Expression Of CAS In Bone Marrow Of Patients With Acute Promyelocytic Leukemia And Its Effect On Cell Proliferation

Objective:To investigate the expression of apoptosis-prone protein(CAS)in bone marrow of patients with acute promyelocytic leukemia and its effect on cell proliferation.Methods:(1)Bone marrow tissues of patients with acute myeloid leukemia(AML)were stained with CAS by immunohistochemical method to determine the location of CAS in leukemia cells.(2)Bone marrow fluid specimens and related clinical data were collected from 7 newly diagnosed patients with acute promyelocytic leukemia and 11 patients with benign hematologic diseases.All patients were confirmed by bone marrow cytology,immunology,cytogenetics and molecμlar genetics.The expression of CAS in bone marrow was detected by flow cytometry.SPSS25.0 software was used to analyze the expression of CAS in patients with acute promyelocytic leukemia.(3)The expression of CAS in human promyelocytic leukemia cell line NB4 was silenced by lentivirus,and the silencing effect was verified by Western blot.(4)CCK-8 cell assay were used to investigate the effects of CAS on cell proliferation,and the cell cycle was detected by flow cytometry.Resμlts:(1)Immunohistochemical resμlts showed that CAS was mainly located in cytoplasm in leukemia cells.(2)Flow cytometry showed that the expression of CAS in patients with acute promyelocytic leukemia was higher than that in patients with benign hematopathy,and there was a statistical difference between the two groups(P < 0.05).When the critical value was 58.4%,the area under ROC curve(AUC)for CAS to distinguish APL from benign hematopathy was 0.896(95%CI: 0.75～1,P =0.006),sensitivity 85.7%,specificity 81.8%.(3)Western blot resμlts showed that CAS silencing effect was significant in NB4 cells mediated by lentivirus.(4)CCK-8 resμlts showed that silencing CAS expression in NB4 cells inhibited the proliferation of human acute promyelocytic leukemia cells,the cells were arrested in G1 phase.Conclusion:(1)CAS is mainly located in the cytoplasm of leukemia cells,and its expression level is higher than that of patients with benign hematologic diseases.(2)Silencing CAS may inhibit the proliferation of human promyelocytic leukemia cells through cell cycle arrest.