Oct4 affects E-cadherin expression via regulating Rnd1 associated cytoskeleton rearrangement in breast cancer cells
ABSTRACT: Oct4, a key transcription factor for maintaining the pluripotency and self-renewal of stem cells has been reported previously. It also plays an important role in tumor proliferation and apoptosis, but the role of Oct4 been in tumor metastasis is still not very clear. Here, we found that ectopic expression of Oct4 in breast cancer cells can inhibit their migration and invasion. Detailed examinations revealed that Oct4 up-regulates expression of E-cadherin, indicative of its inhibitory role in epithelial-mesenchymal transition (EMT). RNA-sequence assay showed that Oct4 down-regulates expression of Rnd1. As an atypical Rho protein, Rnd1 can affect cytoskeleton rearrangement and regulate cadherin-based cell-cell adhesion by antagonizing the typical Rho protein, RhoA. Ectopic expression of Rnd1 in MDA-MB-231 cells changes cell morphology which influences cell adhesion and increases migration. It is reported that EMT is accompanied by cytoskeleton remodeling, we hypothesized that Rnd1 may play a role in regulating EMT. Over-expression of Rnd1 can partly rescue the inhibitory effects induced by Oct4, not only migration and invasion, but also in E-cadherin level and cellular morphology. Furthermore, silencing of Rnd1 can up-regulate the expression of E-cadherin in MDA-MB-231 cells. These results present evidence that ectopic expression of Oct4 increases E-cadherin and inhibits metastasis, effects which may be related to Rnd1 associated cell-cell adhesion in breast cancer cells. Examination of mRNA profiles in MDA-MB-231 cells with OCT4 overexpressing
Project description:RNA was isolated from ectopically sFRP1-expressing MDA-MB-231 cells and control MDA-MB-231 cells and as well from tumor lysates arising from these cells as nude mouse xenograft. Gene expression profiles for these samples were investigated using Affymetrix arrays. Experiment Overall Design: MDA-MB-231 human breast cancer cells were stably transfected with human sFRP1 encoding vector or empty vector as control. After the selection with antibiotics, three clones of MDA-MB-231/sFRP1 and three clones of MDA-MB-231/control were selected. These six clones were cultured individually in DMEM 10% FCS with 1mg/ml G-418. When cells reached 70-80% confluence, RNA was isolated from the cells. In parallel, the three clones of MDA-MB-231/sFRP1 and the three clones of MDA-MB-231/control were pooled respectively. One million of cells from each pool were suspended in 100ul PBS and injected to fat pads of female balb/c nude mice (6 mice were injected with MDA-MB-231/sFRP1 and 5 mice were injected with MDA-MB-231/control) to do a xenograft experiment. A few - several weeks after, mice were sacrificed when tumor reached a certain size, tumors were taken and RNA was isolated using trizol reagent.
Project description:Acquired drug resistance represents a major challenge in chemo-therapy treatment for various types of cancers. We have found that the retinoid X receptor–selective agonist bexarotene (LGD1069, Targretin) was efficacious in treating chemo-resistant cancer cells. The goal of this microarray study was to understand the mechanism of bexarotene’s role in overcoming acquired drug resistance using human breast cancer cells MDA-MB-231 as a model system and paclitaxel as model compound. After MDA-MB-231 cells were repeatedly treated with paclitaxel for 8 cycles with each cycle including a 3-day treatment with 30 nM paclitaxel and followed by a 7-day exposure to control medium, MDA cells resistant to paclitaxel were developed and their growth was no longer inhibited by paclitaxel treatment. Those MDA cells with acquired drug resistance, when treated with paclitaxel and bexarotene in combination, could regain their sensitivity and their growth were again inhibited. Therefore, RNA samples from parental MDA-MB-231 cells, paclitaxel-resistant MDA cells treated with vehicle, paclitaxel alone or in combination with bexarotene, were used for perform global gene expression profiling with Affymetrix HG-U133A gene chips. Keywords: Drug Treatment MDA-MB-231 cells were exposed to regimens on a 10-day cycle: a 3-day treatment with 30 nM paclitaxel and followed by a 7-day exposure to control medium. Paclitaxel resistant MDA-MB-231 cells (MDA-PR) were established within 8 cycles of such treatment (80 days). These MDA-PR cells were then treated with vehicle control, paclitaxel along, or the combination of 30 nM paclitaxel ( 3 days on and 7 days off) and 1 µM Targretin (10 days on) in a new 10-day cycle for 3 months. Thus, there are four treatment groups, parent MDA cells, MDA-PR, MDA-PR treated with paclitaxel, MDA-PR treated with paclitaxel and bexarotene, and each group had four biological replicates.
Project description:Identification of MUC4-associated expression of genes by comparing MUC4 knockdown (MDA-MB-231-shMUC4) and control (MDA-MB-231-SCR). Two-condition experiment, MUC4 knockdown cells vs. control. Biological replicates: 2 control, 2 sh-MUC4 transfected, independently grown and harvested. one replicate per array.
Project description:To further investigate the molecular mechanisms by which EVs mediated the abnormal localization of tight junction proteins and adherence junction protein, we performed miRNA microarray analysis of extracellular vesicles isolated from breast cancer cells. miRNA expression in extracellular vesicles was collected from MDA-MB-231-D3H1, MDA-MB-231-D3H2LN, BMD2a and BMD2b breast cancer cell lines.
