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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 739 records · Page 41
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

MicroRNA-139-5p acts as a tumor suppressor by targeting ELTD1 and regulating cell cycle in glioblastoma multiforme

MicroRNA-139-5p was identified to be significantly down-regulated in glioblastoma multiform (GBM) by miRNA array. In this report we aimed to clarify its biological function, molecular mechanisms and direct target gene in GBM. Twelve patients with GBM were analyzed for the expression of miR-139-5p by quantitative RT-PCR. miR-139-5p overexpression was established by transfecting miR-139-5p-mimic into U87MG and T98G cells, and its effects on cell proliferation were studied using MTT assay and colony formation assays. We concluded that ectopic expression of miR-139-5p in GBM cell lines significantly suppressed cell proliferation and inducing apoptosis. Bioinformatics coupled with luciferase and western blot assays also revealed that miR-139-5p suppresses glioma cell proliferation by targeting ELTD1 and regulating cell cycle. - Highlights: • miR-139-5p is downregulated in GBM. • miR-139-5p regulates cell proliferation through inducing apoptosis. • miR-139-5p regulates glioblastoma tumorigenesis by targeting 3′UTR of ELTD1. • miR-139-5p is involved in cell cycle regulation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

miR-4458 suppresses glycolysis and lactate production by directly targeting hexokinase2 in colon cancer cells

miR-4458, a new tumor-suppressor, was reported to down-regulated in human hepatocellular carcinoma. The expression status, roles and inhibitory mechanisms of miR-4458 in other tumors still need to be clarified. The aim of this study is to investigate the effects of miR-4458 and to elucidate the potential mechanism in colon cancer cells. Using bioinformatic databases, we predicted that hexokinase2 (HK2), a rate-limiting enzyme in the glycolytic pathway, was a target of miR-4458, so the effects of miR-4458 on glycolysis and lactate production was assessed in colon cancer cells. We found that miR-4458 was down-regulated and HK2 was up-regulated in colon cancer cells. Overexpression of miR-4458 inhibited proliferation, glycolysis, and lactate production under both normoxic and hypoxic conditions. Luciferase activity assays showed that HK2 was a direct target of miR-4458. Moreover, knockdown of HK2 by specific RNAi also suppressed proliferation, glycolysis, and lactate production under both normoxic and hypoxic conditions. In conclusion, our findings suggested that miR-4458 inhibited the progression of colon cancer cells by inhibition of glycolysis and lactate production via directly targeting HK2 mRNA. - Highlights: • miR-4458 is down-regulated in colon cancer cells. • miR-4458 suppresses proliferation, glycolysis, and lactate production. • HK2 is a target of miR-4458. • HK2 knockdown inhibits proliferation, glycolysis, and lactate production.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Expression of hypoxia-inducible factor-1 by trophectoderm cells in response to hypoxia and epidermal growth factor

The low oxygen environment in the uterine environment requires pre-implantation embryos to adapt to oxygen deficiency. Hypoxia-inducible factor (HIF)-1 is a master regulator whereby cells adapt to changes in oxygen concentrations. In addition to hypoxic conditions, non-hypoxic stimuli such as growth factors also activate expression of HIF-1. In this study, the mechanisms underlying low oxygen-dependent and epidermal growth factor (EGF)-dependent expression of HIF-1α were explored using porcine trophectoderm (pTr) cells. The results indicated that expression of HIF-1α and HIF-1β mRNAs was not affected by low concentrations of oxygen; however, hypoxic conditions markedly increased the abundance of HIF-1α protein, especially in nuclei of pTr cells. Even under normoxic conditions, the abundance of HIF-1α protein increased in response to EGF. This EGF-mediated increase in HIF-1α protein was blocked through inhibition of translation by cycloheximide. The inhibitors LY294002 (PI3K-AKT inhibitor), U0126 (inhibitor of ERK1/2) and rapamycin (mTOR inhibitor) also blocked the ability of EGF to increase HIF-1α protein and to phosphorylate AKT, ERK1/2 and mTOR proteins. Both hypoxia and EGF induced proliferation of pTr cells. This ability of EGF to stimulate proliferation of pTr cells was suppressed by EGFR siRNA, but not HIF-1α siRNA, but a significant decrease in EGF-induced HIF-1α protein occurred when pTr cells were transfected with HIF-1α siRNA. The results of the present study suggest that pTr cells adapt to oxygen deficiency and proliferate in response to an oxygen-dependent HIF-1 system, and that EGF at maternal–conceptus interface can increase the abundance of HIF-1α protein via translational regulation through AKT, ERK1/2 and mTOR signaling cascades. - Highlights: • HIF-1α expression is up-regulated in pTr cells under low oxygen concentrations. • EGF induces HIF-1α accumulation in pTr cells. • EGF-induced HIF-1α accumulation is blocked by de-novo translation inhibitor. • EGF-induced HIF-1α accumulation is mediated by AKT, ERK1/2 and mTOR pathways. • Oxygen deficiency and EGF has stimulatory effect on proliferation of pTr cells.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

