bluuebunny/crossref_metadata_2025 huggingface dataset:
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

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

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.
Abstract 1520: CDX2 regulates Multidrug Resistance 1 gene expression in malignant intestinal epithelium
Authors: Takakura Yuji , Hinoi Takao , Oue Naohide , Sasada Tatsunari , Kawaguchi Yasuo , Okajima Masazumi , Yasui Wataru , Ohdan Hideki
Published: February 2011

The intestine-specific caudal-related homeobox transcription factor CDX2 is important for intestinal development and differentiation. CDX2 heterozygous mice form colonic polyps, and loss of CDX2 expression is seen in some poorly differentiated colon carcinoma in humans. Conversely, ectopic CDX2 expression in the stomach of transgenic mice promotes intestinal metaplasia, and CDX2 expression is often seen in stomach and esophageal metaplasia. We sought to define CDX2-regulated genes to enhance the knowledge of CDX2 function. HT-29 colorectal cancer cells with minimal endogenous CDX2 expression were generated to express exogenous CDX2, and the gene expression changes were assessed by microarrays. Activation of CDX2 rapidly induced Multidrug Resistance 1 (MDR1/P-glycoprotein/ABCB1) gene expression in HT-29 cells, even in the presence of protein synthesis inhibitor, and RNA interference-mediated inhibition of CDX2 decreased MDR1 expression. In other colorectal cancer cell lines and human tissues, endogenous MDR1 expression was well correlated to CDX2 expression. Analysis with MDR1 reporter gene constructs and chromatin-immunoprecipitation assays suggested that CDX2 directly regulates MDR1 transcription. Overexpression of CDX2 in HT-29 cells revealed increased resistance to MDR1's known substrate, vincristine and paclitaxel, which was reversed by an MDR1 inhibitor, verapamil. These data indicate that CDX2 directly regulates MDR1 gene expression via binding to elements in the promoter region. Thus, CDX2 is probably important for basal expression of MDR1, regulating drug excretion and absorption in the lower gastrointestinal tract, as well as for multidrug resistance to chemotherapy reagent in CDX2-positive gastrointestinal cancers.

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 1520.
Abstract 1531: BCR-Abl tyrosine kinase inhibitor Nilotinib (Tasigna®) reverses ABCB1/Pgp- and ABCG2/BCRP-mediated multidrug resistance
Authors: Tiwari Amit K. , Sodani Kamlesh , Wang Sirong , Kuang Ye-Hong , Deng Wen , Chen Xiang , Chen Kevin , Ashby Charles R. , Chen Zhe-Sheng
Published: February 2011

Over-expression of ABC transporters are involved in the extrusion of therapeutic drugs, leading to MDR, which can eventually produce cancer chemotherapy failure. Previously, it was shown that specific TKIs could modulate several human multidrug resistance (MDR) ATP-binding cassette (ABC) proteins. Recently discovered second generation, BCR-Abl tyrosine kinase inhibitor (TKI), Nilotinib was developed to surmount resistance or intolerance to imatinib in patients with Philadelphia positive chronic myelogenous leukemia. Here, we report for the first time that nilotinib not only potentiates the cytotoxicity of widely used therapeutic substrates of ABCB1, such as colchicine, vincristine, and paclitaxel, but also that of ABCG2 substrates such as mitoxantrone and doxorubicin. Nilotinib also significantly enhances the intracellular accumulation of methotrexate (MTX) in cells transfected with ABCG2. Similarly, nilotinib significantly increases the accumulation of paclitaxel in cell lines overexpressing ABCB1. Furthermore, nilotinib produces a concentration-dependent inhibition of the ABCG2-mediated transport of MTX, as well as E217βG a physiological substrate of ABCG2. Uptake studies in membrane vesicles over-expressing ABCG2 have indicated that nilotinib inhibits ABCG2 similar to other established TKIs as well as fumitremorgin C. In addition, the kinetic analysis demonstrated that nilotinib is a potent competitive inhibitor of MTX transport by ABCG2 with a Ki value of 0.69+/-0.083 μM. To sum it up, our results indicate that nilotinib could reverse ABCB1- and ABCG2-mediated MDR by blocking the efflux function of these transporters. These findings may be useful in clinical practice for cancer combination therapy with nilotinib and may be vital to the design of present and future clinical trials with nilotinib, elucidating potential pharmacokinetic interactions.

