Independent Apoptosis Pathways Research Articles

Abstract P2-26-19: Slc26a9 cooperates with HER2 to regulate the progression and development of HER2-positive breast cancer

Abstract Goals: Ion transporters play an important regulatory role in the progression and development of breast cancer (BC). Slc26a9 is a member of the Slc26a anion transporter family, which is mainly involved in regulating the secretion of chloride ions and bicarbonate, but the role of Slc26a9 in HER2-positive BC is still unclear. Methods: Tissue microarray and BC cell line were used to detect the expression level of Slc26a9 and its clinical relevance. By changing the expression level of Slc26a9 gene in BC cells, the effect of Slc26a9 gene on the biological behavior of BC cells and its related molecular mechanism were discussed. Results: We found that the expression of Slc26a9 was significantly upregulated in BC compared with adjacent tissues, and the upregulated Slc26a9 was associated with TNM staging and poor prognosis in BC patients. In addition, the expression of Slc26a9 was significantly upregulated in HER2-positive BC compared with HER2-negative BC, and similar results were obtained in BC cell lines, with Slc26a9 was the highest expression in HER2-enriched SKBR3 cells. Functionally, the proliferation, migration, invasion and anti-apoptotic abilities of SKBR3 cells were significantly inhibited after silencing Slc26a9, and tumorigenesis and metastasis were significantly inhibited in vivo. On the contrary, overexpression of Slc26a9 resulted in the opposite result. Mechanistically, overexpression of Slc26a9 activated the PI3K/AKT/mTOR signaling pathway, the key signaling pathway implicated in HER2-positive breast carcinogenesis, and promoted the expression of downstream proliferation related genes CCND1 (Cyclin D1) and c-Myc, and downregulated the expression of apoptosis related genes Caspase9, apoptosis-inducing factor (AIF) and endonuclease G (Endo G), indicating the simultaneous inhibition of caspase dependent and independent apoptosis pathway. At the same time, accompanied by changes in markers of epithelial-mesenchymal transition (EMT), including downregulation of E-cadherin and ZO-1, and upregulation of N-cadherin and Fibronectin, and SKBR3 cells changed from epithelioid morphology to mesenchymal morphology. In addition, immunofluorescence and protein nucleoplasm separation experiments showed that Slc26a9 upregulated the expression of HER2 and co-localized with HER2 in the nucleus. Co-immunoprecipitation experiments proved that Slc26a9 interacted with HER2. Furthermore, trastuzumab downregulated the expression of Slc26a9 by targeting HER2 in SKBR3 cells. Moreover, when Slc26a9 was overexpressed, the inhibitory effect of trastuzumab on HER2 was partially reversed, and we also verified the PI3K/AKT/mTOR signaling pathway. Not only that, we found that Slc26a9 was significantly upregulated in drug-resistant cell lines relative to parental cells by constructing SKBR3 drug-resistant cell lines, indicating that Slc26a9 expression was significantly correlated with chemotherapy resistance in HER2-positive BC. Conclusion(s): Slc26a9 may interact with HER2 in the form of molecular chaperones to activate PI3K/AKT/mTOR signaling pathway to promote the progression and development of HER2-positive BC and be associated with chemotherapy resistance, but the precise molecular mechanism needs further exploration. Conflict of Interest: No significant relationships. Citation Format: Zhengxing Zhou, Zhiyuan Ma, Xuemei Liu, Chengmin Zhang, Hu Wang, Renmin Mu, Xiaoming Cheng, Biguang Tuo, Taolang Li. Slc26a9 cooperates with HER2 to regulate the progression and development of HER2-positive breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-26-19.

Chlorpyrifos induces neuronal cell death via both oxidative stress and Akt activation downstream-regulated CHOP-triggered apoptotic pathways

Chlorpyrifos (CPF) is one of the most abundant and widely used organophosphate pesticides for agricultural, industrial, and household purposes in the world. Epidemiological studies have reported that CPF can induce neurotoxic impairments in mammalian, which is linked to an important risk factor for development of neurodegenerative diseases (NDs). However, limited information is available on CPF-induced neurotoxicity, with the underlying exact mechanism remains unclear. In this study, CPF exposure (10–400 μM) significantly reduced Neuro-2a cell viability and induced apoptotic events, including the increase in caspase-3 activity, apoptotic cell population, and cleavage of caspase-3/−7 and PARP. Exposure of Neuro-2a cells to CPF also triggered CHOP activation. Transfection with CHOP-specific siRNA markedly suppressed the expression of CHOP, and attenuated cytotoxicity and apoptotic events in CPF-exposed Neuro-2a cells. Furthermore, CPF exposure obviously evoked the phosphorylation of Akt as well as ROS generation in a time-dependent manner. Pretreatment with LY294002 (an Akt inhibitor) effectively attenuated the CPF-induced Akt phosphorylation, CHOP activation, and apoptotic events, but not that ROS production. Of note, buffering the ROS generation with antioxidant N-acetylcysteine effectively prevented the CPF-induced ROS generation, CHOP activation, and apoptotic events, but not that the Akt phosphorylation. Collectively, these findings indicate that CPF exposure exerts neuronal cytotoxicity via the independent pathways of ROS generation and Akt activation downstream-regulated CHOP-triggered apoptosis, ultimately leading to neuronal cell death.

