bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 867: EGFR kinase domain duplication (EGFR-KDD) is activated by asymmetric intra-molecular dimerization
Authors: Du Zhenfang , Gallant Jean-Nicolas , Red-Brewer Monica , Brown Benjamin , Sheehan Jonathan , Meiler Jens , Lovly Christine M. 
Published: August 2019

Abstract
Recently, we identified a novel oncogenic EGFR exon 18 - 25 Kinase Domain Duplication (EGFR-KDD) in patients with lung cancer (PMID: 26286086). This novel EGFR alteration contains two tandem, in-frame EGFR TKDs. Computational modeling suggested that the linker between the two TKDs may support the formation of an asymmetric intra-molecular dimer. In this study, we sought to provide experimental support for the model that EGFR-KDD could form ligand-independent asymmetric intra-molecular dimers. We constructed point mutations (Table 1) disrupting the potential intra- (C1, N2) and inter-molecular dimer interfaces (N1 and C2) between each TKD of EGFR-KDD. We also introduced catalytically inactivating mutation into each TKD individually (Dead1 and Dead2). We stably expressed these mutants in YAMC and NR6, two cell lines lacking endogenous wild-type EGFR expression. In the absence of ligand, ‘wild-type’ EGFR-KDD was phosphorylated on known EGFR auto-phosphorylation sites, Y992, Y1068, and Y1173. However, mutations of the intra-molecular dimer interface (C1, N2) abrogated EGFR-KDD auto-phosphorylation, which is an accepted surrogate for EGFR enzymatic activity. In support of these data, expression of EGFR-KDD, but not the intra-molecular dimer interface mutants (C1, N2), supported growth in soft agar, an assay utilized in support of oncogenic phenotypes. Interestingly, phosphorylation of the dimer interface mutants (C1, N2) was rescued by ligand stimulation, suggesting the formation of EGFR-KDD multimers. Our structural modeling by Rosetta suggests that EGFR-KDD can form high order multimers with itself or with wild-type EGFR, and we observed co-precipitation of EGFR-KDD with itself and wild-type EGFR in vitro. Collectively, our findings define a previously unrecognized model of asymmetric intra-molecular dimers for EGFR, which provides important insights for the understanding of EGFR activation mechanisms and shed light on the exploration of therapeutic benefit.
Table 1:Kinase domain mutations constructed for these studiesLobeMutationFunctionsN1I706QDisruption of the 1st N-lobe interfaceDead1D837NKinase dead mutation of the 1st kinase domainC1V948RDisruption of the 1st C-lobe interfaceN2I1057QDisruption of the 2nd N-lobe interfaceDead2D1188NKinase dead mutation of the 2nd kinase domainC2V1299RDisruption of the 2nd C-lobe interface
Citation Format: Zhenfang Du, Jean-Nicolas Gallant, Monica Red-Brewer, Benjamin Brown, Jonathan Sheehan, Jens Meiler, Christine M. Lovly. EGFR kinase domain duplication (EGFR-KDD) is activated by asymmetric intra-molecular dimerization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 867.
Abstract 879: Nicotine-induced oxidative stress causes epigenetic alterations during malignant transformation of human kidney epithelial cells
Authors: Chang Yuwei , Singh Kamaleshwar 
Published: August 2019

