bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1244: Differential requirements for the receptor tyrosine kinase c-Met in scirrhous gastric carcinoma cell lines
Authors: Yoshida Nachi , Yamaguchi Hideki , Muroi Emi , Takanashi Miho , Fukami Kiyoko , Sakai Ryuichi
Published: August 2012

The prognosis of patients with scirrhous gastric carcinoma (SGC) has been very poor. SGC cells do not form obvious tumor mass, but cause diffuse infiltration and eventually rigid thickening of the gastric wall. Furthermore, SGC cells frequently infiltrate through gastric serosa and cause peritoneal dissemination. However, the mechanisms underlying the progression of SGC have not yet been fully elucidated. In the present study, we performed immunoblotting and proteomic analyses of tyrosine-phosphorylated proteins in differentiated non-SGC cell lines (MKN7, MKN1, and MKN74) and poorly differentiated or SGC cell lines (MKN45, NUGC-4, KATO III, HSC59, 58As9, HSC44-PE, and 44As3) to identify signaling pathways and molecules that are characteristics of SGC. We found that the tyrosine kinase receptor c-Met is overexpressed and highly phosphorylated in SGC cell lines. c-Met is a cell surface receptor for HGF and implicated in the growth, survival, invasion, and metastasis of various human cancers. Amplification of c-Met gene in SGC was also previously reported. We analyzed the downstream signaling pathways of c-Met in SGC cells by using two c-Met inhibitors PHA-665752 and JNJ-38877605. Treatment of 58As9 cells with the c-Met inhibitors markedly inhibited phosphorylation of Erk, Akt, and Stat3, but promoted phosphorylation of Src. In contrast, 44As3 cells treated with the c-Met inhibitors showed no significant changes in phosphorylation of these molecules, in spite of successful inhibition of c-Met phosphorylation. Reflecting these observations, c-Met inhibitors blocked cell proliferation and caused morphological alterations in 58As9 cells but not in 44As3 cells. Similar results were obtained when MKN45 and NUGC-4 cells were analyzed in the same manner: MKN45 cells but not NUGC-4 cells were sensitive to c-Met inhibition. These results suggest that SGC can be classified into two subtypes according to their dependencies on the c-Met signaling pathway. Further studies are now conducted to identify therapeutic targets in c-Met-independent SGC cell lines.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1244. doi:1538-7445.AM2012-1244
Abstract 1249: Modulation of epidermal growth factor induction of migration by integrin-linked kinase
Authors: Dagnino Lina , Ho Ernest
Published: August 2012

Epidermal growth factor (EGF) signaling is central for proliferation, survival and motility in epithelial cells. Cell migration is an obligatory prerequisite for metastasis and requires the development of front-rear polarity. EGF stimulation in various epithelial cell types induces formation of protrusions and migration via RhoG and Rac1 activation. We now demonstrate that treatment of primary epidermal keratinocytes with EGF, but not with other growth factors that promote cell migration, induces cell polarization mediated by complexes containing RhoG, integrin-linked kinase (ILK) and “Engulfment and Cell Motility-2” (ELMO2). This process requires the tyrosine kinase activity of the EGF receptor. Further, ELMO2, ILK, Rac1 and integrin beta1 are obligatory effectors in this pathway, as inactivation or knockdown of the genes or mRNA encoding these proteins abrogates the stimulatory effect of EGF. Thus, we have identified a novel pathway that links EGF receptor stimulation with RhoG/ELMO2/ILK complexes and activation of Rac1 in the acquisition of front-rear polarity.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1249. doi:1538-7445.AM2012-1249
Abstract 1251: A role for lactate dehydrogenase in the c-Met/HGF signaling axis
Authors: Gray Alana L. , Minutolo Filippo , Cardelli James A.
Published: August 2012

