bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 3066: Effect of stable knockdown of NOX1 gene expression with siRNA in human colon cancer cells
Authors: Juhasz Agnes , Antony Smitha , Wu Yongzhong , Lu Jiamo , Jiang Guojian , Liu Han , Roy Krishnendu , Doroshow James H. 
Published: August 2012

Abstract
NADPH oxidase (Nox)-dependent reactive oxygen species (ROS) play a critical role in cell signaling, cell proliferation, and mitogenesis. We have previously shown that silencing NOX1 gene expression with siRNA decreases cell growth and angiogenesis in human HT-29 colon cancer xenografts. To investigate the mechanism of growth inhibition, we studied cell cycle and signaling pathways. We found using RT-PCR and Western analysis that the expression of the INK4 inhibitors (p15, p18, p19), as well as CDK6, phospho-Cyclin E, Cyclin E, and Cyclin D1 were all decreased when NOX1 was decreased by &gt;80%. We detected important changes in the Raf-MEK-ERK pathway that were associated with NOX1 knockdown. Our stable knock-out cells (clone 6A) showed lower phosphorylation of Rac1, c-Raf, MEK1/2, ERK1/2, p90RSK and CREB. To understand this observation, we studied the activity of Tyr and Ser/Threonine protein phosphatases (PP) in our stable siRNA containing cells (6A) compared to stable scrambled siRNA containing cells (SA) and parental HT-29 cells. PTP1B activity was elevated (100.4+4.4 pmol of phosphate/min/µg) in 6A cells compared to both SA (69.2+3.8) and parental (47.8+2.1) cell controls, P&lt;0.05. Serine/Threonine protein phosphatases demonstrated a similar pattern; elevated in 6A cells (127.3+3.8 pmol of phosphate/min/µg) versus both SA cells (91.7+2.1) and the parental line (88.9+1.9), P&lt;0.05. To demonstrate that protein phosphatases play a key role in the regulation of ERK-CREB signaling, we used a c-Raf antibody to immunoprecipitate the c-Raf-PPs complex, and detected PTP1B and PP2C proteins by Western analysis. These data indicate that siRNA-mediated gene silencing of Nox1 deactivated ERK-CREB signaling, and that increased activity of protein phosphatases, that occur as a consequence of decreased Nox-mediated ROS formation, might play role in modifying the growth enhancing effects of the MAP kinase pathway in HT-29 colon cancer cells.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3066. doi:1538-7445.AM2012-3066
Abstract 3068: Hedgehog signaling regulates drug sensitivity by targeting ABC transporters in epithelial ovarian cancer (EOC)
Authors: Chen Yi , Bieber Marcia , Bhat Neelima , Teng Nelson N.H. 
Published: August 2012

Abstract
A major challenge of successful chemotherapy in treatment of ovarian cancer is overcoming intrinsic or acquired multi-drug resistance caused mostly by the active efflux mediated by ATP-binding cassette (ABC) transporters. The regulation of these transporters in ovarian cancer is poorly understood. Our research shows that in ovarian cancer, abnormal regulation of the hedgehog (Hh) signaling pathway is involved in regulation of ABC transporters. Hh is a known regulator of cancer cell proliferation and differentiation in several other types of invasive and metastatic malignancies. Our work on Gli1, a key Hh downstream signaling gene, has shown frequent activation of the Hh pathway in ovarian cancer. Inhibition of the Hh signaling pathway by inhibitors or Gli1 siRNA increases ABC gene expression levels and the response of ovarian cancer cells to certain chemotherapeutic drugs. The mechanism underlying is a direct association of Gli1 with a specific consensus sequence located in the promoter region of ABC genes. This study provides new information in the knowledge of ABC gene regulation and will contribute to generating new targets/markers to detect and anticipate ovarian cancer patient chemotherapy drug sensitivity which could lead to more effective treatments and improved survival.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3068. doi:1538-7445.AM2012-3068
Abstract 307: Acquisition of the invasive phenotype and EMT profile by CXCL7 transfection
Authors: Kosir Mary A. , Ju Donghong 
Published: August 2012