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 1531.
Abstract 1532: Stemofoline is a potent natural product modulator of the multidrug resistance-linked P-glycoprotein (ABCB1)
Authors: Ohnuma Shinobu , Chanmahasathien Wisinee , Ambudkar Suresh V. , Limtrakul Pornngarm
Published: February 2011

Stemofoline is a plant alkaloid isolated from Stemona, which is native to Eastern and Southeastern Asia and Northern Australasia. The extract from the tuberous roots of Stemona is used to treat respiratory disorders, including pulmonary tuberculosis and bronchitis, and different insect pests. P-glycoprotein (P-gp, ABCB1), a member of the ATP-binding cassette (ABC) transporter superfamily is implicated in multidrug resistance (MDR) in cancer cells. We investigated the effect of stemofoline on P-gp function aiming to overcome P-gp-mediated MDR. Stemofoline stimulated P-gp-mediated ATP hydrolysis (conc. required for 50% stimulation = 10-12 micro M). In addition, Stemofoline did not change the Km for ATP, suggesting that this alkaloid seems to interact with drug-binding site of P-gp. Consistent with this view, stemofoline inhibited the photo-crosslinking of P-gp with [125I]-iodoarylazidoprazosin (IAAP; IC 50 = 7 micro M), which is a transport substrate of P-gp. Interestingly, stemofoline instead of inhibiting substrate-stimulated ATP hydrolysis (such as verapamil and vinblastine), it further enhanced the ATPase activity suggesting that stemofoline and these drugs (verapamil and vinblasine) bind simultaneously to P-gp in the drug-binding pocket. In addition, the efflux of the fluorescent substrates such as calcein-AM and Bodipy-verapamil from P-gp expressing cells was blocked by stemofoline in a concentration-dependent manner. Furthermore, stemofoline was not cytotoxic to P-gp expressing KB-V1 or parental KB-3-1 cells up to 100 micro M concentration, but this compound at non-toxic concentration (1 − 5 micro M) sensitized KB-V1 cells to vinblastine. Stemofoline does not appear to interact with ABCG2 transporter, which is also linked to development of MDR. These studies indicate that stemofoline could be developed as a specific potent modulator to overcome P-gp-mediated MDR in cancer cells.

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 1532.
Abstract 1536: Characterization of tumor cell lines selected for resistance to the HDM2 antagonist Nutlin-3a
Authors: Wang Yaolin , Wang Xiaoying , Lipari Philip , Devlin David , Simon Jason , Chen Lei , Levitane Diane , Liu Suxing , Seidel-Dugan Cynthia , Hicklin Daniel J. , Bishop Walter Robert
Published: February 2011

The tumor suppressor p53 is activated in response to various cellular stress signals including DNA damage and oncogene activation. Activated p53 regulates the expression of multiple downstream target genes involved in cell cycle control, cell death and senescence. Dysfunction of the p53 pathway is the most frequent alteration in human cancers. HDM2 protein binds directly to p53 and acts as a major negative regulator of the p53 function. Nutlin-3a is an antagonist of the HDM2-p53 protein-protein interaction and restores p53 pathway function in tumors with wild-type p53. Nutlin-3a demonstrates anti-tumor activity both in vitro and in vivo. Emergence of resistance is frequently observed with many anti-cancer therapeutics. The goal of the current studies is to understand the mechanism of resistance to Nutlin-3a. Cancer cell lines were treated with Nutlin-3a for an extended period and resistant clones were isolated. We found using molecular profiling studies that the emergence of Nutlin resistance is primarily due to the inactivation of the p53 signaling pathway through either mutation of the p53 gene or loss of p53 protein expression. These Nutlin-resistant cells are also resistant to others antagonists of the HDM2-p53 protein-protein interaction. These results suggest that, following chronic treatment, resistance to HDM2 antagonists may occur in the clinic. It will be important to combine HDM2 antagonists with other anti-cancer drugs early on during the treatment cycle in order to minimize the emergence of resistance.

