bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1087: Differential oncogenicity of N-RAS mutations in melanoma.
Authors: Burd Christin , Jeck William R. , Fu Kailing , Clark Kelly S. , Xiong Jessie C. , Souroullas George P. , Sharpless Norman E.
Published: August 2014

In human cancer, N-RAS mutations resulting in constitutive, oncogenic signaling are predominately localized to codons 12, 13 or 61. Traditionally, activating RAS mutations have been considered oncogenically equivalent, yet recent studies suggest important clinical distinctions between colon cancers containing K-RAS codon 12 vs. codon 13 mutations. More than 20% of human melanomas harbor N-RAS mutations, the vast majority of which target codon 61, as opposed to N-RAS mutations of codon 12 or 13, which are common in other tumor types. To address this issue, we characterized syngeneic knock-in mouse models conditionally expressing either N-RasG12D or N-RasQ61R under the control of the endogenous locus. In primary melanocyte cultures, activation of either N-Ras allele reduced cellular proliferation even in the presence of concomitant p16INK4a deletion. Correspondingly, melanocyte-specific N-RasG12D expression combined with p16INK4a loss failed to efficiently promote melanoma formation in mice. In contrast, melanocyte-specific N-RasQ61R induction readily combined with p16INK4a loss to promote melanoma formation in vivo with short latency and high penetrance. These results provide a first murine model of melanoma featuring knock-in N-Ras mutationQ61R, and suggest that the preference for codon 61 mutations in human tumors is conserved in mice.

Citation Format: Christin Burd, William R. Jeck, Kailing Fu, Kelly S. Clark, Jessie C. Xiong, George P. Souroullas, Norman E. Sharpless. Differential oncogenicity of N-RAS mutations in melanoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1087. doi:10.1158/1538-7445.AM2013-1087
Abstract 1089: Spontaneous formation of sarcomas in Usp18 knockout mice.
Authors: Chinyengetere Fadzai , Giustini Andrew , Sekula David , Freemantle Sarah , Memoli Vincent A. , Hoopes Paul Jack , Dmitrovsky Ethan
Published: August 2014

Undifferentiated pleomorphic sarcoma (UPS) and leimyosarcoma are two of the most common adult soft tissue sarcomas. Their etiology is unknown hence the need for new models to elucidate the biology of these diseases. We report here a spontaneously occurring mouse model of sarcoma in Usp18 knockout mice. Usp18 is the deconjugase for isgylation. Isgylation is the ubiquitin-like protein modification in which ISG15 is conjugated to proteins. Usp18 removes ISG15 from the target proteins, thus reversing the functional consequences of ISG15 conjugation. Usp18 knockout mice on a C57Bl6 background developed neurological abnormalities and exhibited 100% mortality within 5 months. These mice were also hypersensitive to Type I IFN stimulation, which was attributed to an increased JAK-STAT signaling. We now report that Usp18 knockout mice in a FVB background developed subcutaneous tumors in the neck and trunk regions from ages ranging from 6 months to 16 months. Tumor formation to date shows a penetrance of 77%. Immunohistochemical analysis characterized the tumors as either UPSs or leimyosarcomas. About 30% of these tumors displayed stabilization of p53, a common event also seen in human sarcomas. We derived two cell lines (KHC-1, KHC-2) from the sarcomas of separate mice, and analyzed the levels of STAT family proteins in these cell lines. Stat3 was noted to be constitutively activated in these sarcoma cell lines. Persistent activation of Stat3 is seen in diverse human malignancies such as breast and head and neck cancers. To determine if restoring Usp18 activity reverses tumorigenicity in these cells, human USP18 was introduced retrovirally. Cells re-expressing USP18 versus empty vector showed a substantial decrease in anchorage independent growth in soft agar and also had reduced levels of activated Stat3 (pStat3). Furthermore, treatment of the parental cell lines with a Stat3 inhibitor, JSI-124, led to decreased cell growth, apoptosis and reduced levels of pStat3. In summary, Usp18 knockout mice spontaneously develop sarcomas, whose tumorigenicity can be partially reversed by reintroduction of Usp18. Thus, this new and tractable model should prove useful to elucidate the activity of Stat3 targeting and other agents to treat sarcomas.

Citation Format: Fadzai Chinyengetere, Andrew Giustini, David Sekula, Sarah Freemantle, Vincent A. Memoli, Paul Jack Hoopes, Ethan Dmitrovsky. Spontaneous formation of sarcomas in Usp18 knockout mice. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1089. doi:10.1158/1538-7445.AM2013-1089
Abstract 1090: NR2F1 coordinates a dormancy program by inducing low self-renewal capacity and a repressive chromatin state.
Authors: Sosa Maria S. , Estrada Yeriel , Parikh Falguni , Gutierrez Almudena Bosch , Zheng Yang , Bragado Paloma , Ekpin Esther , George Ajish , Farias Eduardo , Aguirre-ghiso Julio
Published: August 2014

