bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract LB-304: Bone marrow-derived endothelial cells migrate to tumor sites and contribute to functional tumor vasculature
Authors: Fontes Aparecida M. , Bonfim-Silva Ricardo , Souza Lucas Eduardo Botelho , Melo Fernanda Ursoli Ferreira , Oliveira Viviane Cassia , Magalhaes Danielle Aparecida Rosa , Cardoso Angelo A. , Rahal Paula , Covas Dimas Tadeu
Published: August 2014

Tumor expansion is dependent on neovascularization, a process that requires sustained new vessel formation. Although the critical role of angiogenesis by endothelial sprouting in this process, controversy still prevails on the whether vasculogenesis, involving bone marrow (BM)-derived endothelial cells, does contribute to this process. The objective of this study was to investigate the contributions of BM-derived endothelial cells to tumor vasculature, in a melanoma model using chimeric GFP mice. Methodology: First, wild-type C57BL/6 mice were was exposed to a single dose of 10 Gy X-irradition and rescued by transplantation of BM cells from C57BL/6-GFP mice. At d30 post-transplant, the animals received a subcutaneous infusion of melanoma cells stably transfected with the luciferase gene (B16/F10-Luc+). After 20 days, the tumors were harvested, and tumor stroma characterized using flow cytometry, bioluminescence-based image processing and confocal microscopy, to define the specific contribution of BM-derived cells. Results: Mice transplanted with donor GFP+ cells showed significant BM chimerism (90.9 ± 0.87%) demonstrating successful engraftment of donor BM stem/progenitor cells. Analyses of tumor specimens showed the presence of donor cells in the tumor sites (3.5±1.7%) in all animals, showing that BM-derived cells were effectively recruited to the developing melanoma. Interestingly, these cells represent endothelial cells (CD31+ cells; mean=X%) and myeloid-lineage cells (CD11b+ cells; mean=80%), but also tumor-infiltrating lymphocytes (CD8+ T cells, mean = 13.31; CD4+ T-cells, mean=2.1). Examination of the tumor endothelium by confocal microscopy clearly showed the presence of donor CD31/GFP cells in the vessel wall, namely in vessels lacking other mural components (as pericytes). Conclusions: Taken together, this study demonstrates that BM-derived cells are actively recruited to tumor sites, contributing to the tumor stroma and the formation of blood vessels in the developing tumor. We are performing studies to elucidate the molecular mechanisms involved in mobilization of of BM-derived precursor cells to the tumor microenvironment, and whether disruption of this vasculogeneic process significant impairs tumor development.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-304. doi:10.1158/1538-7445.AM2011-LB-304
Abstract LB-352: Functional significance of Zic1 and hsa-miR-23a over-expression in malignant mesothelioma
Authors: Cheng Yuen Yee , Jin Hong Chuan , Kirschner Michaela , van Zandwijk Nico , Reid Glen
Published: August 2014

Background: Epigenetic inactivation of tumour suppressor genes plays a crucial role in the progression of malignant mesothelioma (MM). Previous research has shown epigenetic gene silencing, through DNA methylation or through control of mRNA expression by microRNAs, to be important in MM. Our previous work indicated that Zic1 silencing in MM lines is only partially explained through DNA hypermethylation. Interestingly, miRNA microarray analysis revealed that hsa-miR-23a is over-expressed in MM cell lines, and that this miRNA has target sites in the 3′UTR of the Zic1 mRNA. The aim of the current study was to investigate the functional significance of Zic1 silencing and hsa-miR-23a over-expression in MM. Methods: We first confirmed DNA hypermethylation of Zic1 in human MM specimens using MSP, MS-HRM and COBRA. The expression level of hsa-miR-23a was also confirmed in MM using qPCR. To investigate the functional significance of Zic1 silencing, Zic1 was re-expressed in MM cell lines and effects on proliferation, migration and growth in soft agar were assessed. The relationship between hsa-miR-23a and Zic1 expression was investigated by the use of an antagonist of hsa-miR-23a. Results: Our results indicated that Zic1 is hypermethylated and ectopic expression of Zic1 inhibited cell migration and cell proliferation in MM cell lines. Hsa-miR-23a overexpression in MM is closely linked to the expression of Zic1. Our results suggest that Zic1 is a functional tumour suppressor gene that is silenced by a combination of hypermethylation and hsa-miR-23a-mediated inhibition in MM. These findings suggest that hsa-miR-23a is a potential therapeutic target for MM deserving further pre-clinical study.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-352. doi:10.1158/1538-7445.AM2011-LB-352
Abstract LB-353: Targeting pancreatic cancer stem cells by epigenetic regulation of miR-34a
Authors: Shankar Sharmila , Srivastava Rakesh
Published: August 2014

