Notch1 is involved in migration and invasion of human breast cancer cells

The Notch pathway displays several functions related to tumor progression. Breast carcinomas commonly express Notch1, Notch2, Notch3 and Notch4 at variable levels and these are mainly involved in differentiation, proliferation and survival. Notch1 can also induce the invasion of breast cancer cells. However, the precise role and mechanism of Notch1 in tumor invasion remains unclear. In?this report, we used small interference RNA technology to knock down the expression of Notch1, resulting in reduced migration and invasion of breast cancer cells. Meanwhile, F-actin polymerization, which is essential for cellular generation of the forces needed for motility, was also impaired in Notch1 knockdown cells. We further investigated the expression of extracellular matrix metalloproteinase inducer (EMMPRIN), matrix metalloproteases-2 (MMP-2) and MMP-9, and found that the expression of functional EMMPRIN and MMP-2 was significantly decreased in Notch1 knockdown cells, while the expression of MMP-9 was constant. Additionally, the silencing of?Notch1 expression likewise impaired cell-to-matrix and cell-to-cell adhesion. Western blotting results showed that reduction of Notch1 levels impacted the phosphorylation of PAK, phosphorylation of Akt, phosphorylation of FAK, the phosphorylation of integrin β1, ICAM-1 and β-catenin. Collectively, these findings suggest that targeting Notch1 has important therapeutic value in breast cancer.     

Total visual blindness is protective against breast cancer

Objective  

Observational data, though sparse and based on small studies with limited ability to control for known breast cancer risk factors, support a lower risk of breast cancer in blind women compared to sighted women. Mechanisms influenced by ocular light perception, such as melatonin or circadian synchronization, are thought to account for this lower risk.     

Notch基因在人乳腺癌中的作用

目的检测Notch1和JAG1在乳腺癌中的表达,及其与乳腺癌相关临床指标的关系,分析Notch基因在人类乳腺癌中的作用和意义。方法应用逆转录聚合酶链反应（RT—PCR）检测60例乳腺癌组织和25例癌旁正常乳腺组织Notch1和JAG1的表达,对乳腺癌组织与癌旁组织进行表达率和表达强度标准化系数的统计学比较,并在不同的腋窝淋巴结转移情况间、不同TNM分期和病理学分级间进行Notch1表达强度标准化系数的统计学比较。结果乳腺癌组织Notch1的表达率和标准化系数分别为93．3％（56／60）和0．83,均明显高于癌旁组织,乳腺癌组织中JAG1的表达率为10％（6／60）,癌旁组织中无JAG1表达,伴腋窝淋巴结转移的病例Notch1标准化系数高于无腋窝淋巴结转移的病例;乳腺癌Ⅰ期病例Notch1标准化系数（0．57）低于Ⅱ期（1．05）Ⅱ期高于Ⅲ期（0．59）,Ⅰ期与Ⅲ期差异无统计学意义;乳腺癌Ⅰ级病例Notch1标准化系数（0．55）低于Ⅱ级（0．83）和Ⅱ级低于Ⅲ级（1．05）,Notch1可能在分化较好的人乳腺癌中的表达是低的,在分化较差的人乳腺癌中的表达是增高的。结论人类乳腺癌中存在Notch1和JAG1的异常高表达,提示Notch1的异常表达与活化可能与人类乳腺癌的形成有关,在人类乳腺癌不同发展阶段的作用可能不同。     

Notch信号在人类乳腺癌中的作用

目的观察Notch1和JAG1在乳腺癌中的表达及其与乳腺癌相关因素的关系,探讨Notch信号在人类乳腺癌中的作用。方法应用逆转录聚合酶链反应(RT-PCR)检测62例乳腺癌组织及22例癌旁正常乳腺组织中Notch1和JAG1的表达,对乳腺癌组织与癌旁正常乳腺组织进行表达率和表达强度标准化系数的统计学比较,并在不同的腋窝淋巴结转移情况间、不同的临床分期间进行Notch1表达强度标准化系数的统计学比较。结果乳腺癌组织Notch1的表达率和标准化系数分别为98.0%和0.91,均明显高于癌旁正常乳腺组织,乳腺癌组织中JAG1的表达率为15.0%,癌旁组织中无JAG1表达;伴腋窝淋巴结转移的病例Notch1标准化系数高于无腋窝淋巴结转移的病例;乳腺癌Ⅰ期病例Notch1标准化系数(0.66)低于Ⅱ期(1.20),Ⅱ期高于Ⅲ期(0.62),Ⅰ期与Ⅲ期差异无统计学意义。结论人类乳腺癌中存在Notch1和JAG1的异常高表达,提示Notch1的异常表达与活化人能与人类乳腺癌的形成有关,Notch1在人类乳腺癌不同发展阶段的作用可能不同。     