Clinical studies have shown that solitary disseminated tumor cells (DTCs) in distant organs can be detected years after treatment of primary tumors. This has led to the notion that these solitary DTCs must enter a non-proliferative state or cellular dormancy. This may also hold true for residual tumor cells left behind in loco-regional sites after surgery. Unfortunately, the mechanisms regulating the timing of dormancy and the awakening of DTCs to fuel recurrences are unknown. Similarly, tools to stably induce dormancy of residual disease are unavailable. Here we show that transient differentiation signals propagated by treatment (3-4 days) with retinoic acid (atRA) along with the DNA demethylating agent 5-Aza-C reprogrammed malignant cells into dormancy for remarkably long periods of time (weeks). This reprogramming was associated with upregulation of the orphan nuclear receptor NR2F1/COUP-TF1 and other genes included in a gene signature previously linked to dormancy and late metastasis in breast patients. Importantly, the reprogramming was dependent on NR2F1, which is also silenced in breast and HNSCC tumors, cell lines and mouse cancer models. NR2F1-induced dormancy was associated with a global repressive chromatin state characterized by a H3K27-/K9-me3high/H3K4-me3/H3K27aclow profile. In both breast and HNSCC models NR2F1 blocked self-renewal extinguishing tumor initiating cell subpopulations. Tracking label retaining H2B-GFP cells, gain and loss of function studies showed that NR2F1-induced quiescence occurs via upregulation of SOX9, RARβ and CDK inhibitors. Importantly, inducible shRNAmir-mediated knock down of NR2F1 revealed that it mediates dormancy of occult loco-regional, spleen and lung DTCs, but not of dormant bone marrow DTCs. We conclude that the ability of NR2F1 to limit self-renewal and promote quiescence is key to dormancy induction. Manipulation of such mechanisms via epigenetic and differentiation therapies might represent a strategy to generate induced dormant cancer cells (iDCs) and maintain or eliminate asymptomatic residual disease.

Citation Format: Maria S. Sosa, Yeriel Estrada, Falguni Parikh, Almudena Bosch Gutierrez, Yang Zheng, Paloma Bragado, Esther Ekpin, Ajish George, Eduardo Farias, Julio Aguirre-ghiso. NR2F1 coordinates a dormancy program by inducing low self-renewal capacity and a repressive chromatin state. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1090. doi:10.1158/1538-7445.AM2013-1090
Abstract 1097: Transient mechanical stimulation can enhance cancer cell invasion.
Authors: Orzakar Snehal , Beningo Karen A.
Published: August 2014

Formation of secondary tumors by metastasis is a leading cause of death in cancer patients. During metastasis cells separate from the primary tumor, invade the stroma, travel through blood and lymph and colonize tissues distant from the primary mass. Several biochemical factors have been identified which are able to drive this metastatic cascade. However information of the role of mechanical factors in cancer metastasis has primarily focused on the effect of compliance, overshadowing other mechanical factors that might facilitate the metastatic progression. For example, contractile cells produce short term stress on extracellular matrix fibers during extensive remodeling of the stroma, such variable and transient force would easily propagate through the fibers providing communication between cells. To simulate this type of stress, we developed an in vitro invasion assay where cancer cells are subjected to tugging or pulling forces, similar in randomness and magnitudes to those produced by contractile cells in the tumor microenvironment, without interference of any secreted factors that could be provided by the stromal cells. We discovered a significant difference in the extent of invasion by cancer cells that were mechanically stimulated in this manner verses non- stimulated cell culture environments. This response requires the presence of fibronectin in the extracellular matrix. The objective of our current study is to understand the mechanotransduction pathway leading to enhanced invasion. We speculated that in response to mechanical forces in the stroma, tumor cells will show an altered expression of genes involved in mechanosensing. We performed expression profiling of several genes related to cell migration, adhesion and tumor metastasis by real-time PCR analysis. Given a 24 hour assay period, six genes were confirmed to be differentially expressed between mechanically stimulated and non-stimulated conditions. Of particular interest was the down-regulation of a fibronectin specific integrin subunit in response to the mechanical stimulation that enhanced invasion. Over-expression of this gene resulted in a significant decrease in enhanced invasion, supporting its role in sensing the mechanical stimulus. We speculate that mechanical stimulation during cancer cell invasion results in integrin cross-talk leading to the downregulation of specific integrins, while enriching others within the invadopodia.

Citation Format: Snehal Orzakar, Karen A. Beningo. Transient mechanical stimulation can enhance cancer cell invasion. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1097. doi:10.1158/1538-7445.AM2013-1097
Abstract 1098: Mechano-molecular imaging of the role of COX-2 in cell traction force.
Authors: Yoon A Rum , Stasinopoulos Ioannis , An Steven , Bhujwalla Zaver M.
Published: August 2014

