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Yi-Xin Wu, Jia-Hua Yang, Hirotomo Saitsu
Bortezomib (BTZ), a proteasome inhibitor, is the first proteasome inhibitor to be used in clinical practice. Here we investigated the mechanisms underlying acquired bortezomib resistance in hepatocellular carcinoma (HCC) cells. Using stepwise selection, we established two acquired bortezomib-resistant HCC cell lines, a bortezomib-resistant HepG2 cell line (HepG2/BTZ) and bortezomib-resistant HuH7 cell line (HuH7/BTZ). The 50% inhibitory concentration values of HepG2/BTZ and HuH7/BTZ were respectively 15- and 39-fold higher than those of parental cell lines...
October 18, 2016: Oncotarget
Massimo Nabissi, Maria Beatrice Morelli, Massimo Offidani, Consuelo Amantini, Silvia Gentili, Alessandra Soriani, Claudio Cardinali, Pietro Leoni, Giorgio Santoni
Several studies showed a potential anti-tumor role for cannabinoids, by modulating cell signaling pathways involved in cancer cell proliferation, chemo-resistance and migration. Cannabidiol (CBD) was previously noted in multiple myeloma (MM), both alone and in synergy with the proteasome inhibitor bortezomib, to induce cell death. In other type of human cancers, the combination of CBD with Δ9-tetrahydrocannabinol (THC) was found to act synergistically with other chemotherapeutic drugs suggesting their use in combination therapy...
October 18, 2016: Oncotarget
Li-Qiang Han, Xia Yuan, Xing-Yu Wu, Ri-Dong Li, Bo Xu, Qing Cheng, Zhen-Ming Liu, Tian-Yan Zhou, Hao-Yun An, Xin Wang, Tie-Ming Cheng, Ze-Mei Ge, Jing-Rong Cui, Run-Tao Li
A novel class of urea-containing peptide boronic acids as proteasome inhibitors was designed by introducing a urea scaffold to replace an amido bond. Compounds were synthesized and their antitumor activities were evaluated. After two rounds of optimizations, the compound I-14 was found to be a potent proteasome inhibitor. Compared with Bortezomib, I-14 showed higher potency against the chymotrypsin-like activity of human 20S proteasome (IC50 < 1 pM), similar potency against four different cancer cell lines (IC50 < 10 nM), and better pharmacokinetic profile...
October 14, 2016: European Journal of Medicinal Chemistry
Katharina Grundler, Raffaela Rotter, Sloane Tilley, Joachim Pircher, Thomas Czermak, Mustaf Yakac, Erik Gaitzsch, Steffen Massberg, Florian Krötz, Hae-Young Sohn, Ulrich Pohl, Hanna Mannell, Bjoern F Kraemer
INTRODUCTION: Platelets possess critical hemostatic functions in the system of thrombosis and hemostasis, which can be affected by a multitude of external factors. Previous research has shown that platelets have the capacity to synthesize proteins de novo and more recently a multicatalytic protein complex, the proteasome, has been discovered in platelets. Due to its vital function for cellular integrity, the proteasome has become a therapeutic target for anti-proliferative drug therapies in cancer...
October 13, 2016: Thrombosis Research
Laura de Diego-García, Mercedes Ramírez-Escudero, Álvaro Sebastián-Serrano, Juan Ignacio Diaz-Hernández, Jesús Pintor Just, José J Lucas, Miguel Díaz-Hernández
The Ubiquitin-Proteasome System (UPS) is essential for the regulation of the cellular proteostasis. Indeed, it has been postulated that an UPS dysregulation is the common mechanism that underlies several neurological disorders. Considering that extracellular nucleotides, through their selective P2Y2 receptor (P2Y2R), play a neuroprotective role in various neurological disorders that course with an UPS impairment, we wonder if this neuroprotective capacity resulted from their ability to modulate the UPS. Using a cellular model expressing two different UPS reporters, we found that the stimulation of P2Y2R by its selective agonist Up4U induced a significant reduction of UPS reporter levels...
