bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1986: RAS signaling is the key factor determining differential response to PI3K and MAPK targeting compounds in a panel of breast cancer cell lines
Authors: Feldman Igor , Zhang Theresa , Nebozhyn Michael , Ayers Mark , Paweletz Cloud , Lynch Bethany , Arthur Bill , Roberts Brian , Strack Peter , Shumway Stuart , Chen Albert , Chastain Mike , Huang Pearl , Dai Hongyue , Watters James , Loboda Andrey
Published: February 2011

We have tested PI3K and MAPK targeting compounds in a panel of 69 breast cancer cell lines. Following the molecular stratification of breast cancer tumors, we have used ER and HER2 biomarkers to stratify cell lines into HER2 positive (HER2+), ER positive (ER+), and triple negative (TN; ER-, PR- and HER2-) subgroups. Both gene expression and response to compounds showed significant differences among the subtypes. Response to mTOR and AKT inhibition was the greatest in ER+ and HER2+ groups (86%, 85% for mTORi and 64%, 77% for AKTi response rates, respectively), whereas TN cell lines showed preferential sensitivity to MEK inhibition (30%). The combination of AKT plus MEK and mTOR plus MEK inhibitors showed synergy in TN tumors (56% and 80% response rates, respectively), particularly in the epithelial subgroup. We believe that RAS pathway deregulation, as reported by a gene expression signature of RAS activation, is the key latent variable that explains the difference in responses. This conclusion is based on pathway activation differences between subtypes. We observe that the TN group has both elevated PI3K and MAPK signaling, evident by high levels of RAS, pERK, and pMEK signatures, whereas the ER+/GGI+ group only has high levels of PI3K signaling. Thus, mTOR, AKT, or MEK alone is insufficient to inhibit the TN lines, whereas the combos are very effective. Finally, we have assessed the prevalence of the EMT and RAS signatures across subtypes of breast tumors. Similar to cell lines, the RAS signature is markedly higher in TN compared to ER+/GGI+ and, to a lesser extent, compared to HER2+ tumors. The EMT signature on the other hand is not significantly different among subtypes. This would suggest that the response patterns observed in ER+/GGI+ and TN/E subtypes of this breast panel will be applicable to a substantial subpopulation of breast tumors (∼38%). Importantly, these breast subtypes represent the largest unmet need and are a high priority for the clinical oncology.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1986.
Abstract 1988: In silico estimates of cell components in cancer tissue based on expression profiling data
Authors: Wang Yipeng , Xia XiaoQin , Jia Zhenyu , Sawyers Anne , Yao HuaZhen , Wang-Rodriquez Jessica , Mercola Dan , McClelland Michael
Published: February 2011

Cancer gene expression profiling studies often measure samples that vary widely in the mixtures of cell types they contain. Such variation could confound efforts to correlate expression with clinical parameters. In principle, the proportion of each major tissue type can be estimated from the profiling data and used to triage samples before using the data to study correlations with disease parameters. Four large gene expression microarray data sets from prostate tissue whose cell components were estimated by pathologists were used to test the performance of in silico prediction of tissue components. Multi-variate linear regression models were developed for in silico prediction of major cell components of prostate cancer tissue. 10-fold cross-validation within each data set gave average differences between the pathologist and in silico predictions of 8∼14% for the tumor component and 13∼17% for stroma component. Across data sets that used similar platforms and fresh frozen samples, the average differences were 11∼12% for tumor and 12∼17% for stroma. Prediction models were applied to expression data on the same platform from 219 other tumor-enriched prostate cancer samples for which tissue proportions were not known. The tumor “enriched” samples were predicted to have a wide range of tumor percentages; 0 to 87%. Furthermore, there was a 10.5% difference in the average predicted tumor percentages between 37 recurrent and 42 non-recurrent cancer patients. This systematic difference in tumor content would likely cause tissue-specific gene changes to falsely appear to be correlated with recurrence unless some samples were excluded to remove this bias or unless tissue percentages were incorporated into the prediction model. Similar circumstances may arise in other sets of clinical samples. A web service, CellPred, has been designed for the in silico prediction of prostate cancer sample cell components. While this site is currently based on microarray data, it could equally well use high-throughput sequencing data. The approach presented here can be generalized to other tissue mixtures once data on both tissue content and expression profiles are obtained for a training set. CellPred is freely available at http://www.webarraydb.org/.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1988.
Abstract 1989: Gene expression signature of the non-cancerous liver tissue associated with the early recurrence of hepatocellular carcinoma
Authors: Tanaka Shinji , Mogushi Kaoru , Yasen Mahmut , Noguchi Norio , Irie Takumi , Kudo Atsushi , Nakamura Noriaki , Inazawa Johji , Tanaka Hiroshi , Arii Shigeki
Published: February 2011

