Normal Breast Epithelial Cell Line Research Articles

Epidermal Growth Factor Receptor Kinase Inhibitors Synergize with TCDD to Induce CYP1A1/1A2 in Human Breast Epithelial MCF10A Cells.

CYP1A1 and CYP1A2 are transcriptionally activated in the human normal breast epithelial cell line MCF10A following exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Shifting MCF10A cultures to medium deficient in serum and epidermal growth factor (EGF) caused rapid reductions in the activated (i.e., phosphorylated) forms of extracellular regulated kinases (ERKs) and the epidermal growth factor receptor (EGFR). Shifting to serum/EGF-deficient medium also enhanced TCDD-mediated induction of cytochrome P450 (CYP)1A1 Treatment of cells cultured in complete medium with the EGFR inhibitors gefitinib (Iressa), AG1478, and CI-1033 resulted in concentration-dependent reductions of active EGFR and ERKs, and increased CYP1A1 mRNA content ∼3- to 18-fold above basal level. EGFR inhibitors synergized with TCDD and resulted in transient CYP1A1 and CYP1A2 mRNA accumulations ∼8-fold greater (maximum at 5 hours) than that achieved with only TCDD. AG1478, gefitinib, and TCDD individually induced small increases (∼1.2- to 2.5-fold) in CYP1A1 protein content but did not cause additive or synergistic accumulations of CYP1A1 protein when used in combination. The mitogen-activated protein kinase kinase inhibitor PD184352 inhibited ERK and EGFR activation in a concentration-dependent fashion without causing CYP1A1 mRNA accumulation. However, cotreatment with PD184352 potentiated TCDD-mediated CYP1A1 induction. TCDD-mediated induction of CYP1A1 in MCF7-TET on-EGFR cells, a MCF7 variant in which EGFR expression can be controlled, was not affected by the activity status of EGFR or ERKs. Hence, EGFR signaling mutes both basal and ligand-induced expression of two aryl hydrocarbon receptor-responsive P450s in MCF10A cultures. However, these effects are cell context-dependent. Furthermore, CYP1A1 mRNA and protein abundance are not closely coupled in MCF10A cultures.

Development and characterization of two human triple-negative breast cancer cell lines with highly tumorigenic and metastatic capabilities.

Triple‐negative breast cancer (TNBC) is a group of cancer with high diversity, limited therapies, and poor prognosis. TNBC cell lines and animal models provide effective tools for studies and drug discovery. Here, we report the development of two TNBC cell lines (XtMCF and LmMCF) based on our existing cell model that consists of normal breast epithelial cell line MCF10F, estradiol‐transformed cells trMCF, and Boyden chamber‐selected tumorigenic cells bsMCF. The XtMCF and LmMCF cell line were derived from xenograft and lung metastasis of bsMCF cells, respectively. The bsMCF, XtMCF, and LmMCF cells have undergone epithelial–mesenchymal transition (EMT), exhibiting a mesenchymal‐like feature. In vivo studies showed XtMCF and LmMCF cells were highly tumorigenic and metastatic. The injection of 5 × 104 cells to CB17/SCID mice mammary fat pad produced xenografts in 9/9 mice and tumors reached 10 millimeters in diameter in 5 weeks. The injection of 1 × 106 XtMCF or 8 × 104 LmMCF cells into the mice tail vein was sufficient to form extensive lung metastases in 4 weeks. The two new cell lines exhibited CD44+/CD49f+ and CD44+/EpCAM + cancer stem cell (CSC) characteristics, and the EGF‐like domain of EpCAM was cleaved off. Together with the normal and early transformed counterparts, herein we provide a complete cancer model for the study of initiation, evolution, and identification of new therapeutics for TNBC. The finding that EGF‐like domain of EpCAM was cleaved off in cells which have undergone EMT suggests this cleavage may be involved in the EMT process and the cancer stem cell properties of these cells.

