[Expression and Significance of Low-Density Lipoprotein-Related Receptors 5 and 6 in the Wnt/β-Catenin Signaling Pathway in Childhood Acute Lymphoblastic Leukemia]

Abstract

Objective: To investigate the significance of low-density lipoprotein receptor-related protein 5 and 6 (LRP5/6) in the Wnt/β-catenin signaling pathway in the pathogenesis and prognosis of childhood acute lymphoblastic leukemia (ALL).

Methods: A total of 43 children who were newly diagnosed and achieved complete remission after remission induction therapy were enrolled. The children before treatment were included in incipient group, and after treatment when achieved complete remission included in remission group. A total of 39 children with immune thrombocytopenia were enrolled in control group. Three milliliter bone marrow samples were collected from above-mentioned each group. QRT-PCR was used to determine the mRNA expression of LRP5 and LRP6 in blood mononuclear cells of bone marrow. Western blot was used to detect the protein expression of LRP5 and LRP6. According to the protein expression levels of LRP5 and LRP6, the children were divided into low-expression group and high-expression group, and the clinical biological characteristics were compared between these two groups. Survival analysis was performed by Kaplan-Meier method.

Results: Both mRNA and protein expression levels of LRP5 and 6 were upregulated in the incipient group compared with the control and remission group (P<0.05). The mRNA and protein expressions of LRP5 and LRP6 in the high-risk group were higher than those in the medium-risk group (P<0.05), it is the same as in the medium-risk group than the low-risk group (P<0.05). The mRNA and protein expressions of LRP5 and 6 positively correlated with risk degree in the incipient group (r_{LRP5 mRNA}=0.84, P<0.05; r_{LRP6 mRNA}=0.66, P<0.05; r_{LRP5 protein}=0.82, P<0.05; r_{LRP6 protein}=0.76, P<0.05). The white blood cell count and lactate dehydrogenase in LRP5 and LRP6 high expression group were significantly higher than those in low expression group (P<0.05), while there was no significant difference in other biological characteristics. Kaplan-meier survival analysis showed that in the 43 children 3-year overall survival rate and event-free survival rate was (91.7±4.7)% and (87.6±5.2)%, respectively.

Conclusion: The high expression of LRP5/6 may be one of the pathogenesis of childhood ALL, and the degree of LRP5/6 increase may be related to the risk level.