Recurrence of hepatocellular carcinoma (HCC) might be associated with biological aggressiveness of the cancer as well as background status of the liver. In this study, the predictive values for the early recurrence were assessed on patients with HCC after curative hepatectomy using clinicopathological factors and genome-wide gene expression signatures. Multivariate analysis of clinico-pathological factors revealed portal vein invasion (p=0.007), hepatitis C virus infection (p=0.001), and low levels of serum albumin (p=0.003) as the risk factors, yielding a ROC-plot AUC value of 0.854 with 61.5% sensitivity and 81.8% specificity. Analysis of the gene expression profiling on the cancer tissues of HCC revealed the significant differences in CD24 stem cell marker and MTSS1 metastasis suppressor molecule. The cancer six-gene signature for the prediction of recurrence yielded a ROC-plot AUC value of 0.897 with 81.8% sensitivity and 88.5% specificity. Using the non-cancerous liver tissues surrounding HCC, distinct differences were recognized by the gene expression profiling such as IGL immunoglobulin lambda light chain and MAP2K1 mitogen-activated protein kinase kinase. The non-cancer six-gene signature yielded a ROC-plot AUC value of 0.966 with 84.8% sensitivity and 88.5% specificity for the prediction of HCC recurrence. These gene expression signatures can be involved in the metastatic potentials of the invasive HCC, and the multi-centric hepatocarcinogenesis, respectively. Our results might indicate the molecular targets for prediction and/or treatment of the recurrence, as well as the super-high risk group of HCC within the patients with hepatitis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1989.
Abstract 1993: Higher activity of cell proliferation is associated with poor survival in lung adenocarcinoma
Authors: Lu Jo-Yang , Hsiao Tzu-Hung , Peck Konan , Chuang Eric Y. , Lai Liang-Chuan
Published: February 2011

The number of patients with lung adenocarcinoma, a major histological type of lung cancer, has soared recently. Although some lung adenocarcinoma patients could be diagnosed at early stages and received surgical resection, nearly 50% of patients still died from recurrence. This phenomenon indicates that using only traditional prognostic factors, like TMN staging, is not sufficient for regimen decision. Here we proposed a bioinformatic method to evaluate the activity of cell cycle from expression profiles and proved that the activity of cell cycle can be applied as prognostic factor of lung adenocarcinoma, especially for early stages.

A gene set named as cell cycle signature (CCS), which correlated with cell cycling, was used to measure the activity of tumor proliferation. The E2F1 target genes and E2F3 target genes were also applied to measure the E2F signaling pathway activity, which was regulated by the cell cycle. The prognostic ability of these gene sets was evaluated by applying Cox hazard proportional analysis to three microarray datasets of lung adenocarcinoma.

Our result revealed that the association between high activities of cell cycle and poor survival outcomes existed in lung adenocarcinoma patients. The result of Cox hazard proportional analysis showed that the CCS and E2F1/E2F3 target genes are significant contributors to survival risk. The p-values of CCS, E2F1/E2F3 target genes were all showed significant (p<0.05), and these three gene sets still gave statistical significances after the survival analysis was applied on only early stage lung adenocarcinoma. The hazard ratios of CCS, E2F1 target genes and E2F3 target genes were 5.69, 3.32, and 3.96, respectively; all p-values were smaller than 0.002.

We demonstrated that the three gene sets, which accountable for the activity of cell cycle, can be applied as prognostic factors for lung adenocarcinoma, including early stage patients. Our data inferred that tumor with higher activity of proliferation is malignant eventhough its size may still be small. This finding is valuable in predicting the survival of early stage lung adenocarcinoma patients and might be useful for making treatment decisions.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1993.
Abstract 1994: Mediators responsible for the invasive progression of superficial bladder cancers
Authors: Seol So-Young , Lee Sang-Yop , Kim Seong-Gi , Leem Sun-Hee , Chu In-Sun
Published: February 2011

Bladder cancer is seventh most prevalent type of cancer worldwide and accounts for an estimated 150,000 deaths annually. Urothelial carcinoma of the bladder accounts for more than 90% of bladder cancers. This cancer presents as a heterogeneous disease that consists of two main phenotypic groups with distinct biological behaviors and prognoses: Approximately 80% of patients have tumors that are superficial or non-muscle invasive, and the remaining 20% of tumors presents as a muscle-invasive tumor with dismal prognosis. After early treatment by surgical resection and intravesical immunotherapy, around 20% of these patients have disease progression to invasive tumors and eventually die of the disease. Current methods of predicting the clinical behavior of these tumors prospectively are unreliable. Due to the progress of superficial bladder cancer into invasive bladder cancer, a development of marker that could identify superficial cancers with a high risk of progression is needed. In our microarray analysis from 165 bladder cancer patients, supervised analysis of gene expression data revealed a gene expression signature that is strongly associated with invasive bladder tumors. Gene network analyses of the signature revealed that E2F1 and its downstream effectors EZH2 and SUZ12 could be important mediators for the invasive and metastatic progression of superficial tumors. Furthermore, we investigated how these genes may affect the invasive and metastatic progression of superficial tumors. We investigated the invasive ability by these genes in two groups of bladder cancer cell lines: One group (UC9 and UC14) has a superficial signature of bladder cancer, and the other group (EJ and UC13) has an invasive signature of bladder cancer. We examined the effects of overexpression or siRNA inhibition of these genes on cell growth, wound healing migration and invasion in bladder cancer cell lines. We will report the results estimating the roles of these genes for the invasive and metastatic progression in bladder cancer cell lines.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1994.
Abstract 200: Methylation of GATA4 and GATA5 transcription factor genes in gastric cancers
Authors: Akiyama Yoshimitsu , Nagasali Hiromi , Kawamoto Ayako , Herman James G. , Baylin Stephen B. , Yuasa Yasuhito
Published: February 2011

