bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3822: DNA copy number changes in the PI3K signaling pathway genes in triple negative breast cancer
Authors: Oliveira Marcia C. , Pereira Silma R. , Ribeiro Enilze MF , Lima Rubens S. , Urban Cicero A. , Sebastião Ana Paula M. , Marian Catalin , Haddad Bassem R. , Cavalli Iglenir J. , Cavalli Luciane R.
Published: June 2012

Background: Triple negative breast cancer (TNBC) is associated with poor prognosis and a high mortality rate when compared to the other breast cancer subtypes. These tumors lack the expression of ER, PR and HER2 receptors, and do not respond well to the currently available adjuvant therapies. The phosphatidylinositol 3-kinase (PIK3) signaling pathway mediates key cellular functions. Alterations of genes in this pathway have been shown to predict responsiveness to cancer targeted therapies. In this study, five genes involved in this signaling pathway, PIK3CA, AKT1, AKT2, PTEN and FGFR, were evaluated for DNA copy number changes in two sets of TNBC specimens.

Methods: TNBC samples were obtained from the Hospital Nossa Senhora das Gracas, Curitiba, PR, Brazil. Two sets of TNBC samples were analyzed: the first set was composed of 30 formalin fixed-paraffin embedded tissue specimens and were analyzed for the PIK3CA, AKT1, AKT2, PTEN and FGFR genes by FISH. Locus-specific probes were prepared from BAC contigs for each gene and a centromeric probe for chromosome 3 was used as a control for copy number. The second set was composed of 17 frozen samples and were analyzed by array-CGH using a 44K-Agilent array platform. Real-Time PCR (TaqMan assay), was used to validate the array-CGH data for the above five genes.

Results:

FISH: PTEN loss and FGFR3 amplification were the most common findings occurring in 56% and 41% of the TNBC samples respectively. PIK3CA, AKT2 and AKT1 were amplified in 31%, 25% and 9.5% of the samples respectively.

Array-CGH/Real time PCR: DNA copy number changes were observed by array-CGH in all, but one TNBC sample. The gene with highest frequency of amplification detected by array-CGH was PIK3CA (amplified in 77% of the cases). These findings were confirmed in 70% of the cases. FGFR2, AKT2 and PTEN were amplified in 35%, 24% and 24% of the cases respectively, These findings were confirmed for FGFR2 in 83% of the samples and for PTEN in all the samples. AKT2 amplification was only confirmed in 25% of the samples. Finally AKT1 was observed amplified in by array-CGH in 6% of the cases, which was confirmed by Real-time PCR.Conclusions: Based on our initial results, we conclude that TNBC presents DNA copy number alterations in genes involved in the PIK3 signaling pathway. Upon validation of these alterations in a larger number of cases, with correlation to prognostic parameters, their potential use as therapeutic targets can be considered for further investigation.

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 3822. doi:10.1158/1538-7445.AM2011-3822
Abstract 3834: 3-ethynyl-1H-indazoles as inhibitors of PI3k signaling pathway
Authors: Barile Elisa , De Surya , Carlson Coby B. , Chen Vida , Knutzen Christine , Riel-Mehan Megan , Dahl Russell , Chiang Gary , Pellecchia Maurizio
Published: June 2012

A new series of 3-ethynyl-1H-indazoles has been synthesized and evaluated in both biochemical and cell-based assays as potential kinase inhibitors. Interestingly, a selected group of compounds identified from this series exhibited low micromolar inhibition against critical components of the PI3K pathway, targeting PI3K, PDK1 and mTOR kinases. Combination of computational modeling and structure-activity relationships studies reveal a possible novel mode for PI3K inhibition, resulting in a PI3Kα isoform specific compound. Hence, by targeting the most oncogenic mutant isoform of PI3K, the compound displays anti-proliferative activity both in monolayer human cancer cell cultures and in three-dimensional tumor models. Because of its favorable physicochemical, in vitro ADME and drug-like properties, we propose that this novel ATP mimetic scaffold could result useful in deriving novel selecting and multi-kinase inhibitors for clinical use.

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 3834. doi:10.1158/1538-7445.AM2011-3834
Abstract 3839: Wild-type p53 induced protein phosphatase (Wip1) inhibits the proapoptotic function of JNK and p38 MAPK in prostate cancer cells
Authors: Song Ji Young , Young Park Ji , Hye Kim Ga , Choi Jene
Published: June 2012

The mechanism regulating radiation-induced anti-apoptotic response in prostate cancer cell lines is not clear yet. Wip1 is the major member of the Ser/Thr PP2C family that dephosphorylates and inactivates p38 MAPK, p53, chk1, Mdm2 and ATM. Here we provide Wip1 was negative regulator of γ-radiation-mediated apoptotic response in LNCaP cells. The levels of Wip1 were increased after exposed to γ-radiation and induced Wip1 repressed cell death. Wip1 depletion with siRNA resulted in increased apoptotic cell death in LNCaP cells, which was not observed in radiation-sensitive HeLa cells. Radiation-induced Wip1 induction was inversely co-related with the decrease of phospho-JNK and -p38 MAPK in LNCaP cells, indicating that Wip1 is a negative regulator of JNK and p38 MAPK pathways. Furthermore, in response to γ-radiation, Bax proteins are increased and directly interact with Wip1. The data suggest that Wip1 may be a central player on the mechanism of radio-resistance in LNCaP cells. Currently, we are investigating the role of Wip1 in BAX-mediated apoptotic cell death.