Synthesis and antitumor activity of a series of novel N-aryl-5-(2,2,2-trifluoroethoxy)-1,5-dihydro-2H-pyrrol-2-ones derivatives

With the help of the establishment of novel reaction methodology, a series of N-Aryl-5-(2,2,2-trifluoroethoxy)-1,5-dihydro-2H-pyrrol-2-one conjugates were designed and synthesized in 2–4 steps, and subsequent anticancer activity of these compounds was evaluated. Preliminary results showed that these compounds have moderate to potent activities against human acute leukemia cells K562, human lung cancer A549, human breast cancer MDA-MB-231, and human cervical cancer HeLa cancer cell lines. Among them, compounds 2d and 2k were the most potent against K562 cell line with IC50 values of 0.07 and 0.52 µM, respectively, and the toxicity of 2d to the normal of hepatocytes (LO2) cell line was low (the survival rate 81 %). Flow cytometry analysis showed that 2d arrested K562 cells in the G2/M phase potently, even much better than Combretastatin A4 (CA4). In addition, the results demonstrated the involvement of the caspase-dependent or independent pathways of apoptosis, evidenced by the upregulation of FADD, pro-caspase 3, cleaved-caspase 3, HTRA2/Omi, SMAC/Diablo and the ratio of Bax/Bcl-2.The biological effects founding of 2d in this work point to prospective uses against acute leukemia.

Extract Derived from Cedrus atlantica Acts as an Antitumor Agent on Hepatocellular Carcinoma Growth In Vitro and In Vivo.

Cedrus atlantica is widely used in herbal medicine. However, the anti-cancer activity of C. atlantica extract (CAt extract) has not been clarified in hepatocellular carcinoma. In the study, we elucidated the anti-hepatoma capacity of CAt extract on HCC in vitro and in vivo. To explore the anti-hepatoma mechanisms of the CAt extract in vitro, HCC and normal cells were treated with the CAt extract, which showed marked inhibitory effects on HCC cells in a dose-dependent manner; in contrast, the CAt extract treatment was less cytotoxic to normal cells. In addition, our results indicate that the CAt extract induced apoptosis via caspase-dependent and independent apoptosis pathways. Furthermore, the CAt extract inhibited HCC tumor cell growth by restraining cell cycle progression, and it reduced the signaling of the AKT, ERK1/2, and p38 pathways. In the xenograft model, the CAt extract suppressed HCC tumor cell growth and prolonged lifespan by inhibiting PCNA protein expression, repressing part of the VEGF-induced autocrine pathway, and triggering strong expression of cleaved caspase-3, which contributed to cell apoptosis. Moreover, the CAt extract did not induce any obvious changes in pathological morphology or body weight, suggesting it had no toxicity. CAt extract exerted anti-tumor effects on HCC in vitro and in vivo. Thus, CAt extract could be used as a potential anti-cancer therapeutic agent against HCC.

Solid state fermentation process with Aspergillus kawachii enhances the cancer-suppressive potential of silkworm larva in hepatocellular carcinoma cells

BackgroundMulberry silkworm larvae (Bombyx mori) are known as the oldest resource of food and traditional medicine. Although silkworm larvae have been reported to treat various chronic diseases, the effect of fermentation by microorganisms improving the biological activities of silkworm larvae was not reported. In the present study, fermented silkworm larvae was developed via solid-state fermentation with Aspergillus kawachii and investigated its anti-cancer activity in human hepatocellular carcinoma cells.MethodsWe investigated the anti-cancer effects of unfermented (SEE) and fermented silkworm larva ethanol extract (FSEE) on HepG2 human hepatocellular carcinoma cells as well as compared changes in free amino acid, fatty acid, and mineral contents. Anti-cancer activities were evaluated by SRB staining, cell cycle analysis, Annexin V staining, Hoechst staining, DNA fragmentation analysis and western blot analysis. Fatty acid, free amino acid and mineral contents of SEE and FSEE were determined by gas chromatography, amino acid analyzer and flame atomic absorption spectrophotometer, respectively.ResultsCompared with SEE, treatment with FSEE resulted in apoptotic cell death in HepG2 cells characterized by G0/G1 phase cell cycle arrest, DNA fragmentation, and formation of apoptotic bodies. Furthermore, FSEE significantly up-regulated pro-apoptotic as well as down-regulated anti-apoptotic proteins in HepG2 cells. However, an equivalent concentration of SEE did not induce cell cycle arrest or apoptosis in HepG2 cells. Moreover, fermentation process by Aspergillus kawachii resulted in enhancement of fatty acid contents in silkworm larvae, whereas amino acid and mineral contents were decreased.ConclusionCollectively, this study demonstrates that silkworm larvae solid state-fermented by Aspergillus kawachii strongly potentiates caspase-dependent and -independent apoptosis pathways in human hepatocellular carcinoma cells by regulating secondary metabolites.