GATA factors comprise a small family of transcription regulatory proteins containing two conserved zinc finger DNA binding domains for the consensus sequence (WGATAR). Among the six GATA factors, GATA-1/2/3 factors are prominently expressed in the hematopoietic cell lineage, while GATA-4/5/6 factors show a partly overlapping expression pattern in the heart and endoderm-derived organs. We previously reported that GATA4 and GATA5 were silenced by their promoter hypermethylation in gastrointestinal, lung and ovarian cancers. However, it remains unknown the mechanism underlying loss of GATA transcription factors in gastric carcinogenesis. To clarify the role of GATA, we examined GATA4/5 methylation and their downstream target genes in gastric cancer (GC). By using methylation specific PCR, the methylation frequency of GATA5 (30, 39%) was significantly higher than that of GATA4 (10, 13%) in 77 GC tissues (P<0.01). However, methylation of GATA6 was not observed in GCs examined. We transiently over-expressed GATA4 or GATA5 in GC cell lines lacking their expression by aberrant methylation. Both GATA4 and GATA5 suppressed colony formation and cell proliferation in MKN74 cells. After GATA4/5 over-expression in MKN74 and KATO-III cells, enhanced expression of numerous genes including ones indicating tumor-suppressive functions, such as TFF1, disabled-2 and IQGAP2, was observed by microarray and RT-PCR analyses. The target genes of GATA4 and GATA5 were closely similar in MKN74 cells. We also preformed siRNA transfection of GATA4 and GATA5 in AGS and HSC43 cells which basally expressed them. Reduced expression of above predicted GATA target genes was detected in these two cell lines after siRNA transfection. These data suggest that loss of GATA4 and GATA5 expression may contribute to gastric carcinogenesis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 200.
Abstract 2021: MicroRNA affinity assay
Authors: Shi Miao , Han Weiguo , Spivack Simon
Published: February 2011

Introduction: MicroRNAs (miRNAs) are small noncoding RNAs functioning in gene regulation. In animal cells, miRNAs bind to target sites in the 3’ UTR of mRNAs, causing posttranscriptional repression or degradation of mRNAs. The identification of specific miRNAs to target a 3′UTR of a given gene is essential for studies in gene regulation. However, the sequence software programs conventionally used to predict binding of individual microRNAs to a given mRNA transcript are notoriously unreliable, and specific microRNA-mRNA binding is very difficult to directly affirm using currently available techniques. We have developed a microRNA affinity assay that addresses this need. Methods: We chose a candidate gene that had been extensively studied experimentally for microRNA regulation; it is known that miR-200c and miR-200b can bind to 3′UTR RNA of TCF8 [Hurteau 2007]. Here, a 500bp fragment of the 3′UTR RNA of TCF8 was generated by IVT, and used as a bait sequence to identify miRNAs that bind a mixture of known miRNA composition, and alternately a naturally produced cellular miRNA pool. After separation, miRNA qPCR was used to check recovery rate of miRNA, and cloning and sequencing was used to identify miRNAs. Results: Specific miRNAs from a synthetic mixture miRNAs, miRNA qPCR results displayed excellent recovery rates (151.57% with pipetting error, for miR-200c), 88.88% for the closely related miR-200b, 0.31% for the sequence-unrelated miR-9, 0.67% (miR-10a), 0.1% (miR-20a), 8.78% (miR-34a with some 3′UTR homology), 0.11% (miR-100), 0.16% (miR-140-5p), 0.98% (miR-144), 0.33% (miR-802) and 1.58% (miR-1234). After cloning the captured miRNAs, there were 10 sequences from miR-200c, 7 sequences from miR-200b, and one other sequence in 18 sequenced clones. When separating specific miRNAs from naturally produced NHBE cell miRNA pool, miRNA qPCR results show that their recovery rates are 88.88% (miR-200c), 80% (miR-200b), 0.07% (miR-20a), less than 0.006% (miR-34a) and 0.01% (miR-100). Conclusions: For both simple known and complex unknown microRNA pools, this pull-down strategy is effective in determining microRNA-mRNA binding. In future work, we will use other 3′UTR RNA sequences of candidate genes as bait sequence, for microRNA-related discovery and confirmation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2021.
Abstract 2025: Let-7 family miRNAs regulate estrogen signaling pathways mediated by ER alpha-66 and ER alpha-36 in breast cancer
Authors: Zhao Yingchun , Deng Caishu , Wang Jiarui , Xiao Jing , Zhang Hongwei , Gatalica Zoran , Recker Robert , Xiao Gary G.
Published: February 2011

