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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Functional Toll-like receptor 4 expressed in lactotrophs mediates LPS-induced proliferation in experimental pituitary hyperplasia

Toll like receptor 4 (TLR4) has been characterized for its ability to recognize bacterial endotoxin lipopolysaccharide (LPS). Considering that infections or inflammatory processes might contribute to the progression of pituitary tumors, we analyzed the TLR4 functional role by evaluating the LPS effect on lactotroph proliferation in primary cultures from experimental pituitary tumors, and examined the involvement of PI3K-Akt and NF-κB activation in this effect. In addition, the role of 17β-estradiol as a possible modulator of LPS-induced PRL cell proliferation was further investigated. In estrogen-induced hyperplasic pituitaries, LPS triggered lactotroph cell proliferation. However, endotoxin failed to increase the number of lactotrophs taking up BrdU in normal pituitaries. Moreover, incubation with anti-TLR4 antibody significantly reduced LPS-induced lactotroph proliferation, suggesting a functional role of this receptor. As a sign of TLR4 activation, an LPS challenge increased IL-6 release in normal and tumoral cells. By flow cytometry, TLR4 baseline expression was revealed at the plasma membrane of tumoral lactotrophs, without changes noted in the percentage of double PRL/TLR4 positive cells after LPS stimulus. Increases in TLR4 intracellular expression were detected as well as rises in CD14, p-Akt and NF-κB after an LPS challenge, as assessed by western blotting. The TLR4/PRL and PRL/NF-κB co-localization was also corroborated by immunofluorescence and the involvement of PI3K/Akt signaling in lactotroph proliferation and IL-6 release was revealed through the PI3K inhibitor Ly-294002. In addition, 17β-estradiol attenuated the LPS-evoked increase in tumoral lactotroph proliferation and IL-6 release. Collectively these results demonstrate the presence of functional TLR4 in lactotrophs from estrogen-induced hyperplasic pituitaries, which responded to the proliferative stimulation and IL-6 release induced by LPS through TLR4/CD14, with a contribution of the PI3K-Akt and NF-κB signaling pathways. - Highlights: • In hyperplastic pituitaries, LPS triggered the lactotroph cell proliferation and IL-6 release. • Functional Toll-like receptor 4 (TLR4) is expressed at the plasma membrane of tumoral lactotrophs. • Increases in TLR4 and CD14 intracellular expression levels were detected after an LPS challenge. • The proliferative stimulation and IL-6 release involved the PI3K-Akt pathway and NF-κB activation. • 17β-estradiol attenuated the LPS-evoked tumoral lactotroph proliferation and IL-6 secretion.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

Cell migration or cytokinesis and proliferation? – Revisiting the “go or grow” hypothesis in cancer cells in vitro

The mortality of patients with solid tumors is mostly due to metastasis that relies on the interplay between migration and proliferation. The “go or grow” hypothesis postulates that migration and proliferation spatiotemporally excludes each other. We evaluated this hypothesis on 35 cell lines (12 mesothelioma, 13 melanoma and 10 lung cancer) on both the individual cell and population levels. Following three-day-long videomicroscopy, migration, proliferation and cytokinesis-length were quantified. We found a significantly higher migration in mesothelioma cells compared to melanoma and lung cancer while tumor types did not differ in mean proliferation or duration of cytokinesis. Strikingly, we found in melanoma and lung cancer a significant positive correlation between mean proliferation and migration. Furthermore, non-dividing melanoma and lung cancer cells displayed slower migration. In contrast, in mesothelioma there were no such correlations. Interestingly, negative correlation was found between cytokinesis-length and migration in melanoma. FAK activation was higher in melanoma cells with high motility. We demonstrate that the cancer cells studied do not defer proliferation for migration. Of note, tumor cells from various organ systems may differently regulate migration and proliferation. Furthermore, our data is in line with the observation of pathologists that highly proliferative tumors are often highly invasive. - Highlights: • We investigated the “go or grow” hypothesis in human cancer cells in vitro. • Proliferation and migration positively correlate in melanoma and lung cancer cells. • Duration of cytokinesis and migration shows inverse correlation. • Increased FAK activation is present in highly motile melanoma cells.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Polyphosphate induces matrix metalloproteinase-3-mediated proliferation of odontoblast-like cells derived from induced pluripotent stem cells

