bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract LB-466: Genomic Loss of microRNA 491 contributes to IGFBP2 overexpression and stemness in GBM
Authors: Li Xia , Liu Yuexin , Ji Ping , Chua Yingxuan , Hu Limei , Guo Fei , Sun Yan , Lang Frederick , Zhang Wei
Published: August 2012

Insulin-like growth factor-binding protein 2 (IGFBP2) is overexpressed in 80% of glioblastoma multiforme (GBM, WHO grade IV). Our mouse model experiments demonstrated that IGFBP2 is a glioma oncogene. However, the underlying mechanism for overexpression of IGFBP2 remains unknown. We examined a total of 388 GBM samples from the Cancer Genome Atlas (TCGA) and found that miR-491, which is located on chr9p21.3, is deleted in 57% of cases. TargetScan analysis revealed that there is a binding site of miR-491 on the 3′-UTR of the IGFBP2 gene. The miR-491 expression levels in GBM patients are inversely correlated with that of IGFBP2. We validated this regulatory relationship by overexpression of miR-491 and observed down-regulation of IGFBP-2 in both protein level and mRNA level in U251 and T98G glioma cell lines. Conversely, miR-491 inhibitors increased IGFBP2 in LN229 cells which express low level of endogenous IGFBP2. Luciferase reporter assay further proved that IGFBP2 is a direct target of miR-491. Moreover, ectopic expression of miR-491 inhibited cell migration and invasion of U251 and T98G as efficiently as knockdown of IGFBP2 and such inhibitory effects can be partially reversed by overexpression of IGFBP2-EGFP in U251, supporting the notion that IGFBP2 plays an important role in miR-491's functions. To investigate the role of miR-491 in stemness of GBM, we introduced miR-491 into 3 patient-derived glioma stem cell lines and found that miR-49 downregulated CDK6 and Bcl-xL and inhibited neurosphere formation and cell proliferation. These findings suggest that miR-491 acts as a tumor suppressor miR by coordinately attenuating multiple oncogenes in GBM. Our results provide new insights into the mechanism for oncogenic IGFBP2 overexpression and may provide new opportunities for therapeutic strategies for GBM treatment.

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 LB-466. doi:1538-7445.AM2012-LB-466
Abstract LB-482: MiRNA replacement therapy in vivo: antitumor effects of nanoparticle-formulated miR-145 and miR-33a, and targeting of Pim-1
Authors: Weirauch Ulrike , Ibrahim Ahmed Fawzy , Thomas Maren , Lange-Grünweller Kerstin , Grünweller Arnold , Hartmann Roland K. , Aigner Achim M.
Published: August 2012

Various miRNAs are aberrantly expressed in cancer. In colon carcinoma, decreased levels of the pro-apoptotic and anti-proliferative miRNA-145 are observed, while the role of miR-33a has not been analysed yet. In this study, we demonstrate the tumor-inhibitory role of miR-33a and newly identify the proto-oncogenic kinase Pim-1 as its direct target. Comparably to siRNA-mediated knockdown of Pim-1, miR-33a reduces Pim-1 expression and thus inhibits proliferation in leukemia and in colon carcinoma cells by decelerating cell cycle progression. Most recent in vitro and in vivo data from our group further establish the so far unknown functional relevance of Pim-1 in colon carcinoma and identify Pim-1 as attractive target gene. Among others, RNAi-mediated Pim-1 knockdown reduces tumor growth, induces apoptosis and leads to major changes in oncogenic signal transduction, including the inhibition of STAT3. The therapeutic application of miRNAs strongly relies on the development of suitable delivery tools, and we introduce polyethylenimine (PEI)-based nanoparticles for systemic or local miRNA administration in vivo. PEIs mediate miRNA protection, delivery to target organs, cellular uptake and intracellular release. MiRNA replacement therapy through systemic or local injection of PEI/miR-145 complexes results in efficient miRNA delivery and in antitumor effects in s.c. colon carcinoma xenograft mouse models. Likewise, tumor growth inhibition is observed upon treatment with PEI-complexed miR-33a. This is due to the miR-33a-mediated downregulation of Pim-1 expression, comparable with the Pim-1 knockdown through PEI/siRNA complexes. Conclusions: (i) The PEI-complexation of miRNAs represents a novel strategy in miRNA replacement therapy, (ii) miR-145 / miR-33a may be promising candidate miRNAs, and (iii) Pim-1 is a newly identified, attractive target gene in colon carcinoma.

