Expression Of Apoptosis-regulating Genes Research Articles

Expression of apoptosis-regulating genes in the rat prostate following botulinum toxin type a injection

BackgroundOnabotulinumtoxin A (OnabotA) injection has been investigated as a novel treatment for benign prostatic enlargement caused by benign prostatic hyperplasia. An OnabotA - induced volume reduction caused by sympathetic fibers impairment has been proposed as a potential mechanism of action. Our aim was to investigate the expression of apoptosis-regulating proteins in the rat prostate following OnabotA intraprostatic injection.MethodsAdult Wistar rats were injected in the ventral lobes of the prostate with 10 U of OnabotA or saline. A set of OnabotA-injected animals was further treated with 0.5 mg/kg of phenylephrine (PHE) subcutaneously daily. All animals were sacrificed after 1 week and had their prostates harvested. Immunohistochemical staining was performed for Bax, Bcl-xL and caspase-3 proteins and visualized by the avidin-biotin method. The optical density of the glandular cells was also determined, with measurement of differences between average optical densities for each group.ResultsSaline-treated animals showed intense epithelial staining for Bcl-xL and a faint labelling for both Bax and Caspase-3. OnabotA-treated rats showed a reduced epithelial staining of Bcl-xL and a consistently increased Bax and Caspase-3 staining when compared with saline-treated animals. PHE-treated animals showed a stronger Bcl-xL staining and reduced staining of both Bax and Caspase-3 when compared to the OnabotA group. Mean signal intensity measurements for each immunoreaction confirmed a significant decrease of the signal intensity for Bcl-xL and a significant increase of the signal intensity for Bax and Caspase 3 in OnabotA-injected animals when compared with the control group. In OnabotA+PHE treated animals mean signal intensity for Bcl-xL, Bax and Caspase 3 immunoreactions was identical to that of the control animals.ConclusionsThese results support the hypothesis that OnabotA activates apoptotic pathways in the rat prostate through a mechanism that involves sympathetic outflow impairment.

Antiapoptotic effect of angiotensin-II type-1 receptor blockade in renal tubular cells of hyperoxaluric rats

In this study, we investigated the protective effect of losartan as an AT1 receptor antagonist by evaluating the expression of apoptosis-regulatory genes that contribute to the progressive damage in the renal tubules of hyperoxaluric rats. Rats were divided into 4 groups of 10 each; control (C), ethylene glycol (EG), ethylene glycol + losartan (EG + L) and Losartan (L). For 4 weeks 0.8% EG, as a precursor for oxalate, was administered to EG and EG + L and losartan (300 mg/l) was administered to groups EG + L and L. Urine and blood samples were collected for biochemical determination. Bcl-2, bax, caspase-3 and TGF-beta 1 antibodies were used for immunohistochemistry. Apoptosis was determined by TUNEL method. A marked increase in urinary oxalate levels of the rats in EG and EG + L groups was found. In the EG group a diffuse amount of oxalate crystals into the tubular lumina and interstitium in the cortex was observed. In the EG group GBM thickening, interstitial fibrosis and tubular atrophy with infiltration of mononuclear cell findings reduced in the EG + L group were presented as well. In the EG group, immunoreactivity of TGF-beta 1 was increased in glomeruli and tubuli. In the EG + L group, immunoreactivity of TGF-beta 1 was decreased compared to the EG group. Bax expression increased in the renal tubules of EG group and reduced in the EG + L group comparing to the control. In the EG + L group, the immunoreactivity of bcl-2 was increased in glomeruli. In EG + L treated group, number of caspase-3 immunopositive cells were decreased compared to all groups (P < 0.01). Apoptotic cells were increased in the EG-treated group compared to the other groups. Decreased apoptotic cell number was observed in the EG + L compared to the EG group (P < 0.01). Our findings suggest that losartan may provide a beneficial effect against tubulointerstitial damage and decrease renal tubular apoptosis caused by hyperoxaluria.