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 3839. doi:10.1158/1538-7445.AM2011-3839
Abstract 3840: Rap1 GTPase activating protein (Rap1GAP) is downregulated in DCIS and invasive ductal carcinoma
Authors: Rhee Sarah S. , Lim Bora , Kim Hyoung-ha , Wang Yan , Aziz Usman , Butt Usman , Tang Waixing , Vuchak Lisa A. , DeMichele Angela , Troxel Andrea B. , Feldman Michael D. , Meinkoth Judy L. , Brose Marcia S.
Published: June 2012

Introduction: Rap1 and Rap2, both small GTPases of the Ras family, serve as crucial regulators in cell polarity, adhesion, migration, and lumen formation via crosstalk with cytoskeletal proteins. Rap1 GTPase activating protein (Rap1GAP), which negatively regulates Rap1 and Rap2 activity, has found to be downregulated in multiple cancers, including oropharyngeal squamous cell carcinoma, melanoma, papillary and follicular thyroid carcinoma, and colorectal carcinoma but has not yet been studied in breast cancer. In order to determine if Rap1GAP downregulation plays a role in breast cancer formation, we decided to expand our prior work to study its expression in breast cancer tissue.

Methods: Twenty-one formalin-fixed paraffin-embedded human tissue blocks were selected on the basis that they contained normal breast tissue and either adjacent breast ductal carcinoma in situ (DCIS) or invasive ductal carcinoma. Using immunohistochemistry, we assessed the expression of Rap1GAP. We also assayed two human breast cancer cell lines with different levels of invasiveness, MCF7 (non-invasive) and MDA-MB-231 (invasive), to determine different levels of Rap1GAP expression and subsequent changes in Rap1 and Rap2 expression and activity.

Results: Rap1GAP expression in both DCIS and invasive ductal carcinoma were found to be decreased compared to adjacent normal breast tissue. However, Rap1GAP expression was not statistically different between DCIS and invasive carcinoma lesions. Rap1GAP was found to be expressed highly in MCF7 but not in MDA-MB-231 cells. Moreover, only MDA-MB-231 cells exhibited high basal Rap2 activity. Activated Rap1 (RAP1-GTP) was not detected in either line.

Conclusion: Our findings suggest that loss of Rap1GAP occurs as an early event in breast cancer tumorigenesis with a significant decrease in the transition from normal to DCIS, with a possible further decrement in the DCIS to invasive transition. Interestingly, while Rap1 and Rap2 were expressed in non-invasive and invasive cell lines, loss of Rap1GAP in the invasive cell line was associated with increase in active Rap2, but not active Rap1. These findings suggest that as in other cancers, loss of Rap1GAP may contribute to the invasive phenotype and thus further investigation is warranted.

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 3840. doi:10.1158/1538-7445.AM2011-3840
Abstract 3850: CDKN2a deficiency exposes a requirement for RhoA in maintenance of non-small cell lung cancer
Authors: Konstantinidou Georgia , Torti Francesca , Batten Kimberly , Minna John D. , Shay Jerry W. , Scaglioni Pier Paolo
Published: June 2012

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related death world-wide. Tumorigenesis is a multistep process that involves several genetic aberrations. For example, K-RAS (onc-K-RAS), the most commonly mutated oncogene in human cancer, is expressed in about 25% of NSCLC. In addition, NSCLC often carry mutations or epigenetic modifications that affect the expression of the CDKN2a locus, which comprises the p16INK4a and the p14ARF (p19ARF in mice) tumor suppressor genes, which in turn regulate the retinoblastoma and the p53 tumor suppressor pathways.

NSCLC tumorigenesis is faithfully recapitulated in transgenic mice where onc-K-Ras expression invariably induces adenomas and, after a long latency, adenocarcinomas. To characterize the consequence of concomitant onc-K-RAS expression and CDKN2a inactivation, we generated p16CDK4/p19ARF null mice expressing onc-K-Ras in the respiratory epithelium.

We determined that Cdkn2a deficiency promotes rapid progression of lung adenomas to adenocarcinomas, which display aggressive features. We determined the status of activation of oncogenic signaling networks downstream of onc-K-Ras with phosphospecific antibodies and by expression profiling. We discovered that NSCLC that arises in CDKN2A deficient mice display dysregulation of RhoA, a small GTPase implicated in the regulation of the cytoskeleton, cell adhesion, and motility of cancer cells in culture. These activities are pertinent to tumorigenesis, however it is not known whether RhoA plays a role in the maintenance of established tumors.

Surprisingly, we determined that RhoA is required for the survival of NSCLC derived lines expressing onc-K-RAS and deficient for either INK4a or the p53 tumor suppressor both when cultured in vitro and as xenografts in vivo. Cell death was due to a proapoptotic program and was accompanied by disruption of the cytoskeleton. Moreover, by performing loss and gain of function experiments we identified focal adhesion kinase (FAK) protein as the principal downstream target of RhoA responsible for this effect. Experiments in vivo with specific inhibitors are ongoing and will be presented at the meeting.

