bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract LB-275: Genome-wide analysis of the vitamin D receptor (VDR) binding sites reveals vitamin D role mediating autophagy in luminal-like breast cancer cells
Authors: Tavera Luz E. , Westerling Thomas , Brown Myles
Published: August 2012

The active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25D3), regulates gene expression through the vitamin D receptor (VDR). Even though 1,25D3 is still best known as a regulator of bodily calcium homeostasis, 1,25D3 has a plethora of physiological actions which include immune and nervous system modulation, cellular proliferation and differentiation. Epidemiological and model studies have revealed the cancer-protective properties of 1,25D3 in colon, prostate and notably in breast. We are actively investigating the anti-proliferative properties of 1,25D3 in a panel of human breast cancer cell lines. We found that 1,25D3 induces autophagy in several luminal-like breast cancer cell models, but not in basal-like or mesenchymal-like models. We performed VDR and signaling partner RXR whole-genome ChIP-seq analysis to uncover all of the direct 1,25D3 target genes involved in regulation of metabolism and autophagy. Our preliminary studies suggest that energy regulation as an important aspect of 1,25D3 anti-proliferative properties in luminal-like breast cancer cells

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-275. doi:1538-7445.AM2012-LB-275
Abstract LB-276: 2-D DIGE and siRNA to find new cancer targets
Authors: Jorsback Anneli , Winkvist Maria , Hagner-McWhirter Åsa , Landström Marene , Sundar Reshma , Engström Ulla
Published: August 2012

siRNA is a powerful tool in loss-of-function studies which generates valuable information on target validation. siRNA is highly selective and suppress gene expression in a sequence-specific manner. These features have made it a key tool in signal transduction - a cornerstone in cancer biology. 2-D DIGE (two dimensional differential gel electrophoresis) is a fluorescence based technology with the capacity to separate thousands of proteins in one single run, with high reproducibility. This makes it a valuable tool for differential expression analyses. In this study two powerful methods, siRNA and 2-D DIGE, were combined to investigate a well-known signaling pathway, pivotal in cancer biology. Silencing of the target protein made it possible not only to identify a large number of proteins that were differentially regulated but also to resolve the time dependency of protein regulation. Thus the combined use of siRNA and 2-D DIGE made it possible to find potentially new targets in the 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-276. doi:1538-7445.AM2012-LB-276
Abstract LB-277: Global translational regulation by miR-520c
Authors: Mazan-Mamczarz Krystyna , Zhao Frank , Dai Bojie , Steinhardt James , Gartenhaus Ronald B.
Published: August 2012

MicroRNAs (miRNAs) are endogenous small non-protein-coding RNAs that control a variety of cellular processes by modulating protein expression. Many studies have focused on the role of microRNAs in cancer development and age-related diseases, but the cellular mechanisms by which microRNAs influence aberrant cell growth are still poorly understood. We found that overexpression of a miR-520c-3p precursor decreased global gene translation, and induced senescence as measured by monitoring beta-galactosidase activity and other senescence markers. To better understand the mechanisms underlying miR-520c-3p mediated global translational repression, we performed translational profiling of mRNA isolated from polysomal fractions. We identified subsets of cancer-related genes with repressed translation after overexpression of miR-520c-3p. Interestingly, among them we found eukaryotic translation initiation factor 4 gamma 3 (eIF4G3), a key component of the cap-dependent translation regulation complex (eIF4F). While increases in miR-520c-3p did not change eIF4G3 mRNA abundance, there was a significant reduction in eIF4G3 protein synthesis. The specific repressive influence of miR-520c-3p on eIF4G3 was confirmed by employing heterologous reporter constructs bearing the 3′ untranslated region (3′UTR) of eIF4G3 mRNA. In addition, either miR-520c-3p overexpression or eIF4G3 knockdown, led to decreased eIF4E association with the translation initiation complex as measured by 7-methyl-GTP cap analog pull down, and diminished colony formation in lymphoma cells, as assessed by clonogenic assays. Finally, our findings that, diffuse large B cell lymphoma (DLBCL) cells express low levels of miR-520c-3p with reciprocally high eIF4G3 protein levels, and that TMA analysis revealed significantly higher eIF4G3 expression in patient DLBCL samples compared to normal GCB cells, supports the role of these molecules in the dysregulation of protein synthesis present in NHL. In summary, we demonstrated that overexpression of mir-520c-3p can suppress tumor growth by decreasing global protein translation and inducing senescence in DLBCL cells, and that miR-520c-3p elicits these actions by repressing eIF4G3 expression. Repressed global gene translation and premature senescence blocks cell proliferation, and together function as tumor suppressor mechanisms. Therefore, inhibition of translation and induction of senescence by miRNAs and/or small molecule inhibitors that target eIF4G3 is an innovative strategy for lymphoma therapy.