MiR-27a regulates the sensitivity of breast cancer cells to cisplatin treatment via BAK-SMAC/DIABLO-XIAP axis

MicroRNA-27a (miR-27a) has been reported to be an onco-microRNA in multiple cancers promoting tumor growth and metastasis, but the role of miR-27a in regulating the cancer sensitivity to chemotherapy remains unknown. In this study, upregulation of miR-27a was validated by real-time PCR analysis in breast cancer (BC) cell lines and samples of BC patients. A negative correlation between miR-27a and bak was also observed in normal breast epithelial cell line MCF-10A and BC cell lines, suggesting that the bak is the potential target of miR-27a. miR-27a could modulate the growth and metastasis of BC cells. More importantly, we found that knockdown of miR-27a by the specific inhibitors significantly increased the sensitivity of T-47D cells to cisplatin (CDDP) treatment. After further investigation, we indicated that the knockdown of miR-27a promoted the apoptosis via mitochondrial pathway in T-47D cells treated with CDDP, depending on the BAK-second mitochondria-derived activator of caspase/direct IAP binding protein with low pI (SMAC/DIABLO)-X-linked inhibitor of apoptosis (XIAP) axis. Interestingly, we found that the sensitivity of T-47D cells to some other chemotherapeutic agents (5-fluorouracil, doxorubicin, and tumor necrosis factor-related apoptosis-inducing ligand) was also regulated by miR-27a. These findings improve our understanding of the role of miR-27a in breast cancer and might provide a novel strategy for cancer therapy.

Dendrobium candidum inhibits MCF-7 cells proliferation by inducing cell cycle arrest at G2/M phase and regulating key biomarkers.

BackgroundBreast cancer is one of the most frequently occurring cancers in women. In recent years, Dendrobium candidum has played a part in antihyperthyroidism and anticancer drugs. This study aims to examine the antitumor effect of D. candidum on breast cancer.MethodsHuman breast cancer cell line MCF-7 and normal breast epithelial cell line MCF10A were used to observe the effects of D. candidum treatment on human breast cancer. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was employed to examine the cell proliferation of the MCF-7 and MCF10A cells. Western blot analysis and reverse transcription polymerase chain reaction were used to detect the key molecules and biomarkers in breast cancer pathology. Cell cycle was analyzed by using Becton Dickinson FACScan cytofluorometer.ResultsThe results indicated that D. candidum significantly decreased cell viability at different concentrations compared to the control group (P<0.05). D. candidum-treated MCF-7 cells in the G2/M phase was significantly increased compared to the control group (P<0.05). The messenger RNA levels of estrogen receptor alpha, IGFBP2, IGFBP4, and GATA3 were significantly decreased, and the messenger RNA and protein levels of ELF5, p53, p21, p18, CDH1, CDH2, and p12 were significantly increased, compared to the control group (P<0.05). The protein levels of estrogen receptor alpha, PGR, GATA3, and Ki67 were significantly decreased and the protein levels of p53 and ELF5 were significantly increased compared to the control group (P<0.05). The general apoptosis biomarker, Bcl-2, was significantly decreased and the Bax was significantly increased compared to the control group (P<0.05). In contrast to that in MCF-7, D. candidum does not affect cell proliferation at any concentration and any time points in normal breast epithelial cells, MCF10A cells.ConclusionD. candidum could decrease the cell viability of MCF-7 cells by inducing cell cycle arrest at the G2/M phase and regulating the key biomarkers in breast cancer cells.

Abstract 3947: BP1 protein, a transcription factor, is secreted by breast cancer cells

Abstract Background. BP1 is a homeobox gene which is normally expressed during early hematopoiesis. Homeotic proteins regulate the expression of multiple genes involved in development and differentiation. We have previously shown that BP1 mRNA and protein levels are elevated in 80% of women with invasive ductal breast cancer. Furthermore, BP1 protein (pBP1) overexpression is associated with larger and more aggressive breast tumors. In cultured breast cancer cell lines overexpressing pBP1, we observe decreased cell death and increased proliferation. BP1 overexpression has also been found to stimulate known oncogenes including BCL2 and c-MYC. Methods. Levels of pBP1 were detected in cell extracts (CE) and conditioned media (CM) using Western Blot analysis. Depleted media (DM), in which the pBP1 was removed, and recombinant BP1 protein (rpBP1) were used as controls. Cell viability was assessed using MTT assays. Real-time qPCR was used to measure expression of selected oncogenes. Results. Our results show that: (a) pBP1 is secreted from three breast cancer cell lines but not from two normal breast epithelial cell lines. (b) pBP1 exhibits mitogenic activity towards breast cancer cells and normal breast cells, whether cells are grown in media containing 10x conditioned medium (CM) from cells secreting pBP1 or in media containing purified recombinant pBP1 (rpBP1). (c) Growth of breast cancer cells or normal breast epithelial cells in CM or rpBP1 leads to up-regulation of selected oncogenes known to be targets of BP1. These oncogenes include BCL2 and MET. BP1 itself was stimulated, but only in normal breast epithelial cells. The mechanism of secretion is under investigation. Conclusions. Our data suggest that secreted pBP1 can stimulate cell proliferation and gene expression in tumor cells as well as in nearby normal cells. Citation Format: Jinguen Rheey, Anna Yakovleva, Kellie-Ann Yamane, Patricia E. Berg. BP1 protein, a transcription factor, is secreted by breast cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3947. doi:10.1158/1538-7445.AM2015-3947

