Induced Apoptosis In HL-60 Cells Research Articles

Rapamycin induces human acute promyelocytic leukemia cell HL-60 autophagic apoptosis.

We aimed at investigating the effects of rapamycin on apoptosis and autophagy of human acute promyelocytic leukemia cell line HL-60, and to preliminarily explore the mechanism of extra medullary infiltration of leukemia cells with human acute promyelocytic leukemia cell line HL-60 as the object of study, providing a theoretical basis for the clinical treatment of leukemia. After HL-60 cells were cultured in vitro, the effect of rapamycin on proliferation ability of HL-60 cells was determined by methyl thiazolyl tetrazolium (MTT) method, the cell apoptosis ratio was detected by flow cytometer, the change of autophagy after HL-60 cells acted by rapamycin was tested by monodansylcadaverine (MDC) fluorescence staining, the mRNA expression of autophagy-related molecule was detected by polymerase chain reaction (PCR), and the expressions of apoptosis-related protein and autophagy-related protein were determined by Western blotting (WB). HL-60 cell proliferation could be significantly inhibited by rapamycin (80 μg/mL-640 μg/mL), which was in a dose-dependent manner. HL-60 cell apoptosis ratio and apoptosis-related protein expression were distinctly improved by rapamycin. Cell autophagy level, mRNA expression of autophagy-related molecule and autophagy-related protein expression were remarkably induced by rapamycin. Rapamycin can induce HL-60 cell apoptosis, which is produced mainly by inducing cell autophagy.

Design and synthesis of novel nitrogen mustard-evodiamine hybrids with selective antiproliferative activity

A series of novel nitrogen mustard-evodiamine hybrids were synthesized and evaluated for their antitproliferative properties. The antiproliferative activities of 10a–d, 11a–d, and 12a–d against four different kinds of human cancer cell lines (PC-3, HepG2, THP-1 and HL-60) and human normal peripheral blood mononuclear cells (PBMC) were determined. The results showed that all the target hybrid compounds exhibited antiproliferative activities against tested human tumor cell lines to some extent and no antiproliferative activities (>200 μM) against human normal PBMC cells. The antiproliferative selectivity between tumorous and normal cells was very useful for further antitumor drug development. Among the target compounds, 12c showed the strongest cytotoxicity against two tumor cell lines (THP-1 and HL-60) with IC50 values of 4.05 μM and 0.50 μM, respectively, and selected for further mechanism study in HL-60 cells. The results showed that 12c could induce HL-60 cells apoptosis and arrest at G2 phase at low sub-micromolar concentrations via mitochondria-related pathways.

Flavichalasines A\u2013M, cytochalasan alkaloids from Aspergillus flavipes

Two new tetracyclic cytochalasans, flavichalasines A and B (1 and 2), three new pentacyclic cytochalasans, flavichalasines C–E (3–5), and eight new tricyclic cytochalasans, flavichalasines F–M (6–13), together with eight known analogues (14–21), were isolated from the solid culture of Aspergillus flavipes. Structures of these new compounds were elucidated on the basis of extensive spectroscopic analyses including 1D, 2D NMR and HRESIMS data. Their absolute configurations were determined by comparison of their experimental ECD with either computed ECD or experimental ECD spectrum of known compound. The structure and absolute configuration of 2 were further determined by X-ray crystallographic diffraction. Flavichalasine A (1) represents the first example of cytochalasan with a terminal double bond at the macrocyclic ring and flavichalasine E (5) is the only cytochalasan with an α-oriented oxygen-bridge in D ring. These new compounds were evaluated for their cytotoxic activities against seven human cancer cell lines, of which, 6 and 14 displayed moderate inhibitory activities against tested cell lines. In addition, compounds 6 and 14 induced apoptosis of HL60 cells by activation of caspase-3 and degradation of PARP.

Targeting miR-155 suppresses proliferation and induces apoptosis of HL-60 cells by targeting Slug/PUMA signal.

