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Objective: The aim of this study was to explore the influence of micro ribonucleic acid (miR)-29 on neuronal apoptosis in rats with cerebral infarction by regulating the protein kinase B (Akt) signaling pathway., Materials and Methods: A total of 36 Sprague-Dawley rats were randomly divided into three groups, including: Sham group (n=12), Model group (n=12), and Inhibitor group (n=12). Common carotid artery, external carotid artery, and internal carotid artery were only exposed in the Sham group. However, the ischemia-reperfusion model was established by the suture method in the other two groups. After modeling, artificial cerebrospinal fluid was injected into the lateral ventricle in the rats of the Sham and Model groups. Similarly, miR-29 inhibitor was injected into the lateral ventricle in the rats of the Inhibitor group. At 24 h postoperatively, the sampling was performed. Zea-Longa score was used to evaluate the neurological deficit of rats. Meanwhile, the expressions of B-cell lymphoma 2 (Bcl-2) and Bcl-2 associated X protein (Bax) in cerebral tissues were detected via immunohistochemistry. The protein expression levels of Akt and phosphorylated Akt (p-Akt) were determined using Western blotting. Furthermore, the expression of miR-29 and cell apoptosis were detected via quantitative Polymerase Chain Reaction (qPCR) and terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) assay, respectively., Results: Compared with Sham group, Model, and Inhibitor groups had substantially raised the Zea-Longa scores (p<0.05). The Zea-Longa score in the Model group was markedly lower than that of the Inhibitor group (p<0.05). The positive expression level of Bax was remarkably upregulated (p<0.05). However, the positive expression level of Bcl-2 declined dramatically in both Model group and Inhibitor group when compared with the Sham group (p<0.05). Besides, the Model group exhibited significantly lower positive expression level of Bax and higher positive expression level of Bcl-2 than the Inhibitor group (p<0.05). The relative protein expression level of p-Akt markedly increased in the Model and Inhibitor groups when compared with the Sham group (p<0.05). However, it was considerably higher in the Model group than that of the Inhibitor group (p<0.05). In comparison with the Sham group, both Model group and Inhibitor group exerted substantially elevated expression level of miR-29 (p<0.05). The relative expression level of miR-29 in the Model group was significantly upregulated when compared with the Inhibitor group (p<0.05). The apoptosis rate of cells in both Model group and Inhibitor group was markedly higher than that of the Sham group (p<0.05). Furthermore, the Model group showed remarkably lower apoptosis rate than the Inhibitor group (p<0.05)., Conclusions: MiR-29 inhibits neuronal apoptosis in cerebral infarction rats by upregulating the Akt signaling pathway, thereby serving as a protector.

Diabetic cardiomyopathy is mediated by multiple molecular mechanisms including endoplasmic reticulum (ER) stress. Curcumin, a phenolic compound, has cytoprotective properties, but its potential protective action against diabetic cardiomyopathy and the related molecular mechanisms are not fully elucidated. In this study, we evaluated the effects of curcumin on cell viability and apoptosis in palmitic acid (PA)-treated H9C2 cardiomyocytes and investigated the signaling pathways involved. Treatment with PA reduced cell viability, induced apoptosis, enhanced apoptosis-related protein expression (Caspase 3 and BCL-2 associated X protein (BAX)), and activated ER stress marker protein expression (glucose-regulated protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP)). Curcumin attenuated PA-induced reduction in cell viability and activation of apoptosis, Caspase 3 activity, BAX, CHOP, and GRP78 expression. 4-Phenylbutyric acid (4-PBA) attenuated the PA-induced effects on cell viability and apoptosis, similar to curcumin. Both curcumin and 4-PBA also attenuated PA-induced increase in ER stress protein (CHOP and GRP78) expression. Curcumin also protected against cytotoxicity, apoptosis, and ER stress induced by thapsigargin. These findings indicate that PA triggers apoptosis in H9C2 cells via ER stress pathways and curcumin protects against this phenomenon.

Objective: Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia (AML), as standing out for its distinguished sensitivity to all-trans retinoic acid and arsenic trioxide (ATO, As2O3). The As2O3-mediated degradation of PML-RARA (promyelocytic leukemia-retinoic acid receptor-α) oncoprotein via the proteasome pathway appears to be critical for such distinguished sensitivity., Materials and Methods: The present study was to evaluate the influence by chloroquine (CQ), an inhibitor to the release of lysosomal enzymes, on the sensitivity of APL cells to As2O3. APL-derived NB4 cell line was treated with As2O3 or/and CQ in vitro. Then, the cell viability, the induction of apoptosis, and autophagy were examined with MTT assay, with TUNEL staining or with enhanced green fluorescence protein (EGFP)-light Chain 3 (LC3) reporter. The apoptosis- or autophagy-associated proteins were quantified with Western blotting assay., Results: Our results demonstrated that the As2O3 treatment promoted either apoptosis or autophagy in APL NB4 cells and upregulated both apoptosis- and autophagy-associated proteins. However, additional CQ treatment deteriorated the As2O3-induced NB4 cell apoptosis, whereas aggravated the As2O3-induced accumulation of acidic vesicular organelles (AVOs) and blocked the lysosomal degradation in NB4 cells., Conclusions: Chloroquine aggravates the arsenic trioxide-induced apoptosis of APL NB4 cells via inhibiting lysosomal degradation in vitro. It implies that chloroquine might be adjuvant to sensitize APL cells to arsenic trioxide.

