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At least 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Influence of computed tomography contrast agent on radiotherapy dose calculation for pancreatic carcinoma: A dosimetric study based on tomotherapy and volumetric-modulated arc therapy techniques

The main purpose of our investigation was to quantify the dosimetric influence of intravenous contrast agent for pancreatic cancer radiotherapy treatment. This study focused on complex modulated irradiation techniques of tomotherapy (TOMO) and volumetric-modulated arc therapy (VMAT) to investigate if novel conformal treatment methods could reduce the influence of contrast agent. In our study, patients with pancreatic cancer were enrolled to have 2 computed tomography (CT) scans in the same position without and with intravenous contrast agent for treatment planning. Then tumors and organ at risks were countered on contrast-enhanced CT (CECT) images. Each patient's CECT was assigned a TOMO plan and a VMAT plan. Then these plans were copied onto the non-CECT image and dose distribution was calculated with the same algorithm and structure sets. Finally, the dose distribution and the dose difference were analyzed for the target volume and organs at risk between the 2 sets of images. The statistic dosimetric result showed that for both TOMO and VMAT, no significant dose difference between CECT and non-CECT-based plan was observed. Dose difference was clinically negligible because the average relative percentage dose difference was 1% ± 1% for target volume, except a blurring effect at the higher dose region of the target volume. It implied that intravenous contrast agent will not affect dose calculation for pancreatic cancer radiotherapy significantly. Also the dose deviation based on TOMO showed no statistical difference compared with that on VMAT. For both superposition/conversation algorithm used by TOMO and Monte Carlo algorithm used by VMAT, the dosimetric difference was nonsignificant. A full analysis demonstrated a negligible dose difference of less than 1% between CECT-based plan and non-CECT-based plan. Therefore, contrast-enhanced CT image can be used directly for dose calculation of TOMO and VMAT plans for pancreatic cancer. It is unnecessary to scan twice then make a fusion of CECT and non-CECT, which would result to additional unnecessary radiation dose to patient and decrease work efficiency.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

The level of menadione redox-cycling in pancreatic β-cells is proportional to the glucose concentration: Role of NADH and consequences for insulin secretion

Pancreatic β-cells release insulin in response to elevation of glucose from basal (4–7 mM) to stimulatory (8–16 mM) levels. Metabolism of glucose by the β-cell results in the production of low levels of reactive oxygen intermediates (ROI), such as hydrogen peroxide (H{sub 2}O{sub 2}), a newly recognized coupling factor linking glucose metabolism to insulin secretion. However, high and toxic levels of H{sub 2}O{sub 2} inhibit insulin secretion. Menadione, which produces H{sub 2}O{sub 2} via redox cycling mechanism in a dose-dependent manner, was investigated for its effect on β-cell metabolism and insulin secretion in INS-1 832/13, a rat β-cell insulinoma cell line, and primary rodent islets. Menadione-dependent redox cycling and resulting H{sub 2}O{sub 2} production under stimulatory glucose exceeded several-fold those reached at basal glucose. This was paralleled by a differential effect of menadione (0.1–10 μM) on insulin secretion, which was enhanced at basal, but inhibited at stimulatory glucose. Redox cycling of menadione and H{sub 2}O{sub 2} formation was dependent on glycolytically-derived NADH, as inhibition of glycolysis and application of non-glycogenic insulin secretagogues did not support redox cycling. In addition, activity of plasma membrane electron transport, a system dependent in part on glycolytically-derived NADH, was also inhibited by menadione. Menadione-dependent redox cycling was sensitive to the NQO1 inhibitor dicoumarol and the flavoprotein inhibitor diphenylene iodonium, suggesting a role for NQO1 and other oxidoreductases in this process. These data may explain the apparent dichotomy between the stimulatory and inhibitory effects of H{sub 2}O{sub 2} and menadione on insulin secretion. -- Highlights: ► Menadione stimulation or inhibition of insulin secretion is dependent upon applied glucose levels. ► Menadione-dependent H{sub 2}O{sub 2} production is proportional to applied glucose levels. ► Quinone-mediated redox cycling is dependent on glycolysis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Eriocalyxin B induces apoptosis and cell cycle arrest in pancreatic adenocarcinoma cells through caspase- and p53-dependent pathways