Recent studies have shown that high miR-155 expression was associated with poor prognosis in patients with acute myelogeneous leukemia (AML). Furthermore, targeting miR-155 results in monocytic differentiation and apoptosis. However, the exact role and mechanisms of miR-155 in human AML remains speculative. HL-60 cells were treated with anti-miR-155 for 72 h. Cell growth and apoptosis in vitro were detected by MTT, BrdU proliferation, colony formation and flow cytometry assay. The effect of anti-miR-155 on growth of HL-60 cells was also evaluated in a leukemia mouse model. Slug cDNA and PUMA siRNA trannsfection was used to assess the signal pathway. Different protein expression was detected by western blot assay and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) assay. The results shown that targeting miR-155 resulted in a 24-fold decrease of miR-155 expression compared to negative control in the HL-60 cells. Targeting miR-155 significantly downregulated Slug and upregulated PUMA expression, and decreased HL-60 cell growth by 70% , impaired colony formation by approximately 60%, and increased HL-60 cell apoptosis by 45%. Targeting PUMA reversed miR-155 sliencing-induced proliferation and apoptosis of HL-60 cells. Restoration of Slug decreased PUMA expression. In murine engraftment models of HL-60 cells, we showed that targeting miR-155 was able to reduce tumor growth. This was accompanied with decreased Slug expression and increased PUMA expression in these tumors. Collectively, our findings strongly suggest targeting miR-155 exhibited in vivo and in vitro antileukemic activities in AML through a novel mechanism resulting in inhibition of Slug expression and increase of PUMA expression.

Pure total flavonoids from Citrus paradisi Macfad induce leukemia cell apoptosis in vitro.

To investigate the potential effect of pure total flavonoids from Citrus paradisi Macfad peel (PTFC) on the proliferation of human myeloid leukemia cells Kasumi-1, HL-60 and K562, and the underlying mechanisms. PTFC was extracted from Citrus paradisi Macfad peel and was identified by high performance liquid chromatography. The effect of PTFC on the proliferation and apoptosis of leukemia cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, fluorescent microscopy and flow cytometry, respectively. The effect of PTFC on the expression levels of apoptosis-related regulators was determined by Western blot assay. Treatment with PTFC inhibited leukemia cell proliferation in a dose- and time-dependent manner and triggered Kasumi-1 cell apoptosis. Treatment with PTFC significantly increased the levels of activated poly adenosine diphosphate-ribosepolymerase and caspase-3/-9, but reduced the levels of Mcl-1 expression in Kasumi-1 cells. However, PTFC did not obviously induce HL-60 cell apoptosis. PTFC inhibited leukemia cell proliferation and induced their apoptosis by modulating apoptosisrelated regulator expression in leukemia cells in vitro.

A Standardized Chemically Modified Curcuma longa Extract Modulates IRAK-MAPK Signaling in Inflammation and Potentiates Cytotoxicity.

The TLR/IL-1R pathway is a critical signaling module that is misregulated in pathologies like inflammation and cancer. Extracts from turmeric (Curcuma longa L.) enriched in curcumin and carbonyls like turmerones have been shown to exert potent anti-inflammatory effects. The present study evaluated the anti-inflammatory activity, cytotoxic effect and the underlying mechanism of a novel chemically modified, non-carbonyl compound enriched Curcuma longa L. (C. longa) extract (CMCE). CMCE (1 or 10 μg/mL; 14 h) significantly decreased LPS (50-100 ng/mL) induced TNF-α and IL-1β production in THP-1 cells, human, and mouse whole blood as measured by ELISA. LPS-induced IRAK1, MAPK activation, TLR4 expression, TLR4-MyD88 interaction, and IκBα degradation were significantly reduced in CMCE pre-treated THP-1 cells as assessed by Western blotting. CMCE (30, 100, and 300 mg/kg; 10 days p.o.) pre-treated and LPS (10 mg/kg) challenged Swiss mice exhibited attenuated plasma TNF-α, IL-1β, nitrite, aortic iNOS expression, and vascular dysfunction. In a PI permeability assay, cell lines derived from acute myeloid leukemia were most sensitive to the cytotoxic effects of CMCE. Analysis of Sub-G1 phase, Annexin V-PI positivity, loss of mitochondrial membrane potential, increased caspase-3, and PARP-1 activation confirmed CMCE induced apoptosis in HL-60 cells. IRAK inhibition also sensitized HL-60 cells to CMCE induced cytotoxicity. The present study defines the mechanism underlying the action of CMCE and suggests a therapeutic potential for its use in sepsis and leukemia.

