bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A28: The link between the metabolic effects of nuclear receptor (NR) modulators and anticarcinogenic properties on leukemia cancer cells can be revealed through studying the Warburg effect
Authors: Attia Ramy R. , Min Jaeki , Guy R. Kiplin
Published: June 2012

The Warburg effect is the observation that most cancer cells predominantly produce energy by a high rate of glycolysis followed by lactic acid fermentation in the cytosol, rather than by a comparatively low rate of glycolysis followed by aerobic oxidation of pyruvate in mitochondria. Genetic studies in humans and rodents support the notion that metabolic enzymes controlling glucose metabolism can directly contribute to carcinogenesis. Current knowledge of nuclear receptor (NR) signaling networks indicates that NRs control a wide variety of metabolic processes by regulating the expression of genes encoding key enzymes, transporters, and other proteins involved in metabolic homeostasis. Thus, a better understanding of the mechanistic links between cellular metabolism control by NRs and cancer cells' growth control may ultimately lead to better treatments for human cancer. We created a library of 134 NR modulators including compounds targeting the estrogen receptor (ER), androgen receptor (AR), farnesoid X receptor (FXR), peroxisome proliferator-activated receptor (PPAR), retinoic acid receptor (RAR), retinoid X receptor (RXR), glucocorticoid receptor (GR), mineralocorticoid receptor (MR), liver X receptor (LXR), thyroid receptor (TR), and pregnane X receptor (PXR). We used high-throughput assays to measure cell viability, apoptosis, and cell proliferation of leukemic cell lines after treatment with this library. Afterwards, compounds which highly induced apoptosis and inhibited cell proliferation were picked for further investigation of their mechanism of action. We linked the effect of those compounds on apoptosis to their effect on lactate levels. In addition, we tested the effect of these compounds on the activity of pyruvate dehydrogenase complex (PDC) which catalyzes the irreversible oxidative decarboxylation of pyruvate into acetyl-CoA an important step in commitment of glucose into full oxidation rather than glycolysis, PDH dipstick assay was used for this purpose. Of the 134 nuclear receptors modulators that we have tested, nine compounds induced significant apoptosis in Jurkat cells. These compounds mainly targeted ER and RAR. On the other hand, only six compounds from this list significantly reduced the lactate levels in Jurkat cells. Finally, the compounds modulating the RAR pathway were the only compounds that showed significant effects on PDC activity. This work may open a door to further explore the RAR modulators as strong potential anticarcinogenic agents.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr A28.
Abstract A45: The tumor suppressor role of ARID1A in gynecologic cancer
Authors: Guan Bin , Wang Tian-Li , Shih le-Ming
Published: June 2012

ARID1A (BAF250A), a gene participating in the formation of a BRG1 SWI/SNF chromatin remodeling complex, has emerged as a potential tumor suppressor because of its frequent inactivating mutations in gynecological cancer (approximately 50% of ovarian clear cell and 30% of ovarian endometrioid carcinomas). The mutation is associated with loss of protein expression as assessed by immunohistochemistry. In this study, we analyzed ARID1A expression in a wide variety of carcinomas to determine the prevalence of ARID1A inactivation in carcinomas using immunohistochemical staining. Immunoreactivity was not detected in 36 (3.6%) of 995 tumors. Uterine low-grade endometrioid carcinomas showed a relatively high-frequency loss of ARID1A expression, as 15 (26%) of 58 cases were negative. Mutational analysis showed 10 (40%) of 25 uterine endometrioid carcinomas; none of 12 uterine serous carcinomas and none of 56 ovarian serous and mucinous carcinomas harbored somatic ARID1A mutations. These findings suggest that the molecular pathogenesis of low-grade uterine endometrioid carcinoma is similar to that of ovarian low-grade endometrioid and clear cell carcinoma, tumors that have previously been shown to have a high-frequency loss of expression and mutation of ARID1A. We further studied the functions of ARID1A and found that restoration of wild-type ARID1A expression in ovarian cancer cells harboring ARID1A mutations suppressed cellular proliferation and tumor growth in mice. Gene silencing of ARID1A in non-transformed epithelial cells enhanced cellular proliferation and tumorigenecity. Mutations in ARID1A and TP53 were mutually exclusive in tumor specimens, and knockdown of ARID1A affected multiple p53-regulated genes and pathways, including CDKN1A and SMAD3. The ARID1A/BRG1 complex bound to the promoters and enhanced transcriptional activity of CDKN1A and SMAD3 in a p53-dependent manner. We further showed that p21 mediated, at least in part, the tumor suppressive functions of ARID1A. These results provide new evidences that ARID1A functions as tissue-type-restricted tumor suppressor by directly modulating transcriptional activity of several p53-regulated genes.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr A45.
Abstract B13: Implication of RNA-binding protein La in proliferation, migration, and invasion of oropharyngeal squamous cell carcinoma cells
Authors: Sommer Gunhild , Rossa Carlos , Chi Angela C. , Neville Brad W. , Heise Tilman
Published: June 2012

