OBJECTIVETo investigate the role of autophagy in MnCl2-induced apoptosis in human bronchial epithelial 16HBE cells.

METHODSCell proliferation was measured by MTT assay. Mitochondrial membrane potential (MMP) and apoptosis were measured by flow cytometry. Autophagic vacuoles were detected by fluorescence microscopy. Cellular levels of apoptosis and autophagy-related proteins were measured by western blotting.

RESULTS16HBE cell proliferation was inhibited by MnCl2 in a dose- and time-dependent manner. MnCl2-induced 16HBE cell growth inhibition was related to MMP depolarization prior to the induction of apoptosis. Our data revealed that MnCl2-induced apoptosis in 16HBE cells was mediated by decreased expression of Bcl-2 and increased levels of cleaved caspase-3. It was observed that when we exposed 16HBE cells to MnCl2 in a dose-dependent manner, the formation of autophagic vacuoles and the levels of LC-3B-II were elevated. RNA interference of LC3B in these MnCl2-exposed cells demonstrated that MMP loss and apoptosis were enhanced. Additionally, the pan-caspase inhibitor Z-VAD-FMK increased the cellular levels of Bcl-2 and decreased apoptosis, but did not affect the cellular levels of LC3B in MnCl2-treated 16HBE cells.

CONCLUSIONMnCl2 dose- and time-dependently inhibits 16HBE cell proliferation and induces MMP loss and apoptosis. Autophagy acts in a protective role against MnCl2-induced apoptosis in 16HBE cells.

Amino Acid Chloromethyl Ketones ; pharmacology ; Apoptosis ; drug effects ; Autophagy ; drug effects ; physiology ; Bronchi ; Cell Line ; Chlorides ; pharmacology ; Down-Regulation ; Epithelial Cells ; drug effects ; Gene Expression Regulation ; drug effects ; Humans ; Manganese Compounds ; pharmacology

BACKGROUNDPyroptosis is the term for caspase-1-dependent cell death associated with pro-inflammatory cytokines. The role of alveolar macrophage (AM) pyroptosis in the pathogenesis of the acute lung injury and acute respiratory distress syndrome (ALI/ARDS) remains unclear.

METHODSC57BL/6 wild-type mice were assigned to sham, lipopolysaccharide (LPS) + vehicle, LPS + acetyl-tyrosyl-valyl- alanyl-aspartyl-chloromethylketone (Ac-YVAD-CMK) and LPS + Z-Asp-Glu-Val-Asp-fluoromethylketone groups. Mice were given intraperitoneal (IP) injections of LPS. Drugs were IP injected 1 h before LPS administration. Mice were sacrificed 16 h after LPS administration, and AMs were isolated. Western blot analysis for active caspase-1 and cleaved caspase-3, evaluation of lung injury and a cytokine release analysis were performed. AMs were treated with LPS and adenosine triphosphate (ATP); caspase-1-dependent cell death was evaluated using flow cytometry; the apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) pyroptosomes were examined by immunofluorescence.

RESULTSThe expression of activated caspase-1 in AMs was enhanced following LPS challenge compared with the sham group. In the ex vivo study, the caspase-1/propidium iodide-positive cells, caspase-1 specks and ASC pyroptosomes were up-regulated in AMs following LPS/ATP stimulation. The specific caspase-1 inhibitor Ac-YVAD-CMK inhibited the activation of caspase-1 and pyroptotic cell death. Ac-YVAD-CMK also reduced the lung injury, pulmonary edema and total protein in bronchoalveolar lavage fluid (BALF). In addition, Ac-YVAD-CMK significantly inhibited interleukin-α2 (IL-1α2) release both in serum and BALF and reduced the levels of IL-18, tumor necrosis factor-α± (TNF-α±), High Mobility Group Box 1 (HMGB1) in BALF during LPS-induced ALI/ARDS.

CONCLUSIONSThis study reported AM pyroptosis during LPS-induced ALI/ARDS in mice and has demonstrated that Ac-YVAD-CMK can prevent AM-induced pyroptosis and lung injury. These preliminary findings may form the basis for further studies to evaluate this pathway as a target for prevention or reduction of ALI/ARDS.