Notch activation stimulates migration of breast cancer cells and promotes tumor growth

Introduction

Dysregulated NOTCH receptor activity has been implicated in breast cancer but the mechanisms by which NOTCH contributes to transformation are not yet clear, as it has context-dependent effects on the properties of transformed cells.

Methods

We have used various in vitro and in vivo carcinogenic models to analyze the impact of Notch signaling in the onset and progression of breast tumors.

Results

We found that ectopic expression of the Notch1 intracellular domain (N1ICD) in MCF-7 breast adenocarcinoma cell line caused reduction and delocalization of E-CADHERIN levels and increased migratory and invasive abilities. Notch inhibition in the invasive breast cancer cell line MDA-MB-231 resulted in increased E-CADHERIN expression and a parallel reduction in their invasive capacity. The growth of subcutaneous xenografts produced with MCF-7 cells was boosted after N1ICD induction, in a cell autonomous manner. In vivo Notch1 activation in the mammary gland using the MMTV-Cre driver caused the formation of papillary tumors that showed increased Hes1 and Hey1 expression and delocalized E-cadherin staining.

Conclusions

These results confirm NOTCH1 as a signal triggering epithelial-mesenchymal transition in epithelial cancer cells, which may have implications in tumor dissemination, metastasis and proliferation in vivo. The identification of specific factors interacting with NOTCH signaling could thus be relevant to fully understanding the role of NOTCH in breast neoplasia.     

Curcumin enhances the anticancer effects of trichostatin a in breast cancer cells

Breast cancer patients with HER‐2 positive or estrogen receptor negative tumors have a poor prognosis because these tumors are aggressive and respond poorly to standard therapies. Histone deacetylase (HDAC) inhibitors have been shown to decreased cell survival, which suggests that HDAC inhibitors may be developed for preventing and treating breast cancer. Curcumin has anti‐inflammatory and proapoptotic effects in cancer cells. We determined whether the HDAC inhibitor, Tricostatin A (TSA) in combination with curcumin would produce greater antiproliferative and apoptotic effects than either agent alone. Increasing the concentration of curcumin from 10 to 20 µM enhanced the growth inhibitory effects of the combination in SkBr3 and 435eB breast cancer cells, which was accompanied by decreased viability along with decreased phosphorylation of ERK and Akt. The decreased cell viability observed in SkBr3 cells when curcumin was combined with TSA led to a G0/G1 cell cycle arrest and increased p21 and p27, and decreased Cyclin D1 protein expression. The combination induced cleavage of caspase 3 and poly(ADP‐ribose) polymerase‐1, suggesting that cell death occurred by apoptosis. There were no changes in protein expression of Bcl2, Bax, or Bcl‐xL and decreased expression of p53. The combination increased protein expression of phosphorylated JNK and phosphorylated p38. Pharmacological inhibition of JNK, but not p38, attenuated the decreased viability induced by the curcumin and TSA combination. We conclude that p53 independent apoptosis induced by combining curcumin and TSA involves JNK activation. These findings provide a rationale for exploring the potential benefits of the combination of curcumin with TSA for treatment of breast cancer. © 2012 Wiley Periodicals, Inc.     