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 LB-482. doi:1538-7445.AM2012-LB-482
Abstract LB-496: Low-dose aspirin targets tumor-associated inflammation and delays neuroblastoma tumor growth in vivo
Authors: Carlson Lena-Maria , Rasmuson Agnes , Segerstrom Lova , Sveinbjornsson Baldur , Kogner Per
Published: August 2012

ABSTRACT Tumor-associated inflammation is a driving force in several adult cancers, and low doses of non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin have proven to reduce cancer incidence. Little is known about tumor-associated inflammation in pediatric neoplasms and no in vivo data exists on the effectiveness of low-dose aspirin on established tumors. Our study evaluates inflammatory patterns paralleling neuroblastoma (NB) tumor growth in vivo and low-dose aspirin as a therapeutic option for high-risk NB. Using the TH-MYCN mouse model of NB, this study demonstrates the presence and progression of tumor-associated inflammation during NB tumor growth. Ex vivo analysis of tumors revealed a transition from an adaptive immune response predominated by CD8+ T-cells in neoplastic lesions from 5 week old homozygous mice, towards an enrichment in immature cells of the innate immune system, including myeloid-derived suppressor cells (MDSCs), immature dendritic cells (DCs) and M2 tumor-associated macrophages (TAMs) during tumor progression. An ongoing M1 to M2 transition of TAMs was demonstrated, which was paralleled by a gradual deterioration of DC status. Ten days of consecutive anti-inflammatory treatment with low-dose aspirin significantly reduced tumor burden (p<0.01) and the presence of tumor-associated cells of the innate immune system (p<0.01) in homozygous mice. In conclusion, our study depicts how inflammatory pathways assist tumor progression through sculpturing of the tumor microenvironment, and for the first time demonstrates an in vivo effect of low-dose aspirin on established MYCN amplified NB tumors in a transgenic mouse model, suggesting a potential new treatment option for high-risk NB patients.

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 LB-496. doi:1538-7445.AM2012-LB-496
Abstract LB-502: Development of three dimensional cancer cell-CAF co-culture system
Authors: Arai Kazuya , Sakamoto Ruriko , Itoh M , Miura Haifeng
Published: August 2012

Purpose A large number of cell lines have been established and used for cancer research. Monolayer culture of cancer cells alone is a simplified and effective method, however, it does not always reflect the physiological conditions. In this study, we tried to establish a simple co-culture method of cancer cells and CAF (cancer associated fibroblast), to develop three dimensional model of stroma rich tumor with cells such as pancreatic cancer and scirrhous cancer. Method Human tumor tissue samples were obtained from patients who had undergone surgery at the National Cancer Center Hospital East, Japan. Written informed consents were obtained from all patients. BxPC-3 (pancreatic cancer cell line) and A549 (lung cancer cell line) were stained with red-fluorescent dye, PKH-26. Pancreatic cancer derived- and lung cancer derived-CAF were stained with green-fluorescent dye, PKH-67. Cancer cells and CAF are seeded into the microtiter plates for 3D cell culture (NanoCulture® Plate) at a same cell number, and spheroid formation was measured by a fluorescent time lapse microscopy for 3-days. Result BxPC-3 (red) and Pancreatic CAF (green) merged well and formed mosaic spheroids. BxPC-3 (red) and lung CAF (green) did not merge and separately formed spheroids of each cell types. A549 and lung CAF merged, but A549 and Pancreatic CAF did not merge clearly. It is suggested that a specific recognition mechanisms exist by organ types or tumor types, with the adhesion between cancer cell and CAF. A) BxPC-3 and Pancreatic CAF B) BxPC-3 and lung CAF Conclusion In this study, mosaic spheroid were formed by co-culturing of same organ derived cancer cells and CAF. This co-culture system is expected as an effective tool for cancer microenvironment study and/or drug screening targeting with stroma rich tumor.

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 LB-502. doi:1538-7445.AM2012-LB-502
Abstract LB-509: Early detection of pancreatic cancer in transgenic mice with ultrasonic molecular imaging and VEGFR2-targeted microbubbles
Authors: Pysz Marybeth A. , Seeley Elliot S. , Foygel Kira , Gambhir Sanjiv S. , Tian Lu , Brentnall Teresa A. , Willmann Juergen K.
Published: August 2012

Pancreatic cancer is a lethal disease largely due to presence of advanced and inoperable disease at the time of diagnosis. Evidence from current screening programs for high-risk individuals suggests that aggressive detection at operable stages could dramatically improve prognosis; however, current radiological imaging screen methods are not standardized and rely on solid mass recognition from anatomical/morphological imaging strategies. Incorporation of a molecular imaging strategy can provide a highly reliable and cancer-specific diagnosis, as well as, improved delineation of tumor boundaries for therapeutic and surgical guidance. Molecular ultrasound imaging is accomplished by conjugating targeting molecules (peptides/antibodies) to the surface of gas-filled microbubble contrast agents (1-4 μm diameter), and these contrast agents bind to markers overexpressed on disease-associated endothelium. In this study, we investigated the ability to detect small pancreatic cancers with contrast microbubbles targeted to vascular endothelial growth factor receptor type 2 (VEGFR2) and small animal transabdominal ultrasound (US) imaging in a transgenic mouse model of pancreatic cancer (Pdx1-Cre; KRasV12G; Ink4a-/-; PC mice). Small tumors ranging from 0.8 mm to 3.0 mm in diameter (mean: 1.7 ± 0.6 mm) could be detected with high-resolution B-mode US imaging, and showed 7.8-fold higher (P < 0.001) VEGFR2-targeted molecular US signal (mean signal intensity: 6.5 ± 8.4 arbitrary units; n=32 tumors) in PC mice compared with normal pancreas in wildtype mice (mean signal intensity: 0.8 ± 0.6 arbitrary units; n=14 mice). Small pancreatic tumors showed 3-fold higher VEGFR2-targeted US signal (mean signal intensity: 10.5 ± 9.4 arbitrary units) compared with US signal measured with non-targeted microbubbles (mean signal intensity: 3.6 ± 1.8 arbitrary units), indicating high specificity for VEGFR2. Ex vivo histological (H&E) analysis and immunostaining of VEGFR2 confirmed millimeter-sized tumors in the pancreas and VEGFR2 expression in PC mice (VEGFR2-positive tumors); in contrast, pancreas tissue from normal, wildtype mice was VEGFR2-negative. Taken together, these studies indicate that VEGFR2-targeted US imaging can detect small pancreatic cancers that are not normally recognized with conventional anatomical imaging, and may be highly useful for establishing a standardized pancreatic cancer screening/monitoring method for high-risk patients. Supported by the Canary Foundation, and NIH/NCI grants R21 CA139279 and Fellowship R25 CA11868.