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 1536.
Abstract 1539: Lovastatin sensitizes tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis through inactivation of NF-kB pathway and activation of JNK/p38 pathway in human glioblastoma cells
Authors: Liu Pi-chu , Li Jun , Chen George G. , Lu Gang , Poon Wai S.
Published: February 2011

Glioblastoma (GBM) is among the deadliest of all human cancers. Tumor Necrosis Factor-Related Apoptosis Inducing Ligand (TRAIL) becomes a promising candidate for GBM therapy, not only for its strong antitumor activity in a wide range of cancer cell types, but also for its minimal cytotoxity to most normal cells. The main barrier in TRAIL-based therapies, however, is TRAIL resistance (including GBM-derived cell lines and primary cells). Methods overcome TRAIL resistance can largely enhance the effect of TRAIL-based therapy. In this regard, we have reported that lovastatin could sensitize GBM cells to TRAIL, but the underlying mechanism remains largely unknown. Our data suggested that lovastatin could up-regulate DR5 (TRAIL-R2) expression, which might contribute to the sensitization of GBM cells to TRAIL by lovastatin. Here we provide preliminary results suggesting that the mitogen-activated protein kinase (MAPK) signaling (p<0.001) was significantly dysregulated after lovastatin treatment, by microarray pathway analysis in three GBM cell lines (A172, M059J and M059K). Furthermore, we demonstrated that lovastatin sensitized GBM cells to TRAIL by inhibiting ERK/MAPK and activating JNK/p38. In addition, NF-kB was reported to be involved in DR5 regulation. In this study, we further characterized the role of NF-kB signaling in TRAIL resistant GBM cell sensitization by lovastatin and especially its relation to TRAIL receptors. We have extended our study to investigate the mechanism of lovastatin sensitizing GBM cells to TRAIL. We first showed that lovastatin down-regulaetd cRelA/p65, one of the components of NF-κB subunit, which was reported to suppress DR-5 expression. This finding suggested that lovastatin might sensitize GBM cells to TRAIL by cRelA/p65 inactivation. Moreover, we found that the inactivation of cRelA/p65 was through down-regulation of its inhibitory IκB protein degradation and IKKα/ β after lovastatin treatment. In addition, we found that inhibition of NF-κB up-regulated DR5 expression. Findings obtained not only provides new insights into TRAIL resistant death signaling via both intrinsic and extrinsic pathways, but also is essential for developing new target-specific and safe strategy to overcome TRAIL resistance for future clinical application.

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 1539.
Abstract 1546: Effective co-targeting of tumor and tumor stroma for head and neck cancer treatment: making the right combination
Authors: Xing Rosie Hongmei , Wu Yongfei , Zhang Qingbei , Huang Yong , Shen Jikun , Fan Hanli , Li Jianrong , Xiao Hongyan , Lee Younghee , Weichselbaum Ralph , Lingen Mark , Lussier Yves A.
Published: February 2011

Successful cancer management has been hindered by the development of inherent or acquired resistance. Increasing evidence suggest that manifestation of comparable resistance phenotype may arise from different combinations of molecular lesions. Signal transduction pathways in cancer cells exhibit remarkable flexibility for re-wiring such that cancer cells of solid tumors are able of altering the targeting receptor tyrosine kinases (RTKs) such as EGFR, or using unaffected and co-expressed RTKs signaling, or manifesting gain-of-function changes of the downstream signaling molecules to sustain tumor growth and progression. However, The potential of a “pathway rewiring” strategy to more efficiently target a deregulated signaling network has not been effectively explored due to the lack of scientific framework. Furthermore, the effort of developing effective agents or combinations that can effectively co-target both cancer cells and tumor stroma is lagging behind the therapeutic development aiming at cancer cell targeting. In this report, we demonstrate the effectiveness of integrating predicative pathway analysis to identify mTOR as a key interacting signaling target for developing a rational “pathway-based” combination to overcome resistance to anti-EGFR therapies in squamous carcinoma of the head and neck (HNC). We show for the first time that HNC cancer cells can effectively exploit the molecular interactions between EGFR and mTOR to confer reciprocal resistance. In addition, network modeling and comparison of xenograft with human tumor specimens identifies the abundant presence of myofibroblasts specifically associated with cancer state. We subsequently show the dependence of the clonogenic survival of myofibroblast cells on mTOR signaling in vitro. In vivo, only concomitant inhibition of EGFR and mTOR signaling via erlotinib and rapamycin, respectively, achieves effective differential and co-targeting of cancer cells and myofibroblast and endothelial cell functions in tumor stroma, leading to tumor regression. Thus, we show a systems’ approach-guided biological investigation has the potential to identify resistance mechanisms that can be explored to design more effective combinations of targeted therapies capable of overcoming resistance via “pathway rewiring” and achieving tumor-tumor stroma co-targeting. Based on these observations, an NIH funded network Phase II human clinical trial, lead by the University of Chicago Cancer Center, is soon underway to evaluate the therapeutic efficacy of this combination therapy.

