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Objectives Materials and Methods Results Conclusions This study aimed to screen oral squamous cell carcinoma (OSCC) diagnostic and prognostic candidates and investigate the potential functions and mechanisms of candidates in the chemoresistance of OSCC cell lines.Differential expression profiling of lncRNA was performed in a large cohort of OSCC patients from the Cancer Genome Atlas database to identify OSCC diagnostic and prognostic candidates. Taxol resistance in OSCC cell lines was analyzed using MTT assay. OSCC cell lines transfected with EIF3J‐DT pcDNA or siRNA were used to determine its regulatory effects on apoptosis, cell cycle distribution and autophagy using flow cytometry and western blot.We identified EIF3J‐DT as a candidate for OSCC diagnosis and prognosis. The expression level of EIF3J‐DT in OSCC cell lines correlates with taxol resistance. EIF3J‐DT silencing attenuated taxol resistance, and EIF3J‐DT overexpression enhanced taxol resistance in OSCC cell lines. Silencing of EIF3J‐DT reduced taxol resistance by inducing apoptosis, cell cycle arrest, and ATG14‐mediated autophagy inhibition in OSCC cell lines.We found that EIF3J‐DT induced chemoresistance by regulating apoptosis, cell cycle, and autophagy in OSCC cell lines, which EIF3J‐DT might provide a novel therapeutic approach for OSCC as well as a diagnostic and prognostic factor. [ABSTRACT FROM AUTHOR]

Ampelopsin (AMP) is a well-known flavonoid that exerts a number of biological and pharmacological effects including anticancer effects against several cancer cell lines. In this study, we investigated the anticancer activity of AMP against Epstein-Barr virus (EBV)-positive cells and its mechanism of action. Our results showed that AMP dose-dependently inhibited cell viability and induced apoptotic cell death in EBV-positive cells without cytotoxicity in EBV-negative cells. In particular, AMP induced caspase-8 dependent apoptosis via upregulation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and death receptor (DR5). Knockdown of DR5 by RNA interference blocked AMP-induced apoptosis. Furthermore, AMP dose-dependently activated p38 mitogen-activated protein kinases (MAPKs) in EBV-positive cells. Additionally, SB203580 (a p38-MAPK inhibitor) effectively inhibited apoptotic cell death. These results demonstrate that treatment with AMP induces the apoptosis of EBV-positive cells through upregulation of TRAIL/DR5 and activation of p38 signaling. Therefore, these results provide experimental information for developing AMP as a new therapeutic drug against EBV-positive cancer. [ABSTRACT FROM AUTHOR]

Transforming growth factor-β (TGF-β) signaling transduction initiates TGF-β activation, resulting in activation of TGF-β receptor II (TGFBR2). Any quantitative and qualitative changes in TGFBR2 are expected to affect the TGF-β signaling pathway, which occupies a central position with respect to the regulation of cell growth, differentiation, apoptosis, immune reaction, angiogenesis and extracellular matrix formation. Recent studies have shown that TGF-β1 gene polymorphisms may confer susceptibility to early acute and chronic allograft rejection in kidney transplantation recipients. In this study, we assessed whether polymorphisms of the TGFBR2 gene were associated with susceptibility to kidney transplantation rejection. A total of 347 renal allograft recipients transplanted at three centers in Korea were analyzed. Three SNPs (rs764522, rs3087465, rs2228048) of the TGFBR2 gene were genotyped from genomic DNA with direct sequencing. Multiple logistic regression models (codominant, dominant, recessive, and log-additive) were performed to evaluate odds ratios (ORs), 95% confidence intervals (CIs), and p-values. A total of 63 patients (18%) developed acute rejection (AR). There were no significant differences in age, sex, number of HLA mismatches, cause of renal failure, or immunosuppressant regimen between the AR and non-AR group. The synonymous SNP rs2228048 was significantly associated with AR (p = 0.020 in recessive model, and p = 0.036 in log-additive model. The allele frequencies of rs2228048 were different between the AR and non-AR group (p = 0.026). These results suggest that the synonymous TGFBR2 gene SNP rs2228048 may be associated with the development of AR in Korean kidney transplantation recipients. [ABSTRACT FROM AUTHOR]

