bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 474: The essential role of Giα2 in prostate cancer progression
Authors: Zhong Miao , Clarke Shineka , Khan Shafiq A. 
Published: August 2012

Abstract
Basic and clinic research data have suggested that signaling of G-protein-coupled receptors (GPCRs) is amplified in malignant prostate tumors and facilitates the transition of primary cancer cells to the androgen independent stage. Oxytocin (OXT) is a neurohypophyseal peptide hormone that regulates normal prostate functions. However, the information is very limited about the effect of OXT on prostate cancer progression. The effect of OXT is mediated by a GPCR that promiscuously activates multiple G-proteins including Gqα and Giα. Recently, we have shown that OXT receptor (OXTR) is the primary target of OXT in androgen independent prostate cancer cell lines (DU145 and PC3). Moreover, activated OXTR has been shown to promote migration of PC3 cells via a pertussis toxin (PTx) sensitive Gi/o-protein dependent mechanism. In the present study, OXTR was shown to be increased in advanced prostate cancer tissues when compared with normal prostate tissues. Expression of OXTR protein is detected in DU145 and PC3 prostate cancer cell lines but not in the immortalized prostate epithelial cells (RWPE1). OXT treatment (100 nM) inhibited the foskolin (5 µM) induced cAMP accumulation in PC3 cells, as indicated by the cAMP luciferase reporter assay. This data has provided direct evidence that supports the involvement of Giα in the OXTR signaling in PC3 cells. There was no difference in expression of Giα isoforms (Giα1-3) at the mRNA level between normal (PrEC, RWPE1 and RWPE2) and prostate cancer cell lines (LNCaP, DU145, PC3, and PC3M). However, western blot analysis showed that Giα2 is the only Giα family member detectable in PC3 cells. PTx (100 ng/ml) has been shown to abolish the OXT-induced migration of PC3 cells. Overexpression of PTx resistant Giα2, but not wild type Giα2, restored the effect of OXT in PTx pretreated PC3 cells. Accordingly, genetic silencing of Giα2 expression by siRNA eliminated the OXT-induced migration of PC3 cells. Unexpectedly, knock down Giα2 also inhibited the EGF (3 ng/ml) induce migration of PC3 and DU145 cells. In conclusion, Giα2 may play an essential role in prostate cancer 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 474. doi:1538-7445.AM2012-474
Abstract 4741: Development of a novel therapeutic agent for breast cancer based on a new pathway analysis of triple-negative breast cancer
Authors: Fujimori Minoru , Fujita Tomoyuki , Mizukami Tamio , Okawara Tadashi , Inoue Kengo 
Published: August 2012

Abstract
We developed a novel method for drug discovery using active compounds as pharmacodynamic biomarkers in triple-negative breast cancer cell lines. [Materials and Methods] Compounds that selectively inhibit proliferation of triple-negative breast cancer were screened in triple-negative breast cancer cell lines (MDA-MB231, MDA-MB468 and HCC-38) and control MCF7 and HeLa cell lines. A small molecule library was designed to seek structural diversity by chemical informatics and a total of 30,000 synthetic compounds were assessed considering drug similarities. The differences in gene expression profiles in the cell lines between before and after the addition of the selected compounds were analyzed and compared with the control cells. [Results] Seven compounds that exhibited inhibitory effects on the triple-negative breast cancer cell lines were found in the compound library. These compounds exhibited inhibitory activity with IC50-values ranging from 1.2 to 10.8 μM. The results of the microarray analysis indicated several pathways including the irinotecan pathway that changed specifically in the triple-negative breast cancer cell lines by the addition of the compounds.[Conclusion] A research strategy to screen a compound library with structural diversity and develop a drug discovery system using active compounds as pharmacodynamic biomarkers can be widely applied as a new approach for developing innovative personalized medicine.
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 4741. doi:1538-7445.AM2012-4741
Abstract 4744: Development of an immunoproteasome fluorescent substrate: A functional proteomics tool
Authors: Lee Na-Ra , Carmony Kimberly C. , Wu Ying , Miller Zachary , Kim Kyung-Bo 
Published: August 2012

