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1.
Hongmei Sun Jun Jia Xiaoli Wang Bo Ma Lijun Di Guohong Song Jun Ren 《Clinical & translational oncology》2013,15(1):46-54
Background
Recent studies suggest that the relationship between cancer stem cells (CSCs) and the vascular niche may be bidirectional; the niche can support the growth and renewal of CSCs, and CSCs may contribute to the maintenance of the niche. There is little knowledge concerning the role of breast cancer stem cells in promoting tumor angiogenesis.Aim
For human breast cancers, CSCs have been shown to be associated with a CD44+/CD24 ? phenotype. We investigated the potential activities of CD44+/CD24 ? breast cancer stem cells in promoting tumor angiogenesis.Methods
The expression of pro-angiogenic genes was determined by quantitative real-time RT-PCR. Endothelial cell migration assays were employed to evaluate effects of conditioned media from CD44+/CD24 ? on human umbilical vein endothelial cells. A chorioallantoic membrane (CAM) assay was used to study the potential of CD44+/CD24 ? cells to promote angiogenesis.Results
In our study, CD44+/CD24 ? cells expressed elevated levels of pro-angiogenic factors compared with CD44+/CD24+ cells. CD44+/CD24 ? cell-conditioned media significantly increased endothelial cell migration. Breast cancer cell lines enriched with CD44+/CD24 ? cells were more pro-angiogenic in the CAM assay than those lacking a CD44+/CD24 ? subpopulation. CD44+/CD24 ? cells sorted from MCF-7 cell lines were more pro-angiogenic in a CAM assay than CD44+/CD24+ cells. Furthermore, the VEGF concentration was significantly higher in CD44+/CD24 ? cell-conditioned media than in CD44+/CD24+ cell-conditioned media. The pro-angiogenic effect of CD44+/CD24 ? cells on endothelial cells was abolished by bevacizumab.Conclusion
Our findings demonstrate that CD44+/CD24 ? breast cancer stem cells have substantial pro-angiogenic potential and activity. This provides new insights to explore in the development of targeted therapies. 相似文献2.
Introduction
Triple-negative breast cancer (TNBC) high rate of relapse is thought to be due to the presence of tumor-initiating cells (TICs), molecularly defined as being CD44high/CD24-/low. TICs are resilient to chemotherapy and radiation. However, no currently accepted molecular target exists against TNBC and, moreover, TICs. Therefore, we sought the identification of kinase targets that inhibit TNBC growth and eliminate TICs.Methods
A genome-wide human kinase small interfering RNA (siRNA) library (691 kinases) was screened against the TNBC cell line SUM149 for growth inhibition. Selected siRNAs were then tested on four different breast cancer cell lines to confirm the spectrum of activity. Their effect on the CD44high subpopulation and sorted CD44high/CD24-/low cells of SUM149 also was studied. Further studies were focused on polo-like kinase 1 (PLK1), including its expression in breast cancer cell lines, effect on the CD44high/CD24-/low TIC subpopulation, growth inhibition, mammosphere formation, and apoptosis, as well as the activity of the PLK1 inhibitor, BI 2536.Results
Of the 85 kinases identified in the screen, 28 of them were further silenced by siRNAs on MDA-MB-231 (TNBC), BT474-M1 (ER+/HER2+, a metastatic variant), and HR5 (ER+/HER2+, a trastuzumab-resistant model) cells and showed a broad spectrum of growth inhibition. Importantly, 12 of 28 kinases also reduced the CD44high subpopulation compared with control in SUM149. Further tests of these 12 kinases directly on a sorted CD44high/CD24-/low TIC subpopulation of SUM149 cells confirmed their effect. Blocking PLK1 had the greatest growth inhibition on breast cancer cells and TICs by about 80% to 90% after 72 hours. PLK1 was universally expressed in breast cancer cell lines, representing all of the breast cancer subtypes, and was positively correlated to CD44. The PLK1 inhibitor BI 2536 showed similar effects on growth, mammosphere formation, and apoptosis as did PLK1 siRNAs. Finally, whereas paclitaxel, doxorubicin, and 5-fluorouracil enriched the CD44high/CD24-/low population compared with control in SUM149, subsequent treatment with BI 2536 killed the emergent population, suggesting that it could potentially be used to prevent relapse.Conclusion
Inhibiting PLK1 with siRNA or BI 2536 blocked growth of TNBCs including the CD44high/CD24-/low TIC subpopulation and mammosphere formation. Thus, PLK1 could be a potential therapeutic target for the treatment of TNBC as well as other subtypes of breast cancer. 相似文献3.