Our findings reveal a previously unappreciated context dependent requirement of the RhoGTPase to maintain viability of established NSCLC. We propose that RhoA and its signaling network are novel therapeutic targets in NSCLC.

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 3850. doi:10.1158/1538-7445.AM2011-3850
Abstract 3851: The nuclear guanine nucleotide exchange factors Ect2 and Net1 regulate RhoB-mediated cell death after DNA damage
Authors: Srougi Melissa C. , Burridge Keith
Published: June 2012

Commonly used antitumor treatments, including radiation and chemotherapy, function by damaging the DNA of rapidly proliferating cells. However, resistance to these agents is a predominant clinical problem. A member of the Rho family of small GTPases, RhoB has been shown to be integral in mediating cell death after ionizing radiation (IR) or other DNA damaging agents in Ras-transformed cell lines. In addition, RhoB protein expression increases after genotoxic stress, and loss of RhoB expression causes radio- and chemotherapeutic resistance. However, the signaling pathways that govern RhoB-induced cell death after DNA damage remain enigmatic. Here, we show that RhoB activity increases in human breast and cervical cancer cell lines after treatment with DNA damaging agents. Furthermore, RhoB activity is necessary for DNA damage-induced cell death, as the stable loss of RhoB protein expression using shRNA partially protects cells and prevents the phosphorylation of c-Jun N-terminal kinases (JNKs) and the induction of the pro-apoptotic protein Bim after IR. The increase in RhoB activity after genotoxic stress is associated with increased activity of the nuclear guanine nucleotide exchange factors (GEFs), Ect2 and Net1, but not the cytoplasmic GEFs p115 RhoGEF or Vav2. Importantly, loss of Ect2 and Net1 via siRNA-mediated protein knock-down inhibited IR-induced increases in RhoB activity, reduced apoptotic signaling events, and protected cells from IR-induced cell death. Collectively, these data suggest a mechanism involving the nuclear GEFs Ect2 and Net1 for activating RhoB after genotoxic stress, thereby facilitating cell death after treatment with DNA damaging agents.

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 3851. doi:10.1158/1538-7445.AM2011-3851
Abstract 3863: Exhaled microRNAs as potential biomarkers in lung cancer
Authors: Shi Miao , Han Weiguo , Spivack Simon
Published: June 2012

Introduction: There is a need for non-invasive airway-based biomarkers in lung carcinogenesis for both diagnosis, and risk assessment. MicroRNAs are small, stable, noncoding RNAs that function in gene regulation. Recent studies have revealed that microRNAs play important regulatory roles in carcinogenesis. Exhaled breath condensate (EBC) contains airway lining fluid molecules, including nucleic acids, as we've previously reported for DNA methylation. We previously developed an RNA-specific microRNA-PCR, whereby PCR artifact can be detected. Here we pilot the detection of microRNAs in EBC of lung cancer patients and controls. Methods: MicroRNA expression profiling using RNA-specific RT-qPCR was performed in EBC from 28 subjects, choosing literature-derived microRNAs that segregate tumors and non-tumor tissue, and an ongoing discovery effort we have commenced using microRNA-seq for tumor versus non-tumor comparison. As of abstract deadline, the top 12 significantly different microRNAs between lung tumor and non-tumor were chosen and their qPCR primers were designed. Results: So far, we have detected several microRNAs in EBC including 21, 34a, 153, 193b, 200c, 221; case-control comparisons are pending. Topographic validation studies are pending. Conclusion: By comparing the differences of microRNA expression between EBC from lung cancer cases and EBC from non-cancer controls, potential exhaled microRNA biomarkers might be found and used in early detection of lung cancer.

This work was supported by National Institutes of Health grants1RC1 CA145422-01, 1K24-CA139054-01.

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 3863. doi:10.1158/1538-7445.AM2011-3863
Abstract 3870: Improved PCR amplification of DNA biomarkers with the use of chimeric oligonucleotides
Authors: Millholland John M. , Patel Sheryl G. , Shuber Anthony P.
Published: June 2012

Methylation of the Twist1 gene has been linked to various cancers, including bladder cancer. We are developing a non-invasive diagnostic assay utilizing urinary protein and DNA biomarkers, including Twist1, as triage monitors in high-risk bladder cancer populations. Since final clinical assay performance is dependent on the optimal technical performance of each individual marker, we incorporated the use of chimeric PCR primers to establish PCR conditions for all DNA markers that would greatly simplify the process of optimizing PCR performance.

Amplification of difficult DNA templates can involve significant optimization of PCR conditions, and is often complicated by mispriming and other non-specific amplification events. The chimeric primers we designed have a variable 3’ target-specific sequence, and a common 22 nucleotide 5’ sequence that is unrelated to any human DNA. The common 5’ sequence generates similar melting temperatures for all primers (Tm 68-72oC) that permits uniform PCR conditions regardless of the characteristics of the template specific sequence. In addition, the chimeric primers permit a higher annealing temperature, which minimizes non-specific PCR amplification.

In the study described here, conventional methylation specific primers were designed against a highly methylated region of the Twist1 promoter with and without the 5’ chimeric DNA sequence, and PCR conditions were optimized for each primer pair. Performance was assessed using DNA isolated from 50 bladder cancer tissues. After bisulfite conversion, PCR amplifications were carried out using the Bio-Rad C1000 platform and subsequently analyzed by agarose gel electrophoresis. Using traditional primers, Twist1 sensitivity was comparable to previous reports (68%, Renard et al, 2010), whereas using the chimeric primers, sensitivity increased to 90%.

