bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 789: GSTP1 expression is regulated by MycN and is a marker of poor outcome in childhood neuroblastoma
Authors: Norris Murray D. , Fletcher Jamie I. , Gherardi Samuele , Murray Jayne , Burkhart Catherine , Russell Amanda , Valli Emanuele , Oberthuer Andre , Ashton Lesley J. , London Wendy B. , Marshall Glenn M. , Perini Giovanni , Haber Michelle 
Published: August 2012

Abstract
In childhood neuroblastoma, amplification of the transcription factor MycN is associated with poor outcome and a multidrug resistant phenotype. We have previously shown that MycN regulates the expression of several ATP-binding cassette (ABC) transporter genes, and that these genes represent powerful prognostic markers in neuroblastoma (1,2,3). Although these transporters are able to efflux a wide range of cytotoxic drugs, they do not confer resistance to several important cytotoxic agents used to treat neuroblastoma, including cisplatin and cyclophosphamide, hence we explored the prognostic significance and transcriptional regulation of the phase II detoxifying enzyme, glutathione S-transferase P1 (GSTP1). Using quantitative real-time PCR, GSTP1 gene expression was assessed in a retrospective cohort of 51 patients, and subsequently in a cohort of 207 prospectively accrued primary neuroblastomas. These data, and GSTP1 expression data from an independent microarray study of 251 neuroblastoma samples, were correlated with established prognostic indicators and disease outcome. High levels of GSTP1 were associated with decreased event-free and overall survival in all three cohorts. Multivariate analyses, including age at diagnosis, tumor stage and MYCN amplification status, were conducted on the two larger cohorts and demonstrated independent prognostic significance of GSTP1 expression levels. We also explored the regulation of GSTP1 by MycN using chromatin immunoprecipitation (ChIP) and luciferase reporter assays in neuroblastoma cell lines and found that GSTP1 is a direct transcriptional target of MycN. We conclude that N-Myc regulates multiple components of drug metabolism and efflux pathways, including GSTP1 and transporters of the ABC superfamily. The regulation of these key multidrug resistance mechanisms may have particular significance for malignancies with amplification of Myc family genes. 1) J Biol Chem, 285:19532-19543, 2010 2) J Natl Cancer Institute, 103:1236-51, 2011 4) Nat Rev Cancer, 10:147-156, 2010
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 789. doi:1538-7445.AM2012-789
Abstract 795: Epigenetics, cell cycle and drug-resistant ovarian cancer
Authors: Safuwan Nur Arnida Mohammed , Chivers Pritlata , Crook Tim , Syed Nelofer , Coley Helen M. 
Published: August 2012

Abstract
Epithelial ovarian cancer (EOC) is the most lethal of the gynaecological malignancies and currently stage III/IV disease is associated with a 25% 5 year survival rate. A major factor associated with advanced EOC is the development of drug resistant disease, characterised by a lack of response to platinum and taxane based agents. In an effort to clarify mechanisms underlying chemorefractory EOC we have developed a number of drug resistant cancer cell lines. DNA microarray screening of drug resistant versus drug sensitive cell lines (combining a methylation reversal step using demethylating agents) indicated down-regulation of a number of genes with evidence of epigenetic silencing by promoter methylation in many cases. We have identified P57kip2 a cyclin dependent kinase inhibitor (CDKi) as a gene that is subjected to methylation in carboplatin-resistance, as shown in the PEO1CarbR line. Using a siRNA approach, silencing of the p57kip2 gene in drug sensitive parental PEO1 or SKOV-3 cells gave rise to a reduced sensitivity to platinum agents i.e. cisplatin or carboplatin as assessed using apoptosis with the annexinV assay and flow cytometry. Using chemosensitivity testing (MTT) of PEO1 parental and PEO1CarbR lines versus seliciclib (a CDK2 inhibitory drug) we saw an association with sensitivity to this agent with down-regulation of p57kip2. The IC50 values obtained for the human ovarian cancer cell line PEO1 and PEO1CarboR were 27.4 and 19.2μM, respectively (p = &lt;0.05). Cell cycle analysis of seliciclib treated cells indicated a prolonged S-phase as a marker of increased sensitivity to the drug and an increased apoptotic response in p57kip2 silenced cells. Our data suggest that CDK inhibitors such as seliciclib may have utility in tumours that show downregulation of the endogenous CDKi p57kip2 and identification of such patients may indicate a sub-group that respond preferentially to seliciclib. The same screening platform also enabled us to identify wee1 and stratifin (14-3-3α) as genes significantly downregulated in taxane-resistant cell lines. The 2 gene products are important in maintaining genomic stability alongside other proteins such as Chk1 and ATR. Wee1 controls G2M by keeping CDK2/Cyclin B inactive whilst binding of 14-3-3 isoforms enhances its activity. Demethylation treatment using 5′aza-cytidine and Trichostatin A unmasked gene expression, indicating that these genes are hypermethylated in taxane-resistant cell line. Current work aims to confirm further the role of these 2 genes in drug resistance by a series of knock-in and knock-out experiments.
