tretinoin and bufalin

To investigate changes in the adherent ability, the expression of adhesion related proteins Pyk2 and paxillin during HL-60 cells differentiation into granulocyte-monocyte induced by low-dose (LD) bufalin in combination with all-trans retinoic acid (ATRA), and to explore the effects of bortezomib on cellular adhesion and the expression of Pyk2 and paxillin.. The expression of CD11b was detected by flow cytometry, cellular adherence ability by MTT assay, and the expressions of Pyk2, paxillin and tubulin by Western blot.. The combination of 5 nmol/L bufalin and 30 nmol/L ATRA induced HL-60 cells differentiation in a time-dependent manner, the percentages of CD11b positive cells treated for 2 d and 4 d being (20.0 +/- 2.8)% and (75.0 +/- 5.3)%, respectively, with the increasing of cellular adherence ability. Meanwhile the expressions of Pyk2 and Paxillin were also up-regulated in a time-dependent manner. Bortezomib suppressed HL-60 cell adhesion in a dose-dependent manner. At concentrations of 1 nmol/L and 10 nmol/L the adherence level were (7.8 +/- 0.1)% and (5.3 +/- 0.3)%, respectively, with down-regulation of Pyk2 but not Paxillin.. Pyk2 is involved in the regulation of cellular adherence function. Bortezomib might inhibit HL-60 cells adhension function by down-regulation of Pyk2 expression.

Topics: Boronic Acids; Bortezomib; Bufanolides; Cell Adhesion; Cell Proliferation; Focal Adhesion Kinase 2; HL-60 Cells; Humans; Paxillin; Pyrazines; Tretinoin

The Casitas B-lineage Lymphoma (Cbl) family of ubiquitin ligases is multifunctional proteins that play important roles in different cell signaling pathways. It has been reported that c-Cbl and Cbl-b mRNAs are up-regulated during TPA-induced U937 and HL-60 cell differentiation. But the mechanism of the up-regulation and the roles of the Cbl family of ubiquitin ligases still remain unclear. In the present study, we demonstrated that bufalin enhanced all-trans retinoic acid (ATRA) induced differentiation of HL-60 cells, accompanied by up-regulation of the Cbl family of ubiquitin ligases. CsA, an inhibitor of calcium mobilization, reversed this up-regulation. Pretreatment with CsA and PS-341 did not affect the expression of CD11b, but suppressed the percentage of adherent cells. Lipid raft localization of Cbl-b enhanced cell adhesion, while C-terminal deletion partially suppressed the effect. Moreover, the expression of the adhesion-related kinases Pyk2 and Paxillin was up-regulated in parallel with the increase of Cbl proteins. These results suggested that up-regulation of c-Cbl and Cbl-b was involved in the regulation of ATRA and bufalin-induced HL-60 cell adhesion rather than cell differentiation, which might be mediated by lipid raft localization, ubiquitin ligase activity and C-terminal structure of Cbl proteins. Meanwhile, up-regulation of proline-rich tyrosine kinase (Pyk2) and Paxillin might also be implicated in this regulation.

Topics: Antineoplastic Agents; Bufanolides; Cell Adhesion; Cell Differentiation; Cells, Cultured; HL-60 Cells; Humans; Paxillin; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-cbl; Tretinoin; Ubiquitin-Protein Ligases; Up-Regulation

To investigate the effect of bufalin combined with all-trans retinoic acid-induced (ATRA) differentiation of acute promyelocytic leukemia (APL) cells in primary culture.. Fresh leukemia cells were obtained from heparinized bone marrow aspirations of 12 newly diagnosed APL patients. Cell viability was determined by trypan blue dye exclusion. Apoptosis of APL cell was assessed by morphological analysis. Differentiation of APL cell was also assessed by morphological analysis. Nitro blue tetrazolium (NBT) reduction test and expression of the granulocyte/macrophage-specific antigen CD(11)b was carried out with flow cytometric assay.. Bufalin combined with ATRA can induce differentiation of APL cells towards mature stages, NBT reduction was increased 15% - 52% and CD(11)b expression was also increased 16% - 69% in combination of bufalin and ATRA as compared with that of ATRA alone, while the concentration of ATRA needed in the combination group was reduced to 30% and the time of differentiation was reduced from 7 days to 4 days.. The combination of ATRA with bufalin can significantly enhance the differentiation of acute promyelocytic leukemia cells in primary culture by ATRA.

