bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5585: Optimal conditions for dendritic cells labeling with superparamagnetic iron oxide for cellular magnetic resonance imaging
Authors: Kobayashi Yasunobu , Shimizu Koichi , Okuyama Ryuji , Imai Kenichiro , Ohno Satoshi , Ostapenko Valentina V. , Kobayashi Tamiyo , Aruga Atushi , Tanigawa Keishi
Published: February 2011

Non-invasive cell-tracking in vivo could be an invaluable tool in cell-based therapy, which determines whether or not administrated cells effectively reach their target sites. Recent reports have shown that magnetic resonance imaging (MRI) is a useful and feasible tool to detect in vivo migration and biodistribution of magnetically labeled cells. In this study, we examined optimal conditions for labeling monocyte-derived dendritic cells (Mo-DCs) with a MR contrast agent (Resovist®) consisting of superparamagnetic iron oxide (SPIO) particles. We found that simple addition of Resovist® in the culture medium makes it possible to label Mo-DCs sufficiently and efficiently, and SPIO-uptake appeared to be saturated by its 100μg/ml treatment. FCM analysis showed that expression levels of CD80, CD86, CCR7, HLA-A,B,C and HLA-DR in SPIO-labeling Mo-DCs (100μg/ml Resovist®-treated) were similar to those in non-labeling cells. In vitro migration assays revealed that there were no significant differences between labeling and non-labeling cells in both chemotactic activities to CCL19 and random migration capacities on fibronectin-coated plates. In addition, IFNγ-ELISPOT assay showed labeling and non-labeling Mo-DCs were able to stimulate antigen-specific T cells to a similar extent, indicating that Resovist®-treatment did not affect the capacities of Mo-DCs to take up, process and present antigens to T cells. Taken together, we concluded that labeling of Mo-DCs with SPIO, particularly with 100μg/ml Resovist® could be a potent method for monitoring trafficking and biodistribution of these cells in clinical studies.

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 5585.
Abstract 5595: Antitumor immune responses to Nitroreductase/CB1954 and 4-1BBL gene therapy
Authors: Salman Asmaa M. , Searle Peter F.
Published: February 2011

Gene-directed enzyme prodrug therapy using the non-mammalian nitroreductase enzyme (NTR) and CB1954 prodrug is a promising approach for local management of cancer through targeted chemotherapy. Whilst there is some evidence that tumor cell killing via NTR/CB1954 may also induce a systemic, immune bystander effect, this needs further investigation. To address this, a transgenic adenocarcinoma of the mouse prostate tumor cell line stably expressing cytoplasmic ovalbumin (TRAMPOva) was transduced with retroviruses encoding either the therapeutic NTR or 4-1BBL gene. The generated sub-clones were used to establish subcutaneous tumor in syngeneic mice. Adoptive transfer of Ova-specific transgenic (OT-1) T cells facilitates tracking of the specific anti-tumor immune response to the gene therapy in vivo. By examining the effect of NTR/CB1954 mediated cytotoxicity on the generation of effector memory T cells, we find that treatment of Ova+NTR+ tumor bearing mice with prodrug induced significant tumor regression. This was associated with enhanced CD8+ T cell maturation and cytolytic activity. However, adoptive transfer of 1×105 of these Ova-specific memory cells did not provide prophylactic protection to immunodeficient mice against TRAMPOva tumor challenge. Therefore, we attempted to enhance the immunogenicity of tumors by delivering the 4-1BBL costimulatory ligand gene to tumor cells. We demonstrate that immunocompetent mice receiving TRAMPOva+4-1BBL cells resisted tumor formation in a 120 day follow-up period, while those receiving TRAMPOva cells developed progressive tumors at earlier time points. Tumor rejection was accompanied by generation of higher frequencies of Ova-specific CD8+ memory T cells that showed effector cytolytic function following challenge with splenocytes loaded with Ova peptide in vivo. Overall, our results show that either NTR/CB1954-mediated cell death, or tumor expression of 4-1BBL can induce a tumor-specific CD8+ T cell response. Combining these approaches may offer a strategy to provide long-lasting anti-tumor immunity in vivo.

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 5595.
Abstract 5596: Enhanced anti-tumor effect of combination therapy with anti-CD40 antibody and the mTOR kinase inhibitor AZD8055
Authors: Jiang Qun , Weiss Jonathan M. , Ortaldo John R. , Back Timothy , Guichard Sylvie , Thakurta Anjan , Wiltrout Robert H.
Published: February 2011