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 LB-509. doi:1538-7445.AM2012-LB-509
Abstract LB-513: Abelson Interactor 1 is a novel substrate of protein kinase D2: potential implications in tumor cell migration
Authors: Nimmagadda Subbaiah Chary , Eiseler Tim , Lint Johan Van , Storz Peter , Seufferlein Thomas
Published: August 2012

Introduction and Objective: The serine/threonine kinases of the protein kinase D family (PKCmu/PKD1, PKD2, PKCnu/PKD3), a subfamily of the CAMK superfamily, have been implicated in regulation of multiple biological processes including proliferation, survival, apoptosis, angiogenesis and motility. The precise mechanisms by which the three PKDs modulate these processes are incompletely understood and require a better knowledge of their signaling context. Methodology and Results: Using the ProtoArray Human Protein Microarray v4.0 (Invitrogen), we identified Abelson interactor 1 (ABI1) as a novel PKD2 substrate. ABI1 was first identified as the downstream target of Abl tyrosine kinase and is an adaptor protein involved in actin reorganization and lamellipodia formation along with WAVE2. In the present study we illustrate that PKD2 interacts and phosphorylates ABI1 in vitro and in vivo at two potential serine residues. The sites were validated using an antibody that specifically identifies the consensus PKD substrate sequence. Furthermore, PKD2-induced phosphorylation of ABI1 destabilized the interaction between ABI1 and WAVE2 and resulted in relocation of both the proteins from plasma membrane to perinuclear region. Consequences of this destabilization and its potential impact on WAVE2 driven actin polymerization and the associated processes are in the process of investigation. Preliminary results also suggest reduced migration velocity and directedness of a tumor cell. Conclusion: In conclusion, our data demonstrate that ABI1 is a novel substrate of PKD2 that might negatively regulate tumor cell migration via terminating a constitutive interaction between ABI1 and WAVE2. *Impact of ABI1-WAVE2 subcomplex destabilization on WAVE2 induced actin polymerization and lamellipodia extension will be presented at the meeting.

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 LB-513. doi:1538-7445.AM2012-LB-513
Abstract LB-518: Amplification and activation of EGFR wild-type mediates invasion of human glioblastoma in vivo
Authors: Talasila Krishna M. , Soentgerath Anke , Euskirchen Philipp , Rosland Gro V. , Wang Jian , Huszthy Peter C. , Prestegarden Lars , Skaftnesmo Kai Ove , Sakariassen Per Øystein , Eskilsson Eskil , Keunen Olivier , Brekka Narve , Moen Ingrid , Nigro Janice , Vintermyr Olav , Lund-Johansen Morten , Mørk Sverrre J. , Enger Per Øyvind , Bjerkvig Rolf , Miletic Hrvoje
Published: August 2012

Glioblastoma (GBM) is the most aggressive form of primary brain tumors with a median survival of 15 months. Although angiogenesis is one of the main features of GBMs, non-angiogenic tumor infiltration into brain parenchyma still is the major challenge for therapy. Tumor cells can migrate very far from the main tumor mass and the invasive pattern of tumor subpopulations has not been characterized properly. Epidermal growth factor receptor (EGFR) gene amplification is one of the major mutations of primary GBMs, where multiple copies of the wild-type EGFR gene are present as double minutes. Although studies have proposed a role for EGFR gene amplification in tumor development, the function of EGFR in vivo is not characterized properly mainly due to inefficient tumor models. Here, we report a key role for EGFR wild-type in tumor invasion. In a human GBM xenograft model, we show that tumor cells with EGFR amplification and expression are highly invasive and non-angiogenic. By blocking EGFR activation using Cetuximab and a dominant-negative approach, we show that maintenance of the non-angiogenic, invasive growth pattern is dependent on EGFR function and that downregulation of its activity leads to angiogenic tumor growth. As EGFR amplification and expression is present in 40-60% of GBMs, our results might implicate that activation of EGFR wild-type is one of the major mechanisms of glioblastoma invasion in vivo.

