bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3980: Hypoxia-induced microRNA-424 targets CUL2 to stabilize HIF-α isoforms and promotes angiogenesis
Authors: Subramanian Indira V. , Ghosh Goutam , Nguyen Julia , Zhang Xiaoxiao , Joshi Hemant P. , Zeng Yan , Ramakrishnan Sundaram
Published: June 2012

Chronic hypoxia, a hallmark of many tumors, is associated with angiogenesis and tumor progression. Adaptive changes to oxygen availability are critical for cell survival and homeostasis. Cells respond to hypoxia by modulating oxygen-sensing transducers that stabilize the transcription factor hypoxia-inducible factor 1α (HIF-1α), which transactivates genes governing angiogenesis and metabolic pathways. Oxygen-dependent changes in HIF-1α levels are regulated by proline hydroxylation and proteasomal degradation. Here we provide evidence for a novel mechanism regulating HIF-1α and HIF-2α levels in endothelial cells during hypoxia. Hypoxia differentially increased microRNA-424 (miR-424) levels in microvascular EC, HUVEC and EC progenitor cells purified from the blood. miR-424 targeted cullin 2 (CUL2), a scaffolding protein critical to the assembly of the ubiquitin ligase system, thereby stabilizing HIF-α isoforms. Hypoxia-induced miR-424 in EC was regulated by PU.1-dependent transactivation. PU.1 expression was in turn controlled by RUNX-1 and C/EBPα. Knocking down either C/EBPα or RUNX-1 or PU.1 attenuated hypoxia-driven expression of miR-424 and nuclear translocation of HIF-1α. Furthermore, miR-424 promoted angiogenesis in vitro and in mice, which was blocked by specific morpholinos. These results suggest that miR-424 plays an important physiological role in angiogenesis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3980. doi:10.1158/1538-7445.AM2011-3980
Abstract 3985: MicroRNA-21 regulates Sox2 expression and tumor self-renewal in PDGF-driven glioma
Authors: Roswall Pernilla , Põlajeva Jelena , Swartling Fredrik J. , Jiang Yiwen , Singh Umashankar , Uhrbom Lene , Westermark Bengt
Published: June 2012

The Platelet-Derived Growth Factor (PDGF) has a known role in the progression of malignant primary brain tumors, glioma, but the mechanisms behind PDGF-driven brain tumor development are still not clarified. MicroRNAs regulate many genes in our genome at a post-transcriptional level. We recently identified microRNA-21 (miR-21) as a target in a retroviral screen for candidate brain tumor initiating genes in mice. To explore a role for miR-21 in brain tumors we used Northern blot and in situ hybridization to show that the expression levels of miR-21 in PDGF-induced mouse brain tumors and primary mouse glioma cell lines were strongly increased as compared to normal mouse brain. In normal fibroblasts, the expression of miR-21 was induced by a number of growth factors, including PDGF-B, suggesting miR-21 is downstream of PDGF signaling. By inhibiting PDGF-B with siRNA in Sox2-expressing mouse glioma initiating cells, we showed that miR-21 expression could be suppressed, followed by a decrease in tumor cell self-renewal. To understand the mechanisms of miR-21 in normal development, we identified miR-21 to be highly expressed during embryonic development and in newborn brain with its expression turned off before postnatal day 7 (P7) in the mouse brain. The expression of miR-21 overlapped with Sox2 expression in embryonic and newborn normal mouse brain, whose expression levels similarly decreased at P7. In situ hybridization of miR-21 and IHC staining of Sox2 showed consistent co-expression in mouse brain tumor specimens. Irreversible depletion of miR-21 by using an LNA-modified siRNA was shown to repress Sox2 in primary mouse brain tumor cells but also in human glioma cell lines. Our data suggest that miR-21 regulates Sox2, maintains the tumor initiating cell population and the progression of PDGF-driven brain tumors which insinuates miR-21 as a promising target for future treatment of glioma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3985. doi:10.1158/1538-7445.AM2011-3985
Abstract 3988: Identification of miR-132 and miR-290-3p as putative tumor and metastasis suppressor microRNAs in breast cancer
Authors: Goldberger Natalie E. , Kim Chang Hee , Walker Renard , Hunter Kent
Published: June 2012

Several microRNAs (miRNAs) have been classified as regulators of breast cancer metastasis [1], yet additional unidentified miRNAs may also exist that regulate metastasis. Most interesting, we propose that germline genetic changes may exist which create a predisposition towards developing breast cancer metastasis through the dysregulation of miRNAs. Thus, to identify novel miRNAs associated with a germline predisposition towards breast cancer metastasis, highly metastatic FVB/N-TgN (MMTV-PyMT) mice were crossed with 25 AKXD RI (AKR/J × DBA/2J) strains to produce F1 progeny displaying primary mammary tumors with varying degrees of pulmonary metastasis. The miRNA expression levels within all mammary tumors were evaluated using a miRNA microarray and correlated with the metastatic index for each strain. The analysis produced 27 candidate miRNAs possessing a significant p-value (p < 0.05). To further validate the microarray findings, the expression levels for the most promising miRNAs were measured in mammary tumors from highly metastatic AKR/J and poorly metastatic DBA/2J strains. Downregulation of miR-132 and miR-290-3p was observed in the AKR/J strain versus the DBA/2J strain, consistent with the negative correlation coefficients produced during microarray analysis. In addition, miR-132 miRNA was downregulated in normal breast tissue from the AKR/J compared to the DBA/2J strain (p < 0.00029), thus supporting a predisposition towards tumorigenesis. Most importantly, ectopic expression of miR-290-3p and miR-132 in highly metastatic murine breast cancer cell lines (Mvt-1 and 6DT1) reduced the mammary tumor burden and the number of pulmonary metastasis in FVB/NJ mice after orthotopic injection in the mammary fat pad. Overall, these findings suggest somatic or germline genetic changes that downregulate either miR-132 or miR-290-3p may create a predisposition towards breast cancer development and metastasis.

