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Matthew Dankner, April A N Rose, Shivshankari Rajkumar, Peter M Siegel, Ian R Watson
The RAS-RAF-MEK-ERK signaling cascade is among the most frequently mutated pathways in human cancer. Approximately 50% of melanoma patients possess a druggable hotspot V600E/K mutation in the BRAF protein kinase. FDA-approved combination therapies of BRAF and MEK inhibitors are available that provide survival benefits to patients with a BRAF V600 mutation. Non-V600 BRAF mutants are found in many cancers, and are more prevalent than V600 mutations in certain tumor types. For example, between 50-80% of BRAF mutations in non-small cell lung cancer and 22-30% in colorectal cancer encode for non-V600 mutants...
March 15, 2018: Oncogene
Sandeep S Joshi, Shunlin Jiang, Emmanual Unni, Stephen R Goding, Tao Fan, Paul A Antony, Thomas J Hornyak
Heat shock protein 90 (HSP90) is a molecular chaperone which stabilizes client proteins with important roles in tumor growth. 17-allylamino-17-demethoxygeldanamycin (17-AAG), an inhibitor of HSP90 ATPase activity, occupies the ATP binding site of HSP90 causing a conformational change which destabilizes client proteins and directs them towards proteosomal degradation. Malignant melanomas have active RAF-MEK-ERK signaling which can occur either through an activating mutation in BRAF (BRAFV600E) or through activation of signal transduction upstream of BRAF...
2018: PloS One
Andrew M Kidger, James Sipthorp, Simon J Cook
The RAS-regulated RAF-MEK1/2-ERK1/2 signalling pathway is de-regulated in a variety of cancers due to mutations in receptor tyrosine kinases (RTKs), negative regulators of RAS (such as NF1) and core pathway components themselves (RAS, BRAF, CRAF, MEK1 or MEK2). This has driven the development of a variety of pharmaceutical agents to inhibit RAF-MEK1/2-ERK1/2 signalling in cancer and both RAF and MEK inhibitors are now approved and used in the clinic. There is now much interest in targeting at the level of ERK1/2 for a variety of reasons...
February 15, 2018: Pharmacology & Therapeutics
Hugo Lavoie, Malha Sahmi, Pierre Maisonneuve, Sara A Marullo, Neroshan Thevakumaran, Ting Jin, Igor Kurinov, Frank Sicheri, Marc Therrien
RAF family kinases have prominent roles in cancer. Their activation is dependent on dimerization of their kinase domains, which has emerged as a hindrance for drug development. In mammals, RAF family kinases include three catalytically competent enzymes (ARAF, BRAF and CRAF) and two pseudokinases (KSR1 and KSR2) that have been described as scaffolds owing to their apparent ability to bridge RAF isoforms and their substrate, mitogen-activated protein kinase kinase (MEK). Kinase suppressor of Ras (KSR) pseudokinases were also shown to dimerize with kinase-competent RAFs to stimulate catalysis allosterically...
February 12, 2018: Nature
Gargi Maity, Inamul Haque, Arnab Ghosh, Gopal Dhar, Vijayalaxmi G Gupta, Sandipto Sarkar, Imaan Azeem, Douglas McGregor, Abhishek Choudhary, Donald R Campbell, Suman Kambhampati, Sushanta K Banerjee, Snigdha Banerjee
Myc-associated zinc-finger protein (MAZ) is a transcription factor with dual roles in transcription initiation and termination. Deregulation of MAZ expression is associated with the progression of pancreatic ductal adenocarcinoma (PDAC). However, the mechanism of action of MAZ in PDAC progression is largely unknown. Here, we present evidence that MAZ mRNA expression and protein levels are increased in human PDAC cell lines, tissue samples, a subcutaneous tumor xenograft in a nude mouse model, and spontaneous cancer in the genetically engineered PDAC mouse model...
