bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 4960: Circulating miRNAs as noninvasive biomarkers in esophageal adenocarcinoma patients
Authors: Song Jee Hoon , Cheng Yulan , Yang Jian , Wu Wenjing , Mori Yuriko , Olaru Alexandru V. , Bootwalla Moiz , Sharpf Robert , Meltzer Stephen J.
Published: June 2012

Esophageal adenocarcinoma (EAC) is one of the most rapidly increasing cancers in the United States and throughout the developed world. The current primary screening method for EAC is gastrointestinal endoscopy (EGD), and this method is unsuitable and impractical for population-based screening or detection of asymptomatic EAC. Moreover, thus far, only a few reports have described altered miR expression in EAC, none of which were carried out in serum or plasma. We discovered a panel of noninvasive circulating microRNA (miR) biomarkers to promote earlier detection of EAC. We extracted total RNA from serum of each subject and hybridized it to fixed-probe miR microarrays in 12 sera each from EAC patients, subjects with normal EGDs, and 12 matched EAC tissues and normal esophageal tissues from EAC patients. Data was extracted and normalized using Feature Extraction Software 9.3 and GeneSpring software (Agilent) and subsequently analyzed by classification trees, multiple leave-one-out cross-validation, and relative influence plots. We selected the most influential miRs for validation by quantitative RT-PCR assays. Our preliminary miR findings indicate that several miRs show dramatic and significant differences in serum levels between EAC and normal control subjects. An ROC curve assembled based on aggregate data yielded an area under the curve (AUC) = 0.885, with sensitivity = 92% and specificity = 83%. We conclude that a panel consisting of several miRs is likely to discriminate asymptomatic EAC patients from normal subjects, leading to earlier diagnosis and improved prognosis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4960. doi:10.1158/1538-7445.AM2011-4960
Abstract 5036: Activating MEK1(F129L) mutation as a potential mechanism of acquired resistance to MEK inhibition in human cancers carrying the B-RafV600E mutation
Authors: Niu Huifeng , Wang Huisheng , Daouti Sherif , Li Wen-Hui , Wen Yang , Rizzo Christine , Higgins Brian , Packman Kathryn , Rosen Neal , Boylan John F. , Heimbrook David
Published: June 2012

Targeting the Ras/Raf/MEK pathway represents a promising anticancer strategy. The clinical development of MEK inhibitors, similar to other highly selective targeted agents, is expected to have limited durable clinical response due to the emergence of drug acquired resistance. To identify potential mechanisms underlying such resistance, we established MEK inhibitor-resistant clones (HT-29R) from a human colorectal cancer cell line HT-29 harboring the B-Raf V600E mutation. HT-29R are resistant to MEK inhibition under both in vitro and in vivo growth conditions. Drug-induced feedback activation of MEK/ERK and downstream targets were found primarily accountable for the resistance. Moreover, we identified the MEK1(F129L) mutation as a molecular mechanism responsible for pathway activation. In an isogenic cell system and extending into other cancer cell lines, the MEK1(F129L) mutant exhibits higher intrinsic kinase activity than wild type (WT) MEK1, leading to a significant activation of ERK and downstream targets confering resistance to MEK inhibition. The MEK1(F129L) mutation showed stronger binding to c-Raf which suggests an underlying mechanism of the higher kinase activity of the MEK1(F129L). Importantly, the combination of Raf and MEK inhibitors overcame resistance and exhibited greater synergy in HT-29R as compared to HT-29S. This study suggests MEK1 mutation could be a potential mechanism of drug acquired resistance emerging in MEK inhibitor-treated cancer patients and should be monitored in the clinic. Combined inhibition of Raf and MEK represents a potential therapeutic strategy to overcome the resistance.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5036. doi:10.1158/1538-7445.AM2011-5036
Abstract 5038: Why is rapamycin effective against Kaposi sarcoma? An analysis of molecular pathways reveals posttranslational silencing of PTEN
Authors: Dittmer Dirk , Roy Debasmita , Krown Susan E. , Damania Blossom ,   AIDS Malignancy Consortium (AMC)
Published: June 2012

Background: Rapamycin (RAPA) and its derivatives target the mTOR kinase within the PI3K/Akt/mTOR pathway. RAPA induced regression of transplant-associated Kaposi sarcoma (KS), but it is unclear why this cancer and selected others are responsive to mTOR inhibitors, whereas many others are not. KS requires infection with the KS-associated herpesvirus (KSHV). We hypothesized that because of its viral etiology, the PI3K/Akt/mTOR pathway in KS would be activated post-translationally and reversibly rather than by mutation and thus more responsive to small molecule inhibitors.

Material and methods: The AMC conducted a pilot study of RAPA in HIV-associated KS and several partial responses were observed. We used immuno- histochemistry and molecular methods to study the PI3K/Akt/mTOR pathway in sequential biopsies from patients on this trial, as well as in a larger collection of KS biopsies assembled into a TMA, tumor cell lines and tumors from RAPA-treated mice bearing KS xenografts.

