bluuebunny/crossref_metadata_2025 huggingface dataset:
The Application of Pediatric Ureteroscope for Seminal Vesiculoscopy
Authors: Guo Shulin , Xie Donghua , He Xiangfei , Du Chuance , Zhu Lunfeng , Deng Xiaolin , Yang Zhongsheng
Published: October 2015

To describe a novel technique of transurethral seminal vesiculoscopy using a pediatric ureteroscope in the diagnosis and management of persistent hematospermia, a retrospective study was carried out for 20 patients with recurrent hematospermia whom we evaluated and treated using a 6–7.5F (6F front end and 7.5F rear end) pediatric ureteroscope from August 2009 to September 2013. For the 20 patients, the age ranges from 25 to 48 years with a mean age of 36 years. The duration of the hematospermia ranges from 6 to 48 months with a mean duration of 18 months. Transurethral seminal vesiculoscopy was successfully performed in the 20 cases and the mean operative time was 35 min (ranges from 25 to 90 min). Among the 20 patients, 11 patients were found to have seminal vesiculitis, five were with seminal vesicle stone, one was with prostatic utricle stone, one was with prostate cyst, and one was with ejaculatory duct obstruction. The mean follow-up period was 7 months (ranged from 6 to 12 months). Hematospermia in 19 cases disappeared after the surgery and only in one patient the hematospermia recurred 6 months after the surgery. The cure rate was 95%. This study indicated that transurethral seminal vesiculoscopy could be performed easily using a semirigid pediatric ureteroscope with few complications and is an effective therapeutic approach for persistent hematospermia.
Acceptance and Avoidance Processes at Different Levels of Psychological Recovery from Enduring Mental Illness
Authors: Siqueira Vinicius R. , Oades Lindsay G.
Published: October 2015

Objective. This study examined the use of psychological acceptance and experiential avoidance, two key concepts of Acceptance and Commitment Therapy (ACT), in the psychological recovery process of people with enduring mental illness.Method. Sixty-seven participants were recruited from the metropolitan, regional, and rural areas of New South Wales, Australia. They all presented some form of chronic mental illness (at least 12 months) as reflected in DSM-IV Axis I diagnostic criteria. The Acceptance and Action Questionnaire (AAQ-19) was used to measure the presence of psychological acceptance and experiential avoidance; the Recovery Assessment Scale (RAS) was used to examine the levels of psychological recovery; and the Scales of Psychological Well-Being was used to observe if there are benefits in utilizing psychological acceptance and experiential avoidance in the recovery process.Results. An analysis of objectively quantifiable measures found no clear correlation between the use of psychological acceptance and recovery in mental illness as measured by the RAS. The data, however, showed a relationship between psychological acceptance and some components of recovery, thereby demonstrating its possible value in the recovery process.Conclusion. The major contribution of this research was the emerging correlation that was observed between psychological acceptance and positive levels of psychological well-being among individuals with mental illness.
Recent Advance in Applications of Proteomics Technologies on Traditional Chinese Medicine Research
Authors: Ji Qing , Zhu Fangshi , Liu Xuan , Li Qi , Su Shi-bing
Published: October 2015

Proteomics technology, a major component of system biology, has gained comprehensive attention in the area of medical diagnosis, drug development, and mechanism research. On the holistic and systemic theory, proteomics has a convergence with traditional Chinese medicine (TCM). In this review, we discussed the applications of proteomic technologies in diseases-TCM syndrome combination researches. We also introduced the proteomic studies on thein vivoandin vitroeffects and underlying mechanisms of TCM treatments using Chinese herbal medicine (CHM), Chinese herbal formula (CHF), and acupuncture. Furthermore, the combined studies of proteomics with other “-omics” technologies in TCM were also discussed. In summary, this report presents an overview of the recent advances in the application of proteomic technologies in TCM studies and sheds a light on the future global and further research on TCM.
Preclinical Efficacy of the MDM2 Inhibitor RG7112 in MDM2-Amplified and TP53 Wild-type Glioblastomas
Authors: Verreault Maite , Schmitt Charlotte , Goldwirt Lauriane , Pelton Kristine , Haidar Samer , Levasseur Camille , Guehennec Jeremy , Knoff David , Labussière Marianne , Marie Yannick , Ligon Azra H. , Mokhtari Karima , Hoang-Xuan Khê , Sanson Marc , Alexander Brian M. , Wen Patrick Y. , Delattre Jean-Yves , Ligon Keith L. , Idbaih Ahmed
Published: October 2015

Purpose: p53 pathway alterations are key molecular events in glioblastoma (GBM). MDM2 inhibitors increase expression and stability of p53 and are presumed to be most efficacious in patients with TP53 wild-type and MDM2-amplified cancers. However, this biomarker hypothesis has not been tested in patients or patient-derived models for GBM.

Experimental Design: We performed a preclinical evaluation of RG7112 MDM2 inhibitor, across a panel of 36 patient-derived GBM cell lines (PDCL), each genetically characterized according to their P53 pathway status. We then performed a pharmacokinetic (PK) profiling of RG7112 distribution in mice and evaluated the therapeutic activity of RG7112 in orthotopic and subcutaneous GBM models.