February 6, 2018: Journal of Biological Chemistry
Issac Horng Khit Too, Isabelle Bonne, Eng Lee Tan, Justin Jang Hann Chu, Sylvie Alonso
A close relative of poliovirus, enterovirus 71 (EV71) is regarded as an important neurotropic virus of serious public health concern. EV71 causes Hand, Foot and Mouth Disease and has been associated with neurological complications in young children. Our limited understanding of the mechanisms involved in its neuropathogenesis has hampered the development of effective therapeutic options. Here, using a two-dimensional proteomics approach combined with mass spectrometry, we have identified a unique panel of host proteins that were differentially and dynamically modulated during EV71 infection of motor-neuron NSC-34 cells, which are found at the neuromuscular junctions where EV71 is believed to enter the central nervous system...
January 2018: PLoS Pathogens
Jeffrey J Heard, Ivy Phung, Mark I Potes, Fuyuhiko Tamanoi
BACKGROUND: RHEB is a unique member of the RAS superfamily of small GTPases expressed in all tissues and conserved from yeast to humans. Early studies on RHEB indicated a possible RHEB-RAF interaction, but this has not been fully explored. Recent work on cancer genome databases has revealed a reoccurring mutation in RHEB at the Tyr35 position, and a recent study points to the oncogenic potential of this mutant that involves activation of RAF/MEK/ERK signaling. These developments prompted us to reassess the significance of RHEB effect on RAF, and to compare mutant and wild type RHEB...
January 10, 2018: BMC Cancer
Sabine Druillennec, Celio Pouponnot, Alain Eychène
Using mouse genetics, we recently showed that BRAF has a critical role in initiation of NRAS-driven melanoma that cannot be compensated by CRAF. In contrast, RAF proteins display compensatory functions in fully established tumors and ARAF can sustain proliferation in the absence of BRAF and CRAF, highlighting an addiction to RAF signaling in NRAS-driven melanoma.
2017: Molecular & Cellular Oncology
Heinz Hammerlindl, Dinoop Ravindran Menon, Sabrina Hammerlindl, Abdullah Al Emran, Joachim Torrano, Katrin Sproesser, Divya Thakkar, Min Xiao, Victoria G Atkinson, Brian Gabrielli, Nikolas K Haass, Meenhard Herlyn, Clemens Krepler, Helmut Schaider
PURPOSE: Identify and characterize novel combinations of sorafenib with anti-inflammatory painkillers to target difficult to treat RAS-mutant cancer. EXPERIMENTAL DESIGN: The cytotoxicity of acetylsalicylic acid (aspirin) in combination with the multikinase inhibitor sorafenib (Nexavar) was assessed in RAS-mutant cell lines in vitro. The underlying mechanism for the increased cytotoxicity was investigated using selective inhibitors and shRNA-mediated gene knockdown...
December 1, 2017: Clinical Cancer Research: An Official Journal of the American Association for Cancer Research
Ryan Thurman, Edhriz Siraliev-Perez, Sharon L Campbell
RAS proteins function as molecular switches that regulate cellular growth by cycling between active GTP- and inactive GDP bound states. While RAS activity is modulated by factors (guanine nucleotide exchange and GTPase activating proteins) that control levels of active Ras-GTP, RAS proteins also undergo a number of post-translational modifications that regulate their function. One such modification is ubiquitylation. Monoubiquitylation of KRAS at lysine 147 (mUbRAS) enhances Ras activation and promotes signaling through the RAF and Phosphoinositide 3-Kinase (PI3K) signaling pathways...
November 29, 2017: Small GTPases
Oscar V Torres, Subramanian Jayanthi, Michael T McCoy, Jean Lud Cadet
Background: The continuing epidemic of methamphetamine (METH) addiction has prompted research aimed at understanding striatal dysfunctions potentially associated with long-term METH use. Methods: Here, we investigated transcriptional and translational alterations in the expression of neurotrophic factors in the rat striatum at 30 days following METH SA and footshock punishment. Male Sprague-Dawley rats were trained to self-administer METH (0.1 mg/kg/injection, i...
