bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1341: Early detection of tumor cells by innate immune cells leads to Treg recruitment through CCL22 production by tumor cells
Authors: Faget Julien , Biota Cathy , Bachelot Thomas , Gobert Michael , Dezutter-Dambuyant Colette , Treilleux Isabelle , Goddard-Leon Sophie , Blay Jean Yves , Caux Christophe , Menetrier-Caux Christine
Published: February 2011

We recently obtained evidences, in breast carcinoma, that regulatory T cells (Treg) localized within lymphoid aggregates, but not in the tumor bed, have a negative impact on patients’ survival. Immunohistochemical analysis on paraffin embedded sections of tumors demonstrated correlation between CCL22 production tumor cells and Treg infiltration thus identifying CCL22 as a key mediator of intratumoral Treg recruitment (Gobert M., Cancer Res vol 69, p2000-9, 2009). Herein we decipher the mechanisms regulating CCL22 production by tumor cells.

In vitro, human breast epithelial tumor cell lines secreted low CCL22 levels that were strongly increased in response to inflammatory signals (TNFα, IFNγ and IL-1β or their combination). Using an in vitro model we demonstrated that breast tumor cell lines (MCF-7, MDA-MB453, CLB-SAV, BT-474) but not immortalized normal breast epithelial cell line (Telma) secreted functional CCL22 in response to culture with PBMC or their supernatants. Addition of IL-1RA and anti-TNFα abrogated the CCL22 secretion demonstrating the importance of Il-1β and TNFα in CCL22 production. Depletion experiments demonstrated a major role of monocytes within PBMC in i) the induction of CCL22 and ii) the production of IL-1β and TNFα. However, co-culture of tumor cells with purified monocytes was not sufficient to reproduce the PBMC effects. The addition of rhIFNγ to tumor cell and monocyte co-cultures restored the CCL22 production by tumor cells and that of IL-1β by monocytes suggesting a role of IFNγ producing cells (T cells or NK cells) within PBMC.

Taken together, these results demonstrate a dialogue between monocytes, tumor cells and IFNγ producers (NK or T cells) leading, through monocyte-derived IL-1β and TNFα, to CCL22 production by tumor cells and Treg recruitment. These observations would suggest that early tumor cell detection by innate effectors (monocytes, NK) would trigger CCL22 production by tumor cells and not normal mammary epithelial cells leading to Treg recruitment as a mechanism to stop the anti-tumor immune reactivity.

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 1341.
Abstract 1344: TGFß, an inflammation and immune suppressor in tumor microenvironment and progression
Authors: Yang Li , Pang Yanli , Yan Hannah , Li Zhaoyang , Achyut BR
Published: February 2011

Alterations in TGFβ signaling have significant effects on tumor initiation and progression. TGFβ functions both as a tumor suppressor and as a tumor promoter. Most work so far to dissect mechanisms underlying this dual role of TGFβ has been largely focused on differential regulation of signaling pathways by tumor autonomous TGFβ signaling. Studies from our lab demonstrate that TGFβ significantly regulate inflammation in tumor microenvironment and host immune response. When TGFβ R2 receptor is deleted in mammary cancer epithelial cells, there was an increased inflammation and recruitment of Gr-1+CD11b+ myeloid cells, which leads to increased tumor invasion and metastasis. This infiltration of Gr-1+CD11b+ cells also results in increased abundance of TGFβ1 and metalloproteinase activity in tumors with Tgfbr2 deletion. Interestingly, Tumor-infiltrating Gr-1+CD11b+ cells exhibited significant elevated TGFß signaling including increased expression of RI and RII receptor, TGFß1 and TGFß3 ligands, as well as latent transforming growth factor ß binding protein when compared with normal myeloid cells. Genetic deletion of Tgfbr2 in myeloid cells significantly attenuated 4T1 breast carcinoma tumor growth and metastasis. This is accompanied with significantly increased IFNγ production in the lungs of tumor bearing mice. These data suggest that TGFß, the tumor suppressor, also functions as an inflammation and immune suppressor. TGFß signaling in host derived myeloid cells is an important mediator in tumor immune surveillance. This new understanding of TGFß in inflammation and immune response in the interface of tumor and host may provide insight information for TGFß switch from a tumor suppressor to a tumor promoter.

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 1344.
Abstract 1349: Ablation of E2f3 in macrophages reduces the incidence of lung metastasis
Authors: Trikha Prashant , Pena Clarissa , Sharma Nidhi , Reyes Andreas , Leone Gustavo
Published: February 2011

