bluuebunny/crossref_metadata_2025 huggingface dataset:
Quercetin Increases Hepatic Homocysteine Remethylation and Transsulfuration in Rats Fed a Methionine-Enriched Diet
Authors: Meng Bin , Gao Weina , Wei Jingyu , Pu Lingling , Tang Zhenchuang , Guo Changjiang
Published: October 2015

This study was aimed at investigating the effects of quercetin on mRNA expression and activity of critical enzymes in homocysteine metabolism in rats fed a methionine-enriched diet. Rats were fed for 6 weeks the following diets, that is, control, 0.5% quercetin, 1.0% methionine, and 1.0% methionine plus 0.5% quercetin diets. Serum homocysteine was significantly increased after methionine treatment and decreased after the addition of quercetin. The mRNA expression of methionine synthase was significantly increased after methionine or methionine plus quercetin supplementation, while its enzymatic activity was significantly increased after methionine plus quercetin supplementation. The mRNA expression and enzymatic activity of cystathionineβ-synthase and cystathionineγ-lyase were upregulated after quercetin, methionine, or quercetin plus methionine treatment and a more significant increase was observed for hepatic cystathionineβ-synthase in the methionine plus quercetin treated rats, suggesting an interaction between methionine and quercetin. Meanwhile, hepatic ratio of S-adenosylmethionine to S-adenosylhomocysteine was significantly decreased in response to methionine supplementation and normalized after the addition of quercetin. It is concluded that quercetin reduces serum homocysteine by increasing remethylation and transsulfuration of homocysteine in rats exposed to a methionine-enriched diet.
Inflammation, Oxidative Stress, and Antioxidants Contribute to Selected Sleep Quality and Cardiometabolic Health Relationships: A Cross‐Sectional Study
Authors: Kanagasabai Thirumagal , Ardern Chris I.
Published: October 2015

Sleep is vital for cardiometabolic health, but a societal shift toward poor sleep is a prominent feature of many modern cultures. Concurrently, factors such as diet and lifestyle have also changed and may mediate the relationship between sleep quality and cardiometabolic health. Objectives were to explore (1) the interrelationship and (2) mediating effect of inflammation, oxidative stress, and antioxidants on sleep quality and cardiometabolic health. Cross‐sectional data from the US National Health and Nutritional Examination Survey 2005‐06 (≥20 y; N = 2,072) was used. Cardiometabolic health was defined as per the Joint Interim Statement; overall sleep quality was determined from six sleep habits and categorized as good, fair, poor, and very poor. Fair quality sleepers had optimal inflammation, oxidative stress, and antioxidant levels. Inflammation was above the current clinical reference range across all sleep quality categories, while oxidative stress was only within the clinical reference range for fair sleep quality. Selected sleep quality‐cardiometabolic health relationships were mediated by inflammation, oxidative stress, and antioxidants and were moderated by sex. Our results provide initial evidence of a potential role for inflammation, oxidative stress, and antioxidants in the pathway between poor sleep quality‐cardiometabolic decline. Further prospective research is needed to confirm our results.
Evaluation of the Inhibitory Effects of Bavachinin and Bavachin on Human Monoamine Oxidases A and B
Authors: Zarmouh Najla O. , Mazzio Elizabeth A. , Elshami Faisel M. , Messeha Samia S. , Eyunni Suresh V. K. , Soliman Karam F. A.
Published: October 2015

Monoamine oxidase B inhibitors (MAO-BIs) are used in the early management of Parkinson’s disease (PD). Long-term suspected side effects of MAO-B classical inhibitors established the need for safer alternative therapeutic agents. In our study, the flavanone bavachinin (BNN) and its analog bavachin (BVN) found in the seeds ofPsoralea corylifoliaL. ethanolic extract (PCSEE) were investigated for theirhumanMAO-A and MAO-B (hMAO-A andhMAO-B) inhibition. Both PCSEE and BNN effectively reducedhMAO-B activity more thanhMAO-A while BVN had activating effects. BNN showed selectivehMAO-B inhibition (IC50 ~ 8.82 μM) more thanhMAO-A (IC502009;~ 189.28 μM). BNN in the crude extract was determined by HPLC, also validated by TLC showing a yield of 0.21% PCSEE dry weight. BNN competitively inhibitedhMAO-A andhMAO-B, with a lowerhMAO-BKithanhMAO-AKiby 10.33-fold, and reducedhMAO-BKm/Vmaxefficiency ratio to be comparable to the standard selegiline. Molecular docking examination of BNN and BVN predicted an indirect role of BNN C7-methoxy group for its higher affinity, selectivity, and reversibility as an MAO-BI. These findings suggest that BNN, which is known to be a potent PPAR-γagonist, is a selective and competitivehMAO-B inhibitor and could be used in the management of PD.
An Integrative Literature Review of Organisational Factors Associated with Admission and Discharge Delays in Critical Care
Authors: Peltonen Laura-Maria , McCallum Louise , Siirala Eriikka , Haataja Marjaana , Lundgrén-Laine Heljä , Salanterä Sanna , Lin Frances
Published: October 2015

