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https://www.readbyqxmd.com/read/28647697/analysis-of-k-ras-interactions-by-biotin-ligase-tagging
#1
Christopher Ritchie, Andrew Mack, Logan Harper, Ayna Alfadhli, Philip J S Stork, Xiaolin Nan, Eric Barklis
BACKGROUND: Mutations of the human K-Ras 4B (K-Ras) G protein are associated with a significant proportion of all human cancers. Despite this fact, a comprehensive analysis of K-Ras interactions is lacking. Our investigations focus on characterization of the K-Ras interaction network. MATERIALS AND METHODS: We employed a biotin ligase-tagging approach, in which tagged K-Ras proteins biotinylate neighbor proteins in a proximity-dependent fashion, and proteins are identified via mass spectrometry (MS) sequencing...
July 2017: Cancer Genomics & Proteomics
https://www.readbyqxmd.com/read/28644440/lncrna-sarcc-suppresses-renal-cell-carcinoma-rcc-progression-via-altering-the-androgen-receptor-ar-mirna-143-3p-signals
#2
Wei Zhai, Yin Sun, Changcheng Guo, Guanghui Hu, Mingchao Wang, Jiayi Zheng, WanYing Lin, Qingbo Huang, Gonghui Li, Junhua Zheng, Chawnshang Chang
While the androgen receptor (AR) might promote renal cell carcinoma (RCC) initiation and progression, the molecular mechanisms involved remain largely unclear. Here, we discovered the novel LncRNA-SARCC, which was suppressed and associated with better prognosis in RCC. Preclinical studies using multiple RCC cells and in vivo mouse model indicated that LncRNA-SARCC could attenuate RCC cell invasion, migration and proliferation in vitro and in vivo. Mechanistically, LncRNA-SARCC bound and destabilized AR protein with an inhibition of AR function, which led to transcriptionally de-repress miR-143-3p expression, thus inhibition of its downstream signals including AKT, MMP-13, K-RAS and P-ERK...
June 23, 2017: Cell Death and Differentiation
https://www.readbyqxmd.com/read/28641032/targeting-rho-gtpase-effector-p21-activated-kinase-4-pak4-suppresses-p-bad-microrna-drug-resistance-axis-leading-to-inhibition-of-pancreatic-ductal-adenocarcinoma-proliferation
#3
Ramzi M Mohammad, Yiwei Li, Irfana Muqbil, Amro Aboukameel, William Senapedis, Erkan Baloglu, Yosef Landesman, Philip A Philip, Asfar S Azmi
Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive and therapy resistant malignancy. Mutant K-Ras, found in >90% of refractory PDAC, acts as a molecular switch activating Rho GTPase signaling that in turn promotes a plethora of pro-survival molecules and oncogenic microRNAs. We investigated the impact of Rho GTPase effector protein p21 activated kinase 4 (PAK4) inhibition on pro-survival p-Bad and oncogenic miRNA signaling. We demonstrate that the dual NAMPT and PAK4 modulators (KPT-9274 and KPT-9307) inhibit PDAC cell proliferation through down-regulation of Bad phosphorylation and up-regulation tumor suppressive miRNAs (miR-145, let-7c, let-7d, miR-34c, miR320 and miR-100)...
June 22, 2017: Small GTPases
https://www.readbyqxmd.com/read/28630043/the-small-gtpases-k-ras-n-ras-and-h-ras-have-distinct-biochemical-properties-determined-by-allosteric-effects
#4
Christian W Johnson, Derion Reid, Jillian A Parker, Shores Salter, Ryan Knihtila, Petr Kuzmic, Carla Mattos
H-, K-, and N-Ras are small GTPases that are important in the control of cell proliferation, differentiation and survival, and their mutants occur frequently in human cancers. The G-domain, which catalyzes GTP hydrolysis and mediates downstream signaling, is 95% conserved between the Ras isoforms. Due to their very high sequence identity, biochemical studies done on H-Ras have been considered representative of all three Ras proteins. We show here that this is not a valid assumption. Using enzyme kinetic assays under identical conditions, we observed clear differences between the three isoforms in intrinsic catalysis of GTP by Ras in the absence and presence of the Ras-binding domain (RBD) of the C-Raf Kinase protein (Raf-RBD)...