Results: MDM2-amplified PDCLs were 44 times more sensitive than TP53-mutated lines that showed complete resistance at therapeutically attainable concentrations (avg. IC50 of 0.52 μmol/L vs. 21.9 μmol/L). MDM4-amplified PDCLs were highly sensitive but showed intermediate response (avg. IC50 of 1.2 μmol/L), whereas response was heterogeneous in TP53 wild-type PDCLs with normal MDM2/4 levels (avg. IC50 of 7.7 μmol/L). In MDM2-amplified lines, RG7112 restored p53 activity inducing robust p21 expression and apoptosis. PK profiling of RG7112-treated PDCL intracranial xenografts demonstrated that the compound significantly crosses the blood–brain and the blood–tumor barriers. Most importantly, treatment of MDM2-amplified/TP53 wild-type PDCL-derived model (subcutaneous and orthotopic) reduced tumor growth, was cytotoxic, and significantly increased survival.

Conclusions: These data strongly support development of MDM2 inhibitors for clinical testing in MDM2-amplified GBM patients. Moreover, significant efficacy in a subset of non–MDM2-amplified models suggests that additional markers of response to MDM2 inhibitors must be identified. Clin Cancer Res; 22(5); 1185–96. ©2015 AACR.
Is It Better to Be Rich or Relaxed? Sociobiology Meets Bone Marrow Transplant
Authors: Turcotte Lucie M. , Verneris Michael R.
Published: October 2015

Low socioeconomic status in hematopoietic cell transplant recipients is associated with increased treatment-related mortality and relapse, resulting in reduced survival. No biologic mechanism has been identified for these associations. The stress-related gene expression profile, termed the “conserved transcriptional response to adversity,” may be a predictor of these negative outcomes. Clin Cancer Res; 22(1); 6–8. ©2015 AACR.

See related article by Knight et al., p. 69
Abstract A02: The epigenetic modifier CHAF1A opposes neuroblastoma differentiation via metabolic reprogramming
Authors: Barbieri Eveline , Chen Zaowen , Moreno-Smith Mirthala , Shohet Jason M.
Published: October 2015

Background. Neuroblastoma (NB) arises from embryonal neural crest secondary to a block in differentiation and long-term survival inversely correlates with degree of neuronal differentiation. Metabolic rewiring is an important feature of undifferentiated NB tumors. Interestingly, MYCN down regulation precedes differentiation of NB cells induced by retinoic acid (RA) and genetic MYCN silencing leads to neuronal differentiation. We have recently demonstrated a novel function for the histone chaperone CHAF1A in blocking NB differentiation. CHAF1A is a subunit of the Chromatin Assembly Factor-1 (CAF1), which regulates H3K9-trimethylation and DNA methylation.

Methods. Morphological and molecular evaluations of NB differentiation were assessed upon CHAF1A silencing in RA-sensitive and RA-resistant lines by neurite outgrowth assays and Q-PCR for mature neuronal markers. Gene expression profiling of CHAF1A knockdown and control cell lines was performed on the Affymetrix U133+2.0 arrays. GSEA (Gene Set Enrichment Analysis) defined the transcriptional response to CHAF1A silencing in RA sensitive lines. Quantitative-PCR assays were used to validate the most significant enriched metabolic gene sets and MYCN western blotting was performed at different time points after CHAF1A silencing.

Results. CHAFIA suppression in MYCN-amplified RA-sensitive and RA-resistant lines results in NB differentiation and inhibition of cell proliferation. CHAF1A silencing significantly (nominal p-value <0.05 and FDR q-value <0.25) enriches for cell metabolism pathways (valine, leucine, and isoleucine degradation, glutamate metabolism and insulin pathways) and suppresses pathways with known oncogenic function in neuroblastoma (KRAS, ALK, Akt and BMI1). Q-PCR studies confirmed the regulation by CHAF1A of gene sets regulating glucose and glutamine metabolism. Importantly, MYCN protein levels were profoundly suppressed upon CHAF1A silencing.

Conclusions. We have shown that differentiation of NB cells upon CHAF1A silencing: 1) induces metabolic reprogramming by decreasing glucose and glutamine uptakes, 2) inhibits cell proliferation, and 3) reduces MYCN protein levels. We hypothesize that CHAF1A plays a critical role in the MYCN-mediated metabolic reprogramming of undifferentiated NB tumors. Future studies will further dissect this link and guide the development of novel differentiating therapies for high-risk NB.

Citation Format: Eveline Barbieri, Zaowen Chen, Mirthala Moreno-Smith, Jason M. Shohet. The epigenetic modifier CHAF1A opposes neuroblastoma differentiation via metabolic reprogramming. [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 A02.
Abstract A08: Identification of c-MYC SUMOylation by mass spectrometry
Authors: Kalkat Manpreet , Chan Pak-Kei , Wasylishen Amanda R. , Srikumar Tharan , Kim Sam S. , Ponzielli Romina , Bazett-Jones David P. , Raught Brian , Penn Linda Z.
Published: October 2015

