The Expression And Significance Of Nr4a1 In Patients With Acute Leukemia And Its Relationship With Caspase-3

Backgroud and ObjectiveAcute leukemia is a highly heterogeneous human malignancy, presumably reflecting specific molecular alterations in gene expression and protein activity that are thought to underlie the variable disease outcome. The acute leukmeias are clonal malingnance of hematopietic stem cells that are Characterized by the excessive Porlierfation,dysdifferentiation and the inhibition of paoptosis. The activation of oncogenes or inactivation of tumour suppressor genes plays a cnetral role in the pathogenesis of malingnant diseases.NR4A1 is an immediate-early response gene and an orphan member of the steroid/thyroid/retinoid receptor superfamily. The orphan receptor NR4A1 functions in the nucleus as a transcription factor to negatively or positively regulate gene expression.Recently, NR4A1 has been regard as an important anti-oncogene in tumorigenesis.The study of that demonstrate abrogation of nuclear receptors NR4A1 leads to development of acute myeloid leukemia.The abrogation of NR4A1 plays important roles in AL. NR4A1 can decreased expression of the AP-1 transcription factors JunB and c-Jun and defective extrinsic apoptotic (Fas-L and TRAIL) signaling. The NR4A1 initiates apoptosis largely by translocating from the nucleus to the mitochondria, causing the release of cytochrome c. The translocated NR4A1 interacted with ER-targeting Bcl-2 and conformationally converts it to a killer that triggers cytochrome c release and apoptosis.The study demonstrate that abnormal expression of NR4A1 and caspase-3 in tumor.The abrogation of NR4A1 and caspase-3 contributing to leukemogenesis.To explore the expression of NR4A1 and its relationship with caspase-3 in acute leukemia, the expression of NR4A1 and caspase-3 in bone marrow mononuclear cells from untreated acute leukemia patients, AL-CR patients and control group were detected by immunocytochemical staining (S-P three method). Their function in the leukemogenesis was further discussed.Materials and method1. Patients: (1) De novo leukemia group : Samples from 49 cases of de novo acute leukemia were collected. Patients were 17-73 years(mean 42 years old) with 30 males and 19 females. The whole patients were divided into two groups:①Acute Myelogenous Leukemia (n=31),including Mo1 cases, M₁1 cases, M₂ 19 cases, M₃ 4 cases, M₄ 2 cases, M₅ 4 cases;t (8; 21) (q22; q22); AML-ETO 6 cases, t (15; 17) (q23; q21); PML-RAR a 3 cases, t (16; 16) (p13; q22) or inv (16) (p13; q22), (CBFβ/MYH11) 2 cases and others category 8 cases , normalcategory 3 cases ,not done detect 9 cases were contained.②Acute Lymphocytic Leukemia (n=18);The acute leukemia were diagnosed by cell morphology,histological chemistry,cellular immunology and (or) molecular genetics(2) AL-CR group: bone marrow samples from patients (n=29) who reached CR after chemotherapy. It was further divided into AML-CR and ALL-CR. (3) The control group : bone marrow samples from non-maligant hematologic diseases (n=12).All the samples were obtained from the patients treated in the Hemologic Department of the First Affiliated Hospital of Zhengzhou University through August of 2008 to February of 2009.2.Sample processing: bone marrow mononuclear cells were separated from 1ml bone marrow of untreated Acute Leukemia patients and control patients. The BMNC were load on slides and detected by immunocytochemcal staining(S-P three-step method) for the expression of NR4A1 and caspase-3.3. Statistical analysis:The data were analyzed with Fisher's exact test and Spearman correlation by SPSS11.0 and the standard of statistic significance was established as a=0.05.Results1. In aucte luekmeia, the expression of NR4A1 was singificantly lower than that in AL-CR and in nomral control.The positive rate of NR4A1 in AL-CR was 75.86%. The positive rate of NR4A1 in nomral control was83.33%, The expression of NR4A1 was no singificance with AL-CR and nomral control (P>0.05). The positive rate of NR4A1 in AL was 18.36%, with 16.13% in AML,22.22% in ALL. There was no singificance with AML and ALL, (P>0.05 ).The expression of NR4A1 in AL was singificantly lower than that in AL-CR and control(P<0.005).2. In aucte luekmeia, the expression of caspase-3 was singificantly lower than that in AL-CR and in nomral control.The positive rate of caspase-3 in AL-CR was 72.41%. The positive rate of caspase-3 in nomral control was 75.00%, The expression of caspase-3 was no singificance with AL-CR and nomral control(P>0.05) .The positive rate of caspase-3 in AL was 26.53%,with 25.81% in AML,27.78% in ALL. There was no singificance with AML and ALL,(P>0.05) .The expression of NR4A1 in AL was singificantly lower than that in AL-CR and control(P<0.05).2. There was positive relations bewteen the NR4A1 and caspase-3 experssion in all cases and the correlation coefficient was 0.8033. The expression of NR4A1 was no relationship with patients'olds,sex and reproduction quality abnormal genetics in acute lekumeia (P>0.05) . The decrease level of NR4A1 had a positive Correlation with hihg blood white cell count and metastasis out of bone marrow. (P<0.05) Conclusion1. In aucte luekmeia, the expression of NR4A1 was singificantly lower than That in AL-CR and in nomral control, Our study demonstrate that the abrogation of nuclear receptors Nr4a1 leads to development of acute myeloid leukemia2. The decrease level of NR4A1 had a positive Correlation with hihg blood white cell count and metastasis out of bone marrow. Our study demonstrate that the abrogation of nuclear receptors Nr4a1 was relationship with AL cells proliferation and metastasis out of bone marrow.3. There was positive relations bewteen the NR4A1 and caspase-3 experssion in AL. Demonstrate that abrogation of caspase-3 and Nr4a1 contributing to leukemogenesis.4. Downregulation of NR4A1 was a common feature in human AL patients, irrespective of karyotype.