The 5-year survival rate for oral cavity cancer is poorer than for breast, colon, or prostate cancer, and has improved only slightly in the last three decades. Hence, new therapeutic strategies are urgently needed. Here, we demonstrate by tissue microarray (TMA) analysis for the first time that RNA-binding protein La is significantly overexpressed in oral squamous cell carcinoma (SCC). We therefore addressed the question whether siRNA-mediated depletion of the La protein may interfere with known tumor-promoting characteristics of head and neck SCC cells. Our studies demonstrate that the La protein promotes cell proliferation, migration, and invasion of lymph node-metastasized hypopharyngeal SCC cells. We also reveal that La is required for the expression of β-catenin as well as matrix metalloproteinase type 2 (MMP-2) within these cells. Taken together, these data suggest a so far unknown function of the RNA-binding protein La in promoting tumor progression of head and neck SCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr B13.
Abstract B2: Effect of a changing microenvironment on the role of ROR receptors in melanoma progression
Authors: O'Connell Michael P. , Camilli Tura , Weeraratna Ashani T.
Published: June 2012

We have previously demonstrated that increases in Wnt5A result in an increase in metastatic capacity of melanoma cells and a decrease in the melanoma differentiation antigens MART1 and gp100. These data have been supported by several other laboratories, giving rise to the phenotype switching model of melanoma progression. This model suggest that less aggressive melanomas express a proliferative gene expression signature governed by the transcription factor MITF, while more aggressive melanomas express an invasive gene expression signature, governed by Wnt5A (Hoek et al, 2010). We hypothesize that this phenotype switch can be influenced by the changing microenvironment and that ROR receptor expression, also influenced by the microenvironment, is a key metastatic biomarker in melanoma.

The orphan tyrosine kinase receptors, ROR1 and ROR2, make up a superfamily of receptors that, until recently, had no known signal pathway association or ligand identification. ROR2 has since been shown to play a role in Wnt signal transduction and studies from our laboratory have demonstrated an important role for ROR2 in increasing the metastatic potential of melanoma cells. Very little remains know about ROR1 in melanoma. Here, we demonstrate that ROR1 expression is inversely correlated to that of ROR2 and decreasing ROR1 expression increases overall metastatic potential. In keeping with these data, reduction of ROR1 by siRNA demonstrates a decrease in MART1 and GP100, and motility, and an increase in the invasive capability of melanoma cells. In addition, siRNA knockdown of ROR1 expression increased ROR2, Wnt5A, and clathrin expression, and treatment with recombinant WNT5A decreased ROR1 expression, implying that downregulation of ROR1 may be an important event in increasing malignancy in melanoma. Further, ROR2 knockdown in cells that have high levels of Wnt5A, but low levels of ROR1, increases ROR1 expression. Based on this data, ROR1/ROR2 receptor expression appears to be involved in melanoma cell phenotype switching. As ROR2 has previously been shown to be induced by HIF1-α, we asked if this ROR phenotype switch was controlled, in part, by hypoxia. Our data suggests that cells can increase their ROR2 levels by exposure to hypoxia. This is concomitant with a decrease in proliferation and an increase in invasion and Wnt5A expression.

Overall these data suggest that changes in the melanoma microenvironment, such as hypoxia, may result in a switch from ROR1 positivity to ROR2 positivity, which ultimately contributes to increases in metastatic potential.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr B2.
Abstract B20: GLI1 overexpression contributes to HCC recurrence partly through the induction of SNAI1-induced epithelial-to-mesenchymal transition
Authors: Zheng Xin , Gai Xiaohong , Fernandez-Zapico Martin , Roberts Lewis , Moser Catherine , Hu Chunling , Nakamura Ikuo , Shire Abdirashid , Yang Judong , Elsawa Sherine , Almada Luciana , Thorgeirsson Snorri
Published: June 2012

Background/Aim: Glioma-associated oncogene 1 (GLI1) is one of the most important transcription factors in the hedgehog (Hh) signaling pathway and has been shown to be involved in embryonic development and tumor progression. The epithelial-to-mesenchymal transition (EMT) is an important cellular program which contributes to invasion and metastasis of cancer. We have previously shown that GLI1 may promote HCC metastasis via EMT. Here, we demonstrate that GLI1 upregulates SNAI1 expression, induces EMT, and promotes HCC recurrence in vivo and in vitro.

Methods: Gli1 mRNA was assessed in 139 HCCs by microarray and its correlation with HCC recurrence and SNAI1 mRNA expression was analyzed. In vitro, the mRNA and protein expression of GLI1 was measured in Gli1-negative Huh7 cells transfected with GU1 and GU1-expressing SNU398 cells transfected with antisense oligonucleotides targeting GU1 (GLI1 ASO). GLI1-dependent transcriptional activity was assessed with GU reporter luciferase assay and electrophoretic mobility shift assay (EMSA). The interaction between Gli1, SNAI1 and EMT was assessed by real-time PCR, Western immunoblotting and immunofluorescence. Effects of GLI1 on proliferation, viability, migration, and invasion of tumor cells were also assessed.

