bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 1504: Inhibition of RNA-dependent protein kinase (PKR) enhances radiation sensitivity in lung cancer cells
Authors: Pataer Abujiang , Lu Xiaolin , Roth Jack A. , Swisher Stephen G. 
Published: February 2011

Abstract
We have previously demonstrated that radiation resistance in MEFs is mediated in part through RNA-dependent protein kinase (PKR) possibly through upregulation of AKT and NFk-B. The role of PKR in cancer cells has not been evaluated. In this study, we show that the transduction of MEFs and lung cancer cells with adenoviral wt PKR results in nuclear translocation of PKR, activation of AKT1/2 and increased radiation resistance. The transduction of lung cancer cells or MEFs with a dominant negative adenoviral PKR vector blocks nuclear translocation of PKR, inhibits AKT activation and leads to the reversal of radiation resistance. Plasmid transduction of MEFs and lung cancer cells with nuclear targeted wt PKR vectors also results in AKT1/2 activation and increased radiation resistance. This effect is selectively abrogated by plasmid transduction of dominant negative PKR vectors which inhibit AKT1/2 activation and restore radiation sensitivity. These findings suggest a novel role for PKR in lung cancer cells as a mediator of radiation resistance possibly through translocation of the protein product to the nucleus and activation of AKT1/2.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1504.
Abstract 1506: Prodrug targeted gene therapy for colorectal cancer
Authors: Kusumanchi Praveen , Zhang Yonghua , Chakka Padma , Jayaram Nagesh H. , Khan Rehana , Antony Asok C. , Jayaram Hiremagalur N. 
Published: February 2011

Abstract
In the US colorectal cancer is the second and third most common cause of cancer death in men and women, respectively. The drawback of conventional therapy is its non-specificity and a median survival of only 10-15 months with the present combinations. Our studies with human colorectal cancer cell lines demonstrate a relationship between human nicotinamide mononucleotide adenylyltransferase-2 (hNMNAT-2) expression and cell kill with tiazofurin (TR) and benzamide riboside (BR). Thus, the purpose of the present study is to examine whether over-expressing hNMNAT-2 selectively confers sensitivity to TR and BR in human colorectal cancer cells that show resistance to TR and BR therapy.
TR and BR are pro-drugs that are metabolized by the action of NMNAT to its active form, TAD (thiazole-4-carboxamide adenine dinucleotide) and BAD (Benzamide adenine dinucleotide), respectively. TAD/BAD potently inhibit inosine-5’-monophosphate dehydrogenase (IMPDH) causing reduced guanylate synthesis resulting in cancer cell death. We achieved 2- to 5-fold increase in expression of hNMNAT-2 by transfecting colorectal cancer cells (Caco-2 and HT-29) with pTracerNMNAT-2 as demonstrated by Western blot and FACS. hNMNAT-2 transfected colorectal cancer cells exhibited a 3- to 7-fold increase in tumor-cell kill with TR and BR. hNMNAT-2 transfected cells did not exhibit modulation of either NAD levels or IMPDH expression.
Folate receptor alpha (FR-α) is overexpressed on the colorectal cancer cell surface to sequester available folate to promote cancer cell proliferation. Primary colorectal carcinomas which exhibit high FR-α overexpression also correlated with decreased 5-year survival. We demonstrated an upregulation of FR-α expression in human colorectal cancer cells (up to 10-fold) by adaptation to growth in physiological low folate medium resulting in 2- to 5-fold increase in colorectal cancer cell-kill with TR or BR encapsulated in folate-tethered liposomes. To translate in vitro studies to in vivo applicability, we are utilizing adeno-associated virus (AAV-2) to transduce hNMNAT-2 gene into colorectal cancers implanted in athymic mice. To achieve this goal, we engineered hNMNAT-2 gene into AAV-2 vector to increase efficiency of gene transfer, and encapsulated in folate-tethered liposomes to target colorectal cancer cells. The potential significance of these new proof-of principle studies is that they will set the stage for the next level of studies that could culminate in a new form of pro-drug targeted gene therapy for colorectal cancer with enhanced tumor cell-kill with little toxicity.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1506.
