bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract LB-223: An open-label, exploratory phase II study of oral itraconazole for the treatment of basal cell carcinoma
Authors: Kim Daniel , Kim James , Spaunhurst Katrina , Montoya Javier , Chandra Kalyani , Khodosh Rita , Fu Teresa , Epstein Ervin H. , Molgo Montserrat , Beachy Philip , Tang Jean Y.
Published: August 2012

Purpose: Itraconazole is an FDA-approved antifungal drug that has been recently shown to antagonize the Hedgehog (Hh) signaling pathway, a crucial driver of basal cell carcinoma (BCC) tumorigenesis. As oral itraconazole reduced BCC growth in mice, we assessed itraconazole's efficacy in treating human BCC tumors in an open-label, exploratory phase II study. Patients and Methods: Patients with at least one BCC tumor greater than 4 mm in diameter and with no co-morbidities were eligible to enroll. Patients were enrolled in 2 cohorts to receive oral itraconazole 200 mg twice-daily for one month (Cohort A) or 100 mg twice-daily for a longer duration (Cohort B). The primary endpoint was to determine changes in tumor size, proliferation (Ki67 levels), and a target gene of the Hh pathway (GLI1 mRNA). Results: Of the 29 patients that enrolled in the clinical trial, 19 patients were treated with itraconazole. Itraconazole caused 2 treatment-related adverse events (grade 2 fatigue and grade 4 CHF). Tumors treated with itraconazole showed a 23% reduction in clinical tumor area (95% CI: 17.2% to 28.1%), a 45% reduction in cell proliferation (P=0.04), and a 65% reduction in Hedgehog activity (P=0.03). Eight subjects with multiple tumors were assessed for clinical size changes: 4 subjects had partial response and 4 had stable disease. Tumors from control patients and patients previously treated with other Hedgehog inhibitors saw no significant changes in cell proliferation or Hedgehog activity. Conclusion: Itraconazole reduced BCC tumor size, tumor proliferation, and Hedgehog pathway activity in this exploratory study. Additional studies with larger numbers of patients are needed to validate these findings, however this proof-of-concept study demonstrates the possibility of repurposing FDA approved drugs for the treatment of cancers driven by the Hedgehog signaling pathway.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-223. doi:1538-7445.AM2012-LB-223
Abstract LB-228: Association of XRCC1 SNPs with clinical response in AML patients
Authors: Mitra Amit K. , Crews Kristine , Pounds Stanley , Cao Xueyuan , Rubnitz Jeffrey , Ribeiro Raul , Lamba Jatinder K.
Published: August 2012

DNA repair system is critical in maintaining genome stability and integrity in response to various exogenous and endogenous stress factors. It is a multistep processes involving several enzymes including XRCC1 (X-ray repair cross-complementing group1) protein which plays a vital role in DNA repair activities and therefore is important for maintenance of genetic stability. The current study involves investigation of single nucleotide polymorphisms (SNPs) in the XRCC1 gene and their association with clinical response in pediatric acute myeloid leukemia (AML) patients treated with cytarabine (ara-C) based anti-leukemic chemotherapy in the St. Jude AML02 clinical trial. The St. Jude AML02 trial enrolled 232 AML patients less than 22 years of age, randomized to receive induction I therapy containing high-dose cytarabine or low-dose cytarabine plus daunorubicin and etoposide. A total of eighteen XRCC1 SNPs were genotyped using MALDI-TOF based Sequenom assay and screened for association with 3 endpoints, namely: in vitro ara-C LC50 determined in leukemic cells obtained at diagnosis (which was measured by treating leukemic cells in vitro with varying concentrations of ara-C), event free survival (EFS) and overall survival (OS). Jung statistic was used to determine association of the number of minor alleles with EFS and OS. Association of genotypes with EFS and OS was measured using Cox regression models while considering previously identified prognostically important variables. Our results showed significant association of 4 XRCC1 SNPs with survival and ara-C LC50 in pediatric AML patients. Three of these were present in the coding region, while one was a regulatory SNP located in the promoter region of the XRCC1 gene. XRCC1 SNPs have also been shown to be associated with cancer susceptibility and survival in previous studies. Our results now demonstrate clinical significance of XRCC1 SNPs in pediatric AML and suggest a role of these SNPs as prognostic factors in AML chemotherapy. These results might open up opportunities for tailored chemotherapy based on genomic markers to improve therapeutic outcome.

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 LB-228. doi:1538-7445.AM2012-LB-228
Abstract LB-241: Targeting cancer cells and anti-tumor effects of brucine immuno-nanoparticles on hepatocellular carcinoma in vivo
Authors: Qin Jianmin
Published: August 2012