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 1546.
Abstract 1547: Acquisition of resistance to the β1 integrin antagonist HYD1 correlates with decreased α4, α6, αV and β1 integrin expression and decreased adhesion to fibronectin, VCAM-1 and vitronectin
Authors: Emmons Michael , Nair Rajesh , McLaughlin Mark , Eschrich Steven , Cress Anne , Hazlehurst Lori
Published: February 2011

Our laboratory recently reported that the D amino acid-containing β1 integrin inhibitory peptide HYD1 causes caspase independent cell death in multiple myeloma (MM) cell lines as a single agent in vitro and in vivo (Nair et al Molecular Cancer Therapeutics, 2009). Exposure of MM cells to HYD1 induces autophagy, but autophagy was shown to contribute to survival following HYD1 treatment. HYD1 treatment induces cell death in MM cell lines indicative of necrosis. These characteristics included: (a) an increase in the levels of reactive oxygen species (ROS), (b) ATP depletion and (c) loss of mitochondrial membrane potential. To further characterize the mechanism of HYD1 induced cell death an isogenic drug resistant variant was developed. This variant, referred to as H929-60, was developed by chronically exposing parental H929 cells to increasing doses of HYD1. Acquired resistance correlated with decreased HYD1 induced TO-PRO-3 positivity, decreased levels of ROS, reduced ATP depletion and reduced mmp loss compared to the H929 cell line. Additionally, the drug resistant variant H929-60 cells displayed decreased cell surface binding of FAM-HYD1 compared to H929 cells. These data indicate that decreased expression of the binding target(s) of HYD1 may contribute to drug resistance. Gene expression profiling (GEP) was used as an unbiased approach to identify changes in gene expression that may contribute to HYD1 resistance. Differentially expressed genes were mined in silico using the pathway analysis programs Ingenuity and GeneGo. The integrin signaling hub showed substantial changes in gene expression in the drug resistant variant compared to the parental cell line. Specifically, α4, α6, αV and β1 integrins were all down regulated along with the integrin associated protein CD47 in the HYD1 resistant cell line. These changes were consistent with decreased protein expression of integrins on the cell membrane and decreased functional adhesion to fibronectin, vitronectin and VCAM-1. Reducing the expression of α4 integrin using shRNA in the parental H929 cell line conferred partial resistance to HYD1 induced cell death. Together our data show that the acquisition of resistance to HYD1 correlated with decreased integrin expression and functional binding to extracellular matrixes. Future studies aim to determine whether a decrease in α6, αV and β1 integrins on the cell surface contributes to HYD1 resistance.

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 1547.
Abstract 1549: Oral inhibitors of macrophage migratory inhibitory factor (MIF) lead to reduced tumor burden in a murine model of invasive bladder cancer
Authors: Taylor John A. , Choudhary Shilpa , Hegde Poornima , Voznesensky Olga , de la Cruz Vidal F. , Pruitt James R. , Sielecki Thais M. , Pilbeam Carol
Published: February 2011

INTRODUCTION AND OBJECTIVES: MIF is a proinflammatory cytokine with regulatory properties over tumor suppressor proteins involved in bladder cancer. We have reported that absence of MIF in transgenic mice leads to decreased angiogenesis and invasion in the BBN model of bladder cancer. We evaluated the impact of 2 oral inhibitors of MIF (Cytokine PharmaSciences, King of Prussia, PA; CPSI) in the BBN model.

METHODS: 30, 3 mnth old male C57Bl/6 mice were treated with BBN 0.05% in drinking water for 22 wks. Mice (n=10/grp) received vehicle (PEG 300, methylcelluose), oral inhibitor CPSI-2705 or CPSI-1306 daily (25 mg/kg) by gavage from wks 16-22, corresponding to time of progression from CIS to invasive disease as determined in previous experiments. Animals were inspected daily for general health with weights recorded weekly. Bladders were weighed, fixed and assessed for tumor stage, grade, burden and associated angiogenesis.

RESULTS: In general, the group receiving CPSI-1306 appeared healthier during drug treatment. There was a 16% weight loss from the start of gavage in the control group vs 10-11% in the drug groups. Two animals each from the control and CPSI-2705 group died prior to study completion. The majority of control animals had evidence of upper tract obstruction with less noted in CPSI 2705 and none in the 1306 group. Average bladder weights were 0.5 ± 0.5 gm, 0.3 ± 0.3 gm and 0.2 ± 0.2 gm for control, 2705 and 1306 respectively which approached statistical significance for control vs 1306 (log transf p=0.06). There was a higher proportion of pT3 disease in the control (80%) vs inhibitor groups (60%). Tumor burden was markedly diminished in the drug groups (81% cntrl vs 62% 2705 vs 59% 1306, involvement invasive disease) with some bladders in these arms having only focal areas of invasion. Tumor grade trended lower in the drug groups as well.

