bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 4758: Self-assembled superparamagnetic iron oxide nanoparticles for targeted cancer therapy
Authors: Sailaja G. S. , Gondi Christopher S. , Bhoopathi Praveen , Gorantla Bharathi , Rao Jasti S.
Published: August 2012

Surface engineered iron oxide nanoparticles offer greater potential for targeted gene therapy as compared to many of the current treatment modalities for cancer. The intrinsic superparamagnetism of iron oxide nanoparticles along with a bio-inspired coating to circumvent the physiological and cellular barriers suggests their usefulness as an efficient non-invasive therapeutic option to invoke the desired response at the tumor site. In the present study, a novel functionalized iron oxide nanoparticle based polyplex system that explores the greater potentials of self-assembly together with magnetic targeting is employed for “smart targeting” and to improve therapeutic index. Poly (L-glutamic acid) functionalized iron oxide nanoparticles (Feg) were synthesized and complexed with plasmid DNA containing the gene of interest in the presence of carboxymethyl chitosan (CMCS). The preliminary characterization of the nanoparticles was performed by X-ray diffraction and FT-IR analysis. The formation and the internalization of Feg-CMCS-DNA polyplex occurred irrespective of the type of DNA as illustrated by gel retardation assay and Prussian blue staining, respectively. The Feg-CMCS nanoparticles, when conjugated with secreted protein acidic and rich in cysteine (SPARC)-overexpressing plasmid, showed excellent cytocompatibility (evident from MTT assay, morphology and organization of cytoskeleton) with comparable in vitro biofunctionality (illustrated by western blot analysis) as that of a commonly used transfection agent. The supramolecular assembly of the (Feg-CMCS-SPARC) polyplex system was manifested by scanning and transmission electron micrographs. The mechanism of internalization of the polyplex system and the role of magnetic field in enhancing the internalization were observed by transmission electron microscopy. Further, Feg-CMCS-SPARC polyplex transfection resulted in significant inhibition of in vitro tumor angiogenesis. This study highlights the superior efficacy of Feg-CMCS-SPARC self-assembled polyplex system for use as a localized therapeutic drug in vivo at the tumor site.

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 4758. doi:1538-7445.AM2012-4758
Abstract 476: The effects of the synthetic triterpenoid acetylenic tricyclic bis-(cyano enone) on cell migration and epithelial-to-mesenchymal transition
Authors: Chan Eddie , Guglielmo John Di
Published: August 2012

During metastasis, epithelial tumor cells undergo epithelial to mesenchymal transition (EMT) allowing them to migrate to distant organs to establish secondary tumors. Cell migration is initiated by the asymmetrical localization of polarity proteins towards the leading edge. This stimulates the reorganization and polymerization of the microtubule and actin cytoskeletons, which form protrusions in the plasma membrane to drive the cell forwards. Metastasis accounts for over 90% of cancer related deaths, thus a reduction in cancer mortality will require therapies aimed at preventing or delaying the events of metastasis. Our lab has identified the synthetic triterpenoid, CDDO-Im, as a potent inhibitor of cell migration by inhibiting the polymerization of branched actin and disrupting the organization of the microtubule network (To et al., J Biol Chem. 2008, 2010). Recently, TBE-31 has been developed, which is a smaller 3-ring compound that contains the same active functional groups as CDDO-Im. Here we assessed the effects of TBE-31 on cell migration and EMT. TBE-31 was found to displace the polarity proteins from the leading edge of migrating cells and induce multiple cell protrusions. The microtubule network was also observed to be disorganized and the rate of polymerization for both tubulin and actin were lowered in the presence of TBE-31. These effects are believed to allow submicromolar concentrations TBE-31 to inhibit cell migration by as much as 60%. Finally, the reorganization of actin and formation of stress fibers normally associated with EMT was also inhibited by TBE-31 in A549 tumor cells. We are now confirming our results in a panel of lung tumor cell lines. In conclusion, TBE-31 disrupts the cytoskeleton and inhibits cell migration and preliminary data suggest TBE-31 may also hinder EMT. Further research will be needed to determine the overall impact these effects have on the progression of metastasis.

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 476. doi:1538-7445.AM2012-476
Abstract 4762: Effect of the phytochemical crinumaquine on prostate and prostate cancer cell lines
Authors: Liu Run-hui , Jin Huizi , Ke Xi-Song , Qu Yi , Hellem Margrete R. , Rostad Kari , Oyan Anne Margrete , Kalland Karl H. , Zhang Wei-Dong
Published: August 2012

We have published a new prostate cell culture model in which benign, immortalized prostate epithelial EP156T cells gave rise to progeny cells with a stepwise accumulation of defined malignant features. In a screen of a panel of phytochemicals using this cell culture model, the small molecular compound crinumaquine exerted differential effects on benign prostate cancer cells compared with progeny cells with accumulated malignant features. The differential effect included proliferation and induction of a striking phenotype of the more malignant cells. The induced phenotype comprised extensive membrane protrusions and cell contacts between neighbouring cells following crinumaquine treatment for 2 - 4 days. Conditioned medium from the changed cultures induced a similar phenotype within hours in non-treated cells. Genome-wide gene expression analysis using the Agilent 44k oligoarray platform revealed that crinumaquine treatment reduced expression of multiple genes involved in cell division and strongly induced several genes involved in apoptosis induction. Furthermore, crinumaquine treatment induced multiple genes of cell adhesion modules such as gap junctions, adherens junctions and desmosomes. These findings have motivated further examinations of the ability of crinumaquine to compromise epithelial to mesenchymal plasticity and its potential in the treatment of prostate cancer.