Abstract
Nicotine is a component of cigarette smoke and mounting evidence implicates tobacco smoking in kidney cancer development. Whether nicotine alone can cause kidney cancer is not clear. Moreover, the underlying molecular mechanisms for nicotine-induced carcinogenesis is still not well-understood. Therefore, the objective of this study was to determine if chronic exposure to nicotine results in malignant transformation of HK-2 kidney epithelial cells. The data revealed that chronic exposure to nicotine induced growth and malignant transformation in HK-2 cells. Additionally, the nicotine-exposed cells had inherently increased levels of intracellular ROS, and acquired stem cell-like sphere formation, as well as epithelial-mesenchymal-transition (EMT) changes during malignant transformation. Treatment with antioxidant NAC resulted in abrogation of EMT and stem cell-like sphere in HK-2 cells, suggesting the role of nicotine-induced ROS in these morphological changes. Additionally, epigenetic reagents 5-aza-2'-deoxycytidine and trichostatin A also diminished stem cell-like sphere in nicotine-exposed HK-2 cells. The nicotine also induced changes in the expression of epigenetic genes (DNMT3a, DNMT3b, and HMT1) and these changes were reversed by NAC treatment. This further supports the role of nicotine-induced ROS in epigenetic changes during malignant transformation of HK-2 cells. The altered levels of pAKT in low dose nicotine exposed cells were restored after NAC treatment, suggesting that nicotine-induced ROS, through regulation of AKT pathway, controls the EMT and stemness during early stages of carcinogenesis. In summary, to our knowledge, this is the first report showing that chronic exposure to nicotine induces malignant transformation in human kidney epithelial cells through ROS-mediated epigenetic modifications.
Citation Format: Yuwei Chang, Kamaleshwar Singh. Nicotine-induced oxidative stress causes epigenetic alterations during malignant transformation of human kidney epithelial cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 879.
Abstract 891: Plumbagin and atovaquone inhibit Na+/K+-ATPase through the generation of oxidative stress
Authors: Alharbi Yousef , Kapur Arvinder , Felder Mildred , Barroilhet Lisa , Pattnaik Bikash , Patankar Manish S. 
Published: August 2019

Abstract
Plumbagin and atovaquone are chemotoxic to ovarian, breast and other tumors. Both molecules inhibit oxidative phosphorylation causing a rapid increase in intracellular oxygen radicals and apoptosis. Oxidative stress is also known to inhibit the activity of Na+/K+-ATPase (NKA), the ion channel that maintains the membrane potential. Here, we investigate if the oxidative stress mediated by plumbagin and atovaquone also leads to inhibition of NKA activity. We confirm that plumbagin and atovaquone inhibit proliferation of three human (OVCAR-3, SKOV-3 and TYKNu) and one mouse (ID8) ovarian cancer cell lines. Using SKOV-3 and OVCAR-3 as models for ovarian cancer, we demonstrate that oxygen radical scavenger, N-acetylcysteine (NAC) attenuated the cytotoxicity of plumbagin and atovaquone. Using whole cell patch clamping we demonstrate that plumbagin and atovaquone inhibit outward and inward current flowing through NKA in SKOV-3 and OVCAR-3. Both drugs decrease cellular ATP. Providing exogenous ATP (5 mM) in the pipet solution used during patch clamping did not recover NKA activity in the plumbagin or atovaquone treated SKOV-3 and OVCAR-3 cells. However, pretreatment of the cells with NAC completely abrogated the NKA inhibitory activity of plumbagin and atovaquone. Exposure of the SKOV-3 cells to either of the drugs for 1-2 h resulted in a significant decrease in the expression of NKA. We conclude that oxidative stress caused by plumbagin and atovaquone degrades NKA and hence the membrane potential cannot be optimally maintained. Evaluation of compounds that induce oxidative stress should therefore consider contribution of NKA inhibition to the cytotoxic activity of such agents.
Citation Format: Yousef Alharbi, Arvinder Kapur, Mildred Felder, Lisa Barroilhet, Bikash Pattnaik, Manish S. Patankar. Plumbagin and atovaquone inhibit Na+/K+-ATPase through the generation of oxidative stress [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 891.
Abstract 895: The identification of molecular mechanism underlying the progression of gastric cancer peritoneal dissemination by senescent fibroblasts
Authors: Yasuda Tadahito , Koiwa Mayu , Uchihara Tomoyuki , Yonemura Atsuko 
Published: August 2019