Masahiro Uchino Hiroko Kojima Kenta Wada Mika Imada Fumitoshi Onoda Hiroyuki Satofuka Takahiko Utsugi Yasufumi Murakami 《BMC cancer》2010,10(1):414
Background
In breast cancer cells, the metastatic cell state is strongly correlated to epithelial-to-mesenchymal transition (EMT) and the CD44+/CD24- stem cell phenotype. However, the MCF-7 cell line, which has a luminal epithelial-like phenotype and lacks a CD44+/CD24- subpopulation, has rare cell populations with higher Matrigel invasive ability. Thus, what are the potentially important differences between invasive and non-invasive breast cancer cells, and are the differences related to EMT or CD44/CD24 expression?Methods
Throughout the sequential selection process using Matrigel, we obtained MCF-7-14 cells of opposite migratory and invasive capabilities from MCF-7 cells. Comparative analysis of epithelial and mesenchymal marker expression was performed between parental MCF-7, selected MCF-7-14, and aggressive mesenchymal MDA-MB-231 cells. Furthermore, using microarray expression profiles of these cells, we selected differentially expressed genes for their invasive potential, and performed pathway and network analysis to identify a set of interesting genes, which were evaluated by RT-PCR, flow cytometry or function-blocking antibody treatment.Results
MCF-7-14 cells had enhanced migratory and invasive ability compared with MCF-7 cells. Although MCF-7-14 cells, similar to MCF-7 cells, expressed E-cadherin but neither vimentin nor fibronectin, β-catenin was expressed not only on the cell membrane but also in the nucleus. Furthermore, using gene expression profiles of MCF-7, MCF-7-14 and MDA-MB-231 cells, we demonstrated that MCF-7-14 cells have alterations in signaling pathways regulating cell migration and identified a set of genes (PIK3R1, SOCS2, BMP7, CD44 and CD24). Interestingly, MCF-7-14 and its invasive clone CL6 cells displayed increased CD44 expression and downregulated CD24 expression compared with MCF-7 cells. Anti-CD44 antibody treatment significantly decreased cell migration and invasion in both MCF-7-14 and MCF-7-14 CL6 cells as well as MDA-MB-231 cells.Conclusions
MCF-7-14 cells are a novel model for breast cancer metastasis without requiring constitutive EMT and are categorized as a "metastable phenotype", which can be distinguished from both epithelial and mesenchymal cells. The alterations and characteristics of MCF-7-14 cells, especially nuclear β-catenin and CD44 upregulation, may characterize invasive cell populations in breast cancer.4.
Mingzhu Huang Yuqing Li Huanle Zhang Feifei Nan 《Journal of experimental & clinical cancer research : CR》2010,29(1):80
Background
Breast cancer stem cells (BCSCs) have been recently identified in breast carcinoma as CD44+CD24- cells, which exclusively retain tumorigenic activity and display stem cell-like properties. Using a mammosphere culture technique, MCF7 mammosphere cells are found to enrich breast cancer stem-like cells expressing CD44+CD24-. The stromal cells are mainly constituted by fibroblasts within a breast carcinoma, yet little is known of the contributions of the stromal cells to BCSCs.Methods
Carcinoma-associated fibroblasts (CAFs) and normal fibroblasts (NFs) were isolated and identified by immunohistochemistry. MCF7 mammosphere cells were co-cultured with different stromal fibroblasts by a transwell cocultured system. Flow cytometry was used to measure CD44 and CD24 expression status on MCF7. ELISA (enzyme-linked immunosorbent assay) was performed to investigate the production of stromal cell-derived factor 1 (SDF-1) in mammosphere cultures subject to various treatments. Mammosphere cells were injected with CAFs and NFs to examine the efficiency of tumorigenity in NOD/SCID mice.Results
CAFs derived from breast cancer patients were found to be positive for α-smooth muscle actin (α-SMA), exhibiting the traits of myofibroblasts. In addition, CAFs played a central role in promoting the proliferation of CD44+CD24- cells through their ability to secrete SDF-1, which may be mediated to SDF-1/CXCR4 signaling. Moreover, the tumorigenicity of mammosphere cells with CAFs significantly increased as compared to that of mammosphere cells alone or with NFs.Conclusion
We for the first time investigated the effects of stromal fibroblasts on CD44+CD24- cells and our findings indicated that breast CAFs contribute to CD44+CD24- cell proliferation through the secretion of SDF-1, and which may be important target for therapeutic approaches. 相似文献5.
