bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 4081: Antisense against U6 induces cytotoxicity in cancer cells
Authors: Lin Xiaoqin , Hwang Larn , Desai Neil , Trieu Vuong 
Published: February 2011

Abstract
Background: The U6 snRNA is one of the most conformationally dynamic RNAs in the spliceosome. In preparation for spliceosome assembly, the U6 3′ intramolecular stem-loop unwinds and the exposed sequences pair with U4 RNA to form the U4/U6 small nuclear ribonucleoprotein complex. After assembly of the spliceosome on an intron, spliceosome activation occurs, during which U4 RNA is unwound from U6 RNA. U6 then base-pairs with U2 RNA to form the catalytically active form of the spliceosome. Upon activation of the spliceosome the “U6-ISL” structure forms to position important nucleotides of the U6 snRNA at the 5′splice site so they can base-pair with the pre-mRNA at the 5′ prime splice site. Here we report the cytotoxic activity against cancer cells treated with antisense DNAs against U6, especially those targeting U6-ISL.
Methods: The functional activity of U6 antisense oligos was tested by cytotoxic and apoptosis assays. In the cytotoxic assay, U6 antisense oligos were reverse transfected into various mammalian cell lines, and the cytotoxic activity was measured by cell-titer blue 72 hr post-transfection. In the apoptosis assay, U6 antisense oligos are reverse transfected into various mammalian cell lines, and the apoptosis was measured by the release of caspase 3/7 72 hr post-transfection. To evaluate the knockdown ability of antisense oligos, the expression level of U6 snRNA was measured by Taqman Gene Expression Assay. The localization of U6 antisense oligos in tissue assay was studied by ISH. The effects of U6 antisense oligos on cellular protein and mRNA profile were also examined using microarray technology.
Results: About 100 U6 antisense oligos were synthesized. Several U6 antisense oligos were identified to significantly induce cytotoxic activity of HT29 and other cancer cell lines but not in normal cells, such as hepatocytes. No significant apoptosis activity was induced by any U6 antisense oligos. The identified U6 antisense oligos localized at the nucleus and knocked down the U6 snRNA in vitro, suggesting that U6 antisense oligos target to U6 snRNA and lead to the downregulation of U6 snRNA. mRNA microarray and antibody array showed that U6 oligos regulate various mRNA and protein expression in cancer cells. The most effective U6 antisense oligos were those targeting the U6-ISL.
Conclusions: Antisense against U6, especially those targeting U6-ISL region, were effective in U6 knockdown and cytoxicity against cancer cells in vitro.
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 4081.
Abstract 4084: Alteration of BC200 RNA biogenesis in cancer cells
Authors: Lee Jungmin , Kim Youngmi , Kim Minseok S. , Lee Younghoon 
Published: February 2011

Abstract
BC200 RNA was initially identified as a noncoding RNA of about 200 nt in somatodendritic domains of human nerve cells. It is thought to act as a translational modulator for local protein synthesis. Since BC200 RNA was not observed in somatic cells other than neurons, it was regarded as a neural-specific RNA. However, the neuron-only expression of BC200 does not hold true because it is highly expressed in a number of tumors that are of non-neuronal origin. In this study, we examined biogenesis of BC200 RNA in tumors in detail using cancer cell lines. BC200 RNA was expressed at high levels in several cancer cell lines, but at low levels in normal cell lines. Primer extension analysis and self-ligation RACE revealed that the size of BC200 RNA isolated from cancer cells was heterogeneous, implying the difference of BC200 RNA biogenesis between cancer cells and neural cells. The treatment of actinomycin D, a transcription inhibitor, had little effect on the cellular level of BC200 RNA in cancer cells, but led to the rapid degradation of BC200 RNA in normal cells. This result suggests that BC200 RNA is metabolically unstable in normal cells, while it becomes stable in cancer cells. The increase of stability of BC200 RNA in cancer cells could explain why BC200 RNA was observed at high levels in cancer cells. For cancer cells to maintain high levels of BC200 RNA, therefore, they should have a strategy for RNA protection that normal cells cannot provide. If BC200 RNA plays analogous functional roles in cancer cells as in nerve cells, BC200 RNA may provoke tumorigenesis by repressing translation of tumor suppressing genes.
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 4084.
Abstract 4090: RASSF1A gene specific methylation by overexpression of miR-200c in lung cancer
Authors: Chun Sung-Min , Jin Min-Young , Choi Jene , Lee Je-Hwan , Hwang Jung Jin , Kim Chung-Soo , Jang Se Jin 
Published: February 2011