June 19, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28623230/flexible-body-motions-of-calmodulin-and-the-farnesylated-hypervariable-region-yield-a-high-affinity-interaction-enabling-k-ras4b-membrane-extraction
#5
Hyunbum Jang, Avik Banerjee, Tanmay Chavan, Vadim Gaponenko, Ruth Nussinov
In calmodulin (CaM)-rich environments, oncogenic KRAS plays a critical role in adenocarcinomas by promoting PI3K/Akt signaling. We previously proposed that at elevated calcium levels in cancer, CaM recruits PI3Kα to the membrane and extracts K-Ras4B from the membrane, organizing a K-Ras4B/CaM/PI3Kα ternary complex. CaM can thereby replace a missing receptor tyrosine kinase signal to fully activate PI3Kα. Recent experimental data show that CaM selectively promotes K-Ras signaling, but not of N-Ras or H-Ras...
June 16, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28621541/expanding-the-scope-of-electrophiles-capable-of-targeting-k-ras-oncogenes
#6
Lynn M McGregor, Meredith L Jenkins, Caitlin Kerwin, John E Burke, Kevan M Shokat
There is growing interest in reversible and irreversible covalent inhibitors that target noncatalytic amino acids in target proteins. With a goal of targeting oncogenic K-Ras variants (e.g., G12D) by expanding the types of amino acids that can be targeted by covalent inhibitors, we survey a set of electrophiles for their ability to label carboxylates. We functionalized an optimized ligand for the K-Ras switch II pocket with a set of electrophiles previously reported to react with carboxylates and characterized the ability of these compounds to react with model nucleophiles and oncogenic K-Ras proteins...
June 16, 2017: Biochemistry
https://www.readbyqxmd.com/read/28616082/prevalence-of-pks-positive-escherichia-coli-in-japanese-patients-with-or-without-colorectal-cancer
#7
Takayuki Shimpoh, Yoshihiro Hirata, Sozaburo Ihara, Nobumi Suzuki, Hiroto Kinoshita, Yoku Hayakawa, Yumiko Ota, Akiko Narita, Shuntaro Yoshida, Atsuo Yamada, Kazuhiko Koike
BACKGROUND: Recent studies show that some Escherichia coli strains possessing a gene cluster named the pks island might have a causative role in the development of human colorectal cancer (CRC). In several reports from Europe, they are found more prevalently in colon tissue specimens derived from CRC patients compared to those from controls. In this study we sought to clarify the difference in pks prevalence between CRC patients and non-CRC controls in the Japanese population, by using non-invasive sample collection technique during colonoscopy...
2017: Gut Pathogens
https://www.readbyqxmd.com/read/28611978/periodontal-pathogens-in-the-etiology-of-pancreatic-cancer
#8
REVIEW
Mesut Öğrendik
BACKGROUND: Pancreatic cancer is the fourth leading cause of cancer-related deaths worldwide. Chronic pancreatitis is frequently observed in patients with pancreatic cancer, and a significant relationship between orodigestive cancer-related deaths and chronic periodontitis has been detected. Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola, collectively called the Red complex, are the major pathogens responsible for chronic periodontitis and secrete peptidylarginine deiminase...