BACKGROUND and AIMS: In vitro and in vivo studies have showed that brucine can inhibit the growth of liver cancer cells and animals with bearing cancer, and may be a promising anti-cancer drugs. However, high toxicity, poor water solubility, short half-life, narrow therapeutic window, close therapeutic and toxic dose limit its clinical application in malignant tumor treatment. In this study, we report on the preparation, in vivo disrtibution and anti-tumor effect of the brucine immuno-nanoparticles. METHODS: Anionic polymerization and chemical modification technology was used to prepare carboxylated polyethylene glycol-poly lactic acid copolymer carrier material, phacoemulsification technology was employed to prepare carboxylated polyethylene glycol-polylactic acid copolymer brucine nanoparticles and chemical coupling technology was utilized to develop anti-human AFP McAb-polyethylene glycol-poly lactic acid copolymer brucine immuno-nanoparticles. The nude mice in situ transplanted liver cancer model was established by surgical technique, and the brucine immuno-nanoparcitles was injected by caudal vein at indicated time. The liver and kidney function and AFP level were assayed, and the anti-tumor effect was observed after intravenous administration of the brucine immuno-nanoparticles.RESULTS: This results showed that in vivo application of brucine immuno-nanoparticles caused temporary liver and kidney functions damage and significantly reduced AFP secretion. Brucine immuno-nanoparticles had good slow releasing and tumor targeting properties. The brucine immuno-nanoparticles inhibited CD34 expression and angiogenesis of tumor tissues, induced tumor apoptosis, and inhibited tumor growth. CONCLUSIONS: The brucine immuno-nanoparticles has good tumor targeting and obvious anti-tumor effects, and is a promising targeted drug for liver cancer therapy in the future.

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 LB-241. doi:1538-7445.AM2012-LB-241
Abstract LB-245: Investigating the role of BRCA1 in sensitivity to GRN163L, a telomerase template antagonist
Authors: Phipps Elizabeth A. , Gryaznov Sergei , Herbert Brittney-Shea
Published: August 2012

BRCA1 is a tumor suppressor gene with a variety of functions related to safeguarding genomic integrity. Regulation of telomere length is crucial in maintaining genomic stability, with critically short telomeres leading to telomere uncapping, end-to-end fusions, activation of the DNA damage response, and cell cycle arrest. Recent evidence suggests knockdown of BRCA1 in cell lines increases both telomerase activity and average telomere length, but likely results in more unstable telomeres compared to BRCA1 wild-type cell lines. The objective of this study was to determine whether GRN163L, a telomerase template antagonist currently in clinical trials, has enhanced activity in BRCA1 mutant breast or ovarian cancer cell lines compared to paired BRCA1 wild-type breast/ovarian cancer cell lines. In addition, we sought to determine whether BRCA1 cell lines have shorter average telomere lengths than other cancer cell lines, making them more amenable to inhibition of telomerase activity. We utilized a panel of breast and ovarian cancer cell lines harboring both N-terminal and C-terminal BRCA1 mutations, in addition to matched cells expressing exogenous wild-type BRCA1, and assessed the effects of GRN163L or a mismatch oligonucleotide on telomerase activity and telomere length using the TRAP (Telomere Repeat Amplification Protocol) and TeloTAGGG assays, respectively. All cell lines tested exhibited a dose-dependent response to treatment with GRN163L, but not a mismatch control oligonucleotide. In addition, we observed differential sensitivity between BRCA1 mutant and BRCA1 wild-type cell lines tested to clinically relevant concentrations of GRN163L in both TRAP and clonogenic survival assays. Of interest, the majority of the cell lines tested showed gross morphological changes as early as 12 hours following inhibitor treatment. We found UWB1.289 cells have a shorter average telomere length at baseline compared to their BRCA1 wild-type counterpart cells, and saw progressive telomere shortening over a three-week period of treatment with GRN163L, but not with mismatch oligonucleotide. Furthermore, long-term (12 week) treatment with GRN163L preferentially induced complete cell death in the HCC1937 (BRCA1 mutant) breast cancer cell population compared to the HCC1937 cells reconstituted with wild-type BRCA1. Finally, we demonstrate that pretreatment with GRN163L acts synergistically with cis-platin in UWB1.289 and UWB1.289+BRCA1 ovarian cancer cells. In summary, this work provides insight into the role of BRCA1 mutations in cancer cells and their impact on sensitivity to the cellular effects of telomerase antagonism.

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 LB-245. doi:1538-7445.AM2012-LB-245
Abstract LB-246: Epithelial-mesenchymal transition (EMT) does not necessarily decrease the sensitivity of cancer cells to chemotherapeutic agents
Authors: Mezencev Roman , Jabbari Neda , McDonald John F.
Published: August 2012