Apoptotic mechanisms of N1-acetylacetone, N4-4-methoxy-salicylidene-thiosemicarbazide chelating with Nickel(II) on HL60 leukemia cells.

Thiosemicarbozone complexes that have a broad spectrum of biological activity are formed as a result of condensation reaction between thiosemicarbazide [H2N(C=S)-NH-NH2] and carbonyl-containing compounds. A new Nickel(II) complexes with N1-acetylacetone, N4-4-methoxy-salicylidene-thiosemicarbazidato ligand was synthesized and characterized. We studied the antileukemic activity of the Ni(II) thiosemicarbazone compound and assessed their potential for drug development. Specifically, the effects of this Ni(II) thiosemicarbazone compound on intracellular signal nodes and apoptotic pathways were investigated. According to our results, the Ni(II) thiosemicarbazone compound has apoptotic activity against HL60 cells. Moreover, while Ni(II) thiosemicarbazone compound significantly increased levels of p53 and cleaved caspase-3 proteins, it decreased level of Phospho-Akt1 protein in HL60 cells. The Ni(II) thiosemicarbazone compound could induce HL60 cell apoptosis through inhibiting of PI3K/Akt pathway. These results showed that Ni(II) thiosemicarbozone compound might be an antileukemic agent.

Sonodynamic therapy induces apoptosis of human leukemia HL-60 cells in the presence of protoporphyrin IX.

Sonodynamic therapy (SDT) is expected to be a novel therapeutic strategy for tumor. The protoporphyrin IX disodium salt (PpIX), a photosensitizer, can be activated by ultrasound. The present study aims to investigate apoptosis of HL-60 cells induced by PpIX-mediated SDT. 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was adopted to examine cell toxicity. Apoptosis was detected using Annexin V-PE/7-amino-actinomycin D (7-AAD) double staining. Detection of apoptotic bodies was examined by Hoechst33342 (HO) staining. Western blotting was used to analyze the protein of caspase-3 and poly ADP-ribose polymerase (PARP). Intracellular reactive oxygen species (ROS) was detected by a flow cytometer after exposures. Compared with PpIX alone and ultrasound alone groups, the synergistic cytotoxicity of PpIX plus ultrasound were significantly boosted. In addition, as determined by Annexin V-PE/7-AAD staining, SDT significantly induced HL-60 cell apoptosis, the obvious nuclear condensation was also found with HO staining at 4 hours post-SDT treatment. Furthermore, Western blotting showed visible enhancement of caspase-3 and PARP cleavage in this process. Besides, intracellular ROS production was significantly enhanced after SDT. Our findings demonstrate that PpIX-mediated SDT could induce apoptosis on HL-60 cells, suggesting that apoptosis is an important mechanism of cell death induced by PpIX-mediated SDT.

15,16-Dihydrotanshinone I from the Functional Food Salvia miltiorrhiza Exhibits Anticancer Activity in Human HL-60 Leukemia Cells: in Vitro and in Vivo Studies.