The c-MYC transcription factor is a master regulator of many cellular processes and deregulation of this oncogene has been linked to more than 50% of all cancers. In normal cells, MYC is tightly controlled at a number of steps, including at the transcriptional, translational and post-translational levels. Altered regulation at any of these steps can result in deregulated, oncogenic MYC. One well-studied canonical pathway that is known to regulate MYC activity and stability at the post-translational level is the GSK3 pathway. The GSK3-FBXW7 axis regulates MYC via phosphorylation at T58, followed by ubiquitylation of MYC by the E3 ubiquitin ligase complex SCF-FBXW7 and subsequent proteasomal degradation. Accordingly, substituting threonine 58 with alanine (T58A) confers increased stability and transformative potential. Thus, characterizing the post-translational modifications (PTMs) of MYC can lead to a better understanding of the regulatory mechanisms controlling this potent oncogene. SUMOylation is a post-translational modification that utilizes a series of E1, E2 and E3 proteins for conjugation of a small ubiquitin-like modifier (SUMO) moiety to its target protein. Growing evidence indicates that SUMOylation has many important roles in the cell, such as response to cellular stressors and transcriptional regulation. Moreover, recent reports have unveiled a potential role for SUMOylation in MYC-driven tumourigenesis. Here, using immunoprecipitation combined with mass spectrometry, we identified a MYC SUMOylation site (K326). Abrogation of signaling through this residue by substitution with arginine (K326R) has no obvious effects on MYC half-life, intracellular localization, transcriptional targets, nor on the biological effects of MYC overexpression in three different cell systems assessed for soft agar colony formation, proliferation, and apoptosis. While we have definitively demonstrated that MYC SUMOylation can occur on K326, future work will be needed to elucidate the mechanisms and biological significance of MYC regulation by SUMOylation.

Citation Format: Manpreet Kalkat, Pak-Kei Chan, Amanda R. Wasylishen, Tharan Srikumar, Sam S. Kim, Romina Ponzielli, David P. Bazett-Jones, Brian Raught, Linda Z. Penn. Identification of c-MYC SUMOylation by mass spectrometry. [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 A08.
Abstract A12: Identifying MYC post-translational modifications using a mass spectrometry-based approach
Authors: Resetca Diana , Kalkat Manpreet , Lourenco Corey , Chan Pak-Kei , Srikumar Tharan , Raught Brian , Penn Linda
Published: October 2015

MYC activity is regulated by a complex network of signaling cascades and protein interactions, some of which result in post-translation modifications (PTMs). For example, phosphorylation of the regulatory threonine 58 (T58) and serine 62 (S62) plays a pivotal role in regulating MYC stability and activity. Loss of this regulatory pathway in cancer can lead to MYC dysregulation and contribute to tumorigenesis. Despite their important role, the majority of MYC PTMs arising downstream of different signaling cascades and their consequences on regulating MYC activity remain largely unknown.

To capture the broad spectrum of MYC PTMs, a mass spectrometry (MS)-based approach is being pursued to attain high sequence coverage and enable the identification of PTMs throughout the protein. MYC was overexpressed in the HEK293T cell line, immunoprecipitated, digested, and analyzed on the Velos Orbitrap MS. This analysis facilitated the identification of a range of MYC PTMs, including phosphorylation, sumoylation, ubiquitination and acetylation. Phosphorylation was readily detectable at residues T58 and S62, consistent with previous reports. Additionally, we also observed a previously reported phosphorylation cluster involving residues T343/S344/S347/S348, suggesting that these sites might play a role in regulating MYC function. Indeed, converting these residues to alanine to prevent phosphorylation resulted in a gain-of-function mutant (See Penn Lab poster Lorenco et al.). Another phosphorylation was observed mapping to residues S71 and/or S81. Mutating these sites to alanine also potentiated MYC transformation, highlighting the role of PTMs in regulating MYC function. A MYC sumoylation site was identified on lysine 326 (K326) and is subject of ongoing investigation (See Penn Lab poster Kalkat et al.). Additionally, we will discuss approaches presently underway to increase sequence coverage and identify additional MYC PTMs.

PTMs play an important role in regulating the activity of transcription factors, including that of MYC. Moreover, PTMs can contribute to the dysregulation of its activity in cancer. Thus, mapping the array of PTMs in MYC, understanding their role in regulating MYC function, and elucidating the pathways that converge on these PTMs may pave the way for the development of novel therapeutic strategies aimed at targeting MYC-induced tumorigenesis.

Citation Format: Diana Resetca, Manpreet Kalkat, Corey Lourenco, Pak-Kei Chan, Tharan Srikumar, Brian Raught, Linda Penn. Identifying MYC post-translational modifications using a mass spectrometry-based approach. [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 A12.
Abstract A34: The stress response transcription factor ATF4 mediates cytoprotective pathways in c-Myc overexpressing cells
Authors: Tameire Feven Tameire , Koumenis Costas
Published: October 2015

The proto-oncogene c-Myc is often deregulated in human tumors and its overexpression associates with poor prognosis in patients. While c-Myc is a potent activator of pro-tumorigenic pathways, it can also induce anti-tumorgenic pathways such as apoptosis. However, in c-Myc driven cancers the anti-tumorigenic state is evaded via a yet poorly understood pro-survival mechanism. We previously reported that activation of the PERK arm of the Unfolded Protein Response (UPR) is one such pro-survival mechanism induced by c-Myc to bypass c-Myc induced apoptosis. We also demonstrated enhanced activation of the PERK/p-eIF2α arm of the UPR in a mouse model of lymphoma and in B-cells from human lymphoma patients compared to normal tissues. ATF4, one of the main downstream effectors of PERK, regulates amino acid metabolism, antioxidant response and autophagy. Using the CRISPR/CAS9 genome-editing tool we were able to ablate portions of the ATF4 gene in DLD-1, human colon carcinoma cell line, preventing ATF4 protein expression. Here, we show ATF4 expression is induced in Myc overexpressing ATF4-WT DLD-1 cells. Activation of c-Myc in ATF4-deficient DLD-1 cells resulted in decreased clonogenic survival and reduced autophagy. Addition of Trolox, an antioxidant, conferred protection in ATF4 deficient cells. These findings indicate that the transcription factor ATF4 activates pro-survival pathways such as antioxidant response and autophagy during c-Myc overexpression to promote survival. Therefore, therapeutically targeting these pathways would switch the balance towards cell death in c-Myc dependent tumors.