Results: GLI1 mRNA was detected in 74 HCC tumors and found to be upregulated in 43 (58.1 %) HCCs. Increased Gli1 mRNA in HCCs was associated with tumor recurrence after resection. There was a positive correlation between GLI1 and SNAI1 mRNA expression. In HCC cells, GLI1 overexpression increased Gli1-dependent transcriptional activity, proliferation, viability, migration, and invasion of tumor cells. GU1 also increased SNAI1 expression and induced the EMT. Opposite effects were observed in GU1-knockdown models.

Conclusion: Together, these findings identify a novel mechanism mediating HCC recurrence that includes GLI1-mediated activation of EMT via upregulation of SNAI1.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr B20.
Abstract B3: Induction of Smad4 in response to serum starvation promotes cell death through PUMA stabilization
Authors: Lee Sun-Hye , Jung Youn-Sang , Chung Ji-Yun , Oh Ah-Young , Lee Su-Jin , Park Bum-Joon
Published: June 2012

Smad4 is an essential factor in TGF-β signaling and is also known as frequently mutated tumor suppressor gene in human pancreatic and colon cancer. However, considering the fact that TGF-β can contribute to cancer progression through transcriptional target genes such as Snail, MMPs, and EMT-related genes, loss of Smad4 in human cancer would be required for obtaining the TGF-β signaling independent advantage, which should be essential for cancer cell survival. Here we provide the evidence about novel role of Smad4, serum-deprivation-induced apoptosis. Elimination of serum can obviously increase the Smad4 expression and induces the cell death by p53-independent PUMA induction. Instead, Smad4 deficient cells show the resistance to serum starvation. Induced Smad4 suppresses the PAK1, which promotes the PUMA destabilization. We also found that siah-1 and pVHL are involved in PAK1 destabilization and PUMA stabilization. In fact, Smad4-expressed cancer tissues show the elevated expression of PAK1, also supprots our hypothesis that Smad4 induces PUMA-mediated cell death through PAK1 suppression. Our results strongly suggest that loss of Smad4 render the resistance to serum-deprivation-induced cell death, which is the TGF-β independent tumor suppressive role of Smad4.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr B3.
Abstract B33: Transcriptional control of genome surveillance and repair by a metabolic switch
Authors: Di Li-Jun , Wong Madeline M. , Wakano Clay T. , Byun Jung , Varticovski Lyuba , Hunter Kent , Olopade Olufunmilayo I. , Gardner Kevin
Published: June 2012

A hallmark of primitive and more aggressive breast cancer is increased genome instability due to deficits in DNA repair. Recently we described a molecular mechanism through which the NADH regulated protein C-terminal binding protein (CtBP) represses the expression of the Breast Cancer One tumor suppressor gene BRCA1. These initial observations provided a molecular mechanism through which specific aspects of genome repair and stability, mediated by BRCA1, could be controlled by cellular metabolic status. By profiling the global interactions of CtBP with the breast cancer genome via chromatin immuno-precipitation combined with deep sequencing (ChlP-seq), we now reveal that CtBP acts both as a co-transcriptional repressor and activator to integrate distinct pathways that control genome stability, epithelial to mesenchymal transition, and stem cell transcriptional programming. Breast cancer cells depleted of CtBP show increased DNA repair as detected by comet and gamma H2AX foci formation assays. Over-expression of CtBP shows loss of the CD24 luminal surface marker while CtBP depletion increases CD24 expression. Kaplan-Meier survival analysis, based on our CtBP targeted gene lists, distinguishes breast cancer patients with worst outcome/survival in several published gene expression studies. Finally, tissue micro-array studies reveal significantly higher staining of CtBP predominantly in patients with poorly differentiated, triple negative and basal-like morphologic and molecular phenotypes. We propose a model in which CtBP acts at multiple levels to enhance dedifferentiation and genomic instability in malignancies of the breast.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr B33.
Abstract B37: A DNA polymerase beta gene harboring the colon cancer-associated G231D variant increases the sensitivity of cells to chemotherapeutic agents and induces cellular transformation
Authors: Nemec Antonia A. , Donigan Katherine A. , Murphy Drew L. , Jaeger Joachim , Sweasy Joann B.
Published: June 2012