Isoliensinine induces apoptosis in triple-negative human breast cancer cells through ROS generation and p38 MAPK/JNK activation.

Isoliensinine, liensinine and neferine are major bisbenzylisoquinoline alkaloids in the seed embryo of lotus (Nelumbo nucifera), and exhibit potential anti-cancer activity. Here, we explored the effects of these alkaloids on triple-negative breast cancer cells and found that among the three alkaloids isoliensinine possesses the most potent cytotoxic effect, primarily by inducing apoptosis. Interestingly, isoliensinine showed a much lower cytotoxicity against MCF-10A, a normal human breast epithelial cell line. Further studies showed that isoliensinine could significantly increase the production of reactive oxygen species (ROS) in triple-negative breast cancer cells, but not in MCF-10A cells. The isoliensinine-induced apoptosis could be attenuated by radical oxygen scavenger N-acetyl cysteine, suggesting that the cytotoxic effect of isoliensinine on cancer cells is at least partially achieved by inducing oxidative stress. We found that both p38 MAPK and JNK signaling pathways were activated by isoliensinine treatment and contributed to the induction of apoptosis. Furthermore, inhibitors or specific siRNAs of p38 MAPK and JNK could attenuate apoptosis induced by isoliensinine. However, only the p38 inhibitor or p38-specific siRNA blocked the elevation of ROS in isoliensinine-treated cells. Our findings thus revealed a novel antitumor effect of isoliensinine on breast cancer cells and may have therapeutic implications.

Surface modification of microparticles causes differential uptake responses in normal and tumoral human breast epithelial cells.

The use of micro- and nanodevices as multifunctional systems for biomedical applications has experienced an exponential growth during the past decades. Although a large number of studies have focused on the design and fabrication of new micro- and nanosystems capable of developing multiple functions, a deeper understanding of their interaction with cells is required. In the present study, we evaluated the effect of different microparticle surfaces on their interaction with normal and tumoral human breast epithelial cell lines. For this, AlexaFluor488 IgG functionalized polystyrene microparticles (3 μm) were coated with Polyethyleneimine (PEI) at two different molecular weights, 25 and 750 kDa. The effect of microparticle surface properties on cytotoxicity, cellular uptake and endocytic pathways were assessed for both normal and tumoral cell lines. Results showed a differential response between the two cell lines regarding uptake efficiency and mechanisms of endocytosis, highlighting the potential role of microparticle surface tunning for specific cell targeting.

(6E,10E) Isopolycerasoidol and (6E,10E) Isopolycerasoidol Methyl Ester, Prenylated Benzopyran Derivatives from Pseuduvaria monticola Induce Mitochondrial-Mediated Apoptosis in Human Breast Adenocarcinoma Cells.

Phytochemicals from Pseuduvaria species have been reported to display a wide range of biological activities. In the present study, a known benzopyran derivative, (6E,10E) isopolycerasoidol (1), and a new benzopyran derivative, (6E,10E) isopolycerasoidol methyl ester (2), were isolated from a methanol extract of Pseuduvaria monticola leaves. The structures of the isolated compounds were elucidated by spectroscopic methods including 1D and 2D NMR, IR, UV, and LCMS-QTOF, and by comparison with previously published data. The anti-proliferative and cytotoxic effects of these compounds on human breast cancer cell-lines (MCF-7 and MDA-MB-231) and a human normal breast epithelial cell line (MCF-10A) were investigated. MTT results revealed both (1) and (2) were efficient in reducing cell viability of breast cancer cells. Flow cytometry analysis demonstrated that (1) and (2) induced cell death via apoptosis, as demonstrated by an increase in phosphotidylserine exposure. Both compounds elevated ROS production, leading to reduced mitochondrial membrane potential and increased plasma membrane permeability in breast cancer cells. These effects occurred concomitantly with a dose-dependent activation of caspase 3/7 and 9, a down-regulation of the anti-apoptotic gene BCL2 and the accumulation of p38 MAPK in the nucleus. Taken together, our data demonstrate that (1) and (2) induce intrinsic mitochondrial-mediated apoptosis in human breast cancer cells, which provides the first pharmacological evidence for their future development as anticancer agents.

