Abstract:

Objective   To investigate the expression and significance of low molecular weight poly-peptide (LMP) and transporter associated with antigen processing (TAP) in leukemia cells HL-60 after induced differentiation. Methods  The cells were divided into the control group, ATRA-induced goup and PMA-induced group. Cell morphology was observed by Wright-Giemsa staining. The expressions of cell surface markers CD11b and CD14 were measured by flow cytometry. TAP1, TAP2, LMP2 and LMP7 mRNA were measured by RT-PCR, and TAP2 proteins were determined by Western blotting. Results  After treated for 72 hours, 0.8μmol/L all-trans retinoic acid (ATRA) and 50nmol/L phorbol myristate acetate (PMA) restrained the HL-60 cell proliferation and induced the cells to differentiate into the mature granulocyte and mononuclear macrophages; the expression levels of CD11b and CD14 significantly increased (all P＜0.05); there were significant changes in the expressions of TAP1, TAP2, LMP2, and LMP7 mRNA (all P＜0.05); the protein expression level of TAP2 was obviously decreased (P＜0.05). Conclusion  Leukemia-derived mononuclear cells have certain immune function phenotype, which lay the foundation for further study of LMP/TAP in leukemia immune escape.

Key words: Induced differentiation, Transporter associated with antigen processing, Phorbol myristate acetate, Low molecular weight poly-peptide, HL-60 cell, All-trans retinoic acid