Pancreatic cancer is difficult to detect early and responds poorly to chemotherapy. A breakthrough in the development of new therapeutic agents is urgently needed. Eriocalyxin B (EriB), isolated from the Isodon eriocalyx plant, is an ent-kaurane diterpenoid with promise as a broad-spectrum anti-cancer agent. The anti-leukemic activity of EriB, including the underlying mechanisms involved, has been particularly well documented. In this study, we demonstrated for the first time EriB's potent cytotoxicity against four pancreatic adenocarcinoma cell lines, namely PANC-1, SW1990, CAPAN-1, and CAPAN-2. The effects were comparable to that of the chemotherapeutic camptothecin (CAM), but with much lower toxicity against normal human liver WRL68 cells. EriB's cytoxicity against CAPAN-2 cells was found to involve caspase-dependent apoptosis and cell cycle arrest at the G2/M phase. Moreover, the p53 pathway was found to be activated by EriB in these cells. Furthermore, in vivo studies showed that EriB inhibited the growth of human pancreatic tumor xenografts in BALB/c nude mice without significant secondary adverse effects. These results suggest that EriB should be considered a candidate for pancreatic cancer treatment. -- Highlights: ► We study Eriocalyxin B (EriB)'s cytotoxic effects on pancreatic cancer cell lines. ► EriB inhibits cell proliferation via mediation of apoptosis and cell cycle arrest. ► The effects are involved in caspase-dependent apoptosis and p53 pathway. ► In vivo study also shows EriB inhibits the growth of human pancreatic tumor. ► EriB can be a good candidate for chemotherapy in pancreatic cancer.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

A peroxisome proliferator-activated receptor ligand MCC-555 imparts anti-proliferative response in pancreatic cancer cells by PPARgamma-independent up-regulation of KLF4

MCC-555 is a novel PPARα/γ dual ligand of the thiazolidinedione class and was recently developed as an anti-diabetic drug with unique properties. MCC-555 also has anti-proliferative activity through growth inhibition and apoptosis induction in several cancer cell types. Our group has shown that MCC-555 targets several proteins in colorectal tumorigenesis including nonsteroidal anti-inflammatory drug (NSAID)-activated gene (NAG-1) which plays an important role in chemoprevention responsible for chemopreventive compounds. NAG-1 is a member of the TGF-β superfamily and is involved in tumor progression and development; however, NAG-1's roles in pancreatic cancer have not been studied. In this report, we found that MCC-555 alters not only NAG-1 expression, but also p21 and cyclin D1 expression. NAG-1 and p21 expression was not blocked by PPARγ-specific antagonist GW9662, suggesting that MCC-555-induced NAG-1 and p21 expression is independent of PPARγ activation. However, decreasing cyclin D1 by MCC-555 seems to be affected by PPARγ activation. Further, we found that the GC box located in the NAG-1 promoter play an important role in NAG-1 transactivation by MCC-555. Subsequently, we screened several transcription factors that may bind to the GC box region in the NAG-1 promoter and found that KLF4 potentially binds to this region. Expression of KLF4 precedes NAG-1 and p21 expression in the presence of MCC-555, whereas blocking KLF4 expression using specific KLF4 siRNA showed that both NAG-1 and p21 expression by MCC-555 was blocked. In conclusion, MCC-555's actions on anti-proliferation involve both PPARγ-dependent and -independent pathways, thereby enhancing anti-tumorigenesis in pancreatic cancer cells. -- Highlights: ► PPARα/γ ligand MCC-555 exhibits anti-proliferative activity in pancreatic cancer cells. ► MCC-555 affects KLF4 expression following by NAG-1 and p21 expression in a PPARγ independent manner. ► MCC-555 also affects cyclin D1 down-regulation in a PPARγ dependent manner. ► To our knowledge, this is the first report that MCC-555 affects anti-proliferative activity in pancreatic cancer cells, along with multiple targets.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Oleic acid and glucose regulate glucagon-like peptide 1 receptor expression in a rat pancreatic ductal cell line

