OBJECTIVE: To observe whether HSP70 could protect against H2O2-induced apoptosis in C2C12 myogenic cells by inhibiting Smac release from the mitochondria. METHODS: HSP70 gene and full length Smac gene was transiently transfected in C2C12 myogenic cells by lipofectamine and the protein levels of HSP70 and Smac were analysed by Western blotting. Hoechst 33 258 staining was used to examine cell morphological changes and to calculate percentage of apoptotic nuclei. DNA ladder pattern on agarose gel electrophoresis was used to observe the DNA fragmentation. Activities of caspase-3 and caspase-9 were assayed with Western blotting. The release of Smac from the mitochondria to the cytoplasm was observed by immunofluorescence. RESULTS: H2O2 ( 0.5 mmol/L ) activated caspase-3, caspase-9 8 h after the treatment and specific morphological changes of apoptosis 12 h after the treatment, and overexpression of Smac significantly promoted H2O2-induced activation of caspase-3, caspase-9 and apoptosis in C2C12 myogenic cells. HSP70 overexpression significantly inhibited H2O2-induced and Smac-promoted apoptosis, as shown by no specific DNA ladder pattern in agarose gel electrophoresis, decrease of percentage of apoptotic nuclei, and marked inactivation of caspase-3 and caspase-9. HSP70 could inhibit the release of Smac from the mitochondria to the cytoplasm 2 h after the treatment by H2O2. CONCLUSION HSP70 inhibits Smac release from the mitochondria and protects against H2O2-induced apoptosis in C2C12 myogenic cells.
Apoptosis ; drug effects ; Apoptosis Regulatory Proteins ; Cells, Cultured ; HSP70 Heat-Shock Proteins ; pharmacology ; Humans ; Hydrogen Peroxide ; Intracellular Signaling Peptides and Proteins ; metabolism ; Mitochondria, Heart ; drug effects ; metabolism ; Mitochondrial Proteins ; antagonists & inhibitors ; metabolism ; Myoblasts ; metabolism ; Myocytes, Cardiac ; drug effects ; metabolism

Cell Proliferation ; drug effects ; DNA Methylation ; drug effects ; Humans ; K562 Cells ; Stilbenes ; pharmacology ; WT1 Proteins ; metabolism

Drug resistance and relapse are the major challenge for current treatment of acute leukemia. It is critical for ultimately curing leukemia to overcome chemoresistance of leukemic stem cells (LSC) and to eradicate LSC. Recent studies have found that abnormal activated Hedgehog (HH) signaling pathway plays an important role in a wide variety of tumors and regulates multi-drug resistance of LSC. This review briefly summarizes the molecular mechanism of HH signal pathway inducing drug resistance of LSC and leading to novel strategies for eradicating LSC.
Drug Resistance, Neoplasm ; Hedgehog Proteins ; metabolism ; Humans ; Leukemia ; metabolism ; Neoplastic Stem Cells ; drug effects ; Signal Transduction

Oxidized low density lipoprotein (oxLDL) can trigger intracellular production of reactive oxygen species and lipid peroxidation (LPO), and is thought to contribute to initiation and progression of atherosclerosis. In order to understand the correlation between oxLDL and macromolecular damage, we measured levels of LPO-derived miscoding etheno-DNA adducts and LPO-modified proteins in cultured human vascular endothelial and smooth muscle cells after incubation with oxLDL for up to 48 h. A semi-quantative analysis method for 1, N6-ethenodeoxyadenosine (ɛdA) by immunohistochemistry was applied. After oxLDL stimulation, ɛdA-stained nuclei were significantly increased in both endothelial and smooth muscle cells. Similarly, 4-hydroxy-2-nonenal (4-HNE)-modified proteins, as analyzed by immunohistochemistry and Western blotting, were also 3-5 fold increased. It was concluded LPO-derived etheno-DNA adducts and LPO-modified proteins are strongly induced by oxLDL in human vascular endothelial and smooth muscle cells. This macromolecular damage may contribute to the dysfunction of arterial endothelium and the onset of atherosclerosis.
DNA ; metabolism ; Endothelium, Vascular ; cytology ; drug effects ; metabolism ; Humans ; Lipid Peroxidation ; drug effects ; Lipoproteins, LDL ; pharmacology ; Muscle, Smooth ; cytology ; drug effects ; metabolism ; Proteins ; metabolism

