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)

Survivin, a member of the inhibitory apoptosis protein family, gives rise, by an alternative splicing, to four variants with different functions. Many experimental studies indicate that p53 can regulate the expression of survivin and some of its splice variants. Although both the expression of survivin splice variants and the p53 gene were frequently altered in human cancers, nothing is known about their interactions in in vivo tumour samples. Here, we report that, in 162 breast carcinomas, p53 mutations are significantly associated with an increased expression of survivin and, in particular, its antiapoptotic splice variants (survivin-DeltaEx3 and survivin-3B). The upregulation of these variant expressions is particularly related to p53 mutations occurring in the residues belonging to the tetramerization domain. The loss of heterozygosity in the p53 gene is also associated with an increased expression of the survivin-DeltaEx3 variant. The expression of the proapoptotic variants (survivin-2B and survivin-2alpha) is not affected by any of these alterations. Our results provide for the first time in vivo evidence that, in human breast cancer, the survivin expression as well as its splicing depends on the p53 status. The results also suggest that the upregulation of antiapoptotic survivin variant expression by the mutant p53 may increase breast cancer cells survival and resistance to therapy.
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PMID:Association of p53 gene alterations with the expression of antiapoptotic survivin splice variants in breast cancer. 1684 56

Tissue factor (TF) is a transmembrane glycoprotein that initiates blood coagulation when complexed with factor VIIa (FVIIa). TF is constitutively expressed in a variety of tumor cells and has been shown to play a role in cellular signaling and tumor progression. In this study, we investigated the effect of TF-FVIIa mediated signaling on apoptosis in human breast cancer cells. Apoptosis was induced by prolonged serum starvation and studied using the Adr-MCF-7 cell line, which has high endogenous TF expression. Treatment of the cells with the combination of FVIIa (10 nM) and FX (150 nM), reduced apoptosis by nearly 50% compared with untreated, control cells using an ELISA that detects histone-DNA fragments. In contrast, FVIIa (10 nM) alone did not significantly prevent apoptosis. Pretreatment of the Adr-MCF-7 cells with hirudin, a specific thrombin inhibitor, did not inhibit the anti-apoptotic effect of the combination of FVIIa and FX, whereas this effect could be abrogated by inhibition of phosphorylation of either p44/42 mitogen-activated protein kinase (MAPK) or protein kinase B (PKB/Akt). In addition, treatment of the Adr-MCF-7 cells with the combination of FVIIa and FX led to a 30-50% increase in the level of the anti-apoptotic protein, survivin, compared with untreated cells using Western blot analysis. These results indicate that formation of TF-FVIIa-FXa complex prevents apoptosis in breast cancer cells by a thrombin-independent pathway. Moreover, the anti-apoptotic effect of this signaling pathway involves phosphorylation of both p44/42 MAPK and PKB/Akt and might be mediated in part by an increase in cell survivin levels.
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PMID:Formation of tissue factor-factor VIIa-factor Xa complex prevents apoptosis in human breast cancer cells. 1689 64

Previous studies using immunohistochemistry suggest that loss of the expression of the prostate-derived Ets transcription factor (PDEF) is a strong indicator for cancer cell malignancy. However, the underlying mechanism for this has not been well elucidated. We determined the role of PDEF in breast cancer cell growth and tumor formation using a series of experiments including Western blotting, promoter-luciferase reporter assay, RNA interference technology and a mouse xenograft model. We also determined the relationship between PDEF expression in human breast tumor specimen and cancer patient survivability. These studies revealed that PDEF expression is inversely associated with survivin expression and breast cancer cell xenograft tumor formation. PDEF-specific shRNA-mediated silencing of PDEF expression resulted in the upregulation of survivin expression in MCF-7 cells, which was associated with increased cell growth and resistance to drug-induced DNA fragmentation (apoptosis). In contrast, survivin-specific siRNA-mediated silencing of survivin expression decreased MCF-7 cell growth. Ectopic expression of PDEF inhibited both survivin promoter activity and endogenous survivin expression. Importantly, shRNA-mediated silencing of PDEF expression in MCF-7 breast cancer cells enhanced survivin expression and xenograft tumor formation in vivo. Furthermore, loss of PDEF expression in breast cancer tissues tends to be associated with unfavorable prognosis. These studies provide new information for the role of PDEF and survivin in breast cancer cell growth and tumor formation.
Breast Cancer Res Treat 2007 Mar
PMID:Prostate-derived Ets transcription factor (PDEF) downregulates survivin expression and inhibits breast cancer cell growth in vitro and xenograft tumor formation in vivo. 1689 29