MicroRNA-34a (miR-34a) is a transcriptional target of p53 that is down-regulated in pancreatic cancer. This study aimed to investigate the functional significance of miR-34a on growth of pancreatic cancer stem cells through its epigenetic restoration by chromatin modulators, demethylating agent 5-Aza-2′-deoxycytidine (5-Aza dC) and HDAC inhibitor Suberoylanilide hydroxamic acid (Zolinza/vorinostat/SAHA). Re-expression of miR-34a in pancreatic cancer stem cells and pancreatic cancer cell lines on treatment with 5-Aza dC and SAHA strongly inhibited the cell proliferation, cell cycle progression, self renewal, epithelial to mesenchymal transition and invasion. miR-34a upregulation of by 5-Aza dC and SAHA in pancreatic cancer stem cells (PCSC's) also induced apoptosis by activating caspase 3/7. Modulation of miR-34a expression inhibited the protein expression of its putative target genes Bcl-2, CDK6, Cdc25, SIRT1, which was rescued by inhibiting miRNA-34a in the presence of miR-34a antagomir. miR-34a upregulation also induced acetylated p53, p21WAF1, p27, and PUMA protein levels in PCSC's. Interestingly treatment of PCSC'c with 5-Aza dC and SAHA resulted in the inhibition of epithelial -mesenchymal transition by downregulating N-Cadherin, Zeb-1, a crucial inducer of EMT, Slug and Snail expression and also by transcriptional upregulation of E-Cadherin. SAHA retards in vitro cancer stem cell migration and invasion by the inhibition of Notch signaling pathway. Inhibition of miR-34a by antogomiR abrogates the effects of SAHA and 5-Aza dC, suggesting that SAHA and 5-Aza dC regulate stem cell characteristics in PCSC's through miR-34a. The present study thus demonstrates the role of miR-34a as a critical regulator of pancreatic cancer progression. The restoration of miR-34a expression by 5-Aza dC and SAHA in human primary pancreatic cancer stem cells and cell lines will not only provide mechanistic insight and therapeutic targets for pancreatic cancer but also promising reagent to boost patient response to existing chemotherapies or as standalone cancer drug by the elimination of the cancer stem cells characteristics.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-353. doi:10.1158/1538-7445.AM2011-LB-353
Abstract LB-357: HIF-dependent over-expression of CUB domain-containing protein 1 stimulates migration in clear cell renal cell carcinoma
Authors: Razorenova Olga V. , Finger Elizabeth C. , Colavitti Renata , Chernikova Sophia B. , Boiko Alexander D. , Chan Charles KF , Krieg Adam , Bedogni Barbara , LaGory Edward , Weissman Irving L. , Broome-Powell Marianne , Giaccia Amato J.
Published: August 2014

Kidney cancer is the sixth leading cause of cancer death in the USA, and the primary tumor is frequently accompanied by metastasis to lungs, liver, brain and bones. Importantly a large number of kidney cancer cases are characterized by loss of von Hippel-Lindau (VHL) gene, which leads to stabilization of hypoxia-inducible factors (HIFs), which contribute to tumor progression and metastasis by multiple mechanisms. CUB-domain-containing protein 1 (CDCP1) was shown to be expressed on the cell surface of metastatic cell lines and to increase the number of nodules formed by lung adenocarcinoma cells and melanoma in lungs in tail vein injection experiments, enhance peritoneal dissemination of scirrhous adenocarcinoma, and to induce metastasis in the chicken embryo metastatic model. In the present study we investigated the role of CDCP1 protein in clear cell renal cell carcinoma (CC-RCC) and found it to be upregulated in this disease entity by a mechanism of VHL loss through HIFs. Interestingly, we found CDCP1 protein expressed not only on the membrane of kidney cancer cell lines, but also to be secreted into the media as a full length isoform. Importantly, in the knockdown experiments we found CDCP1 to promote CC-RCC cell migration in vitro, the process known to be the key during metastasis. Accordingly CDCP1 participates in the signal transduction pathway leading to PKCδ phosphorylation in CC-RCC, stimulating migration. The role of PKCδ in CDCP1-dependent migration was verified by the PKCδ knockdown experiments, which phenocopy the effect of CDCP1 knockdown; as well as migration rescue experiments, where the impairment of migration caused by CDCP1 downregulation was rescued by the overexpression of constitutively active mutant of PKCδ. Furthermore, we showed a correlation of CDCP1 cell surface expression in primary tumor with poor patient outcome. Finally, we found that suramin, a drug, which showed the clinical benefit for CC-RCC patients at premetastatic stages, causes the downregulation of CDCP1 at the protein level. Thus, the further investigation of the role of CDCP1 protein in kidney cancer metastasis is important to validate CDCP1 as a therapeutic target.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-357. doi:10.1158/1538-7445.AM2011-LB-357
Abstract LB-364: G(alpha)12 is required for thromboxane A2 to regulate tumor cell motility
Authors: Malik Babar , Zhang Xuejing , Nie Daotai
Published: August 2014

Introduction: Thromboxane (TX) A2 is a prostaglandin produced by metabolism of arachidonic acid through cyclooxygenase and thromboxane synthase. TXA2 is biologically active, mainly through activating its cognate, seven transmembrane, G protein coupled receptor. We previously reported that thromboxane A2 receptor (TP) was expressed in prostate cancer, and further activation of this receptor elicited cell contraction and modulated tumor cell motility through regulating small GTPase RhoA (Nie et al., Cancer Res 68: 115–121, 2008). This study aims to identify G alpha protein(s) involved in thromboxane A2 signaling in tumor cell motility.

Methods: The expression of G alpha proteins in the PC3MM cells was studied by real-time PCR. Cell contraction assay was performed by staining cells with TRITC phalliodin and evaluated under an epifluorescence microscope. Tumor cell motility and invasion were evaluated using wound healing assay and transwell Boyden Chamber assay. To determine the roles of G alpha protein in thromboxane A2 signaling, we expressed different alleles of G alpha proteins (wild type, constitutive active) in PC3MM cells and then the subsequent effects on cell contractions was determined. We also depleted G alpha protein expression by short hairpin RNA and examined subsequent changes in cell contraction and migration after activation of TP.