Abstract: Salubrinal is a specific eIF2α phosphatase inhibitor that inhibits ER stress-mediated apoptosis. However, maintaining hyper-phosphorylated eIF2α state with high doses of salubrinal treatment promotes apoptosis in some cancer cells. In this report, we found that salubrinal induced apoptosis of EBV-transformed B cells. Notably, salubrinal induced ROS generation and p38 MPAK activation, which then induced expression of FasL. Moreover, salubrinal subsequently led to activation of caspases, calcium redistribution, Bax translocation, cytochrome c release, and apoptosis. These findings suggest that salubrinal may be a novel therapeutic approach for EBV-associated malignant diseases. [Copyright &y& Elsevier]

Abstract: After primary infection of B cells with Epstein-Barr virus (EBV), infected B cells express several viral homologs of human genes that promote activation (LMP1 and CD40) or survival (BHRF and BCL2). EBV-infected B cells also express germinal center phenotype markers, such as CD77, PNA, CD95, and CD38. This transformation of B cells by EBV infection resembles normal B-cell activation and differentiation arising in the germinal center. In the present study, we found that EBV-transformed B cells expressed centrocyte/centroblast marker 1 (CM1), a possible marker of GC B cells and an inducer of their apoptosis. Moreover, ligation of CM1 on EBV-transformed B cells by immobilized anti-CM1 monoclonal antibody induced cell death. The ligation of CM1 immediately increased the generation of intracellular reactive oxygen species (ROS) and disrupted the mitochondrial membrane potential. Pretreatment with N-acetyl cystein (an ROS inhibitor) almost completely blocked this cell death, but Z-VAD-fmk (a caspase inhibitor) did not. We further investigated whether apoptosis-inducing factor (AIF) and endonuclease G (EndoG), which are both related to caspase-independent cell death, would be translocated to the nucleus during the ligation of CM1. We found that AIF and EndoG were released to the cytosplam but not translocated to the nucleus. Moreover, cytochalasin D, a cytoskeleton disruptor, rescued the cells from CM1-mediated cell death and blocked ROS generation. Therefore, it is conceivable that CM1 signaling might provoke cytoskeleton polymerization and trigger ROS generation. Taking these observations together, we conclude that the ligation of CM1 on EBV-transformed B cells can cause cell death via the ROS produced by F-actin polymerization in a caspase-independent manner, although this cell death might be unrelated to AIF and EndoG release from the mitochondria. [Copyright &y& Elsevier]

Alzheimer's disease (AD) is the most common form of dementia with irreversible neurodegeneration. Accumulation of amyloid beta (Aβ) in the brain is considered to be a major cause of neuronal cell death in AD, but the neurotoxic mechanism of Aβ is not yet fully understood. Here, we focused on the role of microRNAs (miRNAs) in Aβ-induced neuronal cell death. In microarray and RT-qPCR analysis of plasma miRNAs obtained from 5 familiar AD mutations (5xFAD) and wild-type (WT) mice of various ages, miR-16-5p showed a significant age-related change that was accompanied by neuronal cell death in the brain tissue of 5xFAD mice. In addition, increased miR-16-5p was prominent near Aβ plaque-deposition sites in 5xFAD mouse brains. Aβ treatment induced miR-16-5p upregulation and apoptosis in primary cultured mouse cortical neurons and the SH-SY5Y human neuroblastoma cell line. In silico analysis and reporter gene assays indicated that miR-16-5p directly targets the mRNA encoding the anti-apoptotic factor, B cell lymphoma-2 (BCL-2), in the neuronal cell line. Overexpression of miR-16-5p in SH-SY5Y cells downregulated BCL-2 expression and induced apoptosis. These results collectively suggest that the miR-16-5p/BCL-2 axis plays an important role for neuronal cell apoptosis in AD. • Loss of neuron occurred near Aβ plaques in the 5xFAD mouse brains. • miR-16-5p was upregulated by Aβ deposition in in vivo and in vitro AD models. • Upregulation of miR-16-5p caused neuronal cell apoptosis via targeting BCL-2. • Upregulation of miR-16-5p may be a risk factor for neuronal cell apoptosis in AD. [ABSTRACT FROM AUTHOR]