Human breast cancer cell lines contain stem-like cells that self-renew, give rise to phenotypically diverse progeny and survive chemotherapy 总被引:4,自引:0,他引:4
Introduction
The phenotypic and functional differences between cells that initiate human breast tumors (cancer stem cells) and those that comprise the tumor bulk are difficult to study using only primary tumor tissue. We embarked on this study hypothesizing that breast cancer cell lines would contain analogous hierarchical differentiation programs to those found in primary breast tumors.Methods
Eight human breast cell lines (human mammary epithelial cells, and MCF10A, MCF7, SUM149, SUM159, SUM1315 and MDA.MB.231 cells) were analyzed using flow cytometry for CD44, CD24, and epithelial-specific antigen (ESA) expression. Limiting dilution orthotopic injections were used to evaluate tumor initiation, while serial colony-forming unit, reconstitution and tumorsphere assays were performed to assess self-renewal and differentiation. Pulse-chase bromodeoxyuridine (5-bromo-2-deoxyuridine [BrdU]) labeling was used to examine cell cycle and label-retention of cancer stem cells. Cells were treated with paclitaxol and 5-fluorouracil to test selective resistance to chemotherapy, and gene expression profile after chemotherapy were examined.Results
The percentage of CD44+/CD24- cells within cell lines does not correlate with tumorigenicity, but as few as 100 cells can form tumors when sorted for CD44+/CD24-/low/ESA+. Furthermore, CD44+/CD24-/ESA+ cells can self-renew, reconstitute the parental cell line, retain BrdU label, and preferentially survive chemotherapy.Conclusion
These data validate the use of cancer cell lines as models for the development and testing of novel therapeutics aimed at eradicating cancer stem cells. 相似文献6.
Jian-guo Sun Rong-xia Liao Jun Qiu Jun-yu Jin Xin-xin Wang Yu-zhong Duan Fang-lin Chen Ping Hao Qi-chao Xie Zhi-xin Wang De-zhi Li Zheng-tang Chen Shao-xiang Zhang 《Journal of experimental & clinical cancer research : CR》2010,29(1):174
Background
This study aimed to determine the miRNA profile in breast cancer stem cells (BCSCs) and to explore the functions of characteristic BCSC miRNAs.Methods
We isolated ESA+CD44+CD24-/low BCSCs from MCF-7 cells using fluorescence-activated cell sorting (FACS). A human breast cancer xenograft assay was performed to validate the stem cell properties of the isolated cells, and microarray analysis was performed to screen for BCSC-related miRNAs. These BCSC-related miRNAs were selected for bioinformatic analysis and target prediction using online software programs.Results
The ESA+CD44+CD24-/low cells had up to 100- to 1000-fold greater tumor-initiating capability than the MCF-7 cells. Tumors initiated from the ESA+CD44+CD24-/low cells were included of luminal epithelial and myoepithelial cells, indicating stem cell properties. We also obtained miRNA profiles of ESA+CD44+CD24-/low BCSCs. Most of the possible targets of potential tumorigenesis-related miRNAs were oncogenes, anti-oncogenes or regulatory genes.Conclusions
We identified a subset of miRNAs that were differentially expressed in BCSCs, providing a starting point to explore the functions of these miRNAs. Evaluating characteristic BCSC miRNAs represents a new method for studying breast cancer-initiating cells and developing therapeutic strategies aimed at eradicating the tumorigenic subpopulation of cells in breast cancer. 相似文献7.
Background
A large proportion of breast cancer patients are resistant to radiotherapy, which is a mainstay treatment for this malignancy, but the mechanisms of radioresistance remain unclear.Methods and materials
To evaluate the role of miRNAs in radioresistance, we established two radioresistant breast cancer cell lines MCF-7R and T-47DR derived from parental MCF-7 and T-47D. Moreover, miRNA microarray, quantitative RT-PCR analysis, luciferase reporter assay and western blotting were used.Results
We found that miR-668 was most abundantly expressed in radioresistant cells MCF-7R and T-47DR. miR-668 knockdown reversed radioresistance of MCF-7R and T-47DR, miR-668 overexpression enhanced radioresistance of MCF-7 and T-47D cells. Mechanically, bioinformatics analysis combined with experimental analysis demonstrated IκBα, a tumor-suppressor as well as an NF-κB inhibitor, was a direct target of miR-668. Further, miR-668 overexpression inhibited IκBα expression, activated NF-κB, thus, increased radioresistance of MCF-7 and T-47D cells. Conversely, miR-668 knockdown restored IκBα expression, suppressed NF-κB, increased radiosensitivity of MCF-7R and T-47DR cells.Conclusion
Our findings suggest miR-668 is involved in the radioresistance of breast cancer cells and miR-668-IκBα-NF-κB axis may be a novel candidate for developing rational therapeutic strategies for human breast cancer treatment.8.