Results: Ribosomal protein S6 and Akt were consistently phosphorylated in KS. At the same time PTEN was expressed. We found no evidence for PTEN mutations, rather it was phosphorylated. RAPA inhibited mTORC1 signaling in HIV-KS patients and murine xenografts as determined by loss of S6 phosphorylation. Akt remained consistently activated and we saw no changes in phosphorylation at either the mTORC-independent S308 or mTORC2-dependent T473, i.e. there was no evidence for compensatory upregulation of mTORC2.

Conclusions: Rapamycin inhibits the mTORC1 pathway in HIV-KS. KS can be considered representative of tumors in which PTEN is epigenetically inactivated and which may be most susceptible to mTOR inhibition.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5038. doi:10.1158/1538-7445.AM2011-5038
Abstract 5069: Comprehensive mutational analysis of epidermal growth factor receptor, EML4-ALK, and KRAS identifies four distinct disease entity in never-smoker patients with non-small cell lung cancer
Authors: Kim Hye Ryun , Shim Hyo Sup , Chung Jin-Haeng , Lee Young Joo , Ha Sang-Jun , Kim Se Kyu , Kim Joo Hang , Cho Byoung Chul
Published: June 2012

Purpose: To determine the proportions of major oncogenic mutations and examine the survival in genotype-specific subsets in non-small-cell lung cancer (NSCLC) from never-smokers.

Patients and Methods: We concurrently analyzed mutations in epidermal growth factor receptor (EGFR), EML4-ALK, and KRAS in 229 never-smokers with NSCLC. The ALK rearrangements was identified by using fluorescent in situ hybridization and confirmed by immunohistochemistry. The EGFR (exons 18 to 21) and KRAS (codon 12/13) mutations were determined by direct sequencing.

Results: Of 229 tumors, the frequency of EGFR mutation, ALK rearrangement, KRAS mutation, and wild-type for aforementioned genes (WT/WT/WT) were 48.0%, 8.3%, 3.5%, and 40.2%. All mutations were mutually exclusive. The progression free survival to EGFR tyrosine kinase inhibitors (TKIs) was 12.8, 6.3, 2.1, and 1.6 months in EGFR mutant, WT/WT/WT, KRAS mutant, and EML4-ALK, respectively. In a logistic regression model, the adjusted hazard ratio for the risk of disease progression to EGFR TKIs was 0.59 (95% CI, 0.40 to 0.87; P = .008) for EGFR mutant, 4.58 (95% CI, 2.07 to 10.15; P < .001) for EML4-ALK, 4.23 (95% CI, 1.65 to 10.8; P < .003) for KRAS mutant, respectively. Overall survival was also significantly different among genotypes.

Conclusion: This is the first comprehensive and concurrent analysis of three major oncogenic mutations in the largest-ever cohort of East Asian never-smokers with NSCLC. Since survival outcome is different among genotypes and drugs are now available to target these mutations, genetic profiling is needed to identify genotype-specific subsets and successfully treat them with appropriate kinase inhibitors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5069. doi:10.1158/1538-7445.AM2011-5069
Abstract 5079: A mathematical approach to earlier cancer detection: Using blood biomarker assays to monitor growth of a tumor from a single cell
Authors: Hori Sharon S. , Gambhir Sanjiv S.
Published: June 2012

Early cancer detection may eventually be enabled by a quick, highly sensitive assay to monitor abnormal cancer biomarker levels in blood, followed by a localized imaging scan to visualize tumor burden. To improve screening of high-risk patients prior to imaging, blood assay sensitivity/specificity is being increased and biomarker secretion processes are being studied, but it is not clear which strategies will provide better detection of smaller tumors. To address this, we developed a linear 1-compartment model with 9 parameters to describe plasma biomarker kinetics in relation to the growth of cancer, beginning with a single tumor cell. In this model, plasma biomarker levels are dependent on the number of biomarker-secreting cells (cancerous and healthy), the biomarker secretion rate, the percent of biomarker entering plasma from the interstitium, and the elimination rate of plasma biomarker. To exemplify a realistic case, we based parameter values on ovarian cancer and CA125 secretion because CA125 secretion rates and assay sensitivities are readily available in published literature. Gompertzian tumor growth was modeled using published human ovarian carcinoma growth rates. The model predicted that tumor burden must grow to a volume of (20.4 mm)3 to reach plasma biomarker levels that are greater than in 99.9% of healthy patients; this may require >10 years after the birth of the initial tumor cell. These predictions are consistent with published cancer progression timelines recently uncovered from sequencing of metastatic genome data. Furthermore, by perturbing parameter values over log-orders of magnitude, we identified alternative strategies that could allow detection of <1 mm diameter tumors (Table). Applying this model to other cancers and associated biomarkers may pinpoint characteristics of ideal biomarkers and the assays used to detect them, thereby helping to identify cancers at earlier stages, when they can be more effectively treated.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5079. doi:10.1158/1538-7445.AM2011-5079
Abstract 5134: G-Quadruplex structure formation in the proximal promoter region of the human vascular endothelial growth factor gene
Authors: Agrawal Prashansa , Hatzakis Emmanuel , Guo Kexiao , Yang Danzhou
Published: June 2012

