bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2853: Sunitinib induces anti-angiogenic splice-variant VEGF165b through induction of CLK1 and CLK4 kinases in prostate cell line DU-145
Authors: Monks Anne , Hose Curtis D. , Doroshow James H. 
Published: June 2012

Abstract
Sunitinib is an oral anti-tumor agent active in renal carcinoma and GIST, which inhibits specific receptor tyrosine kinases that includes targeting vascular endothelial growth factor receptors (VEGFR). To understand mechanisms which may drive this agent's activity, transcriptional profiling (GeneChip® HT Human Genome U133 Array Plate Set) of the NCI-60 human tumor cell lines treated with 200 and 2000 nM sunitinib was completed. Examination of the data indicated the CDC2-like genes, CLK1 and CLK4, were upregulated in multiple cell lines after 2 h drug incubation, with a decreasing level of expression over 6 and 24 h. These kinases are implicated in regulation of alternative splicing of mRNA and may favor selection of the distal splice site of exon 8 in the VEGFA gene. These splice variants of VEGFA are designated VEGFAxxxb and have been shown to have anti-angiogenic properties; regulation of this form of alternative splicing has been identified as a potential novel strategy for anti-angiogenic therapeutics. To confirm whether sunitinib-induced CLK1 and CLK4 expression was indicative of a change in the splice variants of VEGFA, specific primers were used in TaqMan® Q-RT/PCR to distinguish the exon 8 distal splice variant VEGFA165b (anti-angiogenic) from the proximal splice variant VEGFA165a (pro-angiogenic) of the dominant mRNA isoform, VEGFA165. VEGFA165b variant gene expression was induced 2-4 fold over 24h, compared to &lt; 2-fold change in the VEGFA165a expression in 2 cell lines (DU-145 and NCI-H322M) with robust sunitinib-induced CLK1 and 4 expression compared to no change in VEGFA165b expression in a cell line with no increase in CLK1 and 4 after sunitinib treatment. Using DU-145 cells, we also demonstrated a sunitinib-induced, 2-fold increase in VEGFA165b protein expression over 24 h. Inhibition of CLK 1 and 4 kinases with a specific CLK inhibitor, TG003, decreased constitutive gene expression of VEGFA165b in DU-145, indicating the importance of the CLK genes in regulating distal splice variants of the VEGFA165 mRNA isoform. In combination with sunitinib, CLK inhibition by TG003, prevented sunitinib-induced upregulation of the VEGFA165b splice variant. Thus we have uncovered a novel mechanism underlying the activity of the VEGFR inhibitor, sunitinib, where induction of CLK kinases change the balance of VEGFA splice variants towards expression of anti-angiogenic species through which modulation of angiogenesis may occur. Funded by NCI Contract No. HHSN261200800001E.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2853. doi:10.1158/1538-7445.AM2011-2853
Abstract 2854: Delineation of grade-specific molecular drivers in inducible preclinical mouse models of astrocytoma
Authors: Song Yurong , Zhang Qian , Bash Ryan , Yin Chaoying , Yang Chunyu , Gilbert Debra , Wang Sophie , Bullitt Elizabeth , Kafri Tal , McCarthy Ken D. , Louis David N. , Miller C. Ryan , Van Dyke Terry 
Published: June 2012