Abstract
DNA methylation, which is an important epigenetic mechanism of gene regulation during cellular differentiation, is mediated by enzymatic actions of DNA methyl transferase family (DNMT). In pathologic conditions, however, certain critical genes such as tumor suppressor genes of various human cancers are aberrantly methylated resulting in inactivation of the genes regardless of DNMT amount. In this process, what induces aberrant methylation of a specific gene is currently unknown. We focused actions of microRNA because of their natural function of sequence recognition. As a model, we selected miR-200c and RASSF1A since those are frequently overexpressed and hypermethylated in lung cancer, respectively, and have partial sequence homology between miR-200c and promoter region of RASSF1A. In this study, we tested expression of miR-17, 21, 200c and 205 by quantitative real-time PCR and methylation status of RASSF1A, CDH13, p16ink4a, DAPK1, and APC1 by pyrosequencing assay in 3 lung cancer cell lines and 10 fresh frozen normal and tumor lung tissues. Fluorescent In Situ Hybridization (FISH) using anti-miR-200c probe labeled with Cy-3 dye was performed to confirm expression and localization of mature miR-200c. Interestingly, we found A549 and H460 cells were completely hypermethylated in RASSF1A promoter region and showed high level of miR-200c expression. In contrast, Calu6 cells showed opposite results. In vitro inhibition of miR-200c by transfection of anti-miR-200c oligonucleotide induced gradual decrease in methylation level of RASSF1A in A549 and H460 cells without change in expression of DNMT. Decrease of CpG methylation by anti-miR-200c transfection was associated with increase of RASSF1A gene expression in A549 and H460 cells. Calu6 cell showed no change in methylation level of RASSF1A. This effect was not seen in anti-miR-17 transfected cells. Transfection of anti-miR-200c did not affect methylation level of other frequently hypermethylated genes including CDH13, p16ink4a, DAPK1, and APC1. The results suggest that overexpression of miR-200c induces sequence specific methylation of RASSF1A and provide a clue to gene specific reactivation of epigenetically silenced genes. (This work was supported by the Korea Research Foundation Grant funded by the Korean Government. [KRF-2008-357-E00006], This study was supported by a grant of the Korea Health 21 R&D Project, Ministry of Health & Welfare, Republic of Korea. (A062254))
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 4090.
Abstract 4092: Aberrant miRNA methylation in tumors from surgically resected lung cancer patients and association with survival
Authors: Tan Weiqi , Gu Jian , Hildebrandt Michelle , Huang Maosheng , Wistuba Ignacio I. , Roth Jack A. , Spitz Margaret R. , Wu Xifeng 
Published: February 2011