15,16-Dihydrotanshinone I (DHTS) is extracted from Salvia miltiorrhiza Bunge which is a functional food in Asia. In this study, we investigated the apoptotic effect of DHTS on the human acute myeloid leukemia (AML) type III HL-60 cell line. We found that treatment with 1.5 μg/mL DHTS increased proapoptotic Bax and Bad protein expressions and activated caspases-3, -8, and -9, thus leading to poly ADP ribose polymerase (PARP) cleavage and resulting in cell apoptosis. DHTS induced sustained c-Jun N-terminal kinase (JNK) phosphorylation and Fas ligand (FasL) expression. The anti-Fas blocking antibody reversed the DHTS-induced cell death, and the JNK-specific inhibitor, SP600125, inhibited DHTS-induced caspase-3, -8, -9, and PARP cleavage. In a xenograft nude mice model, 25 mg/kg DHTS showed a great effect in attenuating HL-60 tumor growth. Taken together, these results suggest that DHTS can induce HL-60 cell apoptosis in vitro and inhibit HL-60 cell growth in vivo; the underlying mechanisms might be mediated through activation of the JNK and FasL signal pathways.

Effects of As2O3 on the Proliferation, Differentiation and Apoptosis of HL-60 Cells and Its Related Mechanisms

To investigate the effects of arsenic trioxide (As2O3) on the proliferation, differentiation and apoptosis of HL-60 cells in vitro and explore the underlying mechanisms. After HL-60 cells were treated with different concentration of As2O3, the cell proliferation was determined by MTS/PES method, the differentiation state was detected by the nitroblue tetrazolium (NBT) reduction test; flow cytometry was used to analyze the apoptosis and expression of CD11b. In addition, SYBR Green real-time RT-PCR was used to measure the mRNA levels of C-FES, BCL-2, BAX, survivin , P21 and P27. As2O3 could obviously inhibit the proliferation of HL-60 cells, and the effect was in dose- and time-dependent manners (r=-0.967; r=-0.954). Low concentration (0.1, 0.5 and 1.0 µmol/L) of As2O3 could significantly promote the differentiation of HL-60 cells, the cells exhibited a higher NBT-reducing ability and expressed far more CD11b antigens. High concentration (2.5 and 5.0 µmol/L) of As2O3 induced HL-60 cell apoptosis, but the ability of promoting differentiation decreased. The expression of C-FES mRNA significantly increased after being treated with As2O3 at the concentrations 1.0 and 5.0 µmol/L, and the former is more obvious, which confirmed that C-FES mRNA level paralleled the cell differentiation degree. Also, the expression of BCL-2 and survivin significantly decreased, while the expression of BAX, P21 and P27 was significantly upregulated in HL-60 cells after being treated with 5.0 µmol/L As2O3. As2O3 can significantly suppress cell proliferation, promote the differentiation and induce the apoptosis in HL-60 cells, and the mechanism of As2O3 anti-tumor activity may be involved in the regulation of C-FES, cell cycle and apoptosis-related genes.

The Effect of Decitabine Combined with Arsenic Trioxide on DAPK Gene and HL-60 Cell Proliferation and Apoptosis

Purpose: Our study was to detect the effect of Decitabine (DAC) combined with arsenic trioxide (AS2O3) on DAPK gene and HL-60 cell proliferation and apoptosis. Methods: DAC and AS2O3 monotherapy, combination treatment and DAC pretreatment were used in this study after incubating with HL-60 cell for 24 h, 48 h, 72 h. CCK8 was used to detect the cell proliferation of HL-60 cell. Flow cytometry was used to detect the cell apoptosis. Then, we used RT-PCR to obtain the gene expression level of DAPK. Results: HL-60 cells were treated with different concentrations of DAC (20 μmol/L, 40 μmol/L, 80 μmol/L), AS2O3 (1 μmol/L, 2.5 μmol/L, 5 μmol/L) monotherapy for 24 h, 48 h, 72 h; along with the extension of the drug concentration and time, proliferation inhibition rate had gradually increased. Monotherapy of DAC, AS2O3 could inhibit the proliferation and induce apoptosis of HL-60 cells, and was time- and dose-dependent. DAC (80 μmol/L) was firstly used for pretreatment, and then, different concentrations of AS2O3 (1 μmol/L, 2.5 μmol/L, 5 μmol/L) were used for 24 h, 48 h, 72 h. It was found that cell proliferation inhibition rate and apoptosis rate had increased significantly. When the two drugs were used together, the increasing proliferation inhibition rate, apoptosis rate and DAPK had become more obvious. Conclusion: DAC and AS2O3 had a synergetic effect for the HL-60 cell proliferation inhibition, apoptosis and expression of DAPK.