Abstract
Introduction: This research was conducted to develop the first immunoproteasome fluorescent substrate. The immunoproteasome is an alternate form of the constitutive proteasome with distinct catalytic subunits. While immunoproteasomes appear to generate peptides for MHC class I antigen presentation, their functions are still not completely understood. Antibody-based studies have shown that immunoproteasome catalytic subunits are expressed in a variety of cancers, suggesting they may play important roles in this disease. However, antibodies bind both active and inactive subunits, rendering these studies incapable of correlating immunoproteasome activity with disease progression. Although fluorescent peptide substrates are widely used to monitor proteasome activity, those currently available are cleaved by both forms of the proteasome. Therefore, fluorescent substrates selectively cleaved by the immunoproteasome are needed to correlate their activity with cancer progression. Experimental Procedures: The fluorescent substrate was synthesized by replacing the epoxyketone pharmacophore of the immunoproteasome-selective inhibitor YU-102 with a 7-amino-4-methylcoumarin (AMC) fluorogenic moiety. The rates of hydrolysis of the resulting substrate, YU-102-AMC, by both purified constitutive proteasomes and immunoproteasomes were evaluated by monitoring the release of AMC over time. Hydrolysis of this substrate was also investigated in T1 and T2 cell lysates. Data Summary: The structure of the fluorescent substrate YU-102-AMC was confirmed by mass spectrometry and nuclear magnetic resonance spectroscopy. YU-102-AMC was preferentially cleaved by purified immunoproteasomes in comparison with purified constitutive proteasomes. This preferential cleavage by immunoproteasomes was confirmed in lysates of cancer cell lines T1 and T2. Conclusions: We have successfully developed YU-102-AMC, an immunoproteasome fluorescent substrate which facilitates quantification of immunoproteasome activity in cancer cell lysates. This substrate will be utilized to examine a correlation between immunoproteasome activity and cancer progression.
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 4744. doi:1538-7445.AM2012-4744
Abstract 475: uPAR and cathepsin B knockdown inhibits radiation-induced PKC integrated integrin signaling to the cytoskeleton and migration of glioma initiating cells
Authors: Alapati Kiranmai , Dasari Venkata Ramesh , Gopinath Sreelatha , Malla Rama Rao , Gujrati Meena , Rao Jasti S. 
Published: August 2012

Abstract
Glioblastoma (GBM) remains one of the most fatal and least successfully treated solid tumors. It is evident that some cancer cells with stem cell properties (known as glioma initiating cells; GICs) survive conventional treatments and are involved in the recurrence of tumors. In the present study, CD133+ GICs were isolated from established U251 and 5310 glioma cell lines and subjected to radiation and transfection with shRNA against uPAR and cathepsin B so that we could study the events related to cell migration. Simultaneous downregulation of uPAR and cathepsin B (pUC) caused the disruption of radiation-induced complex formation of pPKC∈/α:integrinβ1 and PKC∈:integrinβ1 in glioma cells as well as in GICs as was observed by immunoprecipitation analysis. Further, pUC treatment also inhibited the PKC/integrin signal through FAK by disintegrating the association of FAK and the cytoskeletal molecules vinculin and α-actinin. It was also observed that inhibition of radiation-induced ERK phosphorylation by pUC directed a negative feedback mechanism over the FAK signaling molecules that led to an extensive reduction in the cytoskeletal organization, and thereby generating a migratory arrest. Further confirmation was obtained by treating the cells with U0126 (10 µM), a MEK inhibitor, and rottlerin (200 µM), a PKC inhibitor. pUC treatment efficiently inhibited the co-localization of pPKC∈/α/integrinβ1, PKC∈/integrinβ1, FAK/vinculin and FAK/α-actinin in the brain tumor sections of mice implanted with glioma cells and GICs. In conclusion, shRNA-mediated knockdown of uPAR and cathepsin B could be an effective treatment strategy for controlling highly invasive glioma cells and treatment-resistant glioma initiating cells.
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 475. doi:1538-7445.AM2012-475
Abstract 4751: Structure and inhibition of mitogen-activated protein kinase kinase 4 (MEK4): A prostate cancer pro-invasion protein
Authors: Krishna Sankar Narayan , Luan Chi-Hao , Minasov George , Shuvalova Ludmilla , Farmer Rebecca L. , Nibbs Antoinette , Scheidt Karl A. , Anderson Wayne F. , Bergan Raymond C. 
Published: August 2012

