bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract A20: Excess centrosomes induce p53-dependent senescence in endothelial cells
Authors: Yu Zhixian , Kushner Erich , Bautch Victoria 
Published: November 2016

Abstract
Excess centrosomes (&gt;2 centrosomes/cell), which are prevalent in both tumor cells and tumor endothelial cells, lead to aneuploidy and chromosome instability. Therefore, understanding how excess centrosomes affect cell behaviors is critical for studying tumor progression and tumor angiogenesis. As demonstrated by previous literature, cells with excess centrosomes routinely undergo bipolar cell division to produce viable progeny. However, we found that endothelial cells were not able to maintain the percentage of cells with excess centrosomes, suggesting that excess centrosomes had a negative impact on endothelial cell cycle. We used a tetracycline-inducible Polo-like kinase 4 (Plk4)-expressing system to induce excess centrosomes in human umbilical vein endothelial cells (HUVEC). Doxycycline treatment induced ~30% centrosome over-duplication, which decreased to &lt;5% in 6 days. We found that HUVEC with excess centrosomes activated p53 by phosphorylating p53 at Ser33. Complete down-regulation of p53 helped maintain the frequency of cells with excess centrosomes. Excess centrosomes-induced p53 activation was independent of DNA damage, as demonstrated by lack of p53 Ser15 phosphorylation or γH2AX foci. Excess centrosomes induced senescence but not apoptosis, as shown by senescence-associated beta-galactosidase (SA-β-gal) activity and Galactosidase Beta 1 (GLB1) antibody staining, and the induced senescence can be blocked by p53 down-regulation. Since endothelial cells maintain different cell shapes and behavior in a 3-dimensional (3D) environment compared to 2D, we asked whether excess centrosomes induce senescence in 3D. We used a sprouting angiogenesis assay and found that centrosome over-duplicated ECs in 3D sprouts showed SA-β-gal activity, suggesting that they underwent senescence. In summary, we show that excess centrosomes induced p53-dependent senescence in endothelial cells in both 2D and 3D. Our work provides a novel association between excess centrosomes and senescence, which will help to better understand regulation of the tumor microenvironment.
Citation Format: Zhixian Yu, Erich Kushner, Victoria Bautch. Excess centrosomes induce p53-dependent senescence in endothelial cells. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Cancer Cell Cycle - Tumor Progression and Therapeutic Response; Feb 28-Mar 2, 2016; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(11_Suppl):Abstract nr A20.
Abstract A30: The effects of Berberis vulgaris on bacterial inhibition and the p53 gene in cancerous Caenorhabditis elegans
Authors: Bhatt Jesal P. 
Published: November 2016

Abstract
Recently, there has been an interest in the use of natural products to inhibit bacterial growth rather than manufactured antibiotics due to the problem of bacterial resistance. This study aims at finding the most effective natural antibacterial remedy. The disk diffusion method was used to compare the antibacterial properties of manuka honey, barberry, aloe vera, and colloidal silver. After a 48-hour incubation period, the zone of inhibition was measured for the following bacteria: Bacillus megaterium, Serratia marcescens, Pseudomonas fluorescens, Rhodospirillum rubrum, and Escherichia coli. Barberry was the most efficient natural product (p=0.02). Further tests were performed to determine whether barberry contained strong anticancer properties. Barberry was tested on Caenorhabditis elegans (C.elegans), strain JR1279, exposed to ultraviolet-C radiation and the population was counted daily. Prior to this experiment, barberry had never before been tested on a model organism. The purpose of this experiment would determine if barberry could increase the lifespan of the C.elegans by the addition of this reagent. It was shown that the C.elegans exposed to barberry had a longer lifespan than those that were not exposed to barberry (p=0.01), indicating that barberry could be a potential anticancer cancer supplement.
Citation Format: Jesal P. Bhatt. The effects of Berberis vulgaris on bacterial inhibition and the p53 gene in cancerous Caenorhabditis elegans. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Cancer Cell Cycle - Tumor Progression and Therapeutic Response; Feb 28-Mar 2, 2016; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(11_Suppl):Abstract nr A30.
Abstract A31: Reprimo, a potential tumor suppressor gene TP53-dependent, modulates negatively cell migration and invasion in the MDA-MB-231 breast cancer cell line
Authors: Buchegger Kurt , Viscarra Tamara , Ili Carmen Gloria , Riquelme Ismael , Letelier Pablo , Corvalan Alejandro , Brebi Priscilla , Huang Tim Hui-Ming , Roa Juan Carlos 
Published: November 2016