The glucagon-like peptide 1 receptor (GLP1R) plays a critical role in glucose metabolism and has become an important target for a growing class of drugs designed to treat type 2 diabetes. In vitro studies were designed to investigate the effect of the GLP1R agonist, exenatide (Ex4), in “on-target” RIN-5mF (islet) cells as well as in “off-target” AR42J (acinar) and DSL-6A/C1 (ductal) cells in a diabetic environment. Ex4 increased islet cell proliferation but did not affect acinar cells or ductal cells at relevant concentrations. A high caloric, high fat diet is a risk factor for impaired glucose tolerance and type-2 diabetes. An in vitro Oleic acid (OA) model was used to investigate the effect of Ex4 in a high calorie, high fat environment. At 0.1 and 0.4 mM, OA mildly decreased the proliferation of all pancreatic cell types. Ex4 did not potentiate the inhibitory effect of OA on cell proliferation. Akt phosphorylation in response to Ex4 was diminished in OA-treated ductal cells. GLP1R protein detected by western blot was time and concentration dependently decreased after glucose stimulation in OA-treated ductal cells. In ductal cells, OA treatment altered the intracellular localization of GLP1R and its co-localization with early endosome and recycling endosomes. Chloroquine (lysosomal inhibitor), N-acetyl-L-cysteine (reactive oxygen species scavenger) and wortmannin (a phosphatidylinositol-3-kinase inhibitor), fully or partially, rescued GLP1R protein in OA-pretreated, glucose-stimulated ductal cells. The impact of altered regulation on phenotype/function is presently unknown. However, these data suggest that GLP1R regulation in ductal cells can be altered by a high fat, high calorie environment. -- Highlights: ► Exenatide did not inhibit islet, acinar or ductal cell proliferation. ► GLP1R protein decreased after glucose stimulation in oleic acid-treated ductal cells. ► Oleic acid treatment altered localization of GLP1R with early and recycling endosomes.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

The effect of smoking cessation pharmacotherapies on pancreatic beta cell function

The goal of our study was to evaluate whether drugs currently used for smoking cessation (i.e., nicotine replacement therapy, varenicline [a partial agonist at nicotinic acetylcholine receptors (nAChR)] and bupropion [which acts in part as a nAChR antagonist]) can affect beta cell function and determine the mechanism(s) of this effect. INS-1E cells, a rat beta cell line, were treated with nicotine, varenicline and bupropion to determine their effects on beta cell function, mitochondrial electron transport chain enzyme activity and cellular/oxidative stress. Treatment of INS-1E cells with equimolar concentrations (1 μM) of three test compounds resulted in an ablation of normal glucose-stimulated insulin secretion by the cells. This disruption of normal beta cell function was associated with mitochondrial dysfunction since all three compounds tested significantly decreased the activity of mitochondrial electron transport chain enzyme activity. These results raise the possibility that the currently available smoking cessation pharmacotherapies may also have adverse effects on beta cell function and thus glycemic control in vivo. Therefore whether or not the use of nicotine replacement therapy, varenicline and bupropion can cause endocrine changes which are consistent with impaired pancreatic function warrants further investigation. -- Highlights: ► Smoking cessation drugs have the potential to disrupt beta cell function in vitro. ► The effects of nicotine, varenicline and bupropion are similar. ► The impaired beta cell function is mediated by mitochondrial dysfunction. ► If similar effects are seen in vivo, these drugs may increase the risk of diabetes.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Involvement of the Nrf2-proteasome pathway in the endoplasmic reticulum stress response in pancreatic β-cells

The ubiquitin-proteasome system plays a central role in protein quality control through endoplasmic reticulum (ER)-associated degradation (ERAD) of unfolded and misfolded proteins. NF-E2‐related factor 2 (Nrf2) is a transcription factor that controls the expression of an array of phase II detoxification and antioxidant genes. Nrf2 signaling has additionally been shown to upregulate the expression of the proteasome catalytic subunits in several cell types. Here, we investigated the role of Nrf2 in tunicamycin-induced ER stress using a murine insulinoma β-cell line, βTC-6. shRNA-mediated silencing of Nrf2 expression in βTC-6 cells significantly increased tunicamycin-induced cytotoxicity, elevated the expression of the pro-apoptotic ER stress marker Chop10, and inhibited tunicamycin-inducible expression of the proteasomal catalytic subunits Psmb5 and Psmb6. The effects of 3H-1,2-dithiole-3-thione (D3T), a small molecule Nrf2 activator, on ER stress were also examined in βTC-6 cells. D3T pretreatment reduced tunicamycin cytotoxicity and attenuated the tunicamycin-inducible Chop10 and protein kinase RNA-activated‐like ER kinase (Perk). The protective effect of D3T was shown to be associated with increased ERAD. D3T increased the expression of Psmb5 and Psmb6 and elevated chymotrypsin-like peptidase activity; proteasome inhibitor treatment blocked D3T effects on tunicamycin cytotoxicity and ER stress marker changes. Similarly, silencing of Nrf2 abolished the protective effect of D3T against ER stress. These results indicate that the Nrf2 pathway contributes to the ER stress response in pancreatic β-cells by enhancing proteasome-mediated ERAD. -- Highlights: ► Nrf2 silencing in pancreatic β-cells enhanced tunicamycin-mediated ER stress. ► Expression of the proteasome was inducible by Nrf2 signaling. ► Nrf2 activator D3T protected β-cells from tunicamycin-mediated ER stress. ► Protective effect of D3T was associated with Nrf2-dependent proteasome induction.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Deficiency in the nuclear factor E2-related factor 2 renders pancreatic β-cells vulnerable to arsenic-induced cell damage