1. Hurst, D.R., M.D. Edmonds, and D.R. Welch, Metastamir: the field of metastasis-regulatory microRNA is spreading. Cancer Res, 2009. 69(19): p. 7495-8.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3988. doi:10.1158/1538-7445.AM2011-3988
Abstract 3993: Stromal and epithelial microRNA signatures of early breast lesions linked to cancer progression
Authors: Nilsson Sofie , Allred Craig , Howell Anthony , Landberg Göran
Published: June 2012

Columnar cell hyperplasia (CCH) is considered to originate in normal terminal duct lobular units (TDLUs) and is potentially the first histologically identifiable alteration in the development of breast cancer. These lesions have been characterized to have a higher proliferation rate but the underlying mechanisms have not been studied. In order to detect early changes in breast cancer progression we therefore investigated microRNA (miRNA) expression profiles in TDLUs and CCH. Epithelial cells and surrounding stroma of TDLUs and CCH from formalin-fixed paraffin embedded tissue from four patients with high risk of developing breast cancer were laser capture microdissected and RNA was extracted. MiRNA expression profiles were obtained using a qRT-PCR-based array analyzing 667 human miRNAs.

Interestingly, array analysis indicated substantial downregulation of several miRNAs in both the epithelial and the stromal compartments of CCH. MiRNA array analysis of paired samples from specimens with both TDLUs and CCH resulted in significant (p<0.05) decreased levels of 15 miRNAs in epithelial cells of CCH (miR-532-3p, miR-92a, miR-886-3p, let-7c, miR-150, miR-27a, miR-491-5p, miR-130a, miR-365, miR-886-5p, miR-204, miR-135a*, miR-494, miR-29c, miR-768-3p) and downregulation of 18 miRNAs in the stroma (miR-195, miR-296-5p, miR-99a, miR-100, miR-224, let-7c, miR-19b, miR-423-5p, miR-26a, miR-511, miR-128, miR-203, miR-30b, miR-374a, miR-374b, miR-29b, let-7e, miR-10a). We next downregulated miR-27a and miR-92a in a CCH derived cell line and observed a significantly increased proliferation. Opposite effect was observed when the miRs were overexpressed altogether suggesting a proliferative inhibitory function for the selected miRNAs. The miRNA signatures indicate concordant early changes in the epithelial and stromal compartment and the findings could be useful in identifying early key alterations in breast cancer progression that potentially could be targeted in novel prevention or treatment schedules.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3993. doi:10.1158/1538-7445.AM2011-3993
Abstract 3994: Loss of miR-23b enhances Pyk2-induced glioma cell migration and invasion
Authors: Paquette Kimberly M. , Ross Julianna TD , Kloss Jean , Nasser Sara , Yang Zhongbo , Paulino Vincent M. , Kim Seungchan , Loftus Joseph C. , Tran Nhan L.
Published: June 2012

Glioblastoma is the most common and lethal type of primary brain tumor. Despite recent therapeutic advances in other cancers, the treatment of glioblastomas remains ineffective and essentially palliative due the highly invasive nature of the disease. To discern molecular mechanisms that drive GBM migration, we investigated the potential role of differential expression of microRNAs (miRNA) by comparing the matched large-scale, genome-wide miRNA expression profiles of migrating and migration-restricted human glioma cells. Using a radial migration assay, migrating and non-migrating populations from seven well-established glioma cell lines were isolated and utilized for miRNA expression analysis. Statistical analyses revealed 22 miRNAs common to all seven glioma cell lines were down-regulated in the migrating cell population (p < 0.0005) relative to cells in the non-migratory population. Specifically, we report here that the expression level of miR-23b was markedly down-regulated in migrating glioma cells as compared to migration-restricted cells. Over-expression of miR-23b significantly inhibited glioma cell migration and invasion. A bioinformatics search revealed a conserved target site within the 3’untranslated region (UTR) of Pyk2, a non-receptor tyrosine kinase that has been previously implicated in the regulation of glioma cell migration and invasion. Increased expression of miR-23b reduced the expression level of Pyk2 in glioma cells indicating that miR-23b targets Pyk2. Notably, increased expression of miR-23b did not alter the expression level of the related focal adhesion kinase FAK indicating that miR-23b specifically inhibits the expression Pyk2. Taken together, our study demonstrates that reduced expression of miR-23b facilitates the enhancement of glioma cell migration and invasion via modulation of Pyk2 expression. Thus, these data suggest that certain miRNAs may regulate glioma migration and invasion to influence the progression of this disease.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3994. doi:10.1158/1538-7445.AM2011-3994
Abstract 3995: Identification of putative miRNA targets by a systems biological approach in NCI-60 data
Authors: Kim Sangbae , Park Yun-Yong , Park Eun-Sung , Oh Sang-Cheol , Kim Jong-Seung , Sohn Bo-Hwa , Kim Soo-Mi , Davis Michael A. , Mills Gordon B. , Lee Ju-Seog
Published: June 2012