Abstract
Glioblastoma (GBM) is a uniformly lethal neoplasm that accounts for 20% of all primary brain tumors. Despite advances in multimodality therapy, the median survival for patients with this disease remains approximately 12 months and has changed little over the past 40 years. An increased understanding of the molecular genetic basis of gliomagenesis is urgently required to develop more effective therapies for this devastating disease. Recently, The Cancer Genome Atlas (TCGA) project reported the most extensive genetic analysis of GBMs enhancing our ability to query altered signaling pathways potentially involved. Yet, an understanding of disease etiology requires extensive modeling in mammalian genetic systems coupled with analyses of biological contributions of disease. Here we genetically perturbed the primary molecular pathways (pRb and Ras) in genetically engineered mouse models (GEM). Alterations were induced specifically in adult GEM astrocytes via a tamoxifen-inducible, human GFAP promoter-driven CreERTM allele. GEM with astrocyte RB pathway inactivation alone (T) developed low-grade astrocytomas (grade II). Constitutive KRAS activation alone (R) did not produce detectable brain pathology. GEM harboring both inactivated RB and constitutively active KRAS (TR) in astrocytes developed high-grade astrocytomas (grade III) with low frequency of GBM development (grade IV). Deletion of Pten further progressed the tumor to grade IV with high frequency. Mechanistically, pRb inactivation led to activation of MAPK pathway via Ras. Mutant Kras did not further activate MAPK. Instead, it activated PI3K pathway. Deletion of Pten further activated PI3K-AKT pathway, leading to higher GBM rate. These highly penetrant, inducible GEM models provide a unique system for delineating the downstream pathways and resulting biological abnormalities critical to astrocytoma pathogenesis and for preclinical drug and biomarker development. Initial studies have begun to define the relative contribution to disease of each disrupted pathway, including potential targets for therapeutic intervention.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2854. doi:10.1158/1538-7445.AM2011-2854
Abstract 2859: Identification of driver mutations in colon cancer using Sleeping Beauty mutagenesis
Authors: Starr Timothy K. , Allaei Raha , Sarver Aaron , Silverstein Kevin , O'Sullivan M. Gerard , Cormier Robert , Largaespada David 
Published: June 2012

Abstract
Human colon tumors contain hundreds of genetic and epigenetic anomalies, of which only a handful are responsible for the growth and development of the tumor. We have developed a forward genetic screen in mice that can identify those mutations capable of causing gastrointestinal tract tumors. By comparing the mutations identified in our screen with those found in human colon tumors we can pinpoint the drivers of carcinogenesis. The forward genetic screen uses the Sleeping Beauty (SB) DNA transposon as a random mutagen capable of both activating and inactivating genes. Using Cre recombinase under the control of the Villin promoter we can selectively activate this mutagenesis in intestinal epithelial cells in the mouse. Tumors generated in these mice are analyzed for transposon insertion sites using linker mediated-PCR in combination with high-throughput sequencing. This analysis provides us with genomic sequence that can be mapped to the mouse genome. Candidate cancer driver genes are identified because they are located in areas of the genome that are recurrently mutated by the SB transposon in multiple tumors.
We conducted the screen in wild-type mice and identified 77 candidate cancer genes, of which six were previously known human colon cancer genes (APC, BMPR1A, SMAD4, PTEN, FBXW7, CDK8). More importantly, we identified many novel candidate drivers that can now serve as potential targets in colon cancer therapy. We have extended our studies by conducting three more screens using mice that already contain a known driver mutation. The purpose of these new screens is to gain a better understanding of the genetic changes that cooperate with common mutations found in colon cancer. The three screens used mice that have a mutation in Apc (ApcMin), carry a dominant negative acting Trp53 (p53R270H), or are null for the tumor suppressor gene p19ARF. We have completed the screen in ApcMin mice and found an additional 30 candidate drivers of colon cancer that may specifically cooperate with the Apc mutation. The two final screens are in the process of completion and should uncover genes that cooperate with mutations in Trp53 and p19ARF. The results of these studies will greatly expand the list of potential therapeutic targets and will enhance our understanding of the genetic etiology of colon cancer.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2859. doi:10.1158/1538-7445.AM2011-2859
Abstract 2882: CREB inhibition attenuates MM tumor growth and drug resistance
Authors: Shukla Arti , Hillegass Jedd M. , Macpherson Maximilian B. , Beuschel Stacie L. , Steele Chad , Mossman Brooke T. 
Published: June 2012