17β-estradiol exerts anticancer effects in anoikis-resistant hepatocellular carcinoma cell lines by targeting IL-6/STAT3 signaling

17β-Estradiol (E2) has been proven to exert protective effects against HCC; however, its mechanism on HCC proliferation and suppression of invasion remains to be further explored. Because HCC up-regulates serum Interleukin-6 (IL-6) levels and Signal Transducer and Activator of Transcription 3 (STAT3), molecular agents that attenuate IL-6/STAT3 signaling can potentially suppress HCC development. In this study, we examined involvement of E2 in anoikis resistance that induces invasion capacities and chemo-resistance. Huh-BAT and HepG2 cells grown under anchorage-independent condition were selected. The anoikis-resistant (AR) cells showed stronger chemo-resistance against sorafenib, doxorubicin, 5-fluorouracil and cisplatin compared to adherent HCC cells. AR HCC cells exhibited decreased expression of E-cadherin and increased expression of the N-cadherin and vimentin compared to adherent HCC cells. We then demonstrated that E2 suppressed cell proliferation in AR HCC cells. IL-6 treatment enhanced invasive characteristics, and E2 reversed it. Regarding mechanism of E2, it decreased in the phosphorylation of STAT3 that overexpressed on AR HCC cells. The inhibitory effect of E2 on cell growth was accompanied with cell cycle arrest at G2/M phase and caspase-3/9/PARP activation through c-Jun N-terminal Kinase (JNK) phosphorylation. Taken together, these findings suggested that E2 inhibited the proliferation of AR HCC cells through down-regulation of IL-6/STAT3 signaling. Thus, E2 can be a potential therapeutic drug for treatment of metastatic or chemo-resistant HCC. -- Highlights: •Anoikis-resistant HCC cells characterized chemo-resistant and metastatic potentials. •17β-Estradiol down-regulated IL-6/STAT3 signaling in anoikis-resistant HCC cells. •17β-Estradiol suppressed cell proliferation by inducing G2/M phase arrest and apoptosis though JNK phosphorylation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

High expression of hexokinase domain containing 1 is associated with poor prognosis and aggressive phenotype in hepatocarcinoma

Rapid progress and metastasis remain the major treatment failure modes of hepatocarcinoma (HCC). Unfortunately, the underlying molecular mechanisms of hepatoma cell proliferation and migration are poorly understood. Metabolic abnormalities play critical roles in tumorigenesis and progression. Hexokinase domain containing 1 (HKDC1) catalyzes the phosphorylation of glucose. However, the functions and mechanisms of HKDC1 in cancer remain unknown. In this study, real-time RT-PCR and Western blotting assays were used to detect the HKDC1 expression levels in HCC tissues and cell lines. The Oncomine™ Cancer Microarray Database was applied to analysis the correlations between HKDC1 expression and HCC clinical characteristics. MTT and Transwell migration assays were performed to determine the functions of HKDC1 in HCC cells. The effect of HKDC1 on Wnt/β-catenin signaling pathway was assessed using Western blotting assay. In this study, we found that HKDC1 expression levels were elevated in HCC tissues compared with the adjacent tissues. HCC patients with high expression levels of HKDC1 had poor overall survival (OS). Furthermore, higher HKDC1 levels also predicted a worse OS of patients within solitary, elevated pre-operated serum alpha fetoprotein (AFP) level and higher tumor diameter. Moreover, silencing HKDC1 suppressed HCC cells proliferation and migration in vitro. Downregulated HKDC1 expression repressed β-Catenin and c-Myc expression, which indicates that silencing HKDC1 may reduce proliferation and migration via inhibiting the Wnt/β-catenin signaling pathway in HCC. In summary, HKDC1 provides further insight into HCC tumor progression and may provide a novel prognostic biomarker and therapeutic target for HCC treatment. -- Highlights: •HKDC1 is upregulated in HCC. •Patients with high HKDC1 expressions perform worse OS. •Silencing HKDC1 suppresses proliferation and migration. •Silencing HKDC1 represses Wnt/β-catenin signaling pathway.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