Expression of miR-145 in breast cancer and its role in invasion and migration of breast cancer cells

Objective To investigate the expression of microRNA–21 (miR–21) in breast cancer cell lines and serum of patients with breast cancer and the impact on the invasion and migration of breast cancer cells. Methods From Jan 2013 to Feb 2014, miR–21 expression were determined by fluorescent quantity polymerase chain reaction (FQ–PCR) in 4 breast cell lines (HBL–100, MCF–7, MDA–MB–231 and MDA–MB–468) and in serum from breast cancer patients (n=56), breast benign disease patients (n=39) andhealth controls (n=45). The characteristics of cell invasion and migration were examined by transwellinvasion and migration assay afterbreast cancer cell line MDA–MB–231 were transfectedwith miR–21 inhibitor or negative control by lipofectamin. The t test was used to analysis the normal distribution data. Results FQ–PCR results showed that the relative expression of miR–21 in the normal breast epithelial cell line HBL–100 was 1.01 ± 0.04, in the breast cancer cell line MCF–7, MDA–MB–231 and MDA–MB–468 were 1.99 ± 0.11, 4.02 ± 0.38 and 3.73 ± 0.79 respectively. Compared with the normal controls, miR–21 were highly expressed in the three breast cancer cell lines, the difference was statistically significant (t=9.01, 9.20 and 4.55, respectively, P<0.01); and the miR–21 was highly expressed in invasive and metastatic breast cancer cell lines (MDA–MB–231 and MDA–MB–468), compared with weakly invasive breast cancer cell line MCF–7, the difference was statistically significant (t values were 6.14 and 2.91, P<0.05), suggesting that miR–21 is highly expressed in breast cancer cells, and is closely related to the invasion and metastasis. The relative expression of miR–21 in serum of breast cancer was 2.63 (1.57–4.59), in benign breast disease group was 1.34 (1.01–1.78), in healthy control group was 0.81 (0.52–1.59), the miR–21 expression in the serum of breast cancer patients was significantly higher than in patients with benign lesions and normal control group (U values were 208 and 279, P<0.01), whereas no significant difference in serum in patients with benign lesions and normal control group, the miR–21 expression in the serum of breast cancer patients with lymph node metastasis (U=95, P=0.19) was 3.55 (2.44–5.26), significantly higher than those without lymph node metastasis [2.11(1.59–3.25), U=216, P=0.021]. The results of invasion and migration assay showed that cells treated with miR–21 inhibitor invasion was: 44 ± 18, the number of cell migration was: 98 ± 22, while the negative control treated cells after invasion was: 133 ± 44, migration cell number: 255 ± 35; miR–21 inhibitor treatment compared with the negative control, cell invasion and migration was also significantly decreased (t values were 5.46 and 9.08, P<0.01). The cell invasion and migration assay indicated the numbers of MDA–MB–231 cells, which invaded or migrated to lower chamber, were 44±18 and 98±22 respectively after miR–21 inhibitor was applied, The numbers of invaded or migrated cells were 133±44 and 255±35 when the negative control was applied. The ability of cell invasion and migration was decreased significantly in the inhibitor group compared with the negative group (tvalue separately was 5.46, 9.08, P<0.01). The capacity of breast cancer cell invasion and migrationwas significantly decreased after transfection ofmiR–21 inhibitor. Conclusions MiR–21 is highly expressed in breast cancer cell lines and breast cancer patients′ serum. Altered expression of miR–21 maybeplays an important role in breast cancer invasion and migration. MiR–21 may serve as new biomarker to early detectionand prognosis estimation of breast cancer. (Chin J Lab Med, 2015, 38: 186–190) Key words: Breast neoplasms; microRNAs; Neoplasm metastasis; Tumor markers, biological

FOXP1 regulation via the PI3K/Akt/p70S6K signaling pathway in breast cancer cells.