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 LB-518. doi:1538-7445.AM2012-LB-518
Abstract LB-54: The foundation for melanoma research
Authors: Beston Richard
Published: August 2012

The Foundation for Melanoma Research was founded in 1999 by Noreen O'Neill, a prominent Philadelphia businessperson. Noreen, who was diagnosed with malignant melanoma in 1995 and lost her battle to the disease in 2000. She looked to volunteer with organizations dedicated to advancing treatments for melanoma patients. Finding none, she decided to build one herself. The organization is dedicated to raising awareness about melanoma and funding research into increased prevention, early detection, and new treatments, with the eventual goal of finding a cure. All funds raised go to melanoma research scientists at The Wistar Institute, a world-reknowned biomedical research organization at the University of Pennsylvania in Philadelphia. Wistar continues to be on the cutting-edge of melanoma discoveries towards a cure. The Noreen O'Neill Foundation for Melanoma Research is dedicated to raising awareness about melanoma and funding research into increased prevention, early detection, and new treatments. Annual intiatives include Running for Cover 5k walk/run, Date With a Plate, the annual Wallace Clark Lectures, and a close tie with Philadelphia professional sports teams.

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 LB-54. doi:1538-7445.AM2012-LB-54
Abstract LB-67: COX-2/PGE2: molecular ambassadors of Kaposi's sarcoma associated herpes virus (KSHV) oncoprotein-v-FLIP
Authors: Sharma-Walia Neelam , Patel Kinjan , Chandran Karthic , Marginean Alexandru , Bottero Virginie , Kerur Nagaraj , George-Paul Arun
Published: August 2012

Kaposi's sarcoma herpesvirus latent oncoprotein viral FLICE-like inhibitory protein (v-FLIP) or K13, a potent activator of NF-κB has well established roles in KSHV latency and oncogenesis. KSHV induced COX-2 represents a novel strategy employed by KSHV to promote latency and inflammation/angiogenesis/invasion. Here, we demonstrate that v-FLIP/K13 promotes tumorigenic effects via induction of host protein COX-2 and its inflammatory metabolite PGE2 in an NF-κB dependent manner. In addition to our previous studies demonstrating COX-2/PGE2's role in transcriptional regulation of KSHV latency promoter and latent gene expression, current study adds to the complexity that though LANA-1 (latency associated nuclear antigen) is utilizing COX-2/PGE2 as critical factors for its transcriptional regulation, it is the v-FLIP/K13 gene in the KSHV latency cluster that maintains continuous COX-2/PGE2 levels in infected cells. We demonstrate that COX-2 inhibition, via its chemical inhibitors (NS-398 or celecoxib), reduced v-FLIP/K13 mediated NF-κB induction, and extracellular matrix (ECM) interaction mediated FAK/Src/AKT, Rac-1 activation, mitochondrial antioxidant enzyme manganese superoxide dismutase (MnSOD) levels, and subsequently down-regulated detachment-induced apoptosis (anoikis) resistance. COX-2 inhibition in v-FLIP/K13-Human microvascular endothelial cells (HMVECs) reduced inflammation and invasion/metastasis related genes along with reduced anchorage independent colony formation via modulating ‘extrinsic’ as well as ‘intrinsic’ cell death pathways. COX-2 blockade in v-FLIP/K13-HMVECs drastically augmented cell death induced by removal of essential growth/survival factors secreted in the microenvironment. Transformed cells obtained from anchorage independent colonies of COX-2 inhibitor treated v-FLIP/K13-HMVEC cells expressed lowered levels of endothelial mesenchymal transition (EndMT) genes such as slug, snail and twist, and higher expression of the tumor suppressor gene E-cadherin. Taken together, our study provides strong evidences that FDA approved COX-2 inhibitors have great implications in blocking tumorigenic events linked to KSHV's oncogenic protein v-FLIP/K13.

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 LB-67. doi:1538-7445.AM2012-LB-67
Abstract LB-68: Mouse mammary tumor virus suppress apoptosis through Src signaling in the mammary epithelial cells
Authors: Kim Hyoung H.
Published: August 2012

Many receptors in the hematopoietic immune cells use common signaling pathway that relies on immunoreceptor tyrosine-based activation motif (ITAM). ITAMs are highly conserved sequence. Signal transduction by these motifs is mediated by Src family tyrosine kinases including Lyn, Fyn, Lck. ITAM bearing proteins are found in many oncogenic viruses and associated with transformation and tumorigenesis in epithelial and endothelial cells. These proteins include Epstein Barr Virus LMP2A, Kaposi's sarcoma virus K1, and bovine leukemia virus gp30. MMTV envelope protein is another viral ITAM bearing protein implicated in mammary tumor development. We previously have shown that MMTV envelope protein expression transform mouse mammary epithelial cells and Src kinases are important mediators in this transformation. To study how ITAM signaling affects transformation and progression of mammary tumor we developed mammary cell lines that express MMTV provirus and have a mutated ITAM counterpart. Using PCR based expression profiling we found that MMTV-ITAM turns on the embryonic transcription factors and induce epithelial-mesenchymal transition which is important in malignant tumor progression. Many genes related to cell adhesion and invasion was changed. Anti-apoptotic regulator bcl-2 level was significantly increased. Importantly MMTV expressing cells became resistant to apoptosis induced by serum starvation. Cells transduced with ITAM mutated MMTV were indistinguishable from wild type cells. We also found Src kinase, a downstream signal transducer of ITAM signaling is activated in the MMTV expressing cells, and MMTV induced apoptosis resistance was completely restored by Src inhibitor PP2. Our results show that MMTV suppress apoptosis through ITAM mediated Src tyrosin kinase signaling. The studies in signaling pathways and apoptosis resistance induced by ITAM containing proteins in nonhematopoietic cells could lead to the development of effective treatment of cancers in which ITAM-mediated signaling plays a role.