CTRP6 inhibits fibrogenesis in TGF-β1-stimulated human dermal fibroblasts

Skin fibrosis is characterized by excessive proliferation of fibroblasts and overproduction of extracellular matrix (ECM). C1q/tumor necrosis factor-related protein 6 (CTRP6), a member of CTRPs, has been involved in the development of cardiac fibrosis. However, the function and detailed regulatory mechanism of CTRP6 in skin fibrosis remain unclear. The aim of this study was to investigate the effect of CTRP6 on the activation of human dermal fibroblasts. Our results showed that CTRP6 was lowly expressed in scar tissues and transforming growth factor-β1 (TGF-β1)-treated dermal fibroblasts. CTRP6 overexpression significantly inhibited the proliferation of dermal fibroblasts, as well as suppressed the expression of ECM in TGF-β1-treated dermal fibroblasts. Furthermore, CTRP6 overexpression markedly inhibited TGF-β1-induced phosphorylation of Smad3 in dermal fibroblasts. In conclusion, the data reported here demonstrate that CTRP6 is able to inhibit the proliferation and ECM expression in human dermal fibroblasts through suppressing the TGF-β1/Smad3 signaling pathway. These findings suggest that CTRP6 may be a potential therapeutic target for the prevention of skin fibrosis. -- Highlights: •CTRP6 expression was decreased in scar tissues and TGF-β1-treated dermal fibroblasts. •CTRP6 inhibits TGF-β1-induced the proliferation of dermal fibroblasts. •CTRP6 inhibits expression of collagen type I and α-SMA. •CTRP6 inhibits the activation of TGF-β1/Smad3 signaling pathway in dermal fibroblasts.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Constitutive androstane receptor activation evokes the expression of glycolytic genes

It is well-known that constitutive androstane receptor (CAR) activation by 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP) increases the liver-to-body weight ratio. CAR-mediated liver growth is correlated with increased expression of the pleiotropic transcription factor cMyc, which stimulates cell cycle regulatory genes and drives proliferating cells into S phase. Because glycolysis supports cell proliferation and cMyc is essential for the activation of glycolytic genes, we hypothesized that CAR-mediated up-regulation of cMyc in mouse livers might play a role in inducing the expression of glycolytic genes. The aim of the present study was to examine the effect of long-term CAR activation on glycolytic genes in a mouse model not subjected to metabolic stress. We demonstrated that long-term CAR activation by TCPOBOP increases expression of cMyc, which was correlated with reduced expression of gluconeogenic genes and up-regulation of glucose transporter, glycolytic and mitochondrial pyruvate metabolising genes. These changes in gene expression after TCPOBOP treatment were strongly correlated with changes in levels of glycolytic intermediates in mouse livers. Moreover, we demonstrated a significant positive regulatory effect of TCPOBOP-activated CAR on both mRNA and protein levels of Pkm2, a master regulator of glucose metabolism and cell proliferation. Thus, our findings provide evidence to support the conclusion that CAR activation initiates a transcriptional program that facilitates the coordinated metabolic activities required for cell proliferation. - Highlights: • CAR-mediated liver growth is correlated with increased expression of cMyc. • CAR activation increased the expression of glycolytic genes in mouse livers. • CAR activation increased the level of Pkm2 in mouse livers.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Plexin A1 signaling confers malignant phenotypes in lung cancer cells

