bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2776: Inhibition of Nek2 by novel small molecules affects proteasome activity
Authors: Meng Lingyao , Warner Steven L. , Mollard Alexis , Vankayalapati Hariprasad , Sharma Sunil , Bearss David J. 
Published: August 2012

Abstract
Nek2 is a serine/threonine kinase that has been associated with centrosome function and cell cycle progression. Nek2 overexpression has been reported in several tumor types including breast and lung cancers. We have previously shown that elevated expression of Nek2 in clinical samples of multiple myeloma (MM) correlates with bortezomib resistance. Furthermore, the overexpression of Nek2 in MM cell lines decreases sensitivity to bortezomib and knockdown with RNAi sensitizes bortezomib resistant cells. Due to the proteaseome inhibitory activity of bortezomib, we hypothesized that Nek2 overexpression may increase proteasome activity. 26S proteasomes were isolated by ultracentrifugation from stably transfected Hela cells (+Nek2 or +GFP) and Nek2 was shown to be involved in the 26S proteasome complex by western blot. Proteasome activity assays were performed both biochemically and in cell culture demonstrating that proteasome activity in Hela+Nek2 is significantly higher than in Hela+GFP. Furthermore, the isolated 26S proteasomes were incubated with novel Nek2 inhibitors (HCI-2184 and HCI-2389) resulting in a significant reduction in proteasome function when used as single agents or in combination with bortezomib. HCI-2184, a reversible inhibitor of Nek2, demonstrated an IC50 value in the range of 13-38 nM, and HCI-2389, an irreversible inhibitor of Nek2, showed an IC50 value between 8-26 nM. Similarly, both compounds significantly increased the efficacy of bortezomib in inhibiting the proteasome activity. These results were confirmed in multiple cancer cell lines, including ARP1 (human MM cell line), H299 (human lung cancer cell line) and K28 (mouse Leydig tumor cell line). The effect of inhibiting Nek2 on cell cycle was also investigated. The expression levels of cyclinB1 and cdc2, proteins degraded by the proteasome for cells to exit mitosis, were increased in HCI-2389 treated Hela+Nek2 and to a lesser extent Hela+GFP treated cells. While Nek2 overexpression leads to the down-regulation of cyclinB1 and cdc2, HCI-2389 treatment successfully rescued this effect. Flow cytometry data showed that both treatments of HCI-2184 and HCI-2389 significantly arrested Hela+Nek2 and Hela+GFP in G2/M phase after 24 hours at concentration as low as 10nM. In conclusion, we have discovered a novel biological function of Nek2 related to elevated proteasome activity. We also demonstrated that our novel Nek2 inhibitors efficiently inhibit Nek2 function, resulting in reduced proteasome activity. These Nek2 inhibitors have the potential to be applied clinically for treatment of the MM patients resistant to bortezomib.
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 2776. doi:1538-7445.AM2012-2776
Abstract 2778: Development of non-covalent reversible proteasome inhibitors
Authors: Kazi Aslamuzzaman , Ozcan Sevil , Lawrence Harshani , Sebti Said M. 
Published: August 2012

Abstract
Numerous cell cycle, apoptosis and angiogenesis-regulatory proteins undergo ubiquitin proteasome-dependent proteolysis. A proteasome inhibitor Velcade was approved for the treatment of multiple myeloma. However, Velcade is a covalent and slowly reversible inhibitor and is associated with undesired side effects. Non-covalent inhibitors with potentially less toxicity are desirable. In this abstract we report on a family of non-covalent inhibitors that resulted from our HTS screen of a 50,000 compound library against the chymotrypsin-like (CT-L) activity of purified 20S proteasome. Our initial hit PI-1833 (IC50 value = 0.5 uM) was used as a starting point for structure activity relationship studies that led to highly potent (IC50 value = 20 nM) and cell permeable derivatives. In addition to inhibiting CT-L in human breast cancer cells, these derivatives also induced the accumulation of two proteasome target proteins Bax and p27KIP, indicating their ability to inhibit proteasome activity in intact cells. Furthermore, these proteasome inhibitors also induced apoptosis and inhibited tumor cell growth. Further mechanistic studies as well as in vivo anti-tumor efficacy studies are ongoing.
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 2778. doi:1538-7445.AM2012-2778
Abstract 2779: Withaferin A inhibits the malignant pleural mesothelioma growth in vitro and in vivo
Authors: Yang Huanjie , Wang Ying , Cheriyan Vino T. , Wu Wenjuan , Cui Cindy Qiuzhi , Polin Lisa A. , Pass Harvey I. , Dou Q. Ping , Rishi Arun K. , Wali Anil 
Published: August 2012