Objective: To investigate the effect of miR-524 on the proliferation of thyroid cancer and its underlying mechanism., Patients and Methods: MiR-524 expression levels in thyroid cancer samples and para-cancer tissues were tested by quantitative Real-time polymerase chain reaction (qRT-PCR). Cells proliferative ability and apoptosis were evaluated through methyl thiazolyl tetrazolium (MTT) and apoptosis assays, respectively. Luciferase reporter assay was used to confirm the regulatory mechanism., Results: MiR-524 expression was reduced in thyroid cancer specimen (p<0.05). Up-regulated miR-524 expression inhibited the proliferative ability and enhanced cell apoptosis of thyroid cancer cells. SPAG9 was a target gene of miR-524, and was reversely regulated by miR-524., Conclusions: MiR-524 represses thyroid cancer cell proliferation and induces cell apoptosis via targeting SPAG9.

Objective: The effects of DNA methyltransferase (DNMT) inhibitor RG108 on the proliferation and apoptosis of endometrial cancer was investigated, and whether its mechanism was related to the inhibition of DNMT3B, thereby affecting the human mutL homolog 1 (hMLH1) methylation status and its expression, was further studied., Materials and Methods: Culture of human endometrial cancer Ishikawa cell lines: cells grew adhering to the wall in Roswell Park Memorial Institute-1640 (RPMI-1640) medium (supplemented with 10% fetal bovine serum (FBS) and 2 mM L-glutamic acid). After the cells were treated with RG108, the changes in cell viability were detected via methyl thiazolyl tetrazolium (MTT) assay. The effect of RG108 on cell cycle was detected via flow cytometry, and its effect on cell apoptosis was detected via flow cytometry and TUNEL. Moreover, the methylation status of hMLH1gene in endometrial cancer cells was detected via methylation specific-PCR (MSP), and the changes in DNMT3Band hMLH1 expressions were detected via RT-PCR and Western blotting, respectively., Results: MTT results showed that RG108 inhibited the cell viability in a dose-dependent and time-dependent manner. Flow cytometry revealed that RG108 blocked the cell cycle in G2/M phase and promoted the apoptosis, and TUNEL assay further proved that RG108 promoted the apoptosis. It was found in the detection via MSP that the methylated hMLH1 gene was significantly reduced after 72 h of treatment with RG108. Besides, RT-PCR and Western blotting showed that RG108 inhibited the DNMT3B expression and activated the hMLH1 expression., Conclusions: The demethylation drug RG108 can significantly inhibit the proliferation of endometrial cancer cells, block the cell cycle in the G2/M phase and induce the cell apoptosis, which is a new candidate drug in the treatment of endometrial cancer. RG108 realizes the hMLH1 demethylation and increases the hMLH1 expression through inhibiting the expression of DNMT3B.

Background: Human airway smooth muscle cells (ASMCs) may have a pro-inflammatory role through the release of inflammatory mediators. Increasing evidence indicates that human β-defensins (HBDs) are related to pathogenesis of asthma., Objectives: To examine the plasma level of HBD-1, HBD-2 and HBD-3 in asthmatic patients and the expression of their mouse orthologues in the lung tissue of a mouse model of chronic severe asthma. Further to investigate the effect of HBD-3 on the release of the pro-inflammatory cytokine IL-8 and to explore the mechanisms., Methods: The plasma levels of HBD-1, HBD-2 and HBD-3 from 34 healthy controls and 25 asthmatic patients were determined by ELISA. The expression of mouse β-defensins MBD-1, MBD-3 and MBD-14 in the lung tissue of asthmatic mice was detected by Western blot. The ASMCs were cultured with HBD-3 for 24 hour, and then the supernatant level of IL-8 was evaluated by ELISA and the cell viability was examined by WST-1 assay. The signalling pathway was investigated with blocking antibodies or pharmacological inhibitors., Results: The plasma levels of HBD-1 and HBD-3 were elevated in asthmatic patients, and the expression of MBD-14, the mouse orthologue for HBD-3, was increased in asthmatic mice. HBD-3-induced IL-8 production in a CCR6 receptor-specific manner and was dependent on multiple signalling pathways. Moreover, HBD-3-induced cell apoptosis concurrently, which was dependent on the ERK1/2 MAPK pathway. Mitochondrial ROS regulated both HBD-3-induced IL-8 production and cell apoptosis., Conclusions and Clinical Relevance: These observations provide clear evidence of an important new mechanism for the promotion of airway inflammation and tissue remodelling with potential relevance for the treatment of asthma., (© 2017 John Wiley & Sons Ltd.)

Esophageal squamous cell carcinoma (ESCC) is one of the major causes of cancer death worldwide, especially in Eastern Asia. Due to the poor prognosis, it is necessary to further dissect the underlying mechanisms and explore therapeutic targets of ESCC. Recently, studies show that long noncoding RNAs (lncRNAs) have critical roles in diverse biological processes, including tumorigenesis. Increasing evidence indicates that some lncRNAs are widely involved in the development and progression of ESCC, such as HOTAIR, SPRY4-IT1 and POU3F3. An emerging lncRNA, tissue differentiation-inducing nonprotein coding RNA (TINCR), has been studied in human cutaneous squamous cell carcinoma and has critical biological function, but its role in ESCC remains unknown. Here, we evaluated the expression profile of TINCR and its biological function in ESCC. In a cohort of 56 patients, TINCR was significantly overexpressed in ESCC tissues compared with paired adjacent normal tissues. Further, in vitro silencing TINCR via small interfering RNA (siRNA) inhibited the proliferation, migration and invasion of ESCC cells. Meantime, siRNA treatment induced apoptosis and blocked the progression of cell cycle. Taken together, our study suggests that TINCR promotes proliferation, migration and invasion of ESCC cells, acting as a potential oncogene of ESCC., (© 2016 International Society for Diseases of the Esophagus.)