Chronic human exposure to inorganic arsenic (iAs), a potent environmental oxidative stressor, is associated with increased prevalence of type 2 diabetes, where impairment of pancreatic β-cell function is a key pathogenic factor. Nuclear factor E2-related factor 2 (Nrf2) is a central transcription factor regulating cellular adaptive response to oxidative stress. However, persistent activation of Nrf2 in response to chronic oxidative stress, including inorganic arsenite (iAs{sup 3+}) exposure, blunts glucose-triggered reactive oxygen species (ROS) signaling and impairs glucose-stimulated insulin secretion (GSIS). In the current study, we found that MIN6 pancreatic β-cells with stable knockdown of Nrf2 (Nrf2-KD) by lentiviral shRNA and pancreatic islets isolated from Nrf2-knockout (Nrf2−/−) mice exhibited reduced expression of several antioxidant and detoxification enzymes in response to acute iAs{sup 3+} exposure. As a result, Nrf2-KD MIN6 cells and Nrf2−/− islets were more susceptible to iAs{sup 3+} and monomethylarsonous acid (MMA{sup 3+})-induced cell damage, as measured by decreased cell viability, augmented apoptosis and morphological change. Pretreatment of MIN6 cells with Nrf2 activator tert-butylhydroquinone protected the cells from iAs{sup 3+}-induced cell damage in an Nrf2-dependent fashion. In contrast, antioxidant N‐acetyl cysteine protected Nrf2-KD MIN6 cells against acute cytotoxicity of iAs{sup 3+}. The present study demonstrates that Nrf2-mediated antioxidant response is critical in the pancreatic β-cell defense mechanism against acute cytotoxicity by arsenic. The findings here, combined with our previous results on the inhibitory effect of antioxidants on ROS signaling and GSIS, suggest that Nrf2 plays paradoxical roles in pancreatic β-cell dysfunction induced by environmental arsenic exposure. -- Highlights: ► Lack of Nrf2 reduced expression of antioxidant genes induced by iAs{sup 3+} in β-cells. ► Deficiency of Nrf2 in β-cells sensitized to iAs{sup 3+} and MMA{sup 3+}-induced cytotoxicity. ► Nrf2 activation protected β-cells from acute iAs{sup 3+} cytotoxicity.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

Methylated trivalent arsenicals are potent inhibitors of glucose stimulated insulin secretion by murine pancreatic islets

Epidemiologic evidence has linked chronic exposure to inorganic arsenic (iAs) with an increased prevalence of diabetes mellitus. Laboratory studies have identified several mechanisms by which iAs can impair glucose homeostasis. We have previously shown that micromolar concentrations of arsenite (iAs{sup III}) or its methylated trivalent metabolites, methylarsonite (MAs{sup III}) and dimethylarsinite (DMAs{sup III}), inhibit the insulin-activated signal transduction pathway, resulting in insulin resistance in adipocytes. Our present study examined effects of the trivalent arsenicals on insulin secretion by intact pancreatic islets isolated from C57BL/6 mice. We found that 48-hour exposures to low subtoxic concentrations of iAs{sup III}, MAs{sup III} or DMAs{sup III} inhibited glucose-stimulated insulin secretion (GSIS), but not basal insulin secretion. MAs{sup III} and DMAs{sup III} were more potent than iAs{sup III} as GSIS inhibitors with estimated IC{sub 50} ≤ 0.1 μM. The exposures had little or no effects on insulin content of the islets or on insulin expression, suggesting that trivalent arsenicals interfere with mechanisms regulating packaging of the insulin transport vesicles or with translocation of these vesicles to the plasma membrane. Notably, the inhibition of GSIS by iAs{sup III}, MAs{sup III} or DMAs{sup III} could be reversed by a 24-hour incubation of the islets in arsenic-free medium. These results suggest that the insulin producing pancreatic β-cells are among the targets for iAs exposure and that the inhibition of GSIS by low concentrations of the methylated metabolites of iAs may be the key mechanism of iAs-induced diabetes. - Highlights: ► Trivalent arsenicals inhibit glucose stimulated insulin secretion by pancreatic islets. ► MAs{sup III} and DMAs{sup III} are more potent inhibitors than arsenite with IC{sub 50} ∼ 0.1 μM. ► The arsenicals have little or no effects on insulin expression in pancreatic islets. ► The inhibition of insulin secretion by arsenite, MAs{sup III} or DMAs{sup III} is reversible. ► Thus, pancreatic β-cells may be primary targets for chronic exposure to arsenic.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