Tailoring Biomolecular Interactions of Hybrid Nanostructures for their Diagnostic and Therapeutic Applications in Neurodegenerative Diseases

Alzheimer and Parkinson disease are common neurodegenerative disorders characterized by progressive structural and functional loss of the central nervous system. The foremost neuropathological events involve oxidative stress, mitochondrial dysfunction, inflammation and apoptosis. The disease-specific proteinopathies consists soluble aggregates including oligomers and protofibrils along with their phosphorylated variants deposited as plaque. The dynamic adsorption of these proteins on nanoparticle surface bestows with different physicochemical features and elicits the biological response. We show, in our approach molecular chemistry and optical characteristics of curcumin were used to elucidate the lanthanum carbonate nanospheres (REM100) and protein interactions via spontaneous binding of Aβ monomer and Aβ aggregates on Curcumin-REM100. The Protein concentration-dependent steady-state fluorescence enhancement of the curcumin and Langmuir protein adsorption model elucidates the maximum surface coverage and an apparent dissociation constant. Based on all experimental outcomes we demonstrated curcumin-REM100 as an efficient fluorescent probe able to delineate the monomer and the aggregate state of Amyloid-β with the Limit of detection (LOD) of 0.2 ±0.045 μM, the value is 30 times more sensitive than conventional Thioflavin-T (ThT) fluorescence emission intensity. The therapeutic approach uses the melatonin enriched polydopamine nanostructures for triggering robust neuroprotection against rotenone-induced neuroblastoma PD model. This causes reduction in cellular ROS level, re-establishing mitochondrial membrane potential, inhibiting caspase-dependent and independent apoptosis pathway and reducing alpha-synuclein phosphorylation at serine 129. The further in-vitro and organotypic mice brain slice culture-based therapeutic assessments have shown the superior neuroprotective potential of the developed nanoformulation. Considering the emerging interest in development of hybrid nanoformulation, our approaches elucidated diagnostic and therapeutic interventions in common neurodegenerative diseases.

Lack of the brain-specific isoform of apoptosis-inducing factor aggravates cerebral damage in a model of neonatal hypoxia\u2013ischemia

Apoptosis-inducing factor (AIF) may contribute to neuronal cell death, and its influence is particularly prominent in the immature brain after hypoxia–ischemia (HI). A brain-specific AIF splice-isoform (AIF2) has recently been discovered, but has not yet been characterized at the genetic level. The aim of this study was to determine the functional and regulatory profile of AIF2 under physiological conditions and after HI in mice. We generated AIF2 knockout (KO) mice by removing the AIF2-specific exon and found that the relative expression of Aif1 mRNA increased in Aif2 KO mice and that this increase became even more pronounced as Aif2 KO mice aged compared to their wild-type (WT) littermates. Mitochondrial morphology and function, reproductive function, and behavior showed no differences between WT and Aif2 KO mice. However, lack of AIF2 enhanced brain injury in neonatal mice after HI compared to WT controls, and this effect was linked to increased oxidative stress but not to caspase-dependent or -independent apoptosis pathways. These results indicate that AIF2 deficiency exacerbates free radical production and HI-induced neonatal brain injury.

The Role of Caspase-3, Apoptosis-Inducing Factor, and B-cell Lymphoma-2 Expressions in Term Premature Rupture of Membrane.