Abstract
Introduction: Metastasis of Prostate Cancer (PCa) represents the second highest cause of death due to cancer among men in the United States. If this unregulated movement of cells can be inhibited, mortality arising from PCa will be greatly reduced. Our group has shown that Mitogen-activated protein kinase kinase 4 (MAP2K4/MEK4), a 399 amino acid protein, activates pro-invasion signaling pathways in human PCa. Further, we have shown that 4,5,7-trihydroxyisoavone (genistein) inhibits MEK4 kinase activity, cell invasion and metastasis of human PCa cells in a murine model. While therapeutically effective, genistein represents a non-chemically optimized natural product with additional undesired effects such as estrogenic receptor stimulation. Recognizing that MEK4 represents a novel and important therapeutic target, we have sought to characterize its structure, biochemical function and have synthesized genistein analogs designed to target it. Summary of Results: Using X-ray crystallography we have obtained a 3.38Å resolution structure of the MEK4 catalytic domain. We are in the process of improving our resolution, and of deriving 3D structures with inhibitors bound to MEK4. We have evaluated biophysical interactions between MEK4 and ligands (i.e., genistein and its analogs). Ligand binding to a protein tends to increase its stability, thereby increasing the temperature of denaturation, or melting. Using a fluorescence thermal shift (FTS) assay, we demonstrated that genistein and 6 of 39 novel analogs thermally stabilized MEK4 in a concentration dependent manner, consistent with MEK4 binding. We identified a similar pattern in 5 compounds from a commercial library, one of which was staurosporine - a broad spectrum protein kinase inhibitor. We developed and characterized a novel in vitro MEK4 kinase assay, using kinase dead p38MAPK (K53A) as substrate. In human PCa cells, MEK4 activates the p38 MAPK pro-invasion pathway. To date, we have used this assay system to demonstrate that staurosporine inhibits MEK4 with nanomolar IC50 values. Conclusions and Future Directions: MEK4 is a novel target for therapeutic intervention in PCa. Our ultimate goal is to synergistically utilize structural and biochemical information to inform the synthesis of inhibitors that specifically and selectively act upon MEK4 to inhibit human PCa metastasis in man.
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 4751. doi:1538-7445.AM2012-4751
Abstract 4752: Selective inhibition of cancer metastasis with a novel small therapeutic molecule
Authors: Xu Li , Farmer Rebecca , Huang Xiaoke , Pruell Sean , Voll Eric , Pavese Janet , Valsecchi Matias , Biddle Margaret , Nibbs Antoinette , Avram Michael , Scheidt Karl A. , Bergan Raymond C. 
Published: August 2012

Abstract
Prostate cancer (PCa) is the second most common cause of cancer death in US males. Death is typically caused by metastasis. Naturally occurring isoflavanones have been reported to be a class of compounds that effectively inhibit PCa motility and metastasis. This led us to use these compounds as a synthetic scaffold starting point. By integrating fragment-based diversification synthesis with chemi-driven biological selection, we discovered novel small molecule therapeutics with increased selectivity and potent efficacy. We thereby efficiently synthesized a new class of bioactive compounds that inhibit cell motility in vitro and inhibit human PCa metastasis in a murine model at low nanomolar concentrations. Extensive investigations indicate high specificity at the molecular and cellular levels, and failed to identify toxicity, even at high doses administered over extended periods. Importantly, efficacy against several cancer types was also demonstrated. Target validation studies used our lead as a chemical probe, and point to inhibition of ATM/ATR interaction with specific substrate proteins as important. Together, these studies indicate that we have successfully discovered a novel compound, acting upon a novel pharmacologic target, which selectively inhibits human PCa metastasis. Taken with our favorable preclinical toxicological data, these findings support movement of our lead compound into early phase human trials.
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 4752. doi:1538-7445.AM2012-4752
Abstract 4753: Targeting nucleotide excision repair: Chemical synthetic lethality and biology-based combination therapy
Authors: Turchi John J. , Lee Jiyoon , Hendricks Jeremiah , Neher Tracy M. , Fitch Richard W. 
Published: August 2012

Abstract
As DNA repair defects in cancer can be exploited for therapeutic benefit via synthetic lethality, new DNA repair targets and compounds to inhibit them will expand the armamentarium against cancer. While most targeted therapies involve disrupting enzyme-substrate interactions we have pursued targeting protein-DNA interactions to validate an entire new class of molecular interactions that can be targeted with small molecule drugs. We have focused on the nucleotide excision repair (NER) pathway and two proteins, the single-stranded DNA binding protein, replication protein A (RPA) and the xeroderma pigmentosum group A (XPA) protein. We have identified and developed small molecule inhibitors (SMIs) of each target. In vitro analysis of XPA SMI has led to a 50-fold increase in potency and revealed structure-activity relationships that define the important pharmacophores for XPA interaction. Both reversible and irreversible SMIs of RPA have been identified and cellular analysis of irreversible RPA SMI's revealed single agent anticancer activity at sub-micro-molar concentrations. The degree of the anticancer effect of cellular RPA inhibition varied among cancer types and was dependent on the DNA repair phenotype. Synergy between NER inhibition and cisplatin will be presented and as a function of DNA repair phenotype. These data demonstrate the ability to develop SMI of protein-DNA interactions that impact DNA repair and can be employed to increase the sensitivity of repair deficient tumors to DNA damaging therapeutics. This works was supported by NIH grant R01-CA82741 to JJT
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 4753. doi:1538-7445.AM2012-4753
Abstract 4760: Inhibition of c-myc by the triterpenoid celastrol
Authors: Hu Angela , Wang Huabo , Pendleton Kelsey , Prochownik Edward V. 
Published: August 2012