The human vascular endothelial growth factor gene, VEGF, is a key regulator of angiogenesis. It plays an important role in tumor survival, growth and metastasis. It is over-expressed in many types of human cancers including glioma and renal cell carcinoma, ovarian and pancreatic cell carcinomas. The VEGF proximal promoter region contains a poly G/poly C rich tract that is essential for basal and inducible VEGF expression. The guanine-rich (G-rich) strand on this tract is shown to form a specific secondary structure, the G-quadruplex. Here we have elucidated the solution structure of the major intramolecular G-quadruplex formed on the G-rich strand of this region in K+ solution by proton Nuclear Magnetic Resonance (NMR) spectroscopy followed by the structural calculation of the G-quadruplex using Distance Geometry Simulated Annealing (DGSA) module of XPLOR-NIH software. It is inferred that this strand adopts a well-defined parallel-stranded G-quadruplex structure, which contains three G-tetrads stabilized by Hoogsteen hydrogen bonding, as well as three double-chain reversal loops containing 1:4:1 bases, a feature important for the formation of the most thermodynamically stable conformation. The size of the 4-base loop plays a critical role in determining the most favored folded pattern of a G-quadruplex. These 4-base loop residues interact with the residues of the 3’ flanking region of VEGF sequence; also, the 1-base double-chain reversal loop on two edges of the tetrad are very stable, which overall contribute in stabilizing the 1:4:1 conformer. We have found that the two cytosines in this central 4-base loop are involved in hydrogen bonding with the 3’ terminal end residues of VEGF, which is a salient feature as this interaction is sequence-specific and differs from that in other parallel-stranded structures, e.g. c-myc, significantly. These results are also supported by the DMS footprinting results by Guo et al. (2008) which show that the guanines involved in the tetrad formation in this major G-quadruplex loop isomer 1:4:1 are well-protected against DMS methylation. Therefore, the knowledge about the secondary structure of this non B-DNA conformation of the VEGF promoter region is essential for using the G- quadruplex as a target for anticancer drugs, which could be a novel approach to anti-angiogenesis drug discovery in cancer therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5134. doi:10.1158/1538-7445.AM2011-5134
Abstract 5154: Serotonin signaling as a novel target of tumor angiogenesis
Authors: Zamani Ali , Zhai Ling , Roy Anshu M. , Li Rongbao , Qu Zhican , Maxuitenko Yulia Y.
Published: June 2012

Angiogenesis is a well-controlled process that is regulated by multiple factors that are secreted by the cancer cells as well as other cells within the tumor microenvironment. Angiogenesis inhibitors are showing therapeutic efficacy in an increasing number of human cancers. However, in both preclinical and clinical settings, the benefits are transitory and are followed by resistance and a restoration of tumor growth and progression. Therefore, novel anti-angiogenic strategies with complementary mechanisms are needed to maximize efficacy and minimize resistance to current angiogenesis inhibitors. Activation of platelets and blood coagulation frequently occurs in cancer patients. Apart from VEGF, platelets contain several other angiogenic growth factors and inhibitors that are released upon activation and promote tumor neoangiogenesis. Although considerable attention has been focused on platelet peptide growth factors, little is known about the mitogenic effects of nonpeptide platelet products such s serotonin (5-HT), considering that 99% of 5-HT in blood is found in platelets and is released at blood clotting sites. In previous studies, we have shown that endothelial cells express 5-HT receptors and 5-HT has growth stimulatory effcts on multiple types of endothelial cells. We have also demonstrated that 5-HT binds to inhibitory type of G-protein coupled receptors and stimulates the phosphorylation of PYK2/PI3K/AKT/mTOR signaling pathway, the same signaling pathway, which has been activated by most angiogenic factors, including VEGF. In our recent studies, we explored angiogenic promoting activity of 5-HT in the mouse matrigel plug assay (in vivo angiogenesis model system) and antiangiogenic potential of antagonists against 5-HT receptors in xenograft-CAM assay (ex vivo tumor angiogenesis model system). The most importantly, an antagonist against a specific 5-HT receptor demonstrated the synergistic effect in blocking tumor-induced new blood vessel formation when it was applied in combination with Sutent, a FDA approved antiangiogenic drug against VEGF receptor. The results of this study suggest that 5-HT signaling pathway constitute a novel target of tumor angiogenesis in anticancer therapeutic development.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5154. doi:10.1158/1538-7445.AM2011-5154
Abstract 5218: Basigin-2 (EMMPRIN), a prognostic marker, is a dynamic portal of entry into cancer cells
Authors: Ancheta Leonardo R. , Lappi Douglas A.
Published: June 2012

Basigin-2 (EMMPRIN) is a marker for prognosis of several tumor types. With the identification of the internalization of basigin-2 in response to antibody binding, we now further explore the possibility of its use as a dynamic portal of entry for molecules into cancer cells. We also wish to identify a correlation between number of basigin-2 on the cell surface and half maximal effective concentration (EC50) of a targeted toxin by examining eleven tumor cell lines which encompass various tumor types such as breast (MCF-7, BT549), leukemia (K562, HL-60), multiple myeloma (RPMI-8226), neuroblastoma (SH-SY5Y), non-small cell lung (A549, NCI-H23, NCI-H522), and prostate (PC3).