Abstract 1508: Development of a strategy to knock down SDF-1 using shRNA as a means to prevent pulmonary metastasis
Authors: Annan Anand C. , Preuss Meredith A. , Borovjagin Anton V. , Ugai Hideyo , Curiel David T. 
Published: February 2011

Abstract
Metastasis, a poor prognostic indicator causing increased mortality, occurs in an organ specific pattern with lungs and lymph nodes most commonly involved. Cancer cells expressing ‘CXC'-chemokine family Receptor-4 (CXCR4) are chemo-attracted to the pulmonary tissue expressing its cognate ligand Stromal Derived Factor-1 (SDF-1), which aid in formation of metastasis. In this regard, we propose to modulate this axis through knock down of SDF-1 specifically in pulmonary vasculature to prevent lung metastasis. Our laboratory has previously shown that human adenovirus (Ad), when injected via the tail vein into human Coxsackie Adenovirus Receptor (hCAR) transgenic mice, mice that ubiquitously express the hCAR native Ad receptor, transduces pulmonary vasculature preferentially. To this end, we plan to knock- down SDF-1 using shRNA against SDF-1 employing Ad as the vector to deliver them in vivo to achieve pulmonary targeting. To establish a pulmonary metastatic model in the “hCAR” mouse, we injected B16-F10 melanoma cells stably expressing CXCR4 (to cause metastasis) and firefly luciferase (to track tumor cells) via tail vein. Presence of lung metastasis was confirmed by histopathological analysis, immunohistochemistry for CXCR4 and luciferase assay of the tissues. In order to identify a shRNA to deliver to the pulmonary vasculature to decrease SDF-1, we evaluated several plasmid shRNAs for their ability to suppress SDF-1 expression at the mRNA level using qRT-PCR in vitro. From this experiment, we identified one shRNA which gave significant decrease in mRNA of SDF-1 measured by qRT-PCR (&gt;70%). We created an Ad vector expressing this particular shRNA and measured its efficiency of inhibiting SDF-1 expression of approximately 75% for mRNA by qRT-PCR and approximately 90% for protein by Western Blot. Future studies include demonstrating the functional knock-down of SDF-1 in vitro by transwell chamber assay and subsequently analyzing the biological effect of knocking down SDF-1 in vivo in the pulmonary metastatic model established in “hCAR” mouse. In conclusion, therapies available for prevention of metastasis are limited despite different treatment modalities available for cancer. Our approach of targeted knock down of SDF-1 would reduce the metastatic burden to the lungs with potential for clinical translation into a therapeutic approach to prevent lung metastasis.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1508.
Abstract 1513: Pre-clinical evaluation of two oncolytic viral vectors expressing IFNβ in treatment of thoracic cancer: Vaccinia virus versus vesicular stomatitis virus
Authors: Wang Liang-Chuan Steve , Saloura Valia , Alexander Edward , Cheng Guanjun , Kapoor Veena , Vile Richard , Thorne Stephen H. , Isaacs Stuart N. , Albelda Steven M. 
Published: February 2011

Abstract
Rationale: Given recent success in delivering interferon-beta (IFNβ) using replication incompetent adenovirus in patients with malignant pleural effusions, we hypothesized that vectors that could replicate (inducing oncolysis) and express IFNβ at high level would be more effective. Both vaccinia virus (VV) and vesicular stomatitis (VSV) expressing mouse IFNβ have been constructed in a manner to improve their safety and efficacy as oncolytic vectors. In this study, we evaluated these two oncolytic vectors in different murine thoracic cancer models for clinical translation.
