Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0006142 (breast cancer)
160,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several short forms of alternatively spliced Murine double minute 2 (MDM2) transcripts have recently been shown to correlate with high-grade malignancy in a number of human tumors. We examined the frequency of splice variants and their correlation with clinicopathological features in 60 cases of human breast cancer. Seven short forms coexpressed with wild-type mRNA were detected by nested RT-PCR. Sequencing of all the MDM2 variants demonstrated mRNA splicing which disrupted not only the conserved p53-binding domain but also, further towards the carboxy-terminus, the conserved nuclear localization sequence and/or the acidic and zinc finger domains. There was no significant correlation between the coexpression of splice variants and tumor size, histologic type or hormone (estrogen and progesterone) receptor status. However, cases with spliced MDM2 transcripts tended to be of a more aggressive type with axillary lymph node involvement and extensive necrosis in the tumors. Although the functional significance of MDM2 variants remains obscure, we anticipate that these variants will be confirmed as a novel prognostic marker in human breast cancer.
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PMID:Alternatively spliced MDM2 transcripts in human breast cancer in relation to tumor necrosis and lymph node involvement. 1110 50

The chemical stability of 207 zinc fingers, derived from 92 experimental protein structures, is evaluated according to the protein packing and electrostatic screening of their zinc cores. These properties are used as measures of the protein protection of zinc cores, to predictively rank relative zinc finger reactivities and assess differences in function. On average, there is a substantial and concomitant increase in the screening of increasingly anionic core motifs, suggesting zinc fingers have evolved in a manner that promotes shielding of their potentially reactive core thiolates. In contrast, enzymatic zinc cores are functionally differentiated by negative electrostatic screening. Zinc finger cores are predominantly screened by networks of backbone:core NH-S hydrogen bonds that electronically stabilize core thiolates and enhance backbone packing. Stabilizing protein:core interactions can be mapped to conserved residues, including [Arg,Lys]:core salt-bridges in some protein families. Labile zinc fingers are identified by poorly screened cores, possibly indicating redox or metallothionein (MT) regulated function. Consistent with experiment, the cores of the C-terminal finger of the human immunodeficiency virus type 1 (HIV-1) nucleocapsid protein p7 (NCp7) and Escherichia coli Ada protein (Ada) "finger" are identified as reactive. The C-terminal zinc fingers of nuclear receptors are predicted to be the most labile in this study, particularly the human estrogen receptor (hER), which contains a triad of reactive thiolates. We propose that hER DNA binding is redox and MT regulated through the C-terminal finger and that weak electrophilic agents may inhibit hER-mediated transcription, implicated in breast cancer progression.
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PMID:Reactivity of zinc finger cores: analysis of protein packing and electrostatic screening. 1145 58

Nuclear hormone receptors (NRs) are transcription factors whose activity is regulated by ligands and by coactivators or corepressors. We report the characterization of a new NR coregulator: proline-, glutamic acid-, leucine-rich protein 1 (PELP1), a novel human protein that comprises 1,282 amino acids and is localized on chromosome 17. The primary structure of PELP1 consists of several motifs present in most transcriptional regulators including nine NR-interacting boxes (LXXLL motifs), a zinc finger, and glutamic acid- and proline-rich regions. We demonstrate that PELP1 is a coactivator of estrogen receptor alpha (ERalpha). PELP1 enhances 17beta-estradiol-dependent transcriptional activation from the estrogen response element in a dose-dependent manner. PELP1 interacts with ERalpha and also with general transcriptional coactivators p300 and cAMP response element-binding protein-binding protein. PELP1 was differentially expressed in various human and murine tissues with the highest expression levels in the testes, mammary glands, and brain. We also provide evidence supporting the developmental regulation of PELP1 expression in murine mammary glands, the detectable expression of PELP1 in human mammary cancer cell lines, and the enhanced expression of PELP1 in human breast tumors. These findings suggest that PELP1 is a novel coregulator of ERalpha and may have a role in breast cancer tumorigenesis.
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PMID:Molecular cloning and characterization of PELP1, a novel human coregulator of estrogen receptor alpha. 1148 23