To explore the mechanism of autophagic death of acute myelocytic leukemia cell U937 induced by clofarabine, the MTT bioassay was used to analyze the growth inhibitory effect and half inhibition concentration on U937 incubated in vitro with different concentrations of clofarabine for 24 and 48 hours, and the flow cytometry was used to detect the autophagy rate of U937. The expression of Beclin 1 in U937 treated by clofarabine for 48h was measured by Western blot. The results indicated that when U937 cells were treated with 0.01 µmol/L and 0.15 µmol/L clofarabine for 48 hours, the proliferation inhibition rate was 46.92% ± 4.24% and 86.10% ± 1.16%, and the half inhibition concentration of clofarabine was 0.022 µmol/L. With 0.01 µmol/L and 0.1 µmol/L clofarabine on U937 for 48 hours, the autophagy rate was 11.0033% ± 1.4387% and 59.4133% ± 3.5409%, and increased in dose-dependent manner (r = 0.99). Meanwhile the Beclin 1 was upregulated along with increase of clofarabine concentration, as compared with control group, the difference was statistically significant (P < 0.05). It is concluded that the different concentrations of clofarabine can significantly inhibit the proliferation of U937 in dose-dependent manner, and the mechanism of autophagic cell death in U937 may be associated with the upregulation of Beclin 1 expression.
Adenine Nucleotides ; pharmacology ; Apoptosis ; drug effects ; Apoptosis Regulatory Proteins ; metabolism ; Arabinonucleosides ; pharmacology ; Autophagy ; drug effects ; Beclin-1 ; Cell Proliferation ; drug effects ; Humans ; Membrane Proteins ; metabolism ; U937 Cells

Caenorhabditis elegans hid-1 gene was first identified in a screen for mutants with a high-temperature-induced dauer formation (Hid) phenotype. Despite the fact that the hid-1 gene encodes a novel protein (HID-1) which is highly conserved from Caenorhabditis elegans to mammals, the domain structure, subcellular localization, and exact function of HID-1 remain unknown. Previous studies and various bioinformatic softwares predicted that HID-1 contained many transmembrane domains but no known functional domain. In this study, we revealed that mammalian HID-1 localized to the medial- and trans- Golgi apparatus as well as the cytosol, and the localization was sensitive to brefeldin A treatment. Next, we demonstrated that HID-1 was a peripheral membrane protein and dynamically shuttled between the Golgi apparatus and the cytosol. Finally, we verified that a conserved N-terminal myristoylation site was required for HID-1 binding to the Golgi apparatus. We propose that HID-1 is probably involved in the intracellular trafficking within the Golgi region.
Animals ; Brefeldin A ; pharmacology ; Cell Line, Tumor ; Cytosol ; drug effects ; metabolism ; Humans ; Intracellular Space ; drug effects ; metabolism ; Membrane Proteins ; metabolism ; Protein Transport ; drug effects ; Rats ; Vesicular Transport Proteins ; metabolism ; trans-Golgi Network ; drug effects ; metabolism

OBJECTIVETo investigate the expression of mitochondria-mediated apoptosis pathway related genes bcl-2, Bax, survivin and Smac/DIABLO in bufalin induced HL-60 cell apoptosis.

METHODSCell viability was determined by trypan blue exclusion, apoptosis by morphology and flow cytometry, expressions of Bcl-2, Bax, Survivin, Smac/DIABLO and caspase-3 protein by Western blot, and expression of survivin mRNA by RT-PCR.