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 4762. doi:1538-7445.AM2012-4762
Abstract 477: Bcl-2 suppresses cell spreading, adhesion and migration in non-small cell lung cancer cells
Authors: Halim Hasseri , Chanvorachote Pithi
Published: August 2012

Bcl-2 is mainly thought to regulate cell apoptosis. However, little is known about its regulation associated with cell metastasis. Here, we demonstrate that Bcl-2 plays an important role in the cell spreading, adhesion and migration of non-small cell lung cancer cells. To study the role of Bcl-2, mutant cell lines exhibiting stably up-regulated and down-regulated Bcl-2 were generated using Bcl-2 plasmid and RNA interference. As compared to control H460 cells, Bcl-2 overexpressed cells exhibited significantly decreased cell spreading, adhesion and migration. Consistent with these results, the loss of Bcl-2 in Bcl-2 knockdown cells increased cell spreading, adhesion and migration. The morphology characteristics study has shown that Bcl-2 increased mesenchymal-epithelial transition phenotype whereas the loss of Bcl-2 increased epithelial-mesenchymal transition phenotype. The increase of fluorescent intensity of phalloidin staining in Bcl-2 overexpressed cells suggesting actin polymerization might be responsible in the supression of cell spreading, adhesion and migration. This result may explain why Bcl-2 has been suggested as a prognostic factor for survival in lung cancer 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 477. doi:1538-7445.AM2012-477
Abstract 4773: Synergistic effects of chitosan and docosahexanoic acid on osteopontin expression and secretion in an ovarian cancer cell line, SKOV-3
Authors: Williams Ebonee , Otenyo Phane , Carr Domonique , Hicks Antoine , Macaulay Daniel , Peterson Deforest , Stone Julia , Carson Laura , Regisford Gloria C.
Published: August 2012

Current treatment for the deadliest gynecological disease, ovarian cancer, is surgical debulking followed by chemotherapy or radiotherapy, but reoccurrence is still significantly high. Hence, there is a need for alternative treatments, and more specifically a natural therapeutic product. Recent studies have shown that natural products, such as chitosan and omega-3 fatty acids, inhibit the proliferation of cancer cells. Osteopontin (OPN), a cell surface and secretory glycoprotein, has been implicated as an important biomarker for ovarian cancer. Therefore, the objective of this study was to determine the effect of chitosan and DHA on OPN secretion and expression levels in an ovarian cancer cell line, SKOV-3 cells. We hypothesized that chitosan and DHA will decrease OPN expression in a dose-dependent manner. To test our hypothesis, SKOV-3 cells were treated with (a) 0 ng/mL, (b) 1% acetic acid; (c) 250 ng/mL of chitosan, (d) 100 µM of DHA, (e) 250 ng/mL of chitosan + 100 µM of DHA for 24 and 48 hours. Western Blot analysis and immunocytochemistry were performed to observe the expression and localization of OPN, while an ELISA was used to determine OPN secretion. Quantitative RT-PCR was also performed to determine OPN mRNA expression in the treated cells. Osteopontin (OPN) protein was localized on the surface of SKOV-3 cells and its expression decreased in both chitosan and DHA-treated cells. Furthermore in cells treated with both chitosan and DHA, there was an even greater decrease in OPN expression. The synergistic effects of chitosan and DHA suggest that these natural products may serve as potential natural treatment for ovarian cancer.

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 4773. doi:1538-7445.AM2012-4773
Abstract 4776: From in-silico screening to anti-cancer activity: The discovery of a potent inhibitor targeting the JNK-JIP interaction
Authors: Kaoud Tamer S. , Yan Chunli , Tseng Chun-Chia , Jose Jiney , Devkota Ashwini K. , Taliaferro Juliana , Ren Pengyu , Dalby Kevin
Published: August 2012

