bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1086: Discoidin domain receptor 1 contributes to tumorigenesis through modulation of TGFBI expression
Authors: Rudra-Ganguly Nandini , Satpayev Daulet , Lowe Christine , Hu Liping , Randhawa Bally , Chang Mi Sook , Verlinsky Alla , Coleman Jeffrey , Challita-Eid Pia , Yang Peng , An Zili , Morrison Karen , Raitano Art , Pereira Daniel S. , Stover David
Published: August 2012

Discoidin domain receptor 1 (DDR1) is a member of the receptor tyrosine kinase family. It is activated by binding to its ligand, collagen and plays a key role in cell survival, adhesion, migration and invasion. Although DDR1 is present in several normal tissues, it is overexpressed in various cancer types, including lung, colon, ovary and breast tumors as well as in gliomas, where it is known to be associated with poor prognosis. The significance of DDR1 in cancer was illustrated using shRNA silencing, which impaired tumor cell growth, both in vitro and in vivo. Using microarray analysis of tumor cells with DDR1 knockdown, we identified an upregulation of TGFBI expression, which was subsequently confirmed at the protein level. TGFBI is a TGFβ induced extracellular matrix protein secreted by tumor cells and has been reported to act as either a tumor promoter or suppressor, depending upon tumor type. Exogenous addition of recombinant TGFBI to tumor cells inhibited clonogenic growth, recapitulating shRNA data. When grown in vivo as xenografts, the DDR1 knockdown cell lines demonstrated a similar phenotype of reduced growth and tumors exhibited an increase in TGFBI protein levels. In summary, our data suggests that DDR1 expression levels influences tumor growth in part through modulation of TGFBI expression. Ongoing studies will help to understand how DDR1 and TGFBI are linked and contribute to tumorigenesis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1086. doi:1538-7445.AM2012-1086
Abstract 1087: TGF-β activated EGFr as a bypass mechanism for the acquired resistance of MET inhibitors in hepatocellular carcinoma
Authors: Rountree Carl B. , Ding Wei , Dang Hien , Steinway Steve
Published: August 2012

Hepatocellular carcinoma (HCC) patients with an active HGF/c-Met signaling pathway have a significantly worse prognosis. Although targeting strategies using MET tyrosine kinase inhibitors (TKI) are in Phase I/II testing for HCC, monotherapy using TKIs in other cancers has not demonstrated durable responses. In non-small cell lung cancer, bypass mechanisms for resistance to EGFr TKIs include MET amplification and activation. We utilized human HCC MET+ cell lines to explore a mechanism of EGFr activation during MET inhibition, and we examined the effect of combination MET and EGFr TKI therapy on suppressing this bypass mechanism in HCC in vivo. Analysis of 149 HCC specimens using transcriptome profiling and immuno-histochemical staining demonstrates a strong negative correlation between EGFr and MET expression. HCC is predominantly either MET positive [44%] or EGFr positive [45%], and co-expression of MET and EGFr is extremely rare in the same tumor. We have previously demonstrated that treatment of xenograft tumors of human HCC MET+ MHCC97-H cells with a MET TKI resulted in stasis of tumor growth in vivo (You … Rountree. Hepatology. 2011). To understand the mechanism of survival in the MHCC97-H cells after inhibition of MET, we developed an MHCC97-H cell line with stable expression of MET shRNA. This MHCC97-H METneg line demonstrated the slower growth kinetics and the inhibition of both PI3K and MAPK signaling comparable to MET TKI treated xenografts. Screening against 850 kinases and phosphatases identified EGFr activation as a mechanism of survival in this MHCC97-H METneg line. Gene expression analysis of this MHCC97-H METneg cell line demonstrated a 6 fold increase in TGF-β, a ligand of EGFr. MHCC97-H xenograft tumor analysis demonstrates a 20 fold increase in TGF-β expression after MET TKI therapy. In vivo treatment of MHCC97-H tumors with combination MET and EGFr TKI therapy resulted in complete regression of all small tumors (15 mm3 at start of TKI) compared to partial regression when MET TKI was used as monotherapy. Treatment of large tumors (200-300 mm3 at start of TKI) with combination TKI therapy resulted in a significant reduction in tumor volume compared to MET TKI monotherapy. EGFr TKI monotherapy had no effect on tumor growth kinetics. Within MET positive HCC models, MET TKI therapy results in a bypass mechanism through up-regulation of TGF-β and activation of EGFr. This bypass mechanism can be partially overcome with combination EGFr and MET TKI therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1087. doi:1538-7445.AM2012-1087
Abstract 1092: Targeting multiple receptor tyrosine kinases in ovarian cancers
Authors: Ou Wenbin , Jiao Yisheng , Meng Fanguo , Zhou Haimeng , Wang Aiyuan
Published: August 2012