Brca1 breast tumors contain distinct CD44+/CD24- and CD133+ cells with cancer stem cell characteristics 总被引:2,自引:0,他引:2
Wright MH Calcagno AM Salcido CD Carlson MD Ambudkar SV Varticovski L 《Breast cancer research : BCR》2008,10(1):R10-16
Introduction
Whether cancer stem cells occur in BRCA1-associated breast cancer and contribute to therapeutic response is not known.Methods
We generated and characterized 16 cell lines from five distinct Brca1deficient mouse mammary tumors with respect to their cancer stem cell characteristics.Results
All cell lines derived from one tumor included increased numbers of CD44+/CD24- cells, which were previously identified as human breast cancer stem cells. All cell lines derived from another mammary tumor exhibited low levels of CD44+/CD24- cells, but they harbored 2% to 5.9% CD133+ cells, which were previously associated with cancer stem cells in other human and murine tumors. When plated in the absence of attachment without presorting, only those cell lines that were enriched in either stem cell marker formed spheroids, which were further enriched in cells expressing the respective cancer stem cell marker. In contrast, cells sorted for CD44+/CD24- or CD133+ markers lost their stem cell phenotype when cultured in monolayers. As few as 50 to 100 CD44+/CD24- or CD133+ sorted cells rapidly formed tumors in nonobese diabetic/severe combined immunodeficient mice, whereas 50-fold to 100-fold higher numbers of parental or stem cell depleted cells were required to form few, slow-growing tumors. Expression of stem cell associated genes, including Oct4, Notch1, Aldh1, Fgfr1, and Sox1, was increased in CD44+/CD24- and CD133+ cells. In addition, cells sorted for cancer stem cell markers and spheroid-forming cells were significantly more resistant to DNA-damaging drugs than were parental or stem cell depleted populations, and they were sensitized to the drugs by the heat shock protein-90 inhibitor 17-DMAG (17-dimethylaminoethylamino-17-demethoxygeldanamycin hydrochloride).Conclusion
Brca1-deficient mouse mammary tumors harbor heterogeneous cancer stem cell populations, and CD44+/CD24- cells represent a population that correlates with human breast cancer stem cells. 相似文献9.
CD44 targets Na+/H+ exchanger 1 to mediate MDA-MB-231 cells' metastasis via the regulation of ERK1/2
G Chang J Wang H Zhang Y Zhang C Wang H Xu H Zhang Y Lin L Ma Q Li T Pang 《British journal of cancer》2014,110(4):916-927
Background:
CD44, a transmembrane glycoprotein expressed in a variety of cells and tissues, has been implicated in tumour metastasis. But the molecular mechanisms of CD44-mediated tumour cell metastasis remain to be elucidated.Methods:
The downregulation of CD44 was determined by immunofluorescence. Moreover, the motility of breast cancer cells was detected by wound-healing and transwell experiments. Then the spontaneous metastasis of CD44-silenced MDA-MB-231 cells was tested by histology with BALB/c nude mice.Results:
A positive correlation between CD44 and Na+/H+ exchanger isoform 1 (NHE1) was found in two breast cancer cells. CD44 downregulation could inhibit the metastasis of MDA-MB-231 cells and the expressions of Na+/H+ exchanger 1. Moreover, CD44 overexpression upregulated the metastasis of MCF-7 cells, but the elevated metastatic ability was then inhibited by Cariporide. Interestingly, during these processes only the p-ERK1/2 was suppressed by CD44 downregulation and the expression of matrix metalloproteinases and metastatic capacity of MDA-MB-231 cells were greatly inhibited by the MEK1 inhibitor PD98059, which even had a synergistic effect with Cariporide. Furthermore, CD44 downregulation inhibits breast tumour outgrowth and spontaneous lung metastasis.Conclusions:
Taken together, this work indicates that CD44 regulates the metastasis of breast cancer cells through regulating NHE1 expression, which could be used as a novel strategy for breast cancer therapy. 相似文献10.