The literature shows that delayed admission to the intensive care unit (ICU) and discharge delays from the ICU are associated with increased adverse events and higher costs. Identifying factors related to delays will provide information to practice improvements, which contribute to better patient outcomes. The aim of this integrative review was to explore the incidence of patients’ admission and discharge delays in critical care and to identify organisational factors associated with these delays. Seven studies were included. The major findings are as follows: (1) explanatory research about discharge delays is scarce and one study on admission delays was found, (2) delays are a common problem mostly due to organisational factors, occurring in 38% of admissions and 22–67% of discharges, and (3) redesigning care processes by improving information management and coordination between units and interdisciplinary teams could reduce discharge delays. In conclusion, patient outcomes can be improved through efficient and safe care processes. More exploratory research is needed to identify factors that contribute to admission and discharge delays to provide evidence for clinical practice improvements. Shortening delays requires an interdisciplinary and multifaceted approach to the whole patient flow process. Conclusions should be made with caution due to the limited number of articles included in this review.
Dynamic Pressure of Seabed around Buried Pipelines in Shallow Water
Authors: Fu Changjing , Li Guoying , Zhao Tianlong , Guan Donghai
Published: October 2015

Due to the obvious nonlinear effect caused by the shallow waves, the nonlinear wave loads have a great influence on the buried pipelines in shallow water. In order to ensure their stability, the forces on the pipelines that resulted from nonlinear waves should be considered thoroughly. Based on the Biot consolidation theory and the first-order approximate cnoidal wave theory, analytical solutions of the pore water pressure around the buried pipelines in shallow water caused by waves are firstly derived in this paper. The dynamic response of the seabed around the pipelines under the action of irregular waves is explored in laboratory, and the results are compared with the analytical ones. Experiments show that the maximum value of the pore water pressure is at the upper part of the pipelines, and the value at the bottom of the pipelines is the minimum. The pore water pressure amplitude at the upper half of the seabed that arises from waves has a larger fluctuation, and the amplitude at the lower half remains stable. For the sandy seabed, the pore water pressure at the same depth changes over time, with the fluctuating amplitude, and the theoretical values meet well with the test results.
Challenges of Diabetes Self-Management in Adults Affected by Food Insecurity in a Large Urban Centre of Ontario, Canada
Authors: Chan Justine , DeMelo Margaret , Gingras Jacqui , Gucciardi Enza
Published: October 2015

Objective.To explore how food insecurity affects individuals’ ability to manage their diabetes, as narrated by participants living in a large, culturally diverse urban centre.Design.Qualitative study comprising of in-depth interviews, using a semistructured interview guide.Setting.Participants were recruited from the local community, three community health centres, and a community-based diabetes education centre servicing a low-income population in Toronto, Ontario, Canada.Participants.Twenty-one English-speaking adults with a diagnosis of diabetes and having experienced food insecurity in the past year (based on three screening questions).Method.Using six phases of analysis, we used qualitative, deductive thematic analysis to transcribe, code, and analyze participant interviews.Main Findings.Three themes emerged from our analysis of participants’ experiences of living with food insecurity and diabetes: (1) barriers to accessing and preparing food, (2) social isolation, and (3) enhancing agency and resilience.Conclusion.Food insecurity appears to negatively impact diabetes self-management. Healthcare professionals need to be cognizant of resources, skills, and supports appropriate for people with diabetes affected by food insecurity. Study findings suggest foci for enhancing diabetes self-management support.
Energy Hole Minimization with Field Division for Energy Efficient Routing in WSNs
Authors: Latif Kamran , Javaid Nadeem , Saqib Malik Najmus , Khan Zahoor Ali , Qasim Umar , Mahmood Basharat , Ilahi Manzoor
Published: October 2015

We analyze performance of famous cluster based routing protocols and identify the factors affecting energy consumption in wireless sensor networks (WSNs). From theoretical and experimental analysis, it is observed that communication distance and cluster node density are the major sources in the formation of energy and coverage holes. To overcome these deficiencies, we propose a new hybrid approach of static clustering and dynamic selection of cluster heads. We also conduct a comprehensive energy consumption analysis of our technique with selected existing ones. Simulation results show that the proposed technique is relatively better in terms of energy holes minimization and network lifetime prolongation.
A Phase I/II Multicenter, Open-Label Study of the Oral Histone Deacetylase Inhibitor Abexinostat in Relapsed/Refractory Lymphoma
Authors: Evens Andrew M. , Balasubramanian Sriram , Vose Julie M. , Harb Wael , Gordon Leo I. , Langdon Robert , Sprague Julian , Sirisawad Mint , Mani Chitra , Yue Jeanne , Luan Ying , Horton Sharon , Graef Thorsten , Bartlett Nancy L.
Published: October 2015

Purpose: Additional targeted therapeutics are needed for the treatment of lymphoma. Abexinostat is an oral pan-histone deacetylase inhibitor (HDACi) displaying potent activity in preclinical models. We conducted a multicenter phase I/II study (N = 55) with single-agent abexinostat in relapsed/refractory lymphoma.

Experimental Design: In phase I, 25 heavily pretreated patients with any lymphoma subtype received oral abexinostat ranging from 30 to 60 mg/m2 twice daily 5 days/week for 3 weeks or 7 days/week given every other week. Phase II evaluated abexinostat at the maximum tolerated dose in 30 patients with relapsed/refractory follicular lymphoma or mantle cell lymphoma.