Incorporation of chimeric primers greatly simplifies PCR optimization and permits the use of higher annealing temperatures, resulting in higher specificity. We have applied this method to the detection of Twist1 methylation in bladder cancer tissues and demonstrate significant improvement in performance, when compared to traditional, non-chimeric oligonucleotide primers. In addition, this primer modification can be applied to multiple assay formats and DNA targets to improve sensitivity for use in non-invasive diagnostic assays, where mutant DNA is expected to be limiting.

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 3870. doi:10.1158/1538-7445.AM2011-3870
Abstract 3871: Expression of MACC1, a metastasis-related protein, associated with the progression of colorectal cancer
Authors: Ashktorab Hassan , Herrmann Pia , Lee Edward L. , Razjouan Hadi , Green William , Smoot Duane T. , Brim Hassan , Stein Ulrike
Published: June 2012

Background: Colorectal cancer (CRC) as the second most common cancer in western world has different prognostic basis in contrast to other cancers. Its pathologic staging is the main prognostic factor. Recently, MACC1 has been proposed as an effective marker for identifying patients at high risk for the development of distant metastases when MACC1 is highly expressed in the not (yet) metastasized primary tumor.

Aims and Methods: We aimed to assess the cellular and sub-cellular expression of MACC1 in age matched normal, adenomatous and cancerous colonic tissue samples. Samples were recruited from pathology department of Howard University Hospital. The Tissue Micro Array (TMA) sections were made from all duplicated samples and put in three different TMA slides as normal matched (n=44), adenomatous (n=60) and adenocarcinoma (n=36). Total of 140 samples were stained for MACC1 by Immuno-Histo-Chemistry method. Then, all three TMA were read by two pathologists including one GI pathologist. The expression were reported as staining 0, 1, 2, 3, 4 which refer to none, less than 10%, 10-25%, 25-50%, 50-75%, >75%, respectively. Sub-cellular staining was reported as nuclear, cytoplasmic, or both.

Results: Of 140 samples, 36 were adenocarcinomas (mean age: 64.3; M/F: 16/20); 60 adenomatous (mean age: 64.8; M/F: 31/29); 44 normal controls (mean age 65.8; M/F: 22/22). Adenocarcinomas received score 4 in 86.1% of cases which was significantly higher (p<0.05) than normal (15.9%) and adenomatous (28.3%) cases. MACC1 stained more in cytoplasm (88.6%) in contrast to normal (44.7%) and adenomatous cases (32.1%) with P < 0.05. Observationally, high grade adenomas had higher scores (3 or 4) than low grade ones (P=0.1). Of total 18 patients with stage 3 and/or 4, 14 scored 4 and had cytoplasmic stainning.

Conclusions: Our data showed that MACC1 not only can be a prognostic and pathological marker to differentiate high grade from low grade adenoma.

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 3871. doi:10.1158/1538-7445.AM2011-3871
Abstract 39: A mathematical model for the dependence on tumor size of the rate of metastasis formation
Authors: El-Kareh Ardith W. , Secomb Timothy W.
Published: June 2012

That the dependence of the rate of formation of new metastases on the existing tumor volume is weak has been demonstrated from data on the distribution of sizes of metastasic lesions, as well as data on the fraction of tumors that are metastatic as a function of tumor size at diagnosis. A mathematical model for the rate of metastasis formation as a function of tumor size was developed to explain this finding and is presented here. The model includes several stromal cell populations, in particular macrophages and fibroblasts, in addition to tumor cells, which are divided into epithelial- and mesenchymal-like populations. Epithelial-to-mesenchymal transitions are accounted for, as well as key growth factors that mediate tumor-stroma crosstalk and recruitment of stromal cells to the tumor mass. A key feature of the model is cooperativity in the steps involved in the establishment of metastases. Experimental findings of tumor cell-macrophage cooperativity in chemotaxis-driven migration towards microvessels, and EMT/non-EMT cooperativity in tumor cell escape, extravasation and intravasation are incorporated into the model. By involving the product of two or more rates, each of which depend on tumor volume raised to a power less than one, these cooperative processes result in a dependence of the metastatic rate on tumor size that is less than the 2/3 power expected if the rate were merely surface-area dependent. In addition to providing a framework for understanding experimental findings on the kinetics of metastasis, the model should prove useful for investigating the interplay between cell kill rates due to treatment and tumor regrowth kinetics in the most common case where the treated tumor consists of a distribution of metastatic lesions rather than a single mass.