Ovarian cancer is a leading cause of cancer death among women in Western Europe and the United States, which has the highest mortality rate of all gynecologic malignancy. Although more than 70% patients have increased 5-year survival rates after surgery followed by chemotherapy and second-line therapies, the low overall cure rates and the intolerable side effects of systemic chemotherapy asks for the development of novel and more effective pharmacological interventions. The increasing evidences suggest that receptor tyrosine kinase (RTK) activation participates in the oncogenic progression from nonneoplastic mesothelial lining of the ovaries or the fallopian tube epithelium to epithelial ovarian cancer. The RTKs, including EGFR, ERBB2, PDGFR, VEGFR and MET, are activated in subsets of ovarian cancer, suggesting that these kinases might represent novel therapeutic targets. However, clinical trials have not or just partially shown benefit to ovarian cancers treated with EGFR, ERBB2, or PDGFR inhibitors. Despite multiple RTK activation in ovarian cancer pathogenesis, it is unclear whether transforming activity is dependent on an individual kinase oncoprotein or the coordinated activity of multiple kinases. We hypothesized that a coordinated network of multi-RTK activation is important for the tumorigenesis of ovarian cancers. Herein, we demonstrate co-activation of multiple RTKs (EGFR, ERBB2, ERBB4, MET and/or AXL) in individual ovarian cancer cell lines and primary tumors. We also show that coordinate inhibition of this multi-kinase signaling has substantially greater effect on ovarian cancer proliferation and survival, compared to inhibition of individual activated kinases. The inhibition of this multi-RTK signaling by HSP90 suppression results in profound pro-apoptotic and anti-proliferative effects, and is associated with the inactivation of RTK downstream PI3-K/AKT/mTOR and RAF/MAPK signaling. These studies suggest that anti-multiple RTK strategy could be useful in the treatment of ovarian cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1092. doi:1538-7445.AM2012-1092
Abstract 1097: MicroRNA expression in white blood cells of CML patients: Differential expression in responders and non-responders to imatinib
Authors: Bruhn Oliver , Diewock Tobias , Pott Christiane , Kneba Michael , Cascorbi Ingolf , Haenisch Sierk
Published: August 2012

Introduction: Treatment of chronic myeloid leukemia (CML) with the BCR/ABL-inhibitor imatinib led to a tremendous progress of over-all survival. However therapy resistance in a significant proportion of patients remains a severe clinical problem. Aside mutations of the BCR/ABL gene, regulation of cellular transporters or downstream factors may contribute to non-response. We aimed to investigate micro-RNA expression profiles in peripheral leukocytes of 21 newly diagnosed CML patients without BCR/ABL-mutations in order to identify biomarkers to treatment-response of imatinib. Methods: Ten responders (molecular remission) and 11 non-responders were included. Expression of 667 microRNAs was analyzed using a TaqMan Low-Density Array system. Relative fold change of microRNAs between groups was calculated according to the 2^-ΔΔCt method. MicroRNAs with a fold change>2 and a P-value<0.01 were considered significant. MicroRNAs with minor expression (Ct-value>20) were not included. Putative targets of dysregulated microRNAs were considered, if predicted by at least three databases, and further analyzed using the DAVID-bioinformatic database. Results: Four microRNAs were significantly deregulated (miR-7, miR-744*, miR-616, miR-212) between responders and non-responders, when being treatment-naïve, predicted to have 97 potential targets. In depth target analysis showed that transcription regulators (21% of the predicted targets) are highly enriched compared to normal gene expression background of humans. Pathway analysis revealed six genes involved in cancer pathways, whereas four of them are directly involved in the chronic myeloid leukemia pathway (SMAD4, NRAS, RB1, RAF1). In responders seven microRNAs were deregulated before and after therapy, whereas five other microRNAs were deregulated within the group of non-responders. Three deregulated microRNAs were identified in both groups. Most predicted target genes are involved in MAPK signaling and exocytosis, 13% of the targets were predicted to be transcription regulators, and 18% cellular (especially uptake) transporters. Conclusion: We identified distinct microRNA pattern comparing blood samples of responders and non-responders prior to imatinib therapy. Predicted target genes were primarily transcription factors and oncogenes. In contrast, transporters and exocytotic pathways are in addition frequent targets of microRNAs deregulated after imatinib therapy. The suitability as biomarkers for prediction of imatinib-response requires further confirmation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1097. doi:1538-7445.AM2012-1097
Abstract 1104: Nuclear translocalization of DICER correlates with high-risk clinical/histologic features in melanoma
Authors: Chakravarti Nitin , Prieto Victor , Bassett Roland
Published: August 2012