Cell cycle and apoptosis regulatory gene expression in the bone marrow of patients with de novo myelodysplastic syndromes (MDS)

Deregulation of cell cycle and apoptosis pathways are known contributors to the pathogenesis of myelodysplastic syndromes (MDS). However, the underlying mechanisms are not fully clarified. The aim of our study was to examine mRNA expression levels of cell cycle and apoptosis regulatory genes, as well as the percentage of apoptotic and S phase cells and to correlate the findings with clinical characteristics and prognosis. Sixty patients with MDS, classified according to FAB (17 RA, five RARS, 19 RAEB, nine RAEBT, ten CMML) and WHO (ten RA, three RARS, seven RCMD, two RCMD-RS, 11 RAEBI, eight RAEBII, ten CMML, and nine AML) were included in the study. We found increased expression of anti-apoptotic bclxL and mcl1 genes and decreased expression of p21 gene in MDS patients. Moreover, we found increased expression of anti-apoptotic mcl1 gene in patients with higher than Intermediate-1 IPSS group. Multivariate analysis confirmed that combined expression of apoptotic caspases 8, 3, 6, 5, 2, 7, and Granzyme B was decreased in MDS patients. Regarding cell cycle regulatory genes expression, we demonstrated increased expression of cyclin D1 in patients with CMML Increased combined expression of cyclins B, C, D1, and D2 was found in patients with cytogenetic abnormalities. The two pathways seem to be interconnected as shown by the positive correlation between CDKs 1, 2, 4, p21 and the level of apoptosis and positive correlation between apoptotic caspase 3 expression and the percentage of S phase cells. In conclusion, our study showed altered expression of genes involved in apoptosis and cell cycle in MDS and increased expression of cyclin D1 in patients with CMML.

Combination treatment of malignant B cells using the anti-CD20 antibody rituximab and the anti-malarial artesunate

Chemotherapy of non-Hodgkin's lymphoma is frequently hampered by drug resistance. The monoclonal antibody rituximab specifically targets the CD20 antigen and sensitizes B-cell lymphoma cells to standard anticancer drugs. In the present investigation, we analyzed, whether a combination of rituximab and artesunate may act in a complementary manner and eventually synergize in tumor cell killing. Artesunate is an anti-malarial drug, which also exerts profound activity towards cancer cells. While rituximab alone was minimally cytotoxic, rituximab increased cytotoxicity to artesunate in Ramos cells. Artesunate induced apoptosis, induced Fas/CD95 expression and the formation of reactive oxygen species (ROS) and resulted in a breakdown of mitochondrial membrane potential. This argues for the involvement of both receptor-driven extrinsic and mitochondrial intrinsic routes of apoptosis. Rituximab increased Fas/CD95 expression and ROS formation and decreased mitochondrial membrane potential ultimately leading to increased apoptosis induced by artesunate. The transcription factors YY1 and Sp1 are upstream regulators of apoptosis by controlling the expression of apoptosis-regulating genes. YY1 and Sp1 were down-regulated and Fas/CD95 was up-regulated by rituximab and artesunate indicating that artesunate activated the Fas/CD95 pathway and that rituximab increased the susceptibility of tumor cells to artesunate-induced apoptosis. Furthermore, rituximab affected the expression of antioxidant genes. The antibody decreased artesunate-induced up-regulation of catalase expression and increased artesunate-induced down-regulation of glutathione S-transferase-phi expression. Manganese-dependent superoxide dismutase expression was not changed by artesunate. Antioxidant proteins may help to detoxify artesunate-induced ROS. Rituximab reversed the artesunate-induced expression changes of antioxidant genes and, hence, reduced the detoxification capacity of Ramos cells. The effects of rituximab on antioxidant genes represent a novel mechanism of rituximab for chemosensitization.