Epithelial to mesenchymal transition (EMT) has been recently associated with metastatic competence and therapy resistance of cancer cells and the need for development of EMT-targeted therapies has been emphasized. In this report we address the differential responses of breast cancer cell lines with epithelial and mesenchymal phenotypes to anticancer agents using pharmacoinformatics and experimental approaches. First, we identified breast cancer cell lines with epithelial-like and mesenchymal-like phenotypes among the National Cancer Institute (NCI) panel of 60 cell lines and analyzed their differential responses to 10,081 anticancer agents. Second, we evaluated chemotherapeutic response of a mesenchymal-like isogenic breast cancer cell line (MCF-7-Snail) stably transfected to express the EMT-inducing Snail transcription factor and its epithelial-like precursor cell line transfected with the control plasmid (MCF-7-neo). The results of both approaches are inconsistent with the claim that mesenchymal-like cancer cells are generally more resistant to anticancer agents. We found that most of the 10,081 agents examined did not display significantly different potencies between epithelial-like and mesenchymal-like cells. Of the 10,081 anti-cancer agents examined, only 78 displayed consistent differences in effect between epithelial-like and mesenchymal-like cells and all of these agents displayed a more potent effect against mesenchymal-like cell lines. MCF-7-Snail cells were found to be more sensitive to the cytotoxic effects of doxorubicin, 5-FU and methotrexate, while MCF-7-neo cells were more sensitive to gemcitabine and docetaxel and both of these isogenic cell lines were equally responsive to mitomycin C and vincristine. The relatively lower sensitivity of MCF-Snail cells to docetaxel and gemcitabine can be explained by their overexpression of TUBB4 and RRM1, respectively, as demonstrated by gene expression analysis (U133 Plus 2.0 Affymetrix microarrays). In contrast, the higher sensitivity of MCF-7-Snail cells to 5-FU may be due to the down-regulation of the DPYD gene in these cells. Compared to isogenic epithelial cells, MCF-7-Snail cells display down-regulation of the anti-apoptotic genes XIAP, BCL2L1 and NAIP. Collectively, our results indicate that EMT per se does not generally result in a greater resistance of cancer cells to chemotherapeutic agents, but it may, in some instances, result in increased sensitivity of cancer cells to specific chemotherapeutic agents.

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 LB-246. doi:1538-7445.AM2012-LB-246
Abstract LB-25: Activation of AMPK by ATM in reponse to AICAR and metformin
Authors: Yang Da-Qing , Cleary Margot P.
Published: August 2012

AMPK is an AMP-activated protein kinase that plays a key role in regulating cellular energy homeostasis. Metabolic stress, such as heat shock and glucose starvation, causes energy deficiency in the cell and leads to elevated levels of intracellular AMP. This results in the phosphorylation and activation of AMPK. LKB1, a tumor suppressor, has been known as an upstream kinase of AMPK. We found that in response to treatment with 5-aminoimidazole-4-carboxamide-1-b-4-ribofuranoside (AICAR), a LKB1-null cancer cell line, HeLa, still exhibited AMPK phosphorylation. This indicates the existence of an LKB1-independent AMPK protein kinase. ATM is a protein kinase that is deficient in the disease ataxia telangiectasia (A-T). We measured the activation of AMPK by AICAR in the normal mouse embryo fibroblast (MEF) cell line, A29, and the MEF cell line lacking the ATM protein, A38. In A38 cells, the level of AICAR-induced AMPK phosphorylation was dramatically lower than that found in A29 cells. Furthermore, phosphorylation of AMPK in HeLa and A29 cells was inhibited by an ATM specific inhibitor, KU-55933. Our results demonstrate that AICAR treatment could lead to phosphorylation of AMPK in an ATM-dependent and LKB1-independent manner. Similar to the results of AICAR treatment, our work also revealed that the metformin-induced phosphorylation of AMPK in A38 cells is significantly lower than that in A29 cells. We also examined the effect of ATM on AMPK in rat hepatoma cell line H4IIE. Inhibition of ATM by KU-55933 dramatically reduced the phosphorylation of AMPK in response to metformin in this cell line. Thus, ATM may act as a potential AMPK kinase in response to both AICAR and metformin treatment. Metformin is the most commonly prescribed pharmaceutical drug for type 2 diabetes (T2D). In addition, patients with T2D or obesity/insulin resistance who take metformin have reduced rates of cancer occurrence, including breast cancer. However, the mechanism underlying metformin's effect on cancer prevention and/or treatment is unclear (Nature, New & views, Feb. 2011; Science, News Focus, Jan. 2012). While ATM acts as a sensor of DNA damage by controlling cell cycle progression, it also has glucose regulatory function. Our results put ATM as a novel player in the AMPK signaling pathway in response to metformin. These findings provide new insights into the mechanisms by which metformin functions as a preventive and/or therapeutic agent for cancer.

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 LB-25. doi:1538-7445.AM2012-LB-25
Abstract LB-261: A novel notch-AKT-NF-KB axis in triple negative breast cancer cells
Authors: Backus Kandis V. , Peng Y , Hicks C , Kumar S , Kundu G , Pannuti A , Miele L
Published: August 2012

