bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 678: Raf-1 cysteine-rich domain (CRD) supports active orientations of KRas4B/Raf-1 at the membrane
Authors: Jang Hyunbum , Nussinov Ruth 
Published: August 2018

Abstract
Ras is a small GTPase, controlling signal transduction pathways and promoting cell proliferation and survival. In cancer, there are two independent pathways in tumor proliferation: one includes Raf/MEK/ERK (MAPK) and PI3K/Akt/mTOR. KRas4B is the most abundant oncogenic isoform. In the MAPK pathway, KRas4B preferentially recruits Raf-1 and activates it. The high-affinity interaction of Ras binding domain (RBD) of Raf with Ras was solved, but the relative position of Raf's cysteine-rich domain (CRD) in the Ras/Raf complex at the membrane and the key question of exactly how it affects Raf signaling are daunting. Here, we employ all-atom MD simulations to investigate membrane-anchored Raf-1 CRD and suggest a model of KRas4B/Raf-1 complex at the anionic lipid bilayer composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dioleoyl-sn-glycero-3-phosphoserine (DOPS) in mole ratio 4:1. Active Ras modulates Raf activation, with KRas4B preferentially activating Raf-1. We show that the Raf-1 CRD stably binds anionic lipid bilayers inserting a positively-charged loop into the amphipathic interface. The loop contains key basic residues, responsible for the membrane association. Importantly, when in complex with Ras/RBD, covalently-connected CRD presents the same membrane interaction mechanism, with CRD locating at the space between the RBD and membrane, suggesting that CRD is an intrinsic membrane binding domain of Raf kinase. To date, CRD's role was viewed in terms of stabilizing Raf-membrane interaction. Our observations argue for a key role of CRD that Raf-1 CRD not only offers an additional anchor for the KRas4B/Raf-1 complex, but by reducing the fluctuations of Ras/RBD it also increases the population of Ras/RBD at the membrane and enhances the already high affinity between Ras and RBD. In the KRas4B/RBD-CRD complex, Raf-1 CRD supports the active-state Ras orientation at the membrane, releasing the catalytic domain from the transiently confined orientation. This promotes MAPK signaling, the key Ras proliferative pathway, above other pathways. Even though in the absence of CRD the Ras/Raf-1 RBD interaction can elicit MAPK signaling, the enhanced stability of the complex at the membrane rendered by CRD can considerably intensify it, by helping in Raf's dimerization. Our data reveal these significant roles of CRD at the membrane in the Raf activation. Funded by Frederick National Laboratory for Cancer Research, National Institutes of Health, under contract HHSN261200800001E.
Citation Format: Hyunbum Jang, Ruth Nussinov. Raf-1 cysteine-rich domain (CRD) supports active orientations of KRas4B/Raf-1 at the membrane [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 678.
Abstract 680: FLLL12 is a small molecule JAK2 inhibitor that inhibits JAK-STAT3 pathway in head and neck cancer
Authors: Amin ARM Ruhul , Anisuzzaman ASM , Siddique Abu B. , Fuchs James R. 
Published: August 2018

Abstract
Purpose: We have recently reported that FLLL12, a synthetic curcumin analog, induces apoptosis of lung cancer cells through a death receptor (DR) 5-dependent pathway and in squamous cell carcinoma of head and neck (SCCHN) by modifying multiple Bcl-2 proteins. However, the direct molecular target (receptor) of FLLL12 is unknown. The purpose of the current study is to identify the receptor of FLLL12.
Methods: Computer-aided molecular docking was used to predict molecular interaction. Isothermal titration calorimetry and thermal shift assays were used to confirm molecular interactions in a cell free system. SCCHN cell lines were used to study the effect of this interaction on JAK-STAT3 pathway. Protein expression levels were measured by Western blotting.