Loss of Forkhead box P1 (FOXP1) protein expression confers a poor prognosis in sporadic and familial breast cancer patients, and the FOXP1 gene maps to a tumor suppressor locus at chromosome 3p14. Although correlation studies have indicated that FOXP1 has a role in tumor suppression, determination of the regulatory mechanism of FOXP1 is required to establish its function in breast cancer. It has previously been identified that FOXP1 is regulated by estrogen in breast cancer and that treatment with bisphenol A is effective for regulating the transformation of the normal human breast epithelial cell line, MCF-10F. In addition, FOXO-regulated activation of FOXP1 inhibits the apoptosis of MCF-10F cells following tamoxifen and Akt inhibitor VIII administration. The present study indicates that FOXP1 regulation occurs via a PI3K/Akt/p70S6 kinase (p70S6K) signaling pathway. Following treatment with wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3K)/Akt, MCF7 and MDA-MB-231 breast cancer cells demonstrated decreased FOXP1 protein expression levels; this result was also observed in the small interfering (si)RNA silencing of Akt. By contrast, overexpression of Akt resulted in increased FOXP1 protein expression levels in the MDA-MB-231 cells compared with the control cell lysates. Furthermore, treatment with rapamycin, a specific inhibitor of the mammalian target of rapamycin/p70S6K cascade, resulted in decreased FOXP1 expression in the MCF7 cells, but not in the MDA-MB-231 cells, which were resistant to rapamycin-induced inhibition. In addition, silencing of p70S6K using siRNA produced a marked decrease in FOXP1 expression. These data indicate that FOXP1 protein expression is regulated by a PI3K/Akt/p70S6K signaling cascade in breast cancer.

Expression of Tropomyosin 1 Gene Isoforms in Human Breast Cancer Cell Lines.

Nine malignant breast epithelial cell lines and 3 normal breast cell lines were examined for stress fiber formation and expression of TPM1 isoform-specific RNAs and proteins. Stress fiber formation was strong (++++) in the normal cell lines and varied among the malignant cell lines (negative to +++). Although TPM1γ and TPM1δ were the dominant transcripts of TPM1, there was no clear evidence for TPM1δ protein expression. Four novel human TPM1 gene RNA isoforms were discovered (λ, μ, ν, and ξ), which were not identified in adult and fetal human cardiac tissues. TPM1λ was the most frequent isoform expressed in the malignant breast cell lines, and it was absent in normal breast epithelial cell lines. By western blotting, we were unable to distinguish between TPM1γ, λ, and ν protein expression, which were the only TPM1 gene protein isoforms potentially expressed. Some malignant cell lines demonstrated increased or decreased expression of these isoforms relative to the normal breast cell lines. Stress fiber formation did not correlate with TPM1γ RNA expression but significantly and inversely correlated with TPM1δ and TPM1λ expression, respectively. The exact differences in expression of these novel isoforms and their functional properties in breast epithelial cells will require further study.

MiR-27a modulates radiosensitivity of triple-negative breast cancer (TNBC) cells by targeting CDC27.

BackgroundMiR-27a is significantly overexpressed in triple-negative breast cancer (TNBC). However, the exact biological function of MiR-27a in TNBC is not fully understood. In this study, we verified miR-27a expression in TNBC cells and explored how its overexpression modulates radiosensitivity of the cells.Material/MethodqRT-PCR analysis was performed to study miR-27a expression in TNBC lines MDA-MB-435 and MDA-MB-231 and in normal human breast epithelial cell line MCF10A. Dual luciferase assay was performed to verify a putative downstream target of miR-27a, CDC27. CCK-8 assay was used to assess the influence of miR-27a-CDC27 axis on cell proliferation under irradiation (IR) treatment.ResultsWe confirmed significantly higher miR-27a expression in 2 TNBC cell lines – MDA-MB-435 and MDA-MB-231 – than in human breast epithelial cell line MCF10A. miR-27a could modulate proliferation and radiosensitivity of TNBC cells. CDC-27 is a direct target of miR-27a and its downregulation conferred increased radioresistance of the cells.ConclusionsThe miR-27a-CDC27 axis might play an important role in modulating response to radiotherapy in TNBC cells. Testing miR-27a expression might be a useful way to identify a subgroup of patients who will benefit from an IR-based therapeutic approach.

Experimental validation of predicted subcellular localizations of human proteins.