mTOR signaling, which plays a central role in controlling cell cell proliferation, survival, mobility and angiogenesis, is considered an important target for new anticancer drugs development. The involvement of the CD40/CD154 signaling pathway has also been reported to play an important role in regulating anti-tumor immune responses. In this study, using a first-in-class orally bioavailable mTOR kinase inhibitor, AZD8055, which, unlike rapamycin, can inhibit both mTORC1 and mTORC2, we evaluated the anti-tumor efficacy of mTOR kinase inhibitor treatment alone in a murine model of metastatic renal cell carcinoma (Renca) and compared biological responses achieved by administering AZD8055 as a single agent to those obtained in combination with agonistic anti-CD40 antibody. In vitro survival assays showed that Renca cell apoptosis could be induced by AZD8055. In vivo, although both agents administered alone had some anti-tumor efficacy, the combination of AZD8055 and CD40 Ab induced a significant anti-tumor response in both intra-renal and intra-splenic inoculations model of renal cell carcinoma, as compared to single agent treatments. The combination treatment, also resulted in an increase and activation of tumor- and liver-associated macrophages, NK cells and CD8 T cells in vivo. AZD8055/anti-CD40 treatment also increased the level of systemic Th1 cytokines, including IL-12, IFN-γ, TNFα. IFN-γ production by CD8+ T cells and TNFα production by macrophages were also found to be elevated in the AZD8055/anti-CD40 combination treated-group, compared with any single treatment group. Furthermore, the expression of Th1-associated chemokines, RANTES and IP10, were significantly induced in the combination treated-group. These data suggest that the combination of mTOR kinase targeting agents with immunotherapy could be an area of further development in renal cancer 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 5596.
Abstract 5649: Highly synergistic anti-tumor efficacy induced by the combination of two natural dietary agents, luteolin and EGCG: Role of p53 phosphorylation, stabilization and translocation
Authors: Amin A.R.M. Ruhul , Wang Dongsheng , Zhang Hongzheng , Peng Shifang , Koenig Lydia , Brandes Johann C. , Mourad Tighiouart , Khuri Fadlo R. , Chen Zhuo G. , Shin Dong M.
Published: February 2011

Natural dietary agents have drawn a great deal of attention for cancer prevention and therapy because of their wide safety margin and easy availability. However, single agent intervention has failed to bring the expected outcome in clinical trials in many instances; therefore, combinations of chemopreventive agents are gaining increasing attention. In the present study, we have investigated a combinatorial approach using two natural dietary polyphenols, luteolin and EGCG, and found that combination of the two compounds at low doses (at which almost no apoptosis was observed after single agent treatment) tremendously increased apoptosis (50-70%) in both head and neck and lung cancer cell lines (a panel of 11 cell lines tested). This combination also significantly inhibited growth of head and neck cancer Tu212 and lung cancer A549 xenografts as compared with either of the single agents (P value < 0.05). Ki-67 and TUNEL staining of the xenografted tumor tissues also showed statistically significant decrease in the number of Ki-67 and increase in TUNEL positive cells after combined treatment with luteolin and EGCG as compared with single agent treatment or untreated control. Further mechanistic study showed that the combination-induced both mitochondria-dependent and -independent apoptosis varying among cell lines. Although the combination was effective against cell lines regardless of their p53 status, those with wild-type p53 were much more sensitive to the treatment than those with mutant or no p53. Ablation of p53 using shRNA strongly inhibited apoptosis (>50%) as evidenced by decreased PARP and caspase 3 cleavage. Moreover, we found more efficient stabilization and phosphorylation of p53 at Ser15 by the combination as compared with either single agent, particularly when the basal p53 levels were low. In addition, we observed mitochondrial translocation of p53 after treatment with luteolin or the combination of EGCG and luteolin. Taken together, our results, for the first time, suggest that combination of luteolin and EGCG has synergistic/additive growth inhibitory effects both in vitro and in vivo via a p53-dependent pathway and will provide an important rationale for chemoprevention or treatment trials using this combination. This research was supported by the National Cancer Institute award 5 P50 CA128613 SPORE in Head and Neck Cancer (ARA, JCB, TM, FRK, ZGC and DMS).

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 5649.
Abstract 5653: The in vitro effects of aloe-emodin on head and neck squamous cell carcinoma
Authors: Chaisuparat Risa , Scheper Mark A. , Thunyakitpisal Pasutha
Published: February 2011

Aloe emodin (AE) is an anthraquinone compound extracted from the leaves of aloe vera plants, which has been shown to have anti-neoplastic activities on various cancers. This study investigated the effects of AE on cell proliferation and apoptosis induction in head and neck squamous cell carcinoma (HNSCC) using a HEP-2 cell line model. HEP-2 cells were either left untreated, normal media, (Control) or treated with different concentrations of AE (6.25-100 µM) for 24 h. Cell proliferation was evaluated using MTS and crystal violet staining assays. Cell cycle was analysed using flow cytometry measuring DNA content (Propidum Iodide). Apoptosis was analysed by TUNEL and apoptotic gene expression was measured by human apoptosis RT2 Profilertm polymerase chain reaction array. Cell proliferation assays showed that AE inhibited cell proliferation in a dose dependent manner. MTS assay demonstrated a 26.96% and 43.12% decrease in cell proliferation at 6.25 and 12.5 µM, respectively. In confirmation of the MTS assay, crystal violet staining displayed 35.58% and 39.42% reduction in cell proliferation at 6.25 and 12.5 µM, respectively. Further, AE treatment demonstrated an increase in G1 cell cycle arrest compared to the control. Apoptosis analysis exhibited an increase in early and late stage apoptotic cells in the AE treated group. TUNEL assay demonstrated a 2 to 3 fold increase in apoptosis compared to the control. Finally, the apoptotic gene expression array revealed differential expression among the 12.5 µM AE treated cells and control cells of several genes involved in apoptosis including: TNF, BCL2, caspase and death domain gene families. In conclusion, we present original data for the first time showing AE is capable of producing anti-neoplastic effects, inhibiting cell proliferation and inducing apoptosis, in HNSCC.