Abstract
Introduction: The expression of CXCL7 is associated with the invasive phenotype through interaction with the CXCL7/CXCR2 axis and heparan sulfate. A component of the epithelial to mesenchymal transition (EMT) is degradation of extracellular matrix and acquisition of migration, both of which support invasiveness. The purpose of this study is to quantify the expression of genes associated with EMT by CXCL7-expressing cells with the invasive phenotype. Methods: Total RNA from CXCL7-transfected breast cells (MCF10AT) was tested for relative gene expression using RT2 ProfilerTM PCR array for EMT (SABiosciences). Vector transfected cells were compared. Each result was verified by real time PCR assay. Results: The expression of GNG11 and TCF4 was upregulated and SPP1 downregulated as expected for the EMT profile. Specifically, GNG11 (Guanine nucleotide binding protein (G protein), gamma 11) expression was increased 2.94 fold and TCF4 (Transcription factor 4) increased 1.89 fold. The expression of SPP1 (Secreted phosphoprotein 1) was decreased by 6.8 fold. The expression of ZEB2 (Zinc finger E-box binding homeobox 2) was decreased by 1.96 as a transcription factor. Summary: The CXCL7-transfected cells with invasive phenotype express genes associated with the EMT expression profile including G-protein signaling pathway.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 307. doi:1538-7445.AM2012-307
Abstract 3073: EphrinA1 inhibits non small cell lung cancer (NSCLC) tumor growth via induction of miRNA-122
Authors: Sukka-Ganesh BhagyaLaxmi , Mohammed Kamal A. , Goldberg Eugene P. , Nasreen Najmunnisa 
Published: August 2012

Abstract
Introduction: Ephrin-A1 ligand exerts anti-oncogeneic effect in NSCLC tumor cells through activation and down regulation of the EphA2 receptor. Alteration in their expression levels is associated with aggressive tumor growth. The underlying mechanisms for altered expression of Ephrin-A1 and EphA2 receptor are yet to be defined. MicroRNAs (miR) are small non-coding RNAs play a key role in tumorogenesis. MiR-122 directly targets Bcl-w which harbours a putative miR-122 binding site in its 3′-UTR. However, if EphrinA1 induces miR-122 expression in NSCLC is not known. Here we demonstrate a novel mechanism of EphrinA1 mediated miR-122 signalling in the inhibition of NSCLC growth. Methods: NSCLC cell lines (A-549 and H-23) were activated with Ephrin-A1 over time (3 hr, 6hr, 12hr and 24 hr) and miR-122 expression was measured by Real-time PCR and In situ hybridization. Furthermore, in order to understand the underlying mechanisms EphrinA-1 mediated signalling, Bach-1 and Bcl-w protein expression were studied through Western blotting analysis. In addition, Tumor growth and Cell migration studies were performed in Ephrin-A1 activated and premiR-122 transfected NSCLC cells. Results: The data from this study demonstrates that Ephrin-A1 activation of NSCLC enhanced Bach-1 and miR-122 expression over time. When NSCLC transfected with pre-miR-122, we noticed a significant down-regulation of Bcl-w gene and protein expression, suggesting miR-122 specifically targets to anti-apoptotic gene Bcl-w and induced apoptosis in NSCLC. In situ hybridization demonstrated strong signals for miR-122 in EphrinA1 activated NSCLC cells as compared to control cells. Furthermore, knock down of Bach-1 gene expression using siRNA, showed significant down-regulation of miR-122, suggesting Ephrin-A1 mediated signalling is regulated by the transcription factor Bach-1 via miR-122 in NSCLC. In addition, this was confirmed by transfection of NSCLC by premiR-122 that inhibited tumor growth and migration of NSCLC cells. Conclusions: Our study suggests that Ephrin-A1 mediated signalling is regulated by the transcription factor Bach-1 via miR-122 expression. MiR-122 targets the anti-apoptotic gene Bcl-w and triggers apoptosis in NSCLC cells. The present study provides a new insight into the complex regulating pathways of Ephrin-A1/Eph receptor, and also understanding the direct role of miRNA-122 in Ephrin-A1 mediated signalling pathway that may lead to new therapeutic strategies for lung adenocarcinoma. Funding Source: RC1 form Florida Department of Health; VA Merit Review
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3073. doi:1538-7445.AM2012-3073
Abstract 3075: NOTCH1 dimerization directly activates Rag1 and Rag2 in murine T-cell leukemia
Authors: Liu Hudan , Yashiro-Ohtani Yumi , Chi Anthony W.S. , Pear Warren S. 
Published: August 2012