BackgroundComputational methods have been widely used for the prediction of protein subcellular localization. However, these predictions are rarely validated experimentally and as a result remain questionable. Therefore, experimental validation of the predicted localizations is needed to assess the accuracy of predictions so that such methods can be confidently used to annotate the proteins of unknown localization. Previously, we published a method called ngLOC that predicts the localization of proteins targeted to ten different subcellular organelles. In this short report, we describe the accuracy of these predictions using experimental validations.FindingsWe have experimentally validated the predicted subcellular localizations of 114 human proteins corresponding to nine different organelles in normal breast and breast cancer cell lines using live cell imaging/confocal microscopy. Target genes were cloned into expression vectors as GFP fusions and cotransfected with RFP-tagged organelle-specific gene marker into normal breast epithelial and breast cancer cell lines. Subcellular localization of each target protein is confirmed by colocalization with a co-expressed organelle-specific protein marker. Our results showed that about 82.5% of the predicted subcellular localizations coincided with the experimentally validated localizations. The highest agreement was found in the endoplasmic reticulum proteins, while the cytoplasmic location showed the least concordance. With the exclusion of cytoplasmic location, the average prediction accuracy increased to 90.4%. In addition, there was no difference observed in the protein subcellular localization between normal and cancer breast cell lines.ConclusionsThe experimentally validated accuracy of ngLOC method with (82.5%) or without cytoplasmic location (90.4%) nears the prediction accuracy of 89%. These results demonstrate that the ngLOC method can be very useful for large-scale annotation of the unknown subcellular localization of proteins.Electronic supplementary materialThe online version of this article (doi:10.1186/1756-0500-7-912) contains supplementary material, which is available to authorized users.

Transducin (β)-like 1 X-linked receptor 1 promotes proliferation and tumorigenicity in human breast cancer via activation of beta-catenin signaling.

IntroductionTransducin (β)-like 1 X-linked receptor 1(TBLR1) is an F-box-like and WD repeat-containing protein which functions as a switch in transcriptional activation, However, the clinical significance and biological role of TBLR1 in breast cancer remains largely unknown.MethodsWestern blotting, immunocytochemistry and real-time PCR were used to evaluate TBLR1 expression in normal breast epithelial cells and breast cancer cell lines, clinical tissue samples and adjacent nontumor tissues, and in 214 paraffin-embedded specimens. Statistical analyses were used to test for the prognostic and diagnostic associations. The biological role of TBLR1 -induced proliferation and tumorigenicity in breast cancer cells was explored in vitro and in vivo. The effect of TBLR1 on the expression of cyclin D1 and β-catenin signaling was examined by Western blotting, luciferase reporter assay and by several immunoprecipitation techniques.ResultsTBLR1 was significantly upregulated in breast cancer cells and tissues compared to normal control samples. Immunohistochemical analysis revealed high expression of TBLR1 in 113 of 214 (52.8%) paraffin-embedded archival breast cancer. The overall expression level of TBLR1 was significantly correlated with clinical stage (P <0.001), the tumor classification (P <0.001), node classification (P =0.024), and metastasis classification (P = 0.004), histological grade (P = 0.044), as well as with the expression level of c-erbB2 (P = 0.036) and Ki-67 (P <0.001). Patients with higher TBLR1 expression had shorter overall survival time, whereas patients with lower TBLR1 expression had better survival. Multivariate analysis suggested that TBLR1 expression might be an independent prognostic indicator for the survival of breast cancer patients. TBLR1 overexpression promoted, whereas TBLR1 silencing inhibited, proliferation and tumorigenicity in breast cancer cells both in vitro and in vivo. We found that TBLR1 expression was implicated in the upregulation of cyclin D1, phosphorylation of cell-cycle control protein Rb (pRb) and activation of β-catenin signaling in breast cancer.ConclusionsTBLR1 plays a key role in the development and progression of breast cancer cells via cyclin D1-transactivation and activation of the β-catenin signaling pathway. TBLR1 may be a novel prognostic marker and a potential therapeutic target in the treatment human breast cancer.Electronic supplementary materialThe online version of this article (doi:10.1186/s13058-014-0465-z) contains supplementary material, which is available to authorized users.