Melanoma is an aggressive malignancy with a relatively high metastatic rate, responsible for almost 60% of lethal skin tumors. Despite numerous efforts, there is still a need to better understand the molecular pathways involved in malignant melanoma metastasis. In recent years, there have been several studies highlighting the role of deregulated microRNAs (miRNAs) expression in tumor progression and metastasis. DICER is a central regulator of miRNA maturation and recently, has been shown to be upregulated in cutaneous melanoma at both protein and mRNA level. Arur et al. [1], reported DICER to be one of the ERK substrate, and this activation results in its nuclear translocalization (personal communication). However, it is unknown whether differential cellular expression of DICER contributes to the pathogenesis of melanoma. In order to test the hypothesis that aberrant nucleo-cytoplasmic expression of DICER plays a significant role in melanoma progression, we have performed semiquantitative immunohistochemical analysis of DICER in benign nevi (n=17), primary melanomas without metastasis (n=38) and with metastasis (n=27), and melanoma metastases (n=34 cases). A significant positive correlation was observed between the percentage of positive cells (p=0.003) and staining intensity (p=0.01) for nuclear DICER with progression from benign nevi to primary melanoma. Interestingly, primaries without metastasis had significantly higher levels of DICER immunopositivity in tumor cells than primaries with metastasis (p=0.02). Furthermore, metastatic melanomas showed significantly larger number of cells having intense immunoreactivity for DICER protein in nucleus than the primary melanomas (p=0.02). Significantly larger percentage of tumor cells showing DICER expression in the nucleus were observed in those lesions having ulceration (p=0.007) and vertical growth phase, which are well-established markers of poor clinical outcomes in patients with cutaneous melanoma. On the other hand, lesions showing no vascular invasion expressed higher levels of DICER in the cytoplasm (p<0.0001). Disease-specific survival was significantly shorter in patients with increased nuclear expression of DICER (p=0.04). Thus, differential cellular localization of miRNA-regulating DICER protein correlates with disease progression and high-risk clinical and histologic features in melanoma. Therefore, it will be interesting to further delineate the role of nuclear DICER in melanoma. References 1. Arur S, Ohmachi M, Nayak S, et al. Proc Natl Acad Sci U S A. 2009 Mar4;106(12):4776-81.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1104. doi:1538-7445.AM2012-1104
Abstract 1105: MicroRNAs and their targets genes promote cisplatin resistance in epithelial ovarian cancer cells
Authors: Vargas Ileabett M. Echevarria , Valiyeva Fatma , Vivas-Mejía Pablo
Published: August 2012

MicroRNAs (miRNAs) are 21-25 nucleotides regulatory involved in silencing mRNAs in a sequence specific manner. Accumulated data has established the central role of various microRNAs in tumor initiation and progression. Furthermore, recent studies revealed that microRNAs participate in the resistance of cancer cells to different chemotherapeutic agents. In ovarian carcinoma, the fifth cause of cancer deaths in US, it has been shown that several miRNAs contribute to drug resistance. However, the role of these miRNAs in the cisplatin resistance of ovarian cancer cells is unclear. In a microarray study, we found that miR-21, miR27b and miR-622 were upregulated in the A2780CP20 cisplatin resistant ovarian cancer cells compared with the A2780PAR cells, which are sensitive to cisplatin treatment. Real-time PCR studies confirmed these findings. Opposite, the c-Jun transcription factor was upregulated in this microarray analysis. Then, we used TargetScan and miRBase tools to identify miR-21, miR-27b and miR-622- target genes. Interestingly, several of these miRNA-target genes were identified as downregulated in our microarray study. These results were corroborated by Western blot analysis. Moreover, cell survival experiments in the presence of a miR-21 mimic, made A2780PAR cells more resistant to cisplatin treatment. These results indicate that dysregulation of various miRNAs and their target genes contribute to the cisplatin resistance of ovarian cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1105. doi:1538-7445.AM2012-1105
Abstract 1106: Targeting both non-coding and coding sequences with small RNA efficiently knocks down DNA repair genes and radiosensitizes human tumor cells
Authors: Zheng Zhiming , Wang Ya , Zhang Xiangming
Published: August 2012

During radiotherapy, human tumor cell death is mainly caused by ionizing radiation (IR)-induced DNA double strand breaks (DSBs). In general, human cells use two pathways: homologous recombination repair (HRR) and non-homologous end-joining (NHEJ), to repair DNA DSBs. However, in many cases, human tumors are resistant to IR due to the abnormal up-regulation of DNA DSB repair genes. Previously it was reported that using a siRNA approach could knock down the DNA DSB repair genes and sensitized the tumor cells to IR, however, the levels of knock down using a siRNA approach alone is limited. Here, we developed a novel combined approach using an artificial microRNA (amiR) to target the 3′-untranlated region (UTR) of the DNA DSB repair gene, XRCC2 (a HRR factor) or XRCC4 (a NHEJ factor), and the siRNA to target the coding region of the gene in different human tumor cell lines. Our results indicate that the combined approach is much more efficient than the amiR or siRNA approach alone in knocking down the targeted gene and sensitizing human tumor cells to IR-induced killing. The amiR decreased the targeted gene through reducing the mRNA stability and blocking the translation. These results demonstrate that the combined approach could be used for many different purposes to knock down genes in different cell lines, especially genes that are difficult to knock down using amiR or siRNA alone.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1106. doi:1538-7445.AM2012-1106
Abstract 1108: Subtype specific expression of immnune-modulating miR-155 and miR-146a in anaplastic large cell lymphoma
Authors: Merkel Olaf , Griessl Robert , Hamacher Frank , Grabner Lisa M. , Greil Richard , Kenner Lukas
Published: August 2012