Abstract
Malignant mesothelioma (MM) has a poor prognosis because of its difficult diagnosis and chemoresistance. We have shown previously that cyclic AMP response element binding protein (CREB) is constitutively activated (phosphorylated) in MM cells and tissue arrays as compared to mesothelial cells or benign lesions. Moreover, inhibition of CREB results in increased Doxorubicin (Dox)-induced apoptosis by attenuation of prosurvival genes, Bcl2 and BclxL. Using intraperitoneal and subcutaneous SCID xenograft mice models injected with shCREB (CREB inhibited) human MM cells (Hmeso), we show that CREB inhibition significantly attenuates tumor growth in both models. In addition, CREB inhibition also results in additional decreases in tumor size after treatment with Dox (0.5mg/kg, ip, 3 times a wk for 6 wks), suggesting a role of CREB in drug resistance. TUNEL staining on tumor sections showed increased cell death in CREB-inhibited tumors. Assessment of human cytokine levels by Bioplex analysis in peritoneal lavage fluid (PLF) of tumor-bearing mice showed that CREB inhibition significantly attenuated levels of IL-6, IL-8, VEGF, MCP1, IFN-gamma, IP-10 and RANTES. Dox treatment per se increased levels of several cytokines (IL-6, IL-8, G-CSF, IP-10, MIP-1B, RANTES), however, in the presence of shCREB, these levels were significantly decreased after Dox treatment. Other cytokine levels like bFGF, IFN-gamma, MCP1 and VEGF were reduced following Dox treatment, and further decreases were observed in CREB inhibited (shCREB) tumors. Microarray analysis performed on shCREB-Hmeso cells in vitro showed several fold decreases in various tumorigenesis- related genes including PAK7, Calbindin 1, TIE-2, MCAM, CD24, CCL-5, c-Met, v-kit, MMP2, IL-6, and snail homolog 2 as compared to shControl-Hmeso cells. In addition, increases in mRNA levels of phosphatases, Dachund homolog, and Caspase-1 were also observed following CREB inhibition. The patterns of gene expression and cytokine release by shCREB suggest that CREB affects tumor growth by regulating proliferation/survival, angiogenesis, migration and apoptosis. In addition, we also show that inhibition of CREB expression renders MM tumors more susceptible to Dox. This study is supported by National Cancer Institute grant PO1CA114047 and a grant from the Vermont Genetics Network (VGN).
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2882. doi:10.1158/1538-7445.AM2011-2882
Abstract 2894: Co-regulatory relationship between estrogen receptor alpha and the mTOR/S6K1 signaling pathways
Authors: Holz Marina K. , Maruani D. Myriam , Seligman Fannie , Spiegel Tirtza , Harris Emily , Shachter Avielle , Beren Faygel 
Published: June 2012

Abstract
ERα mediates the proliferative effects of estrogen and represents an important clinical target in treatment of breast cancer. Tamoxifen is an anti-estrogen that has become the standard agent for the treatment of ER-positive breast cancer, where it acts as an antagonist. However, resistance to tamoxifen, and other endocrine or anti-estrogen therapies develops in many cases. One mechanism by which resistance develops is through phosphorylation of ERα, allowing it to act in estrogen-independent manner. Phosphorylation of Ser118 and Ser167 is important for transcriptional activity of ERα. The regulation of these sites is complex, involving inputs from the mTOR and MAPK signaling pathways. Importantly, ERα phosphorylation correlates with resistance to tamoxifen, and is a prognostic marker for disease progression and survival. Thus, the mechanism of these phosphorylation events, as well as the identity of the kinases responsible may have important clinical consequences. In this study we demonstrate that the mTOR/S6K1 pathway controls activation of ERα by phopshorylating it on these two critical residues.
Chromosomal region 17q23 containing the RPS6KB1 gene is frequently amplified in breast cancer cells, and S6K1 is overexpressed in about 30% of cases. Overexpression of S6K1 correlates with increased rapamycin sensitivity. The role of S6K1 in disease development and progression is supported by the observation that S6K1 overexpression is associated with poor prognosis in breast cancer patients. However, the reason for high-level amplification of the RPS6KB1 gene specifically in breast cancer, and not other cancer types is not well understood. In this study, we demonstrate that in response to estrogen activation, ERα activates expression of S6K1 by upregulating transcription of the RPS6KB1 gene. Increased levels of S6K1 promote further phosphorylation and activation of ERα, creating a positive feed-forward loop. We hypothesize that this relationship promotes breast cancer cell growth, thus providing a selective advantage to S6K1- and ERα-overexpressing cells.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2894. doi:10.1158/1538-7445.AM2011-2894
Abstract 2896: MEK inhibition controls EGFR level in EGFR-dependent NSCLC cells via deregulated expression of EGF-like ligands
Authors: Milewska Marta , Balko Justin Micah , Black Esther Penni 
Published: June 2012