Abstract: Recent studies have shown that indoleamine 2,3-dioxygenase (IDO) plays a pivotal role in the modulation of immune response against tumor and virus infection. Here we demonstrate the pro-apoptotic effect of l-kynurenine, a tryptophan catabolite of IDO, on human NK cell line, NK92 MI. Treatment with l-kynurenine dose-dependently induced growth inhibition and apoptosis in NK92 MI cells. Treatment with the antioxidant NAC completely protected cells from l-kynurenine-induced apoptosis. Moreover, we found that treatment with Z-VAD-fmk and ZB4 slightly inhibited l-kynurenine-induced apoptosis, suggesting that l-kynurenine-induced apoptosis in NK cells occurs primarily through an ROS mediated pathway. We observed that the presence of NAC blocks cytochrome c release and activation of caspase-3 during l-kynurenine-induced apoptosis. Overall, we conclude that l-kynurenine resulting from IDO can cause cell death via ROS pathway in NK cells. Our findings provide a new insight into the interaction between NK cells and IDO positive cancer cells in regulating immune responses. [Copyright &y& Elsevier]

Abstract: B7-H4 has an inhibitory effect on immune responses via the down-regulation of T cell-mediated immunity, but how the engagement of B7-H4 molecules by counter molecules affects the signaling mechanism of the B7-H4-expressing cells is poorly defined. In this study, we found that B7-H4 expression was enhanced on B cells infected with Epstein–Barr virus (EBV) and that triggering of these molecules induced apoptosis of EBV-transformed B cells. Engagement of B7-H4 initially increased intracellular level of ROS, which then induced the expression of FasL. Engagement of B7-H4 subsequently provoked Fas-mediated and caspase-dependent apoptosis in association with cytochrome c and AIF, and EndoG was released from the mitochondria on EBV-transformed B cells. These results suggest that B7-H4 may be a potential therapeutic target for EBV involved malignancy diseases. [Copyright &y& Elsevier]

Burkitt lymphoma (BL) is a tumor with the characteristics of germinal center B cells. We previously reported that the CM1 (centrocyte/−blast marker 1) molecule is expressed only in germinal center B cells, specifically, in a subpopulation of centroblasts and centrocytes. In the present study, we investigated the apoptosis induced by anti-CM1 in the Ramos and Raji human BL cell lines. The Ramos is protected from apoptosis by the crosslinking of sIgM and the calcium ionophore by the ligation of CD40 with anti-CD40 monoclonal antibodies (mAb) or soluble CD40 ligand (sCD40L). In this investigation on the effect of CM1 on apoptosis in BL cell lines, we found that cellular signaling by CM1 induces apoptosis and decreases cell viability, in BL cell lines cultured for 24 hours with protein-G agarose beads conjugated anti-CM1 mAb. Stimulation by CD40 ligated with sCD40L protected Raji cells from CM1-induced apoptosis, but did not protect Ramos cells. Furthermore, after anti-CM1 mAb stimulation, CD95 expression was upregulated and CD40 expression was unaltered or slightly decreased in Ramos cells, whereas CD95 was downregulated and CD40 was slightly upregulated in Raji cells. The engagement of CD40 by sCD40L enhanced CD95 expression, but the level of CM1 expression was unchanged in Ramos. However, sCD40L downregulated both CD95 and CM1 expression in Raji. In addition, the caspase-8 specific inhibitor blocked CM1-induced apoptosis in Ramos cells, but not in Raji cells. Increased mitochondrial membrane permeabilization was observed only in Raji cells. Moreover, the effector caspase inhibitor, z-DEVD, blocked CM1-mediated apoptosis in both cell lines. We found that CM1-induced apoptosis is achieved via different initiation pathways, which are cell-type dependent. [Copyright &y& Elsevier]

Annona muricata L., known as graviola, is an evergreen plant of the tropical regions and is a rich source of natural products. Graviola has various biological activities, and it is best known for its anticancer activity. This study aimed to investigate the effects of crude graviola extract in vitro on breast cancer cells; in particular, we aimed to identify an agent against triple negative breast cancer (TNBC). We used the TNBC MDA-MB-231 cell line as the experimental model and the ER(+) non-TNBC MCF-7 breast cancer cell line as the control. We identified annonaceous acetogenins, including annonacin isomers, characteristic to this plant by using liquid chromatography tandem mass spectrometry (LC/MS/MS). We observed a significant decrease in the cell viability in both cell lines within 48 h, whereas impaired cell motility and invasiveness were observed only in the MDA-MB-231 cell line. While the MCF-7 cells showed an ER-dependent mechanism of apoptosis, the apoptosis of MDA-MB-231 cells was governed by an intrinsic apoptotic pathway triggered by graviola leaf extract (GLE). [ABSTRACT FROM AUTHOR]