Results: Computer-aided molecular docking modeling of FLLL12 and JAK2 (PDB code: 5CF5) predicted that FLLL12 fit well into the JAK2 catalytic pocket. Although curcumin also fit into the JAK2 catalytic pocket, the binding sites were different for FLLL12 and curcumin. Docking score for FLLL12, natural ligand and curcumin were -7.2, -12.1 and -6.9, respectively. FLLL12 also docked into the STAT3 catalytic pocket (PDB code: 5AX3). However, the docking score was worse than those for natural ligand and curcumin (-5.1, -7.3 and -7.4 respectively). We confirmed that FLLL12 interacted with JAK2 in a cell free system using recombinant JAK2. Isothermal titration calorimetry assay revealed one binding site for both FLLL12 and the FDA-approved JAK inhibitor ruxolitinib. The Ka values were 3.84E6±1.03E5 and 2.31E7±6.78E6 M-1, respectively. FLLL12 and JAK2 interactions were further confirmed by thermal shift assay. Kd values were 1.12±0.14 μM and 2.24 ±0.18 μM for ruxolitinib and FLLL12, respectively. Two hour pretreatment with FLLL12 also inhibited IL-6 induced phosphorylation of JAK2 and STAT3. Finally, FLLL12 strongly inhibited constitutively active STAT3 phosphorylation in SCCHN cell lines, a downstream effector of JAK.
Conclusions: Our results strongly suggest that FLLL12 is a novel small molecule inhibitor for JAK2 and FLLL12-JAK2 interaction inhibits IL-6-induced as well as constitutively active STAT3 phosphorylation, thus has great promise for cancer prevention and therapy. Grant Support: Start-up fund from Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University and from Department of Pharmaceutical Sciences and Research, Marshall University.
Citation Format: ARM Ruhul Amin, ASM Anisuzzaman, Abu B. Siddique, James R. Fuchs. FLLL12 is a small molecule JAK2 inhibitor that inhibits JAK-STAT3 pathway in head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 680.
Abstract 688: Triphenylstannyl 2-(benzylcarbamoyl)benzoate (Ch-319) modulates AKT/FOXO3a signaling and inhibits progression of prostate cancer
Authors: Waseem Durdana , Syed Deeba N. , Khan Gul Majid , Haq Ihsan-ul , Mukhtar Hasan 
Published: August 2018

Abstract
Prostate cancer (PCa) is the most commonly diagnosed non-cutaneous malignancy in men in the United States. Moreover, its incidence is predicted to surge in many parts of the world due to increase in aging population and change in dietary habits. The PTEN/AKT axis plays a critical role in regulating PCa growth and survival. Synthetic and natural compounds have been explored in preclinical models as potential inhibitors of AKT pathway that can suppress proliferation or induce apoptosis in PCa cells. Triphenyltin compounds are complexes of tin with three phenyl groups attached to hydrocarbon ligands. Structural modifications have been attempted to yield organotins with enhanced cytotoxicity against cancer cells. Here, we synthesized a series of triphenyltin (IV) carboxylate derivatives and evaluated their efficacy against PCa. From this library, triphenylstannyl 2-(benzylcarbamoyl)benzoate (Ch-319) was selected for further studies on the basis of its selective cytotoxicity towards cancer cells. Treatment of PTEN-null PC3M and DU145 PCa cells with Ch-319 (250-500 nM) resulted in reduced viability and induction of cell cycle arrest associated with downregulation of PI3K and dephosphorylation of AKT and PRAS40. In parallel, elevation of FOXO3a expression, activation of pro-apoptotic Bax and downregulation of anti-apoptotic Bcl2 protein was observed. Flowcytometry revealed increased population of apoptotic cells in Ch-319 treated cells. Presensitization of PCa cells with Ch-319 augmented the effect of cabazitaxel, a commonly used taxane in patients with castration-resistant PCa. We next evaluated the effect of Ch-319 in a prostate-specific Pten-/- model where AKT activation is the major driving force for development of prostate adenocarcinoma. Mice treated with Ch-319 (5 µg/animal:intraperitoneally) for 6 weeks showed decreased tumor weights as compared to DMSO treated controls. Histological studies indicated a decrease in the number and size of foci in Ch-319 treated tumors. Consistently, reduced expression of androgen receptor, decreased phosphorylation of AKT and PRAS40 and increase in FOXO3a was observed in Ch-319 treated animals with no signs of organ toxicity. Our studies identify AKT/FOXO3a signaling as a target of triphenyltin (IV) carboxylate derivative Ch-319 and provide a molecular basis of its growth inhibitory effect in PCa cells. We propose that Ch-319 has potential to be developed as an anticancer agent against PCa.