In order to investigate the effects of short hairpin RNA (shRNA) on the expression of Survivin, cell cycle and cell proliferation in MCF-7 cells, using a pEGFP vector which contained a U6 promoter shRNA plasmid targeted against survivin was constructed and transfected into MCF-7 cells. The change of the expression of Survivin and cell proliferation rates were detected by semiquantitative reverse transcription polymerase chain reaction (RT-PCR) and MTT methods respectively. The change of cell cycle after transfection was analyzed by flow cytometry. The results indicated that the recombinant plasmid containing Survivin shRNA was constructed successfully, which could suppress the expression of Survivin at mRNA and protein level. The growth of MCF-7 cells was arrested in G1 phase of the cell cycle and the proliferation activity was suppressed after transfection. It was concluded that Survivin shRNA plasmid could knock down the expression of Survivin in MCF-7 cells specifically. In addition, Survivin shRNA plasmid could lead to G1 arrest and inhibit the proliferation of MCF-7 cells, which suggested that Survivin shRNA might be used as a new therapeutic method for breast cancer.
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PMID:Effects of Survivin expression suppressed by short hairpin RNA on MCF-7 cells. 1696 Dec 76

Increased expression of casein kinase 2 (CK2) is associated with hyperproliferation and suppression of apoptosis in cancer. Mutations in the tumor suppressor APC (adenomatous polyposis coli) are frequent in colon cancer and often augment beta-catenin-T cell factor (Tcf)/lymphoid enhancer binding factor (Lef)-dependent transcription of genes such as c-myc and cyclin-D1. CK2 has also been implicated recently in the regulation of beta-catenin stability. To identify mechanisms by which CK2 promotes survival, effects of the specific CK2 inhibitors 4,5,6,7-tetrabromobenzotriazole (TBB) and 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole were assessed. TBB and 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole significantly decreased proliferation and increased apoptosis of HT29(US) colon cancer cells. RT-PCR and immunoblot analysis revealed that both inhibitors decreased survivin mRNA and protein levels in HT29(US) cells. Similar effects were observed with TBB in human DLD-1 and SW-480 colorectal cells as well as ZR-75 breast cancer cells and HEK-293T embryonic kidney cells. Expression of GFP-CK2alpha in HEK-293T cells resulted in beta-catenin-Tcf/Lef-dependent up-regulation of survivin and increased resistance to anticancer drugs. Augmented beta-catenin-Tcf/Lef-dependent transcription and resistance to apoptosis observed upon GFP-CK2alpha expression were abolished by TBB. Alternatively, HEK-293T cells expressing GFP-survivin were resistant to TBB-induced apoptosis. Finally, siRNA-mediated down-regulation of CK2alpha in HEK-293T cells coincided with reduced beta-catenin and survivin levels. Taken together, these results suggest that CK2 kinase activity promotes survival by increasing survivin expression via beta-catenin-Tcf/Lef-mediated transcription. Hence, selective CK2 inhibition or down-regulation in tumors may provide an attractive opportunity for the development of novel cancer therapies.
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PMID:Casein kinase 2 (CK2) increases survivin expression via enhanced beta-catenin-T cell factor/lymphoid enhancer binding factor-dependent transcription. 1700 22