The JNK signaling pathway is related to the pathogenesis of several diseases, including cancer (JNK2 selective inhibitors have been reported as potential suppressor of breast cancer cell migration). The JNK-JIP interaction represents an attractive target for the selective inhibition of JNK-mediated signaling. Herein, we applied a Hybrid Structure-Based Virtual-Screening (VS) workflow based on a combination of 3D shape and electrostatic similarity with GOLD (Genetic Optimization in Ligand Docking) and FRED (Fast Rigid Exhaustive Docking) docking screening techniques to discover novel scaffolds for small ATP-Independent JNK inhibitor targeting the JNK-JIP interaction. The starting point for the VS here was BI78-D3, which has been reported as the first inhibitor targeting JNK-JIP interaction. Out of 750 compounds representing the highest ranked by VS of NCI (National Cancer Institute) Diversity Set (∼250,000 compounds), 352 were tested by in-vitro cell-free kinase assay. The Ability of the used VS protocol to identify selective JNK inhibitors has been tested by screening those 352 compounds against five different kinases. The two tested atypical kinases (eEF2K and TrpM7) which has the least structure similarity with MAP kinases showed very limited inhibition if compared to JNK1 and JNK2, surprisingly, ERK2 and P38-alpha, the two structurally similar to JNK, showed similar results to the alpha kinases. This has been confirmed by an enrichment experiment that has been done using 350 compounds that randomly selected from the same library without employment of virtual screening, these compounds showed very similar inhibition pattern to both JNK and TrpM7 due to the loss of JNK selectivity that established by employment of VS. To validate the efficiency of the used VS protocol to identify inhibitors that bind the JIP-JNK binding site, we developed a displacement assay using FITC (Fluorescein-isothiocyanate) labeled-JIP peptide. Most of the compounds that inhibited JNK kinase activity more than 50% were able to decrease binding of the labeled JIP-peptide to JNK, suggesting the successful targeting of the substrate-binding site of JNK by the identified inhibitors. In summary, the used VS protocol identified novel scaffolds for JNK selective small ATP-Independent inhibitors targeting the JNK-JIP interaction. These compounds will be potential candidates as inhibitors of breast cancer cell migration.

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 4776. doi:1538-7445.AM2012-4776
Abstract 4789: Stable isotope labeling with amino acids in cell culture (SILAC)-based quantitative proteomics study of a thyroid hormone-regulated secretome in human hepatoma cells
Authors: Chen Cheng Yi , Chung I-Hsiao , Lin Kwang-Huei
Published: August 2012

The thyroid hormone, 3, 3′, 5-triiodo-L-thyronine (T3), regulates cell growth, development, differentiation, and metabolism via interactions with thyroid hormone receptors (TR). However, the secreted proteins that are regulated by T3 are yet to be characterized. In this study, we used the quantitative proteomic approach of stable isotope labeling with amino acids in cell culture (SILAC) coupled with nano-LC-MS/MS performed on a LTQ-Orbitrap instrument to identify and characterize the T3-regulated proteins secreted in human hepatocellular carcinoma cell lines overexpressing TRα1 (HepG2-TRα1). In total, 1742 and 1714 proteins were identified and quantified, respectively, in three independent experiments. Among these, 61 upregulated two-fold and 11 downregulated two-fold proteins were identified. Eight proteins displaying increased expression and one with decreased expression in conditioned media were validated using Western blotting. Real-time quantitative RT-PCR further disclosed induction of plasminogen activator inhibitor-1 (PAI-1), a T3 target, in a time-course and dose-dependent manner. Serial deletions of the PAI-1 promoter region and subsequent chromatin immunoprecipitation assays revealed that the thyroid hormone response element on the promoter is localized at positions –327/-312. PAI-1 overexpression enhanced tumor growth and migration in a manner similar to what was seen when T3 induced PAI-1 expression in J7-TRα1 cells, both in vitro and in vivo. An in vitro neutralizing assay further supported a crucial role of secreted PAI-1 in T3/TR-regulated cell migration. To our knowledge, these results demonstrate for the first time that proteins involved in the urokinase plasminogen activator system, including PAI-1, uPAR and BSSP4, are augmented in the extra- and intracellular space of T3-treated HepG2-TRα1 cells. The T3-regulated secretome generated in the current study may provide an opportunity to establish the mechanisms underlying T3-associated tumor progression and prognosis.

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 4789. doi:1538-7445.AM2012-4789
Abstract 4859: Ultra-sensitive detection of rare mutants by droplet digital PCR with conventional TaqMan assays
Authors: Hindson Benjamin , So Austin , Koehler Ryan , Troup Camille , Heredia Nick , Karlin-Neumann George , Saxonov Serge , White Helen
Published: August 2012

Molecular tests for genetic mutations play an important role in the diagnosis of cancer. Somatic mutations that drive the pathological features of most tumors have increasing promise as biomarkers for cancer prognosis and therapeutic efficacy. The detection of somatic mutations poses an analytical challenge due to the heterogeneous nature of most samples, where a gene carrying a mutation may differ from the highly abundant wild type sequence by only a single nucleotide. Although a variety of methods exist for mutation analysis, many have poor selectivity and fail to detect mutant sequence below 1 in 100 wildtype sequences. Methods that provide better discrimination and quantitation of somatic mutations are desirable. Here we present a simple strategy using droplet digital™ PCR (ddPCR™) for the detection of somatic mutations with high selectivity and sensitivity. Based on the simple principle of sample partitioning into water-in-oil microdroplets, this ddPCR method increases the abundance of a mutant DNA sequence up to 20,000 times compared to an equivalent bulk PCR reaction. Using conventional TaqMan chemistries and workflow, selectivities of up to 1/100,000 can readily be achieved in any laboratory. Here we present results on the use of ddPCR for the detection and quantitation of several clinically important mutations, including KRAS, c-KIT D816V and JAK2 from clinical samples such as bone marrow aspirates and FFPE. Results from ddPCR are compared to those of conventional approaches including allele specific real-time PCR and sequencing. This ddPCR method may play an important role in the earlier detection of cancer, monitoring the progress of disease and response to therapeutics.