Rapidly advancing technology has resulted in the generation of the genomic sequences of several human tumors. These studies have revealed that tumors are heterogeneous and contain many mutations, supporting the mutator phenotype hypothesis of human cancer. Drivers of carcinogenesis are thought to be mutated genes that occur at high frequencies in large numbers of human tumors. However, functional characterization of many of the somatic mutations is lacking. We have identified several mutations of the DNA polymerase beta (POLB) gene in human colorectal cancer. Pol beta is the main polymerase involved in the base excision repair (BER) pathway and aberrant expression of Pol beta has been linked to a cancerous phenotype. In this study, we characterized the homozygous G231D mutation that was identified in a Stage 3 colorectal tumor. We have demonstrated that its expression in epithelial cells induced cellular transformation and increased the rate of proliferation. The transformed phenotype persisted in the cells even once the expression of G231D was extinguished. These data indicated that the expression of G231D caused an inheritable change; this change is most likely due to an increase in genomic instability caused by unfilled gaps proceeding through replication. Expression of G231D was insufficient to rescue Pol beta-deficient cells treated with chemotherapeutic agents suggesting that these agents may be effectively used to treat tumors harboring this mutation. Biochemical analysis of G231D revealed that it was 100-fold slower than WT Pol beta as determined by pre-steady state kinetics. The slow rate was a result of the decreased binding affinity of nucleotides by G231D. Residue 231 of Pol beta lies in close proximity to the template strand of the DNA. Molecular modeling showed that the change from a glycine to a negatively charged amino acid caused a repulsion between the template and residue 231 leading to the disruption of the dNTP binding pocket. Together, these data indicate that a person harboring the G231D Pol beta mutation may have an increased risk of cancer. Moreover, the altered sensitivity to chemotherapeutic drugs in cells carrying the G231D variant may have further implications in how to better improve the therapeutic outcome in patients with this mutation and supports the need for personalized cancer therapies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr B37.
Abstract B48: Aurora kinase A plays a central role in the differentiation, survival, and self-renewal of human neuroblastoma SK-N-BE(2)-derived cancer stem cells
Authors: Sparta Antonino Maria , Potrich Valentina , Quattrone Alessandro , Provenzani Alessandro
Published: June 2012

Aurora kinase A is upregulated in numerous types of cancers. Since this protein is involved in mitotic spindle formation and cell cycle progression, its dysregulation leads to aberrant chromosomal segregation and consequent aneuploidy. It has been clarified that Aurora A is a key player in neuroblastoma because of its ability to protect the oncogene product N-myc from degradation, and the over-expression of the two of them represents a negative prognostic factor. Neuroblastoma usually develops in children and, up to the present time, the available pharmacological therapies have proven inadequate to treat the MYCN amplified sub-type of cancer, which is the most aggressive and malignant form of the tumor. Therefore, there is an urgency to develop new strategies that will improve its treatment. A novel approach to contrast cancer development and relapse is to target the subpopulation of the tumor initiating cells (or cancer stem cells), due to their multi-drug resistance and self-renewal abilities.

In this study, we have employed the SK-N-BE(2) cell line as an in vitro human neuroblastoma model, and compared the effects of Aurora A inhibition on the whole population (WP) and on the derived neurospheres (NS) obtained by their continuous growth in selective medium. We tested the effects of both a specific Aurora A inhibitor, ENMD-2076, and a pan-Aurora isoforms blocker, VX-680, for their influence over cellular physiology, morphology and signaling. The specificity of the results was confirmed by the use of a validated Aurora A siRNA.

In SK-N-BE(2) WP and NS, our findings confirmed the ability of Aurora A to protect N-myc from degradation. Moreover, the isolation and characterization by FACS, confocal microscopy and immunoblotting of an aldehyde dehydrogenase-positive side population, confirmed the presence of a fraction of cells with self-renewal capabilities and stem-like properties. The analysis of the signaling network of Aurora A showed functional relationships with the transcription factor STAT3, which is associated with neuronal survival and differentiation, after IL-6 challenge. Furthermore, either Aurora A pharmacological block or silencing induced the phosphorylation of the microtubule associated protein 2 (map2) specifically in the NS, an event that maintains the microtubule in a dynamic state, which is a prerequisite for neurite outgrowth.

Our results suggest that Aurora A represents an amenable target for the treatment of neuroblastoma, and gives new insights into its role in regulating neuronal plasticity and differentiation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr B48.
Abstract B54: The ability of NK cells to perform missing-self rejection of target cells is quantitatively different between individuals and controlled by MHC class I through a process of education
Authors: Brodin Petter , Kärre Klas , Höglund Petter
Published: June 2012

NK cells have the capacity to efficiently kill tumor cells. NK cells will be triggered to do so upon loss of MHC class I expression on the tumor cells, that is missing-self recognition. However, not all NK cells in an individual are able to perform such missing-self responses. The ability to perform missing-self is acquired through a process of education where only NK cells with an ability to interact with MHC class I are allowed full functionality.

We have recently shown that this NK cell education is not a binary but a quantitative process, yielding NK cells that are more or less efficient killers depending on the strength of interaction with self MHC class I during education (Brodin et al Blood 2009).