Citation Format: Feven Tameire Tameire, Costas Koumenis. The stress response transcription factor ATF4 mediates cytoprotective pathways in c-Myc overexpressing 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 A34.
Abstract A36: Interaction of the MYC oncoprotein with the tumor suppressive SWI/SNF complex member INI1
Authors: Tu William B. , Stojanova Angelina , Ponzielli Romina , Kotlyar Max , Chan Pak-Kei , Boutros Paul C. , Khosravi Fereshteh , Jurisica Igor , Raught Brian , Penn Linda Z.
Published: October 2015

The MYC oncogene is a key driver of cellular transformation that is deregulated in more than half of all human cancers. The transcriptional regulatory function of MYC and the wide spectrum of biological processes it mediates are critically tied to its chromatin interactors and epigenetic context. MYC is linked to chromatin remodeling through its interaction with INI1 (SMARCB1/hSNF5/BAF47), a core member of the SWI/SNF complex and a potent tumour suppressor. Recent sequencing efforts in many cancer types also identified frequent mutations in other members of this complex. However, the mechanistic understanding of the SWI/SNF complex in contributing to oncogenesis and its functional and molecular interaction with MYC remain unclear. Herein, we provide a comprehensive characterization of the MYC-INI1 interaction. We demonstrate their direct interaction and extensively delineate their minimal regions of interaction, corresponding to functionally important regions of MYC (leucine zipper) and INI1 (Repeats I and II). Genome-wide analysis reveals that INI1 and other SWI/SNF complex members share significant portions of MYC DNA-binding regions and target genes. Network analysis demonstrates MYC interaction with the SWI/SNF complex and an extended network of shared interactors belonging to additional chromatin regulatory complexes. Collectively, our findings provide significant insight into the interaction of MYC and INI1 at the level of protein-protein and protein-chromatin interactions.

Citation Format: William B. Tu, Angelina Stojanova, Romina Ponzielli, Max Kotlyar, Pak-Kei Chan, Paul C. Boutros, Fereshteh Khosravi, Igor Jurisica, Brian Raught, Linda Z. Penn. Interaction of the MYC oncoprotein with the tumor suppressive SWI/SNF complex member INI1. [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 A36.
Abstract A42: In vitro and in vivo studies of c-Myc amplifiers function
Authors: Nie Zuqin , Guo Chunhua , Simons Stoney S. , Levens David L.
Published: October 2015

c-Myc, the product of a proto-oncogene Myc originally was identified as a transcriptional factor, which interacts with MAX protein through the basic helix-loop-helix leucine zipper (bHLHZip) domain and binds to the DNA containing the E-box (CACGTG) to regulate global gene expression. Recently, we and others found that c-Myc is a genome-wide non-linear amplifier of all expressed genes. The purpose of this study is to confirm previous results that c-Myc targets active promoters and enhancers to amplify the gene expression and to define the contributions of different Myc boxes (Mbs) in the regulation of gene expression and to identify the protein partners of Mbs.

A Gibson Assembly system was used to create the A to N mutations of conserved amino acids in different Mbs. The wild type (WT) and mutated Myc –Pd4-EGFP fusion genes were transiently co-transfected to U2OS cells with Tk-, GRE-TK-, PR-TK-Luc vectors and analyze the reporter activities with a Dual-Luciferase Reporter Assay System, respectively. Our preliminary data demonstrated that WT-c-Myc does amplify reporter gene activity non-linearly. However, constructs with mutatied MbI and MbII were handicapped for amplification. Interestingly, mutated MbIII-b dramatically enhanced reporter gene amplification especially at higher Myc concentrations. Using reporter constructs with and without E-boxes, we found that this element is not necessary to enable c-Myc 's amplification function. To understand c-Myc's function in vivo, we established several Tet-inducible WT and mutated c-Myc stable cell lines with lenti-virus transduced system. The gene expression profiles of these cell lines are being compared. The screening of the partners of different Mb domains is on the way.

Citation Format: Zuqin Nie, Chunhua Guo, Stoney S. Simons, David L. Levens. In vitro and in vivo studies of c-Myc amplifiers function. [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 A42.
Abstract B16: A novel long non-coding RNA connects c-Myc to tumor metabolism
Authors: Wang Ling-Yu , Hung Chiu-Lien , Yu Yen-Ling , Chen Hongwu , Srivastava Shiv , Petrovics Gyorgy , Kung Hsing-Jien
Published: October 2015

Long non-coding RNAs have been implicated in a variety of physiological and pathological processes including cancer. In prostate cancer, PCGEM1 (prostate cancer gene expression marker 1) is an androgen-induced prostate specific lncRNA whose overexpression is highly associated with prostate tumors. PCGEM1's tumorigenic potential was recently shown to be in part due to its ability to activate androgen receptor (AR). Here we report a novel function of PCGEM1 that provides growth advantages for cancer cell by regulating tumor metabolism via c-Myc activation. PCGEM1 promotes glucose uptake for aerobic glycolysis, coupling with pentose phosphate shunt to facilitate biosynthesis of nucleotide and lipid, and generates NADPH for redox homeostasis. We show that PCGEM1 regulates metabolism at the transcriptional level that affects multiple metabolic pathways including glucose and glutamine metabolism, pentose phosphate pathway, nucleotide and fatty acid biosynthesis, and TCA cycle. The PCGEM1-mediated gene regulation takes place in part through AR activation, but predominantly through c-Myc activation regardless of hormone or AR status. Significantly, PCGEM1 binds directly to target promoters, physically interacts with c-Myc, promotes chromatin recruitment of c-Myc, and enhances its transactivation activity. We also identified c-Myc binding domain on PCGEM1 that contributes to the PCGEM1 dependent c-Myc activation and target induction. Together, our data uncover PCGEM1 as a key transcriptional regulator of central metabolic pathways in prostate cancer cell. By being a coactivator for both c-Myc and AR, PCGEM1 reprograms the androgen network and the central metabolism in a tumor specific way, making it a promising target for therapeutic intervention.