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-277. doi:1538-7445.AM2012-LB-277
Abstract LB-279: SIRT6 expression is regulated by cAMP signaling system in non small cell lung cancer cells
Authors: Kim Eui-Jun , Juhnn Yong-Sung
Published: August 2012

Sirtuin 6 (SIRT6) is a member of the NAD+ dependent histone deacetylase (HDAC) family. HDACs play an important role in epigenetic regulation of gene expression, which is counteracted by histone acetyl-transferase (HAT). HDACs remove acetyl-group at lysine residue of histone tail, and change the conformation of chromatin complex, which eventually regulates transcription activity in of various cancer cells. SIRT6 is reported to be a site specific deacetylase acting at histone H3K9 and H3K56, but very few studies on the regulation of SIRT6 expression have been reported. Cyclic AMP (cAMP) signaling system regulates a variety of cellular responses including metabolism, gene expression, proliferation and death. Therefore, we studied the effect of cAMP signaling system on the expression of SIRT6 and its underlying mechanism in lung cancer cells. Stimulatory heterotrimeric GTP-binding proteins (Gαs) are activated by various ligand-bound receptors and stimulate adenylate cyclase to activate cAMP signaling system. Expression of constitutive active Gαs (GαsQL) decreased SIRT6 protein level without change in its mRNA level in H1299 lung cancer cells. GαsQL expression accelerated proteasomal degradation of SIRT6, resulting in a decreased half-life of the protein from 2.2 h to 1.2 h. SIRT6 expression was also decreased by forskolin (adenylate cyclase activator), but increased by H89 (PKA inhibitor). These results indicate that cAMP signaling system decreases SIRT6 expression by accelerating proteasomal degradation of SIRT6 expression via PKA-dependent pathway in lung cancer cells. This finding suggests that cAMP signaling system can contribute epigenetic regulation of cancer-related gene expression by modifying SIRT6 expression.

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-279. doi:1538-7445.AM2012-LB-279
Abstract LB-28: A co-op of EGFR and EphA4 promotes the progression of NSCLC through EGF-Grb7-Stat3 mediated transcriptional regulation of EphA4 gene expression
Authors: Chu Pei-Yu , Li Tsai-Kun , Chou Kai-Ming , Shen Tang-Long
Published: August 2012

Growth factor receptor bound protein-7 (Grb7) regulates diverse cellular functions as a result of its multi-domain functionality in protein-protein interactions. A number of reports have indicated that Grb7 is essential for EGFR-mediated tumorigenesis and cancer progression. However, it remains unclear how Grb7 potentiates tumor progression. To understand the underlying mechanisms by which Grb7 participates in EGFR-mediated tumorigenesis, we utilized microarray analyses and yeast two-hybrid screening to explore Grb7-mediated signaling. Of which, a migration related protein, EphA4, was markedly up-regulated in associated with Grb7 overexpression but down-regulated while knocking down Grb7. Eventually, in response to EGF stimulation, we found that Grb7 was trans-located into the nucleus from the cytoplasm, which in turn promoted STAT3 transcriptional activity on EphA4 gene expression. The significance of this finding is further highlighted by the co-upregulation of Grb7 and EphA4 is concurrent with the highly invasive capability of lung adenocarcinoma. Moreover, we found that EphA4 could also potentiate EGF-induced reorganization of cytoskeleton, ERK1/2 phosphorylation, and cancer cell functions such as proliferation, migration and anchorage-independent growth. Based on these findings, we hypothesize that EphA4 can act as an amplifier involved EGF-mediated cancer progression in an EGF/Grb7/Stat3-mediated transcriptional manner. This study reveals a novel mechanism by which Grb7 regulates tumor progression through the EGF- by triggering EphA4 expression and then prolonging EGFR signaling in regulation of diverse cellular functions involved in cancer progression, thereby highlighting the potential strategy to target Grb7 for anti-cancer therapy.

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-28. doi:1538-7445.AM2012-LB-28
Abstract LB-280: RNP biogenesis factor Thoc1 is targeted for ubiquitination by NEDD4-1 E3 ligase
Authors: Song Fei , Fan Chuandong , Zhang Xiaojing , Wang Xinjiang , Goodrich David W.
Published: August 2012

Thoc1 encodes an essential protein component (pThoc1) of the THO complex that regulates the packaging of nascent transcripts into ribonucleoprotein complexes (RNPs). Loss of pThoc1 compromises transcriptional elongation, RNA processing, and RNA export. Up-regulation of pThoc1 expression is common in a number of different cancers relative to normal tissue (Guo et al., 2005, Yang et al., 2008) and Thoc1 is preferentially required by neoplastic cells for growth and viability (Li et al., 2007). It is unclear how Thoc1 protein or the THO complex is normally regulated. In this study we examined whether pThoc1 is modified and regulated by ubiquitination because it is a low abundant protein in normal tissue. We found that both endogenous and ectopically expressed pThoc1 are polyubiquitinylated in Hela cells. Importantly, we identified that NEDD4-1 (neural precursor cell expressed developmentally down-regulated protein 4) is an E3 ligase that can mediate pThoc1 ubiquitination. This conclusion was reached based on several lines of evidence. First, overexpression of wild type but not the enzyme-dead NEDD4-1 increased pThoc1 ubiquitination. Second, pThoc1 ubiquitination was significantly reduced in Nedd4 knock out murine embryonic fibroblasts (MEFs) compared to the wild type MEFs. Third, inducible knockdown of NEDD4-1 expression in HeLa cells caused significant reduction in pThoc1 ubiquitination. These results indicate that pThoc1 is a novel substrate of NEDD4-1 E3 ligase in cells. Regulation of pThoc1 functions by NEDD4-1 mediated ubiquitination merits further investigation. This study was supported by grant # NIH R01 CA125665

