Mechanotransduction regulates adipose estrogen output and its impact on tumor cell growth
ABSTRACT: Adipose stromal cells (ASCs) are the primary source of local estrogens in adipose tissue, aberrant production of which promotes estrogen receptor-positive (ER+) breast cancer. Here we show that extracellular matrix (ECM) rigidity and cell contractility are two opposing determinants for estrogen output of ASCs. Using synthetic ECMs and elastomeric micropost arrays with tunable rigidity, we find that increasing matrix compliance induces transcription of aromatase, a rate-limiting enzyme in estrogen biosynthesis. This mechanical cue is transduced sequentially by Discoidin Domain Receptor 1 (DDR1), c-Jun N-terminal kinase 1 (JNK1), and phosphorylated JunB, which binds to and activates two breast cancer-associated aromatase promoters. In contrast, elevated cell contractility due to actin stress fiber formation dampens aromatase transcription. Mechanically stimulated stromal estrogen production enhances estrogen-dependent transcription in ER+ tumor cells and promotes their growth. This novel mechanotransduction pathway underlies communications between ECM, stromal hormone output, and cancer cell growth within the same microenvironment. Total RNA was isolated from primary adipose stromal cells after 2d culture or 3d Collagen gel for 21 hours. Triplicates for each conditioned were analyzed
Project description:Adipose tissue-derived stromal stem cells (ASCs) represent a promising regenerative resource for soft tissue reconstruction. To understand the changes in cell function during the transition of ASCs into fully mature fat cells, we compared the transcriptome profiles of cultured undifferentiated human primary ASCs under conditions leading to acquisition of a mature adipocyte phenotype by microarray analysis. Microarray analysis was performed on total RNA extracted from separate ACS isolates of six human adult females before and after 7 days (7d: early stage) and 21 days (21d: late stage) of adipocyte differentiation in vitro.
Project description:Estrogen receptor positive (ER+) breast cancers that develop resistance to therapies that target the ER are the most common cause of breast cancer death. Beyond mutations in ER, which occur in 25-30% of patients treated with aromatase inhibitors (AIs), our understanding of clinical mechanisms of resistance to ER-directed therapies remains incomplete. We identified activating HER2 mutations in metastatic biopsies from eight patients with ER+ metastatic breast cancer who had developed resistance to ER-directed agents, including AIs, tamoxifen, and fulvestrant. Examination of treatment-naïve primary tumors in five patients revealed no evidence of pre-existing mutations in four of five patients, suggesting that these mutations were acquired under the selective pressure of ER-directed therapy. These mutations were mutually exclusive with ER mutations, suggesting a distinct mechanism of acquired resistance to ER-directed therapies. In vitro analysis confirmed that these mutations conferred estrogen independence. In addition, and in contrast to ER mutations, these mutations resulted in resistance to tamoxifen, fulvestrant, and the CDK4/6 inhibitor palbociclib. Resistance was overcome by combining ER-directed therapy with the irreversible HER2 kinase inhibitor neratinib, highlighting an effective treatment strategy in these patients. Overall design: Examination of the transcriptional output (mRNA) of the HER2 activating mutations compared with controls under various drugs. Specifically, we expressed the activating mutations S653C, L755S, V777L, and L869R in ER+/HER2- breast cancer cell line (T47D), and controls (GFP, wild-type HER2, kinase-dead HER2, and ESR1 Y537S). Cell were then treated with DMSO, 1μM fulvestrant, 1μM neratinib, 10μM palbociclib, 1μM fulvestrant + 1μM neratinib, or 1μM fulvestrant + 10μM palbociclib for 24 hours. All experimental conditions were done in 6 replicates, sequenced in 3 replicates
Project description:Acquired resistance to aromatase inhibitor (AI) therapy is a major clinical problem in the treatment of breast cancer. The detailed mechanisms of how tumour cells develop this resistance remain unclear. Here estrogen receptor ChIPseq analysis identifies adaptations of the ER in response to prolonged letrozole treatment. Overall design: Let-R cells were treated with either Androstenedione or vehicle and immunoprecipitated with anti-ER