In this investigation, we employed the use of flow cytometry to characterize each cell line according to mean fluorescence as well as to determine the number of basigin-2 molecules expressed on the cell surface through a surface quantification assay. This was visualized by staining with a monoclonal antibody directed to basigin-2 ECD with comparison of results against a standard with known Antibody Binding Capacity (ABC) and standardizing the results into Molecules of Equivalent Soluble Fluorochromes (MESF; Bangs Laboratories, Inc.).

Last year at this meeting we showed the ability of an antibody to basigin-2 ECD to cause internalization of secondary targeted toxins to cause cell death. We now report on the activity of a primary toxin: the ribosome-inactivating protein saporin attached directly to an antibody to basigin-2.

Cytotoxicity assays yielded an EC50 range of 3.5-420 pM while surface quantification assays resulted in expression that ranged from 1-4 million basigin-2 molecules per cell. Cell lines showing potent EC50 values were characterized to have higher surface expression of basign-2 when compared to cell lines with less potent EC50 values.

Preliminary results suggest a correlation between EC50 and basigin-2 surface expression such that more basigin-2 available on the cell surface would facilitate greater opportunity for a primary toxin to bind and enter into the cell and cause cell death. These data suggest the use of basigin-2 as a means to identify an entry system for molecules into cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5218. doi:10.1158/1538-7445.AM2011-5218
Abstract 5225: Quantification of circulating tumor cell aggregates in breast cancer patient blood using an enrichment-free detection method
Authors: Cho Edward H. , Sok Devin , Marrinucci Dena , Luttgen Madelyn , Kolatkar Anand , Yoshioka Craig , Wendel Marco , Matrone Michael A. , Lazar Daniel , Yang Xing , Malchiodi Michael , Lamy Rachelle , Torrey Melissa , Bethel Kelly , Kuhn Peter
Published: June 2012

Circulating tumor cells (CTCs) have been implicated as a potential population of cells that may seed metastasis in cancer patients. In order to characterize and understand this population of cells, an enrichment-free immunofluorescence detection method was developed by our lab. This method take whole patient blood and classifies cells based on cytokeratin (CTCs) and CD45 (WBCs) antibody staining. Using this CTC detection method, a population of cells residing in tumor cell aggregates was observed in blood draws from Stage IV breast cancer patients. It was previously observed in ex vivo mouse experiments that homotypic aggregate formation of tumor cells may increase metastatic efficiency (Glinsky, et al., Cancer Research, 2003). In this work, we seek to determine if a significant proportion of CTCs reside in homotypic aggregates in patient blood by enumerating CTC aggregates from the blood draws of 23 Stage IV breast cancer patients and 16 healthy donor patients. Preliminary analysis measuring associations of CTCs with other nucleated cells found in patient blood draws revealed that ∼43% of cytokeratin-positive (CK+) cells found in breast cancer patient samples localize with either other CK+ or white blood cells (WBCs) versus 14% in healthy donor patient samples. Furthermore, ∼19% of WBCs were found to be associated with either CK+ or other WBCs in breast cancer patient samples versus ∼7% in healthy donor patient samples. Pathological review confirming CK+ cells as CTCs revealed that of the CTCs detected in patient blood after pathological review, ∼2% of CTCs were found as homotypic aggregates versus ∼0.07% in healthy donor samples (p=0.0005). Four breast cancer patients were found to have no CTC aggregates. Two breast cancer patients had significantly higher than average CTC aggregate percentages (∼6% and ∼7%). Patients will continue to be monitored to measure any differences in disease outcome of patients with high incidence of CTC aggregates versus patients with low incidence of CTC aggregates and healthy donors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5225. doi:10.1158/1538-7445.AM2011-5225
Abstract 5287: Non-invasive imaging of tumor cell death using a Hsp90 ligand
Authors: Park Danielle , Don Anthony , Massamiri Tania , Karwa Amol , Warner Beth , Hemenway Christine L. , Naik Arati D. , Kuan Kah-Tiong , Dilda Pierre J. , Wong Jason , Chinen Lori , Dyszlewski Mary , Hogg Philip J.
Published: June 2012

Cell death plays an integral role in physiology, including turnover of cells in the gastrointestinal tract, the menstrual cycle and the immune system. Imbalance of this process is also associated with disease. Excessive cell death is characteristic of vascular disorders, neurodegenerative diseases, myelodysplastic syndromes, ischemia/reperfusion injury and organ transplant rejection, among others.

Cell death also plays a role in the treatment of disease. In cancer for example, most chemotherapeutics, radiation treatments and anti-hormonal agents act by inducing death of cancer cells. Given the prevalence of cell death in normal physiology and disease, non-invasive imaging of this process is likely to have wide application in biological research and ultimately in patient diagnosis and management.