Citation Format: Durdana Waseem, Deeba N. Syed, Gul Majid Khan, Ihsan-ul Haq, Hasan Mukhtar. Triphenylstannyl 2-(benzylcarbamoyl)benzoate (Ch-319) modulates AKT/FOXO3a signaling and inhibits progression of prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 688.
Abstract 689: Identification and optimization of novel chemical matter via a structure-based approach resulting in a probe for MTH1
Authors: Bauser Marcus , Giese Anja , Ellermann Manuel , Guenther Judith , Eheim Ashley , Bunse Stefanie , Neuhaus Roland , Weiske Joerg , Quanz Maria , Glasauer Andrea , Nowak-Reppel Katrin , Bader Benjamin , Irlbacher Horst , Meyer Hanna , Queisser Nina , Haegebarth Andrea , Gorjanacz Matyas , Tresaugues Lionel , Ginman Tobias , Rahm Fredrik , Andersson Martin , Ericsson Ulrica , Forsblom Rickard , Lindstroem Johan , Silvander Camilla , Vicklund Jenny 
Published: August 2018

Abstract
Cancer cells can form reactive oxygen species (ROS) due to altered redox regulation that affect desoxynucleosides triphosphates (dNTP) in particular. 8-oxo-2'-deoxyguanosine-5'-triphosphate (8-oxo-dGTP) and 2-hydroxydeoxyadenosine-5'-triphosphate (2-OH-dATP) are the two most abundant oxidative nucleotide lesions in this respect. These undesired nucleoside triphosphates are sanitized by the hydrolase MTH1 (also known as NUDT1) in order to prevent their incorporation into replicating DNA. Sprint Bioscience created a series of drug-like, potent and selective MTH1 inhibitors using fragment-based drug discovery methods. In collaboration with Bayer, these inhibitors were extensively profiled, both in vitro and in vivo, to allow for the selection of a probe molecule with attractive properties for in vivo target validation studies. Herein, we would like to share novel chemical matter and it's binding to MTH1 in protein co-crystal structures. Furthermore, we describe the consecutive, stepwise structure-based optimization process. Extensive SAR elaboration clearly revealed the essential moieties for high potency and favorable ADME properties. We are able to report for the first time how we identified BAY-707 as a very potent and highly selective MTH1 inhibitor representing a potential probe to further evaluate the scope and limitations of MTH1 inhibition for therapeutic applications.
Citation Format: Marcus Bauser, Anja Giese, Manuel Ellermann, Judith Guenther, Ashley Eheim, Stefanie Bunse, Roland Neuhaus, Joerg Weiske, Maria Quanz, Andrea Glasauer, Katrin Nowak-Reppel, Benjamin Bader, Horst Irlbacher, Hanna Meyer, Nina Queisser, Andrea Haegebarth, Matyas Gorjanacz, Lionel Tresaugues, Tobias Ginman, Fredrik Rahm, Martin Andersson, Ulrica Ericsson, Rickard Forsblom, Johan Lindstroem, Camilla Silvander, Jenny Vicklund. Identification and optimization of novel chemical matter via a structure-based approach resulting in a probe for MTH1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 689.