Acute Lung Injury ; chemically induced ; prevention & control ; Amino Acid Chloromethyl Ketones ; pharmacology ; Animals ; Lipopolysaccharides ; toxicity ; Macrophages, Alveolar ; drug effects ; Male ; Mice ; Mice, Inbred C57BL ; Oligopeptides ; pharmacology ; Pyroptosis ; drug effects

OBJECTIVE: To explore the exact mechanisms of programmed cell death (PCD) induced by Type II anti-CD20 mAb in CD20+ non-Hodgkin lymphoma (NHL) cells, and to provide theoretical basis for anti-tumor ability of new CD20 mAb.
 METHODS: After incubation with Rituximab (a Type I anti-CD20 mAb) and Tositumomab (a Type II anti-CD20 mAb), Raji cells were stained by annexin V & propidium iodide (PI). The ratio of programmed death cells were measured by two channel flow cytometry (FCM). Before the treatment of anti-CD20 mAbs, Raji cells was incubated with a caspase inhibitor carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]- fluoromethylketone (Z-VAD-FMK) and a dihydroceramide synthase inhibitor fumonisin B1 (FB1) for 30 minutes to assess their inhibitory effect on PCD. High performance liquid chromatography (HPLC) was utilized to compare the ratio of programmed death cells between the pretreatment group (treated by Rituximab and Tositumomab) and the non-pretreatment group. The anti-CD20 mAbs-treated Raji cells were collected, and the ceramide levels in the Raji cells in the different pretreatment groups were also examined by HPLC, and the inhibitory effect of FB1 on the changes of ceramide levels in the Raji cells was measured. The Raji cells were incubated with different concentration C2-ceramide, C2-Ceramide-induced PCD was also evaluated by annexin V & PI staining after 16 hours. 
 RESULTS: Tositumomab (10 µg/mL) but not Rituximab (10 µg/mL) can induce significant PCD (28.6±4.2)% in Raji cells, with significant difference (t=26.48, P<0.01), which cannot be blocked by Z-VAD-FMK with a concentration range from 10 to 30 µmol/L (F=3.01, P>0.05). The cellular ceramide levels in Raji cells were significantly elevated after the treatment of Tositumomab (t=28.48, P<0.01). C2-ceramide can significantly induce PCD in Raji cells in a dose-dependent manner with a concentration range from 5 to 40 µmol/L (F=2.71, P>0.05). The dihydroceramide synthase inhibitor FB1 can significantly inhibit the elevated cellular ceramide levels (F=20.18, P<0.01) and cell programmed death induced by Tositumomab (F=17.02, P<0.01).
 CONCLUSION Type II but not Type I anti-CD20 mAbs can induce caspase independent PCD in CD20+ NHL cells through the elevation of cellular ceramide levels. The PCD is not associated with classic caspase pathway.
Amino Acid Chloromethyl Ketones ; Apoptosis ; drug effects ; Cell Line, Tumor ; drug effects ; Humans ; Lymphoma, Non-Hodgkin ; Rituximab ; pharmacology ; Sphingosine ; analogs & derivatives ; pharmacology

The present study is to elucidate the mechanisms underlying Gleevec-induced apoptosis of chronic myeloid leukemia (CML) K562 cells in vitro. The apoptotic cell death and cell cycle distribution after Gleevec treatment and the effect of PDCD4 siRNA on Gleevec-induced apoptosis of K562 cells were analyzed by flow cytometry. The effect of Gleevec on p-Crkl, caspase-3, PARP and PDCD4 protein levels, and the knockdown efficacy of PDCD4 siRNA were detected by Western blotting. The results showed that Gleevec dramatically suppressed the phosphorylation level of Crkl in a dose-dependent manner and induced significant apoptosis and G0/G1 cell cycle arrest of K562 cells in time- and dose-dependent manners. In addition, Gleevec activated caspase-3 and its downstream substrates PARP, and the caspase pan inhibitor Z-VAD-FMK (50 micromol x L(-1)) markedly reduced Gleevec-induced apoptosis from 47.97% +/- 10.56% to 31.05% +/- 9.206% (P < 0.05). Moreover, Gleevec significantly increased the protein expression of programmed cell death 4 (PDCD4). PDCD4 knockdown by siRNA reduced Gleevec-induced apoptosis from 46.97% +/- 14.32% to 42.8% +/- 11.43%. In summary, Gleevec induced apoptosis in K562 cells via caspase-3 activation.
Amino Acid Chloromethyl Ketones ; Apoptosis ; drug effects ; Benzamides ; pharmacology ; Caspase 3 ; metabolism ; Cell Cycle ; drug effects ; Humans ; Imatinib Mesylate ; K562 Cells ; Phosphorylation ; Piperazines ; pharmacology ; Pyrimidines ; pharmacology

OBJECTIVETo investigate the involvement of apoptosis inducing factor (AIF) in caspase-independent pathway mediating apoptosis of cultured renal tubular epithelial cells induced by cisplatin (CP).