Tumor cells often display a glycolytic phenotype, even in the presence of oxygen; a phenomenon known as the Warburg effect. The ability of cancerous cells to perform aerobic glycolysis is unique when compared to non-cancerous cells, and therefore, presents a possible therapeutic target for elimination of cancer cells that rely on aerobic glycolysis. Activation of the receptor tyrosine kinase, c-Met, by hepatocyte growth factor (HGF) is a major contributing event in the progression of prostate cancer (PCa). Signaling through this receptor leads to increased cell motility, proliferation, invasion and metastasis. Studies have shown that targeting this signaling axis can greatly reduce the number of bone metastases that arise from primary PCa tumors. Oxamate, a lactate dehydrogenase (LDH) inhibitor, and 2-deoxyglucose (2-DG) are known glycolytic inhibitors. Our studies have found that oxamate reduced c-Met activation and HGF-induced cell motility, while 2-DG had no effect. In order to confirm that oxamate was targeting LDH-A or LDH-B, we created LDH-A, LDH-B, and LDH-A/B knockdown (KD) DU145 cells. Although all of the clones used in the experiments had greater than 70% KD, we were unable to recapitulate the effects seen with oxamate. We believe that this could be due to incomplete KD. In support of this, use of a specific LDH-A (πFly-21) inhibitor significantly reduced c-Met activation and HGF-induced cell motility. Together, these data support a role for LDH-A in facilitating HGF-induced c-Met activation. Because oxamate is a direct LDH inhibitor, we hypothesized that oxamate would have a greater reduction in lactate (LA) export from cells than 2-DG; however, both, oxamate and 2-DG reduced LA production by approximately 75% in DU145 prostate cancer cells. Therefore, the ability of oxamate to reduce c-Met activation is not apparently due to a decrease in LA export. However, it is possible that LA import via monocarboxylate transporter 1 (MCT1) activity may be important for c-Met activation and downstream signaling events. In support of this, KD of MCT1 resulted in reduced c-Met activation and blocked HGF-induced cell motility. These data indicate a potential connection between LDH activity/lactate import and the c-Met signaling axis, suggesting that inhibition of these processes may be a new mechanism for preventing c-Met driven metastatic events.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1251. doi:1538-7445.AM2012-1251
Abstract 1258: High-density protein lysate arrays: an essential tool in assessing antibody specificity for clinical applications
Authors: Baruch Dror I. , Ma Donghui , Shu Youmin , Sun Zairen , He Wei-Wu
Published: August 2012

Antibodies for clinical applications require rigorous scrutiny qualifying them for diagnostics or therapeutic use. However, this is a lengthily and complicated process that provides only limited conformation. Protein microarrays are new tools that can determine the specificity and reactivity of Abs and help identifying their target in less than a day. We created a high-density protein array comprised from more than 10,000 over-expressed protein lysates made in human HEK293T cells. We tested more than 15 available antibodies to two cancer targets; the excision repair cross-complementation group 1 (ERCC1) and the receptor tyrosine kinase ERBB2 (Her2/neo). Our results demonstrated the ability of the lysate array in determining the specificity of antibodies with a single fast and easy assay. ERCC1 is a predictor of resistance to platinum based drugs and for poor prognosis in cancer. The commonly used anti ERCC1 antibody, mAb 8F1, is known to give non-specific cytoplasmic staining and to cross-react with an unknown protein of similar size. We tested 10 commercially available Abs to ERCC1 and identified four mono-specific ones (TrueMAb OriGene). Most of these specific Abs gave higher reactivity than clone 8F1. With this test we also identified a cytoplasmic protein of appropriate molecular weight that is cross-reacting with mAb 8F1. The above results were corroborated by WB analysis and IHC assays supporting the validity of this type of assays. We extended our tests to include anti ERBB2 Abs as this important biomarker is indicative for the use and response to the drug Herceptin. Our tests included mono and poly clonal antibodies and clone 4B5, a rabbit mAb currently used for IHC diagnostic. We found clone 4B5 to be reactive with two additional proteins besides ERBB2, one of them is ERBB4. We also tested a rabbit polyclonal anti ERBB2 serum and found it to be reactive with additional proteins unrelated to those recognized by mAb 4B5. Three out of the four mouse mAbs tested (TrueMAb OriGene) were determined to be specific. We submit that the over-expression protein lysate arrays can establish the reactivity and specificity of Abs and identify unknown targets. The speed and convenience of these assays make them an important tool in developing Abs for clinical use.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1258. doi:1538-7445.AM2012-1258
Abstract 1261: A mesodissection system for accurate, rapid, and economical recovery of tissue from slide mounted tissue sections
Authors: Adey Nils B. , Parry Robert J. , Birch Lilia , Paxton Christian N. , Ghaffari Siavash , Herrmann Mark G. , Geiersbach Katherine B.
Published: August 2012

We have developed a prototype system for slide mounted tissue dissection capable of resolution between manual methods (i.e. scraping tissue off of microscope slides) and laser capture microdissection (LCM); here we test the performance of this system. The mesodissection instrument employs a specialized milling tip that simultaneously dispenses and aspirates liquid in order to capture tissue fragments displaced from the slide surface. The accompanying software is capable of transferring electronically indicated target regions between neighboring tissue sections to guide the dissection process. Resolution and accuracy of the system were accessed by microscopic inspection of the dissected region; resolution is the smallest recoverable area and accuracy is the difference between the actual dissected region and the desired region. Purity is defined as the percentage of desired tissue retrieved from a FFPE tissue block made from a human tumor xenografted into mouse, and accessed using real-time PCR amplification of species-specific repetitive DNA elements, as well as unique genomic regions. Efficiency is defined as total DNA recovered relative to manual methods, as quantified by PicoGreen fluorescence. Currently, the system is capable of 0.3 mm resolution and accuracy better than 0.1 mm compared to a desired boundary. Purity is greater than 90% at 0.1mm from the mouse-human tissue boundary. Efficiency is comparable to manual methods when virtually all tissue is recovered from the region of interest. Improvements to the current prototype are ongoing with the goal of less than 0.1 mm resolution. The mesodissection system provides an inexpensive alternative to the limited resolution of manual dissection methods and the high cost and low recovery efficiency of LCM. Digitally targeted dissection using tissue sections derived from adjacent portions of a tissue block allow for determination of a region of interest from a slide optimized for visualization and recovery from a slide optimized for dissection.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1261. doi:1538-7445.AM2012-1261
Abstract 1281: MALDI imaging mass spectrometry of three-dimensional cell culture systems
Authors: Hummon Amanda B. , Li Haohang , Weaver Eric
Published: August 2012