Cross-priming of cyclin B1, MUC-1 and survivin-specific CD8+ T cells by dendritic cells loaded with killed allogeneic breast cancer cells 总被引:1,自引:0,他引:1
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Saito H Dubsky P Dantin C Finn OJ Banchereau J Palucka AK 《Breast cancer research : BCR》2006,8(6):R65-9
Introduction
The ability of dendritic cells (DCs) to take up whole tumor cells and process their antigens for presentation to T cells ('cross-priming') is an important mechanism for induction of tumor specific immunity.Methods
In vitro generated DCs were loaded with killed allogeneic breast cancer cells and offered to autologous naïve CD8+ T cells in 2-week and/or 3-week cultures. CD8+ T cell differentiation was measured by their capacity to secrete effector cytokines (interferon-γ) and kill breast cancer cells. Specificity was measured using peptides derived from defined breast cancer antigens.Results
We found that DCs loaded with killed breast cancer cells can prime naïve CD8+ T cells to differentiate into effector cytotoxic T lymphocytes (CTLs). Importantly, these CTLs primed by DCs loaded with killed HLA-A*0201- breast cancer cells can kill HLA-A*0201+ breast cancer cells. Among the tumor specific CTLs, we found that CTLs specific for HLA-A2 restricted peptides derived from three well known shared breast tumor antigens, namely cyclin B1, MUC-1 and survivin.Conclusion
This ability of DCs loaded with killed allogeneic breast cancer cells to elicit multiantigen specific immunity supports their use as vaccines in patients with breast cancer. 相似文献11.
Hong Wu Ruhui Li XiaoDong Hang Ming Yan Feng Niu Lidi Liu Wei Liu Song Zhao Shaokun Zhang 《JOURNAL OF BREAST CANCER》2011,14(3):175-180
Purpose
To investigate the distribution of CD44+/CD24- cells in breast cancers in relation to tumor size before and after the administration of neoadjuvant chemotherapy.Methods
CD44+/CD24- tumor cells obtained from breast cancer specimens were characterized in vivo and in vitro using tumor formation assays and mammosphere generation assays, respectively. The distribution of CD44+/CD24- tumor cells in 78 breast cancer specimens following administration of neoadjuvant chemotherapy was also evaluated using immunofluorescence assays, and this distribution was compared with the extent of tumor invasion predicted by Response Evaluation Criteria in Solid Tumours (RECIST).Results
In 27/78 cases, complete remission (CR) was identified using RECIST. However, 18 of these CR cases were associated with a scattered distribution of tumor stem cells in the outline of the original tumor prior to neoadjuvant chemotherapy. After neoadjuvant chemotherapy, 24 cases involved cancer cells that were confined to the tumor outline, and 21 cases had tumor cells or tumor stem cells overlapping the tumor outline. In addition, there were 6 patients who were insensitive to chemotherapy, and in these cases, both cancer cells and stem cells were detected outside the contours of the tumor volume imaged prior to chemotherapy.Conclusion
CD44+/CD24- tumor cells may be an additional parameter to evaluate when determining the extent of breast cancer invasion. 相似文献12.
Kannan Krishnamurthy Guanghu Wang Dmitriy Rokhfeld Erhard Bieberich 《Breast cancer research : BCR》2008,10(6):1-16
Introduction
At physiologic concentration in serum, the bile acid sodium deoxycholate (DC) induces survival and migration of breast cancer cells. Here we provide evidence of a novel mechanism by which DC reduces apoptosis that is induced by the sphingolipid ceramide in breast cancer cells.Methods
Murine mammacarcinoma 4T1 cells were used in vitro to determine apoptosis and alteration of sphingolipid metabolism by DC, and in vivo to quantify the effect of DC on metastasis.Results
We found that DC increased the number of intestinal metastases generated from 4T1 cell tumors grafted into the fat pad. The metastatic nodes contained slowly dividing cancer cells in immediate vicinity of newly formed blood vessels. These cells were positive for CD44, a marker that has been suggested to be expressed on breast cancer stem cells. In culture, a subpopulation (3 ± 1%) of slowly dividing, CD44+ cells gave rise to rapidly dividing, CD44- cells. DC promoted survival of CD44+ cells, which was concurrent with reduced levels of activated caspase 3 and ceramide, a sphingolipid inducing apoptosis in 4T1 cells. Z-guggulsterone, an antagonist of the farnesoid-X-receptor, obliterated this anti-apoptotic effect, indicating that DC increased cell survival via farnesoid-X-receptor. DC also increased the gene expression of the vascular endothelial growth factor receptor 2 (Flk-1), suggesting that DC enhanced the initial growth of secondary tumors adjacent to blood vessels. The Flk-1 antagonist SU5416 obliterated the reduction of ceramide and apoptosis by DC, indicating that enhanced cell survival is due to Flk-1-induced reduction in ceramide.Conclusions
Our findings show, for the first time, that DC is a natural tumor promoter by elevating Flk-1 and decreasing ceramide-mediated apoptosis of breast cancer progenitor cells. Reducing the level or effect of serum DC and elevating ceramide in breast cancer progenitor cells by treatment with Z-guggulsterone and/or vascular endothelial growth factor receptor 2/Flk-1 antagonists may thus be a promising strategy to reduce breast cancer metastasis. 相似文献13.