Ginsenoside Rg3 (Rg3), a pharmacologically active compound from red ginseng, has been reported to induce cell death in various cancer cell lines, although the specific mechanisms have not been well established. In the present study, Rg3 treatment to A549 human lung adenocarcinoma led to cell death via not only apoptotic pathways but also the downregulation of epidermal growth factor receptor (EGFR). We used cross-linker and cell enzyme-linked immunosorbent assays to show that Rg3 inhibited EGFR dimerization by EGF stimulation and caused EGFR internalization from the cell membrane. Among several important phosphorylation sites in cytoplasmic EGFR, Rg3 increased the phosphorylation of tyrosine 1045 (pY1045) and serine 1046/1047 (pS1046/1047) for EGFR degradation and coincidently, attenuated pY1173 and pY1068 for mitogen-activated protein kinase activity. These effects were amplified under EGF-pretreated Rg3 stimulation. In vivo experiments showed that the average volume of the tumors treated with 30 mg/kg of Rg3 was significantly decreased by 40% compared with the control. Through immunohistochemistry, we detected the fragmentation of DNA, the accumulation of Rg3, and the reduction of EGFR expression in the Rg3-treated groups. Here, we provide the first description of the roles of Rg3 in the reduction of cell surface EGFR, the attenuation of EGFR signal transduction, and the eventual activation of apoptosis in A549 human lung adenocarcinoma. [ABSTRACT FROM AUTHOR]

We demonstrate that chikusetsusaponin IVa methyl ester (CME), a triterpenoid saponin from the root of Achyranthes japonica , has an anticancer activity. We investigate its molecular mechanism in depth in HCT116 cells. CME reduces the amount of β-catenin in nucleus and inhibits the binding of β-catenin to specific DNA sequences (TCF binding elements, TBE) in target gene promoters. Thus, CME appears to decrease the expression of cell cycle regulatory proteins such as Cyclin D1, as a representative target for β-catenin, as well as CDK2 and CDK4. As a result of the decrease of the cell cycle regulatory proteins, CME inhibits cell proliferation by arresting the cell cycle at the G0/G1 phase. Therefore, we suggest that CME as a novel Wnt/β-catenin inhibitor can be a putative agent for the treatment of colorectal cancers. [ABSTRACT FROM AUTHOR]

Rotenone, an inhibitor of mitochondrial complex I, has been widely regarded as a neurotoxin because it induces a Parkinson's disease-like syndrome. The fruit and root bark of Lycium chinense Miller have been used as traditional medicines in Asia to treat neurodegenerative diseases. In this study, we examined the neuroprotective effects of Lycium chinense Miller extracts in rotenone-treated PC12 cells. Treatment with rotenone reduced PC12 cell viability and cellular ATP levels. Conversely, caspase 3/7 activity, the ratio of Bax:Bcl-2 expression levels, mitochondrial superoxide level, and intracellular calcium (Ca2+) concentration were elevated. Pretreatment with Lycium chinense Miller extracts significantly increased cell viability and ATP levels. Additionally, they attenuated caspase activation, mitochondrial membrane depolarization and mitochondrial superoxide production. Moreover, confocal microscopy showed that the mitochondrial staining pattern was restored from that of extracts treated cells and that the increase in intracellular 2+ level was blunted by treatment with the extracts. Our results suggest that Lycium chinense Miller extracts may have the possible beneficial effects in Parkinson's disease by attenuating rotenone induced toxicity. [ABSTRACT FROM AUTHOR]

Highlights: [•] Akebia saponin PA induces autophagy and apoptosis in AGS human gastric cancer cells. [•] PI3K/Akt/mTOR and AMPK/mTOR pathways are involved in akebia saponin PA-induced autophagy. [•] Autophagy plays the main role in akebia saponin PA-induced cell death. [•] Akebia saponin PA-induced autophagy activates JNK/p38 to promote caspase-3-dependent apoptosis. [ABSTRACT FROM AUTHOR]

