bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract LB-344: Vascular normalization as an emerging strategy to enhance cancer immunotherapy.
Authors: Huang Yuhui , Yuan Jianping , Righi Elda , Duda Dan G. , Fukumura Dai , Poznanasky Mark C. , Jain Rakesh K.
Published: August 2014

The recent approval of a prostate cancer vaccine has renewed hope for anti-cancer immunotherapies. However, the immunosuppressive tumor microenvironment may limit the effectiveness of current immunotherapies. Antiangiogenic agents have the potential to modulate the tumor microenvironment and improve immunotherapy, but they are often used at high doses in the clinic to prune tumor vessels and may paradoxically compromise various therapies. Here, we demonstrate that targeting tumor vasculature with lower “vascular normalizing” doses, but not high “anti-vascular/anti-angiogenic” doses of an anti-vascular endothelial growth factor receptor 2 (VEGFR2) antibody results in a more homogeneous distribution of functional tumor vessels. Furthermore, lower doses are superior to the high doses at polarizing tumor-associated macrophages from immune inhibitory M2-like towards immune stimulatory M1-like phenotype, and in facilitating CD4+ and CD8+ T cell tumor infiltration. Based on this mechanism, scheduling lower dose anti-VEGFR2 therapy with T cell activation induced by a whole cancer cell vaccine therapy enhanced anti-cancer efficacy in a CD8+ T cell-dependent manner in both immune tolerant and immunogenic murine breast cancer models. These findings indicate that vascular normalizing lower doses of anti-VEGFR2 antibody can reprogram the tumor microenvironment away from immunosuppression toward potentiation of cancer vaccine therapies. Given that the combinations of high doses of bevacizumab with chemotherapy have not improved overall survival of breast cancer patients, our study suggests a new strategy to more effectively use antiangiogenic agents in breast cancer with active immunotherapy and potentially other anti-cancer therapies.

Citation Format: Yuhui Huang, Jianping Yuan, Elda Righi, Dan G. Duda, Dai Fukumura, Mark C. Poznanasky, Rakesh K. Jain. Vascular normalization as an emerging strategy to enhance cancer immunotherapy. [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 LB-344. doi:10.1158/1538-7445.AM2013-LB-344

Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.
Abstract LB-36: JAK2/STAT5 inhibition circumvents resistance to PI3K/mTOR blockade: A rationale for co-targeting these pathways in metastatic breast cancer.
Authors: Britschgi Adrian , Andraos Rita , Brinkhaus Heike , Klebba Inna , Murakami Masato , Romanet Vincent , Müller Urs , Radimerski Thomas , Bentires-Alj Mohamed
Published: August 2014

Hyperactive PI3K/mTOR signaling is prevalent in the majority of human malignancies (1) and its inhibition exhibits potent antitumor activity in a wide spectrum of solid cancers. Unfortunately, single-agent targeted cancer therapy is usually short-lived and thwarted by different resistance mechanisms (2). Here, we report the discovery of a JAK2/STAT5-evoked positive feedback loop that causes adaptive resistance to dual PI3K/mTOR inhibition. Mechanistically, PI3K/mTOR inhibition increased IRS1-dependent activation of JAK2/STAT5 and secretion of IL-8 in several cell lines and primary triple-negative breast tumors. Genetic or pharmacological inhibition of JAK2 abrogated this vicious feedback loop. Combined PI3K/mTOR and JAK2 inhibition synergistically reduced cancer cell viability in vitro as well as tumor growth in vivo, and decreased tumor seeding and metastasis due to its impact on the IL-8 receptor CXCR1+ tumor-initiating subpopulation of cells. We further found that combined PI3K/mTOR and JAK2 inhibition increased event-free as a well as overall survival of tumor bearing animals. This study reveals a new link between growth factor signaling, JAK/STAT activation, cytokine secretion and metastasis. Our results provide a rationale for combined targeting of the PI3K/mTOR and JAK2/STAT5 pathways in triple-negative breast cancer, a particularly aggressive and currently incurable disease.

Citation Format: Adrian Britschgi, Rita Andraos, Heike Brinkhaus, Inna Klebba, Masato Murakami, Vincent Romanet, Urs Müller, Thomas Radimerski, Mohamed Bentires-Alj. JAK2/STAT5 inhibition circumvents resistance to PI3K/mTOR blockade: A rationale for co-targeting these pathways in metastatic breast 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 LB-36. doi:10.1158/1538-7445.AM2013-LB-36
Abstract LB-54: Identification of a RAF inhibitory auto-phosphorylation site.
Authors: Holderfield Matthew , Merritt Hanne , Lin Julie , Gao Zenhai , Stuart Darrin , McCormick Frank
Published: August 2014

Preclinical studies have demonstrated that BRAF wild-type cancer cells are not only refractory but paradoxically activate the MAPK pathway when treated with RAF inhibitors. Potentially through a related mechanism, multiple point mutations in the activation loop and Phosphate binding loop (P. loop) domains of BRAF have been characterized in human cancers, which often render BRAF catalytically impaired, yet stimulate phosphorylation of downstream targets in cells. However, the underlying biochemistry causing these phenomena has yet to be fully understood. In this study we investigate the biochemical mechanism of wild-type RAF activation in response to RAF inhibitor treatment and identify a novel auto-phosphorylation site within the well conserved BRAF/CRAF P. loop. Disruption of the auto-phosphorylation, either through pharmacologic or genetic alterations, results in activation of the MAPK pathway. This work offers new insight into RAF biochemistry by uncovering a previously unrecognized regulatory mechanism of RAF kinases that is bypassed by the BRAF oncoproteins.