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 LB-68. doi:1538-7445.AM2012-LB-68
Abstract SY10-01: Uncovering the cellular origin of skin cancers
Authors: Blanpain Cedric
Published: August 2012

Stem cells (SCs) are responsible for tissue homeostasis and repair. SCs have been hypothesized to be the cells at the origin of cancer. However, for the vast majority of cancers, the cell at the origin of tumor initiation is still unknown. Two epithelial skin cancers are frequent in human populations: the basal cell carcinoma (BCC) and the squamous cell carcinoma (SCC).

We developed new genetic approaches to identify the cells at the origin of BCC and SCC in mice. Using mice conditionally expressing constitutively active Smoothened mutant (SmoM2) or KRas mutant (G12D), we activated hedgehog or Ras signaling in different cellular compartments of the skin epidermis, and determined from which epidermal compartments oncogene expression induces cancer formation. Using clonal analysis, we found that SmoM2 induced BCC arise from long-term resident progenitor cells of the interfollicular epidermis. In contrast, expression of mutant KRas in hair follicle bulge stem cells (SCs), but not in their transient amplifying progeny, led to benign squamous skin tumor (papilloma). Whereas no malignant tumor was observed following KRasG12D expression alone, expression of KRasG12D combined with the loss of p53 induced invasive SCC formation (3). Our studies uncover the cells at the origin of SmoM2 induced BCC and and Kras induced SCC in mice and demonstrate that expression of differentiation markers in tumor cells is not necessary predictive of the cancer initiating cells.

We have now developed novel strategy to isolate by flow cytometry oncogene targeted cells at different time following oncogene expression and determined the molecular changes associated with tumor initiation and malignant progression. The functional relevance of these genes is currently investigated using gain and loss of function in mice. These new results and the relevance of these findings to human skin cancers will be presented.

Acknowledgement This work is supported by Welbio, the FNRS, the program d'excellence CIBLES of the Wallonia Region, Fondation Contre le Cancer, the European Research Council (ERC) and the EMBO Young Investigator Program.

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 SY10-01. doi:1538-7445.AM2012-SY10-01
Abstract SY11-02: Microenvironment matters: TGFβ regulates the response to DNA damage
Authors: Barcellos-Hoff Mary Helen
Published: August 2012

Transforming growth factor β1 (TGFβ) is a central regulator of the microenvironment in both normal tissues and tumors. TGFβ resides in the extracellular matrix as a latent complex that requires activation prior to binding to ubiquitous cell surface receptors to initiate a signaling cascade culminating in nuclear Smad activation of transcription. Most cancer cells are no longer responsive to TGFβ growth suppression, yet maintain a partially intact signaling pathway. Why?

Surprisingly, we found that either Tgfb1 genetic deletion in mouse cells or TGFβ inhibition in human cells compromises the execution of the molecular cascade in response to DNA damage. Irradiated epithelial cells exhibit decreased ATM kinase activity and autophosphorylation, reduced phosphorylation of critical DNA damage transducers, and abrogation of cell cycle blockade and apoptosis, which together result in increased radiosensitivity. The ability of exogenous TGFβ to restore these responses indicates that the effect is both cell intrinsic and distal to TGFβ signaling. Recent studies suggest that TGFβ regulates multiple components of the DNA damage response, supporting the conclusion that extrinsic TGFβ is necessary for efficient execution of the intrinsic DNA damage response.

TGFβ may thus provide a survival advantage in tumors, which are a source of exuberant TGFβ activity, provides an unexpected avenue for in cancer treatment. Both ionizing radiation and chemotherapy actually elicit TGFβ activity via redox- and integrin-mediated activation. We tested the translational potential of the requirement for TGFβ in the genotoxic stress program during radiotherapy using TGFβ neutralizing antibodies and small molecule inhibitors of the TGFβ type I receptor kinase in experimental models of breast, lung and brain cancer in vivo and in vitro. TGFβ inhibition prior to radiation increased the radiosensitivity of 10 of 12 human cancer cell lines as measured by clonogenic assay and decreased γH2AX phosphorylation. Notably, glioma stem cells were preferentially protected from DNA damage by high levels of TGFβ, which also promoted self-renewal, both of which were compromised by TGFβ inhibition. Administration of TGFβ neutralizing antibody in vivo increased tumor growth delay following single or multiple radiation fractions and also reduced metastasis. We anticipate that use of TGFβ inhibitors in the context of radiotherapy will increase radiosensitivity and impair the protective tumor microenvironment, providing both local and systemic benefit.