Results: The recommended phase II dose was 45 mg/m2 twice daily (90 mg/m2 total), 7 days/week given every other week. Of the 30 follicular lymphoma and mantle cell lymphoma patients enrolled in phase II, 25 (14 follicular lymphoma, 11 mantle cell lymphoma) were response-evaluable. Tumor size was reduced in 86% of follicular lymphoma patients with an investigator-assessed ORR of 64.3% for evaluable patients [intent-to-treat (ITT) ORR 56.3%]. Median duration of response was not reached, and median progression-free survival (PFS) was 20.5 months (1.2–22.3+). Of responding follicular lymphoma patients, 89% were on study/drug >8 months. In mantle cell lymphoma, the ORR was 27.3% for evaluable patients (ITT ORR 21.4%), and median PFS was 3.9 months (range, 0.1–11.5). Grade 3–4 treatment-related adverse events (phase II) with ≥10% incidence were thrombocytopenia (20%), fatigue (16.7%), and neutropenia (13.3%) with rare QTc prolongation and no deaths.

Conclusions: The pan-HDACi, abexinostat, was overall well tolerated and had significant clinical activity in follicular lymphoma, including highly durable responses in this multiply relapsed patient population. Clin Cancer Res; 22(5); 1059–66. ©2015 AACR.
Abstract A01: MYC regulates glutathione depletion and glutamine utilization via miR-18a in vivo
Authors: Anderton Brittany , Balakrishnan Asha , Balakrishnan Sanjeev , Lim Lionel , Kohnz Rebecca , Nomura Dan , Goga Andrei
Published: October 2015

Recent research suggests that MYC activation in tumor cells leads to a unique metabolic phenotype that is characterized by glutamine addiction and TCA cycle activation. We wish to identify novel metabolic pathways that are altered in MYC-driven cancer in vivo. To that end, we have performed microarray-based transcriptomics and mass-spectrometry-based metabolomics profiling of tumors from a murine model of MYC-driven liver cancer. Using Fisher's exact test, we have identified glutathione metabolism as the most significantly enriched pathway across the two datasets. Notably, both the reduced and oxidized isoforms of glutathione, a major cellular antioxidant, are depleted in tumors relative to naïve control livers. We find that the rate-limiting enzyme of glutathione synthesis, Gclc, is attenuated by a MYC-regulated microRNA miR-18a. Loss of glutathione production is concomitant with increased glutamine conversion into TCA cycle metabolites in vivo. Despite loss of glutathione and another antioxidant, NADPH, our MYC-driven tumors do not exhibit markers of elevated oxidative stress. Instead, they appear to upregulate a host of alternative antioxidant pathways including Vitamin C and thioredoxins. In summary, while it is well established that MYC-driven tumors have increased dependence on glutamine resulting in increased glutamate production, whether MYC also regulates glutamate utilization decisions remains poorly understood. Here we show that MYC can regulate glutamate flux by attenuating glutathione production, shifting glutamate utilization towards the TCA cycle.

Citation Format: Brittany Anderton, Asha Balakrishnan, Sanjeev Balakrishnan, Lionel Lim, Rebecca Kohnz, Dan Nomura, Andrei Goga. MYC regulates glutathione depletion and glutamine utilization via miR-18a in vivo. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A01.
Abstract A03: Integrative analyses reveal distinct metabolic dysregulation in MYC-driven, basal breast cancer
Authors: Camarda Roman , Balakrishnan Sanjeev , Zhou Alicia Y. , Anderton Brittany , Eyob Henok , Kohnz Rebecca , Nomura Daniel K. , Goga Andrei
Published: October 2015

Dysregulated metabolism is a hallmark of all human cancers. The observation that tumors display unique changes in metabolism led to the hypothesis that tumors may be dependent upon an altered metabolic state. c-MYC (MYC) is a proto-oncogene and transcription factor activated in many cancers that regulates multiple metabolic pathways. Our lab and others have shown that MYC is activated in a large proportion of basal-like breast cancer, the most aggressive subtype of human breast cancer. However, the role of MYC in basal breast cancer metabolism is largely unknown. No efficacious MYC inhibitor is available for clinical use, however, an alternative treatment strategy is to target cellular pathways required in the context of MYC activation. We hypothesize that basal-like breast cancer harbors distinct, MYC-driven metabolic dysregulation, and that this dysregulation can be targeted therapeutically to induce MYC-dependent synthetic lethality. Utilizing in vitro and in vivo models of MYC-driven and basal breast cancer, including patient-derived cell lines and patient-derived xenograft mouse tumor models, we have performed metabolomic and transcriptomic analyses. We investigate MYC-dependent metabolic dysregulation via integrated analyses of these datasets, and find distinct changes that could reveal essential metabolic pathways for MYC-driven, basal tumorigenesis.

Citation Format: Roman Camarda, Sanjeev Balakrishnan, Alicia Y. Zhou, Brittany Anderton, Henok Eyob, Rebecca Kohnz, Daniel K. Nomura, Andrei Goga. Integrative analyses reveal distinct metabolic dysregulation in MYC-driven, basal breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A03.
Abstract A04: Metabolic reprogramming of MYCN amplified neuroblastoma
Authors: Morrison Monique , Khuu Scott , Schiffman Joshua , Cairns Bradley , Rutter Jared , Winge Dennis , Speleman Frank , Stewart Rodney
Published: October 2015