Abstract
The medicinal plant Withania somnifera has been used for over centuries in Indian Ayurvedic medicine to treat a wide spectrum of disorders. Withaferin A (WA), a bioactive compound that is isolated from this plant, has recently been found to have anti-inflammatory, immuno-modulatory, anti-angiogenic, and anti-cancer properties. Here we investigated malignant pleural mesothelioma (MPM) suppressive effects of WA and the molecular mechanisms involved. WA inhibited growth of the murine as well as patient-derived MPM cells in part by decreasing the chymotryptic activity of the proteasome that resulted in accumulation of ubiquitinated proteins. WA suppression of MPM growth also involved elevated apoptosis as evidenced by activation of caspase-3, elevated levels of pro-apoptotic Bax protein and cleavage of poly-(ADP-ribose)-polymerase. Our studies including gene-array based analyses further revealed that WA suppressed a number of cell growth and metastasis-promoting genes including c-myc. WA treatments also promoted cleavage of vimentin as well as stimulated expression of CARP-1/CCAR1, a novel transducer of cell growth signaling. Knock-down of CARP-1, on the other hand, interfered with vimentin cleavage and MPM growth inhibitory effects of WA. Administration of 5mg/kg WA by daily i.p injections inhibited growth of murine MPM cell-derived tumors in vivo in part by inhibiting proteasome activity and stimulating apoptosis. Together our in vitro and in vivo studies suggest that WA suppresses MPM growth by targeting multiple pathways that include blockage of proteasome activity and stimulation of apoptosis, and thus holds promise as an anti-MPM agent.
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 2779. doi:1538-7445.AM2012-2779
Abstract 278: Post-transciptional activation of anti-oxidant enzymes by imatinib
Authors: Terry Emily N. , Diamond Alan M. 
Published: August 2012

Abstract
Patients with Chronic Myelogenous Leukemia (CML) can be treated with targeted bcr-abl kinase inhibitors, such as imatinib. Recently, we reported that mononuclear cells obtained from individuals treated with imatinib often exhibit an increase in the enzyme activity of the antioxidant selenoprotein, glutathione peroxidase (GPx). Treatment of the bcr-abl positive cell line KU812 resulted in increased GPx enzyme and GPx1 protein levels in a dose (100-150 nM) and time (0-7 days) dependent manner, with a maximal increase of 3-fold. Imatinib-induced changes in other anti-oxidant enzymes were also assessed. Of these, no change in the levels of either catalase or GPx-4 were detected, although the levels of manganese superoxide dismutase (MnSOD) increased by a maximal level of 4-fold in imatinib-treated cells. Similar results were obtained in another bcr-abl positive, CML cell line, MEG-01. The elevation in the levels of these proteins occurred via a post-transcriptional mechanism as no increase in the steady state levels of the corresponding mRNA was detected by RT-PCR. The effect of imatinib was likely to be dependent on the presence of the bcr-abl fusion product as no changes in either GPx-1 or MnSOD were detected in either the immortalized lymphocyte cell line GM10832 or the prostate cancer-derived LNCaP human cell lines, neither of which contain bcr-abl. Since the mammalian Target of Rapamycin (mTOR) is a known protein substrate for the abl kinase, and mTOR activity can regulate protein translation, it was investigated whether inhibiting mTOR with rapamycin (1ng/ml) affected GPx-1 and MnSOD levels. Exposure of the KU812 and MEG-01 cells, as well as LNCaP and GM10832 with rapamycin resulted in increased GPx-1 protein and enzyme levels (2- to 4-fold), but had no measurable effects on MnSOD. These results indicate that imatinib, likely by the inhibition of bcr-abl, can post-transcriptionally enhance both GPx-1 and MnSOD levels, although by different mechanisms. These data may have therapeutic significance as both of these anti-oxidant enzymes may influence several different clinically relevant biological processes, including DNA damage susceptability, cell signaling and apoptosis.
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 278. doi:1538-7445.AM2012-278
Abstract 2896: Nanoparticle co-delivery of RNAi and chemotherapy for the treatment of drug-resistant cancers
Authors: Shi Jinjun , Votruba Alexander R. , Xu Xiaoyang , Langer Robert , Zetter Bruce R. , Farokhzad Omid C. 
Published: August 2012