Aberrant changes to several signaling pathways because of genetic mutations or increased cytokine production are critical for tumor cells to become malignant. Semaphorin 3A (SEMA3A) acts as a bivalent factor that suppresses or promotes tumor development in different pathological backgrounds. Previously, we showed that SEMA3A positively regulated the proliferative and glycolytic activities of mouse-derived Lewis lung carcinoma (LLC) cells. Plexins A1-A4 (PLXNA1-PLXNA4) are SEMA3A receptors; however, it is not known which subtype is critical for oncogenic SEMA3A signaling. We used LLC cells to investigate the role of PLXNA1 in oncogenic SEMA3A signaling. Using short hairpin RNA-mediated knockdown, we investigated the effects of constitutive inhibition of Plxna1 on cell proliferation, metabolic dependency, and epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) sensitivity. We found that Plxna1 knockdown did not affect apoptosis but resulted in decreased cell proliferation and reductions in mRNA expression levels of proliferation-marker genes, such as Ccnd1, Pcna, and Myc. In addition, we found decreased mRNA expression levels of glycolysis-associated genes, such as Pkm2 and Ldha, and decreased lactate production. In contrast, we found no changes in the mRNA expression levels of oxidative phosphorylation-associated genes, such as Cycs, Cox5a, and Atp5g1. We found that Plxna1 knockdown conferred resistance to glucose starvation but increased cytotoxicity to oligomycin. Plxna1 or Sema3a knockdown caused an increased sensitivity to the EGFR-TKIs gefitinib and erlotinib, in Lewis lung carcinoma (LLC) cells. These findings demonstrate that PLXNA1 mediates the acquisition of malignant phenotypes induced by autocrine SEMA3A signaling. - Highlights: • Plxna1 knockdown decreased proliferation of Lewis lung carcinoma cells (LLCs). • Plxna1 knockdown decreased glycolytic activity in LLCs. • Plxna1 knockdown sensitized cells to inhibition of oxidative phosphorylation. • Plxna1 knockdown sensitized cells to EGFR-tyrosine kinase inhibitor.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

AMPK activation by GSK621 inhibits human melanoma cells in vitro and in vivo

Recent studies suggest that forced activation of AMP-activated protein kinase (AMPK) could inhibit melanoma cell proliferation. In this report, we evaluated the anti-melanoma cell activity by a novel small-molecular AMPK activator, GSK621. Treatment of GSK621 decreased survival and proliferation of human melanoma cells (A375, WM-115 and SK-Mel-2 lines), which was accompanied by activation of caspase-3/-9 and apoptosis. Reversely, caspase inhibitors attenuated GSK621-induced cytotoxicity against melanoma cells. Significantly, GSK621 was more potent than other AMPK activators (A769662, Compound 13 and AICAR) in inhibiting melanoma cells. Intriguingly, same GSK621 treatment was non-cytotoxic or pro-apoptotic against human melanocytes. Molecularly, we showed that activation of AMPK mediated GSK621's activity against melanoma cells. AMPKα1 shRNA knockdown or dominant negative mutation (T172A) dramatically attenuated GSK621-induced melanoma cell lethality. Further studies revealed that MEK-ERK activation might be the primary resistance factor of GSK621. MEK-ERK inhibition, either genetically or pharmacologically, significantly sensitized melanoma cells to GSK-621. Remarkably, intraperitoneal (i.p.) injection of GSK621 inhibited A375 tumor growth in SCID mice. Co-administration of MEK-ERK inhibitor MEK162 further sensitized GSK621-induced anti-A375 tumor activity in vivo. Together, the results imply that targeted activation of AMPK by GSK621 inhibits melanoma cell survival and proliferation. MEK-ERK inhibition may further sensitize GSK621's anti-melanoma cell activity in vitro and in vivo. - Highlights: • The novel AMPK activator GSK621 inhibits melanoma cell survival and proliferation. • GSK621 provokes caspase-dependent apoptotic death in melanoma cells. • GSK621 is more efficient other AMPK activators in inhibiting melanoma cells. • AMPKα silence or mutation attenuates GSK621's cytotoxicity in melanoma cells. • MEK-ERK inhibition sensitizes GSK621's anti-melanoma cell activity in vitro and in vivo.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Selenomethionine promoted hippocampal neurogenesis via the PI3K-Akt-GSK3β-Wnt pathway in a mouse model of Alzheimer's disease

