bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract B44: Probing the effects of linker flexibility in second mitochondria-derived activator of caspases mimetic dimers and assessing their ability to induce apoptosis in a MDA-MB-231 cell line
Authors: Cheema Taz , Ben Robert , Cheung Herman , LaCasse Eric 
Published: June 2012

Abstract
Programmed cell death (apoptosis) is the most common mechanism of cell death in eukaryotes. The ability of cancer cells to evade and inhibit apoptosis has become a hallmark feature of cancer. This is accomplished through a family of proteins known as the inhibitor of apoptosis proteins (lAPs). X-linked inhibitor of apoptosis protein (XIAP) is one of the best characterized lAPs. XIAP suppresses apoptosis by forming complexes with cysteine-aspartic proteases (caspase), in particular caspase −3, −7, and −9 through one of its baculovirus IAP repeat (BIR) domains. Second mitochondria-derived activator of caspases (SMAC) is an antagonist protein released from the mitochondria and into the cytosol, to disrupt the complexes produced between XIAP and caspase. SMAC binds to the BIR domains in XIAP through its tetra-peptide motif, AVPI. Studies have demonstrated that the first and third amino acid positions of this tetra-peptide motif are important for binding, while positions two and four can be modified to increase binding affinity (AXPX).
It has also been shown that dimers of SMAC mimetics show greater potency than their monomer counter parts. Previously, our laboratory has synthesized and tested SMAC dimers using three glycine amino acids to link AXPX sequences. These compounds showed very little activity. We also synthesized and tested SMAC dimers comprised of a lysine amino acid, linking two AXPX sequences; these mimetics did display significant activity. In particular an (AKPF)2K sequence showed 50% cell death at 10 uM when combined with death ligand TRAIL. Synthesis of these compounds was conducted using solid phase peptide synthesis (SPPS) on a polystyrene resin.
We hypothesized that flexibility in the linker joining the two AXPX sequences was necessary to increase binding affinity. Consequently several SMAC mimetic dimers built on two different linkers (gamma-amino butyric acid and ornithine), both of which have a four carbon spacer between each terminus, have been prepared and evaluated for activity using a MDA-MB-231 breast cancer cell line. The first series of SMAC mimetic compounds consists of MeAXPX-GABA-MeAXPX amino acid sequence while the second series of SMAC mimetics are comprised of a MeAXPX-Ornithine-XPXMeA amino acid sequence. All data and results, including synthesis, biological assays, and the testing of these compounds will be the major focus of this presentation.
Citation Information: Clin Cancer Res 2010;16(14 Suppl):B44.
Abstract B45: The short-term effects of arsenic on Cdk5-dependent apoptosis of prostate cancer cells
Authors: Chen Mei-Chih , Wang Paulus S. , Lin Ho 
Published: June 2012

Abstract
Arsenic compounds have been used widely in medicine to treat a variety of diseases. However, it has also been believed to involve the carcinogenesis of prostate cancer and the hormone disruption might be one of the causes. Our previous results indicate that digoxin treatment leads to apoptosis of prostate cancer cells through Cdk5 overactivation, in which the regular activator of Cdk5, p35, is cleaved into more potent one, p25. Here, our latest data showed that arsenic also caused p35 cleavage and subsequently Cdk5 overactivation in prostate cancer cells. Similarly, this arsenic- induced stimulatory effect on Cdk5 resulted in apoptosis of prostate cancer cells accompanying with the degradation of androgen receptor in LNCaP cells. This result implies that androgen is no longer a trophic factor for prostate cancer cells after arsenic treatment. Although STAT3 was identified by us as a Cdk5 substrate responding to tumor growth, arsenic-triggered Cdk5 overactivation did not increase STAT3 phosphorylation. In conclusion, although long-term exposure of arsenic possibly causes prostate cancer, our present results provide evidence indicating that in vitro and short-term treatments of arsenic might lead to apoptosis of prostate cancer cell lines through Cdk5 overactivation pathway. This study may arouse the new indication for the old chemical and also shed light on the application on cancer therapy.
Citation Information: Clin Cancer Res 2010;16(14 Suppl):B45.
Abstract B46: Proliferative suppression of anthraquinone derives emodin and aloe-emodin through selective targeting in prostate and breast cancer cells
Authors: Huang Pao-Hsuan , Lin Ho 
Published: June 2012

