Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0006142 (breast cancer)
 160,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transforming growth factor-beta 1 (TGF-beta1) signaling in tumor cells has been implicated in tumor angiogenesis and metastasis by regulating matrix proteolysis. Although MMP-9/gelatinase-B is an important component of these TGF-beta1 responses, the mechanism of its regulation is not well understood. Here, we present evidence that TGF-beta-activated protein kinase 1 (TAK1) is critical for TGF-beta regulation of MMP-9 and the metastatic potential of breast cancer cell line MDA-MB-231. We found that suppression of TAK1 signaling by dominant-negative (dn) TAK1 or RNA interference (siRNA) reduces expression of MMP-9 and tumor cell invasion, without growth inhibition in cell culture. The orthotopic xenograft studies in SCID mice showed that suppression of TAK1 signaling by dn-TAK1 reduces tumor growth and formation of lung metastases. Dn-TAK1 reduced the proliferation Ki-67 index and neovasculature of orthotopic xenografts. TAK1-mediated regulation of MMP-9 involves NF-kappaB signaling. Dn-TAK1 reduces NF-kappaB transcriptional response and inhibition of NF-kappaB reduces expression of MMP-9 and activity of the MMP-9 promoter reporter. Together, these findings suggest that TAK1 contributes to TGF-beta1-mediated tumor angiogenesis and metastasis via a mechanism involving the TAK1-NF-kappaB-MMP-9 pathway.
 ...
PMID:TAK1 is required for TGF-beta 1-mediated regulation of matrix metalloproteinase-9 and metastasis. 1782 8

Since most breast cancers occur in postmenopausal women and are hormone dependent, we developed a model system that mimics this situation. In this model, tumors of human estrogen receptor (ER) positive breast cancer cells stably transfected with aromatase (Ac-1) are grown in immune-compromised mice. Using this model we have explored a number of therapeutic strategies to maximize the antitumor efficacy of antiestrogens (AEs) and aromatase inhibitors (AIs). This intratumoral aromatase xenograft model has proved accurate in predicting the outcome of several clinical trials. In this current study we compared the effect of an AE toremifene and steroidal AI atamestane, alone or in combination, on growth of hormone-dependent human breast cancer. We have also compared toremifene plus atamestane combination with tamoxifen in this study. The growth of Ac-1 cells was inhibited by tamoxifen, toremifene and atamestane in vitro with IC(50) values of 1.8+/-1.3 microM, 1+/-0.3 microM and 60.4+/-17.2 microM, respectively. The combination of toremifene plus atamestane was found to be better than toremifene or atamestane alone in vitro. The effect of this combination was then studied in vivo using Ac-1 xenografts grown in ovariectomized female SCID mice. The mice were injected with toremifene (1000 microg/day), atamestane (1000 microg/day), tamoxifen (100 microg/day), or the combination of toremifene plus atamestane. In this study, our results indicate that the combination of toremifene plus atamestane was as effective as toremifene or tamoxifen alone but may not provide any additional benefit over toremifene alone or tamoxifen alone.
 ...
PMID:Toremifene-atamestane; alone or in combination: predictions from the preclinical intratumoral aromatase model. 1794 1

A series of polyaromatic guanidino derivatives was synthesized and evaluated for growth inhibitory properties in several human carcinoma cell lines. The properties of these guanidino compounds were compared to those of their corresponding synthetic amino precursors. The size of the polyaromatic ring system as well as the length of the tether attached to the ring had a direct impact on the observed antiproliferative profiles, compound 14 having the broadest spectrum of activity. As both series intercalate DNA, guanidine derivatives showed a remarkable affinity for DNA and the guanidinium group appeared to be essential, yet not sufficient for caspase-3/7 activation. Compound 14 also showed significant in vivo activity against breast cancer cell xenografts in NOG/SCID mice. These results suggest that the electronic nature of chain tethering an intercalator not only influences the DNA-binding process but also controls the antitumoral activity of the whole compound.
 ...
PMID:Amine-guanidine switch: a promising approach to improve DNA binding and antiproliferative activities. 1805 16

Cancers may arise from rare self-renewing tumor-initiating cells (T-IC). However, how T-IC self renewal, multipotent differentiation, and tumorigenicity are maintained remains obscure. Because miRNAs can regulate cell-fate decisions, we compared miRNA expression in self-renewing and differentiated cells from breast cancer lines and in breast T-IC (BT-IC) and non-BT-IC from 1 degrees breast cancers. let-7 miRNAs were markedly reduced in BT-IC and increased with differentiation. Infecting BT-IC with let-7-lentivirus reduced proliferation, mammosphere formation, and the proportion of undifferentiated cells in vitro and tumor formation and metastasis in NOD/SCID mice, while antagonizing let-7 by antisense oligonucleotides enhanced in vitro self renewal of non-T-IC. Increased let-7 paralleled reduced H-RAS and HMGA2, known let-7 targets. Silencing H-RAS in a BT-IC-enriched cell line reduced self renewal but had no effect on differentiation, while silencing HMGA2 enhanced differentiation but did not affect self renewal. Therefore let-7 regulates multiple BT-IC stem cell-like properties by silencing more than one target.
 ...
PMID:let-7 regulates self renewal and tumorigenicity of breast cancer cells. 1808 1