Neuroblastoma (NB) is a highly malignant embryonic tumor of neural crest origin and accounts for 15% of all cancer deaths in children. Amplification of the MYCN oncogene, which occurs in ~25% of patients, is the most reliable marker of metastatic disease and predicts poor outcome. Recent findings show MYCN reprograms NB cell metabolism to promote glycolysis and shunting of glutamate into the TCA cycle, causing dependence on increased levels of TCA intermediates, such as a-KG and succinate. Allelic loss of the short arm of chromosome 1, (1p36) is associated with the vast majority of MYCN amplified NB, and a candidate tumor suppressor gene (TSG) in this region is succinate dehydrogenase subunit B,SDHB, which encodes a core component of the succinate dehydrogenase (SDH) complex, converting succinate to fumarate. We show that MYCN-amplified NB cells, with 1p deletion, have reduced SDHB protein levels and elevated succinate levels. Thus, we are now testing a model that the combined loss of SDH activity with MYCN amplification causes dramatic accumulation of cytosolic succinate, which in turn stabilizes HIF1α to accelerate NB pathogenesis in vivo. To test this model, we have generated mutations in zebrafish sdhb to determine if 1) it is normally required for sympathetic neuron differentiation and 2) cooperates with MYCN to accelerate zebrafish NB in vivo (Zhu et. al, Cancer Cell, 2012). As HIF1a is predicted to be upregulated in SDH-deficient cells, as well as MYCN-amplified NB, we have also generated stable HIF1α transgenic zebrafish lines to directly determine if HIF1α alone is sufficient to drive NB or cooperates with MYCN to accelerate it. The results from our studies of sdhb loss and hif1α gain on peripheral sympathetic nervous system development and NB formation in vivo will be discussed as well as potential therapeutic approaches to target SDH/MYCN-dependent tumors.

Citation Format: Monique Morrison, Scott Khuu, Joshua Schiffman, Bradley Cairns, Jared Rutter, Dennis Winge, Frank Speleman, Rodney Stewart. Metabolic reprogramming of MYCN amplified neuroblastoma. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A04.
Abstract A11: Biophysical characterization of the b-HLH-LZ of deltaMax
Authors: Maltais Loïka , Tremblay Cynthia , Bédard Mikaël , Montagne Martin , Lavigne Pierre
Published: October 2015

Myc proteins (N-, L- and c-Myc) are transcriptional regulators with a broad spectrum of target genes. While essential for development, cell growth and proliferation as well as apoptosis, they play a major role in cancer onset and progression when deregulated. Myc protein functions depend on their heterodimerization with Max, another transcriptional regulator capable of forming a homodimer and antagonizing c-Myc transcriptional regulation. Recent studies have shown that c-Myc can control the alternative splicing of Max's pre-messenger RNA to produce a c-terminal truncated isoform called deltaMax. The ratio of deltaMax/WT-Max (p21) in cancer cells correlates with increased malignancy. In addition to producing a shorter gene product, the alternative splicing (exon-inclusion) generates a change in sequence in the LZ. The LZ domain is an integral and crucial part of the b-HLH-LZ motif of Max controlling its homodimerization and specific heterodimerization with c-Myc as well as binding to the E-box sequences found in gene promoters and enhancers. Whereas it has been demonstrated that deltaMax increases c-Myc transcriptional activities, the underlying mechanisms have not been elucidated yet. Here, we provide original insights into such mechanisms. First, we show that contrary to the WT motif, the b-HLH-LZ of deltaMax does not homodimerize. In addition, while the b-HLH-LZ of deltaMax can still heterodimerize with the b-HLH-LZ of c-Myc, it can no longer compete with the binding of the heterodimer to E-box sequences. Taken together, our results demonstrate that deltaMax can maximize the amount of c-Myc bound target gene promoters and enhancers and explain how deltaMax and the ratio of deltaMax/WT-Max (p21) in cancer cells can increase c-Myc oncogenic activities.

Citation Format: Loïka Maltais, Cynthia Tremblay, Mikaël Bédard, Martin Montagne, Pierre Lavigne. Biophysical characterization of the b-HLH-LZ of deltaMax. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A11.
Abstract A14: Epigenetic alterations reactivate a novel mechanism of Myc-induced apoptosis
Authors: Adams Clare M. , Eischen Christine M.
Published: October 2015

Cancer initiation and progression is often driven by dysregulation of the Myc oncoprotein. The tumorigenic consequences of aberrant Myc expression emerge from its potential to broadly regulate gene expression. Alterations in gene expression resulting from specific epigenetic modifications contribute to the Myc oncogenic program to facilitate tumor development. As such, inhibitors targeting a certain class of chromatin-modifying enzymes have demonstrated therapeutic potential in treating malignancies, resulting in selective killing of cancer cells. However, the molecular events underlying the tumor cell-selective apoptosis are incompletely resolved. We determined that inhibition of specific epigenetic-modifying enzymes in cancers of hematopoietic and non-hematopoietic origin relieved the Myc-mediated transcriptional repression of specific genes. This transcriptional switch resulted in Myc-driven upregulation of these genes, which subsequently decreased the expression of crucial pro-survival genes, inducing apoptosis in multiple cancers. Furthermore, we demonstrated that Myc transcriptionally upregulated these genes in normal cells as a means to prevent cellular transformation, revealing a mechanism whereby Myc induces apoptosis independent of the p53 tumor suppressor. Our data reveal a Myc-regulated mechanism of cell death that underlies the apoptotic consequences of inhibiting a class of epigenetic modifiers. This apoptotic mechanism offers new insights that should aid in improving therapies for the 70% of human cancers that have dysregulated MYC.

Note: This abstract was not presented at the conference.