Maria Ryssdal Kraby Marit Valla Signe Opdahl Olav Anton Haugen Joanna Ewa Sawicka Monica Jernberg Engstrøm Anna Mary Bofin 《Breast cancer research and treatment》2018,171(2):283-293
Introduction
We hypothesized that breast tissue not involved by tumor in inflammatory breast cancer (IBC) patients contains intrinsic differences, including increased mammary stem cells and macrophage infiltration, which may promote the IBC phenotype.Materials and methods
Normal breast parenchyma?≥?5 cm away from primary tumors was obtained from mastectomy specimens. This included an initial cohort of 8 IBC patients and 60 non-IBC patients followed by a validation cohort of 19 IBC patients and 25 non-IBC patients. Samples were immunostained for either CD44+CD49f+CD133/2+ mammary stem cell markers or the CD68 macrophage marker and correlated with IBC status. Quantitation of positive cells was determined using inForm software from PerkinElmer. We also examined the association between IBC status and previously published tumorigenic stem cell and IBC tumor signatures in the validation cohort samples.Results
8 of 8 IBC samples expressed isolated CD44+CD49f+CD133/2+ stem cell marked cells in the initial cohort as opposed to 0/60 non-IBC samples (p?=?0.001). Similarly, the median number of CD44+CD49f+CD133/2+ cells was significantly higher in the IBC validation cohort as opposed to the non-IBC validation cohort (25.7 vs. 14.2, p?=?0.007). 7 of 8 IBC samples expressed CD68?+?histologically confirmed macrophages in initial cohort as opposed to 12/48 non-IBC samples (p?=?0.001). In the validation cohort, the median number of CD68?+?cells in IBC was 3.7 versus 1.0 in the non-IBC cohort (p?=?0.06). IBC normal tissue was positively associated with a tumorigenic stem cell signature (p?=?0.02) and with a 79-gene IBC signature (p?<?0.001).Conclusions
Normal tissue from IBC patients is enriched for both mammary stem cells and macrophages and has higher association with both a tumorigenic stem cell signature and IBC-specific tumor signature. Collectively, these data suggest that IBC normal tissue differs from non-IBC tissue. Whether these changes occur before the tumor develops or is induced by tumor warrants further investigation.14.