The cytoplasmic enzyme cyclooxygenase (COX)-2 and its secondary lipid byproducts are critical determinants of cancer cell invasion and metastasis. Poorly differentiated MDA-MB-231 human breast cancer cells stably expressing COX-2 shRNA exhibit marked attenuation in their ability to secrete secondary lipid mediator products of the COX reaction, as well as invade and degrade reconstituted extracellular matrix in vitro. COX-2-silenced cells inoculated in vivo show significant reduction of tumor growth and extrapulmonary colonization than their parental counterpart. Based on compelling evidence for the positive correlation between cancer invasion and cell traction force, here we interrogated the mechanistic role for COX-2 in mediating this physical force and imaged the spatiotemporal distribution of contractile stress arising at the interface between each adherent cell and its substrate. Over a physiological range of substrate stiffness, COX-2-silenced MDA-MB-231 cells exhibited a smaller spreading area and a lower cell traction force than their highly metastatic, parental counterpart. Strikingly, unlike COX-2-silenced cells, COX-2-high parental MDA-MB-231 cells showed progressive increases in cell spreading area and traction force with increasing substrate rigidity. Cell spreading and traction force in COX-2-silenced cells were restored with an exogenous addition of COX-2-derived PGE2, however. COX-2-high MDA-MB-231 cells also showed increases in the expression of mechanosensitive integrin β1, and not β3, with increasing substrate rigidity. Consistent with these physical attributes, COX-2-silenced cells expressed a 4.6-fold reduction of the transcript coding for RhoJ, a member of the family of Rho GTPases, and displayed a slower remodeling dynamics of the cytoskeleton (CSK). To our knowledge this is the first report linking the expression of COX-2 with increased cell traction force and CSK remodeling in a highly metastatic human breast cancer.

Citation Format: A Rum Yoon, Ioannis Stasinopoulos, Steven An, Zaver M. Bhujwalla. Mechano-molecular imaging of the role of COX-2 in cell traction force. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1098. doi:10.1158/1538-7445.AM2013-1098
Abstract 1100: Dynamic multicellular mechanics controlling protrusion in 3D.
Authors: Fessenden Timothy , Gardel Margaret L.
Published: August 2014

Despite much effort, the transition from benign to malignant breast cancer remains poorly understood, resulting in overtreatment of women with in situ lesions. A growing appreciation for the role of cell mechanics in driving cell behavior has prompted interest in how mechanical interactions might control tumor growth and progression. How these parameters impact the transition from benign to malignant breast cancer remains unclear.

Mechanical interactions among cells via adherens junctions, and between cells and the ECM via focal adhesions, can each exert dominant effects on cell behavior. Cell motility and invasion require force interactions by harnessing cytoskeletal dynamics, which permit shape changes and generate and transmit forces. Tension maintained across the actin cortex mechanically restricts protrusions, and may be transmitted across multiple cells via adherens junctions. Thus epithelial cells form mechanically integrated tissues that may be responsive to changes in cortical tension over great distances. However, the regulatory role of cortical tension in restricting cells from protruding is unclear. Overall, we lack detailed morphologic and mechanical models of cell protrusion and invasion out of 3D collectives.

Using MDCK cell exposure to HGF as a model for rupture of epithelial integrity and protrusion, we have demonstrated the morphologic parameters that permit protrusion of a cell from its surrounding epithelium. Combined with work from our lab on force interactions between cells via adherens junctions, as well as mechanical interactions between a cell and its substrate, we may extrapolate detailed force interactions that underlie the observed cell shape and motility parameters that permit protrusion.

Citation Format: Timothy Fessenden, Margaret L. Gardel. Dynamic multicellular mechanics controlling protrusion in 3D. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1100. doi:10.1158/1538-7445.AM2013-1100
Abstract 1101: Examining the role of the mechanical microenvironment in pancreatic cancer: microrheology studies in 3D tumor models.
Authors: Celli Jonathan P. , Rizvi Imran , Jones Dustin , Hanna William , Hasan Tayyaba
Published: August 2014

A growing body of literature points to the importance of the mechanical microenvironment, including rheology (rigidity, viscoelastic properties) of the surrounding extracellular matrix (ECM), as a regulator tumor growth behavior. This is particularly provocative for tumors of the pancreas, which are noted for profound desomplasia characterized by exceptionally dense, collagen-rich, hypovascular, fibrous stroma. While this property of pancreatic tumor stroma has been implicated in drug resistance, and even explored as a therapeutic target (stromal depletion), key questions about the role of the mechanical microenvironment remain unanswered. For example, it is unclear the extent to which this extreme matrix rigidity is driven by the tumorigenic program or what its role is in contributing to the notorious treatment-resistance of these tumors, beyond serving as a physical barrier to drug penetration. In this study we leverage in vitro 3D pancreatic tumor-fibroblast co-culture models combined with particle tracking microrheolgy as a tool to longitudinally probe the mechanical properties of the surrounding ECM during growth and in response to exogenous stimuli. Cultures are prepared by embedding pancreatic cancer cells (PANC-1, AsPC-1 or Capan-1) along with normal human fibroblasts (MRC-5) and (biologically-inert) fluorescent tracer probes in a collagen matrix. The Brownian motion of tracer probes obtained by high-speed digital video microscopy and subsequent offline particle tracking analysis, is used as a reporter of spatio-temporal changes in the viscoelastic properties of ECM. This, combined with our previously introduced high-content quantitative imaging approach for assessment of growth and treatment response in 3D tumor models comprises a platform for mapping of interdependent changes in the matrix mechanics and tumor growth behavior. In this study we correlate changes in matrix stiffness under normal growth, with and without stromal fibroblasts present as signaling partners and TGF-β stimulation. We further explore local mechanical effects by comparing groupings of trajectories of probes proximal and distant from tumor nodules. In ongoing studies we are examining the impact of traditional chemotherapeutics and photodynamic therapy (PDT) on modulation of the mechanical microenvironment and conversely, the impact of ECM rigidity on treatment sensitivity.