Diallyl sulfide inhibits diethylstilbestrol induced DNA damage in human breast epithelial cells (MCF-10A)

Breast cancer is the second leading cause of cancer deaths in women in the United States. Diethylstilbestrol (DES) is a synthetic estrogen that has been shown to cause cancer in animals and humans, altering cell viability as well as inducing DNA damage. Diallyl sulfide (DAS) is a garlic organosulfide that has been shown to inhibit both the initiation and promotion phases of cancer in vivo and in vitro, as well as reduce the risk of cancer in epidemiological studies. MCF-10A cells, regarded as a normal breast epithelial cell line, were treated with varying concentrations of DES, DAS or various dose combinations of DES and DAS concomitantly, and assessed for cell viability, DNA strand breaks, and lipid peroxidation. DES (10μM) in combination with 1, 10, or 100μM DAS resulted in a 31%, 34%, or 36% respective increase in cell viability compared to the DES treatment alone, after 24h. At the same time point, 1, 10, and 100μM DAS were all effective in significantly reducing DES (100μM)-induced strand breaks to near that of the vehicle control. Additionally, 1μM DAS was effective in significantly reducing DES (100μM)-induced lipid peroxidation after 3h. The results of this research suggest that DAS is effective in recovering cell viability, attenuating DNA strand breaks, and decreasing lipid peroxidation in MCF-10A cells.

A biomaterial model of tumor stromal microenvironment promotes mesenchymal morphology but not epithelial to mesenchymal transition in epithelial cells

The stromal tissue surrounding most carcinomas is comprised of an extracellular matrix densely packed with collagen-I fibers, which are often highly aligned in metastatic disease. Here we developed an in vitro model to test the effect of an aligned fibrous environment on cancer cell morphology and behavior, independent of collagen ligand presentation. We grew cells on a biomimetic surface of aligned electrospun poly-l-lactic acid (PLLA) fibers and then examined the effect of this environment on growth rate, morphology, cytoskeletal organization, biochemical and genetic markers of epithelial to mesenchymal transition (EMT), cell surface adhesion, and cell migration. We grew a phenotypically normal breast epithelial cell line (MCF10A) and an invasive breast cancer cell line (MDA-MB-231) on three different substrates: typical flat culture surface (glass or plastic), flat PLLA (glass coated with PLLA) or electrospun PLLA fibers. Cells of both types adopted a more mesenchymal morphology when grown on PLLA fibers, and this effect was exaggerated in the more metastatic-like MDA-MB-231 cells. However, neither cell type underwent the changes in gene expression indicative of EMT despite the changes in cell shape, nor did they exhibit the decreased adhesive strength or increased migration typical of metastatic cells. These results suggest that changes in cell morphology alone do not promote a more mesenchymal phenotype and consequently that the aligned fibrous environment surrounding epithelial cancers may not promote EMT solely through topographical cues.

MiR-200c inhibits autophagy and enhances radiosensitivity in breast cancer cells by targeting UBQLN1.

Radioresistance is a major challenge during the treatment of breast cancer. A further understanding of the mechanisms of radioresistance could provide strategies to address this challenge. In our study, we compared the expression of miR-200c in four distinct breast cancer cell lines: two representative basal cancer cells (MDA-MB-231 and BT549) vs. two representative luminal cancer cells (MCF-7 and BT474). The results revealed practically lower expression of miR-200c in the two basal cancer cell lines and higher expression of miR-200c in luminal cancer cells compared to the normal breast epithelial cell line MCF-10A. Ectopic expression of miR-200c in MDA-MB-231 cells inhibited irradiation-induced autophagy and sensitized the breast cancer cells to irradiation. We also identified UBQLN1 as a direct functional target of miR-200c involved in irradiation-induced autophagy and radioresistance. In 35 human breast cancer tissue samples, we detected an inverse correlation between the expression of miR-200c vs. UBQLN1 and LC3. These results indicate that the identified miR-200c/UBQLN1-mediated autophagy pathway may help to elucidate radioresistance in human breast cancer and might represent a therapeutic strategy.

Histone Deacetylase Inhibitors Improve the Replication of Oncolytic Herpes Simplex Virus in Breast Cancer Cells

New therapies are needed for metastatic breast cancer patients. Oncolytic herpes simplex virus (oHSV) is an exciting therapy being developed for use against aggressive tumors and established metastases. Although oHSV have been demonstrated safe in clinical trials, a lack of sufficient potency has slowed the clinical application of this approach. We utilized histone deacetylase (HDAC) inhibitors, which have been noted to impair the innate antiviral response and improve gene transcription from viral vectors, to enhance the replication of oHSV in breast cancer cells. A panel of chemically diverse HDAC inhibitors were tested at three different doses (<, = , and >LD50) for their ability to modulate the replication of oHSV in breast cancer cells. Several of the tested HDAC inhibitors enhanced oHSV replication at low multiplicity of infection (MOI) following pre-treatment of the metastatic breast cancer cell line MDA-MB-231 and the oHSV-resistant cell line 4T1, but not in the normal breast epithelial cell line MCF10A. Inhibitors of class I HDACs, including pan-selective compounds, were more effective for increasing oHSV replication compared to inhibitors that selectively target class II HDACs. These studies demonstrate that select HDAC inhibitors increase oHSV replication in breast cancer cells and provides support for pre-clinical evaluation of this combination strategy.