Victor P Andrade Irina Ostrovnaya Venkatraman E Seshan Mary Morrogh Dilip Giri Narciso Olvera Marina De Brot Monica Morrow Colin B Begg Tari A King 《Breast cancer research : BCR》2012,14(4):1-14
Introduction
Mammary-specific overexpression of Six1 in mice induces tumors that resemble human breast cancer, some having undergone epithelial to mesenchymal transition (EMT) and exhibiting stem/progenitor cell features. Six1 overexpression in human breast cancer cells promotes EMT and metastatic dissemination. We hypothesized that Six1 plays a role in the tumor initiating cell (TIC) population specifically in certain subtypes of breast cancer, and that by understanding its mechanism of action, we could potentially develop new means to target TICs.Methods
We examined gene expression datasets to determine the breast cancer subtypes with Six1 overexpression, and then examined its expression in the CD24low/CD44+ putative TIC population in human luminal breast cancers xenografted through mice and in luminal breast cancer cell lines. Six1 overexpression, or knockdown, was performed in different systems to examine how Six1 levels affect TIC characteristics, using gene expression and flow cytometric analysis, tumorsphere assays, and in vivo TIC assays in immunocompromised and immune-competent mice. We examined the molecular pathways by which Six1 influences TICs using genetic/inhibitor approaches in vitro and in vivo. Finally, we examined the expression of Six1 and phosphorylated extracellular signal-regulated kinase (p-ERK) in human breast cancers.Results
High levels of Six1 are associated with adverse outcomes in luminal breast cancers, particularly the luminal B subtype. Six1 levels are enriched in the CD24low/CD44+ TIC population in human luminal breast cancers xenografted through mice, and in tumorsphere cultures in MCF7 and T47D luminal breast cancer cells. When overexpressed in MCF7 cells, Six1expands the TIC population through activation of transforming growth factor-beta (TGF-β) and mitogen activated protein kinase (MEK)/ERK signaling. Inhibition of ERK signaling in MCF7-Six1 cells with MEK1/2 inhibitors, U0126 and AZD6244, restores the TIC population of luminal breast cancer cells back to that observed in control cells. Administration of AZD6244 dramatically inhibits tumor formation efficiency and metastasis in cells that express high levels of Six1 ectopically or endogenously. Finally, we demonstrate that Six1 significantly correlates with phosphorylated ERK in human breast cancers.Conclusions
Six1 plays an important role in the TIC population in luminal breast cancers and induces a TIC phenotype by enhancing both TGF-β and ERK signaling. MEK1/2 kinase inhibitors are potential candidates for targeting TICs in breast tumors. 相似文献15.
James W. Antoon Jiawang Liu Adharsh P. Ponnapakkam Matthew M. Gestaut Maryam Foroozesh Barbara S. Beckman 《Cancer chemotherapy and pharmacology》2010,65(6):1191-1195
Purpose
Resistance to endocrine and chemotherapies remains the primary cause of breast cancer treatment failure. We have synthesized four novel d-erythro N-octanoyl sphingosine analogs and catalogued their activity in drug-sensitive (MCF-7), endocrine-resistant (MDA-MB-231) and chemoresistant (MCF-7TN-R) breast cancer cells.Methods
3-(4,5-Dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine cell viability; colony assay was performed to determine effects on clonogenic survival and 1H NMR, 13C NMR, HPLC spectra and elemental analytical data analyses were used to determine analog identity and purity.Results
All four analogs inhibited both viability and clonogenic survival, with analog C exhibiting a log-fold improvement in anti-survival activity compared to the parent compound.Conclusion
With resistance to current breast cancer chemotherapies on the rise, the development of novel therapeutic targets is of growing importance. Our results show that lipid analogs have therapeutic potential in treating chemo- and endocrine-resistant breast cancer. 相似文献16.
Introduction
Exogenous prolactin is mitogenic and antiapoptotic in breast cancer cells, and overexpression of autocrine prolactin cDNA in breast cancer cell lines has been shown to stimulate their growth and to protect against chemotherapy-induced apoptosis. We examined the effects of the 'pure' prolactin receptor antagonist Δ1–9-G129R-hPrl (Δ1–9) on the breast cancer cell number and clonogenicity, alone and in combination with chemotherapy.Methods
The effects of doxorubicin, paclitaxel and Δ1–9 on the growth of breast cancer cell lines (MCF-7, T47D, MDA-MB-453, MDA-MB-468 and SK-BR-3) in monolayer culture were assessed by the sulphorhodamine B assay. Effects on clonogenicity were assessed by soft agar assay for the cell lines and by the mammosphere assay for disaggregated primary ductal carcinoma in situ samples. Dual-fluorescence immunocytochemistry was used to identify subpopulations of cells expressing the prolactin receptor and autocrine prolactin.Results
Δ1–9 as a single agent had no effect on the cell number in monolayer culture, but potentiated the cytotoxic effects of doxorubicin and paclitaxel. Doxorubicin accordingly induced expression of prolactin mRNA and protein in all five breast cancer cell lines tested. Δ1–9 alone inhibited the clonogenicity in soft agar of cell lines by ~90% and the mammosphere forming efficiency of six disaggregated primary ductal carcinoma in situ samples by a median of 56% (range 32% to 88%). Subpopulations of cells could be identified in the cell lines based on the prolactin receptor and prolactin expression.Conclusion
Autocrine prolactin appears to act as an inducible survival factor in a clonogenic subpopulation of breast cancer cells. The rational combination of cytotoxics and Δ1–9 may therefore improve outcomes in breast cancer therapy by targeting this cell population. 相似文献17.