Expression of Apoptosis Regulatory Genes and Incidence of Apoptosis in Different Morphological Quality Groups of In Vitro-produced Bovine Pre-implantation Embryos

Apoptosis occurs during early development in both in vivo- and in vitro-produced embryos, and is considered as one of the causes of embryonic loss. The objectives of this study were, therefore, investigating stage-specific expression profiles of apoptosis regulatory genes in three quality groups of in vitro-produced bovine pre-implantation embryos; and analysing the relationship between cell number and DNA fragmentation with expressions of those genes. The relative abundance of mRNA of 9 pro- (Bax, caspase-9, Bcl-xs, P53, Caspase-3 and Fas) and anti- (Bcl-w and Mcl-1) apoptotic genes was analysed. Differential cell staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling were performed to analyse the variation in cell numbers and detect apoptotic nuclei respectively. Expression of Bax and Caspase-3 genes was significantly (p < 0.05) higher in poor quality pre-implantation embryos as compared with that of morphologically good quality embryos of the same developmental stages. Moreover, Mcl-1 expression was significantly higher in good quality immature oocytes than that in the poor quality group. Moreover, higher DNA fragmentation was evidenced in morphologically poor quality blastocysts. In conclusion, our study demonstrates that Bax, caspase-3 and Mcl-1 can be used as potential markers of embryo quality to evaluate in vitro-produced bovine embryos. Further studies are required to investigate specific molecular signatures that can be used in evaluating in vivo-derived embryos.

Expression of survivin and p53 proteins and their correlation with hormone receptor status in Indian breast cancer patients

In invasive ductal carcinoma (IDC), many antiapoptotic and proapoptotic genes regulate disease outcome. Hormone receptor-mediated mechanisms have also been shown to prevent apoptosis. Therefore, relations between hormone receptor status and other molecular markers need further examination. In the present study, we analyzed the expression of apoptosis-regulating genes, viz., Survivin and mutant p53, in benign breast disease (fibroadenoma) and IDC patients. Results were then correlated with hormone receptor status of the patients. Paraffin-embedded tissue samples from 63 untreated female patients with IDC and 32 female patients with fibroadenoma were used. Expression of Survivin and mutant p53 was evaluated using immunohistochemical staining method. Fisher exact test and nonparametric correlation test (Spearman rank correlation test) were performed. Results : In fibroadenoma, 53% of patients expressed Survivin and 13% of patients expressed p53 protein. Statistically significant increase in Survivin and p53 protein expression was observed in carcinoma cases. Survivin expression correlated negatively with progesterone receptor (PR) status, but its expression was independent of estrogen receptor (ER) status. p53 expression showed negative correlation with both ER and PR status. Increased expression of Survivin and p53 in IDC patients and correlation with hormone receptors suggest that Survivin and p53 along with hormone receptors status are likely to contribute significantly to apoptosis resistance and may serve as therapeutic target that could increase the effectiveness of conventional breast cancer therapy.

The Role of Strain Variation in BAX and BCL-2 Expression in Murine Bleomycin-Induced Pulmonary Fibrosis

This study hypothesized that the expression of apoptosis-regulatory genes, such as BCL-2 and BAX may be affected by genetic variation in bleomycin-induced pulmonary fibrosis in C57BL/6 and NMRI mice. Pulmonary fibrosis induced by single intratracheal dose of bleomycin (3 U kg(-1)). After 2 weeks, lung samples were analyzed for collagen deposition, pathological changes and expression of BCL-2 and BAX. The fibrotic lung changes were similar in both strains. The immunohistochemical assay using a biotin-streptavidin technique showed no significant difference in immunoreactivity for BCL-2 protein between the controls and bleomycin-treated C57BL/6 mice. However, in NMRI mice, the expression of BCL-2 was significantly (p<0.05) upregulated in myofibroblasts and neutrophils. The expression of BAX protein was significantly (p<0.05) upregulated in alveolar epithelial cells of both strains and downregulated in myofibroblasts and lymphocytes of the lung tissues of C57BL/6 mice and also in lymphocytes of NMRI mice at 2 weeks after bleomycin instillation. These results confirm the role of BCL-2 and BAX proteins in the pathogenesis of pulmonary fibrosis and suggest that the expression of apoptotic regulatory genes may be specific in different cell types in various strains.