Abstract
Background: Reprimo, a highly glycosylated protein, is a new downstream effector of p53-induced cell cycle arrest at the G2/M checkpoint, and a putative tumor suppressor gene frequently silenced via methylation of its promoter region in several malignances. The aim of this study was to characterize the epigenetic inactivation and its biological function in BC cell lines.
Methods: The correlation between Reprimo methylation and loss of mRNA expression was assessed in six breast cancer cell lines by methylation specific PCR (MSP), 5-Aza-2′-deoxycytidine treatment and qRT-PCR assays. MDA-MB-231 cells were chosen to investigate the phenotypic effect of Reprimo in cell proliferation, cell cycle, cell death, cell migration and invasion.
Results: In the cancer methylome system (CMS) (web-based system for visualizing and analyzing genome-wide methylation data of human cancers), the CpG island region of RPRM (1,1Kb) was hypermethylated in breast cancer compared to normal breast tissue. Downregulation of RPRM mRNA by methylation was confirmed in MDA-MB-231 and BT-20 cell lines. In addition, overexpression of RPRM in MDA-MB-231 cells resulted in decreased rates of cell migration, wound healing and invasion in vitro (P &lt; 0.0001). However, RPRM overexpression did not alter cell viability, rate of death cell and G2/M cell cycle transition in this biological model.
Conclusion: Taken together, these data suggest that RPRM is involved in decreased cell migration and invasion in vitro, acting as a potential tumor suppressor gene in the MDA-MB-231 cell line.
Citation Format: Kurt Buchegger, Tamara Viscarra, Carmen Gloria Ili, Ismael Riquelme, Pablo Letelier, Alejandro Corvalan, Priscilla Brebi, Tim Hui-Ming Huang, Juan Carlos Roa. Reprimo, a potential tumor suppressor gene TP53-dependent, modulates negatively cell migration and invasion in the MDA-MB-231 breast cancer cell line. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Cancer Cell Cycle - Tumor Progression and Therapeutic Response; Feb 28-Mar 2, 2016; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(11_Suppl):Abstract nr A31.
Abstract A33: Biomarkers of Cdk5 driven neuroendocrine tumors
Authors: Carter Angela M. , Telange Rahul , Oltmann Sarah , Nwariaku Fiemu , Robinson Bruce , Grubbs Elizabeth , Bibb James 
Published: November 2016

Abstract
Background: Neuroendocrine (NE) cancers originate from secretory cells of the body's various endocrine structures. Surgical resection is the primary treatment for these tumors. However, the majority of NE cancers are metastatic at the time of detection and no effective adjuvant therapies exist for primary NE tumors or their metastases. Patients often develop two or more NE cancers, a syndrome termed multiple endocrine neoplasia (MEN). DNA sequencing has lead to breakthroughs in the identification of genes mutated in four types of familial MEN syndromes: Menin, RET, and CDNK1B. Unfortunately, a large percentage of NE cancers are sporadic, resulting from somatic mutations, and a high percentage of these do not harbor menin, RET, or CDNK1B mutations. Our lab has determined that Cdk5 promotes growth in multiple types of NE cancer. Phosphoproteomic studies revealed a selective set of proteins potentially phosphorylated downstream of Cdk5 activation. We hypothesize that these phosphoproteins will serve as biomarkers to identify tumors that will be responsive to anti-Cdk5 therapies.
Methods: Phosphorylation state-specific antibodies were generated to novel phosphoprotein sites by inoculation of New Zealand White rabbits with phosphopeptides specific to each site. Antibodies were isolated from rabbit sera by affinity purification using phosphopeptide columns. Human NE cell lines were treated with Cdk5 inhibitors and monitored for effects on phosphoprotein levels. Phosphoprotein levels were examined in growing and arrested medullary thyroid carcinoma tumors isolated from an inducible/arrestable (NSE-tTA; tetO-p25GFP) mouse model and in normal lung versus small cell lung cancer tumors isolated from a triple conditional knockout (p130 f/f; p53 f/f; Rb f/f) mouse model. Phosphoprotein levels were examined in control tissue and human medullary thyroid carcinoma, gastrointestinal NETs, and pancreatic NETs.
Results: Phosphorylation state-specific antibodies were successfully generated to 10 novel phosphoproteins. Cdk5 inhibition decreases phosphorylation levels of 5 of these 10 proteins in several types of NE cell lines. Levels of 4 of these phosphoproteins are elevated in human NE tumors.
Conclusion: Four novel phosphoproteins downstream of Cdk5 comprise a set of biomarkers for Cdk5-dependent human NE tumors. The combination of these biomarkers with pathway specific therapies currently under development will constitute a coupled diagnostic-therapeutic regimen for personalized treatment of NE cancer patients.
Citation Format: Angela M. Carter, Rahul Telange, Sarah Oltmann, Fiemu Nwariaku, Bruce Robinson, Elizabeth Grubbs, James Bibb. Biomarkers of Cdk5 driven neuroendocrine tumors. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Cancer Cell Cycle - Tumor Progression and Therapeutic Response; Feb 28-Mar 2, 2016; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(11_Suppl):Abstract nr A33.
Abstract B08: Retinoblastoma protein orchestrates cellular apoptosis in non-small cell lung cancer in response to CDK4/6 inhibition: novel targets and key mechanisms
Authors: Thangavel Chellappagounder , Boopathi Ettickan , Liu Yi , Haber Alex , Perepelyuk Maryna , Addya Sankar , Shoyele Sunday , Dicker Adam P. , Knudsen Karen E. , Den Robert B. 
Published: November 2016