Rotenone is an inhibitor of mitochondrial complex I-induced neurotoxicity in PC12 cells and has been widely studied to elucidate the pathogenesis of Parkinson's disease. We investigated the neuroprotective effects of betaine on rotenone-induced neurotoxicity in PC12 cells. Betaine inhibited rotenone-induced apoptosis in a dose-dependent manner, with cell viability increasing from 50 % with rotenone treatment alone to 71 % with rotenone plus 100-μM betaine treatment. Flow cytometric analysis demonstrated cell death in the rotenone-treated cells to be over 50 %; the number of live cells increased with betaine pretreatment. Betaine pretreatment of PC12 cells attenuated rotenone-mediated mitochondrial dysfunction, including nuclear fragmentation, ATP depletion, mitochondrial membrane depolarization, caspase-3/7 activation, and reactive oxygen species production. Western blots demonstrated activation of caspase-3 and caspase-9, and their increased expression levels in rotenone-treated cells; betaine decreased caspase-3 and caspase-9 expression levels and suppressed their activation. Together, these results suggest that betaine may serve as a neuroprotective agent in the treatment of neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Abstract: Antimycin A (AMA) damages the mitochondria through inhibition of mitochondrial electron transport. In this study, exposure of L6 rat skeletal muscle cells to AMA induced a decrease in ATP content, followed by a decrease in mitochondrial membrane potential, leading to apoptosis. We evaluated the protective effects of water and ethanol extracts of Nelumbo nucifera seeds on L6 cells with AMA-induced oxidative stress. We found that the extracts reduced cellular apoptosis; preserved the mitochondrial membrane potential; protected mitochondrial ATP production; inhibited p53, Bax, and caspase 3 activities; and induced Bcl-2 production. Our results suggested that AMA induced apoptosis in L6 cells via impairment of mitochondrial function. N. nucifera extracts protected the cells from this mitochondria-mediated cell death. [Copyright &y& Elsevier]

Abstract: Ethnopharmacological relevance: Geniposidic acid (GA) is an iridoid glucoside isolated from Gardeniae jasminoides Ellis (Rubiaceae) that has long been used to treat inflammation, jaundice and hepatic disorders. Aims of the study: This study examined the cytoprotective properties of GA against d-galactosamine (GalN)/lipopolysaccharide (LPS)-induced fulminant hepatic failure. Materials and methods: Mice were given an intraperitoneal injection of GA (12.5, 25, 50mg/kg) 1h before receiving GalN (800mg/kg)/LPS (40μg/kg). Liver and blood samples were collected 1 and 8h after GalN/LPS injection. Results: The survival rate of the GA group was significantly higher than the control. GalN/LPS increased serum aminotransferase activity, serum tumor necrosis factor-α level and hepatic lipid peroxidation and decreased hepatic glutathione content. These changes were attenuated by GA. GA augmented increases in serum interleukin-6 level, heme oxygenase-1 and NF-E2-related factor 2 protein expression. Mice treated with GA decreased cleaved caspase-8 and caspase-3 protein expression and showed significantly fewer apoptotic cells. GA increased Bcl-xL protein expression and decreased Bax protein expression. Moreover, GA treatment enhanced phosphorylation of signal transducer and activator of transcription 3. Conclusion: Our findings suggest that geniposidic acid alleviates GalN/LPS-induced liver injury by enhancing antioxidative defense system and reducing apoptotic signaling pathways. [Copyright &y& Elsevier]

Abstract: Excessive stimulation of the NMDA receptor induces neuronal cell death and is implicated in the development of several neurodegenerative diseases. While EGCG suppresses apoptosis induced by NMDA receptor-mediated excitotoxicity, the mechanisms underlying this process have yet to be completely determined. This study was designed to investigate whether (−)-epigallocatechin-3-gallate (EGCG) plays a neuroprotective role by inhibiting nitric oxide (NO) production and activating cellular signaling mechanisms including MAP kinase, PI3K, and GSK-3β and acting on the antiapoptotic and the proapoptotic genes in N18D3 neural cells. The cells were pretreated with EGCG for 2 h and then exposed to quinolinic acid (QUIN), a NMDA receptor agonist, 30 mM for 24 h. MTT assay and DAPI staining were used to identify cell viability and apoptosis, respectively, and demonstrated that EGCG significantly increased cell viability and protected the cells from apoptotic death. In addition, EGCG had a capacity to reduce QUIN-induced excitotoxic cell death not only by blocking increase of intracellular calcium levels but also by inhibiting NO production. Gene expression analysis revealed that EGCG prevented the QUIN-induced expression of the proapoptotic gene, caspase-9, and increased that of the antiapoptotic genes, Bcl-XL, Bcl-2, and Bcl-w. Further examination about potential cell signaling candidate involved in this neuroprotective effect showed that immunoreacitivity of PI3K was significantly increased in the cells treated with EGCG. These results suggest that the neuroprotective mechanism of EGCG against QUIN-induced excitotoxic cell death includes regulation of PI3K and modulation of cell survival and death genes through decreasing of intracellular calcium levels and controlling of NO production. [Copyright &y& Elsevier]

