Expression Of RYBP, BMI1 And LSD1 Protein In Acute Leukemia

Objective:To investigate the expression and its significance of RYBP ( Ring1 and YY1-binding protein),BMI1(B-cell specific moloney leukemia virusinsertion site 1)protein and LSD1(Lysine specific demethylase 1)in acute leukemia (AL).Methods:RYBP,BMI1and LSD1 protein level was assessed by western blot in the bone marrow mononuclear cells (BM-MNCs) of acute leukemia patients, complete remission (ALCR) patients and controls(patients without malignant hematological diseases), as well as leukemia cell line SHI-1,HL-60 and K562.The pattern of RYBP,BMI1 and LSD1 protein expression and the significance of RYBP,BMI1 and LSD1 protein expression level in leukemia patients were explored.Results:1. The expression of RYBP was positive in leukemia cell line SHI-1,HL-60 and K562 but negative in 21 controls. The RYBP was expressed in 72.5% AL patients and 13% ALCR patients. The expression rate and level of RYBP in AL was significantly higher than that in ALCR and controls (P<0.05). The expression of RYBP in AML and ALL patients was significantly higher than that in controls(P<0.05), while the expression rate and level of RYBP between AML and ALL had no statistical difference (P>0.05).2. The expression of BMI1 protein was positive in leukemia cell line SHI-1,HL-60 and K562 but negative in 8 controls as well as 24 ALCR patients. The BMI1 was expressed in 61.0% AL patients.The expression rate and level of BMI1 in AL was significantly higher than that in ALCR and controls (P<0.05). The expression of BMI1 protein in AML and ALL patients was significantly higher than that in controls(P<0.05), while the expression rate and level of BMI1 protein between AML and ALL had no statistical difference (P>0.05).3. In AML,both RYBP and BMI1 were highly expressed.The expression rate and level between RYBP and BMI1 had no significant difference and the expression of RYBP was positively correlated with that of BMI1 in AML(r=0.640,P<0.01).4. The expression of LSD1 protein was positive in leukemia cell line SHI-1,HL-60 and K562 but negative in 17 controls. The LSD1 was expressed in 78.6% AL patients and 4.2% ALCR patients. The expression rate and level of LSD1 protein in AL was significantly higher than that in ALCR and controls (P<0.05). The expression of LSD1 protein in AML and ALL patients was significantly higher than that in controls(P<0.05), while the expression rate and level of LSD1 protein between AML and ALL had no statistical difference (P>0.05).Conclusion:1. The expression of RYBP,BMI1 and LSD1 protein were low in patients without malignant hematological diseases,while that in leukemia cell line were significantly high.The expression level of RYBP,BMI1 and LSD1 protein high in newly diagnosed leukemia changed to low after complete remission.It is concluded that RYBP,BMI1 and LSD1 protein were over-expressed significantly in acute leukemia, suggesting that RYBP,BMI1 and LSD1 protein are associate with acute leukemia.They may be involved in the occurrence process of acute leukemia, thus they may be developed as biomarkers for acute leukemia.2. The expression of RYBP was positively correlated with that of BMI1 in AML. suggestting that in the pathogenesis of AML,RYBP may interact with BMI1 and PcG proteins may form unusually large protein complexes in the occureence process of acute leukemia.