The tumor stroma is predominantly composed of cells of the immune system, one of them are the tumor-associated macrophages (TAMs). Tumor macrophages are recruited to the tumor in response to cytokines secreted by the tumor epithelial cells. TAMs secrete proteases into the extracellular matrix (ECM) that contributes to tumor cell intravasation. Rb-E2F axis represents one of the important pathways involved during cell cycle and is deregulated in number of cancers. E2Fs have distinct roles in the control of cell proliferation, apoptosis and differentiation pathways. We have previously shown that E2F are important downstream targets in CSF-1 signaling cascade that are involved in macrophage survival and proliferation. Present study is aimed at exploring the link between conditional ablation of E2f3 in TAM and its effect on lung metastasis using MMTV-PyMT mouse model of breast cancer. Ablation of E2f3 in the tumor macrophages resulted in a reduction of lung metastasis without affecting tumor onset or macrophage numbers. Microarray analysis of E2f3 deleted TAMs showed an up-regulation in expression of genes involved during metastasis. Our results show that E2f3 regulates the physiological processes in TAMs that inhibit lung metastasis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1349.
Abstract 135: Apoptotic cell death triggering in the prostate carcinoma cell line PC3 by the anoikis effector Bit1
Authors: Biliran Hector R. , Leleux Kelly E. , Eubanks Jolisha S. , Ireland Shubha K.
Published: February 2011

Highly aggressive cancer cells often are associated with resistance to caspase-dependent apoptosis, due, in part to loss in function or mutation in caspase effectors. Such apoptotic defects in caspase signaling pathway may provide a selective growth advantage for tumor cells and potentiate their aggressiveness and resistance to chemotherapeutic agents. Here, we test the responsiveness of the highly aggressive prostate cancer cell line PC3 cells to the apoptotic function of the novel, caspase-independent anoikis effector Bcl2 inhibitor of transcription (Bit1). Overexpression of the cytoplasmic localized Bit1 in PC3 cells results in significant induction of apoptosis as evidenced by the increased levels of histone-DNA fragments. Furthermore, PC3 cells transfected with the mitochondrial localized Bit1 exhibit significant apoptosis following loss of cell attachment as compared to vector treated cells, and such induction of anoikis is associated with increased levels of Bit1 in the cytosol. In contrast, both the control and Bit1 transfected PC3 cells show the same level of spontaneous apoptosis when grown attached to a culture dish. We also tested whether Bit1 alters the chemoresistant phenotype of PC3 cells. Consistent with the induction of anoikis sensitivity, overexpression of mitochondrial Bit1 also renders PC3 cells more sensitive to etoposide-induced apoptosis. Interestingly, the Bit1-mediated apoptosis in PC3 cells is correlated with increased NFkappa B activity as evidenced by increased nuclear translocation and transcription factor activity of the p65 subunit. Taken together, these findings indicate that activation of the caspase-independent Bit1 apoptotic pathway may serve as a preferred alternate approach in triggering apoptosis in aggressive prostate cancer cells. Bit1 may thus serve as a future therapeutic target for the treatment and alleviation of the chemoresistance characteristic of 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 135.
Abstract 1369: A novel anti-angiogenic vector with vascular disrupting activity as a promising treatment for metastatic cancer
Authors: Breitbart Eyal , Bangio Livant , Harats Dror , Greenberger Shoshana , Varda-Bloom Nira
Published: February 2011

A novel anti-angiogenic vector with vascular disrupting activity as a promising treatment for metastatic cancer

Breitbart E1, Greenberger S2, Varda-Bloom N2, Bangio L1, Harats D1

1VBL Therapeutics, Or Yehuda, Israel, 2Sheba Medical Center, Ramat Gan, Israel

Background: A major drawback of current approaches to cancer therapy is the lack of tissue-specific targeting. We have developed both tissue and condition-specific expression vascular targeting system (VTS) platform directed to areas in which angiogenesis is taking place, without perpetually harming the body's healthy tissues, to destroy these newly formed blood vessels of solid tumors. We have constructed VB-111 as a vascular disruptive (VDA) and anti-angiogenic agent.

Results: In vitro, VB-111 induced a dose dependent apoptotic death in HUVEC but not in non endothelial cells confirming its specificity. In a comprehensive set of in vivo studies employing the Lewis Lung metastasis mouse model, VB111 was safe and specific with activity only in the metastatic lesion themselves. VB-111 induced a dose dependent reduction of 90% in tumor burden of lung metastases with one injection and similar efficacy in other tumor models. Evaluation of the activity of Sutent in Lewis lung metastasis model showed better efficacy of VB-111 as compared to Sutent 40 or 80 mg/kg. Additive effect was reached when mice were treated with VB-111 and Doxorubicin 2.5mg/kg.

Conclusions: Collectively, our studies demonstrate that VB-111 is safe and specific. VB111 shows a dual action of anti-angiogenic and vascular disruptive agent. VB-111 has the potential to be utilized as a relatively broad-spectrum anticancer agent efficacious in different types of solid tumors. These findings have prompted us to proceed to clinical trials that are reported elsewhere.