Citation Format: Clare M. Adams, Christine M. Eischen. Epigenetic alterations reactivate a novel mechanism of Myc-induced apoptosis. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A14.
Abstract A38: The role of MGA loss-of-function mutations in lung adenocarcinomas
Authors: Zhang Xiaoyang , Francis Joshua , Lin Charles , Rahl Peter , Bradner James , Young Richard
Published: October 2015

MYC activation promotes tumorigenesis in a wide range of tissues. The Cancer Genome Atlas project has recently reported that MGA, encoding a potential suppressor of MYC activity, is significantly mutated in lung adenocarcinomas and the majority of mutations are loss-of-function. Roughly 10% of lung adenocarcinoma cases acquire either MGA loss-of-function mutations or homozygous deletions. Employing functional genomics methodologies, we aimed to characterize the role of MGA mutations in lung adenocarcinoma, with an emphasis on studying their involvement in modulating MYC activity. Using CRISPR knockout technologies, we showed that MGA inactivation induces cellular transformation of primary lung epithelium cells AALE, suggesting that MGA acts as a tumor suppressor. In addition, by performing chromatin immunoprecipitation-sequencing (ChIP-seq) and RNA-sequencing (RNA-seq) assays, we showed that MGA competes with MYC for a subset of DNA-binding sites and represses the expression of genes nearby. Finally, we revealed that the gene repression function of MGA is due to its association with the HDAC1/2 complex. The discovery of MGA mutations defines a new pathway in lung adenocarcinoma: the MYC/MAX/MGA pathway. Our study not only illuminates the activity MGA mutant lung adenocarcinomas but also those tumors with amplifications of MYC.

Citation Format: Xiaoyang Zhang, Joshua Francis, Charles Lin, Peter Rahl, James Bradner, Richard Young. The role of MGA loss-of-function mutations in lung adenocarcinomas. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A38.
Abstract A46: Regulation of genomic Myc binding by Pin1 in serum-stimulated fibroblasts
Authors: Su Yulong , Pelz Carl , Impey Soren , Sears Rosalie
Published: October 2015

The transcription factor Myc's induction of its pro-oncogenic target genes is regulated by Serine62 (S62) phosphorylation and the Pin1 prolyl-isomerase, where pS62-Myc is isomerized at Proline63 by Pin1 and this facilitates its recruitment to select target gene promoters. It is also known that Myc is an early serum response gene that controls cellular transition from quiescence to proliferation. In order to examine the global effects of Pin1 on Myc activity, we have performed unbiased genome-wide RNA-seq and ChIP-seq for Myc in primary murine embryo fibroblasts (MEFs) derived from Pin1 wild-type and knockout mice. The MEFs were serum starved for 72 hours and serum stimulated for 4 hours. Through RNA-seq we have observed a striking blunting of serum responsive genes in the Pin1 null cells. From our highly reproducible ChIP-seq data (6719 regions, IDR<0.1, Pin1 wild-type, stimulated), we found that both the number and magnitude of Myc DNA binding peaks were reduced in the null cells in genes showing blunted serum response. Using functional annotation analysis tools (DAVID and GSEA), we found opposing pathway-enrichments for Myc binding in null versus wild-type cells, with proliferation and migration genes enriched in wild-type cells. Furthermore, binding motif analysis of Myc-binding sites suggested a stronger enrichment of canonical E-box motif (CACGTG) in wild-type cells over null cells. In summary, our study suggested a key role that Pin1 plays in Myc global DNA binding activity.

Citation Format: Yulong Su, Carl Pelz, Soren Impey, Rosalie Sears. Regulation of genomic Myc binding by Pin1 in serum-stimulated fibroblasts. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A46.
Abstract A47: Gene regulation by Myc during B cell activation
Authors: Tesi Alessandra , Sabò Arianna , Bianchi Valerio , Morelli Marco , Pelizzola Mattia , Amati Bruno
Published: October 2015

Myc is required for the response of cells to proliferative stimuli, as shown for example in fibroblasts or B-cells. Cellular activation entails the regulation of specific transcriptional programs concomitant with a general increase in RNA production (also termed “amplification”), which will need to be carefully disentangled for a full understanding of the mitogenic response. Upon activation of quiescent fibroblasts with serum, c-myc is rapidly induced, and is required for the subsequent activation of a set of ca. 300 genes (Myc-Dependent Serum Response, or MDSR genes) in the early-mid G1 phase of the cell cycle (1). This is followed by RNA amplification, concomitant with the G1-S transition (2). Deletion of the c-myc gene prior to serum stimulation led to a loss of all of these responses: these data indicated that Myc primarily acts to selectively regulate specific gene programs, with RNA amplification occurring as a secondary consequence (2). This is in apparent contrast with previous studies on B-cells and tumors, in which Myc was proposed to directly drive transcriptional amplification at all active loci (3, 4). Here, we addressed Myc-dependent responses in primary mouse B-cells, based on conditional deletion of c-myc followed by LPS stimulation. Our data indicate that, as in fibroblasts, a discrete set of Myc-dependent genes can be identified in B-cells: the response of these genes occurs prior to general RNA amplification, and is not entirely attributable to overt promoter/enhancer invasion by Myc. Together with our previous studies (see poster by A. Sabò et al.) (2), these data provide a unifying view of Myc' s action in different cell types, with amplification occurring as an indirect effect, following from the action of specific Myc-target genes on cellular physiology and metabolism. Systematic work is needed to unravel which of the numerous Myc-regulated genes are critical in mediating this chain of events.