Inorganic polyphosphate [Poly(P)] may represent a physiological source of phosphate and has the ability to induce bone differentiation in osteoblasts. We previously reported that cytokine-induced matrix metalloproteinase (MMP)-3 accelerates the proliferation of purified odontoblast-like cells. In this study, MMP-3 small interfering RNA (siRNA) was transfected into odontoblast-like cells derived from induced pluripotent stem cells to investigate whether MMP-3 activity is induced by Poly(P) and/or is associated with cell proliferation and differentiation into odontoblast-like cells. Treatment with Poly(P) led to an increase in both cell proliferation and additional odontoblastic differentiation. Poly(P)-treated cells showed a small but significant increase in dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP-1) mRNA expression, which are markers of mature odontoblasts. The cells also acquired additional odontoblast-specific properties including adoption of an odontoblastic phenotype typified by high alkaline phosphatase (ALP) activity and a calcification capacity. In addition, Poly(P) induced expression of MMP-3 mRNA and protein, and increased MMP-3 activity. MMP-3 siRNA-mediated disruption of the expression of these effectors potently suppressed the expression of odontoblastic biomarkers ALP, DSPP, and DMP-1, and blocked calcification. Interestingly, upon siRNA-mediated silencing of MMP-3, we noted a potent and significant decrease in cell proliferation. Using specific siRNAs, we revealed that a unique signaling cascade, Poly(P)→MMP-3→DSPP and/or DMP-1, was intimately involved in the proliferation of odontoblast-like cells. - Highlights: • Polyphosphate increases proliferation of iPS cell-derived odontoblast-like cells. • Polyphosphate-induced MMP-3 results in an increase of cell proliferation. • Induced cell proliferation involves MMP-3, DSPP, and/or DMP-1 sequentially. • Induced MMP-3 also results in an increase of odontoblastic differentiation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Roxithromycin inhibits VEGF-induced human airway smooth muscle cell proliferation: Opportunities for the treatment of asthma

Asthma is a chronic respiratory disease characterized by reversible airway obstruction with persistent airway inflammation and airway remodelling, which is associated with increased airway smooth muscle (ASM) mass. Roxithromycin (RXM) has been widely used in asthma treatment; however, its mechanism of action is poorly understood. Vascular endothelial growth factor (VEGF) has been implicated in inflammatory and airway blood vessel remodelling in patients with asthma, and shown to promote ASM cell proliferation. Here, we investigated the effect of RXM on VEGF-induced ASM cell proliferation and attempted to elucidate the underlying mechanisms of action. We tested the effect of RXM on proliferation and cell cycle progression, as well as on the expression of phospho-VEGF receptor 2 (VEGFR2), phospho-extracellular signal-regulated kinase 1/2 (ERK1/2), phospho-Akt, and caveolin-1 in VEGF-stimulated ASM cells. RXM inhibited VEGF-induced ASM cell proliferation and induced cell cycle arrest. Additionally, VEGF-induced ASM cell proliferation was suppressed by inhibiting the activity of ERK1/2, but not that of Akt. Furthermore, RXM treatment inhibits VEGF-induced activation of VEGFR2 and ERK and downregulation of caveolin-1 in a dose-dependent manner. RXM also inhibited TGF-β-induced VEGF secretion by ASM cells and BEAS-2B cells. Collectively, our findings suggest that RXM inhibits VEGF-induced ASM cell proliferation by suppression of VEGFR2 and ERK1/2 activation and caveolin-1 down-regulation, which may be involved in airway remodelling. Further elucidation of the mechanisms underlying these observations should enable the development of treatments for smooth muscle hyperplasia-associated diseases of the airway such as asthma. - Highlights: • RXM inhibited VEGF-induced ASM cell proliferation and induced cell cycle arrest. • VEGF-induced cell proliferation was suppressed by inhibiting the activity of ERK1/2. • RXM inhibits activation of VEGFR2 and ERK and downregulation of caveolin-1. • RXM inhibited TGF-β-induced VEGF secretion by ASM cells and BEAS-2B cells. • Our findings expand our knowledge of the role of RXM in airway remodelling.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