October 18, 2016: Biochimica et Biophysica Acta
Oznur Bayraktar, Ozlem Oral, Nur Mehpare Kocaturk, Yunus Akkoc, Karin Eberhart, Ali Kosar, Devrim Gozuacik
The ubiquitin-proteasome system (UPS) degrades soluble proteins and small aggregates, whereas macroautophagy (autophagy herein) eliminates larger protein aggregates, tangles and even whole organelles in a lysosome-dependent manner. VCP/p97 was implicated in both pathways. VCP/p97 mutations cause a rare multisystem disease called IBMPFD (Inclusion Body Myopathy with Paget's Disease and Frontotemporal Dementia). Here, we studied the role IBMPFD-related mutants of VCP/p97 in autophagy. In contrast with the wild-type VCP/p97 protein or R155C or R191Q mutants, the P137L mutant was aggregate-prone...
2016: PloS One
Christian Weber, Mikael Koutero, Marie-Agnes Dillies, Hugo Varet, Cesar Lopez-Camarillo, Jean Yves Coppée, Chung-Chau Hon, Nancy Guillén
Amoebiasis is a human infectious disease due to the amoeba parasite Entamoeba histolytica. The disease appears in only 20% of the infections. Diversity in phenotypes may occur within the same infectious strain in the gut; for instance, parasites can be commensal (in the intestinal lumen) or pathogenic (inside the tissue). The degree of pathogenesis of clinical isolates varies greatly. These findings raise the hypothesis that genetic derivation may account for amoebic diverse phenotypes. The main goal of this study was to analyse gene expression changes of a single virulent amoebic strain in different environmental contexts where it exhibit different degrees of virulence, namely isolated from humans and maintained through animal liver passages, in contact with the human colon and short or prolonged in vitro culture...
October 21, 2016: Scientific Reports
Alfredo Lagunas-Martínez, Enrique García-Villa, Magaly Arellano-Gaytán, Carla O Contreras-Ochoa, Jisela Dimas-González, María E López-Arellano, Vicente Madrid-Marina, Patricio Gariglio
The E6 oncoprotein can interfere with the ability of infected cells to undergo programmed cell death through the proteolytic degradation of proapoptotic proteins such as p53, employing the proteasome pathway. Therefore, inactivation of the proteasome through MG132 should restore the activity of several proapoptotic proteins. We investigated whether in HPV16 E6-expressing keratinocytes (KE6 cells), the restoration of p53 levels mediated by MG132 and/or activation of the CD95 pathway through apoptosis antigen-1 (APO-1) antibody are responsible for the induction of apoptosis...
October 20, 2016: Apoptosis: An International Journal on Programmed Cell Death
Yan Long, Wen-Bin Tsai, Jeffrey T Chang, Marcos Estecio, Medhi Wangpaichitr, Naramol Savaraj, Lynn G Feun, Helen H W Chen, Macus Tien Kuo
Many human tumors require extracellular arginine (Arg) for growth because the key enzyme for de novo biosynthesis of Arg, argininosuccinate synthetase 1 (ASS1), is silenced. These tumors are sensitive to Arg-starvation therapy using pegylated arginine deiminase (ADI-PEG20) which digests extracellular Arg. Many previous studies reported that ASS1 silencing is due to epigenetic inactivation of ASS1 expression by DNA methylation, and that the demethylation agent 5-aza-deoxycytidine (Aza-dC) can induce ASS1 expression...
September 28, 2016: Oncotarget
Bingxian Yang, Qijie Guan, Jingkui Tian, Setsuko Komatsu
: High level of UV-B irradiation followed by dark treatment (HUV-B+D) causes accumulation of secondary metabolites in Clematis terniflora DC. To investigate the response mechanism under HUV-B+D, transcriptomic and proteomic analyses were performed in leaves of C. terniflora. The number of genes related to tetrapyrrole synthesis, amino acid metabolism, tricarboxylic acid cycle, and mitochondrial electron transport chains was hierarchically changed in leaves of C. terniflora under HUV-B+D...
