The Role Of MXRA7 In The Development Of Acute B-cell Lymphocytic Leukemia

Objective:Matrix remodeling associated gene 7(MXRA7),which was firstly named in 2003,is a member of the matrix remodeling associated gene family.Our group have demonstrated MXRA7 was involved in some critical physiological and pathological processes,such as tissue repairing and cell differentiation.We have found that MXRA7 play a role in the development of acute promyelocytic leukemia.MXRA7 has a higher expression in acute B-lymphoblastic leukemia(B-ALL)patients’ bone marrow cells than Healthy people’s reveal by public databases,suggesting that MXRA7 may play a role in the development of B-ALL.Thus,REH and 697 cell lines were used for exploring the function and mechanism of MXRA7 in B-ALL.Methods:(1)Bloodspot database and Leukemia Gene Atlas(LGA)database were used to analyze the expression of MXRA7 in B-ALL.(2)Detect the expression of MXRA7 in the bone marrow cells of B-ALL patients,and normal healthy donors,and in B-ALL cell lines by Real-time quantitative PCR(Real-time qPCR)and Western blot.(3)Stably MXRA7-knockdown cell lines were constructed using lentivirus,and MXRA7 expression lecel was proved by Real-time qPCR and Western blot.(4)The cell proliferation was detected by cell viability,using CCK8 method,and cell cycle distribution,using flow cytometry.(5)The Transwell assay was used to detect cell invasion ability.And the expression of Matrix metalloproteinases was detected by Real-time qPCR.(6)Drugs resistance induced by AraC and Daunorubicin in transfected cell lines was detected using cell apoptosis assay.(7)The expression of CD38 on the surface of transfected cell lines was detected with flow cytometry.Results:(1)The analysis of databases revealed MXRA7 has a higher expression in B-ALL,especially in precursor B acute lymphoblastic leukemia(BCP-ALL).(2)The mRNA and protein of MXRA7 had a higher expression in B-ALL patients than in the normal donors.(3)Stably transfected cell lines with GFP protein were established by sorting with flow cytometer.The results of Real-time qPCR and Western Blot assays verified the MXRA7-knockdown cell lines were successfully constructed.(4)Knockdown of MXRA7 increased the cell viability of REH cell line,while,MXRA7 did not significantly affect 697 cell line.MXRA7 has no effect on the cell cycle of both cell lines.(5)The invasion ability of REH cells was not affected by knockdown of MXRA7,and the expression of MMP-2,MMP-8 and MMP-9 changed inconsistently.The invasion ability of 697 cells showed a decreasing trend after knockdown of MXRA7,and the expressions of MMP-2,MMP-8 and MMP-9 were decreased.(6)Knockdown of MXRA7 increased the percentages of cell apoptosis in both REH and 697 cells treated with chemotherapy drugs,AraC and daunorubicin.The activity of apoptotic protein,Caspase3/8/9,was also increased by knockdown of MXRA7.(7)Knockdown of MXRA7 decreased the expression of CD38 on the cell surface of 697 cell,but not in REH cells.Discussion:In conclusion,this study demonstrated that MXRA7 is highly expresses in Acute B-lymphoblastic leukemia,and also can influence the drug resistance of B-ALL cells via regulating the expression of apoptotic proteins.Moreover.it can affect the expression of CD38 which related to the poor prognosis of B-ALL.It suggest the expression of MXRA7 in B-ALL patients may be a factors of refractory acute B-lymphocytic leukemia.