Abstract
Introduction: The retinoblastoma tumor suppressor protein (RB) is a critical mediator of cell proliferation via its regulation of cell cycle by binding to E2Fs. One of the mechanisms of RB activation is through CDK4/6 inhibition. Currently, multiple selective CDK4/6 inhibitors are being utilized in the clinical setting and are thought to drive cellular cytostasis. In this study, we demonstrate that RB activation not only results in cellular senescence, but for the first time, induces apoptosis by repressing IAPs (inhibitor of apoptosis protein).
Experimental Procedures: Isogenic pairs of RB knockdown and control cells were interrogated in vitro, and in xenograft tumors for CDK 4/6 inhibitor response. Cellular senescence and apoptosis were quantified. Molecular mechanism was determined using microarray, chromatin immunoprecipitation, and co-immunoprecipitation assays.
Summary: CDK4/6 inhibition diminished cell growth in an RB dependent manner both in in vitro and in vivo models. Immunohistochemistry from the xenografts demonstrated increased levels of apoptosis in the RB proficient isogenic lines. This was confirmed via western blot analysis for Caspase-3. Mechanistically, microarray analysis demonstrated that RB activation downregulated several key anti-apoptotic proteins (e.g. FOXM1, Survivin). ChIP assay and in silico modeling showed that FOXM1 and Survivin are repressed by RB/E2F binding. In the RB deficient setting, immunoprecipitation demonstrates that FOXM1 and Survivin interact directly with Caspase-3 resulting in decreased apoptosis. This was reversed using a competitive assay with overexpression of the SMAC (second mitochondrial) protein.
Conclusion: Data from multiple isogenic NSCLC models demonstrate that RB activation via CDK4/6 inhibitors results in apoptosis in an RB dependent manner. Mechanistically, RB represses transcription of multiple IAPs (including FOXM1 and Survivin), which allows pro-apoptotic factors such as SMAC to activate Caspase-3. These findings suggest that CDK4/6 inhibitors should be viewed as cytotoxic, as opposed to purely cytostatic, agents and warrant further clinical investigation.
Citation Format: Chellappagounder Thangavel, Ettickan Boopathi, Yi Liu, Alex Haber, Maryna Perepelyuk, Sankar Addya, Sunday Shoyele, Adam P. Dicker, Karen E. Knudsen, Robert B. Den. Retinoblastoma protein orchestrates cellular apoptosis in non-small cell lung cancer in response to CDK4/6 inhibition: novel targets and key mechanisms. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Cancer Cell Cycle - Tumor Progression and Therapeutic Response; Feb 28-Mar 2, 2016; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(11_Suppl):Abstract nr B08.
Abstract B11: Re-wired E2F function in response to RB loss as a potential driver of castration-resistant prostate cancer
Authors: Mandigo Amy C. , McNair Chris , Schiewer Matthew J. , Xu Kexin , Li Fugen , Myles Brown , Knudsen Karen E. 
Published: November 2016