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 39. doi:10.1158/1538-7445.AM2011-39
Abstract 3964: In colorectal cancer cells, the beta-catenin/TCF complex regulates several growth suppressive microRNAs that target cancer promoting genes
Authors: Schepeler Troels , Holm Anja , Halvey Patrick , Nordentoft Iver , Lamy Philippe , Christensen Lise Lotte , Thorsen Kasper , Liebler Daniel C. , Ørntoft Torben F. , Andersen Claus L.
Published: June 2012

Aberrant activation of the Wnt signaling pathway is causally involved in the formation of most colorectal cancers (CRCs). Whereas detailed knowledge exists regarding Wnt regulated protein coding genes, much less is known about the possible involvement of non-coding RNAs. Here we used TaqMan Array MicroRNA Cards, capable of detecting 664 unique human microRNAs (miRNAs), to describe changes of the miRNA transcriptome following disruption of beta-catenin/TCF4 activity in DLD1 CRC cells. Most miRNAs appeared to respond independently of host gene regulation and proximal TCF4 chromatin occupancy. A module of miRNAs suppressed by Wnt signaling in vitro was downregulated in a series of human primary CRCs (n = 46), and CRC cell lines (n = 7), relative to normal adjacent mucosa (n = 14). Several of these miRNAs (miR-145, miR-126, miR-30e-3p, and miR-139-5p) markedly inhibited CRC cell growth in vitro when ectopically expressed. By using an integrative approach of proteomics and microarrays, together interrogating thousands of proteins and genome-wide mRNA levels, we also provide detailed insight into the target gene network controlled by miR-30e-3p. Specifically HELZ and PIK3C2A were directly repressed via several functional seed matching binding motifs located within the transcripts. siRNA-mediated silencing of PIK3C2A partly phenocopied the growth suppressive phenotype of miR-30e-3p suggesting that miR-30e-3p restricts CRC cell growth in part by targeting PIK3C2A. Collectively, our study demonstrates that multiple miRNAs are upregulated as a consequence of forced attenuation of Wnt signaling in CRC cells, and some of these miRNAs inhibit cell growth, possibly through repression of several growth stimulatory cancer-related genes.

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 3964. doi:10.1158/1538-7445.AM2011-3964
Abstract 3968: MicroRNA-34a inhibits proliferation and invasion by targeting c-Myc in prostate cancer cells
Authors: Yamamura Soichiro , Saini Sharanjot , Majid Shahana , Hirata Hiroshi , Ueno Koji , Deng Guoren , Tanaka Yuichiro , Carroll Peter , Dahiya Rajvir
Published: June 2012

MicroRNA-34a (miR-34a), a potent p53 mediator, has been reported to function as a tumor suppressor. The proto-oncogene c-Myc regulates cell proliferation and transformation both transcriptionally and non-transcriptionally and is frequently deregulated in human cancers. Rho GTPases are small G proteins that regulate various cellular processes, including cytoskeletal dynamics, migration, cell proliferation, apoptosis, and transcription. RhoA has been shown to control cancer metastasis and progression and cross-talk between RhoA and c-Myc has been reported. We studied the functional effects of miR-34a on c-Myc and RhoA in PC-3 prostate cancer cells. Transfection of miR-34a into PC-3 cells strongly inhibited in vitro cell proliferation, in vivo xenograft growth and cell invasion and promoted apoptosis. miR-34a downregulated expression of c-Myc by targeting its 3’ UTR as shown by luciferase reporter assays. miR-34a was also found to repress RhoA expression. Overexpression of c-Myc reversed miR-34a suppression of RhoA expression and invasion, suggesting that miR-34a inhibits invasion by suppressing RhoA through c-Myc. We also found that miR-34a downregulated guanine nucleotide exchange factors (GEFs) which convert inactive GTPases to an active form. Our results demonstrate that miR-34a suppresses malignancy by targeting c-Myc in PC-3 prostate cancer 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 3968. doi:10.1158/1538-7445.AM2011-3968
Abstract 3978: DDX20, a suppressor of hepatocarcinogenesis, controls NF-κB activity through regulating the function of miRNA-22 and miRNA-140-3p targeting transcriptional coactivators
Authors: Takata Akemi , Otsuka Motoyuki , Kojima Kentaro , Yoshikawa Takeshi , Kishikawa Takahiro , Ijichi Hideaki , Hirata Yoshihiro , Tateishi Keisuke , Yoshida Haruhiko , Omata Masao , Koike Kazuhiko
Published: June 2012

MiRNA expression profile of human cancers has been characterized by an overall miRNA downregulation. While the causes include a transcriptional silencing and a failure of miRNA maturation, another possibility is that the deregulation of the machinery components for executing miRNA function also may cause similar consequences. Then, we screened the protein expression levels of the established members of the miRNA-containing ribonucleoproteins (Dicer, Ago2, TRBP2, DDX20 also known as Gemin3, and Gemin4) in various organ cancers by immunohisotchemistry. We detected reduced expression of DDX20 only in hepatocellular carcinoma tissues, while the levels of other genes were not drastically changed. We show that DDX20 suppresses NF-κB activity through regulating a subset of miRNA function. A microRNA library screen revealed that miR-140-3p and miR-22 suppress NF-κB activation by targeting the expression of NRIP1 and NCOA1, both are coactivators of NF-κB. However, in DDX20 deficient cells, this suppressive effect was lost, leading to NF-κB activation, a key regulator of hepatocarcinogenesis. In addition, DDX20 knockdown indeed induced cell transformation, revealed by a sphere-forming assay. These results indicate that DDX20 deficiency enhances NF-κB activity by impairing the NF-κB-suppressive action of microRNAs, and suggest that deregulation of the microRNA machinery may be one of the mechanisms of oncogenesis in liver cancers.