Citation Format: Jonathan P. Celli, Imran Rizvi, Dustin Jones, William Hanna, Tayyaba Hasan. Examining the role of the mechanical microenvironment in pancreatic cancer: microrheology studies in 3D tumor models. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1101. doi:10.1158/1538-7445.AM2013-1101
Abstract 1106: Mechanism for activation of mutated EGF receptors in lung cancer.
Authors: Red Brewer Monica L. , Lai Darson , Lemmon Mark A. , Pao William
Published: August 2014

Previous studies have demonstrated that wild-type (WT) EGFRs are activated by an allosteric mechanism in which a ‘donor’ tyrosine kinase domain (TKD) monomer contacts an ‘acceptor’ TKD monomer, leading to its activation. Here, we present biochemical reconstitution data demonstrating that receptor activation by the most frequently occurring EGFR mutations found in lung cancer does not adhere to this mechanism. Mutated EGFRs hyperphosphorylate their WT counterparts and appear to adopt a conformation that allows them to function as acceptors but not as donors to WT EGFR. As acceptors, the mutated EGFRs also show enhanced association with WT EGFR. We suggest the term “superacceptor activity” to describe this directionally-limited mutant-specific mechanism of EGFR transactivation. Mutated EGFRs also hyperphosphorylate the related ErbB family member, ErbB-2, in a similar manner. Collectively, these data provide insights into a mechanism for activation of lung cancer-associated mutant EGFRs. Since WT EGFRs are usually present in EGFR mutant tumor cells, our studies additionally argue that WT EGFRs contribute to tumorigenesis and may alter sensitivity to EGFR-targeted therapy.

Citation Format: Monica L. Red Brewer, Darson Lai, Mark A. Lemmon, William Pao. Mechanism for activation of mutated EGF receptors in lung cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1106. doi:10.1158/1538-7445.AM2013-1106
Abstract 1116: Sleeping Beauty mutagenesis identifies genes and pathways that cooperate with BrafV600E in melanoma initiation and progression.
Authors: Mann Michael B. , Black Michael A. , Ward Jerrold M. , Bosenberg Marcus W. , McMahon Martin , Print Cristin G. , Adams David J. , Copeland Neal G. , Jenkins Nancy A.
Published: August 2014

Malignant melanoma is a devastating disease the prevalence of which is on the rise. In humans, somatic mutation of BRAF, to encode the BRAFV600E oncoprotein, is an early predisposing event in melanoma initiation, but is insufficient to drive malignant melanomagenesis in the absence of additional cooperating events. We describe a genome-wide, forward genetic screen in mice restricted to pigment producing melanocytes as an unbiased approach to identify new candidate melanoma progression genes. By combining Sleeping Beauty (SB) with a Cre-activated BRafCA allele we observed frank melanomas with average latency of 36 weeks. By contrast, melanocyte specific expression of BRAFV600E elicited benign melanocytic nevi that failed to progress to malignant melanoma by one year of age. These findings confirm that SB mobilization altered genes that cooperate with BRAFV600E to promote melanoma progression. A discovery set of 1,200 statistically-defined candidate melanoma genes was identified from 70 SB|BRAFV600E tumors. Importantly, our screen identified seven SB mutated genes with human orthologs that are well established human melanoma drivers including: Cdkn2a, Pten, Gnaq, Mitf, Nf1, Rac1 and Ppp6c. Many biological signaling pathways and cellular processes were enriched for candidate melanoma genes altered in SB|BRAFV600E melanomas, including Wnt/Beta-catenin, TGFβ, PI3’-kinase and MAPK signaling pathways and biological processes regulating ubiquitin mediated proteolysis, tight junctions, cell cycle and axonal guidance. Integrated comparative oncogenomic analysis with human melanoma data sets provided a data-driven method to filter and prioritize candidate melanoma genes. The genes identified using the SB|BRAFV600E model may represent new human melanoma candidate cancer genes with potential clinical relevance to the progression and maintenance of human BRAF mutated melanoma.

Citation Format: Michael B. Mann, Michael A. Black, Jerrold M. Ward, Marcus W. Bosenberg, Martin McMahon, Cristin G. Print, David J. Adams, Neal G. Copeland, Nancy A. Jenkins. Sleeping Beauty mutagenesis identifies genes and pathways that cooperate with BrafV600E in melanoma initiation and progression. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1116. doi:10.1158/1538-7445.AM2013-1116
Abstract 1126: Efficacy of BET bromodomain inhibition in Kras-positive non-small cell lung cancer.
Authors: Shimamura Takeshi , Chen Zhao , Soucheray Margaret , Carretero Julian , Kikuchi Eiki , Tchaicha Jeremy H. , Gao Yandhi , Cheng Katherine A. , Cohoon Travis J. , Qi Jun , Akbay Esra A. , Kimmelman Alec C. , Kung Andrew L. , Bradner James E. , Wong Kwok Kin
Published: August 2014