Common to apoptotic and necrotic death cell is eventual loss of plasma membrane integrity. We have developed a small, synthetic organoarsenical compound (4-(N-(S-glutathionylacetyl)amino) phenylarsonous acid) that rapidly accumulates in the cytosol of dying cells, coincident with loss of plasma membrane integrity. The compound is retained in the cytosol predominantly by covalent reaction with the 90-kDa heat shock protein (Hsp90), the most abundant molecular chaperone of the eukaryotic cytoplasm. The organoarsenical was tagged with either optical or radioisotope reporting groups to image cell death in cultured cells and in murine tumors ex vivo and in situ. Tumor cell death in mice was non-invasively imaged by SPECT/CT using an 111In-tagged compound.

This versatile compound has the advantage of chemical stability, exquisite selectivity for dying cells and versatility with respect to the reporting group. The nature and abundance of its cytosolic target, Hsp90, also bodes well for its suitability for the imaging of cell death in most experimental settings.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5287. doi:10.1158/1538-7445.AM2011-5287
Abstract 5295: Near-infrared fluorescence in vivo tumor imaging using SNAP-tag technology
Authors: Gong Haibiao , Kovar Joy , Zhang Aihua , Correa Ivan R. , Xu Ming-Qun , Olive Michael
Published: June 2012

The SNAP-tag is a small protein derived from the human DNA repair protein O6-alkylguanine-DNA-alkyltransferase (hAGT). It reacts with fluorescent dye conjugated benzylguanine (BG) substrate, leading to covalent labeling of the fluorescent dye on the SNAP-tag®. This property makes the SNAP-tag a valuable tool for fluorescence imaging. In this study, we extended the SNAP-tag technology to near-infrared (NIR) fluorescence imaging using IRDye® 800CW conjugated BG substrate (BG-800). Compared to the visible spectrum, fluorescence in the NIR spectrum has the advantage of low light absorption and reduced autofluorescence, which is highly desirable for in vivo imaging. We created HEK293, MDA-MB-231, SK-OV-3 and SK-BR-3 cells stably expressing SNAP-ADRB2 fusion protein. The ADRB2 potion of the protein directs the localization of the protein to the cell membrane. The expression of SNAP-ADRB2 was confirmed by the reaction between BG-800 substrate and the cell lysate. Microscopic examination confirmed that SNAP-ADRB2 was localized on the cell membrane. The signal intensity of the stable cells after reaction with the substrate BG-800 was dependent on the BG-800 concentration. In vivo imaging study showed that BG-800 could visualize xenograft tumors established with SNAP-ADRB2 overexpressing SK-OV-3 cells. These results demonstrated that the application of SNAP-tag technology could be extended to in vivo imaging when combined with NIR fluorescent fluorophores.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5295. doi:10.1158/1538-7445.AM2011-5295
Abstract 5297: Dual-modality imaging of hepatocellular carcinoma
Authors: Corn David , Jesberger Jack , Kolthammer Jeffrey , Flask Christopher , Lee Zhenghong
Published: June 2012

Choline compounds are linked to malignancy since elevation of the intensity of choline peak reflects increased biosynthesis of membrane phospholipids and can be a marker for cellular proliferation. Positron Emission Tomography (PET) images an injected tracer dose (nM∼pM) of [11C]-choline while Proton MR Spectroscopy (1H MRS) can characterize endogenous choline-containing compounds usually in the mM range. There have been studies on brain and prostate cancers with both imaging modalities although correlation between the results from PET and MRS is inconsistent. The transient radiolabeled choline metabolism measured by PET is different from the relative steady total choline contents measured by MRS. However, it begs the question of whether the two imaging modalities are measuring the same metabolic pathways of choline in cancer. For primary Hepatocellular Carcinoma (HCC), there have been [11C]-choline PET studies, both pre-clinical and clinical, showing focal uptake. Likewise, there have been 1H-MRS studies of choline with animals and humans showing significantly high choline levels in HCC. So far, there is no comparison study reported to link the two measurements in HCC.

This study was conducted with a woodchuck model of hepatitis viral infection-induced HCC, which is regarded as a naturally occurring animal model of human HCC with similar pathology and clinical behavior. The original objective of the study was to examine the effects of animals being fed and fasted on PET scans using [11C]-choline. MRI and MRS were added and performed immediately before PET imaging. Experiments were first performed with animals at the fed state using a 4T MR scanner with a human head coil. Dynamic PET images were then generated from a nearby clinical PET/CT scanner right after, spanning 50 minutes starting from [11C]-choline injection. Time-activity curves and tracer contrast uptake between focal uptake in HCC and that in the surrounding hepatic tissues were calculated in liver regions. The same animals were scanned again four days later following the exact same procedure, except that the animals were fasted over night. The results from PET imaging with [11C]-choline showed that the dietary state of fed or fast had little impact on radio-choline uptake in HCC while the results from 1H MRS of choline found similar choline/lipids ratios in HCC regardless of whether the animal was fed or fasted. These results are very promising for correlating the two measurements although further experiments are needed to confirm that the two imaging modalities are measuring related lipid metabolic pathways in HCC involving choline. This work is supported in part by NCI grants R01 CA095307 and U24 CA110943.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5297. doi:10.1158/1538-7445.AM2011-5297
Abstract 5307: VEGF downregulation by HSP90 inhibitor NVP-AUY922 visualized with 89Zr-bevacizumab PET in triple negative breast cancer (TNBC)
Authors: van Scheltinga Anton Terwisscha , Hooge Marjolijn Lub-de , Kosterink Jos , Timmer-Bosscha Hetty , Akimov Mikhail , de Vries Elisabeth , Schröder Carolien
Published: June 2012