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 3978. doi:10.1158/1538-7445.AM2011-3978
Abstract 398: Interleukin 6 may predict chemoresistant ovarian cancer
Authors: Kerr Elizabeth H. , Oelschlager Denise K. , McNally Lacey R. , Grizzle William E.
Published: June 2012

Interleukin 6 (IL-6) has been hypothesized to facilitate the growth and progression of some malignancies by increasing angiogenesis. The aim of this study was to evaluate ovarian ascites from chemotherapy-naïve ovarian cancer patients and determine whether cytokines including IL-6 could predict resistance.

After IRB approval, patient ascites and metastatic implants were collected. The metastatic implants were evaluated for platinum sensitivity by treatment with 50 uM carboplatin for 48 hours and then cell viability was analyzed. The cells were removed by centrifugation from the ascites fluid and expression of IL-6, IL-1a, IL-1ra, IL-8, VEGF, and RANTES was evaluated in the fluid and lysed cells separately using a Millipore Custom Magnetic Bead Kit (Millipore, Billerica, MA) on a Bio-Plex Cytokine Assay (Bio-Rad Laboratories, Hercules, CA).

Twelve patients with advanced stage ovarian papillary serous carcinoma undergoing primary cytoreductive surgery had ascites samples which were adequate for analysis. Six patients were platinum sensitive and 6 patients were platinum resistant. IL-6 levels in the acellular fluid correlated with chemoresistance (P = 0.05). IL-1a and IL-1ra levels tended to be associated with chemoresistance (P = 0.22; P = 0.1) while IL-8 and VEGF levels tended to be associated with chemosensitivity (P = 0.23; P = 0.16). RANTES showed no association with either chemoresistance or chemosensitivity. Levels of cytokines extracted from the cells were low and did not impact the results of analysis of the cytokines. We conclude that levels of IL-6 in ascites may indicate platinum resistance.

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 398. doi:10.1158/1538-7445.AM2011-398
Abstract 3983: MiR-31 isoforms differentially regulate expression of dicer in cancer cells
Authors: Chan Yu-Tzu , Lin You-Chin , Lin Ruey-Jen , Kuo Huan-Hsien , Chiu Kuo Ping , Yu Alice L.
Published: June 2012

MicroRNAs (miRNAs) are a group of small non-coding RNAs involved in several important biological processes. Recent studies have implied that imprecise cleavage of primary or precursor RNA by Drosha or Dicer respectively could produce miRNAs with variations at 5’-and/or 3’-ends, which were termed “isomiR”. The existence of isomiRs may increase the complexity of miRNA biology, although their functions have not been explored. This is further complicated by the observation of variations in the population of isomer for a given miRNA among different species as well as among different types of cells within the same species (human cells), which raises the issue whether these isomers might exert differential effects on target gene regulation. Here, we utilized three miR-31 isoforms (miR-31-H, miR-31-P, and miR-31-M) which differ from each other only slightly in their sequences at both ends, to compare their capacity to regulate a predicted target, Dicer. Interestingly, we found only miR-31-P was able to directly repress Dicer expression in both breast cancer MCF-7 cells and lung cancer A549 cells, resulting in their enhanced sensitivity to cisplatin, which is known to be associated with Dicer knockdown. In line with this, the amount of miR-31-P bound to the RNA-induced silencing complex (RISC) was greater than that of miR-31-H and -M by RNA-CHIP analysis. Furthermore, evaluation of other known miR-31 target genes showed that expression of some target genes was indeed differentially regulated by miR-31 isoforms. Our findings not only revealed Dicer to be a direct target of miR-31, but also demonstrated the disparate functions of isomiRs for the fist time, providing a novel functional mechanism of fine-tuning of gene expression by miRNAs.

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 3983. doi:10.1158/1538-7445.AM2011-3983
Abstract 399: Elevation of angiopoietin-like protein 4 by PGE2 and hypoxia promotes colorectal cancer progression
Authors: Kim Sun-Hee , Park Yun-Yong , Kim Sang-Wook , Lee Ju-Seog , Wang Dingzhi , DuBois Raymond N.
Published: June 2012

Prostaglandin E2 (PGE2), the most abundant COX-2-derived prostaglandin found in colorectal cancers, promotes tumor cell proliferation and survival via multiple signaling pathways. However, the role of PGE2 in tumor hypoxia is not well understood. Here, we show that a synergistic effect of PGE2 and hypoxia on enhancing ANGPTL4 expression and that elevation of ANGPTL4 promotes colorectal cancer progression. PGE2 induces ANGPTL4 expression at both the mRNA and protein levels under hypoxic conditions. Moreover, hypoxia induces one of the prostaglandin receptors, known as EP1. Activation of EP1 enhances ANGPTL4 expression, whereas blockage of EP1 by its antagonist inhibits PGE2 induction of ANGPTL4 under hypoxic conditions. Over-expression of ANGPTL4 promotes cell proliferation and tumor growth in vivo. In addition, treatment with ANGPTL4 recombinant protein increases cancer cell proliferation through stimulating STAT1 activation. These findings are relevant to human disease since we found that the expression of ANGPTL4 and STAT1 are elevated in 50% of human colorectal cancers and there is a positive correlation between COX-2 and ANGPTL4 as well STAT1 expression in the specimens tested. These results indicate that PGE2 plays an important role in promoting cancer cellular adaptive response to hypoxia and cancer progression via ANGPTL4.

