Expression and Significance of Leucine-rich Repeat-containing G-protein Coupled Receptor 5/6 in Wnt Pathway in Children with Acute Lymphoblastic Leukemia

Abstract

Objective To study the expression and significance of leucine-rich repeat-containing G-protein coupled receptor(LGR)5/6 in childhood acute lymphoblastic leukemia(ALL). Methods A total of 39 children who had ALL and achieved complete remission on day 33 after induction therapy were enrolled.The children before induction therapy were considered as the incipient group,and those who achieved complete remission on day 33 by induction therapy were considered as the remission group.According to the degree of risk,they were assigned into 3 groups:low-risk(n=16),intermediate-risk(n=9),and high-risk(n=14)groups.A total of 30 children with immune thrombocytopenia were taken as the control group.From each child in the incipient group,remission group,and control group,3 ml bone marrow sample was collected.Real-time fluorescent quantitative polymerase chain reaction was conducted to measure the mRNA expression of LGR5 and LGR6 in the blood cells of bone marrow.Western blot was employed to measure the protein expression of LGR5 and LGR6 in blood cells of bone marrow. Results Compared with the control(mRNA:1.541±0.409,protein:0.138±0.041)and remission(mRNA:1.418±0.324,protein:0.130±0.033)groups,the incipient group had significantly lower mRNA(0.850±0.279)and protein(0.083±0.027)expression of LGR5(PmRNA=0.000,Pprotein=0.000).Compared with the control(mRNA:0.928±0.373,protein:0.094±0.037)and remission(mRNA:0.886±0.390,protein:0.111±0.039)groups,the incipient group had significantly higher mRNA(2.444±1.160)and protein(0.298±0.088)expression of LGR6(PmRNA=0.000,Pprotein=0.000).In the incipient groups,low-risk children showed significantly higher mRNA(1.004±0.284)and protein(0.097±0.030)expression of LGR5 than the intermediate-risk children(mRNA:0.728±0.239,protein:0.071±0.022)and high-risk children(mRNA:0.752±0.222,protein:0.074±0.020)(PmRNA=0.012,Pprotein=0.016);low-risk children showed significantly lower mRNA(1.822±0.979)and protein(0.245±0.077)expression of LGR6 than the intermediate-risk children(mRNA:2.954±1.039,protein:0.338±0.081)and high-risk children(mRNA:2.827±1.165,protein:0.333±0.075)(PmRNA=0.016,Pprotein=0.004).In the remission groups,low-risk children showed significantly higher mRNA(1.597±0.329)and protein(0.150±0.035)expression of LGR5 than the intermediate-risk children(mRNA:1.277±0.288,protein:0.117±0.029)and high-risk children(mRNA:1.305±0.253,protein:0.116±0.023)(PmRNA=0.012,Pprotein=0.006);low-risk children showed significantly lower mRNA(0.662±0.334)and protein(0.089±0.034)expression of LGR6 than the intermediate-risk children(mRNA:1.066±0.273,protein:0.130±0.033)and high-risk children(mRNA:1.027±0.405,protein:0.126±0.038)(PmRNA=0.007,Pprotein=0.007). Conclusion The expression of LGR5 and LGR6 are closely related to the occurrence and risk of childhood ALL,but its mechanism needs further study.