Abstract
Emodin and aloe-emodin are the main bioactive components of anthraquinones found in Chinese herbal medicine, Rhubarb (Rheum palmatum), and aloe-emodin is also abundant in the leaves of aloe vera. Although emodin and aloe-emodin are capable of inhibiting cancer cell proliferation or inducing apoptosis, the recent studies suggest that the molecular targets of these two anthraquinones are different. Emodin has been reported to suppress HER-2-overexpressing breast cancer cells proliferation through decreasing HER-2 tyrosine kinase activity. Besides, emodin affected androgen receptor (AR) transcriptional activity by preventing AR nuclear translocation and promoted AR degradation. Aloe-emodin has been found the antiproliferative effects on breast cancer cells which is through estrogen receptor (ER)-modulating ability. Interestingly, emodin and aloe-emodin share similar structure with different functions by hitting different targets. Therefore, the molecular mechanisms of aloe-emodin causing cancer cell death are interesting to explore. Here, three cancer cell lines were used in our experiments: LNCaP, a human prostate cancer cell line with AR expression; two human breast cancer cell lines: MDA-MB-453 with high expressions of HER-2 and AR; MCF-7 with low expressions of HER-2 and AR. In which, MCF-7 cells contain high expression level of ERα. Cells were treated with emodin or aloe-emodin for different time intervals and proliferation was determined. The results indicated that emodin decreased the proliferation of LNCaP and MDA-MB-453 which express high AR protein; however, MCF-7 with low AR protein were relatively insensitive to emodin treatment. Oppositely, aloe-emodin decreased cell proliferation in ER-positive MCF-7 cells but had no effects on LNCaP and MDA-MB-453 cells. Furthermore, the morphology of MCF-7 was dramatically changed after aloe-emodin treatment and cell death was apparently observed. The protein levels of HER-2, phospho-HER-2, and ErbB3 were decreased after aloe- emodin treatment while ERK was unaffected. In addition, the protein levels of ERα were reduced by aloe-emodin in dose-dependent manner; however, AR protein seems unaffected. In conclusion, our findings indicate that aloe-emodin selectively attacks targets in cancer cells and had potentials to treat HER-2/ER-positive breast cancer in the future.
Citation Information: Clin Cancer Res 2010;16(14 Suppl):B46.
Abstract B48: Immunohistochemistry and RT-PCR evaluation of fixative effects in a model tissue system
Authors: Millward Carl , Liu Mei-Lan , Jeong Jennie , Ambannavar Ranjana , Kaplan Hargita , Collin Francois , Baker Joffre , Cronin Maureen 
Published: June 2012

Abstract
The standard practice in hospital pathology laboratories is to preserve patient clinical tissue specimens as fixed, paraffin-embedded (FPE) tissue. FPE specimens are used for routine pathologic examination, immunohistochemistry (IHC) studies, and a variety of molecular diagnostic assays. The results of these studies assist in determining the patient's clinical status and in therapeutic decision making. However, the methodology for tissue fixation is not standardized across laboratories and a number of different tissue fixatives are currently commercially available. The use of different tissue fixatives may significantly affect the performance of IHC and molecular diagnostic assays.
The results of nine common tissue fixatives and their effects on both IHC- and RNA-based molecular assays are reported. Using human placenta as a model tissue system, nine common fixatives (B5, Bouin's, ethyl alcohol 70%, formalin, Hollandes, Penfix, Prefer, Zenker's, and zinc formalin) were compared for effects on six IHC assays and a panel of 42 gene targets by RT-PCR assays, as well as performance relative to fresh (RNAlater®) or frozen (OCT) unfixed tissue. The 42-gene panel assessed by RT-PCR included the six genes assessed by IHC. The IHC assays were scored using a semiquantitative method. For RT-PCR, raw assay scores were derived and subsequently normalized. Different fixatives resulted in varying effects on IHC and molecular assay performance. Per gene across each fixative, mRNA expression levels assessed by RT-PCR assays demonstrated wide variation, which could be largely corrected for by normalization. Variation in immunoreactivity as a function of tissue fixative was also observed with IHC assays. Compared to IHC, RT-PCR assays demonstrated greater sensitivity and were able to detect lower levels of gene expression, when the IHC assay gave negative results. Interestingly, fixative related effects were not always similar between IHC and RT-PCR assays. Therefore, it is recommended that the effects of tissue fixation be taken into consideration when performing data analysis and making comparisons between IHC and molecular diagnostic assays.
Citation Information: Clin Cancer Res 2010;16(14 Suppl):B48.
Abstract B49: The role of LKB1 as a tumor suppressor in esophageal squamous cell cancer
Authors: Tzao Ching , Hsueh An-Li , Chen Ban-Hen , Guo Yaw-Wen , Lee Guang-Guan Sun, Shih-Chun 
Published: June 2012