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-280. doi:1538-7445.AM2012-LB-280
Abstract LB-282: Myxovirus (influenza virus) resistance 1 (MX1) polymorphism in prostate cancer
Authors: Glymph Shanora , Mandal Sanjay , Evans Ashley , Chaudhary Jaideep
Published: August 2012

PURPOSE: Myxovirus (influenza virus) resistance 1 (MX1) is an interferon regulated gene responsible for a specific antiviral state against viral infection. We have previously shown that MX1 is up-regulated by androgens in the normal prostate epithelial cells; however, there is no known role for MX1 in cancer. Meta-analysis of different expression databases e.g. NCBI GEO and Oncomine suggested a strong inverse association between MX1 expression and prostate cancer. To confirm these studies, we performed Immunohistochemistry on normal prostate and prostate cancer tissues. Our data revealed that MX1 expression was indeed decreased in PCa as compared to normal, indicating that MX1 could be transcriptionally down-regulated. Literature studies indicated that MX1 down-regulation could be due to a specific polymorphism in the proximal MX1 promoter. In the promoter region of MX1 at position -88, a single nucleotide polymorphism G>T (rs2071430) is involved in modifying the gene expression. Interestingly, the rs2071430 harbors an interferon-stimulated response element (ISRE) that is required for MX1 expression in response to interferons. The “T” allele restores whereas the “G” allele attenuates ISRE binding resulting in increased or decreased MX1 expression respectively. Based on these observations we hypothesized that decreased expression of MX1 in prostate cancer could be due to the rs2071430 polymorphism. DESIGN METHODS: We investigated MX1 rs2071430 polymorphism in genomic DNA from equal number of disease free and prostate cancer samples (N=305). The sample size required to achieve statistically significant associations were calculated using the power calculator for case control genetic association studies. Polymorphism was detected by sequencing the PCR amplicon through SNPdetector to ensure that the SNP was due to heterozygous allelic variations and not due to sequencing artifacts. RESULTS: The data suggests that the GG genotype (low promoter activity) is higher in PCa (72%) as compared to normal (58.6%). The TT genotype (high activity) was higher in normal (5.7%) compared to PCa (2.4%). No TT genotype was observed in Caucasian normal samples. The results were statistically significant at P<0.05. Our results, for the first time demonstrate that MX1 is down-regulated in prostate cancer possibly at the transcriptional level due to ISRE polymorphism in the promoter region. ACKNOWLEDGEMENTS: This research is supported by NIH/NCMHD grant 1P20MD002285-01.

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-282. doi:1538-7445.AM2012-LB-282
Abstract LB-286: 3p24 tumor suppressor gene RBMS3 in NPC
Authors: Chen Juan
Published: August 2012

Deletion within the 3p chromosomal region are one of the most frequent genetic alterations in many solid tumors, including nasopharyngeal carcinoma (NPC), suggesting the existence of one or more tumor suppressor genes (TSGs) within the frequently deleted region. A putative TSG RBMS3, located at the frequently deleted region 3p24-p23, has been identified in our previous study. Here, we reported that down-regulation of RBMS3 was detected in 3/3 (100%) NPC cell lines and 13/15 (86.7%) primary NPC tissues. Functional analysis demonstrated that RBMS3 was able to suppress tumorigenicity of NPC cells both in vitro and in vivo, including inhibiting the cell growth rate, colony formation in vitro and tumor formation in nude mice. Additionally, the tumor suppressive mechanism of RBMS3 was associated with its role in cell cycle arrest at the G1/S checkpoint by the up-regulation of p53, and p21, the down-regulation of Smad4, cyclin D1, cyclin E/CDK2, and the subsequent inhibition of Rb-ser780. Further analysis demonstrated that RBMS3 had a pro-apoptotic role in a mitochondrial-dependent manner via activation of caspase-9 and PARP. Finally, RBMS3 inhibited microvessel formation, which may be mediated by down-regulation of β-catenin and inactivation of its downstream targets, including c-Myc, MMP7, MMP9, and MMP2. Taken together, our findings define a function for RBMS3 as an important tumor suppressor gene in NPC.

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-286. doi:1538-7445.AM2012-LB-286
Abstract LB-287: TPX2 acts as a scaffold and co-activator protein for the oncogenic kinase Aurora B
Authors: Iyer Jyoti , Tsai Ming-Ying
Published: August 2012