A binuclear complex constituted by diethyldithiocarbamate and copper(I) functions as a proteasome activity inhibitor in pancreatic cancer cultures and xenografts

It is a therapeutic strategy for cancers including pancreatic to inhibit proteasome activity. Disulfiram (DSF) may bind copper (Cu) to form a DSF–Cu complex. DSF–Cu is capable of inducing apoptosis in cancer cells by inhibiting proteasome activity. DSF is rapidly converted to diethyldithiocarbamate (DDTC) within bodies. Copper(II) absorbed by bodies is reduced to copper(I) when it enters cells. We found that DDTC and copper(I) could form a binuclear complex which might be entitled DDTC–Cu(I), and it had been synthesized by us in the laboratory. This study is to investigate the anticancer potential of this complex on pancreatic cancer and the possible mechanism. Pancreatic cancer cell lines, SW1990, PANC-1 and BXPC-3 were used for in vitro assays. Female athymic nude mice grown SW1990 xenografts were used as animal models. Cell counting kit-8 (cck-8) assay and flow cytometry were used for analyzing apoptosis in cells. A 20S proteasome assay kit was used in proteasome activity analysis. Western blot (WB) and immunohistochemistry (IHC) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays were used in tumor sample analysis. The results suggest that DDTC–Cu(I) inhibit pancreatic cancer cell proliferation and proteasome activity in vitro and in vivo. Accumulation of ubiquitinated proteins, and increased p27 as well as decreased NF-κB expression were detected in tumor tissues of DDTC–Cu(I)-treated group. Our data indicates that DDTC–Cu(I) is an effective proteasome activity inhibitor with the potential to be explored as a drug for pancreatic cancer. - Highlights: • A new structure of DDTC–Cu(I) was reported for the first time. • DDTC–Cu(I) dissolved directly in water was for in vitro and in vivo uses. • DDTC–Cu(I) demonstrated significant anticancer effect in vitro and in vivo. • DDTC–Cu(I) is capable of inhibiting proteasome activity in vitro and in vivo.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

N-methylhemeanthidine chloride, a novel Amaryllidaceae alkaloid, inhibits pancreatic cancer cell proliferation via down-regulating AKT activation

We previously reported the isolation of a novel Amaryllidaceae alkaloid, N-methylhemeanthidine chloride (NMHC), from Zephyranthes candida, which exhibits potent cytotoxicity in a spectrum of tumor cells. However, the mechanism of action remains unclear. Using multiple cell lines derived from human pancreatic cancer, one of the most mortal and refractory human malignancies, we further studied the NMHC-mediated cytotoxicity and found that it induced drastic cytotoxicity in pancreatic cancer cells whereas an insignificant effect on a noncancerous cell line. The NMHC-mediated growth inhibition was more severe than the first-line chemotherapeutic agent gemcitabine, leading to cell cycle arrest, apoptotic death and decreased glycolysis. NMHC exerted its function through down-regulating AKT activation, and the ectopic expression of activated AKT rescued the growth inhibition. Consistently, NMHC injections in a pancreatic cancer xenograft model manifested the anti-tumor effect in vivo. Engrafted tumor cells underwent AKT attenuation and apoptotic death upon treatments. As such, we here demonstrate the AKT inhibition may be one of the mechanisms by which NMHC decreases tumor cell survival rate in vitro and in vivo. Our data thereby suggest that NMHC holds great promise as a potent chemotherapeutic agent against pancreatic cancer and sheds new light on obtaining such agents from natural products toward therapeutic purposes. - Highlights: • N-methylhemeanthidine chloride (NMHC) is a novel Amaryllidaceae alkaloid. • NMHC exhibits potent anti-neoplastic activity. • NMHC leads to cell cycle arrest, apoptotic death and decreased metabolism. • NMHC down-regulates the AKT signaling pathway.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Dimethyl sulfoxide inhibits spontaneous diabetes and autoimmune recurrence in non-obese diabetic mice by inducing differentiation of regulatory T cells