Topics: Antineoplastic Agents; Apoptosis; Bone Marrow Cells; Bufanolides; Cell Differentiation; Cell Line, Tumor; Drug Synergism; Flow Cytometry; Humans; Leukemia, Promyelocytic, Acute; Tretinoin

Bufalin, a cardiotonic steroid isolated from the Chinese toad venom preparation Chan'su, has differentiation-inducing activity in several myeloid leukemia cell lines. We examined the effect of bufalin on differentiation of leukemic cells from acute myeloid leukemia (AML) patients in primary culture. Bufalin significantly stimulated functional and morphologic differentiation of leukemia cells in four of 20 cases, suggesting that bufalin alone is only a modest inducer of differentiation of AML cells in primary culture. In contrast, acute promyelocytic leukemia (APL) cells showed synergistic differentiation after treatment with all-trans retinoic acid (RA) and bufalin. In some cases, bufalin restored RA sensitivity to previously resistant APL cells. The effective concentration of bufalin for differentiation-inducing activity in APL cells was lower than for its cardiac action. Combined treatment with bufalin and RA may be more effective than RA alone in differentiation therapy of APL.

Topics: Acute Disease; Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Bufanolides; Cardiotonic Agents; Cell Differentiation; Drug Resistance, Neoplasm; Drug Synergism; Female; Humans; Leukemia, Myeloid; Leukemia, Promyelocytic, Acute; Male; Middle Aged; Tretinoin; Tumor Cells, Cultured

The extreme host specificity of pathogenic neisseriae limits investigations aimed at the analysis of bacterial-host interactions almost completely to the use of in vitro models. Although permanent epithelial and endothelial cell lines are already indispensable tools with respect to initial infection processes, studies concerning the interaction of neisseriae with phagocytic cells have been confined to primary human blood cells. We investigated the use of human leukemia-derived monocytic and myelomonocytic cell lines that can be differentiated in vitro towards phagocytic cells by a panel of chemical and biological reagents including cytokines, vitamin analogs, and antileukemia drugs. Whereas tumor necrosis factor alpha, gamma interferon, bufalin, or granulocyte-macrophage colony-stimulating factor only marginally increased the ability of monocytic MonoMac-6 and myelomonocytic JOSK-M cells to interact with the bacteria, retinoic acid and vitamin D3 treatment for 2 to 4 days led to highly phagocytic cells that internalized gonococci in an Opa protein-specific manner. This is comparable to the phagocytosis by primary monocytes from human blood, where more than 80% of cells are infected with intracellular bacteria. The increased phagocytic activity of JOSK-M cells following in vitro differentiation was paralleled by enhanced oxidative burst capacity. Whereas undifferentiated cells responded to neither phorbol 12-myristate 13-acetate nor other known soluble and particulate stimuli, cells incubated with retinoic acid and bufalin showed the same pattern and the same intensity of oxidative burst activity in response to Neisseria gonorrhoeae as primary cells: Opa-expressing gonococci elicited an oxidative burst, whereas Opa- gonococci did not. The surface expression of major histocompatibility complex (MHC) class II molecules was only slightly changed after retinoic acid treatment. Also, phagocytosis of gonococci had no influence on MHC class II surface expression. Taken together, our results demonstrate that in vitro-differentiated human myelomonocytic JOSK-M cells provide a suitable model for the study of a variety of aspects of the gonococcal interaction with phagocytes.

Topics: Adult; Antibodies, Monoclonal; Antigens, Bacterial; Bufanolides; Cell Differentiation; Cells, Cultured; Cholecalciferol; Flow Cytometry; Fluorescent Antibody Technique, Indirect; Gonorrhea; Granulocyte-Macrophage Colony-Stimulating Factor; Histocompatibility Antigens Class II; HLA-DR Antigens; Humans; Interferon-gamma; Leukocytes, Mononuclear; Monocytes; Neisseria gonorrhoeae; Phagocytosis; Respiratory Burst; Tetradecanoylphorbol Acetate; Tretinoin; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha

When human leukemia HL-60 cells were treated with 10(-7) M bufalin, the amounts of both topoisomerase (topo) II alpha and II beta and the activity of topo II decreased markedly and were almost undetectable 18 h after the start of treatment. The level of topo II mRNA started to decrease immediately after the start of treatment with bufalin, with a subsequent decrease in the amount of topo II alpha protein. These changes preceded the fragmentation of DNA, a typical feature of apoptosis. The results suggest that bufalin caused a marked decrease in the steady-state level of topo II alpha mRNA, which led to a decrease in the amount and activity of the enzyme and to the induction of apoptosis. A reduction in the level of topo II alpha by bufalin was also observed in other lines of human leukemia cells such as ML1 and U937. The results were exploited to potentiate the effects of cisplatin and retinoic acid (RA) on HL-60 cells: pretreatment of HL-60 cells with 10(-7) M bufalin for 6 h increased the inhibitory effects of cisplatin and RA on cell growth and enhanced the induction of cell death.

Topics: Antineoplastic Agents; Apoptosis; Bufanolides; Cisplatin; DNA Fragmentation; DNA Topoisomerases, Type II; DNA, Neoplasm; Drug Synergism; Enzyme Induction; Enzyme Inhibitors; HL-60 Cells; Humans; Isoenzymes; Neoplasm Proteins; RNA, Messenger; RNA, Neoplasm; Tetradecanoylphorbol Acetate; Topoisomerase II Inhibitors; Tretinoin