Search results for "Tumor suppressor"
showing 10 items of 401 documents
Wip1 phosphatase: between p53 and MAPK kinases pathways.
2016
IF 5.008; International audience; Cells undergoing oncogenic transformation frequently inactivate tumor suppressor pathways that could prevent their uncontrolled growth. Among those pathways p53 and p38MAPK pathways play a critical role in regulation of cell cycle, senescence and cell death in response to activation of oncogenes, stress and DNA damage. Consequently, these two pathways are important in determining the sensitivity of tumor cells to anti-cancer treatment. Wild type p53-induced phosphatase, Wip1, is involved in governance of both pathways. Recently, strategies directed to manipulation with Wip1 activity proposed to advance current day anticancer treatment and novel chemical com…
Endogenous Myoglobin in Breast Cancer Is Hypoxia-inducible by Alternative Transcription and Functions to Impair Mitochondrial Activity
2011
Recently, immunohistochemical analysis of myoglobin (MB) in human breast cancer specimens has revealed a surprisingly widespread expression of MB in this nonmuscle context. The positive correlation with hypoxia-inducible factor 2α (HIF-2α) and carbonic anhydrase IX suggested that oxygen regulates myoglobin expression in breast carcinomas. Here, we report that MB mRNA and protein levels are robustly induced by prolonged hypoxia in breast cancer cell lines, in part via HIF-1/2-dependent transactivation. The hypoxia-induced MB mRNA originated from a novel alternative transcription start site 6 kb upstream of the ATG codon. MB regulation in normal and tumor tissue may thus be fundamentally diff…
Cytotoxicity of 35 medicinal plants from Sudan towards sensitive and multidrug-resistant cancer cells
2015
Abstract Background Cancer is a complex disease with multiple genetic and epigenetic alterations. Since decades, the hallmark of cancer therapy is chemotherapy. Cytotoxic drugs erase rapidly dividing cells without sufficient differentiation between normal and cancerous cells resulting in severe side effects in normal tissues. Recently, strategies for cancer treatment focused on targeting specific proteins involved in tumor growth and progression. The present study was designed to investigate the cytotoxicity of 65 crude extracts from 35 Sudanese medicinal plants towards various cancer cell lines expressing molecular mechanisms of resistance towards classical chemotherapeutics (two ATP-bindi…
Putative molecular determinants mediating sensitivity or resistance towards carnosic acid tumor cell responses.
2020
Abstract Background Carnosic acid (CA) is one of the main constituents in rosemary extract. It possesses valuable pharmacological properties, including anti-oxidant, anti-inflammatory, anti-microbial and anti-cancer activities. Numerous in vitro and in vivo studies investigated the anticancer profile of CA and emphasized its potentiality for cancer treatment. Nevertheless, the role of multidrug-resistance (MDR) related mechanisms for CA's anticancer effect is not yet known. Purpose We investigated the cytotoxicity of CA against known mechanisms of anticancer drug resistance (P-gp, ABCB5, BCRP, EGFR and p53) and determined novel putative molecular factors associated with cellular response to…
Cytotoxicity of the indole alkaloid reserpine from Rauwolfia serpentina against drug-resistant tumor cells.
2015
Abstract Background: The antihypertensive reserpine is an indole alkaloid from Rauwolfia serpentina and exerts also profound activity against cancer cells in vitro and in vivo. The present investigation was undertaken to investigate possible modes of action to explain its activity toward drug-resistant tumor cells. Material and methods: Sensitive and drug-resistant tumor cell lines overexpressing P-glycoprotein (ABCB1/MDR1), breast cancer resistance protein (ABCG2/BCRP), mutation-activated epidermal growth factor receptor (EGFR), wild-type and p53-knockout cells as well as the NCI panel of cell lines from different tumor origin were analyzed. Reserpine's cytotoxicity was investigated by res…
Pharmacogenomic Characterization of Cytotoxic Compounds from Salvia officinalis in Cancer Cells.