Citation Format: Ling-Yu Wang, Chiu-Lien Hung, Yen-Ling Yu, Hongwu Chen, Shiv Srivastava, Gyorgy Petrovics, Hsing-Jien Kung. A novel long non-coding RNA connects c-Myc to tumor metabolism. [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 B16.
Abstract B20: EnCore-LNP mediated tumor delivery of MYC and CTNNB1 Dicer Substrate RNAs (DsiRNAs)
Authors: Abrams Marc , Ganesh Shanthi , Ying Bo , Chopda Girish , Saxena Utsav , Shah Anee , Koser Martin , Arvan Rokhand , Chen Dongyu , Shui Serena , Diwanji Rohan , Zhou Wei , Holmes Benjamin , Kim Boyoung , Yang Hailin , Patel Mihir , Cyr Wendy , Cyr Wendy , Pursell Natalie , Avitahl-Curtis Nicole , Dudek Hank , Lai Cheng , Wang Weimin , Brown Bob D.
Published: October 2015

MYC and CTNNB1 are well-characterized drivers of numerous tumor types. Human and preclinical genetic evidence suggest that pharmacological intervention to reduce transactivation of MYC and CTNNB1-regulated genes would yield therapeutic benefit to many cancer patients. Since the proteins encoded by these genes are challenging to target via conventional modalities, progress in new therapeutic agents has been slow despite decades of research. RNA interference technology has enabled the inhibition of previously-undruggable genetic targets at the mRNA level, and has advanced to clinical development for several indications. DCR-MYC is a Phase I-stage lipid nanoparticle (LNP)-formulated Dicer substrate siRNA (DsiRNA), representing a potent class of RNAi triggers being developed by Dicerna Pharmaceuticals. Here we describe new preclinical data that increase our understanding of the parameters that impact tumor delivery and activity of DsiRNA. We demonstrate that the cationic lipid and PEG-lipid components of Dicerna's unique EnCore LNP platform can be modulated to improve delivery of DsiRNA to both orthotopic and spontaneous liver tumors, as well as xenograft tumors of diverse non-hepatic tissue origin. Characterization of LNP formulations with respect to plasma PK, tissue exposure and target mRNA knockdown was employed towards understanding the pharmacology of LNP-mediated tumor delivery.

Citation Format: Marc Abrams, Shanthi Ganesh, Bo Ying, Girish Chopda, Utsav Saxena, Anee Shah, Martin Koser, Rokhand Arvan, Dongyu Chen, Serena Shui, Rohan Diwanji, Wei Zhou, Benjamin Holmes, Boyoung Kim, Hailin Yang, Mihir Patel, Wendy Cyr, Wendy Cyr, Natalie Pursell, Nicole Avitahl-Curtis, Hank Dudek, Cheng Lai, Weimin Wang, Bob D. Brown. EnCore-LNP mediated tumor delivery of MYC and CTNNB1 Dicer Substrate RNAs (DsiRNAs). [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 B20.
Abstract B23: Pushing Myc inhibition towards the clinic by direct delivery of cell-penetrating peptides
Authors: Beaulieu Marie-Eve , Jauset Toni , Massó-Valles Daniel , Whitfield Jonathan R. , Pozo Erika Serrano del , Tremblay Cynthia , Maltais Loïka , Montagne Martin , Lavigne Pierre , Soucek Laura
Published: October 2015

Inhibiting Myc has long been regarded as a promising cancer treatment. However, clinical Myc inhibition was considered unfeasible due to its central role in normal proliferation and the difficulties of targeting a nuclear transcription factor. The expression of Omomyc (a Myc inhibitor derived from the dimerization and DNA-binding domain of Myc) in the KRasG12D non-small cell lung cancer (NSCLC) mouse model challenged these assumptions, as it resulted in dramatic tumor clearance with only limited and well tolerated side effects in normal tissues (Soucek et al., 2008 and 2013). Omomyc expression proved equally potent in several other mouse models of cancer, revealing the huge potential of this inhibitory approach against multiple cancer types including papilloma, pancreas and glioma (Soucek et al., 2004; Sodir et al., 2011; Annibali et al., 2014). Recently, Max*, a b-HLH-LZ peptide derived from Myc's obligate protein partner Max, was shown to spontaneously enter cells (Montagne et al., 2012). As Omomyc and Max* display high structural homology, we hypothesized that Omomyc could also behave as a cell-penetrating peptide and thus recapitulate the effects of its transgenic counterpart. Our preliminary results show that the Omomyc peptide is well folded in solution; it transduces into cancer cells and effectively stops their proliferation in a dose-dependent manner.In vivo, nasal instillation of fluorescently-labeled Omomyc peptide leads to its rapid distribution to lungs and brain, as well as to other organs (G.I. tract, liver), as observed by IVIS® imaging and immunohistochemistry. Finally, a short treatment with the Omomyc peptide reduces the tumor size and number of Ki67 positive cells in the KRasG12D-induced NSCLC mouse model. In summary, the Omomyc cell penetrating peptide represents a new opportunity to pharmacologically inhibit Myc in a variety of malignant diseases.