Collagen induced MMP-2 activation in human breast cancer

Summary Matrix metalloproteinase-2 (MMP-2), a zymogen requiring proteolytic activation for catalytic activity, has been implicated broadly in the invasion and metastasis of many cancer model systems, including human breast cancer (HBC). MMP-2 has been immunolocalized to carcinomatous human breast, where the degree of activation of MMP-2 correlates well with tumor grade and patient prognosis. Using Matrigel assays, we have stratified HBC cell lines for invasivenessin vitro, and compared this to their potential for metastatic spread in nude mice. HBC cell lines expressing the mesenchymal marker protein vimentin were found to be highly invasivein vitro, and tended to form metastases in nude mice. We have further discovered that culture on collagen-I gels (Vitrogen^TM; Vg) induces MMP-2-activator in highly invasive but not poorly invasive HBC cell lines. As seen for other MMP-2-activator inducing regimens, this induction requires protein synthesis and an intact MMP-2 hemopexin-like domain, appears to be mediated by a cell surface activity, and can be inhibited by metalloproteinase inhibitors. The induction is highly specific to collagen I, and is not seen with thin coatings of collagen I, collagen IV, laminin, or fibronectin, or with 3-dimensional gels of laminin, Matrigel, or gelatin. This review focuses on collagen I and MMP-2, their localization and source in HBC, and their relationship(s) to MMP-2 activation and HBC metastasis. The relevance of collagen I in activation of MMP-2in vivo is discussed in terms of stromal cell: tumor cell interaction for collagen I deposition, MMP-2 production, and MMP-2-activation. Such cooperativity may existin vivo for MMP-2 participation in HBC dissemination. A more complete understanding of the regulation of MMP-2-activator by type I collagen may provide new avenues for improved diagnosis and prognosis of human breast cancer.     

Efficacy of oncolytic reovirus against human breast cancer cells

Human reovirus can replicate and induce tumor cell lysis in several cancer types with an activated Ras signaling pathway. The aim of this study was to investigate the oncolytic effect of reovirus against breast cancer cells, and clarify the relationship between the susceptibility to reovirus and HER2 expression, which is associated with the Ras signaling pathway. Reovirus (serotype 3), 6 human breast cancer cell lines and normal mammary gland epithelial cell line were used in this study. The mRNA expression of HER2 receptor was examined by RT-PCR, and the protein of HER2 and activated Ras protein were examined by a Western blot analysis. In vitro, the cytopathic effects, viral protein synthesis, and cell viability on infection by reovirus were examined. Reovirus can infect all the 6 examined cancer cell lines, but the control cell line was not susceptible to the reovirus infection. The cytopathic effect appeared from day 1 after infection, and a 50% or greater cytotolysis was demonstrated at day 7 after infection. The Ras activities in all examined cell lines were higher than those in the control cell line. No relationship was observed in the susceptibility to the reovirus and HER2 expression. The increased Ras activity itself, regardless of the HER2 expression, may therefore play an important role in the susceptibility to reovirus of breast cancer cells. As a result, breast cancer may thus become a candidate target for oncolytic reovirus therapy.     

Ras activation in human breast cancer

Genetic ras mutations are infrequent in breast cancer but Ras may be pathologically activated in breast cancer by overexpression of growth factor receptors which signal through Ras. Using a highly sensitive, coupled enzymatic assay, we measured Ras activation in 20 breast cancers, two fibroadenomas, and seven normal breast samples. Ras was highly activated compared to benign tissue in 11 of the 20 cancer; 7 of these 11 cancers expressed both the epidermal growth factor (EGF) and ErbB-2/neu/HER-2 receptors with the remaining four cancers with high Ras activation expressing one of these two receptors. In the other nine cancers, Ras activation was similar to that observed in benign breast tissue with none of these cancers expressing the EGF receptor while one expressed the ErbB-2 receptor. None of the cancers tested had an activating K-ras mutation nor did any of the cancers express a truncated EGF receptor or the c-FMS receptor. The activity of mitogen-activated protein (MAP) kinase was high in the cancers, and reflected the degree of Ras activation. In cultured mammary tumor cell lines, we showed that Ras activation was ligand dependent in cells overexpressing the ErbB-2 receptor. Thus, Ras was abnormally activated in breast cancers overexpressing the EGF and/or ErbB-2 receptors indicating there are sufficient ligands in vivo to activate these receptors, and this work provides a basis for new target-based treatments of this disease.     

Thymoquinone anticancer activity is enhanced when combined with royal jelly in human breast cancer