References:

1. Perna D, et al. (2012) Genome-wide mapping of Myc binding and gene regulation in serum-stimulated fibroblasts. Oncogene 31, 1695-1709.

2. Sabo A, et al. (2014) Selective transcriptional regulation by Myc in cellular growth control and lymphomagenesis. Nature 511, 488-492.

3. Nie Z, et al. (2012) c-Myc is a universal amplifier of expressed genes in lymphocytes and embryonic stem cells. Cell 151, 68-79.

4. Lin CY, et al. (2012) Transcriptional amplification in tumor cells with elevated c-Myc. Cell 151, 56-67.

Citation Format: Alessandra Tesi, Arianna Sabò, Valerio Bianchi, Marco Morelli, Mattia Pelizzola, Bruno Amati. Gene regulation by Myc during B cell activation. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A47.
Abstract A48: Gene expression signatures associated with MYC oncogene addiction in lymphoma
Authors: Koch Daniel , Adams Stacey , Gentles Andrew , Anchang Benedict , Sullivan Delaney , Plevritis Sylvia , Felsher Dean
Published: October 2015

c-MYC is a bHLH transcription factor that heterodimerizes with MAX to form an active transcription factor complex that binds to promoter regions across the genome. MYC is a potent oncogene that promotes tumorigenesis in many cell types. Several studies have shown that tumor cells can be dependent on proto-oncogenes such as MYC, a state called “oncogene addiction.” Recent findings have revealed that c-myc amplifies active gene programs, and our group has previously identified a unique MYC transcriptional signature. In an effort to understand how MYC regulates discrete transcriptional programs across the genome we searched for potential cofactors that coordinate with MYC. Using computational approaches we examined several publically available human data sets as well as our own conditional MYC murine model for potential co-factor interactions. We have determined that several Jumonji family members coordinate with MYC expression. Currently, we are using CRISPR/Cas9 mediated disruption of target genes in murine cells to investigate whether these genes have a casual role in MYC oncogene addiction.

Citation Format: Daniel Koch, Stacey Adams, Andrew Gentles, Benedict Anchang, Delaney Sullivan, Sylvia Plevritis, Dean Felsher. Gene expression signatures associated with MYC oncogene addiction in lymphoma. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A48.
Abstract B09: Myc is required for maintenance of KRasG12D-driven pancreatic cancer and its associated microenvironment
Authors: Sodir Nicole M. , Swigart Lamorna Brown , Kortlever Roderik M. , Littlewood Trevor D. , Soucek Laura , Arends Mark J. , Evan Gerard I.
Published: October 2015

Deregulation of Myc is observed in most, if not all, human cancers making it an attractive therapeutic target. Indeed, recent studies demonstrate that Myc inhibition (via expression of a dominant negative Myc mutant) triggers regression of SV40-driven pancreatic islet tumors and KRasG12D-driven lung tumors in mice. Myc inhibition in insulinomas elicits regression presaged by collapse of the tumor microenvironment and involution of the tumor vasculature. A characteristic feature of human pancreatic ductal adenocarcinoma (PDAC) is an extensive stromal component (desmoplasia) that is thought to contribute to the resistance of PDAC to current therapies. We show that systemic Myc inhibition in KRasG12D-driven mouse PDAC triggers regression of both tumor and its associated desmoplastic stroma, indicating that endogenous Myc function in the tumor cells is required for maintenance of the desmoplastic reaction. Consistent with this, deregulated expression of physiological levels of Myc enhances pancreatic tumor progression and promotes local immune evasion and stromal desmoplasia. Reversal of deregulated Myc activity results in reversion of these features indicating that they are dependent on Myc activity. The ubiquity of Myc in tumor development and maintenance indicates that it serves an essential and non-redundant role, coupling diverse intracellular oncogenic pathways to the tumor microenvironment, and underscoring its credentials as a pharmacological target in cancers driven by different oncogenes and arising in different tissues.

Citation Format: Nicole M. Sodir, Lamorna Brown Swigart, Roderik M. Kortlever, Trevor D. Littlewood, Laura Soucek, Mark J. Arends, Gerard I. Evan. Myc is required for maintenance of KRasG12D-driven pancreatic cancer and its associated microenvironment. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr B09.
Abstract B10: Genome-wide analysis of p53 transcriptional programs in Myc-induced lymphomas
Authors: Tonelli Claudia , Morelli Marco J. , Sabò Arianna , Piontini Andrea , Pelizzola Mattia , Campaner Stefano , Amati Bruno
Published: October 2015

Oncogenic activation of Myc induces cellular transformation and hyper-proliferation, while it activates intrinsic tumor surveillance pathways aimed at restraining the expansion of pre-cancerous cells. All these Myc-induced tumor suppressive mechanisms converge on p53, and loss of p53 activity is the major selected event in lymphomagenesis. Yet, the genetic programs triggered by p53 in tumor suppression have been only partially clarified. Using whole genome mapping of p53 binding and gene expression profiling, we investigated the transcriptional circuitry employed by p53 in suppressing cancer development. We studied the progression of Myc-induced lymphomas in Eµ-myc transgenic mice, as well as the regression of these lymphomas following restoration of p53 function, by either pharmacological or genetic means. We thus identified a set of p53 target genes that are strong candidates for mediating tumor suppression. Currently, we are testing the impact of these new components of the p53 transcriptional program on tumorigenesis with an RNA interference (RNAi)-based functional genetic screen. Altogether our data expand our understanding of the p53 response to Myc-induced oncogenic stress and will hopefully highlight new tumor suppressive mechanisms, paving the way for their therapeutic application.