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 SY11-02. doi:1538-7445.AM2012-SY11-02
Abstract SY13-01: Reporter imaging in cancer biology and therapy
Authors: Piwnica-Worms David
Published: August 2012

The tools of molecular imaging can provide spatially- and temporally-resolved information on biological structures and functions. Because researchers have increasingly recognized the importance of context for understanding gene expression and protein function as well as regulatory mechanisms within cellular micro-environments, they have turned to non-invasive imaging technologies to advance research on human health and disease. These non-invasive imaging data can interrogate protein processing, protein-protein interactions, gene expression and flux through metabolic pathways in real-time in cells and live animals, and are increasingly useful in understanding signal transduction and the pathobiology of cancer, which can facilitate development of effective therapies.

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 SY13-01. doi:1538-7445.AM2012-SY13-01
Abstract SY20-02: Role of Polycomb repressors in stem cells, cancer, DNA repair and iPS cell reprogramming
Authors: van Lohuizen Maarten
Published: August 2012

Repressive Polycomb-group (Pc-G) protein complexes and the counteracting Trithorax-group (Trx-G) of nucleosome remodeling factors are involved in the dynamic maintenance of proper gene expression patterns during development, acting at the level of chromatin structure. As such, they are important controllers of cell fate. When deregulated, these master switches of gene expression are strongly implicated in formation of a diverse set of cancers, including leukemia, breast cancer, prostate cancer and glioblastoma. To identify critical Polycomb targets and pathways implicated in brain cancer we performed comprehensive Bmi1-ChIP-seq profiling of mouse and human glioma ‘stem-like’ cells followed by in vivo shRNAi-library screening. These studies revealed a critical cross-talk between the BMP/TGFβ signaling pathways and Bmi1 and also provided new candidate tumor suppressors and non-coding RNAs associated with gliomagenesis. Furthermore, we have characterized in detail an essential E3-ubiquitin ligase activity in the PRC1 Polycomb complex that consists of a functional Ring1B-Bmi1 heterodimer. This E3 ligase activity is required for maintenance of Polycomb repression in normal- and cancer stem cells and hence offers potential novel ways to target cancer stem cells or tumor reforming cells in which the activity of this E3 ligase is hyperactivated. This is further substantiated by dynamic regulation of the Ring1B.Bmi1 E3 ligase activity which also has implications for a novel link between Polycomb silencing and control of Double-Strand DNA repair. Lastly, our recent studies revealed an unanticipated important role for Polycomb repression in the process of cellular ‘iPS’ cell reprogramming. The implications of these findings for stem cell biology, development, and possibilities for new translational approaches to cancer will be discussed.

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 SY20-02. doi:1538-7445.AM2012-SY20-02
Abstract SY21-02: DNA methylation and epigenetic instability in human cancer
Authors: Feinberg Andrew P.
Published: August 2012

Alterations in DNA methylation in human cancer were identified 30 years ago but a comprehensive view has emerged with the advent of whole genome bisulfite sequencing. While cancer can be viewed as over 200 distinct diseases that are organ-specific in their pathology, and mutation-specific in their molecular mechanism, recent discoveries in cancer epigenetics suggest a different but complementary view. Epigenetically, cancer may approach a single disorder with certain common features underlying the major reasons for cancer morbidity and mortality. Specifically, several common solid tumor types show increased epigenetic instability in DNA methylation at specific loci but involving the same loci in many different tumor types, and these loci appear to be critical for unregulated cell growth and tissue invasion and metastasis, and they involve the boundaries between CpG islands and shores, as well as large hypomethylated genomic blocks. These blocks correspond to large organized chromatin lysine (K) -modified domains (LOCKs) that are normally modulated during cellular reprogramming in development and epithelial-mesenchymal transition. We suggest a unifying model for the epigenetic basis of cancer in which increased instability in gene expression is mediated by loss in cancer of nuclear structures that control variance during normal development, such as LOCKs and CpG island boundaries. By this view, stochastic noise is a necessary part of cell fate determination leading to Waddingtonian canalization, and cancer is a disease, at least epigenetically, in which these canals are shallower, with increasing noise and the probability of cell type transitions that should not appear in differentiated tissues. At the same time, this increased noise increases the fitness of cancer cells and their resistance to any given 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 SY21-02. doi:1538-7445.AM2012-SY21-02
Abstract SY29-02: The TSC-mTOR pathway and control of anabolic tumor cell metabolism
Authors: Manning Brendan D.
Published: August 2012