Abstract
c-Myc is a bHLH-ZIP transcription factor that is deregulated in a variety of human cancers. More specifically, c-Myc heterodimerizes with another bHLH-ZIP partner protein, Max, to bind to specific sequences (E-Boxes: CAC/TGTG) located near the transcriptional start sites of its numerous target genes. Because c-Myc's highly variable downstream effects are difficult to attack individually, directly inhibiting the association between c-Myc and Max association by interfering with their bHLH-ZIP-mediated heterodimerization has emerged as an attractive therapeutic strategy. Thus far, high throughput screens of chemical libraries have identified a number of small molecules that specifically inhibit the c-Myc-Max association. However, these synthetic compounds and their analogs are generally of low potency and therefore have limited clinical utility. Here we report identification of celastrol, a naturally occurring triterpenoid, as a potent c-Myc inhibitor. We sought to further assess celastrol's ability to inhibit c-Myc-Max interaction and cell growth, and determine its structure activity relationship. Surface plasmon resonance and electrophoretic mobility shift studies revealed that celastrol specifically binds to c-Myc and prevents both its interaction with Max, and subsequent DNA binding with a Kd in the low micromolar range. Co-immunoprecipitation studies confirmed that the dose-dependent disruption of c-Myc-Max heterodimers by celastrol could also be achieved in c-Myc-overexpressing human HL60 promyelocytic leukemia cells. Moreover, in vitro data demonstrated that celastrol significantly inhibited both HL60 and Burkitt's lymphoma cell growth with IC50s in the nanomolar range. However, modifications to the C-28 carboxylic acid group of celastrol eliminated c-Myc binding, suggesting that celastrol binds to c-Myc via this functional group. This structure activity relationship may provide a basis for the development of more pharmacologically suitable analogs. Together these results suggest that celastrol is among the most potent Myc-Max disruptors yet identified, and suggest a mechanism of action. Celastrol thus represents a promising new agent with which to target c-Myc and provides a new structural chemical platform for further pharmaceutical development.
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 4760. doi:1538-7445.AM2012-4760
Abstract 4763: Targeting p300 for inhibiting triple negative breast cancer
Authors: Liao Daiqing , Yang Heng , Luo Jian 
Published: August 2012

Abstract
Breast cancer (BC) can be classified into four main subtypes: normal-like, HER2 overexpressing, luminal A and B, and basal-like BC. Normal-like BC cells exhibit gene expression pattern resembling basal epithelial cells. Erb-B-2/HER2-positive BC cells display high levels of Her2 expression. Luminal tumors show heightened expression of luminal cytokeratins and genes specific to the luminal epithelial cells, and are generally ER positive. Basal-like BC is characterized by the lack of expression of ER, progesterone receptor (PgR), and HER2. Triple-negative BC (TNBC) is defined by the lack of expression of ER, PgR and HER2 with distinct molecular, histological and clinical characteristics. Among the four BC subtypes, TNBC shares many of the molecular features of basal-like BC. Patients with TNBC have worse prognosis than those with other types of BC due to residual diseases that are resistant to chemotherapy and display heightened tendency to disseminate to distant organs. Available targeted therapies are ineffective for TNBC. Interestingly, cells derived from TNBC contain an elevated proportion of tumor cells with stem cell traits. These cells, known as cancer stem cells (CSCs), can self renew, differentiate into other types of cells in the tumor bulks, and efficiently promote tumor regrowth. CSCs are highly resistant to chemotherapy due to the expression of antiapoptotic genes. Several highly active signaling pathways, including cytokine-JAK-STAT3, Wnt-β-catenin, and Hippo-TAZ cascades, support the survival and sustained self-renewal of CSCs. One remarkable feature of these diverse signaling pathways is the reliance on the functions of the coactivators and acetyltransferases p300 and its paralog CBP for the expression of the effector genes that underlie the CSC phenotypes. We therefore hypothesize that inhibition of p300/CBP is an effective strategy for treating TNBC. Using an unbiased ultra high-throughput screening, we have identified small chemical compounds that were highly toxic to TNBC cell line MDA-MB-231 and potently inhibited the enzymatic activity of p300. Validation experiments revealed that a specific compound, L002, with the IC50 of 1.98 µM against p300 in vitro suppressed histone acetylation at several known sites of p300 acetylation in cell-based assay. L002 was highly toxic to MDA-MB-231 cells but much less so to MCF7 derived from a luminal BC. Experiments are underway to examine the effects of L002 on the survival of breast CSCs. (This work was supported by Bankhead-Coley Cancer Research Program of the Florida Department of Health.)
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 4763. doi:1538-7445.AM2012-4763