Aurora B kinase is a master regulator of mitosis and is over-expressed in a variety of malignancies including astrocytomas, seminomas, ependymomas, prostate cancer and non small-cell lung cancer. Several Aurora B inhibitors are currently being evaluated for their efficacy in cancer therapy. Therefore, it is critical to understand the regulation of Aurora B activity by other proteins. Aurora B forms the enzymatic core of the Chromosomal Passenger Complex (CPC). The CPC consists of three other proteins besides Aurora B: INCENP, Survivin and Borealin. All these proteins have been known to promote Aurora B activation. The mitotic protein Targeting Protein for Xenopus kinesin-like protein 2 (TPX2) co-localizes with Aurora B at several stages of mitosis, hinting at the existence of a signaling cross-talk between Aurora B and TPX2. The main purpose of our study is to determine whether Aurora B and TPX2 can cross-talk with each other during mitosis, and if found so, to decode the mechanism by which this signaling cross-talk occurs. We hypothesize that TPX2 can transmit signals to regulate Aurora B activity during mitosis. To test our hypothesis, we have performed experiments utilizing M-phase Xenopus egg extracts (XEE) which possess an abundance of mitotic proteins, and human cell lines as model systems. By performing immunoprecipitation assays (IPs) in M-phase XEE, we detected an interaction between TPX2 and the CPC proteins - Aurora B, INCENP and Survivin. This validates the existence of a signaling cross-talk between TPX2 and the CPC proteins. Moreover, IPs and microtubule pelleting assays utilizing XEE revealed that, as is typical of scaffold proteins, either too much or too little TPX2 alters Aurora B activity. Significantly, immunodepletion of endogenous TPX2 from XEE decreases the association between Aurora B and its activators- Survivin and INCENP, leading to a consequent reduction in Aurora B activity. Additionally, in vitro binding assays demonstrate that, residues 138 to 328 of Xenopus TPX2 (TPX2 B) are sufficient to enhance the interaction between Aurora B and its activator, Survivin. Further, TPX2 B also increases Aurora B kinase activity in an in vitro kinase assay. These data suggest that under endogenous conditions, TPX2 functions as a co-activator of Aurora B by increasing Aurora B-Survivin and Aurora B-INCENP interactions. Importantly, IPs with Panc-1 and CFPAC-1 pancreatic cancer cell lines suggest that this mechanism of Aurora B activation by TPX2 is likely to be conserved in human cancer cell lines. Based upon our results, we conclude that TPX2 enhances Aurora B activity by serving as a scaffold protein for assembly of the CPC.

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-287. doi:1538-7445.AM2012-LB-287
Abstract LB-289: A novel role for the p19ARF tumor suppressor in chromosome segregation
Authors: Britigan Eric MC , Weaver Beth A.
Published: August 2012

The p19ARF tumor suppressor (p14ARF in humans) is part of the ink4a locus and has been implicated in a variety of cancers. The traditional role for p19ARF has been in the stabilization of p53, a protein which is inactivated or mutated in 50% of tumors. However, it has been suggested that p19ARF has roles outside of this pathway. Evidence for this comes from mouse model studies that found mice lacking p19ARF and p53 develop a wider tumor spectrum and are more likely to have multiple tumors than mice lacking p53 alone. We have found that loss of p19ARF in mouse embryonic fibroblasts (MEFs) leads to a weakened mitotic checkpoint and aneuploidy. The mitotic checkpoint is the major cell cycle checkpoint regulating chromosome segregation and progression through mitosis. Defects in chromosome segregation produce progeny that are aneuploid, meaning they contain an abnormal chromosome number that deviates from a multiple of the haploid. The majority of cancers are aneuploid, which suggests that a dysfunctional mitotic checkpoint could play a role in tumorigenesis or cancer progression. In addition to a weakened mitotic checkpoint, loss of p19ARF leads to other mitotic defects including multipolar spindles, supernumerary centrosomes, and lagging chromosomes in anaphase. Future work will define the mechanism by which p19ARF functions in mitosis and establish an additional role in which p19ARF acts as a tumor suppressor.

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-289. doi:1538-7445.AM2012-LB-289
Abstract LB-29: LKB1 tumor suppressor regulates AMP kinase/mTOR-independent cell growth and proliferation via the phosphorylation of Yap
Authors: Nguyen Hoa B. , Babcock Justin T. , Wells Clark D. , Quilliam Lawrence A.
Published: August 2012

The liver kinase B1 (LKB1) tumor suppressor inhibits cell growth through its regulation of cellular metabolism and apical-basal polarity. The best understood mechanism whereby LKB1 limits cell growth is through activation of the AMP-activated-protein-kinase/mammalian-target-of-rapamycin (AMPK/mTOR) pathway to control metabolism. Since LKB1 is also required for polarized epithelial cells to resist hyperplasia it is anticipated to function through additional mechanisms. Recently, Yes-associated protein (Yap) has emerged as a transcriptional co-activator that modulates tissue homeostasis in response to cell-cell contact. Thus this study examines a possible connection between Yap and LKB1. Restoration of LKB1 expression in HeLa cells, which lack this tumor suppressor, or shRNA knockdown of LKB1 in 293T cells, demonstrated that LKB1 promotes Yap phosphorylation, nuclear exclusion, and proteasomal degradation. The ability of phosphorylation-defective Yap mutants to rescue LKB1 phenotypes, such as reduced cell proliferation and cell size, suggest that Yap inhibition contributes to LKB1 tumor suppressor function(s). Interestingly, LKB1 inhibited Yap independently of either AMPK or mTOR activation. These findings reveal a novel mechanism whereby LKB1 may restrict cancer cell growth via the inhibition of Yap.