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 795. doi:1538-7445.AM2012-795
Abstract 796: Novel mechanisms of drug resistance in leukemia cells associated with changes in HoxA9 and microRNA expression
Authors: Ho Tsui-Ting , He Xiaolong , Beck William T. 
Published: August 2012

Abstract
The acquisition of resistance to anticancer drugs is a key obstacle to successful cancer therapy. An increasing number of studies have investigated the roles of microRNAs in drug resistance. We previously reported that the upregulation of miR-135b and miR-196b correlated positively with acquired drug resistance in the human T-cell leukemia cell line, CCRF-CEM (CEM), and that the elevation of expression of these two microRNAs in response to the DNA damaging agent etoposide appears to be histiotype-specific (T-T Ho et al, Proceedings of the 102nd Annual Meeting of the AACR 2011). To develop a mechanistic understanding of why these microRNAs are differentially expressed, we have studied miR-196b, which maps between the HoxA9 and HoxA10 genes on chromosome 7p15.2, suggesting that miR-196b and HoxA genes might be co-activated. Indeed, we found upregulation of HoxA9 mRNA after short-term (48 h) exposure of CEM cells to the topoisomerase II inhibitors etoposide and doxorubicin. Of note, we also found that HoxA9 is constitutively overexpressed in multidrug-resistant CEM/VM-1-5 cells. Of interest, we found that HoxA9 is clearly associated with drug resistance, as knockdown of HoxA9 using esiRNA (a heterogeneous mixture of siRNAs that all target the same mRNA) partially sensitized multidrug-resistant CEM/VM-1-5 cells to etoposide. This indicates that the expression of miR-196b is linked to HoxA gene transcription and to drug responsiveness. We subsequently confirmed that the expression of HoxA9 mRNA follows the same pattern in other leukemia cells. For example, both miR-196b and HoxA9 are upregulated in response to short-term etoposide exposure in HL-60 (acute promyelocytic leukemia), but not in solid tumor-derived MCF7 (breast cancer cell line) and its etoposide-resistant subline MCF7/VP, or Rh30 (rhabdomyosarcoma cell line) and its etoposide-resistant subline, Rh30/V1. We are presently assessing the role of HoxA9 in drug resistance in other leukemia cell lines and investigating the mechanistic basis for this effect. In summary, we report here a novel mechanism of anticancer drug resistance in leukemia cells that is associated with HoxA9 and specific changes in microRNA expression. This is the first report that HoxA9 may impact on anticancer drug resistance. (Supported in part by R01 CA40570 from NCI to WTB, and in part by UIC.)
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 796. doi:1538-7445.AM2012-796
Abstract 799: Comprehensive proteomic analysis of cisplatin resistance in ovarian cancer
Authors: Teng Pang-ning , Hood Brian L. , Litzi Tracy , Chappell Nicole P. , Hamilton Chad A. , Maxwell G. Larry , Conrads Thomas P. 