Abstract
Purpose: The aim of the present study is to investigate the molecular mechanism underlying MEK inhibitor-induced EGFR down-regulation in EGFR-dependent NSCLC cell lines.
Methods: EGFR protein level in A549 and H1975 cell lysates was explored by Western blot assay. A549 and H1975 cell lysates were prepared and separated on SDS-polyacrylamide gels and blotted on PVDF membranes with antibodies specific for total or phosphorylated forms of EGFR, AKT, and total or phosphorylated ERK1/2. Calnexin or α-tubulin was used as loading control. Analysis of EGFR, HB-EGF and TGFα gene expression was performed using quantitative real time PCR (qPCR). Total RNA was extracted from cells and used for cDNA synthesis. qPCR was performed using Taqman On-Demand assays for EGFR, TGFα, HB-EGF and GAPDH. Relative quantification was applied using normalization to GAPDH.
Results: In the present study we observed that activation of the EGFR signaling cascade is attenuated by inhibition of MEK, resulting in down-regulation of EGFR in EGFR-dependent H1975 cells but not in EGFR-independent A549 cells. Interestingly EGFR down-regulation in H1975 cells does not occur at the level of transcription. However, mRNA expression of HB-EGF and TGFα, ligands overexpressed in EGFR-dependent H1975 cell line, decreased when treated with MEK inhibitor (AZD6244, Astra Zeneca). In contrast, no decrease in expression of either of the ligands was observed in the EGFR-independent A549 cell line following AZD6244 treatment. Interrogation of EGFR turnover using both protein degradation inhibitors and neutralizing anti-EGFR and anti-HB-EGF antibodies suggested that MEK inhibition down-regulates EGFR expression by directing EGFR to lysosomal degradation via deregulated EGFR and ligands interactions.
Conclusions: Our results suggest that loss of active ERK1/2 does not directly impact EGFR gene transcription and that MEK inhibition eliminates the signal for EGFR recycling and promotes degradation of EGFR. We assert that the MAPK cascade regulates production of EGF-like ligands responsible for maintaining high levels of active EGFR on which the cells depend. The difference in level of HB-EGF and TGFα ligands observed in EGFR-dependent cells indicates that EGFR signaling in these cells is maintained by both overexpression of ligands and maintenance of active ligands for EGFR interaction. Finally, our findings indicate that targeting EGFR ligand expression via the MAPK pathway may provide therapeutic benefit in EGFR-dependent lung cancer harboring resistant mutation to TKIs.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2896. doi:10.1158/1538-7445.AM2011-2896
Abstract 291: Evaluation of blood flow in hepatocellular carcinoma: Assessment with computed tomography perfusion parameters and circulating angiogenic factors
Authors: Chen Ya-Wen , Chou Chen-Pin 
Published: June 2012

Abstract
Purpose: To study the relationships between CT perfusion parameters and circulating angiogenic factors in patients with hepatocellular carcinoma (HCC)
Materials and Methods: This study was HIPAA compliant and was approved by the institutional review board. All participants provided informed consents. CT perfusion parameters of HCCs among 21 patients were assessed using 21-phase liver images at a 64-slice multidetector CT. We analyzed CT perfusion parameters including total blood flow, arterial blood flow, portal blood flow and arterial fraction (arterial blood flow /total blood flow) of HCCs, surrounding liver parenchyma and HCC-parenchyma ratio. Interleukin 6 (IL-6), interleukin 8 (IL-8), vascular endothelial growth factor (VEGF), and platelet derived growth factor (PDGF) in plasma were measured using Bio-Plex multiplex immunoassay in 21 HCC patients and 8 healthy controls.
Result: CT perfusion parameters of HCCs showed statistically different from that of surrounding liver parenchyma in total blood flow (p=0.002), portal blood flow (p&lt;0.001) and arterial fraction (p&lt;0.001). Circulating IL-6, IL-8 and VEGF showed significantly higher levels in HCC patients than controls (p&lt;0.05), and predicted HCC significantly better than chance (p&lt;0.001). None of circulating angiogenic factors had significant correlation with any of CT perfusion parameters in HCC patients. Only HCC-parenchyma ratio of arterial blood flow showed significant positive correlation with circulating IL-8 (p&lt;0.05).
Conclusion: CT perfusion parameters of HCC and circulating angiogenic factors are useful tools for HCC diagnosis. Only circulating IL-8 and HCC-parenchyma ratio of arterial blood flow showed significant correlation.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 291. doi:10.1158/1538-7445.AM2011-291
Abstract 2920: Estrogen, tamoxifen, and Akt modulate expression of putative housekeeping genes in breast cancer cells
Authors: Shah Khyati Niral , Faridi Jesika S. 
Published: June 2012