ic inflammatory diseases, including OLP, involves in the activation of the nuclear factor-kappa B (NF-κB) signaling pathway. Baicalein (BAI) is an alcohol soluble flavonoid known for its anti-inflammatory effect. However, its effectiveness on keratinocytes in OLP remains unclear. In the present study, we examined inflammation in oral mucosa tissue from OLP patients. Hematoxylin and eosin staining showed denser subepithelial lymphocytes infiltration compared to the normal oral mucosa epithelium. TNF-α and IL-6 were up-regulated in oral mucosa tissue of OLP patients. We next stimulated humans keratinocytes (HaCaT cells) with lipopolysaccharide (LPS) to create an inflammatory environment like that in the OLP tissue and assessed the effect of BAI on OLP and NF-κB signaling pathways. Our results showed that BAI treatment inhibited the level of TNF-α and IL-6 induced by LPS. However, the cells apoptosis was promoted after BAI treatment. Furthermore, BAI not only inhibited LPS-induced p38 MAPK and ERK1/2 phosphorylation, but also NF-κB activation by reducing IκBα phosphorylation and the nuclear translocation of NFκB-p65 and NFκB-p50 from cytoplasm to nucleus in keratinocytes. Our findings suggest that BAI inhibits the production of inflammatory cytokines by negatively regulating the NF-κB signaling pathway under LPS simulation in HaCaT cells.

This study aims to research the effect of dihydroartemisinin on the proliferation, metastasis and apoptosis in human osteosarcoma cells 143B and the underlying mechanism. This study designed five groups for experiment and control, using dimethylsulfoxide (DMSO), and docosahexaenoic acid (DHA) at concentrations of 15, 25, 35 μmol.L-1 respectively. Experiments including methyl thiazolyl tetrazolium (MTT) assay, clone formation assay, Hoechst 33258 staining assay, luciferase reporter plasmid assay, Western blot and scratch test were carried out. In addition, SPSS 18.0 software from IBM was used for statistical analysis and all the data obtained from the experiments were expressed as mean ± SD, and variance was used to compare the difference between the groups. DHA is proved to be able to inhibit the proliferation and metastasis of osteosarcoma cells, as well as leaving a positive effect on apoptosis in the cytomorphosis. It achieves regulation over the human osteosarcoma cells by keeping the expression of related protein under control.

The inhibitor of apoptosis family member livin is expressed in several types of cancer but not in most benign tissues, and it has been considered to be a poor prognostic mark in various malignancies. However, livin expression and its prognostic relevance have not been evaluated in colorectal adenoma-carcinoma sequence. In this study, we analyzed the difference of livin expression among normal mucosa, adenoma, and adenocarcinoma and investigated the relationship of livin expression in carcinomas with clinicopathological variables using immunohistochemistry and real-time reverse transcription-PCR. We observed that the expression of livin protein was mainly present on base of colorectal crypts in adenoma and throughout the epithelium in carcinoma, whereas did not present in accompanying normal mucosa, and the expression of livin messenger RNA (mRNA) in adenocarcinomas was significantly higher than in adenomas and in normal mucosa (P = 0.001, respectively), whereas, compared with normal mucosa, the expression level of livin mRNA was up-regulated in adenomas but no significant difference (P = 0.196). We also found that the expression levels of livin mRNA in rectal cancer was significantly higher than those in colonic cancer, and livin mRNA expression was strongly related to colorectal cancer invasive depth but not to clinical tumor stage, differentiation, lymph node metastasis, tumor morphological category and pathological type, and patient's age and gender. These findings support the possibility that the livin gene may play a role in colorectal tumorigenesis, and increased expression of livin mRNA may serve as a new target for colorectal cancer treatment.

Melanoma has traditionally been viewed as a radioresistant cancer. However, recent studies suggest that under certain clinical circumstances, radiotherapy may play a significant role in the treatment of melanoma. Previous studies have demonstrated that telomere length is a hallmark of radiosensitivity. The newly discovered mammalian CTC1‑STN1-TEN1 (CST) complex has been demonstrated to be an important telomere maintenance factor. In this study, by establishing a radiosensitive/radioresistant human melanoma cell model, MDA-MB-435/MDA-MB‑435R, we aimed to investigate the association of CTC1 expression with radiosensitivity in human melanoma cell lines, and to elucidate the possible underlying mechanisms. We found that CTC1 mRNA and protein levels were markedly increased in the MDA-MB‑435R cells compared with the MDA-MB‑435 cells. Moreover, the downregulation of CTC1 enhanced radiosensitivity, induced DNA damage and promoted telomere shortening and apoptosis in both cell lines. Taken together, our findings suggest that CTC1 increases the radioresistance of human melanoma cells by inhibiting telomere shortening and apoptosis. Thus, CTC1 may be an attractive target gene for the treatment of human melanoma.