March 2017: Gastrointestinal Tumors
https://www.readbyqxmd.com/read/28604746/oncogenic-k-ras-upregulates-itga6-expression-via-fosl1-to-induce-anoikis-resistance-and-synergizes-with-%C3%AE-v-class-integrins-to-promote-emt
#9
K Zhang, S-M Myllymäki, P Gao, R Devarajan, V Kytölä, M Nykter, G-H Wei, A Manninen
In many cancer types, integrin-mediated signaling regulates proliferation, survival and invasion of tumorigenic cells. However, it is still unclear how integrins crosstalk with oncogenes to regulate tumorigenesis and metastasis. Here we show that oncogenic K-Ras(V12) upregulates α6-integrin expression in Madin-Darby canine kidney (MDCK) cells via activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK)/Fos-related antigen 1-signaling cascade. Activated α6-integrins promoted metastatic capacity and anoikis resistance, and led to perturbed growth of MDCK cysts...
June 12, 2017: Oncogene
https://www.readbyqxmd.com/read/28600477/targeting-the-wnt-pathway-and-cancer-stem-cells-with-anti-progastrin-humanized-antibodies-a-major-breakthrough-for-k-ras-mutated-colorectal-cancer-treatment
#10
Alexandre Prieur, Monica Cappellini, Guillaume Habif, Marie-Paule Lefranc, Thibault Mazard, Eric Morency, Jean-Marc Pascussi, Maud Flaceliere, Nathalie Cahuzac, Berengere Vire, Benjamin Dubuc, Amandine Durochat, Pierre Liaud, Jérémy Ollier, Caroline Pfeiffer, Sophie Poupeau, Véronique Saywell, Chris Planque, Eric Assenat, Frédéric Bibeau, Jean-François Bourgaux, Pascal Pujol, Alain Sézeur, Marc Ychou, Dominique Joubert
<p>Patients with metastatic colorectal cancer (CRC) suffer from disease relapse mainly due to cancer stem cells (CSC). Interestingly, they have an increased level of blood progastrin, a tumor-promoting peptide essential for the self-renewal of colon CSCs, which is also a direct b-catenin/Tcf4 target gene. In this study we aimed to develop a novel targeted therapy to neutralize secreted progastrin in order to inhibit Wnt signaling, CSCs and reduce relapses.</p> Experimental Design: <p>Antibodies (monoclonal and humanized) directed against progastrin were produced and selected for target specificity and affinity...
June 9, 2017: Clinical Cancer Research: An Official Journal of the American Association for Cancer Research
https://www.readbyqxmd.com/read/28599309/marsdenia-tenacissima-extract-overcomes-axl-and-met-mediated-erlotinib-and-gefitinib-cross-resistance-in-non-small-cell-lung-cancer-cells
#11
Shu-Yan Han, Wei Zhao, Hai-Bo Han, Hong Sun, Dong Xue, Yan-Na Jiao, Xi-Ran He, Shan-Tong Jiang, Ping-Ping Li
Tyrosine kinase inhibitors (TKIs) are an effective treatment strategy for non-small cell lung cancer (NSCLC) patients harboring mutations that result in constitutive activation of the epidermal growth factor receptor (EGFR). However, most patients eventually develop resistance to TKIs. This occurs due to additional EGFR mutations or the activation of bypass signaling pathways. In our previous work, we demonstrated that Marsdenia tenacissima extract (MTE) restored gefitinib sensitivity in resistant NSCLC cells with EGFR T790M or K-ras mutations...
May 24, 2017: Oncotarget
https://www.readbyqxmd.com/read/28599287/gene-polymorphisms-in-the-pi3k-akt-mtor-signaling-pathway-contribute-to-prostate-cancer-susceptibility-in-chinese-men
#12
Ting Liu, Abulajiang Gulinaer, Xiaoli Shi, Feng Wang, Hengqing An, Wenli Cui, Qiaoxin Li
In this hospital-based case-control study of 413 prostate cancer (PCa) cases and 807 cancer-free controls, we investigated the role of functional single nucleotide polymorphisms (SNPs) of pivotal genes in the PI3K/AKT/mTOR pathway. We genotyped 17 SNPs in mTOR, Raptor, AKT1, AKT2, PTEN, and K-ras and found that 4 were associated with PCa susceptibility. Among the variants, the homozygote variant CC genotype of mTOR rs17036508 C>T were associated with higher PCa risk than the wild TT genotypes (adjusted OR = 3...
