encoding G1-KK (#1-#2-#3), G1-DD (#4-#5-#6) and the triplet with the highest affinity, G1-H (#1-#2-#4), were generated and cloned into a ubiquitin-containing plasmid (pU). Mice receiving pU-G1-KK or pU-G-1H presented a reduction in the s.c. tumor volume and weight of up to 80% compared to control mice; this reduction was associated with increased cytotoxicity of isolated splenocytes from vaccinated animals. Vaccination with pUG1-DD showed a lower capability to suppress primary tumor progression. In conclusion, Gal-1 expression by NB negatively regulates CD8+ T cells. Vaccination with DNA plasmids encoding Gal-1 epitopes overcomes immune escape, enhances CD8+ T cell-dependent immunity and displays effective antitumor activity against NB.

Keywords: DNA vaccine; Galectin-1; Immunotherapy; Neuroblastoma; Salmonella typhimurium.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CD8-Positive T-Lymphocytes / drug effects
  • CD8-Positive T-Lymphocytes / immunology
  • Cancer Vaccines / genetics
  • Cancer Vaccines / immunology
  • Cancer Vaccines / pharmacology*
  • Cell Line, Tumor
  • Cytotoxicity, Immunologic / drug effects
  • Epitope Mapping
  • Female
  • Galectin 1 / genetics
  • Galectin 1 / immunology*
  • Immunodominant Epitopes*
  • Lymphocytes, Tumor-Infiltrating / drug effects
  • Lymphocytes, Tumor-Infiltrating / immunology
  • Mice
  • Neuroblastoma / drug therapy*
  • Neuroblastoma / genetics
  • Neuroblastoma / immunology
  • Tumor Burden / drug effects
  • Tumor Escape / drug effects
  • Tumor Microenvironment
  • Vaccination
  • Vaccines, DNA / pharmacology

Substances

  • Cancer Vaccines
  • Galectin 1
  • Immunodominant Epitopes
  • Lgals1 protein, mouse
  • Vaccines, DNA