Citation Format: Matthew Holderfield, Hanne Merritt, Julie Lin, Zenhai Gao, Darrin Stuart, Frank McCormick. Identification of a RAF inhibitory auto-phosphorylation site. [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 LB-54. doi:10.1158/1538-7445.AM2013-LB-54
Abstract LB-55: Comparing effects of individual Ras isoforms on cell signaling and growth.
Authors: Pitt Cameron L. , McCormick Frank
Published: August 2014

Though proteins in the Ras family signal primarily through identical effectors, each isoform displays unique preferential coupling to cancer types. Membrane localization following modification at the C-terminus is required for Ras activation and downstream signaling. This step provides an avenue for signaling diversity, as the C-terminus is the only site of significant sequence variability between Ras proteins. Differential post-transcriptional modifications at the C-terminus produce different patterns of membrane binding and trafficking between isoforms. Broken up into varied membrane domains, each isoform has unique combinatorial access to activators and repressors of signaling as well as downstream molecules in pathways critical to cancer initiation and tumor maintenance. Introducing individual Ras isoforms around endogenous levels to cells originally devoid of expression of all of the major Ras isoforms has allowed us to separate their effects on cell signaling and interrogate key differences. Expression of any of the four major Ras isoforms is sufficient to restore growth of "Rasless" cells. Our findings display that Ras isoforms are differentially activated by growth factor stimulation and act primarily through different pathways. Expression of N-Ras or K-Ras 4A alone promotes more rapid growth than H-Ras or K-Ras 4B expression alone, likely due to increased pro-apoptotic signaling from H-Ras and K-Ras 4B. H-Ras is uniquely activated by IGF-1 and insulin to signal through PI3K to pAKT. While the kinetics of MAPK activation in response to growth factors vary depending on the Ras isoform expressed, the amplitude of the response through pERK is greatest in N-Ras and K-Ras expressing cells. We are currently performing comparative expression analysis of the downstream components of these two major Ras effector pathways to begin to mechanistically explain the differences observed in signaling. We are also using mutants of the Ras isoforms at the sites that differentiate their processing to determine whether differences in localization due to protein modifications cause a shift in the PI3K/MAPK signaling balance and account for isoform-dependent differences in cells relying on Ras signaling for growth.

Citation Format: Cameron L. Pitt, Frank McCormick. Comparing effects of individual Ras isoforms on cell signaling and growth. [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 LB-55. doi:10.1158/1538-7445.AM2013-LB-55
Abstract LB-7: The high-risk subject screening of ESCC by iTRAQ-coupled 2D LC-MS/MS.
Authors: Li Xiu-Min
Published: August 2014

Esophageal squamous cell carcinoma (ESCC) remains the leading cause of cancer-related deaths in China and the prognosis is very poor, the 5-year survival rate for ESCC at late stage is only about 15%. The molecular mechanism of poor prognosis is not clear. This study was to determine the changes of proteins associated with poor survival using protein profiling, Five ml of peripheral blood was taken from each ESCC patient. All the patients were followed up for more than 5 years. Based on the survival time, the patients were divided into three groups, i.e. ≤3 years (n=10), 3-5 years (n=10) and ≥5 years (n=10). Serum protein profiles for different groups were determined by the iTRAQ-coupled LC-MS/MS technique. We found that overall, 3987 different peptide spectra were identified, of which 556 were non-redundant proteins. Interestingly, 54 proteins showed over-expressed, and Carbonic anhydrase 1&2;Angiotensinogen; Collectin-10; 22kDa protein were associated with poor prognosis; 50 proteins were down-expressed in ESCC, and Alpha-2-macroglobulin; Apolipoprotein D; Isoform 14 of Fibronectin; V2-7 protein; Adiponectin; Transthyretin were associated with poor prognosis. Of the identified proteins, some (such as alpha-2-macroglobulin; apolipoprotein D; angiotensinogen; carbonic anhydrase 1 &2) have been reported to be related with metastasis and recurrence of the tumor. Further verification to these proteins may shed light on identifying novel candidate protein biomarkers for high-risk subject screening for ESCC and for prediction of poor prognosis.