Abstract
MicroRNAs (miRNAs) are small non coding RNAs of about 22 nucleotides in length, which regulate their target gene expression by binding to the 3′ UTR of mRNA. Recent studies have shown that some miRNAs are regulated by DNA methylation and aberrant miRNA gene methylation contributes to human tumorigenesis. In this study, we used real-time quantitative methylation-specific PCR to detect a panel of miRNA methylation in tumor and adjacent normal tissues from surgically resected lung cancer patients. We found significantly higher methylation levels of miR-124a family, miR-126, miR-193a, miR-9 family, and miR-34b/c in tumor tissues (N=107) than in normal tissues (N=19, P&lt;0.05), but no significant difference was found for miRNA-137 and miRNA-148a. The methylation levels of four miRNAs (miRNA-124a3, miRNA-148a, miR-9-3, and miR-34b/c) were higher in tumors from older patients than those from younger patients. MiR-9-1 (29.56±29.51) and miR-9-3 (30.49±28.50) had higher methylation in tumors from current smokers than never smokers (15.77±15.28 and 10.71±11.32, P=0.036 and 0.021, respectively). There were no significant differences in methylation levels of these four miRNAs between tumors from men and women. Hypermethylation of miR-9-1, miR-9-3, miR-34b/c and miR-148a was associated with significantly better survival with hazard rations of 0.35 (95% CI, 0.17-0.72), 0.48 (95% CI, 0.25-0.91), 0.52 (95% CI, 0.27-0.99), and 0.52 (95% CI, 0.28-0.98), respectively. Our results demonstrated that selected miRNAs are hypermethylated in lung cancer and miRNA hypermethylation might be a useful biomarker in detection and prognosis of lung 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 4092.
Abstract 4093: miR-193b is an epigenetically regulated putative tumor suppressor in prostate cancer
Authors: Rauhala Hanna E. , Jalava Sanni E. , Isotalo Jarkko , Bracken Hazel , Lehmusvaara Saara , Oja Hannu , Tammela Teuvo L. , Visakorpi Tapio 
Published: February 2011

Abstract
miRNAs have proven to be key regulators of gene expression and are differentially expressed in various diseases, including cancer. Our aim was to identify epigenetically dysregulated genes in prostate cancer. We performed miRNA expression profiling after relieving epigenetic modifications in six prostate cancer cell lines and non-malignant prostate epithelial cells. 38 miRNAs showed increased expression in any prostate cancer cell line after 5-aza-2′-deoxycytidine (5azadC) and trichostatin A (TSA) treatments. Six of these also had decreased expression in clinical prostate cancer samples compared to benign prostatic hyperplasia. Among these, miR-193b was methylated in 22Rv1 cell line at a CpG island ∼1kb upstream of the miRNA locus. Expressing miR-193b in 22Rv1 cells using pre-miR-193b oligonucleotides caused a significant growth reduction (p&lt;0.001) resulting from a decrease of cells in S-phase of the cell cycle (p&lt;0.01). In addition, the anchorage independent growth was partially inhibited in transiently miR-193b -expressing 22Rv1 cells (p&lt;0.01). Altogether, our data suggest that miR-193b is an epigenetically silenced putative tumor suppressor 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 4093.
Abstract 4094: Pancreatic cancers epigenetically silence ZFHX1B, hypomethylate and overexpress miR-200a/−200b, in association with elevated circulating miR-200a and miR-200b levels
Authors: Li Ang , Omura Noriyuki , Hong Seung-Mo , Vincent Audrey , Walter Kimberly , Griffith Margaret , Borges Michael , Goggins Michael 
Published: February 2011

Abstract
Aberrant DNA methylation and miRNA expression play important roles in the pathogenesis of pancreatic cancer. While interrogating differentially methylated CpG islands in pancreatic cancer we identified two members of miR-200 family, miR-200a and miR-200b that were hypomethylated and overexpressed in pancreatic cancer. We also identified prevalent hypermethylation and silencing of one of their downstream targets, ZFHX1B (SIP1, ZEB2), whose protein product suppresses E-cadherin expression and contributes to epithelial mesenchymal transition. In a panel of 23 pancreatic cell lines we observed a reciprocal correlation between miR-200, ZFHX1B and E-cadherin expression with pancreatic cancer associated fibroblasts showing the opposite expression pattern to most pancreatic cancers. In Panc-1cells, which express ZFHX1B, have low E-cadherin expression and do not express miR-200a or miR-200b, exogenous expression of miR-200a and miR-200b down regulated ZFHX1B mRNA and increased E-cadherin expression. However, most pancreatic cancers express miR-200a and miR-200b, but this expression does not affect ZFHX1B expression as the ZFHX1B promoter is silenced by hypermethylation, and in these cancers E-cadherin is generally expressed at or above normal levels. Both miR-200a and miR-200b were significantly elevated in the sera of pancreatic cancer and chronic pancreatitis patients compared to healthy controls (p&lt;0.0001), yielding receiver operating characteristic curve areas of 0.861 and 0.85, respectively. In conclusion, most pancreatic cancers display hypomethylation and overexpression of miR-200a and miR-200b, silencing of ZFHX1B by promoter methylation and retain expression of E-cadherin. The elevated serum levels of miR-200a and miR-200b in most patients with pancreatic cancer could have diagnostic utility.
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 4094.
Abstract 4097: Protein tyrosine phosphatase SHP-2 regulates human pancreatic cancer cell biology on collagen I
Authors: Connelly Sarah , Isley Beth A. , Baker Cheryl H. , Summy Justin M. 
Published: February 2011