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 1369.
Abstract 137: Targeting IAPs: NF-κB signaling pathways play a critical role in IAP antagonist induced apoptosis
Authors: Varfolomeev Eugene , Goncharov Tatiana , Vucic Domagoj
Published: February 2011

Inhibition of apoptosis enhances the survival of cancer cells and facilitates their escape from immune surveillance and cytotoxic therapies. Inhibitor of apoptosis (IAP) proteins are anti-apoptotic regulators that block cell death in response to diverse stimuli. Because these proteins play an active role in promoting tumor maintenance, they are attractive targets for developing a novel class of cancer therapeutics. Through TRAF2 interactions, c-IAP1 and c-IAP2 are recruited to tumor necrosis factor receptor 1 (TNFR1)-associated protein complexes where they regulate receptor-mediated signaling. The ubiquitin E3 ligase activity of c-IAP1/2 regulates canonical and noncanonical NF-κB pathways by promoting ubiquitination of RIP1 and NIK. We have designed small-molecule IAP antagonists that bind with high affinities to select baculovirus IAP repeat (BIR) domains of IAPs resulting in a dramatic induction of c-IAP auto-ubiquitination and rapid proteasomal degradation. Neutralization of c-IAPs through knockdown or small-molecule IAP antagonists blunts TNF stimulated NF-κB activation and greatly sensitizes cells to TNF induced cell death. Investigation of death receptor signaling complexes revealed that FLIP plays an important role in IAP antagonist stimulated apoptotic pathways and that down-regulation of FLIP sensitizes otherwise resistant cells to IAP antagonist induced cell death. In addition, regulation of NF-kB signaling pathways by cellular IAPs represents a pivotal point in IAP antagonists induced cell death. The interplay between pro-survival and pro-apoptotic signaling involves multiple levels of coordination and the regulation of these processes can determine the fate of treated cells. Finally, our IAP antagonists inhibit tumor growth in vivo as single agents and in combination with a number of standard of care anti-tumor agents including death receptor agonists. Interestingly, while single-agent activity of IAP antagonists relies on TNF signaling, the synergistic activity of IAP antagonists with FasL or anti-DR5 antibody does not depend on TNF signaling but on XIAP antagonism. Understanding the significance of protein stability and death receptors mediated pathways for inhibition of apoptosis by IAP proteins is important for the design of potent IAP-directed compounds. These compounds can be used in the treatment of malignancies in which IAP expression contributes to tumor progression and resistance to conventional chemotherapeutic agents.

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 137.
Abstract 1376: Antiangiogenic properties of the peptide CIGB-300
Authors: Farina Hernán G. , Acero Fernando Benavent , Perera Yasser , Rodríguez Arielis , Perea Silvio , Castro Boris Acevedo , Gomez Roberto , Alonso Daniel F. , Gomez Daniel E.
Published: February 2011

CK2 is a highly conserved protein serine/threonine kinase that is ubiquitously distributed in eukaryotes, constitutively active and has been implicated in multiple cellular functions, as well as in tumorigenesis and transformation. Elevated CK2 activity has been associated with the malignant transformation of several tissues and is associated with aggressive tumor behavior. Previously, we have described a peptide CIGB-300 (also named P15-Tat) targeting the acidic phophorylation domain of the CK2 substrates. Different groups around the world have tried to manipulate this biochemical event by targeting the ATP-binding site of CK2 or its gene transcription using antisense oligonucleotides. Otherwise, CIGB-300 peptide was developed following the innovative approach of targeting the phosphoaceptor site on the CK2 substrates rather than the enzyme per se. We demonstrated that CIGB-300 induced apoptosis on tumor cells and tumor regression when injected directly into solid tumors or by systemic administration in mice.

In this work we have evaluated the CIGB-300 peptide on the angiogenic process, both in vitro and in vivo. We have focused in the exploration of CIGB-300 properties to inhibit proliferation, tube formation and RNA pattern expression on endothelial cells (HUVEC). Likewise we used the chicken chorioallatoic membrane (CAM) assay as a model in vivo to asses the CIGB-300 activity on angiogenesis. Others authors have studied the role of different CK2 inhibitors on angiogenesis finding that CK2 is involved in endothelial cell proliferation, survival, migration and tube formation. Intraperitoneally administered CK2 inhibitors significantly reduced preretinal neovascularization in a mouse model of proliferative retinopathy. Solid tumors require the growth of new blood vessels (angiogenesis) to grow. Tumor angiogenesis utilizes at least some of the angiogenic signalling pathways that are required during vascular development. Tumor angiogenesis has become an important target for antitumor therapy, with most current therapies aimed at blocking the VEGF pathway. However, not all tumors are responsive to VEGF blockers, and some of them that are responsive initially may become resistant during the course of treatment, thus there is a need to explore other angiogenesis signalling pathways.

In this paper we have examined the antiangiogenic properties of CIGB-300 peptide in vitro and in vivo. The data suggests that CK2 is involved in angiogenic processes and CIGB-300 could act as promising antiangiogenic inhibitor.

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 1376.
Abstract 1378: Preclinical efficacy of the triple VEGFR inhibitor tivozanib (AV-951) in chimeric breast and lung tumor models
Authors: Zhou Yinghui , Zi Tong , Bressel Angela , Jesmer Kristen , Potz Darren , Monti Anthony , Brodeur Joelle , Rideout William , Chiu Maria Isabel , Robinson Murray O. , Heyer Joerg
Published: February 2011

All solid tumors are thought to require neo-vascularization. Therefore pharmacologic inhibition of angiogenesis may represent an important component for treating many therapeutically challenging tumor types. One attractive anti-angiogenesis agent is the ATP competitive small molecule VEGFR inhibitor tivozanib (AV-951). Tivozanib exhibits picomolar inhibitory activity against all three VEGF receptors, a multi-day T1/2 in humans, and demonstrates robust clinical activity in renal cell carcinoma, the signal tumor type for VEGF pathway inhibition. To test preclinical efficacy of tivozanib in other cancer types, we chose primary mouse tumor models due to their ability to capture the complex heterotypic interactions between tumor cells and the microenvironments. Our mouse tumor model strategy involves stepwise genetic manipulation of embryonic stem (ES) cells and chimera formation to enable direct tumor induction in tissues containing both normal and engineered cells. A HER2 driven breast model as well as an allelic series of lung cancer models containing EGFR, KRAS, or HER2 oncogenes demonstrated that resultant adenocarcinomas arose within surrounding normal tissue and exhibited features of advanced malignancies.