To understand how microRNAs (miRNAs) regulate breast cancer tumorigenesis, a miRNA expression microarray screening was performed using RNAs from formalin-fixed paraffin-embedded (FFPE) breast tissues, which included benign (n=13), ductal carcinoma in situ (DCIS) (n=16), and invasive ductal carcinoma (IDC) (n=15). Twenty miRNAs that were differentially expressed (p<0.01) were identified, of which let-7 family miRNAs were down-regulated in human breast cancer tissues at stages of DCIS and IDC compared to benign stage. To understand the role of let-7 miRNAs further, we performed bioinformatics analysis and found that let-7 miRNA sequences match sequences in the 3’-UTRs of estrogen receptor alpha 66 (ER-α66) and another novel receptor ER-α36. The targeting of let-7 miRNAs on ER-α66 and ER-α36 was further confirmed by a number of experimental assays, including luciferase assay, protein expression, and mRNA expression. Overexpression of let-7 miRNAs in ER-α66-positive breast cancer MCF7 cell line negatively affected ER-α66 mediated genomic estrogen pathway. As expected, down-regulation of the ER-α66 signaling by let-7 miRNAs inhibited cell proliferation, and subsequently triggered the cell apoptotic process in MCF7 cells. On the other hand, overexpression of let-7 miRNAs in ER-α66-negative cell line MB-MDA-231 negatively affected ER-α36 mediated non-genomic estrogen pathway. Besides, down-regulation of let-7 is correlated with up-regulation of ER-α36 in tamoxifen (Tam) and ICI-182780 (ICI) resistance in MCF7 cell line. Forced overexpression in Tam-and ICI-resistant MCF7 cells dampened ER-α36 expression. In conclusion, our findings not only indicate a new regulatory mechanism of let-7 miRNAs in ER mediated cellular malignant growth of breast cancer, and but also provide potential biomarkers and/or surrogate therapeutic targets useful for early diagnosis and/or therapeutic options for breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2025.
Abstract 2026: MicroRNA-214 is a negative regulator of p53
Authors: Yang Hua , Kong William , Williams Kendra , He Lili , Cheng Jin Q.
Published: February 2011

The p53 transcription factor mediates multiple cellular functions including the response to genotoxic stress, differentiation, cell cycle and apoptosis. Since p53 inactivation is a critical event in tumor development, the regulation of p53 and its pathway is of prime importance in the understanding of tumorigenesis. While a number of microRNAs have been shown to be regulated by p53, microRNA regulation of p53 is still not well documented. Here we demonstrate that miR-214, a putative oncogenic miRNA, regulates p53 protein but not mRNA level by direct targeting 3′UTR of p53. Ectopic expression of miR-214 represses p53 and enhances the resistance to radiation- or chemotherapeutic agent-induced cell cycle arrest and apoptosis in wild-type but not mutated p53 cells. Introduction of p53 cDNA lacking 3′UTR largely abrogates miR-214-induced cell growth and survival. Depletion of endogenous miR-214 elevates protein level of p53 and induces apoptosis in human cancer cell lines expressing wild-type p53. These findings indicate that miR-214 is an important posttranscriptional regulator of p53 and exerts its oncogenic activity through targeting p53.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2026.
Abstract 2032: MicroRNA control of tumor cell plasticity in a new tumor metastasis model
Authors: Banyard Jacqueline , Wilson Arianne M. , Bielenberg Diane R. , Zetter Bruce R.
Published: February 2011

We have developed a new prostate cancer model to discover the molecular changes underlying metastasis. A series of cell lines were developed by isolating metastatic cells from lymph nodes of nude mice following orthotopic injection of DU145 human prostate cancer cells and expression changes analyzed using gene chips. We found that these DU145-LN cells exhibit a mesenchymal-epithelial transition (MET). Repeated rounds of in vivo metastatic selection progressively increased the expression of epithelial markers including E-cadherin, cytokeratin-18 and EpCAM, and decreased mesenchymal markers such as vimentin. Despite being more epithelial, DU145-LN cells are more migratory and show reduced proliferation in vitro. However, they show increased tumorigenesis when reinjected into nude mice. Interestingly, clinical metastases are frequently epithelial, despite strong evidence that EMT enhances metastasis. To explain this, current models of metastasis invoke EMT with subsequent MET at the secondary site. Our cells appear to demonstrate this plasticity making them an ideal model system for studying MET regulation.

The MET changes in the DU145-LN cells suggested a coordinated mechanism of regulation. MicroRNA arrays revealed several candidates which correlated with the epithelial phenotype. DU145-LN cells showed increased expression of the miR-200 family (a, b, c and miR-141), and treatment with synthetic miR-200 inhibitors resulted in reduced cell-cell interactions and decreased E-cadherin levels. Our data complement recent evidence showing down-regulation of miR-200 by EMT. miR-200 acts in a feedback loop with the transcription factor ZEB1 to regulate EMT. We also observed significantly reduced expression of an additional microRNA not previously linked to cell morphology in the DU145-LN cells. Transfection of precursor miRNA to this target altered the epithelial morphology and reduced E-cadherin levels, suggesting an additional pathway of MET/EMT control. We are currently determining the mechanism of action of this new microRNA target.