MicroRNAs (miRNAs) are single-stranded, non-coding RNA molecules and on average only 22 nucleotides long that regulate gene expression at the post-transcriptional level. Target predictions of miRNA based on sequence are limited due to too many candidates resulting in high false positives. To overcome this limitation functional target prediction approaches have been investigated by using mRNA and miRNA expression data. These approaches used in the computational assessment of functional miRNA-target association. However, these approaches with miRNA-mRNA association were not enough to verify real functional targets at protein level, which could affect on biological signaling pathway. Therefore, in order to overcome current limitation we developed a novel correlation-based approach (sequence-independence) that predict the association of miRNAs with signaling pathways by using genomics and proteomics data from NCI-60 cancer cell lines (mRNA, miRNA, and protein expression data). To identify miRNA-protein association, we used two correlation-based methods: direct comparison (miRNA-protein pairs) and indirect comparison (miRNA-mRNA and protein-mRNA pairs), then compared their outputs. In direct comparison, we calculated Pearson correlation coefficients for 96k probe pairs and found over 3 k significant correlated pairs (3.2 %) at the cut-off p-value < 0.005: among them 53.4 % were negative and 46.6% were positive. In indirect comparison, we ranked the number of correlated mRNA probes between miRNA-mRNA and protein-mRNA pairs, in which we calculated over 11 and 5.7 million probe pairs respectively. Then, two significant output pair sets were combined by intersection of mRNA probes and then determined the number of common probes. With these determined numbers, finally we generated association score matrix between miRNA and protein probes. Using those score matrix, we evaluated the highly associated miRNAs with 40 biological pathways, which play critical roles in cell cycle, proliferation and metastasis. In conclusion, we developed a noble expression profile-based approach to systematically predict potential miRNA functional targets which play critical roles in cell signaling pathways from the NCI-60 genomic and proteomic data at whole genomic scale.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3995. doi:10.1158/1538-7445.AM2011-3995
Abstract 3997: MiR-181 promotes megakaryocyte differentiation
Authors: Li Xiaobo , Gao Lin , Howell Paul , Owen Laurie , Xi Yaguang
Published: June 2012

MiRNAs have attracted attention due to their key regulatory functions in biological events such as proliferation, differentiation, apoptosis, and tumorigenesis. A few recent studies reported on the existence of a reciprocal regulatory loop between the family of let-7 miRNAs and an RNA-binding protein lin28, both of which play important roles during cell differentiation. Using bipotent K562 human leukemia cells and human CD34+ hematopoietic stem cells as research models, we demonstrate that let-7 and lin28 appear to exhibit inverse expression trends in phorbol ester-induced megakaryocyte differentiation, while miR-181 is up-regulated early during this process. Enforced expression of miR-181a in K562 cells effectively represses lin28 expression, breaking up the lin28-let-7 reciprocal regulatory loop, and sequentially triggers megakaryocyte differentiation as measured by CD41 and CD61 induction. Elevated miR-181 also significantly increases the number of megakaryocyte colonies in CD34+ hematopoietic stem cells. However, miR-181 expression levels only slightly change during hemin-induced erythrocyte differentiation. These results suggest that miR-181 can function as a “molecular switch” during hematopoietic lineage differentiation and can be a potential target for future miRNA-oriented therapeutics for human cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3997. doi:10.1158/1538-7445.AM2011-3997
Abstract 4003: MicroRNA 99b down-regulation in lung cancer tissues leads to fibroblast growth factor receptor 3 up-expression and acceleration of proliferation
Authors: Woong Son Ji , Kwon Sun Jung , Choi Eugene , Na Moon Jun , Jeon Young June
Published: June 2012

Background: Dysregulation of miRNA expression has been identified in a number of cancers and an accumulating data indicate that some miRNAs can function as tumor suppressors or oncogenes and are important in cancer development. Deletion or loss of function of a tumor-suppressing miRNA results in overexpression of target oncogenes. Conversely, activation or overexpression of an oncogenic miRNA results in silencing of tumor-suppressing target genes. According to miRNA profiles on microarray, miR-99b was down-expressed in Korean lung cancer. FGFR-3 is predicted target of miR-99b through two public algorithms. FGFR-3 has been demonstrated to be involved in the RAS/RAF/MEK/MAPK pathway through activation of p90 ribosomal S6 kinase. It has been reported that FGFRs are frequently overexpressed in NSCLC cell lines, suggesting that an FGFR-dependent autocrine signaling pathway may operate in a subset of NSCLCs.