Role of PARP-1 and PARP-2 in the expression of apoptosis-regulating genes in HeLa cells

Poly (ADP-ribose) polymerase-1 (PARP-1) is a DNA-binding enzyme involved in DNA damage processing, apoptosis, and genetic stability. Many lines of evidence suggest that PARP-1 is implicated in transcriptional regulation of various genes through the modulation of chromatin structure or through direct interaction with transcription factors and/or transcription factor-binding sites. In the present study, we applied TaqMan Low-Density Array analyses to investigate the expression of genes involved in apoptotic cell death induced by an alkylating agent. Using RNA interference, we determined the roles of PARP-1 and PARP-2 in transcriptional regulation during apoptosis in HeLa cells. Of the 93 genes monitored, 33 differentially expressed genes were identified after induction of apoptosis. Whereas the down-regulation of PARP-1 and PARP-2 had no impact on gene expression per se, we observed that Bcl10, c-Rel, and tumor necrosis factor-related apoptosis-inducing ligand receptor-1 and -2 are differentially expressed after induction of apoptosis in a PARP-1-dependent manner. These findings suggest that PARP-1-but not PARP-2-is required for proper expression of major genes involved in regulation of apoptosis.

Follistatin antagonizes transforming growth factor-β3-induced epithelial–mesenchymal transition in vitro: implications for murine palatal development supported by microarray analysis

Epithelial–mesenchymal transition (EMT) is involved in normal embryonic development as well as in tumor progression and invasiveness. This process is also known to be a crucial step in palatogenesis during fusion of the bi-lateral palatal processes. Disruption of this step results in a cleft palate, which is among the most frequent birth defects in humans. A number of genes and encoded proteins have been shown to play a role in this developmental stage. The central role is attributed to the cytokine transforming growth factor-β3 (TGF-β3), which is expressed in the medial edge epithelium (MEE) already before the fusion process. The MEE covers the tips of the growing palatal shelves and eventually undergoes EMT or programmed cell death (apoptosis). TGF-β3 is described to induce EMT in embryonic palates. With regard to the early expression of this molecule before the fusion process, it is not well understood which mechanisms prevent the TGF-β3 producing epithelial cells from undergoing differentiation precociously. We used the murine palatal fusion to study the regulation of EMT. Specifically, we analyzed the MEE for the expression of known antagonists of TGF-β molecules using in situ hybridization and detected the gene coding for Follistatin to be co-expressed with TGF-β3. Further, we could show that Follistatin directly binds to TGF-β3 and that it completely blocks TGF-β3-induced EMT of the normal murine mammary gland (NMuMG) epithelial cell line in vitro. In addition, we analyzed the gene expression profile of NMuMG cells during TGF-β3-induced EMT by microarray hybridization, detecting strong changes in the expression of apoptosis-regulating genes.

Oligonucleotide Microarray Analysis of Genes Regulating Apoptosis in Chronically Ischemic and Postinfarction Myocardium

The pathology of cardiomyocyte death during and after myocardial infarction involves both necrosis and apoptosis. Although both mechanisms lead to cell death, participation of apoptosis in this process carries the potential of developing therapies influencing at least part of the population of dying cells. Therefore the aim of this study was to determine (using oligonucleotide microarrays) expression profiles of apoptosis-regulating genes in postinfarction myocardium, comparing chronically ischemic and healthy heart muscle. Tissue samples were obtained during elective surgery from the right cardiac auricles of three patients. The expression of 141 genes involved in fibrosis was assessed using the Affymetrix HG_U133A microarray. The patients' transcriptomes were compared using hierarchical clusterization. Differentiating genes were determined using regression analysis and Bland-Altman graph analysis. Hierarchical clusterization demonstrated that the profile of gene expression in postinfarction myocardium was different from that in the remaining specimens. Further statistical analysis showed two important differentiating genes: FOXO3A (underexpressed in post-MI sample) and CFLAR (overexpressed in post-MI sample). The expression of apoptosis-regulating genes is significantly different in post-MI myocardium from chronically ischemic and a nonischemic myocardium. Our results suggest that CFLAR is important in the induction of apoptosis in postinfarction cardiac tissue.