Here we describe our latest unpublished results on the MHC class I medicated influence on the NK cell system in the mouse. We show that MHC class I not only controls function but also NK cell population dynamics leading to a repertoire of NK cells that differ between individuals in a MHC class I dependent way. Combined these MHC class I mediated effects control the ability of an individual to perform missing-self responses cells lacking MHC class I in vivo.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr B54.
Abstract C27: Phosphorylation of the polycomb group protein polyhomeotic (Ph) induces a relaxed chromatin state through depolymerization of the Ph SAM domain
Authors: Nanves David R. , Leal Belinda , Robinson Angela , Di Lijun , Hakala Kevin , Weintraub Susan , Kim Chongwoo A.
Published: June 2012

The transcriptional repressor polyhomeotic (Ph) is part of the polycomb group (PcG). PcG proteins are responsible for repressing Hox genes, a set of transcription factors that determine segmental identification early in development. PcG proteins are highly conserved throughout evolution, and recent studies have identified that the human homologue polyhomeotic-like protein 3 (PHC3) plays a role in tumor suppression in osteosarcomas. In order to understand how PHC3 functions, we utilized a cellular system with Ph. In our study we found that Ph is phosphorylated at a Ser residue several positions before the SAM domain. This region is important for controlling Ph SAM polymerization raising the possibility that phosphorylation alters the polymeric state of Ph. Phosphorylation was detected only in wild-type Ph and a mutant intended to increase polymerization, but not on polymer deficient Ph mutants. Because Ph repressive ability is dependent on SAM polymerization, we hypothesize that phosphorylation could trigger SAM depolymerization and consequently induce a relaxed chromatin state. To this point, mutating the phosphorylated Ser to Ala produced a better transcriptional repressor than wild-type. These results point to a potential way of controlling Ph SAM polymerization where phosphorylation leads to depolymerization and a replication competent chromatin state. Upon completing replication, the original repressive epigenetic state could be inherited by the daughter cell through dephosphorylation and Ph repolymerization.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr C27.
Abstract C34: The role of COX-2/PGE2 in gossypol-induced apoptosis of colorectal carcinoma cells
Authors: Chen Yen-Chou , Ko Ching Huai , Shen Shing Chuan , Yang Liang Yo
Published: June 2012

Our previous study has shown that gossypol (GOS) exhibited the potent cytotoxic effect via apoptosis induction against human colorectal carcinoma cells; however, the role of cyclooxygenase 2 (COX-2)/prostaglandin E2 on GOS-induced apoptosis is still unknown. In the present study, 12-O-tetradecanoylphorbol-13-acetate (TPA) addition significantly inhibited GOS-induced apoptosis in human colorectal carcinoma cells COLO205 in according with inducing COX-2 protein/PGE2 production. TPA inhibition of GOS-induced apoptosis was blocked by adding protein kinase C (PKC) inhibitors including ST, GF, and H7, characterized by an occurrence of cleaved caspase 3 proteins and a decrease in COX-2 protein/PGE2 production in COLO205 cells. Addition of COX activity inhibitors including NS398, aspirin (AS), diclofenac (DI), and indomethacin (IN) suppressed TPA protection of GOS-induced apoptosis with decreased PGE2 production in COLO205 cells. Application of PGE2, but not it analogues PGD2, PGJ2, and PGF2, protected COLO205 cells from GOS-induced DNA ladders, and the EP1 receptor agonist 17PT-PGE2 mimicked the protection by PGE2, whereas the selective EP2 receptor agonist butaprostol (BUT), EP3 receptor agonist sulprostol (SUL), and EP4 receptor agonist PGE1 alcohol (PGE1) showed no significant effect on GOS-induced apoptosis in COLO205 cells. PGE2 protection of GOS-induced apoptosis was reversed by adding a selective EP1 receptor antagonist SC-19220. Furthermore, GOS had less apoptotic effect on HT-29 colorectal carcinoma cells which expressed higher level of endogenous COX-2 protein than COLO205 cells, and decreased COX-2 protein level via COX-2 siRNA significantly elevated GOS-induced cell death in HT-29 cells. COLO205-T cells were established through sustained TPA incubation of COLO205 cells, and COLO205-T cells showed a lower sensitivity to GOS-induced cell death with increased COX-2 (not Bcl-2 and Mcl-1) protein than parental COLO-205 cells. A decrease in COX-2 protein expression in COLO205-T cells by COX-2 siRNA transfection enhanced GOS-induced cell death by MTT assay. The notion of COX-2/PGE2 activation against GOS-induced apoptosis in colon carcinoma cells was demonstrated, and combination of GOS and COX-2 inhibitors to treat colon carcinoma reserved clinical potential for further investigation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr C34.
Abstract C36: Dc917 inhibits the growth of mouse lung carcinoma both in vitro and in vivo through cell cycle arrest and ERK signaling pathway
Authors: Dong Hang , Jiang Zhihong , Wong Vincent Kam Wai , Zhou Hua , Liu Liang
Published: June 2012

Background: Chemotherapeutic agents often exhibit adverse effects to patients because of their nonspecific cytotoxic effect, and therefore we have screened anticancer compounds from a natural source. Dc917, a novel derivative from a Chinese medicinal plant, exhibited specific cytotoxic effect to a panel of cancer cells but no marked impairment to human normal lung fibroblasts, and it significantly suppressed tumor growth in xenograft-bearing mice. We thus aimed to further investigate molecular mechanisms of Dc917.