Abstract
With a five year survival rate of less than 5%, pancreatic cancer stands as one of the deadliest human malignancies. There is a great need for novel therapeutic strategies for this illness, and improving our understanding of pancreatic cancer biology will be a key step in developing these therapies. The purpose of these studies is to investigate the regulation and function of the Src Homology 2 (SH2) domain containing protein tyrosine phosphatase SHP-2 in human pancreatic cancer cells and to determine its potential value as a therapeutic target for this disease. In other cellular systems, SHP-2 is crucial for integrin and receptor tyrosine kinase-mediated activation of diverse signaling pathways, regulating many of the cellular events necessary for oncogenesis, including cell division, motility, adhesion, and survival. We hypothesized that inhibition of SHP-2 function would negatively impact integrin-mediated cell signaling and biology in response to the extracellular matrix protein collagen I, an abundant component of pancreatic tumor stroma in vivo. Initial results demonstrate that SHP-2 expression and tyrosine phosphorylation/activity are elevated in pancreatic cancer cells, relative to immortalized normal human pancreatic cells. Phosphorylation of SHP-2 is further elevated in the presence of collagen I. SHP-2 tyrosine phosphorylation in pancreatic cancer cells occurrs in a Src family kinase-dependent fashion. Initial results using miRNA-mediated knock-down of SHP-2 expression indicate the importance of SHP-2 for the ability of pancreatic cancer cells to proliferate, migrate and heal cell culture wounds on collagen I. Additionally, SHP-2 knockdown cells grown on collagen I demonstate altered tyrosine phosphorylation patterns of several signal transduction proteins, including focal adhesion kinase (FAK), in comparison to controls. These data suggest, for the first time, an importance for SHP-2 in pancreatic cancer cell biology and the potential value of SHP-2 as a therapeutic target for this disease. Ongoing and future experiments will compare the effects of SHP-2 inhibition on pancreatic tumor growth in vivo.
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 4097.
Abstract 4105: Nitric-oxide-mediated inhibition of Na+/H+ exchange (NHE) is a novel mechanism of bile acid induced damage: Relevance to esophageal carcinogenesis
Authors: Goldman Aaron , Shahidullah Mohammad , Chen Hwudaurw , Delamere Nicholas , Dvorak Katerina 
Published: February 2011