The objectives were to determine the effects of cumulus cells (CC) on porcine oocyte maturation in vitro (IVM) after heat shock (HS). Treated oocytes were cultured at 39 degrees C for 20h, followed by HS treatment (42 degrees C for 1h), and then matured in vitro for 23h. The CC were removed before maturation (H1), after HS (H2), or after maturation (H3). Control oocytes were continuously cultured under the same conditions and CC were similarly removed before maturation (C1), after 21h of IVM (C2), and after maturation (C3). Maturation rates were affected by HS (P<0.01) and by an interaction between HS and CC (P<0.01). A significant decrease in maturation rate only occurred when CC were not removed from cumulus oocyte complexes during IVM after HS (H3, 39.2+/-5.7% versus C3, 78.2+/-8.2%, P<0.01). Mature oocytes in all treatment groups were electrically activated and cultured for 8 d in NCSU23. Blastocyst rates in group H1 (7.2+/-3.5%) and C1 (6.3+/-3.1%) were lower than in other groups (H2, 21.4+/-4.4%, C2, 20.5+/-7.0%, H3, 23.1+/-2.0%, C3, 24.3+/-3.1%, P<0.05). Damaged DNA was detected in CC by a comet assay at 0h after HS (60.8+/-12.5% compared with 9.2+/-2.2% in control, P<0.05); in HS groups, both DNA damage (comet assay, 74.9+/-6.3% compared with 10.0+/-2.1% in control) and apoptosis (TUNEL assay, 21.6+/-1.6% compared with 5.6+/-0.6% in control) in CC were increased (P<0.05) at 44h of maturation. In conclusion, heat shock (42 degrees C for 1h) during IVM induced DNA damage and apoptosis of porcine CC; furthermore, apoptotic CC may contribute to maturation failure of oocytes in vitro.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent with the capability of inducing apoptosis specifically in tumor cells. However, cancer cells of many cancer types developed TRAIL resistance, limiting the applications of TRAIL in cancer therapies. We show here that p68 acquires a double tyrosine phosphorylation at Y593 and Y595 in TRAIL-resistant T98G glioblastoma cells. The double phosphorylations are induced by platelet-derived growth factor autocrine loop. The double phosphorylation mediates resistance to TRAIL-induced apoptosis. Our data suggest that the phosphorylated p68 protects the cells from programmed cell death by preventing procaspase-8 from proteolytic cleavage. The double-phosphorylated p68 may also confer apoptosis resistance by upregulation of X-chromosome-linked inhibitor apoptosis protein-associated factor 1. In addition, exogenous expression of p68 mutant that carries mutations at the phosphorylation sites (Y593/595F) dramatically sensitizes TRAIL-resistant cells to TRAIL-induced apoptosis, suggesting a potential therapeutic strategy to overcome TRAIL resistance.

Acetylcholinesterase (AChE) plays a key role in terminating neurotransmission at cholinergic synapses. AChE is also found in tissues devoid of cholinergic responses, indicating potential functions beyond neurotransmission. It has been suggested that AChE may participate in development, differentiation, and pathogenic processes such as Alzheimer's disease and tumorigenesis. We examined AChE expression in a number of cell lines upon induction of apoptosis by various stimuli. AChE is induced in all apoptotic cells examined as determined by cytochemical staining, immunological analysis, affinity chromatography purification, and molecular cloning. The AChE protein was found in the cytoplasm at the initiation of apoptosis and then in the nucleus or apoptotic bodies upon commitment to cell death. Sequence analysis revealed that AChE expressed in apoptotic cells is identical to the synapse type AChE. Pharmacological inhibitors of AChE prevented apoptosis. Furthermore, blocking the expression of AChE with antisense inhibited apoptosis. Therefore, our studies demonstrate that AChE is potentially a marker and a regulator of apoptosis.

Purpose: Cantharidin, a natural toxin, is the active substance of mylabris and has antitumor effects in man. Norcantharidin, the demethylated analogue of cantharidin, has been used in the treatment of patients with primary hepatoma and those with leukopenia in China. The present study was designed to investigate whether norcantharidin exerts cytotoxic activity against colorectal cancer cells by inducing apoptosis and to examine the possible mechanism in the phenomenon., Methods: Inhibition of proliferation of norcantharidin on Colo205, HT-29, and SW480 colorectal cancer cells was determined by the trypan blue dye exclusion test. Apoptosis of norcantharidin-treated cells was determined by morphological analysis, agarose gel DNA electrophoresis, and quantitated by flow cytometry after staining with propidium iodide. Cell cycle and the cell surface expression of the CD95/CD95 ligand were evaluated by flow cytometry. Caspase 8-like protease and protein phosphatase 1 and 2A activities were also analyzed., Results: Treatment with norcantharidin of colorectal cancer cells not only inhibited cell proliferation, but also induced apoptosis. Norcantharidin induced apoptosis mainly in two phases: rapid apoptosis in S-phase cells and delayed apoptosis in G2/M arrested cells. Treatment with norcantharidin resulted in an upregulation of the CD95 receptor and CD95 ligand on the cell surface. Furthermore, stimulation with anti-CD95 monoclonal antibody (mAb) resulted in further induction of apoptosis after treatment with norcantharidin. In addition, the apoptosis-inducing effect of norcantharidin was almost completely inhibited by anti-CD95 ligand mAb. Norcantharidin-treated cells showed the activation of caspase 8. Both zVAD-FMK (a broad range caspase inhibitor) and IETD-FMK (a caspase-8 inhibitor) showed apparent inhibition of the apoptosis-inducing effect. Norcantharidin did not show an inhibitory effect on protein phosphatase., Conclusions: These results suggest that norcantharidin triggers apoptosis in colorectal cancer cell lines via the activation of the CD95 receptor/ligand system, and that this agent may be useful for developing new therapeutic regimens for the treatment of colorectal carcinoma.