Citation Format: Xiu-Min Li. The high-risk subject screening of ESCC by iTRAQ-coupled 2D LC-MS/MS. [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 LB-7. doi:10.1158/1538-7445.AM2013-LB-7
Abstract LB-78: Detection of circulating cell-free DNA is enhanced by targeting short fragments: high concordance of the KRAS and BRAF mutation status from plasma analysis, with tumor-tissue analysis in colorectal cancer..
Authors: Mouliere Florent , Pang Dalong , Messaoudi Safia El , Pezet Denis , Mathonnet Muriel , Ychou Marc , Dritschilo Anatoly , Thierry Alain R.
Published: August 2014

We investigated size distributions of circulating cell-free DNA (ccfDNA) to determine its value as a potential theranostic tool. CcfDNA quantification by Q-PCR was optimal when amplifying target lengths between 60 and 100 bp. CcfDNA sizes were previously believed to be greater than the length of the DNA per nucleosome (~180 bp). Q-PCR analyses of plasma samples from xenografted mice and from colorectal cancer (CRC) patients showed that tumor derived ccfDNA exhibited specific profiles of ccfDNA sizes with significantly higher ccfDNA fragmentation than was observed in samples from healthy individuals. Atomic Force Microscopy analysis confirmed these observations and, for the first time, enables visual representation of ccfDNA molecules. CcfDNA from plasma of CRC patients exhibited a median size of 135 bp and 88% of ccfDNAs are less than 180 bp in size. Based on these observations, we developed a refined single-step Allele Specific Q-PCR based method (Intplex) with improved specificity and sensitivity for enabling single-copy detection of variant alleles to a sensitivity of ≥ 0.005% mutant to WT ratio. We performed a blinded prospective study to compare KRAS and BRAF mutation status data by analysis of tumor tissue of CRC patients by standard methods and of plasma DNA (n=79). CcfDNA analysis showed 100% specificity and sensitivity for the BRAF V600E mutation. For the six tested KRAS point mutations, the method exhibited 100% specificity and 87% sensitivity with a concordance value of 96%. Mutation load expressed as the proportion of mutant alleles in ccfDNA, was highly variable (0.03% to 69%, median, 10.9%; n=128) and was determined in the plasma of every patient at stage I, II, III and IV (100% success rate). Tumor-derived ccfDNA did not correspond to "a tiny fraction" as it has been previously stated and it is likely not derived mainly from stroma cells. CcfDNA analysis could replace advantageously tumor-section analysis for determining KRAS and BRAF mutation status and expand the scope of personalized medicine for cancer patients.

Citation Format: Florent Mouliere, Dalong Pang, Safia El Messaoudi, Denis Pezet, Muriel Mathonnet, Marc Ychou, Anatoly Dritschilo, Alain R. Thierry. Detection of circulating cell-free DNA is enhanced by targeting short fragments: high concordance of the KRAS and BRAF mutation status from plasma analysis, with tumor-tissue analysis in 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 LB-78. doi:10.1158/1538-7445.AM2013-LB-78
Abstract LB-93: Calculating the statistical significance of synergy in cancer drug combinations.
Authors: Sult Erin , Zhao Wei , Yang Harry , Hollingsworth Robert , Sachsenmeier Kris F.
Published: August 2014

Single agent treatment in cancer often results in drug resistance and limited survival. Multi-drug treatment may overcome resistance to monotherapies given the heterogeneous nature of tumors. This may result in improved survival, increased efficacy and lower toxicity. Bliss Independence and Loewes Additivity are widely accepted methods for evaluating synergy with drug combinations, however these applications typically lack statistical significance. We have developed a novel Response-Surface (RS) method that enables us to identify statistically significant synergy at a 95% confidence level. In this presentation, the RS method will be described, compared to traditional methods, and applied to dual-drug combinations across various cancer cell models.

Citation Format: Erin Sult, Wei Zhao, Harry Yang, Robert Hollingsworth, Kris F. Sachsenmeier. Calculating the statistical significance of synergy in cancer drug combinations. [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 LB-93. doi:10.1158/1538-7445.AM2013-LB-93
Abstract LB-95: Construction and application of elastin-like polypeptide containing IL-4 receptor targeting peptide.
Authors: Devi Sarangthem Vijaya , Park Rang-Woon
Published: August 2014