Abstract
Background: Barrett's esophagus (BE) is a premalignant condition that is associated with gastroesophageal reflux disease (GERD). Gastric acid and bile acids are two components of refluxate that induce proliferation, DNA damage and oxidative stress. In combination, the effects of gastric acid and bile acids are amplified and synergistic. The major goal of this study was to evaluate the effect of bile acids alone or in combination with acid on intracellular pH (pHi). A mechanism responsible for bile acid-induced pHi alterations was examined.
Methods: CP-A cells (non-dysplastic Barrett's esophagus cells) were treated with medium acidified to pH 5.5 and/or 0.5mM bile acid cocktail in the presence/absence of inhibitors of nitric oxide synthase (NOS) or NHE (sodium-hydrogen exchanger). pHi was measured by BCECF microfluorimetry in perfused cells, nitric oxide by DAF-FM fluorescence and DNA damage by the comet assay. Western blot analysis was used to detect the expression of phosphorylated (activated) eNOS, iNOS and NHE1.
Results: A dose-dependent decrease in pHi was observed in CP-A cells exposed to bile acids. Bile acid-induced intracellular acidification was abolished when NO production was inhibited by a nonspecific NOS inhibitor L-NAME or by thea specific iNOS inhibitor 1400W. In contrast the NHE inhibitor DMA, significantly decreased the bile acid-mediated pHi response. Exposure of the cells to acidified medium (pH5.5) containing a 0.5mM bile acid cocktail, markedly decreased pHi pHi to a value below extracellular pH. Importantly, medium acidified to pH5.5 containing 0.5mM bile acids induced a similar decrease in pHi as medium acidified to pH 4.5 without bile acids. This The same treatment resulteds in a 250% increase in acid-mediated DNA damage compared to medium acidified to pH5.5 in CP-A cells.
Conclusion: In summary, a new mechanism of bile acid induced damage was identified. Bile acids alone or in combination with acidic pH significantly decrease intracellular pH in esophageal cells. The results suggest the effect ofresponse tpo bile acids is the consequence of NOS activation and that leads to NHE inhibition. The mMarked increase in DNA damage after suggests exposure to bile acids in combination with acid may play a crucial role in esophageal 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 4105.
Abstract 4116: Relationship between K-ras 4A and superoxide in lung adenocarcinoma cell lines
Authors: Calvert Richard J. , Maciag Anna E. , Anderson Lucy M. 
Published: February 2011

Abstract
The K-ras gene is mutated in 30-50% of human lung adenocarcinomas, and even more frequently in cancers of colon and pancreas. It exists in two protein isoforms, K-ras 4A and 4B. Their amino acid sequence is very similar, except for marked differences in the hypervariable domain near the carboxyl terminus. K-ras 4B, with a polylysine tail, is unique among the ras gene products and is the dominant K-ras isoform in most tissues. Wild-type K-ras 4B has tumor suppressor activity (Zhang et al. Nature Gen. 29:25, 2001), whereas K-ras 4A was recently found to be necessary for lung tumor development in mice (To et al. Nature Gen. 40:1240, 2008). In search of an oncogenic function for K-ras 4A in lung cancer, we previously demonstrated a highly significant (P&lt;0.01) positive correlation between K-ras 4A expression, at both mRNA and protein levels, and superoxide amounts in a panel of 11 human lung adenocarcinoma cell lines (Proc. Am. Assoc. for Cancer Research 50: (#437)). Superoxide has been widely implicated in cancer causation and progression. In the present study, we test whether there is a cause-effect relationship between expression of K-ras 4A and superoxide production. Cell line H441 expresses high levels of both superoxide and K-ras 4A. Superoxide levels were determined using a nitroblue tetrazolium (NBT) assay and K-ras 4A protein levels quantified by immunoblot with a specific antibody. Results are means ± SEMs. The effect of reduced levels of K-ras 4A on superoxide production was determined using a K-ras 4A silencing siRNA, which reduced K-ras 4A protein by 60.2 ± 3.0% after 72 hours of siRNA treatment. This reduction had no effect on superoxide (control 1.13 ± 0.08, siRNA 1.17 ± 0.08 nmol NBT reduced/ug protein). The effect of reduced levels of superoxide on K-ras 4A expression was determined using 5 mM Tiron, an electron scavenger. A 36% decrease in superoxide did not affect K-ras 4A protein levels (control 26.90 ± 0.89 vs. Tiron-treated 26.89 ± 1.91, arbitrary units). If these preliminary results are confirmed with additional cell lines and reagents, they may suggest that both expression of K-ras 4A and production of superoxide are controlled by another, pro-oncogenic factor or set of conditions. In view of the importance of both K-ras and superoxide in cancer, discovery of this putative central pro-oncogenic regulator might offer an important preventive and therapeutic target in lung 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 4116.