changes and it was found that decreased NFțB expression along with the down regulation of PKC resulted in profound expression of Connexin -43 expression. Our study demonstrates the UVB mediated stress signal transduction causes early EMT changes which are hall mark for malignant tissue development and also that these changes were dependant on the NFțB translocation. 111 $ 1RYHO 7XPRU 0RGHO IRU WKH &KDUDFWHUL]DWLRQ RI 2YDULDQ &DQFHU 6SKHURLGV Larissa Marie Uusitalo 1 and Nadine Hempel 1 1 SUNY Albany Ovarian cancer, the leading cause of mortality in gynecological malignancies, possesses a unique capacity to metastasize to surrounding tissues by forming multicellular aggregates that are distributed throughout the peritoneum via movement of fluid within the cavity. These aggregates, termed spheroids, experience a unique hypoxic environment containing a variety of circulating growth factors that promote their survival, migration, and invasion of healthy tissues. While 2D cell monolayers are adequate to mimic some aspects of cancer cell dynamics, they do not represent an ideal model for use in the analysis of ovarian cancer metastases. To this end, we are developing a novel 3-D model of ovarian cancer metastasis that reflects the unique properties of spheroid aggregates. By encapsulating cells in cross-linked alginate beads, we are able to provide an environment that promotes aggregation of cells and may facilitate adaptive changes in gene expression leading to the characteristic compaction seen in spheroids isolated from patients’ ascites, not provided by traditional models. We will use this new 3D culture model to study mitochondrial bioenergetics in these cells using the Seahorse XF-24 Extracellular Flux Analyzer and explore the role of hypoxia and reactive oxygen species on spheroid survival, in addition to evaluating the effectiveness of chemotherapeutic treatments on spheroids established from cell lines representing predominant forms of the disease. Using this new tool to analyze spheroid characteristics, we will have the opportunity to further current knowledge about and improve treatment modalities for ovarian cancer metastases. 112 $VFRUEDWH ,V D 5DGLRVHQVLWL]HU LQ 3DQFUHDWLF &DQFHU Jessemae L. Welsh 1 , Juan Du 1 , Zita A. Sibenaller 1 , Amanda L. Kalen 1 , Brett A. Wagner 1 , Bryan G. Allen 1 , Douglas R. Spitz 1 , Prabhat C. Goswami 1 , Garry R. Buettner 1 , and Joseph J. Cullen 1 1 University of Iowa Pharmacological ascorbate inhibits pancreatic cancer growth by generation of H 2 O 2 . Ionizing radiation (IR) also induces H 2 O 2 formation and subsequent DNA damage. Thus, we hypothesized IR would enhance pharmacological ascorbate-induced cytotoxicity in pancreatic cancer. Pancreatic cancer cell lines MIA PaCa-2, PANC-1, BxPC-3, and AsPC-1 were treated with IR (0 or 3 Gy) with and without ascorbate (0 - 20 mM), and cell viability was determined. Ascorbate enhanced radiosensitivity in all pancreatic cancer cell lines with an average dose modification factor (DMF) of 1.96. Average ascorbate IC 50 for all pancreatic cancer cell lines was 4.2 mM for ascorbate alone vs. 1.6 mM for ascorbate + IR. Analysis of cell lysates for single strand DNA breaks showed increased PARP-1 and PARP-2 with ascorbate, IR, and ascorbate + IR compared to controls. In contrast, analysis for double strand DNA breaks showed increased gamma-H2AX with ascorbate or IR compared to controls and an even greater increase with ascorbate + IR. For in vivo experiments, pre-established MIA PaCa-2 tumors in nude mice were treated with saline control (1 M NaCl i.p. daily), IR (7.5 Gy on days 5 and 8 and 1 M NaCl i.p. daily), ascorbate (4 g/kg i.p. daily), or ascorbate + IR. Treatment with ascorbate + IR inhibited tumor growth compared to controls or ascorbate alone. Ascorbate + IR treatment also increased survival compared to controls, IR, or ascorbate. Analysis of tumor tissue demonstrated increased protein carbonyls and 4-HNE in all treatment groups compared to controls. In conclusion, radiation enhances pharmacological ascorbate-induced cytotoxicity in pancreatic cancer. Ascorbate may be a valuable adjunct to radiotherapy in pancreatic cancer patients with locally advanced disease or after surgical resection. 113 2YHU([SUHVVLRQ RI &DWDODVH (QKDQFHV 7XPRXU &HOO 'HDWK XQGHU +\SR[LF &RQGLWLRQ Kwan Long Mung 1 , Dennis Lam 1 , and Nai Sum Wong 1 1 University of Hong Kong, Hong Kong As a result of a defective vascular supply, cells in solid tumors often exist in an in vivo environment of low oxygen tension with poor supply of nutrients. Tumor cells are thus exposed to a composite form of stress commonly referred to as tumor hypoxia and is a main cause of tumour resistance agaisnt ionization therapy and chemotherapy. Understanding why tumor cells may be able to survive under hypoxic stress will provide a fundamental basis in development of cancer therapies. How low oxygen tension and a lack of nutrients may each contribute to the overall cellular response to stress has not been characterized individually. In this study, the effect of low oxygen tension on the Unfolded Protein Response (UPR) signaling pathways in tumor cells in the presence of an adequate supply of nutrients is examined. At low levels of oxygen both the hyperphosphorylation of PERK and splicing of XBP-1 mRNA were not observed. However, the phosphorylation of eukaryotic initiation factor 2 alpha (eIF2-alpha) and 4EBP-1 was increased and decreased respectively. The over-expression of active catalase but not the inactive mutant in the tumor cells resulted in the enhancement of cell death together with partial prevention of low-oxygen induced phosphorylation of eIF2-alpha. The phosphorylation of 4EBP-1 was not affected. Our findings suggest that low oxygen condition alone is not sufficient for the activation of UPR. Importantly, intracellular ROS (likely to be hydrogen peroxide) in hypoxic tumour cells may play a role in maintaining the survival of tumor cells that involves the phosphorylation of eIF2-alpha. 114 0LWRFKRQGULDO 1XFOHRLG &OXVWHULQJ ,V 5HJXODWHG E\ +  2  3URGXFWLRQ LQ WKH 5HVSLUDWRU\ &KDLQ Lukas Alan 1 , Jaroslav Zelenka 1 , Tomas Spacek 1 , and Petr Jezek 1 1 Academy of Sciences, Prague, Czech Republic DNA intercalators are widely used as anticancer drugs, acting via inhibition of DNA replication. However, patients treated with intercalating drugs are at risk of cardiomyopathy resulting from SFRBM 2012 S52 doi:10.1016/j.freeradbiomed.2012.10.139 doi:10.1016/j.freeradbiomed.2012.10.140 doi:10.1016/j.freeradbiomed.2012.10.141 doi:10.1016/j.freeradbiomed.2012.10.142