Expression Analysis Of Notch1and Jagged1in Children Acute Leukemia And Its Clinical Significance

[Objectives]The present study was initiated to explore the potential involvement ofNotch signaling pathway in children acute leukemia (AL) by studying theexpression profile of Notch and Notch1protein in bone marrow (BM)/peripheral blood (PB) mononuclear cells of children AL using RT-PCR andimmunocytochemistry (ICC). Our study would shed novel light on theunderlying mechanism of AL and be helpful to find a new therapeutic target forthis complicated pathogenesis.[Methods]Part1Using RT-PCR, we examined the expression levels of Notch1andJagged1in BM and PB mononuclear cells in47children AL (consisting of6cases of T-ALL，26cases B-ALL and15cases of AML) and20controls(normal children or children with nonmalignant hematologic disease) at thetranscriptional level. The amplification of β-actin mRNA was served as internalcontrol. Accordingly, results in terms of specific targets expression levels foreach sample were normalized to those of the internal control β-actin. Part2The Notch1protein was immunolocalized by (ICC) in bonemarrow smears of42cases of children AL. The samples included7T-ALLs，25B-ALLs and10AMLs, with samples from22control（schildren with nomaliganthematologic disease) in the same period serving as the parallel control.Subsequent quantification analysis was carried out by counting the relativepercentage and immunoreactive density of cells that showed positive Notch1staining in100randomly selected cells of a high power field.[Results]Part1The positive rate of Notch1mRNA in the ALL and AML groupswas higher than that in the control group (P<0.05). However, we did not find thestatistically significant difference of the positive rate of Notch1mRNA betweenthe ALL group and AML group (P>0.05). In contrast, the expression level ofNotch1in ALL and AML groups was not different from the control group (P>0.05). The expression level of Notch1in ALL children was not different fromthe AML group, either (P>0.05).The positive rate of Notch1in the T-ALL group was not significantlydifferent from that in the B-ALL group (P>0.05), however, the expression levelof Notch1in T-ALL children was much higher than that in B-ALL children(t=3.835, P=0.001).The positive rate of the Jagged1in the ALL group and the AML groupwas not statistically different from that in the control group (P>0.05). Thepositive rate of the Jagged1in the ALL group was not different from that inAML group (P>0.05). Furthermore, the expression level of Jagged1in the ALLand AML groups were much higher than that in the control group (P<0.05). Theexpression level of Jagged1in ALL children was not different from that in theAML group (P>0.05). The positive rates of the Jagged1and the expression levels of the Jagged1in the T-ALL group was not different from that in the B-ALL group (P>0.05).By using semi-quantitative analysis, we found that Notch1mRNA andJagged1mRNA levels were not statistically significant difference between MBand PB, which were obtained from12newly diagnosed children patients.Part2The positive expression rate of the Notch1protein in the T-ALLgroup and the AML group was higher than that in the control group (P<0.05).Contrarily, the positive expression rate of the Notch1protein in the B-ALLgroup and in the ALL were not different from that in the control group (P>0.05).A neglectigible difference of the Notch1-positive staining was also observedbetween ALL and control groups (P>0.05). The positive rate of the Notch1protein in the T-ALL was much higher than that in the B-ALL group (P<0.05).According to the ALL-LR, ALL-MR, ALL-HR, the positive expressionrates of the Notch1protein in the AL children were relatively increased, butthere was no significant difference obtained between the groups (P>0.05).[Conclusions]1. Expression patterns of Notch1are distinctive in different types ofchildren ALL, with the much higher level in T-ALL when compared to the levelof B-ALL.2. The deregulation of Notch1expression in children AML suggests that itmay play potential role during the pathogenesis.3. Similarly, an aberrant expression of Jagged1in children ALL and AMLis also indicative of its possible involvement during the pathogenesis of childrenAML.4. Given the expression levels of Notch1gene and Jagged1gene in bonemarrow and peripheral blood are consistent regardless of pathology, we may employ PB instead of BM for the examination of the expression level of thesetwo target genes.5. Further investigation of Notch1function is also of significance in theimmunophenotyping of children with AL.