Results: PC3 MM cell line had the endogenous level of all the G alpha protein (G alpha 12, G alpha i1, G alpha 11, G alpha 13), but not G alpha q. Overexpressionof G alpha 12/13 increased cell contraction after activation of thromboxane A2 receptor with U46619. Expression of constitutively active G alpha 12 by itself was sufficient to cause cell contraction, regardless whether TP is activated or not. Depletion of G alpha 12 via shRNAs reduced cell contraction after TP activation. Tumor cells with G alpha 12 depleted had tumor cell motility and invasiveness.

Conclusion: The findings indicate that G alpha 12 is required for TP to induce cell contraction and to regulate tumor cell motility. The studies suggest G alpha 12 may be a promising target of intervention to reduce tumor cell motility and metastasis in prostate cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-364. doi:10.1158/1538-7445.AM2011-LB-364
Abstract LB-369: A novel aniline derivative enhances radiosensitivity of lung cancer through suppression of Nrf2 activity
Authors: Ahn Jiyeon , Lee Saelooom , Lim Min-Jin , Kim Mi-Hyoung , Yu Chi-Ho , Yun Yeon-Sook , Song Jie-Young
Published: August 2014

The major obstacle in radiotherapy or chemotherapy is the resistance of cancer cells to the therapies. Nuclear factor erythroid-2-related factor 2 (Nrf2) is a redox-sensitive transcription factor that regulates antioxidant enzymes. Kelch-like ECH-associated protein (Keap1) sequesters Nrf2 and leads to proteasomal degradation of Nrf2 in non-stressed condition. Keap1 is often found with biallelic mutation in non-small cell lung cancer (NSCLC) cell lines and NSCLC patients, results in constitutive activation of Nrf2 function, and contributes to resistance to anticancer drugs. Therefore, we aimed to develop small molecules that inhibit Nrf2 activity to maximize radiation-induced cell death via increasing ROS generation. A cell-based high-throughput screening using luciferase assay, we have identified an aniline derivative (IM3829) as a radiosensitizer of lung cancer in vitro and in vivo. In clonogenic assay, this compound sensitized H1299 lung cancer cells to irradiation.

IM3829 with irradiation significantly increased ROS accumulation compared with radiation alone treated cells, leading to apoptotic cell death synergistically. IM3829 inhibited Nrf2 binding activity and HO-1 expression. In H1299 xenografts mice, IM3829 with radiation significantly inhibits tumor growth by 47 % and 27 % compared with vehicle or radiation alone treated animals, respectively. Our finding suggested that IM-3829 could be a promising radiosensitizer in lung cancer patients, particularly those with a high expression of Nrf2.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-369. doi:10.1158/1538-7445.AM2011-LB-369
Abstract LB-371: Evaluating the protein SUMOylation pathway as a potential cancer therapeutic target using inducible RNA interference
Authors: He Xingyue , Bence Neil , Dick Larry , Veiby Petter , Bolen Joe
Published: August 2014

Protein SUMOylation is a conserved ubiquitin-like protein posttranslational modification pathway catalyzed by the SUMO enzymatic cascade. Previous studies have indicated SUMO pathway genes are highly expressed in cancer and are required for development and cell viability. We applied lentivirus based shRNA methods to efficiently knockdown SUMO pathway components in human cancer cells. shRNAs for SAE2 and UBC9 lead to reduced SUMO pathway activity as measured by cell based reporter assays. Knockdown of SUMO enzymes suppresses proliferation of human cancer cells including U2OS, HCT116 and HeLa cells. Multiple shRNAs for each gene showed a similar growth arrest phenotype suggesting that the results are not RNAi off target effects. Furthermore, SUMO pathway inhibition by RNAi sensitize U2OS cells to the DNA damage agent Camptothecin, indicating a chemo-sensitizing effect of SUMO pathway inhibition. To improve the reproducibility of our experiments and avoid an observed negative selection for the constitutively expressed shRNAs, we established a doxycycline inducible conditional shRNA (tet-on) system to achieve acute and reversible SUMO enzyme knockdown. Acute SAE2 knockdown in U2OS and HCT116 cells reduces S phase and slows cell growth in vitro. Our data demonstrate SUMO pathway is a potential therapeutic target to treat cancer and this study demonstrates that inducible shRNA systems are valuable for early stage drug discovery.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-371. doi:10.1158/1538-7445.AM2011-LB-371
Abstract LB-372: Expression and functional role of erbB2 in human hepatoblastoma
Authors: Steiger Barbara , Leuschner Ivo , Denkhaus Dorota , von Schweinitz Dietrich , Pietsch Torsten
Published: August 2014