Owing at least in part to oxysterol components that can induce apoptosis, oxidized LDL (oxLDL) is cytotoxic to mammalian cells with receptors that can internalize it. Vascular cells possess such receptors, and it appears that the apoptotic response of vascular cells to the oxysterols borne by oxLDL is an important part of the atherogenic effects of oxLDL. Thus, an analysis of the signaling pathway of apoptotic induction by oxysterols is of value in understanding the development of atherosclerotic plaque. In a prior study, we demonstrated an induction of calcium ion flux into cells treated with 25-hydroxycholesterol (25-OHC) and showed that this response is essential for 25-OHC-induced apoptosis. One possible signal transduction pathway initiated by calcium ion fluxes is the activation of cytosolic phospholipase A2 (cPLA2). In the current study, we demonstrate that activation of cPLA2 does occur in both macrophages and fibroblasts treated with 25-OHC or oxLDL. Activation is evidenced by 25-OHC-induced relocalization of cPLA2 to the nuclear envelope and arachidonic acid release. Loss of cPLA2 activity, either through genetic knockout in mice, or by treatment with a cPLA2 inhibitor, results in an attenuation of arachidonic acid release as well as of the apoptotic response to oxLDL in peritoneal macrophages or to 25-OHC in cultured fibroblast and macrophage cell lines.

Objective: To explore the effect of apoptosis-associated gene bcl-2 overexpression on ethanol-induced apoptosis in hepatocellular carcinoma (HCC) cells., Methods: The plasmid of retrovirus expression vector pDOR-SB, which contains human bcl-2 cDNA, was transfected into a HCC cell line HCC-9204 cells whose bcl-2 protein expression is below detectable level. The expression of bcl-2 protein was detected by immunohistochemical ABC method. The cells were cloned continually until a monoclonal cell strain which expressed bcl-2 protein at a 100% positive rate was obtained, and the cells were detected with flow cytometry. After the above cells were treated with 6% ethanol for 6 h, the happening of apoptosis were detected by MTT assay, TUNEL assay and flow cytometry., Results: bcl-2 protein expression was detected in most of the cells which had been transfected with pDOR-SB, while it was bcl-2 protein negative in cells transfected with pDOR empty vector or non-transfected HCC-9204 cells. The obtained monoclonal cell strain expressed bcl-2 protein at a 100% positive rate under flow cytometer after being cloned 3 times in succession, and was named HCC-bcl-2. After being treated with 6% ethanol, the optical absorbance data of HCC-bcl-2 cells and non-transfected HCC-9204 cells detected by MTT assay were 0.519 +/- 0.053 and 0.366 +/- 0.046, respectively, the former was significantly higher than the latter (P < 0.01). Their TUNEL index was 0.387 and 0.613 respectively, and their sub-G1 apoptotic peak scale was 3.8% and 10.7% respectively, the former were all lower than the latter (P < 0.05)., Conclusion: Overexpression of bcl-2 protein can suppress ethanol-induced apoptosis in HCC-9204 hepatoma cells.

The non-essential amino acids L-serine (Ser) and glycine (Gly) have recently been shown to exhibit specific actions in the nervous system. In the present study, L-Ser and Gly promoted the survival of cultured rat cerebrocortical neurons in a concentration-dependent manner as revealed by Alamar blue assay and microtubule-associated protein-2 (MAP2) immunoblotting. The maximum effects of the amino acids were detected at the concentrations of 30-100 microM. L-Ser was more effective than Gly. D-Ser failed to promote neuronal survival. L-Ser and Gly upregulated expression of the anti-apoptotic gene product Bcl-w, while they did not affect the expression of Bcl-xL. The promotion of neuronal survival by L-Ser and Gly may be, at least in part, attributable to the upregulated Bcl-w.

We have previously shown that 25-hydroxycholesterol (25-OHC) treated CHO-K1 cells could be used as a model to investigate the signaling pathway of apoptosis induced by oxidized LDL in vascular cells. In the present study, we examine the execution phase of the apoptotic pathway in CHO-K1 cell death induced by 25-OHC. Oxysterol-induced apoptosis in CHO-K1 was accompanied by caspase activation and was preceded by mitochondrial cytochrome c release. The addition of a competitive caspase-3 inhibitor, Ac-DEVD-CHO, prevented 25-OHC-induced apoptotic cell death. Furthermore, immunoblot analysis showed that 25-OHC treatment induced the degradation of poly(ADP-ribose) polymerase (PARP)-a substrate for caspase 3 and a key enzyme involved in genome surveillance and DNA repair. Thus, we could demonstrate in CHO-K1 cells that 25-OHC activates the apoptotic machinery through induction of the release of cytochrome c from mitochodria into the cytosol and activation of a typical caspase cascade., (Copyright 2000 Academic Press.)

The mechanisms linking acinar cell apoptosis and ductal epithelial proliferation remain unknown. To determine the relationship between these events, pancreatic duct ligation (PDL) was performed on p53(+/+) and p53(-/-) mice. In mice bearing a wild-type p53 allele, PDL resulted in upregulation of p53 protein in both acinar cells and proliferating duct-like epithelium. In contrast, upregulation of Bcl-2 occurred only in duct-like epithelium. Both p21(WAF1/CIP1) and Bax were also upregulated in duct-ligated lobes. After PDL in p53(+/+) mice, acinar cells underwent widespread apoptosis, while duct-like epithelium underwent proliferative expansion. In the absence of p53, upregulation of p53 target genes and acinar cell apoptosis did not occur. The absence of acinar cell apoptosis in p53(-/-) mice also eliminated the proliferative response to duct ligation. These data demonstrate that PDL-induced acinar cell apoptosis is a p53-dependent event and suggest a direct link between acinar cell apoptosis and proliferation of duct-like epithelium in duct-ligated pancreas.