Project description:Understanding the complex molecular mechanisms underlying resistance to endocrine therapy is a major challenge in the treatment of estrogen receptor-positive (ER+) breast cancers. We have previously demonstrated that glial cell line-derived neurotrophic factor (GDNF) signaling via the receptor tyrosine kinase RET promotes estrogen independent activation of ER. Here we have addressed the relevance of GDNF-RET signaling in response to aromatase inhibitor treatment and explored the efficacy of using RET inhibitors in breast cancer models of aromatase inhibitor response and resistance. A GDNF-response gene set, identified from gene expression profiling, was demonstrated to be an independent prognostic marker of poor patient outcome and, importantly, to be predictive of poor response to aromatase inhibitor treatment and development of resistance. The relevance of these findings was validated first by demonstrating an association of RET protein expression in an independent cohort of aromatase inhibitor resistant patient samples. Second, in in vitro models, GDNF-mediated RET signaling was demonstrated to enhance the survival of aromatase inhibitor resistant cells and to increase resistance in aromatase inhibitor sensitive cells. These effects could be reversed by targeting GDNF/RET signaling with the RET selective inhibitor NVP-BBT594 thus identifying GDNF-RET signaling as a potential therapeutic target, particularly in breast cancers resistant to aromatase inhibitors.<br>MCF7 cells were E2-deprived by culturing in phenol red-free RPMI 1640 supplemented with 10% DCC for 3 days and then serum-starved overnight in the presence or absence of fulvestrant (ICI182,780) (100 nM). The following day, cells were treated with GDNF (20 ng/ml) for 0, 4, 8, 24 and 48 hours in the presence or absence of fulvestrant (ICI182,780) (100 nM).
Project description:Cytoskeletal tension is an intracellular mechanism through which cells convert a mechanical signal into a biochemical response, including production of cytokines and activation of various signaling pathways. Adipose-derived stromal cells (ASCs) were allowed to spread into large cells by seeding them at a low-density (1,250 cells/cm2), which was observed to induce osteogenesis. Conversely, ASCs seeded at a high-density (25,000 cells/cm2) featured small cells that promoted adipogenesis. RhoA and actin filaments were altered by changes in cell size. Blocking actin polymerization by Cytochalasin D influenced cytoskeletal tension and differentiation of ASCs. To understand the potential regulatory mechanisms leading to actin cytoskeletal tension, cDNA microarray was performed on large and small ASCs. Connective tissue growth factor (CTGF) was identified as a major regulator of osteogenesis associated with RhoA mediated cytoskeletal tension. Subsequently, knock-down of CTGF by siRNA in ASCs inhibited this osteogenesis. Therefore, we conclude that cytoskeletal tension is important for CTGF-regulated ASC osteogenic differentiation. Computed
Project description:Estrogen receptor-α (ERα) is an important driver of breast cancer and is the target for hormonal therapies, anti-estrogens and drugs that limit estrogen biosynthesis (aromatase inhibitors). Mutations in the ESR1 gene identified in metastatic breast cancer provide a potential mechanism for acquired resistance to hormone therapies. We have used CRISPR-Cas9 mediated genome editing in the MCF-7 breast cancer cell line, generating MCF-7-Y537S. MCF-7-Y537S cells encode a wild-type (tyrosine 537) and a mutant (serine 537) allele. Growth of the line is estrogen-independent and expression of ERα target genes is elevated in the absence of estrogen. ER ChIP-seq was carried out to map global ERα binding sites in the presence and absence of estrogen. RNA-seq following estrogen treatment was used for gene expression analysis. We show that expression of ER target genes and ER recruitment to ER binding regions is similar in MCF-7 and MCF-7-Y537S cells, except that ER recruitment to DNA and expression of ER target genes is frequently elevated in the absence of estrogen Hormone depleted MCF-7 LUC /Y537S mutant cells were treated with estrogen (10nM) or ETOH as vehicle control for 45 mins. Erα Chip-seq was performed using Illumnia methodology
Project description:Cytoskeletal tension is an intracellular mechanism through which cells convert a mechanical signal into a biochemical response, including production of cytokines and activation of various signaling pathways. Adipose-derived stromal cells (ASCs) were allowed to spread into large cells by seeding them at a low-density (1,250 cells/cm2), which was observed to induce osteogenesis. Conversely, ASCs seeded at a high-density (25,000 cells/cm2) featured small cells that promoted adipogenesis. RhoA and actin filaments were altered by changes in cell size. Blocking actin polymerization by Cytochalasin D influenced cytoskeletal tension and differentiation of ASCs. To understand the potential regulatory mechanisms leading to actin cytoskeletal tension, cDNA microarray was performed on large and small ASCs. Connective tissue growth factor (CTGF) was identified as a major regulator of osteogenesis associated with RhoA mediated cytoskeletal tension. Subsequently, knock-down of CTGF by siRNA in ASCs inhibited this osteogenesis. Therefore, we conclude that cytoskeletal tension is important for CTGF-regulated ASC osteogenic differentiation. Overall design: Computed