PTEN silencing enhances neuronal proliferation and differentiation by activating PI3K/Akt/GSK3β pathway in vitro

Highlights: • PTEN had a dual effect on the neuronal cells in vitro. • PTEN knockdown significantly promoted neuronal cell proliferation and differentiation. • PTEN knockdown activated Akt/GSK3β and Wnt/β-catenin pathways in vitro. • GSK3β as a key node involved in PTEN controlling cell proliferation and differentiation in PC12 cells. • PTEN-GSK3β pathway modulated neuronal proliferation via β-catenin. The failure of neuronal proliferation and differentiation is a major obstacle for neural repair and regeneration after traumatic central nervous system (CNS) injury. PTEN acts as an intrinsic brake on the neuronal cells, but its roles and mechanism still remain to be clarified. Herein, for the first time we confirmed that PTEN had a dual effect on the neuronal cells in vitro. Firstly, we found that PTEN knockdown significantly promoted cell proliferation and differentiation. Then, PTEN knockdown activated PI3K/Akt and Wnt/β-catenin pathways in vitro. Further evidence revealed that GSK3β as a key node involved in PTEN controlling cell proliferation and differentiation in PC12 cells. In addition, we identified that PTEN-GSK3β pathway modulated neuronal proliferation via β-catenin. Taken together, these results suggest that PTEN silencing enhances neuronal proliferation and differentiation by activating PI3K/Akt/GSK3β pathway that it may be a promising therapeutic approach for CNS injury.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

GRP78 Promotes Hepatocellular Carcinoma proliferation by increasing FAT10 expression through the NF-κB pathway

Highlights: • GRP78 positively regulates FAT10 expression and accelerates HCC proliferation. • GRP78 and FAT10 exhibit a positive correlation with patient survival. • GRP78 modulated FAT10 via the NF-κB signaling pathway. • GRP78 could activate NF-κB signaling by modulating the phosphorylation of IKKα/β⊡. Glucose-regulated protein 78(GRP78) and the ubiquitin-like protein FAT10 each promote proliferation in hepatocellular carcinoma(HCC). However, the relationship of GRP78 and FAT10 in HCC proliferation are still not known. In this study, we found that GRP78 and FAT10 were significantly overexpressed in HCC tissues compare with adjacent non-cancerous tissues, and a positive correlation was found between their expression and associated proliferation characteristics. High expression of GRP78 and FAT10 were positively correlated with tumor proliferation and poor prognosis in HCC. Moreover, GRP78 knockdown reduced FAT10 expression and suppressed HCC proliferation in vitro and in vivo. The effects of GRP78 knockdown were rescued by FAT10 up-regulation, whereas FAT10 knockdown reduced HCC proliferation enhanced by GRP78 up-regulation. Furthermore, GRP78 modulated FAT10 expression by regulating the NF-κB pathway, direct activation of the NF-κB pathway increased the expression of FAT10, a gene counteracting the tumor suppressor p53. Taken together, these results suggest that this newly identified GRP78–NF-κB–FAT10 axis will provide novel insight into the understanding of the regulatory mechanisms of proliferation in human HCC.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Notch1 promotes mouse spinal neural stem and progenitor cells proliferation via p-p38-pax6 induced cyclin D1 activation

