Read by QxMD icon Read

p53 mutant

Alejandro Parrales, Atul Ranjan, Swathi V Iyer, Subhash Padhye, Scott J Weir, Anuradha Roy, Tomoo Iwakuma
Stabilization of mutant p53 (mutp53) in tumours greatly contributes to malignant progression. However, little is known about the underlying mechanisms and therapeutic approaches to destabilize mutp53. Here, through high-throughput screening we identify statins, cholesterol-lowering drugs, as degradation inducers for conformational or misfolded p53 mutants with minimal effects on wild-type p53 (wtp53) and DNA contact mutants. Statins preferentially suppress mutp53-expressing cancer cell growth. Specific reduction of mevalonate-5-phosphate by statins or mevalonate kinase knockdown induces CHIP ubiquitin ligase-mediated nuclear export, ubiquitylation, and degradation of mutp53 by impairing interaction of mutp53 with DNAJA1, a Hsp40 family member...
October 24, 2016: Nature Cell Biology
Atanu Das, Dmitrii E Makarov
Protein aggregation and amyloid formation are implicated in many diseases as well as in other biological phenomena. Recent studies have suggested that amyloid formation of tumor suppressor p53 can lead to loss of its physiological function, resulting in accelerated cancer progression. Design of cancer therapeutics, therefore, requires understanding of the mechanism of p53 aggregation. Here, we have employed atomistic simulations to characterize the aggregation process of the aggregation-prone (as suggested by experimental studies) p53 fragment (LTIITLE, 252-258) and to assess the efficiency of its I254R mutant as an aggregation suppressor...
October 24, 2016: Journal of Physical Chemistry. B
John F Dankert, Gergely Rona, Linda Clijsters, Phillip Geter, Jeffrey R Skaar, Keria Bermudez-Hernandez, Elizabeth Sassani, David Fenyö, Beatrix Ueberheide, Robert Schneider, Michele Pagano
SLBP (stem-loop binding protein) is a highly conserved factor necessary for the processing, translation, and degradation of H2AFX and canonical histone mRNAs. We identified the F-box protein cyclin F, a substrate recognition subunit of an SCF (Skp1-Cul1-F-box protein) complex, as the G2 ubiquitin ligase for SLBP. SLBP interacts with cyclin F via an atypical CY motif, and mutation of this motif prevents SLBP degradation in G2. Expression of an SLBP stable mutant results in increased loading of H2AFX mRNA onto polyribosomes, resulting in increased expression of H2A...
September 24, 2016: Molecular Cell
Haiying Chen, Hongli Yang, Hongmei Yue, Pádraig Michael Strappe, Peng Xia, Li Pan, Yingxin Zhang, Shoudong Chai, Shuangfeng Chen, Longle Ma, Lexin Wang
BACKGROUND: This study aimed to investigate the effect of bone marrow derived mesenchymal stem cells (rBMSCs) transduced with lentiviral vectors expressing endothelial nitric oxide synthase (eNOS) and/or a mutant caveolin-1(F92A-Cav1), on the pulmonary haemodynamics and structure in a rat model of pulmonary arterial hypertension (PAH). METHODS: Pulmonary arterial hypertension was induced with monocrotaline (MCT) in 60 adult male Wistar rats prior to delivery of lentiviral vector transduced rBMSCs expressing Cav1, eNOS and/or F92A-Cav1...
September 9, 2016: Heart, Lung & Circulation
Vinicius Duarte Cabral, Marcelle Reesink Cerski, Ivana Trindade Sa Brito, Lucia Maria Kliemann
BACKGROUND: Abnormalities in tumor suppressors p14, p16 and p53 are reported in several human cancers. In ovarian epithelial carcinogenesis, p16 and p53 show higher immunohistochemical staining frequencies in malignant tumors and are associated with poor prognoses. p14 was only analyzed in carcinomas, with conflicting results. There are no reports on its expression in benign and borderline tumors. This study aims to determine p14, p16 and p53 expression frequencies in ovarian benign, borderline and malignant tumors and their associations with clinical parameters...