METHODSWestern Blot analysis and real-time PCR were performed to detect cytosol AIF (cAIF), nuclear AIF (nAIF) and AIF mRNA expression in cultured renal epithelial cells (HK-2) treated with cisplatin (CP) at various concentrations (0 - 200 micromol/L) and time courses (0 - 12 h). Immunofluorescence analysis was used to detect the AIF protein distribution in HK-2 cells. Pan-caspase inhibitor (Z-VAD-FMK) and AIF-siRNA treatment, TUNEL and flow cytometer were used to measure the suppression of apoptosis induced by CP in HK-2 cells.

RESULTSThe expressions of cAIF, nAIF protein and AIF mRNA were all increased to some extent in HK-2 cells treated with CP at various concentrations and time points. cAIF expression was 2.3-fold (P < 0.05) increased after 25 micromol/L CP treatment for 12 h and 1.7-fold (P < 0.01) increased after 50 micromol/L CP treatment for 3 h, compared with that of control groups, and showed a concentration- and time-dependent increment. The nAIF expression reached a peak (4.3-fold increase) (P < 0.005) after 150 micromol/L CP treatment for 12 h and 3.7-fold incease (P < 0.05) after 50 micromol/L CP treatment for 9 h, compared with that of the 25 micromol/L group and 3 h group, respectively. The expression of nAIF was approximately consistent with cleaved-PARP expressive pattern. Real-time PCR showed that AIF mRNA increased gradually with prolonged treatment with 50 micromol/L CP and reached a peak at 9 h. Immunofluorescence assay showed AIF translocation from cytosol to nuclei in some cultured HK-2 cells treated with CP. Applying pan-caspase inhibitor (Z-VAD-FMK) and AIF-siRNA to CP-treated HK-2 cells, the apoptotic rates were decreased by 60.1% and 39.2%, respectively. The inhibitory effect on HK-2 cell apoptosis was even more significant with combination of both Z-VAD-FMK and AIF-siRNA.

CONCLUSIONThe AIF activation and translocation to nuclei with the increment of its mRNA expression mediates CP-induced apoptosis of renal tubular epithelial cells in vitro. It may provide a new therapeutic target for protecting from nephrotoxciity of cisplatin.

Amino Acid Chloromethyl Ketones ; pharmacology ; Antineoplastic Agents ; administration & dosage ; pharmacology ; Apoptosis ; drug effects ; Apoptosis Inducing Factor ; genetics ; metabolism ; Caspase Inhibitors ; Cell Nucleus ; metabolism ; Cells, Cultured ; Cisplatin ; administration & dosage ; pharmacology ; Cytosol ; metabolism ; Dose-Response Relationship, Drug ; Drug Synergism ; Epithelial Cells ; cytology ; metabolism ; Humans ; Kidney Tubules ; cytology ; Protein Transport ; RNA Interference ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; genetics

BACKGROUND: Human telomerase reverse transcriptase (hTERT) is a catalytic enzyme that is required for telomerase activity (TA) and cancer progression. Telomerase inhibition or inactivation increases cellular sensitivity to UV irradiation, DNA-damaging agents, the tyrosine kinase inhibitor, imatinib, and pharmacological inhibitors, such as BIBR1532. hTERT is associated with apoptosis. Some patients show drug-resistance during anti-cancer drug treatment and the cancer cell acquire anti-apoptotic mechanism. Therefore, we attempted to study correlation between hTERT and drug-resistance. METHODS: To study the correlation between protein level and activity of hTERT and drug-resistance, Western blotting and telomerase repeat amplification protocol (TRAP) assays were performed. To investigate whether hTERT contributes to drug resistance in tumor cells, we transiently decreased hTERT levels using small interfering RNA (siRNA) in T24/R2 cells. RESULTS: hTERT knockdown increased Bax translocation into the mitochondria and cytochrome C release into the cytosol. Caspase inhibitors, especially Z-VAD-FMK, rescued this phenomenon, suggesting that the stability or expression of hTERT might be regulated by caspase activity. CONCLUSIONS: These data suggest that hTERT might be a target molecule for drug-resistant tumor therapy.
Amino Acid Chloromethyl Ketones/pharmacology ; Antineoplastic Agents/*pharmacology ; Caspases/antagonists & inhibitors/metabolism ; Cell Line, Tumor ; Cisplatin/*pharmacology ; Cysteine Proteinase Inhibitors/pharmacology ; Cytochrome c Group/metabolism ; Drug Resistance, Neoplasm/genetics ; Humans ; Neoplasms/therapy ; RNA, Small Interfering ; Telomerase/*antagonists & inhibitors/genetics/metabolism ; bcl-2-Associated X Protein/metabolism