Published: August 2012

Abstract
We have conducted a comprehensive proteomic analysis of an ovarian cancer cell line (A2780) and its cisplatin resistant daughter line (A2780-CP20) to identify key regulators and signaling pathways that confer cisplatin resistance. Quantitative proteomic profiling was conducted of defined biological compartments including that from global lysates, the nuclear fraction, the phosphoproteome and the secretome. Total cell lysates and nuclear fractions were harvested from A2780 and A2780-CP20 cultured in the presence or absence of cisplatin (3 µM) for 72 h. The secretome fractions were collected from A2780 and A2780-CP20 cultured in serum-free, phenol red-free media in the presence or absence of cisplatin (3 µM) for 24 h. Phosphopeptides were enriched from peptide digests of total lysates of A2780 and A2780-CP20 cultured in the presence or absence of cisplatin (3 µM) for 15 min using TiO2. Sample digests were analyzed by high-resolution LC-MS/MS that resulted in the identification of 2703, 2286, 1815, and 1362 proteins from the global, nuclear, secretome, and phosphoproteome fractions, respectively. Spectral counting was utilized to quantify the relative abundance of proteins identified. Nuclear proteins identified at elevated abundance in the cisplatin resistant A2780-CP20 including an array of chromatin remodeling proteins, such as SATB1, SATB2, coilin, AT-rich interactive domain-containing protein 3A (ARID3A), ARID3B, and ARID3Cwere validated by Western blot and qPCR in A2780/A2780-CP20 as well as other gynecologic cancer cell lines. Modulation of the abundance level of these candidates and the phenotypic impact on cisplatin resistance utilizing shRNA knockdown will be described. Differential proteins selected from the secretome analysis for western blot validation include Fras1-related extracellular matrix protein 2 (FREM2), stanniocalcin-1 (STC1), angio-associated migratory cell protein (AAMP), plasminogen activator inhibitor 1 (SERPINE1), high mobility group protein B1 (HMGB1), and chloride intracellular channel protein 2 (CLIC4), stromelysin-2 (MMP10), interstitial collagenase (MMP2), and CD166 antigen. Validated candidate protein targets from the secretome analysis will be tested by IHC on formalin fixed tissue sections as well as ELISA and multiple reaction monitoring (MRM) by mass spectrometry in serum from recurrent and non-recurrent ovarian cancer patients.
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 799. doi:1538-7445.AM2012-799
Abstract 802: A key role for ARF in drug resistance in invasive bladder cancer
Authors: Kobayashi Takashi , Delto Joan C. , Abate-Shen Cory 
Published: August 2012

Abstract
Although most superficial bladder cancers can be removed transurethrally with excellent prognosis, clinical outcome is much more problematic for patients with muscle-invasive disease. Indeed, invasive bladder cancer is a major clinical challenge since it is highly associated with postoperative recurrence and metastasis. Current treatments for those lethal forms of bladder cancer include systemic chemotherapy and molecular targeted therapy; however, survival is poor since most patients develop resistance to the drugs within a short timeframe. Clearly, there is a need to identify novel therapeutic options for invasive bladder cancer as well as a greater understanding of the molecular mechanisms of drug resistance. We have been investigating mechanisms of drug resistance using genetically-engineered mouse models of invasive bladder cancer based on the combinatorial deletion of p53 and Pten in bladder epithelium. p53 and PTEN are frequently inactivated in human bladder cancers, particularly those with poor prognosis. Indeed, allograft tumors established from these mice responded initially to the treatment with cisplatin, docetaxel, or rapamycin but eventually developed resistance. We have observed that these p53; PTEN deficient tumors express robust levels of p19Arf, while targeted deletion of Arf retards the aquisition of resistance following drug treatment. The significance of this expression was further suggested by analysis of a published gene expression profile of human bladder cancers which revealed that high Arf expression is an independent predictor of poor survival of invasive bladder cancer patients. Furthermore, following drug treatment in the mouse model, the Arf-positive, compared to the Arf-negative, tumors were significantly enriched in extracellular matrix/integrin signaling gene signature consistent with activation of downstream PI3K-mTOR pathway, suggesting that a model for drug resistance is via PI3K pathway activation. We have observed similar results in human bladder cancer cell lines either following knock-down of p14Arf in J82 cells that express endogenous p14Arf or following forced expression of p14Arf in ARF-negative UMUC3 human bladder cancer cells, and in both cases it was coincident with deregulated activation of PI3K-mTOR pathway. Thus, we propose that Arf confers drug resistance on bladder cancer by activating PI3K-mTOR pathway, highlighting a potential therapeutic target for advanced invasive bladder cancer patients.