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 5653.
Abstract 5672: A novel anti-cancer effect of hesperidin: reversion of epithelial mesenchymal transition in human prostate cancer cells
Authors: Lau Yiu-Keung
Published: February 2011

Prostate cancer is the most common noncutaneous malignancy in men. About one third of prostate cancers invade surrounding tissues, and metastasize to distant organs at the time of diagnosis. Once prostate cancer metastasizes to distant organs, the disease is basically not curable. The median survival for men with metastatic prostate cancer is 1 to 3 years. Epithelial mesenchymal transition (EMT) is a process facilitating cancer cell invasion and metastasis. Hesperidin (3′-5,7-trihydroxy-4′-methoxyflavanone 7-rhamnoglucoside) is a flavonoid found abundantly in citrus fruits. It demonstrates anti-inflammatory, anti-oxidative, and anti-proliferative actions in various cancer types. Its effect on EMT of prostate cancer is not known. We therefore hypothesize that hesperidin inhibits the cell growth and EMT of prostate cancer cells. In our study, we use androgen-sensitive prostate cancer LNCaP cells, androgen-insensitive Du 145 and PC3 cells, and benign prostate BPH-1 cells. These cell lines are treated with increasing concentrations of hesperidin, from 10 µM to 200 µM. We first examine the effects of hesperidin on cell viability by MTT assays. Hesperidin inhibits all three prostate cancer cell viability in a dose dependent manner but it has no significant effects on that of normal prostate cells, BPH-1. We then examine whether hesperidin reverses EMT in these cells by investigating the migration ability and the expression of EMT marker. Hesperidin at 100 µM and 200 µM inhibits the cell migration ability of PC3 and LNCaP as showed by wound scratch assay. Next, we examine expression of E-cadherin, a molecular marker for EMT, by immunohistochemistry. Hesperidin at 100 µM significantly enhances the membranous expression of E-cadherin in LNCaP cells after 48 hours of treatment as compared to the control. There are no significant changes in androgen receptor (AR) protein level or PSA mRNA after hesperidin treatment suggestive that the effects of hesperidin on LNCaP cells are AR-independent. In conclusions, our data provide novel findings that hesperidin can induce the reversion of EMT in prostate cancer cells. Hesperidin may therefore be a potential chemopreventive agent in human prostate 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 5672.
Abstract 569: Dicycloplatin, a platinum compound appears effective in treating prostate cancer
Authors: Yang Xuqing , Guo Yi , Mueller Michael D. , Yu Jing Jie
Published: February 2011

Dicycloplatin (DCP) is a new platinum-based drug developed in China. Due to its special structure, DCP possesses superior stability and water-solubility, compared to cisplatin and carboplatin. Experimental findings in China demonstrate low in vitro cytotoxicity of dicycloplatin against a variety of human cancer cell lines. DCP toxicity profile of 210 mg/kg of LD50 compares favorably to 14.27 mg/kg for cisplatin and 164 mg/kg for carboplatin. In vivo studies indicate that IV administration of 20 mg/kg DCP in rats is followed by 3.64 μg/g of drug distribution in the prostate. Histoculture Drug Response Assay (HDRA) confirms clinical efficacy of chemotherapy for various cancer types, including prostate cancer. Pre-clinical and clinical studies in China suggest that DCP produces fewer side effects with a maximum tolerated dose of 650 mg/m2. Patients with prostate cancer treated by DCP alone demonstrated persistent benefits. In one case, the prostate-specific antigen (PSA) level returned to normal after 5 consecutive dosages of 600mg administered orally every two weeks. No significant side effects were observed. Investigations of molecular mechanisms at WVU, USA suggest that DCP induces gene signature profile in human ovarian cancer cells through mechanisms similar to other platinum drugs. In conclusion, dicycloplatin may be an effective chemotherapeutic agent for patients with prostate cancer and further investigations in animal and preclinical tests are warranted.

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 569.
Abstract 5703: Up-regulation of miR-146a contributes to the inhibition of invasion of pancreatic cancer cells
Authors: Li Yiwei , VandenBoom Timothy , Wang Zhiwei , Kong Dejuan , Ali Shadan , Philip Philip A. , Sarkar Fazlul H.
Published: February 2011