Abstract
Background: LKB1, also known as STK11, encodes serine/threonine kinase 11 that is frequently mutated in the Peutz- Jeghers syndrome. LKB1 functions as a tumor suppressor in a variety of human cancers, including colon and lung. We investigated the functional role of LKB1 in esophageal squamous cell carcinoma (ESCC).
Methods: Resected ESCC tumors from 65 patients were used for immunohistochemistry to determine LKB1 expression. Cytotoxicity (MTT) assay was used to test chemosensitivity to common chemotherapeutic agents for ESCC, including cisplatin, 5-FU and taxol, along with migration assay in selected ESCC cell lines (KYSE 170 and KYSE 510, kindly provided by Dr. Yutaka Shimada at University of Toyama, Japan). LKB1 was overexpressed in KYSE 170 cells and was knocked down in KYSE 510 cells using human LKB1 (pCMV6-XL5- cDNA, OriGene) and its shRNA (OriGene), respectively. Expression of LKB1, E-cadherin and p53 pathway-related proteins (ie p21 and PUMA) in LKB1-overexpessed or knock-down cells and its vector controls by Western blot analysis. Mice tumor xenografts with LKB1- overexpressed KYSE 170 cell line were used to test tumor growth and their chemosensitivity in vivo with comparisions to the vector controls. Pearson's correlation was used to correlate clinicopathologic variables with LKB1 expression along with survival analyses by log-rank test, Kaplan-Meier survivial analysis and multivariate analysis with Cox proportional hazards regression model.
Results: LKB1 expression correlated inversely with tumor staging (P = 0.003). Patients with high expression of LKB1 showed better survival compared to those with low expression (P = 0.0002). When further examined by multivariate analysis, LKB1 expression correlated positively with patients’ survival (P = 0.004) with a hazard ratio (HR) of 3.415. Compared with vector control and LKB1 knockdown KYSE 510 cell line, cell proliferation was significantly suppressed in LKB1 overexpressed KYSE 170 cells with an upregulation of p21 and p53-upregulated modifier of apoptosis (PUMA). LKB1 overexpression increased E-cadherin expression in KYSE 170 cells with an inihibition in their migration. LKB1 overexpressed KYSE 170 cells were more sensitive to chemotherapeutic agents in vitro and in vivo compared to the vector controls.
Conclusions: LKB1 expression in resected ESCC predicted patients’ outcome and it served as an independent survival predictor. LKB1 overexpression increased chemosensitivity with a decrease in cell proliferation and migration while upregulating p53-pathway related suppressors and E-cadherin in ESCC cells. Our results suggested a role of LKB1 as a tumor suppressor gene in ESCC.
Citation Information: Clin Cancer Res 2010;16(14 Suppl):B49.
Abstract B5: Sequence analysis of HSP90-encoding genes in breast tumor tissue identifies a novel 9 bp deletion in HSP90AB1
Authors: Lichter David I. , Danaee Hadi , Tayber Olga , Sintchak Michael , Kuida Keiske , Atienza Josephine M. , Miyake Hiroshi , Blakemore Stephen J. 
Published: June 2012