Citation Format: Claudia Tonelli, Marco J. Morelli, Arianna Sabò, Andrea Piontini, Mattia Pelizzola, Stefano Campaner, Bruno Amati. Genome-wide analysis of p53 transcriptional programs in Myc-induced lymphomas. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr B10.
Abstract B11: Expression and functional analysis of aurora kinase A/B in double hit and triple hit B-cell lymphomas
Authors: Cinar Munevver , Peker Deniz , Akyurek Nalan , Huang Qin , Lopategui Jean , Cinar Bekir , Alkan Serhan
Published: October 2015

Background: Double-hit lymphoma (DHL) or triple-hit lymphoma (THL) is associated with translocations of MYC along with the genomic rearrangements of BCL-2 and BCL-6. MYC is demonstrated to upregulate Aurora kinase (AURK) A and B expression, which is implicated in MYC-driven lymphomagenesis. Although a novel AURK inhibitor MLN8237 showed promising treatment outcomes in a phase II clinical trial in patients with various lymphomas including B-cell lineage, expression patterns and functional inhibition of AURK A and B in DHL and THL remains to be determined.

Methods: Expression patterns of AURK A and B proteins in DHL (15 BCL2+; 4 BCL6+ cases), THL (1 case) and reactive lymphoid hyperplasia were analyzed by IHC in formalin-fixed, paraffin-embedded tissues utilizing AURK A and B specific antibodies. Cases with strong nuclear staining in more than 30% of lymphoma cells were scored positive. Cell viability by MTS assays and apoptosis by flow cytometry were assessed in DoGKiT DHL cell line and CS-THL1 THL cell line at 72h post treatment with AURK inhibitor MLN8237 single or combination with DNA methyltransferase inhibitor, Decitabine (DAC), proteasome inhibitor, Bortezomib (BTZ) or classical chemotherapeutic agent, Doxorubicin (DOX).

Results: All cases of DHL (19/19) showed nuclear positivity for AURK A and B; THL was AURK A reactive but AURK B noted only in 5% of the cells. AURK A expression in reactive hyperplasia was diffuse in germinal center cells (GCC) and AURK B had prominence in the dark zone of the GCC, but no significant expression seen in mantle or marginal zone cells. Combine exposure of MLN8237 with DAC, Bortezomib or DOX synergistically attenuated growth of DoGKiT and CS-THL1cells compare to single agent in vitro.

Conclusion: AURK A and B expression is common in DHL and THL. AURK inhibitor exposure attenuated growth and induced apoptosis particularly in combination with DAC, BTZ and DOX. Thus, targeted therapy against AURK A and B should be considered in future clinical trials for the development of effective treatment modalities for DHL or THL.

Note: This abstract was not presented at the conference.

Citation Format: Munevver Cinar, Deniz Peker, Nalan Akyurek, Qin Huang, Jean Lopategui, Bekir Cinar, Serhan Alkan. Expression and functional analysis of aurora kinase A/B in double hit and triple hit B-cell lymphomas. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr B11.
Abstract B12: Co-targeting of MYC and BCL2 signaling is a promising treatment strategy for double hit and triple hit B-cell lymphomas
Authors: Cinar Munevver , Rosenfelt Fred , Rokshar Sepehr , Pillai Raju , Lopategui Jean , Cervania Melissa , Cinar Bekir , Alkan Serhan
Published: October 2015

Background: Overexpression of MYC and BCL2 or/and BCL6 due to genomic rearrangements is the key molecular feature of double hit lymphoma (DHL) or triple hit lymphoma (THL). Patients with DHL and THL show very aggressive disease course and poor survival because there is no effective treatment modality. The objective of this study is to assess the impact of MYC and BCL2 inhibition on established DHL and patient derived THL cells in vitro.

Methods: Primary THL cell line named as CS-THL1 was established from an 85 year-old lymphoma patient. Immunohistochemistry (IHC) was conducted to determine the levels of MYC, BCL2, BCL6, or Ki-67 expression in formalin-fixed, paraffin-embedded tissues. MTS assays were employed to evaluate the anti-growth efficacy of MYC inhibitor 10058-F4 or JQ-1, and BCL-2 inhibitor ABT-199, a BH3 mimetic, in CS-THL1 and DoGKiT cells alone or together and with or without vincristine or doxorubicin. Apoptosis, cytochrome c release and intracellular expression of BCL2, BCL-xL, BIM, and MCL-1 protein in response to drugs were analyzed by flow cytometry.

Results: Expression of MYC, BCL2, BCL6 and proliferation factor Ki-67 protein was increased in THL, as shown by IHC. Analysis of cell viability demonstrated that inhibition of MYC by 10058-F4 or JQ-1 or BCL2 by ABT-199 as a single agent significantly attenuated the growth of CS-THL1 and DoGKiT cells in dose- and time-dependent manners. Combination of 10058-F4 or JQ-1 and ABT-199 or together with vincristine or doxorubicin synergistically suppressed CS-THL1 and DoGKiT cell growth compared with single agent treatment. As demonstrated by multiple approaches, apoptosis due to inhibition of BCL2 by ABT-199 or inhibition of MYC with 10058-F4 or JQ-1 exposure was the underlying cause of the observed growth retardation in CS-THL1 and DoGKiT cells.

Conclusion: These observations suggest that concurrent inhibition of MYC and BCL2 pathway signaling is a potential treatment modality for patients with aggressive DH and TH B-cell lymphomas.