Project description:Small-molecule Smac mimetics target inhibitor of apoptosis (IAP) proteins to induce TNFα-dependent apoptosis in cancer cells and several Smac mimetics have been advanced into clinical development as a new class of anticancer drugs. However, preclinical studies have shown that only a small subset of cancer cell lines are sensitive to Smac mimetics used as single agents and these cell lines are at risk of developing drug resistance to Smac mimetics. Thus, it is important to understand the molecular mechanisms underlying intrinsic and acquired resistance of cancer cells to Smac mimetics in order to develop effective therapeutic strategies to overcome or prevent Smac mimetic resistance. We established Smac mimetic resistant sublines derived from MDA-MB-231 breast cancer cells, which exhibit exquisite sensitivity to the Smac mimetic SM-164, and used microarrays to detail the global programme of gene expression underlying SM-164 resistance in MDA-MB-231 cells and identified differentially expressed genes in SM-164-resistant and -sensitive MDA-MB-231 cells. SCID mice with MDA-MB-231 xenograft tumors were treated with 5 mg/kg of SM-164 intravenously for 5 days/week for 2 weeks. SM-164-regressed MDA-MB-231 tumors regrew after treatment ended. Tumor cells from these regrown MDA-MB-231 tumors were isolated and total RNAs were prepared for microarray analysis.
Project description:Identifying the gene expression alterations that occur in both the tumor and stroma is essential to understanding tumor biology. We have developed a dual-species microarray analysis method that allows the dissection of both tumor and stromal gene expression profiles from xenograft models, based on limited interspecies cross-hybridization on Illumina gene expression beadchips. This methodology allows for simultaneous genome-wide analysis of gene expression profiles of both tumor cells and the associated stromal tissue. Data is provided regarding the crosshybridization of mouse liver RNA on human microarray, and MDA-MB-231 breast cancer cell line RNA on mouse microarray. Data is also provided for comparisons of MDA-MB-231 gene expression in vitro vs. in vivo, and mouse liver gene expression in control mice vs. stroma from MDA-MB-231 xenograft liver metastasis in tumor bearing mice A total of 18 samples were analyzed. Samples consist of 6 different types with each type in triplicate. Types are (1) MDA-MB-231 cell line grown in vitro and arrayed on mouse chips, (2) mouse liver from NOD/SCID mice arrayed on human chips, (3) MDA-MB-231 cell line grown in vitro arrayed on human chips, (4) MDA-MB-231 xenograft liver metastasis arrayed on human chips, (5) mouse liver from NOD/SCID mice arrayed on mouse chips, and (6) MDA-MB-231 xenograft liver metastasis arrayed on mouse chips. The overall design had three objectives: (1) to determine crosshybridizing probes based on sample types 1, 2, 3, and 5, (2) detect stromal and tumor expression using sample types 4 and 6, and (3) determine genes differentially expressed in tumor or metastasis compared to normal by comparing sample types 3 and 4 and comparing sample types 1 and 5.
Project description:Epithelial-to-mesenchymal transition (EMT) is a fundamental process in development and disease. If aberrantly activated it is a trigger for tumour progression and metastasis (Thiery et al 2009 Cell). It is now known that EMT activation is also associated with the maintenance of stem-cell properties (Mani et al. 2008 Cell). Since Zinc-finger enhancer binding transcription factor 1 (ZEB1) is a crucial EMT activator, we analyzed the changes in the gene expression profile that accompany shRNA mediated loss of ZEB1 in MDA MB 231 basal type breast cancer cells. MDA MB 231 is a cell line that exhibits mesenchymal characteristics, but reverts to an epithelial phenotype upon ZEB1 knock down (Spaderna et al. 2008 Cancer Research). MDA MB 231 cells were stably transfected with control (GFP) or ZEB1 shRNA. Upon puromycin selection, single cell clones were picked and characterized. Cells from two control versus two ZEB1 knockdown clones were harvested, total RNA was isolated and processed to hybridization.
Project description:MiR-544 was inhibited by either a miR-544 antagomir or compound 1 under hypoxic conditions in MDA-MB-231 cells MiRNA microarray was utilized to examine the specificity of 1 for miR-544. 3 MDA-MB-231 samples treated with a miR-544 antagomir or compound 1 were subjected to hypoxia for a period of 5 days. After 5 days, samples were pooled and subjected to miRNA microarray analysis.
Project description:In order to identify patterns of gene expression that are associated with the putative tumor suppressor gene ITIH5 mediated suppression of breast cancer metastatic growth, we performed a transcriptomic micro-array analysis of the MDA-MB-231 wildtype, three independent highly aggressive MDA-MB-231-mock clones and four independent weak aggressive MDA-MB-231-ITIH5 clones. Related methylation profiling data are found under accession <a href='../E-MTAB-5081/'>E-MTAB-5081</a>.
Project description:To investigate the mRNA expression after extracellular vesicles or miRNA treatement, global gene expression analysis was performed in endothelial cells after the transfection of N.C. or miR-181c and or after the addition of extracellular vesicles from cancer cells. mRNA expression in brain endothelial cells was collected from negative control or miR-181c treatment and or after the addition of extracellular vesicles from MDA-MB-231-D3H1, MDA-MB-231-D3H2LN, BMD2a and BMD2b breast cancer cell lines.