Abstract

The notch family of transmembrane receptors play crucial roles in cell fate determination through interaction with the Delta/Serrate /Lag-2 family of ligands. The transcription of the hairyl enhancer of split (HES-1) gene is one of the known target of notch signaling. Notch1 is involved in the pathogenesis of T-acute lymphoblastic leukemia (T-ALL) carrying the very rare translocation t (7;9)(q34;q34.3). However, the function of Notch signaling in leukemogenesis is currently still unclear. To investigate the possible role of notch signaling in human acute leukemia,A quantitative real-time reverse transcriptase polymerase chain reaction (RQ-RT-PCR) method has been established for detecting expression levels of Notch1~2, Jagged1, Delta1, Hes1 and internal reference GAPDH in primary BM samples of 34 acute leukemia patients and 11 normal controls by LightCycler using TaqMan probe; 34 pretreated acute leukemia patients includes 16 acute lymphoblastic leukemia (7 T-ALL, 9 B-ALL) and 18 acute myeloblastic leukemia (10 M1,3 M2,3 M3 and 2 M5) In all of these cases the leukemia blast cells are more than 80%.

The results demonstrated as the follows: The average expression levels of Notch1 in 16 ALL were statistically higher than that in 11 normal and 18 AML [ 13225.0±3306.3 (16) vs 1725.6±1237.8 (11) vs 2354.8±2985.6(18), F=7.85, P<0.01, ] There was no statistically difference between normal and AML group( P>0.05); the average expression levels of Notch2 did not have statistically difference among ALL, normal and AML.[143671.7±372814.9 (16) vs 52178.2±36747.5 (11) vs 66520.2±62643.2 (18) F=0.15, P>0.05 ]. The average expression levels of Jagged1 in 16 ALL were statistically less than that in 18 AML and 11 normal [129.9±353.8(16) vs 375.4±697.5(18) vs 2212.5±3371.7(11), F=20.23, P<0.01] while the jagged1 level was significantly lower in AML than in normal. The average levels of Delta1 in 16 ALL were statistically higher than that in normal and AML[30884.6±104097.1(16) vs 2299.8±4301.4(11) vs 579.7±641.7(18), F=5.78, P<0.01], and no statistically difference between AML and normal has been found. The average levels of Hes1 in AML were statistically less than normal and ALL[20.1±20.1(18) vs 1013.2±2507.0 (11) vs 244.5±347.3(16), F=6.62, P<0.01, there were no statistically difference between normal and ALL,(P.>0.05)]. In addition, the average levels of Delta1 in 9 B-ALL were statistically higher than those in 7 T-ALL[60316.6±145713.4(9) vs 378.0±238.6 (7), t=4.356, p=0.001]., the average expression levels of Notch1~2, Jagged1 and Hes1 in B-ALL were no statistically difference compare to T-ALL. In conclusion, Notch1 and Delta1 expression levels in ALL were statistically higher than that in normal and AML group, there were no statistically difference between normal and AML. Jagged1 expression levels in ALL were statistically less than that in AML and least in normal. Hes1 expression levels in AML were statistically less than that in normal and ALL, while no statistically difference could be found between normal and ALL groups. Taking altogether, in AL, the expression of Hes1 had not been found upregulated, instead was downregulated in AML. No statistically difference in Notch2 expression has been found among AML, ALL and normal group. In addition, Delta1 expression levels in B-ALL were statistically higher than that in T-ALL.

Author notes

Corresponding author