Methods: Cell viability and cell cycle distribution were determined by MTT assay and flow cytometry, respectively. Immunoblotting was performed to determine changes in protein levels. Knockdown of desired protein was achieved by transfection with siRNA. Meanwhile, C57BL/6 mice bearing lung carcinoma cells were used to estimate the antitumor activity in vivo.

Results: Dc917-induced significant cell cycle arrest in S phase was concomitant with downregulations of cdks and cyclins, as well as upregulations of p21 and p27 expression. The complex formation between cdk2/cyclin E and cdk4/cyclin D1 was reduced; however, the recruitment of p21 or p27 to cyclin E/Cdk2 complex was increased by Dc917 incubation. In addition, Dc917-induced cell death and S phase arrest were significantly attenuated by knockdown of p21 or p27 protein. Dc917 also induced MAPK and p53 pathway, which activated p27/p21 and subsequently suppressed cyclin/cdk complexes activity, and the inhibitor of ERK (U0126) could suppress Dc917-induced cytotoxicity and upregulation of p53/p27 or p21 and egr-1/p27 or/p21 expression.

Conclusions: Our preclinical data indicated that Dc917 is a potential therapeutic agent in vitro and in vivo, and further development of this agent for cancer therapy is processing.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr C36.
Abstract C40: Recombinant viral protein suppresses metastasis of ovarian adenocarcinoma cells through negative Akt signaling
Authors: Peng Jei-Ming , Hung Shao-Wen , Chiu Ching-Feng , Ho Ming-Yi , Hsiao Michael , Liang Chi-Ming , Liang Shu-Mei
Published: June 2012

Ovarian cancer has a high fatality rate, mainly due to metastatic progression of tumor cells. Advances in the treatment of metastatic ovarian cancer are needed. Here, we studied the mechanism of action of a recombinant viral capsid protein (rVP1) and explored its effect against ovarian tumor growth and metastasis in vivo. We found that rVP1 was cytotoxic to several human ovarian cancer cell lines, namely doxorubicin-resistant SKOV3, cisplatin-resistant OVCAR-3, and TOV-21G. rVP1 was more potent than doxorubicin and cisplatin in inducing apoptosis and inhibiting growth of SKOV3 in vitro. Treatment of SKOV3 or peritoneal adapted SKOV3ip.1 cells with rVP1 at certain concentrations below IC50 resulted mainly in inhibition of cell invasion rather than apoptosis. This inhibitory effect of rVP1 on cell invasion was accompanied with activation of PTEN and GSK-3β as well as downregulation of FAK, Akt and MMP-2. Anti-integrin antibodies or overexpression of constitutively active Akt reversed the cellular effects of rVP1. In vivo studies confirmed that rVP1 attenuated survival and metastasis of SKOV3 cells through the selective regulation of Akt and GSK-3β activity in an orthotopic xenograft mouse model as revealed by bioluminescence imaging of mice and immunohistological analysis. In addition, rVP1 decreased the formation of ascites and metastatic tumor nodules formed by SKOV3 cells in an intraperitoneal xenograft mouse model. These results indicate that negative regulation of Akt signaling by rVP1 may have the potential to suppress ovarian tumor growth and metastasis in vivo.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr C40.
Abstract C42: Survival signals differentially turn on during TRAIL or curcumin/TRAIL treatment
Authors: Oh Seeun , Kim Joo-Hang , Song Jae J. , Kim Jina , Yoon Hyo R. , Kang Sujin , Park Wungki , Hong Kijae , Kim So Y. , Choi Hye J.
Published: June 2012

Previously, we have shown that p38-HSP27 acted as modulators from survival to death depending on the apoptotic strength in prostate cancer cells. For example, if the apoptotic strength is in the moderate range, p38-HSP27 acted to increase Akt catalytic activity, whereas if in the stronger range, p38-HSP27 acted to decrease Akt catalytic activity as well as Akt dephosphorylation. Moreover, another survival signal, Src, a non-receptor tyrosine kinase was revealed to be highly phosphorylated (activated) during curcumin/TRAIL treatment, which leads to the conclusion of occurrence of more complex regulatory crosstalk between Akt and Src for the strict control of cell homeostasis. As a consequence, Akt dephosphorylation was regulated by protein phosphatase 1 (PP1), whose activity was subsequently controlled by dissociation from HSP27 (increase) and Src phosphorylation (deccrease). Src phosphorylation during curcumin/TRAIL was also positively regulated by TRAF6, whereas it was negatively regulated by HSP27. Taken together, the level of Akt dephosphorylation during curcumin/TRAIL could be decided by cumulative factors such as the levels of HSP27/TRAF6 and the activity of Src and PP1.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr C42.
Abstract C50: Dysregulation of microRNA-34a expression causes drug resistance to 5-FU in human colon cancer DLD-1 cells
Authors: Akao Yukihiro
Published: June 2012