Abstract
The 90 kDa heat-shock protein (HSP90) functions as a ubiquitous cellular chaperone in cells, and is required for the function and stability of many client proteins such as ERBB2, EGFR, BCR-ABL, MET, androgen and estrogen receptors, BRAF and HIF-1α.1 There are four primary genes that encode for HSP90 in humans: HSP90AA1 and HSP90AB1 (cytosolic), HSP90B1 (endoplasmic reticulum) and TRAP1 (mitochondrial). Increased HSP90 expression has been associated with poor prognosis in cancer, and inhibiting HSP90 can lead to degradation of many oncogenic client proteins via the proteasome pathway.1
HSP90 has been the subject of intense drug discovery activities, with several therapeutics under clinical investigation.2 However, the data on single nucleotide polymorphisms (SNPs) and potential somatic mutations within the HSP90-encoding genes in tumor tissue is limited. Target allelic variation can alter drug binding and therapeutic response, as demonstrated by Iressa™'s reported specific efficacy in EGFR-mutant non-small cell lung cancer patients.3 Therefore, it is critical to understand target allelic variance as part of a drug development program.
To facilitate drug development efforts around HSP90, we investigated allelic variation within the coding regions of HSP90AA1 (second isoform) and HSP90AB1 genes in 49 formalin-fixed paraffin- embedded human breast tumor samples. Sample SNP data were compared to control data from the NCBI Entrez SNP database. We observed four synonymous changes within HSP90AA1, and two synonymous changes within HSP90AB1. Intriguingly, we also observed a heterozygous 9-base deletion in exon 1 of HSP90AB1 within one breast tumor patient sample. This deletion results in an alanine&gt;valine substitution at amino acid 22 and a loss of amino acid 23-25 (glutamine, leucine, methionine). The deleted region includes one turn of a 3-turn alpha helix, located within the N-terminal domain structure of the HSP90AB1 protein. Full details of HSP90 allelic variance within breast tumor tissue, and a discussion of the potential functional significance of the deletion, will be provided.
References:
1. Pearl LH, Prodromou C, Workman P. The HSP90 molecular chaperone: an open and shut case for treatment. Biochem J. 2008;410:439-53.
2. Hahn JS. The HSP90 chaperone machinery: From structure to drug development. BMB Reports. 2009;42(10):623-30.
3. Sequist LV, Bell DW, Lynch TJ, Haber DA. Molecular predictors of response to epidermal growth factor receptor antagonists in non- small-cell lung cancer. J Clin Oncol. 2007;25(5):587-95.
Citation Information: Clin Cancer Res 2010;16(14 Suppl):B5.
Abstract B50: A new class of diazonamide analogs with improved antitumor activity
Authors: Li Lin , Wei Qi , Zhou Ming , Ramesh Vijayashree , Wang Xiaodong , Harran Patrick G. , Wang Lai 
Published: June 2012

Abstract
Diazonamide A is a natural product originally isolated from a marine organism. It potently induces G2/M cell cycle arrest. Its molecular mode of action is not fully understood but its potential as a cancer therapeutic is high. We previously reported that AB5, a close analog of diazonamide A, exhibits potent anti-tumor activity in mouse xenograft models. Tumor regression occurs in the absence of systemic toxicity typical of anti-mitotic chemotherapy. Here we show for the first time that the natural diazonamide compound possesses strong tumor killing activity in vivo xenograft models. To streamline our diazonamide synthesis and to define a minimal pharmacophore, we prepared a series of truncated structures. One of these, JP1838, was found to be as potent as AB5. Its simplified structure and shortened synthesis allowed for extensive structure activity relationship analyses. Several modifications markedly improved activity. One analog, JP2295, is &gt;20 fold more potent than AB5 in a MIA Paca-2 pancreatic cancer xenograft model. More importantly, in HPAC pancreatic cancer and HCT-116 colon cancer xenograft models, JP2295 demonstrates greater efficacy and less toxicity than docetaxel and vinorelbine. Safety studies were therefore carried out in NIH Swiss mice. At doses10-fold higher than required for strong efficacy, JP2295 does not exhibit toxicities common to docetaxel and vinorelbine treatments. These include body weight loss, neutropenia, and myelosuppression. Such a large therapeutic window is unique for a small molecule antimitotic and suggests further development is warranted.
Citation Information: Clin Cancer Res 2010;16(14 Suppl):B50.
Abstract B53: Cytotoxic effect of 21kDa protein and antitumor effect of 31KDa protein derived from mushroom, schizophyllum commune
Authors: Wu Yu-Sheng , Chang Po-Yen , Chen Su-Nan 
Published: June 2012

Abstract
The present study attempts to the purified proteins from mushrooms that way activate and stimulate the proliferation of immune cell, resulting in the onset phagocytosis and nature killer cell (NK cell) activity, and promotes the cytotoxicity of tumor cell. In this study 21 and 30 KDa protein from fermentation liquid of the mushroom Schizophyllum commune were purified that exhibit a distinct cytotoxic capability: The 21 KDa protein was demonstrated to be capable of stimulating the NK cell activity, while the 30 KDa protein prevent the proliferation of Lewis lung carcinoma in vitro. Furthermore it was also forward that 21 KDa protein stimulate the the proliferation of mouse splenocyte at a various concentration levels without agglutinating the red blood cell of ICR mouse. Our result showed that when we used concentration level of 27 µg/ml protein, a significant activity of NK cell was obtained (p&lt; 0.05). In addition 30 KDa protein may activate macrophage RAW264.7 enhance to production of nitric oxide and TNF-α, However, the production of nitric oxide by RAW264.7 was relied on the dose of 30 KDa protein in vitro. Based on the results, the purified proteins protein from Schizophyllum commune were potent immue stimulants and has a potential for development as a novel pharmacological agent.
Citation Information: Clin Cancer Res 2010;16(14 Suppl):B53.
Abstract B54: Molecular basis of oncogene cooperation in liver cancer
Authors: Balakrishnan Asha , Lim Lionel , Cairo Stefano , Chandriani Sanjay , Jones Kirk D. , Buendia Marie-Annick , Goga Andrei 
Published: June 2012