November 20, 2017: International Journal of Neuropsychopharmacology
Soni Savai Pullamsetti, Baktybek Kojonazarov, Samantha Storn, Henning Gall, Ylia Salazar, Janine Wolf, Andreas Weigert, Nefertiti El-Nikhely, Hossein Ardeschir Ghofrani, Gabriele A Krombach, Ludger Fink, Stefan Gattenlöhner, Ulf R Rapp, Ralph Theo Schermuly, Friedrich Grimminger, Werner Seeger, Rajkumar Savai
Dyspnea is a frequent, devastating, and poorly understood symptom of advanced lung cancer. In our cohort, among 519 patients who underwent a computed tomography scan for the diagnosis of lung cancer, 250 had a mean pulmonary artery diameter of >28 mm, indicating pulmonary hypertension (PH). In human lung cancer tissue, we consistently observed increased vascular remodeling and perivascular inflammatory cell accumulation (macrophages/lymphocytes). Vascular remodeling, PH, and perivascular inflammatory cell accumulation were mimicked in three mouse models of lung cancer (LLC1, KRas LA2 , and cRaf-BxB )...
November 15, 2017: Science Translational Medicine
Mark Merchant, John Moffat, Gabriele Schaefer, Jocelyn Chan, Xi Wang, Christine Orr, Jason Cheng, Thomas Hunsaker, Lily Shao, Stephanie J Wang, Marie-Claire Wagle, Eva Lin, Peter M Haverty, Sheerin Shahidi-Latham, Hai Ngu, Margaret Solon, Jeffrey Eastham-Anderson, Hartmut Koeppen, Shih-Min A Huang, Jacob Schwarz, Marcia Belvin, Daniel Kirouac, Melissa R Junttila
Mitogen-activated protein kinase (MAPK) pathway dysregulation is implicated in >30% of all cancers, rationalizing the development of RAF, MEK and ERK inhibitors. While BRAF and MEK inhibitors improve BRAF mutant melanoma patient outcomes, these inhibitors had limited success in other MAPK dysregulated tumors, with insufficient pathway suppression and likely pathway reactivation. In this study we show that inhibition of either MEK or ERK alone only transiently inhibits the MAPK pathway due to feedback reactivation...
2017: PloS One
Hezhe Lu, Shujing Liu, Gao Zhang, Bin Wu, Yueyao Zhu, Dennie T Frederick, Yi Hu, Wenqun Zhong, Sergio Randell, Norah Sadek, Wei Zhang, Gang Chen, Chaoran Cheng, Jingwen Zeng, Lawrence W Wu, Jie Zhang, Xiaoming Liu, Wei Xu, Clemens Krepler, Katrin Sproesser, Min Xiao, Benchun Miao, Jianglan Liu, Claire D Song, Jephrey Y Liu, Giorgos C Karakousis, Lynn M Schuchter, Yiling Lu, Gordon Mills, Yusheng Cong, Jonathan Chernoff, Jun Guo, Genevieve M Boland, Ryan J Sullivan, Zhi Wei, Jeffrey Field, Ravi K Amaravadi, Keith T Flaherty, Meenhard Herlyn, Xiaowei Xu, Wei Guo
Targeted BRAF inhibition (BRAFi) and combined BRAF and MEK inhibition (BRAFi and MEKi) therapies have markedly improved the clinical outcomes of patients with metastatic melanoma. Unfortunately, the efficacy of these treatments is often countered by the acquisition of drug resistance. Here we investigated the molecular mechanisms that underlie acquired resistance to BRAFi and to the combined therapy. Consistent with previous studies, we show that resistance to BRAFi is mediated by ERK pathway reactivation. Resistance to the combined therapy, however, is mediated by mechanisms independent of reactivation of ERK in many resistant cell lines and clinical samples...
October 5, 2017: Nature
Amir Noeparast, Erik Teugels, Philippe Giron, Gil Verschelden, Sylvia De Brakeleer, Lore Decoster, Jacques De Grève
Approximately half of BRAF-mutated Non-small cell lung cancers (NSCLCs) harbor a non-V600 BRAF mutation, accounting for ∼40,000 annual deaths worldwide. Recent studies have revealed the benefits of combined targeted therapy with a RAF-inhibitor (Dabrafenib) and a MEK-inhibitor (Trametinib) in treating V600 BRAF mutant cancers, including NSCLC. In contrast, sensitivity of non-V600 BRAF mutations to these inhibitors is not documented. Non-V600 mutations can either increase or impair BRAF kinase activity. However, impaired BRAF kinases can still activate the ERK pathway in a CRAF-dependent manner...
