Membrane Fc-IgG and C3b receptors on myeloid leukaemia cells: a comparison with cytoplasmic acid naphthyl acetate esterase cytochemistry

Daemonorops draco Blume Induces Apoptosis Against Acute Myeloid Leukemia Cells via Regulation of the miR-216b/c-Jun

Daemonorops draco Blume (DD), also called dragon’s blood, has been used as a traditional Korean medicine, especially for relieving pain caused by wound infection. Recently, it has been described that DD has antibacterial and analgesic effects. In this study, the underlying anticancer effect of DD associated with apoptosis was investigated in acute myeloid leukemia cell lines U937 and THP-1. DD exhibited cytotoxic effects and induced apoptosis in U937 and THP-1 cells. Moreover, DD treatment significantly reduced mitochondrial membrane potential (ΔΨ). The protein expression of cleaved poly(ADP-ribose) polymerase, cleaved caspase-3, p-H2A.X, CCAAT/enhancer-binding protein (CHOP), and activating transcription factor 4 was upregulated by DD treatment. Consistently, DD-treated cells had increased reactive oxygen species (ROS) level in a concentration-dependent manner via miR-216b activation in association with c-Jun inhibition. N-acetyl-L-cysteine pretreatment reversed the cytotoxic effect of DD treatment as well as prevented ROS accumulation. Collectively, the results of this study suggest that the anticancer effect of DD in AML was mediated by CHOP-dependent apoptosis along with ROS accumulation and included upregulation of miR-216b followed by a decrease in c-Jun.

Fcgamma receptor cross-linking stimulates cell proliferation of macrophages via the ERK pathway

Macrophage proliferation can be stimulated by phagocytosis and by cross-linking of Fcgamma receptors (FcgammaR). In this study, we investigated the role of FcgammaR and the signaling cascades that link FcgammaR activation to cell cycle progression. This effect was mediated by the activating FcgammaR, including FcgammaRI and III, via their Fcgamma subunit. Further investigation revealed that the cell cycle machinery was activated by FcgammaR cross-linking through downstream signaling events. Specifically, we identified the extracellular signal-regulated kinase (ERK) signaling pathway as a mediator of signals from FcgammaR activation to cyclin D1 expression, because cyclin D1 expression associated with FcgammaR cross-linking was attenuated by specific inhibitors of the ERK1/2 signaling pathway, PD98059 and U0126 and the spleen tyrosine kinase (Syk) inhibitor, Piceatannol. Our findings establish a link between the ERK activation and cell cycle signaling pathways, thus providing a causal mechanism by which FcgammaR activation produces a mitogenic effect that stimulates macrophage proliferation. Macrophage mitosis following FcgammaR activation could potentially affect the outcome of macrophage interactions with intracellular pathogens. In addition, our results suggest the possibility of new treatment options for certain infectious diseases, chronic inflammatory diseases, and leukemias based on interference with FcgammaR-stimulated macrophage cell proliferation.

Chronic myelocytic leukaemia: HLA association and decreased erythrocyte C3b receptor expression

A series of 27 adult patients with chronic myelocytic leukaemia (CML) were examined for erythrocyte C3b receptor (EC3bR) expression. Twenty-five patients were successfully HLA typed and there was a positive association of CML with HLA-B40 (P less than 0.01). Only 10 (37%) of the patients were EC3bR positive (P less than 0.00001) compared to 223 healthy controls of whom 198 (89%) were EC3bR positive. The positivity of EC3bR and HLA-B40 occurred simultaneously in six patients (P less than 0.05). HLA-B40 positivity and EC3bR expression were correlated with the following variables: age at the time of CML diagnoses, duration of CML (until death or the end of follow-up period 1 July 1983), the stage of CML and simultaneous medication. EC3bR positive patients were significantly more often in remission (P less than 0.05) and also had shorter duration of the disease (P less than 0.005) then did EC3bR negative ones. No significant correlation existed between EC3bR status and the other parameters. The presence of HLA-B40 did not associate with any of the listed variables. These findings may indicate the loss of the receptor in the course of CML with increasing immaturity of cells released from bone marrow.

Cytochemical and immunological characteristics of acute monocytic leukaemia

Immunological and cytochemical findings are presented from 12 cases of morphologically unequivocal acute monocytic leukaemia (AMoL). The results indicate considerable heterogeneity and three main non-morphological subgroups were identified. The blast cells from half the patients were positive for the presence of both cytoplasmic alpha naphthyl acetate esterase (ANAE) and monocyte-associated membrane determinants whereas the cells from three cases lacked detectable monocytic antigens despite the presence of strong cytochemical ANAE activity. A further three cases expressed monocytic antigens but were cytochemically unreactive for ANAE. These cytochemical results, which were extended by electrophoretic studies of ANAE isoenzymes, suggest that the absence of significant cytoplasmic ANAE activity does not preclude the diagnosis of AMoL and that serum lysozyme estimations may be of value in the recognition of immunocytochemically-atypical cases.

Cytochemical and electrophoretic characterisation of alpha naphthyl acetate esterases (ANAE) in acute myeloblastic leukaemia

The alpha naphthyl acetate esterase (ANAE) cytochemical staining patterns were examined in 40 cases of acute myeloblastic leukaemia (AML: FAB groups M1 and M2) classified by morphological and immunological criteria. The blast cells in most cases (62%) were ANAE-negative with the remainder showing diffuse, granular or focal reactions of varying intensity. The nature of cytoplasmic ANAE enzymes was further characterised in 20 cases by isoelectrophoretic analysis of ANAE isoenzymes. The results suggest that the presence of significant cytoplasmic ANAE reactivity in leukaemic myeloblasts is not due to the presence of monocyte-associated isoenzymes, in otherwise well-defined myeloblasts, but may reflect abnormally increased synthesis or atypical localisation of normally-occurring ANAE isoenzymes. In particular, the results of this study indicate the lack of discriminatory value of ANAE cytochemistry in the differentiation of AML from other acute leukaemias of non-monocytic type.