Abstract 706: In vivo tumor-associated mutation screen identifies PI3K activation as a mechanism of resistance to PD-1 blockade
Authors: Collins Natalie B. , Miller Brian C. , Bi Kevin , Abosy Rose Al , Yates Kathleen , Shrestha Yashaswi , Doench John , Boehm Jesse , Haining W Nicholas 
Published: August 2018

Abstract
Known genomic correlates of response to immunotherapy do not perfectly predict clinical outcome, supporting the existence of unknown mechanisms of resistance to tumor immunity. We hypothesize that somatic, cancer-associated mutations account for heterogeneity in spontaneous response to tumors and response to immunotherapy. We have undertaken a systematic in vivo screen to identify mechanisms of resistance to tumor immunity in order to define a comprehensive set of therapeutic targets and provide biomarkers of sensitivity to immunotherapy. Mouse tumor cell lines (MC38 colon carcinoma or B16 melanoma) were engineered to express a library of barcoded open reading frames (ORFs) mutagenized to encode known cancer-associated somatic mutations. Tumor-bearing animals were treated with anti-PD-1. A mutation in Phospho-Inositol 3 Kinase (PI3K), PIK3CA c.3140A&gt;G, increased in representation in anti-PD-1 treated tumors but not in immunodeficient animals, suggesting that activity of the mutant allele conferred selective growth advantage in the setting of tumor immunity. This mutation encodes a constitutively active mutant catalytic domain, PIK3CA H1047R. MC38 tumors homogeneously expressing H1047R and implanted into wild-type mice failed to respond to anti-PD-1 therapy, while tumors expressing a control gene regressed. Pharmacologic PI3K inhibition resensitized tumors to treatment with anti-PD-1. PD-1-treated PIK3CA H1047R tumors had fewer infiltrating CD8+ T cells as measured by immunohistochemistry and flow cytometry. Single-cell RNA-seq of tumor-infiltrating immune cells revealed a population of myeloid cells expressing known immune inhibitory proteins that differentially enriched in PIK3CA H1047R-expressing tumors. Our data suggest that PI3K has, in addition to its well-described oncogenic role, a role in tumor immune evasion mediated by establishment of an inhibitory myeloid microenvironment. As such, activating mutations in PI3K may be useful as a biomarker of poor response to immunotherapy, and these studies provide a rationale for therapeutic combination trials of PI3K inhibition with checkpoint blockade and other myeloid-targeting immunotherapies.
Citation Format: Natalie B. Collins, Brian C. Miller, Kevin Bi, Rose Al Abosy, Kathleen Yates, Yashaswi Shrestha, John Doench, Jesse Boehm, W Nicholas Haining. In vivo tumor-associated mutation screen identifies PI3K activation as a mechanism of resistance to PD-1 blockade [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 706.
Abstract 721: Development of a therapeutic HPV vaccine based on mass spectrometry-verified target epitopes
Authors: Kruse Sebastian , Bonsack Maria , Becker Sara , Mohan Nitya , Steinbach Alina , Hoppe Stephanie , Blatnik Renata , Riemer Angelika B. 
Published: August 2018

Abstract
For rational therapeutic vaccine design, detailed knowledge about target epitopes that are truly presented on cancer cells is essential. Many potential tumor-specific epitopes, such as viral epitopes or mutation-derived neoepitopes, are presented at low abundance. Thus, detection of these epitopes remains a challenge. We have developed a high-sensitivity targeted mass spectrometry (MS) approach for direct detection of low-abundant epitopes. We used human papillomavirus (HPV) as a model system, as high-risk HPVs cause over 600,000 cervical, anogenital and oropharyngeal cancer cases per year. Moreover, the HPV oncoproteins E6 and E7 are essential for the induction and maintenance of the malignant phenotype, and thus are ideal targets for immunotherapy.
Potential HPV16 E6 and E7 target epitopes were predicted in silico and their HLA-binding verified in cellular binding assays. HLA-peptide complexes were immunoprecipitated from HPV16-positive cancer cells and the purified peptides were analyzed by MS. Identified HPV epitopes were assessed for immunogenicity in vitro with PBMC from healthy donors and in vivo in the MHC-humanized mouse model A2.DR1.
The binding assays resulted in the identification of known and novel HPV16-derived HLA-binding peptides. Furthermore, we used this data to formulate rules on how to optimally use epitope prediction tools to increase the chances of predicting true HLA ligands. 14 HLA-A2-restricted HPV16 epitopes were detected on the surface of CaSki and 866 cervical cancer cells, 9 of which were novel. 13 out of the 14 MS-detected peptides were immunogenic in ELISpot assays. Vaccination of A2.DR1 mice with one selected epitope induced high numbers of specific cytotoxic T-cells, and caused anti-tumor effects in a newly developed HPV16 E6/E7-expressing A2.DR1-compatible tumor model.
We conclude that our epitope detection and validation approach is suitable for validating even low-abundant candidate epitopes to be true immunotherapy targets. MS-detection of epitopes appears to be a good predictor of immunogenicity, which makes this approach an attractive platform for determining target epitopes for therapeutic cancer vaccines.