Abstract: Palmatine is an isoquinoline alkaloid from Coptis chinensis, an herbal medicine used to treat various inflammatory diseases such as gastritis, edema and dermatitis. The present study examined the cytoprotective properties of palmatine on d(+)-galactosamine (GalN)/lipopolysaccharide (LPS)-induced fulminant hepatic failure. Mice were intraperitoneally given GalN (700mg/kg)/LPS (10μg/kg). Palmatine (25, 50, 100, and 200mg/kg) was administered 1h before GalN/LPS. GalN/LPS increased the mortality and serum aminotransferase activities. These increases were attenuated by palmatine. GalN/LPS increased hepatic lipid peroxidation and decreased the contents of reduced glutathione. Palmatine did not affect the lipid peroxidation and glutathione content. GalN/LPS increased the circulating levels of tumor necrosis factor (TNF)-α, interleukin-6 (IL-6) and IL-10. Palmatine prevented the increase of serum TNF-α and augmented that of serum IL-10. GalN/LPS treatment also increased the levels of TNF-α, IL-6 and IL-10 mRNA expression in liver tissue. Palmatine decreased the TNF-α mRNA expression and increased the IL-10 mRNA expression. Palmatine attenuated the apoptosis of hepatocytes, as evidenced by the TUNEL method and capase-3 analysis. Our data suggest that palmatine alleviates GalN/LPS-induced liver injury by modulating the cytokine response and inhibiting apoptosis. [Copyright &y& Elsevier]

Abstract: Phellodendri Cortex (PC) is a traditional herbal medicine, widely used in Korea and China. The effects of the methanol extract of Phellodendri Cortex (PC extract) on 1-methyl-4-phenylpyridinium (MPP+)-induced neuronal apoptosis in PC-12 cells have been investigated. MPP+-induced apoptosis in PC-12 cells was accompanied by an increased bax/bcl-2 ratio, release of cytochrome c to the cytosol and activation of caspase-3. PC extract inhibited the downregulation of bcl-2 and the upregulation of bax, as well as the release of mitochondrial cytochrome c into the cytosol. In addition, PC extract attenuated caspase-3 activation and cleavage of poly (ADP-ribose) polymerase (PARP). These results suggest that the PC extract has protective effects against MPP+-induced neuronal apoptosis in PC-12 cells. [Copyright &y& Elsevier]

Abstract: Honokiol is a naturally occurring neolignan abundant in Magnoliae Cortex and has showed anti-proliferative and pro-apoptotic effects in a wide range of human cancer cells. However, the molecular mechanisms on the anti-proliferative activity in cancer cells have been poorly elucidated. In this study, we evaluated the growth inhibitory activity of honokiol in cultured estrogen receptor (ER)-negative MDA-MB-231 human breast cancer cells. Honokiol exerted anti-proliferative activity with the cell cycle arrest at the G0/G1 phase and sequential induction of apoptotic cell death in a concentration-dependent manner. The honokiol-induced cell cycle arrest was well correlated with the suppressive expression of CDK4, cyclin D1, CDK2, cyclin E, c-Myc, and phosphorylated retinoblastoma protein (pRb) at Ser780. Apoptosis caused by honokiol was also concomitant with the cleavage of caspases (caspase-3, -8, and -9) and Bid along with the suppressive expression of Bcl-2, but it was independent on the expression of Bax and p53. In addition, honokiol-treated cells exhibited the cleavage of poly (ADP-ribose) polymerase (PARP) and DNA fragmentation. In the analysis of signal transduction pathway, honokiol down-regulated the expression and phosphorylation of c-Src, epidermal growth factor receptor (EGFR), and Akt, and consequently led to the inactivation of mTOR and its downstream signal molecules including 4E-binding protein (4E-BP) and p70 S6 kinase. These findings suggest that honokiol-mediated inhibitory activity of cancer cell growth might be related with the cell cycle arrest and induction of apoptosis via modulating signal transduction pathways. [Copyright &y& Elsevier]