Cancer cells express a number of cell surface and matrix proteins that mediate tumor growth, migration, invasion, and metastasis. Screening for ligands that specifically target these molecules represents an excellent cancer therapy strategy. AP1 is a recently discovered peptide, homing onto atherosclerotic plaques and breast tumor tissues through selective binding to the interleukin 4 receptor (IL-4R). IL-4Rs are highly expressed in a variety of human tumors and it has been reported that IL-4/IL-4R interactions amplify the expression of some anti-apoptotic proteins thereby preventing drug-induced cancer cell death. Thus, targeting the IL-4R could possibly increase the therapeutic efficacy of anticancer drugs. Even though AP1 peptide possesses high target specificity and efficient tumor-homing, it has limitation due to easy elimination from the circulation and short half-life. To improve the binding affinity of AP1 and its avidity towards the IL-4R as well as its half-life, we incorporated multiple AP1 peptides into the elastin-like polypeptides (ELPs). Tandem repeats of ELP polymers containing AP1 peptide (AP1-ELPs) were prepared by using recursive directional ligation (RDL) method. The fluorescence-labeled A6V72, an AP1-ELP containing six AP1 units displayed superior binding ability to the IL-4R expressing cancer cell lines, H226 and MDA-MB-231. Surface plasmon resonance analysis showed that multivalent presentation of the targeting ligand AP1 in the ELP polymer backbone increased binding affinity to IL-4R approximately ~10, 000-fold compared to the free AP1 peptide, which is important for tumor targeting approach. The binding of AP1-ELPs was remarkably reduced when IL-4Rs were blocked with antibody against IL-4 receptor. Confocal microscopic imaging revealed the increased accumulation and uptake of A6V72 than V84 control ELP by H226 cells. Furthermore, the Cy5.5-labeled AP1-ELP showed excellent homing and longer retention in xenografted tumor tissues in mouse model. Immunohistological analysis of excised tumor tissues further verified the targeting of AP1-ELP to tumor. The present results imply that the AP1-ELPs can serve as novel carriers for effective delivery of therapeutic drugs to tumors.

Citation Format: Sarangthem Vijaya Devi, Rang-Woon Park. Construction and application of elastin-like polypeptide containing IL-4 receptor targeting peptide. [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 LB-95. doi:10.1158/1538-7445.AM2013-LB-95
Abstract SY03-01: Genotypic and phenotypic features of de novo and acquired resistance to cancer therapies.
Authors: Dancey Janet E.
Published: August 2014

Drug resistance is the single cause of cancer treatment failure resulting in cancer related death. Despite its paramount importance, our mechanistic understanding and means of circumventing cancer drug resistance is limited. In the current era, the evolutionary processes in cancer development and progression have been elucidated and provide insights into the biology of cancer and in particular cancer heterogeneity. However, our understanding of the contribution of evolutionary processes and tumor heterogeneity to the development of drug resistance is limited. As a result, our ability to translate knowledge into effective clinical strategies is similarly limited and remains largely on the use combination chemotherapy based on Goldie and Coldman's principles first described in 1984. Pragmatically, resistance may be de novo (i.e. treatment has no effect) or acquired (i.e. treatment had initial effect but tumors eventually progress due to repopulation by resistant cells). De novo resistance is thus equivalent to primary refractoriness and acquired resistance is emergent in the presence and presumably as a direct response to the selective pressures imposed by therapy. Mechanisms of resistance may be divided into various categories; however, a simple construct is to consider resistance as a manifestation of failure of one or more of the following: drug delivery, drug uptake, drug-target interaction and cellular response and cellular adaptation. Genetic, epigenetic, physiochemical and spatial properties of cancers may contribute to drug resistance and it is likely that different mechanisms of drug resistance develop concomitantly. The most important challenge is how to tackle the interrelated problems of tumor genetic and epigenetic heterogeneity and drug resistance in cancer using rational drug selections. The identification of tumor dependencies driven by dominant oncogenes, hormones, or metabolites may prove vulnerable to regimens designed to intercept them assuming dependencies are identifiable, targets or target pathways are “druggable” and such agents and combinations are tolerable and effective for cancer patients. Although the issues are complex, they can and should be addressed. Serial and comprehensive sampling to identify genetic and epigenetic changes of tumor to guide drug therapy will be required as will identifying susceptibilities such as oncogene addiction, synthetic lethality and genomic instability. Rational selection of drug dose, schedule and combination partners can follow. Treatment advances will occur to the extent that mechanisms of resistance can be identified or predicted and circumvented.

Citation Format: Janet E. Dancey. Genotypic and phenotypic features of de novo and acquired resistance to cancer therapies. [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 SY03-01. doi:10.1158/1538-7445.AM2013-SY03-01
Abstract SY06-01: Targeting IAP proteins for the treatment of cancer.
Authors: Vucic Domagoj
Published: August 2014

Evasion of cell death is a characteristic feature of human cancers and represents a key cause of resistance to current treatment approaches. Therefore, reactivation of cell death programs in cancer cells is a promising strategy to overcome treatment resistance, one of the major unsolved problems in clinical oncology. Inhibitor of apoptosis (IAP) protein family members block cell death in response to diverse stimuli and are expressed at elevated levels in the majority of human malignancies, which makes them attractive targets for developing a novel class of cancer therapeutics. We have designed small-molecule IAP antagonists (smac mimetics) that bind with high affinities to select baculovirus IAP repeat (BIR) domains of IAPs resulting in a dramatic induction of c IAP auto-ubiquitination activity and rapid proteasomal degradation. IAP antagonists inhibit tumor growth in vivo as single agents and in combination with a number of anti-tumor agents. Using several different proteomic approaches we have discovered novel binding partners for IAP proteins and determined the spatial and temporal pattern of endogenous IAP-mediated ubiquitination during proliferative, apoptotic and necrotic signaling. The differential expression levels and posttranslational modifications of identified proteins will be used to build diagnostic profiles for the treatment with IAP antagonists. These compounds can be used in the treatment of malignancies in which IAP expression contributes to tumor progression and resistance to conventional chemotherapeutic agents.