October 22, 2016: Journal of Ovarian Research
Deepak Adhikari, Kiran Busayavalasa, Jingjing Zhang, Mengwen Hu, Sanjiv Risal, Mustafa Bilal Bayazit, Meenakshi Singh, M Kasim Diril, Philipp Kaldis, Kui Liu
A unique feature of female germ cell development in mammals is their remarkably long arrest at the prophase of meiosis I, which lasts up to 50 years in humans. Both dormant and growing oocytes are arrested at prophase I and completely lack the ability to resume meiosis. Here, we show that the prolonged meiotic arrest of female germ cells is largely achieved via the inhibitory phosphorylation of Cdk1 (cyclin-dependent kinase 1). In two mouse models where we have introduced mutant Cdk1(T14AY15F) which cannot be inhibited by phosphorylation (Cdk1AF) in small meiotically incompetent oocytes, the prophase I arrest is interrupted, leading to a premature loss of female germ cells...
October 21, 2016: Cell Research
Cheol Keun Park, Ji Soo Park, Hyo Song Kim, Sun Young Rha, Woo Jin Hyung, Jae-Ho Cheong, Sung Hoon Noh, Sang Kil Lee, Yong Chan Lee, Yong-Min Huh, Hyunki Kim
Although targeted therapy for receptor tyrosine kinases (RTKs) of advanced gastric cancers (AGCs) has been in the spotlight, guidelines for the identification of RTK-amplified gastric cancers (RA-GCs) have not been established. In this study, we investigate clinicopathologic characteristics of RA-GCs and propose a screening algorithm for their identification. We performed immunohistochemistry (IHC) for MLH1, MSH2, PMS2, MSH6, key RTKs (EGFR, HER2, MET), and p53, in situ hybridization for Epstein-Barr virus encoding RNA, and silver in situ hybridization (SISH) for EGFR, HER2, and MET using tissue microarrays of 993 AGCs...
September 27, 2016: Oncotarget
Chae Lim Jung, Hyemin Mun, Se-Young Jo, Ju-Hee Oh, ChuHee Lee, Eun-Kyung Choi, Se Jin Jang, Young-Ah Suh
Mutation of p53 occasionally results in a gain of function, which promotes tumor growth. We asked whether destabilizing the gain-of-function protein would kill tumor cells. Downregulation of the gene reduced cell proliferation in p53-mutant cells, but not in p53-null cells, indicating that the former depended on the mutant protein for survival. Moreover, phenformin and 2-deoxyglucose suppressed cell growth and simultaneously destabilized mutant p53. The AMPK pathway, MAPK pathway, chaperone proteins and ubiquitination all contributed to this process...
October 19, 2016: Oncotarget
X W Yuan, X F Huang, Z X Chen, S G Liang, W M Liao
Objective: To investigate the effect of IFNα on doxorubicin-induced apoptosis in human osteosarcoma cells with its molecular mechanisms to provide evidences for improving the treatment of osteosarcoma. Methods: Osteosacoma U2OS and MG63 cells were treated with IFNα and Doxorubicin, alone or in combination, for 72 h . Cytotoxicity was determined with MTT. Apoptosis was evaluated through fluorescence-activated cell sorting, Hoechst33258 staining and DNA ladder assay. The expression of p53, Bax, Bcl-2, Mdm2, p21, caspase-3 and PARP was determined with Western blot...
October 11, 2016: Zhonghua Yi Xue za Zhi [Chinese medical journal]
Raffaella Sordella, Nitin H Shirole, Debjani Pal, Edward R Kastenhuber, Serif Senturk, Joseph Boroda, Paola Pisterzi, Madison Miller, Gustavo Munoz, Marko Anderluh, Marc Ladanyi, Scott W Lowe
TP53 truncating mutations are common in human tumors and are thought to give rise to p53-null alleles. Here, we show that TP53 exon-6 truncating mutations occur at higher than expected frequencies and produce proteins that lack canonical p53 tumor suppressor activities but promote cancer cell proliferation, survival, and metastasis. Functionally and molecularly, these p53 mutants resemble the naturally occurring alternative p53 splice variant, p53-psi. Accordingly, these mutants can localize to mitochondria where they promote tumor phenotypes by binding and activating the mitochondria inner pore permeability regulator, Cyclophilin D (CypD)...