Glabridin mediate caspases activation and induces apoptosis through JNK1/2 and p38 MAPK pathway in human promyelocytic leukemia cells.

BackgroundGlabridin, a prenylated isoflavonoid of G. glabra L. roots, has been associated with a wide range of biological properties such as regulation of energy metabolism, estrogenic, neuroprotective, anti-osteoporotic, and skin-whitening in previous studies. However, the effect of glabridin on tumor cells metastasis has not been clearly clarified. Here, the molecular mechanism by which glabridin anticancer effects in human promyelocytic leukemia cells was investigated.Methodology and Principal FindingsThe results showed that glabridin significantly inhibited cell proliferation of four AML cell lines (HL-60, MV4-11, U937, and THP-1). Furthermore, glabridin induced apoptosis of HL-60 cells through caspases-3, -8, and -9 activations and PARP cleavage in dose- and time-dependent manner. Moreover, western blot analysis also showed that glabridin increase phosphorylation of ERK1/2, p38 MAPK and JNK1/2 in dose- and time-dependent manner. Inhibition of p38 MAPK and JNK1/2 by specific inhibitors significantly abolished the glabridin-induced activation of the caspase-3, -8 and -9.ConclusionTaken together, our results suggest that glabridin induced HL-60 cell apoptosis through p38 MAPK and JNK1/2 pathways and could serve as a potential additional chemotherapeutic agent for treating AML.

Study on human promyelocytic leukemia HL-60 cells apoptosis induced by fucosterol

In this study, we investigated the effect of fucosterol on HL-60 and the molecular mechanism. HL-60 Cells were treated with fucosterol, and 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) method was used to study fucosterol anti-tumor activity. Morphology of HL-60 cells was observed. Flow cytometry (FCM) was employed to detect the cell cycle. Laser scanning confocal microscope (LSCM) was used to analyze mitochondrial membrane potential (MMP) and the expressions of Fas, FasL, Fadd and Caspase-8. Western blot was performed to analyze the expressions of Cyt-C, Pro-Caspase-9 and Pro-Caspase-3. Caspase activity kits were used to determine the activity of Caspase-9, Caspase-8 and Caspase-3. The results showed fucosterol could inhibit the growth of HL-60 cells, and the cell cycle was arrested at G2/M phase. HL-60 cells showed obvious apoptosis morphology. After being treated with fucosterol for 24 h, HL-60 cells decreased MMP, induced Cyt-C release and Caspase-9, Caspase-3 activation. Fucosterol also increased the protein expression of Fas, FasL, Fadd and Caspase-8. Moreover, the activity of Caspase-9, Caspase-8 and Caspase-3 was increased significantly. In conclusion, Fucosterol can induce HL-60 cells apoptosis, suggesting that it may be a potent agent for cancer prevention and treatment.

Study on Apoptosis of Human Promyelocytic Leukemia HL-60 Cells Induced by Fucosterol via Mitochondrial Pathway

The purpose of this study is to investigate the effect of fucosterol on the induction of apoptosis and the molecular mechanism involved in Human promyelocytic leukemia HL-60 Cells. HL-60 Cells were treated with different concentrations of fucosterol at different time. MTT method was used to study fucosterol anti-tumor activity. Morphology observation was performed to determine the effects of fucosterol on apoptosis of HL-60 cells. Flow cytometry (FCM) was used to detect the cell cycle. Laser scanning confocal microscope (LSCM) was used to analyze mitochondrial membrane potential (MMP). Western blot was performed to analyze the expressions of Cyt-C, Caspase-9 and Caspase-3. The results showed fucosterol could inhibit the growth of HL-60 cells, and the apoptosis morphology for 48 h treatment was obvious, which showed cell protuberance, cytoplasm concentrated and apoptotic body. Fucosterol treatment for 24 h decreased MMP in dose-dependent manners. It also induced the release of Cyt-C and the activation of Caspase-9 and-3. In conclusion, Fucosterol could induce HL-60 cells apoptosis through a mitochondrial pathway.