Abstract
Combinations of genetic alterations in cancer genes lead to aberrant signaling properties and drive cellular transformation. Whether each oncogene gives rise to unique signals or combinations of oncogenes lead to new properties of cancer cells remains unclear. Using cell-based and animal model systems it has been shown that certain oncogenes can cooperate with each other to induce a fully malignant tumor phenotype. In addition, the combination of oncogenes and the extent of cooperation between them to give rise to a tumor may vary in different cancers.
Cooperativity between MYC and RAS oncogenes has been observed in different cancer types. MYC is often overexpressed and sometimes amplified in cancer, while, activating RAS mutations occur in about 30% human cancers. Hepatocellular carcinoma (HCC) is among the four leading causes of cancer-related death. Currently, except for early surgical intervention or liver transplantation, no effective cures exist. Overexpression of both MYC and activated HRAS together in primary human liver tumors has been associated with aggressive forms of liver cancer with an especially poor prognosis. However, a systematic approach to understanding MYC and RAS cooperation in liver cancer has not yet been undertaken. We have discovered that transgenic mice overexpressing MYC, RAS or both MYC and RAS in their liver, give rise to distinct liver tumors. MYC and RAS coexpression led to faster tumor development and decreased survival. To gain a comprehensive view of the molecular changes that contribute to MYC and RAS oncogene cooperation in de novo liver tumors, we combined the conditional transgenic models of liver cancer with global gene expression, signaling pathway analyses and functional studies. Comparisons were made to clinically annotated human tumors and key pathways validated in cell lines and animal models.
We show that tumors driven by either oncogene or a combination of both are phenotypically and molecularly distinct from each other with differential regulation of multiple genes and pathways. Our work suggests that MYC and RAS cooperate through specific genes, such as CCNE1 and multiple signaling pathways including proliferation, apoptosis, angiogenesis and multiple metabolic pathways, to contribute to liver cancer development. We also show molecular alterations across signaling pathways are comparable between mouse and human liver cancers. Primary human liver tumors can be segregated into distinct subsets based on differentially regulated gene sets from cooperating MYC and RAS tumors. These results indicate that molecular changes underlying MYC and RAS cooperation may serve as ideal molecular markers and therapeutic targets for liver cancer.
Citation Information: Clin Cancer Res 2010;16(14 Suppl):B54.
Abstract B7: Genome-wide analysis of CpG methylation for the radiosensitivity
Authors: Kim Eun-Hye , Park Ae-Kyung , Jung-Hyuck Ahn , Park Woong-Yang 
Published: June 2012

Abstract
Epigenetic regulation is one of the most important mechanisms for the development and the progression of human cancers. To understand the epigenetic control of differential sensitivity to radiotherapy, we investigated the DNA CpG methylation profiles of normal lung epithelial cells and lung cancer cell lines using DNA microarray. Among 27K CpG probes in Illumina BeadChip, we found CpG sites of 1091 genes were differentially methylated in radiosensitive H460 and radioresistant H1299 cell lines against normal lung cells. Among the hypermethylated genes in H1299 cells, promoter CpG methylation and mRNA expression of SERPINB5 and S100A6 were validated by methylation-specific PCR and quantitative RT-PCR, respectively. When we suppressed the expression of these two genes using siRNA in H460 cells, the survival fraction of H460 cells were increased upon ionizing radiation. Promoter CpG sites of CAT and BNC1 were hypomethylated in radioresistant H1299 cells and the introduction of siRNA against CAT or BNC1 in H1299 cells could reduce the resistance to ionizing radiation. Here we report the differentially methylated genes by genome-wide CpG methylation profiling in two lung cancer cell lines, which might prove the epigenetic regulation of radiosensitivity in lung cancer cells.
Citation Information: Clin Cancer Res 2010;16(14 Suppl):B7.