The receptor tyrosine kinase erbB2 is known to play a role in the development of hepatic progenitor cells and is often found to be expressed and mutated in different solid tumors. Activated erbB2 is a marker of poor prognosis in several malignancies and to date, successful strategies have been developed to target erbb2 receptor. The aim of this study was to determine the expression of erbb2 in human hepatoblastoma, the most common primary hepatic malignancy in early childhood, and its functional role in hepatoblastoma cell biology. Expression of erbB2 on the protein level was analyzed by Western Blot, immunofluorescence and RT-PCR of lysates of primary tumors and cell lines HuH6, HepT1, HepT3 and HepG2. Immunohistochemical staining was performed to determine phosphorylated erbB2 and subsequent kinases. Single strand conformation polymorphism (SSCP) analysis was used to scan known hotspots for mutations (exons 6, 8, 18–23 of erbB2) in a panel of 56 tumor samples. Cells were stimulated with rhHRG1-β. Activation of subsequent kinases was determined via Western Blot and MTT assay was used to determine proliferation after stimulation and overexpression of erbb2 via transient transfection. The influence of rhHRG1-β on the activity of the Wnt/ß-catenin pathway was measured by transfection with the TOP-/FOP-Flash reporter assay. The effects of erbB2 kinase knockdown by transient transfection with siRNA against erbB2 on apoptosis and proliferation were also evaluated. Expression of erbB2 was detected in all four cell lines and most of the primary tumors. Immunohistochemistry indicated expression of phosphorylated (activated) Erbb2 proteins in 90% and activation of subsequent kinases, which are downstream targets of erbb2. Mutations were not present in the erbB2 gene. Stimulation with HRG1-β induced phosphorylation of Akt, Erk1/2 and p70S6K and resulted in increased cell proliferation. This effect was not mediated by an increase of activity of the Wnt/ß-catenin signaling pathway because TOP-Flash reporter activity was not further increased in the presence of rhHRG1-β. Overexpression of erbB2 resulted in enhanced proliferation after stimulation with HRG1-β in all four cell lines, whereas knockdown of erbB2 decreased the proliferative effect of HRG1-β on hepatoblastoma cell lines. Knockdown of erbB2 did not induce apoptosis in hepatoblastoma cell lines. These results indicate that erbB2 might play an important functional role in hepatoblastoma cell biology. Further experiments are needed to evaluate the clinical significance.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-372. doi:10.1158/1538-7445.AM2011-LB-372
Abstract LB-373: Lymphatic vessels and neoformed microvessels density in primary oral squamous cell carcinoma and associated lymph nodes
Authors: Sousa Sílvia F. , Gleber-Netto Frederico O. , Oliveira-Neto Helenisa H. , Batista Aline C. , Gomes Carolina C. , Gomez Ricardo S. , Aguiar Maria Cássia F.
Published: August 2014

The aim of this study was to evaluate the density of lymphatic vessels (LVD) and neoformed microvessels (MVD) in primary oral squamous cell carcinoma (OSCC) and associated lymph nodes, metastatic or not, and the association of such densities with clinicopathological behavior and metastasis presence. Since vascular endothelial growth factor C (VEGF-C) induces tumor lymphangiogenesis and lymphatic metastasis, this protein was also analyzed in tumor parenchyma. For evaluation of primary tumor, thirty-six paraffin-embedded samples of OSCC were investigated. The tumors were histologically graded and all clinical data of the patients, as tumor size and nodal metastasis were obtained from the medical records. Intratumoral and peritumoral lymphatic (LVD) and neoformed (MVD) vessels were identified by immunohistochemistry using D2–40 and CD105 antibodies respectively. The sum of intra and peritumoral lymphatic and neoformed microvessels was determined as total LVD and total MVD in a magnification of 400x. The same method of count was applied in the analysis of vascular density in lymph nodes. The immunoexpression of VEGF-C was determined by percentage of strongly positive tumour cells. Intratumoral lymphatic vessel density mean was 2.95±3.30, peritumoral mean was 2.96±2.23 and total LVD mean was 5.86±4.81. MVD intratumoral mean was 7.40±4.55, peritumoral mean was 6.25±3.92 and total MVD mean was 13.66±7.30. Intratumoral LVD was significantly lower in poor differentiated tumors (p<0,05). Total MVD was higher in cases with lymph node involvement (p<0.05). An association between VEGF-C positivity and metastasis was also observed (p<0,05). The LVD and MVD in metastatic lymph nodes were significantly higher than in non metastatic lymph nodes (p<0,001). In conclusion lower LVD and higher MVD were associated with high grade malignancy and presence of metastasis. In addition, the metastatic lymph nodes demonstrated a significantly higher vascular density comparatively to non metastatic lymph nodes and the influence of this finding in occurrence of distance metastasis should be investigated in further studies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-373. doi:10.1158/1538-7445.AM2011-LB-373
Abstract LB-386: Targeting of induced cancer stem cells with iniparib in combination with carboplatin and gemcitabine
Authors: Ossovskaya Valeria , Canino Erica , Giritharan Gnanaratnam , Kim Kyung-Ah , Ilic Dusko , Krtolica Ana
Published: August 2014

BACKGROUND: Mounting evidence exists that human breast cancers include a stem-like cell population with self-renewing, tumorigenic properties. This population of cells, known as cancer stem cells (CSCs) or tumor-initiating cells, shares phenotypic characteristics with embryonic stem cells (ESCs), including activation of certain developmental pathways, and is resistant to many anticancer therapies. Distinguishing features of stem cells include active DNA repair and resistance to apoptosis, which enable their survival in the presence of conventional cytotoxic and cytostatic therapies that target actively proliferating cells. Identification of pharmaceuticals that preferentially target CSCs represents a novel strategy in modern drug discovery and development. We investigated whether treatment with iniparib (BSI-201) can potentiate the anti-proliferative effects of gemcitabine and carboplatin in CSCs.