Abstract
Background: Secreted factors from cancer associated fibroblast (CAFs) is likely to be implicated in cancer progression, but the precise mechanism is not fully understood. It is reported that senescent cells survive and secrete some cytokines, so called senescence-associated secretory phenotype (SASP). The purpose of current study is to identify the molecular mechanism underlying the progression of gastric cancer (GC) peritoneal dissemination by CAFs showing SASP.
Methods: We examined the senescent state of CAFs activated NFkB signaling by inflammatory cytokines (iCAFs) and evaluated the expression of SASP factors. We investigated the growth ability of GC cell lines treated with iCAFs derived condition medium (CM). We transplanted GC cell lines with intraperitoneal administration to generate peritoneal metastasis mouse model and evaluated the influence of SASP factors on cancer progression.
Results: We found that the growth ability of iCAFs decreased and their expression of p16 and p15, which was senescent markers increased. And the comprehensive genomic analysis revealed that iCAFs was highly enriched the senescent related genes and SASP factors related genes. Next, we also found that iCAFs derived CM significantly increased the growth ability of GC cells. Moreover, also in peritoneal metastasis mouse model, iCAFs derived CM remarkably enhanced intraperitoneal tumors.
Conclusion: These findings suggest that SASP factors from senescent CAFs, which activated by inflammatory cytokines can promote peritoneal dissemination of GC cells.
Citation Format: Tadahito Yasuda, Mayu Koiwa, Tomoyuki Uchihara, Atsuko Yonemura. The identification of molecular mechanism underlying the progression of gastric cancer peritoneal dissemination by senescent fibroblasts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 895.
Abstract 896: Knocking out the gene (SNCA) that codes for the Parkinson’s disease-related protein alpha-synuclein in SK-Mel-28 melanoma cells significantly retards tumor growth in SCID mice
Authors: Shekoohi Sahar , Rajasekaran Santhanasabapathy , Yang Shu , Nagarajan Sureshbabu , Patel Dhaval , Yu Xiuping , Witt Stephan N. 
Published: August 2019

Abstract
The Parkinson’s disease-associated protein alpha-synuclein (α-syn) is often highly expressed in melanoma. α-Syn appears to exert a pro-survival function in melanoma cells, possibly by maintaining autophagy homeostasis. The long-term goal of our work is to determine the mechanism by which α-syn confers survival in melanoma cells. Herein, we used CRISPR (clustered regularly interspaced short palindromic repeats) to disrupt SNCA, the gene that codes for α-syn, in the melanoma cell line SK-Mel-28. Western blotting and real-time-qPCR verified that we generated four α-syn knockout (KO) clones. Three clones showed no expression of α-syn, whereas one had about 50% less α-syn than the control cells. DNA sequencing is consistent with three of the clones having both alleles of SNCA knocked out, whereas one clone has only one allele knocked out. α-Syn KO clones were tested in a variety of assays to ascertain the function of α-syn. First, the percentage of cells with exofacial phosphatidylserine (PS) was determined by annexin V-FITC/PI staining in conjunction with fluorescence-activated cell sorting. On average, there was a statistically significant 50% increase in exofacial PS (annexin V+/PI-) in three of the four α-syn KO clones compared to control cells. Exofacial PS was increased in the α-syn KO clones without a concomitant increase in apoptotic cells (annexin V+/PI+). Second, the clones were tested for growth in vivo using SCID mice. All four clones showed a ~65% reduction in the rate of tumor growth, followed over 12 weeks. Third, immunohistochemical staining of excised tumors from the SCID mice showed that the proliferation marker Ki-67 was significantly (p&lt; 0.0001) lower in the tumors generated from the KO clones compared to tumors from control cells. In conclusion, given that α-syn avidly binds to PS, one possibility is that α-syn is like molecular Velcro that binds to PS molecules embedded in the inner leaflet, and this binding helps ATP-driven flippases keep PS in the inner leaflet. Loss α-syn then increases exofacial PS, which is a marker of senescence. Our working model is that α-syn is an anti-senescence protein, and that the α-syn KO clones grow slower than control cells in vivo because the clones have entered a senescent state.
Citation Format: Sahar Shekoohi, Santhanasabapathy Rajasekaran, Shu Yang, Sureshbabu Nagarajan, Dhaval Patel, Xiuping Yu, Stephan N. Witt. Knocking out the gene (SNCA) that codes for the Parkinson’s disease-related protein alpha-synuclein in SK-Mel-28 melanoma cells significantly retards tumor growth in SCID mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 896.
Abstract 903: Real-time imaging of cellular senescence in living animals
Authors: Cui Lina 
Published: August 2019