MiR-34a was identified as one of the downregulated microRNAs (miRs) in human colorectal cancer 5-fluorouracil (5-FU)-resistant DLD-1 cells compared with those in the parental DLD-1 cells. Exposure to 5-FU at 30 μM activated phosphoinositide 3-kinase (PI3K)/Akt signaling markedly from 12 h up to 48 h in the 5-FU-resistant cells compared with that in the parental cells and resulted in an overt difference in growth at those times. Furthermore, the expression of miR-34a in the 5-FU-resistant cells was sustained at a low level, whereas it was upregulated in the parental cells after the 5-FU treatment. Sirt1, which is one of the target genes for miR-34a and related to drug resistance, was strikingly upregulated in the 5-FU-resistant cells. The ectopic expression of miR-34a in the 5-FU-resistant cells inhibited growth, as in the parental cells, and attenuated the resistance to 5-FU through the downregulation of Sirt1 and E2F3. Moreover, the silencing of Sirt1 significantly canceled the resistance to 5-FU in the 5-FU-resistant cells. These findings suggest that miR-34a targeting the Sirt1 and E2F3 genes could negatively regulate, at least in part, the resistance to 5-FU in human colorectal cancer DLD-1 cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr C50.
Abstract C52: Collagen-mediated chromatin remodeling promotes chemoresistance in pancreatic cancer
Authors: Danqi-Garimella Surabhi Y. , Munshi Hidayatullah G.
Published: June 2012

Pancreatic ductal adenocarcinoma (PDAC), the fourth leading cause of cancer-related deaths in the U.S., is associated with a pronounced collagenrich stromal reaction that has been shown to contribute to chemoresistance. We recently published that PDAC cells grown in the collagen microenvironment are resistant to gemcitabine-induced proliferation and checkpoint arrest (Dangi-Garimella et al, Cancer Research 2011). The effects were mediated through upregulation of membrane type 1-matrix metalloproteinase (MT1-MMP)- and ERK1/2-dependent expression of high mobility group A2 (HMGA2), a well-known chromatin remodeling protein. We have now found that relative to cells grown on tissue culture plastic, PDAC cells grown in 3-D collagen display increased acetylation of lysines K9 and K27 on histone H3 along with a reduction in the levels of the heterochromatin binding protein HP1-α, suggesting that cells in collagen have a more open chromatin state. Decreasing MT1-MMP or HMGA2 expression or inhibiting ERK1/2 activity attenuates the effect of collagen on K9 and K27 acetylation. Collagen also increases Aurora kinase B-dependent phosphorylation of S10 on histone H3, which has been shown to reduce HP1-α binding to the chromatin and thereby promote more open chromatin state. 3-D collagen also increases expression of the histone acetyl transferase enzymes pCAF and GCN5. Finally, cells in 3D matrix demonstrate increased H2AX and a reduced tailing with the comet assay following gemcitabine treatment, suggesting that there is increased DNA repair associated with the more open chromatin state when cells are in the 3-D collagen microenvironment. Overall, our results increase our understanding of how growth in 3-D collagen contributes to chemoresistance and identify potential therapeutic targets against this deadly cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr C52.
Abstract C64: Iron regulatory gene signature predicts outcome in breast cancer
Authors: Miller Lance D. , Coffman Lan G. , Chou Jeff W. , Black Michael A. , Bergh Jonas , D'Agostino Ralph , Torti Suzy V. , Torti Frank M.
Published: June 2012

Extensive experimental and clinical literature attests to the importance of iron in tumor cell growth. For example, high levels of dietary iron have been linked epidemiologically to the increased development of tumors in humans; in animal models, levels of dietary iron affect tumor growth. However, pathways that underlie the apparent demand for iron by tumors remain largely uncharacterized. We recently discovered that an iron efflux pathway plays a role in breast cancer growth and metastasis: expression of the iron efflux pump ferroportin and its regulator hepcidin were predictive of metastasis-free survival in multiple independent breast cancer cohorts. To determine the optimal “iron gene regulatory signature,” we used microarray datasets comprising 674 breast cancer cases to systematically investigate how expression of genes related to iron metabolism is linked to breast cancer prognosis. Of 61 genes involved in iron regulation, 49% were statistically significantly associated with distant metastasis-free survival (DMFS). Optimal risk stratification was achieved with a model comprising 16 genes, which we term the iron regulatory gene signature (IRGS). Multivariable analysis revealed that the IRGS contributes information not captured by conventional prognostic indicators (hazard ratio 1.61; 95% CI 1.16–2.24; p=0.004). The IRGS successfully stratified homogeneously treated patients, including ER+ patients treated with tamoxifen monotherapy, both with (p=0.006) and without (p=0.03) lymph node metastases. To test whether multiple pathways were embedded within the IRGS, we evaluated the performance of two gene dyads with known roles in iron biology in ER+ patients treated with tamoxifen monotherapy (n=371). For both dyads, gene combinations that minimized intracellular iron content (anti-import: TFRCLow/HFEHigh; or pro-export: FPHigh/HAMPLow) were associated with favorable prognosis (p<0.005). Although the clinical utility of the IRGS will require prospective evaluation, its ability to both identify high risk patients within traditionally low risk groups and low risk patients within high risk groups has the potential to affect therapeutic decision-making.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr C64.
Abstract C67: Gene expression profiling with human breast cancer cell lines exposed to gephyronic acid
Authors: Young Jeanette , Leliaert Amy , Schafer Zachary T. , Taylor Richard E.
Published: June 2012