METHODS: A multi-stage stem cell carcinogenesis model that mirrors the natural progression of carcinogenesis was previously developed using in vitro and in vivo selection of mutated ESCs, which exhibit specific tumor-initiating and cancer stem cell-associated behaviors (SLL Sciences). These induced CSCs (iCSCs) were treated with iniparib (3.7, 11, 33, or 100 μM), gemcitabine (1.5 nM), carboplatin (10 μM), or gemcitabine + carboplatin for 72 hours, and effects on iCSC proliferation were evaluated using an ELISA-based bromodeoxyuridine (BrdU) assay and an ATP-based detection assay for measuring cellular metabolism. Effects of iniparib and/or gemcitabine on DNA damage were evaluated by immunofluorescence staining of iCSC using antibodies against γH2AX (a marker of double strand DNA breaks) at 24 hours after treatment.

RESULTS: Treatment with iniparib alone resulted in a dose-dependent decrease in cellular proliferation and metabolism, with the IC50 established at 60 μM. Iniparib (60 μM), gemcitabine (1.5 nM), and carboplatin (10 μM) each induced >50% reduction in iCSC proliferation; addition of iniparib to gemcitabine resulted in an 80% reduction in BrdU incorporation compared with gemcitabine alone (P = 0.027). To assess iniparib-associated DNA damage, γH2AX foci were quantified in > 300 cells for each treatment combination. Cells treated with iniparib, gemcitabine, or iniparib + gemcitabine demonstrated 3.7-, 6.8-, and 8.8-fold increases in γH2AX foci, respectively, compared with untreated control (P < 0.005).

CONCLUSIONS: These findings demonstrate that iniparib increases the effects of gemcitabine in terms of antiproliferative activity and DNA damage in this CSC model.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-386. doi:10.1158/1538-7445.AM2011-LB-386
Abstract LB-387: Blockade of the CXCL12/CXCR4 axis with AMD3100 induces multimodal antitumor effects in murine ovarian cancer and prolongs survival
Authors: Kashiwagi Satoshi , Righi Elda , Yuan Jianping , Santosuosso Michael , Ingraham Rachel , Orsulic Sandra , Birrer Michael , Penson Richard , Dranoff Glenn , Poznansky Mark C.
Published: August 2014

The chemokine, CXCL12, and its receptor, CXCR4, have been shown to be expressed by various tumors including ovarian cancer. CXCL12/CXCR4 expression by tumors has been associated with enhanced progression including tumor cell proliferation, invasion, and angiogenesis. We proposed that modulation of the CXCL12/CXCR4 axis in ovarian cancer would have multimodal effects on tumor pathogenesis. This was addressed using RNAi technology and a selective CXCR4 antagonist, AMD3100, in an immunocompetent mouse model of intraperitoneal papillary epithelial ovarian cancer derived from a syngeneic cell line (BR5–1) that constitutively expresses both CXCL12 and CXCR4. CXCL12 knockdown of BR5–1 cells using RNAi reduced cell proliferation in vitro (p<0.01) and tumor growth in vivo (p<0.05) compared to controls. AMD3100 treatment of BR5–1-derived tumors resulted in the increase of tumor apoptosis (p<0.05)and necrosis and in a significant reduction of intraperitoneal dissemination, angiogenesis, and intratumoral infiltration of FoxP3+ regulatory T cells compared to controls (T-regs)(p < 0.05). In addition, selective CXCR4 blockade with AMD3100 resulted in significantly increased anti-tumor T cell mediated immune responses compared to controls (p<0.05). These multimodal anti-tumor effects translated into a significant survival advantage in AMD3100-treated mice as compared to controls (p<0.05). Selective CXCR4 antagonism also significantly decreased intratumoral T-regs infiltration in a second model of aggressive melanoma (p<0.05). In summary, these data generated in an immunocompetent syngeneic and orthotopic murine model of ovarian cancer lend important support to the view that the CXCL12/CXCR4 axis plays multiple roles in the pathogenesis of this disease. Furthermore, the availability of a safe, effective and clinically applicable CXCR4 antagonist in AMD3100 adds both to the direct clinical translatability of this study and to the potential for the use of this agent as an adjunct to conventional chemotherapy or in combination with other immunotherapies aimed at enhancing CD8+ T cell responses in human ovarian cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-387. doi:10.1158/1538-7445.AM2011-LB-387
Abstract LB-392: JunB and cJun dependent PDGFRβ expression reveals imatinib/nilotinib treatment as effective therapeutic strategy for ALK driven lymphomas.
Authors: Schiefer Ana Iris , Kenner Lukas
Published: August 2014