In this study, we tested the response of HER2 driven breast tumors as well as KRAS and EGFR driven lung tumors to the VEGFR inhibitor tivozanib in tumor bearing chimeric mice. We observed that although tivozanib treatment conferred significant survival benefit to the tumor bearing mice in all three models, it is not able to eradicate all tumor cells. Response to tivozanib in the breast model is much more heterogeneous than in the lung models, with some tumors exhibiting significant regression while others showing progression on treatment, either initially or after a period of response. In contrast, lung tumors showed more uniform response to tivozanib treatment initially, but tumors quickly grew back upon discontinuation of tivozanib treatment. These results indicate that both breast and lung cancer patients could potentially benefit from sustained anti-angiogenesis therapy, and combination of anti-angiogenesis with tumor targeting agents may be required for enduring 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 1378.
Abstract 1379: Impact of tumor blood flow modulation on sensitivity of 9L gliosarcoma xenografts to the bioreductive drug, AQ4N
Authors: Manley Eugene , Waxman David J.
Published: February 2011

The bioreductive drug AQ4N is reduced enzymatically under hypoxic conditions to yield AQ4, a cytotoxic metabolite and topoisomerase II inhibitor. This study tests the hypothesis that the two electron reductase DT-diaphorase (NQO1) contributes to AQ4N reduction and that modulation of tumor hypoxia increases AQ4N activity in vivo. A panel of human and rodent tumor cells was assayed for AQ4N sensitivity under normoxic and hypoxic conditions (0.1% O2 for 24 hr), followed by 3 days culture under normoxia without drug. 9L rat gliosarcoma and H460 lung carcinoma, but not 10 other tumor cell lines, exhibited substantially higher (≥ 8 fold) AQ4N sensitivity under hypoxic culture conditions. Investigation of the impact of the DT-diaphorase inhibitors dicumarol and flavone-8-acetic acid on AQ4N cytotoxicity and examination of the cell line dependence of DT-diaphorase protein expression indicated that this enzyme does not contribute to AQ4N cytotoxicity. Next, we investigated whether AQ4N chemosensitivity could be increased by modulating tumor hypoxia in s.c. 9L and H460 tumors implanted in immunodeficient mice. In mice treated with the vasodilator hydralazine, tumor hypoxia was significantly increased in 9L, but not H460 tumors, as determined by pimonidazole staining. Hydralazine also decreased tumor perfusion to a greater extent in 9L tumors than H460 tumors, as judged by uptake of Hoechst 33342. However, hydralazine-induced 9L tumor hypoxia did not increase AQ4N mediated tumor growth delay, in either scid or nude mouse models. Furthermore, combination of AQ4N treatment with inhibition of VEGF receptor-dependent angiogenesis, which increases tumor hypoxia in 9L xenografts, did not augment anti-tumor activity beyond that of VEGF receptor inhibition alone. These findings suggest that the enhancement of AQ4N cytotoxicity in these tumors requires a level of tumor hypoxia that is more extensive or prolonged that can be achieved using these vasodilators and anti-angiogenic agents. Supported in part by NIH grant CA49248 (to D.J.W.).

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 1379.
Abstract 1382: The sea cucumber-derived anti-cancer triterpenoid, Frondoside A blocks angiogenesis
Authors: Collin Peter D. , Adrian Thomas E.
Published: February 2011

We have previously shown that an extract (B1000) of the epithelial layer of the Atlantic sea cucumber, Cucumaria frondosa inhibited cancer cell proliferation. A pure triterpenoid glycoside, Frondoside A was purified from this extract, and has shown potent growth inhibitory effects, both in vitro and in vivo in pancreatic, colon, prostate, and breast cancer cells but no effect on normal cells. The present studies were aimed at investigating the effects of Frondoside A on angiogenesis. The parent sea cucumber extract, B1000, has marked anti-angiogenic effects in the chick chorioallantoic membrane (CAM) assay. B1000 virtually eliminated vasculature in this model (B1000 mean score of 3.8±0.1; hydrocortisone/heparin positive control: 3.2±0.1, P<0.001, where a score of 3 = almost complete inhibition of vasculature and 4 = complete inhibition). The anti-angiogenic effects of B1000 were confirmed in the endothelial tube formation assay employing human umbilical vein endothelial cells (HUVEC) on matrigel coated slides. B1000 also inhibited migration of C8161 melanoma cells and RA116 synovial fibroblasts in a membrane invasion culture system. Based on these data, we investigated the effect of pure Frondoside A on the ability of HUVEC cells to differentiate into capillary-like structures. At a concentration of 1µM, Frondoside A virtually abolished endothelial tube formation (88±6% inhibition, P<0.0001) and was more than ten-fold more potent than the Suramin positive control in this assay (74±3% inhibition at 10µM). This was not due to cytotoxicity, since the HUVEC cells were viable in the culture, however, they failed to form the tube-like structures seen in control.