Material & method: We studied expression of miR-99b and FGFR-3 using quantitative reverse transcription PCR (qRT-PCR) in lung cancer tissue. To examine whether miR-99b could regulate FGFR-3 in lung cancer, we performed transient transfection of pre-miR-99b into lung cancer cell line, then we performed qRT-PCR and western blot in HCC1438, HCC95, and H522 cells for analysis of FGFR-3 expression. We hypothesized the miR-99b has a role of inhibitor cell growth in lung cancer. To test this hypothesis, we performed cell proliferation assay.

Results: miR-99b was down-regulated and FGFR-3 was up-regulated in lung cancer. Over-expression of miR-99b induced marked reduction of FGFR-3 mRNA levels and protein level in lung cancer cell line HCC1438, HCC95, and H522. The growth rate in miR-99b precursor treated cell was lower than in negative control of miR treated cell.

Conclusion: Abnormal down-regulation of miR-99b could lead to the over-expression of FGFR-3 in lung cancer. miR-99b may be a potent tumor suppressor and may be a potential candidate of therapeutic tool in lung cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4003. doi:10.1158/1538-7445.AM2011-4003
Abstract 4015: Flavopiridol-induced upregulation of HtrA1 is associated with suppression of its negative transcriptional regulator WT-1 and with enhanced chemosensitivity
Authors: Ohta Tsuyoshi , Khurana Ashwani , Maguire Jacie , He Xiaoping , Chien Jeremy , Bible Keith , Shridhar Viji
Published: June 2012

We previously identified serine protease HtrA1 as a down-regulated gene in epithelial ovarian cancer (EOC) that modulates cisplatin-induced cytotoxicity. However, the mechanism by which HtrA1 sensitizes cells to cisplatin-induced cytotoxicity remained unknown. We have shown previously that the pan-cyclin dependent kinase inhibitor flavopiridol (FP) sensitizes cells to cisplatin-induced cytotoxicity; we hypothesized that flavopiridol might therefore modulate the expression of pro-apoptotic proteins. Microarray data indicated that while flavopiridol treatment alone or in combination with cisplatin up-regulated HtrA1 expression by 2-3 fold (providing a means to upregulate HtrA1 expression), treatment with cisplatin alone had no effect. Interestingly, in searching for underlying mechanisms, we noted that WT-1 transcription factor binding elements that is present in HtrA1 promoter is down-regulated by flavopiridol in our microarray studies. Immunoblot analysis revealed that WT-1 is highly expressed in HtrA1-deficient OV167, OV202, PE04 and Ovcar3 cells but not in HtrA1-expressing SKOV3, TOV21G and PE01 cells, suggesting WT-1 negatively regulates HtrA1 expression in EOC. Immunoblot analysis showed FP treatment resulted in down-regulation of WT-1 with a corresponding increase in HtrA1 protein levels in OV202 cells. Additionally, stable down-regulation of WT-1 by short hairpin RNA (shRNA) in OV202 cells increased HtrA1 expression. Conversely, enhanced expression of full length WT-1 isoform in SKOV3 cells downregulated HtrA1 expression. Reporter assay showed that FP treatment upregulated HtrA1 promoter activity in OV202 cells. Reporter assay and chromatin immunoprecipitation experiments showed that WT-1 is specifically recruited to the HtrA1 promoter. Moreover, downregulation of WT-1 expression in OV202 cells increased cisplatin-mediated cytotoxicity as determined by both 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and clonogenic assays – an effect reversed by enhanced expression of HtrA1. Collectively, our studies demonstrate a linkage between the effects of flavopiridol on HtrA1 and its regulatory transcription factor WT-1 that appears in part to explain why flavopiridol has chemosensitizing properties

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4015. doi:10.1158/1538-7445.AM2011-4015
Abstract 4019: Identification of SOX4 transcriptional target genes in human lung cancer
Authors: Castillo Sandra D. , Medina Pedro P. , Mariani Niccolò , Sanchez-Cespedes Montse
Published: June 2012

The search for novel oncogenes is becoming increasingly important in cancer genetics because they are suitable targets for therapeutic intervention. Our current work lays in study the role of the SOX4 transcription factor in human lung carcinogenesis. The SOX4 gene belongs to a large family of transcription factors related by homology in their DNA-binding domain and is predominantly expressed during embryonic development in heart, central nervous system, lung and thymus. SOX4 has been proposed as a candidate oncogene in many types of cancer such as bladder, prostate, colon, urothelial, adenoid cystic carcinoma and lung because of its increased expression in those tumors. Previous studies in our lab uncovered SOX4 gene amplification and concomitant over-expression in a subset of lung primary tumors and cancer cell lines. Interestingly, SOX4 expression was significantly greater in the SCLC cell lines.