Zirconium-89 (89Zr) labeled bevacizumab visualizes tumor vascular endothelial growth factor (VEGF) excretion in vivo, and can therefore serve as a potential biomarker for targeted drugs affecting VEGF levels. TNBC is more dependent upon alternative routes for their maintenance, such as angiogenesis, than hormone receptor or HER2 positive breast cancer. HSP90 inhibitors are known to impact the angiogenesis pathway via degradation of HSP90 client proteins such as HIF1α and VEGFRs, and in vitro studies have shown that breast cancer cells (including TNBC) are sensitive to these compounds. The aim of this study was to image modulation of VEGF expression in response to HSP90 inhibition with NVP-AUY922, a highly potent non-geldamycin HSP90 inhibitor, in a mouse model with a TNBC xenograft.

Methods: Three groups of animals were used in this study, a control (n = 6), treated (n = 7) and placebo (n = 6) group. Twenty-two days after inoculation of TNBC cell line MDA MB-231, all mice received co-injection of 89Zr-bevacizumab and Indium-111 (111In) labeled IgG as aspecific control. VEGF-PET was performed 144 h after tracer injection. Ex vivo biodistribution studies were performed in the control group after the first scan week, for the treatment and placebo group after the second scan week, which was after 3 weeks of treatment. The control group received no treatment, the treatment and placebo group received respectively 50 mg/kg NVP-AUY922 or vehicle every-third-day (q3d) administrated intraperitoneally. Treatment effect was verified with histological response.

Results: VEGF-PET showed a decreased 89Zr-bevacizumab tumor uptake of 44% (P = 0.0021) after 3 weeks NVP-AUY922 treatment compared to the baseline scan. Placebo treated mice showed no significant difference in bevacizumab uptake. These in vivo imaging data were supported by ex vivo biodistribution data. IgG tumor uptake was in all groups consistent, indicating that there was no influence on tumor perfusion due to the anti-angiogenic treatment. VEGF downregulation in the tumors was shown by immunohistochemistry of VEGF-A.

Conclusion: NPV-AUY922 downregulates VEGF in a TNBC mouse model. VEGF-PET using 89Zr-bevacizumab can be used in vivo to monitor downregulation of VEGF excretion in response to HSP90 inhibition, and can therefore potentially serve as biomarker for early HSP90 inhibition effect in TNBC.

Supported by a grant of the Dutch Cancer Society.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5307. doi:10.1158/1538-7445.AM2011-5307
Abstract 5337: The role of Eya3 as a target of EWS/Fli1 in Ewing's sarcoma
Authors: Robin Tyler , Reaves Lisa , Mckinsey Erin , Jedlicka Paul , Ford Heide
Published: June 2012

Ewing's sarcoma is an aggressive pediatric bone cancer most commonly affecting patients between 10 and 20 years of age. The vast majority of Ewing's sarcomas harbor a characteristic translocation between chromosomes 11 and 22, encoding the EWS/Fli1 fusion protein. Fli1 is an Ets transcription factor with a DNA-binding domain, whereas the EWS portion of the fusion contributes a transcriptional activation domain. EWS/Fli1 acts as a potent oncogenic transcription factor that is critical in the development of Ewing's sarcoma. EWS/Fli1 knockdown and rescue microarray data suggest that Eya3 may be a downstream target of EWS/Fli1, which we have validated using EWS/Fli1 overexpression and knockdown systems. Eya3 is important in DNA repair, and can interact with the Six family of homeoproteins as a bipartite transcription factor. The Six-Eya complex promotes proliferation and survival to facilitate the proper development of many tissues, but these features can also lead to aggressive cancers when re-expressed in adult tissues. We have shown that Eya3 knockdown in the human tumor-derived Ewing's sarcoma cells line, A673, decreases the rate of proliferation of these cells. Additionally Eya3 knockdown sensitizes Ewing's sarcoma cells to chemotherapeutics currently used to treat Ewing's sarcoma: doxorubicin, etoposide, and vincristine. Furthermore, clonal isolates of A673 Eya3 knockdown cells, expressing very low levels of Eya3, morphologically resemble their presumed cell of origin, the mesenchymal stem cell. These data suggest that Eya3 is an important target of EWS/Fli1 that may serve as a clinically significant novel therapeutic target for the treatment of Ewing's sarcoma patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5337. doi:10.1158/1538-7445.AM2011-5337
Abstract 5350: Distinction of childhood soft tissue sarcomas with high metastatic potential by miRNAs
Authors: Herrmann Delia , Armeanu-Ebinger Sorin , Warmann Steven W. , Bonin Michael , Leuschner Ivo , Brücher Björn , Fuchs Jörg , Seitz Guido
Published: June 2012

Background: Advanced stage alveolar (RMA) and embryonal rhabdomyosarcoma (RME) as well as malignant rhabdoid tumor (MRT) have a poor prognosis. Novel treatment approaches based on an improved understanding of metastatic invasion are required. Aberrant microRNA (miRNA) expression is found in cancer progression and metastatic invasion and may help to identify novel targets. The aim of this study was to identify specific miRNA expression patterns in pediatric soft tissue sarcomas.