3D cell cultures have increased complexity compared to simple monolayer and suspension cultures, recapitulating the cellular architecture in the body. For example, many colon cancer cell lines form rounded heterogeneous spheroid structures that mimic the pathophysiological properties of tumors when grown under appropriate cell culture conditions. Classical imaging methodologies, like immunohistochemistry, are commonly used to examine the distribution of specific species within the spheroids. However, there is a need for an unbiased discovery-based methodology that would allow examination of protein/peptide distributions in 3D culture systems, without a need for prior knowledge of the analytes. We have developed MALDI imaging mass spectrometry protocols to examine protein distributions in 3D cultures models. Using the HCT 116 colon carcinoma cell line, we have grown spheroids measuring 1 mm in diameter for MALDI IMS imaging. We detect changes in the spatial distribution of proteins across the spheroids by IMS. While most proteins are distributed across the structures, some are localized to either the proliferative outer rim of the spheroids or to the central necrotic core. We are now expanding our studies to map the changes in protein distribution that accompany knockdown of E-cadherin (CDH1). We are inserting inducible shRNAs targeting CDH1 into HCT 116 cells. Once our cells stably express the shRNAs, we will grow spheroids and then trigger knockdown of CDH1 expression. We will map changes in protein expression over a time course using the MALDI imaging mass spectrometry protocols we have developed. As CDH1 is a critical component of cell-cell junctions, we anticipate that its reduction will trigger phenotypic changes in the spheroid structures. In addition, we expect to see a shift in transcriptional activity that correlates with activation of the Epithelial-Mesenchymal Transition. Our unbiased protein mapping technology enables us to examine previously observed protein changes that result from CDH1 reduction.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1281. doi:1538-7445.AM2012-1281
Abstract 1282: NCI's Clinical Proteomic Tumor Analysis Consortium
Authors: Rivers Robert C. , Mesri Mehdi , Kinsinger Chris , Boja Emily , Hiltke Tara , Rodriguez Henry
Published: August 2012

Mission: The Clinical Proteomic Tumor Analysis Consortium (CPTAC) is a comprehensive and coordinated effort to accelerate the understanding of the molecular basis of cancer through the application of robust, quantitative, proteomic technologies and workflows. Goals: The overarching goal of CPTAC is to improve our ability to diagnose, treat and prevent cancer. To achieve this goal in a scientifically rigorous manner, the National Cancer Institute (NCI) launched CPTAC to systematically identify proteins that derive from alterations in cancer genomes and related biological processes, and provide this data with accompanying assays and protocols to the public. Genomics initiatives such as The Cancer Genome Atlas (TCGA) have characterized and sequenced the genomic alterations from several types of cancer. CPTAC will leverage its analytical outputs by producing a unique continuum that defines the proteins translated from cancer genomes in order to link genotype to proteotype and ultimately to phenotype. Scientific Approach: The structure of CPTAC is designed to facilitate the efficient implementation of a two-step developmental pipeline, Discovery and Verification. The pipeline originates with the CPTAC Resource Center, which will provide a set of high-quality, genomically characterized clinical biospecimens from patients with a single type of cancer. The Discovery Unit of each Proteome Characterization Center (PCC) will use a set of proteomic technologies to comprehensively analyze the protein composition of this set of biospecimens including mapping proteome to genome and detecting and quantifying protein products that correspond to genomic aberrations. All data from the Discovery Units will be shared within the network via the CPTAC Data Center. Based on this aggregate data set, each Discovery Unit will select and prioritize cancer-related proteins for potential use in the verification step. The selected lists of prioritized proteins by the Discovery Units will be consolidated and collectively prioritized. The Verification Unit of each PCC will develop targeted assays against corresponding protein targets as assigned by the verification plan. The Verification Units will then verify the biomarker candidates by performing these assays in clinically relevant cancer biospecimens (provided by the CPTAC Resource Center). Data from these verification studies will be shared via the CPTAC Data Center. These verified proteins will serve as high-value targets to other initiatives involved in clinical qualification studies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1282. doi:1538-7445.AM2012-1282
Abstract 1283: A study towards identification of plausible protein markers of squamous cell carcinoma
Authors: Mahajan Manish , Manral Pallavi , Saraswat Mayank , Shukla N K. , Srinivasan A , Yadav Savita
Published: August 2012