These findings indicate that Frondoside A has anti-angiogenic effects in addition to its cancer growth-inhibitory effects. B1000 and Frondoside A may be valuable in the prevention or treatment of solid tumors.

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 1382.
Abstract 1383: The effect of a novel angiogenesis inhibitor (TM) on the efficacy of HSV-1 oncolytic virus
Authors: Kaka Azeem , Pradarelli Jason C. , Alvarez-Breckenridge Christopher , Yoo Ji Young , Pan Quintin , Chiocca E. Antonio , Old Matthew , Teknos Ted , Kaur Balveen
Published: February 2011

Oncolytic viruses (OVs) are modified viruses specifically designed to lyse cancerous cells while leaving surrounding tissue intact. Solid tumors such as glioma represent an excellent candidate for this novel cancer therapy. We are investigating barriers towards oncolytic viral therapy in vivo. The tumor microenvironment plays an inhibitory role in viral propagation and spread. In particular, the angiogenic and inflammatory response that follows OV inoculation have been demonstrated to significantly limit OV efficacy. The goal of our current project is to determine if the novel copper-chelating angiostatic/anti-inflammatory drug, tetrathiomolybdate (TM), represents a potential co-therapy that can be used in conjunction with OV to enhance overall efficacy in a glioma model. Based on previous findings from our laboratory, the anti-cancerous effects of oncolytic viruses can be significantly increased by pre-treatment with an angiostatic agent. Apart from supporting angiogenesis, copper found in serum has also been shown to inhibit wild-type HSV infection and replication. Due it its copper chelating properties, TM has been FDA approved for Wilson's disease and is currently under clinical investigation for efficacy as an angiostatic and antineoplastic agent. Here we tested if copper can inhibit OV mediated glioma cell killing. 1): We found a significant and dose dependant inhibitory effect of copper on the cytotoxic ability of OV against multiple glioma and head and neck SCC cells. 2): The inhibitory effects of copper were apparent even at physiologically relevant concentrations of copper (1 mg/L in serum). 3): Further we found that Cu mediated inhibition of OV killing of glioma cell could be rescued by TM mediated copper chelation. 4): Finally we have tested that TM does not interfere with viral replication or tumor cell killing properties in vitro. Given the potential angiostatic and anti-inflammatory properties of TM, these studies support further in vivo testing of TM in conjunction with oncolytic viral therapy. 5): We are currently testing therapeutic efficacy of combining TM and OV for anti-glioma efficacy 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 1383.
Abstract 1391: Inhibition of Hsp90 induces BRCA1 degradation and hypersensitivity to ionizing radiation
Authors: Stecklein Shane R. , Harlan-Williams Lisa M. , Wang Wenjia , Eskew Jeffrey D. , Chaguturu Vamsee , Jensen Roy A.
Published: February 2011

Cells expressing high levels of breast cancer susceptibility gene 1 (BRCA1) are resistant to ionizing radiation and alkylative chemotherapeutic agents. Ablation of BRCA1 expression in vitro and in vivo can enhance and/or restore sensitivity to these agents.

BRCA1 is a nuclear phosphoprotein that is critical for resolving double-strand DNA (dsDNA) breaks. Thus, its overexpression likely confers an advantage to cancerous cells targeted by anti-neoplastic agents that induce this form of DNA damage. In vitro evidence suggests that ablating BRCA1 expression may present a novel mechanism to enhance or restore radio- and chemosensitivity in refractory cancers. Like BRCA1, high expression of heat shock protein 90 (Hsp90) has been associated with resistance to radiotherapy and chemotherapy, though the mechanism(s) behind this phenotype are poorly characterized. Hsp90 is a cytoplasmic chaperone that is upregulated or exists in a hyperfunctional state in many human malignancies. Previous studies have demonstrated that Hsp90 regulates the assembly of several molecules involved in the homology-directed repair of dsDNA breaks, including BRCA2/FANCD1, FANCA, MRE11/RAD50/NBS1 (MRN), and RAD51. Using in vitro culture of breast, ovarian, and colorectal cancer cell lines, we demonstrate that inhibition of Hsp90 by the pharmacologic agent 17-allylamino-17-demethoxygeldanamycin (17-AAG), which is currently in clinical evaluation, targets BRCA1 for ubiquitylation and proteasome-mediated degradation. Furthermore, inhibition of Hsp90 and the subsequent loss of BRCA1 expression are associated with decreased repair of ionizing radiation-induced DNA damage and increased tumor cell death. Using lentiviral shRNA expression, we also demonstrate that loss of BRCA1 is epistatic to the ability of 17-AAG to sensitize cells to the effects of ionizing radiation, consistent with the central role of BRCA1 in assembling the dsDNA break repair machinery.