October 19, 2016: ELife
Songjia Lu, Chunhui Cai, Gonghong Yan, Zhuan Zhou, Yong Wan, Vicky Chen, Lujia Chen, Gregory F Cooper, Lina M Obeid, Yusuf A Hannun, Adrian V Lee, Xinghua Lu
Defining processes that are synthetic lethal with p53 mutations in cancer cells may reveal possible therapeutic strategies. In this study, we report the development of a signal-oriented computational framework for cancer pathway discovery in this context. We applied our bipartite-graph-based functional module discovery algorithm to identify transcriptomic modules abnormally expressed in multiple tumors, such that the genes in a module were likely regulated by a common, perturbed signal. For each transcriptomic module, we applied our weighted k-path merge algorithm to search for a set of somatic genome alterations (SGA) that likely perturbed the signal, i...
October 10, 2016: Cancer Research
Shigeo Ohba, Joydeep Mukherjee, Tor-Christian Johannessen, Andrew Mancini, Tracy T Chow, Matthew Wood, Lindsey Jones, Tali Mazor, Roxanne E Marshall, Pavithra Viswanath, Kyle M Walsh, Arie Perry, Robert J A Bell, Joanna J Phillips, Joseph F Costello, Sabrina M Ronen, Russell O Pieper
Mutations in the isocitrate dehydrogenase gene IDH1 are common in lower-grade glioma where they result in the production of 2-hydroxyglutarate (2HG), disrupted patterns of histone methylation and gliomagenesis. IDH1 mutations also co-segregate with mutations in the ATRX gene and the TERT promoter, suggesting that IDH mutation may drive the creation or selection of telomere-stabilizing events as part of immortalization/transformation process. To determine if and how this may occur, we investigated the phenotype of pRb/p53-deficient human astrocytes engineered with IDH1 wild-type (WT) or R132H mutant (IDH1mut) genes as they progressed through their lifespan...
October 6, 2016: Cancer Research
Wensheng Zhang, Erik K Flemington, Kun Zhang
Most cancers are driven by somatic mutations in proto-oncogenes and tumor suppressor genes. Genetic changes in a tumor may accumulate in the tissue self-renewal phase prior to neoplasm. The risk of sporadic mutations increases with age. In this regard, a positive association between patient age and the accumulated mutation burden in tumors exists for many cancer types. However, the reported lines of evidence for such a connection are still limited. TP53 is the most frequently mutated cancer gene. The encoded p53 protein plays crucial roles in DNA repair...
September 2016: Cancer Genetics
Ting Ni, Xiao-Yan Li, Na Lu, Teng An, Zhi-Ping Liu, Rong Fu, Wen-Cong Lv, Yi-Wei Zhang, Xiao-Jun Xu, R Grant Rowe, Yong-Shun Lin, Amanda Scherer, Tamar Feinberg, Xiao-Qi Zheng, Bao-An Chen, X Shirley Liu, Qing-Long Guo, Zhao-Qiu Wu, Stephen J Weiss
The zinc-finger transcription factor Snail1 is inappropriately expressed in breast cancer and associated with poor prognosis. While interrogating human databases, we uncovered marked decreases in relapse-free survival of breast cancer patients expressing high Snail1 levels in tandem with wild-type, but not mutant, p53. Using a Snail1 conditional knockout model of mouse breast cancer that maintains wild-type p53, we find that Snail1 plays an essential role in tumour progression by controlling the expansion and activity of tumour-initiating cells in preneoplastic glands and established tumours, whereas it is not required for normal mammary development...
October 17, 2016: Nature Cell Biology
Su Jung Hwang, Hyeung-Geun Park, Yohan Park, Hyo-Jong Lee
Previously, we reported that α-quaternary chiral lactam derivatives have broad spectrum anticancer activity. However, the underlying molecular mechanisms and its relevance are largely unknown. In the present study, we report progress on α-quaternary chiral lactam analogues that address this, focusing on the novel analogue YH-304 as a candidate to broadly target human cancer cells. The effect of YH-304 on cell transformation was assessed by clonogenic assay in non-small cell lung cancer cells (NSCLCs) A549 and 226B...
October 11, 2016: International Journal of Oncology
Prabhu Thirusangu, V Vigneshwaran, T Prashanth, B R Vijay Avin, Vikas H Malojirao, H Rakesh, Shaukath Ara Khanum, Riaz Mahmood, B T Prabhakar
Hypoxia is a feature of all solid tumours, contributing to tumour progression. Activation of HIF-1α plays a critical role in promoting tumour angiogenesis and metastasis. Since its expression is positively correlated with poor prognosis for cancer patients, HIF-1α is one of the most convincing anticancer targets. BP-1T is a novel antiproliferative agent with promising antiangiogenic effects. In the present study, the molecular mechanism underlying cytotoxic/antiangiogenic effects of BP-1T on tumour/non-tumour angiogenesis was evaluated...