Oral cancer is a group of carcinoma that accounts for most common cancer related morbidity in India and 6th most common in western world. Use of Clinical proteomics is a novel way of studying differential proteins in diseased and non- diseased states. 2 - Dimensional Gel Electrophoresis followed by mass spectrometry was used to study the differential protein expression in case of squamous cell carcinoma of buccal pouch using human whole saliva as sample. It was found that there was consistent over - expression of three proteins viz., Cytokeratin type I, Cytoskeletal Associated Protein −2 and a hypothetical protein. Elevation of cytokeratin expression is a well-known tool for immunohistological staining for various cancers of epithelial origin. Cytoskeletal Associated Protein −2 is p53 target genes whose functions are still under scrutiny but related to microtubule stabilization during mitosis. This may be implicated in causing aneuploidy in cancer cell, thus, affecting their overall prognosis. This finding in other cases may be used as a method to segregate cases of buccal pouch cancer as poor prognosis and hence, early intervention and better treatment outcome. Over expression of hypothetical protein in our results still needs further experimentation to vindicate our findings.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1283. doi:1538-7445.AM2012-1283
Abstract 1285: A functional liaison between E2F and aberrant ETS oncogenes
Authors: Bilke Sven , Schwentner Raphaela , Fan Yang , Kauer Max , Walker Robert L. , Kovar Heinrich , Melyzer Paul S.
Published: August 2012

Timing, mode and amplitude of gene regulation depend on the tissue specific dynamic composition of transcription factor complexes. Abnormalities of the constituents of the complex are expected to modify the regulatory behavior of the entire module. Here we report a novel E2F-ETS proliferation control module in Ewing's sarcoma. FLI1 and other ETS factors are frequently found to be fused to EWS in this highly aggressive pediatric cancer of the bone. In a genome-wide localization analysis of EWS/FLI1 as well as E2F3 by ChipSeq, two patterns associated with distinct gene sets and modes of regulation were identified and integrated with gene expression data. EWS/FLI1 significantly colocalized with E2F3 to proximal promoters of activated proliferation genes while EWS/FLI1 binding independent of E2F3 occurred predominantly distant to repressed differentiation genes. We find that this key module of the transcription factor network underlying Ewing's sarcoma is of general importance and not limited to this specific ETS driven neoplasm. Recently, prostate cancer was shown to frequently harbor fusions of the ERG gene. Here we demonstrate that the ETS/E2F3 complex is also present in VCap prostate cancer cells, identify a common set of genes responsive to this module and computationally show that this set of core-responders is involved in proliferation control and translation. Acknowledgement: This research was supported in part by the Intramural Research Program of the NIH, National Cancer Institute, Center for Cancer Research.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1285. doi:1538-7445.AM2012-1285
Abstract 1292: Mutually exclusive expression of SOX2 and SOX9 in lung adenocarcinoma cells and its implications
Authors: Jiang Shih-Sheng , Fang Wen-Tsen , Chang I-Shou , Huang Chih-Ting
Published: August 2012

SOX family genes play critical roles in embryonic development, cell fate determination, differentiation, and proliferation. Some members of the SOX family, including SOX2 and SOX9, have been shown as hall marks of lung cancers. However, their roles in lung cancer formation or progression still need to be explored. Here we show an unique expression pattern of SOX2 and SOX9 in lung cancer cells. Using a series of previously established lung adenocarcinoma cell sub-lines which were sequentially selected for increasing cell invasiveness, we found that SOX9 was abundant in highly tumorigenic and invasive sub-lines whereas absent in less tumorigenic and low invasive ones. Interestingly, SOX2 and SOX9 were mutually exclusively expressed among those sub-lines. Forced expression and gene silencing experiments in those cell lines indicated that, while SOX9 is important for cancer cell proliferation, SOX2 is involved in regulation of cell invasion. The involvoed molecular pathways subject to regulations by SOX9 and SOX2 have been partially elucidated and will be demonstrated.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1292. doi:1538-7445.AM2012-1292
Abstract 142: Tumor suppressor BRCA1 epigenetically controls oncogenic miRNA-155
Authors: Chang Suhwan , Sharan Shyam
Published: August 2012