September 1, 2017: Oncotarget
Min Wang, Shan Xu, Huajun Lei, Caolin Wang, Zhen Xiao, Shuang Jia, Jia Zhi, Pengwu Zheng, Wufu Zhu
Four series of Sorafenib derivatives bearing pyrazole scaffold (8a-m, 9a-c, 10a-e and 11a) were synthesized and characterized by NMR and MS. All of the target compounds were evaluated for the cytotoxicity against A549, HepG2, MCF-7, and PC-3 cancer cell lines and some selected compounds were further evaluated for the activity against VEGFR-2/KDR, BRAF, CRAF, c-Met, EGFR and Flt-3 kinases. Compounds 8b and 8i were more active than that of compounds 8h, 9a, especially the IC50 value of compounds 8b on VEGFR-2 kinase was 0...
September 6, 2017: Bioorganic & Medicinal Chemistry
Eleni A Kandaraki, Antonios Chatzigeorgiou, Efstathia Papageorgiou, Christina Piperi, Christos Adamopoulos, Athanasios G Papavassiliou, Michael Koutsilieris, Evanthia Diamanti-Kandarakis
Advanced glycation end products accumulate in the ovarian granulosa-cell layer of women with polycystic ovarian syndrome. Taken that the MAPK/ERK-pathway is a key regulator of oocyte maturation and function, consisting the main pathway used by the gonadotrophic hormones (luteinizing hormone, follicle stimulating hormone) to control ovulation, the present study aims to assess advanced glycation end products' interference into luteinizing hormone-and follicle stimulating hormone-signaling via the MAPK/ERK-pathway in the human granulosa KGN cell line...
January 1, 2017: Experimental Biology and Medicine
Alison M Schram, Matthew T Chang, Philip Jonsson, Alexander Drilon
Structural gene rearrangements resulting in gene fusions are frequent events in solid tumours. The identification of certain activating fusions can aid in the diagnosis and effective treatment of patients with tumours harbouring these alterations. Advances in the techniques used to identify fusions have enabled physicians to detect these alterations in the clinic. Targeted therapies directed at constitutively activated oncogenic tyrosine kinases have proven remarkably effective against cancers with fusions involving ALK, ROS1, or PDGFB, and the efficacy of this approach continues to be explored in malignancies with RET, NTRK1/2/3, FGFR1/2/3, and BRAF/CRAF fusions...
December 2017: Nature Reviews. Clinical Oncology
Adrian Fischer, Wignand W D Mühlhäuser, Bettina Warscheid, Gerald Radziwill
Spatiotemporal control is a common mechanism that modulates activity and function of signal transducers in the signaling network. We identified acetylation of CNK1 (connector enhancer of kinase suppressor of Ras-1) as a late step in the activation of CNK1 signaling, accompanied with prolonged stimulation of extracellular signal-regulated kinase (ERK). We identified the acetyltransferase CREB (cyclic adenosine 3',5'-monophosphate response element-binding protein)-binding protein and the deacetylase SIRT2 (sirtuin type 2) as novel binding partners of CNK1, modulating the acetylation state of CNK1...
August 2017: Science Advances
P Jain, T M Fierst, H J Han, T E Smith, A Vakil, P B Storm, A C Resnick, A J Waanders
Pediatric low-grade gliomas (PLGGs) are commonly associated with BRAF gene fusions that aberrantly activate the mitogen-activated protein kinase (MAPK) signaling pathway. This has led to PLGG clinical trials utilizing RAF- and MAPK pathway-targeted therapeutics. Whole-genome profiling of PLGGs has also identified rare gene fusions involving another RAF isoform, CRAF/RAF1, in PLGGs and cancers occuring in adults. Whereas BRAF fusions primarily dysregulate MAPK signaling, the CRAF fusions QKI-RAF1 and SRGAP3-RAF1 aberrantly activate both the MAPK and phosphoinositide-3 kinase/mammalian target of rapamycin (PI3K/mTOR) signaling pathways...
November 9, 2017: Oncogene
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