To test the hypothesis that exogenous purified angiotensin II (ANG) might cause apoptosis of alveolar epithelial cells (AECs) and acute lung injury, male Wistar rats were intratracheally instilled with purified ANG (10 mumol/L), ANG plus the caspase inhibitor ZVAD-fmk (60 mumol/L), ANG plus the ANG receptor AT1 antagonist losartan (LOS, 100 mumol/L) or sterile phosphate-buffered saline (PBS) vehicle alone. Six or 20 h later, the lungs were lavaged in situ for determination of bronchoalveolar lavage (BAL) fluid content of hemoglobin (Hb) and fluorescent (BODIPY)-albumin, a bolus of which was injected intravenously 15 min prior to BAL. Terminal deoxynucleotidyl transferase-mediated nick-end labeling (TUNEL) revealed that instillation of ANG, but not PBS alone, increased labeling of fragmented DNA in bronchiolar epithelial cells and in AECs (P<0.05) at 6 h post-ANG. Increased TUNEL was abrogated by concurrent instillation of ZVAD-fmk or LOS. Significant increased numbers of caspase-positive cells were observed by anti-caspase 3 immunolabeling after instillation of ANG (P<0.01); the same doses of LOS or ZVAD-fmk that blocked TUNEL also blocked the activation of caspase 3 (P<0.01). Intratracheal instillation of ANG also remarkably increased BAL BODIPY-albumin (P< 0.01) and Hb (P<0.05), both of which were eliminated by ZVAD-fmk or LOS. These data indicate that exposure of AECs to ANG in vivo is sufficient to induce apoptosis and alveolar epithelial barrier injury mediated by ANG receptor AT1.
Amino Acid Chloromethyl Ketones ; pharmacology ; Angiotensin II ; adverse effects ; Angiotensin II Type 1 Receptor Blockers ; pharmacology ; Animals ; Apoptosis ; Caspase 3 ; metabolism ; Caspase Inhibitors ; pharmacology ; Epithelial Cells ; pathology ; Losartan ; pharmacology ; Lung Injury ; chemically induced ; pathology ; Male ; Rats ; Rats, Wistar ; Receptor, Angiotensin, Type 1 ; metabolism

OBJECTIVETo study the molecular mechanism of TAp63gamma-induced cell apoptosis.

METHODSTranscription and protein expression of apoptosis inducing factor and p63 were investigated by immunohistochemistry and RT-PCR in human esophageal squamous carcinoma cell line EC9706 respectively. Twenty-four hours after transfection with pcDNA3.1-TAp63gamma, the apoptosis and translocation of apoptosis inducing factor in EC9706 cells were studied by flow cytometry, laser confocal microscopy and mitochondrial/cytosol/nuclear extraction analysis respectively. Down-regulation of apoptosis inducing factor protein was achieved by RNAi and pretreatment with caspase inhibitor zVAD.fmk of EC9706 cells.

RESULTSPresence of protein expressions of apoptosis inducing factor and absence of TAp63gamma was observed in the cytoplasm of untransfected cells. RT-PCR verified the subtype of p63 in EC9706 cells was DeltaNp63. After 24 hours of transfection, both nuclear and cytoplasmic expression of apoptosis inducing factor protein were observed in cells transfected with TAp63gamma and p53 expression vectors, but not in cells transfected with control vector. Cell apoptosis rates were 1.37%, 13.64%, 4.52%, 4.03% and 1.91% in the pcDNA3.1 transfection group, pcDNA3.1-TAp63gamma transfection group, apoptosis inducing factor siRNA and pcDNA3.1-TAp63gamma transfection group, zVAD.fmk treatment group, and the group receiving apoptosis inducing factor siRNA, plus zVAD.fmk treatment and pcDNA3.1-TAp63gamma transfection, respectively.

CONCLUSIONSApoptosis inducing factor of EC9706 cells is released from mitochondria into both the cytoplasm and nucleus during TAp63gamma induced apoptosis. Down-regulation of apoptosis inducing factor inhibits TAp63gamma-induced apoptosis. Overall, TAp63gamma-induced apoptosis is dependent on the expression of apoptosis inducing factor and caspase.