Citation Format: Domagoj Vucic. Targeting IAP proteins for the treatment of 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 SY06-01. doi:10.1158/1538-7445.AM2013-SY06-01
Abstract SY28-02: Tumor targeting with antimitotic monoclonal antibody drug conjugates.
Authors: Senter Peter
Published: August 2014

Monoclonal antibodies (mAbs) have played a major role in cancer medicine, with active drugs such as trastuzumab, cetuximab, bevacizumab and rituximab in a wide range of therapeutic applications. The mechanism of activity of these agents involves cell signaling, effector functions through interactions with Fcγ receptor positive cells, and complement fixation. The activity of mAbs can be enhanced through the generation of antibody drug conjugates (ADCs) that are capable of delivering cytotoxic agents with some degree of selectivity to tumor cells. Early work in this field involved the use of clinically approved anticancer drugs that generally were low in potency. Consequently, the resulting ADCs had suboptimal activities. Because of this, significant attention was directed towards the identification of appropriate drugs for targeted delivery, the most successful being antimitotic drugs such as monomethyl auristatin E (MMAE), and maytansinoids. These drugs inhibit tubulin polymerization and arrest cell growth in a cell-cycle dependent manner. Successful delivery of these agents requires drug, linker, and conjugation optimization, in addition to judicious selection of an antigen target on tumor cell surfaces. Brentuximab vedotin, a conjugate comprised of the anti-CD30 mAb cAC10 conjugated with MMAE through a highly stable peptide linker, is an example of how addressing these considerations can lead to ADCs with pronounced clinical efficacy. In August 2011, brentuximab vedotin received accelerated approval by the US Food and Drug Administration for use in relapsed or refractory Hodgkin lymphoma and relapsed or refractory systemic anaplastic large cell lymphoma, two diseases with significant unmet medical needs. An overview of how this targeted antimitotic drug was developed and how we are extending the technology will be provided.

Citation Format: Peter Senter. Tumor targeting with antimitotic monoclonal antibody drug conjugates. [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 SY28-02. doi:10.1158/1538-7445.AM2013-SY28-02
Abstract SY36-03: Hijacking homeostatsis: How heterogeneity drives tumor progression and treatment failure.
Authors: Anderson Alexander RA
Published: August 2014

Heterogeneity in cancer is an observed fact, both genotypically and phenotypically. Cell-cell variation is seen in almost all aspects of cancer from early development all the way through to invasion and subsequent metastasis. Our current understanding of this heterogeneity has mainly focused at the genetic scale with little information on how this variation translates to actual changes in cell phenotypic behavior. Given that many genotypes can lead to the same cellular phenotype, it is important that we quantify the range and scope of this heterogeneity at the phenotypic scale as ultimately this variability will dictate the aggressiveness of the tumor and its treatability. Central to our understanding of this heterogeneity is how the tumor cells interact with each other and with their microenvironment. Since it is these very interactions that drive selection and that ultimately define the ecology of the tissue in which the tumor is developing. Considering an organ as an ecological system, means that we should view normal tissue homeostasis as an equilibrium that cancer cells must disrupt if they are to be successful. Disruption of this equilibrium is often one of the first events in cancer development, as the normal control mechanisms of the tissue are damaged or ignored. We will discuss the interplay between homeostasis, heterogeneity, evolution and ecology in cancer progression and treatment failure with an emphasis on the metabolism of breast cancer.

Citation Format: Alexander RA Anderson. Hijacking homeostatsis: How heterogeneity drives tumor progression and treatment failure. [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 SY36-03. doi:10.1158/1538-7445.AM2013-SY36-03
Abstract A26: Role of Dermcidin in Tumorigenesis of Skin Cancers
Authors: Sangiuliano Beatriz A. , Perez Marcela Nancy , Cadurin Aline , Aguiar Andrew , Moreira Dayson F. , Belizario Jose E.
Published: August 2014

Dermcidin (DCD) is a candidate oncogene localized at 12q13.1. It is produced by benign melanocytic naevi and dark cells of eccrine sweat glands and proteolytic processed and transported via sweat to the epidermal surface to act as peptide antibotic, but it is not induced under inflammation. We have established the role of DCD in melanoma growth and survival by silencing DCD expression in human melanoma G361 cell line and overexpression in murine melanoma B16 cell line. Downregulation of DCD in G-361 cell line significantly reduced cellular resistance to cytotoxic agents. Balb/c Nude mice inoculated with 1x106 G-361 cells underwent a progressive increase in the tumor size and body weight loss, whereas animals inoculated with G-361-IBC I melanoma cells expressing DCD shRNA, we observed a significant difference in tumor volumes. Moreover, administration of rabbit polyclonal antibody against DCD in mice bearing G361 xenografts for four weeks delayed tumor growth. To examine tumor heterogeneity we isolated by FACS cell sorting specific cancer-stem cell populations based on cell size and enhanced tumorigenic capacity in Nude mice. In parallel, we are employing the microarray and exome methodologies to define genes that are up- and downregulated, patterns of genetic modifications and gene mutation in specific oncogenic pathways to evaluate the hypothesis that DCD control multiple oncogenic stimuli (EGFR/HER2, C-MYC, PI3K/AKT/mTOR, VEGF, BRAF/RAS, etc.). We will summarize these results and highlight genetic and biological mechanisms suggesting that DCD functions as tumor growth and cell survival factor.