Objective: To investigate the expression of bax and bcl-2 in normal human articular chondrocytes and in osteoarthritic articular cartilage., Methods: The samples of articular cartilage were obtained from 9 patients and 6 normal subjects. Bax and bcl-2 mRNA were detected by reverse transcriptase/polymerase chain reaction (RT-PCR) and their expression proteins were analyzed immunohistochemically. TUNEL technique was used to study apoptosis in situ., Results: Bax and bcl-2 mRNA was detectable in chondrocytes of both osteoarthritic and normal cartilage. Bax mRNA of chondrocytes from patients with osteoarthritis (OA) was overexpressed compared with the normal controls (P < 0.01), and OA cartilage chondrocyte also expressed more bcl-2 mRNA than the controls (P < 0.05). There was no statistically significant difference of bax/bcl-2 between the two groups. Immunohistochemical staining demonstrated the same level of bax and bcl-2 proteins as their mRNA. A greater proportion of apoptotic chondrocytes were found in the OA cartilage than that in normal controls (4% - 14% versus 0 - 2%)., Conclusions: Our results suggested that chondrocyte apoptosis was co-regulated by both bax and bcl-2. The ratio of bax to bcl-2 may contribute not only to the lower percentage of apoptotic chondrocytes, but also to the chronic pathologic process in OA.

Oxidized low density lipoprotein (oxLDL) induces apoptosis in macrophages, smooth muscle cells, and endothelial cells. To elucidate the molecular mechanism of oxLDL-induced cytotoxicity and determine its tissue specificity, we have used Chinese hamster ovary (CHO)-K1 cells expressing human CD36 (CHO/CD36). Expression of CD36 rendered these cells susceptible to killing by oxLDL. This cytotoxicity was due to the induction of apoptosis. Therefore, CD36 expression is the only requirement for oxLDL-induced apoptosis. Oxysterols apparently mediate the cytotoxicity of oxLDL in macrophage foam cells and endothelial cells. 25-Hydroxycholesterol, at concentrations higher than 1 microg/ml, killed CHO-K1 cells, by apoptosis, in medium supplemented with serum as a source of cholesterol. These effects were not seen in a 25-hydroxycholesterol-resistant CHO/CD36 mutant (OX(R)), which was otherwise capable of undergoing apoptosis in response to staurosporine. This mutant was also resistant to killing by oxLDL, suggesting that oxysterols are at least partially responsible for the toxic effects of oxLDL. Oxysterol-induced apoptosis did not involve regulation of sterol regulatory element-binding protein proteolysis or the cholesterol biosynthetic pathway. 25-Hydroxycholesterol stimulated calcium uptake by CHO-K1 cells within 2 min after addition. Treatment of CHO or THP-1 (macrophage) cells with the calcium channel blocker nifedipine prevented 25-hydroxycholesterol induction of apoptosis. OX(R) showed no enhanced calcium uptake in response to 25-hydroxycholesterol.

Objective: To investigate the relationship of bcl-2 gene expression level in human gliomas with the malignant degree, cell proliferative activity and apoptosis of the tumors., Methods: The expression of bcl-2 mRNA, bcl-2 protein and proliferating cell antigen, and the apoptosis in sixty-nine human glioma specimens with different malignant grades were studied using in situ hybridization, in situ cell death detection (TUNEL method) and immunohistochemistry., Results: Of the 69 gliomas, 64 (92.8%) and 60 (87.0%) expressed bcl-2 mRNA and bcl-2 protein, respectively. The expression levels of bcl-2 mRNA and bcl-2 protein were correlated positively with each other (r(s) = 0.999, P < 0.01). The expression levels of bcl-2 mRNA and bcl-2 protein were both higher in WHO grade IV gliomas than in grade III gliomas, and the expression was lowest in grade I-II gliomas (P < 0.02 approximately 0.001). With the increase in the expression of bcl-2 protein, the cell proliferating activity increased and apoptosis decreased in the tumor cells. There was significant difference of cell proliferation and apoptosis between + + + group and + + group of bcl-2 protein expression (P < 0.05) as well as between both the former groups, and the negative and + group (P < 0.01) respectively., Conclusions: Over-expression of bcl-2 gene inhibits apoptosis of glioma cells, and the inhibitory intensity increases with the ascending of bcl-2 gene expression level in glioma cells. Both the decrease in apoptosis caused by bcl-2 gene over-expression and the excessive cell proliferation promoted by other gene abnormalities may result in unlimited cell accumulation, which may play an important role in the development and malignant progression of gliomas.

In order to study the effects of losartan on cardiomyocyte apoptosis following ischemia (0.5 h) and reperfusion (48 h) in vivo and bcl-2 and bax gene expression, TUNEL staining method, immunohistochemistry and in situ hybridization histochemistry (ISHH) were used to monitor the apoptotic cells, mRNA and protein of gene expression, respectively. Image processing system was used to quantitatively dispose the positive metric substance of both immunohistochemistry and ISHH through the average optical density (OD) value. The number of the apoptotic cells were 38 +/- 9 (control group), 0-1 (sham operation group) and 9 +/- 4 (losartan-treated group) in each visual field respectively with the difference among the groups being significant (P < 0.001). OD values of bcl-2 (ISHH) were 0.07425 +/- 0.02029 (control group), 0.05961 +/- 0.009932 (sham operation group) and 0.07619 +/- 0.01445 (losartan-treated group) respectively, while OD values of bcl-2 (immunohistochemistry) were 0.1374 +/- 0.01367 (control group), 0.08510 +/- 0.01862 (sham operation group) and 0.1252 +/- 0.02064 (losartan-treated group). bcl-2 gene expression was increased significantly in the control group and losartan-treated group as compared with sham operation group (P < 0.05). OD value of bax (immunohistochemistry) was 09727 +/- 0.02230 (control group), 0.06182 +/- 0.01430 (sham operation group) and 0.06213 +/- 0.01420 (losartan-treated group). bax gene expression was decreased very significantly in losartan-treated group and sham operation group as compared with control group (P < 0.001). Bcl-2/bax ratio was 1.413 (control group), 1.376 (sham operation group) and 2.016 (losartan-treated group) respectively. The results indicated that losartan might inhibit cardiomyocyte apoptosis following ischemia and reperfusion. The mechanism might be that bax gene expression was inhibited to increase bcl-2/bax ratio.