The maintenance of neural system integrity and function is the ultimate goal for the treatment of neurodegenerative disease such as Alzheimer's disease (AD). Neurogenesis plays an integral role in the maintenance of neural and cognitive functions, and its dysfunction is regarded as a major cause of cognitive impairment in AD. Moreover, the induction of neurogenesis by targeting endogenous neural stem cells (NSCs) is considered as one of the most promising treatment strategies. Our previous studies demonstrated that selenomethionine (Se-Met) was able to reduce β-amyloid peptide (Aβ) deposition, decrease Tau protein hyperphosphorylation and markedly improve cognitive functions in triple transgenic (3xTg) AD mice. In this study, we reported that the therapeutic effect of Se-Met on AD could also be due to neurogenesis modulation. By using the cultured hippocampal NSCs from 3xTg AD mice, we discovered that Se-Met (1–10 μM) with low concentration could promote NSC proliferation, while the one with a high concentration (50,100 μM) inhibiting proliferation. In subsequent studies, we also found that Se-Met activated the signaling pathway of PI3K/Akt, and thereby inhibited the GSK3β activity, which would further activated the β-catenin/Cyclin-D signaling pathway and promote NSC proliferation. Besides, after the induction of Se-Met, the number of neurons differentiated from NSCs significantly increased, and the number of astrocytes decreased. After a 90-day treatment with Se-Met (6 μg/mL), the number of hippocampal neurons in 4-month-old AD mice increased significantly, while the one of astrocyte saw a sharp drop. Thus, Se-Met treatment promoted NSCs differentiation into neurons, and subsequently repaired damaged neural systems in AD mice. Being consistent with our in vitro studies, Se-Met acts through the PI3K-Akt- GSK3β-Wnt signaling pathway in vivo. This study provides an unparalleled evidence that selenium (Se) compounds are, to some extent, effective in promoting neurogenesis, and therefore we propose a novel mechanism for Se-Met treatment in AD. - Highlights: • It's the first time to evidence that a selenium (Se) compounds is effective in promoting neurogenesis. • Selenomethionine promotes neural stem cell proliferation and differentiation into neurons. • Selenomethionine activates the PI3K-Akt-GSK3β signaling pathway. • Selenomethionine activates the Wnt signaling pathway.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Substance P preserves pancreatic β-cells in streptozotocin-induced type 1 diabetic mice

Preservation of the pancreatic β-cell population is required for the development of therapies for diabetes, which is caused by a decrease in β-cells. Here, we demonstrate the antidiabetic effects of substance P (SP) in type 1 diabetes (T1D) mice induced with streptozotocin. SP enhanced the compensatory proliferation of β-cells in order to restore β-cells in response to acute injury induced by a single high-dose of streptozotocin. However, SP affected neither the basal proliferation of β-cells nor their apoptosis. In vitro studies by using the INS-1 pancreatic β-cell line showed that SP mediated the increase in the proliferation of β-cells via the activation of Akt. Chronic systemic treatment with SP restored the mass of β-cells and inhibited insulitis in T1D mice induced with multiple low-doses of streptozotocin. Therefore, systemic treatment with SP may be a promising therapeutic strategy for treating diabetes in patients with loss of functional β-cells. - Highlights: • Substance P increased β-cell proliferation in response to acute injury. • Substance P did not protect β-cells from apoptosis. • Substance P preserved β-cell mass and delayed diabetic hyperglycemia.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Yap1/Taz are essential for the liver development in zebrafish