Highlights: • Notch1 promotes the proliferation of adult mouse spinal cord derived NSPCs. • Notch1 regulates NSPC proliferation via the p-p38-pax6 pathway. • Pax6 upregulates cyclin D1 expression, inducing the transition of NSPCs to S-phase. Neural stem and progenitor cells (NSPCs) are important for nerve regeneration after spinal cord injury (SCI). Their proliferation, however, is limited. In this study, we investigated the role of Notch1 signaling in NSPC proliferation using adult mouse spinal cord derived NSPCs. We observed that Notch1 promoted proliferation of NSPCs and that Notch1 overexpression led to an expansion of cells in the S-phase and increased cyclin D1 expression. When investigating the functional relationship between Notch1, p-p38 and Pax6, we found that Notch1 suppressed p-p38 while promoting Pax6 expression. Functional inhibition of p38 with SB202190 led to increased Pax6 expression and to proliferation, as determined by BrdU. Furthermore, we confirmed that Pax6 induced proliferation in adult mouse spinal cord derived NSPCs. In conclusion, we demonstrate that Notch1 promotes the proliferation of mouse spinal NSPCs via a p-p38-pax6-cyclin D1 signaling pathway. This pathway constitutes a promising new therapeutic target for SCI treatment.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

FTO regulates myoblast proliferation by controlling CCND1 expression in an m6A-YTHDF2-dependent manner

Highlights: • Silencing FTO delays cell cycle and inhibits cell proliferation. • FTO regulates cell proliferation depending on its m{sup 6}A demethylation activity. • Silencing FTO suppresses CCND1 expression via YTHDF2-mediated mRNA degradation. • Knockdown YTHDF2 eliminates the cell cycle arrest in FTO-deficient cells. N6-Methyladenosine (m{sup 6}A) modification is the most abundant chemical modification in mRNA, and it participates in various biological processes, such as cell differentiation and proliferation. However, little is known about the function of m{sup 6}A demethylase fat mass and obesity-associated (FTO) in myoblast proliferation. Here, we demonstrated that knockdown of FTO can significantly inhibit myoblast proliferation and promote apoptosis. RNA sequencing analysis revealed that a lot of downregulated genes in FTO knockdown cells are associated with cell cycle and apoptosis. Furthermore, silencing FTO drastically decreased cyclin D1 (CCND1) expression through YTHDF2-mediated mRNA degradation, thereby delaying the progression of G1 phase, and leading to impaired myoblast proliferation. These findings unraveled that FTO regulates myoblast proliferation by controlling CCND1 expression in an m{sup 6}A-YTHDF2-dependent manner, which highlights the critical roles of m{sup 6}A modification in myoblast proliferation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

ER-α36 mediates estrogen-stimulated MAPK/ERK activation and regulates migration, invasion, proliferation in cervical cancer cells

Objective: Estrogen receptor alpha 36 (ER-α36), a truncated variant of ER-α, is different from other nuclear receptors of the ER-α family. Previous findings indicate that ER-α36 might be involved in cell growth, proliferation, and differentiation in carcinomas and primarily mediates non-genomic estrogen signaling. However, studies on ER-α36 and cervical cancer are rare. This study aimed to detect the expression of ER-α36 in cervical cancer; the role of ER-α36 in 17-β-estradiol (E2)-induced invasion, migration and proliferation of cervical cancer; and their probable molecular mechanisms. Methods: Immunohistochemistry and immunofluorescence were used to determine the location of ER-α36 in cervical cancer tissues and cervical cell lines. CaSki and HeLa cell lines were transfected with lentiviruses to establish stable cell lines with knockdown and overexpression of ER-α36. Wound healing assay, transwell invasion assay, and EdU incorporation proliferation assay were performed to evaluate the migration, invasion, and proliferation ability. The phosphorylation levels of mitogen-activated protein kinases/extracellular signal-regulated kinase (MAPK/ERK) signaling molecules were examined with western blot analysis. Results: ER-α36 expression was detected in both cervical cell lines and cervical cancer tissues. Downregulation of ER-α36 significantly inhibited cell invasion, migration, and proliferation. Moreover, upregulation of ER-α36 increased the invasion, migration, and proliferation ability of CaSki and HeLa cell lines. ER-α36 mediates estrogen-stimulated MAPK/ERK activation. Conclusion: ER-α36 is localized on the plasma membrane and cytoplasm in both cervical cancer tissues and cell lines. ER-α36 mediates estrogen-stimulated MAPK/ERK activation and regulates migration, invasion, proliferation in cervical cancer cells. - Highlights: • ER-α36 is expressed on both cervical cell lines and cervical cancer tissues. • ER-α36 mediates estrogen-stimulated cell invasion, migration and proliferation of cervical cancer cell lines. • ER-α36 mediates estrogen-stimulated MAPK/ERK activation in cervical cancer cell lines.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