BACKGROUND: Basal-like and claudin-low are two major subgroups of triple-negative breast cancers (TNBC). The clinical subtype claudin-low is represented by MDA-MB 231 cells. The Notch and NF-κB signaling pathways are known to regulate proliferation, differentiation, and apoptosis by regulating the transcription of target genes. Both pathways are commonly active in TNBC. There is strong evidence for cross-talk between these pathways: We previously published that in cervical cancer cells, Notch-1 can activate NF-kB through nuclear IKKα. We published that Notch-1 can activate the estrogen receptor alpha (ERα), also through nuclear IKKα and the IKK signalosome in T-LL cells. However, the mechanism(s) of IKK downstream of Notch remain unknown. Notch1 is highly expressed in TNBC, and Notch ligands Jagged1 and 2 correlate with poor prognosis. IKKα (CHUK) is expressed in all subtypes of TNBC. We investigated whether Notch-1 can activate NF-kB in TNBC cells of claudin-low and basal like subtypes, whether this requires IKKα and how IKKα is activated. METHODS: We used Retroviral RNAi transduction of MDA-MB231 cells to establish Notch1 siRNA. ChIP (chromatin Immunoprecipitation), CoIP (co-immunoprecipitation), Western blot, luciferase reporter assays, co-culture MDA-MB 231 cells with LTK-JAG mouse fibroblasts, qPCR, xenograft tumors in nude mice. RESULTS: We have determined that phosphorylation of Akt is mediated through a non-canonical Notch signaling pathway and this is dependent on PTEN status. Unlike the canonical Notch pathway, Notch activation by Jagged1-expressing stroma cells leads to phosphorylation of Akt within minutes of contact between Jagged1-expressing stroma cells in PTEN wt, MDA-MB 231 cells through a non-transcriptional mechanism. Our data suggest that Notch complexes with PI3K subunits, p85 and p110, after ligand-mediated activation. Inhibition of Notch activity through GSIs (γ-secretase inhibitors) leads to decreased phosphorylation of Akt. Dominant-negative AKT abolishes IKKα phosphorylation. Additionally, the combination of the AKT inhibitor, perifosine and gamma-secretase inhibitor MRK-003 is synergistic in vitro and highly active in MDA-MB231 xenografts. CONCLUSIONS: Our findings suggest a novel non-canonical cross-talk mechanism including Jagged, Notch, AKT and IKKα connecting three major oncogenic pathways in TNBC: Notch, AKT and NF-kB. Moreover, our findings suggest that Akt inhibitors may be combined with GSI for therapeutic purposes.

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 LB-261. doi:1538-7445.AM2012-LB-261
Abstract LB-266: Expression of AGR2 in lung cancer cells needs an active Hippo pathway co-activator, YAP1
Authors: Dong Aiwen , Tun May , Wodziak Dariusz , Gupta Aparna , Lowe Anson
Published: August 2012

Background/Objective: We have previously established that Anterior Gradient-2 (AGR2) affects cancer cell growth by activating YAP1 of the Hippo pathway and inducing AREG of the EGF pathway. Although significant advances have been made concerning the growth promoting effects of AGR2 on cancer cells, including those derived from the pancreas, lung and esophagus, little is known about how AGR2 expression is regulated. Because of AGR2's potential role in human cancer and its established role in organ development in lower vertebrates, we explored the mechanisms responsible for its expression. Methods: ShRNA mediated specific knockdown of YAP1 was conducted in H460 human lung cancer cells. Quantitative real-time PCR was performed to confirm the knockdown efficiency. The expression of AGR2, AREG, and the YAP1-induced genes CTGF, CYR61, COL8A1 was assayed by quantitative real time PCR after YAP1knockdown. The effect of YAP1 knockdown on AGR2 protein was evaluated by immunoblotting. Finally, an AGR2 expression reporter based on the firefly luciferase gene was employed to evaluate whether YAP1 acts on AGR2 promoter activity. Results: Reduced YAP1 expression by lentivirus mediated shRNAmir transduction was further confirmed by western blotting and was also supported by the decrease of YAP1 readouts, such as CTGF. A 95% knockdown of YAP1 expression in H460 cells resulted in a significant morphological change and a 275-fold decrease in AGR2 mRNA. As demonstrated in previously published work, AREG expression was also decreased by 40-fold. Western blots showed that in YAP1 knockdown cells (YAP1KD), there was only negligible levels of AGR2 protein. The data suggested that active YAP1 protein is required for AGR2 expression. The decrease of AGR2 mRNA expression by YAP1KD could be transcriptional or posttranscriptional. To address this question, an AGR2 promoter assay to answer whether YAP1 affects AGR2 transcription. Our AGR2 reporter assay showed that there was more than 5 times more luciferase activity in YAP1KD cells compared to cells infected with the control lentivirus not targeting to any known gene, suggesting that AGR2 expression is regulated in a post-transcriptional manner. Conclusion: YAP1 decreases AGR2 mRNA through a post-transcriptional mechanism, which may include microRNAs. There are four potential miRNA binding sites in the 3-UTR region of AGR2 transcripts. Future experiments will explore if any of these miRNAs are induced upon YAP1 knockdown. This work provides insight into the crosstalk between YAP1 and AGR2, which may have significant implications in lung cancer carcinogenesis.

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 LB-266. doi:1538-7445.AM2012-LB-266
Abstract LB-273: Transcriptional regulation by androgen receptor in prostate cancer
Authors: Zhao Jonathan , Runkle Christine , Wu Longtao , Jin Hong-Jian , Yu Jindan
Published: August 2012

Transcriptional regulation by the androgen receptor (AR) is critical to prostate cancer development and progression. Through integrative analysis of genome-wide AR occupancy and androgen-regulated gene expression, we have recently reported AR as a globally acting transcriptional repressor. This repression is mediated by androgen responsive elements (ARE) and dictated by Polycomb group protein EZH2 and repressive chromatin remodeling. In addition, AR-repressed genes are enriched for developmental regulators controlling cell differentiation. They tend to get down-regulated in advanced prostate cancer probably accountable for stem cell-like de-differentiation and thus tumor progression. However, critical AR-repressed genes of functional relevance are yet to be identified and their roles to be carefully characterized. Through meta-analysis of several expression microarray data, we nominate one top candidate AR-repressed gene. Using this gene as a model, we present further evidence that AR directly inhibits gene expression through physically binding to the enhancer, establishing promoter-enhancer DNA looping, and inducing repressive chromatin remodeling. Further, overexpression of this gene inhibits prostate cancer cell growth, migration, and invasion in vitro and xenograft tumor growth in mice, thus exhibiting a tumor suppressive role. In addition, the loss of this gene drives castration-resistant prostate cancer. Therefore, our findings support that AR-mediated inhibition of tumor suppressors plays important roles during prostate cancer progression. Our study provides an innovative mechanism for AR in castration resistance, which may eventually lead to novel therapeutic targets for treatment of advanced prostate cancer.