Anaplastic large cell lymphomas (ALCLs) are frequent non Hodgkin Lymphomas of T-cell origin, comprising 40% of all non-Hodgkin Lymphomas of childhood and 2–8% of adulthood. Half of the cases are associated with a t(2;5) translocation, leading to the fusion of NPM gene and ALK tyrosine kinase, resulting in its constitutive activation. The AP-1 transcription factors JunB and cJun are downstream effectors of NPM-ALK. To investigate the role of JunB and cJun in NPM-ALK mediated tumorgenesis, we used a murine NPM-ALK T- cell lymphoma model in which the conditional deletion of JunB and cJun was selectively restricted to CD4+ T lymphocytes. Loss of JunB and cJun in transgenic T cells resulted in significantly increased disease latency and doubled the mean survival rate. We identified PDGFRβ as direct target of cJun and JunB. These transcription factors directly bind to a highly conserved AP-1 site within the promoter region of PDGFRβ and activate its transcription in vitro. We further investigated the effects of PDGFRβ inhibition in NPM-ALK xenografts and in a murine NPM-ALK T-cell lymphoma model using the kinase inhibitors imatinib and nilotinib. Treated xenografts showed significant smaller tumor masses, CD4-NPM-ALK mice displayed a drastic increase in mean survival rate. Based on these very promising data we even had the chance to check effects of imatinib therapy in a patient with relapsed ALK+ ALCL. After treatment with six cycles CHOP, one cycle ICE, allogenic stem cell transplantation with previous conditioning with BEAM, he received imatinib. Within one week of therapy lymph nodes regressed and B-symptoms declined. A PET-CT revealed complete remission two weeks after imatinib initiation. In summary, these data demonstrate a pathogenic role of JunB/cJun as well as PDGFRβ in NPM-ALK mediated lymphomagenesis. Our study encourages the development of specific clinical trials for human ALCLs using tyrosine kinase inhibitors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-392. doi:10.1158/1538-7445.AM2011-LB-392
Abstract LB-395: Hepatocyte growth factor: a potential therapeutic target in pancreatic cancer
Authors: SJ Arun , Z Xu , Fiala-Beer E , Phillips P , Goldstein D , Biankin A , Pirola R , Wilson JS , Apte MV
Published: August 2014

Pancreatic stellate cells (PSCs, which produce the desmoplastic reaction of pancreatic cancer) interact with pancreatic cancer (PC) cells to potentiate PC progression. A candidate factor that may mediate this interaction is the hepatocyte growth factor (HGF). High serum HGF levels in PC patients correlate with poor outcome. However, there is limited knowledge about the role of HGF in PC. Aims: To i) determine whether human PSCs and PC cell lines express HGF; and

ii) assess the effects of HGF inhibition on PC progression in an orthotopic mouse model.

Methods:

i) HGF expression in PSCs and PC cells assessed by RT-PCR, immunoblotting/immunocytochemistry.

ii) Orthotopic model: AsPC-1 (a human PC cell line) ± human PSCs implanted into the pancreas mice. One week later, mice divided into groups (n=8 mice/group) and treated with: HGF antibody AMG102 [(Amgen Inc.), 300 or 600μg IP biweekly] or isotype IgG (600 μg IP biweekly). Seven weeks later, tumour size and metastasis assessed.

Results:

i) PSCs express HGF at both mRNA and protein levels. In contrast, PC cells (MiaPaCa2, Panc-1, AsPC-1) express negligible HGF mRNA.

ii) Orthotopic model: a) IgG treated AsPC-1+PSC mice showed larger tumours than mice injected with AsPC-1 alone (Table); b) 300 and 600μg AMG102 inhibited tumour growth in AsPC-1+PSC mice compared to the IgG treated group. However, AMG102 did not reduce tumour size in mice injected with AsPC-1 alone (Table). c) 600μg AMG102 inhibited metastasis (liver, diaphragm, mediastinum) in AsPC-1+PSC mice (p<0.05) compared to IgG treated mice.

Conclusions: We have shown for the first time that i)human PSCs synthesise HGF; ii)HGF inhibition reduces tumour growth and metastasis of tumours representative of human PC i.e., exhibiting both tumour elements and a stromal reaction, but not in the clinically non-representative cancers formed by PC cells alone.

Implication: Targeting the stromal reaction with relevant specific inhibitors may represent a novel therapeutic approach in PC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-395. doi:10.1158/1538-7445.AM2011-LB-395
Abstract LB-397: Functional characterization of IGF-1R antibodies and possible implications for clinical safety and efficacy
Authors: Kuenkele Klaus-Peter , Hofmann Marco H. , Scheiblich Stefan , Wartha Katharina , Klein Christian
Published: August 2014

Background

This is the first study performing a head to head comparison of monoclonal IGF-1R antibodies (mAb) based on published sequences for therapeutic mAbs from Pfizer (CP751,871, IgG2 kappa), Amgen (AMG479, IgG1 lambda), Merck (h7C10, cloned to R1507 backbone), Imclone (IMC-A12, IgG1 lambda) and Roche (R1507, IgG1).

Methods

In this study, sequence information for IGF-1R mAbs was extracted from patents and used to clone and transiently express IgGs (*=re-synthesized) in HEK293F cells. In vitro assays for ligand binding, IGF-1R auto-phosphorylation, IGF-1R downregulation, IR co-downregulation, and affinity analyses (Biacore) were used. In vivo comparison was done in BxPC3 xenograft mouse model.

Results

All antibodies inhibit IGF-1 binding and signaling at low nanomolar levels. While IMC-A12* and R1507 also prevent IGF-2 binding to IGF-1R and subsequent receptor activation, CP751,871* and h7C10* do not inhibit IGF-2 binding and have only limited impact (55%/30% inhibition) on IGF-2 signaling.