Our data support a role for MET in tumor metastasis, and indicate that microRNAs are an important mechanism mediating tumor cell plasticity and EMT/MET.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2032.
Abstract 2035: The levels of miR-145 are regulated by DNA methylation and p53 gene status in prostate cancer
Authors: Suh Seong O , Zaman Mohd Saif , Shahryari Varahram , Chen Yi , Liu Jan , Tabatabai Z. Laura , Kakar Sanjay , Deng Guoren , Dahiya Rajvir
Published: February 2011

MiR-145 is down-regulated in various cancers. However, the regulation of miR-145 and its role in the prostate cancer is not known. We analyzed the expression of miR-145 in microdissected prostate cancers and adjacent normal prostate tissues. In 17 of 21 (81%) prostate cancers, the levels of miR-145 (measured by qRT-PCR) were significantly lower than those in the adjacent normal tissues. Down-regulated miR-145 levels correlated with DNA methylation (identified by methylation-specific PCR and sequencing) in the upstream region of miR-145, indicating that methylation may be involved in its regulation. The levels of miR-145 were also measured in 49 cancer cell lines, including 4 prostate cancer, 3 kidney cancer, 11 breast cancer, 23 colorectal cancer and 8 pancreatic cancer cell lines. In cancer cell lines, the down-regulation of miR-145 was also significantly correlated with its methylation. In seven cancer cell lines (3 prostate cancer, 2 kidney cancer and 2 colorectal cancer cell lines) with methylated miR-145, treatment with the demethylation agent, 5-aza-deoxycytidine significantly induced miR-145 expression. We also found a significant correlation between miR-145 expression and the status of the p53 gene in 49 cancer cell lines. In 31 cell lines with a p53 gene mutation, miR-145 levels were low in 30 cell lines (97%) while in 18 cell lines with wild type p53, miR-145 levels were low in only 6 cell lines (33%, p<0.001). There is a potential p53 protein binding site upstream of miR-145 flanked by methylated CpG sites. The binding ability of wild type and mutant p53 to this site with or without methylation, and the effects on the expression of miR-145 were tested by electrophoretic mobility shift assay (EMSA) and luciferase assay. In summary, this is the first report on miR-145 regulation by p53 mutation and DNA hypermathylation in prostate cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2035.
Abstract 2038: miR-149* induces apoptosis by inhibiting Akt1 and E2F1 in human cancer cells
Authors: Lin Ruey-Jen , Lin You-Chin , Yu Alice L.
Published: February 2011

microRNAs (miRNAs) play vital roles in several biological processes, including apoptosis, by negatively regulating the expression of target genes. The molecular mechanisms of the key survival signal, Akt family, have been extensively investigated, but whether is regulated by miRNA remains unknown. In a recent study of neuroblastoma samples, we found the expression of miR-149 to be lower in the high-risk group than the low- and intermediate-risk groups. Upon transfection of Be2C, a neuroblastoma cell line and HeLa cells with miR-149 oligo, no changes in cell growth were observed. On the other hand, ectopic expression of miR-149*, the cognate miRNA of miR-149, inhibited the growth and induced apoptosis in these two cancer cell lines. By TargetScan screening, Akt1, the predominant Akt isoform in most tissue, E2F1, and b-Myb were predicted as possible target genes of miR-149*. In Be2C and HeLa cells transfected with miR-149* oligo, reduced expressions of Akt1, E2F1, and b-Myb at protein level were detected by Western blotting, and decreased mRNA levels of Akt1 and E2F1 were also noted by RT-qPCR. Using luciferase reporter assay, the target sites were verified in the 3′UTRs of Akt1 and E2F1, but not in b-Myb, suggesting that Akt1 and E2F1 were the direct target and b-Myb was an indirect target of miR-149*. Silencing of Akt1 or E2F1 expression also led to similar apoptotic changes as miR-149* transfection in these two cell lines, suggesting that the pro-apoptotic effects of miR-149* was exerted at least in part by repressing Akt1 and E2F1 expressions. Importantly, analysis of primary neuroblastoma samples (n=56) revealed a significant inverse correlation of miR-149* with E2F1 expressions (p=0.026). Furthermore in stage1 samples, the mean expression level of miR-149* was significantly higher than in stage 2/3 (p<0.05), and that of E2F1 appeared to be lower. The results provide further support of an important role of miiR-149* in regulation of E2F1, especially in stage1 neuroblastoma tumors. Interestingly, using the reporter assays, excess miR-149 introduced by transfection to simulated its preponderance in the in vivo condition, could not overcome the repressive function of miR-149* on the target genes. This implies that the pro-apoptotic function of miR-149* may not be dampened by its predominant cognate, miR-149, in vivo. Our findings not only provided the first evidence that Akt1 is a direct target of a miRNA but also demonstrated that miR-149* is a pro-apoptotic miRNA by repressing the expression of Akt1 and E2F1.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2038.
Abstract 2044: Altered microRNA expression induced by tumorigenic conazoles in mouse liver
Authors: Ross Jeffrey A. , Blackman Carl F. , Thai Sheau-Fung , Li Zhiquan , Kohan Michael , Jones Carlton P. , Chen Tao
Published: February 2011