To determine the role of caspase-3, apoptosis-inducing factor (AIF), and B-cell lymphoma-2 (Bcl-2) expressions in term premature rupture of membrane (PROM). An analytic observational study with case-control design was conducted, involving 52 subjects (37-42 weeks of gestation) who were divided into 2 groups: 26 cases of term delivery with PROM, and 26 controls of term delivery without PROM. The expressions of caspase-3, AIF, and Bcl-2 in the amniotic membrane were determined by immunohistochemistry. Data were analyzed using the chi-squared test. The risk of PROM was expressed by odds ratio (OR). There were no significant differences in age, parity and body mass index between the two groups (p > 0.05). High caspase-3 and AIF expressions increased the risk of PROM 17.64 times (OR = 17.64; 95% CI = 4.44-70.07; p = 0.001) and 9.45 times (OR = 9.45; 95% CI= 2.62-34.07; p = 0.001), respectively, while low Bcl-2 expression increased 10.39 times (OR = 10.39; 95% CI = 2.73-39.56; p = 0.001)the risk of PROM . High caspase-3 and AIF expressions and low Bcl-2 expression were risk factors for term PROM. Caspase-dependent and independent pathways of apoptosis were involved in the mechanism of PROM in term pregnancy.

Dimethyl Oxalyl Glycine a Prolyl Hydroxylase Inhibitor Decreases Early Gastrointestinal Gvhd Via Two Independent Pathways of Apoptosis after Allogeneic Hematopoietic Cell Transplantation

Introduction: Allogeneic hematopoietic cell transplantation (HCT) is increasingly utilized in the treatment of hematologic malignant and non-malignant diseases. Therapy-related toxicity and graft versus host disease (GVHD) remain major challenges as they significantly contribute to treatment related morbidity and mortality. Prolyl hydroxylase inhibitors (PHI) interfere with signaling cascades of inflammation and cell death. Their beneficial use in experimental models of ulcerative colitis and lung allograft rejection resulted in the hypothesis, that use of the PHI dimethyl oxalyl glycine (DMOG) reduces GVHD after murine allogeneic HCT. We already showed that DMOG treatment of allogeneic recipients resulted in significantly improved survival by day +50 compared to allogeneic controls, and was associated with significant decrease in organ pathology and proinflammatory cytokines (data not shown). We now expanded our study to better understand the underlying mechanisms for this observation.Methods: Acute GVHD was induced in lethally irradiated BALB/c mice followed by the infusion of 5 million bone marrow cells mixed with 4 million splenocytes from allogeneic C57BL/6 donors. DMOG dissolved in PBS was given at 8mg per mice intraperitoneally while controls received PBS only. Animals were monitored for clinical GVHD and survival and analyzed at day +7 and at day +50 post HCT. Formalin-fixed paraffin sections were processed for immunohistochemistry with CD3, Hif-1 alpha, or FADD pSer191 antibodies. Western blot analysis was performed after CD3/CD28 antibody activation of T cells to see the effect of DMOG treatment on Hif-1 α expression. Effect of DMOG on apoptosis and CD137 expression was analyzed by flow cytometry.Results: Our results demonstrate that the protective effect of DMOG is mainly caused by two independent pathways of apoptosis. DMOG treatment of allogeneic recipients resulted in decreased T cells infiltration (p=0.0534) and (Fas associated death domain) FADDpSer191 level (p<0.05) in small intestine sections at day +50. Decreased FADD pSer191 indicates decreased TNF-a induced epithelial cell apoptosis. This was associated with increased Hif1- α expression at day+7 (p<0.05) as well day+50 (p<0.05) as shown by histochemical analysis of small intestine sections. DMOG treatment of activated T cells showed increased expression of CD137 (p<0.005) and Annexin V FITC (p<0.005) staining suggesting that DMOG subjects T cells to activation induced cell death (AICD) via induced CD137 expression. Microscopic scanning of DMOG treated T cells showed condensed chromatin along with numerous fragmented nuclei, indicative of apoptotic cell. In vitro proliferative T cell responses were suppressed (p<0.05) in the presence of DMOG in a dose-dependent manner along with increase in Hif1- α level (p<0.05) as analyzed by western blot.Conclusion: Our data demonstrates protective effects of DMOG on the GI tract early after allogeneic HCT which is associated with improved survival and reduced lung injury at later time point. DMOG treatment results in the induction of CD137 on T cells subjecting them to AICD and represses FADD level in epithelial cells regulating their apoptosis. Taken together, DMOG treatment reduces GVHD via a two pronged mechanism, possibly allowing for novel strategies to prevent and treat this deleterious disease. DisclosuresPalaniyandi:Pharmacyclics: Research Funding; Takeda Pharmaceutical International, Inc.: Research Funding; JAZZ: Research Funding.

Artocarpin, an isoprenyl flavonoid, induces p53-dependent or independent apoptosis via ROS-mediated MAPKs and Akt activation in non-small cell lung cancer cells.