In Vivo Tumor Dynamic Studies in Stable CLL Show an Association between CLL Turnover Rates and IgVH Mutational Status and Provide Evidence That the Bone Marrow Is Not a Major Site of Neoplastic Cell Generation.

The classic view of CLL as a static disease has recently been challenged by the first in vivo CLL cell kinetics study (Messmer BT, et al. J Clin Invest. 2005). In a clinical heterogeneous CLL patient cohort not only substantial proliferation rates but also increased death rates were observed, supporting the concept of CLL as a dynamic disease. Whether this dynamic state also applies to patients with untreated clinically stable disease (and lymphocyte numbers) is currently not known. Proliferation of tumor cells is assumed to take place in proliferation centers in lymph nodes (LN) and bone marrow (BM), where survival largely depends on micro-environmental stimuli within these tissues. CLL cell death is thought to occur preferentially in the peripheral blood (PB). Although involvement of lymph nodes in both proliferation and cell survival has been studied well the precise role of the bone marrow is much less clear. The aim of the present study was to measure and model in vivo CLL kinetics using deuterated water labeling in clinically stable untreated CLL patients in relation to IgVH mutation status and expression of apoptosis-regulatory genes in PB and BM. Ten untreated CLL patients with stable disease activity and IgVH mutation status levels between 0.3% and 11.2% (median 3.5%) daily drank deuterated water (2H2O) for 64 days. To monitor PB CLL kinetics, blood and urine were collected at regular intervals during the up- and downlabeling phase. At day 64 and 413 (end of downlabeling period) a bone marrow puncture was performed. Out of the different samples (BM: first syringe of aspirate) CD19+CD5+ cells were sorted and incorporation of 2H in the DNA of the leukemic cell population was measured by gas chromatography and mass-spectrometry. Average proliferation and disappearance rates of the labeled population were estimated with a mathematical model (simultaneously) describing the up- and downlabeling phase. Expression of mRNA levels of pro- and anti-apoptotic molecules was determined by Multiple Ligation-dependent Probe Amplification (MLPA). Although proliferation rates varied markedly within this clinically homogenous patient cohort (proliferation rates per day: 0.08% – 0.32%, median 0.15%), they were balanced in all patients by similar disappearance rates. Strikingly, the degree of IgVH mutation was inversely associated with both proliferation and disappearance rates of the leukemic B cells. At day 64, the percentage of labeled cells was higher in the BM as compared to PB (15.9% vs. 11.1% of total CLL cells, p<0.05), although expression of both proliferation markers Ki67 and survivin (as assessed by flow-cytometry and MLPA) of the leukemic cells in both compartments was similar. In contrast to LN-derived CLL cells (Smit LA, et al. Blood. 2007) apoptotic regulatory gene expression of CLL cells in BM revealed no increased expression of anti-apoptotic molecules as compared to PB. Our data indicate that the dynamic state of clinically stable CLL is associated with the degree of IgVH mutations. Furthermore, the bone marrow seems to be a tumor reservoir rather than a CLL proliferation compartment.

Apoptotic effect of hesperidin through caspase3 activation in human colon cancer cells, SNU-C4

Hesperidin, a known flavonoid constituent of citrus, reduces the proliferation of many cancer cells. The apoptotic effects of hesperidin on human colon cancer cells, SNU-C4, were determined at concentrations of 1-100 microM. At 100 microM, hesperidin reduced cell viability to 65.00+/-0.05% of control values in a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell death induced by hesperidin showed apoptotic features in 4,6-diamidino-2-phenylindole (DAPI) staining and in terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assays. Examination of the expression of apoptosis-regulating genes indicated that hesperidin treatment decreased the expression of B-cell CLL/lymphoma 2 (BCL2) mRNA, and increased the expression of BCL2-associated X protein (BAX). The expression and activity of the major apoptotic factor caspase3 (CASP3) was increased significantly with hesperidin treatment. Hesperidin down-regulated the protein expression of pro-CASP3, and up-regulated the level of active CASP3. Thus, these results suggest that hesperidin could induce apoptosis in human colon cancer cells through CASP3 activation.