Citation Format: Marie-Eve Beaulieu, Toni Jauset, Daniel Massó-Valles, Jonathan R. Whitfield, Erika Serrano del Pozo, Cynthia Tremblay, Loïka Maltais, Martin Montagne, Pierre Lavigne, Laura Soucek. Pushing Myc inhibition towards the clinic by direct delivery of cell-penetrating peptides. [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 B23.
Abstract B26: BET and HDAC inhibitors induce similar genes and biological effects and synergize to kill in Myc-induced murine lymphoma
Authors: Bhadury Joydeep , Nilsson Lisa M. , Somsundar Muralidharan Veppil , Green Lydia C. , Keller Ulrich B. , McLure Kevin G. , Nilsson Jonas A.
Published: October 2015

Bromodomain and extraterminal (BET) proteins bind acetylated proteins, including histones, and regulate transcription. Recently, BET inhibitors (BETi) have been developed that show promise as potent anti-cancer drugs against various solid and hematological malignancies. Here we show that the structurally novel and orally bioavailable BETi RVX2135 inhibits proliferation and induces apoptosis of lymphoma cells arising in Myc-transgenic mice, in vitro and in vivo. We find that BET inhibition exhibited broad transcriptional effects in Myc-transgenic lymphoma cells affecting many transcription factor networks. By examining the genes induced by BETi, which have been largely ignored to date, we discovered that these were similar to those induced by histone deacetylase inhibitors (HDACi). HDACi also induced cell cycle arrest and cell death of Myc-induced murine lymphoma cells and synergized with BETi. To date many of the effects of BETi have been attributed to transcriptional suppression of genes like the MYC oncogene. Moreover, global profiling of the expression of miRNAs demonstrated that HDACi and BETi exhibited a very similar miRNA transcriptome. We also show one of the possible mechanism which might leads to the similarity of induced genes by BETi and HDACi using ChIP-sequencing experiments. Finally, we unravel a genetic and functional link between BET proteins and histone deacetylases (HDAC) that opens up avenues for combination therapies against a variety of cancer.

Citation Format: Joydeep Bhadury, Lisa M. Nilsson, Muralidharan Veppil Somsundar, Lydia C. Green, Ulrich B. Keller, Kevin G. McLure, Jonas A. Nilsson. BET and HDAC inhibitors induce similar genes and biological effects and synergize to kill in Myc-induced murine 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 B26.
Abstract B48: Identification of novel drug interactions with MYC via a quantitative chemical-genetic interaction map
Authors: Zhou Alicia Y. , Martins Maria M. , Corella Alexandra , Horiuchi Dai , Yau Christina , Rakshandehroo Taha , Gordan John D. , Levin Rebecca S. , Johnson Jeff , Jascur John , Shales Mike , Sorrentino Antonio , Cheah Jaime , Clemons Paul A. , Shamji Alykhan , Schreiber Stuart L. , Krogan Nevan J. , Shokat Kevan M. , McCormick Frank , Goga Andrei , Bandyopadhyay Sourav
Published: October 2015

There is an urgent need in oncology to link molecular aberrations in tumors with therapeutics that can be administered in a personalized fashion. One approach identifies synthetic-lethal genetic interactions or emergent dependencies that cancer cells acquire in the presence of specific mutations. Using engineered isogenic cells, we generated an unbiased and quantitative chemical-genetic interaction map that measures the influence of 51 aberrant cancer genes on 90 drug responses. The dataset strongly predicts drug responses found in cancer cell line collections, indicating that isogenic cells can model more complex cellular contexts. Applied to triple-negative breast cancer, we report clinically actionable interactions with the MYC oncogene including resistance to AKT/PI3K pathway inhibitors and an unexpected sensitivity to dasatinib through LYN inhibition in a synthetic-lethal manner, providing new drug and biomarker pairs for clinical investigation. This scalable approach enables the prediction of drug responses from patient data and can be used to accelerate the development of new genotype-directed therapies.

Citation Format: Alicia Y. Zhou, Maria M. Martins, Alexandra Corella, Dai Horiuchi, Christina Yau, Taha Rakshandehroo, John D. Gordan, Rebecca S. Levin, Jeff Johnson, John Jascur, Mike Shales, Antonio Sorrentino, Jaime Cheah, Paul A. Clemons, Alykhan Shamji, Stuart L. Schreiber, Nevan J. Krogan, Kevan M. Shokat, Frank McCormick, Andrei Goga, Sourav Bandyopadhyay. Identification of novel drug interactions with MYC via a quantitative chemical-genetic interaction map. [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 B48.
Abstract IA12: Mechanisms of MYC addiction
Authors: Felsher Dean
Published: October 2015

Many human cancers are caused by the activation of the MYC oncogene. We have developed experimental transgenic mouse models to model and predict the therapeutic efficacy of targeted therapy of oncogenes. Using the Tet system, we can conditionally regulate oncogene expression in vivo in a temporally controlled and tissue specific manner. We have shown that many oncogenes (MYC, RAS, BCR-ABL) induce tumorigenesis that is completely reversible upon their inactivation. We have described this phenomenon as oncogene addiction. Oncogene addiction is associated with proliferative arrest, apoptosis, differentiation, cellular senescence and the shutdown of angiogenesis.