Abstract
The emergence of drug resistance has been a critical barrier for effective cancer chemotherapy. Recently, RNA interference (RNAi) has shown promise in suppressing the over-expression of drug resistance-associated proteins such as P-glycoprotein and Prohibitin1, and in treating multidrug resistant cancers through combination with chemotherapy. Nevertheless, the safe and effective delivery of RNAi therapeutics (e.g., siRNA and miRNA) to target cells remains a major hurdle for their clinical applications, and the co-delivery of RNAi and chemotherapeutic agents in a controlled fashion requires specific delivery vehicles. Herein, we present a novel nanoparticle (NP) platform to tackle the challenges associated with the delivery of siRNA and chemotherapeutic drugs, using biodegradable and biocompatible polymers and lipids. The hybrid lipid-polymer NP has a differentially charged hollow core/shell nanostructure which provides the delivery system with three distinct functional features: (i) a positively charged inner hollow core for dense loading of siRNA; (ii) a middle hydrophobic polymer layer for the encapsulation of anti-cancer drugs (e.g., taxanes) and for the controlled release of both siRNA and drug; and (iii) a relatively neutral lipid-polyethylene glycol (PEG) surface to keep the NP stable and prolong its systematic circulation. Moreover, such hybrid NPs can be formulated in a simple and robust way that could facilitate future scale-up. By screening various factors, such as inner cationic lipids, outer PEG chain length, and formulation parameters, the hybrid lipid-polymer NPs show excellent in vitro knockdown efficacy at low doses of siRNA, with greater than 80% luciferase silencing at an siRNA dose of 0.4 pmol (4.0 nM) and ∼ 95% silencing at a dose of 2.0 pmol (20 nM). These NPs can also efficiently reduce the expression of drug resistance-associated proteins (e.g., MDR1 and Prohibitin1), as evidenced by qPCR. Cellular cytotoxicity experiments further confirm that this NP co-delivery strategy can drastically improve the sensitivity of drug-resistant cells to chemotherapy. In addition, these hybrid NPs demonstrate promising in vivo results for co-delivering siRNA and chemotherapeutic drugs to treat drug-resistant 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 2896. doi:1538-7445.AM2012-2896
Abstract 291: Vitamin D induces KDM6B/JMJD3 histone demethylase gene in human colorectal cancer cells
Authors: Pereira Fábio , Barbáchano Antonio , Silva Javier , Bonilla Félix , Campbell Moray , Muñoz Alberto , Larriba María Jesús 
Published: August 2012