Triadimefon, propiconazole, and myclobutanil are conazoles, an important class of agricultural and therapeutic fungicides. Triadimefon and propiconazole are mouse liver tumorigens, while myclobutanil is not. As part of a coordinated study to understand the molecular determinants of conazole tumorigenicity, we analyzed the microRNA expression levels in control and conazole treated mice after 90 days of administration in feed. Groups of mice were fed either control diet or diet containing 1800 p.p.m. triadimefon, 2500 p.p.m. propiconazole or 2000 p.p.m. myclobutanil. MicroRNA was isolated from livers and analyzed using Superarray whole mouse genome miRNA PCR arrays from SABioscience. Data were analyzed using the Significance Analysis of Microarrays (SAM) procedure. We identified those miRNAs whose expression was either increased or decreased relative to untreated controls with q ≤ 0.01. The tumorigenic conazoles induced many more changes in miRNA expression than the non-tumorigenic conazole. A group of 19 miRNAs was identified whose expression was significantly altered in both triadimefon and propiconazole treated animals but not in myclobutanil treated animals. All but one of the altered miRNAs were downregulated compared to controls. The greatest fold-changes in miRNA expression were observed for mmu-mir-135b and mmu-mir-684. Among the putative targets of the miRNAs altered by tumorigenic conazoles are genes involved in regulation of apoptosis and cell proliferation. This abstract does not reflect US EPA policy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2044.
Abstract 2049: Post transcriptional regulation of RhoB expression
Authors: Glorian Valerie , Maillot Gerard , Poles Sophie , Favre Gilles , Vagner Stephan
Published: February 2011

Rho GTPases contribute to most steps of cancer initiation and progression, including the acquisition of unlimited proliferation potential, survival, tissue invasion and the establishment of metastases. By contrast to RhoA and RhoC, RhoB has been proposed to act as a tumor suppressor as it is activated in response to various stresses including UV exposure, and since it has been reported to inhibit tumor growth, cell migration and invasion. Unlike RhoA and RhoC, RhoB is often down regulated in human tumour tissues including lung and head and neck cancer and its expression is inversely correlated with tumor aggressiveness. However, the epigenetic regulation of RhoB expression in cancer cells remains to be elucidated. Since several recent works demonstrate that post-transcriptional deregulation of gene expression is involved in carcinogenesis, we have investigated the post-transcriptional regulation of RhoB expression. The RhoB 3’ untranslated region is well conserved between species and has numerous putative binding sites for post-transcriptional regulators such as mRNA binding proteins and microRNAs. By using luciferase assays and polysome analysis, we have found that the translation of the RhoB mRNA is regulated upon UV exposure. One specific miRNA, miR-19b whose expression is regulated by UV, directly targets the RhoB mRNA to control RhoB expression and UV-induced apoptosis. Interestingly, other post-transcriptionnal regulators involved in RhoB expression, such as the mRNA binding proteins HuR and TiaR were also indentified by functional assays using RNA interference strategy. Immunohistochemical analysis on a cohort of human lung tissues ranging from normal to invasive carcinoma are underway to detect a possible correlation between the expression of these proteins and RhoB downregulation in tumor.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2049.
Abstract 205: Bortezomib and paclitaxel synergistically induce apoptosis in chronic myelogenous leukemia cells
Authors: Bucur Octavian , Stancu Andreea L. , Petrescu Stefana M. , Khosravi-Far Roya
Published: February 2011

Bcr-Abl fusion protein plays a critical role in the pathogenesis and progression of Chronic Myelogenous Leukemia (CML) and in some of the Acute Lymphocytic Leukemia (ALL) cases. Current inhibitors of Abl kinases, such as Imatinib, have shown great promise in the treatment of CML, however, the emergence of the resistance and the persistence of the residual disease have underlined the importance of finding new ways of treatment CML and especially of the resistant forms of CML. We and others have previously shown that Bortezomib (FDA approved for the treatment of Multiple Myeloma), a selective proteasome inhibitor, efficiently induces apoptosis in Imatinib resistant Bcr-Abl T315I cells, and established Bortezomib as a potential important treatment in Bcr-Abl positive leukemias, determining the initiation of at least five different clinical trials for the treatment of CML, alone or in combination.

We are further showing here that Bortezomib in combination with the mitotic inhibitor Paclitaxel act synergistically in inducing apoptosis in Bcr-Abl positive cells. Paclitaxel, a mitotic inhibitor drug (FDA approved drug for the treatment of lung, ovarian, breast, head and neck cancers, and advanced forms of Kaposi's sarcoma) is also now in clinical trials for the treatment of CML. However, to our knowledge, there are no clinical trials or other studies regarding the combined treatment of Bortezomib and Paclitaxel in Bcr-Abl positive CML.