The regulation of apoptosis in mature CD4+ or CD8+ alphabeta+ T cells has been well studied. How the survival and death is regulated in peripheral CD4-CD8- (double negative, DN) alphabeta+ T cells remains unknown. Recent studies suggest that peripheral DN T cells may play an important role in the regulation of the immune responses mediated by CD4+ or CD8+ T cells. Here, we used immunosuppressive DN T cell clones to elucidate the mechanisms involved in the regulation of death and survival of alphabeta+ DN T cells. The DN T cell clones were generated from the spleen cells of 2C transgenic mice, which express the transgenic TCR specific for Ld and permanently accepted Ld+ skin allografts after pretransplant infusion of Ld+ lymphocytes. We report that 1) the mature DN T cells are highly resistant to TCR cross-linking-induced apoptosis in the presence of exogenous IL-4; 2) Fas/Fas-ligand and TNF-alpha/TNFR pathways do not play an apparent role in regulating apoptosis in DN T cells; 3) the DN T cells constitutively express a high level of Bcl-xL, but not Bcl-2; 4) both Bcl-xL and Bcl-2 are up-regulated following TCR-cross-linking; and 5) IL-4 stimulation significantly up-regulates Bcl-xL and c-Jun expression and leads to mitogen-activated protein kinase phosphorylation in DN T cells, which may contribute to the resistance to apoptosis in these T cells. Taken together, these results provide us with an insight into how mature DN T cells resist activation-induced apoptosis to provide a long-term suppressor function in vivo.

Objective: This study aimed to establish and characterize ectomesenchymal stem cells and further reveal the effects of all trans-retinoic acid (RA) on the biologic behaviors of these cells., Methods: Ectomesenchymal stem (EMS) cells of developing palatal processes were explanted from the palatal shelves of embryonic BALB/c mice. The characterization of EMS cells was accomplished by immunohistochemical analysis and growth curves. The action of RA on EMS cells was evaluated according to population doubling time and the terminal deoxyribonucleotidyl transferase dUTP nick end-labeling assay., Results: Primary culturing of EMS cells proceeded successfully. The results of immunohistochemistry showed that EMS cells stained neuron-specific enolase (+), S-100 (+), vimentin (+3), keratin (-), myoglobin (-) and factor VIII (-). The population doubling time of RA-treated EMS cells was much longer compared with nontreated EMS cells. RA also dramatically increased the number of apoptotic cells., Conclusion: Ectomesenchymal stem cells may be undifferentiated. RA inhibited their proliferation and induced apoptosis. The inhibition of growth and excess apoptosis may contribute to the formation of cleft lip/palate and other orofacial congenital malformations.

Apoptotic neuronal death is known to occur in the developing brain and in the mature brain of patients with ischemic and degenerative disorders. Although microglial cells are known to become activated in specific conditions, it has not been elucidated whether they enhance or prevent neuronal apoptosis. The present study was intended to observe how microglial cells are involved in neuronal death. When rat primary cortical neurons were incubated with a nitric oxide (NO) donor sodium nitroprusside (SNP; 300 microM) for 10 min, neuronal death occurred 12-16 hr later. The NO-induced neuronal death was inhibited by cycloheximide, and the SNP-treated neurons were characterized by nuclear fragmentation and intact cell membrane under electron microscopy. Agarose gel electrophoresis demonstrated DNA fragmentation of the SNP-treated neurons. Thus, the NO-induced neuronal death appeared to be apoptosis. When neurons were cocultured with rat primary microglial cells, the SNP treatment failed to induce the neuronal death. Because microglia-conditioned medium also prevented apoptotic neuronal death, microglial cells were considered to secrete antiapoptotic factors. The microglia-conditioned medium rescued neurons even when they were added to neuronal cultures after the SNP treatment, implying that the factors acted on neurons in a manner other than scavenging NO. Interleukin-3, interleukin-6, macrophage colony-stimulating factor, and basic fibroblast growth factor, which are known to be secreted by microglial cells, were not effective in preventing NO-induced neuronal death. Among microglia-derived substances, tumor necrosis factor alpha and plasminogen, which are heat-labile proteins, inhibited neuronal apoptosis. The neuroprotective action of the microglia-conditioned medium, however, still remained, even after it was heated. These findings suggest that microglial cells protect neurons against NO-induced lethal damage by secreting heat-labile and heat-stable neuroprotective factors in vitro.

The G2 cell cycle checkpoint protects cells from potentially lethal mitotic entry after DNA damage. This checkpoint involves inhibitory phosphorylation of Cdc2 at the tyrosine-15 (Y15) position, mediated in part by the Wee1 protein kinase. Recent evidence suggests that p53 may accelerate mitotic entry after DNA damage and that the override of the G2 checkpoint may play a role in the induction of apoptosis by p53. To determine the biochemical mechanism by which p53 inactivates the G2 checkpoint, the effects of p53 activation on Wee1 expression, Cdc2-Y15 phosphorylation, and cyclin B1-associated Cdc2 kinase activity were examined. Under conditions of either growth arrest or apoptosis, p53 activation resulted in the down-regulation of Wee1 expression and dephosphorylation of Cdc2. A parallel increase in cyclin B1/Cdc2 kinase activity was observed during p53-mediated apoptosis. Negative regulation of the Wee1 expression and Cdc2 phosphorylation by p53 was also evident in thymus tissue from p53+/+ mice but not from p53-/- mice. Inactivation of the G2 checkpoint may contribute to the tumor suppressor activity of p53.