CONCLUSIONS: The use of MIF oral inhibitors CPSI 2705 and CPSI 1306 in the BBN bladder cancer model resulted in less weight loss, improved general health, decreased tumor burden with a trend toward lower stage, grade and tumor associated angiogenesis. The results of this experiment warrant larger studies to validate and expand these findings with a goal of development for clinical use.

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 1549.
Abstract 1551: Benzimidazole as novel therapeutic agent for metastatic prostate cancer
Authors: Chung Ivy , Barrows Courtney , Wilson Arianne , Rummel Nathan , Badaruddin Shaikh , Mizokami Atsushi , Banyard Jackie , Zetter Bruce
Published: February 2011

While prostate cancer is among the most treatable disease when the tumor stays confined to the prostate, the prognosis is generally poor for patients whose cancer metastasizes to distant organs. Current chemotherapy is relatively limited for metastatic prostate cancer, and thus there is a demand for more efficacious treatments. Here, we described a novel screen of a library containing approved drugs, for compounds that selectively target metastatic prostate cancer cells. We identified that benzimidazoles, widely used as anti-parasitic agents, exhibit preferential toxicity in two paired of human prostate cancer cells with different metastatic potential and in an aggressive rat prostate adenocarcinoma model but showed minimal cell kill on normal prostate epithelial cells. As these drugs are highly water-insoluble, we improved the systemic bioavailability in mice using a micelle preparation. Benzimidazoles significantly extend the lifespan of tumor metastases-bearing mice (% increased life span, ILS 40-60 range), without severe toxicity to the host. Notably, these anti-tumor effects are comparable if not more effective than paclitaxel (%ILS 30). The selective cytotoxicity to the metastatic cells is mediated partly by inhibition of the microtubulin polymerization, leading to mitotic arrest and subsequently cell death. These cytotoxic effects are also observed in cancer cells with paclitaxel or multi-drug resistance, both in vitro and in vivo. The benzimidazoles may possess significant anti-tumor effects and a good safety profile that are desired in the long term treatment of men with late-stage prostate cancer and failed both hormone-deprivation and taxane-based therapies.

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 1551.
Abstract 1559: Targeting the PH domain of Tiam-1 to inhibit breast cancer metastasis
Authors: Moses Sylvestor A. , Song Zuohe , Du-Cuny Lei , Powis Garth , Mash Eugene , Zhang Shuxing , Meuillet Emmanuelle J.
Published: February 2011

TIAM-1 (T-lymphoma invasion and metastasis-inducing protein-1) is a highly conserved guanine nucleotide exchange factor and contains an N-terminal pleckstrin homology domain (PHn) and a Dbl homology (DH)/C-terminal PH domain (PHc). While no crystal structure exists for the PHn of TIAM-1, the crystal structure of DH-PHc of TIAM-1 in complex with Rac-1 has been reported. TIAM-1 has been found to be over-expressed in breast, colon and prostate cancers. An increase in TIAM-1 expression has been shown to be associated with increased metastatic potential of breast cancer cell lines. TIAM-1 is thus an ideal PH domain drug target directly related to cancer progression, metastasis and patient survival. In this study, we have identified novel small molecule inhibitors targeting the phosphoinositide (PtdIns) lipid binding PHc domain of TIAM-1 in order to selectively inhibit cell migration and survival. Utilizing an In Silico screen of our internal and Maybridge library and the crystal structure of TIAM-1, we have found 29 compounds that bind to PHc TIAM-1. In vitro assays have revealed that compound PH-210 and #10 significantly reduced the amount of active Rac1 and binds to PHc-TIAM-1 with high affinity (KD in the micromolar range) using surface plasmon resonance (SPR) spectrometry. Both compounds displace PtdIns-3,4,5-P3 in a SPR competitive binding assay. Ongoing in vivo studies using MDA-231 breast cancer cell lines will determine the anti-tumor activity of these compounds. Overall, these novel compounds could exhibit the ability to significantly reduce breast cancer metastasis by binding to PHc-TIAM-1 and could have the potential to be used with other chemotherapeutic compounds as part of an effective breast cancer treatment regimen.