Citation Format: Beatriz A. Sangiuliano, Marcela Nancy Perez, Aline Cadurin, Andrew Aguiar, Dayson F. Moreira, Jose E. Belizario. Role of Dermcidin in Tumorigenesis of Skin Cancers [abstract]. In: Proceedings of the AACR Special Conference on Chemical Systems Biology: Assembling and Interrogating Computational Models of the Cancer Cell by Chemical Perturbations; 2012 Jun 27-30; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2012;72(13 Suppl):Abstract nr A26.
Abstract A35: Discovery of driver-type therapeutic targets to reverse glucocorticoid resistance in T-ALL
Authors: Yu Jiyang , Piovan Ericah , Flaherty Maria Sol , Silva Jose , Ferrando Adolfo , Califano Andrea
Published: August 2014

Glucocorticoid (GC) resistance is a major driver of therapeutic failure in T-cell acute lymphoblastic leukemia (T-ALL). Here we developed a systems biology framework, Network-based Bayesian Inference of Disease Drivers (NetBID2), using transcriptomic data, to predict signaling or regulatory factors driving GC-resistance in T-ALL. With this algorithm, we identified the AKT1 kinase as a signaling modulator of GC-resistance. Mechanistically, AKT1 directly phosphorylates the glucocorticoid receptor (GCR) NR3C1 protein at position S134 and blocks glucocorticoid-induced NR3C1 translocation to the nucleus. Consistently, pharmacologic inhibition of AKT1 increases the response of T-ALL cells to glucocorticoid therapy and effectively reverses glucocorticoid resistance in vitro and in vivo. These results warrant the clinical testing of ATK1 inhibitors and glucocorticoids in combination for the treatment of T-ALL.

Genome-wide RNA interference screening emerges as a powerful tool for loss-of-function studies and searching for new therapeutic targets of diseases. We integrated this technology with our computational framework and identified 16 master regulators of GC-resistance in T-ALL, when repressed, sensitizing resistant cells. Out of 16 candidates, 13 were validated in vitro, and 10 outperformed positive controls. Moreover, 75% of only predicted drivers demonstrated significant effects on changing GC-sensitivity. Network analysis of validated drivers indicated that they might work cooperatively to induce resistance, suggesting potential combinatorial therapies to reverse GC-resistance in T-ALL.

Citation Format: Jiyang Yu, Ericah Piovan, Maria Sol Flaherty, Jose Silva, Adolfo Ferrando, Andrea Califano. Discovery of driver-type therapeutic targets to reverse glucocorticoid resistance in T-ALL [abstract]. In: Proceedings of the AACR Special Conference on Chemical Systems Biology: Assembling and Interrogating Computational Models of the Cancer Cell by Chemical Perturbations; 2012 Jun 27-30; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2012;72(13 Suppl):Abstract nr A35.
Abstract A4: Two dimensional chemical interrogation of oncogenic systems and multi-omics integration of signatures reveals novel signaling pathways involved in the pathophysiology of cancer
Authors: Vishnudas Vivek K. , Du Min , Akmaev Viatscheslav , Sarangarajan Rangaprasad , Narain Niven R.
Published: August 2014

Oncogenic events involve activation of kinases either in case of direct mutation or as a secondary event as recipients and mediators of oncogenic signals. Kinases transduce signals that lead to cell proliferation or inhibition of programmed cell death by activating transcription factors and inhibiting pro apoptotic molecules. Despite the knowledge and huge market for the kinases as targets, small molecule modulators have failed repeatedly to deliver as cancer therapeutics. Primarily, the failure is thought to stem from the lack of kinase discovery platforms that enable a mechanistic understanding of signaling pathways involving transmembrane and cytoplasmic kinases. The Berg Interrogative Biology® Kinase Discovery Platform offers novel technology driven solutions for understanding of kinases in oncogenesis. The approach is powered by “two-dimensional chemical interrogation” where in vitro cancer and control models were interrogated by a kinase inhibitor (sorafenib) in the first dimension. Overall changes in kinase activity were captured by a second dimension of chemical interrogation employing activity-based kinase enrichment probes. Kinases were identified by LC-MS based mass spectrometry. In addition, changes in phospho proteome in response to kinase inhibitor were captured using a phosphoprotein enrichment method followed by LC-MS for identification of proteins. Finally quantitative changes in total protein expression were obtained. Multi-omics data collated from the above mentioned approach was integrated using an AI-based informatics tool leading to generation of data-driven inference of causal networks representing differential kinase activity driving phosphorylation of proteins that are operational in cancer and not in normal models. The technology platform led to discovery of novel kinases that are mechanistically relevant to pathophysiology of cancer.