The mammalian target of rapamycin (mTOR) complex 1 (mTORC1) plays an evolutionarily conserved role as a molecular link between cellular growth conditions and the anabolic processes promoting cell growth. This protein kinase complex has the ability to sense and integrate signals emanating from pathways that monitor cellular growth conditions, including the availability of intracellular nutrients and energy, the presence of specific growth factors and cytokines, and a variety of cellular stresses. Importantly, the integrated control over mTORC1 activity and cell growth is corrupted in most human tumors. mTORC1 senses many of these upstream signals through a small G protein switch involving the tuberous sclerosis complex (TSC) tumor suppressors, TSC1 and TSC2, and the Ras-related small G protein Rheb, an essential activator of mTORC1. The TSC1-TSC2 complex functions as a GTPase-activating protein (GAP) for Rheb, thereby stimulating its conversion to the inactive GDP-bound form and inhibiting its activation of mTORC1. Multi-site phosphorylation of the TSC1-TSC2 complex downstream of distinct signaling pathways accounts for much of the signal-integrating capacity of mTORC1. Importantly, both the oncogenic PI3K-Akt and Ras-Erk pathways phosphorylate and inhibit TSC2 to activate mTORC1. Aberrant regulation of the TSC1-TSC2 complex leading to constitutive activation of mTORC1 is a common molecular event in a large variety of pathological settings, including the majority of genetic tumor syndromes and sporadic cancers. However, the molecular mechanisms by which the TSC1-TSC2 complex is regulated and functions to properly control Rheb and mTORC1 are not well understood. Furthermore, the downstream consequences of dysregulated mTORC1 signaling in tumors remain poorly defined. This lecture will focus on recent studies in our laboratory to 1) characterize a third stoichiometric component of the TSC1-TSC2 complex and its role in mTOR regulation, and 2) the role of mTORC1 in the metabolic reprogramming of tumor cells induced by common oncogenic events.

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 SY29-02. doi:1538-7445.AM2012-SY29-02
Real-Time Monitoring of the Effects of Telmisartan on Angiotensin II-Induced Mechanical Changes in Live Mesangial Cells Using Atomic Force Microscopy
Authors: Jeong Kyung-Hwan , Lee Tae-Won , Ihm Chun-Gyoo , Moon Joo-Young , Lee Gi-Ja , Park Hun-Kuk , Lee Sang-Ho
Published: August 2012

Background/Aims: Recent studies have shown that angiotensin II (Ang II) type 1 receptor blockers (ARB) may provide renal protection independent of their blood pressure-lowering effect. However, evidence for this comes from indirect methods, such as genetic or protein expression studies. In this study, we hypothesized that telmisartan, a specific ARB, applied to Ang II-stimulated mesangial cell (MC) would exert a renoprotective effect via modulation of MCs’ mechanical properties. Methods: We investigated the effect of telmisartan on Ang II-induced changes in MCs utilizing real-time atomic force microscopy (AFM) imaging and force-distance curve measurements. Results: Real-time AFM images of live MCs demonstrated that cells contracted towards the center after Ang II exposure, and telmisartan treatment abolished this change. Cellular spring constants showed that telmisartan prevented Ang II-induced MC stiffening (Ang II: 0.109 ± 0.019 N/m, Ang II + telmisartan: 0.051 ± 0.016 N/m, p < 0.005). Telmisartan-treated MCs had a significantly lower adhesion force than those of the control group (control: 0.49 ± 0.22 nN, telmisartan: 0.22 ± 0.06 nN, Ang II: 0.40 ± 0.25nN, Ang II + telmisartan: 0.27 ± 0.14 nN, p < 0.005). These results demonstrate that the dynamic contraction and mechanical properties of Ang II-stimulated MCs are restored by telmisartan. Conclusions: We report for the first time the use of AFM force-distance curves on live MCs to directly monitor changes in surface adhesion and stiffness of cells after treatment with telmisartan in real time.
Differential Distribution of CYP2A6 and CYP2A13 in the Human Respiratory Tract
Authors: Chiang Huai-chih , Wang Chien-Kai , Tsou Tsui-Chun
Published: August 2012

Background: Human CYP2A6 and CYP2A13 play important roles in metabolic activation of many pulmonary carcinogens and thus their expression and distribution may determine the pulmonary susceptibility to metabolically activated carcinogens and the following lung cancer development. Because of the 93.5% of amino acid identity between CYP2A6 and CYP2A13, generation of antibodies specific to CYP2A6 or CYP2A13 has limited immunohistochemical (IHC) analysis of CYP2A6 and CYP2A13 levels in the respiratory tract. Objectives: This study aimed to determine the differential distribution of CYP2A6 and CYP2A13 in human respiratory tissue with IHC analysis. Methods: With computer-aided protein sequence analyses, candidate epitopes of 15 amino acids in the C-terminal domains of CYP2A6 and CYP2A13 were selected for antibody generation. Specificity of these two antibodies was confirmed with immunoblot and immunofluorescence analyses. With these two selective antibodies, the differential distribution of CYP2A6 and CYP2A13 in human respiratory tissues, including tracheae, bronchi, bronchioles and alveoli, was determined. Results: IHC results showed that both CYP2A6 and CYP2A13 were markedly expressed in epithelial cells of tracheae and bronchi and that only CYP2A6 was detected in bronchiolar epithelial cells of peripheral lungs. A limitation of the present study is the cross-reactivity of our CYP2A6 antibody to the functional inactive CYP2A7. Conclusions: The differential distribution patterns of CYP2A6 and CYP2A13 in the respiratory tract are of importance in considering the pulmonary susceptibility to carcinogens and the following lung cancer development.
Pulmonary Disease Caused by Rapidly Growing Mycobacteria: A Retrospective Study of 44 Cases in Japan
Authors: Yano Yukihiro , Kitada Seigo , Mori Masahide , Kagami Shinichi , Taguri Takahiro , Uenami Takeshi , Namba Yoshinobu , Yoneda Tsutomu , Yokota Soichiro , Maekura Ryoji
Published: August 2012