Little is known about the transcriptional targets and pathways orchestrated by SOX4 during lung carcinogenesis. To further investigate SOX4 contribution to lung carcinogenesis we developed an inducible short-hairpin system in the NCI-H522 lung cancer cell line, which is known to carry SOX4 gene amplification and over-expression, in order to abrogate SOX4 expression in an inducible manner. Then, we performed an expression analysis using the Whole Human Genome Oligo Microarray platform from Agilent which represents over 41000 genes and transcripts to elucidate the differential gene expression when knocking down SOX4. We found about 150 genes and transcripts with more than 2 fold-change of expression. Afterwards, we confirmed the array data by real time quantitative PCR (RT-qPCR) of the genes with a decreased expression when interfering SOX4 mRNA. Within these genes, we could confirm direct transcriptional targets of SOX4 by means of binding site computation and quantitative chromatin immunoprecipitation (qChIP). This integrated approach helps us to better understand the role of SOX4 in lung carcinogenesis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4019. doi:10.1158/1538-7445.AM2011-4019
Abstract 4022: Inactivation of the tumor suppressor BRG1 in lung cancer: Influence on nuclear receptors and cell differentiation
Authors: Romero-Ferraro Octavio A. , Setién Fernando , Villanueva Alberto , Coll Albert , Sanchez-Cespedes Montserrat
Published: June 2012

BRG1, encoding an ATPase of the SWI/SNF chromatin remodelling complex, is genetically inactivated in a variety of human solid tumors, especially non-small cell lung cancer, thus, constituting a bona fide tumor suppressor gene. However, the mechanisms that mediate the tumor suppressor function of BRG1 are not completely elucidated. We previously reported that lung tumors with amplification at any of the MYC family of genes lacked BRG1 mutations, suggesting a functional relationship between both proteins. Using isogenic lung cancer cell lines, that stably and conditionally express wild type or mutant BRG1, we found that wtBRG1 induced the up-regulation of MYC-target genes. This was accompanied by a reduction in MYC levels. Interestingly, we observed an overlap in the gene expression pattern after restoring wtBRG1 in lung cancer cells and gene expression in normal lung, indicating that BRG1 is promoting cell differentiation. In addition, the effects of BRG1 activity in lung cancer cells, i.e. changes in morphology and in gene expression depended on the presence of specific vitamins/hormones. Exposition to these compounds conferred lung cancer cells specific morphological features that were compatible with cell differentiation, only after restoring wtBRG1. Finally, using lung orthotopic mouse models we demonstrated that BRG1 was able to cause significant tumor shrinkage and delay tumor progression. Taken together our data support a tight functional relationship between BRG1 and MYC by which inactivation of BRG1 in cancer cells leads to de-regulation of MYC activity and allow refractoriness to nuclear receptor-mediated external signals impairing the control important cellular processes, such as cell differentiation, proliferation and response to inflammation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4022. doi:10.1158/1538-7445.AM2011-4022
Abstract 4027: Myc controls mRNA stability through the agency of AU-binding proteins to promote lymphomagenesis
Authors: Rounbehler Robert J. , Fallahi Mohammad , Steeves Meredith A. , Li Weimin , Yang Chunying , Doherty Joanne R. , Cleveland John L.
Published: June 2012

Myc oncoproteins regulate transcription by binding to target genes harboring E-boxes or Initiator elements, yet these responses explain only a fraction of the genes Myc affects. mRNA turnover is controlled via binding of AU-binding proteins (AUBPs) to AU-rich elements (AREs) found within many transcripts. Expression analyses of precancerous and malignant Myc-expressing B cells revealed Myc regulates hundreds of ARE-containing genes and several AUBPs. Notably, Myc directly suppresses transcription of Tristetraprolin (TTP), an mRNA-destabilizing AUBP, and TTP suppression is a hallmark of Myc-driven lymphoma in mice and man. Furthermore, TTP has profound effects on tumorigenesis, where restoring TTP impairs Myc-induced lymphoma development and abolishes maintenance of the malignant state; thus, TTP functions as a tumor suppressor. Finally, the Myc-to-TTP pathway regulates a very select cast of ARE-containing genes that control cell proliferation and transformation. Thus, Myc utilizes AUBPs to target ARE-containing genes in its efforts to control cell fate and transformation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4027. doi:10.1158/1538-7445.AM2011-4027
Abstract 4029: Inhibitor of differentiation 4 (Id4) Induces of senescence, apoptosis and cell cycle regression in prostate cancer
Authors: Carey Jason P. , Chaudhary Jaideep , Evans Ashley
Published: June 2012

Id4 is a member of helix loop helix (HLH) transcriptional regulator family. Unlike its other family members (Id1, 2 and 3) that promote metastasis, proliferation and invasion (tumor promoter). Id4 essentially acts as a tumor suppressor e.g. Id4 expression is lost in prostate cancer through promoter hypermethylation. However the underlying mechanism by which Id4 acts as a tumor suppressor remains to be determined. In order to investigate the molecular mechanism by which Id4 acts as a tumor suppressor, we used DU145 cell in which Id4 is epigenetically silenced. Ectopic expression of Id4 in DU145 cells resulted in the induction of several cellular processes that are reminiscent of its role as a tumor suppressor. Our results suggested that Id4 is directly linked to cell cycle control, apoptosis, senescence and induction of epithelial like morphology. There is also an upregulation in androgen receptor expression, localization to the nucleus and an atypical response to androgens in DU145 prostate cancer cells. FACS analysis using a combination of PI and Annexin V staining demonstrated the ability of Id4 to induce an S-phase arrest, and initiate apoptosis. Interestingly, Id4 promoted senescence as observed by beta-galactosidase staining. RT-PCR and western blot analysis were used to study the gene expression of apoptosis and cell cycle control genes such as: E-cadherin, p21, p27, p53, MDM2, E2F1 and, Androgen receptor. The S-phase arrest in Du145+Id4 cells was E2F-1 dependent. The increased expression of E-cadherin, p27, p21 and MDM2 in DU145+Id4 cells strengthen the hypothesis that Id4 acts as a tumor suppressor by regulating key cell cycle control and apoptosis associated genes. Re-expression of functional androgen receptor marked a dramatic change in the androgen independent prostate cancer cell type. Thus, Id4 appears to induce a total cellular reprogramming and reversal of the cancer phenotype, by influencing key regulatory pathways.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4029. doi:10.1158/1538-7445.AM2011-4029
Abstract 4032: SIRT1 modulates E2/ERα-associated oncogenic signaling in human breast cancer
Authors: Elangovan Selvakumar , Ramachandran Sabarish , Prasad Puttur D. , Ganapathy Vadivel , Thangaraju Muthusamy
Published: June 2012