RESULTSProliferation of HL-60 cells was inhibited by bufalin and the IC(50) at 24, 48 and 72 h were 25.8, 8.0 and 2.1 nmol/L, respectively. Apoptosis was induced when the cells were treated with bufalin at concentrations of 50.0 nmol/L and higher. Compared with the control, HL-60 cells treated with bufalin at 50.0 nmol/L for 6, 12, 24 and 48 h showed decrease of Bcl-2 protein expression to 88.6%, 53.3%, 19.2% and 9.5%, Bcl-2/Bax ratio (control 2.0) to 1.7, 1.1, 0.4 and 0.2, Survivin protein expression to 75.2%, 54.8%, 37.5% and 20.3%, and survivin mRNA to 85.7%, 39.4%, 12.5%and 0%, respectively. The expression of Smac/DIABLO protein was downregulated to 77.5% (12 h), 21.2% (24 h) and 15.3% (48 h) in mitochondrial fraction and upregulated to 1.4-(12h), 2.0-(24 h) and 3.5- folds (48 h) in cytosolic fraction, respectively. The active subunits of caspase-3 were displayed after treatment for 8 h till 48 h.

CONCLUSIONApoptosis induced by bufalin is related to downregulation of expressions of bcl-2 and survivin, decrease of Bcl-2/Bax ratio, mitochondrial release of Smac/DIABLO, and activation of caspase-3. The mitochondria-mediated apoptotic pathway may be involved in the apoptosis induced by bufalin in HL-60 cells.

Apoptosis ; drug effects ; Bufanolides ; pharmacology ; Caspase 3 ; metabolism ; Down-Regulation ; drug effects ; HL-60 Cells ; Humans ; Inhibitor of Apoptosis Proteins ; Intracellular Signaling Peptides and Proteins ; metabolism ; Microtubule-Associated Proteins ; metabolism ; Mitochondrial Proteins ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism

The peptide angiotensin IV (Ang IV) is a derivative of angiotensin II. While insulin regulated amino peptidase (IRAP) has been proposed as a potential receptor for Ang IV, the signalling pathways of Ang IV through IRAP remain elusive. We applied high-resolution mass spectrometry to perform a systemic quantitative phosphoproteome of Neura-2A (N2A) cells treated with and without Ang IV using sta ble-isotope labeling by amino acids in cell culture (SILAC), and identified a reduction in the phosphorylation of a major Ser/Thr protein phosphorylase 1 (PP1) upon Ang IV treatment. In addition, spinophilin (spn), a PP1 regulatory protein that plays important functions in the neural system, was expressed at higher levels. Immunoblotting revealed decreased phosphorylation of p70S6 kinase (p70(S6K)) and the major cell cycle modulator retinoblastoma protein (pRB). These changes are consistent with an observed decrease in cell proliferation. Taken together, our study suggests that Ang IV functions via regulating the activity of PP1.
Angiotensin II ; analogs & derivatives ; pharmacology ; Animals ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Membrane ; drug effects ; metabolism ; Cell Nucleus ; drug effects ; metabolism ; Cell Proliferation ; drug effects ; Humans ; Mice ; Microfilament Proteins ; metabolism ; Nerve Tissue Proteins ; metabolism ; Neurons ; cytology ; Phosphorylation ; drug effects ; Protein Phosphatase 1 ; chemistry ; metabolism ; Protein Transport ; drug effects ; Proteome ; metabolism ; Rats ; Threonine ; metabolism ; Up-Regulation ; drug effects