Pancreatic cancer (PC) is an aggressive malignancy with high mortality primarily due to its highly invasive and metastatic behavior. Over-expression of EGFR and activation of NF-κB are frequently observed in PC associated with high metastatic capacity. Emerging evidence also suggest the critical role of microRNAs (miRNAs) in the regulation of various biological and pathological processes including metastasis. Moreover, miR-146a has been found to be lost in metastatic prostate cancer and its expression reduces the metastatic potential of breast cancer cells through repression of IRAK1 (interleukin 1 receptor-associated kinase 1) and subsequent inhibition of NF-κB activity. In the present study, we assessed the expression pattern of miRNAs in the normal pancreatic duct epithelial cells and pancreatic cancer cells. We also investigated whether the treatment of PC cells with either B-DIM (BioResponse formulated 3,3′-diinodolylmethane with greater bioavailability) or G2535 (a mixture of genistein and other isoflavones) could alter the expression of miRNAs and their targets that are involved in the processes of invasion and metastasis. We found lower expression of miR-146a in PC cells compared to normal pancreatic duct epithelial cells. Interestingly, re-expression of miR-146a inhibited the invasive capacity of Colo357 and Panc-1 PC cells with concomitant down-regulation of EGFR and IRAK-1. Mechanistic studies including miR-146a re-expression, anti-miR-146 transfection, and EGFR knock-down experiment showed that there was a crosstalk between EGFR, MTA-2, IRAK-1, IκBα, and NF-κB. Most importantly, we found that the treatment of PC cells with B-DIM or G2535 could increase the expression of miR-146a and consequently down-regulated the expression of EGFR, MTA-2, IRAK-1, and NF-κB, resulting in the inhibition of invasion of Colo357 and Panc-1 cells. These results provide experimental evidence in support of the role of DIM and isoflavone as a potential non-toxic agent as regulators of miRNA, which could be useful for the inhibition of cancer cell invasion and metastasis, suggesting that these agents could be important for designing novel targeted strategy for the treatment of PC.

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 5703.
Abstract 5719: Epigallocatechin-3-gallate, a green tea polyphenol, reactivates silenced tumor suppressor gene by modifying DNA methylation and histones in human skin cancer cells
Authors: Vaid Mudit , Nandakumar Vijayalakshmi , Katiyar Santosh K.
Published: February 2011

Epigenetics, the heritable processes that modulate gene activity without changes in the DNA sequence, have gained considerable interest in cancer development and molecular targets of cancer treatment. Cancer epigenetics deal with important processes like DNA methylation and histone modification patterns that can either activate oncogenes or inactivate tumor suppressor genes, the crucial steps in tumor development. Accumulating data suggest that dietary factors may alter cancer risk by modifications of epigenetic processes in the cancer cell. Therefore, the present study was designed to investigate whether (−)-epigallocatechin-3-gallate (EGCG), a most potent polyphenol from green tea which has anti-carcinogenic activity, would alter epigenetic events to regulate methylation-silenced tumor suppressor genes in human skin cancer cells. DNA methylation, histone modification and gene expression profile were studied using human epidermoid carcinoma A431 cells and melanoma cells as an in vitro model after EGCG treatment using RT-PCR, western blot analysis, cytostaining, southwestern dot-blot analysis, chromatin immunoprecipitation, enzymatic activity assays and fluorescence activated cell sorting (FACS) analysis of apoptotic cell death. Our study shows that treatment of A431 cells for 3 or 6 days with EGCG at lower concentrations (5, 10 and 20 μg/ml) resulted in DNA demethylation and reduction in the mRNA and protein levels of DNA methyltransferases (DNMTs) 1 and 3a and 3b and the activity of DNMTs in A431 cells in a dose- and time-dependent manner. EGCG also increased the levels of acetylated lysine 9 and lysine 14 on histone H3 (H3-Lys 9, H3-Lys 14), but decreased levels of methylated H3-Lys 9. Under identical conditions, EGCG re-expressed mRNA and protein levels of tumor suppressor genes, p16INK4a and p21WAF1/CIP1, in A431 cells in a dose-dependent manner. Re-expression of p16INK4a and p21 by EGCG treatment of the A431 cells leads to the inhibition of cell proliferation and induction of apoptosis of A431 cells. Together, our study demonstrates that EGCG can epigenetically modulate DNA and histones to activate methylation-silenced tumor suppressor genes. These epigenetic modifications by EGCG may contribute to skin cancer prevention/treatment strategies in humans.

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 5719.
Abstract 5755: Molecular mechanisms of small cell lung carcinoma development using preclinical mouse models
Authors: Park Kwon-Sik , Sage Julien
Published: February 2011

Small cell lung carcinoma (SCLC) is a neuroendocrine subtype of lung cancer with a 5-year survival rate of less than 10%. A mouse model for human SCLC has been developed based on the fact that the RB and p53 tumor suppressor genes are mutated in more than 90% of human SCLC tumors. Rb/p53 mutant mouse lung tumors closely resemble human SCLC at the cellular and molecular levels, providing a model to probe the mechanisms underlying the development and the maintenance of SCLC in vivo.

Based on preliminary evidence in a small number of human samples and tumor cell lines, we have examined the possibility that SCLC tumors may rely on the Hedgehog (Hh) signaling pathway for their growth. Hh signaling plays a key role during normal lung development and response to injury but normally has low activity in the lung epithelium. In contrast, when we crossed Rb/p53 mutant mice to Ptch1lacZ/+ reporter mice, we found that Hh signaling was active in all the SCLCs that developed. Experiments with cell lines derived from mouse tumors also indicated that the activation of Hh signaling in these cells was cell-autonomous. Constitutive activation of the Hh pathway using a mutant allele of Smo was sufficient to enhance SCLC development in vivo. Inhibition of the Hh pathway with Cyclopamine and GANT61 reduced the survival of SCLC cells in culture and of primary tumors in vivo, indicating that activation of the Hh pathway is also necessary for the expansion of these tumor cells. Thus, the Hh pathway is active in SCLC cells and plays an intrinsic role in the initiation and the maintenance of SCLC. These observations in a pre-clinical model suggest that inhibition of this signaling pathway may provide a novel means to treat SCLC patients.