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 802. doi:1538-7445.AM2012-802
Abstract 805: The role of aldo-keto reductases and estrogen signalling in acquired anthracycline resistance
Authors: Chewchuk Simon , Parissenti Amadeo M. 
Published: August 2012

Abstract
Breast cancer is the second leading cause of death from cancer in North American women. The disease can be difficult to treat by adjuvant or neoadjuvant chemotherapy because of intrinsic or acquired resistance to chemotherapy agents. To better understand the mechanisms for acquired resistance to the anthracycline class of chemotherapy agents in breast cancer, a series of MCF-7 breast tumour cell lines have been developed that exhibit progressive resistance to epirubicin (MCF-7EPI cells) or to doxorubicin (MCF-7DOX2 cells). Following mRNA microarray analysis, several genes were identified whose expression was associated with the acquisition of anthracycline resistance. Among these were several Aldo-keto Reductases (AKRs) responsible for estrogen synthesis from estrone and anthracycline detoxification to 13-hydroxymetabolites. AKR 1C3 showed more than a 10-fold increase in expression in anthracycline-resistant breast tumour cells. We hypothesized that the over-expression of AKR 1C3 would lead to both increased drug detoxification and an increase in estrogen synthesis. This would result in increased tumour cell survival and growth in the presence of anthracyclines. Recently, we observed that estrogen levels were, in fact, increased as cells became anthracycline-resistant. In contrast, the expression of estrogen receptor ≤ (ESR1) was reduced by 2- to 5-fold at the gene level and 2- to 20- fold at the protein level, with a concomitant reduction in the estrogen-dependent expression of Bcl-2 and Cyclin D1. Diminished Bcl-2 and cyclin D1 expression would be expected to reduce the growth rate of the cells, a hypothesis we have confirmed in cell culture experiments. Taken together, our findings suggest that selection for anthracycline resistance in breast tumour cells results in alterations in AKR expression, resulting in enhanced detoxification of doxorubicin, the promotion of estrogen biosynthesis, and the reduced estrogen-dependent expression of Bcl-2 and cyclin D1. The reduced expression of Bcl-2 and cyclin D1 blunts the growth rate of anthracycline-resistant cells, which would further increase the ability of these cells to survive in the presence of anthracyclines.
