Increased PRAME antigen-specific killing of malignant cell lines by low avidity CTL clones, following treatment with 5-Aza-2'-Deoxycytidine

Cancer Immunol Immunother. 2011 Sep;60(9):1243-55. doi: 10.1007/s00262-011-1024-4. Epub 2011 May 7.


The cancer testis antigen Preferentially Expressed Antigen of Melanoma (PRAME) is overexpressed in many solid tumours and haematological malignancies whilst showing minimal expression in normal tissues and is therefore a promising target for immunotherapy. HLA-A0201-restricted peptide epitopes from PRAME have previously been identified as potential immunogens to drive antigen-specific autologous CTL responses, capable of lysing PRAME expressing tumour cells. CTL lines, from 13 normal donors and 10 melanoma patients, all of whom were HLA-A0201 positive, were generated against the PRAME peptide epitope PRA(100-108). Specific killing activity against PRA(100-108) peptide-pulsed targets was weak compared with CTL lines directed against known immunodominant peptides. Moreover, limiting dilution cloning from selected PRAME-specific CTL lines resulted in the generation of a clone of only low to intermediate avidity. Addition of the demethylating agent 5-aza-2'-Deoxycytidine (DAC) increased PRAME expression in 7 out of 11 malignant cell lines including several B lineage leukaemia lines and also increased class I expression. Pre-treatment of target cells was associated with increased sensitivity to antigen-specific killing by the low avidity CTL. When CTL, as well as of the target cells, were treated, the antigen-specific killing was further augmented. Interestingly, one HLA-A0201-negative DAC-treated line (RAJI) showed increased sensitivity to killing by clones despite a failure of expression of PRAME or HLA-A0201. Together these data point to a general increased augmentation of cancer immunogenocity by DAC involving both antigen-specific and non-specific mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibody Affinity
  • Antigens, Neoplasm / immunology*
  • Antigens, Neoplasm / metabolism
  • Antimetabolites, Antineoplastic / pharmacology
  • Azacitidine / analogs & derivatives*
  • Azacitidine / pharmacology
  • Cell Line, Tumor
  • Cytotoxicity, Immunologic / immunology
  • Decitabine
  • HL-60 Cells
  • HLA-A2 Antigen / immunology
  • Humans
  • Immunotherapy, Adoptive / methods*
  • K562 Cells
  • Neoplasms / immunology*
  • Neoplasms / therapy*
  • T-Lymphocytes, Cytotoxic / immunology*
  • Transfection


  • Antigens, Neoplasm
  • Antimetabolites, Antineoplastic
  • HLA-A*02:01 antigen
  • HLA-A2 Antigen
  • PRAME protein, human
  • Decitabine
  • Azacitidine