Artocarpin has been shown to exhibit cytotoxic effects on different cancer cells, including non-small cell lung carcinoma (NSCLC, A549). However, the underlying mechanisms remain unclear. Here, we explore both p53-dependent and independent apoptosis pathways in artocarpin-treated NSCLC cells. Our results showed that artocarpin rapidly induced activation of cellular protein kinases including Erk1/2, p38 and AktS473. Inhibition of these protein kinases prevented artocarpin-induced cell death. Moreover, artocarpin-induced phosphorylation of these protein kinases and apoptosis were mediated by induction of reactive oxygen species (ROS), as pretreatment with NAC (a ROS scavenger) and Apocynin (a Nox-2 inhibitor) blocked these events. Similarly, transient transfection of p47Phox or p91Phox siRNA attenuated artocarpin-induced NADPH oxidase activity and cell death. In addition, p53 dependent apoptotic proteins including PUMA, cytochrome c, Apaf-1 and caspase 3 were activated by artocarpin, and these effects can be abolished by antioxidants, MAPK inhibitors (U0126 and SB202190), but not by PI3K inhibitor (LY294002). Furthermore, we found that artocarpin-induced Akt phosphorylation led to increased NF-κB activity, which may act as an upstream regulator in the c-Myc and Noxa pathway. Therefore, we propose that enhancement of both ERK/ p38/ p53-dependent or independent AktS473/NF-κB/c-Myc/Noxa cascade by Nox-derived ROS generation plays an important role in artocarpin-induced apoptosis in NSCLC cells.

Critical role of reactive oxygen species (ROS) for synergistic enhancement of apoptosis by vemurafenib and the potassium channel inhibitor TRAM-34 in melanoma cells

Inhibition of MAP kinase pathways by selective BRAF inhibitors, such as vemurafenib and dabrafenib, have evolved as key therapies of BRAF-mutated melanoma. However, tumor relapse and therapy resistance have remained as major problems, which may be addressed by combination with other pathway inhibitors. Here we identified the potassium channel inhibitor TRAM-34 as highly effective in combination with vemurafenib. Thus apoptosis was significantly enhanced and cell viability was decreased. The combination vemurafenib/TRAM-34 was also effective in vemurafenib-resistant cells, suggesting that acquired resistance may be overcome. Vemurafenib decreased ERK phosphorylation, suppressed antiapoptotic Mcl-1 and enhanced proapoptotic Puma and Bim. The combination resulted in enhancement of proapoptotic pathways as caspase-3 and loss of mitochondrial membrane potential. Indicating a special mechanism of vemurafenib-induced apoptosis, we found strong enhancement of intracellular ROS levels already at 1 h of treatment. The critical role of ROS was demonstrated by the antioxidant vitamin E (α-tocopherol), which decreased intracellular ROS as well as apoptosis. Also caspase activation and loss of mitochondrial membrane potential were suppressed, proving ROS as an upstream effect. Thus ROS represents an initial and independent apoptosis pathway in melanoma cells that is of particular importance for vemurafenib and its combination with TRAM-34.

Maternal Omega-3 Supplement Improves Dopaminergic System in Pre- and Postnatal Inflammation-Induced Neurotoxicity in Parkinson's Disease Model.

Evidence suggests that idiopathic Parkinson's disease (PD) is the consequence of a neurodevelopmental disruption, rather than strictly a consequence of aging. Thus, we hypothesized that maternal supplement of omega-3 polyunsaturated fatty acids (ω-3 PUFA) may be associated with neuroprotection mechanisms in a self-sustaining cycle of neuroinflammation and neurodegeneration in lipopolysaccharide (LPS)-model of PD. To test this hypothesis, behavioral and neurochemical assay were performed in prenatally LPS-exposed offspring at postnatal day 21. To further determine whether prenatal LPS exposure and maternal ω-3 PUFAs supplementation had persisting effects, brain injury was induced on PN 90 rats, following bilateral intranigral LPS injection. Pre- and postnatal inflammation damage not only affected dopaminergic neurons directly, but it also modified critical features, such as activated microglia and astrocyte cells, disrupting the support provided by the microenvironment. Unexpectedly, our results failed to show any involvement of caspase-dependent and independent apoptosis pathway in neuronal death mechanisms. On the other hand, learning and memory deficits detected with a second toxic exposure were significantly attenuated in maternal ω-3 PUFAs supplementation group. In addition, ω-3 PUFAs promote beneficial effect on synaptic function, maintaining the neurochemical integrity in remaining neurons, without necessarily protect them from neuronal death. Thus, our results suggest that ω-3 PUFAs affect the functional ability of the central nervous system in a complex way in a multiple inflammation-induced neurotoxicity animal model of PD and they disclose new ways of understanding how these fatty acids control responses of the brain to different challenges.

Vitamin D/VDR signaling pathway ameliorates 2,4,6-trinitrobenzene sulfonic acid-induced colitis by inhibiting intestinal epithelial apoptosis.