Anaplastic large-cell lymphoma (ALCL) is a mature T-cell malignancy that is subdivided further into two distinct disease entities based on the presence or absence of the anaplastic lymphoma kinase (ALK) fusion protein. ALK+ ALCL bears the t(2;5) (p23;q35) translocation in greater than 80% of cases, which results in the expression of the chimeric nucleophosmin (NPM)-ALK. This leads to the activation of many different growth-promoting and anti-apoptotic pathways, including PI3K/Akt1/mTOR, Jak/Stat and AP-1. Recently, micro-RNAs (miRNAs) have emerged as tiny but potent molecules to regulate cell differentiation and proliferation. In a recent publication we have reported that miR-155 is up-regulated in ALK+ and down-regulated in ALK- ALCL. We have now identified an additional miRNA, miR-146a, that is significantly higher expressed in ALK- ALCL. Both miRNAs are strongly induced by T-cell activation. We report here that in ALCL cell lines that highly express miR-155 (like ALK- Mac1 and Mac2a) its target protein CCAAT-enhancer-binding protein ≤ (C/EBPβ) is suppressed and moreover reintroduction of miR-155 in cell lines that have low miR-155 levels (Karpas-299, SR786, SU-DHL-1, SUP-M2) can actively down-regulate C/EBPβ. Conversely, high expression of miR-146a in primary ALK- ALCL FFPE specimens corresponds to low expression of its target protein IL1 receptor-associated kinase 1 in ALK - cell lines. Due to the known roles of miR-155 and miR-146a we assessed cytokine release in a set of ALCL cell lines with and without the ALK translocation. Interestingly, we found expression of cytokines including IL-6, IL-10, IL-21 and IL-22 in ALCL cell lines. Inflammatory cytokines IL-6, IL-21 and IL-22 were 4 to 10-fold higher in ALK- cell lines, whereas anti-inflammatory IL-10 levels were not related to ALK status. Reintroduction of miR-155 into the ALK+ cell lines Karpas-299 and SR786 was able to enhance expression of IL-22. To test the influence of miR-155 on ALK- ALCL tumor growth in vivo we injected 5x10^6 Mac1 cells with low (transfected with anti-miR) or high miR-155 (transfected with pre-miR) into the flanks of BALB/c mice. High miR-155 led to a significantly enhanced tumor growth and increased IL-22 in the serum, suggesting miR-155 as tumor driver and potential therapeutic target in ALK- ALCL.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1108. doi:1538-7445.AM2012-1108
Abstract 1117: Investigating the role of PTEN-induced kinase 1 in cancer development and pathogenesis
Authors: O'Flanagan Ciara H. , Morais Vanessa , Kloos Karina , Wurst Wolfgang , de Strooper Bart , O'Neill Cora
Published: August 2012

PTEN-induced kinase 1 (PINK1) was first identified in cancer cells as a gene up-regulated by overexpression of the central tumour suppressor, PTEN. Loss-of-function mutations in PINK1 were subsequently discovered to cause autosomal recessive Parkinson's disease (ARPD). While much research has focused on the proposed mechanism(s) through which loss of PINKI function causes neurodegeneration, some studies indicate a potential role for this serine/threonine kinase in cancer cell biology. PINK1 is known to be a pro-survival kinase, protecting cells from several stressors, and is a key controller of mitochondrial integrity, morphology and function. This study aimed to understand the function of PINK1 in the development of cancer. Using SV40 immortalised PINK1 -/- mouse embryonic fibroblasts (MEFs), we show that loss of PINK1 results in reduced cell proliferation and foci formation, as well as decreased invasiveness. Overexpression of human PINK1 in these cells rescues these phenotypes and increases migratory capacity, indicating a tumour promoting role for PINK1. Furthermore, PINK1 loss increases autophagy and levels of reactive oxygen species, as well as enhancing mitochondrial fission. Notably, we identify PINK1 as a novel controller of cell cycle progression events which are critical to tumourigenesis. These results indicate an important function for PINK1 in cancer cell development.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1117. doi:1538-7445.AM2012-1117
Abstract 1119: The oxidation of proline by proline oxidase provides a regulated source of ROS for mitochondria derived cellular signaling
Authors: Hancock Chad N. , Phang James
Published: August 2012