Amplification of MYC is one of the most common genetic alterations in lung cancer, contributing to a myriad of phenotypes associated with growth, invasion and drug resistance. Murine genetics has established both the centrality of somatic alterations of Kras in lung cancer, as well as dependency of Kras-dependent tumors on c-Myc function. Unfortunately, drug-like small-molecule inhibitors of KRAS and c-Myc have yet to be realized. The recent discovery in hematologic malignancies that bromodomain inhibition impairs MYC expression and MYC-dependent transcriptional function prompted the possibility of targeting KRAS-driven NSCLC with a potent, prototypical BET bromodomain inhibitor, JQ1. Here, we report that NSCLC cells harboring the KRAS mutation are sensitive to JQ1 while NSCLC cells with concurrent mutant KRAS and LKB1 mutations are resistant to JQ1. In sensitive NSCLC models, JQ1 treatment results in the coordinate downregulation of the MYC-dependent transcriptional program. Furthermore, we evaluated JQ1 in transgenic mouse lung cancer models expressing mutant kras or concurrent mutant kras and lkb1. We found that JQ1 treatment produces significant tumor regression in mutant kras mice. As predicted, tumors from mutant kras and lkb1 mice did not respond to JQ1. Together, these data provide a compelling rationale for the study of BET bromodomain inhibitors in a common, genetically-defined population of patients with aggressive NSCLC.

Citation Format: Takeshi Shimamura, Zhao Chen, Margaret Soucheray, Julian Carretero, Eiki Kikuchi, Jeremy H. Tchaicha, Yandhi Gao, Katherine A. Cheng, Travis J. Cohoon, Jun Qi, Esra A. Akbay, Alec C. Kimmelman, Andrew L. Kung, James E. Bradner, Kwok Kin Wong. Efficacy of BET bromodomain inhibition in Kras-positive non-small cell lung cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1126. doi:10.1158/1538-7445.AM2013-1126
Abstract 1130: Antitumor activity of a pyrrole-imidazole polyamide in three tumor xenograft models.
Authors: Nickols Nicholas G. , Yang Fei , Li Benjamin C. , Marinov Georgi K. , Said Jonathan W. , Dervan Peter B.
Published: August 2014

Background: Pyrrole-imidazole polyamides are synthetic minor groove binders with modular sequence recognition. We developed a polyamide that targets the DNA sequence 5’-WGWWCW-3’ (W=A/T). This molecule is cytotoxic in a number of cancer cell lines including LNCaP (prostate cancer), DU145 (prostate cancer), and A549 (lung cancer). Data in cell culture suggests that this molecule interferes with RNA polymerase 2 activity resulting in proteasome-mediated degradation of the RNA Polymerase 2 large subunit, activation of p53 and induction of p53 target genes, and apoptosis. This polyamide demonstrates no detectable DNA damage by alkaline comet assay nor does it induce detectable phosphorylation of γH2A.X, ATM, DNA-PKcs, p53, or Chk2. This polyamide circulates in mice after intravenous and subcutaneous injection in saline vehicle.

Methods: Male immune compromised mice were implanted with LNCaP, DU145, or A549 tumors. Tumors were allowed to grow until approximately 100 mm3 and then stratified into vehicle (5% DMSO/PBS) and treatment arms (1 mg/kg polyamide, in vehicle). Treatment was administered via subcutaneous injection every three days, for a total of three cycles (LNCaP), eight cycles (DU145), or six cycles (A549). At the experimental endpoint, tumors were resected and weighed immediately. For LNCaP xenografts, serum PSA pre- and post-treatment were also measured. In parallel, a group of immune compromised mice without xenografts were treated with an identical regimen for eight cycles and subsequently observed for three months.

Results: Tumors resected from polyamide-treated mice were statistically smaller than those of vehicle-treated mice. The effect was greatest on LNCaP tumors (n=12, Treated (T)/Control (C): 32%, p=1.6E-5). DU145 tumors (n=6, T/C: 34%, p=0.013), and A549 tumors (n=8, T/C: 62%, p=0.047) were also affected. Post-treatment serum PSA in the polyamide-treated mice with LNCaP xenografts were lower than for the vehicle treated mice (p = 0.024). Statistical differences between treated and control groups were determined using two-tailed t-tests. Polyamide treatment resulted in no significant weight loss or observable distress in tumor-free mice and these mice appeared healthy for at least three months after treatment was complete.

Conclusions: The polyamide demonstrated in vivo antitumor activity in this panel of tumor xenografts with limited host toxicity.

Citation Format: Nicholas G. Nickols, Fei Yang, Benjamin C. Li, Georgi K. Marinov, Jonathan W. Said, Peter B. Dervan. Antitumor activity of a pyrrole-imidazole polyamide in three tumor xenograft models. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1130. doi:10.1158/1538-7445.AM2013-1130
Abstract 1133: Synthetic lethal screen identifies candidates that modulate cancer cell sensitivity in response to HSP90 inhibition.
Authors: Howes Jennifer , Lu Bing-Feng , Powers Marissa , Clarke Paul , Workman Paul
Published: August 2014

Heat shock protein 90 (HSP90) is an important cancer therapeutic target. HSP90 chaperone activity maintains the conformation, stability and function of mutated variants and over-expressed oncogenic client proteins responsible for driving the proliferation of human cancer. To further increase the efficacy and specificity of HSP90 inhibitor treatment, cancer cell response to HSP90 inhibition can be modulated through the use of combinatorial therapeutics. An siRNA screen targeting 7,593 genes encoding proteins considered to be druggable was used to identify candidates that modulate the cellular response to HSP90 inhibition by 17-AAG. This approach may provide information on the potential mechanisms of cancer cell resistance, allow selection of responsive patient populations based on the identification of novel biomarkers, and potentially provide targets for combinatorial therapy. Screening produced robust data with an average plate z-factor of 0.6 and results were validated with an alternative chemotype of HSP90 inhibitor. As anticipated, significant sensitisation to HSP90 inhibition was observed with HSF1 depletion, and conversely resistance was observed with NQO1 depletion. Sensitisation candidates were the main focus of analysis as they potentially represent the more amenable drug targets. There was an enrichment of mitochondrial constituents, cell cycle regulators and post-translational protein modifiers that when depleted produced significant sensitisation to HSP90 inhibitors in human carcinoma cells. Future work aims to reveal the molecular mechanisms underpinning the sensitisation phenotypes observed and to identify points of intervention for clinical combinatorial therapy with HSP90 inhibitors.