RELM-β promotes human pulmonary artery smooth muscle cell proliferation via FAK-stimulated surviving

Resistin-like molecule-β (RELM-β), focal adhesion kinase (FAK), and survivin may be involved in the proliferation of cultured human pulmonary artery smooth muscle cells (HPAMSCs), which is involved in pulmonary hypertension. HPAMSCs were treated with human recombinant RELM-β (rhRELM-β). siRNAs against FAK and survivin were transfected into cultured HPASMCs. Expression of FAK and survivin were examined by RT-PCR and western blot. Immunofluorescence was used to localize FAK. Flow cytometry was used to examine cell cycle distribution and cell death. Compared to the control group, all rhRELM-β-treated groups demonstrated significant increases in the expression of FAK and survivin (P<0.05). rhRELM-β significantly increased the proportion of HPASMCs in the S phase and decreased the proportion in G0/G1. FAK siRNA down-regulated survivin expression while survivin siRNA did not affect FAK expression. FAK siRNA effectively inhibited FAK and survivin expression in RELM-β-treated HPASMCs and partially suppressed cell proliferation. RELM-β promoted HPASMC proliferation and upregulated FAK and survivin expression. In conclusion, results suggested that FAK is upstream of survivin in the signaling pathway mediating cell proliferation. FAK seems to be important in RELM-β-induced HPASMC proliferation, partially by upregulating survivin expression. - Highlights: • rhRELM-β increased the expression of FAK and survivin. • rhRELM-β increased the proportion of HPASMCs in the S phase. • FAK is upstream of survivin in the signaling pathway mediating cell proliferation. • FAK is important in RELM-β-induced HPASMC proliferation, partly via survivin.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2011

Silencing tissue inhibitors of metalloproteinases (TIMPs) with short interfering RNA reveals a role for TIMP-1 in hepatic stellate cell proliferation

Research highlights: {yields} Myofibroblastic, activated hepatic stellate cells (HSC) play a pivotal role in the development of liver fibrosis. {yields} We used short interfering RNA (siRNA) to investigate the effects of autocrine TIMP-1 and -2 on HSC proliferation. {yields} Specific silencing of TIMP-1, but not TIMP-2, significantly reduces HSC proliferation and is associated with reduced Akt phosphorylation. {yields} TIMP-1 is localised in part to the HSC nucleus. {yields} TIMP-1 might promote liver fibrosis by means other than its previously described anti-apoptotic effect on HSC. -- Abstract: Myofibroblastic, activated hepatic stellate cells (HSC) play a pivotal role in the development of liver fibrosis through the secretion of fibrillar collagens and the tissue inhibitors of metalloproteinase (TIMP)-1 and -2. TIMPs are believed to promote hepatic fibrosis by inhibiting both matrix degradation and apoptosis of HSC. In other cell types, there is evidence that TIMP-1 has effects on proliferation, however the role of TIMPs in the regulation of HSC proliferation remains unexplored. Therefore, we have used short interfering RNA (siRNA) to investigate the effects of autocrine TIMP-1 and -2 on HSC proliferation. TIMP-1 and -2 siRNA were highly effective, producing peak target protein knockdown compared to negative control siRNA of 92% and 63%, respectively. Specific silencing of TIMP-1, using siRNA, significantly reduced HSC proliferation. TIMP-1 was localised in part to the HSC nucleus and TIMP-1 siRNA resulted in loss of both cytoplasmic and nuclear TIMP-1. Attenuated proliferation was associated with reduced Akt phosphorylation and was partially rescued by addition of recombinant TIMP-1. We have revealed a novel autocrine mitogenic effect of TIMP-1 on HSC, which may involve Akt-dependent and specific nuclear mechanisms of action. We suggest that TIMP-1 might promote liver fibrosis by means other than its previously described anti-apoptotic effect on HSC. Moreover, these findings, together with our previous reports and the emerging data from in vivo studies of TIMP inhibition, provide strong evidence that TIMP-1 is mechanistically central to liver fibrosis and an important potential therapeutic target.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2011