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-29. doi:1538-7445.AM2012-LB-29
Abstract LB-293: High-throughput proteomic analysis identifies protein s as a modulator of high grade and castrate-resistant prostate cancer
Authors: Saraon Punit , Jarvi Keith , Diamandis Eleftherios P.
Published: August 2012

High-Throughput Proteomic Analysis Identifies Protein S as a Potential Modulator of Castrate-Resistant Prostate Cancer Punit Saraon, Daniela Cretu, Colm Morrissey, Keith Jarvi, Eleftherios P. Diamandis Androgen-deprivation remains the principal therapy for advanced and metastatic prostate cancers. However, some cancer cells can survive this treatment and transform themselves to a more aggressive androgen-independent prostate cancer (AIPC). An understanding of the molecular alterations that occur during the progression to androgen-independence is an integral step to generate effective targeted therapies. Using Mass Spectrometry, we compared the proteomes of androgen independent cell lines (PC3, DU145, PPC1, LNCaP-SF, 22Rv1) to androgen-dependent (LNCaP, VCaP) and normal prostate epithelial (RWPE) cell lines. We identified more than 100 proteins that were differentially secreted in the androgen independent cell lines, based on spectral counts. Of these, Protein S (PROS1) was elevated in the secretomes of all of the AIPC cell lines, with no detectable secretions in normal and androgen dependent cell lines. Using qPCR, we observed significantly higher tissue expression levels of PROS1 in prostate cancer samples (p<0.05), further indicating its importance in prostate cancer progression. Similarly, immunohistochemistry analysis revealed elevation of PROS1 during high grade prostate cancer (Gleason ≥ 8), and further elevation in castrate-resistant metastatic prostate cancer lesions. We also observed its elevation in high grade prostate cancer seminal plasma samples (P<0.05). To understand the functional role of PROS1 with respect to prostate cancer progression, we generated stable PROS1 knock-downs in DU145 cells, and performed cell migration and viability assays. In-vitro scratch assays measuring cell migration and proliferation revealed that PROS1 enhanced growth of prostate cancer cells, as there was significantly reduced wound closure in shPROS1 DU145 cells compared to scrambled control cells (p<0.05). In addition, cell viability assays showed that shPROS1 cells had reduced survival rates compared to scrambled cells when treated with the chemotherapeutic agents, docetaxel and paclitaxel, indicating its role as a potential anti-apoptotic factor. Taken together, our preliminary results show that PROS1 is elevated during high grade and castrate-resistant prostate cancer, and promotes prostate cancer migration and cell 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-293. doi:1538-7445.AM2012-LB-293
Abstract LB-299: Prognostic impact of EMT (epithelial-mesenchymal-transition) related protein expression in endometrial cancer
Authors: Tanaka Yoshimichi
Published: August 2012

Objectives: Epithelial-mesenchymal-transition (EMT) is recently identified as a important step in the invasion and metastasis of cancer. In this process, a critical molecular feature is the down regulation of E-cadherin and which is controled mainly by the Snail-related zinc-finger transcription factors (Snail and Slug). The aim of this study is to evaluate the prognostic impact of EMT related protein (E-cadherin, Snail and Slug) expression in endometrial cancer. Methods: We perfomed immunohistochemical annalysis using tissue microarray samples of 354 primary tumors and 30 metastases of endometrial carcinomas, and investigated the relationship between protein expression, clinicopathologic features and outcomes. Results: Reduced E-cadherin was seen in 39.8% in primary tumors. In endometrioid adenocarcinoma, reduced E-cadherin was seen in 19.5%, 40.8% and 72.7% in G1, G2 and G3 tumors, respectively. Nuclere expression of Snail was positive in 16.9% in primary tumors. Both redeced E-cadherin and nuclear expression of Snail were significantly associated with histological type, FIGO stage, myometrial invasion, ascites positive, lymph node metastasis and patient survival (P<0.01). Nuclear expression of Slug was seen in only 3.7% in primary tumors. Allmost all cases of Slug positive were carcinosarcomas, therefore, it was also associated with patient survival (P<0.01). We couldn't find any differencies in the rates of reduced E-cadherin and nuclear expression of Snail/Slug between in the primary tumors and metastases. In multivariate analysis, nuclear expression of Snail or Slug was found to be a significant predictor for both the progression free survival and overall survival (P<0.01). Conclusions: These data indicate that reduced E-cadherin and nuclear expression of Snail and Slug have a prognositic impact in endometrial cancer. Therefor, to clarify and control of EMT signaling is a promising molecular targeting therapy in endometrial 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-299. doi:1538-7445.AM2012-LB-299
Abstract LB-300: The role of WNT7B in prostate cancer bone metastasis
Authors: Zheng Dali , Zhou Tianhua , Decker Keith F. , Wang Kaidi , Jia Li
Published: August 2012