BRCA1, a well-known breast and ovarian cancer susceptibility gene with multiple interacting partners, is predicted to have diverse biological functions. However, to date its only well-established role is in the repair of damaged DNA and cell cycle regulation. In this regard, the etiopathological study of low penetrant variants of BRCA1 provides an opportunity to uncover its other physiologically important functions. Using this rationale, we studied the R1699Q variant of BRCA1, a potentially moderate risk variant, and found that it does not impair DNA damage repair but abrogates the repression of miR-155, a bona fide oncomir. We further show that in the absence of functional BRCA1, miR-155 is up-regulated in BRCA1-deficient mouse mammary epithelial cells, human and mouse BRCA1-deficienct breast tumor cell lines as well as BRCA1 mutant tumors. Mechanistically, we found that BRCA1 represses miR-155 expression via its association with HDAC2, which deacetylates H2A and H3 on the miR-155 promoter. Finally, we show that over-expression of miR-155 accelerates whereas the knockdown of miR-155 attenuates the growth of tumor cell lines in vivo. Taken together, our findings demonstrate a new mode of tumor suppression by BRCA1 and reveal miR-155 as a potential therapeutic target for BRCA1-deficient tumors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 142. doi:1538-7445.AM2012-142
Abstract 143: CD24 induced miR-21 regulation is mainly mediated through Src, and both (CD24, Src) are post-transcriptionally downregulated by miR-34a
Authors: Muppala Santoshi , Mudduluru Giridhar , Leupold Jöerg H. , Sleeman Jonathan P. , Allgayer Heike
Published: August 2012

Cancer is a complex disease and multi step process evolving from malfunctions of complex molecules and their networks which regulate this process. Understanding these networks will be essential to combat cancer. In this study, we focussed on key players in such networks. CD24, Src and miR-21 have been described as adverse prognostic markers in a panel of malignancies. CD24 interacts and co-localizes with Src in lipid rafts. Pdcd4 and miR-34a have been described as tumor suppressor genes which are down regulated in different tumor types. In a series of colon and breast cancer cell lines, we found that CD24 activates Src and inducing the activation of c-Jun and expression of c-Jun and c-Fos. Furthermore, we show here that it regulates the promoter activity of miR-21 and its expression, which leads to inhibition of miR-21 targeted tumor suppressor genes. Similar results were found for constitutively active src. Co-transfection of a CD24 expression construct and an si-RNA silencing of Src showed that CD24 mediated upregulation of miR-21 is mediated through Src. Taken together, our results suggest that CD24 expression upregulates miR-21 in a Src dependent manner. Furthermore, we found that miR-34a targets the CD24- and Src-3′UTR as shown by luciferase assays performed either with wild type or mutated miR-34a seed sequences within these 3′UTRs. MiR-34a post-transcriptional inhibition of CD24 and Src downregulated the activation of c-Jun and expression of c-Jun and c-Fos, inhibited miR-21 promoter activity and expression, and induced the expression of tumor suppressor genes Pdcd4 and PTEN significantly (p=0.05). Furthermore, miR-34a inhibited Src induced colony formation, migration and invasion. Our results revealed complex networking between essential players in the progression of solid tumors especially colorectal cancer. These findings could help to focus new therapeutic approaches to overcome this and further solid cancer entities.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 143. doi:1538-7445.AM2012-143
Abstract 1446: Sonic hedgehog-associated medulloblastoma arising from the cochlear nuclei of the brainstem
Authors: Grammel Daniel , Warmuth-Metz Monika , von Bueren André , Kool Marcel , Pietsch Torsten , Kretzschmar Hans , Rowitch David , Rutkowski Stefan , Pfister Stefan , Schüller Ulrich
Published: August 2012

Medulloblastoma is a malignant brain tumor of childhood that comprises at least four molecularly distinct subgroups. We have previously described that cerebellar granule neuron precursors may give rise to the subgroup with a molecular fingerprint of Sonic hedgehog (Shh) signaling. Other recent data indicate that precursor cells within the dorsal brain stem may serve as cellular origins for Wnt-associated medulloblastomas. In order to see whether Shh-associated medulloblastomas are also able to develop in the dorsal brainstem, we analyzed two lines of transgenic mice with constitutive Shh signaling in hGFAP- and Math1-positive brainstem precursor populations, respectively. Our results show that in both of these lines, medulloblastomas arise from granule neuron precursors of the cochlear nuclei, a derivative of the auditory lower rhombic lip. This region is distinct from derivatives of precerebellar lower rhombic lip where medulloblastoma arise in mice with constitutive-active Wnt signaling. With respect to their histology and the expression of appropriate markers, Shh tumors perfectly resemble the human counterparts. Moreover, we find that in a series of 63 human desmoplastic medulloblastomas, 19 (30%) have a very close contact to the cochlear nuclei on MRI imaging. In conclusion, we suggest that precursors of the rhombic lip which may either develop into cerebellar or into cochlear granule neurons, may give rise to Shh-associated medulloblastoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1446. doi:1538-7445.AM2012-1446
Abstract 1457: Valproic acid enhances radiation therapy by protecting normal hippocampal neurons and sensitizing malignant glioblastoma cells
Authors: Sweeney Kyle , Bhave Sandeep , Hu Rong , Fong Jerry , Hallahan Dennis , Thotala Dinesh Kumar
Published: August 2012