Abstract
Senescence, a cellular stage that halts proliferation, plays a critical role in cellular processes such as tumor suppression, tumorigenesis and aging. Monitoring of senescence in real-time in living objects not only holds value in basic biological studies, it can also benefit treatments of various diseases such as cancer and age-related conditions. Our lab has developed a series of small molecule based agents for non-invasive imaging of cellular senescence in real-time. We have demonstrated their applications in tumor models receiving chemo- or radiotherapy, as well as aging mice models. These probes will be useful for treatment response monitoring, therapeutic regimen optimization, as well as imaging-guided removal of aged cells.
Citation Format: Lina Cui. Real-time imaging of cellular senescence in living animals [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 903.
Abstract 904: Hypoxic attenuation of ΔB-Raf-induced senescence
Authors: Chang Soojeong , Park Hyunsung 
Published: August 2019

Abstract
Oncogene-induced senescence (OIS) is natural surveillance mechanisms against tumorigenesis. The in-vivo oxygen concentration around tumor microenvironment has been estimated as 3%~0.5%. We investigate the effects of physiological hypoxia (1.5% O2) and pathological hypoxia (&lt;0.5% O2) on OIS. Expression of active ΔB-Raf in human lung fibroblast IMR90 cells triggered senescence processes such as activation of senescence associated-β-galactosidase (SA-β-gal) and senescence associated heterochromatin foci (SAHF). We found that hypoxic condition delayed onset of activation of SA-β-gal. Furthermore hypoxic condition blocked formation of heterochromatin foci which was identified as a hallmark of OIS with increase of histone methylation. Rearrangement of chromatin organization by activated ΔB-Raf was also inhibited under hypoxic condition. This study shows that tumor hypoxia assists the transformed cells to overcome an obstacle of senescence caused by oncogenes. [This study was supported by the National Research Foundation of Korea (NRF), grant 2016R1A2B4012840 and 2018R1A4A1025985]
Citation Format: Soojeong Chang, Hyunsung Park. Hypoxic attenuation of ΔB-Raf-induced senescence [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 904.
Abstract 912: Macrophage inhibitory factor (MIF), osteopontin (OPN) and anti-interleukin-8 (IL-8) autoantibodies (AAb) complement CA125 for detection of early-stage ovarian cancer
Authors: Guo Jing , Yang Wei-lei , Celestino Joseph , Lu Karen , Lokshin Anna E. , Lu Zhen , Bast Robert C. 
Published: August 2019