Abstract
Epidemiological and preclinical studies have shown that the active vitamin D metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) has protective effects against colorectal cancer (CRC). Histone tails are subjected to a variety of post-translational modifications, including methylation, which play an important gene regulatory role in development and physiology. Misregulation of histone modifications alters gene expression and leads to perturbations of the cellular identity, which may contribute to cancer initiation, progression and/or metastasis. We have found that 1,25(OH)2D3 regulates the expression of JMJD3 gene (also known as KDM6B) that encodes for a histone H3 lysine 27 demethylase with an important gene regulatory role in development and physiology. 1,25(OH)2D3 induces JMJD3 RNA expression in a time- and dose-dependent manner, activates the JMJD3 gene promoter and increases the level of JMJD3 RNA in human cancer cells of colon, breast and skin origin. JMJD3 upregulation is strictly dependent on vitamin D receptor (VDR) expression and is abolished by the protein synthesis inhibitor cycloheximide. We have also shown that JMJD3 modulates the gene regulatory action of 1,25(OH)2D3. In SW480-ADH CRC cells, JMJD3 knockdown by short-hairpin RNA or expression of an inactive mutant JMJD3 fragment decreases the induction by 1,25(OH)2D3 of CYP24A1, CDH1/E-cadherin and CST5/cystatin D genes and of an epithelial adhesive phenotype. Moreover, JMJD3 knockdown upregulates the epithelial-mesenchymal transition inducers SNAI1, ZEB1 and ZEB2 and the mesenchymal markers FN1/fibronectin 1 and LEF1, while it downregulates the epithelial genes CDH1/E-cadherin, CLDN1/claudin-1 and CLDN7/claudin-7. Additionally, JMJD3 knockdown blunts the nuclear export of β-catenin and abolishes the inhibition of β-catenin transcriptional activity caused by 1,25(OH)2D3. In line with data in cultured cells, the expression level of JMJD3 RNA is lower in tumour than in normal tissue in 56% of the CRC patients studied and correlates directly with VDR and inversely with SNAI1 RNA expression. Together, our results indicate that an epigenetic gene coding for a histone demethylase such as JMJD3 is a VDR target that partially mediate the effects of 1,25(OH)2D3 on human CRC 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 291. doi:1538-7445.AM2012-291
Abstract 2910: Selenium nanoparticles suppress prostate LNCaP cancer cells growth through induced endogenous apoptosis
Authors: Bi Xiaolin , Kong Ling , Yuan Qing , Zhu Huari , Gao Xueyun 
Published: August 2012

Abstract
Prostate cancer has the highest incidence in all kinds of cancers in males.Recent reports suggest androgen receptor (AR) plays a critical role in prostate cancer development.The trace element Selenium is suggested having cancer prevention activity and used as food supplement. Here, we investigated inherent anticancer mechanisms of Selenium nanoparticles. We found Selenium nanoparticles inhibit growth of prostate LNCaP cancer cells partially through caspases mediated apoptosis. Selenium nanoparticles suppress transcriptional activity of androgen receptor via down-regulating its mRNA and protein expression. Moreover, Selenium nanoparticles activate Akt kinase by increasing its phosphorylation, promote Akt-dependent androgen receptor phosphorylation and Mdm2 regulated degradation through proteasome pathway. Together, we suggest Selenium nanoparticles suppress prostate cancer cells growth by disrupting androgen receptor, implicating a potential application in cancer treatment.
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 2910. doi:1538-7445.AM2012-2910
Abstract 2911: SAR125844: a potent and selective ATP-competitive inhibitor of MET kinase
Authors: Schio Laurent , Nemecek Conception , Ugolini Antonio , Wentzler Sylvie , Grapinet Sandrine , Khider Jean , Albert Eva , Dischamps Nathalie , Gay Frédéric , Sonnefraud Véronique , Bacqué Eric , Kenigsberg Mireille , Goulaouic Hélène , Dagallier Anne , Vallée François , Bonche Fabrice , Lengauer Christoph 
Published: August 2012