Study on Apoptosis of Human Promyelocytic Leukemia HL-60 Cells Induced by Fucosterol via Death Receptor Pathway

The purpose of this study is to investigate the effect of fucosterol on the induction of apoptosis and the molecular mechanism involved in Human promyelocytic leukemia HL-60 Cells. HL-60 Cells were treated with different concentrations of fucosterol at different time. MTT method was used to study fucosterol anti-tumor activity. Morphology observation was performed to determine the effects of fucosterol on apoptosis of HL-60 cells. Flow cytometry (FCM) was used to detect the cell cycle. Laser scanning confocal microscope (LSCM) was used to analyze the expressions of Fas, FasL, Fadd and Caspase-8. Caspase activity kits were used to determine the activity of Caspase-8 and Caspase-3. The results showed fucosterol could inhibit the growth of HL-60 cells, and the apoptosis morphology for 48 h treatment was obvious, which showed cell protuberance, cytoplasm concentrated and apoptotic body. Fucosterol treatment for 24 h increased the protein expression of Fas, FasL, Fadd and Caspase-8. It also showed that the activity of Caspase-3 and Caspase-8 has increased significantly. In conclusion, Fucosterol could induce HL-60 cells apoptosis via death receptor pathway.

Mechanism of HL-60 cells apoptosis induced by proteasome inhibitor MG132

The purpose of this study was to elucidate the apoptosis, apoptotic pathway of HL-60 cells induced by proteasome inhibitor MG132 and its effect on allogeneic mixed lymphocyte reaction. Apoptosis of HL-60 cells was detected by flow cytometry, the expression of P21, P27 and P53 proteins in HL-60 cells treated with MG132 was assayed by Western blot. The HL-60 cells were treated with 1 µmol/L MG132 for 48 h, and irradiated by 75 Gy of (60)Co γ-ray, but their antigenicity was preserved. The effect of irradiated HL-60 cells treated with MG132 on proliferation of peripheral blood mononuclear cells (PBMNC) was measured by CCK-8 method. The results showed that the apoptotic rate of MG132-treated HL-60 cells increased in dose-and time-dependent manner. No significant changes in MG132-induced apoptosis were observed after inhibiting caspase-8 and caspase-9 pathway. The expression of P21 and P27 protein increased after treatment of HL-60 cells with MG132. CCK-8 test showed that HL-60 cells induced with low-dose of MG132 displayed the enhancing effect on proliferation of PBMNC. It is concluded that high dose of MG132 can induce the apoptosis of HL-60 cells, and has direct killing effect on HL-60 cells, but this inducing apoptotic effect on HL-60 cells can not be realized through caspase-8 and caspase-9 pathway. The P21 and P27 protein may be involved in MG132 induced HL-60 cell apoptosis. Low dose of MG132 promotes the proliferation of PBMNC in healthy individuals and enhance the immunity of organism.

Induction of apoptosis in human acute leukemia HL-60 cells by oligochitosan through extrinsic and intrinsic pathway

The underlying cellular and molecular mechanism about oligochitosan induced HL-60 cell apoptosis remained unknown. In the present study, we found oligochitosan treated HL-60 cells showed enhanced cleavage of poly (ADP-Ribose) polymerase PARP and p21 expression, accompanied with G0/G1cell cycle arrest. After treatment with oligochitosan, the pro-apoptotic molecules Fas, FADD and Bax were up-regulated whereas anti-apoptotic Bcl-2 expression in HL-60 cells was significantly decreased. Furthermore, galectin-9 mRNA expression was increased in the presence of oligochitosan. We thus over-expressed galectin-9S or galectin-9L and found galectin-9 could significantly increase the oligochitosan induced apoptotic rate of HL-60 cells. Collectively, our data demonstrated that oligochitosan might regulate cell cycle progression and induce HL-60 cell apoptosis through both extrinsic and intrinsic pathways.