A role for reactive oxygen species (ROS) in intracellular signaling has been generally accepted, but the organellar localization, the enzymatic source and the regulation of ROS generation are not well understood. Recent work by others has focused on mitochondria as a source of ROS and specifically on the reduction of oxygen by electrons from complex III to form superoxide. The accessibility of complex III to the mitochondrial intermembrane space and cytosol provides an attractive hypothesis for mitochondrial ROS as regulators of cellular redox signaling. We now report that the regulated metabolism of proline makes it a special substrate for this process. Proline oxidase (POX) is an inner mitochondrial membrane protein that oxidizes proline to generate superoxide as well as ATP. Work in our laboratory has documented that POX activity is highly regulated during genotoxic and metabolic stress. Inducers of POX include p53, and proline-dependent ROS play a role in mitochondrial apoptosis. PPAR-γ and its ligands also induce POX but depending on the metabolic context, POX initiates autophagy as well as apoptosis. Mechanistic models for ROS generation by POX have come from microorganisms. PutA, the prokaryotic homolog of POX can generate ROS by electrons reducing oxygen directly from its catalytic center. On the other hand, in S. cerevisiae, the POX homolog, Put1, has been shown to directly interact with ubiquinone, thereby contributing electrons derived from proline oxidation into the electron transport chain. In this work, we now report that human POX interacts directly with ubiquinone and that POX activity is markedly increased by the presence of ubiquinone. In addition, by using selective inhibitors of electron transport, we demonstrate that electrons derived from proline can be converted to superoxide by complex III of the electron transport chain. These radicals are directed into both the mitochondrial matrix as well as into the intermembrane space and the cytosol. Thus, POX is not only specifically regulated but also specially located and coupled to the mitochondrial electron transport chain to mediate ROS signaling. These POX- mediated mechanisms provide important insights into its novel apoptotic and metabolic tumor suppressive functions.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1119. doi:1538-7445.AM2012-1119
Abstract 112: An endogenous mTOR inhibitor, PRAS40, is upregulated in lung cancer and contributes to tumor cell invasion and chemoresistance
Authors: Li Zenggang , Du Yuhong , Sica Gabriel , Ramalingam Suresh S , Gal Anthony A , Pan Lin , Tighiouart Mourad Mourad , Khuri Fadlo R. Fadlo R. , Fu Haian
Published: August 2012

The proline-rich Akt substrate of 40-kDa (PRAS40) has recently been identified as a regulatory component of, TORC1 (a complex composed of mTOR, GβL, DEPTOR, RAPTOR and PRAS40)Phosphorylation of Thr246 on PRAS40 by PKB/Akt, and Ser183 and Ser221 by mTOR results in the dissociation of PRAS40 from TORC1, and binding of PRAS40 to 14-3-3 proteins. Negative mTOR regulators usually play anti-tumorigenesis roles (like TSC1-TSC2, LKB1 and PTEN). Unexpectedly, PRAS40 has been shown to acted as a pro-tumorigenic factor in certain types of cancer cells. To better understand the role of PRAS40 in cancer, we have carried out a series of cell culture and patient tumor tissue based studies. Here, we report that PRAS40 was upregulated in most of the non-small cell lung cancer (NSCLC) cell lines examined when compared to normal lung epithelial cell lines. Further immonuhistochemistry (IHC) studies confirmed the overexpression of PRAS40 in tumor tissues from NSCLC patients. Significantly, nearly 60% of cancer tissues from NSCLC patients exhibited considerably higher levels of PRAS40 protein than those in paired normal lung tissue. Such high levels of PRAS40 expression appear to be required for tumor progression as silencing of PRAS40 by shRNA decreased the cell invasion ability of NSCLC cells. Subsequently, we investigated whether PRAS40 can influence the sensitivity of NSCLC cells to chemotharepitic drugs. Our data demonstrated that downregulation of PRAS40 protein increased the sensitivity of NSCLC cells to chemotherapeutic agents, such as etopside and perifosine. In summary, our results strongly support a pro-tumorigenic role for PRAS40 and suggest PRAS40 could be a potential NSCLC therapeutic target.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 112. doi:1538-7445.AM2012-112
Abstract 1120: α-Tocopherol protects cells from lipid peroxidation and rescues tumorigenic phenotypes in CS/CSL patients with germline SDHx variants
Authors: Ni Ying , Eng Charis
Published: August 2012

Cowden syndrome (CS), a Mendelian autosomal-dominant disorder, predisposes to breast, thyroid, and other cancers. Germline mutations in phosphatase and tensin homolog (PTEN) have been found in 25% of classic CS individuals accrued from the community. Additionally, we have shown that germline variations in succinate dehydrogenase genes (SDHx) occur in 8% of 608 PTEN mutation-negative CS and CS-like (CSL) individuals (SDHvar+), compared to 0/700 controls (p<0.0001, Fisher's 2-tailed exact test). SDHx genes encode for mitochondrial complex II which lies at the crossroads of electron transport and the tricarboxylic acid cycle. We previously showed that SDHx variants result in elevated reactive oxygen species (ROS) and in disruption of such mitochondrial metabolites as flavin adenine dinucleotide (FAD) and nicotinamide adenine dinucleotide (NAD) equilibrium in CS/CSL patient-derived lymphoblastoid cells. Consequently, improper NADH quinone oxidoreductase 1 (NQO1)-p53 interaction results in destabilization of p53 and apoptosis resistance. Here we further demonstrate that elevated ROS production results in higher lipid peroxidation in SDHvar+ cells compared to healthy control cells. This increased oxidative stress led to increased mutation accumulation in mitochondrial hypervariable region II (HVRII) in samples with SDHx variants compared to controls. Interestingly, α-tocopherol treatment, but not other antioxidants, can rescue SDHvar+ cells from apoptosis resistance. This lipid soluble vitamin E, functions as a peroxyl-radical scavenger, protecting SDHvar+ cells from oxidative damage. We observed down regulated lipid peroxidation in SDHvar+ cells after α-tocopherol exposure, as well as recovered p53 expression and FAD/NAD levels. We conclude that α-tocopherol selectively protects SDHvar+ cells from redox stress and downstream tumorigenic reprogramming, which may have intriguing clinical implications such as using vitamin E as a potential preventive adjunct for CS/CSL individuals with SDHx variants.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1120. doi:1538-7445.AM2012-1120
Abstract 1121: ER-negative breast cancer survive mitochondrial IMS-stress via SIRT3 activation
Authors: Papa Luena , Shimonovoch Shahar , Germain Doris
Published: August 2012