Citation Format: Munevver Cinar, Fred Rosenfelt, Sepehr Rokshar, Raju Pillai, Jean Lopategui, Melissa Cervania, Bekir Cinar, Serhan Alkan. Co-targeting of MYC and BCL2 signaling is a promising treatment strategy for double hit and triple hit B-cell lymphomas. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr B12.
Abstract B19: MYC induces PLD6 to suppress YAP/TAZ-dependent self-renewal of mammary stem cells
Authors: Eyss Bjoern von , Jaenicke Laura Annika , Wiese Katrin , Rosenwald Andreas , Eilers Martin
Published: October 2015

For the maintenance of a given tissue it is absolutely critical to balance proliferation and differentiation of stem cells, progenitor cells and terminally differentiated cells. Perturbations of these finely tuned processes can lead to various diseases such as cancer.

One factor that has been implicated in the transition from a stem cell to a progenitor/ transit-amplifying cell is the oncogenic transcription factor MYC. Paradoxically, despite its strong pro-tumorigenic capabilities it has been shown to promote differentiation in several tissues such as the skin or the hematopoietic system.

To identify critical pathways that might explain MYC's effect on the differentiation of epithelial stem cells we expressed MYC in mammary stem cells. Here, MYC induction led to a drastic reduction in sphere formation indicative of a decreased stem cell potential. Further RNA-Seq and bioinformatical analysis revealed that one of MYC's main functions in mammary stem cells is the repression of YAP/TAZ target genes.

YAP and its orthologue TAZ act as nuclear co-activators and are the downstream effectors of the Hippo pathway, a recently discovered pathway with key functions in adult stem cell maintenance and growth control.

Using a targeted siRNA screen for MYC target genes we were able to identify a single target gene that is absolutely essential for MYC's ability to repress YAP/TAZ, namely PLD6.

PLD6 is a mitochondrial protein that promotes mitochondrial fusion, so that this MYC target gene couples a mitochondrial checkpoint to repression of YAP/TAZ.

We were also able to demonstrate the relevance of this pathway in vivo using a mouse that expresses MYC in the mammary stem cell compartment. Interestingly, this pathway is also operational in human breast cancer since a high MYC signature correlates with a low YAP/TAZ signatue in breast cancer patients ultimately leading to a bad prognosis for the respective patient.

In summary, we were able to identify a new pathway that couples MYC to mitochondrial biogenesis and the repression of an adult stem cell program.

Citation Format: Bjoern von Eyss, Laura Annika Jaenicke, Katrin Wiese, Andreas Rosenwald, Martin Eilers. MYC induces PLD6 to suppress YAP/TAZ-dependent self-renewal of mammary stem cells. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr B19.
Abstract B24: Targeting ERK-MYC axis in pancreatic cancer
Authors: Beglyarova Natalia , Banina Eugenia , Skobeleva Natalya , Khazak Vladimir , Astsaturov Igor
Published: October 2015

Pancreatic cancer (PCa) is a devastating malignancy with almost 90% lethality of all stages. In PCa, constitutively activated mutated KRAS induces persistent ERK signaling which stabilizes the oncogenic MYC protein. With very limited efficacy of chemotherapy, novel treatment options are urgently need for PCa.

Here, we used patient-derived PCa cells and matched PCa tissue explants (PDX) to search for cytotoxic anti-PCa activity among the existing 867 drugs. Only a minority of tested agents were confirmed as active in vivo on patient-matched PDX models. From a short list of the agents with activity in vivo, we focused on triptolide (TLD), an irreversible inhibitor of ERCC3. In pilot testing of triptolide efficacy in a “xenopatient” trial of 8 PCa PDX models, we found that TLD was highly effective against a minority of tumors which achieved complete regression lasting for 3-6 weeks, while other models only showed growth delay. Genomic profiling of highly sensitive PDX models unfirmly demonstrated MYC-amplification.

We tested TLD activity in vitro using PDX-matched patient-derived PCa cell lines. Nanomolar TLD elicited rapid (1-4 hours) and profound depletion of MYC oncoprotein in MYC-amplified PCa cell lines, but in PCa cells with normal MYC gene copy number. Furthermore, TLD-resistant PCa cells and PDX tumors exhibited rapid increase of phosphorylated ERK and its downstream targets including stable phospho-MYC protein. This activity of TLD against non-phosphorylated forms of MYC protein suggests interdependence of ERCC3 and MYC in cancer. Expression of ERCC3 was MYC-dependent in a Tet-OFF MYC cell line model. Conversely, silencing of ERCC3 suppressed MYC level.

The KRAS->ERK pathway is critical for initiation and progression of PCa. Attempts to disrupt this signaling axis by blocking MEK activity produces only transient cytostatic effect followed by rapid reactivation of the pathway mediated by MYC. Our results further confirm this dependency of PCa on the integrity of the activated KRAS->ERK->MYC signaling axis, and that pharmacological blockade of ERCC3 can be a highly effective strategy against PCa, and in other recalcitrant carcinomas with MYC-amplification. We thus provide a useful biomarker for future clinical development of TLD analogs such as Minnelide which is currently being tested in a Phase I clinical trial.

Citation Format: Natalia Beglyarova, Eugenia Banina, Natalya Skobeleva, Vladimir Khazak, Igor Astsaturov. Targeting ERK-MYC axis in pancreatic cancer. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr B24.