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 399. doi:10.1158/1538-7445.AM2011-399
Abstract 3992: Roles of ASH1-miR-375 pathway in development of lung cancers with neuroendocrine features
Authors: Hirotaka Osada , Nishikawa Eri , Arima Chinatsu , Okazaki Yasumasa , Tomida Shuta , Tatematsu Yoshio , Taguchi Ayumu , Shimada Yukako , Yanagisawa Kiyoshi , Toyokuni Shinya , Sekido Yoshitaka , Takahashi Takashi
Published: June 2012

Lung cancers with neuroendocrine (NE) features are often very aggressive, though the underlying molecular mechanisms have not been clearly elucidated. We previously reported that the basic helix-loop-helix protein, achaete-scute homologue 1 (ASH1/ASCL1), a master regulator of pulmonary neuroendocrine cell development, is crucially involved in the pathogenesis of lung cancers with neuroendocrine features (NE-lung cancers). In the present study, we searched for miRNAs regulated by ASH1 in order to gain insight into the involvement of miRNAs downstream of ASH1 in NE-lung cancer pathogenesis. We consequently found that introduction of ASH1 into A549 cells markedly induced miR-375 and down-regulated miR-200b. Interestingly, these two miRNAs inversely affected cell-cell interaction and cell motility, and they together conferred looser cell attachment and a more motile feature. miR-375 was found to be directly transactivated by ASH1. Global gene expression analysis using miR-375-introduced A549 cells and the subsequent pathway analysis using the Ingenuity IPA software revealed altered gene expressions in several cancer-related pathways (e.g., cellular movement and morphology). Interestingly, we also found that miR-375 alone can induce NE differentiation markers in A549 cells and that miR-375 is required to elicit ASH1-indued NE features. In accordance with these findings in vitro, clear induction of NE features as well as enhanced tumor growth was observed in xenografts of A549 cells stably expressing miR-375.

We further found that a transcriptional co-activator YAP1 is most significantly repressed by miR-375 through recognition of its two miR-375 binding sites. A positive correlation between ASH1 and miR-375 as well as a negative correlation between miR-375 and YAP1 were observed in lung cancers, indicating the ASH1-miR-375-YAP1 regulatory pathway is indeed functionally implemented in lung cancer cells. In addition, we found that growth-regulatory functions of YAP1 is cell-lineage dependent in lung cancer cell lines. In conclusion, the present study identified the ASH1-miR-375 axis, providing clues for a better understanding of the molecular and cellular biological roles of ASH1-centered microRNA regulatory networks in the pathogenesis of NE-lung cancers.

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 3992. doi:10.1158/1538-7445.AM2011-3992
Abstract 4006: Orphan nuclear receptor tailless TLX performs an oncogenic function in prostate cancer cells via its promotion of androgen-independent growth and induction of epithelial – mesenchymal transition phenotype
Authors: Wu Ding Lan , Cheng Cho Yiu , Chan Franky Leung
Published: June 2012

The Tailless TLX gene (NR2E1), which was initially identified as a vertebrate homolog to the Drosophila terminal-gap gene tailless (tll), is an orphan nuclear receptor and functions mainly as a constitutive transcriptional repressor. Functional studies show that TLX plays important roles in the maintenance and self-renewal of both embryonic and adult neural stem cells. Transgenic mice with TLX overexpression show that in vivo ectopic TLX expression can lead to uncontrolled expansion of a subgroup of neural stem cells and cause initiation of glioma. In a preliminary screening of expression patterns of nuclear receptors in prostatic cell lines and clinical prostate cancer tissues, we identified that TLX transcripts were significantly overexpressed in many prostate cancer cell lines. Furthermore, by immunohistochemistry, increased TLX nuclear immunosignals were detected in high Gleason-scored (≥4) and also hormone-refractory (castration- and flutamide- resistant) prostate cancer, paired neoplastic human prostatic tissues, suggesting that TLX up-regulation may be positively associated with the advanced progression of prostate cancer. Based on these observations, we hypothesize that TLX may play growth regulatory roles in prostate cancer development. In order to elucidate the functional significance of TLX in prostate cancer growth, we generated stable TLX-infectants in a hormone-sensitive prostate cancer line LNCaP, which expressed low endogenous TLX levels, for growth phenotypic characterization. Our results showed that ectopic TLX expression could enhance the cell proliferation of LNCaP-TLX cells in either normal growth medium or medium with charcoal-stripped fetal bovine serum, accompanied with a decreased p21 expression. The LNCaP-TLX transduced clones, which expressed decreased androgen receptor (AR) and prostatic specific antigen (PSA) expressions, were less sensitive to AR agonist R1881 and antagonist bicalutamide, suggesting that LNCaP-TLX clones were less dependent on androgen but resistant to anti-androgen. Lastly, we also found that LNCaP-TLX infectants become apparently fusiform-shaped and expressed evaluated levels of two epithelial-mesenchymal transition (EMT) markers, Twist and Vimentin, suggesting that an EMT phenotype was induced in LNCaP-TLX cells. Taken together, our results demonstrated for the first time orphan nuclear receptor TLX may play an oncogenic regulatory role in the advanced growth of prostate cancer.