Prostate cancer is the most common cancer for men in the US. It is well known that the androgen receptor (AR), a master transcription factor in prostate, plays a critical role in all stages of prostate cancer. There has been a dedicated interest in identification of downstream AR target genes responsible for prostate cancer growth and progression. Using chromatin immunoprecipitation sequencing (ChIP-seq) and RNA sequencing (RNA-seq), we identified WNT7B as a direct AR target gene in both androgen-dependent LNCaP and androgen-independent C4-2B cells. Knockdown of WNT7B by RNA interference inhibits the growth of LNCaP and C42B cells, accompanied by a corresponding increase in apoptosis as determined by Caspase-3 and -7 activities. Overexpression of WNT7B promotes the growth of C4-2B cells in the absence of androgen. One of the major challenges in prostate cancer research is the propensity for bone metastasis, which displays characteristic osteoblastic lesions. Since WNT7B plays an important role in bone formation, we asked whether prostate cancer-produced WNT7B induces osteoblast differentiation using an in vitro model of the murine osteoblast precursor ST2 cell line. We found that in a co-culture system, overexpression of WNT7B in LNCaP and C42B cells induces osteoblastic differentiation of ST2 cells, as indicated by increased alkaline phosphatase production, bone sialoprotein (an early marker for osteoblast differentiation) expression, and mineralization. On the other hand, knockdown of WNT7B in prostate cancer cells inhibits the differentiation of ST2 cells. These results indicate that WNT7B can stimulate the growth of prostate cancer cells as an autocrine agent and induce osteoblastic differentiation in bone metastases as a paracrine agent. WNT7B may be a potential therapeutic target for prostate cancer bone metastasis.

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-300. doi:1538-7445.AM2012-LB-300
Abstract LB-301: Galectin-3 contributes to melanoma metastasis by regulating Autotaxin through NFAT1
Authors: Braeuer Russell R. , Zigler Maya , Kamiya Takafumi , Dobroff Andrey S. , Huang Li , Bar-Eli Menashe
Published: August 2012

Melanoma is the deadliest form of skin cancer in which patients with metastatic disease have a five year survival-rate of less than 10%. Recently the over expression of a beta galactoside binding protein, Galectin-3, has been correlated with metastatic melanoma. Yet its role in melanoma progression is not completely understood. We have previously demonstrated that silencing Galectin-3 in melanoma cell lines leads to decreased melanoma cell invasion and migration in vitro and inhibits tumor growth and metastasis in vivo via the regulation of VE-cadherin and IL-8. To determine whether Galectin-3 can enhance the expression of other genes involved in the metastatic phenotype, a cDNA microarray analysis was performed after silencing Galectin-3 in melanoma cell lines. One of the many genes down regulated after silencing Galectin-3 is the lysophospholipase D enzyme Autotaxin. Autotaxin expression enhances melanoma migration and invasion by converting Lysophosphatidylcholine (LPC) to Lysophosphatidic acid (LPA) within the tumor microenvironment. LPA binds to EDG family G-protein coupled receptors to initiate downstream signaling which drives invasion and metastasis. Here we show that Galectin-3 regulates Autotaxin expression at the transcriptional level. Moreover, silencing Galectin-3 decreases total protein expression of the transcription factor NFAT1 which reduces its binding to the Autotaxin promoter. This in turn decreases Autotaxin promoter activity and protein expression. Therefore, Galectin-3 is required to maintain NFAT1 protein expression which enhances Autotaxin transcription and induces angiogenesis, tumor growth, and metastasis of melanoma cells. This is the first report to connect Galectin-3 with Autotaxin and LPA synthesis along with assigning an important role for NFAT1 in melanoma metastasis.

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-301. doi:1538-7445.AM2012-LB-301
Abstract LB-302: Coordinate upregulation of pluripotency factors in a hybrid epithelial/mesenchymal state in anoikis resistant suspended breast epithelial cells
Authors: Grosse-Wilde Anne , Ozinsky Adrian
Published: August 2012

Epithelial cells have an absolute requirement for surface adhesion for survival, and loss of adhesion activates apoptosis, a process named anoikis. During metastasis, cancerous epithelial cells are able to survive anoikis after they have spread from the primary site of the tumor. The mechanisms underlying anoikis survival are not well understood, but include cell lineage switching from epithelial to mesenchymal behavior, implying a role for stem cells. Several studies have shown that the mesenchymal population of tumorigenic breast cells contains stem cells, yet it appears that only a small yet unknown subpopulation of the mesenchymal cells is able to survive the strong selection pressure to survive anoikis in suspension and proliferate to form mammospheres. These studies have been complicated by the fact that heterogeneous cell lines consisting of epithelial and mesenchymal cells were analyzed, obscuring the role of small but possibly relevant subpopulations. Here, we were employing both single cell-derived homogeneous mesenchymal cell clones as well as novel microfluidics-based high throughput qRT-PCR analysis to unravel gene expression in epithelial and/or mesenchymal breast cancer cells during survival of anoikis. We show evidence that during culture of transformed mammary epithelial cells (HMLER) in suspension certain subpopulations disappear and then get repopulated by the surviving, proliferating and differentiating subpopulation in suspension. During this period in suspension critical for repopulation we find coordinate expression of both epithelial and mesenchymal markers, rapid upregulation of pluripotency factors (such as OCT4 and Nanog), as well as of several other genes that have previously been described to indicate poor prognosis for breast cancer survival. Those poor prognosis markers we also found elevated in replated and passaged anoikis-resistant HMLER cells as well as in HMLER-derived mesenchymal clones. By contrast expression of pluripotency factors was only restricted to the suspended state. In conclusion, here we show that in suspended breast epithelial cells there exists an epithelial/mesenchymal hybrid state likely to give rise to differentiated progenies, being able to adapt to the diverse challenging environments such as at secondary metastatic sites in 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 LB-302. doi:1538-7445.AM2012-LB-302
Abstract LB-303: Metastasis suppression by MDM2 binding protein through inhibition of ACTN4 function
Authors: Iwakuma Tomoo
Published: August 2012