Background: The features of pulmonary disease caused by rapidly growing mycobacteria (RGM) have not been sufficiently documented. Objectives: To establish these features, we retrospectively evaluated 44 patients. Methods: We screened respiratory isolates at the National Toneyama Hospital (Osaka, Japan) between 2003 and 2007. Diagnosis was based on the latest guidelines of the American Thoracic Society. The patients were classified into 3 types according to their radiographic findings: fibrocavitary, nodular bronchiectatic and unclassified variant. Results: We obtained 1,348 nontuberculous mycobacteria respiratory isolates from 1,187 patients, including 119 RGM isolates from 100 patients. Forty-four of these 100 patients were definitively diagnosed with respiratory disease due to RGM. The most common pathogen was Mycobacteriumabscessus, which accounted for 65.9% of cases, followed by Mycobacterium fortuitum at 20.5%. There was a statistically significant difference in smoking history between patients infected with these 4 RGM species (excluding those with an unknown smoking history; p = 0.039). The overall evaluation of radiographic findings revealed 18.2% as fibrocavitary, 43.2% as nodular bronchiectatic and 38.6% as unclassified variants in these 44 patients. There was a significant difference in radiographic findings between the 4 RGM species (p = 0.002). There was also a significant difference in radiographic findings between M. abscessus and M. fortuitum infected patients (p = 0.022). Conclusions: Patients with M. abscessus seem to have less of a smoking history and more frequent nodular bronchiectatic radiographic patterns than patients with M. fortuitum. In contrast, fibrocavitary patterns might be more frequent with M. fortuitum infection.
Inflammation-Based Prognostic Score Predicts Survival in Patients with Advanced Gastric Cancer Receiving Biweekly Docetaxel and S-1 Combination Chemotherapy
Authors: Kunisaki Chikara , Takahashi Masazumi , Ono Hidetaka A. , Oshima Takashi , Takagawa Ryo , Kimura Jun , Kosaka Takashi , Makino Hirochika , Akiyama Hirotoshi , Endo Itaru
Published: August 2012

Objectives: This study was conducted to determine the prognostic value of the Glasgow Prognostic Score (GPS), an inflammation-based prognostic score composed of C-reactive protein and albumin, for patients with advanced cancer. Methods: A total of 83 advanced gastric cancer patients receiving biweekly docetaxel/S-1 treatment (DS) were included in the study. To identify the value of GPS as prognostic factor for disease-specific survival (DSS) and progression-free survival (PFS), univariate and multivariate analyses were performed. Results: Unresectable tumors were observed in 78 patients and recurrent tumors were detected in 5 patients. Of these, 12 patients underwent gastrectomy. There were significant correlations between the GPS and the neutrophil/lymphocyte ratio. Univariate analysis revealed that the GPS, Eastern Cooperative Oncology Group performance status and gastrectomy after DS treatment significantly affected prognosis. Multivariate analysis showed that the GPS, age and gastrectomy independently influenced DSS, and that the GPS and gastrectomy also influenced PFS. Multivariate analysis restricted to patients without gastrectomy showed that the GPS and age independently affected DSS, and that the GPS influenced PFS. Conclusion: In the low GPS group, it may be possible to obtain favorable outcomes by chemotherapy in advanced gastric cancer patients. However, a well-designed prospective trial in a large patient cohort is required to corroborate the prognostic value of the GPS.
Increasing Time to Baccalaureate Degree in the United States
Authors: Bound John , Lovenheim Michael F. , Turner Sarah
Published: August 2012

Time to completion of the baccalaureate degree has increased markedly in the United States over the past three decades. Using data from the National Longitudinal Survey of the High School Class of 1972 and the National Educational Longitudinal Study of 1988, we show that the increase in time to degree is localized among those who begin their postsecondary education at public colleges outside the most selective universities. We consider several potential explanations for these trends. First, we show that changes in the college preparedness and the demographic composition of degree recipients cannot account for the observed increases. Instead, our results identify declines in collegiate resources in the less selective public sector and increases in student employment as potential explanations for the observed increases in time to degree.
Who Comes Back? A Longitudinal Analysis of the Reentry Behavior of Exiting Teachers
Authors: Grissom Jason A. , Reininger Michelle
Published: August 2012

While a large literature examines the factors that lead teachers to leave teaching, few studies have examined what factors affect teachers’ decisions to reenter the profession. Drawing on research on the role of family characteristics in predicting teacher work behavior, we examine predictors of reentry. We employ survival analysis of time to reentry for exiting teachers using longitudinal data from the 1979 National Longitudinal Surveys of Youth. We find that younger, better paid, and more experienced teachers are more likely to reenter. We also find that women are more likely to return to teaching than men. Child rearing plays an important role in this difference. Women are less likely to reenter with young children at home. We conclude that reentrants may be an important source of teacher labor supply and that policies focused on the needs of teachers with young children may be effective ways for districts to attract returning teachers.