Treatment of chronic lymphocytic leukemia with a hypomethylating agent induces expression of NXF2, an immunogenic cancer testis antigen.
OBJECTIVE
Critical to the success of active immunotherapy against cancer is the identification of immunologically recognized cancer-specific proteins with low tolerogenic potential. Cancer testis antigens (CTA), in particular, fulfill this requirement as a result of their aberrant expression restricted to cancer cells and lack of expression in normal tissues bypassing tolerogenic mechanisms against self. Although CTAs have been extensively studied in solid malignancies, little is known regarding their expression in chronic lymphocytic leukemia (CLL).


METHODS
Using a two-pronged approach we evaluated the immunogenicity of 29 CTAs in 22 patients with CLL and correlated these results to reverse transcriptase PCR data from CLL cell lines and patient cells.


RESULTS
We identified IgG-specific antibodies for one antigen, NXF2, and confirmed this response by ELISA and Western blot. We found that treatment of CLL with 5-aza-2'-deoxycytidine can induce expression of NXF2 that lasted for several weeks after treatment. Treatment also increased levels of MHC and costimulatory molecules (CD80, CD86, and CD40) necessary for antigen presentation. In addition, we identified other promising antigens that may have potential immunotherapeutic application.


CONCLUSIONS
Our findings suggest that NXF2 could be further pursued as an immunotherapeutic target in CLL, and that treatment with demethylating agents could be exploited to specifically modulate CTA expression and effective antigen presentation in malignant B cells.
Dubovsky
Jason A
JA
H Lee Moffitt Cancer Center, Tampa, FL, USA.
McNeel
Douglas G
DG
Powers
John J
JJ
Gordon
John
J
Sotomayor
Eduardo M
EM
Pinilla-Ibarz
Javier A
JA
D000328:Adult; D000368:Aged; D000951:Antigens, Neoplasm / Q000097:blood / Q000235:genetics / Q000276:immunology*; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D018122:B7-1 Antigen / Q000276:immunology; D051940:B7-2 Antigen / Q000276:immunology; D015153:Blotting, Western; D019013:CD40 Antigens / Q000276:immunology; D002460:Cell Line; D019175:DNA Methylation / Q000187:drug effects; D015254:DNA Modification Methylases / Q000037:antagonists & inhibitors; D000077209:Decitabine; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000097:blood / Q000188:drug therapy / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014407:Tumor Cells, Cultured
D000951:Antigens, Neoplasm; D000964:Antimetabolites, Antineoplastic; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D019013:CD40 Antigens; D007074:Immunoglobulin G; C542434:cancer testis antigen NXF2, human; D000077209:Decitabine; D015254:DNA Modification Methylases; D001374:Azacitidine