Abstract
The NOTCH transcriptional complex forms dimer in the nucleus on some target gene promoters/enhancers bearing sequence-paired sites (SPS) that are properly spaced and orientated. We previously reported that NOTCH1 dimerization is required for the pathogenesis of T-cell acute lymphoblastic leukemia (T-ALL). Although NOTCH1 dimers are suggested to regulate only a subset of target genes, identification of these targets and analysis of their function to mediate NOTCH1-induced T-ALL are very limited. Based on a genome-wide microarray gene profiling to screen dimer-dependent targets in a murine T-ALL cell line T6E, we report here that both Rag1 and Rag2 are direct dimeric NOTCH1 transcriptional targets. We also defined a SPS in the upstream enhancer region of Rag2 locus, which bears a canonical strong binding site and a consensus-deviated weak binding site. Chromatin precipitation assay (Chip) suggests that intracellular NOTCH1 occupies the SPS-containing region in T6E. Mutagenesis of either binding site abrogates NOTCH1-mediated transcriptional activation using the luciferase reporter. In addition, only the expression of dimerization competent NOTCH1 in the HSC derived from RAG1 or RAG2 GFP-reporter mice is able to induce GFP level. Taken together, we have identified two novel NOTCH1 dimer-dependent targets Rag1 and Rag2. These results provide additional examples showing that one conventional and one cryptic CSL binding site can constitute a functional SPS. Together with the observation of gain-of-function NOTCH1 truncations identified in murine T-ALL, our data suggest an important role of NOTCH1-RAG1/2 axis to amplify oncogenic signal strength in murine T-ALL.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3075. doi:1538-7445.AM2012-3075
Abstract 3077: Nek3/Vav2 modulation of the expression of genes involved in breast cancer pathogenesis
Authors: Ratajczak Christine , Clevenger Charles 
Published: August 2012

Abstract
The pituitary hormone prolactin (PRL) is generally recognized for its role in breast growth and differentiation; however, a role for PRL in the pathogenesis of breast cancer has emerged from epidemiological studies and basic science research using both human breast cancer cells and animal models. Activation of the prolactin receptor (PRLr) by PRL contributes to the growth, survival, and motility of human breast cancer cells. PRLr stimulation by PRL results in the activation of multiple signaling complexes including serine/threonine kinase Nek3 and guanine nucleotide exchange factor Vav2. Nek3 is necessary for the activation of Vav2, and Nek3 knockdown results in decreased cytoskeletal re-organization, cell motility, and cell invasion in PRL-stimulated human breast cancer cells. The overexpression of a kinase inactive form of Nek3 in human breast cancer cells results in increased apoptosis, indicating a pro-survival function for Nek3. Furthermore, Nek3 expression is increased in malignant vs. normal human breast tissue. These data make the Nek3/Vav2 complex an interesting target for novel breast cancer therapeutics. To this end, a greater understanding of the role of Nek3/Vav2 in breast cancer pathogenesis is necessary. We hypothesized that the Nek3/Vav2 complex modulates PRL-driven expression of genes involved in the pathogenesis of breast cancer. In these studies, luciferase assays and quantitative PCR were used to evaluate the effects of gain- or loss-of-function of Nek3/Vav2 on the expression of CISH (cytokine-inducible SH2-containing protein). Gain- or loss-of-function of Nek3/Vav2 was found to alter the expression of CISH in response to PRL in both MCF7 and T47D human breast cancer cell lines. The CISH promoter has 4 binding sites for the transcription factor Stat5, which is known to contribute to malignant transformation and tumor growth in breast cancer. Luciferase assay showed that gain- or loss-of-function of Nek3 was also found to alter the activation of a reporter construct containing the lactogenic hormone response element which consists of six tandem Stat5 DNA-binding elements. This suggests that Nek3/Vav2 modulates the PRL-driven expression of CISH by regulating activity of the transcription factor Stat5. Gain- or loss-of-function of Nek3/Vav2 was not found to alter the subcellular localization of Stat5 in response to PRL. Ongoing studies are examining the mechanism of Nek3/Vav2 modulation of PRL-responsive gene expression in breast cancer cells.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3077. doi:1538-7445.AM2012-3077
Abstract 3078: Effects of neuregulins in the regulation of EGFR in breast cancer cell lines
Authors: Kuilan-Torres Laurimer , Perez-Torres Marianela 
Published: August 2012