Abstract
Background: Early detection of ovarian cancer promises to reduce mortality. At present, only 20 percent of ovarian cancer is found in early stage (I-II). CA125 is found in sera from approximately 60% of patients with early stage disease. Greater sensitivity could be observed with a panel of blood tests.
Methods: A panel of 10 antigen biomarkers (MIF, Leptin, IL-6, IL-8, TNFa, OPN, FGF2, HE4, TGFa and a panel of autoantibodies (AAbs) against 12 antigens (IL-8, MDM2, c-myc, PLAT, EpCAM, HOXA7, ENO1, PDI, HSPA5, HSPA8, ANXA2, Cathepsin D) were analyzed in sera of 77 ovarian cancer patients with early stage (I-II), 50 patients with late stage (III-IV), and 216 healthy women from the Normal Risk Ovarian Cancer Screening Study (NROSS) using Luminex-based immunoassays. Serum levels of serum tumor marker CA-125 were routinely measured in all patients using a Roche assay. The most promising markers (CA125, MIF, OPN, and anti-IL-8 autoantibodies were validated using an independent panel with sera from 69 early stage and 50 late ovarian cancer patients and 200 healthy controls.
Result: Serum level of CA125, MIF, OPN and IL-8 AAb were elevated in early stage (I-II) and late stage (III-IV) ovarian cancer patients compared with healthy controls. Analyzing the positive biomarkers in combination with CA125 increased detection of early stage disease from 62% with CA125 alone to 92% a panel of CA125, MIF, OPN and IL-8 AAb at 98% specificity. For patients with late stage disease sensitivity increased from 90% to 98% with the panel. Complementarity of CA125 with MIF, OPN and IL-8 AAb was confirmed with an independent validation set, where sensitivity for early stage disease was improved from 84% to 91% at 98% specificity.
Conclusion: MIF, OPN and IL8 AAb could be used in combination with CA125 to distinguish ovarian cancer patients from health controls with high sensitivity.
Citation Format: Jing Guo, Wei-lei Yang, Joseph Celestino, Karen Lu, Anna E. Lokshin, Zhen Lu, Robert C. Bast. Macrophage inhibitory factor (MIF), osteopontin (OPN) and anti-interleukin-8 (IL-8) autoantibodies (AAb) complement CA125 for detection of early-stage ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 912.
Abstract 95: Synthetic essentiality of chromatin remodeling factor CHD1 in PTEN deficient cancer
Authors: Zhao Di 
Published: August 2019

Abstract
Prostate cancer (PCa) is one of the most common cancer types in mem. Advanced PCa, especially metastatic castration resistant prostate cancer (mCRPC), has high morbidity and mortality. ~50% advanced PCa shows PTEN deletion or mutation, therefore, identification of specific therapeutic targets for PCa harboring PTEN deficiency holds hope for patients with advanced PCa. Taking advantage of the vast public available prostate cancer genome database, we recently explored a novel approach to identify potential therapeutic targets by screening for “synthetic essential” genes that were occasionally deleted in cancer but always retained in the context of tumor suppressor gene deficiency. Using this method, we identified the chromodomain-helicase-DNA-binding protein 1 (CHD1) as a synthetic essential gene in PTEN-deficient PCa. Both human PCa xenograft models and genetically engineered PCa mouse models suggested that depletion of CHD1 suppresses the tumor growth and progression of PTEN-deficient PCa, but has minimal effects on normal prostate tissue or PTEN-intact PCa. Importantly, CHD1 inhibition leads to a significantly prolonged overall survival in PTEN-loss PCa mouse model. Mechanistically, we found that PTEN-PI3K-AKT-GSK3βpathway regulates CHD1 phosphorylation, followed by ubiquitination and degradation via β-TrCP mediated proteasome pathway. The ChIP-seq and transcriptional profiling analyses uncovered that, in PCa with PTEN loss, CHD1 is stabilized and interacts with epigenetic marker H3K4me3, resulting in the transcriptional activation of NF-κB network genes. Furthermore, immunophenotyping using Mass Cytometry (CyTOF) and functional validation suggested that CHD1 contributes to the immunosuppressive tumor microenvironment in PCa through stimulating the expansion and activation of myeloid-derived suppressor cell (MDSCs) and reducing tumor-infiltrating CD8+ T-cells. Together, this study demonstrated that CHD1 plays important roles in tumor initiation and progression of PTEN-deficient PCa, and presents a promising context-specific therapeutic target in PCa. In addition, the novel approach of “synthetic essentiality” we proposed provides a good tool to identify context-specific therapeutic targets for undruggable tumor suppressor deficiency in cancer genome.
Citation Format: Di Zhao. Synthetic essentiality of chromatin remodeling factor CHD1 in PTEN deficient cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 95.