Highlights: • Taz is significantly up-regulated in zebrafish yap1 mutants. • yap1{sup −/−}; taz{sup +/−} embryos are defective in digestive organs development. • Mutations in yap1{sup −/−}; taz{sup +/−} impair cell proliferation in liver and movement of LPM. • Taz can substituteYap1's function in liver development in zebrafish. Hippo pathway regulates cell proliferation and differentiation. Yes-associated protein (Yap) and transcriptional coactivator with PDZ-binding motif (Taz) are effectors of Hippo pathway. The function of Yap/Taz in embryonic liver development has yet to be reported. Here yap1 and taz were found expressed in liver and other digestive organs in zebrafish embryos, and knockout of yap1 or taz did not lead to visible defects during embryogenesis. Interestingly, Taz was significantly increased in yap1 mutants, which may account for their normal development, albeit losing Yap1. However, yap1{sup −/−}; taz{sup +/-} embryos exhibited smaller digestive organs, and more than half of them showed bilateral livers and pancreas and non-looped intestines. Further analysis revealed that the disrupted gene function in yap1{sup −/−}; taz{sup +/-} embryos did not disturb liver bud formation, but instead impaired cell proliferation in liver and movement of the neighboring lateral plate mesoderm (LPM). Overexpression of wild type yap1 or taz could rescue the defective liver phenotypes in yap1{sup −/−}; taz{sup +/-} embryos, indicating that Yap1 cooperate with Taz to regulate the liver development. In addition, Yap1 was found to function in a Tead-dependent manner in the liver development. Our results suggest that Yap1/Taz regulate LPM movement and promote cell proliferation to ensure proper liver development in zebrafish.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Circular RNA HIPK3 promotes gallbladder cancer cell growth by sponging microRNA-124

Highlights: • circHIPK3 is upregulated in established and primary human gallbladder cancer cells. • circHIPK3 siRNA inhibits human gallbladder cancer cell survival and proliferation. • Ectopic circHIPK3 over-expression promotes gallbladder cancer cell proliferation. • circHIPK3 targets miR-124 in gallbladder cancer cells. • circHIPK3 upregulation correlates with miR-124 downregulation in gallbladder cancer tissues. Recent studies have implied that circHIPK3, an abundant circular RNA (circRNA), participates in tumorigenesis and cancer progression. Its expression and potential functions in human gallbladder cancer were examined in this study. We show that circHIPK3 is upregulated in human gallbladder cancer cells. But its level is low in gallbladder epithelial cells. circHIPK3 silencing by targeted siRNA potently inhibited survival and proliferation of established and primary human gallbladder cancer cells, while inducing cell apoptosis. Conversely, ectopic over-expression of circHIPK3 can further promote cancer cell proliferation. In gallbladder cancer cells, circHIPK3 sponged the tumor-suppressive microRNA-124 (miR-124) to sequester and inhibit its activity, thereby leading to increased expression of miR-124 targets, including ROCK1 (rho-associated protein kinase 1) and CDK6 (rho-associated protein kinase). Ectopic over-expression of miR-124 b y a lentiviral vector mimicked and abolished actions by circHIPK3 siRNA in gallbladder cancer cells. At last, we show that circHIPK3 is upregulated in human gallbladder cancer tissues, which is correlated with miR-124 downregulation and ROCK1-CDK6 upregulation. Together, we conclude that circHIPK3 promotes gallbladder cancer cell growth possibly by sponging miR-124. The over-expressed circHIPK3 could be a novel therapeutic target and diagnosis marker of human gallbladder cancer.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Microglia support neural stem cell maintenance and growth

Increasing evidence suggests that disease-associated microglia play a protective role in neurodegenerative diseases. Microglia are known to polarize into two reciprocate forms in response to external cues - inflammatory M1 state and anti-inflammatory M2 state. These cells perform key functions in the development of the brain, such as circuit refinement, neurogenesis, and neuronal growth. In this study, we analyzed the secretion effect of microglia on neural stem/progenitor cell (NSPC) proliferation and differentiation. We cultured adult mouse-derived NSPCs in a conditioned medium from BV2 immortalized microglia without growth factors and evaluated their differentiation. When cultivated with BV2-derived soluble factors in the presence of basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF), NSPCs were able to maintain Nestin expression and showed increased proliferation compared with those cells cultivated with bFGF and EGF only. Moreover, conditioned media from M2-polarized primary microglia, stimulated by IL-10/IL-13, showed supportive effect on NSPC proliferation. These data suggest that microglia support neural stem cell proliferation through secreting neuro-nutritious soluble factors.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Requirement of ERα and basal activities of EGFR and Src kinase in Cd-induced activation of MAPK/ERK pathway in human breast cancer MCF-7 cells

