Bone marrow infiltrated natural killer cells predicted the anti-leukemia activity of MCL1 or BCL2 inhibitors in acute myeloid leukemia.

Acute myeloid leukemia (AML) is still incurable due to its heterogeneity and complexity of tumor microenvironment. It is imperative therefore to understand the molecular pathogenesis of AML and identify leukemia-associated biomarkers to formulate effective treatment strategies. Here, we systematically analyzed the clinical characters and natural killer (NK) cells portion in seventy newly-diagnosis (ND) AML patients. We found that the proportion of NK cells in the bone marrow of ND-AML patients could predict the prognosis of patients by analyzing the types and expression abundance of NK related ligands in tumor cells. Furthermore, MCL1 inhibitor but not BCL2 inhibitor combined with NK cell-based immunotherapy could effectively improve the therapeutic efficiency via inhibiting proliferation and inducing apoptosis of AML primary cells as well as cell lines in vitro. There results provide valuable insights that could help for exploring new therapeutic strategies for leukemia treatment.

PALLD Regulates Phagocytosis by Enabling Timely Actin Polymerization and Depolymerization.

PALLD is an actin cross-linker supporting cellular mechanical tension. However, its involvement in the regulation of phagocytosis, a cellular activity essential for innate immunity and physiological tissue turnover, is unclear. We report that PALLD is highly induced along with all-trans-retinoic acid-induced maturation of myeloid leukemia cells, to promote Ig- or complement-opsonized phagocytosis. PALLD mechanistically facilitates phagocytic receptor clustering by regulating actin polymerization and c-Src dynamic activation during particle binding and early phagosome formation. PALLD is also required at the nascent phagosome to recruit phosphatase oculocerebrorenal syndrome of Lowe, which regulates phosphatidylinositol-4,5-bisphosphate hydrolysis and actin depolymerization to complete phagosome closure. Collectively, our results show a new function for PALLD as a crucial regulator of the early phase of phagocytosis by elaborating dynamic actin polymerization and depolymerization.

MiR-103 regulates the angiogenesis of ischemic stroke rats by targeting vascular endothelial growth factor (VEGF).

OBJECTIVES: To investigate the effect of miR-103 on the angiogenesis of ischemic stroke rats via targeting vascular endothelial growth factor (VEGF) at the molecular level. MATERIALS AND METHODS: Rat models had received the middle cerebral artery occlusion (MCAO) or sham operation before grouping, and cell models of oxygen-glucose deprivation (OGD) were performed. FITC-dextran, matrigel, and Trans-well assays were used to evaluate the vascular density, tube formation, and cell migration respectively. The expression levels of miR-103 and VEGF were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. Dual-luciferase assay was used for analyzing the targeting relationship between miR-103 and VEGF. RESULTS: We found the reduced miR-103 in rats after MCAO. Down-regulating miR-103 with the miR-103 inhibitor enhanced VEGF, ameliorated the neurological scores, decreased infarct volume, and increased vascular density in rats after MCAO. Besides, in OGD human umbilical vein endothelial cells (HUVECs), inhibition of miR-103 could promote the increase of tube length and the migration of cells. Additionally, we found that miR-103 could directly target VEGF and thereby lead to the down-expression of VEGF. Meanwhile, si-VEGF could reverse the effect of miR-103 inhibitor on angiogenesis in rats subjected to MCAO. CONCLUSION: Inhibition of miR-103 could promote ischemic stroke angiogenesis and reduce infarction volume via enhancing VEGF, which provides a new target for the clinical treatment of ischemic stroke.

[Analysis of CEBPA mutation in acute myeloid leukemia].

In order to evaluate the incidence of CCAAT/enhancer binding protein alpha (cebpa) gene mutation in patients with acute myeloid leukemia (AML), 22 AML patients with normal karyotype (NK-AML) were enrolled in this study, including de novo AML and relapsed AML. The cebpa gene was amplified by 2 stages using genomic DNA as template, the cebpa gene mutation amplified product was detected by direct sequencing or clone sequencing. The results showed that the cebpa mutations including deletion and insertion were found in 4 out of 22 AML patients (18.2%) and all of these 4 patients were M(2). Two patients had N-terminal nonsense mutation and the other two had C-terminal in-frame mutation. It is concluded that PCR combined with direct sequencing and clone sequencing can be used to detect cebpa mutations. cebpa mutations are mainly identified in M(2) subtype of NK-AML patients, its significance for prognosis needs to further investigate.

[Immunophenotypic features in 143 cases of acute promyelocytic leukemia].

This study was aimed to investigate the immunophenotypic characteristics of acute promyelocytic leukemia (APL). CD45/Side Scatter (SSC) gating strategy and multiparametric flow cytometry were used to determine immunophenotype of 143 patients with APL. The immunophenotypic features were compared between newly diagnosed APL patients and relapsed APL patients. 42 patients with HLA-DR(-) (non-APL AML, DR(-)AML) were randomly selected as controls. 31 out of 42 AML patients were CD34 negative, and their immunophenotypes were compared with those in newly diagnosed APL patients. The results showed that (1) CD34 and HLA-DR were both negative in 91.9% of newly diagnosed APL, while the positive rate of CD34 and HLA-DR elevated in relapsed cases (3.0% vs 37.5%, 3.9% vs 37.5%). The positive rate of CD34 in HLA-DR(-) AML group was higher than that in newly diagnosed APL group (23.4% vs 3.0%). The positive level of CD34 in newly diagnosed APL group was lower than that in HLA-DR(-) AML group; (2) the positive rate of CD33 in newly diagnosed APL group was higher than that in other groups (97.0% vs 75.0%, 83.3%, 83.9%), as well as the the positive level of CD33 (p < 0.05). (3) no lymphoid antigen other than CD2 was expressed in newly diagnosed APL group. The positive rate of CD7 was 9.5% in DR(-) AML group and 6.5% in CD34(-)/DR(-) AML group, both were higher than those of newly diagnosed APL group (p < 0.05). It is concluded that the immunophenotyping can provide proof to the rapid diagnosis of APL. For those patients with DR(-) AML, it may be helpful to identify APL depending on following features: low or negative CD34 expression, homogeneous and bright expression of CD33, no lymphoid antigens other than CD2, higher SSC.