May 22, 2017: Oncotarget
https://www.readbyqxmd.com/read/28581516/pancreatic-cancer-heterogeneity-and-response-to-mek-inhibition
#13
K Pedersen, F Bilal, C Bernadó Morales, M T Salcedo, T Macarulla, D Massó-Vallés, V Mohan, A Vivancos, M-J Carreras, X Serres, M Abu-Suboh, J Balsells, E Allende, I Sagi, L Soucek, J Tabernero, J Arribas
Our increasing knowledge of the mechanisms behind the progression of pancreatic cancer (PC) has not yet translated into effective treatments. Many promising drugs have failed in the clinic, highlighting the need for better preclinical models to assess drug efficacy and characterize mechanisms of resistance. Using different experimental models, including patient-derived xenografts (PDXs), we gauged the efficacy of therapies aimed at two hallmark lesions of PCs: activation of signaling pathways by oncogenic KRAS and inactivation of tumor-suppressor genes...
June 5, 2017: Oncogene
https://www.readbyqxmd.com/read/28577599/molecular-inversion-probes-equipped-with-discontinuous-rolling-cycle-amplification-for-targeting-nucleotide-variants-determining-smn1-and-smn2-genes-in-diagnosis-of-spinal-muscular-atrophy
#14
Hwang-Shang Kou, Chun-Chi Wang
The novel techniques of molecular inversion probes (MIPs) combined with discontinuous rolling cycle amplification (DRCA) was developed for determination of the multi-nucleotide variants at single base. The different-length MIPs, a padlock-probe based technology, are designed to simultaneously recognize the identical nucleotide variants. After ligation and DRCA, the different-length genetic products representing the certain genotypes could be simply determined by the short-end capillary electrophoresis (CE) method...
July 18, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28562352/rapalogs-can-promote-cancer-cell-stemness-in-vitro-in-a-galectin-1-and-h-ras-dependent-manner
#15
Itziar M D Posada, Benoit Lectez, Mukund Sharma, Christina Oetken-Lindholm, Laxman Yetukuri, Yong Zhou, Tero Aittokallio, Daniel Abankwa
Currently several combination treatments of mTor- and Ras-pathway inhibitors are being tested in cancer therapy. While multiple feedback loops render these central signaling pathways robust, they complicate drug targeting.Here, we describe a novel H-ras specific feedback, which leads to an inadvertent rapalog induced activation of tumorigenicity in Ras transformed cells. We find that rapalogs specifically increase nanoscale clustering (nanoclustering) of oncogenic H-ras but not K-ras on the plasma membrane...
May 11, 2017: Oncotarget
https://www.readbyqxmd.com/read/28559118/tumor-regression-grades-k-ras-mutational-profile-and-c-met-in-colorectal-liver-metastases
#16
Laura Lorenzon, Luana Ricca, Emanuela Pilozzi, Antoinette Lemoine, Valentina Riggio, Maria Teresa Giudice, Giuseppe Mallel, Flavio Fochetti, Genoveffa Balducci
INTRODUCTION: Recently TRG, necrosis grade and the rate of viable cancer cells of colorectal liver metastases were correlated with the response to chemotherapy treatments, whereas K-RAS mutations and c-MET over-expression were correlated with the prognosis. METHODS: 58 resection specimens were assessed for regression grades. Patients undergone neo-adjuvant treatments were compared to patients who underwent therapy exclusively adjuvantly. We investigated the K-RAS mutational profile, the c-MET over-expression along with patients' survivals curves...