Mitochondrial dysfunction is central in carcinogenesis and has been associated with elevated levels of Reactive Oxygen Species (ROS). While moderate levels of ROS activate signaling cascade promoting tumor progression, high levels of ROS can lead to cell death. We previously demonstrated that Estrogen Receptor (ER)-positive breast cancer cells activate ER to overcome the mitochondrial impairment and reduce high levels of ROS induced by stress in the inter-mitochondrial membrane space (IMS). The ultimate outcome of ER activation is induction of a novel Unfolded Protein Response (UPR) that involves up-regulation of NRF-1, a major regulator of mitochondrial biogenesis as well as induction of OMI and proteasome, two critical elements of protein quality control required to monitor the quality of IMS proteins. In the present work, we have evidence that ER-negative breast cancer cells trigger a distinct mechanism to cope up with IMS-stress. Due to the lack of ER, the stress from the IMS is extended into the matrix of mitochondria leading to activation of the matrix deacetylase, SIRT3. SIRT3 is required to increase the antioxidant capacity by up-regulating the antioxidant enzyme, MnSOD and therefore reducing ROS. In addition, our results reveal that SIRT3 is essential for removal of the irreversible impaired mitochondria through mitophagy. Overall, our data indicate that ER-positive and ER-negative breast cancer induce different mechanism to conquer mitochondrial malfunction coupled with ROS overproduction and maintain their cellular integrity.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1121. doi:1538-7445.AM2012-1121
Abstract 1122: Lipoic acid analogs induce ROS, leading to potent mitochondrial enzyme inhibition, metabolic dysfunction and cell death in tumor cells
Authors: Stuart Shawn D. , Zachar Zuzana , Gupta Sunita , Rodriguez Robert , Shorr Robert , Bingham Paul M.
Published: August 2012

The targeting of tumor cell metabolism has emerged as an attractive candidate for chemotherapeutics. In particular, tumor cell mitochondria are dramatically reprogrammed to generate large amounts of biosynthetic intermediates to fuel cell division. We previously described a novel class of non-redox active lipoic acid analogs (“thioctoids”) which effect dramatic inactivation of the mitochondrial enzyme complex pyruvate dehydrogenase (PDH) (PMID:21769686). We have recently completed a comprehensive metabolomic study indicating that thioctoids down-regulate multiple mitochondria-associated enzymes. Each of these target enzymes are key control points for entry of carbon into the TCA cycle, including the alpha-ketoglutarate dehydrogenase complex and the branch-chain dehydrogenase/amino trasferase complex. In addition we will present data that reactive oxygen species (ROS) play a direct regulatory role in these inactivations and are a major contributor to the resultant cell cycle arrest and multiple cell death pathways which follow. Taken together, our results indicate that thioctoids are potent inhibitors of tumor cell mitochondrial energy metabolism, owing, apparently, to the central regulatory role of lipoic acid in mitochondrial lipoamide dehydrogenase-containing enzyme complexes. We hypothesize that thioctoids are ‘misread’ by these complexes resulting in increased levels of ROS leading to the further shutdown of redox-sensitive metabolic enzymes and ultimately cell death. As a consequence of these novel properties, thioctoids attack tumor-specific metabolism far more broadly and pervasively than other agents directed at individual metabolic steps or activities. Thioctoids are exceptionally well tolerated in animal studies and as a result may have high clinical potential. They are currently in early stage human clinical trials.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1122. doi:1538-7445.AM2012-1122
Abstract 1124: Increased oxidative stress and mitochondrial dysfunction in Zucker diabetic fatty rat tissues
Authors: Raza Haider , Howarth Frank C. , John Annie
Published: August 2012