Abstract
The epidermal growth factor receptor (EGFR) is a member of the ERBB family of oncoproteins which consist of four related receptors: EGFR/ErbB1, ErbB2, ErbB3 and ErbB4. Overexpression of EGFR and other members of ERBB family were found to induce erroneous development and unrestricted proliferation in human malignancies including breast cancer. Neuregulins (NRG) are signaling proteins that produce cell-cell interactions and can bind to the extracellular domain of ErbB3 or ErbB4, activating signaling pathways leading to cellular responses that include stimulation or inhibition of proliferation, apoptosis, and gene regulation. Previous studies showed that constitutive expression of neuregulin 1-beta (NRG-1α) in MCF-7 cells decreased the levels of estrogen receptor (ER) and progesterone receptor (PR), which may contribute to the transformation from estrogen-responsive into a hormone-independent phenotype. An inverse correlation between expression of ER and EGFR has been demonstrated. Our hypothesis is that EGFR levels are regulated by neuregulins in breast cancer cell lines. We treated the breast cancer cell lines ZR-75-1 and MDA-MB-231 with NRG-1α or NRG-1α at different concentrations for 4 hours. In addition, both cells lines were treated with selected concentrations of NRG-1α or NRG-1α at different time points. Isolated mRNA was used to measure EGFR expression using reverse-transcriptase real-time PCR and levels of protein were determined by western blot analysis. Our results show that EGFR mRNA levels increased when ZR-75-1 cells were treated with increasing concentrations of neuregulins. In this regard, treatment with 100 ng/mL of NRG-1α increased EGFR expression by 10-fold in ZR-75-1 cells. However, when MDA-MB-231 cells were treated with NRG-1α or NRG-1α, the expression of EGFR mRNA levels did not change. Western blots analysis of ZR-75-1 cells treated with NRG-1α shows activated ErbB3, confirming that this activation is related to the increase in EGFR mRNA levels. Our data suggest a role for neuregulins in the EGFR up-regulation. One of the mechanisms related to ErbB3 activation is the activation of phosphatidylinositol 3-kinases (PI3K) and mitogen-activated protein kinase (MAPK), thus current efforts are directed towards elucidating the role of these pathways in the NRG-upregulation of EGFR. Supported by NIH/NIGMS Grant #SC2GM084789, NIH-RCMI Grant #G12 RR 03051.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3078. doi:1538-7445.AM2012-3078
Abstract 3080: MYC antagonizes imatinib-induced differentiation in chronic myeloid leukemia cells through downregulation of p27KIP1
Authors: Leon Javier , Gomez-Casares M. Teresa , Ferrandiz Nuria , Lopez Carmen E. , Garcia-Alegria Eva , Albajar Marta , Vaque Jose P , Bretones Gabriel , Delgado M. Dolores 
Published: August 2012