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 1559.
Abstract 1562: PYK2 and FAK in breast cancer
Authors: Zhai Ling , Li Rongbao , Qu Zhican
Published: February 2011

Proliferation and invasion of malignant tumor cells are mediated by multiple events, including activation of focal adhesion signalings and cytoskeleton remodeling. Focal adhesion kinase (FAK) and proline-rich tyrosine kinase 2 (Pyk2) are cytoplasmic tyrosine kinases identified as key mediators in regulation of cytoskeleton proteins in focal adhesion. Pyk2 were found to be overexpressed in Glioblastoma and played a central role in brain tumor invasion. Studies also showed that FAK increased expression and activation in various human cancers. Recently, studies with patients’ tumor samples have demonstrated that Pyk2 and FAK are co-overexpressed in over 70% human breast cancers from the very early disease stage of in situ carcinoma to the advanced metastatic stage. Pyk2 was also involved in the cytoskeleton changes initiated by heregulin through the ErbB-2 receptor in breast cancer cell lines. To further investigate role of Pyk2 and FAK in breast cancer progression and metastasis, we studied protein expression and activation of Pyk2 and FAK, as well as their substrates and interacting proteins in human breast cancer and normal breast epithelial cell lines. Our results showed that activation of both Pyk2 and FAK are marked increased in breast cancer cell lines in comparison with normal breast epithelial cells. In addition, serum stimulation was able to further activate Pyk2 and FAK and to increase tyrosine phosphorylation of their substrates and interacting proteins, including paxillin, Src, and p130CAS. The activated Pyk2 and FAK formed protein complex with paxillin, Src, and p130CAS. Our results and other published studies support the cooperative function of Pyk2 and FAK in breast cancer progression and suggest that dual inhibition of Pyk2 and FAK is a potential therapeutic approach for invasive breast cancer. Lead compounds of Pyk2 and FAK inhibitors have been identified by Southern Research drug discovery team and will be further evaluated in vitro and in vivo as potential breast cancer 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 1562.
Abstract 1566: Effects of VEGFR-3 phosphorylation inhibitor on lymph node metastasis in diffuse-type gastric carcinoma
Authors: Yashiro Masakazu , Shinto Osamu , Kato Yukihiro , Kashiwagi Shinichiro , Fuyuhiro Yuhiko , Matsuoka Junko , Doi Yosuke , Noda Satoru , Morimoto Junya , Yamazoe Sadaaki , Matsuoka Tasuku , Tanaka Hiroaki , Ohira Masaichi , Sawada Tetsuji , Hirakawa Kosei
Published: February 2011

Background: Vascular endothelial growth factor receptor-3 (VEGFR-3) signaling mediates lymphangiogenesis and lymphatic invasion, however the effect of VEGFR-3 inhibition on the lymph node (LN) metastasis remains unclear. The aim of this study is to clarify the benefit of a VEGFR-3 inhibitor Ki23057 for LN metastasis.

Methods: Ki23057 was administered orally to gastric cancer models created by orthotopic inoculation of diffuse-type gastric cancer cells, OCUM-2MLN. Effects of Ki23057 on lymphatic vessel invasion, lymphatic vessel density, and VEGFR-3 phosphorylation were examined by immunostaining or immunoblotting.

Results: Ki23057 inhibited the autophosphorylation of VEGFR-3 with IC50 values of 4.3 nM in the cell-free kinase assay. Murine gastric cancer models created by the orthotopic inoculation of OCUM-2MLN cells showed the diffusely infiltrating growth and frequently developed LN metastasis. The oral administration of Ki23057 significantly (p<0.01) reduced the size of orthotopic tumors and the number of the metastatic LN in gastric cancer models. The degree of lymphatic invasion and lymphangiogenesis was significantly (p<0.05) lower in the gastric tumors treated by Ki23057. Ki23057 inhibited the phosphorylation of VEGFR-3 of lymphatic endothelial cells in gastric tumors.

Conclusion: The inhibition of lymphangiogenesis targeting VEGFR-3 phosphorylation is a therapeutic strategy for inhibiting LN metastasis of diffuse-type gastric cancer.

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 1566.
Abstract 1567: The multi-targeted kinase inhibitor Sunitinib blocks VEGF-C signaling pathway and lymphangiogenesis
Authors: Yasuo Kodera , Katanasaka Yasufumi , Kitamura Yuuka , Tamura Tomohide , Koizumi Fumiaki
Published: February 2011

Metastasis is the main cause of therapeutic failure and death in cancer patient. Tumor cells disseminate to distant organs through lymphatic and blood vessels. The degree of metastasis in regional lymph nodes is a prognostic factor and determines treatment course of patients.