Cadmium (Cd) is a common environmental toxicant and an established carcinogen. Epidemiological studies implicate Cd with human breast cancer. Low micromolar concentrations of Cd promote proliferation of human breast cancer cells in vitro. The growth promotion of breast cancer cells is associated with the activation of MAPK/ERK pathway. This study explores the mechanism of Cd-induced activation of MAPK/ERK pathway. Specifically, the role of cell surface receptors ERα, EGFR, and Src kinase was evaluated in human breast cancer MCF-7 cells treated with 1–3 μM Cd. The activation of ERK was studied using a serum response element (SRE) luciferase reporter assay. Receptor phosphorylation was detected by Western blot analyses. Cd treatment increased both the SRE reporter activity and ERK1/2 phosphorylation in a concentration-dependent manner. Cd treatment had no effect on reactive oxygen species (ROS) generation. Also, blocking the entry of Cd into the cells with manganese did not diminish Cd-induced activation of MAPK/ERK. These results suggest that the effect of Cd was likely not caused by intracellular ROS generation, but through interaction with the membrane receptors. While Cd did not appear to activate either EGFR or Src kinase, their inhibition completely blocked the Cd-induced activation of ERK as well as cell proliferation. Similarly, silencing ERα with siRNA or use of ERα antagonist blocked the effects of Cd. Based on these results, it is concluded that not only ERα, but also basal activities of EGFR and Src kinase are essential for Cd-induced signal transduction and activation of MAPK/ERK pathway for breast cancer cell proliferation. - Highlights: • Low micromolar concentrations of Cd rapidly activate ERK1/2 in MCF-7 cells. • Signal transduction and resulting cell proliferation require EGFR, ERα, and Src. • These findings implicate Cd in promotion of breast cancer.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Quercetin reverses experimental pulmonary arterial hypertension by modulating the TrkA pathway

Pulmonary arterial hypertension (PAH) is characterized by excessive proliferation, resistance to apoptosis, and increased migration of pulmonary artery smooth muscle cells (PASMCs). We hypothesized that quercetin exerts protective effects against this disease; thus, a chronic hypoxia model of PAH was generated using male Sprague-Dawley rats, which were treated with quercetin. In this model, quercetin prevented the development of PAH, right ventricular hypertrophy, and vascular remodeling after exposure to hypoxia. Quercetin inhibited PASMC proliferation and increased the apoptosis of PASMCs in vivo. In vitro, quercetin significantly inhibited hypoxia-induced PASMC proliferation, arrested cells in G1/G0 and inhibited cell migration in a dose-dependent manner. Moreover, our results showed that quercetin increased cyclin D1 protein levels and decreased the protein expression of cyclin B1 and Cdc2. Additionally, quercetin altered the Bax/Bcl-2 ratio and reduced MMP2, MMP9, CXCR4, integrin β1, and integrin α5 expression. Using genome-wide microarray analysis, we found that factors regulating proliferation, apoptosis, cell cycle, and migration were related to the tyrosine receptor kinase A (TrkA) pathway. In addition, activation of the TrkA/AKT signaling cascade during hypoxia was inhibited by quercetin in a dose-dependent manner. Moreover, quercetin alone inhibited the TrkA/AKT signaling pathway, resulting in decreased PASMC migration, cell cycle arrest and the induction of apoptosis. Our data suggest that quercetin is a potential candidate for the treatment of hypoxia-induced PAH. - Graphical abstract: Graphical summary illustrating quercetin reversed hypoxia-induced PAH via modulating the TrkA signal cascade. - Highlights: • Quercetin ameliorate hypoxia-induced PAH and pulmonary arterial remodeling. • Quercetin reverses hypoxia-induced apoptosis resistance, cell cycle arrested and migration in PASMCs. • Quercetin alleviate experimental PAH partially by modulating the TrkA/AKT signaling pathway.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