Emerging evidence in patients and mouse models also suggests that p130, a gene related to RB, may act as a tumor suppressor in SCLC cells. To test this idea, we used conditional mutant mice to delete p130 in combination with Rb and p53 in adult lung epithelial cells. We found that loss of p130 resulted in increased proliferation and significant acceleration of SCLC development, indicating that p130 plays a key tumor suppressor role in SCLC and providing an improved mouse model for SCLC. We are currently using this triple knock-out mouse model to identify the cell(s) of origin for SCLC as well as to elucidate the mechanisms behind the high metastatic potential of this tumor type.

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 5755.
Abstract 5765: Tumor-elicited myeloid progenitors promote metastasis through induction of mesenchymal to epithelial transition
Authors: Gao Dingcheng , Joshi Natasha , Choi Hyejin , Ryu Seongho , Hann Mary , Mittal Vivek
Published: February 2011

Malignant primary tumor cells colonize in target organs to form dormant micrometastasis. In some cases, the micrometastases progress to macrometastasis resulting in more than 90% of human cancer related deaths. However, the cellular and molecular regulators of metastatic initiation and progression remains poorly understood. Using a variety of metastatic tumor models we show that recruited bone marrow-derived myeloid progenitor cells comprise a significant fraction of the metastatic lung as compared to the primary tumor that predominantly have infiltrated macrophages. Specific depletion of the myeloid progenitor cells did not affect primary tumor growth but significantly impaired lung metastases. Global gene expression profiling of the CD11b+GR1+ myeloid progenitor cells identified potential pro-metastatic mediators. We have characterized one such mediator that promotes lung metastasis via promoting mesenchymal to epithelial transition (MET) of disseminated tumor cells. Our data suggests that this transition favors enhanced proliferation and survival of disseminated tumor cells so that they can successfully form functional metastases. RNAi-mediated acute suppression of this mediator in the bone marrow markedly inhibited lung metastases. Taken together, these findings illustrate the critical roles of the myeloid progenitors in metastasis and suggest the potential impact of targeting bone marrow cells and MET pathways in metastatic disease.

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 5765.
Abstract 577: Combination therapy with arsenic trioxide and radiation in oral squamous carcinoma
Authors: Zhang Xinyan
Published: February 2011

Objective: As a cancer therapeutic drug, arsenic trioxide (As2O3) was originally developed for promyelocytic leukemia. The emerging importance As2O3 in other solid tumors prompted extensive studies of mechanism of action of As2O3 in other types of cancer. Radiation is a commonly used therapeutic treatment for oral squamous carcinoma, while high dose radiation treatment is invasive with unwanted side effects. The aim of this study was to investigate if combined treatments with As2O3 and low dose radiotherapy could enhance the anti-tumor effects. Materials and Methods: Human oral squamous cell lines KB and Tca8113 and Human umbilical vein endothelial cells (HUVEC) were irradiated in vitro with a dose of 7.5Gy with or without low to high doses of As2O3. Cell survival was assessed by MTT assay. Flow cytometry was performed for the analysis of apoptosis. Tumor cell colony formation assay was detected in KB and Tca8113 cells and endothelial tube formation assay was evaluated in HUVEC. Nude mice xenografted animal model with oral cancer cells was established to evaluate the combination treatment efficacy of As2O3 and radiation. Results: As2O3 was able to enhanced radiation-induced tumor cell apoptosis and enhance radiation-induced inhibition of tumor cell proliferation and colony formation and endothelial cell tube formation. In vivo study, the combination treatment efficacy of As2O3 and radiation attained a significant decrease in the incidence of tumor development and tumor volume in nude mice. Conclusions: All these results suggested that As2O3 could enhance the therapeutic efficacy of low dose radiation treatment in vitro and in vivo in oral squamous carcinomas.

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 577.
Abstract 5771: Molecular radiation therapy: Targeting DNA damage response proteins
Authors: Bart Cornelissen , Kersemans Veerle , Darbar Sonali , Smart Sean , Vallis Katherine A.
Published: February 2011

DNA damage is an early event after exposure of cells to many anti-cancer agents. Auger electron-emitting radiopharmaceuticals that localize at sites of DNA-double strand breaks (dsb) cause added damage, thus stimulating the formation of their own target and converting sublethal DNA lesions into irreparable damage. The histone H2A variant, H2AX, is phosphorylated on Ser139 (γH2AX) and forms foci at DNA-dsb. γH2AX foci are generally more numerous and resolve more slowly in cancer cells which are genomically unstable compared to normal cells. The aim of this study was to target γH2AX foci for molecular radiation therapy.

Methods: Anti-γH2AX (aγH2AX) or anti-mouse IgG (amIgG) monoclonal antibodies were modified by addition of a nuclear localizing signal (NLS)-containing cell penetrating peptide, TAT, through N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide/N-hydroxysuccinimide (EDC/NHS) coupling. Cyclic diethylenetriaminepentaacetic dianhydride (cDTPA) was added for radiolabeling with 111-indium. Fluorophore AlexaFluor 488-labelled variants of both radioimmunoconjugates (RICs) were also prepared.