Gephyronic acid is an antibiotic natural product isolated at the HZI (Helmholtz-Zentrum für Infektionsforschung) by Sasse and Höfle from the myxobacterium Archangium gephyra in 1995. Gephyronic acid has been shown to inhibit the growth of yeast and mold in the micromolar range; it also exhibits a cytostatic effect on mammalian cell cultures (human cervix, human leukemia, hamster kidney, hamster ovary, mouse connective tissue, and monkey kidney cancer cells) in the nanomolar range. An in vitro translation assay demonstrated that gephyronic acid is a specific inhibitor of eukaryotic protein synthesis. Interdisciplinary efforts within our laboratory are directed to the evaluation of gephyronic acid as a potential anticancer agent and its structural and biological relationship to the myriaporones and tedanolides. Our recent structural assignment and total synthesis of gephyronic acid incorporates a synthetic route that provides a means by which to access significant quantities of gephyronic acid efficiently and selectively, thus facilitating further biological evaluation. Additionally, we seek to identify the mode of action for gephyronic acid by screening various cancer cell lines through transcriptome and proteome profiling. Our proposed method will analyze mRNA expression levels of cells treated with gephyronic acid, or without for control, through the application of cDNA microarrays. Transcript profiling will then be coupled to proteomic profiling utilizing a method of protein labeling called iTRAQ. Identifying specific genes and their associated proteins will secure the mode of action of gephyronic acid selective activity and further defines potential as a chemotherapeutic lead.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr C67.
Abstract IA12: Induction of pluripotency by defined factors
Authors: Yamanaka Shinva
Published: June 2012

Induced pluripotent stem (iPS) cells were originally generated from mouse and human fibroblasts by the retroviral introduction of Oct3/4, Sox2, c-Myc, and Klf4. iPS cells are similar to embryonic stem (ES) cells in morphology, proliferation, gene expression, and most importantly, pluripotency. Patient-specific iPS cells provide us with unprecedented opportunities in disease research, drug screening, toxicology, and cell transplantation therapies. Banks of iPS cells from individuals with HLA homozygous alleles may also provide another unprecedented source for regenerative medicine.

iPS cells have many variations in comparison to ES cells. In addition to fibroblasts, iPS cells can be generated from various somatic cells, such as hepatic cells, gastric epithelial cells, keratinocytes, neural cells, peripheral blood cells, and cord blood cells. In addition to retroviral transduction, iPS cells can be integration-freely generated by adenoviruses, sendaiviruses, plasmids, transposons, recombinant proteins, and synthetic mRNA. Several chemicals and inhibitors have been shown to enhance iPS cell generation. Some of the original four factors can either be omitted or replaced by other genes or chemicals. Finally, each induction experiment can result in 100 or more independent iPS cell clones.

These various iPS cells may vary significantly in regard to each cell's peculiar characteristics, such as the efficacy of in vitro directed differentiation and a propensity to produce tumors. In fact, the origins of iPS cells have a profound effect on their tumorigenicity. It is therefore necessary to determine the best origins, the best induction protocols, and the best methods to evaluate iPS cell clones and subclones for each application of iPS cells. Here, significance of epigenome analyses, including methylome, histone modifications, and imprinting increases as the integration-free method is becoming practical.

It is also important to note that an iPS cell clone can be heterogeneous despite the fact that all the cells within the clone are derived from a single progenitor cell. This is because the process requires multiple cell divisions which cannot be completed by the four exogenous factors alone. Additional factors including p53 and Rb pathways are considered to play various roles in achieving full reprogramming. Obtaining a better understanding of the reprogramming mechanisms will therefore facilitate the generation of more uniform iPS cells in the future.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr IA12.
Abstract IA14: Reprogramming cell fate by mimicking natural mechanisms
Authors: Blau Helen M.
Published: June 2012

We are exploiting natural mechanisms to derive mammalian cell sources for regenerative medicine: (1) by recapitulating pathways used by newts and zebrafish, (2) by mimicking biophysical cues to which adult stem cells are exposed in the body, (3) and by gaining insights into the mechanisms such as DNA demethylation by which adult cells are reprogrammed to pluripotency (iPS) in heterokaryons. These approaches provide fundamental mechanistic insights into stem cell fate determination, provide novel cell sources, and enable clinical applications of cell therapies for regenerative medicine.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr IA14.