SIRT1, a NAD+-dependent deacetylase, first emerged as a potential anti-aging factor by controlling senescence, but now it is also implicated in tumor development and cancer cell survival. SIRT1 is overexpressed and/or catalytically activated in a variety of human cancers, suggesting a potential role for SIRT1 in tumor promotion. SIRT1 promotes oncogenic signaling, in part, by deacetylating the tumor suppressor protein p53 resulting in its inactivation. Similarly, estrogen receptor alpha (ERα) also promotes the development and progression of hormone-dependent cancers such as breast cancer, in part, by inactivating p53 function. It is not known whether ERα and SIRT1 functionally cooperate to elicit their biologic effects. Thus, we hypothesized that there could be a functional link between ERα and SIRT1 and that this link could play a role in cellular immortalization and tumor formation in mammary epithelial cells. Using a series of coimmunoprecipitation and immunofluorescence assays, we demonstrated that ERα physically interacts and functionally cooperates with SIRT1 in breast cancer cells and that SIRT1 is necessary for ERα-induced p53 inactivation. This interaction requires active estrogen-ERα (E2-ERα) complex and catalytically active SIRT1. Functional disruption of either E2-ERα or SIRT1 dramatically reduces this interaction. Further, ERα binds to SIRT1 promoter and increases SIRT1 transcription whereas SIRT1 does not affect the expression and acetylation status of ERα. In breast cancer cells, SIRT1 inactivation or knockdown decreases E2-induced cell growth, and this process is associated with prevention of ERα-induced p53 inactivation and induction of antioxidant enzymes. Finally, mouse xenograft studies of human ER-positive breast cancer cells provide in vivo evidence for the importance of the ERα-SIRT1 complex in breast cancer growth in which deletion of SIRT1 abrogates the tumor-promoting activity of estrogen completely. These studies show that SIRT1 is essential for the promotion of E2/ERα-associated breast cancer growth and that a combination of SIRT1 inhibitors and anti-estrogens could offer a novel approach for breast cancer management.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4032. doi:10.1158/1538-7445.AM2011-4032
Abstract 4033: Identification and characterization of a truncated RUNX3 gene variant with putative dominant-negative function
Authors: Lau Wen Min , Chong Hui Shan , Lopez Kirsten Anne Pagaduan , Teng Eileen , Chan Shing Leng
Published: June 2012

Stem cells and cancer stem cells show a distinct proliferative potential for forming clonal floating colonies in vitro, termed tumor spheres. We have generated tumor spheres from a clinical gastric cancer sample (GCIC38) using serum-free culture, and expression of EpCAM and cytokeratin proteins confirmed the epithelial origin of these cells. GCIC38 sphere-derived cells were able to initiate tumors in NOD/SCID mice that recapitulate the tumor in the gastric cancer patient. Real-time PCR analysis showed that in contrast to human gastric cancer cell lines AGS, SNU16 and NCI-N87, GCIC38 sphere-derived cells express relatively high levels of stem cell markers such as SOX2, Musashi-1, and Bmi-1. Surprisingly, mRNA expression of the well-known tumor suppressor for gastric cancer, RUNX3, was found to be 4.6 and 16-fold higher than that of SNU16 and NCI-N87 cells respectively. Consistently, western blot analyses showed that GCIC38 sphere-derived cells express high levels of RUNX3 compared to a panel of gastric cancer cell lines. Immunofluorescence staining confirmed that RUNX3 was expressed in the nuclei of these cells, ruling out the possibility of RUNX3 protein mislocalization. To further characterize RUNX3 in GCIC38 sphere-derived gastric cancer cells, we cloned and identified a novel truncated 0.4kb RUNX3 variant (RUNX3-LG) that is expressed concurrently with the 1.2kb full length RUNX3 transcript (wt-RUNX3) in these cells. Sequence analysis revealed that RUNX3-LG is a truncated form of RUNX3 variant 2 encoded by a transcript utilizing the P2 promoter. There are no mutations in the wt-RUNX3 transcript whilst exons 3, 4 and 5 are spliced out in the RUNX3-LG transcript resulting in the deletion of RUNT domain in the RUNX3-LG protein. Immunoprecipitation studies using RUNX3 antibodies showed endogenous expression of a 15kDa protein in GCIC38 sphere-derived cells, concordant with the predicted size of RUNX3-LG protein. Preliminary data show that ectopic over-expression of RUNX3-LG in AGS gastric cancer cells results in reduced expression of RUNX3 target genes Claudin-1, S100A2 and p21. We propose that RUNX3-LG may be a dominant negative variant in gastric cancer cells with high wt-RUNX3 expression, which may abrogate wt-RUNX3 gene function including its tumor-suppressive effects.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4033. doi:10.1158/1538-7445.AM2011-4033
Abstract 4036: Chromosomal amplification of LRRK2 is required for oncogenic MET signaling in papillary renal and thyroid carcinomas
Authors: Looyenga Brendan D. , Furge Kyle A. , Dykema Karl J. , Koeman Julie , Swiatek Pamela J. , Giordano Thomas J. , West Andrew B. , Resau James H. , Teh Bin T. , MacKeigan Jeffrey P.
Published: June 2012