Results: Using confocal microscopy, AF488-aγH2AX-TAT but not AF488-amIgG-TAT was found to colocalize with γH2AX-foci in cells exposed to X-Ray irradiation (IR) (4 Gy). To evaluate cellular retention of RICs, MDA-MB-468 or MDA-MB-231/H2N human breast cancer cells were treated with 111In-aγH2AX-TAT or 111In-amIgG-TAT (0.5 µg, 0.1 MBq/µg) and exposed to IR (4 Gy) or bleomycin (20 µg/mL). 111In was retained 16-fold longer in IR- or bleomycin-treated cells exposed to 111In-aγH2AX-TAT compared to control cells exposed to 111In-aγH2AX-TAT. 111In-aγH2AX-TAT (6 MBq/µg) caused amplification of both IR-induced DNA-dsb (evaluated by γH2AX foci number and the neutral comet assay [NCA]) and clustered DNA damage (evaluated by NCA plus glycosylases). In clonogenic assays, the combination of 111In-aγH2AX-TAT plus IR or bleomycin was significantly more cytotoxic than either agent alone and more cytotoxic than 111In-amIgG-Tat plus IR or bleomycin alone. In in vivo experiments, uptake of 111In-aγH2AX-TAT, but not 111In-amIgG-TAT, was up to 6-fold greater in MDA-MB-231/H2N xenografts exposed to IR (4 or 10 Gy) and in bleomycin-treated mice compared to untreated controls. The volume doubling time of MDA-MB-231/H2N xenografts increased 13-fold (p < 0.05) in animals treated with IR (10 Gy) plus 111In-aγH2AX-TAT (10 µg, 6 MBq/µg) compared to those exposed to IR or 111In-αγH2AX-TAT alone.

Conclusion: 111In-aγH2AX-TAT is a novel radiopharmaceutical that amplifies DNA-damage and enhances the cytotoxicity of IR and chemotherapy in vitro and in vivo.

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 5771.
Abstract 591: Host cell DNA damage and inflammation responses determine oncolytic adenovirus efficacy in ovarian cancer
Authors: Salako Michael A. , Connell Claire M. , Shibata Atsushi , Graupner Vilma , Lockley Michelle , Balkwill Frances R. , McNeish Iain A.
Published: February 2011

Introduction. Oncolytic adenoviruses show promise as a cancer treatment, by replicating selectively within malignant cells. Viral replication requires multiple cell cycle checkpoints to be overcome. Ovarian cancer sensitivity to viral cytotoxicity varies greatly, even between cells with similar infectivity and intracellular virion production. Viruses also generate acute inflammatory responses with production of cytokines, especially TNF-α. We investigated the role of cellular DNA damage in efficacy of adenovirus dl922-947 in ovarian cancer and also whether inhibition of TNF-α augments activity.

Methods. Host DNA damage and repair pathways were assessed in ovarian cancer lines, TOV21G, IGROV1 and A2780CP, which cover three-log range of virus sensitivity. The ATR-chk1 pathway was inhibited using siRNA and UCN-01 treatment. In addition, inflammatory cytokine responses to dl922-947 were assessed in vitro and in xenograft models. TNF-α was inhibited using shRNA and monoclonal antibodies.

Results. Oncolytic adenovirus cytotoxicity is associated with extensive genomic DNA damage. Following infection, sensitive, but not resistant, ovarian cancer cells activate cdc25a and over-replicate genomic DNA, creating extensive double-strand breaks. Inhibition of ATR-chk1 in resistant cells augments cdc25a activity and increases genomic DNA over-replication. This enhances cytotoxicity without increasing E1A expression or viral replication. In addition, dl922-947 induces transcription of TNF-α, IL-6 and IL-8 in ovarian cancer cells and xenograft-bearing mice prior to any viral gene expression and host NF-κB activation. Both RNAi-mediated TNF-α knockdown and anti-TNF-α monoclonal antibody treatment increase virus cytotoxicity in vitro and in IGROV1 intraperitoneal xenografts. The increased efficacy results from suppression of cIAP1 transcription in malignant cells and a consequent increase in caspase-mediated apoptosis.

Conclusions. A phase I trial of dl922-947 in women with relapsed ovarian cancer is planned for 2011. Host cell DNA damage is a key determinant of oncolytic adenoviral activity, whilst TNF-α acts as a survival factor in infected cells. Inhibiting both repair of DNA damage and TNF-α could improve anti-tumour activity in future clinical trials.