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 LB-273. doi:1538-7445.AM2012-LB-273
Abstract LB-274: Mutant p53 cooperates with ETS2 to promote etoposide resistance
Authors: Martinez Luis A. , Do Phi M. , Varanasi Lakshman
Published: August 2012

Mutant p53 (mtp53) promotes chemotherapy resistance through multiple mechanisms including disabling pro-apoptotic proteins and by regulating gene expression. Analysis of promoter regions identified through CHIP-on-CHIP and CHIP-seq platforms reveal that the ETS motif (EBS) is prevalent within predicted mtp53 binding sites. We demonstrate that mtp53 regulates gene expression through EBS in promoters, and that ETS2 mediates the interaction with this motif. Importantly, we identified TDP2, a 5′-tyrosyl DNA phosphodiesterase involved in the repair of DNA damage caused by etoposide, as a transcriptional target of mtp53. We demonstrate that suppression of TDP2 sensitizes mtp53 expressing cells to etoposide, and that mtp53 and TDP2 are frequently overexpressed in human lung cancer; thus, our analysis identifies a potentially “druggable” component of mtp53's gain-of-function activity.

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 LB-274. doi:1538-7445.AM2012-LB-274
Abstract LB-278: MicroRNA control of GNA13 expression and cancer cell invasion
Authors: Rasheed Suhail Ahmed Kabeer , Teo Cui Rong , Beillard Emmanuel , Voorhoeve P. Mathijs , Casey Patrick
Published: August 2012

Heterotrimeric guanine nucleotide binding proteins (G proteins) transmit a variety of extracellular signals from cell surface G protein-coupled receptors (GPCRs) to intracellular effector molecules. Heterotrimeric G proteins are classified according to the α subunit into four subfamilies: Gs, Gi, Gq, and G12. The G12 subfamily, which is comprised of two members, Gα12 (GNA12) and Gα13 (GNA13), has been implicated in cancer cell invasion and metastasis. G12 signaling promotes prostate, breast and ovarian cancer cell invasion in vitro, and these proteins are highly expressed in metastatic cancer tissues. As part of a program to elucidate the mechanisms by which GNA12 and GNA13 expression is upregulated in cancer cells, we assessed the potential involvement of micro-RNAs (miRNAs) in post-transcriptional control of GNA13 expression. The initial focus was on prostate cancer; LnCAP (with the lowest GNA13 protein level) and PC3 (with the highest GNA13 level) were employed as the model system. Expression analysis of miRNAs predicted to bind the 3′UTR of GNA13 revealed that miR-182 and miR-141/200a showed an inverse correlation to the protein expression in LnCAP and PC3 cells. Ectopic expression of miR-182 and miR-141/200a in PC3 cells significantly reduced mRNA and protein levels, as well as GNA13 3′UTR- reporter activity. Further, expression of these miRNAs significantly inhibited PC3 cell invasion in an in vitro matrigel invasion assay, and this effect was blocked by overexpression of GNA13 in these cells. Importantly, inhibition of miR-182 and miR-141/200a in LnCAP cells using specific miRNA inhibitors (anti-miRs) elevated the expression of GNA13 and enhanced the basal invasion of these cells. These data provide strong evidence that GNA13 expression is regulated by post-transcriptional mechanisms involving miR-182 and miR-200 family members. Further studies are being performed to identify the role of these miRNAs in cancer progression and to determine the importance of impact on GNA13 expression as an important mediator of this effect.

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 LB-278. doi:1538-7445.AM2012-LB-278
Abstract LB-284: Retinoblastoma tumor suppressor protein phosphorylation and inactivation depend on direct interaction with Pin1
Authors: Rizzolio Flavio , Lucchetti Chiara , Caligiuri Isabella , Marchesi Irene , Caputo Mariella , Toffoli Giuseppe , Szanto Andres J. , Bagella Luigi , Castronovo Matteo , Giordano Antonio
Published: August 2012

It is well known that alterations in the pathway controlling pRb phosphorylation account for more than 50% of tumors. Here, we report a striking experimental demonstration that, in cancer cells, pRb phosphorylation by CDK/cyclin proteins depends on Pin1 activity. We propose, for the first time, a detailed mechanism regarding pRb phosphorylation and activity, thereby significantly advancing the basic understanding of cell cycle control. We conclude that at the beginning-middle of G1, CDKs phosphorylate pRb pocket domain, thus allowing its interaction with Pin1. Next, in mid-late G1, the new complex pRb-Pin1 allows CDKs to complete pRb phosphorylation, and therefore allows the expression of S phase entry genes (Cell Death & Differentiation, in press). We believe our finding will have broad implications on target therapy for cancer patients. In fact, cancer cells can inactive pRb by overexpressing only Pin1, without affecting the well-known CDK pathways. Since Pin1 is overexpressed in most tumors, this suggests a new approach to treating cancer patients by utilizing Pin1 inhibitors in combination with or without CDK inhibitors.