Type 1 diabetes mellitus (T1D) is caused by the destruction of insulin-producing β cells in pancreatic islets by autoimmune T cells. Islet transplantation has been established as an effective therapeutic strategy for T1D. However, the survival of islet grafts can be disrupted by recurrent autoimmunity. Dimethyl sulfoxide (DMSO) is a solvent for organic and inorganic substances and an organ-conserving agent used in solid organ transplantations. DMSO also exerts anti-inflammatory, reactive oxygen species scavenger and immunomodulatory effects and therefore exhibits therapeutic potential for the treatment of several human inflammatory diseases. In this study, we investigated the therapeutic potential of DMSO in the inhibition of autoimmunity. We treated an animal model of islet transplantation (NOD mice) with DMSO. The survival of the syngeneic islet grafts was significantly prolonged. The population numbers of CD8, DC and Th1 cells were decreased, and regulatory T (Treg) cell numbers were increased in recipients. The expression levels of IFN-γ and proliferation of T cells were also reduced following DMSO treatment. Furthermore, the differentiation of Treg cells from naive CD4 T cells was significantly increased in the in vitro study. Our results demonstrate for the first time that in vivo DMSO treatment suppresses spontaneous diabetes and autoimmune recurrence in NOD mice by inhibiting the Th1 immune response and inducing the differentiation of Treg cells. - Highlights: • We report a therapeutic potential of DMSO in autoimmune diabetes. • DMSO exhibits an immune modulatory effect. • DMSO treatment increases regulatory T cell differentiation. • The increase in STAT5 signaling pathway explains the effect of DMSO in Tregs.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Molybdenum induces pancreatic β-cell dysfunction and apoptosis via interdependent of JNK and AMPK activation-regulated mitochondria-dependent and ER stress-triggered pathways

Molybdenum (Mo), a well-known toxic environmental and industrial pollutant, causes adverse health effects and diseases in humans and has received attention as a potential risk factor for DM. However, the roles of Mo in the mechanisms of the toxicological effects in pancreatic β-cells are mostly unclear. In this study, the results revealed dysfunction of insulin secretion and apoptosis in the pancreatic β-cell-derived RIN-m5F cells and the isolated mouse islets in response to Mo. These effects were accompanied by a mitochondria-dependent apoptotic signals including a decreased in the MMP, an increase in cytochrome c release, and the activation of caspase cascades and PARP. In addition, ER stress was triggered as indicated by several key molecules of the UPR. Furthermore, exposure to Mo induced the activation of ERK1/2, JNK, AMPKα, and GSK3-α/β. Pretreatment with specific pharmacological inhibitors (in RIN-m5F cells and isolated mouse islets) of JNK (SP600125) and AMPK (Compound C) or transfection with si-RNAs (in RIN-m5F cells) specific to JNK and AMPKα effectively prevented the Mo-induced apoptosis and related signals, but inhibitors of ERK1/2 and GSK3-α/β (PD98059 and LiCl, respectively) did not reverse the Mo-induced effects. Additionally, both the inhibitors and specific si-RNAs could suppress the Mo-induced phosphorylation of JNK and AMPKα each other. Taken together, these results suggest that Mo exerts its cytotoxicity on pancreatic β-cells by inducing dysfunction and apoptosis via interdependent JNK and AMPK activation downstream-regulated mitochondrial-dependent and ER stress-triggered apoptosis pathways. - Highlights: • Molybdenum (Mo) induces pancreatic β-cell dysfunction and apoptosis. • Mo causes β-cell death via mitochondria-dependent caspase cascades signals. • ER stress-triggered apoptotic pathway also regulates Mo-induced β-cell death. • Interdependent of JNK and AMPK activation involves in Mo-induced β-cell apoptosis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Systemic metabolic derangement, pulmonary effects, and insulin insufficiency following subchronic ozone exposure in rats