Neurocognitive deficits are devastating sequelae that follow cranial irradiation in patients with medulloblastoma and leukemia. Valproic acid (VPA) has been used effectively as a neuroprotector in various neurological insults. In the present study we demonstrate that VPA could be used to protect hippocampal neurons from the damaging effects of radiation. The effect of VPA pretreatment on cell death was examined using clonogenic survival assays. Mouse hippocampal neurons, HT-22 were treated with 0.6 mM VPA for 7 days prior to irradiation. A significant increase in survival was seen in HT-22 cells treated with VPA compared to cells treated with radiation alone. In contrast, VPA treatment decreased the survival of irradiated cancer cells, D54 and GL-261 compared to radiation alone. To elucidate the mechanism of this selective increased survival in normal hippocampal cells we monitored for program cell death by Annexin V-FITC or DAPI staining. Irradiated HT-22 cells which were pretreated with VPA demonstrated 2 fold decrease in apoptosis than irradiated cells. Similar results were obtained using irradiated mice. Seven-days old C57BL6J pups were either irradiated with the single dose of 7 Gy or treated with VPA (200mg/Kg) followed by 7Gy irradiation. VPA pretreatment protected hippocampal neurons from radiation-induced apoptosis as demonstrated by counting the pyknotic nuclei in the subgranular zone of the hippocampal region. Western immunoblotting of HT-22 cells revealed that VPA not only inhibited HDAC, but also inhibited glycogen synthase kinase-3β (GSK-3β), an enzyme required for apoptosis. A heterotopic glioma model of GL-261 was used to evaluate the tumor growth delay following treatment with VPA (200 mM) and radiation (five fractions of 2Gy). VPA alone delayed the tumor growth; however VPA in combination with radiation significantly delayed tumor growth. In conclusion, VPA protected hippocampal neurons from radiation-induced damage in vitro and in vivo. This protection is specific to hippocampal neuronal cells and not to cancer cells. The molecular mechanism could involve enzymatic inhibition of both HDAC and GSK-3β. VPA could be used as a novel therapy for the prevention of neurocognitive deficits resulting from cranial irradiation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1457. doi:1538-7445.AM2012-1457
Abstract 1470: Enhancing radiation therapy by simultaneous inhibition of thioredoxin- and glutathione-dependent metabolism
Authors: Rodman Samuel N. , Zhu Yueming , Ronnfeldt Tyler J. , Wilke Werner W. , Allen Bryan G. , Spitz Douglas R. , Fath Melissa A.
Published: August 2012

Cancer cells have been shown to be in a constant state of metabolic oxidative stress, concurrent with an elevated level of reactive oxygen species (ROS). In order to facilitate survival in the face of increased steady-sate levels of ROS, cancer cells rely on glutathione (GSH) and thioredoxin (Trx) dependent metabolism. We have recently demonstrated that the simultaneous inhibition of GSH using Buthionine sulphoximine [(BSO), a GHS synthesis inhibitor] and thioredoxin reductase using auronofin [(Au), a thioredoxin reductase inhibitor] effectively chemo-radio-sensitized lung cancer cells via a mechanism involving oxidative stress. In this work we extend this observation to demonstrate that Au 2 mg/kg and BSO 450 mg/kg, given prior to ionizing radiation (6 Gy x 2 doses) can significantly delay tumor growth rate for mice treated with radiation alone in H292 lung cancer xenografts. In addition, we demonstrate through clonogenic survival assays that the combination of Au (250-500 nM) and BSO (100 μM) radio-sensitizes two breast cancer cell lines in vitro, and more importantly the combination of Au and BSO given by intraperitoneal injection prior to radiation decreases the percent of breast cancer stem/progenitor cells in vivo. The rate limiting substrate for GSH synthesis is cysteine, whose level is controlled by the xc- cystine/glutamate antiporter. Sulfasazine (SSZ) has been shown to be a potent inhibitor of the xc- cystine/glutamate antiporter. We demonstrate that SSZ (0.1-0.5 mM) decreases total GSH (up to 90%) levels in a dose dependent manner in both Mia PaCa-2 and PANC-1 human pancreatic cell lines. The combination of Au (250 nM for 3 hours) with SSZ (0.2 mM for 24 hours) demonstrates an 80% and 30% decrease in clonogenic cell survival in MiaPaCa-2 and PANC-1 pancreatic cells that is inhibited by treatment with the thiol antioxidant, 15 mM N-acetylcysteine. These results indicate that inhibition of hydroperoxide metabolism using pharmacologically relevant agents to simultaneously disrupt GSH and Trx system, can sensitize multiple cancer cell lines to radiation. These results support the hypothesis that standard of care radiotherapy protocols could be enhanced using SSZ, Au, and/or BSO. Supported by The Iowa Center for Research by Undergraduates, R21CA139182, R01CA133114 and a Breast Cancer Research Group Seed Grand from the Holden Comprehensive Cancer Center.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1470. doi:1538-7445.AM2012-1470
Abstract 1477: Tumor metastasis is modulated by tissue stiffness in MMTV-PyMT breast cancer model
Authors: Yu Hongmei , Yui Yoshihiro , Weaver Valerie
Published: August 2012