MDM2 Binding Protein (MTBP) has been implicated in cancer progression. Our previous results demonstrate that MTBP haploinsufficiency in mice enhances cancer metastasis. Recently, loss of MTBP expression is shown to be associated with reduced survival of patients with head and neck carcinoma, and serves as an independent prognostic factor when p53 is mutated in tumors. Here we demonstrate one mechanism by which MTBP inhibits cancer metastasis. Overexpression of MTBP in human osteosarcoma cell lines lacking wild-type p53 did not alter primary tumor growth in mice but significantly inhibited metastases. MTBP downregulation increased the migratory potential of Mdm2-/-p53-/- mouse embryonic fibroblasts, suggesting that MTBP inhibited cell migration independently of the MDM2-p53 pathway. Co-immunoprecipitation and mass spectrometric analysis identified alpha-actinin-4 (ACTN4) as a MTBP-interacting protein. Endogenous MTBP interacted with and partially colocalized with ACTN4. MTBP overexpression inhibited cell migration and filopodia formation mediated by ACTN4. Increased cell migration by MTBP downregulation was inhibited by concomitant downregulation of ACTN4. MTBP also inhibited ACTN4-mediated F-actin bundling. We furthermore demonstrated that nuclear localization of MTBP was dispensable for inhibiting ACTN4-mediated cell migration and filopodia formation. Thus, MTBP suppresses cell migration, at least partially, by inhibiting ACTN4 function. Our study not only provides a mechanism of metastasis suppression by MTBP, but also suggests MTBP as a potential biomarker for cancer progression.

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-303. doi:1538-7445.AM2012-LB-303
Abstract LB-304: Sp1 expression regulates lung tumor progression
Authors: Hsu Tsung-I , Hung Jan-Jong
Published: August 2012

The role of Sp1 in controlling gene expression in lung tumor development and metastasis is not well understood. In this study, we showed that the Sp1 level was highly increased and required for lung tumor growth in transgenic mice bearing Kras-induced lung tumors under the control of doxycycline. Furthermore, the Sp1 level was highly upregulated in lung adenocarcinoma cells with low invasiveness and in patients with stage I lung cancer. We also demonstrated that Sp1 was downregulated in lung adenocarcinoma cells with high invasiveness and in patients with stage IV lung adenocarcinoma. Moreover, Sp1 inversely regulated migration, invasion and metastasis of lung adenocarcinoma cells in vivo. In addition, a decrease in the Sp1 level in highly invasive lung adenocarcinoma cells resulted from instability of the Sp1 protein. Furthermore, overexpression of Sp1 in highly invasive lung adenocarcinoma cells increased expression of E-cadherin, a suppressor of metastasis, and attenuated the translocation of β-catenin into the cellular nucleus which leads to tumor malignancy. Taken together, Sp1 level accumulated strongly in early stage and then declined in late stage, which is important for lung cancer cell proliferation and metastasis during tumorigenesis.

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-304. doi:1538-7445.AM2012-LB-304
Abstract LB-429: Dormant cancer cells contribute to residual disease in a mouse model for reversible pancreatic cancer
Authors: Lin Wan-Chi , Rajbhandari Nirakar , Liu Chengbao , Sakamoto Kazuhito , Batra Surinder , Opavsky Rene , Felsher Dean , Hollingsworth Michael , Hebrok Matthias , Rui Hallgeir , Wagner Kay-Uwe
Published: August 2012

The initiation and progression of premalignant lesions into pancreatic ductal adenocarcinomas (PDACs) is governed by a series of genetic changes, but it is still unknown whether these alterations are still required for the maintenance of primary and metastatic PDAC. Here we show that the c-Myc oncogene is upregulated throughout the entire process of neoplastic progression in human PDAC. To address whether this oncogene is essential for the growth and survival of cancer cells, we developed a novel mouse model that allows a temporally and spatially controlled expression of c-Myc in pancreatic progenitors and derived lineages of the exocrine pancreas. Upregulation of c-Myc is sufficient to cause adenocarcinomas after a short latency, and haploinsufficiency in Cdkn2a dramatically increases the rate of metastasis. Despite a macroscopically complete regression of primary, metastatic, and transplantable tumors following the downregulation of c-Myc, some cancer cells remain dormant. A significant number of these residual neoplastic cells express cancer stem cell markers, and re-expression of exogenous c-Myc leads to rapid cancer recurrence. Collectively, the results of this study suggest that c-Myc plays a significant role in the progression and maintenance of PDAC, but additional therapeutic strategies are necessary to eradicate residual cancer cells to prevent cancer relapse.