The Zucker diabetic fatty (ZDF) rat is a genetic model in which the homozygous (FA/FA) animals develop obesity and type 2 diabetes. Oxidative stress and increased expression of inflammatory signals and cytokines are the hallmarks of type 2 diabetes and cancer. Insulin signaling and IGF receptors are also affected in cancer progression. The precise molecular mechanism of disease progression or protection/prevention is, however, not clear. We, therefore, have investigated molecular and metabolic targets affected in the liver, kidney, brain and pancreas of ZDF (30 weeks old) male rats. Our results have demonstrated that GSH-dependent redox metabolism and mitochondrial respiratory function are affected in ZDF rats when compared to Zucker lean (ZL) control rats (n=6 each). With the exception of brain, cytosolic GSH content in the tissues of ZDF rats was significantly lower than ZL rats. GSH-reductase activity and GSH-conjugation by glutathione S-transferase were also lower in ZDF rat tissues. Although there was no significant increase in the apocynin sensitive- NADPH oxidase -dependent reactive oxygen species (ROS) production in the liver, DCFDA-probed ROS production and reactive nitrogen species (RNS) production were significantly higher in ZDF rat tissues. Higher levels of lipid and protein peroxidation were also observed in ZDF rat tissues. Western blot analysis also confirmed increased expression of iNOS and COX-2 suggesting an increase in oxidative stress and inflammatory markers in ZDF rat tissues. Our results have demonstrated that the increased oxidative stress in ZDF rats was accompanied by lower activities of mitochondrial respiratory complexes and decreased ATP synthesis. Taken together, our results show that ZDF rats are prone to develop complications associated with oxidative stress, inflammation and mitochondrial dysfunction as seen in the pathogenesis of cancer and diabetes. These results might have implications in designing strategies for cancer and diabetes prevention. (Supported by the Terry Fox Cancer Research Fund and a fund from FMHS Research Committee).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1124. doi:1538-7445.AM2012-1124
Abstract 1125: Consumption of oxygen: a mitochondrial-generated progression signal of advanced cancer
Authors: Cook Cody C. , Kim Ara , Terao Shuji , Gotoh Akinobu , Higuchi Masahiro
Published: August 2012

The majority of mortality from prostate cancer occurs when the disease progresses to a highly malignant phenotype. Changes in the mitochondrial genome such as mutation, deletion and depletion are common in cancer and can determine advanced phenotype of cancer; however, detailed mechanisms have not been elucidated. We observed that loss of the mitochondrial genome reversibly induced overexpression and activation of proto-oncogenic Ras, especially KRas-4A, responsible for the activation of AKT and ERK leading to advanced phenotype of prostate and breast cancer. Maturation of Ras, possibly prenylation of Ras, was required for Ras activation and was induced by the overexpression of 3- hydroxy-3-methyl-glutaryl-CoA reductase (HMGR), the rate-limiting enzyme of the mevalonate pathway. Hypoxia is known to cause accumulation of intermediate sterols which induces proteasomal degradation of HMGR. Well-differentiated and less aggressive prostate and breast cancer cells with high mitochondrial DNA (mtDNA) content consumed a large amount of oxygen and induced intracellular hypoxia. Loss of mitochondrial genome content reduced oxygen consumption and an increase in oxygen concentration (hypoxic-to-normoxic shift) in the cells. Inhibition of oxygen consumption by the reduction of mitochondrial genome content induced overexpression of HMGR through hypoxic-to-normoxic shift. Subsequently, the endogenous induction of the mevalonate pathway activated Ras that mediates advanced phenotype. Reconstitution of the mitochondrial genome or external hypoxic condition, to reverse the hypoxic-to-normoxic shift, diminished the endogenous induction of the mevalonate pathway and the activation of proto-oncogenic Ras. Reduction of mitochondrial genome content was associated with aggressive phenotype of prostate cancer in vitro cell line model and tissue specimens from prostate cancer patients in vivo. Our results elucidate a coherent mechanism that directly links the changes in mitochondrial genome with the advanced progression of the disease.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1125. doi:1538-7445.AM2012-1125
Abstract 1126: Mitochondrial DNA copy number and colorectal cancer risk: Results from the Shanghai Women's Health Study
Authors: Huang Bo , Gao Yu-Tang , Shu Xiao Ou , Wen Wanqing , Yang Gong , Li Guoliang , Ji Bu-Tian , Li Hong-Lan , Chow Wong-Ho , Zheng Wei , Cai Qiuyin
Published: August 2012

Mitochondria play an important role in cellular energy metabolism, free radical generation, and apoptosis. Cumulative evidence suggests that mtDNA copy number may be a biomarker for cancer risk. Using a nested case-control design, we evaluated mtDNA copy number in peripheral blood cells in relation to colorectal cancer risk. Included in the study were 436 colorectal cancer cases and 881 matched controls identified from the Shanghai Woman's Health Study, a population-based, prospective cohort study conducted among Chinese women. Relative mtDNA copy number was determined in triplicate by a quantitative real-time PCR assay using peripheral blood cell DNA samples collected at the time of study enrollment, prior to cancer diagnosis. Baseline levels of mtDNA copy number were lower among women who subsequently developed colorectal cancer (geometric mean = 0.271, 95% CI: 0.263-0.279) than those who remained cancer-free (geometric mean = 0.281, 95% CI: 0.275-0.288) (P=0.0274). Multivariate adjusted odds ratios were 1.15 (95% CI: 0.80-1.65), 1.12 (95% CI: 0.78-1.60) and 1.58 (95% CI: 1.10-2.26) for third to the first quartile of mtDNA copy numbers, respectively, comparing with the highest quartile (P for trend = 0.0135). The association varied little by the interval between blood draw and cancer diagnosis. To our knowledge, this is the first large prospective study evaluating the association of mtDNA copy number with subsequent risk of developing colorectal cancer. Our data suggests that decreased mtDNA copy number may be associated with increased colorectal cancer risk, and mtDNA copy number measured in peripheral blood cells may be a potential biomarker useful for colorectal cancer risk assessment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1126. doi:1538-7445.AM2012-1126
Abstract 1134: Fumarate activates NRF2 in tissues with fumarate hydratase mutation
Authors: Ooi Aikseng , Whitten Douglas , Yang Ximing J. , Zhou Ming , Richard Stéphane , Teh Bin Tean , Furge Kyle A.
Published: August 2012