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 4859. doi:1538-7445.AM2012-4859
Abstract 4860: Exon capture analysis of G-protein coupled receptors reveals activating mutations in GRM3 in melanoma
Authors: Prickett Todd D. , Wei Xiaomu , Cardenas-Navia Isabel , Teer Jamie , Lin Jimmy C. , Walia Vijay , Gartner Jared , Jiang Jiji , Cherukuri Praveen , Molinolo Alfredo , Davies Michael A. , Stamke-Hale Katherine , Margulies Elliott H. , Rosenberg Steven A. , Samuels Yardena
Published: August 2012

An important feature of cellular signaling involves the activation of plasma membrane-bound receptor complexes via endogenous ligands. G protein-coupled receptors (GPCRs), the largest human gene family, are known to be activated by ligands such as, thrombin, chemokines or glutamate, and have been shown to be important regulators of signaling pathways. Dysregulation via overexpression of diverse GPCRs has been well documented in primary and metastatic tumors cells such as breast, lung, prostate and gastric tumors, head and neck squamous cell carcinoma, and melanoma (1), however, knowledge of their genetic alterations is limited especially in malignant melanoma. Thus, further analysis of this gene family is warranted to determine if GPCR proteins play a role in melanomagenesis. In our current study, we used exon capture and illumina sequencing methods to analyze the mutational status of all the GPCRs in melanoma. This investigation revealed that one family member, GRM3 was frequently mutated in melanoma and that one of its mutations clustered within one position (Glu870Lys). Biochemical analysis of GRM3 alterations revealed that mutant GRM3 selectively regulated the phosphorylation of MEK leading to increased anchorage-independent growth and migration. In vivo studies revealed that overexpression of mutant forms of GRM3 result in increased lung macrometastases; whereas depletion of GRM3 in cells expressing mutant forms of GRM3 resulted in reduced xenograft tumor formation compared to equivalently treated wild type GRM3 cells. Furthermore, melanoma cells expressing mutant forms of GRM3 had reduced cell growth and reduced cellular migration after shRNA-mediated knockdown of GRM3 or treatment with a selective MEK inhibitor, AZD-6244, which is currently being used in phase II clinical trials. Our study yields a comprehensive map of genetic alterations in the GPCR gene family and suggests a potential novel therapeutic target for melanoma 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 4860. doi:1538-7445.AM2012-4860
Abstract 486A: Biological characterization of recombinant maspin in breast cancer cells
Authors: Bodenstine Thomas M. , Seftor Richard E. B. , Seftor Elisabeth A. , Khalkhali-Ellis Zhila , Pemberton Philip A. , Hendrix Mary J. C.
Published: August 2012

Mammary serine protease inhibitor (maspin) is a non-inhibitory member of the serine protease inhibitor (serpin) superfamily and is involved in mammary gland development. Loss of maspin expression is commonly observed during breast cancer progression while re-expression of maspin confers tumor suppressive capabilities. Cellular localization of maspin within the cytosol, nucleus, and association in complexes at the plasma membrane confer different properties in cancer cells adding to the complexity of maspin function. The recombinant form of maspin (rMas) when added to growth media of maspin-null cancer cells recapitulates many of the effects of exogenous maspin re-expression including inhibition of invasion through 3D matrices. These effects highlight the potential of rMas for therapeutic development as a novel adjuvant therapy. The aim of this study was to characterize the uptake, processing and distribution of wild-type and mutated forms of rMas in cancer cells. Using the MDA-MB-231, BT549 and Hs578T breast cancer cell lines we demonstrate that rMas is directly internalized by cancer cells and degraded rapidly. Time-lapse confocal microscopy using Alexa Fluor 594 labeled rMas and nuclear/cytoplasmic extraction of rMas following cellular uptake demonstrate that rMas is predominantly localized and processed in the cytosol. Wild-type rMas inhibited cancer cell invasion through collagen based matrices and this effect was independent of nuclear localization. Interestingly, site-directed mutagenesis of rMas to induce reported polymorphisms (Ile to Val 66, Pro to Ser 176, Leu to Val 187, Ile to Val 319) abrogated the ability of rMas to inhibit invasion. These preliminary experiments contribute to the characterization of rMas following internalization by cancer cells and aid in the therapeutic development of rMas as a potential therapy. Additionally, mutational data from this study support growing evidence that mutations in the maspin gene alter functionality in vitro, and may correlate to clinical outcomes in patients in which maspin is expressed in 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 486A. doi:1538-7445.AM2012-486A
Abstract 4885: mTOR complex 2 is involved in regulation of c-FLIP stability and sensitization of TRAIL-induced apoptosis
Authors: Zhao Liqun , Yue Ping , Khuri Fadlo R. , Sun Shi-Yong
Published: August 2012