Acute ozone exposure induces a classical stress response with elevated circulating stress hormones along with changes in glucose, protein and lipid metabolism in rats, with similar alterations in ozone-exposed humans. These stress-mediated changes over time have been linked to insulin resistance. We hypothesized that acute ozone-induced stress response and metabolic impairment would persist during subchronic episodic exposure and induce peripheral insulin resistance. Male Wistar Kyoto rats were exposed to air or 0.25 ppm or 1.00 ppm ozone, 5 h/day, 3 consecutive days/week (wk) for 13 wks. Pulmonary, metabolic, insulin signaling and stress endpoints were determined immediately after 13 wk or following a 1 wk recovery period (13 wk + 1 wk recovery). We show that episodic ozone exposure is associated with persistent pulmonary injury and inflammation, fasting hyperglycemia, glucose intolerance, as well as, elevated circulating adrenaline and cholesterol when measured at 13 wk, however, these responses were largely reversible following a 1 wk recovery. Moreover, the increases noted acutely after ozone exposure in non-esterified fatty acids and branched chain amino acid levels were not apparent following a subchronic exposure. Neither peripheral or tissue specific insulin resistance nor increased hepatic gluconeogenesis were present after subchronic ozone exposure. Instead, long-term ozone exposure lowered circulating insulin and severely impaired glucose-stimulated beta-cell insulin secretion. Thus, our findings in young-adult rats provide potential insights into epidemiological studies that show a positive association between ozone exposures and type 1 diabetes. Ozone-induced beta-cell dysfunction may secondarily contribute to other tissue-specific metabolic alterations following chronic exposure due to impaired regulation of glucose, lipid, and protein metabolism. - Highlights: • Subchronic episodic ozone exposure caused pulmonary and metabolic effects. • These effects were largely reversible upon one week recovery. • Ozone exposure did not cause liver or muscle insulin resistance. • Subchronic ozone exposure led to decrease in serum insulin. • Ozone severely impaired beta cell insulin secretion in response to glucose.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Identification of gene expression profiling associated with erlotinib-related skin toxicity in pancreatic adenocarcinoma patients

Erlotinib is an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that showed activity against pancreatic ductal adenocarcinoma (PDAC). The drug's most frequently reported side effect as a result of EGFR inhibition is skin rash (SR), a symptom which has been associated with a better therapeutic response to the drug. Gene expression profiling can be used as a tool to predict which patients will develop this important cutaneous manifestation. The aim of the present study was to identify which genes may influence the appearance of SR in PDAC patients. The study included 34 PDAC patients treated with erlotinib: 21 patients developed any grade of SR, while 13 patients did not (controls). Before administering any chemotherapy regimen and the development of SR, we collected RNA from peripheral blood samples of all patients and studied the differential gene expression pattern using the Illumina microarray platform HumanHT-12 v4 Expression BeadChip. Seven genes (FAM46C, IFITM3, GMPR, DENND6B, SELENBP1, NOL10, and SIAH2), involved in different pathways including regulatory, migratory, and signalling processes, were downregulated in PDAC patients with SR. Our results suggest the existence of a gene expression profiling significantly correlated with erlotinib-induced SR in PDAC that could be used as prognostic indicator in this patients. - Highlights: • Skin rash (SR) is the most characteristic side effect of erlotinib in PDAC patients. • Erlotinib-induced SR has been associated with a better clinical outcome. • Gene expression profiling was used to determine who will develop this manifestation. • 7 genes involved in different pathways were downregulated in PDAC patients with SR. • Our profile correlated with erlotinib-induced SR in PDAC could be used for prognosis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

EX4 stabilizes and activates Nrf2 via PKCδ, contributing to the prevention of oxidative stress-induced pancreatic beta cell damage