This study was conducted to investigate the serum and urine levels of survivin in patients with breast cancer and the relationships with known prognostic parameters and therapy. Forty-three patients with breast cancer and 21 healthy control subjects were investigated. Serum samples were obtained on the first admission before adjuvant and metastatic treatment were given and after two cycles of chemotherapy. Serum and urine survivin levels were determined using enzyme immunometric assay (EIA) and enzyme-linked immunosorbent assay (ELISA), respectively. There was no significant difference in the baseline serum and urine levels between patients with breast carcinoma and healthy controls (p = 0.19 and p = 0.84, respectively). None of the prognostic parameters analyzed were significantly correlated with the urine survivin concentrations. This was also true for serum survivin values, except for nodal involvement. Serum survivin levels were significantly higher in the patients with nodal involvement compared with node negatives (p = 0.043). However, serum survivin levels were not influenced by the number of involved nodes (p = 0.77). No significant correlation was found between the serum and urine levels of survivin (r = 0.15, p = 0.27). Serum and urine levels did not change significantly after chemotherapy (p = 0.59 and p = 0.50, respectively). In conclusion, the result of this study suggested that serum survivin level could be a sensitive marker for detecting metastases in lymph nodes from breast cancer patients. However, much research continues in this field, and exciting new knowledge will ultimately emerge.
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PMID:Serum and urine survivin levels in breast cancer. 1701 90

The cyclopentenone prostaglandin 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) exerts a growth inhibitory effect on cancer cells, and this effect is linked to the induction of apoptosis or cell cycle arrest. Induction of apoptosis by 15d-PGJ(2) is associated with the down-regulation of anti-apoptotic proteins. G(0)-G(1)-->S phase progression is inhibited by 15d-PGJ(2) via the degradation of cyclin D1. In this study, we further investigated the mechanism by which 15d-PGJ(2) inhibits cancer cell growth by using the breast cancer cell lines MCF-7 and T-47D. Treatment with 20 microM 15d-PGJ(2) for 72 h completely blocked the growth in both cell lines. However, the proportions of apoptotic MCF-7 and T-47D cells were 21.1% and 40.9%, respectively, indicating that the induction of apoptosis did not appear to fully account for growth inhibition by 15d-PGJ(2). Cell cycle analysis using cells synchronized at the G(0)-G(1) or S phase revealed that 15d-PGJ(2) blocked not only G(0)-G(1)-->S phase progression but also G(2)-M phase progression. The expression of both cyclins D1 and B1 was decreased by 15d-PGJ(2). Furthermore, 15d-PGJ(2) inhibited aurora-B kinase activity, which coincided with the down-regulation of survivin. Thus, 15d-PGJ(2) induced cell cycle arrest at the G(2)-M phase via inhibition of cyclin B1 expression and aurora-B kinase activity. We conclude that survivin may be an important target for 15d-PGJ(2), and its down-regulation may lead to a decrease in aurora-B kinase activity.
Breast Cancer Res Treat 2007 May
PMID:15-deoxy-Delta(12,14)-prostaglandin J2 inhibits G2-M phase progression in human breast cancer cells via the down-regulation of cyclin B1 and survivin expression. 1702 81

The identification of differentially regulated apoptotic signals in normal and tumor cells allows the development of cancer cell-selective therapies. Increasing evidence shows that the inhibitor of apoptosis (IAP) proteins survivin and XIAP are highly expressed in tumor cells but are absent or have very low levels of expression in normal adult tissues. We found that inhibiting AKT activity with 10 to 100 nM deguelin, a small molecule derived from natural products, markedly reduced the levels of both survivin and XIAP, inducing apoptosis in human breast cancer cells but not in normal cells. It is noteworthy that we detected an elevated level of cleaved poly(ADP-ribose) polymerase, a signature of caspase activation, without a significant increase in caspase activity in deguelin-treated cancer cells. Our results suggest that severe down-regulation of the IAPs by deguelin releases their inhibitory activity over pre-existing active caspases present in cancer cells, inducing apoptosis without the need for further caspase activation. Because normal cells have very low levels of p-AKT, XIAP, survivin, and pre-existing caspase activity, deguelin had little effect on those cells. In addition, we found that combining deguelin with chemotherapy drugs enhanced drug-induced apoptosis selectively in human tumor cells, which suggests that deguelin has great potential for chemosensitization and could represent a new therapeutic agent for treatment of breast cancer.
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PMID:Down-regulation of inhibitor of apoptosis proteins by deguelin selectively induces apoptosis in breast cancer cells. 1703 97