Abstract
Prostate cancer (PCa) is the most frequently diagnosed non-cutaneous malignancy, and second leading cause of cancer death in males in the United States, causing over 30,000 deaths per year. A crucial component to the development and progression of PCa is the activity of the androgen receptor (AR). AR promotes proliferation and is required for PCa cell growth and survival. As such, targeting the AR-signaling axis through androgen deprivation therapy (ADT) is the first line of therapy for PCa. However, cells invariably become resistant to this therapy and men relapse with the incurable form of the disease, castration-resistant prostate cancer (CRPC). It has been shown that an underlying mechanism of this resistance revolves around the retinoblastoma (RB) tumor suppressor protein. RB functions to repress tumor development by negatively regulating the activity of the E2F family of transcription factors thus, resulting in a decrease in AR levels. RB additionally controls cell cycle progression through its ability to bind and inhibit E2F1 mediated transcription of genes required for G1/S progression. Surprisingly, genome-wide assessment of E2F activity in the absence of RB has been understudied. To better understand the molecular pathways that are altered upon RB loss and the roles they play in CRPC, RNA-Seq and ChIP-Seq analyses were performed in isogenic RB cell lines in both hormone sensitive and CRPC models. Data to be discussed reveal new insight into the differential effects of RB loss on AR and E2F1 function and role as potential drivers of late stage disease.
Citation Format: Amy C. Mandigo, Chris McNair, Matthew J. Schiewer, Kexin Xu, Fugen Li, Brown Myles, Karen E. Knudsen. Re-wired E2F function in response to RB loss as a potential driver of castration-resistant prostate cancer. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Cancer Cell Cycle - Tumor Progression and Therapeutic Response; Feb 28-Mar 2, 2016; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(11_Suppl):Abstract nr B11.
Abstract B27: Kinetochore-microtubule attachments as a precision therapy target
Authors: Herman Jacob A. , Paddison Patrick J. , DeLuca Jennifer , Olson James 
Published: November 2016

Abstract
Glioblastoma multiforme (GBM) is an aggressive and refractory cancer with limited therapeutic strategies and poor survival. One challenge in treating this disease is the ability of single glioblastoma stem-like cells (GSCs) to initiate tumors. To expand the therapeutic repertoire for GBM we performed RNAi screening in GSCs and a proposed cell of origin, neural crest stem cells (NSCs). In these screens we identified multiple regulators of kinetochore-microtubule attachments as specifically required for GSC survival. Kinetochores are composed of hundreds of proteins that form dynamic attachments between microtubules and chromosomes and are essential for genetic fidelity. Antimitotic agents, including those that target kinetochore proteins, are attractive therapeutics because cell division is essential for tumor expansion, but also because mitotic errors can trigger p53-independent apoptotic signals. However, as mitosis is an essential process, most antimitotic drugs have extremely limited therapeutic windows. We demonstrate that specific activities of the mitotic pseudokinase BubR1 are completely dispensable for non-transformed cells, yet become required for survival in a subset of GBM tumors. Through mutational studies we demonstrate that inactivating either BubR1's GLEBS or KARD domain causes lethal chromosome alignment defects in most GSCs and has no observable on-target toxicity in non-transformed cells. We further demonstrate that this cancer-specific requirement arises from oncogenic activation of the MAP kinase pathway, which ultimately hyperactivates Aurora B kinase at kinetochores. Increased phosphorylation of kinetochore proteins weakens their binding to microtubules and can be indirectly measured by a decrease in the distance between sister kinetochore pairs upon microtubule attachment. In limited samples, this measure serves as a functional biomarker for samples that require BubR1 for chromosome alignment. This work has identified multiple precision targets for GBM with dramatic therapeutic windows; moreover, we have initiated development of a biomarker to identify patients that would respond to such a therapy.
Citation Format: Jacob A. Herman, Patrick J. Paddison, Jennifer DeLuca, James Olson. Kinetochore-microtubule attachments as a precision therapy target. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Cancer Cell Cycle - Tumor Progression and Therapeutic Response; Feb 28-Mar 2, 2016; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(11_Suppl):Abstract nr B27.
Abstract B34: Inhibition of breast cancer cell metastasis with a non-cyclooxygenase inhibitory derivative of sulindac by suppressing TGFbeta/miR-21 signaling
Authors: Yi Bin , Chang Hong , Feng Xiangling , Ma Ruixia , Piazza Gary A , Xi Yaguang 
Published: November 2016