Oxidative stress in pancreatic beta cells can inhibit insulin secretion and promote apoptotic cell death. Exendin-4 (EX4), a glucagon-like peptide-1 receptor agonist, can suppress beta cell apoptosis, improve beta cell function and protect against oxidative damage. In this study, we investigated the molecular mechanisms for antioxidative effects of EX4 in pancreatic beta cells. INS-1 cells, a rat insulinoma cell line, were pretreated with EX4 and exposed to palmitate or H{sub 2}O{sub 2}. Reactive oxygen species (ROS) production, and glutathione and insulin secretion were measured. The mRNA and protein expression levels of antioxidant genes were examined. The level of nuclear factor erythroid 2-related factor 2 (Nrf2), its binding to antioxidant response element (ARE), and its ubiquination in the presence of EX4 were determined. The Nrf2 signaling pathway was determined using rottlerin (protein kinase [PK]Cδ inhibitor), H89 (PKA inhibitor) and LY294002 (phosphatidylinositide 3-kinase [PI3K] inhibitor). EX4 treatment decreased ROS production, recovered cellular glutathione levels and insulin secretion in the presence of oxidative stress in INS-1 cells. The expression levels of glutamate-cysteine ligase catalytic subunit and heme oxygenase-1 were increased by EX4 treatment. EX4 promoted Nrf2 translocation, ARE binding activity and enhanced stabilization of Nrf2 by inhibition of ubiquitination. Knockdown of Nrf2 abolished the effect of EX4 on increased insulin secretion. Inhibition of PKCδ attenuated Nrf2 translocation and antioxidative gene expression by EX4 treatment. We suggest that EX4 activates and stabilizes Nrf2 through PKCδ activation, contributing to the increase of antioxidant gene expression and consequently improving beta cell function in the presence of oxidative stress. - Highlights: • EX4 protects against oxidative stress-induced pancreatic beta cell dysfunction. • EX4 increases antioxidant gene expression. • Antioxidative effect of EX4 is mediated by Nrf2. • EX4 increases Nrf2 level by stabilizing Nrf2 protein. • EX4 stabilizes Nrf2 by activation of PKCδ.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Emodin suppresses TGF-β1-induced epithelial-mesenchymal transition in alveolar epithelial cells through Notch signaling pathway

Pulmonary fibrosis is characterized by the destruction of lung tissue architecture and the formation of fibrous foci, currently has no satisfactory treatment. Emodin is a component of Chinese herb that has been reported to be medicament on pancreatic fibrosis and liver fibrosis. However, its role in pulmonary fibrosis has not been established yet. In the present study, we investigated the hypothesis that Emodin plays an inhibitory role in TGF-β1 induced epithelial-mesenchymal transition (EMT) of alveolar epithelial cell, and Emodin exerts its effect through the Notch signaling pathway. Emodin inhibits the proliferation of Rat alveolar type II epithelial cells RLE-6TN in a concentration-dependent manner; reduces the expression of Collagen I, α-SMA and Vimentin, promotes the expression of E-cadherin. Moreover, Emodin could regulate the expression patterns of the Notch signaling pathway-related factors and reduce the Notch-1 nucleus translocation. Knockdown of Notch-1 enhances the inhibitory effect of Emodin on TGF-β1-induced EMT in RLE-6TN cells. In conclusion, the data of the present study suggests that Emodin suppresses TGF-β1-induced EMT in alveolar epithelial cells through Notch signaling pathway and shows the potential to be effective in the treatment of pulmonary fibrosis. - Highlights: • Emodin inhibits TGF-β1-induced EMT in alveolar epithelial cells. • Emodin regulates the expression patterns of the Notch signaling pathway-related factors. • Emodin inhibits TGF-β1-induced Notch-1 nucleus translocation and activation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Stem cells as the root of pancreatic ductal adenocarcinoma

Emerging evidence suggests that stem cells play a crucial role not only in the generation and maintenance of different tissues, but also in the development and progression of malignancies. For the many solid cancers, it has now been shown that they harbor a distinct subpopulation of cancer cells that bear stem cell features and therefore, these cells are termed cancer stem cells (CSC) or tumor-propagating cells. CSC are exclusively tumorigenic and essential drivers for tumor progression and metastasis. Moreover, it has been shown that pancreatic ductal adenocarcinoma does not only contain one homogeneous population of CSC rather than diverse subpopulations that may have evolved during tumor progression. One of these populations is called migrating CSC and can be characterized by CXCR4 co-expression. Only these cells are capable of evading the primary tumor and traveling to distant sites such as the liver as the preferred site of metastatic spread. Clinically even more important, however, is the observation that CSC are highly resistant to chemo- and radiotherapy resulting in their relative enrichment during treatment and rapid relapse of disease. Many laboratories are now working on the further in-depth characterization of these cells, which may eventually allow for the identification of their Achilles heal and lead to novel treatment modalities for fighting this deadly disease.

60 APPLIED LIFE SCIENCES↗