Jonas Wolf Dyah Laksmi Dewi Johannes Fredebohm Karin Müller-Decker Christa Flechtenmacher J?rg D Hoheisel Michael Boettcher 《Breast cancer research : BCR》2013,15(6):R109
Introduction
Breast cancer stem cells are suspected to be responsible for tumour recurrence, metastasis formation as well as chemoresistance. Consequently, great efforts have been made to understand the molecular mechanisms underlying cancer stem cell maintenance. In order to study these rare cells in-vitro, they are typically enriched via mammosphere culture. Here we developed a mammosphere-based negative selection shRNAi screening system suitable to analyse the involvement of thousands of genes in the survival of cells with cancer stem cell properties.Methods
We describe a sub-population expressing the stem-like marker CD44+/CD24-/low in SUM149 that were enriched in mammospheres. To identify genes functionally involved in the maintenance of the sub-population with cancer stem cell properties, we targeted over 5000 genes by RNAi and tested their ability to grow as mammospheres. The identified candidate ATG4A was validated in mammosphere and soft agar colony formation assays. Further, we evaluated the influence of ATG4A expression on the sub-population expressing the stem-like marker CD44+/CD24low. Next, the tumorigenic potential of SUM149 after up- or down-regulation of ATG4A was examined by xenograft experiments.Results
Using this method, Jak-STAT as well as cytokine signalling were identified to be involved in mammosphere formation. Furthermore, the autophagy regulator ATG4A was found to be essential for the maintenance of a sub-population with cancer stem cell properties and to regulate breast cancer cell tumourigenicity in vivo.Conclusion
In summary, we present a high-throughput screening system to identify genes involved in cancer stem cell maintenance and demonstrate its utility by means of ATG4A. 相似文献18.
Hongjian Yang Yue Lu Yabing Zheng Xingfei Yu Xianghou Xia Xiangming He Weiliang Feng Lei Xing Zhiqiang Ling 《Cancer chemotherapy and pharmacology》2014,73(3):569-576
Purpose
Breast cancer is the cause for highest number of cancer-related death among women worldwide. This study was focused on investigating the role of zinc-finger protein X-linked (ZFX) in human breast cancer.Methods
Expression levels of ZFX were analyzed in 99 patients and four breast cancer cell lines. Lentivirus-mediated RNA interference was applied to silence ZFX expression, and the effects of ZFX knockdown on the growth of breast cancer cells were investigated.Results
The immunohistochemical expression of ZFX was higher in more advanced tumor tissues. ZFX was also overexpressed in multiple breast cancer cell lines. Knockdown of ZFX inhibited cell proliferation and colony formation of MCF-7 and MDA-MB-231 cells. Moreover, ZFX silencing resulted in cell cycle arrest at G0/G1 phase. Depletion of ZFX decreased the phosphorylation level of AKT and increased the phosphorylation level of ERK2 and the expression of cyclin D1, which is involved in cell survival and cell cycle regulation.Conclusions
These findings suggest that ZFX plays an important role in breast cancer development and could be a potential therapeutic target for breast cancer. 相似文献19.
Mohammad Kazzem Gheybi Shokrollah Farrokhi Mohammad Reza Ravanbod Afshin Ostovar Valiollah Mehrzad Pardis Nematollahi 《Breast cancer (Tokyo, Japan)》2017,24(6):756-764
Background
T regulatory cells (Tregs) are known to negatively control immune response. The frequency of these cells was inversely correlated with clinical outcomes of breast cancer. CD19+CD24hiCD38hi cells also play a critical role in inflammation and autoimmune disease. However, their function in tumor immune response is less studied. In this study we aimed to determine the role of CD19+CD24hiCD38hi cells and some other clinicopathological variables in increasing the proportion of Tregs in breast cancer patients.Methods
We selected 47 patients with invasive ductal breast carcinoma and 50 healthy controls and obtained their blood samples.Results
The proportion of circulating CD4+CD25+Foxp3+ Tregs and CD19+CD24hiCD38hi cells was significantly increased in breast cancer patients. We also found that increased proportion of Tregs in breast cancer is correlated with HER2 amplification, advanced clinical stages, serum TGF-β1 and increased CD19+CD24hiCD38hi cells in the peripheral blood.Conclusion
Altogether, our data suggest that as much as Tregs, CD19+CD24hiCD38hi B cells could also have a part in the suppression of immune response in breast cancer.20.