RESULTS: Combined treatment of Bortezomib and Paclitaxel synergistically induces cell death in human Bcr-Abl positive K562 cell line, by activating the initiator caspase 9 and effector caspase 3, which leads to the cleavage of a number of substrates, such as Poly ADP Ribose Polymerase (PARP), and results in apoptosis. Additionally, the exposure of the Bcr-Abl positive leukemia cells to the Bortezomib/Paclitaxel regimen results in an increase in the activation of the stress-related MAP kinases (such as p38 MAPK and JNK) versus the cytoprotective kinases (ERK1, ERK2), suggesting a possible implication of JNK and p38 MAPK in mediating the effect of the combined treatment. Moreover, we also show that the combined treatment is effective in inducing apoptosis in the murine Baf3 Bcr-Abl and Imatinib resistant Baf3 Bcr-Abl T315I cell lines, suggesting a potential use of the regimen in Imatinib resistant forms of CML.

CONCLUSION: Taken together, these findings underline that the combined treatment with Bortezomib and Paclitaxel represents a potentially promising strategy for the treatment of Chronic Myelogenous Leukemia in general, and of Imatinib resistant CML in particular.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 205.
Abstract 2050: MicroRNA-124a: A master regulator of glioblastoma migration
Authors: McDonald Kerrie L. , Fowler Adam , Thomson Daniel , Giles Keith , Leedman Peter , Robinson Bruce G.
Published: February 2011

For most patients diagnosed with a glioblastoma multiforme (GBM), the invasiveness of this tumor and its resistance to treatment predicts a poor outcome with no realistic possibility of a cure. Although brain tumor cells rarely metastasize outside the brain, they have an extraordinary capacity to migrate long distances and infiltrate normal brain, making complete surgical removal impossible. New therapeutic strategies are needed to target the invading cell population to further reduce tumor cell spread and a better understanding of the mechanisms promoting tumor migration and invasion are urgently needed.

MiR-124a, a microRNA, normally abundantly expressed in normal adult brain tissue, shows marked down regulation (>1000 fold) in GBM cell lines (A172, T98G, MO59J, MO59K and U87MG). Conversely, a predicted miR-124a target, IQGAP1, is over-expressed in GBM cell lines and tissue samples. We previously demonstrated IQGAP1 overexpression in 86% of GBM patients and associated high levels with poor prognosis. IQGAP1 expression was prominent in the actively migrating and rapidly dividing palisading neoplastic cells that surround the necrotic foci.

We hypothesized a reciprocal interaction between miR-124a and IQGAP1. To show this, GBM cell lines were transfected with a synthetic miR-124a precursor molecule to increase endogenous miR-124a expression. Cell migration was measured by impedence of a current (ECIS 9600) and tumor cell invasion was measured using transwell inserts. The interaction between miR-124a and IQGAP1 was ascertained using quantitative PCR, Western Blot analysis and luciferase reporter assays.

Transfected miR-124a-GBM cells did not show any alterations in cell proliferation however significant reductions in tumor cell migration and invasion were observed when compared to control cells. Reducedmigration and invasion was also observed when GBM cells were transiently transfected with siRNA directed at IQGAP1. A direct effect of miR-124a on IQGAP1 expression levels was demonstrated at the mRNA and protein levels via miR-124a targeting the IQGAP1 mRNA 3’-UTR.

In summary, we show that miR-124 functions as a tumour suppressor miRNA being downregulated in GBM which results in overexpression of IQGAP1. Additional migratory proteins commonly overexpressed in GBM also possess predicted miR-124a target sites and are currently been evaluated. miR-124a may therefore act as a master regulator of GBM invasiveness. Furthermore, delivery of miR-124a into GBMs may represent as a novel therapeutic approach to limit GBM invasion both alone and in combination with convential chemotherapy treatments.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2050.
Abstract 2051: DNA (cytosine-5-)-methyltransferases 3A (DNMT3A) is a direct target of miR-194 in breast cancer
Authors: Le Xiao-Feng , Spizzo Riccardo , Mao Maggie , Wu Yun , Calin George A. , Bast Robert C.
Published: February 2011