Effect of Mycoplasmas on Apoptosis of 32D Cells Is Species-Dependent

We previously showed that mycoplasmal infection effectively prevented apoptosis of infected cells, whereas other researchers have indicated that mycoplasmal infection promoted apoptosis. To understand the mechanism underlying this discrepancy, five different species of mycoplasmas were investigated for their effects on apoptosis of interleukin (IL)-3-dependent 32D cells. Results revealed that Mycoplasma fermentans and M. penetrans effectively supported continuous growth of 32D cells after IL-3 withdrawal. M. fermentans was more potent than M. penetrans. This effect was achieved by way of preventing apoptosis and stimulating cell proliferation. On the contrary, M. hominis and M. salivarium accelerated apoptosis of 32D cells. M. genitalium had no significant effect on apoptosis. The RNase protection assay indicated that the proapoptotic and antiapoptotic mycoplasmas altered the expression of major apoptosis regulatory genes differently. The difference in apoptosis regulatory gene expression induced by different species of mycoplasmas might be accountable for their effects on host cell apoptosis.

Quantitative expression of apoptosis-regulating genes in endometrium from women with and without endometriosis

To quantitate antiapoptotic and proapoptotic gene expression in endometrial cells (ECs) of women with and without endometriosis. Determination of transcript abundance (TA) of apoptosis-regulating genes in eutopic and ectopic endometrial cells. Institute for the Study and Treatment of Endometriosis, Chicago, Illinois, and university-based research laboratories. Women with (n = 10) and without (n = 6) endometriosis. None. Quantitative virtually multiplexed transcript abundance measurement (VMTA) of the BCL2, BCLxL, defender against cell death-1 (DAD-1), BCLxS, P53, Caspase-1, and proliferating cell nuclear antigen (PCNA) genes. The TA ratio of antiapoptotic to proapoptotic isoforms of the BCL-X gene favors survival in eutopic and ectopic ECs from women with endometriosis, but not control ECs. This was found throughout the menstrual cycle for ectopic ECs. Eutopic but not ectopic ECs also expressed increased TA of the antiapoptotic DAD-1 gene in endometriosis. Eutopic and ectopic ECs from women with endometriosis expressed decreased TA of p53 and Caspase-1 compared to ECs from women without endometriosis. Expression of these genes was not correlated with the proliferative state of ECs based on TA of the PCNA gene. Dysregulation in expression of pro- and antiapoptotic regulatory genes characterizes eutopic and ectopic ECs from women with endometriosis. These results are consistent with apoptotic resistance and enhanced survival of ECs in endometriosis.

Effects of maternal undernutrition during early pregnancy on apoptosis regulators in the ovine fetal ovary