Citation Format: Jennifer Howes, Bing-Feng Lu, Marissa Powers, Paul Clarke, Paul Workman. Synthetic lethal screen identifies candidates that modulate cancer cell sensitivity in response to HSP90 inhibition. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1133. doi:10.1158/1538-7445.AM2013-1133
Abstract 1137: Expression of specific apoptotic mediators predicts sensitivity to combined MEK and PI3K inhibition in KRAS mutant non-small cell lung cancer according to TP53 mutational status.
Authors: Hata Aaron , Faber Anthony , Yeo Alan , Chen Zhao , Wong Kwok-Kin , Engelman Jeffrey
Published: August 2014

Non-small cell lung cancer (NSCLC) is the leading cause of cancer death world-wide. Though targeted therapies have been developed for NSCLC with activating EGFR mutations or the EML4-ALK translocation, no highly effective targeted therapies exist for cancers harboring activating KRAS mutations. We previously observed that concomitant use of MEK and PI3K inhibitors (MEKi/PI3Ki) led to tumor regressions in a mouse model of KRAS mutant NSCLC, and clinical trials investigating this strategy are underway. However, KRAS mutant NSCLCs are a heterogeneous group of cancers, and the molecular determinants of sensitivity to MEKi/PI3Ki are unknown. Here we report that human KRAS mutant NSCLC cell lines exhibit variability in responsiveness to MEKi/PI3Ki resulting from differential apoptotic responses. We identified key pro- and anti-apoptotic regulators regulators of the apoptotic response induced by MEKi/PI3Ki. Loss of the apoptotic response due to down-regulation of pro-apoptotic mediators was associated with acquired resistance to MEKi/PI3Ki. The responsiveness of KRAS mutant NSCLCs to combined MEKi/PI3Ki could be predicted by the relative expression levels of specific apoptotic regulators, depending on TP53 mutational status. These results reveal genotype-specific mechanisms of apoptosis necessary for responsiveness to targeted therapies and suggest biomarkers for predicting responsiveness of KRAS mutant NSCLC to MEKi/PI3Ki.

Citation Format: Aaron Hata, Anthony Faber, Alan Yeo, Zhao Chen, Kwok-Kin Wong, Jeffrey Engelman. Expression of specific apoptotic mediators predicts sensitivity to combined MEK and PI3K inhibition in KRAS mutant non-small cell lung cancer according to TP53 mutational status. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1137. doi:10.1158/1538-7445.AM2013-1137
Abstract 1140: Novel single-nucleotide polymorphism markers predictive of pathologic response to preoperative chemoradiotherapy in rectal cancer patients.
Authors: Kim Jin Cheon , Roh Seon Ae , Cho Dong Hyung , Choi Eun Young , Ha Ye Jin , Kim Tae Won , Kim Jong Hoon , Kang Tae Wook , Kim Seon Young , Kim Yong Sung
Published: August 2014

Purpose: Studies aimed at predicting individual responsiveness to preoperative chemoradiotherapy (CRT) are urgently needed, especially considering the risks associated with poorly responsive patients, i.e., delay of curative surgery, immune suppression, and adverse effects.

Methods and Materials: A three-step strategy for the determination of CRT sensitivity is proposed that includes: 1) screening of a human genome-wide single-nucleotide polymorphism (SNP) array correlated with histopathological tumor regression grade (TRG), 2) clinical association analysis in 113 patients treated with preoperative CRT, and 3) a cell-based functional assay for biological validation. Genome-wide screening identified nine SNPs associated with preoperative CRT responses.

Results: Genome-wide screening identified nine SNPs associated with preoperative CRT responses. The patients carrying the reference allele (C) of the SNP CORO2A rs1985859 exhibited greater positive responses (TRG 1-3) than those with the substitution allele (T) (P=0.01). Down-regulation of CORO2A was associated with significantly reduced early apoptosis in RKO and COLO320DM colorectal cancer cells by 27% (P=0.048) and 39% (P=0.023), respectively, as determined by flow cytometry. Although a specific genotype associated with radiosensitivity was not detected in the clinical association analysis, down-regulation of FAM101A significantly increased the viability of RKO and COLO320DM cells by 25% (P=0.01) and 23% (P=0.023), respectively in the MTT assay. Conclusion: CRT-sensitive SNP markers were identified using a novel three-step process. The candidate marker CORO2A rs1985859 and the putative marker FAM101A rs7955740 may improve the prediction of radiosensitivity to preoperative CRT, although further validation is needed in large cohorts.