Vascular endothelial growth factor (VEGF) and VEGF receptor (VEGFR) family regulate angiogenesis and lymphangiogenesis. Several clinical studies have shown that the expression of VEGF-C is associated with lymphangiogenesis and lymph node metastasis in many different types of cancer.

Sunitinib is a tyrosine kinase inhibitor that inhibits VEGFR, PDGFR, KIT, FLT3, RET, and CSF1R. The main mechanism for tumor growth inhibition is thought to be anti-angiogenic effect by inhibiting VEGFR-2 kinase activity. However, the effect of sunitinib on VEGF-C/VEGFR-3 pathway and lymphangiogenesis remain unclear.

Therefore, we evaluated the effect of sunitinib on lymphangiogenesis with using lymphatic endothelial cell (LEC) and imaging breast cancer model. Sunitinib inhibited VEGF-C-induced phosphorylation of VEGFR-3, Akt and ERK1/2 at submicromolar level in LEC. Additionally, the growth and tube formation were also blocked by sunitinib. Furthermore, sunitinib treatment significantly suppressed tumor lymphangiogenesis and axillary lymph node metastasis as evaluated by photon counting method.

These results suggest that Sunitinib may be beneficial for breast cancer patients by inhibiting lymph node 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 1567.
Abstract 1574: The impact of human wild type EGFR on lung tumorigenesis and in vivo sensitivity to EGFR-targeted therapies
Authors: Chen Liang , Ercan Dalia , Cho Jeonghee , Janne Pasi A. , Meyerson Matthew L. , Wong Kwok-Kin
Published: February 2011

Lung cancer is the leading cause of the cancer related death in the world. Non-small cell lung cancer is the major lung cancer type, of which more than 1.4 million new cases were diagnosed each year. Overexpression of wild type EGFR is common in NSCLC. However, it is not clear whether or not overexpression of wt EGFR is tumorigenic. We recently showed that overexpression of wt-hEGFR is capable of transforming cell lines. More importantly, inducible double transgenic mice overexpressing wt-hEGFR in lung epithelial compartment developed poorly differentiated lung adenocarcinoma and that the maintenance of the tumor is dependent on continuous functioning of wt-hEGFR. The tumor driven by overexpression of wt-hEGFR responds to cetuximab and erlotinib treatment.

These data suggest that a subpopulation of the lung cancer may be caused by overexpression of wt-hEGFR and that these lung cancers can be treated with anti-EGFR antibodies and EGFR tyrosine kinase inhibitors.

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 1574.
Abstract 1575: Bortezomib selectively induces apoptosis in hematological malignant cells through down-regulation of phospho-Akt independent of its proteasome inhibitory activity
Authors: Liu Chun-Yu , Shiau Chung-Wai , Cheng Ann-Lii , Kuo Hsin-Yu , Tzeng Cheng-Hwai , Chen Kuen-Feng
Published: February 2011

Background: Bortezomib, a proteasome inhibitor (PI), has excellent clinical activity in patients with multiple myeloma and mantle cell lymphoma. Our previous study has shown that down-regulation of phospho-Akt (P-Akt) plays a key role in determining the sensitivity of hepatocellular carcinoma cells to bortezomib-induced apoptosis. (Cancer Res, 2008). Here, we further examined whether P-Akt is associated with the drug sensitivity of hematological malignant cells toward bortezomib. Methods: Several hematological malignant cell lines were used for in vitro studies. Apoptosis was examined by both flow cytometry and Western blot. Signal transduction pathways in cells were assessed by Western Blot. Gene silencing was done by small interference RNA (siRNA). Results: Bortezomib induced apoptosis in association with down-regulation of P-Akt in a dose- and time-dependent manner in sensitive cells (HL-60) but not in resistant K562 cells. Down-regulation of Akt1 by small interference RNA overcame the apoptotic resistance to bortezomib in K562 cells whereas a constitutively activated Akt1 protected HL-60 cells from bortezomib-induced apoptosis. Importantly, bortezomib showed the similar inhibition of the proteasome activity in both sensitive and resistant cells, suggesting that bortezomib-induced apoptotic effect may not depend on its proteasome inhibitory effect. Conclusions: Down-regulation of P-Akt plays an important role in bortezomib-induced apoptosis in hematological malignancies. Targeting on Akt signaling, either directly or through upstream regulation, provides an attractive approach to overcome bortezomib resistance in certain hematological malignancies. Supported by VGHTPE 99DHA0100332