The mammalian target of rapamycin (mTOR), a serine-threonine kinase related tightly to the phosphoinositide 3-kinase family, acts as a central molecule in regulation of cell proliferation and survival through forming two complexes primarily with raptor (mTOR complex 1; mTORC1) or rictor (mTOR complex 2; mTORC2). Compared with the mTORC1, relatively little is known about the biological functions of mTORC2. However, it is clear that both of the mTOR signaling pathways are dysregulated in human cancers, including lung cancer. Accordingly, novel ATP-competitive mTOR kinase inhibitors such as PP242 that inhibit both mTORC1 and mTORC2 have been developed for cancer therapy. In this study, we focus on addressing whether mTORC2 regulates apoptosis, particularly induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a potential cancer therapeutic protein tested in clinical trials. We found that PP242 synergized with TRAIL to augment apoptosis in human lung cancer cells. PP242 reduced the level of the short form of c-FLIP (FLIPS) and survivin with minimal effects on the expression of DR4 and DR5. Enforced expression of FLIPS, but not survivin, attenuated PP242/TRAIL-induced apoptosis; this suggests that FLIPS downregulation contributes to synergistic induction of apoptosis by the PP242 and TRAIL combination. Mechanistic studies revealed that PP242 decreased FLIPS stability, increased FLIPS ubiqutination and facilitated FLIPS degradation, suggesting that PP242 decreases FLIPS levels through promoting its degradation via an ubiqutination and proteasome-dependent mechanism. Interestingly, knockdown of rictor, but not raptor, mimicked PP242 in decreasing FLIPS levels and sensitizing cells to TRAIL. Moreover, rictor knockdown decreased the stability of FLIPS. These data together suggest that it is mTORC2 inhibition that mediates FLIPS downregulation and subsequent sensitization of TRAIL-induced apoptosis. Our findings hence provide the first evidence showing that mTORC2 positively regulates FLIPS expression, thereby, connecting mTORC2 signaling to regulation of the death receptor-mediated apoptosis pathway. (This study was supported by the Georgia Cancer Coalition Distinguished Cancer Scholar award and NIH/NCI R01 CA118450. FR Khuri and SY Sun are Georgia Cancer Coalition Distinguished Cancer Scholars)

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 4885. doi:1538-7445.AM2012-4885
Abstract 4891: Radiation enhances the efficacy of Bcl-2 and Bcl-XL inhibition in small cell lung cancer: A new concept of using radiation for targeted therapy through contextual oncogene addiction
Authors: Loriot Yohann , Mordant Pierre , Dugué Delphine , Gombos Andrea , Opolon Paule , Vozenin Marie-Catherine , Bourhis Jean , Geneste Olivier , Kraus-Berthier Laurence , Pierré Alain , Depil Stéphane , Soria Jean-Charles , Deutsch Eric
Published: August 2012

Purpose: Radiotherapy has a critical role in the treatment of small cell lung cancer (SCLC). Effectiveness of radiation in SCLC remains limited as resistance results from defects in apoptosis. Experimental Design: We investigated whether using a new Bcl-2/Bcl-XL inhibitor, S44563, can enhance radiosensitivity of SCLC cells in vitro and in vivo. We also explored the mechanisms of the potential interaction. Results: In vitro studies confirmed that S44563 induce apoptosis in SCLC cells by inducing hallmarks of apoptosis (cleaved caspase-3, sub-G1 fraction induction and induction of the mitochondrial caspase activation pathway). S44563 markedly enhanced sensitivity of H146 and H69 cells to radiation in clonogenic assay. In vitro experiments demonstrated a greater induction of apoptosis (sub-G1 fraction and cleaved caspase-3) with the combination as well as in vivo caspase-3 immunostaining. This positive interaction between S44563 and radiation was greater when S44563 was given during and after the completion of the radiation, which was explained by the radiation-induced over expression of anti-apoptotic proteins (Bcl-2 and Bcl-XL). in vitro studies based on gene expression and immunoblotting indicated that radiation activates NF-κB pathways which results in anti-apoptotic expression. In addition, S44563 combined with cisplatin-based chemo-radiation showed a dramatic tumor growth delay and increased overall survival in mouse xenograft models.Conclusion: This study underlines the critical role of sequence administration of targeted therapies with conventional therapies such as radiation and chemotherapy. SCLC cells which survive to IR highly rely on the induction of anti apoptotic proteins for their survival therefore yielding to the concept of “contextual oncogene addiction” to the Bcl-2/Bcl-XL pathway. These results suggest that radioresistance results in part from resistance to apoptosis in SCLC mediated by up regulation of Bcl-2/Bcl-XL. The inhibition of Bcl-2 and Bcl-XL leads to the induction of radiation-induced apoptosis and enhances radiation therapy both in vitro and in SCLC xenograft models. Our data suggest that targeting radiation induced survival pathways may constitute an efficient strategy to potentiate IR.

