Combination of epigenetic, differentiation and DNA damaging agents induce tumor cell death and stem cell depletion in breast cancer
ABSTRACT: Gene expression profiles were performed on MDA-MB-231 TNBC cell line treated with entinostast, all-trans retinoic acid (ATRA), and doxorubicin as single, double, and triple combinations using Illumina. Treatment signatures were made from each drug treatment and integrated to find a comprehensive view of changes associated with the epigenetic, differentiation and chemotherapy combination
Project description:Glucocorticoids (GC) have been widely used as coadjuvants in the treatment of solid tumors, but GC treatment may be associated with poor pharmacotherapeutic response and/or prognosis. The genomic action of GC in these tumors is largely unknown. Here we find that dexamethasone (Dex, a synthetic GC) regulated genes in triple-negative breast cancer (TNBC) cells are associated with drug resistance. Importantly, these GC-regulated genes are aberrantly expressed in TNBC patients and associated with unfavorable clinical outcomes. Interestingly, in TNBC cells, Compound A (CpdA, a selective GR modulator) only regulates a small number of genes not involved in carcinogenesis and therapy resistance. Mechanistic studies using a ChIP-exo approach reveal that Dex- but not CpdA-liganded glucocorticoid receptor (GR) binds to a single glucocorticoid response element (GRE), which drives the expression of pro-tumorigenic genes. Our data suggest that development of safe coadjuvant therapy should consider the distinct genomic function between Dex- and CpdA-liganded GR. To study GR-regulated genes and define GRE in human genome, RNA-seq and GR ChIP-exo are performed in MDA-MB-231 cells before/after dex and CpdA stimulation. Each experiment includes two replicates.
Project description:Triple negative breast cancer (TNBC) is characterized by a poorly differentiated phenotype and limited treatment options. Aberrant epigenetics in this subtype represent a potential therapeutic opportunity, but a better understanding of the mechanisms contributing to the TNBC pathogenesis is required. The SIN3 molecular scaffold performs a critical role in multiple cellular processes, including epigenetic regulation, and has been identified as a potential therapeutic target. Using a competitive peptide corresponding to the SIN3 interaction domain of MAD (Tat-SID), we investigated the functional consequences of selectively blocking the paired amphipathic helix (PAH2) domain of SIN3. Here, we report the identification of the SID-containing adaptor PF1 as a factor required for maintenance of the TNBC stem cell phenotype and epithelial to mesenchymal transition (EMT). Tat-SID peptide blocked the interaction between SIN3A and PF1, leading to epigenetic modulation and transcriptional downregulation of TNBC stem cell and EMT markers. Importantly, Tat-SID treatment led to a reduction in primary tumor growth and disseminated metastatic disease in vivo. In support of these findings, knockdown of PF1 expression phenocopied treatment with Tat-SID both in vitro and in vivo. These results demonstrate a critical role for a complex containing SIN3A and PF1 in TNBC and provide a rational for its therapeutic targeting. Sub-confluent cultures of MDA-MB-231 cells were treated with 1µM Tat-SID peptide or 1µM Tat-Scr scrambled control peptide for 24hr.
Project description:Mutant p53 proteins, resulting form frequent TP53 tumor suppressor missense mutations, possess gain-of-function activities and are among the most widespread and robust oncoproteins in human tumors. They are potentially important but understudied therapeutic targets. No studies to date have distinguished common, therapeutically relevant mutant p53 gain-of-function effects, from effects specific to different mutant variants and cell backgrounds. Here we identify 26S proteasome machinery as the common downstream effector controlled by mutant p53s in Triple Negative Breast Cancer (TNBC - aggressive carcinomas with TP53 as the most frequently mutated locus) and conserved in other human cancers. We have identified this pathway using a combination of single-model, multi-method vertical analysis (whole cell proteome, RNA sequencing an ChIP sequencing) and multi-cell line, horizontal analysis of transcriptiomes. We found that different missense mutant p53s regardless of the cell background transcriptionaly activate whole 26S proteasome machinery. Proteasome activity is significantly increased in p53 mutant versus wild-type or knockdown/null status - in cellular and mouse models as well as in human breast tumors. Increased proteasome activity leads to inhibition of tumor suppressive pathways. The control of mutant p53 over proteasome transcription and activity results in the increased resistance to proteasome inhibitors. By combining the mutant p53 targeting agents and proteasome inhibitor we were able to overcome the “bounce-back” proteasome inhibitor resistance mechanism in mutant p53 bearing TNBC cells and xenografts in vivo.