Abstract
For quantitative reverse transcription-polymerase chain reaction (RT-qPCR), accurate data normalization requires the use of a stable reference gene. In estrogen-dependent cells, the identification of an appropriate housekeeping gene that is unaltered regardless of experimental conditions has been difficult. Additionally since cross-talk between the estrogen receptor and Akt pathways has been reported, the goal of this study was to identify the most stable reference gene for RT-qPCR (from a panel of nine putative housekeeping genes) that remains unaltered despite estrogen or tamoxifen treatment or stable overexpression of active Akt. Gene expression of nine candidate genes (GAPDH, ACTB, RPL13A, PGK1, TFRC, PPIA, HPRT1, B2M, and GUSB) was determined in parental and Akt overexpressing MCF-7 breast cancer cells treated with estrogen, tamoxifen, or vehicle, and gene stability was analyzed using two different statistical models. We observed that GAPDH, HPRT1, PGK1, and B2M were highly estrogen-regulated in parental MCF-7 cells. We also observed that seven out of the nine candidate genes were significantly altered in at least one of the Akt overexpressing MCF-7 cells. Based on our results, we suggest RPL13A as the most suitable internal reference gene that is both stable and remains unaltered in MCF-7 cells regardless of estrogen or tamoxifen treatment or Akt overexpression. In addition, our work emphasizes the importance of a preliminary study to validate each reference gene that will used for RT-qPCR.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2920. doi:10.1158/1538-7445.AM2011-2920
Abstract 2934: Novel approach for treating neural crest derived tumors: Selective inhibition of ganglioside biosynthesis with small molecules
Authors: Bai Xiaomei , Nguyen Tram , Brown Jillian , Glass Charles A. , Duron Sergio , Bhagwat Shripad S. , Crawford Brett E. 
Published: June 2012

Abstract
Neural crest derived tumors express high levels of a unique class of lipid linked glycan known as gangliosides. Gangliosides are involved in growth factor signaling by regulating complexes in lipid rafts. Genetic studies show that through aberrant expression of gangliosides, these tumors acquire aggressive growth properties. Prior to this research, the only ganglioside inhibitors identified were non-specific and broadly blocked virtually all glycolipid classes. These non-specific glycolipid inhibitors demonstrated anti-cancer activity in animal models of neural crest tumors. However, due to substantial off-target dose-limiting toxicity from lack of specificity for the ganglioside sub-class, they effectively cannot be used in humans for cancer treatment. Selective inhibition of gangliosides without affecting other glycan classes could potentially avoid these problems and provide an effective treatment for neural crest and other ganglioside-dependent tumors. To identify the first known selective inhibitors of gangliosides, we developed a novel molecular screening strategy for identifying selective small-molecule ganglioside inhibitors. This platform identified the first drug-like selective inhibitors of gangliosides. ZP10395, a lead compound, selectively and dose-dependently reduces gangliosides in multiple tumor cell lines and is 10-15 fold more potent than the existing non-specific inhibitors. Importantly, it does not inhibit other glycolipid classes associated with dose-limiting toxicity. Administering ZP10395 to a mouse xenograph melanoma model significantly reduced ganglioside production and slowed tumor growth in the presence of a reduced T-cell response. These results demonstrate the potential utility of specific ganglioside inhibitors for treating ganglioside dependent tumors.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2934. doi:10.1158/1538-7445.AM2011-2934