The cancer-testis antigen NXF2 is activated by the hypomethylating agent decitabine in acute leukemia cells in vitro and in vivo

Abstract

Cancer‑testis antigens (CTAs) are a group of tumor‑associated antigens restricted to male germ cells under normal physiological conditions. CTAs are expressed in certain types of tumors and thus are a novel target for immunotherapy. Nuclear RNA export factor 2 (NXF2) is a CTA of which the expression pattern, regulation and clinical significance are unclear. In the present study, following treatment with a demethylating agent, decitabine, NXF2 expression was detected in the majority of the NXF2‑negative acute leukemia cell lines, but not in healthy donor samples. This finding was confirmed by western blot analysis. Eight primary acute leukemia bone marrow samples were treated with decitabine in vitro, and results showed that NXF2 expression was significantly upregulated. In another nine acute myeloid leukemia or myelodysplastic syndrome patients, it was noted that the expression of NXF2 was upregulated in all patients following the first cycle of decitabine, which suggested that NXF2 was activated by decitabine treatment in vivo. Furthermore, NXF2 expression in acute leukemia cells was demonstrated to be regulated by CpG island hypermethylation. To the best of our knowledge, this is the first study to demonstrate that NXF2 is activated by demethylation in acute leukemia cells in vitro and in vivo. NXF2 may therefore serve as a novel target for immunotherapy against acute leukemia.