We have recently shown that despite of the fact that the ErbB2-positive JIMT-1 human breast cancer cells intrinsically resistant to trastuzumab in vitro, trastuzumab inhibited the outgrowth of early phase JIMT-1 xenografts in SCID mice via antibody-dependent cellular cytotoxicity (ADCC). Here we show that trastuzumab significantly reduces the number of circulating and disseminated tumor cells (CTCs and DTCs) in this xenograft model system at a time when the primary tumor is already unresponsive to trastuzumab. This observation suggests that ErbB2 positive CTCs and DTCs might be sensitive to trastuzumab-mediated ADCC even if when the primary tumor is already non-responsive. Thus, trastuzumab treatment might also be beneficial in the case of patients with breast cancer that is already trastuzumab resistant.
 ...
PMID:Trastuzumab decreases the number of circulating and disseminated tumor cells despite trastuzumab resistance of the primary tumor. 1809 13

Breast cancer is the most commonly diagnosed malignancy in women worldwide. Metastatic development is associated with poor prognosis and current therapies provide only limited success. Virotherapy is an emerging strategy for the treatment of cancer that utilizes both replication-competent and genetically modified viruses to selectively kill tumor cells. We have previously shown that Coxsackievirus A21 (CVA21), a wild-type common-cold producing enterovirus, is an effective oncolytic agent against human melanoma xenografts in vivo. CVA21 specifically targets and lytically infects susceptible cells expressing the CVA21 cellular receptors, intercellular adhesion molecule-1 (ICAM-1) and/or decay-accelerating factor (DAF). Herein, the efficacy of CVA21 as a therapeutic agent against human breast cancer was investigated both in vitro and in vivo. Flow cytometric analysis revealed that the human breast cancer cell lines examined expressed significantly elevated levels of surface ICAM-1 and DAF compared to normal breast cell lines, and that all cancerous lines were more susceptible to lytic infection by CVA21 than the normal cells. Through the use of subcutaneous (T47D cells) and orthotopic (MDA-MB-231-luc cells) xenograft SCID mouse models it was demonstrated that a single intravenous injection of CVA21 produced significant regression of pre-established tumors in vivo, as well as targeting and elimination of metastases in the orthotopic model. Taken together, these findings highlight the exciting potential of CVA21 as a therapeutic agent against both primary and metastatic human breast cancer.
Breast Cancer Res Treat 2009 Jan
PMID:Systemic targeting of metastatic human breast tumor xenografts by Coxsackievirus A21. 1825 29

Human breast cancer frequently metastasizes to bone, and effective therapies for patients with bone metastasis are required. However, the molecular mechanism for the bone metastasis of human breast cancer has not yet been fully elucidated. The present study aimed to evaluate the importance of active osteoclasts and bone-derived insulin-like growth factors (IGFs) for the survival and growth of breast cancer cells in bone. Human breast cancer cell line MCF-7 cells were injected into human adult bone (HAB) implanted into nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. The mice were then treated with recombinant human osteoclastogenesis inhibitory factor/osteoprotegerin (rhOCIF/OPG), a decoy receptor for receptor activator of NF-kappaB ligand (RANKL), or an anti-human IGF monoclonal antibody. Histomorphometric analyses revealed that both treatments significantly decreased the tumor area of MCF-7 cells in cross-sections of the implanted HAB to about 30% of the tumor area in control mice, but had no effect on the growth of subcutaneously injected MCF-7 cells. Consistent with the results for the tumor area in HAB, there were fewer osteoclasts in the implanted HAB in rhOCIF/OPG-treated mice than in vehicle-treated mice. However, treatment with the anti-human IGF monoclonal antibody had no effect on the number of osteoclasts in HAB. The results indicate that the active osteoclasts induced by RANKL and the IGFs released as a result of bone resorption by these osteoclasts play crucial roles in the survival and growth of human breast cancer cells in bone and suggest that neutralization of bone-derived IGFs will be effective in preventing the development of bone tumors in breast cancer patients.
 ...
PMID:Roles of osteoclasts and bone-derived IGFs in the survival and growth of human breast cancer cells in human adult bone implanted into nonobese diabetic/severe combined immunodeficient mice. 1830 47