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 4891. doi:1538-7445.AM2012-4891
Abstract 4898: Methylseleninic acid potentiates multiple types of cancer cells to ABT-737-induced apoptosis involving Mcl-1, AKT-Bad, and mitochondrial cascade
Authors: Yin Shutao , Dong Yinhui , Li Jinghua , Lü Junxuan , Hu Hongbo
Published: August 2012

ABT-737, a novel small-molecule inhibitor of select Bcl-2 family survival proteins, holds excellent promise to complement current cytotoxic therapies for cancer, especially B-cell malignancies. However many types of solid cancer cells are resistant to ABT-737. One practical approach to improving its therapeutic efficacy is to combine with agents that can overcome such resistance to restore the sensitivity. In the present study, we sought to test the hypothesis that the cancer chemopreventive selenium compound methylseleninic acid (MSeA), known to suppress the expression of some Bcl-2 family members and AKT survival signaling, could synergistically sensitize cancer cells to ABT-737-induced apoptosis. Our results show that serum achievable levels of MSeA increased apoptosis induction by ABT-737 in several aggressive malignant cell lines: MDA-MB-231 human breast cancer cells, HT-29 human colon cancer cells and DU145 human prostate cancer cells, as evidenced by greater than additive enhancement of annexin V/FITC positive (apoptotic) cells and activation of multiple caspases and PARP cleavage. Mechanistic investigation demonstrated that MSeA significantly decreased the basal expression of Mcl-1 and ABT-737-induced Mcl-1 expression. Knocking down of Mcl-1 with RNAi increased ABT-737-induced apoptosis. More importantly, we identified activation of AKT phosphorylation and AKT-mediated inactivation of Bad by ser-136 and ser-112 phosphorylation as a novel mechanism involved in ABT-737 resistance which could be overcome by MSeA. In addition, we found that expression of Bax was required for the efficient execution of synergistic sensitization. These mitochondria-related apoptosis findings, to our knowledge for the first time, provide a strong mechanistic rationale for developing MSeA as a novel sensitizing agent of ABT-737 for cancer chemotherapy.

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 4898. doi:1538-7445.AM2012-4898
Abstract 4899: Altered receptor glycosylation confers cisplatin resistance in ovarian and colon cancer cells
Authors: Schultz Matthew J. , Swindall Amanda F. , Bellis Susan L.
Published: August 2012

Chemotherapy resistance is a significant clinical obstacle in the treatment of cancer. Platinum-based drugs are a mainstay of treatment in many solid cancers; however, tumor resistance to these drugs hampers long term efficacy. Resistance is multi-factorial, and theories to explain resistance are incomplete. In this study we report a novel mechanism for resistance to cisplatin involving changes in receptor glycosylation. Previous work in our lab has demonstrated enhanced colon cancer cell survival in cells expressing ST6Gal-I, a Golgi glycosyltransferase that adds the negatively-charged sugar, alpha2-6-linked sialic acid, to selected membrane proteins. We showed that sialylation of the Fas death receptor by ST6Gal-I decreases apoptotic signaling in response to Fas agonists by blocking DISC formation and receptor internalization. Elevated ST6Gal-I expression has been reported in many cancers, including ovarian and colon, and its expression is negatively correlated with patient prognosis. Interestingly, cisplatin has been demonstrated to mediate its cytotoxic effects, in part, through Fas receptor upregulation and activation, although the mechanism is not currently understood. Combining these results and observations, we investigated whether ST6Gal-I-mediated sialylation of the Fas receptor inhibits apoptotic signaling in response to cisplatin treatment, contributing to intrinsic cisplatin resistance. We determined the extent of cisplatin-induced apoptotic cell death by blotting for cleaved caspase-3, a terminal caspase, and detected decreased levels of activated caspase in ST6Gal-I expressing ovarian and colon cell lines. This result was observed in both a low endogenous ST6Gal-I cell model with forced ST6Gal-I expression, as well as a high endogenous ST6Gal-I expression cell model with shRNA ST6Gal-I knockdown. We also show sustained viability in cells expressing ST6Gal-I after cisplatin treatment by measuring a peptide protease substrate which is cleaved in live cells. Conversely, we detected a decrease in viability in non-ST6Gal-I expressing counterpart cell lines indicating that cells lacking ST6Gal-I expression are more sensitive to cisplatin-mediated cell death. Finally, we observed that cisplatin-mediated cell death is attenuated by treating cells with blocking antibodies to Fas, consistent with other studies implicating this receptor in cisplatin efficacy. Our findings suggest a novel mechanism contributing to platinum drug resistance in cancer cell populations and identify ST6Gal-I as a promising target for therapeutic intervention.