Fumarate hydratase (FH) mutation is associated with hereditary type 2 papillary renal cell carcinoma. Recently, we as well as others found that nuclear factor (erythroid-derived 2)-like 2 (NRF2) activation is a dominant feature of FH mutation. We demonstrate that in hereditary type 2 papillary renal cell carcinoma, fumarate covalently modified KEAP1 and leads to its ubiquitination. Consequently, NRF2 become activated. This predicts that similar mode of NRF2 activation may also be present in other tissues with FH mutation; overexpression of NRF2 target genes in various FH mutated tissues support the prediction that NRF2 is activated in these tissues. Variation in NRF2 targets expression may account for phenotypic differences among tumors associated with FH mutation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1134. doi:1538-7445.AM2012-1134
Abstract 1136: Synergistic inhibition of bioenergetic pathways in pancreatic cancer cells by mitochondria-targeted nitroxide and glycolytic inhibitors
Authors: Cheng Gang , Zielonka Jacek , Joseph Joy , Kalyanaraman Balaraman
Published: August 2012

Pancreatic adenocarcinoma is one of the most aggressive cancers with a high fatality rate. Currently available chemotherapy for treating pancreatic cancers is ineffective. Emerging research is focused on drugs targeting bioenergetic pathways in tumor cells. Despite decades of evidence that cancer cells have increased aerobic glycolysis, glycolytic inhibition has failed as a chemotherapeutic approach, due in part to enhanced systemic toxicity of antiglycolytic agents. We hypothesized that a combined inhibition of glycolysis and mitochondrial function may represent an alternate therapeutic approach that can potentially overcome the insufficiency of glycolytic inhibition alone. In this study we investigated the chemotherapeutic efficacy of combining mitochondria-targeted nitroxide, Mito-CP (a nitroxide, carboxy proxyl conjugated to a triphenylphosphonium (TPP+) moiety), and inhibitors of glycolysis, 2-deoxy-D-glucose (2-DG) or 3-bromopyruvate (3-BP) in pancreatic cancer cell lines, PANC-1 and MiaPaCa-2. The relative cytotoxicity and mitochondrial bioenergetic changes in pancreatic cancer cells were assessed. We observed that Mito-CP synergized with glycolytic inhibitors (2-DG or 3-BP) in inducing cell death. Using a Seahorse XF24 extracellular flux analyzer, we determined the combined effects of Mito-CP and 2-DG or 3-BP on cellular mitochondrial function and glycolytic function. The combined treatments induced fast and irreversible inhibition of mitochondrial functions and intracellular ATP depletion. Collectively, these results suggest that targeting mitochondrial bioenergetic metabolism with Mito-CP and glycolytic inhibitors such as 2-DG and 3-BP may be a promising chemotherapeutic strategy in pancreatic cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1136. doi:1538-7445.AM2012-1136
Abstract 1139: Novel, cellular active inhibitors of G6PD, a key mediator of ROS-induced cellular stress
Authors: Jordan Allan M. , Hamilton Niall M. , Hamilton Nicola S. , Hitchin James R. , James Dominic I. , Jones Stuart D. , Lyons Amanda J. , March H. Nikki , Thomson Graeme J. , Waddell Ian D. , Ogilvie Donald J.
Published: August 2012

Glucose-6-phosphate dehydrogenase (G6PD) is the rate-limiting enzyme in the pentose phosphate pathway (PPP) and catalyses the oxidation of glucose-6-phosphate to glucono-δ-lactone-6-phosphate with the concomitant production of NADPH. Alongside an important role in the production of biosynthetic precursors such as ribonucleotides, this pathway is a major cellular source of NADPH. As such, the pathway plays a critical role in both the biosynthesis of fatty acids & cholesterol biosynthesis (thus supporting cell division) and maintaining glutathione in its reduced state (GSH), the latter ameliorating cellular stress arising from reactive oxygen species (ROS). Given these key roles, modulation of the pathway has potential therapeutic application, and inhibition of G6PD is an attractive target, particularly in combination with standard of care radiotherapy or cytotoxic drugs which can increase ROS. We have developed a series of novel steroid G6PD inhibitors which, in our hands, modulate flux through the PPP and increase ROS-induced stress in cells. This disclosure will describe some of our results in this area.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1139. doi:1538-7445.AM2012-1139