The specific consequences of MYC oncogene inactivation depend both on the genetic and cellular context. In some cases, even brief inactivation of an oncogene can result in sustained tumor regression. In other cases, oncogene inactivation is associated with tumor dormancy. Tumor cell intrinsic and host-dependent cell autonomous mechanisms are involved. Tumor cell intrinsic mechanisms appear to involve mechanisms that are dependent upon DNA repair processes, the regulation of protein synthesis and of cellular metabolism. Host-dependent mechanisms include the regulation of angiogenesis and immune cell elimination. In addition, tumor cells secrete autocrine factors critical to oncogene addiction.

We have uncovered that oncogene addiction is both dependent upon cell autonomous and host cell dependent mechanisms. Thus, MYC via miR17-92 regulates chromatin regulatory gene products required to in a cell autonomous manner regulate cellular proliferation, survival and self-renewal programs. However, MYC through regulation of host immune mechanisms and the recruitement of CD4+ T-cells, in a host cell dependent manner, regulates the tumor microenvironment.

Our experimental model systems have been employed to generate nanotechnologies and molecular imaging approaches as well as innovative therapies to respectively predict and to elicit MYC addiction.

Citation Format: Dean Felsher. Mechanisms of MYC addiction. [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 IA12.
Abstract IA20: Reduced expression of MYC increases longevity and enhances healthspan
Authors: Sedivy John M.
Published: October 2015

MYC is a highly pleiotropic transcription factor whose deregulation promotes cancer. We find that Myc haploinsufficient (Myc+/–) mice exhibit increased lifespan. They show resistance to several age-associated pathologies, including osteoporosis, cardiac fibrosis and immunosenescence. They also appear to be more active, with a higher metabolic rate and healthier lipid metabolism. Transcriptomic analysis reveals a gene expression signature enriched for metabolic and immune processes. The ancestral role of MYC as a regulator of ribosome biogenesis is reflected in reduced protein translation, which is inversely correlated with longevity. We also observe changes in nutrient and energy sensing pathways, including reduced serum IGF-1, increased AMPK activity, and decreased AKT, TOR and S6K activities. In contrast to observations in other longevity models, Myc+/– mice do not show improvements in stress management pathways. Our findings indicate that MYC activity has a significant impact on longevity and multiple aspects of mammalian healthspan.

Citation Format: John M. Sedivy. Reduced expression of MYC increases longevity and enhances healthspan. [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 IA20.
Abstract IA27: Inhibition of MYC transcriptional signaling
Authors: Bradner James E.
Published: October 2015

MYC is a master regulator of stem cell state, embryogenesis, tissue homeostasis, and aging. As in health, in disease MYC figures prominently. Decades of biological research have identified a central role for MYC in the pathophysiology of cancer, inflammation and heart disease. The centrality of MYC to such a vast breadth of disease biology has attracted significant attention to the historic challenge of developing inhibitors of MYC. This presentation will discuss therapeutic strategies towards the development of inhibitors of MYC-dependent transcriptional signaling and the elusive goal of developing potent, direct-acting inhibitors of MYC.

Citation Format: James E. Bradner. Inhibition of MYC transcriptional signaling. [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 IA27.
Abstract PR13: miR-17-92 mediates MYC oncogene addiction
Authors: Li Yulin , Choi Peter S. , Casey Stephanie C. , Dill David L. , Felsher Dean W.
Published: October 2015

The MYC oncogene is frequently overexpressed in human cancers. MYC can transcriptionally and translationally regulate the expression of thousands of genes. However, it was unclear which specific genes are responsible for MYC to maintain a neoplastic state. The microRNA cluster miR-17-92 is a major MYC target gene known to regulate proliferation, survival, and angiogenesis, which are several of the key phenotypes associated with MYC oncogene addiction. The resemblance of biological functions between MYC and miR-17-92 thus evoked the hypothesis that miR-17-92 is causally responsible for at least part of the mechanism by which MYC maintains a neoplastic state. We have found that miR-17-92 regulates multiple histone modifiers, such as Sin3b, Hbp1, Suv420h1, and Btg1, as well as the apoptosis regulator Bim, to maintain autonomous proliferation, survival, and self-renewal of MYC-driven tumors. Conversely, MYC inactivation downregulates the expression of miR-17-92 and results in the loss of neoplastic features as a consequence of restoration of senescence, apoptosis, and differentiation. Thus, the expression of miR-17-92 can dictate the cellular fates of MYC-driven tumors between survival versus apoptosis and proliferation versus senescence. Our findings provide a mechanistic insight into why tumors are dependent on or addicted to MYC.