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 4899. doi:1538-7445.AM2012-4899
Abstract 4900: Bortezomib induces G2-M arrest through ROS-inducible phosphorylation of ATM independent on genotypes of KRAS in human colon cancer cells
Authors: Kim Seung-Mi , Hong Yong Sang , Hong Seung-Woo , Jin Dong-Hoon , Kim Tae Won
Published: August 2012

The use of cetuximab (CET) as an inhibitor of EGFR for treatment of colorectal cancer (CRC) has revolutionized. However, a number of CRC patients exhibits resistance to CET. In this report, we suggest the possibility of using bortezomib as a proteasome inhibitor in human colon cancer cells. Although bortezomib has been known to induce apoptosis and cell cycle arrest in various human cancer cells, the inhibitory mechanism of it was not clear. First, bortezomib induced G2-M arrest independent on genotype of KRAS in all of tested human colon cancer cells. Its treatment causes an increase of intracellular ROS levels and activation of ATM-CHK1 pathway, but not ATR. Also, activation of that pathway led to inactivation of cdc2. Moreover, treatment with NAC, Reactive Oxygen Species (ROS)scavenger, inhibited phosphorylation of ATM and subsequent to decrease of cell number at G2-M phase in response to bortezomib indicating that the increased level of ROS after exposure to bortezomib is a result of ATM phosphorylation. In addition, knockdown of endogenous ATM by RNA interference induced the decreased sensitivity to bortezomib. Therefore, these results suggest that bortezomib induces G2-M arrest through ROS-inducible ATM phosphorylation and responses to colon cancer cells independent on genotype of KRAS, implying a potential possibility of it in the treatment of CRC 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 4900. doi:1538-7445.AM2012-4900
Abstract 4906: Tamoxifen-mediated apoptosis relationship with ERα36 in gastric cancer cell BGC823
Authors: Li Yan , Deng Hao , Fan Jun , Zhou Diwei , Chen Ying , Wang Chengxin
Published: August 2012

Aim: The growth, apoptosis and estrogen receptor α36 (ERα36) expression and location changes in gastric cancer cell line BGC823 were observed, when dealt with different concentrations Tamoxifen (TAM), to characterize the role of TAM in gastric cancer growth and apoptosis and the mechanism of it. Materials and Methods: BGC823 cell was dealt with 10-6M and 10-5M TAM for 24h and 48h. Cell growth was assessed by WST1 assay. The mRNA and protein expressions of ERα36 were examined by RT-PCR and Western blot methods. Average optical densities were detected and processed using Student's t test analysis. Immunofluorescence assay was used to examine ER-α36 location in BGC823 cell. Hoechest33258 assay was used to examine apoptosis. Results: TAM could promote apoptosis and inhibit growth of BGC823 cell, and this effect had concentration dependant (P<0.05). TAM could promote ERα36 mRNA expression, and the increase level of ERα36 mRNA expression had concentration dependent of E2β(P<0.05). TAM could promote ERα36 protein expression, and the increase level of ERα36 protein expression had concentration dependent of E2β(P<0.05). The location of ERα36 had no change, when BGC823 cell dealt with TAM.Conclusions: TAM could promote apoptosis and inhibit growth of BGC823 cell, and the effect had concentration dependant. TAM could promote ERα36 expression in BGC823 cell, and the effect had concentration dependant. ERα36 may participate apoptosis mediated by Tamoxifen in Gastric Cancer Cell Line BGC823

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 4906. doi:1538-7445.AM2012-4906
Abstract 4978: The C/EBPbeta isoform, liver-enriched inhibitory protein (LIP) induces cell death in breast cancer cell lines
Authors: Abreu Maria M. , Sealy Linda
Published: August 2012

C/EBPbeta is a member of a family of basic-leucine zipper transcription factors. It has been shown to be a key regulator of growth and differentiation in the mammary gland. There are three different protein isoforms of C/EBPbeta. C/EBPbeta-1 and -2 are transactivators, and differ by just 23 N-terminal amino acids present in beta-1 only. C/EBPbeta-3 (LIP) lacks the transactivation domain and represses transcription. Here, we report that LIP expression stimulates autophagy and induces cell death in breast cancer cell lines. Overexpression of LIP is incompatible with cell growth and when cell cycle analysis was performed in the LIP-MDA-MB-231 breast cancer cell line, a DNA profile of cells undergoing apoptosis was not observed. Instead, LIP expressing cells appeared to have large autophagic vesicles when examined via electron microscopy. Autophagy is an evolutionarily conserved cellular process responsible for self-cannabalization through a lysosomal degradation pathway. Autophagy was further assessed in LIP expressing and control breast cancer cells by monitoring the development of acidic vesicular organelles and conversion of LC3 from the cytoplasmic form to the autophagosome form. LIP expression leads to an increase in acidic vesicles. In addition, activation of LC3 was detected in LIP expressing cells by immunoblot analysis and immunofluorescence studies. Interestingly, we find that LIP expression not only leads to massive and rapid cell death in the MDA-MB-468 breast cancer cell line, but cell cycle profiling reveals a dramatic increase in DNA content in LIP expressing cells. We present data that the induction of autophagy appears to accompany or possibly follow the engulfment of neighboring cells by the LIP expressing cells. Recently, there have been reports of different cell death processes that occur due to cell internalization. LIP overexpression may be one important factor that is driving cell engulfment resulting in cell death.