Tumor metastasis is the major cause of morbidity and mortality from breast cancer, yet there are no effective management strategies and treatments for metastatic breast cancer. These challenges urge us to have a better understanding of tumor metastasis. Factors in the host microenvironment, including stromal cells, cytokines, and non-cellular extracellular matrix (ECM), are known playing important roles on the dynamic process of tumor metastasis. Our and other recent studies have shown breast tumor progression is associated with ECM remodeling, increased collagen cross-linking and tissue stiffening. Tissue stiffening, in particular, promotes tumor cell invasion in MMTV-Her2/Neu mouse model by enhancing the cross talk between the focal adhesion and oncogenic signaling 1. However, ECM is involved in many steps of tumor metastasis, we do not know explicitly if ECM and tissue stiffness would affect the final tumor metastasis, if so how. We answered our questions by investigating the effects of altered tissue stiffness on the lung metastasis in the MMTV-PyMT mouse model for breast cancer as MMTV-PyMT mice develop lung metastasis with 100% efficiency. We inhibited Lysyl oxidase mediated collagen I crosslinking (beta-aminopropion, BAPN 1) in MMTV-PyMT mice at different ages, measured mammary tissue stiffness with high-resolution tissue diagnostic probe, and examined the lung metastasis. We found that there was a close correlation between tissue stiffness and lung metastasis and that preventing tissue stiffening reduced lung metastasis in PyMT model without affecting primary tumor growth. In addition, we found this reduced lung metastasis was correlated with fewer circulating tumor cells. Further studies showed that BAPN inhibited tumors were less hypoxic and that the tumor cells were less migratory than their corresponding controls. These results suggest that increased collagen crosslinking and tissue stiffness contribute to breast tumor metastasis by facilitating tumor cell migration and intravasation processes. A stiffer tissue and ECM not only modulate the capability of tumor cells to migrate but also affect the substrates on which tumor cells migrate. These two major effects of tissue stiffening make tumor cells succeed in intravasation, which is required for their subsequent lung colonization. We are now investigating the underlying molecular and biomechanical mechanisms involved in this specific situation. These studies, together with our previous work on MMTV-Her2/Neu model 1, show that tissue stiffness modulates multiple stages of breast cancer metastasis and will help us to develop novel strategies of managing metastatic breast caners. (Support by DOD.WX81XWH-05-1-0330, NIH/NCI RFA-CA-09-009)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1477. doi:1538-7445.AM2012-1477
Abstract 1501: Direct interaction between human pancreatic cancer stem cells and stromal cells remodels extracellular matrix formation for cancer stem cell niche
Authors: Hori Yuichi , Shimizu Kazuya , Chiba Sachie
Published: August 2012

Human pancreatic ductal adenocarcinomas consist of highly heterogeneous tumor cells that form tumor microenvironment cooperatively with stromal cells. Pancreatic cancer stem cells are reported to play important roles in chemotherapy and radiotherapy resistance. However, little is known about the microenvironment of pancreatic cancer stem cells. To investigate the microenvironment of pancreatic cancer stem cells with stromal cells, we isolated and characterized a novel subpopulation of pancreatic cancer stem cells, tentatively named KMC cells, from seven disseminated pancreatic ductal adenocarcinoma patients. KMC cells required direct cell-cell contacts to stromal cells for their clonogenic growth. KMC cells had self-renewal capacity and in vivo tumorigenicity. In vitro experiments demonstrated that stromal cells induced extracellular matrix (ECM) formation with thin filament structures and KMC cells changed the thin filament structures to basic lamina-like thick and bundled filament structures where laminin proteins were enriched. Moreover, KMC cells induced mRNA expression of laminin-5α and collagen type-IV in stromal cells, major components of basic lamina, but reduced mRNA expression of collagen type-I, collagen type-III, and fibronectin-I in stromal cells, major components of ECM. Our findings demonstrated that pancreatic cancer stem cells have the potential to form their microenvironment with basic lamina-like structures cooperatively with stromal cells, suggesting that targeting KMC cells and KMC cell-induced basic lamina-like structures in cancer therapy may improve prognosis of disseminated pancreatic ductal adenocarcinoma patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1501. doi:1538-7445.AM2012-1501
Abstract 1503: Cancer testis antigen SPANXB2 and prostate cancer progression: Human prostate stroma promotes SPANXB2 expression
Authors: Li Hangwen , krou Ericka Diallo , Ressler Steven , Sreekumar Arun , Ayala Gustavo , Rowley David , Palapattu Ganesh
Published: August 2012