These results suggest that inhibition of Hsp90 using an existing therapeutic agent (17-AAG) may be an effective mechanism to transiently inhibit BRCA1 expression and improve or restore radio- and/or chemosensitivity in breast and ovarian 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 1391.
Abstract 140: XIAP expression in non-small cell lung cancer cells is a key determinant of threshold to TRAIL-induced apoptotic cell death
Authors: Yang Jianhui , Xie Yili , Witasp Erika , Kwong King F.
Published: February 2011

Background: Intrinsic resistance to apoptosis-induction by TRAIL is found in the majority of non-small cell lung cancers (NSCLC). Previously, we have shown that intrinsic TRAIL-resistance in NSCLC cells can be markedly attenuated by transient transfection of siRNA directed against XIAP, and accordingly rendering TRAIL-resistant NSCLC cells restored TRAIL-sensitivity, with markedly enhanced apoptosis rates. The objective of the current study is to investigate the effects of XIAP overexpression in intrinsically TRAIL-sensitive lung cancer cells with respect to its threshold to apoptotic cell death.

Methods: Lentiviral p-Receiver-lv19-XIAP (GeneCopoeia, Rockville, MD) were transduced in cultured human NSCLC H460 cells to generate stable clones. Subsequently, p-Receiver-lv19-XIAP-H460 cell colonies were screened for optimal vector expression and XIAP overexpression and then propagated in culture for further analysis. Parental H460 and negative control H460-p-empty stable clone cells were used for comparisons. p-Receiver-lv19-XIAP-H460 stable clones, negative control H460-p-empty stable clones, and H460 parental cells were cultured with and without administration of TRAIL. Also, XIAP overexpression stable clones were treated with TRAIL alone, Smac mimetic AEG40730 (Vibrant Pharma, Inc., Ontario, CN), or their combination. Cellular proliferation was measured using MTT assays. Caspase activation was evaluated using Western blot analysis and caspase activity was quantified by fluorescence caspase assays.

Results: p-Receiver-lv19-XIAP-H460 stable clone cells exhibited a significant increase in protection against TRAIL-induced cell death compared to TRAIL-sensitive parental H460 and H460-p-empty cells across a spectrum of TRAIL concentrations. Also, marked reductions in caspase activation, as a result of decreased sensitivity to TRAIL, were found in p-Receiver-lv19-XIAP-H460 cells despite TRAIL administration. Rescue treatment of p-Receiver-lv19-XIAP-H460 stable clones with combination Smac mimetic AEG40730 and TRAIL was able to negate the effects of XIAP overexpression and restore intrinsic sensitivity to TRAIL-induced cytotoxicity.

Conclusions: TRAIL resistance can be conferred to intrinsically TRAIL-sensitive lung cancer cells via XIAP overexpression alone. The increased threshold to apoptotic cell death is mediated via XIAP's inhibitory effects on the canonical apoptosis pathways. However, TRAIL-sensitivity can be rescued in XIAP overexpressing lung cancer cells by combination treatment with anti-XIAP Smac mimetic and TRAIL administration. These results, along with previous work, demonstrate that XIAP is a key determinant of apoptotic cell death in lung cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 140.
Abstract 141: Identification of a gene silenced in rat mammary carcinomas by combination of DNA methylation microarray and chemical genomic screening
Authors: Hattori Naoko , Okochi-Takada Eriko , Yamashita Satoshi , Watanabe Naoko , Ushijima Toshikazu
Published: February 2011

Aberrant DNA methylation is deeply involved in the development and progression of human breast cancers, but its inducers and molecular mechanisms are still unclear. To reveal such inducers and analyze molecular mechanisms of methylation induction, animal models are indispensable. However, genes methylation-silenced in the animal models of breast cancer are unknown, and identification of inducers and analysis of mechanisms are hampered.

Here, to identify genes methylation-silenced in rat primary mammary carcinomas, we took a combined approach of methylated DNA immunoprecipitation (MeDIP)-CpG island (CGI) microarray and chemical genomic screening. MeDIP-CGI microarray analysis of a carcinoma cell line induced by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) revealed that, among 4,680 promoter CGIs analyzed, 664 were methylated in the cell line. Sixty-two of the 664 genes were re-expressed by treatment of the cell line with 5-aza-2’-deoxycytidine and trichostatin A. An unmethylated status in normal mammary glands was confirmed for 31 of the 62 genes by MeDIP-CGI microarray analyses of a pool of 4 normal mammary glands. Among 13 primary mammary carcinomas induced by PhIP, five of the 31 genes were methylated in one carcinoma or more. Among 12 primary carcinomas induced by 7,12-dimethylbenz[a]anthracene, methylation of all the five genes was also observed. RT-PCR analysis revealed that one of the five genes had high expression in normal mammary glands, but low expression in carcinomas, showing that this gene was methylation-silenced in rat primary mammary carcinomas.

In humans, the gene was expressed in mammary epithelial cells that had unmethylated DNA, and was down-regulated in three cancer cell lines that had methylated DNA. The gene was methylated in about 9% of 80 primary human breast cancers, and it was suggested that aberrant DNA methylation of this gene was a common event between rat and human breast cancers.