Increasing epidemiological data have suggested a link between vitamin D deficiency and the incidence of inflammatory bowel disease (IBD). In the present study, we confirmed that vitamin D deficiency, as well as the decreased local expression of vitamin D receptor (VDR), was prevalent in an IBD cohort. The excessive apoptosis of intestinal epithelial cells (IECs) partly accounts for the development of colonic inflammation and eventually results in IBD. Based on the established inhibitory effects of the vitamin D/VDR pathway on IEC apoptosis, we treated mice with 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis with paricalcitol, a vitamin D analog, in order to investigate the mechanisms responsible for the inhibitory effects of the vitamin D/VDR pathway. We observed that following treatment with vitamin D, the mice presented with only minor bodyweight loss, and the mice also showed improved histological scores and decreased intestinal epithelial permeability compared with the vehicle-treated group. The colonic mRNA expression of inflammatory cytokines and chemokines was markedly suppressed, indicating less severe colitis in the vitamin D-treated mice. Subsequently, we investigated p53 upregulated modulator of apoptosis (PUMA) and p53, two major independent pathways of apoptosis, as well as caspase-3. We found that the vitamin D-treated mice had lower expression levels of caspase-3 than the vehicle-treated mice. PUMA expression showed the same tendency; however, the p53 protein level was not altered. The present study indicates that vitamin D attenuates the development of TNBS-induced colitis by inhibiting the apoptosis of IECs. The mechanisms involved include the downregulation of PUMA expression. Our data provide experimental support for the clinical trials of vitamin D intervention in patients with IBD.

Curcumin enhances recovery of pancreatic islets from cellular stress induced inflammation and apoptosis in diabetic rats

The phytochemical, curcumin, has been reported to play many beneficial roles. However, under diabetic conditions, the detail mechanism of its beneficial action in the glucose homeostasis regulatory organ, pancreas, is poorly understood. The present study has been designed and carried out to explore the role of curcumin in the pancreatic tissue of STZ induced and cellular stress mediated diabetes in eight weeks old male Wistar rats. Diabetes was induced with a single intraperitoneal dose of STZ (65mg/kg body weight). Post to diabetes induction, animals were treated with curcumin at a dose of 100mg/kg body weight for eight weeks. Underlying molecular and cellular mechanism was determined using various biochemical assays, DNA fragmentation, FACS, histology, immunoblotting and ELISA. Treatment with curcumin reduced blood glucose level, increased plasma insulin and mitigated oxidative stress related markers. In vivo and in vitro experimental results revealed increased levels of proinflammatory cytokines (TNF-α, IL1-β and IFN-γ), reduced level of cellular defense proteins (Nrf-2 and HO-1) and glucose transporter (GLUT-2) along with enhanced levels of signaling molecules of ER stress dependent and independent apoptosis (cleaved Caspase-12/9/8/3) in STZ administered group. Treatment with curcumin ameliorated all the adverse changes and helps the organ back to its normal physiology. Results suggest that curcumin protects pancreatic beta-cells by attenuating inflammatory responses, and inhibiting ER/mitochondrial dependent and independent pathways of apoptosis and crosstalk between them. This uniqueness and absence of any detectable adverse effect proposes the possibility of using this molecule as an effective protector in the cellular stress mediated diabetes mellitus.

Hyperammonia induces specific liver injury through an intrinsic Ca2+-independent apoptosis pathway.

BackgroundNumerous pathological processes that affect liver function in patients with liver failure have been identified. Among them, hyperammonia is one of the most common phenomena.The purpose of this study was to determine whether hyperammonia could induced specific liver injury.MethodsHyperammonemic cells were established using NH4Cl. The cells were assessed by MTT, ELISA, and flow cytometric analyses. The expression levels of selected genes and proteins were confirmed by quantitative RT-PCR and western blot analyses.ResultsThe effects of 20 mM NH4Cl pretreatment on the cell proliferation and apoptosis of primary hepatocytes and other cells were performed by MTT assays and flow cytometric analyses. Significant increasing in cytotoxicity and apoptosis were only observed in hepatocytes. The cell damage was reduced after adding BAPTA-AM but unchanged after adding EGTA. The expression levels of caspase-3, cytochrome C, calmodulin, and inducible nitric oxide synthase were increased and that of bcl-2 was reduced. The Na+-K+-ATPase activities in hyperammonia liver cells was no signiaficant difference compaired with the control group, but was decreased in astrocytes. NH4Cl pretreatment of primary hepatocytes promoted the activation of mitochondrial permeability transition pores and the mitochondria swelled irregularly.ConclusionsHyperammonia induces specific liver injury through an intrinsic Ca2+-independent apoptosis pathway.