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 805. doi:1538-7445.AM2012-805
Abstract 806: Extracellular matrix metalloprotease inducer (EMMPRIN) and CD44 protein complexes are exclusively formed in basal- and normal-like breast cancer cell lines
Authors: Timmermans Annemieke M. , Montazeri Hamed , Trapman-Jansen Anita M. , Martens John W. , Foekens John A. , Umar Arzu 
Published: August 2012

Abstract
Extracellular Matrix Metalloprotease Inducer (EMMPRIN) is a multifunctional glycoprotein that is involved in tumor cell invasion and metastasis, and is a predictor for tamoxifen resistance in breast cancer. EMMPRIN is implicated in development of therapy resistance by forming a functional transporter complex through interaction with CD44 and monocarboxylate transporter 4. Presence of EMMPRIN transporter protein complexes may therefore be a better predictor for therapy resistance and a direct target for drugs. In this study, we aimed to identify EMMPRIN-CD44 protein interactions in a large panel of breast cancer cell lines. EMMPRIN-CD44 protein interaction was investigated in a panel of 41 breast cancer cell lines, which represent the luminal (n=12), ErbB2 (n=13), basal (n=7), and normal-like (n=9) intrinsic subtypes, using in situ Proximity Ligation Assay (isPLA). In addition, protein expression of both EMMPRIN and CD44 in the cell lines was evaluated by immunohistochemistry (IHC). IHC and isPLA read-out was performed by bright field microscopy and 0-1-2-3 scoring was applied to none-weak-moderate-strong staining (IHC) or interaction (isPLA), respectively. Moderate and strong EMMPRIN expression was observed in 50% of luminal, 36% of ErbB2, 86% of basal, and 100% of normal-like cell lines, and moderate to high CD44 expression was detected in 64%, 83%, 86%, and 100% in luminal, ErbB2, basal, and normal-like cell lines, respectively. Interestingly, moderate to strong EMMPRIN-CD44 interaction was exclusively detected in basal (64%) and normal-like (67%) cell lines, whereas luminal and ErbB2 cells lines had no detectible, or only very weak, EMMPRIN-CD44 interaction (≥square = 23.5, P&lt;0.0001). Our results indicate that EMMPRIN-CD44 protein complexes are formed exclusively in basal and normal-like breast cancer cell lines. These breast cancer subtypes are associated with an aggressive phenotype and poor patient survival. We speculate that active EMMPRIN-CD44 transporters are involved in drug resistance, resulting in poor clinical outcome, and will investigate this in more detail in clinical breast cancer specimens.
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 806. doi:1538-7445.AM2012-806
Abstract 809: Prenatal and postnatal management of infants at 100%-risk for developing retinoblastoma
Authors: Chan Helen S.L. , Dimaras Helen , Héon Elise , Khetan Vikas , Gallie Brenda L. 
Published: August 2012

Abstract
Purpose: Prenatal diagnosis by amniocentesis of infants at 100%-risk of developing retinoblastoma (RB) is possible when the familial RB1 mutation is known in the parent. Since retinal tumors may develop in the third trimester, we assessed the success of a protocol of early delivery of such infants for early institution of therapy with the aim of optimizing outcome. Methods: Since 1999, we treated ten 100%-risk infants with early delivery in a Special Pregnancy Unit, at 32-37 weeks gestation and when deemed to be safe by their obstetrician. From birth, weekly dilated indirect fundoscopy, and/or contact imaging, and/or optical coherent tomography (OCT) examinations were performed with no sedation, with 3-weekly examinations under anesthesia (EUAs) only started once the first tumor was identified, or by the age of 3 months. The tumors were ablated by focal laser therapy and/or cryotherapy. In selected cases, subtenons topotecan (local chemotherapy that causes little side-effects systemically), was used to reduce the sizes of tumors that were too large, or near the optic nerve, or affecting the macula, for focal therapy ablation. When possible, low-dose or single-agent systemic chemotherapy was avoided to avoid induction of the multidrug resistance (MDR) P-glycoprotein in the tumors. If indicated, short-course but high-dose cyclosporin (CSA) MDR-circumventing high-dose carboplatin-etoposide-vincristine (CEV) chemotherapy was given as soon as the infant's immature renal function normalized. Secondary malignancy-inducing radiation and/or eye enucleation was only used for tumors progressing under this regimen. Results: At median followup of 5.7 years (range 0.7-11.7 years), both eyes were saved in 9 children, seven with 20/20-20/50 vision in at least one eye (two were too young for vision-testing), and only one child required radiation and then enucleation of one eye, but retained 20/30 vision in the remaining radiated eye. Five children were only treated with focal laser therapy and/or cryotherapy, two with added subtenons topotecan, four with 1 to 4-cycle CSA-modulated CEV, and one with 2-cycle non-CSA-modulated/dose-adjusted CEV because of immature renal function. Conclusions: This protocol warrants multicenter trial to confirm the favorable efficacy with low toxicity and excellent vision preservation.
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 809. doi:1538-7445.AM2012-809