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 LB-284. doi:1538-7445.AM2012-LB-284
Abstract LB-285: Regulation of therapy resistance in slow-cycling cancer cells
Authors: Moore Nathan , Chen Amy , Kamionek Michal , Houghton JeanMarie , Lyle Stephen
Published: August 2012

Tumor recurrence after chemotherapy is a major cause of patient morbidity and mortality. Recurrences are thought to be due in part to small subsets of cancer cells that are better able to survive traditional forms of chemotherapy and thus drive tumor re-growth. The ability to isolate and better characterize these therapy-resistant cells is critical for the future development of targeted therapies aimed at achieving more robust and long-lasting responses. Slow-cycling stem cells are integral components of adult epithelial tissues and are required for tissue maintenance. These slow-cycling cells are inherently resistant to traditional forms of chemotherapy that primarily target actively cycling cells. Using a novel application for the proliferation marker CFSE, we have identified populations of slow-cycling, label-retaining cells (LRCs) in primary tumors and cancer cell lines. As predicted, quiescent LRCs exhibit a multi-fold increase in chemoresistance but retain the ability to re-enter the cell cycle. We further demonstrate the innovative application of CFSE to live sort slow-cycling tumor cells and begin to explore the mechanisms behind LRC resistance and survival. Using RT-PCR and immunoblotting, we have observed consistent over-expression of the CDK5 activator, p35, in LRCs of both primary tumor xenografts and in-vitro sphere cultures. While p35 is known to play an active role in neurogenesis, cell migration, and apoptosis within the developing brain, its role in tumor biology remains unclear. Manipulation of p35 expression affects cell cycle distribution, extent of the LRC pool, and cell survival when challenged with traditional forms of chemotherapy. Additionally, we demonstrate that alterations in p35 expression alters downstream CDK5 signaling and the activation state of BCL2. Combined, our data suggest a model whereby the CDK5/p35 complex acts to slow cell cycling speed and change expression of BCL2, promoting resistance to chemotherapy. Future p35 targeting, in combination with traditional forms of chemotherapy, may help to reduce recurrence rates and increase long-term patient survival.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-285. doi:1538-7445.AM2012-LB-285
Abstract LB-291: Role of exosomes in tumor cell adhesion and survival
Authors: Koumangoye Rainelli B.
Published: August 2012

Exosomes are nanovesicles secreted by all living cells. These vesicles are abundant in serum and other extracellular fluids and contain a large repertoire of proteins, mRNA and microRNA. Exosomes have been implicated in cell to cell communication, the transfer of infectious agents, neurodegenerative diseases as well as tumor progression. However, the precise mechanisms by which they are internalized and/or secreted remain poorly understood. In order to follow their release and uptake in breast tumor cells in real time, cell-derived exosomes were tagged with green fluorescent protein (GFP)-CD63. Shown here for the first time is the demonstration that detachment of adherent cells from substratum induces a rapid and substantial secretion of exosomes which then concentrate on the cell surfaces and are re-internalized to mediate adhesion to various extracellular matrix molecules (ECM). In contrast, ECM-immobilized exosomes inhibited cell adhesion and spreading. Disruption of lipid rafts with methyl-beta-cyclodextrin (MβCD) inhibits the internalization of exosomes. Moreover, when short hairpin RNA techniques are used to knockdown lipid raft-interacting proteins AnxA2 and AnxA6, the resultant Anx-depleted breast carcinoma cell lines exhibited decreased exosomes uptake and decreased cellular adhesion. Non-transformed primary breast epithelial cells treated with exosomes induced rapid cell cycle progression, disorganized cellular masses and anoikis resistance in three-dimensional cell culture systems. These data indicate that exosomes contribute to both cancer cell adhesion and survival mechanisms.

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 LB-291. doi:1538-7445.AM2012-LB-291
Abstract LB-292: NANOG promotes chemoresistance in prostate carcinoma cells
Authors: Jiang Hongmei , Wang Man-Tzu , Nie Daotai
Published: August 2012

NANOG promotes chemoresistance in prostate carcinoma cells Hongmei Jiang, Man-Tzu Wang, Daotai Nie The emergence of drug resistant prostate cancer cells is a leading cause of chemotherapy failure in patients with prostate cancer. The mechanisms behind the acquisition of chemoresistance in prostate cancers are, however, poorly understood. NANOG is a transcription factor associated with the self-renewal of embryonic stem cells. Expression of NANOG has been detected in a number of cancer cells, and its expression linked with those positive for stem/progenitor markers. In the present studies, several lines of evidence are presented to suggest that NANOG regulates tumor responses to chemotherapy. First, in the surviving fractions of tumor cells after chemotherapy, there was an elevated level of NANOG expression and activities. Second, prospective enrichment of tumor cells with endogenous NANOG expression led to enrichment of tumor cells resistant to taxol, vinblastine, and doxorubicin. Knockdown of NANOG expression via small hairpin RNAs (shRNAs) sensitized tumor cells toward chemotherapeutics. Real-time PCR array identified an enhanced expression of the ATP-binding cassette efflux transporter B1 (ABCB1) and G2 (ABCG2) in tumor cells enriched with endogenous NANOG expression. Inhibition of ABCB1 activities or knockdown of ABCB1 expression attenuated, but not abolished, the increased resistance in NANOG expressing cells toward taxol and vinblastine. Knockdown of ABCG2 attenuated the resistance of NANOG-expressing tumor cells toward doxorubicin. Together, our results suggest that NANOG confers tumor cells with increased resistance to chemotherapy partially through regulating the expression of ABC transporters.