The receptor tyrosine kinase MET is frequently amplified in human tumors, resulting in high cell surface densities and constitutive activation even in the absence of growth factor stimulation by its endogenous ligand, HGF. We sought to identify mechanisms of signaling crosstalk that promote MET activation by searching for kinases that are coordinately dysregulated with wild-type MET in human tumors. Bioinformatic analysis identified leucine-rich repeat kinase-2 (LRRK2), which is amplified and overexpressed in papillary renal and thyroid carcinomas. Downregulation of LRRK2 in cultured tumor cells compromises MET activation and selectively impairs MET signaling to mTOR and STAT3. Loss of these critical mitogenic pathways induces cell cycle arrest and cell death concomitant with loss of ATP production and induction of autophagy. Interestingly, knockdown of LRRK2 precisely phenocopies treatment of tumor cells with the endocytic inhibitor chlorpromazine, suggesting that LRRK2 is required for efficient internalization or post-endocytic trafficking of activated MET receptors. We propose that coordinate amplification of LRRK2 and MET functions to promote endosomal signal transduction by MET, which is required for transformation in papillary renal and thyroid cancers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4036. doi:10.1158/1538-7445.AM2011-4036
Abstract 4038: Aspirin acetylates p53 in colon cancer cells and induces the expression of p21 and Bax: Identification of aspirin acetylated sites on rp53
Authors: Chivukula Raghavender , Marimuthu Srinivasan , Alfonso Lloyd , Hagen Fred , Gunaje Jayarama B.
Published: June 2012

Several studies over the past decade have shown that regular use of aspirin reduces the risk of cancers of various organs such as colon, breast, lung and prostate tissue. The mechanism by which aspirin exerts its anti-cancer effects is not clearly understood. Previous studies from our laboratory showed that aspirin acetylates the tumor suppressor protein p53 and modulates target gene expression in MDA-MB-231 breast cancer cells. We now have extended these studies to include HCT116 (wt-type p53) and HT-29 (mutant p53) colon cancer cells. Using anti-acetyl p53 antibody, we show in the present study that aspirin acetylated p53 at lysine 382 in both cell types. It also detected two other proteins of size 63 kDA and 35 kDa, which are likely to represent other isoforms of p53. Aspirin also acetylated recombinant p53 (rp53) in vitro, suggesting that the mechanism of cellular acetylation may be through a direct non-enzymatic chemical reaction. Mass spectrometry analysis of the aspirin-treated rp53 identified 7 acetylate lysine residues. In HCT116 and HT-29 cells, aspirin-induced acetylation of p53 was observed in a concentration dependent manner. The acetylated p53 was localized to the nucleus. Consistent with these observations, aspirin transiently increased p21, a protein involved in cell cycle arrest; however, the expression of the proapoptotic protein, Bax, was sustained. Treatment of cells with the anti-cancer drug, camptothecin, induced sustained induction of p21. Co-treatment with both camptothecin and aspirin decreased the expression of p21. Aspirin also potentiated camptothecin-induced cell death as measured by MTT assay, clonogenic cell survival assay and annexin V binding assay. Our results suggest that p53 pathway may contribute to the anti-cancer properties of aspirin.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4038. doi:10.1158/1538-7445.AM2011-4038
Abstract 4042: Activation of ErbB2 results in decreased Par6-associated aPKC kinase activity
Authors: Krishnamurthy Kannan , Aranda Victoria , Muthuswamy Senthil
Published: June 2012