This study aimed to determine whether reduced fetal ovary folliculogenesis in ewes undernourished during early/midpregnancy is associated with altered ovarian cell proliferation and/or the expression of apoptosis-regulating genes. Groups of ewes (n = 11-19) were fed either 100% (high; H) or 50% (low; L) of metabolisable energy requirements for live-weight maintenance during selected windows of gestation. All animals were killed at days 50, 65 or 110 of gestation. Between mating and slaughter, control animals were fed the H ration, while animals of other subgroups were fed the L ration from (a) mating to slaughter at 50, 65 or 110 days; (b) 0 to 30 days; (c) 31 to 50 or 65 days; or (d), in the day 110 slaughter group only, from 66 to 110 days. Bouin's-fixed fetal ovaries were examined for (a) Ki67 immunoexpression (proliferation) and (b) Bax and Mcl-1 (apoptosis-regulating genes) expression by in situ hybridisation (day 110) and immunohistochemistry (days 50, 65 and 110). At day 50, maternal nutrition had no effect on Ki67, predominant in germ cells, or Bax and Mcl-1, predominant in the oocytes. Restricted maternal food intake from 0 to 30 days significantly reduced staining for Ki67 in germ cells at day 65 (P < 0.05) but increased staining in granulosa cells at day 110 (P < 0.05). In animals fed the L ration for 110 days, primordial follicle Bax and Mcl-1 were significantly increased (Bax: P < 0.01; Mcl-1: P < 0.05). Granulosa cell Bax was also increased (P < 0.05). When the L ration was fed from 66 to 110 days, granulosa cell Bax (P < 0.05) and primordial follicle Mcl-1 (P < 0.01) were also significantly increased. In the fetal ovarian vasculature, animals underfed for 0-110 days had significantly elevated perivascular Mcl-1 (P < 0.001) and endothelial Bax expression (P < 0.05). Moreover, at day 110, endothelial Mcl-1 was increased by underfeeding from 0 to 30 days (P < 0.05). These data indicate that maternal undernutrition alters proliferation and the expression of apoptosis-regulating genes in the developing fetal ovary. The precise mechanism depends on the window of maternal food restriction.

Animal models for the study of squamous cell carcinoma of the upper aerodigestive tract: A historical perspective with review of their utility and limitations part B. Transgenic mouse models

Animal models for the study of squamous cell carcinoma of the upper aerodigestive tract: A historical perspective with review of their utility and limitations part B. Transgenic mouse models

Effects of human cytomegalovirus infection on apoptosis and expression of apoptosis-regulating factors

The present study aimed to find out dynamic changes of apoptosis in human cytomegalovirus (HCMV) infected cells and the influence of HCMV infection on activation of caspase-3 and the expression of apoptosis-regulating genes, bcl-2 and fas mRNA. The sequential changes of apoptotic cell rate in high and low MOI (MOI = 2.5 and 0.25 respectively) of HCMV infected human embryonic lung fibroblasts (HELFs) at 1 h, 12 h, 24 h, 36 h, 48 h, 72 h and 96 h post-infection were measured by flow cytometry. The expression levels of caspase-3 protein and bcl-2 and fas mRNA in HCMV infected cells (MOI = 0.25) at 72 h post-infection were detected by Western blot and in situ hybridization methods, respectively. It was found that the ratio of apoptotic cells in normal controls was consistently lower, but the rates in low and high MOI infected cells were gradually increased with time prolonged, reached peak at 96 h (8.85%) and 72 h (25.63%), respectively. By Western blot analysis, only a narrow band of 32 kD (1 kD = 0.992 1 ku) procaspase-3 was found in normal cells, but a wider procaspase-3 band and a much wider band of 17 kD proteins (p17) appeared in the infected cells. Meanwhile, the expression of bcl-2 mRNA was higher and that of fas mRNA was lower in the normal HELF cells, whereas there were significantly lower bcl-2 mRNA and higher fas mRNA expression levels in HCMV infected cells. It was concluded that HCMV was a stronger inducer of apoptosis in HELF cells. Caspase-3, as the marker of undergoing apoptosis, was expressed increasingly and activated in the infected cells, indicating its action in HCMV-inducing apoptosis. Down-regulating bcl-2 mRNA expression and up-regulating fas mRNA expression were also involved in the mechanism of HCMV-induced apoptosis.

Expression of C‐IAP1, C‐IAP2 and SURVIVIN discriminates different types of lymphoid malignancies