Experimental procedures: We compared the efficacy of VVIFNβ and VSVIFNβ to kill 3 mouse lung cancer and 4 mouse mesothelioma lines in vitro over a 5 day-period assessing cell viability by MTT assay. The amount of IFNβ produced by these two vectors were measured with ELISA. The viral replication in infected mice was assessed by measuring viral titers in both immunocompetent and immunodeficient mice bearing an IFN-non-responsive AB12 tumor, following intratumoral injection of either vector at 108 pfu/mouse. To assess their anti-tumor activity, the two vectors were also given at 108 pfu/mouse intratumorally in mice bearing two lung cancer tumors on their flanks.
Results: The replication of VSVIFNβ and its killing ability was limited in some of the tumor lines. This appeared to be due to an intact IFN response pathway. In contrast, VVIFNβ was able to kill all of the tumor lines. In culture, VSV replicates faster than VV, which resulted in faster cell killing (in susceptible cell lines), but with less IFNβ production. The amount of IFNβ production by VVIFNβ was comparable with AdIFNβ over a 5 day period. VVIFNβ-infected immunodeficient mice showed minimal or no toxicity when given virus intravenously, while all 5 mice infected with VSVIFNβ developed neurotoxicity within a week. In the TC-1 lung cancer model, VVIFNβ caused tumor regression, while VSVIFNβ and AdIFNβ were completely ineffective. In a second model using LKRM2, all 3 viral vectors were equivalent. The anti-tumor effect of VVIFNβ was shown to be mainly CD8 dependant, as depletion of CD8 with antibody dampened the tumor growth inhibition from 48% to 20%.
Conclusions: Overall, VVIFNβ appears to be a better oncolytic vector than VSVIFNβ for a number of reasons: 1) it is safer, 2) it is able to replicate in vitro and in vivo in almost every cell line tested, 3) it induces longer and larger IFNβ production, and 4) it can potentially be given intravenously.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1513.
Abstract 1514: Oncolytic viral therapy for glioblastoma induces robust natural killer cell activation
Authors: Alvarez-Breckenridge Christopher A. , Yu Jianhua , Pradarelli Jason , Liu Tom , Kaur Balveen , Caligiuri Michael , Chiocca E. Antonio 
Published: February 2011

Abstract
Oncolytic viral (OV) therapy is a promising treatment being tested for safety and efficacy. Natural killer cells (NK) limit viral infections, and previous work suggests they may similarly attenuate virotherapy. We used flow cytometry to evaluate the temporal pattern of NK recruitment in intracranial tumors (U87DEGFR glioma) treated with the oncolytic herpes virus, rQnestin 34.5, or PBS. Quantification of NK recruitment into intracranial tumors treated with rQnestin34.5 or PBS revealed significant enrichment of these cells into the tumor hemisphere at early timepoints and continuing through 72 hours (2.2-fold, p=0.02) following infection. Moreover, NK cells recruited to the site of inoculation exhibited an activated phenotype, including enhanced CD69, CD62L, CD27, NKG2D, and CD127 staining compared to PBS treated mice. This robust NK response was demonstrated to be detrimental to OV efficacy through the enhanced survival of NK depleted mice treated with OV compared to OV treated mice containing NK cells (median survival 31.6 days compared to median survival 23.6 days, p=0.04). Since NK cells are recruited into the tumor microenvironment following infection, we postulated that OV infection of glioma cells was also activating NK cells. We measured granzyme B and IFNg production by NK cells in the presence of infected or uninfected glioma. Our results indicate that glioma mediated activation of NK cells was augmented by OV infection. Additionally, these findings were corroborated with increased NK killing of OV infected glioma compared to uninfected glioma. Due to the enhanced NK cytotoxic properties induced by OV infection, we proceeded to investigate the expression of NK activating ligands on the surface of infected glioma cells that could potentially mediate this effect. Focusing on ligands for NKG2D and the natural cytotoxicity receptors (NKp30, NKp44, and NKp46), viral infection of cultured gliomas was shown to upregulate ligand expression for NKG2D (24%, p=0.004), NKp46 (41%, p=0.01), and NKp30 (2.75-fold, p=0.001) while selectively downregulating ligand expression for NKp44 (2.8-fold, p=0.005). These findings suggest that viral infection of gliomas is altering the ligand signature for NK activation. Since NK cells possess both antiviral and antitumor properties, further work will investigate if virus induced NK activating signals can be selectively blocked in order to enhance viral efficacy while maintaining NK antitumor efficacy. This is the first study investigating the changes in NK cell activation and recruitment in gliomas upon oncolytic HSV-1 treatment.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1514.