Project description:Efforts to improve the clinical outcome of highly aggressive triplenegative breast cancer (TNBC) have been hindered by the lack of effective targeted therapies. Hence, it is important to identify the specific gene targets/pathways driving the invasive phenotype to develop more effective therapeutics. Here we show that UBASH3B (ubiquitin associated and SH3 domain containing B), a protein tyrosine phosphatase, is overexpressed in TNBC, where it supports malignant growth, invasion and metastasis in large through modulating EGFR. We also show that UBASH3B is a functional target of anti-invasive miR-200a that is downregulated in TNBC. Importantly, the oncogenic potential of UBASH3B is dependent on its tyrosine phosphatase activity, which targets CBL ubiquitin ligase for dephosphorylation and inactivation, leading to EGFR upregulation. Thus, UBASH3B may function as a crucial node in bridging multiple invasion-promoting pathways, thus providing a potential new therapeutic target for TNBC. Breast cancer tissues and breast cancer cell lines
Project description:Tumor infiltrating lymphocytes (TILs) play a critical role in modulating the immunoediting features in certain malignancies like triple negative breast cancer (TNBC). Nevertheless, much is still unknown concerning the specific responses of tumors when challenged by lymphocyte infiltration. Based on this void, we conducted a immuno-phenotype comparison using mRNA sequencing between the TNBC cell line MDA-MB-231 and the luminal breast cancer cell line MCF7 after both were co-cultured with activated human T-cells. We found that, though the cytokine-induced immune signature of the two cell lines was similar, MDA-MD-231 cells were able to transcribe IDO1 at a significantly higher level than MCF7 cells. Though no differences occurred in upstream JAK/STAT1 signaling or IDO1 mRNA stability between the two cell lines, stimulation with IFNγ was able to differentially induce IDO protein expression and enzymatic activity in ER- cell lines compared to ER+ cell lines. Further experiments show that 5-aza-deoxycytidine treatment was able to reverse suppression of IDO1 expression in MCF7 cells, suggesting DNA methylation as a potential determinant in IDO1 induction. By analyzing TCGA breast cancer datasets, we discovered subtype-specific mRNA and promoter methylation differences in IDO1, with TNBC/basal subtypes exhibiting lower methylation/higher expression and ER+/luminal subtypes exhibiting higher methylation/lower expression. We confirmed this trend of IDO1 methylation by bisulfite pyrosequencing breast cancer cell lines and an independent cohort of primary breast tumors. Taken together, these findings suggest that IDO1 methylation regulates anti-immune responses in breast cancer subtypes and could be used as a predictive biomarker for IDO inhibitor-based immunotherapy. To determine the immunomodulatory effects of cytokines secreted by activated human T-cells on breast cancer cells, we performed RNAseq analysis in MCF7 and MDA-MB-231 cells, after co-culturing them with normal PBMCs activated with anti-CD3/CD28 antibodies in a contact-independent manner. MDA-MB-231 or MCF7 cells were co-cultured with PBMCs alone or the conditioned-media or a combination of both for 24 hrs, and then total RNA was harvest for RNA-seq analysis.
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: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:Breast cancer (BC) is the most common cancer in women worldwide, and is classified in multiple subtypes, including the so called triple-negative BC (TNBC). This is characterized by lack of estrogen receptor alpha (ERα), progesterone receptor (PR) and epidermal growth factor receptor 2 (HER2/neu), that represent common targets for BC treatment. Their absence limits the number of therapies that may be applied for TNBC treatment, suggesting the need to identify novel therapeutic targets against this disease. Several studies reported that the beta ER subtype (ERβ) is expressed in a sizeable fraction of TNBCs where its presence correlates with improved patient outcome. We evaluated ERβ expression in TNBC tissues by immunohistochemistry using two validated antibodies, demonstrating presence of this protein in 28% of samples. To investigate, in this context, the role of this estrogen receptor in TNBC biology, ERβ-expressing cell lines, representing different TNBC subtypes, were generated. Cellular and functional assays confirmed the antiproliferative activity of ERβ in TNBCs. Interaction proteomics revealed in BC nuclei the presence of several protein complexes associated with this receptor involved in chromatin remodeling, miRNA maturation and mRNA transcription. Transcriptome analyses pointed out tumor subtype-specific signaling pathways deregulation. Interestingly, among these the cholesterol biosynthesis pathway was commonly downregulated in all cell lines tested. Global analyses of ERβ binding to the genome showed its recruitment to regulatory sites of Sterol Regulatory Element-Binding Protein 1 (SREBP1), indicating a direct regulation of this pathway by the receptor. These findings suggest that drugs targeting components of cholesterol biosynthesis pathway may be new potential therapeutic options for TNBC treatment.
Project description:We performed whole transcriptome sequencing of human monocytes that were co-cultured with estrogen receptor positive (ER+) or triple-negative (TNBC) breast cancer cell lines and studied the biological responses related to the differential gene activation in both cell types to understand how different cancer cells educate host cells to support tumor growth To characterize the differences in macrophage activation under the influence of either ER+ or TNBC breast cancer cells, we cultured freshly isolated human peripheral monocytes with two breast cancer cell lines (T47D, ER+ and MDA-MB-231, TNBC) in an in vitro transwell co-culture assay. The transwell setting allowed us to investigate the effect of soluble mediators on macrophage activation since direct cell contact of these cells was inhibited by a (PET) membrane (pore size 0.4 μm).
Project description:Triple-negative breast cancer (TNBC) is defined by the absence of estrogen and progesterone receptors and human epidermal growth factor receptor 2, and is the most lethal and aggressive subtype of breast cancer. However, the genes which relate to promote tumor aggressiveness in TNBC remain unclear. In order to investigate specific genes and pathways involved in TNBC tumorigenesis, we compared genes differentially expressed between 3D cultures (3DC) or tumor xenograft models and control two-dimensional cultures (2DC). Total RNA was prepared from the TNBC cells under the condition of 2DC, 3DC and tumor xenograft models, and applied to Affymetrix Human Genome U133 Plus 2.0 Array.