October 14, 2016: Angiogenesis
Jessica Woodward, Gillian C Taylor, Dinesh C Soares, Shelagh Boyle, Daoud Sie, David Read, Keerthi Chathoth, Milica Vukovic, Nuria Tarrats, David Jamieson, Kirsteen J Campbell, Karen Blyth, Juan Carlos Acosta, Bauke Ylstra, Mark J Arends, Kamil R Kranc, Andrew P Jackson, Wendy A Bickmore, Andrew J Wood
Chromosomal instability is a hallmark of cancer, but mitotic regulators are rarely mutated in tumors. Mutations in the condensin complexes, which restructure chromosomes to facilitate segregation during mitosis, are significantly enriched in cancer genomes, but experimental evidence implicating condensin dysfunction in tumorigenesis is lacking. We report that mice inheriting missense mutations in a condensin II subunit (Caph2(nes)) develop T-cell lymphoma. Before tumors develop, we found that the same Caph2 mutation impairs ploidy maintenance to a different extent in different hematopoietic cell types, with ploidy most severely perturbed at the CD4(+)CD8(+) T-cell stage from which tumors initiate...
October 13, 2016: Genes & Development
Wen-Bin Ou, Minmin Lu, Grant Eilers, Hailong Li, Jiongyan Ding, Xuli Meng, Yuehong Wu, Quan He, Qing Sheng, Hai-Meng Zhou, Jonathan A Fletcher
BACKGROUND: Improved mesothelioma patient survival will require development of novel and more effective pharmacological interventions. TP53 genomic mutations are uncommon in mesothelioma, and recent data indicate that p53 remains functional, and therefore is a potential therapeutic target in these cancers. In addition, the tumour suppressor NF2 is inactivated by genomic mechanisms in more than 80% of mesothelioma, causing upregulation of FAK activity. Because FAK is a negative regulator of p53, NF2 regulation of FAK-p53-MDM2 signalling loops were evaluated...
October 13, 2016: British Journal of Cancer
Ha Young Woo, Yoon Sung Bae, Jie-Hyun Kim, Sang Kil Lee, Yong Chan Lee, Jae-Ho Cheong, Sung Hoon Noh, Hyunki Kim
BACKGROUND: Gastric "crawling-type" adenocarcinoma (CRA) is a tumor histologically characterized by irregularly fused glands with low-grade cellular atypia that tends to spread laterally in the mucosa. To date, the expression characteristics of the key molecules involved in CRA, including receptor tyrosine kinases (RTKs), mismatch repair (MMR) proteins, phosphatase and tensin homolog (PTEN), as well as the Epstein-Barr virus (EBV) status, have yet to be uncovered. METHODS: We constructed tissue microarrays of 94 CRAs, 72 conventional-type differentiated adenocarcinomas (CDAs), and 71 intramucosal poorly cohesive adenocarcinomas (PCAs) from early gastric cancers to evaluate and compare the pathological and expression profiles of potential key molecules for molecular classification (EBV; four MMR proteins-MLH1, MSH2, PMS2, and MSH6; three RTKs-HER2, MET, and EGFR; PTEN; and p53)...
October 12, 2016: Gastric Cancer
Chen Hongbo, Duo Yanhong, Hu Bo, Wang Zhiwei, Zhang Fang, Tsai Hsiangi, Zhang Jianping, Zhou Lanzhen, Wang Lijun, Wang Xinyu, Huang Laiqiang
PICT-1 was originally identified as a tumor suppressor. Here, we found that PICT-1 overexpression triggered pro-death autophagy without nucleolar disruption or p53 accumulation in U251 and MCF7 cells. Truncated PICT-1 fragments 181-346 and 1-346, which partly or totally lack nucleolar localization, showed weaker autophagy-inducing effects than full-length PICT-1 and a well-defined nucleolar mutant (181-479). Furthermore, PICT-1 partly localizes to the nucleolar fibrillar center (FC) and directly binds to ribosomal DNA (rDNA) gene loci, where it interacts with upstream binding factor (UBF)...
September 27, 2016: Oncotarget
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"