S100A7 is a small calcium binding protein, which has been shown to be differentially expressed in psoriatic skin lesions, as well as in squamous cell tumors of the skin, lung and breast. Although its expression has been correlated to HER+ high-grade tumors and to a high risk of progression, the molecular mechanisms of these S100A7-mediated tumorigenic effects are not well known. Here, we showed for the first time that epidermal growth factor (EGF) induces S100A7 expression in both MCF-7 and MDA-MB-468 cell lines. We also observed a decrease in EGF-directed migration in shRNA-downregulated MDA-MB-468 cell lines. Furthermore, our signaling studies revealed that EGF induced simultaneous EGF receptor phosphorylation at Tyr1173 and HER2 phosphorylation at Tyr1248 in S100A7-downregulated cell lines as compared to the vector-transfected controls. In addition, reduced phosphorylation of Src at tyrosine 416 and p-SHP2 at tyrosine 542 was observed in these downregulated cell lines. Further studies revealed that S100A7-downregulated cells had reduced angiogenesis in vivo based on matrigel plug assays. Our results also showed decreased tumor-induced osteoclastic resorption in an intra-tibial bone injection model involving SCID mice. S100A7-downregulated cells had decreased osteoclast number and size as compared to the vector controls, and this decrease was associated with variations in IL-8 expression in in vitro cell cultures. This is a novel report on the role of S100A7 in EGF-induced signaling in breast cancer cells and in osteoclast formation.
 ...
PMID:S100A7-downregulation inhibits epidermal growth factor-induced signaling in breast cancer cells and blocks osteoclast formation. 1832 59

Breast tumour stem cells have been reported to differentiate in the epithelial lineage but a cross-lineage potential has not been investigated. We aimed to evaluate whether breast tumour stem cells were able to differentiate also into the endothelial lineage. We isolated and cloned a population of breast tumour stem cells, cultured as mammospheres that expressed the stem markers nestin and Oct-4 and not epithelial and endothelial differentiation markers, and formed serially transplantable tumours in SCID mice. When cultured in the presence of serum, mammosphere-derived clones differentiated in the epithelial lineage. When cultured in the presence of VEGF, the same clones were also able to differentiate in the endothelial lineage acquiring endothelial markers and properties, such as the ability to organize in Matrigel into capillary-like structures. In the transplanted tumours, originated from mammospheres, we demonstrate that some of the intratumour vessels were of human origin, suggesting an in vivo endothelial differentiation of mammosphere-derived cells. Finally, endothelial cell clones originated from mammospheres were able, when implanted in Matrigel in SCID mice, to form after 7 days a human vessel network and, after 3-4 weeks, an epithelial tumour suggesting that in the endothelial-differentiated cells a tumourigenic stem cell population is maintained. In conclusion, the results of the present study demonstrate that stem cells of breast cancer have the ability to differentiate not only in epithelial but also in endothelial lineage, further supporting the hypothesis that the tumour-initiating population possesses stem cell characteristics relevant for tumour growth and vascularization.
 ...
PMID:Endothelial cell differentiation of human breast tumour stem/progenitor cells. 1841 May 28

The cancer stem cell hypothesis proposes that cancers arise in stem/progenitor cells through disregulation of self-renewal pathways generating tumors, which are driven by a component of 'tumor-initiating cells' retaining stem cell properties. The HER2 gene is amplified in 20-30% of human breast cancers and has been implicated in mammary tumorigenesis as well as in mediating aggressive tumor growth and metastasis. We demonstrate that HER2 overexpression drives mammary carcinogenesis, tumor growth and invasion through its effects on normal and malignant mammary stem cells. HER2 overexpression in normal mammary epithelial cells (NMEC) increases the proportion of stem/progenitor cells as demonstrated by in vitro mammosphere assays and the expression of stem cell marker aldehyde dehydrogenase (ALDH) as well as by generation of hyperplastic lesions in humanized fat pads of NOD (nucleotide-binding oligomerization domain)/SCID (severe combined immunodeficient) mice. Overexpression of HER2 in a series of breast carcinoma cell lines increases the ALDH-expressing 'cancer stem cell' population which displays increased expression of stem cell regulatory genes, increased invasion in vitro and increased tumorigenesis in NOD/SCID mice. The effects of HER2 overexpression on breast cancer stem cells are blocked by trastuzumab in sensitive, but not resistant, cell lines, an effect mediated by the PI3-kinase/Akt pathway. These studies provide support for the cancer stem cell hypothesis by suggesting that the effects of HER2 amplification on carcinogenesis, tumorigenesis and invasion may be due to its effects on normal and malignant mammary stem/progenitor cells. Furthermore, the clinical efficacy of trastuzumab may relate to its ability to target the cancer stem cell population in HER2-amplified tumors.
 ...
PMID:HER2 regulates the mammary stem/progenitor cell population driving tumorigenesis and invasion. 1859 32


<< Previous 1 2 3 4 5 6 7 8 9 10