Methods: We analyzed the expression of 743 miRNAs in 5 RMA, RME, and MRT formalin fixed tissue samples and in the rhabdomyosarcoma (RMS) cell lines Rh30 and RD using an Illumina BeadArray. Differentially expressed miRNAs between RMS and MRT specimens were identified on the basis of the cubic spline algorithm using BeadStudio Software. Selected target miRNAs were transfected with mimic or inhibitor oligonucleotides. Functional analysis was monitored by western blotting, flow cytometry, and migration assays.

Results: Principal component analysis as well as Spearman's rank correlation on the set of differentially expressed miRNAs showed tissue-specific clustering. A review of the literature revealed 23 miRNAs promoting and 46 miRNAs suppressing metastatic invasion. Eight miRNAs regulating migration in both directions were also described.

In our study, metastatic invasion associated miRNAs miR-9* and miR-221 were overexpressed in RMS tissue samples compared to MRT. miR-200c, which inhibits metastatic invasion, was lower expressed in RMS than in MRT. Transient transfection of RMS cells with a miR-200c mimic resulted neither in a reduction of the direct target ZEB1 nor in an increase of the ZEB1-repressed ectopic E-cadherin expression. Migration of RMS cells after induction of miR-200c was not decreased. Furthermore, inhibition of miR-9* and miR-221 in RMS cell lines did not influence migration characteristics.

Conclusions: Pediatric RMS and MRT can be distinguished by their specific miRNA expression pattern. These might also help for an optimized risk stratification of these tumors. A modulation of the metastatic invasion was not possible by the investigated miRNAs. Therefore, regulation of migration seems to be controlled by multiple miRNAs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5350. doi:10.1158/1538-7445.AM2011-5350
Abstract 5351: Prevalence and function of p53 mutations among children with adrenocortical carcinoma (ADCC)
Authors: Wasserman Jonathan D. , Novokmet Ana , Eichler-Jonsson Claudia , Malkin David
Published: June 2012

Adrenocortical carcinoma (ACC) is a rare tumor in children, affecting 0.4 per million children worldwide. Incidence in adults is approximately 5-fold higher and may represent a distinct genetic and biologic entity. Mortality rates among patients with ACC are high and treatment options are limited. Previous studies have suggested that a majority of children who develop ACC possess germline mutations in the p53 tumor suppressor gene. In this study we sought to characterize the prevalence and mutational spectrum of p53 among a large multi-center cohort of children with ACC. We further compared the specific mutations found in these children with mutations found in individuals with the Li-Fraumeni syndrome, a familial cancer predisposition syndrome which is strongly associated with germline p53 mutation.

Among 58 independent pedigrees assessed for p53 mutation, 29 (50%) carried a heterozygous mutation in p53. No mutation was identified more than once among this cohort. This is in contrast to families with the LFS, where 6 “hotspot” mutations are disproportionately over-represented, combined accounting for 20% of patients with identified p53 mutations. Missense mutations were noted in 28/29 individuals, with a single intragenic deletion identified in the remaining individual. Mutations were found predominantly within the DNA-binding domain (26/29 (90%)). One mutation was identified in the trans-activation domain and two in the oligomerization domain.

In the course of this analysis, we identified several novel p53 mutations among children with ACC. These mutations were functionally characterized in vitro based on the ability of mutant p53 to activate transcription of known p53 target genes including those involved in DNA damage repair, cell-cycle arrest and apoptosis. Dominant-negative activity of these mutations was also assessed. Several of the novel mutations demonstrated either full p53 function or partial loss-of-function. The association of these seemingly milder mutations with adrenal tumorigenesis suggests that adrenal tissues may be more sensitive to partial decrease in p53 function than other LFS-affected tissues and that other predisposing or disease-modifying genetic alterations may exist to propel these cells towards a transformed fate.

Further efforts to identify disease modifying loci, as well as pathogenic loci in children with wild-type p53 genes are underway via genome-wide analysis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5351. doi:10.1158/1538-7445.AM2011-5351
Abstract 5415: Preclinical evaluation of telomerase-specific oncolytic virotherapy for human bone and soft tissue sarcomas
Authors: Sasaki Tsuyoshi , Tazawa Hiroshi , Hasei Jo , Kunisada Toshiyuki , Yoshida Aki , Morimoto Yuki , Urata Yasuo , Nouso Kazuhiro , Ozaki Toshifumi , Fujiwara Toshiyoshi
Published: June 2012

Purpose: Bone and soft tissue sarcomas frequently occur in young children and show aggressive progression, resistance to conventional chemotherapy and poor prognosis, indicating a requirement for novel antitumor therapy to improve the clinical outcome. Tumor-specific replication-selective oncolytic virotherapy is a promising antitumor therapy for induction of cell death in tumor, but not of normal, cells. We previously developed an oncolytic adenovirus, OBP-301, that kills human epithelial malignant cells in a telomerase-dependent manner. Recent evidence suggests that non-epithelial malignant cells, which have low telomerase activity, maintain telomere length through alternative lengthening of telomeres (ALT). However, it remains unclear if OBP-301 is cytopathic for non-epithelial malignant cells. Here, we evaluated the antitumor effect of OBP-301 on human bone and soft tissue sarcoma cells.