Abstract
Imatinib is a BCR-ABL kinase inhibitor and the most used drug in chronic myeloid leukemia (CML). MYC (c-Myc) is a transcription factor frequently deregulated in human cancer that exerts multiple biological activities, including differentiation inhibition. We found that MYC expression is higher in bone marrow cells form CML patients at diagnosis, as compared with healthy controls. Moreover, high MYC levels at diagnosis correlated with a poorer response to imatinib treatment. One of the major characteristics of CML progression is the loss of cell differentiation. We showed that low concentrations of imatinib induce erythroid differentiation in the CML-derived K562 cell line. We have studied the effect of MYC on the differentiation induced by imatinib using K562 sublines carrying inducible (by zinc cation) or activable (by 4-hydoxy-tamoxifen) MYC alleles. In both cell lines, MYC largely prevented the erythroid differentiation induced by imatinib. The differentiation inhibition mediated by MYC is not due to increased proliferation of MYC-expressing cells or enhanced apoptosis of differentiated cells in the presence of MYC. We previously reported that p27/Kip1 (p27) overexpression induces erythroid differentiation in K562. Thus, we explored the effect of imatinib on p27 levels and we found that imatinib up-regulated p27 in a time- and concentration-dependent manner. siRNA-mediated silencing of p27 antagonized the erythroid differentiation induced by imatinib, indicating that p27 up-regulation is at least in part responsible for differentiation. MYC abrogated the imatinib-induced up-regulation of p27KIP1 concomitantly with the differentiation inhibition, suggesting that MYC inhibits imatinib-mediated differentiation of K562 cells by antagonizing p27 up-regulation. We previously reported that MYC induced SKP2, a component of the ubiquitin ligase complex that targets p27 for degradation. MYC was able to induce SKP2 in the presence of imatinib. Thus, MYC-mediated inhibition of the differentiating effect of imatinib in CML cells is in part a consequence of the SKP2 induction of MYC, which in turn would down-regulate p27. The results suggest that, although MYC deregulation does not directly confer resistance to imatinib, it might be a factor that contributes to progression of CML through the inhibition of differentiation.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3080. doi:1538-7445.AM2012-3080
Abstract 3081: Crosstalk between Runx2 regulatory network and PI3K/Akt signaling pathway in breast cancer cells
Authors: Tandon Manish , Chen Zujian , Pratap Jitesh 
Published: August 2012

Abstract
The Runt-related transcription factor Runx2 is essential for skeletal development but is also aberrantly expressed in several cancers (e.g., breast, prostate and osteosarcoma) where it promotes cell migration, invasive and growth properties of cancer cells. The phosphatidylinositol 3′ kinase (PI3K)/Akt signaling pathway is linked to Runx2-dependent skeletogenesis, however, the mechanisms of Runx2 role in PI3K-Akt signaling in breast cancers, and its implication in cancer progression remains under investigated. To mechanistically determine the function of Runx2 in epidermal growth factor (EGF)-induced PI3K/Akt signaling and concomitantly ensuing downstream signaling events, we modulated Runx2 expression levels in immortalized normal MCF-10A and invasive MDA-MB-231 cells via lentiviral vector-mediated gene delivery. The Runx2 over-expression in EGF-stimulated MCF-10A cells increased the cellular response towards PI3K inhibitor LY294002 as indicated by a decline in Akt (Serine 473) phosphorylation (pAkt) levels. This effect could be restored by Runx2 suppression indicating the specificity of Runx2 function in Akt regulation. In MDA-MB-231 cells, Runx2 over-expression and, surprisingly, suppression profoundly inhibited pAkt suggesting that a threshold level of Runx2 is required for phosphorylation of Akt. The Runx2-mediated decline in pAkt was completely reversed by the Runx2-DNA binding mutant over-expression indicating that Runx2 DNA binding domain is essential for Akt inhibition. To further dissect the mechanism of Runx2-mediated regulation of pAkt levels in MDA-MB-231 cells, we examined the protein levels of phosphatases and kinases associated with PI3K/Akt signaling pathway. These analyses revealed that PH domain and leucine rich repeat protein phosphatase 1 (PHLPP1) levels were directly responsive to Runx2. Chromatin immunoprecipitation studies showed Runx2 recruitment on the proximal promoter of PHLPP1 suggesting that Runx2 mediates its effect on Akt activity, in part by regulating PHLPP1 expression. Furthermore, Runx2 overexpression increased nuclear translocation of a forkhead box transcription factor FoxO1, a downstream molecule of PI3K/Akt signaling indicating an indirect Runx2 affect on FoxO1 transcriptional activity in MDA-MB-231 cells as examined by western blot analysis and immunofluorescence studies. Together, our results identified clinically relevant and novel mechanisms of Runx2 regulatory network in PI3K/Akt signaling pathway that could have important consequences in targeting breast cancer-associated cell survival and invasive properties.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3081. doi:1538-7445.AM2012-3081