(This study was supported by a Direct Grant for Research CUHK, project code 2041534)

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 4006. doi:10.1158/1538-7445.AM2011-4006
Abstract 4010: Significant roles of p120 catenin and MUC1 in promoting invasive behavior of pancreatic cancer cells
Authors: Liu Xiang , Yi Chunhui , Hollingsworth Michael A.
Published: June 2012

Pancreatic cancer is highly lethal in part because the tumors have metastasized at the time of diagnosis. We are investigating the hypothesis that interactions between the cell surface mucin MUC1 and p120 catenin (p120ctn) modulate cell adhesion, invasion and metastatic properties of pancreatic cancer cells. MUC1 is overexpressed in pancreatic cancer and is known to modulate the invasive and metastatic properties of tumor cells by influencing cell surface adhesion properties directly and by signaling through the MUC1 cytoplasmic tail that reprogram transcription of invasion and metastasis associated genes. Downregulation or mislocalization of p120ctn is correlated with high grade and poor survival in human pancreatic cancer. E-cadherin, which is normally stabilized by p120 catenin in the cell membrane, is frequently lost or downregulated in various human cancers, resulting in the emergence of malignant characteristics, such as loss of epithelial morphology, and gain of invasiveness and metastatic potential. We hypothesized that MUC1 competed with binding of E-cadherin to p120ctn, which enhanced E-cadherin internalization, thus promoting epithelial to mesenchymal transition (EMT). We report here that several p120 catenin isoforms are expressed in human pancreatic cancer and that MUC1 cytoplasmic tail interacts with armadillo repeats of p120ctn. Overexpression of MUC1 resulted in alterations in expression of different p120ctn isoforms, increased nuclear localization of p120ctn, and a decrease in p120ctn association with E-cadherin, as detected by western blotting, co-immunoprecipitations, and confocal microscopy analysis of Capan1 and MIAPACA-2 pancreatic cancer cell lines. Our data support the hypothesis that MUC1 overexpression decreases the association of p120 catenin with E-cadherin, which increases E-cadherin turn over. We also detected colocalization of MUC1 and p120ctn in the nucleus, raising the possibility that this association constitutes a novel signaling pathway mediated by MUC1 and p120ctn that contribute to the reprograming of gene expression during EMT, invasion and metastasis. This research provides novel insight that enable opportunities to develop an effective therapy to prevent pancreatic tumor invasion and metastasis. Supported by grant R01CA57362 from the NCI.

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 4010. doi:10.1158/1538-7445.AM2011-4010
Abstract 402: The role of IL-6 in communication of pancreatic carcinoma cells with fibroblasts
Authors: Kamohara Hidenobu , Kinoshita Kouichi , Kurashige Junji , Tanaka Youhei , Baba Hideo
Published: June 2012

 Pancreatic cancer shows high mortality rates in gastroenterogical neoplasms, and there are difficulties in early diagnosis and aggressive progression. IL-6 has pleiotropic function and are produced by various immunnocompetent cells, as well as cancer cells. Some studies have been demonstrated IL-6 play an important role in evading host immune surveillance in tumor microenvironment, but interactions of fibroblasts has not been fully understood. Therefore, the aim of this study is to reveal role of fibroblasts in pancreatic tumor microenvironment. Especially, we evaluate induction and biologicial function of IL-6 in pancreatic carcinoma cells after the stimulation with various cytokines and fibroblast associated factors.

 Firstly, we examined IL-6 and its receptors expression by RT-PCR and Northern blotting. All 7 tested cell lines expressed gp130 and IL-6R alpha mRNA, 2 cell lines (Hs7667 and Capan1) expressed IL-6 mRNA in serum free condition. To clarify the effect of proinflammatory cytokines on IL-6 expression in Hs766T cells, cells were stimulated with or without cytokines. Northern blotting revealed TNFα and IL-1β upregulated IL-6 mRNA, but not IL-6, IL-8 and LIF. IL-6 did not affect cell proliferation by WTS assay in 7 pancreatic carcinoma cells. In contrast, IL-6 promoted cell motility significantly by gold particles phagocytosis assay (P<0.05) and cell invasion significantly by matrigel insert chamber assay (P<0.05). IL-6 induces phosphorylation of STAT3 in Hs-766T cells, but not AKT. To identify IL-6 expression by interaction between pancreatic carcinoma cells and fibroblasts, we used two established fibroblastic cell lines (MRC-9 and WI-38) isolated from human embryonal lung tissues. Serum free conditioned medium (CM) were collected after incubation for indicated periods. Hs766T originated CM (Hs766T-CM) induced IL-6 and IL-8 mRNA in MRC-9 and WI-38 cells. MRC-9 CM and WI-38-CM did not affect in Hs-766T cells. Co-culture between Hs-766T and MRC-9 cells induced IL-8 mRNA dratically. IL-6 promotes miR-146a and miR155 expression in Hs-766T cells.

 Communication of pancreatic carcinoma cells with fibroblasts affect IL-6 expression and it could contribute to pancreatic cancer progression. Regulation of IL-6 expression in tumor microenvironment would be important for pancreatic cancer therapy.

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 402. doi:10.1158/1538-7445.AM2011-402