(De-)regulation of apoptosis plays an important role in normal and malignant lymphopoiesis. Apoptosis-regulating genes of the BCL-2 family and the recently identified inhibitors of apoptosis (IAP) family have been implicated in different types of non-Hodgkin lymphoma (NHL). To investigate whether expression of specific apoptosis-regulating genes correlated with different types of lymphoid malignancies, we measured the expression of five BCL-2 family genes, four IAP family genes and SMAC by real-time quantitative polymerase chain reaction in patient samples. In total, 137 samples from B- and T-cell acute lymphoblastic leukaemia (ALL), B-cell chronic lymphocytic leukaemia (CLL), six different NHL types and three control tissue types were analysed. The data were further analysed using cluster and discriminant analysis. Three specific expression patterns were identified for CLL, ALL and NHL respectively. CLL samples, as well as B-ALL and follicular lymphoma samples showed high similarity in the expression of these apoptosis-regulating genes and could be distinguished from each other and other diseases and controls. Discriminant analysis identified three members of the IAP family, C-IAP1, C-IAP2 and SURVIVIN, as the most informative genes to discriminate between these lymphoid malignancies.

Microarray analysis identifies apoptosis regulatory gene expression in HCT116 cells infected with thermostable direct hemolysin-deletion mutant of Vibrio parahaemolyticus

The thermostable direct hemolysin (TDH) is considered as a major virulence factor of Vibrio parahaemolyticus. We observed this potential in several human cancer cell lines by using the TDH-producing wild-type (RIMD2210633) as well as tdh-deletion mutant of V. parahaemolyticus and found that the deletion of tdh did not affect cytotoxicity to any of the cell lines tested. DNA fragmentation and annexin V staining showed that both wild-type and tdh-mutant trigger apoptosis in these cells. To understand the molecular basis of cell death in the absence of TDH, gene expression profile of human colon cancer cell line HCT116 infected with tdh-deletion mutant was carried out using human cDNA microarrays consisting of 33,000 known genes. In infected cells, differentially expressed genes including genes for early growth response, growth arrest and DNA damage, and activating transcription factor that affect programmed cell death pathways were detected. Interestingly, mutant strains having a deletion in type III secretion system 1 (TTSS1) failed to elicit DNA fragmentation in HCT116 cells. Our results strongly suggest that apoptosis requires functional TTSS1 and TTSS1-dependent translocation factor(s) to be associated with the host cell death, and thus pathogenesis of V. parahaemolyticus.

Loss of BNIP3 expression is a late event in pancreatic cancer contributing to chemoresistance and worsened prognosis

Altered expression of apoptosis-regulating genes plays an important role in the aggressive growth behavior and chemoresistance of pancreatic ductal adenocarcinoma. In the present study, the hypoxia-inducible proapoptotic gene, BNIP3, was analysed in terms of expression, effect on patient survival, and chemo-responsiveness in pancreatic cancer cell lines. cDNA microarray, real-time light cycler quantitative polymerase chain reaction, laser-capture microdissection, and immunohistochemistry analyses were used to evaluate BNIP3 expression in normal and diseased pancreatic specimens. Modulation of BNIP3 expression was achieved using specific siRNA molecules. The effect of chemotherapeutic agents on pancreatic cancer cells was assessed utilizing 3-(4,5-methylthiazol-2-yl)-2,5-diphenyl-tetrazolium-bromide assays. BNIP3 mRNA levels were 3.0- and 6.3-fold lower in chronic pancreatitis and pancreatic cancer compared to the normal pancreas, respectively. Microdissection analysis confirmed the reduction of BNIP3 expression in pancreatic cancer cells compared to normal duct cells. By immunohistochemistry, BNIP3 was predominantly expressed in the acinar cells of the normal and diseased pancreas. Interestingly, while BNIP3 was undetectable in the cancer cells of 59% of the cases, 75-100% of PanIN2/3 lesions displayed BNIP3 immunoreactivity. Loss of BNIP3 expression correlated with poorer survival of patients (8 vs 14 months for BNIP3 negative vs positive tumors). Hypoxia induced BNIP3 expression in four out of eight pancreatic cancer cell lines, while it was absent under normoxic and hypoxic conditions in the remaining four. Downregulation of BNIP3 resulted in increased resistance to 5-fluoro-uracil and gemcitabine. In conclusion, loss of BNIP3 expression occurs late in pancreatic cancer, contributes to resistance to chemotherapy, and correlates with a worsened prognosis.