Abstract
The tyrosine kinase MET is a membrane receptor that is essential for embryonic development and wound healing in normal cells. Stimulation of MET by its natural ligand, the hepatocyte growth factor (HGF), induces cell proliferation, migration, and invasion. Abnormal MET activation (over-expression of MET protein, amplification or mutations of the MET gene) has been observed in multiple human cancer types. We report herein the discovery of a potent and selective small molecule inhibitor (SAR125844) with potential therapeutic application in cancer patients with deregulated MET-dependent malignancies. Our initial hit identification approach was based on the biochemical screen of an in-house kinase inhibitor biased library where a series of benzimidazole sulfonate derivatives were identified with sub-micromolar MET inhibition. In particular, the initial hit exhibited an IC50 of 140 nM vs MET but it also had strong affinity for CDK9 (IC50= 6 nM), a CDK isoform involved in gene transcription. Chemical modifications of the series to dial out CDK9 affinity and remove potential normal cell cytotoxicity led to a more selective derivative with IC50's of 80nM and 1355nM vs MET and CDK9 respectively. Further sub-structural exploration allowed us to identify a heteorocyclic moiety which was shown by X-ray data to specifically interact with Tyr1230 in a non active conformation of the protein. The resulting highly favourable U-shape mode of binding in MET of representative examples from these series (e.g. IC50= 1nM) was not tolerated in CDK9 (IC50 &gt; 10µM). Final multi-parametric medicinal chemistry optimisation led to SAR125844 with single digit nanomolar antiproliferative activity on MET-amplified cell lines. SAR125844 is highly selective for MET kinase in a panel of 275 kinases tested, with only 5 other protein kinases inhibited at IC50 values below 300 nM. This compound exhibits also satisfactory eADMET in vitro properties and has shown moderate total plasma clearance, large volume of distribution and moderate to long terminal elimination half-life in rats.
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 2911. doi:1538-7445.AM2012-2911
Abstract 2924: Constitutively active androgen receptor splice variants function independently of full-length androgen receptor in a cell-based model of castrate-resistant prostate cancer
Authors: Lonergan Peter E. , Nacusi Lucas P. , Schmidt Lucy J. , Regan Kevin M. , Ertem Furkan U. , Sun Zhifu , Boorjian Stephen A. , Tindall Donald J. 
Published: August 2012

Abstract
Recent studies suggest that progression to castrate-resistant prostate cancer (CRPC) is due to generation of androgen receptor (AR) splice variants, lacking the ligand binding domain. These AR variants originally identified in cell-based models of CRPC, have also been detected in benign and malignant human prostate tissue, with the highest levels observed in late state CRPC. The diversity and complexity of AR variants is well appreciated but not fully understood. Using RT-PCR we assessed the expression of a number of AR variants in cell-based models of both castrate-resistant and androgen-dependent prostate cancer. Several AR variants were expressed in both 22Rv1 and VCaP cells, but not in LNCaP cells. Coding sequences for AR variants were cloned into expression vectors and constitutive transcriptional activity was observed using a luciferase reporter assay. Augmented transcriptional activity of AR variants was observed in cells that express full-length AR, when full-length AR was silenced using shRNA targeting exons 7/8. This observation suggests the constitutive activity of AR variants may be independent of full-length AR. We profiled the AR variant transcriptome in 22Rv1 cells, using the Illumina HumanHT12 v4 whole-genome expression array platform. shRNA targeting exon 1 was used to silence all AR isoforms and shRNA targeting exons 7/8 was used to silence full-length AR. 5,256 genes were modulated by knocking down all AR isoforms and 5,086 genes were modulated by knocking down full-length AR. A total of 3,714 genes were common to both groups, leaving 1542 genes modulated by AR variants and 1372 modulated by full-length AR (p&lt;0.05). The represents a subset of genes differentially regulated by AR variants independently of full length AR. Aggregate function of multiple AR variants may confer a CRPC phenotype independent of full-length AR. Pathway analysis of these genes differentially regulated by AR variants may reveal potential targets for therapeutic intervention in patients who progress despite androgen deprivation or anti-androgen therapy. (Supported by NIH grants CA125747, CA091956 and CA121277, T.J. Martell Foundation and the Mayo Clinic Prostate Cancer SPORE).
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 2924. doi:1538-7445.AM2012-2924