Citation Format: Vivek K. Vishnudas, Min Du, Viatscheslav Akmaev, Rangaprasad Sarangarajan, Niven R. Narain. Two dimensional chemical interrogation of oncogenic systems and multi-omics integration of signatures reveals novel signaling pathways involved in the pathophysiology of cancer [abstract]. In: Proceedings of the AACR Special Conference on Chemical Systems Biology: Assembling and Interrogating Computational Models of the Cancer Cell by Chemical Perturbations; 2012 Jun 27-30; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2012;72(13 Suppl):Abstract nr A4.
Abstract IA20: General methods to conditionally regulate protein stability
Authors: Wandless Thomas J.
Published: August 2014

There is an increasing need for experimental perturbation methods that provide scientists with a high degree of control over the proteins they study. In order to provide scientists with general techniques to conditionally regulate protein function, we have developed experimental methods to regulate protein stability rapidly and reversibly through the administration of cell-permeable small molecules to cultured cells or living animals. These perturbation strategies depend upon engineered protein domains called “destabilizing domains” that bind tightly to small molecule ligands. When a destabilizing domain is fused to a targeted protein-of-interest, investigators can tunably regulate the expression levels of the targeted fusion protein through the administration of the appropriate ligand. We have developed several experimental systems in which the addition of a ligand can be used to either stabilize or destabilize a destabilizing domain, thereby restoring or eliminating the function of the protein-of-interest.

Citation Format: Thomas J. Wandless. General methods to conditionally regulate protein stability [abstract]. In: Proceedings of the AACR Special Conference on Chemical Systems Biology: Assembling and Interrogating Computational Models of the Cancer Cell by Chemical Perturbations; 2012 Jun 27-30; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2012;72(13 Suppl):Abstract nr IA20.
Abstract IA21: Changing chasses and inventing elements: Developing a combined systems biology and engineering approach to designing complex function in cells
Authors: Arkin Adam P.
Published: August 2014

To meet the goal of creating reliable, predictable, efficient, and transparent methods to harness cellular capabilities for human benefit, it is necessary both to have standard libraries of elements from which useful pathways can be constructed and an understanding of the how host physiology and the environment impacts the functioning of these heterologous circuits. We show how variations in cellular and environmental context affect the operation of the basic central dogma functions underlying gene expression. Then we describe progress on creating a complete, scalable, and relatively homogeneous and designable sets of part families that can control central dogma function predictably in the face of varying configurations, genetic contexts, and environments. We show the challenges that arise in attempting this in applications such as a tumor destroying bacteria.

Citation Format: Adam P. Arkin. Changing chasses and inventing elements: Developing a combined systems biology and engineering approach to designing complex function in cells [abstract]. In: Proceedings of the AACR Special Conference on Chemical Systems Biology: Assembling and Interrogating Computational Models of the Cancer Cell by Chemical Perturbations; 2012 Jun 27-30; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2012;72(13 Suppl):Abstract nr IA21.
Abstract C54: Pdgfrb is an essential mediator of p53(mut)-driven metastasis in pancreatic cancer
Authors: Weissmueller Susann , Saborowski Michael , Manchado Eusebio , Thapar Vishal , Lowe Scott W.
Published: August 2014

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of cancer due to its high metastatic potential and resistance to existing treatments. Recent advances in cancer genomics have identified mutations and copy number changes that are linked to pancreatic cancer but which of these influence metastatic behavior remain poorly understood. 50-80% of PDACs carry a mutation in the TP53 tumor suppressor gene (p53(mut)), which possibly results in a gain-of-function that contributes to, amongst others, tumor cell invasiveness. Therefore the aim of this study was to explore the underlying molecular pathways of invasive PDAC that are mediated by TP53(mut). To this end, we combined cell lines, murine models, and RNA interference to confirm that p53(mut)-expressing tumors acquire a higher invasive capability, which is dependent on the continued expression of the mutant allele. In-depth transcriptional profiling of p53(mut) versus knockdown cells identified downstream mediators responsible for the gain-of-function phenotype. Specifically, we conducted a follow-up invasion screen to analyse the top 40 deregulated genes for their potential to induce invasiveness and we identified Platelet-derived growth factor receptors isoform b (Pdgfrb) as a p53(mut) downstream mediator. Moreover, we found that the expression of Pdgfrb is transcriptionally regulated by p73. In the presence of p53(mut) proteins, a direct p73-p53(mut) interaction alleviates the inhibitory effect that p73 exerts on the Pdgfrb promoter, thereby inducing Pdgfrb expression and, hence, invasiveness. Attenuating Pdgfrb levels by RNAi or a small molecule inhibitor reduced cellular invasion in a p53(mut) background, thereby mimicking the effects of p53-null cells. We confirmed these findings in several human pancreatic cancer cells. More importantly, we found that elevated Pdgfrb expression in human colorectal and ovarian cancers predicts poor metastasis-free survival, thereby confirming our hypothesis that high Pdgfrb levels drive metastases development.