Our aim was to study the effects of cucurbitacin glucosides extracted from Citrullus colocynthis leaves on human breast cancer cell growth. Leaves were extracted, resulting in the identification of cucurbitacin B/E glucosides. The cucurbitacin glucoside combination (1:1) inhibited growth of ER(+) MCF-7 and ER(-) MDA-MB-231 human breast cancer cell lines. Cell-cycle analysis showed that treatment with isolated cucurbitacin glucoside combination resulted in accumulation of cells at the G(2)/M phase of the cell cycle. Treated cells showed rapid reduction in the level of the key protein complex necessary to the regulation of G(2) exit and initiation of mitosis, namely the p34(CDC2)/cyclin B1 complex. cucurbitacin glucoside treatment also caused changes in the overall cell morphology from an elongated form to a round-shaped cell, which indicates that cucurbitacin treatment caused impairment of actin filament organization. This profound morphological change might also influence intracellular signaling by molecules such as PKB, resulting in inhibition in the transmission of survival signals. Reduction in PKB phosphorylation and inhibition of survivin, an anti-apoptosis family member, was observed. The treatment caused elevation in p-STAT3 and in p21(WAF), proven to be a STAT3 positive target in absence of survival signals. Cucurbitacin glucoside treatment also induced apoptosis, as measured by Annexin V/propidium iodide staining and by changes in mitochondrial membrane potential (DeltaPsi) using a fluorescent dye, JC-1. We suggest that cucurbitacin glucosides exhibit pleiotropic effects on cells, causing both cell cycle arrest and apoptosis. These results suggest that cucurbitacin glucosides might have therapeutic value against breast cancer cells.
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PMID:Growth inhibitory activity of cucurbitacin glucosides isolated from Citrullus colocynthis on human breast cancer cells. 1704 94

Survivin has emerged as a unique regulator of cell death through its response to growth factors, such as basic fibroblast growth factor (bFGF), which we have previously shown to be mitogen-activated protein kinase (MAPK) dependent. The transcriptional complex myc/max is an oncogene that lies downstream of the MAPK pathway, suggesting a possible role in survivin's regulation. In this study, we investigated the ability of bFGF to induce signalling of the MAPK effector transcription factor c-myc in human breast cancer. Treatment of SK-BR-3 breast cancer cell line with growth factor induced survivin expression and recruitment of c-myc to its response element in the promoter region of the target gene survivin as demonstrated by electromobility shift analysis and chromatin immunoprecipitation assays. The promoter region of survivin was assessed using bioinformatic techniques and DNA footprinting. Overexpression of c-myc increased survivin protein expression. This effect was eliminated when siRNA against c-myc was transfected into the cells. c-Myc drove transcriptional activity of survivin when transfected into SK-BR-3 cells with a luciferase reporter vector harbouring the c-myc response element specific for survivin. Using confocal fluorescent microscopy, myc was located to the nucleus of breast tumour epithelial cells and was found to be significantly associated with survivin (P < 0.0001). These data provide evidence that growth factors can signal through the transcription factor c-myc in human breast cancer. They also indicate a role for c-myc in the transcriptional regulation of survivin in breast cancer.
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PMID:Growth factor-dependent regulation of survivin by c-myc in human breast cancer. 1717 79


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