BACKGROUNDBreast cancer is the most common cause of the majority of cancer-related deaths in women, among which triple-negative breast cancer is the most aggressive type of breast cancer diagnosed with limited treatment options. Thymoquinone (TQ), the main bioactive constituent of Nigella sativa, has been extensively studied as a potent anticancer molecule against various types of cancers. Honeybee products such as the royal jelly (RJ), the nutritive secretion fed to honeybee queens, exhibit a variety of biological activities besides its anticancer effect. However, the anticancer activity of the combination of TQ and RJ against breast cancer is still unknown. AIMTo investigate cytotoxicity of RJ in FHs 74 Int cells and the anticancer effects of TQ, RJ, and their combinations in the MDA-MB-231 cell line.METHODSCells were treated with TQ, RJ, and their combinations for 24 h. Using 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, we determined the half-maximal inhibitory concentration of TQ. Trypan blue and 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays were then performed to assess the cell viability in response to different treatment conditions. Cell death and cycle regulation were investigated using propidium iodide deoxyribonucleic acid staining followed by flow cytometry in response to a single dose of TQ, RJ, and their combination. Immunostaining for cleaved caspase 3 and Ki67 expression was used to determine apoptosis induction and changes in cell proliferation. RESULTSTQ alone inhibited cell viability in a dose-dependent manner at concentrations below and above the half-maximal inhibitory concentration. RJ exhibited relatively nontoxic effects against MDA-MB-231 cells and FHs 74 Int small intestinal cells at concentrations below 5 µg/mL. High doses of RJ (200 µg/mL) had greater toxicity against MDA-MB-231 cells. Interestingly, the inhibition of cell viability was most pronounced in response to 15 µmol/L TQ and 5 µg/mL RJ. A dose of 15 µmol/L TQ caused a significant increase in the PreG1 population, while a more pronounced effect on cell viability inhibition and PreG1 increase was observed in response to TQ and RJ combinations. TQ was the main inducer of caspase 3-dependent apoptosis when applied alone and in combination with RJ. In contrast, no significant regulation of Ki67 expression was observed, indicating that the decrease in cell viability was due to apoptosis induction rather than to inhibition of cell proliferation. CONCLUSIONThis study is the first to report enhanced anticancer effects of TQ and RJ combination against MDA-MB-231 breast cancer cells, which could confer an advantage for cancer therapy.     

Cooperation between Wnt and Notch signalling in human breast cancer

The Wnt and Notch signalling pathways play major roles in mammary gland development and tumourigenesis. During development, these pathways have opposing effects. However, in a recent paper Ayyanan and coworkers show that expression of Wnt1 is sufficient to transform primary human mammary epithelial cells, and that this is in part due to activation of the Notch pathway. This indicates that during tumourigenesis the two pathways cooperate. Here we ask why activation of Wnt signalling alone is sufficient to cause transformation; whether there is evidence for inhibitory crosstalk between the pathways during tumourigenesis; and whether cooperation between these pathways occurs in other forms of cancer.     

Glypican-1 is overexpressed in human breast cancer and modulates the mitogenic effects of multiple heparin-binding growth factors in breast cancer cells.

Glypicans are a family of glycosylphosphatidylinositol-anchored cell surface heparan sulfate proteoglycans implicated in the control of cellular growth and differentiation. Here we show that glypican-1 is strongly expressed in human breast cancers, whereas expression of glypican-1 is low in normal breast tissues. In contrast, the expression of glypican-3 and -4 is only slightly increased in breast cancers by comparison with normal breast tissues, and glypican-2 and -5 are below the level of detection by Northern blotting in both normal and cancer samples. Treatment of MDA-MB-231 and MDA-MB-468 breast cancer cells with phosphoinositide-specific phospholipase-C abrogated the mitogenic response to two heparin-binding growth factors, heparin-binding epidermal growth factor-like growth factor and fibroblast growth factor 2. Stable transfection of these cells with a glypican-1 antisense construct markedly decreased glypican-1 protein levels and the mitogenic response to the same heparin-binding growth factors, as well as that to heregulin alpha, heregulin beta, and hepatocyte growth factor. Syndecan-1 was also expressed at high levels in both breast cancer tissues and breast cancer cells when compared with normal breast tissues. There was a good correlation between glypican-1 and syndecan-1 expression in the tumors. However, clones expressing the glypican-1 antisense construct did not exhibit decreased syndecan-1 levels, indicating that loss of responsiveness to heparin-binding growth factors in these clones was not due to altered syndecan-1 expression. Furthermore, 8 of 10 tumors with stage 2 or 3 disease exhibited high levels of glypican-1 by Northern blot analysis. In contrast, low levels of glypican-1 mRNA were evident in 1 of 10 tumors with stage 2 or 3 disease and in 9 of 10 tumors with stage 1 disease. Taken together, these data suggest that glypican-1 may play a pivotal role in the ability of breast cancer cells to exhibit a mitogenic response to multiple heparin-binding growth factors and may contribute to disease progression in this malignancy.