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 1575.
Abstract 1579: Depletion of GAPDH promotes p53 signaling, cell senescence and altered response to chemotherapeutic agents in human carcinoma cells
Authors: Phadke Manali S. , Krynetskaia Natalia , Krynetskiy Evgeny
Published: February 2011

Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is a pivotal enzyme of the glycolytic pathway; it also plays a role of a signaling/regulator molecule in several cellular networks. In this study, we used human lung carcinoma A549 and renal carcinoma UO-31 cell lines to elucidate the role of GAPDH in cell proliferation and cellular response to genotoxic drugs. Using RNA interference technology, we decreased GAPDH protein level 4-5-fold in A549 cells, and 2-3-fold in UO-31 cells. Depletion of GAPDH in cultured cells blocked cell cycle progression in G1 phase, and induced activation of p53 and accumulation of p21. Simultaneously, GAPDH-depleted cells manifested biomarkers of senescence as revealed by morphological changes and induction of SA-β-galactosidase activity. Inhibition of GAPDH synthesis in human carcinoma cells resulted in 3-4-fold ATP depletion, and induced cell growth arrest without AMPK phosphorylation. In contrast, inhibition of glycolysis by 2-deoxyglucose treatment resulted in decreased ATP level and AMPK phosphorylation but did not induce cell senescence. These results suggest that GAPDH depletion in A549 cell line activates p53 independently of AMPK activation, and mediates the induction of signaling pathways leading to senescence. Importantly, GAPDH knockdown in p53-proficient A549 and UO-31 cells resulted in 3-50-fold decreased cytotoxicity of antimetabolite drugs including deoxy-thioguanosine, cladribine, fluoro-ribouridine, fluoruracil, 2-chloroadenosine, mercaptopurine, azacytidine and cytarabine. The results of this study indicate that cytotoxic activity of antimetabolite nucleoside analogs is modulated by the status of GAPDH in the cancer cells. Cell senescence induced by depletion of GAPDH is a plausible mechanism of cell resistance to antimetabolites, a hypothesis being under investigation in our lab. In addition, our data indicate that GAPDH-depleting agents could be promising cytostatic drugs.

This work was supported by NCI grant R01 CA104729

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 1579.
Abstract 1580: Differential induction of reactive oxygen species by histone deacetylase inhibitors for mediating selective apoptosis of oncogenic H-Ras-expressing cells
Authors: Choudhary Shambhunath , Wang Hwa-Chain R.
Published: February 2011

This study is to understand the mechanisms involved in the reactive oxygen species (ROS)-mediated pro-apoptotic ability of H-Ras to enhance apoptosis induced by histone deacetylase inhibitors (HDACIs). Oncogenic induction of the ras genes is widely involved in human cancers. Expression of oncogenic H-Ras increases susceptibility of human and mouse cells to HDACIs, such as FK228 and trichostatin A, for inducing caspase activation and selective apoptosis. To understand the mechanisms for HDACI-induced differential activation of caspases and apoptosis in oncogenic H-Ras-expressing cells, we investigated the role and regulation of ROS in HDACI-induced cell death. We detected that expression of oncogenic H-Ras resulted in potentiating intracellular ROS machinery, increasing the susceptibility to HDACIs for enhancing the production of ROS, and depleting glutathione, leading to differential activation of caspases and cell death. Furthering our understanding of how oncogenic H-Ras augmented the generation of ROS, we detected that expression of oncogenic H-Ras was able to increase the level of Nox1, a homologue of the catalytic subunit of the superoxide-generating NADPH oxidase. Suppression of Nox1 by the specific inhibitor diphenylene iodonium or specific siRNAs significantly reduced ROS production induced by oncogenic H-Ras and HDACIs as well as HDACI-induced cell death of oncogenic H-Ras-expressing cells. Our results led us to a suggestion that increased ROS played a contributing role in the proapoptotic ability of oncogenic H-Ras to enhance HDACI-induced activation of caspases for inducing selective apoptosis in a dose-dependent manner; Nox1 played an important role in the ability of oncogenic H-Ras to potentiate ROS-producing machinery for enhancing cell susceptibility to HDACIs and, in turn, increasing ROS contents leading to caspase activation and selective apoptosis. Differential increases of intracellular ROS by oncogenic H-Ras to potentiate cell death should be seriously considered as a potential target in developing therapeutic strategies to control oncogenic H-Ras-involved human cancers by HDACIs.

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 1580.