Loss of epithelial cell polarity is often associated with the development of carcinoma. Polarized MDCK cells and MCF-10A mammary epithelial cells grown in 3D are useful model systems to study the regulation of cell polarity in vitro and to investigate the interaction of oncogenes and cell polarity proteins. Using these experimental models, we have previously demonstrated that activation of the oncogene ErbB2 disrupts apical-basal polarity in mammary epithelial cells. Activated ErbB2 associates with the Par6-aPKC polarity complex and the interaction between Par6 and aPKC is indispensible for ErbB2-mediated disruption of cell polarity and inhibition of apoptosis. Following ErbB2 activation, we find a decrease in Par6-associated aPKC kinase activity. Furthermore, kinase dead aPKC cooperates with activated ErbB2 to transform mammary epithelial cells in vitro, without inducing any changes in proliferation of cells grown on plastic dishes. Taken together, our data implicate a target (or targets) of aPKC as a likely determinant of ErbB2-mediated disruption of cell polarity and transformation. Identification of these substrates could lead to the development of novel biomarkers to monitor the progression of ErbB2 positive tumors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4042. doi:10.1158/1538-7445.AM2011-4042
Abstract 4242: Clinically used nitrocatechols and EGCG synergistically inhibit lung cancer cells in vitro
Authors: Forester Sarah C. , Lambert Joshua D.
Published: June 2012

Polyphenols are likely to be responsible for the anticancer effects of green tea, with (−)-epigallocatechin-3-gallate (EGCG) the most well-studied. EGCG reduces lung cancer cell viability effectively in vitro, yet it is methylated by catechol-O-methyl transferase (COMT), limiting its effectiveness in inhibiting cancer cell growth. The nitrocatechol drugs entacapone and tolcapone are potent inhibitors of COMT and are used to mitigate effects of Parkinson's disease. Here, we investigated the synergistic effects of entacapone/tolcapone and EGCG in human (H1299) and murine (CL-13) cell lines. The IC50s of entacapone, tolcapone, and EGCG were 76.8, 29.3, and 174.9 μM, respectively in H1299 cells, and 50.7, 19.7, and 181.5 μM, respectively in CL-13 cells following treatment for 72 h. The IC50s were dramatically reduced when entacapone and tolcapone were used in combination with EGCG. The interactions were determined to be synergistic using isobolographic analysis. Inhibition of COMT-mediated methylation of EGCG by entacapone and tolcapone was also measured by LC-MS over 30 min and the IC50 values were 10 and 20 μM, respectively. The anticancer effects of the nitrocatechols and EGCG were also evaluated in pathways of apoptosis (TUNEL) and cell cycle (flow cytometry). In conclusion, the combination of EGCG and entacapone or tolcapone has greater lung cancer growth inhibitory activity than treatment with any of the single compounds. The mechanistic basis for this synergy is likely due in part to COMT inhibition, yet other mechanisms are also likely to play a role. Funded by NIH grant AT004678.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4242. doi:10.1158/1538-7445.AM2011-4242
Abstract 4243: Potential protective role of phytoalexins derived from soybean by biotic elicitor on inflammatory mechanism
Authors: Kim Hyo Jung , Jung Chae Lim , Nam Dae Hwan , Lim Ji Sun , Han Min Young , Hong Ye-Seul , Kim Jong-Sang
Published: June 2012

Given the preventive effect of soy intake against several chronic diseases, this study was conducted to investigate the inhibitory activity of phytoalexins glyceollins derived from soybean isoflavones by treating with biotic elicitor against LPS-induced inflammation in RAW 264.7 cell culture system. Our data showed that glyceollins effectively inhibited NO production, IL-6 release, and COX-2 expression induced by LPS. In particular, glyceollins suppressed the LPS-induced phosphorylation of NF-B p65, suggesting that the compounds inhibit the production of NO and transcriptional activation of COX-2 by regulating NF-B activity. In another experiment we found that glyceollins enhanced the expression of heme oxygenase 1 and repressed the phosphorylation of ERK1/2 and p38 but not JNK in LPS-treated RAW 264.7 cells. Glyceollins also reduced TPA-induced skin inflammation in mouse model, confirming the anti-inflammatory activity of glyceollins in vivo system as well as cell culture system. Taken together, glyceollins merit further study as potential therapeutic agents for inflammatory disorders.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4243. doi:10.1158/1538-7445.AM2011-4243
Abstract 4245: Preclinical study of puquitinib, a novel orally available PI3K inhibitor in phase I clinical trials
Authors: Xie Chengying , Xu Yongping , Lou Liguang
Published: June 2012

Extensive evidence implicates activation of PI3K pathway in the genesis and progression of various human cancers. PI3K inhibitors thus have considerable potential as molecular cancer therapeutics. In this report, we detailed the pharmacologic properties of puquitinib, a novel orally available PI3K inhibitor structurally distinct from all those known so far. Puquitinib reduced the levels of phosphatidylinositol-3,4,5-trisphosphate (PIP3), a product of PI3K, and inhibited the phosphorylation, translocation and membrane ruffling of AKT, the signaling component downstream from PI3K. The inhibitory effects of puquitinib on PI3K signaling were correlated with its potent anti-proliferative activity in a panel of tumor cells. Puquitinib also demonstrated potent anti-angiogenic effects in the tubule formation and cell migration assays of human umbilical vein endothelial cells, and micro-vessel spouting from matrigel-embedded rat aortic rings. Oral administration of puquitinib showed strong antitumor activity in various human cancer xenograft models without any noticeable toxicity, along with the reduction of phosphorylated AKT in tumor tissues. Collectively, the preclinical data show that puquitinib is a potent PI3K inhibitor with favorable pharmaceutical properties. Puquitinib is currently being evaluated in phase I clinical trials in China.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4245. doi:10.1158/1538-7445.AM2011-4245