Aspirin-induced AMP-activated protein kinase activation regulates the proliferation of vascular smooth muscle cells from spontaneously hypertensive rats

Highlights: {yields} Aspirin-induced AMPK phosphorylation was greater in VSMC from SHR than WKY. {yields} Aspirin-induced AMPK phosphorylation inhibited proliferation of VSMC from SHR. {yields} Low basal AMPK phosphorylation in SHR elicits increased VSMC proliferation. {yields} Inhibition of AMPK restored decreased VSMC proliferation by aspirin in SHR. {yields} Aspirin exerts anti-proliferative effect through AMPK activation in VSMC from SHR. -- Abstract: Acetylsalicylic acid (aspirin), used to reduce risk of cardiovascular disease, plays an important role in the regulation of cellular proliferation. However, mechanisms responsible for aspirin-induced growth inhibition are not fully understood. Here, we investigated whether aspirin may exert therapeutic effects via AMP-activated protein kinase (AMPK) activation in vascular smooth muscle cells (VSMC) from wistar kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Aspirin increased AMPK and acetyl-CoA carboxylase phosphorylation in a time- and dose-dependent manner in VSMCs from WKY and SHR, but with greater efficacy in SHR. In SHR, a low basal phosphorylation status of AMPK resulted in increased VSMC proliferation and aspirin-induced AMPK phosphorylation inhibited proliferation of VSMCs. Compound C, an AMPK inhibitor, and AMPK siRNA reduced the aspirin-mediated inhibition of VSMC proliferation, this effect was more pronounced in SHR than in WKY. In VSMCs from SHR, aspirin increased p53 and p21 expression and inhibited the expression of cell cycle associated proteins, such as p-Rb, cyclin D, and cyclin E. These results indicate that in SHR VSMCs aspirin exerts anti-proliferative effects through the induction of AMPK phosphorylation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2011

NR2B-containing NMDA receptors promote neural progenitor cell proliferation through CaMKIV/CREB pathway

Highlights: {yields} The NR2B component of the NMDARs is important for the NSPC proliferation. {yields} pCaMKIV and pCREB exist in NSPCs. {yields} The CaMKIV/CREB pathway mediates NSPC proliferation. -- Abstract: Accumulating evidence indicates the involvement of N-methyl-D-aspartate receptors (NMDARs) in regulating neural stem/progenitor cell (NSPC) proliferation. Functional properties of NMDARs can be markedly influenced by incorporating the regulatory subunit NR2B. Here, we aim to analyze the effect of NR2B-containing NMDARs on the proliferation of hippocampal NSPCs and to explore the mechanism responsible for this effect. NSPCs were shown to express NMDAR subunits NR1 and NR2B. The NR2B selective antagonist, Ro 25-6981, prevented the NMDA-induced increase in cell proliferation. Moreover, we demonstrated that the phosphorylation levels of calcium/calmodulin-dependent protein kinase IV (CaMKIV) and cAMP response element binding protein (CREB) were increased by NMDA treatment, whereas Ro 25-6981 decreased them. The role that NR2B-containing NMDARs plays in NSPC proliferation was abolished when CREB phosphorylation was attenuated by CaMKIV silencing. These results suggest that NR2B-containing NMDARs have a positive role in regulating NSPC proliferation, which may be mediated through CaMKIV phosphorylation and subsequent induction of CREB activation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2011

Loss of DLK expression in WI-38 human diploid fibroblasts induces a senescent-like proliferation arrest