Analysis of IGF-1R phosphorylation in 0.5 % FCS medium revealed that all antibodies except R1507 exert agonistic activity. Interestingly, Fab fragments of agonistic mAbs became antagonistic, indicating that bivalent binding is necessary for agonistic effects.

All mAb (200nM, 24h treatment of MCF-7 cells) with the exception of AMG479* efficiently downregulated 78–82% the IGF-1R. Analysis of the same cell lysates revealed however striking differences in IR co-downregulation, a mechanism discussed as possible cause of clinical hyperglycemia. R1507 had the least side effects on Insulin co-downregulation (9%) compared to h7C10* (15%), CP751,871* (23%) and IMC-A12* (46%).

Differences were also seen in the binding kinetics. Both AMG479* and R1507 showed faster koff rates resulting in shorter retention times at the receptor. Since kon/koff rates are discussed to influence tumor penetration (1), we compared downregulation of IGF-1R by R1507 and CP751,871* in xenograft tumors. Although both mAbs downregulate IGF-1R in vitro to the same extent, R1507 was significantly more effective in the in-vivo setting.

Conclusion

The head to head comparison of IGF-1R mAbs revealed differences in regard to binding properties, tumor penetration, IR codownregulation, and inhibition of signaling via the ligand IGF-2.

Reference List

1. Adams, G. P., Schier, R., McCall, A. M., Simmons, H. H., Horak, E. M., Alpaugh, R. K., Marks, J. D., and Weiner, L. M. (2001) Cancer Res. 61, 4750–4755

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-397. doi:10.1158/1538-7445.AM2011-LB-397
Abstract LB-40: Autophagy prevents leukemogenesis by protecting normal hematopoietic stem cells from transforming to leukemia stem cells
Authors: Yuan Na , Wang Qi , Zhang Aihong , Lin Weiwei , Liu Lei , Zhang Suping , Cao Yan , Xu Fei , Kong Yue , Li Lanzi , Xu Tiehan , Chen Si , Lu Tongyuan , Zhao Wenli , Zhang Xueguang , Wang Jianrong
Published: August 2014

Leukemia has long been considered unpreventable, and how leukemogenesis is initially triggered remains largely unknown. We observed that autophagy is frequently downregulated in the hematopoietic stem cells of various types of leukemia patients. Using a conditional Becn1 knockout mouse model, we found that impaired autophagy results in rapid accumulation of reactive oxygen species (ROS) that causes DNA damages, genome instabilities and chromosomal translocations of hematopoietic stem cells, leading to their transformation to leukemia stem cells, ultimately attributed to various leukemogenenesis. Restoration of autophagy in the hematopoietic stem cells of the autophagy defective mice by constitutive expression of Becn1 could clean up ROS, inhibit DNA damages and chromosomal translocations, and block the transformation of hematopoietic stem cells to leukemia stem cells, ultimately inhibiting leukemogenesis. Furthermore, enhancement of autophagy by rapamycin could effectively remove the ROS experimentally induced in hematopoietic stem cells and eliminate the leukemia stem cells either transplanted to wild-type recipient mice or transformed from normal hematopoietic stem cells due to pharmacological inhibition of autophagy. Our data thus suggest that autophagy prevent leukemogenesis by protecting normal hematopoietic stem cells from transforming to leukemia stem cells and that leukemia prevention is possible by securing autophagy machinery in hematopoietic stem cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-40. doi:10.1158/1538-7445.AM2011-LB-40
Abstract LB-410: Phase I dose escalation study of MM-121, a fully human monoclonal antibody to ErbB3, in patients with advanced solid tumors
Authors: Denlinger Crystal S. , Keedy Vicki L. , Cleary James M. , Kubasek William , Onsum Matthew , Moulis Sharon , Garcia Gabriela , Schoeberl Birgit , MacBeath Gavin , Nering Rachel , Murray James , Moyo Victor , Wong Kwok-Kin , Shapiro Geoffrey
Published: August 2014

Introduction: ErbB3 has been identified as a key driver of the PI3K/AKT signaling pathway, resulting in cell growth and survival. MM-121 is a fully human monoclonal antibody targeting ErbB3. By binding to ErbB3, MM-121 blocks heregulin, thereby inhibiting ligand-induced ErbB3 heterodimerization and activation of receptors. Binding of MM-121 also induces downregulation of ErbB3 from the cell surface.

Methods: Patients ≥ 18 years with refractory advanced solid tumors were given MM-121 weekly in 4-week cycles at 6 dose levels. Dose escalation was based on dose limiting toxicities (DLTs) during cycle 1. Primary objectives were to determine the maximum tolerated dose (MTD) of MM-121 and describe any objective response and progression free survival. Secondary objectives were to describe the safety, pharmacokinetic (PK), and pharmacodynamic profile of MM-121. A dose expansion cohort at the highest dose cohort was also included for selected tumor types, with required pre- and post-treatment biopsies to assess MM-121 target effects, ErbB3 pathway markers, and guide dose schedule decisions.

Results: Between July 2008 to January 2011, 38 patients have been enrolled in the study. Twenty-five patients were enrolled in the dose escalation part of the study and treated until unacceptable toxicity or progression. Six cohorts were completed and an MTD was not reached. Grade 1/2 nausea, diarrhea, fatigue and rash were the most commonly observed adverse events. Grade 1 hypomagnesemia was observed in 4 patients at different doses. One patient experienced a DLT of confusion at the lowest dose, considered possibly related to MM-121 treatment but confounded by other comorbidities. No other treatment related serious AEs were reported. An additional 13 patients have been enrolled to date in an expansion cohort. The overall safety profile for patients in the expansion cohort is similar to that observed for the dose escalation cohorts.