Amino Acid Chloromethyl Ketones ; pharmacology ; Apoptosis ; Apoptosis Inducing Factor ; genetics ; metabolism ; Carcinoma, Squamous Cell ; metabolism ; pathology ; Caspase Inhibitors ; Cell Line, Tumor ; Cell Nucleus ; metabolism ; Cytoplasm ; metabolism ; Down-Regulation ; Esophageal Neoplasms ; metabolism ; pathology ; Humans ; Mitochondria ; metabolism ; Plasmids ; Protein Transport ; RNA Interference ; RNA, Small Interfering ; genetics ; Trans-Activators ; genetics ; metabolism ; Transcription Factors ; Transfection ; Tumor Suppressor Proteins ; genetics ; metabolism

Although enediyne antibiotic lidamycin ( LDM) is a potent inducer of apoptosis, the underlying mechanisms of its apoptotic functions remain to be explored. Here, we aim to elucidate its possible mechanisms in mitochondria initiated apoptotic pathway involved in human BEL-7402 and MCF-7 cells. Cytochrome c released from mitchondria to cytosol fraction was detected by Western blotting. p53 and Bax, Bcl-2 expressions were detected by Western blotting and RT-PCR. MTT assay was used to detect cytotoxicity of LDM with or without caspase inhibitor z-VAD-fmk. After the BEL-7402 cells were exposed to 0. 1 micromol x L(-1) LDM within 6 h, the increase of cytochrome c in the cytosol and decrease in the mitochondria were observed when compared with untreated cells. The expression of Bax, an important proapoptotic member of the Bcl-2 family, increased gradually in the BEL-7402 cells after exposure to LDM of 0. 1 micromol x L (-1) for 2, 6, and 9 h, separately, while Bcl-2 increased at 2 and 6 h, and decreased at 9 h after LDM treatment. Enhanced protein expressions were parallel with respective increased mRNA level for Bax only, but not p53. Caspase inhibitor may inhibit partially the killing effects induced by LDM. Therefore we conclude that the rapid activation of mitochondrial pathway induced by LDM in tumor cells might contribute to its highly potent cytotoxicities.
Amino Acid Chloromethyl Ketones ; pharmacology ; Aminoglycosides ; pharmacology ; Antibiotics, Antineoplastic ; pharmacology ; Apoptosis ; drug effects ; Blotting, Western ; Caspase Inhibitors ; Caspases ; metabolism ; Cell Line, Tumor ; Cytochromes c ; metabolism ; Cytosol ; drug effects ; metabolism ; Enediynes ; pharmacology ; Humans ; Membrane Potential, Mitochondrial ; drug effects ; Mitochondria ; drug effects ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; drug effects ; Tumor Suppressor Protein p53 ; biosynthesis ; genetics ; bcl-2-Associated X Protein ; biosynthesis ; genetics

In a preliminary study, we found that benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethylketone (zVAD- fmk), unlike Boc-aspartyl(OMe)-fluoromethylketone (BocD-fmk), at usual dosage could not prevent genistein-induced apoptosis of p815 mastocytoma cells. This study was undertaken to reveal the mechanism underlying the incapability of zVAD-fmk in preventing this type of apoptosis. We observed that 14-3-3 protein level was reduced in genistein-treated cells and that BocD-fmk but not zVAD-fmk prevented the reduction of 14-3-3 protein level and the release of Bad from 14-3-3. We also demonstrated that truncated Bad to Bcl-xL interaction in genistein- treated cells was prevented by BocD-fmk but not by zVAD-fmk treatment. Our data indicate that BocD- fmk, compared to zVAD-fmk, has a certain preference for inhibiting 14-3-3/Bad signalling pathway. We also elucidated that this differential efficacy of BocD-fmk and zVAD-fmk resulted from the different effect in inhibiting caspase-6 and that co-treatment of zVAD-fmk and caspase-6 specific inhibitor substantially prevented genistein-induced apoptosis. Our data shows that caspase-6 plays a role on Bad/14-3-3 pathway in genistein-induced apoptosis of p815 cells, and that the usual dose of zVAD-fmk, in contrast to BocD-fmk, did not prevent caspase-6 acting on 14-3-3/Bad-mediated event.
bcl-Associated Death Protein/*metabolism ; *Signal Transduction/drug effects ; Mitochondria/drug effects ; Mice ; Mastocytoma ; Hydrocarbons, Fluorinated/*pharmacology ; Genistein/pharmacology ; Enzyme Inhibitors/*pharmacology ; Cell Line, Tumor ; Caspase 6/antagonists & inhibitors/*metabolism ; Benzyl Compounds/*pharmacology ; Apoptosis/*drug effects ; Animals ; Amino Acid Chloromethyl Ketones/pharmacology ; 14-3-3 Proteins/*metabolism