Novel transcripts from a distinct promoter that encode the full-length AKT1 in human breast cancer cells

BackgroundThe serine-threonine kinase AKT1 plays essential roles during normal mammary gland development as well as the initiation and progression of breast cancer. AKT1 is generally considered a ubiquitously expressed gene, and its persistent activation is transcriptionally controlled by regulatory elements characteristic of housekeeping gene promoters. We recently identified a novel Akt1 transcript in mice (Akt1m), which is induced by growth factors and their signal transducers of transcription from a previously unknown promoter. The purpose of this study was to examine whether normal and neoplastic human breast epithelial cells express an orthologous AKT1m transcript and whether its expression is deregulated in cancer cells.MethodsInitial sequence analyses were performed using the UCSC Genome Browser and GenBank to assess the potential occurrence of an AKT1m transcript variant in human cells and to identify conserved promoter sequences that are orthologous to the murine Akt1m. Quantitative RT-PCR was used to determine the transcriptional activation of AKT1m in mouse mammary tumors as well as 41 normal and neoplastic human breast epithelial cell lines and selected primary breast cancers.ResultsWe identified four new AKT1 transcript variants in human breast cancer cells that are orthologous to the murine Akt1m and that encode the full-length kinase. These transcripts originate from an alternative promoter that is conserved between humans and mice. Akt1m is upregulated in the majority of luminal-type and basal-type mammary cancers in four different genetically engineered mouse models. Similarly, a subset of human breast cancer cell lines and primary breast cancers exhibited a higher expression of orthologous AKT1m transcripts.ConclusionsThe existence of an alternative promoter that drives the expression of the unique AKT1m transcript may provide a mechanism by which the levels of AKT1 can be temporally and spatially regulated at particular physiological states, such as cancer, where a heightened activity of this kinase is required.

Role of Sphk1 in the malignant transformation of breast epithelial cells and breast cancer progression.

The ojective of the following study is to investigate the role of sphingosine kinase 1 (Sphk1) in the malignant transformation of breast epithelial cells and breast cancer progression and its mechanism. Immunohistochemistry was performed to detect Sphk1 and E-cadherin (E-cad) in resected breast samples. Sphk1 was transfected in normal human breast epithelial cell line (MCF-10A) by Lentivirus and silenced in breast cancer cell line (MCF-7) using small interfering ribonucleic acid. The effect of tumor necrosis factor alpha (TNF-α) and/or N, N-dimethylsphingosine (DMS) on the Sphk1 and E-cad expression, MCF-10A cell proliferation and invasion was investigated. Real time-polymerase chain reaction and western-blot was used to detect messenger ribonucleic acid and protein. Cell counting kit-8 and transwell were used to measure cell proliferation and invasion. Sphk1 was positive expression in 114 breast tumors (75.50%) but negative in fibroadenomas. The expression of E-cad and Sphk1 were negatively correlated and E-cad (-)/Sphk1 (+) carriers showed higher ratio of axillary lymph node metastasis than E-cad (+)/Sphk1 (-) carriers. Overexpression of Sphk1 in MCF-10A reduced E-cad expression and improved cell proliferation and invasion, but knockdown of Sphk1 in MCF-7 decreased cell proliferation and invasion. TNF-α increased Sphk1 expression, enhanced the ability of Sphk1 in decreasing E-cad expression, which could be blocked by DMS. TNF-α promoted MCF-10A cell proliferation and invasion. Sphk1 plays an important role in the malignant transformation of breast epithelial cells and modulates breast cancer metastasis through the regulation of E-cad expression. TNF-α can up-regulate Sphk1 expression and reduce E-cad expression through Sphk1, which can be blocked by DMS. TNF-α/Sphk1/E-cad pathway may be a newly discovered pathway and plays an important role in tumorigenesis and metastasis.