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 591.
Abstract 595: Single adenovirus-mediated simultaneous expression of p53 and the artificial microRNAs targeting anti-apoptotic p53 target genes
Authors: Idogawa Masashi , Sasaki Yasushi , Imai Kohzoh , Shinomura Yasuhisa , Tokino Takashi
Published: February 2011

Gene transfer involving p53 is viewed as a potentially effective cancer therapy, but does not result in a good therapeutic response in all human cancers. Several p53 target genes have an inhibitory effect on p53-mediated apoptosis. Therefore, if the induction of these genes by p53 is selectively suppressed, the therapeutic effectiveness would be improved. In previous study, we constructed a replication-deficient recombinant adenovirus that encoded co-cistronic p53 and artificial microRNAs (miRNAs) targeting p21, a representative p53 target gene which have an anti-apoptotic effect, resulting in p53 expression and the suppression of p21 induction simultaneously. In colorectal and hepatocellular carcinoma cells, infection with the adenovirus vector augmented apoptosis and suppressed tumor growth as compared to an adenovirus that expressed p53 alone in vitro and in vivo. In this study, we additionally inserted miRNA sequences targeting other anti-apoptotic genes such as MDM2 to the vector and evaluated the therapeutic effectiveness of p53 expression in combination with the suppression of several anti-apoptotic p53 target genes. Infection with the vector suppressed the induction of anti-apoptotic target genes and induced apoptosis more efficiently in cancer cells. These results suggest that adenovirus-mediated transduction of p53 and miRNAs targeting anti-apoptotic p53 target genes is useful for therapy of human 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 595.
Abstract 628: A novel SND1-BRAF fusion confers resistance to the cMet inhibitor PF-04217903 in GTL16 cells
Authors: Lee Nathan V. , Ching Keith , Lira Maruja , Pavlicek Adam , Dillon Roslyn , Srinivasa Sreesha P. , Nilsson Carol , Greig Michael , North Michael , Rejto Paul , Christensen James G.
Published: February 2011

The hepatocyte growth factor receptor (HGFR/cMET) signaling pathway is a driver of tumorigenesis in a variety of tumor types, and a number of agents targeting cMet, including PF-04217903, are under investigation in clinical trials. Tumor types exhibiting an amplified MET gene locus such as gastric, NSCLC, or esophageal cancers are of particular interest for clinical development of c-Met inhibitors. While inhibition of other receptor tyrosine kinases (RTKs) such as ErbB2, EGFR, or KIT have proven to be effective treatments for cancer patients, most tumors become refractory to respective targeted therapies due to the emergence of resistance mechanisms associated with drug targets or upregulation of compensatory pathways. To identify potential mechanisms of resistance to c-Met inhibitors, a gastric carcinoma line (GTL16) was placed under selective pressure by culturing cells in increasing concentrations of PF-0421703 in vitro and resistant clones were isolated. Resistant clones were characterized for changes in signaling, gene expression, and DNA copy number variation as compared to parental GTL16 cells. These studies resulted in the identification of genomic rearrangements at the 7q32 and 7q34 loci which produce a novel SND1-BRAF fusion protein in resistant cells. The fusion protein includes the BRAF kinase domain and is both constitutively active and overexpressed relative to parent cells as determined by gene expression array, immunoblot, and mass spectrometry. In addition, phosphoproteomic analyses demonstrated enrichment of phosphopeptides associated with the MAPK pathway signaling proteins relative to wildtype cells. Cells expressing the fusion protein exhibited resistance to multiple c-Met inhibitors whereas treatment of resistant cells with a combination of c-Met and BRAF inhibitors or a MEK inhibitor (PD325901) reversed the resistance phenotype by reestablishing inhibition of MAPK signaling and restoring growth inhibition. Together, these data provide an unique example of a mechanism where MAPK activation, through BRAF amplification/rearrangement, confers resistance to a RTK/cMET inhibitor. Furthermore, the results suggest the importance of MEK/ERK signaling downstream of c-Met and that a potential combination strategy for c-Met inhibitors with BRAF or MEK inhibitors could be employed to delay onset or circumvent potential resistance mechanisms.

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 628.
Abstract 63: TKTL1 is activated by promoter hypomethylation and contributes to head and neck squamous cell carcinoma carcinogenesis via increased aerobic glycolysis and HIF1-alpha stabilization
Authors: Sun Wenyue , Liu Yan , Glazer Chad A. , Shao Chunbo , Bhan Sheetal , Demokan Semra , Zhao Ming , Rudek Michelle A. , Ha Patrick K. , Califano Joseph A.
Published: February 2011

Described decades ago, the “Warburg effect”, an elevation in aerobic glycolysis, is a fundamental property of cancer cells. Lactate and pyruvate, the end products of glycolysis, are highly produced by cancer cells even in the presence of oxygen. Previously, we observed promoter hypomethylation and overexpression of TKTL1 (Transkelolase-like 1) in Head and Neck Squamous Cell Carcinoma (HNSCC). This study aimed to investigate whether aberrant expression of TKTL1 contributes to HNSCC tumorigenesis and whether this is associated with aerobic glycolytic metabolism. We found that TKTL1 exhibits high frequency of promoter hypomethylation in HNSCC tumors compared with the normal oral epithelial mucosa, correlating with its overexpression in HNSCC. Overexpression of TKTL1 in HNSCC cells promoted cellular proliferation and enhanced tumor growth in vitro and in vivo. Further, in a murine xoenograft and human model of HNSCC, we found that overexpression of TKTL1 increased the production of fructose-6-phosphate and glyceraldehyde-3-phosphate, in turn elevating the production of pyruvate and lactate production accompanied by the elevated glucose uptake and ATP production. Importantly, overexpression of TKTL1 is associated with the normoxic stabilization of the malignancy-promoting transcription factor HIF1α by aerobic glycolytic metabolites including pyruvate and lactate. Notably, reduction of TKTL1 expression decreased HIF1α accumulation, and inhibition of HIF1α could abrogate the growth effects mediated by TKTL1 overexpression. These findings suggest that TKTL1 is a novel protooncogene that is epigenetically activated by aberrant hypomethylation and contributes to a malignant phenotype via altered glycolytic metabolism and HIF1α accumulation, providing opportunities for therapeutic targeting of metabolic pathways in 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 63.
Abstract 633: Tumor cell resistance mechanisms to aurora kinase inhibitors
Authors: Kollareddy Madhusudhan , Zheleva Daniella , Dzubak Petr , Hajduch Marian
Published: February 2011