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 LB-292. doi:1538-7445.AM2012-LB-292
Abstract LB-296: Allikrein 14 induces epithelial-mesenchymal transition-like changes in colon cancer cells
Authors: Darmoul Dalila
Published: August 2012

Accumulating evidence indicates that serine proteinase family of the kallikrein-related-peptidases (KLK1-KLK15) are deregulated in cancer and their up-regulation is often associated with poor patient prognosis. Although primarily known as cancer biomarkers, recent evidence implicates KLKs in many cancer-related processes, including cell-growth, angiogenesis, invasion and metastasis. In addition, KLKs have emerged as signalling molecules by selectively targeting members of a unique subfamily of cell surface G-protein coupled receptors termed, proteinase-activated receptors (PARs). PARs are now considered important players in the development of human colon cancer. Indeed, we have previously demonstrated that in colonic tumours, upregulated PAR-2 and aberrantly expressed PAR-1 and PAR-4 control human colon cancer cell migration and proliferation. Recently, we showed that some members of the aberrantly expressed KLKs mediate these responses by signalling of through PARs. We hypothesized that KLK14 induced-cell migration and colonic tumour invasion are the consequence of epithelial-mesenchymal transition. We focused on KLK14 for which morphological changes were observed when colon cancer cells were treated with KLK14. We found that: 1) microscopic analysis showed redistribution of perijunctional F-actin in KLK14 treated HT29 cells, a colon cancer derived adenocarcinmoma; 2) HT29 cell treatment with KLK14 induced loss of E-cadherin-mediated cell-cell adhesion; 3) Biochemical studies showed down regulation of epithelial markers and upregulation of mesenchymal markers, the molecular mechanisms involved are under investigation. These results suggest for the first time that some KLKs are key mediators of induced ETM in human colonic tumors.

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 LB-296. doi:1538-7445.AM2012-LB-296
Abstract LB-298: EGF induces EMT through PI3K/Akt and MAPK singnaling pathways in breast cancer cell lines
Authors: Kim Jin Kyoung , Kong Jienan , Lee Youngseok , Jeong Hoiseon , Kim Aeree
Published: August 2012

EMT, epithelial-mesenchymal transition, is defined by the loss of epithelial characteristics and the acquisition of mesenchymal properties, such as reduced cell to cell contact, spindle morphology, expression mesenchymal markers and migratory function. In carcinogenesis, EMT is known to be associated with increased aggressiveness, and invasive and metastatic potential. Although various factor, such as EGF signaling pathways, cytokines, miRNAs, Wnt signaling and TGF-ß signaling have been suggested as inducers of EMT signaling pathway, detailed mechanism haven't been clarified except TGF-ß induced EMT. This study was designed to evaluate if and how EGF can induce EMT in breast cancer cell lines. We showed EGF induced EMT, such as elongation of cancer cells, down regulation of E-cadherin, and upregulation of vimentin and fibronectin in MCF-7 and MDA-MB-231 cell lines. In addition, we confirmed that EMT by EGF was induced via MAPK and PI3K/Akt signaling pathway using LY294002 (PI3K inhibitor) and PD98059 (MAPK inhibitor). PI3K inhibitor and MAPK inhibitor also blocked phosphorylation of Smad2 and inhibited nuclear localization of p-Smad2. With using SB203580 (p-Smad2 inhibitor) inhibited expression of Snail. In summary, EGF induces EMT through PI3K/Akt and MAPK signaling pathways, which activate downstream of Smad2 and Sanil signaling in MCF-7 and MDA-MB-231 cell lines.

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 LB-298. doi:1538-7445.AM2012-LB-298
Abstract LB-3: Evidence that dibenzofuran based anti-angiogenic, anti-tumor peptidomimetics target galectin-1
Authors: Dings Ruud P.M. , Miller Michelle C. , Kumar Nigam , Mayo Kevin H.
Published: August 2012