Citation Format: Jin Cheon Kim, Seon Ae Roh, Dong Hyung Cho, Eun Young Choi, Ye Jin Ha, Tae Won Kim, Jong Hoon Kim, Tae Wook Kang, Seon Young Kim, Yong Sung Kim. Novel single-nucleotide polymorphism markers predictive of pathologic response to preoperative chemoradiotherapy in rectal cancer patients. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1140. doi:10.1158/1538-7445.AM2013-1140
Abstract 1152: Identification of protein tyrosine kinase 7 gene in hepatocellular carcinoma using a novel triple-combination array analysis.
Authors: Hishida Mitsuhiro , Nomoto Shuji , Inokawa Yoshikuni , Hayashi Masamichi , Yamada Suguru , Fujii Tsutomu , Sugimoto Hiroyuki , Takeda Shin , Kodera Yasuhiro
Published: August 2014

Background. Hepatocellular carcinoma (HCC) is one of the top five causes of cancer-related deaths worldwide. Recent developments in the treatment of HCC still have failed to prevent HCC. Genome-wide gene-expression profile analyses can now detect many candidate genes that are modified by HCC. We have developed a new technique to identify suppressor genes of HCC: triple-combination array analysis, which combines gene expression profile, single nucleotide polymorphism array and methylation array.

Methods. Triple-combination array analysis was performed on one HCC sample from a 68-year-old female patient, and one candidate of tumor suppressor gene was selected. Subsequently, we analyzed the identified gene by quantitative real-time reverse-transcriptase polymerase chain reaction (PCR) and methylation-specific PCR in samples from 48 HCC patients and in nine cell lines.

Results. Using this method, protein tyrosine kinase 7 (PTK7) was detected as a candidate of tumor suppressor gene. PTK7 gene is located on 6q21.2, and expression was reduced in HCC tissues at the high level of -2.5 compared with normal tissues. PTK7 locus did not show any deletion or amplification in the SNP array. The methylation value (0-1.0) in the tumor sample was 0.825 compared to 0.047 in normal tissues, indicating high methylation in tumor tissues in the methylation array. Of the 48 clinical samples, 30 (62.5%) showed PTK7 promoter hypermethylation. The PTK7 promoter hypermethylated cases were significantly low expressions status (P=0.035), and bad prognosis in both overall survival (P<0.01) and recurrence-free survival (P=0.018) compared to hypomethylated cases. On the other hand, the cases, of which the PTK7 expressions in tumor tissues decreased by more than 20% degrees compared to those in normal tissues, were significantly worse prognosis in overall survival (P=0.0136) than the other cases, but not in recurrence-free survival (P=0.3102).

Conclusions. We suggest that the PTK7 gene acts as a tumor suppressor gene in HCC. This present study indicates that triple-combination array is an available and convenient technique for detecting the genes with altered expression in disease.

Citation Format: Mitsuhiro Hishida, Shuji Nomoto, Yoshikuni Inokawa, Masamichi Hayashi, Suguru Yamada, Tsutomu Fujii, Hiroyuki Sugimoto, Shin Takeda, Yasuhiro Kodera. Identification of protein tyrosine kinase 7 gene in hepatocellular carcinoma using a novel triple-combination array analysis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1152. doi:10.1158/1538-7445.AM2013-1152
Abstract 1157: MicroRNA-625-3p is associated with response to first-line oxaliplatin-based treatment of metastatic colorectal cancer.
Authors: Rasmussen Mads H. , Jensen Niels F. , Tarpgaard Line S. , Qvortrup Camilla , Rømer Maria U. , Stenvang Jan , Hansen Tine P. , Christensen Lise-Lotte , Lindebjerg Jan , Hansen Flemming , Jensen Benny V. , Hansen Torben F. , Jakobsen Anders M. , Pfeiffer Per , Brünner Nils , Ørntoft Torben F. , Andersen Claus L.
Published: August 2014

The backbone of current oncologic treatment of metastatic colorectal cancer (mCRC) consists of fluoropyrimidine together with either oxaliplatin (XELOX/FOLFOX) or irinotecan (XELIRI/FOLFIRI). With an overall objective response rate of approximately 50% for either treatment combination, a major unsolved problem is that no predictors of response to these treatments currently are available. To address this issue, we profiled 742 microRNAs in laser-capture microdissected cancer cells from responding and non-responding patients receiving XELOX/FOLFOX as first-line treatment for mCRC, and identified, among others, high expression of miR-625-3p, miR-181b and miR-27b to be associated with poor clinical response. In a validation cohort of 98 mCRC patients treated first-line with XELOX, high expression of miR-625-3p was confirmed to be associated with poor response (OR 6.25, 95%CIOR [1.8; 21.0]). Independent analyses showed that miR-625-3p was not dysregulated between normal and cancer samples, nor was its expression associated with recurrence of stage II or III disease, indicating that miR-625-3p solely is a response marker. Finally, we also found that these miRNAs are up-regulated in oxaliplatin resistant HCT116/oxPt (miR-625-3p, miR-181b and miR-27b) and LoVo/oxPt (miR-181b) CRC cell lines as compared with their isogenic parental cells. Altogether, our results suggest an association between miR-625-3p and response to first-line oxaliplatin based chemotherapy of mCRC.