Aurora kinase inhibitors are being developed as anti-cancer drugs and more than 10 small molecules are currently undergoing clinical trials. CYC116, an Aurora kinase inhibitor, discovered and developed by Cyclacel Ltd. is currently in phase I clinical trial in patients with advanced solid tumors. CYC116 showed significant anti-proliferative activity in preclinical studies. However tumor cell resistance mechanisms towards this Aurora kinase inhibitor have not been yet established. We developed several HCT116 p53 wild-type and HCT116 p53 null resistant clones towards CYC116 by exposing the cells to high drug concentrations. In order to compare resistance mechanisms, another Aurora kinase inhibitor, ZM447439, was used as a reference compound. Here we present the preliminary data characterizing CYC116-resistant clones. In MTT cytotoxicity assays all the clones showed CYC116 resistance and cross resistance to other Aurora kinase inhibitors, and to some anticancer drugs, which suggest a multidrug resistance phenotype. However the degree of resistance is variable between the clones. All CYC116-resistant clones irrespective of their p53 background became tetraploid. This was not observed for the ZM447439-resistant clones. PH3 (ser10), an Aurora kinase B phosphorylation site, was not inhibited in all resistant clones, suggesting that this kinase is still active. DNA and RNA synthesis were also not inhibited in these clones. Flow cytometry based studies revealed no up regulation of PgP drug transporter in all CYC116-resistant clones, whereas two HCT116 p53 null ZM447439-resistant clones displayed an increase in PgP levels. Up regulation of MRP was only detected in one HCT116 p53 null CYC116-resistant clone, which expressed high levels of this drug transporter. From the initial data it is obvious that there were no common resistance mechanisms towards the studied Aurora kinase inhibitors. We are continuing the characterization of these resistant clones, which include microarray gene expression studies, 2-D electrophoresis and mass spectrometry studies, Aurora A and B sequencing (target mutations), and other drug transporter (e.g. BCRP & LRP) expression studies. These will further help the understanding of the molecular basis of acquired tumor resistance to CYC116 and will aid us in predicting the clinical response as well as in designing combination treatment regimens for overcoming resistance hence furthering clinical development. This work was kindly supported by the Czech ministry of education. Grant number: MSM6198959216 and LC07017.

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 633.
Abstract 649: Dynamic magnetic resonance imaging of the effects of vascular targeting agents on intracerebral metastases
Authors: Muldoon Leslie L. , Gahramanov Seymur , Marshall Deborah J. , Neuwelt Edward A.
Published: February 2011

Objective: Agents that target tumor vasculature are gaining use as therapeutics for brain tumors. We used dynamic magnetic resonance imaging (MRI) to evaluate the vascular effects of the monoclonal antibodies bevacizumab, targeting vascular endothelial growth factor (VEGF), and intetumumab (CNTO 95), targeting αV integrins, in a rat model of lung cancer brain metastasis.

Methods: Female nude rats received intracerebral implantation of human LX-1 small cell lung carcinoma cells. At 10 days after tumor implantation, rats were untreated or treated with intetumumab (30 mg/kg IV) or bevacizumab (45 mg/kg IV) (n = 4-5 per group). MRI at 12T was performed prior to treatment and at 1, 3, and 7 days after treatment, using dynamic contrast enhanced (DCE) MRI with gadolinium-based contrast agent (GBCA), and dynamic susceptibility contrast (DSC) MRI with the blood pool iron oxide nanoparticle ferumoxytol. Tumor relative cerebral blood volume (rCBV) and permeability markers were assessed.

Results: Intetumumab increased brain tumor vascular permeability at 3 and 7 days after treatment on DCE-MRI, as determined by the ratio of maximum GBCA signal intensity to normal brain, a measure of the interstitial space volume fraction (ve), and time to peak enhancement, a surrogate for Ktrans, the rate constant for passive leakage across the blood-brain barrier. Intetumumab also increased tumor rCBV on DSC-MRI as compared to untreated controls. Tumors uniformly grew during the week assessment period. In contrast, bevacizumab decreased tumor permeability and rCBV, and slowed the increase in the volume of enhancing tumor on both T1-weighted and T2-weighted images, compared with controls.

Conclusions: The vascular targeting agents intetumumab and bevacizumab had diametrically opposite effects on dynamic MRI of tumor vasculature in a rat brain metastasis model. The αV integrin inhibitory antibody intetumumab appeared to increase tumor vascular permeability and blood volume, suggesting it may enhance chemotherapy efficacy by improving chemotherapy delivery to intracerebral tumors. Conversely, the effects of bevacizumab on tumor vasculature suggest it would actually decrease chemotherapy delivery, thereby minimizing chemotherapy efficacy.

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 649.