Citation Format: Sebastian Kruse, Maria Bonsack, Sara Becker, Nitya Mohan, Alina Steinbach, Stephanie Hoppe, Renata Blatnik, Angelika B. Riemer. Development of a therapeutic HPV vaccine based on mass spectrometry-verified target epitopes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 721.
Abstract 723: Targeting phosphorylated p53 to elicit tumor-reactive T helper responses against head and neck squamous cell carcinoma
Authors: Ohara Kenzo , Kumai Takumi , Hayashi Tatsuya , Ohkuri Takayuki , Bandoh Nobuyuki , Kobayashi Hiroya , Harabuchi Yasuaki 
Published: August 2018

Abstract
The p53 is a DNA-binding and transcription activation domain containing tumor suppressor that upregulates growth arrest and apoptosis-related genes. In response to DNA damage, p53 is phosphorylated at multiple sites including serine 33 or 37. Additionally, abnormal phosphorylation of cellular proteins is a hallmark of malignant transformation. The human immune system is capable of distinguishing between the normal components and these posttranslational modifications. Therefore, the existence of posttranslational modifications increases the diversity of potential immune reactions to a determinant antigen. We identified phosphorylated peptide epitopes from tumor protein p53 that could elicit effective T helper-cell responses. Two epitope peptides, p5322-41/Phospho-S33 and p5322-41/Phospho-S37, induced T helper responses against tumor cells expressing phosphorylated p53 protein. Moreover, cisplatin and doxorubicin augmented the responses of such CD4+ T cells via upregulation of phosphorylated p53. Importantly, we elucidated the presence of peripheral blood lymphocytes specific for these peptide epitopes in the PBMCs of head and neck squamous cell cancer patients. These results predict that epitopes p5322-41/Phospho-S33 and p5322-41/Phospho-S37 are immunogenic for anti-tumor responses and could be beneficial for cancer immunotherapy.
Citation Format: Kenzo Ohara, Takumi Kumai, Tatsuya Hayashi, Takayuki Ohkuri, Nobuyuki Bandoh, Hiroya Kobayashi, Yasuaki Harabuchi. Targeting phosphorylated p53 to elicit tumor-reactive T helper responses against head and neck squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 723.
Abstract 725: Targeting the skin microenvironment for effective cancer vaccines
Authors: You Jack R. , Hao Rong , Falo Louis D. , Chen Guo , Hao Xingxing , Carey Cara , You Zhaoyang , Falo Louis D. 
Published: August 2018

Abstract
Skin, the most accessible organ, harbors keratinocytes and immunocytes that contribute to both innate and adaptive immunity, rendering it an ideal anatomic target for immunization. Keratinocytes can drive skin inflammation by producing pro-inflammatory mediators that promote cutaneous immune responses. Thus, targeting accessible keratinocytes to express transgenic antigens and increase production of pro-inflammatory mediators is a salient and attractive approach to vaccination, but remains a critical challenge to achieve. Toward this goal, we evaluated the effects of transient overexpression of the stress response factor x-box binding protein 1 (XBP1) in keratinocytes on the skin microenvironment. In vitro, keratinocytes genetically engineered to overexpress XBP1 increased production of both co-transduced exogenous antigen and pro-inflammatory mediators. In vivo, overexpression of XBP1 and transgenic antigen in keratinocytes induced both protective and therapeutic antitumor immunity that was associated with enhanced cutaneous expression of pro-inflammatory mediators and co-delivered antigen, increased skin-infiltrating immunocytes including dendritic cells (DCs), and the induction of durable antigen-specific CD8+ T cells and skin-resident memory CD8+ T cells. Importantly, in human skin, correlative effects were observed: transient overexpression of XBP1 in skin triggered the expression of genes linked to a pro-immunogenic microenvironment, increased the expression of the co-delivered antigen, and promoted the activation and IFN-γ-producing T cell-stimulating function of skin DCs. These findings provide novel insights into the rational design of cancer vaccines with improved immunogenicity through strategic modulation of the skin microenvironment.
Citation Format: Jack R. You, Rong Hao, Louis D. Falo, Guo Chen, Xingxing Hao, Cara Carey, Zhaoyang You, Louis D. Falo. Targeting the skin microenvironment for effective cancer vaccines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 725.