Citation Format: Mads H. Rasmussen, Niels F. Jensen, Line S. Tarpgaard, Camilla Qvortrup, Maria U. Rømer, Jan Stenvang, Tine P. Hansen, Lise-Lotte Christensen, Jan Lindebjerg, Flemming Hansen, Benny V. Jensen, Torben F. Hansen, Anders M. Jakobsen, Per Pfeiffer, Nils Brünner, Torben F. Ørntoft, Claus L. Andersen. MicroRNA-625-3p is associated with response to first-line oxaliplatin-based treatment of metastatic colorectal cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1157. doi:10.1158/1538-7445.AM2013-1157
Abstract 1162: Caspase recruitment domains: New potential markers for diagnosis of hepatocellular carcinoma in Egyptian patients.
Authors: Zekri Abdel-Rahman N. , Bahnassy Abeer
Published: August 2014

Background: Chronic HCV is a major leading cause of HCC development. Caspase Recruitment Domains (CARD) is protein modules that regulate apoptosis. Besides; numerous CARD proteins play an important role in various carcinogenesis processes. Aim: To assess the possible role of CARD9, CARD10 and Caspase only protein (COP) in progression of liver fibrosis and pathogenesis of HCC in chronic HCV G4 Egyptian patients.

Methods: One hundred and thirty patients were recruited and classified into 4 groups; group I: Chronic HCV, group II: Chronic active hepatitis, group III: Liver cirrhosis, group IV: HCV related HCC. Biochemical, virological studies, abdominal ultrasonography and liver biopsy were performed. Quantitative estimation of mRNA of CARD9, CARD10 and COP were performed by reverse transcription PCR in liver biopsy from all collected patients.

Results: In HCC patients; age, AFP and liver profile were significantly higher, HB and platelets were significantly lower, (p value <0.01). The expression levels of mRNA of CARD9, CARD10 and COP in liver biopsies of HCC group (IV) were significantly higher than other groups (p value<0.01). On differentiation between HCC and non HCC patients each CARD was assessed separately then in combination with others as follow; CARD 9, CARD 10, COP and AFP separately showed best cutoff at (87, 89.5, 20.3, 10.35) with sensitivity (80%, 90%, 90%, 87%) and specificity (80%, 63%, 81%, 68%) with positive predictive value (61%, 51.4%, 69.2%, 54%) and negative predictive value (85.7%, 93.3%, 94.8%, 91%) respectively. On combing AFP with CARD9 then CARD 10 then COP, they showed (93%, 100%, 100% sensitivity), (57%, 46%, 57% specificity), with positive predictive value (49%, 45%, 51%) and negative predictive value (94%, 100%, 100%) respectively. On combing the 3 CARDs (CARD 9, CARD 10, COP), the sensitivity was 100%, specificity was 48%, with positive predictive value 47% and negative predictive value 100% as shown in figure 1.

Conclusions: CARD9, CARD10 and COP had no role in liver fibrosis but may be involved in hepatic carcinogenesis processes and they could be used as markers for HCC diagnosis

Citation Format: Abdel-Rahman N. Zekri, Abeer Bahnassy. Caspase recruitment domains: New potential markers for diagnosis of hepatocellular carcinoma in Egyptian patients. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1162. doi:10.1158/1538-7445.AM2013-1162
Abstract 1181: Association between DNA methylation profile and neo-adjuvant treatment response in breast cancer patients.
Authors: Choi Ji-Yeob , Kim Taehyun
Published: August 2014

Epigenetic alterations are common in breast cancer, yet how these modifications contribute to chemotherapy response is poorly understood. This study aimed to define a DNA methylation profile associated with response to neo-adjuvant treatment in breast cancer and to identify possible candidate genes associated with resistance as predictors.

Eleven pre-treatment and 12 post-treatment serum samples with 6 pairs of FFPE tissues were collected in neo-adjuvant chemotherapy with operable and locally advanced breast cancer. Illumina HumanMethylation450K BeadChip technology for serum DNA and Roche Nimblegen Human DNA Methylation 3x720K CpG Island Plus RefSeq Promoter Arrays, MeDIP-chip technology for FFPE DNA were used for simultaneous analysis of 450,000 CpG sites for serum DNA and 27,728 for FFPE DNA, respectively.

Genes generated from pre-treatment samples were compared with those genes obtained from post-treatment samples, which showed differential modulation following neo-adjuvant chemotherapy. Association on 11 pre-treatment serum DNA highlighted 102 genes significantly related to Ki67 level change as the treatment response (p =0.2) after excluding genes changed by neo-adjuvant chemotherapy. Among them, 16 genes showed consistent methylation levels between serum and tissue (hypermethylation including ITIH3, p-value=0.0015, 8.9 fold-change; hypomethylation including ARID3A, p-value=0.0037, 1.4 fold-change). Hypomethylation of DBH, PRDM16, SLC12A7 and VSX2 in pre-treatment serum and tissue DNA were also predicted to another response surrogate measured by the changes of tumor size (p =0.2).

Our study suggests that testing for methylation levels of genes identified in this study may be beneficial in predicting individual patient response to neo-adjuvant therapies.

Citation Format: Ji-Yeob Choi, Taehyun Kim. Association between DNA methylation profile and neo-adjuvant treatment response in breast cancer patients. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1181. doi:10.1158/1538-7445.AM2013-1181