October 17, 2016: Journal of Proteomics
Jiankang Zhang, Lixin Gao, Jianjun Xi, Li Sheng, Yanmei Zhao, Lei Xu, Yidan Shao, Shourong Liu, Rangxiao Zhuang, Yubo Zhou, Jia Li
A series of novel non-covalent piperidine-containing dipeptidyl derivatives were designed, synthesized and evaluated as proteasome inhibitors. All target compounds were tested for their proteasome chymotrypsin-like inhibitory activities, and selected derivatives were evaluated for the anti-proliferation activities against two multiple myeloma (MM) cell lines RPMI 8226 and MM-1S. Among all of these compounds, eight exhibited significant proteasome inhibitory activities with IC50 less than 20nM, and four are more potent than the positive control Carfilzomib...
October 6, 2016: Bioorganic & Medicinal Chemistry
Chiung-Mei Chen, I-Cheng Chen, Ying-Lin Chen, Te-Hsien Lin, Wan-Ling Chen, Chih-Ying Chao, Yih-Ru Wu, Yeah-Ting Lu, Cheng-Yu Lee, Hong-Chi Chien, Ting-Shou Chen, Guey-Jen Lee-Chen, Chi-Mei Lee
BACKGROUND: The F-box protein 7 (FBXO7) mutations have been identified in families with early-onset parkinsonism and pyramidal tract signs, and designated as PARK15. In addition, FBXO7 mutations were found in typical and young onset Parkinson's disease (PD). Evidence has also shown that FBXO7 plays an important role in the development of dopaminergic neurons and increased stability and overexpression of FBXO7 may be beneficial to PD. PURPOSE: We screened extracts of medicinal herbs to enhance FBXO7 expression for neuroprotection in MPP(+)-treated cells...
November 15, 2016: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
Yoo Seob Shin, Sung Un Kang, Ju Kyeong Park, Yang Eun Kim, Yeon Soo Kim, Seung Joon Baek, Seong-Ho Lee, Chul-Ho Kim
BACKGROUND AND PURPOSE: Aberrant expression of β-catenin is highly associated with progression of various cancers including head and neck cancer (HNC). Green tea is most commonly used beverage in the world and one of the more bioactive compounds is the antioxidant epigallocatechin gallate (EGCG). This study was performed to investigate the mechanism by which EGCG inhibits the growth of HNC, focusing on the modulation of the expression and activity of β-catenin. METHODS: In vitro effects of EGCG on the transcription, translation, or degradation of β-catenin were investigated...
November 15, 2016: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
Sagrario Martín-Aragón, Karim Lizeth Jiménez-Aliaga, Juana Benedí, Paloma Bermejo-Bescós
BACKGROUND: Plant secondary metabolites may induce adaptive cellular stress-responses in a variety of cells including neurons at the sub-toxic doses ingested by humans. Such 'neurohormesis' phenomenon, activated by flavonoids such as quercetin or rutin, may involve cell responses driven by modulation of signaling pathways which are responsible for its neuroprotective effects. PURPOSE: We attempt to explore the molecular mechanisms involved in the neurohormetic responses to quercetin and rutin exposure, in a SH-SY5Y cell line which stably overexpresses the amyloid precursor protein (APP) Swedish mutation, based on a biphasic concentration-response relationship for cell viability...
November 15, 2016: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
Marc A Becker, Xiaonan Hou, Piyawan Tienchaianada, Brian B Haines, Sean C Harrington, S John Weroha, Sriram Sathyanarayanan, Paul Haluska
BACKGROUND: Mammalian target of rapamycin (mTOR) represents a key downstream intermediate for a myriad of oncogenic receptor tyrosine kinases. In the case of the insulin-like growth factor (IGF) pathway, the mTOR complex (mTORC1) mediates IGF-1 receptor (IGF-1R)-induced estrogen receptor alpha (ERα) phosphorylation/activation and leads to increased proliferation and growth in breast cancer cells. As a result, the prevalence of mTOR inhibitors combined with hormonal therapy has increased in recent years...