This is the first study of genome-wide DNA methylation analysis using rat mammary carcinomas, and the methylation-silenced gene, along with the other methylated genes, is expected to be useful as a marker in identifying inducers of aberrant DNA methylation and analyzing its molecular 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 141.
Abstract 1411: A novel molecular approach for head and neck cancer radiosensitization
Authors: Miyamoto Shunsuke , Wang Hui , Yamashita Taku , Li Daqing , O'Malley Bert W.
Published: February 2011

Purpose:

Current combined external beam radiation therapy (XRT) and chemotherapy have demonstrated as an effective treatment against advanced head and neck cancers. However, combined modality treatments often result in unacceptable levels of toxicity to the patients. It has been well-known that enhanced DNA double strand break (DSB) repairing by Mre11, Rad50 and Nbs1 (MRN) complex is one of the most important mechanisms for developing radioresistance in the tumor cells. The present study investigates if the use of targeted Rad50 disruption could sensitize the tumor cells to XRT for the treatment of human head and neck squamous cell carcinoma (HNSCC). Our goal is to establish a most effective treatment strategy while minimizing XRT morbidity for the HNSCC.

Method:

Two human HNSCC tumor cell lines, JHU012 and JHU022, and an animal model with human HNSCC were used in this study. A dominant-negative recombinant adenoviral vector containing mutant Rad50 (Ad-Rad50) was constructed. The tumors were treated with Ad-Rad50, replication-defective virus (DL312), or untreated as mock control and a 2-Gy XRT. Cell viability and tumor volume were evaluated to analyze anti-tumor activity of different treatment groups. Neutral comet assay was performed for evaluating DNA DSB damage. Apoptosis in tumor cells was studied by using immunohistochemistry.

Result:

Our study demonstrates that the transgene expression of mutant Rad50 significantly interrupts the DNA DSB repairing and increases DNA damage in the tumor cells. Increased levels of tumor cell apoptosis were found associated with combined Ad-Rad50 and XRT treatment group. The combined Ad-Rad50 and XRT treatment shows the best anti-tumor result as compared to other groups both in vitro and in vivo.

Conclusion:

The present study suggests that Ad-Rad50 gene transfer effectively interrupts DNA DSB repairing and results in radiosensitizing in the HNSCC tumor cells treated with XRT. This strategy can be further investigated in the clinic for the treatment of advanced human head and neck 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 1411.
Abstract 1417: Tumour stroma interaction and radiation resistance in pancreatic cancer
Authors: Mantoni Tine S. , Lunardi Serena , Brunner Thomas B.
Published: February 2011

Background

Pancreatic ductal adenocarcinoma (PDAC) is characterised by a strong desmoplasmic reaction where the stromal compartment encounts for up to half the tumour volume. The enriched stroma is believed to be a contributing factor to the poor therapeutic response of PDAC, which is reflected in only 13% surviving the first year after diagnosis. A central mediator of the desmoplastic reaction is the pancreatic stellate cells (PSC). Signalling between PSC and tumour cells stimulates proliferation and migration of both cell types as well as secretion of extracellular matrix (ECM) proteins by the PSC. We aim to gain a better understanding of the crosstalk between PSC and tumour cells and how this affects tumour cell response to ionising radiation.

Methods

We have set up a co-culture system, which allow studies of tumour cells directly and indirectly co-cultured with PSC. Clonogenic survival assays were used to assess the radiosensitivity of mono- and co-cultured tumour cells. We also use in vivo mouse models to study the effects of PSC on tumour proliferation and tumour regrowth in response to radiation.

Results and conclusion

We demonstrate that PSC promote radioprotection and stimulate proliferation in pancreatic tumour cells in both direct and indirect co-culture. This is a PSC specific response as fibroblasts do not have a radioprotective effect on the tumour cells. Our in vivo studies of xenograft tumours in mice likewise demonstrate PSC dependent radioprotection and increased tumour proliferation. The kinetics of DNA repair in tumour cells were investigated but showed no changes in the presence of PSC and was therefore concluded not to form part of this radioprotective response. Previous studies have shown that cell adhesion to ECM proteins by integrin molecules mediates resistance to genotoxic stress. We here show that abrogating β1-integrin signalling by means of a blocking antibody results in a significant decrease in the PSC mediated radioresistance in tumour cells. Taken together we here demonstrate for the first time that PSC promote radioprotection of pancreatic tumour cells in vitro and in vivo. Our data points towards a role of β1-integrin signalling in this radioprotective response.

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 1417.
Abstract 1420: Inhibition of platelet-derived growth factor receptor tyrosine kinase reduces tumor growth and metastasis in an orthotopic nude mice model of human gastric cancer
Authors: Sumida Tomonori , Kitadai Yasuhiko , Onishi Mayu , Ohara Eiji , Shinagawa Kei , Tanaka Miwako , Kodama Michiyo , Tanaka Shinji , Yasui Wataru , Chayama Kazuaki
Published: February 2011

Background: Recent studies have revealed that platelet-derived growth factor (PDGF) plays a role in promoting progressive tumor growth in several organs; however, whether PDGF plays a role in gastric cancer is undetermined. We examined whether inhibition of PDGF receptor (PDGF-R) tyrosine kinase signaling by imatinib affects tumor growth and metastasis of human gastric cancer cells in an orthotopic nude mouse model.