Experimental Design: The cytopathic activity of OBP-301, coxsackie and adenovirus receptor (CAR) expression, and telomerase activity were examined in 10 bones (OST, U2OS, HOS, HuO9, MNNG/HOS, SaOS-2, NOS-2, NOS-10, NDCS-1 and OUMS-27) and in 4 soft tissue (CCS, NMS-2, SYO-1 and NMFH-1) sarcoma cell lines. OBP-301 antitumor effects were assessed using orthotopic tumor xenograft models. The fiber-modified-OBP-301, (OBP-405), was used to confirm an antitumor effect on OBP-301-resistant sarcomas.

Results: OBP-301 was cytopathic for 12 sarcoma cell lines but not for the non-CAR-expressing OUMS-27 and NMFH-1 cells. Sensitivity to OBP-301 was dependent on CAR expression, not on telomerase activity. ALT-type sarcomas were also sensitive to OBP-301 because of upregulation of human telomerase reverse transcriptase (hTERT) mRNA following virus infection. Intratumoral injection of OBP-301 significantly suppressed the growth of OST and SYO-1 tumors. Furthermore, fiber-modified OBP-405 showed antitumor effects on OBP-301-resistant OUMS-27 and NMFH-1 cells.

Conclusions: We showed that OBP-301 has antitumor effects on both non-ALT-type and ALT-type sarcoma cells through upregulation of human telomerase reverse transcriptase mRNA. Furthermore, coxsackie and adenovirus receptor-negative sarcoma cells were efficiently killed by fiber-modified OBP-301-derived-OBP-405 through virus-integrin binding. A telomerase-specific oncolytic adenovirus is a promising antitumor reagent for the treatment of bone and soft tissue sarcomas.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5415. doi:10.1158/1538-7445.AM2011-5415
Abstract 5416: The low-molecular-weight compound MS-444 selectively targets cancer cells via inhibition of the mRNA stability factor HuR
Authors: Blanco Fernando F. , Meisner Nicole-Claudia , Dixon Dan A.
Published: June 2012

Colorectal cancer (CRC) is the third most common cancer among American adults and a leading cause of cancer-related mortality. The initiation and progression of colorectal tumorigenesis is characterized by genetic alterations that promote aberrant expression of oncogenic and tumor-promoting factors. In normal cells, the mRNAs of these inflammation- and cancer-associated genes are targeted for rapid decay through AU-rich elements (ARE) present in the mRNA 3’UTR. However, loss of ARE-mediated mRNA decay is a characteristic feature contributing to pathogenic gene overexpression in colorectal cancer. Our prior work identified enhanced expression of the RNA-binding protein HuR to occur during colon tumorigenesis and HuR overexpression is correlated with poor clinical prognosis. In this capacity, HuR acts as a mRNA stability factor by promoting ARE-containing mRNA stabilization. Therefore, HuR has emerged as a novel pharmacological target with potential selectivity for cancer cells. This was examined by treating HuR-overexpressing CRC cell lines HCT116, SW480, RKO, and HT-29 with the small molecule inhibitor of HuR MS-444. Growth inhibition was observed in all CRC lines with IC50 values of 7-12 µM and cancer cell selectivity was observed with 4- to 5-fold increased MS-444 IC50 in non-transformed intestinal and colonic epithelial cells. HuR is predominantly nuclear in non-transformed cells, whereas in CRC cells aberrant cytoplasmic HuR trafficking is observed indicating that cytoplasmic localization is a necessary component for HuR-mediated ARE-mRNA stabilization and cancer cell survival. In HCT116 cells treated with MS-444, complete inhibition of cytoplasmic HuR was observed along with induction of apoptosis. Similarly, long-term siRNA-mediated knockdown of HuR in HCT116 cells resulted in cellular apoptosis, and cells with attenuated levels of HuR exhibited a 5-fold higher sensitivity to MS-444 treatment. Expression profiling revealed increased expression of many pro-apoptotic proteins to be present in colon cancer cells resulting from MS-444 treatment. The expression of Fas ligand, a TNF superfamily member, is significantly increased, accompanied by elevated expression of caspase 8 and cell death effectors such as Bax and Bid. These results indicate that MS-444 treatment triggers a Fas-dependent signaling cascade mediated through cellular caspases, thereby resulting in cell death. Taken together, these findings indicate that small molecule-based inhibition of HuR results in selective cancer cell death while also indicating that overexpression of HuR is a necessary component for colorectal tumor cell survival.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5416. doi:10.1158/1538-7445.AM2011-5416