TrxR2 deficiencies promote chondrogenic differentiation and induce apoptosis of chondrocytes through mitochondrial reactive oxygen species

Thioredoxin reductase 2 (TrxR2) is a selenium (Se) containing protein. Se deficiency is associated with an endemic osteoarthropathy characterized by impaired cartilage formation. It is unclear whether TrxR2 have roles in cartilage function. We examined the effects of TrxR2 on chondrogenic ATDC5 cells through shRNA-mediated gene silencing of TrxR2. We demonstrated TrxR2 deficiencies could enhance chondrogenic differentiation and apoptosis of ATDC5 cells. TrxR2 deficiencies increased accumulation of cartilage glycosaminoglycans (GAGs) and mineralization. TrxR2 deficiencies also stimulated expression of extracellular (ECM) gene including Collagen II and Aggrecan. The enhanced chondrogenic properties were further confirmed by activation of Akt signaling which are required for chondrogenesis. In addition, TrxR2 deficiencies promoted chondrocyte proliferation through acceleration of cell cycle progression by increase in both S and G2/M phase cell distribution accompanied with induction of parathyroid hormone-related protein (PTHrP). Moreover, TrxR2 deficiencies induced chondrocyte death via apoptosis and increased cell sensitivity to exogenous oxidative stress. Furthermore, TrxR2 deficiencies induced emission of mitochondrial reactive oxygen species (ROS) without alteration of mitochondrial membrane potential and intracellular ATP content. Finally, treatment of TrxR2 deficiency cells with N-acetylcysteine (NAC) inhibited mitochondrial ROS production and chondrocyte apoptosis. NAC also prevented chondrogenic differentiation of TrxR2 deficiency cells by suppression of ECM gene expression, GAGs accumulation and mineralization, as well as attenuation of Akt signaling. Thus, TrxR2-mediated mitochondrial integrity is indispensable for chondrogenic differentiation of ATDC5 cells. TrxR2 deficiency-induced impaired proliferation and death of chondrocytes may be the pathological mechanism of the osteoarthropathy due to Se deficiency. Notably, this study also uncover the roles of mitochondrial ROS which could stimulate cartilage ECM synthesis that offer novel insights for development of therapeutic agent to prevent cartilage degeneration in human disease. - Highlights: • TrxR2 deficiencies enhance chondrogenic differentiation. • TrxR2 deficiencies stimulate chondrocyte proliferation. • TrxR2 deficiencies induce chondrocyte apoptosis. • TrxR2 deficiencies increase emission of mitochondrial ROS. • Mitochondrial ROS regulate chondrocyte proliferation, differentiation, and apoptosis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Thiazolidinediones abrogate cervical cancer growth

Peroxisome proliferator-activated receptor gamma (PPAR γ) is activated by thiazolidinedione drugs (TZDs) and can promote anti-cancer properties. We used three TZDs (pioglitazone, rosiglitazone, and ciglitazone) to target cervical cancer cell lines and a nude mouse animal model. Each agent increased activation of PPAR γ, as judged by a luciferase reporter gene assay in three HPV-associated cell lines (CaSki, SiHa, and HeLa cells) while decreasing cellular proliferation in a dose-dependent manner. They also promoted Oil Red O accumulation in treated cell lines and upregulated the lipid differentiation marker adipsin. Interestingly, xenograft HeLa tumors in nude mice treated with 100 mg/kg/day pioglitazone exhibited decreased growth compared to control mice or mice treated with standard cervical chemotherapy. In conclusion, TZDs slow tumor cell growth in vitro and in vivo with decreases in cell proliferation and increases in PPAR γ and adipsin. These agents may be interesting treatments or treatment adjuncts for HPV-associated cancers or perhaps even precancerous conditions. - Highlights: • Thiazolidinediones decreases cervical cancer proliferation. • Pioglitazone increases cervical cancer differentiation. • Pioglitazone decreases tumor growth in mice. • Pioglitazone may be a useful treatment adjunct.

60 APPLIED LIFE SCIENCES↗