Conclusion: In this single agent, first in human, dose escalation phase I study MM-121 was well tolerated with a favorable safety profile. Enrollment in the dose expansion cohort is ongoing.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-410. doi:10.1158/1538-7445.AM2011-LB-410
Abstract LB-416: Evaluation of phase 3 multicenter clinical data of receptor targeted (CD206) Tc99m-tilmanocept for sentinel node evaluation (ILM) in breast cancer and melanoma
Authors: Sondak Vernon K. , Wallace Anne M.
Published: August 2014

Background: Sentinel lymph node (SLN) mapping is widely used for staging clinically node-negative breast cancer and melanoma. [99mTc]tilmanocept is a new receptor-targeted (CD206) radiopharmaceutical designed for SLN mapping. The purpose of this review is to report the results of the Phase 3 clinical data designed to assess the concordance of [99mTc]tilmanocept with vital blue dye, considered the standard for identifying sentinel lymph nodes in these two malignancies.

Methods: The Phase 3 program was a multicenter, prospective, open label, evaluation of [99mTc]tilmanocept in patientswith clinically localized melanoma or breast cancer. Within the Intent-to-treat population, [99mTc]tilmanocept and vital blue dye were administered to patients and standard SLN mapping was performed, during which all identified radioactive and/or blue-stained lymph nodes were excised and histologically examined. The primary endpoint was concordance of [99mTc]tilmanocept with vital blue dye. The patient concordance rate was defined as the percentage of patients for whom all nodes detected by blue dye were also detected by [99mTc]tilmanocept.

Results: At least one blue-stained lymph node was exhibited by 91% patients and 98.0% had at least one “hot” node. The concordance of [99mTc]tilmanocept with vital blue dye was statistically significant with ∼98% concordant. Of the melanoma patients, ∼97% were concordant; and within the breast cancer patients, ∼99% were concordant. In contrast, vital blue dye had a concordance rate with [99mTc]tilmanocept of <55%. No severe adverse events were related to the administration of [99mTc]tilmanocept.

Conclusions: [99mTc]Tilmanocept was well tolerated and effectively identifies sentinel nodes with a statistically significant degree of concordance to blue dye in either breast cancer or melanoma surgery. Additional outcomes will be presented. (Also refer to ClinicalTrials.gov, key word, tilmanocept)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-416. doi:10.1158/1538-7445.AM2011-LB-416
Abstract 101: Pilot study of oral microbiome and risk of pancreatic cancer.
Authors: Lin I-Hsin , Wu Jing , Cohen Steven M. , Chen Calvin , Bryk Darren , Marr Mollie , Melis Marcovalerio , Newman Elliot , Pachter H Leon , Alekseyenko Alexander V. , Hayes Richard B. , Ahn Jiyoung
Published: August 2014

Previous studies showed that periodontitis and tooth loss are associated with increased risk of pancreatic cancer, suggesting possible role of oral bacteria in the pancreatic cancer etiology. We evaluated whether oral microbiome is associated with risk of pancreatic cancer and pancreatitis.

Oral wash samples were collected from 13 pancreatic cancer patients, 3 pancreatitis patients and 12 healthy controls at NYU Langone Medical Center, New York. Ribosomal 16S rRNA genes from oral wash DNA were amplified by universal primers, barcoded, and sequenced with 454 FLX technology. The bacterial 16S rRNA gene sequences were binned into operational taxonomic units (OTUs) with 97% identify and further classified by taxonomy. Non-parametric Wilcoxon Mann Whiteney U test and Kuskal-Wallis test were conducted to compare the relative abundance of taxa across pancreatic cancer, pancreatitis and control groups.

A total of 250,008 sequence reads (average 8,928 reads per sample) were observed. Firmicutes, Bacteroidetes, and Actinobacteria are major phyla, accounting for 96.5% of oral microbiota. We found that bacteroides genus was significantly more abundant in both pancreatic cancer patients (p = 0.002) and pancreatitis patients (p = 0.004) compared with control group. Further, BLAST search results indicate that the species most closely represented by the Bacteroides OTUs were oral pathogen. In addition, Corynebacterium (p = 0.033) and Aggregatibacter (p = 0.019) were less abundant in pancreatic cancer and pancretitis groups compared with controls.

Data from this pilot study of oral microbiome and pancreatic cancer suggest that the differential abundance in bacteriodates and possibly Corynebacterium and Aggregatibacter, are associated with risk of pancreatic cancer. Bacteroides, Gram-negative bacillus bacteria, plays an important role in oral inflammation, including periodontitis. Further larger studies are warranted to confirm these preliminary findings.

Citation Format: I-Hsin Lin, Jing Wu, Steven M. Cohen, Calvin Chen, Darren Bryk, Mollie Marr, Marcovalerio Melis, Elliot Newman, H Leon Pachter, Alexander V. Alekseyenko, Richard B. Hayes, Jiyoung Ahn. Pilot study of oral microbiome and risk of pancreatic cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 101. doi:10.1158/1538-7445.AM2013-101