Interaction of Leukocyte Elastase Inhibitor/L-DNase II with BCL-2 and BAX

Leukocyte Elastase Inhibitor (LEI, also called serpin B1) is a protein involved in apoptosis among other physiological processes. We have previously shown that upon cleavage by its cognate protease, LEI is transformed into L-DNase II, a protein with a pro-apoptotic activity. The caspase independent apoptotic pathway, in which L-DNase II is the final effector, interacts with other pro-apoptotic molecules like Poly-ADP-Ribose polymerase (PARP) or Apoptosis Inducing Factor (AIF). The screening of LEI/L-DNase II interactions showed a possible interaction with several members of the BCL-2 family of proteins which are known to have a central role in the regulation of caspase dependent cell death. In this study, we investigated the regulation of LEI/L-DNase II pathway by two members of this family of proteins: BAX and BCL-2, which have opposite effects on cell survival. We show that, in both BHK and HeLa cells, LEI/L-DNase II can interact with BCL-2 and BAX in apoptotic and non-apoptotic conditions. These proteins which are usually thought to be anti-apoptotic and pro-apoptotic respectively, both inhibit the L-DNase II pro-apoptotic activity. These results give further insight in the regulation of caspase independent pathways and highlight the involvement of the intracellular environment of a given protein in the determinism of its function. They also add a link between caspase-dependent and independent pathways of apoptosis.

294 Conditional Intestine-Specific HuR Deletion (HuR-IKO) Modulates Distinct Wnt-Dependent and Independent Pathways of Proliferation and Apoptosis With No Effect on Ileal ASBT Expression or Bile Acid Metabolism

Acute gut mucosal injury occurs commonly during critical pathological conditions, leading to mucosal hemorrhage, epithelial barrier dysfunction, and the translocation of luminal toxic substances and bacteria to the blood stream, but the exact mechanism underlying mucosal injury/repair are still obscure. RNA-binding proteins (RBPs) posttranscriptionally regulate gene expression and are implicated in many aspects of pathophysiology. HuR is among the most prominent sequence-specific RBP and has emerged as a master regulator of the maintenance of the homeostasis of gut mucosa. Our previous studies show that HuR regulates intestinal epithelial cell proliferation and apoptosis, but the exact role of HuR in gut mucosal repair after injury remains unknown. This study tested the hypothesis that HuR plays a role in intestinal mucosal repair after ischemia/reperfusion (I/R)-induced Injury.Methods: Studies were conducted in our recently generating intestinal epithelial tissue-specific HuR knockout (IE-HuR-/-) mice and wild-type littermates. Mucosal injury was induced by exposed to 30min of mesenteric ischemia, followed by 2-h reperfusion. Barrier function was detected by paracellular tracer flux assay using FITC-dextran. Results: The mucosa of the animals subjected to mesenteric I/R displayed signs of remarkable damage. Macroscopically, the intestines of the animals exposed to I/R exhibited swollen and edematous with areas of red streaks in both littermates and IE-HuR-/animals. Microscopic analysis showed that there were severed damages in the small intestinal mucosa as indicated by sloughed cells, denuded villi with dilated capillaries, and frank hemorrhage. Although there were no significant differences in the injury scores between littermates and IE-HuR-/mice when measured immediately after I/R, HuR deletion delayed the process of early mucosal repair after I/Rinduced injury. The mucosal surface remained discontinuous, showing sloughed cells and debris in IE-HuR-/mice (injury score: 3.3 ± 0.12) 6 h after I/R, whereas the mucosa in littermates was almost completely recovered (0.2 ± 0.03). Both littermate and IE-HuR-/mice exhibited significant gut barrier dysfunction after I/R-induced injury, but increased levels of gut permeability in IE-HuR-/mice were much greater than those observed in littermates. The recovery of gut barrier function after I/R was also inhibited by HuR deletion. Moreover, expression of the Wnt co-receptor LRP6 and ARP2 in the intestinal mucosa of HuR-/mice decreased dramatically, which are necessary for normal mucosal repair after injury. Conclusions: These results indicate that 1) HuR is crucial for maintenance of normal gut mucosal epithelial integrity and 2) HuR deletion in intestinal epithelial cells delays mucosal repair and represses the recovery of gut barrier function after I/R-induced mucosal injury.