microRNAs (miRNAs) are small non-coding RNAs of 19-25 nucleotides in length that can modulate gene expression that regulate biological and malignant processes. DNA methylation is catalyzed primarily by three DNMTs - DNMT1, DNMT3A, and DNMT3B and contributes to cancer initiation and progression. While DNMT3A protein overexpression has been detected in colon, lung, skin and testis cancers, its expression in breast cancer has not been previously reported. Targets and function for miR-194 have not been well defined. In this study, we investigated the expression of miR-194, DNMT3A, and the possible role of miR-194 in regulating DNMT3A in breast cancer cells. Expression of miR-194 precursor in breast cancer cell lines specifically downregulated DNMT3A mRNA and protein levels. miR-194 specifically inhibited the luciferase activity of wild type DNMT3A 3’-UTR construct, but not that of mutant vector, indicating that DNMT3A is a direct downstream target of miR-194. Furthermore, miR-194 expression appeared to correlate inversely with DNMT3A mRNA or protein expression in breast cancer cell lines and patient samples. An increase in miR-194 expression stimulated tumor suppressors cyclin G2, p27Kip1 and ADAM23 expression, which can be regulated by DNA methylation. Overexpression of miR-194 inhibited cell motility of breast cancer cells without alteration of the cell cycle distribution. Most DNMT3A protein localized in the nucleus, but a small fraction of DNMT3A protein was found in the cytoplasm. The prognostic value of miR-194 and DNMT3A in breast cancer is being studied using a breast cancer tissue array, quantitative real time PCR and immunohistochemical staining. In summary, this report demonstrates DNMT3A as a direct target of miR-194 in breast cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2051.
Abstract 2052: MicroRNA-101 promotes apoptosis and suppresses proliferation in esophageal squamous cell carcinoma by repressing the polycomb group protein EZH2
Authors: Hiyoshi Yukiharu , Kamohara Hidenobu , Kurashige Junji , Kinoshita Kouichi , Hayashi Naoko , Watanabe Masayuki , Baba Hideo
Published: February 2011

Background: MicroRNAs (miRNAs) are ∼22 nucleotide non-coding RNA molecules that regulate gene expression post-transcriptionally. Although aberrant expression of miRNAs has been observed in various types of human cancer, their pathophysiologic role and their relevance to tumorigenesis are still largely unknown. Overexpression of the enhancer of zeste homolog 2 (EZH2) protein, a known repressor of gene transcription, has been reported to be associated with biological malignancy in several types of cancer.

Purpose: The aim of this study was (1) to analyze the expression and function of microRNA-101 (miR-101) in esophageal squamous cell carcinoma (ESCC), (2) to elucidate the regulation of the EZH2 expression by miR-101 as its target gene.

Methods: miR-101 expression was investigated in 27 matched normal esophageal epitheliums and ESCCs and 12 ESCC cell lines (TE1, 4, 6, 8, 9, 10, 11, 12, 13, 14, 15, KYSE30) by TaqMan quantitative real-time-polymerase chain reaction (qRT-PCR). To evaluate the role of miR-101, cell proliferation and apoptosis was analyzed with pre-miR-101-precursor transfected cells. Next, the regulation of EZH2 by miR-101 was analyzed by real-time PCR and western blotting. In addition, to elucidate the role of EZH2 gene in ESCC, we immunohistochemically examined the expression of EZH2 protein in 120 resected ESCC specimens and determined its association with the clinicopathological characteristics and prognosis.

Results: In matched 27 resected specimens, the expression of miR-101 was significantly down-regulated in ESCCs compared with normal epitheliums. All 15 ESCC cell lines also showed down-regulation of miR-101. Pre-miR-101-precursor transfected cells promote cellular apoptosis and showed significant reduction in cellular proliferation. Pre-miR-101-precursor transfected cells significantly repressed EZH2 expression in both mRNA level and protein level. In the immunohistochemical analysis of EZH2, 78 (65%) showed positive staining, while 42 (35%) lacked the staining. Positive staining for EZH2 was associated with a poor prognosis significantly. Conclusions: miR-101 promotes apoptosis and suppresses proliferation in ESCC by repressing EZH2 expression as a tumor-suppressive-microRNA. It plays an important role in progression of ESCC and may serve as a novel therapeutic target.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2052.
Abstract 2053: Regulation of microRNA-10b by CCN5/WISP-2 in breast cancer: A novel mechanism of CCN5/WISP-2 mediated suppression of invasive front
Authors: Haque Inamul , Banerjee Snigdha , Mehta Smita , Phillips Teresa A. , Dhar Gopal , Kambhampati Suman , Banerjee Sushanta K.
Published: February 2011

Metastatic cells are a subset of primary tumor cells that have the skill to complete multi-step metastatic cascades, including dissemination, migration, extravasation, and eventual proliferation) at a discontinuous secondary site. Understanding the molecular biology of cancer metastasis may provide novel intervention strategies to control metastatic lesions, and/or to improve the quality of life for the patients with these advanced diseases. MicoRNAs are naturally occurring single-stranded RNA molecules that posttranscriptionally regulate the expression of target mRNA transcripts. Many of these target mRNA transcripts are involved in cell proliferation, differentiation and apoptosis, processes commonly altered during tumorigenesis. Recent findings have shown that microRNA-10b (miR-10b) is highly expressed in metastatic breast cancer cells and positively regulates cell migration and invasion. Expression of miR-10b is induced by Twist, a transcription factor that binds to putative promoter of miR-10b. We hypothesized that whether nullification of CCN5/WISP-2, an antiinvasive gene has any role in miR-10b expression. We found that nullification of CCN5/WISP-2 in ER-positive noninvasive breast tumor cell upregulates the miR-10b expression. Interestingly, we also found the upregulation of Twist by silencing CCN5/WISP-2. Collectively, we conclude that CCN5/WISP-2 may be a critical regulator of miR-10b expression through the HIF-1α-Twist signaling.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2053.