Galectins, named for their selective binding to ß-galactoside-containing glycans, play crucial roles in many physiological as well as pathological processes. Galectin-1 (gal-1) in particular, has been shown to be differentially elevated in tumor endothelial cells in several cancers including cancer of the breast, colon, prostate and ovaries. Gal-1 targeting 33mer peptide, Anginex, inhibits tumor endothelial cell proliferation via anoikis and attenuates tumor angiogenesis and tumor growth. Based on structure-activity relationships of anginex, partial-peptide mimetic were designed, using dibenzofuran (DBF) as a ß-turn mimetic to maintain the two key ß-strands and the bioactive amphipathic ß-sheet conformation of the peptide. The best DBF-based compound 6DBF7 (13mer) inhibited tumor angiogenesis and tumor growth in vivo better than parent anginex. Here we report on the optimization of the anti-angiogenic activity of 6DBF7 analogs in vitro, by substitution of natural and non-natural amino acids, and subsequently the antiangiogenic and anti-tumor effects of the most promising analogs in vivo. In addition, by using NMR spectroscopy and flow cytometry, we demonstrate that the lead 6DBF7 analogs interact with galectin-1 at a site near to its carbohydrate binding domain and by doing so can compete off galectin-1 from binding to ß-galactoside-containing glycans on the surface of cells in vitro. Overall, this research contributes to our ability to design pharmaceutical agents that target galectin-1 and thereby inhibit tumor growth and are potentially clinical candidates for use in the management of human cancers. This work was supported by NIH grant CA096090 to KHM

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 LB-3. doi:1538-7445.AM2012-LB-3
Abstract LB-30: A functional analysis of the nuclear RhoGEF Ect2 in ovarian cancer
Authors: DeCristo Molly J. , Parker Lauren E. , Trembath Dimitri , Kuan Pei-Fen , Yim Margaret , Liu Jinsong , Miller C. Ryan , Der Channing J. , Cox Adrienne D.
Published: August 2012

Ect2 is a guanine nucleotide exchange factor (GEF) and activator of Rho family small GTPases. Ect2 regulates RhoA, Rac1, and Cdc42, thereby playing an important role in the control of cell proliferation, survival, and migration. Originally identified as an oncogene in vitro, the role of Ect2 in regulating migration makes it of particular interest in ovarian cancer, in which local invasion and ascites are prevalent. Notably, ECT2 is located on 3q26.1-3q26.2, the most frequent amplicon in ovarian cancer, and it has been found to be overexpressed at the mRNA level in ovarian tumors. We first explored the role of Ect2 in ovarian cancer by knocking it down using shRNA and assessing anchorage-independent growth and both random and directed migration in a panel of ovarian cancer cell lines. Our findings reveal that Ect2 expression is required for each of these functions. Interestingly, we found that Ect2 utilization of specific Rho GTPase substrates is highly context-dependent. In addition, to investigate the potential clinical importance of Ect2, we studied its expression and localization in primary epithelial ovarian cancers, using over 300 histological tumor and cyst samples incorporated into a tissue microarray (TMA). Ect2 is unusual among the RhoGEFs because of its localization. A critical regulator of cytokinesis, it is sequestered to the nucleus in interphase cells. It has been hypothesized that the overexpression and mislocalization of Ect2 into the cytoplasm leads to aberrant Rho activation and oncogenesis. Unexpectedly, our recently completed TMA data analysis suggests that malignant serous ovarian cancer is instead associated with nuclear Ect2, while benign disease is associated with mislocalized, cytosolic Ect2. We are currently exploring a possible nuclear mechanism to explain these findings. Although standard immunohistochemical analyses typically report only total protein levels, our new data reveal that unrestricted subcellular localization of Ect2 is likely to be more important than total protein levels for ovarian pathology.

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 LB-30. doi:1538-7445.AM2012-LB-30
Abstract LB-427: TAK1 (MAP3K7) inhibition promotes apoptosis in KRAS dependent colon cancers
Authors: Singh Anurag , Sweeney Michael F. , Yu Min , Burger Alexa , Greninger Patricia , Benes Cyril , Haber Daniel A. , Settleman Jeff
Published: August 2012

Colon cancers frequently harbor KRAS mutations, yet only a subset of KRAS-mutant colon cancer cell lines are dependent upon KRAS signaling for survival. In a screen for kinases that promote survival of KRAS-dependent colon cancer cells, we found that the TAK1 kinase (MAP3K7) is required for tumor cell viability. The induction of apoptosis by RNAi-mediated depletion or pharmacologic inhibition of TAK1 is linked to its suppression of hyperactivated Wnt signaling, evident in both endogenous and genetically reconstituted cells. In APC-mutant/KRAS-dependent cells, KRAS stimulates BMP-7 secretion and BMP signaling, leading to TAK1 activation and enhancement of Wnt-dependent transcription. An in vitro-derived “TAK1-dependency signature” is enriched in primary human colon cancers with mutations in both APC and KRAS, suggesting potential clinical utility in stratifying patient populations. Together, these findings identify TAK1 inhibition as a potential therapeutic strategy for a treatment-refractory subset of colon cancers exhibiting aberrant KRAS and Wnt pathway activation.

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 LB-427. doi:1538-7445.AM2012-LB-427
Abstract LB-44: Sister to sister
Authors: Whaley Lori A.
Published: August 2012

Mission Statement: To empower the minority community to take a more active role in meeting their health needs. Goals: To educate African American women & families about the importance of early detection of breast cancer, breast self-exam (BSE), clinical breast exam (CBE) and mammograms; to inspire and recruit survivors to participate in Women In Touch (WIT); to educate and gain the trust of minority women about enrolling in clinicals trials. Our Services: Wig bank, protheses, transportation, health care symposium, presentations at churches or civic groups, support group meetings, quarterly newsletters and financial assistance referrals.

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 LB-44. doi:1538-7445.AM2012-LB-44