A failure of normal apoptosis, often due to mutant p53, may contribute to the formation of a cancer and to its resistance to therapy. Mesothelioma, an asbestos-induced tumor, is highly resistant to therapy but generally expresses wild-type p53. We asked whether mesothelioma was resistant to apoptosis and whether resistance was associated with altered expression of the antiapoptotic protein Bcl-2 or proapoptotic protein Bax. We found that three mesothelioma cell lines (1 with wild-type p53) were highly resistant to apoptosis induced by oxidant stimuli (asbestos, H2O2) or nonoxidant stimuli (calcium ionophore) compared with primary cultured mesothelial cells. By immunostaining, one of these three lines expressed Bcl-2 but only during mitosis. By immunoblotting, 3 of 14 additional mesothelioma lines (9 of 14 with wild type p53) expressed Bcl-2 but all 14 of 14 expressed the proapoptotic Bax, giving a low ratio of Bcl-2 to Bax. We conclude that mesothelioma cell lines are resistant to apoptosis and that the failure in apoptosis is not explained by Bcl-2 but by other mechanisms that counteract the proapoptotic effect of Bax.

Annexin proteins specifically bind anionic phospholipids such as phosphatidylserine, which are normally confined to the cytoplasmic leaflet of cellular membranes. During programmed cell death, or apoptosis, this phospholipid asymmetry is lost, and anionic phospholipids are exposed on the extracellular leaflet of the plasma membrane where they are accessible to exogenously added, labeled annexins. Chemically [e.g., fluoroscein isothiocyanate (FITC)]-modified annexin V has been widely used to detect and enumerate apoptotic cells by flow cytometry. We prepared chimeric proteins containing green fluorescent protein (GFP) fused to annexin V. A chimera containing GFP fused to the C-terminus of annexin V was soluble and fluorescent, but was unable to bind phospholipids. In contrast, a chimera containing GFP fused to the N-terminus of annexin V specifically bound apoptotic cells. GFP-annexin V represents a sensitive and facile alternative to FITC-annexin V for studies of apoptosis.

Mesothelial cells, the progenitor cells of the asbestos-induced tumor mesothelioma, are particularly sensitive to the toxic effects of asbestos, although the molecular mechanisms by which asbestos induces injury in mesothelial cells are not known. We asked whether asbestos induced apoptosis in mesothelial cells and whether reactive oxygen species were important. Rabbit pleural mesothelial cells were exposed to crocidolite asbestos or control particles (1-10 micrograms/cm2) over 24 hr and evaluated for oligonucleosomal DNA fragmentation, loss of membrane phospholipid asymmetry, and nuclear condensation. Asbestos fibers, not control particles, induced apoptosis in mesothelial cells by all assays. Induction of apoptosis was dose dependent; crocidolite (5 micrograms/cm2) induced apoptosis (15.0 +/- 1.1%, mean +/- SE; n = 12) versus control particles (< 4%), as measured by appearance of nuclear condensation. Apoptosis induced by asbestos, but not by actinomycin D, was inhibited by extracellular catalase, superoxide dismutase in the presence of catalase, hypoxia (8% oxygen), deferoxamine, and 3-aminobenzamide (an inhibitor of the nuclear enzyme, poly(adenosine diphosphate-ribosyl) polymerase). We conclude that asbestos induces apoptosis in mesothelial cells via reactive oxygen species. We speculate that escape from this pathway could allow the abnormal survival of mesothelial cells with asbestos-induced mutations.

Mesothelial cells, the progenitor cell of the asbestos-induced tumor mesothelioma, are particularly sensitive to the toxic effects of asbestos, although the molecular mechanisms by which asbestos induces injury in mesothelial cells are not known. We asked whether asbestos induced apoptosis in mesothelial cells and whether reactive oxygen species were important. Pleural mesothelial cells (rabbit or human) were exposed to asbestos (crocidolite, amosite, or chrysotile) or control particles at moderate doses (1-10 microg/cm2) over 24 h and evaluated for oligonucleosomal DNA fragmentation, loss of membrane phospholipid asymmetry, and nuclear condensation. Asbestos fibers, not control particles, induced apoptosis in mesothelial cells by all assays and induction of apoptosis was dose dependent for all types of asbestos, with crocidolite (5 microg/cm2) inducing 15.0+/-1.1% (mean+/-SE; n = 12) apoptosis versus control particles < 4%. Apoptosis induced by asbestos, but not by actinomycin D, was inhibited by extracellular catalase, superoxide dismutase in the presence of catalase, hypoxia (8% oxygen), deferoxamine, 3-aminobenzamide [an inhibitor of poly(ADP-ribosyl) polymerase], and cytochalasin B. Only catalase and cytochalasin B decreased fiber uptake. We conclude that asbestos induces apoptosis in mesothelial cells via reactive oxygen species. Escape from this pathway could allow the abnormal survival of mesothelial cells with asbestos-induced mutations.

The product of apoptosis-suppressing oncoprotein bcl-2 can block apoptosis and result in the development of tumors. In this study, the expression of bcl-2 was observed in 40 cases of ameloblastomas by immunohistochemical staining. The results showed that the epithelium and reduced enamel epithelium of the enamel organ, the odontoblasts, basal cells of odontogenic cysts, normal oral epithelium and 90% (36/40) of ameloblastomas were positive for bcl-2, indicating that the expression of bcl-2 in odontogenic epithelium may be related to the degree of differentiation and proliferation of cells, the overexpression of bcl-2 may be associated with the development of ameloblastoma.