Citation Format: Yulin Li, Peter S. Choi, Stephanie C. Casey, David L. Dill, Dean W. Felsher. miR-17-92 mediates MYC oncogene addiction. [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 PR13.
Abstract PR14: HIF-2alpha regulates self-renewal of MYC dependent cancer stem cells
Authors: Das Bikul , Das Bikul , Li Hong , Li Hong , Bhuyan Rashmi , Felsher Dean W.
Published: October 2015

Numerous studies report that both hematopoietic and some solid tumors are organized in a hierarchical manner where tumor growth is driven by a small subset of cancer stem cells (CSCs). However, the distinct molecular identity of CSC versus non-CSC is not yet clearly known, which limit our understanding on how CSC self-renewal pathways operate to drive tumorigenicity. Here, we report that MYC and HIF-2alpha co-operate to maintain distinct identity and self-renewal capacity of CSCs. In a transgenic mouse model of conditional MYC driven thymic lymphoma, we identified a Sca-1+ cell population that showed tumor stemness (self-renewal and undifferentiation state) phenotype, including high expression of Nanog, Sox2 and HIF-2alpha. When injected to congenic mice, Sca-1+ cells but not Sca-1- cells exhibited hierarchical organization including self-renewal capacity. ChIP assay revealed direct MYC binding of HIF-2alpha promoter region in Sca-1+ but not in the Sca-1- cells. Inhibition of HIF-2alpha led to increase ROS generation, decrease of GSH synthesis, differentiation, and loss of self-renewal capacity of Sca-1+ cells. In contrast, inhibition of HIF-2alpha had no phenotypic effect on Sca-1- cells. Thus, we have identified a distinct CSC population in MYC dependent cancer cells, where MYC preferentially binds to HIF-2alpha to maintain self-renewal capacity.

Citation Format: Bikul Das, Bikul Das, Hong Li, Hong Li, Rashmi Bhuyan, Dean W. Felsher. HIF-2alpha regulates self-renewal of MYC dependent cancer 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 PR14.
Abstract A04: Systemic agonistic anti-CD40 treatment of tumor bearing mice modulates hepatic myeloid suppressive cells and causes immune-mediated liver damage
Authors: Medina-Echeverz Jose , Ma Chi , Eggert Tobias , Greten Tim F.
Published: October 2015

Immune stimulatory monoclonal antibodies are currently evaluated as antitumor agents in clinical trials. Although overall toxicity appears to be moderate, liver toxicities have been reported and are not completely understood. Therefore, we decided to study the effect of systemic CD40 antibody treatment on the liver immune microenvironment. Agonistic CD40 antibody or isotype control was injected intraperitoneally into naïve and tumor-bearing mice. Liver enzymes, histologies and immune infiltrates were analyzed after antibody administration. The effect of agonistic CD40 administration was evaluated using bone marrow chimeras and genetically modified mouse strains Cd40-/- and Nox2-/-. Mouse and human tumor-induced myeloid suppressive cells were cultured to address changes in their immune function upon CD40 ligation. Agonistic CD40 antibody caused liver damage within 24 hours after injection in two unrelated tumor models and mice strains. Using bone marrow chimeras we could demonstrate that CD40 antibody-induced hepatitis in tumor-bearing mice was dependent on the presence of CD40+ immune cells. Agonistic CD40 ligation-dependent liver damage was induced by the generation of reactive oxygen species. Furthermore, agonistic CD40 antibody resulted in increased CD80 and CD40 positive liver CD11b+Gr-1+ immature myeloid cells. CD40 ligation on tumor-induced hepatic myeloid cells or CD14+HLA-DRlow PBMC from cancer patients reduced their immune suppressor function. Collectively, agonistic CD40 antibody activates the tumor-induced liver myeloid suppressive compartment, enhancing acute inflammation and thus liver damage. Our data in murine and human myeloid suppressive cells point towards a pivotal role for CD40 as a key molecule in modulating myeloid suppressive cell plasticity.

Citation Format: Jose Medina-Echeverz, Chi Ma, Tobias Eggert, Tim F. Greten. Systemic agonistic anti-CD40 treatment of tumor bearing mice modulates hepatic myeloid suppressive cells and causes immune-mediated liver damage. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy: A New Chapter; December 1-4, 2014; Orlando, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2015;3(10 Suppl):Abstract nr A04.
Abstract A28: TRAIL mediated reduction of an immunogenic cell death protein, heat shock protein 70, in glioblastoma
Authors: McCray Andrea N.
Published: October 2015

There are various Damage-Associated Molecular Patterns (DAMPs) that are recognizable by the immune system in the cancer microenvironment. DAMPs are revealed under a specific type of cell death termed immunogenic cell death in which stimuli force the cancer cells to die and leave antigen traces such as heat shock proteins that can be used against the disease. The stimulus of interest in this study was recombinant human Tumor-necrosis factor-related apoptosis-inducing ligand (TRAIL) which was known to selectively kill cancer cells such as glioblastoma cells. This study examined the role of TRAIL in immunogenic cell death for brain cancer. High density T98G glioblastoma cells were cultured with or without 50 ng/ml recombinant human TRAIL for four days. The trypan blue exclusion assay revealed that the average death rate for the TRAIL treated glioblastoma cells was 42%. Furthermore, western blot analysis showed that TRAIL treated cells had a reduction in heat shock protein 70 expression. Previous studies in the literature showed heat shock protein 70 mediated apoptosis resistance in cancer cells. The current study suggests that, even in the absence of any other inhibitors, heat shock protein 70 down-regulation via TRAIL may cause the chemoresistant glioblastoma cells to become susceptible to TRAIL-mediated cell death. Future studies will further investigate the relationship between DAMPs and TRAIL and the extent to which TRAIL generates sufficient apoptotic glioblastoma cells that would serve as the antigenic source for T cell immunotherapy regimens.

Disclaimer: This research was supported in part by the James A. Haley Veterans' Hospital. The contents of this publication do not represent the views of the Department of Veterans Affairs or the United States Government.

Citation Format: Andrea N. McCray. TRAIL mediated reduction of an immunogenic cell death protein, heat shock protein 70, in glioblastoma. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy: A New Chapter; December 1-4, 2014; Orlando, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2015;3(10 Suppl):Abstract nr A28.