October 20, 2016: BMC Cancer
Ariel Lewis-Ballester, Farhad Forouhar, Sung-Mi Kim, Scott Lew, YongQiang Wang, Shay Karkashon, Jayaraman Seetharaman, Dipanwita Batabyal, Bing-Yu Chiang, Munif Hussain, Maria Almira Correia, Syun-Ru Yeh, Liang Tong
Tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO) play a central role in tryptophan metabolism and are involved in many cellular and disease processes. Here we report the crystal structure of human TDO (hTDO) in a ternary complex with the substrates L-Trp and O2 and in a binary complex with the product N-formylkynurenine (NFK), defining for the first time the binding modes of both substrates and the product of this enzyme. The structure indicates that the dioxygenation reaction is initiated by a direct attack of O2 on the C2 atom of the L-Trp indole ring...
October 20, 2016: Scientific Reports
Jan Hagenbucher, Hilda Stekman, Alfonso Rodriguez-Gil, Michael Kracht, M Lienhard Schmitz
The family of seven-in-absentia (SIAH) ubiquitin E3 ligases functions in the control of numerous key signaling pathways. These enzymes belong to the RING (really interesting new gene) group of E3 ligases and mediate the attachment of ubiquitin chains to substrates, which then leads to their proteasomal degradation. Here, we describe a protocol that allows measuring SIAH-mediated ubiquitination and degradation of its client proteins as exemplified by acetyl transferases using simple overexpression experiments...
2017: Methods in Molecular Biology
Alberto Campanaro, Raffaella Battaglia, Massimo Galbiati, Ari Sadanandom, Chiara Tonelli, Lucio Conti
SUMOylation and anther growth. During fertilization, stamen elongation needs to be synchronized with pistil growth. The phytohormone gibberellic acid (GA) promotes stamen growth by stimulating the degradation of growth repressing DELLA proteins. DELLA accumulation is negatively regulated by GAs through the ubiquitin-proteasome system. In Arabidopsis thaliana, a proportion of DELLAs is also conjugated to the small ubiquitin-like modifier (SUMO) protein, which stabilizes DELLAs. Increased DELLA levels occur in the SUMO protease-deficient OVERLY TOLERANT TO SALT 1 and 2 (ots1 ots2) double mutants, especially under salt stress conditions...
October 19, 2016: Plant Reproduction
Takehito Kondo, Ichiro Hisatome, Shouichi Yoshimura, Endang Mahati, Tomomi Notsu, Peili Li, Kazuhiko Iitsuka, Masaru Kato, Kazuyoshi Ogura, Junichiro Miake, Takeshi Aiba, Wataru Shimizu, Yasutaka Kurata, Shinji Sakata, Naoe Nakasone, Haruaki Ninomiya, Akira Nakai, Katsumi Higaki, Yasushi Kawata, Yasuaki Shirayoshi, Akio Yoshida, Kazuhiro Yamamoto
BACKGROUND: The human ether-a-go-go-related gene (HERG) encodes the α-subunit of rapidly activating delayed-rectifier potassium channels. Mutations in this gene cause long QT syndrome type 2 (LQT2). In most cases, mutations reduce the stability of the channel protein, which can be restored by heat shock (HS). METHODS: We identified the novel mutant A78T-HERG in a patient with LQT2. The purpose of the current study was to characterize this mutant protein and test whether HS and heat shock factors (HSFs) could stabilize the mutant protein...
October 2016: Journal of Arrhythmia
Valeria Lanza, Alessio Travaglia, Gaetano Malgieri, Roberto Fattorusso, Giuseppe Grasso, Giuseppe Di Natale, Valeria Zito, Giuseppe Arena, Danilo Milardi, Enrico Rizzarelli
Many biochemical pathways involving nerve growth factor (NGF), a neurotrophin with copper(II) binding abilities, are regulated by the ubiquitin (Ub) proteasome system. However, whether NGF binds Ub and the role played by copper(II) ions in modulating their interactions have not yet been investigated. Herein NMR spectroscopy, circular dichroism, ESI-MS, and titration calorimetry are employed to characterize the interactions of NGF with Ub. NGF1-14 , which is a short model peptide encompassing the first 14 N-terminal residues of NGF, binds the copper-binding regions of Ub (KD =8...
October 19, 2016: Chemistry: a European Journal
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