Small, cysteine-rich, highly stable antifungal proteins secreted by filamentous Ascomycetes have great potential for the development of novel antifungal strategies. However, their practical application is still limited due to their not fully clarified mode of action. The aim of this work was to provide a deep insight into the antifungal mechanism of Neosartorya fischeri antifungal protein (NFAP), a novel representative of this protein group. Within a short exposure time to NFAP, reduced cellular metabolism, apoptosis induction, changes in the actin distribution and chitin deposition at the hyphal tip were observed in NFAP-sensitive Aspergillus nidulans. NFAP did show neither a direct membrane disrupting-effect nor uptake by endocytosis. Investigation of A. nidulans signalling mutants revealed that NFAP activates the cAMP/protein kinase A pathway via G-protein signalling which leads to apoptosis and inhibition of polar growth. In contrast, NFAP does not have any influence on the cell wall integrity pathway, but an unknown cell wall integrity pathway-independent mitogen activated protein kinase A-activated target is assumed to be involved in the cell death induction. Taken together, it was concluded that NFAP shows similarities, but also differences in its mode of antifungal action compared to two most investigated NFAP-related proteins from Aspergillus giganteus and Penicillium chrysogenum.
Actins ; metabolism ; Antifungal Agents ; pharmacology ; Apoptosis ; drug effects ; Aspergillus nidulans ; cytology ; drug effects ; growth & development ; Cell Membrane ; drug effects ; metabolism ; Cell Wall ; drug effects ; metabolism ; Chitin ; metabolism ; Endocytosis ; drug effects ; Fungal Proteins ; pharmacology ; GTP-Binding Proteins ; metabolism ; Hyphae ; cytology ; drug effects ; Microbial Viability ; drug effects ; Neosartorya ; chemistry ; Signal Transduction ; drug effects

OBJECTIVETo investigate the effect of 2,5-hexanedione (HD) on degradation of low-molecular-weight neurofilaments (NF-L) in nervous tissue of rats, and to explore the molecular mechanism of n-hexane neuropathy.

METHODSFifty male Wistar rats were randomly divided into one-week poisoning group (n = 10), two-week poisoning group (n = 10), three-week poisoning group (n = 10), four-week poisoning group (n = 10), and control group (n = 10). In the four poisoning groups, a rat model of n-hexane neuropathy was established by intraperitoneal injection of HD (400 mg/kg/d). The change in the sciatic nerve ultrastructure of each rat was observed under an electron microscope. The progression of HD-induced peripheral neuropathy was evaluated using a gait scoring system. The degradation rates of NF-L in the sciatic nerve and spinal cord of each rat were measured by Western Blotting.

RESULTSThe rats showed decrease in muscle strength and abnormal gait after two weeks of HD poisoning and mild or moderate paralysis after four weeks of HD poisoning. The sciatic nerve showed degenerative change, according to electron microscope observation. Compared with the control group, the two-week poisoning group, three-week poisoning group, and four-week poisoning group had the NF-L degradation rates decreased by 25.8%, 70.4%, and 69.7%, respectively, in the supernatant fraction of sciatic nerve, and by 14.7%, 64.6%, and 67.3%, respectively, in the sediment fraction of sciatic nerve, all showing a significant difference (P < 0.01). Compared with the control group, the one-week poisoning group had the NF-L degradation rate decreased by 33.87% in the supernatant fraction of spinal cord, the four-week poisoning group had the NF-L degradation rate increased by 16.2% in the supernatant fraction of spinal cord, and the one-week poisoning group and two-week poisoning group had the NF-L degradation rates decreased by 46.3% and 13.0% in the sediment fraction of spinal cord, all showing a significant difference (P < 0.01).

CONCLUSIONHD poisoning significantly inhibits NF-L degradation in the sciatic nerve, which may be associated with NF degeneration and accumulation in the axons of patients with n-hexane neuropathy.

Animals ; Hexanes ; poisoning ; Hexanones ; pharmacology ; Male ; Nerve Tissue ; drug effects ; metabolism ; physiopathology ; Neurofilament Proteins ; drug effects ; metabolism ; Rats ; Rats, Wistar ; Sciatic Nerve ; drug effects ; metabolism ; physiopathology