Alkaloids from a deep ocean sediment-derived fungus Penicillium sp. and their antitumor activities

Four new alkaloids, including two new meleagrin analogs, meleagrin D (1) and E (2), and two new diketopiperazines, roquefortine H (3) and I (4), were isolated from a deep ocean sediment-derived fungus Penicillium sp. Meleagrin D (1) and E (2) possess unprecedented acetate-mevalonate-derived side chains on the imidazole moiety. These new meleagrins showed weak cytotoxicity against the A-549 cell line, whereas meleagrin B (5) and meleagrin (6), which were isolated previously from the same strain, induced HL-60 cell apoptosis or arrested the cell cycle through G(2)/M phase, respectively. The results indicate that the distinct substitutions on the imidazole ring significantly influence the cytotoxicity of the meleagrin alkaloids.

Changes and function of Bax and Fas in HL-60 cell apoptosis induced by two fungus polysaccharides

Objective To detect the proliferation inhibition and apoptosis of HL-60 cell induced by APS-1 and APS-2 isolated from Polyporus sp. M05 and to investigate its mechanism. Methods The proliferation inhibition was detected by living cells count method,and chosed proper concentration.Flow cytometry with propidium iodide staining was used to detect cell apoptosis. Semi-quantitative RT-PCR was used to detect the expression of apoptosis related gene. Results APS-1 and APS-2 could significantly inhibit the proliferation of HL-60 cells on a time and dose dependent manner. Apoptosis ratio increased to 47. 9% and 26. 8% after HL-60 cells were exposed to APS-1 and APS-2 respectively for 48 h,and the differences had statistical significance (P <0.01). After being induced by APS-1,mRNA of Bax,Fas,Caspase-3 was upregulated. And after being induced by APS-2,mRNA of Bax,Caspase-3 was upregulated,while Fas mRNA did not change. Conclusion APS-1 and APS-2 can inhibit the proliferation and induce apoptosis of HL-60 cells. Mechanism of HL-60 cell apoptosis induced by APS-1 is related to both mitochondrial pathway and Fas signaling pathway,while apoptosis induced by APS-2 is only related to mitochondrial pathway. Key words: Fungi; Polysaccharides; HL-60 cells; Apoptosis

HL-60 Cell Death Induced by Lycorine Is Due to p21-Mediated Cell Cycle Arrest and TNF-α Signaling Stimulation.

Abstract 4158Lycorine displays various biological functions including remarkable anti-tumor effect. We previously reported that lycorine induced anti-leukemia effect via arresting cell cycle and inducing apoptosis on human acute promyelocytic leukemia (APL) cell line HL-60. To explore the molecular mechanism how lycorine induced HL-60 cell apoptosis, cDNA microarray was used to investigate the expression profile of 494 apoptosis-associated genes. Real-time RT-PCR, Western blotting and immunocytochemistry were used to analyze the expression of related genes, as well as the modification and distribution of related proteins in the presence of lycorine. The results showed that 89 differential genes were expressed significantly (Cy3:Cy5 > 2 or < 0.5) among all the 494 apoptosis-related genes. 78 genes were up-regulated and 11 genes were down-regulated. We are particularly interested in the expression increase of p21 (9.271 folds) and TNF-α (8.242 folds). Furthermore, we found that lycorine could down-regulate p21-related gene expression including Cdc2, Cyclin B, Cdk2 and Cyclin E, promote the truncation of Bid protein and the release of cytochrome c from mitochondria, decrease the phosphorylation of IκB, block the nuclear import of NF-κB and down-regulate expression of survivin. This study revealed that lycorine decreased HL-60 cells survival through p21-mediated cell cycle arrest and stimulation of TNF-α signaling pathway which induced apoptosis. Disclosures:No relevant conflicts of interest to declare.