2015
Salvia officinalis is used as a dietary supplement with diverse medicinal activity (e.g. antidiabetic and antiatherosclerotic effects). The plant also exerts profound cytotoxicity toward cancer cells. Here, we investigated possible modes of action to explain its activity toward drug-resistant tumor cells. Log10IC50 values of two constituents of S. officinalis (ursolic acid, pomolic acid) were correlated to the expression of ATP-binding cassette (ABC) transporters (P-glycoprotein/ABCB1/MDR1, MRP1/ABCC1, BCRP/ABCG2) and epidermal growth factor receptor (EGFR) or mutations in RAS oncogenes and the tumor suppressor gene TP53 of the NCI panel of cell lines. Gene expression profiles predicting se…
Cytotoxicity of cucurbitacin E from Citrullus colocynthis against multidrug-resistant cancer cells
2019
Abstract Background Cucurbitacin E (CuE) is an oxygenated tetracyclic triterpenoid isolated from the fruits of Citrullus colocynthis (L.) Schrad. Purpose This study outlines CuE's cytotoxic activity against drug-resistant tumor cell lines. Three members of ABC transporters superfamily, P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and ABCB5 were investigated, whose overexpression in tumors is tightly linked to multidrug resistance. Further factors of drug resistance studied were the tumor suppressor TP53 and the epidermal growth factor receptor (EGFR). Methods Cytotoxicity assays (resazurin assays) were used to investigate the activity of Citrullus colocynthis and CuE towar…
TP53 and p16INK4A, but not H-KI-Ras, are involved in tumorigenesis and progression of pleomorphic adenomas.
2006
The putative role of TP53 and p16INK4A tumor suppressor genes and Ras oncogenes in the development and progression of salivary gland neoplasias was studied in 28 cases of pleomorphic adenomas (PA), 4 cases of cystic adenocarcinomas, and 1 case of carcinoma ex-PA. Genetic and epigenetic alterations in the above genes were analyzed by Polymerase Chain Reaction/Single Strand Conformational Polymorphism (PCR/SSCP) and sequencing and by Methylation Specific-PCR (MS-PCR). Mutations in TP53 were found in 14% (4/28) of PAs and in 60% (3/5) of carcinomas. Mutations in H-Ras and K-Ras were identified in4%(1/28) and7% (2/28) of PAs, respectively. Only 20% (1/5) of carcinomas screened displayed mutatio…
CAF-like state in primary skin fibroblasts with constitutional BRCA1 epimutation sheds new light on tumor suppressor deficiency-related changes in he…
2016
Constitutive epimutations of tumor suppressor genes are increasingly considered as cancer predisposing factors equally to sequence mutations. In light of the emerging role of the microenvironment for cancer predisposition, initiation, and progression, we aimed to characterize the consequences of a BRCA1 epimutation in cells of mesenchymal origin. We performed a comprehensive molecular and cellular comparison of primary dermal fibroblasts taken from a monozygous twin pair discordant for recurrent cancers and BRCA1 epimutation, whose exceptional clinical case we previously reported in this journal. Comparative transcriptome analysis identified differential expression of extracellular matrix-r…
A recurrent TP63 mutation causing EEC3 and Rapp–Hodgkin syndromes
2016
The ectrodactyly, ectodermal dysplasia, and cleft lip/palate syndrome 3 (EEC3; OMIM #604292), the Rapp-Hodgkin syndrome (RHS), and various other syndromes are caused by mutations in the TP63 gene, which encodes a p53-like transcription factor. Here, we report on a woman aged 37 years and her daughter aged 3 years with the previously reported c.1028G>A (p.Arg343Gln) mutation in exon 8 of TP63. The mother lacked ectrodactyly, indicating a diagnosis of RHS, whereas the girl presented with all three major features (ectrodactyly, ectodermal dysplasia, clefting) and different minor features (including small and brittle nails, and recurrent conjunctivitis believed to be because of stenotic and blo…