We have identified and characterized a gene (60% on protein level) and a pseudogene (93% on DNA level) that show high similarity to the Wolf-Hirschhorn syndrome candidate gene-1 (WHSC1). These genes, WHSC1L1 and WHSC1L2P, map to human chromosomes 8p11.2 and 17q21, respectively. WHSC1L1 is ubiquitously expressed and, like WHSC1, generates two major transcripts, a short (s-type) and a long (l-type). The WHSC1L1 l-type transcript encodes a 1437-amino-acid protein containing 2 PWWP (proline-trypto-phan-proline-tryptophan) domains, 5 PHD (plant-home-domain)-type zinc finger motifs, a SAC (SET-associated Cys-rich) domain, and a SET (Suppressor of Variegation, Enhancer of Zeste and Trithorax) domain. The s-type transcript encodes a protein of 645 amino acids containing a PWWP domain only. WHSC1L2P is an unexpressed, intronless pseudogene of a WHSC1L1 s-type transcript. The 8p11.2 region around WHSC1L1 contains a set of genes including TACC1, FGFR1, LETM2, and WHSC1L1, which seems to be derived from a recent duplication involving 4p16.3 where a similar set of genes is located. Rearrangements of 8p are frequently found in human cancer, including breast cancer. These characteristics indicate that WHSC1L1 might have a role in embryonic development and, when disregulated, in cancer development.
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PMID:WHSC1L1, on human chromosome 8p11.2, closely resembles WHSC1 and maps to a duplicated region shared with 4p16.3. 1154 11

The retinoblastoma protein-interacting zinc finger gene RIZ1 is a tumor suppressor gene and a member of a nuclear histone/protein methyltransferase superfamily. RIZ1 inactivation is commonly found in many types of human cancers and occurs through loss of mRNA expression, frameshift mutation, chromosomal deletion, and missense mutation. RIZ1 is also a tumor susceptibility gene in mice. We now show that loss of RIZ1 mRNA in human cancers is associated with DNA methylation of its promoter CpG island. Methylation of the RIZ1 promoter strongly correlated with lost or decreased RIZ1 mRNA expression in breast, liver, colon, and lung cancer cell lines as well as in liver cancer tissues. Treatment with the methylation inhibitor 5-aza-2'-deoxycytidine activated RIZ1 mRNA expression in cancer cells. Furthermore, methylation was found in 11 of 25 (44%) breast cancer specimens and 20 of 32 (62%) liver cancer specimens. Our results suggest that DNA methylation is a common mechanism in inactivating the RIZ1 tumor suppressor gene in human liver and breast cancers.
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PMID:Hypermethylation in human cancers of the RIZ1 tumor suppressor gene, a member of a histone/protein methyltransferase superfamily. 1171 34

Germline mutations in breast cancer susceptibility genes, BRCA1 and BRCA2, are responsible for a substantial proportion of high-risk breast and breast/ovarian cancer families. To characterize the spectrum of BRCA1 and BRCA2 mutations, we screened Czech families with breast/ovarian cancer using the non-radioactive protein truncation test, heteroduplex analysis and direct sequencing. In a group of 100 high-risk breast and breast/ovarian cancer families, four novel frame shift mutations were identified in BRCA1 and BRCA2 genes. In BRCA1, two novel frame shift mutations were identified as 3761-3762delGA and 2616-2617ins10; in BRCA2, two novel frame shift mutations were identified as 5073-5074delCT and 6866delC. Furthermore, a novel missense substitution M18K in BRCA1 gene in a breast/ovarian cancer family was identified which lies adjacent just upstream of the most highly conserved C3HC4 RING zinc finger motif. To examine the tertiary structure of the RING zinc finger domain and possible effects of M18K substitution on its stability, we used threading techniques according to the crystal structure of RAG1 dimerization domain of the DNA-binding protein.
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PMID:Novel germline BRCA1 and BRCA2 mutations in breast and breast/ovarian cancer families from the Czech Republic. 1174 48

Estrogen receptor alpha (ERalpha)/Sp1 activation of GC-rich gene promoters in breast cancer cells is dependent, in part, on activation function 1 (AF1) of ERalpha, and this study investigates contributions of the DNA binding domain (C) and AF2 (DEF) regions of ERalpha on activation of ERalpha/Sp1. 17Beta-estradiol (E2) and the antiestrogens 4-hydroxytamoxifen and ICI 182,780 induced reporter gene activity in MCF-7 and MDA-MB-231 cells cotransfected with human or mouse ERalpha (hERalpha or MOR), but not ERbeta and GC-rich constructs containing three tandem Sp1 binding sites (pSp13) or other E2-responsive GC-rich promoters. Estrogen and antiestrogen activation of hERalpha/Sp1 was dependent on overlapping and different regions of the C, D, E, and F domains of ERalpha. Antiestrogen-induced activation of hERalpha/Sp1 was lost using hERalpha mutants deleted in zinc finger 1 [amino acids (aa) 185-205], zinc finger 2 (aa 218-245), and the hinge/helix 1 (aa 265-330) domains. In contrast with antiestrogens, E2-dependent activation of hERalpha/Sp1 required the C-terminal F domain (aa 579-595), which contains a beta-strand structural motif. Moreover, in peptide competition experiments overexpression of a C-terminal (aa 575-595) F domain peptide specifically blocked E2-dependent activation of hERalpha/Sp1, suggesting that F domain interactions with nuclear cofactors are required for ERalpha/Sp1 action.
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PMID:Domains of estrogen receptor alpha (ERalpha) required for ERalpha/Sp1-mediated activation of GC-rich promoters by estrogens and antiestrogens in breast cancer cells. 1257 90