A critical problem in prostate cancer is our inability to reliably distinguish indolent from aggressive disease. Recent evidence has implicated a class of genes, termed Cancer Testis Antigens (CTA) that uniquely expressed on malignant tissue, in cancer progression. CTA SPANXB2 was reported to be associated with aggressive and metastasis of melanoma and other cancers. The role of SPANXB2 in prostate cancer is still uncertain. In preliminary studies, we observed that the CTA SPANXB2 is up-regulated in mRNA level in metastatic prostate cancer xenograft models (PC3 cells injected in mouse dorsal prostate with Matrigel). Compared with other injection sites, mouse dorsal prostate enriched prostate stroma. Therefore, we further tested whether prostate stroma is the key factor to influence SPANXB2 expression and enhance the metastasis potential of prostate cancer cells. We validated this through an in vitro epithelial-stroma interaction models: GFP labeled PC3 cells were placed on the top of human prostate stromal cells (HPS-19I); two days later PC3-GFP cells were isolated through flow cytometry with high purity (> 99%). By real time PCR, the expression level of SPANXB2 in these purified PC3-GFP cells was found to be upregulated up to 10 folds. We also tested DU145 and LNCaP in this same model, and similar results were obtained. We further examined the migration and invasion ability of these cells and found that stromal exposed cells gained an enhanced ability to migrate and invade. Interestingly, we also observed that the stem cells marker, CD24 was highly up -regulated up to 6 folds in PC3 cells after co-culture with HPS-19I. In addition, we treated PC3 cells with TGF-β1 and TGF-β2, and noted that SPANXB2 and CD24 were significantly increased in PC3 cells after 24 hours treatment with TGF-β2. Our results reveal that i) the interaction between human prostate stromal cells and prostate cancer cells promote CTA-SPANXB2 and CD24 expression in prostate cancer cells, ii) these interactions further enhance the migration and invasion ability of prostate cancer cells and iii) TGF-β2 may regulate SPANXB expression relevant cells. These data provide rationale for studying SPANXB2 in stromal-epithelial interactions and may be potentially used to pinpoint druggable targets that drive metastasis and that distinguish indolent from aggressive prostate cancer. Keywords: Cancer testis antigen, SPANXB2, Prostate cancer, Metastasis, Stoma

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1503. doi:1538-7445.AM2012-1503
Abstract 1504: Dual effect of MMP-9 and its fibronectin-like domain in tumor growth and invasion
Authors: Dayer Cynthia , Fusco Carlo , Le-Bitoux Marie-Aude , Stamenkovic Ivan
Published: August 2012

Tumors are often compared to wounds that do not heal, where the crosstalk between tumor cells and their surrounding stroma is crucial at all stages of development from the initial primary growth to metastasis. Similar to wound healing, fibroblasts in the tumor stroma differentiate into myofibroblasts, also referred to as “cancer-associated fibroblasts” (CAFs), primarily, but not exclusively, in response to transforming growth factor-β (TGF-β). Myofibroblasts in turn enhance tumor progression by remodeling the stroma. Among molecules implicated in stromal remodeling, matrix metalloproteinases (MMPs), and MMP-9 in particular, play a prominent role. However, the mechanisms that regulate MMP-9 activation and function remain poorly understood. Recent evidence indicates that tumor cell surface association of MMP-9 is an important event in its activation, and more generally in tumor growth and invasion. Based on these observations, we addressed the potential association of MMP-9 activity with cell-surface recruitment on human fibroblasts. We show for the first time that recruitment of MMP-9 to the MRC5 fibroblast cell surface occurs through the fibronectin-like (FN) domain, found only in MMP-9 and MMP-2. Functional assays suggest that the active form of MMP-9 triggers α-smooth muscle actin (αSMA) expression in resting fibroblasts that reflects myofibroblast differentiation, possibly through TGF-β activation. Preliminary xenograft experiments using HT1080 fibrosarcoma or MDA-MD231 breast adenocarcinoma cells stably expressing the FN domain of MMP-9 in NOD/SCID mice revealed decreased primary tumor growth suggesting that the FN domain alone can displace MMP-9 proteolytic activity from the cell surface. However, in the context of metastasis, expression of the FN domain by these same tumor cells dramatically increases their metastatic proclivity whereas expression of wt MMP-9 either promotes no change or actually reduces the number of metastases. These observations suggest a dual role of MMP-9 and its FN domain in primary tumor growth and metastasis, illustrating protective effects of MMPs in tumor progression and invasion.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1504. doi:1538-7445.AM2012-1504