Abstract
Compelling efficacy on intervention of tumor occurrence and progression by nonsteroidal anti-inflammatory drugs (NSAIDs) has been intensively reported in numerous preclinical and clinical studies. However, the toxicities related to cyclooxygenase (COX) inhibition resulting in suppression of physiologically important prostaglandins limit their clinical use for human cancer chemoprevention. A novel derivative of the NSAID, sulindac sulfide (SS), referred as sulindac sulfide amide (SSA) was recently developed, which lacks COX inhibitory activity, yet shows greater suppressive effect than SS on growth of variable cancer cells. In this study, we focus on the inhibitory activity of SSA on breast tumor cell motility, which has not been studied previously. Our results showed that SSA could inhibit breast tumor cell invasion and migration at sub-cytotoxic concentrations; whereas we previously reported that SS has similar activity on breast and colon tumor cells but at a concentration (50 µM) over 10 times higher than SSA (4 µM). We found that miR-21, a well-documented oncogenic miRNA for promoting tumor cell metastasis, could be downregulated by SSA and involved in mediation of anti-invasive activity of SSA in breast tumor cells. When studying the mechanisms responsible for the regulation of miR-21 by SSA, we demonstrated that TGFbeta signaling suppressed by SSA could ultimately result in downregulation of miR-21 through the transcriptional control. Reduction of Smad2 and Smad3 phosphorylation was the direct response to SSA treatment in metastatic breast tumor MDA-MB-231 cells. By using ChIP assay, we demonstrated that phosphorylated Smad2/3 could bind to the promoter of miR-21 gene. Therefore, in this project, we demonstrate that a non-COX inhibitory derivative of sulindac can inhibit breast tumor metastasis through a new mechanism involving the TGFbeta/miR-21 signaling axis. This study is supported by the NIH/NCI R01 Grant (1R01CA192395) and the American Cancer Society Research Scholar Grant (RSG-13-265-01-RMC).
Citation Format: Bin Yi, Hong Chang, Xiangling Feng, Ruixia Ma, Gary A Piazza, Yaguang Xi. Inhibition of breast cancer cell metastasis with a non-cyclooxygenase inhibitory derivative of sulindac by suppressing TGFbeta/miR-21 signaling. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Cancer Cell Cycle - Tumor Progression and Therapeutic Response; Feb 28-Mar 2, 2016; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(11_Suppl):Abstract nr B34.
Abstract IA15: The consequences of pRb inactivation: insights from a proteomic analysis of Rb loss
Authors: Nicolay Brandon N. , Danielian Paul S. , Kottakis Filippos , Lapek John D. , Sanidas Ioannis , Miles Wayne O. , Dehnad Mantre , Tschöp Katrin , Gierut Jessica J. , Manning Amity L. , Morris Robert , Haigis Kevin , Bardeesy Nabeel , Lees Jacqueline A. , Haas Wilhelm , Dyson Nicholas J. 
Published: November 2016

Abstract
The retinoblastoma tumor suppressor protein associates with chromatin and regulates gene expression. The transcriptional signatures associated with RB1/Rb mutation are thought to give a picture of the cellular changes that occur when pRB is lost. We used proteomic profiling to examine the changes caused by the ablation of Rb in mouse lung and colon tissues, and compared these with transcript profiles. While the transcription of classic E2F target genes increased similarly in Rbko lung and colon, effects on protein levels were context-dependent. Proteomic changes were identified that were similar between Rb-mutant tissues but, unexpectedly, the major feature of these changes was a decrease in proteins that function in mitochondria. Consistent with this, mutation of RB1 in cultured human cells reduced the number of mitochondrial number and caused mitochondrial dysfunction. Rbko cells had reduced oxygen consumption rate, reduced reserve capacity, an accumulation of depolarized mitochondria and displayed an altered flux of Carbon through the TCA cycle that was evident both in vivo and in vitro. These defects impair cell proliferation under conditions of mitochondria stress. Collectively, these results suggest that the most consistent changes in the proteome of Rbko tissues may not stem from changes in the levels of cell proliferation proteins, but from changes in mitochondrial function. Analysis of transcripts that are induced in Rbko tissues without a corresponding change in protein levels suggests that there may be a mechanism of post-transcriptional control that coordinately suppresses E2F-induced mRNAs.
Citation Format: Brandon N. Nicolay, Paul S. Danielian, Filippos Kottakis, John D. Lapek, Jr., Ioannis Sanidas, Wayne O. Miles, Mantre Dehnad, Katrin Tschöp, Jessica J. Gierut, Amity L. Manning, Robert Morris, Kevin Haigis, Nabeel Bardeesy, Jacqueline A. Lees, Wilhelm Haas, Nicholas J. Dyson. The consequences of pRb inactivation: insights from a proteomic analysis of Rb loss. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Cancer Cell Cycle - Tumor Progression and Therapeutic Response; Feb 28-Mar 2, 2016; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(11_Suppl):Abstract nr IA15.