Highlights: {yields} Role of DLK in cell proliferation. {yields} Modulation of DLK expression during cell cycle progression. {yields} DLK knockdown induces proliferation arrest and senescence. {yields} DLK-depleted cells display loss of cyclin D1 and up-regulation of p21. {yields} DLK participates in cell proliferation by modulating cell cycle regulator expression. -- Abstract: DLK, a serine/threonine kinase that functions as an upstream activator of the mitogen-activated protein kinase (MAPK) pathways, has been shown to play a role in development, cell differentiation, apoptosis and neuronal response to injury. Interestingly, recent studies have shown that DLK may also be required for cell proliferation, although little is known about its specific functions. To start addressing this issue, we studied how DLK expression is modulated during cell cycle progression and what effect DLK depletion has on cell proliferation in WI-38 fibroblasts. Our results indicate that DLK protein levels are low in serum-starved cells, but that serum addition markedly stimulated it. Moreover, RNA interference experiments demonstrate that DLK is required for ERK activity, expression of the cell cycle regulator cyclin D1 and proliferation of WI-38 cells. DLK-depleted cells also show a senescent phenotype as revealed by senescence-associated galactosidase activity and up-regulation of the senescence pathway proteins p53 and p21. Consistent with a role for p53 in this response, inhibition of p53 expression by RNA interference significantly alleviated senescence induced by DLK knockdown. Together, these findings indicate that DLK participates in cell proliferation and/or survival, at least in part, by modulating the expression of cell cycle regulatory proteins.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

MicroRNA-27a promotes myoblast proliferation by targeting myostatin

Highlights: Black-Right-Pointing-Pointer We identified a myogenic role for miR-27a and a new target, myostatin. Black-Right-Pointing-Pointer The miR-27a was confirmed to target myostatin 3 Prime UTR. Black-Right-Pointing-Pointer miR-27a is upregulated and myostatin is downregulated during myoblast proliferation. Black-Right-Pointing-Pointer miR-27a promotes myoblast proliferation by reducing the expression of myostatin. -- Abstract: MicroRNAs (miRNAs) are a class of endogenous non-coding RNAs that play critical roles in skeletal muscle development as well as in regulation of muscle cell proliferation and differentiation. However, the role of miRNAs in myoblast proliferation remains poorly understood. Here we found that the expression of miR-27a was increased during proliferation of C2C12 myoblasts. Moreover, overexpression of miR-27a in C2C12 cells promoted myoblast proliferation by reducing the expression of myostatin, a critical inhibitor of skeletal myogenesis. In addition, the miR-27a was confirmed to target myostatin 3 Prime UTR by a luciferase reporter analysis. Together, these results suggest that miR-27a promotes myoblast proliferation through targeting myostatin.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

Nesfatin-1 inhibits ovarian epithelial carcinoma cell proliferation in vitro

Highlights: •Nesfatin-1 inhibits the proliferation and growth of HO-8910 cells by G1 phase arrest. •Nesfatin-1 enhances HO-8910 cell apoptosis. •Nesfatin-1 inhibits HO-8910 cell proliferation via mTOR and RhoA/ROCK signaling pathway. •The first report of nesfatin-1-mediated proliferation in ovarian epithelial carcinoma. -- Abstract: Nesfatin-1, an 82-amino-acid peptide derived from a 396-amino-acid precursor protein nucleobindin 2 (NUCB2), was originally identified in hypothalamic nuclei involved in the regulation of food intake. It was recently reported that nesfatin-1 is a novel depot specific adipokine preferentially produced by subcutaneous tissue, with obesity- and food deprivation-regulated expression. Although a relation between ovarian cancer mortality and obesity has been previously established, a role of nesfatin-1 in ovarian epithelial carcinoma remains unknown. The aim of the present study is to examine the effect of nesfatin-1 on ovary carcinoma cells proliferation. We found that nesfatin-1 inhibits the proliferation and growth of HO-8910 cells by G1 phase arrest, this inhibition could be abolished by nesfatin-1 neutralizing antibody. Nesfatin-1 enhances HO-8910 cell apoptosis, activation of mammalian target of rapamycin (mTOR) and RhoA/ROCK signaling pathway block the effects of nesfatin-1-induced apoptosis, therefore reverses the inhibition of HO-8910 cell proliferation by nesfatin-1. In conclusion, the present study demonstrated that nesfatin-1 can inhibit the proliferation in human ovarian epithelial carcinoma cell line HO-8910 cells through inducing apoptosis via mTOR and RhoA/ROCK signaling pathway. This study provides a novel regulatory signaling pathway of nesfatin-1-regulated ovarian epithelial carcinoma growth and may contribute to ovarian cancer prevention and therapy, especially in obese patients.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

