Activation of HLA-G expression by 5-aza-2 - deoxycytidine in malignant hematopoetic cells isolated from leukemia patients.

Human leukocyte antigen - G (HLA-G) is a non-classical HLA class I antigen with restricted distribution in normal tissues. Ectopic HLA-G expression observed at some pathological circumstances as malignant transformation might: be triggered by epigenetic modifications such as DNA demethylation. Recently it was demonstrated that DNA methyltransferase inhibitor 5-aza-2' - deoxycytidine (AdC) induces/enhances HLA-G transcription in many leukemia cell lines of different origin. Here we investigated the effect of AdC on HLA-G expression in malignant hematopoetic cells isolated from patients with acute myeloid leukemia (AML) and chronic lymphocytic leukemia (B-CLL). We detected HLA-G expression in untreated cells from some patients. Nevertheless treatment with 5-aza-2' - deoxycytidine enhanced HLA-G transcription and concomitantly HLA-G protein synthesis in some leukemia cells.