Citation Format: Susann Weissmueller, Michael Saborowski, Eusebio Manchado, Vishal Thapar, Scott W. Lowe. Pdgfrb is an essential mediator of p53(mut)-driven metastasis in pancreatic cancer. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr C54.
Abstract A100: Fibrillar human serum albumin suppresses ovarian cancer metastasis by targeting β1 integrin and its downstream FAK signaling pathways
Authors: Chen Tai-An , Hung Shao-Wen , Chang Yu-Ching , Chen Chih-Yuan , Hsieh Hsin-Ying , Liang Chi-Ming , Liang Shu-Mei
Published: August 2014

Due to the high mortality caused by frequent relapse and metastasis in patients with ovarian cancer, advances in treatment remain necessary. In this study, we developed a chromatographical process which converted native protein human serum albumin (HSA) into a water-soluble nano-fibrillar protein structure and aimed to explore the potential inhibitory effect of fibrillar HSA (F-HSA) on ovarian tumor metastasis. Transwell migration assay, western blotting and gelatin zymography were used to investigate the effects of F-HSA in vitro. Its effects in vivo were evaluated in orthotopic and metastatic xenograft mouse models established using an SKOV3 ovarian cancer cell line that stably expressed green fluorescent protein and luciferase. The fibrillar structure of converted HSA was verified by transmission electron microscopy and Thioflavin T (ThT) fluorescence assay. Treatment with F-HSA decreased the viability, migration and invasion of several ovarian cancer cell lines in vitro. F-HSA bound to β1 integrin receptor to increase PTEN phosphorylation and decrease phosphorylation of FAK and Akt. The inhibitory effect of F-HSA on invasive ability of SKOV3 cells was associated with decreases in phosphorylation of Raf and Erk as well as changes in Crk phosphorylation leading to down-regulation of Rac and MMP2 activities. Orthotopic and metastatic xenograft mouse models showed that F-HSA treatment suppressed tumor growth and metastasis and prolonged survival of SKOV3-bearing mice. These results suggest that F-HSA may have great potential for development as a novel therapeutic agent for metastatic and drug-resistant ovarian cancer.

Citation Format: Tai-An Chen, Shao-Wen Hung, Yu-Ching Chang, Chih-Yuan Chen, Hsin-Ying Hsieh, Chi-Ming Liang, Shu-Mei Liang. Fibrillar human serum albumin suppresses ovarian cancer metastasis by targeting β1 integrin and its downstream FAK signaling pathways. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr A100.
Abstract A17: Regulation of EGFR: Stat3 signaling by Mig6 is required for metastatic outgrowth in triple-negative breast cancer
Authors: Wendt Mike K. , Balanis Nikolas , Schiemann Barbara , Carlin Cathleen , Schiemann William
Published: August 2014

Stat3 is an oncogene that enriches for tumor initiating breast cancer cells. Stat3 activity is driven by numerous signaling inputs, including those initiated by EGFR. Herein we shown that Stat3 is critically involved in EGFR-driven tumorigenesis as EGFR molecules harboring a mutation in the juxtamembrane domain that specifically prevents activation of Stat3 fail to transform mammary epithelial cells. Using this model of EGFR transformation, we previously established that the induction of epithelial-mesenchymal transition (EMT) enhances pulmonary tumor formation. Surprisingly, EMT drastically diminishes the capacity of EGFR to signal to Stat3. Indeed, using the MCF-10A progression series, we show that constitutive activation of Stat3 is consistent with the acquisition of a mesenchymal phenotype but independent of EGFR activity. As a compensatory mechanism, we find that EMT increases the expression and ability of fibronectin to directly activate Stat3 in an EGFR-independent, Jak2-dependent manor. Indeed, human triple-negative breast cancer (TNBC) cells that fail to activate Stat3 in response to EGF robustly activate Stat3 upon fibronectin adhesion. Consistent with these results, TNBC outgrowth in pulmonary 3D-organotypic cultures is enhanced by the addition of fibronectin, a process that is absolutely dependent on β1-integrin, Jak2 and Stat3, but independent of EGFR. Underscoring the importance of this switch from EGFR-mediated to fibronectin-mediated Stat3 activation in metastatic TNBC cells, we demonstrate that shRNA-mediated diminution of the EGFR inhibitory molecule MIG6 results in increased apoptosis and consequently, decreased pulmonary tumor formation by TNBC cells. Our data clearly demonstrate that matrix-initiated signaling is sufficient to drive Stat3 activation, a reaction that likely contributes to the resistance of metastatic TNBCs to molecular therapies, particularly those that target EGFR.

Citation Format: Mike K. Wendt, Nikolas Balanis, Barbara Schiemann, Cathleen Carlin, William Schiemann. Regulation of EGFR: Stat3 signaling by Mig6 is required for metastatic outgrowth in triple-negative breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr A17.