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-429. doi:1538-7445.AM2012-LB-429
Abstract LB-431: Augmented induction of tumor antigen-specific CTL by cetuximab in head and neck cancer patients does not correlate with Fcγ receptor IIIa genotype, but relies on NK:DC cross talk mediated by interferon-γ and NKG2D
Authors: Lord Christopher A. , Srivastava Raghvendra M. , Lee Steve C. , Filho Pedro A. Andrade , Gibson Sandra P. , Gooding William E. , Ferrone Soldano , Ferris Robert L.
Published: August 2012

Despite over-expression of epidermal growth factor receptor (EGFR) in 80-90% of head and neck cancers (HNC), only ∼20% of HNC patients are clinically responsive to treatment with the EGFR-specific monoclonal antibody (mAb) cetuximab. To date, no reliable biomarker of clinical efficacy has been identified to predict clinical response to cetuximab therapy in HNC. Modest, yet statistically significant correlations of Fcγ receptor (FcγR) IIIa polymorphisms with clinical outcome have been noted in B cell lymphoma, breast, and colorectal cancer patients treated with rituximab, trastuzumab, and cetuximab, respectively. Therefore, we have investigated whether a known FcγRIIIa polymorphism in natural killer (NK) cells at amino acid position 158 (valine [V] vs. phenylalanine [F]) correlates with the anti-tumor activity of cetuximab in immunodeficient mice engrafted with human HNC tumors as well as with the induction of EGFR-specific cytotoxic T lymphocytes (CTL) and clinical course in HNC patients treated with cetuximab. When injected into immunodeficient mice, human NK cells expressing the V allele at this position demonstrated significantly greater ability to control the growth of xenografted HNC tumors. However, we did not find a significant correlation between FcγRIIIa genotype and disease free survival (p=0.683) in a cohort of 107 consecutive HNC patients treated with regimens incorporating cetuximab. Furthermore, we demonstrate for the first time that in the presence of cetuximab-opsonized HNC cells, NK cells trigger maturation of dendritic cells (DC), leading to augmented TA-specific cross-priming of EGFR and MAGE-specific CTL in vitro, and in vivo in cetuximab-treated HNC patients. The significantly higher frequencies of EGFR-specific CTL we found in HLA-A2+ PBMC from cetuximab-treated HNC patients relative to cetuximab-naive HNC patients (p<0.001) also did not correlate with FcγRIIIa genotype, but their induction was dependent on NK:DC cross talk mediated by interferon-γ and NKG2D. Taken together, our data indicate that cetuximab treatment augments the priming of both EGFR and non-EGFR TA-specific cellular immunity in vivo, thereby providing a novel immune mechanism for enhanced anti-tumor activity of TA-specific mAb relevant to clinical response, as well as a potential biomarker for monitoring this response in mAb-treated 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 LB-431. doi:1538-7445.AM2012-LB-431
Abstract LB-434: Baseline serum adrenal androgens are prognostic and predictive of overall survival (OS) in patients (pts) with metastatic castrate-resistant prostate cancer (mCRPC): Results of the COU-AA-301 phase 3 randomized trial
Authors: Ryan Charles , Li Jinhui , Kheoh Thian , Scher Howard I. , Molina Arturo
Published: August 2012

Objective In COU-AA-301 the androgen biosynthesis inhibitor abiraterone acetate (AA) significantly increased OS vs placebo (PL) in mCRPC post-docetaxel (HR=0.74; Scher, ASCO 2011). The objective of the current study was to determine the effect of baseline levels of adrenal androgens (testosterone [T], androstenedione [A4], and dehydroepiandrostenedione [DHEA]) on OS in COU-AA-301. Methods COU-AA-301 is a randomized double blind study of AA (1000 mg QD + prednisone [P] 5 mg po BID) vs PL + P. In this post hoc exploratory analysis, the effect of baseline serum androgen levels (T, A4, DHEA) on OS was determined by univariate and multivariate analyses using the Cox proportional hazards regression model. Cut offs for high hormone (HH; above median) and low hormone (LL; below median) levels were used. Pts were stratified by ECOG PS (0-1 vs 2), pain (pain 4-10 [present] vs pain 0-3 [absent]), 1 vs 2 prior chemotherapy regimens, and type of progression (PSA only vs radiographic). Results Higher baseline serum androgens (T, A4, and DHEA) were associated with significantly improved OS, in either univariate or multivariate analysis, adjusting for treatment, other androgens, and other lab parameters (ie, LDH, HGB, ALKP, PSA; all p<0.0001). OS was significantly longer in HH group vs LH group in both AA + P and PL + P arms for T, A4, and DHEA (Table); the longer OS observed with AA + P vs PL + P was observed in both HH and LH groups for T, A4, and DHEA. Conclusions In study COU-AA-301, baseline adrenal androgens were both prognostic and predictive of OS in patients with mCRPC. Pts treated with P alone had longer OS in the HH group vs LH group, suggesting P modulation of the adrenal axis. AA was beneficial in both HH and LH groups, but the effect appeared more pronounced in the HH group. Additional work is underway to further understand the relationship between serum and intratumoral androgens and outcomes.

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-434. doi:1538-7445.AM2012-LB-434