Human SNAIL1 (SNAI1) protein encoded by SNAI1/SNA gene represses transcription of E-cadherin/CDH1 gene. Human SNAIL2 (SNAI2) protein encoded by SNAI2/SLUG gene induces the first phase of epithelial-mesenchymal transition (EMT), including desmosome dissociation, cell spreading, and initiation of cell separation. Here, we have identified human SNAIL3 (SNAI3) gene using bioinformatics. Human SNAI3 gene, consisting of at least three exons, spans around the nucleotide position 320214-328221 of human reference genomic contig NT_010404.8 in the reverse orientation. SNAI3 gene, was located between KIAA0233 gene and CBFA2T3 gene in human chromosome 16q24.3, a region affected in breast cancer, gastric cancer, hepatocellular carcinoma, ovarian cancer, and therapy-related myeloid leukemia with t(16;21)(q24;q22) translocation. Human SNAI3 gene was found to encode 292-amino-acid polypeptide with the N-terminal SNAG domain and five zinc finger domains. N-terminal SNAG domain was identified in zinc finger proteins SNAI1, SNAI2, SNAI3, SCRATCH (SCRT1), GFI1, and GFI1B. ATP/GTP binding site was identified in SCRT1, GFI1 and GFI1B, but not in SNAI1, SNAI2 and SNAI3. Phylogenetic analysis of human zinc finger proteins with SNAG domain revealed that SNAI1, SNAI2 and SNAI3 were more closely related. These results clearly indicate that SNAI1, SNAI2 and SNAI3 constitute a subfamily among SNAG zinc-finger proteins. Human SNAI3 mRNA was expressed in skin melanotic melanoma, lung epidermoid carcinoma, and germ cell tumor. Because SNAG zinc-finger proteins are transcriptional repressors implicated in carcinogenesis and embryogenesis, SNAI3 gene might be a potent target of pharmacogenomics in the field of oncology and regenerative medicine.
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PMID:Identification and characterization of human SNAIL3 (SNAI3) gene in silico. 1257 45

Desmoplastic small round cell tumor (DSRCT) is defined by a chimeric transcription factor, resulting from fusion of the N-terminal domain of the Ewing's sarcoma gene EWS to the three C-terminal zinc fingers of the Wilms' tumor suppressor WT1. Although DNA-binding sites have been defined for the uninterrupted WT1 zinc finger domains, the most prevalent isoforms of both WT1 and EWS-WT1 have an insertion of three amino acids [lysine, threonine, and serine (KTS)], which abrogates binding to known consensus sequences and transactivation of known target genes. Here, we used cDNA subtractive hybridization to identify an endogenous gene, LRRC15, which is specifically up-regulated after inducible expression of EWS-WT1(+KTS) in cancer cell lines, and is expressed within primary DSRCT cells. The chimeric protein binds in vitro and in vivo to a specific element upstream of LRRC15, leading to dramatic transcriptional activation. Mutagenesis studies define the optimal binding site of the (+KTS) isoform of EWS-WT1 as 5'-GGAGG(A/G)-3'. LRRC15 encodes a leucine-rich transmembrane protein, present at the leading edge of migrating cells, the expression of which in normal tissues is restricted to the invasive cytotrophoblast layer of the placenta; small interfering (siRNA)-mediated suppression of LRRC15 expression in breast cancer cells leads to abrogation of invasiveness in vitro. Together, these observations define the consequence of (KTS) insertion within WT1-derived zinc fingers, and identify a novel EWS-WT1 transcriptional target implicated in tumor invasiveness.
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PMID:Identification of a DNA-binding site and transcriptional target for the EWS-WT1(+KTS) oncoprotein. 1292 58

Current antiestrogen therapy for breast cancer is limited by the mixed estrogenic and antiestrogenic activity of selective estrogen receptor modulators. Here we show that the function of zinc fingers in the estrogen receptor DNA-binding domain (DBD) is susceptible to chemical inhibition by electrophilic disulfide benzamide and benzisothiazolone derivatives, which selectively block binding of the estrogen receptor to its responsive element and subsequent transcription. These compounds also significantly inhibit estrogen-stimulated cell proliferation, markedly reduce tumor mass in nude mice bearing human MCF-7 breast cancer xenografts, and interfere with cell-cycle and apoptosis regulatory gene expression. Functional assays and computational analysis support a molecular mechanism whereby electrophilic agents preferentially disrupt the vulnerable C-terminal zinc finger, thus suppressing estrogen receptor-mediated breast carcinoma progression. Our results provide the proof of principle for a new strategy to inhibit breast cancer at the level of DNA binding, rather than the classical antagonism of estrogen binding.
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PMID:Suppression of breast cancer by chemical modulation of vulnerable zinc fingers in estrogen receptor. 1470 33


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