Tetrandrine and Caffeine Modulated Cell Cycle and Increased Glioma Cell Death via Caspase-Dependent and Caspase-Independent Apoptosis Pathways

Viability, cell cycle distribution, and expressions of eukaryotic translation initiation factor-2α (eIF-2α), cyclin D1, poly(ADP-ribose) polymerase 1 (PARP-1), and apoptosis-inducing factor (AIF) of RT-2 glioma cells were assayed under treatment of tetrandrine and caffeine for 48 h. The results showed that cell viability decreased significantly under treatment with tetrandrine (5 μM) alone or under combined treatment with tetrandrine (5 μM) and caffeine (0.5 or 1 mM). The ratio of RT-2 cells at sub G1 and G0/G1 stages increased significantly during combined treatment of tetrandrine (5 μM) and caffeine (0.5, 1 mM). The ratio of phospharylated eIF-2α to dephospharylated eIF-2α increased, whereas cyclin D1 decreased significantly under combined treatment of tetrandrine (5 μM) and caffeine (1 mM). The cleaved PARP-1 to PARP-1 ratio was elevated significantly under treatment of 5 μM tetrandrine alone, and combined treatment of 5 μM tetrandrine and caffeine (0.5, 1 mM). The expression levels of AIF increased significantly under treatment of 5 μM tetrandrine alone or 1 mM caffeine alone, and combined treatment of 5 μM tetrandrine and caffeine (0.5, 1 mM). In conclusion, tetrandrine and caffeine could induce glioma cell death possibly via increasing eIF-2α phospharylation, decreasing cyclin-D1 expression, and increasing caspase-dependent and -independent apoptosis pathways.

Combretastatin A‐4 induces p53 mitochondrial‐relocalisation independent‐apoptosis in non‐small lung cancer cells

Combretastatin A-4 (CA-4) is one of the most effective agents used in chemotherapy. Nevertheless, the contribution of p53 and Bim proteins in the CA-4-induced apoptosis in non-small lung cancer cells (NSCLC) remains unresolved, specifically on involving of p53 in the mitochondrial pathway activation by a transcription-independent mechanism. In this context, the p53-null H1299 and wt-p53 H460 NSCLC cells, in the absence and presence of pifithrin-µ (PFTµ), an inhibitor of p53 mitochondrial-translocation, were treated with CA-4 and different cellular endpoints were analysed. In contrast to previous observations in H460 cells, CA-4 failed in the activation of an apoptotic response in H1299 cells, thus indicating an involvement of p53 in the cell death induced by the drug. We found that CA-4 led to p53 cellular re-localisation in H460 cells; in particular, p53 was released from the microtubular network and accumulated at mitochondria where it interacts with Bim protein and other proteins of the Bcl-2 (B-cell leukaemia-2) family, leading to cytochrome c release, alteration in the mitochondrial membrane polarisation, cell cycle arrest at the G2/M-phase, and cell death. Interestingly, the cytosolic and the mitochondrial accumulation of protein Bim was strictly dependent on p53 status. The extent of cell death was not reduced in H460 after combined treatment of PFTµ with CA-4. Overall, the data support a model of CA-4-induced apoptosis in NSCLC, for which the expression of p53 protein is essential, but its mitochondrial function, linked to p53-transcription independent apoptosis pathway, is negligible.

Protective Effect of Minocycline Against Cisplatin-induced Ototoxicity

ObjectivesCisplatin, a widely used chemotherapeutic agent, has serious side effects, including nephrotoxicity and ototoxicity. Minocycline is a semisynthetic second-generation tetracycline that exerts anti-inflammatory and neuroprotective effects. The purpose of this study was to elucidate the protective effect of minocycline against cisplatin-induced ototoxicity in the auditory hair cell.MethodsThe House Ear Institute-Organ of Corti 1 (HEI-OC1) cell line and guinea pigs were used for in vitro and in vivo experiments. Cells were exposed to cisplatin with or without pre-treatment with minocycline. Cell survival was analyzed using MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide). Whole-cell lysates were collected and immunoblotted with antibodies against Bcl-2, p-c-Jun, active caspase-3, cleaved poly (ADP-ribose) polymerase (PARP), and apoptosis-inducing factor (AIF). The guinea pigs received intraperitoneal injections of cisplatin alone or following minocycline pretreatment. The auditory brainstem response was tested and the cochleae were harvested and evaluated using scanning electron microscopy.ResultsSurvival significantly increased in cells pretreated with minocycline compared with cells exposed to cisplatin alone. Cisplatin treatment increased the expression of active caspase 3, p-c Jun, PARP, and AIF, and pretreatment with minocycline attenuated this response. In animal study, the threshold shift by cisplatin injection in the auditory brainstem response was less pronounced in animals pretreated with minocycline. Scanning electron microscopy revealed more severe damage to the outer hair cells at the basal and middle turns than the apical turn.ConclusionMinocycline partially protects against cisplatin-induced ototoxicity via both caspase-dependent and independent apoptosis pathways.