Abstract: When a cell is destined for apoptosis, will its genome reprogram its transcriptional machinery to overcome the life-threatening challenge? To address this issue, we performed a genome-wide transcriptome analysis in EPO (erythropoietin) deprivation-induced apoptotic erythroid cells using the SAGE method. The results show that the transcript contents for the majority of the genes remain unchanged in the apoptotic cells, including the apoptotic genes and the heat shock genes. Of the small number of genes with an altered expression, they are mainly associated with cellular structure. Our study reveals that there is no genetic reprogramming for the transcriptional machinery in the apoptotic genome. Apoptosis, as defined by programmed cell death, is not a crisis but a peaceful physiological process. [Copyright &y& Elsevier]

Abstract: Platycodi Radix is the root of Platycodon grandiflorum and it is widely used in the traditional Oriental medicine as an expectorant for pulmonary diseases and a remedy for respiratory disorders. Platycodin D is the major constituent of triterpene saponins in the root. This study investigates apoptosis by platycodin D in immortalized human keratinocytes (HaCaT). Platycodin D-induced apoptosis in HaCaT cells was confirmed by DNA fragmentation, caspase-3 activation, and caspase-8 activation. Platycodin D could activate inhibitor of nuclear factor-κB kinase (IKK)-β in the nuclear factor-kappaB (NF-κB) activation of upstream level, but not IKK-α. Pretreated-N-tosyl-l-phenylalanine chloromethyl ketone (TPCK), a potent NF-κB inhibitor, could suppress the induction of apoptosis and activation of NF-κB of HaCaT cells by platycodin D. We also demonstrated that platycodin D-mediated apoptosis of HaCaT cells upregulates Fas receptor and Fas ligand (FasL) expression, but did not exhibit p53 activation. HaCaT cells were also transfected with pFLF1, which preserves the promoter region of Fas receptor gene containing NF-κB binding site. On incubation with platycodin D, the NF-κB activity related to Fas receptor increased in a dose-dependent manner. Among the major transcription elements on Fas receptor and FasL promoter, NF-κB activation was shown to have an essential role in the expression of the death receptor such as FasL. These results suggest that platycodin D has the ability to induce apoptosis in HaCaT cells through the upregulation of Fas receptor and FasL expression via to NF-κB activation in the transcriptional level. These results demonstrate that the NF-κB activation plays a crucial role in the induction of apoptosis in human HaCaT cells on treatment with platycodin D. [Copyright &y& Elsevier]

Stimulation of cells with tumor necrosis factor-α (TNF-α) results in the increase in generation of H2O2 in mitochondria that leads to apoptosis. The effect of H2O2 produced by TNF-α on the redox status of selenocysteine (SeCys) residue essential for mitochondrial thioredoxin reductase (TrxR2) was investigated in HeLa cells. TNF-α caused accumulation of oxidized TrxR2 with a thioselenide bond. The conditional induction of SeCys-deficient TrxR2 resulted in the increased production of H2O2 and apoptosis. These results suggest that the SeCys residue of TrxR2 plays a critical role in cell survival by serving as an electron donor for Trx-II and subsequent peroxiredoxin-III, which is a primary line of defense against H2O2 in mitochondria. [Copyright &y& Elsevier]

Aberrant activation of signal transducer and activator of transcription 3 (STAT3) has been documented in various malignancies including triple-negative breast cancers (TNBCs). The STAT3 transcription factor can regulate the different important hallmarks of tumor cells, and thus, targeting it can be a potential strategy for treating TNBC, for which only limited therapeutic options are available. In this study, we analyzed the possible effect of (-)-galiellalactone and its novel analogues, SG-1709 and SG-1721, and determined whether these agents exerted their antineoplastic effects by suppressing the STAT3 signaling pathway in TNBC cells. The two analogues, SG-1709 and SG-1721, inhibited both constitutive as well as inducible STAT3 phosphorylation at tyrosine 705 more effectively than (-)-galiellalactone, which indicates that the analogues are more potent STAT3 blockers. Moreover, SG-1721 not only inhibited nuclear translocation and DNA binding of STAT3 but also induced apoptosis, and decreased expression of diverse oncogenic proteins. Interestingly, SG-1721 also exhibited an enhanced apoptotic effect when combined with radiotherapy. Furthermore, in vivo administration of SG-1721 significantly attenuated breast xenograft tumor growth via decreasing levels of p-STAT3. Therefore, SG-1721 may be a promising candidate for further application as a pharmacological agent that can target STAT3 protein in treating TNBC. [ABSTRACT FROM AUTHOR]