CDK-associated Cullin 1 promotes cell proliferation with activation of ERK1/2 in human lung cancer A549 cells

Highlights: •CDK-associated Cullin 1 (CAC1) expression increases in human lung carcinoma. •CAC1 promotes the proliferation of lung cancer A549 cells. •CAC1 promotes human lung cancer A549 cell proliferation with activation of ERK1/2. -- Abstract: Lung cancer is one of the most common causes of cancer-related death in the world, but the mechanisms remain unknown. In this study, we investigated the expression of CDK-associated Cullin 1 (CAC1) in lung cancer, the effect of CAC1 on the proliferation of human lung cancer A549 cells, and the activation of signaling pathways of mitogen-activated protein kinases (MAPKs). Results showed that CAC1 expression was higher levels in human lung carcinoma than normal lung tissue, and CAC1 siRNA reduced the proliferation of lung cancer A549 cells by decreasing cell activity and cell division in vitro. The proportion of cells treated with CAC1 siRNA increased in the G1 phase and decreased in the S and G2/M phase, indicative of G1 cell cycle arrest. Furthermore, the proportions of early/late apoptosis in lung cancer A549 cells were enhanced with CAC1 siRNA treatment. It was also found that activation of extracellular signal-regulated protein kinase (ERK) and p38 signaling pathways were involved in the proliferation of A549 cells. After CAC1 siRNA treatment, p-ERK1/2 levels decreased, and meanwhile p-p38 level increased, A549 cell proliferation increased when ERK1/2 signaling is activated by PMA. Our findings demonstrated that CAC1 promoted the proliferation of human lung cancer A549 cells with activation of ERK1/2 signaling pathways, suggesting a potential cure target for treatment of human lung cancer.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

EPO-independent functional EPO receptor in breast cancer enhances estrogen receptor activity and promotes cell proliferation

Highlights: • New anti-human EPOR antibody confirms full-length EPOR expression in breast cancer cells. • Proliferation of breast cancer cells is not affected by rhEPO treatment in vitro. • EPOR knockdown impairs proliferation of ERa positive breast cancer cells. • EPOR knockdown reduces AKT phosphorylation and ERa activity. - Abstract: The main function of Erythropoietin (EPO) and its receptor (EPOR) is the stimulation of erythropoiesis. Recombinant human EPO (rhEPO) is therefore used to treat anemia in cancer patients. However, clinical trials have indicated that rhEPO treatment might promote tumor progression and has a negative effect on patient survival. In addition, EPOR expression has been detected in several cancer forms. Using a newly produced anti-EPOR antibody that reliably detects the full-length isoform of the EPOR we show that breast cancer tissue and cells express the EPOR protein. rhEPO stimulation of cultured EPOR expressing breast cancer cells did not result in increased proliferation, overt activation of EPOR (receptor phosphorylation) or a consistent activation of canonical EPOR signaling pathway mediators such as JAK2, STAT3, STAT5, or AKT. However, EPOR knockdown experiments suggested functional EPO receptors in estrogen receptor positive (ERα{sup +}) breast cancer cells, as reduced EPOR expression resulted in decreased proliferation. This effect on proliferation was not seen in ERα negative cells. EPOR knockdown decreased ERα activity further supports a mechanism by which EPOR affects proliferation via ERα-mediated mechanisms. We show that EPOR protein is expressed in breast cancer cells, where it appears to promote proliferation by an EPO-independent mechanism in ERα expressing breast cancer cells.

60 APPLIED LIFE SCIENCES↗