April 21, 2017: Pathology, Research and Practice
https://www.readbyqxmd.com/read/28551612/pancreatic-cancer-stem-cells-and-therapeutic-approaches
#17
REVIEW
Gulinnaz Ercan, Ayfer Karlitepe, Bulent Ozpolat
Pancreatic ductal adenocarcinoma (PDAC) is considered one of the deadliest human cancers, with 1-5% 5-year survival rates (~6-month median survival duration) despite therapy; thus, PDAC represents an unmet therapeutic challenge. PDAC is the major histological subtype, comprising 90% of all pancreatic cancers. It is a highly complex and aggressive malignancy, presenting with early local invasion and metastasis, and is resistant to most therapies, all of which are believed to contribute to its extremely poor prognosis...
June 2017: Anticancer Research
https://www.readbyqxmd.com/read/28544747/k-ras-mutation-and-amplification-status-is-predictive-of-resistance-and-high-basal-pakt-is-predictive-of-sensitivity-to-everolimus-in-biliary-tract-cancer-cell-lines
#18
Yvonne Yeung, David K Lau, Fiona Chionh, Hoanh Tran, Janson W T Tse, Andrew J Weickhardt, Mehrdad Nikfarjam, Andrew M Scott, Niall C Tebbutt, John M Mariadason
Advanced biliary tract cancer (BTC) has a poor prognosis and limited treatment options. The PI3K/Akt/mTOR signaling pathway is hyperactivated in a subset of BTCs and clinical activity to the mTOR inhibitor everolimus has been observed in some BTC patients. The goal of this study was to identify biomarkers predictive of everolimus response. Twenty BTC cell lines were assessed for everolimus sensitivity with a spectrum of growth inhibitory responses observed. Molecular biomarkers of sensitivity and resistance were identified by interrogation of the activation status of the Ras/MAPK and PI3K/Akt/mTOR pathways...
May 24, 2017: Molecular Oncology
https://www.readbyqxmd.com/read/28544128/a-pediatric-trial-of-radiation-cetuximab-followed-by-irinotecan-cetuximab-in-newly-diagnosed-diffuse-pontine-gliomas-and-high-grade-astrocytomas-a-pediatric-oncology-experimental-therapeutics-investigators-consortium-study
#19
Margaret E Macy, Mark W Kieran, Susan N Chi, Kenneth J Cohen, Tobey J MacDonald, Amy A Smith, Michael M Etzl, Michele C Kuei, Andrew M Donson, Lia Gore, Jennifer DiRenzo, Tanya M Trippett, Irina Ostrovnaya, Aru Narendran, Nicholas K Foreman, Ira J Dunkel
BACKGROUND: Diffuse intrinsic pontine gliomas (DIPGs) and high-grade astrocytomas (HGA) continue to have dismal prognoses. The combination of cetuximab and irinotecan was demonstrated to be safe and tolerable in a previous pediatric phase 1 combination study. We developed this phase 2 trial to investigate the safety and efficacy of cetuximab given with radiation therapy followed by adjuvant cetuximab and irinotecan. METHODS: Eligible patients of age 3-21 years had newly diagnosed DIPG or HGA...
May 24, 2017: Pediatric Blood & Cancer
https://www.readbyqxmd.com/read/28530791/farnesyltransferase-mediated-delivery-of-a-covalent-inhibitor-overcomes-alternative-prenylation-to-mislocalize-k-ras
#20
Christopher J Novotny, Gregory L Hamilton, Frank McCormick, Kevan Shokat
Mutationally activated Ras is one of the most common oncogenic drivers found across all malignancies, and its selective inhibition has long been a goal in both pharma and academia. One of the oldest and most validated methods to inhibit overactive Ras signaling is by interfering with its post-translational processing and subsequent cellular localization. Previous attempts to target Ras processing led to the development of farnesyltransferase inhibitors, which can inhibit H-Ras localization but not K-Ras due to its ability to bypass farnesyltransterase inhibition though alternative prenylation by geranylgeranyltransferase...
May 22, 2017: ACS Chemical Biology
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