Methods: TMK1 human gastric cancer cells were injected into the gastric wall of nude mice. Groups of mice (n=10 each) received saline (control), low-dose imatinib (50 mg/kg/day), high-dose imatinib (200 mg/kg/day), cancer chemotherapeutic agent irinotecan (5 mg/kg/week), or imatinib (50 mg/kg/day or 200 mg/kg/day) and irinotecan in combination for 28 days. Tumor growth and metastasis were assessed. Resected tumors were analyzed immunohistochemically.

Results: Carcinoma-associated fibroblasts (CAFs) within gastric tumors expressed high levels of PDGF-R; cancer cells did not. Treatment with imatinib alone did not inhibit tumor growth and metastasis; however, treatment with irinotecan alone or combined with imatinib (single-agent therapy or relative control) significantly inhibited tumor growth. Only treatment with high-dose imatinib and irinotecan in combination inhibited lymph node and peritoneal metastasis. Immunohistochemically, only imatinib alone or in combination with irinotecan significantly decreased the stromal reaction, pericyte coverage of tumor microvessels, and microvessel area. These effects were marked in the high-dose imatinib group.

Conclusion: Administration of PDGF-R tyrosine kinase inhibitor in combination with irinotecan appears to impair the progressive growth of gastric cancer cells by blockade of PDGF-R signaling pathways in CAFs and pericytes on the tumor vasculature.

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 1420.
Abstract 1425: Dasatinib reverses the phenotype of cancer associated fibroblasts (CAFs) to a normal fibroblast (NAF) like phenotype
Authors: Schmid Jens O. , Haubeiss Silke , Mürdter Thomas E. , Friedel Godehard , van der Kuip Heiko , Aulitzky Walter E.
Published: February 2011

Cancer associated fibroblasts (CAFs) show a molecular and functional phenotype that is different from their normal counterparts (normal fibroblasts, NAFs). It is a well established phenomenon that these modified and activated fibroblasts possess permissive and promoting properties for epithelial tumor cells and therefore play a central role in tumor progression, metastasis, and probably also in sensitivity to antitumor agents. We asked whether CAFs could be reverted back pharmacologically to normal homeostasis by inhibiting PDGFR signalling.

We therefore evaluated the efficacy of the FDA approved PDGFR inhibitor Dasatinib on proliferation and gene expression profile of CAF strains isolated from different lung carcinoma specimens. Dasatinib significantly reduced proliferation without inducing cell death in all 40 CAF strains investigated. Genome-wide microarray analysis of 9 CAF strains cultivated in presence or absence of Dasatinib identified 491 genes whose expression was significantly changed at least twofold. 104 of these encoded cell cycle related proteins with a great majority of 97 being down-regulated by Dasatinib. To determine the relevance of the differentially regulated genes in Dasatinib treated cells, we compared the Dasatinib expression signature to the previously described signatures of NAFs and CAFs derived from breast cancer patients (Sadlanova et al., 2008). Importantly, 102 of the 491 genes regulated by Dasatinib were also shown to be differentially expressed in CAFs versus NAFs. The expression of 72 of the genes we identified as down-regulated by Dasatinib was also reduced in NAFs compared to CAFs (p<0.0001 in Fisher's exact analysis). In addition, 30 genes identified as up-regulated by Dasatinib were also found to be elevated in NAFs compared to CAFs (p<0.0001 in Fisher's exact analysis).

In summary, our data suggest that Dasatinib may reverse the cancer-activated phenotype of CAFs to a normal fibroblast like phenotype. Dasatinib treatment may therefore also reverse the tumor-promoting properties of CAFs.

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 1425.
Abstract 143: Global DNA methylation level in whole blood and risk of non-Hodgkin lymphoma
Authors: Kim Hee Nam , Tran Huong Thi Thanh , Li Yu , Kim Nan young , Lee Il-Kwon , Kim Yeo-Kyeoung , Yang Deok-Hwan , Lee Je-Jung , Shin Min–Ho , Park Kyeong-Soo , Chung Ik-Joo , Cho Sang-Hee , Choi Jin-Su , Hyeoung-Joon Hyeoung-Joon
Published: February 2011

Global DNA hypomethylation may result in chromosomal instability and cancer risk. This study was performed to determine the association between DNA hypomethylation in derived from whole blood and non-Hodgkin lymphoma. We analyzed DNA of 506 NHL and 1680 control subjects at Chonnam National University Hwasun Hospital, Korea. Global DNA methylation levels were assessed using bisulfited-PCR pyrosequencing of long interspersed nuclear element-1 (LINE-1). All participants were subsequently categorized into quartiles by mean % in control. When the highest quartile was considered as a reference category (Q4), the following adjusted odds ratios (OR) and 95% confidence intervals (95% CI) were observed for decreasing methylation quartiles OR(Q3)=2.36 (95% CI:1.40-3.97); OR(Q2)=4.67 (95% CI: 2.89-7.55) and OR(Q1)=17.56 (11.19-27.56).

This is, to the best of our knowledge, the first study to show that global DNA hypomethylation was significantly associated with increased for NHL risk in a large case-control study. These findings suggest that global methylation levels in genomic DNA may be play important role in the NHL risk.

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 143.