Abstract 1516: In vivo tumor targeted delivery of siRNA by biodegradable nanoparticles
Authors: Woodle Martin C. , Scaria Puthupparampil , Liu Yijia , Spears Ryan , Zhang Betty Hongxue 
Published: February 2011

Abstract
We are developing synthetic, engineered, ElectroNanoPlex™ nanoparticles for tumor targeted in vivo delivery of siRNA, plasmids, and other nucleic acids. These nanoparticles employ biodegradable cationic polyamide macromolecules that form an electrostatic association with the anionic nucleic acid cargo, and provide a hydrophilic steric polymer coating on the surface of the nanoparticles. Conditions have been identified to form siRNA or plasmid carrying nanoparticles with a mean diameter of approximately 100 nm, which falls within the range appropriate for enhanced permeability and retention (EPR) localization in tumor tissue. We have successfully delivered nucleic acids in vivo to solid tumors using nanoparticles with the steric coating but without a ligand for specific targeting, suggesting a mechanism of action based on EPR targeting. These nanoparticles are being commercialized under the tradename InVivoPlex™ for tumor gene function research, and drug target validation, in murine xenograft tumor models. Compared to other in vivo delivery technologies these nanoparticles show vastly diminished expression of plasmid DNA in lung, spleen, liver and kidney. Also, plasmid DNA and siRNA oligonucleotides can be co-packaged and delivered together using these nanoparticles, permitting studies of simultaneous down-regulation and up-regulation of different genes. Active targeting to cell surface receptors or antigens may be employed by decorating the nanoparticle surface with peptides such as cyclic RGD or monoclonal antibodies. Studies of antibody-mediated tumor cell delivery by ligand decorated nanoparticles will be presented. These nanoparticle systems will advance tumor targeted research using siRNA and are expected to eventually enable therapeutic applications of siRNA, or other nucleic acid agents that are promising in light of their molecular biological properties but currently face daunting pharmaceutical delivery challenges.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1516.
Abstract 1517: Wnt signaling pathway seems a better target than k-ras pathway for colon cancer specific suicide gene therapy
Authors: Teimoori-Toolabi Ladan , Azadmanesh Kayhan , Zeianli Sirous , Kaviani Ahmad , Kia Zahra Noorayee , Ghaffarpoor Leyli , Khandan Manijeh 
Published: February 2011

Abstract
As Wnt and K-ras are two most important signaling pathways activated in colon cancer, exploiting them for colon cancer specific gene therapy seems an attractive biological approach for therapy of colon cancer. Our aim was inserting specific promoters downstream to these pathways upstream of suicide genes. Therefore we investigated promoters downstream to these signaling pathways in order to insert them upstream of suicide genes. These promoters should be specifically upregulated by these pathways. They should have been proved to be inactive in normal cells of the body. These promoters should also be short enough to be inserted upstream of a therapeutic gene in a gene therapy construct. After investigating we found out Fibroblast Growth factor 18 (FGF18) and Urokinase Plasminogen Activator Receptor (UPAR) promoters which met the above mentioned criteria and seemed to be the most plausible promoters downstream to Wnt and K-ras signaling pathways. We inserted the most important parts of these promoters upstream of β-Gal as reporter and thymidine kinase as suicide genes. The activity of these promoters in two distinct colon cancer cell lines (HCT116 and SW480) and normal colon cells was studied. It was showed that FGF18 and UPAR promoter activity in HCT116 cell line was 0.25 and 0.187 times in comparison to CMV promoter while in SW480 this ratio was 0.09 and 0.02. Neither of promoters was active in normal colon cells. After applying the specific suicidal constructs in colon cancer cells, it was showed that both suicidal constructs reduced the viability of HCT116 in the presence of 20µg/ml of ganciclovir while in SW480 UPAR and FGF18 promoters reduced the viability in the presence of 40µg/ml and 20µg/ml ganciclovir respectively. The positive control suicidal construct induced significant reduction in the viability of both cell lines in the presence of 20µg/ml ganciclovir. The apoptosis induced by these suicidal constructs was also proved by M30cytodeath antibody in HCT116 and Annexin-PI in SW480. This difference in the method of proving apoptosis might be due to different mechanism of induced cell death by phosphorylated ganciclovir. These experiments showed that exploiting specific promoters downstream to activated signaling pathways in cancerous cells would be a good strategy for specific expression of therapeutic genes in cancerous cells. Also in colon cancer exploiting universal pathways such as wnt might be a better investment for this approach.
Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1517.
Abstract 1518: P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2) limit sunitinib brain accumulation which can be enhanced by oral elacridar treatment
Authors: Tang Seng Chuan , Lagas Jurjen S. , Lankheet Nienke , Rosing Hilde , Beijnen Jos H. , Schinkel Alfred H. 
Published: February 2011

Abstract
Sunitinib malate is an orally active, multi-targeted receptor tyrosine kinase inhibitor, which has been used as a standard treatment for metastatic renal cell carcinoma. However, the efficacy of sunitinib in patients with brain metastases has not been extensively explored. The purpose of this study was to investigate the individual and combined roles of ABCB1 and ABCG2 in sunitinib brain accumulation. Active transport of sunitinib was assessed in Madin-Darby canine kidney cells and its subclones expressing human ABCB1 and murine ABCG2. Sunitinib was found to be a good substrate of murine ABCG2 and moderate substrate of human ABCB1. In cells transfected with murine ABCG2 and human ABCB1, transport of sunitinib was markedly increased, resulting in 14.4-fold and 2.4-fold higher transport ratios compared to parental cells, respectively. To establish the roles of ABCB1 and ABCG2 in the pharmacokinetics and brain accumulation of sunitinib, sunitinib malate (10 mg/kg) was administered orally to wild-type, Abcb1a/1b−/−, Abcg2−/− and Abcb1a/1b;Abcg2−/− mice. Bioavailability of sunitinib after oral administration was not restricted by ABCB1 and/or ABCG2. Furthermore, sunitinib brain accumulation, 1 hour after sunitinib administration was not affected by single ABCB1 or ABCG2 deficiency. However, the brain penetration of orally administered sunitinib was 9.8-fold increased in Abcb1a/1b;Abcg2−/− mice compared to wild-type mice. In addition, brain-to-plasma ratios were significantly increased in Abcb1a/1b−/− knockout mice (2.6-fold) and Abcb1a/1b;Abcg2−/− mice (18.2-fold), but not altered in single Abcg2−/− knockout mice. To test the hypothesis that the dual ABCB1 and ABCG2 inhibitor elacridar could enhance brain penetration of sunitinib, we orally coadministered elacridar (100 mg/kg) and sunitinib malate (10 mg/kg) to wild-type and Abcb1a/1b;Abcg2−/− mice. Sunitinib brain concentration and brain-to-plasma ratio in wild-type mice were significantly increased by 12-fold and 12.7-fold, respectively, compared to wild-type mice without elacridar treatment, and these values were very similar to those observed for Abcb1a/1b;Abcg2−/− mice. In conclusion, sunitinib is transported in vitro and in vivo by ABCB1 and ABCG2, with ABCB1 being the more important factor in limiting sunitinib distribution into the brain in mice. Our results suggest that coadministration of oral elacridar with sunitinib might improve therapeutic efficacy in cancer patients with brain metastases.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1518.