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 4978. doi:1538-7445.AM2012-4978
Abstract 4989: Selective inhibitors of the inositol-requiring enzyme 1 kinase domain
Authors: Griffin Carly , Abibi Ayome , Subramaniam Ratheesh , Zaidi Hassan S. , Marcellus Richard , Poda Gennadiy , Prakesch Michael , Uehling David , Canny Marella , Chiovitti David , Durocher Dan , Sicheri Frank , Al-awar Rima
Published: August 2012

Inositol-requiring enzyme 1 (IRE1) is a key player in endoplasmic reticulum (ER) stress conditions. IRE1 is a highly conserved ER-membrane protein activated by the unfolded protein response (UPR) or other ER-stressors, such as hypoxia and glucose deprivation. Stress causes IRE1 to undergo oligomerization and autophosphorylation, which triggers nonconventional splicing of XBP-1 mRNA by its cytosolic endonuclease domain. The resulting spliced XBP-1 protein (XBP-1s) is a transcription factor that serves to increase the protein folding capacity and ultimately restore homeostasis of the ER. Thus, sustained IRE1 activity promotes cell survival and inhibition of IRE1 may be a potential therapeutic target for diseases associated with chronic ER-stress, such as neurodegenerative disorders, diabetes, and cancer. Proper RNase function of IRE1 is dependent upon autophosphorylation of the kinase domain. We therefore screened a library of 380 known kinase inhibitors, consisting of tool compounds and compounds already in clinical use, for those with activity against the human IRE1 kinase domain. As a result, a number of compounds were found that potently inhibit phosphorylation of a biotin-STK peptide substrate in the presence of human IRE1 (IC50 < 1 μM), as determined by HTRF (homogeneous time-resolved fluorescence). The lead compounds were then screened in cell-based assays. Several ATP-mimetic compounds with diverse chemotypes were found to inhibit expression of XBP-1s in human cancer cells under pharmacologically-induced acute ER-stress. Furthermore, transcriptional targets of XBP-1s and phosphorylation of IRE1 were also negatively affected by these compounds. Interestingly one compound in particular, a known ROCK1 (Rho-associated coiled-coil containing protein kinase 1) inhibitor (OICR000287A), was significantly more toxic to cells under acute ER-stress than to unstressed cells. This study suggests that development of ATP-competitive inhibitors of human IRE1 is a promising therapeutic strategy for ER-stress related diseases including myeloma, pancreatic and other secretory cancers.

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 4989. doi:1538-7445.AM2012-4989
Abstract 5002: Comprehensive DNA methylation profiling of human hepatocellular carcinoma
Authors: Nishimura Takafumi , Nishida Naoshi
Published: August 2012

 Transcriptional inactivation of several tumor suppressor genes via epigenetic mechanism has been reported in many types of cancers, including hepatocellular carcinoma (HCC), and thus has been considered as critical events in multistage carcinogenesis. We conducted a comprehensive genome-wide analysis to elucidate distribution and characteristics of genes that subject to cancer-related DNA methylation in human HCC, especially on the context of development of methylation alteration in early stage of human hepatocarcinogenesis.  With written informed consent, five well-differentiated HCC tissues and two corresponding matched non-cancerous liver tissues were obtained at the time of hepatectomy (2 tumors) or orthotopic living-donor liver transplantation (3 tumors and 2 non-tumors). After bisulfite modification, the converted DNA was subject to hybridization on Infinium Human Methylation BeadChip 450K (Illumina, Inc., San Diego, CA) that includes 485,764 cytosine positions of the human genome including gene promoters and repetitive DNA elements. The methylation level for each CpG dinucleotides was represented as a beta value according to the fluorescent intensity ratio. In order to identify alteration of methylation profile between well-differntiated HCC and non-tumor liver, difference of average beta values between tumor and non-tumor was calculated.  Of 25,978 CpG loci that represent each gene, differences of average beta values of 24,805 loci (95.5%) were within 30%. These were considered as constitutively methylated or unmethylated. Tumor-specific demethylation was found at 589 loci representing 414 genes. Of these, 85.0% were located outside CpG islands, shore or shelf. Tumor-specific demethylation rarely occurred within CpG islands (3.4%). On the other hand, tumor-specific DNA methylation was found at 137 loci representing 108 genes. Of these, 65.7% were located within CpG islands. According to previously published information (Lee, TI. et. al. Cell 125:301-313, 2006), 39 genes (36%) out of these 108 genes with tumor-specific methylation have been reported to be occupied with polycomb group protein SUZ12 in embryonic stem cells.  Tumor-specific methylation occurring at CpG islands, especially of polycomb target genes, may contribute to hepatocarcinogenesis. This finding further suggests an importance of epigenetic mechanism on developing human HCC.

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 5002. doi:1538-7445.AM2012-5002