Project description:Therapies targeting estrogenic stimulation in estrogen receptor positive (ER+) breast cancer (BC) reduce mortality, but resistance remains a major clinical problem. Molecular studies have shown few high frequency mutations to be associated with endocrine resistance. In contrast, expression profiling of primary ER+ BC samples has identified several promising signatures/networks for targeting. In this study, the cholesterol biosynthesis pathway was the common upregulated pathway in the ER+ LTED but not ER- LTED cell lines, suggesting a potential mechanism dependent on continued ER expression. Targeting the individual genes of the cholesterol biosynthesis pathway with siRNAs caused a 30-50% drop in proliferation. Further analysis showed increased expression of 25-hydroxycholesterol (HC) in the MCF7 LTED cells. Exogenous 25-HC or 27-HC increased ER mediated-transcription and expression of the endogenous estrogen-regulated gene TFF1 in ER+ LTED cells but not in the ER-negative LTED. Additionally, recruitment of the ER and CREB-binding protein (CBP) to the TFF1 promoter was increased upon treatment with 25-HC and 27-HC. In silico analysis of 704 primary ER+ BC patients treated with adjuvant tamoxifen showed increased expression of MSMO1 (p=0.047), EBP (p=0.043), SQLE (p=0.000009), and IDI1 (p=0.0005), enzymes required for cholesterol synthesis and increased in our in vitro models of endocrine resistance, to be associated with poor relapse-free survival. In contrast, no association was identified in over 700 patients with ER-negative BC. Taken together, these data provide support for the role of cholesterol biosynthesis enzymes and the cholesterol metabolites, 25-HC and 27-HC, in a novel mechanism of resistance to endocrine therapy in ER+ BC that has potential as a therapeutic target. Overall design: To identify common adaptive mechanisms associated with resistance to aromatase inhibitors (AI), we assessed changes in global gene expression during adaptation to long-term estrogen deprivation (LTED) in a panel of ER+ BC cell lines cultured in 2D on plastic (MCF7, T47D, HCC1428, SUM44 and ZR75.1) or 3D on collagen (MCF7) to model the stromal compartment. Furthermore, dimethyl labelling followed by LC-MS/MS was used to assess global changes in protein abundance. The role of target genes/proteins on proliferation, ER-mediated transcription and recruitment of ER to target gene promoters was analysed
Project description:To better understand the scale of gene expression changes that occur during the formation of mature adipocytes from preadipocytes, we compared and characterised the transcriptome profile of mesenchymal stromal cells derived from human adipose tissue, otherwise known as adipose-derived stromal cells (ASCs), undergoing adipocyte differentiation on day 1, 7, 14 and 21 (representing the early to late stage process of adipogenesis). Microarray technique was systematically employed to study gene expression in adipose-derived stromal cells during adipogenic differentiation over a 21 day period to identify genes that are important in driving adipogenesis in humans. We have undertaken an in-depth transcriptome analysis of adipogenesis in human adipose-derived stromal cells (ASCs) induced to differentiate into adipocytes in vitro. Genes were differentially expressed on days 1, 7, 14 and 21 post-induction and numbered 128, 218, 253 and 240 respectively. Up-regulated genes were associated with neural and blood vessel development, leukocyte migration, and tumor growth, invasion and metastasis. They also shared common pathways with certain obesity-related pathophysiological conditions. Down-regulated genes were associated with osteogenesis and the immune response. KLF15, LMO3, FOXO1 and ZBTB16 transcription factors were up-regulated throughout the differentiation process. CEBPA, PPARG, ZNF117, MLXIPL, MMP3 and RORB were up-regulated only on days 14 - 21, which coincides with the maturation of adipocytes and could possibly serve as candidates for controlling fat accumulation and the size of mature adipocytes. We identified genes that were up-regulated only on day 1 - 7 and day 14 - 21 that could serve as potential early and late-stage differentiation markers. This study reveals potential markers for the different stages in ASC adipogenic differentiation which could serve as good candidates to combat obesity and further link the biology of fat cell formation to the co-morbidities of obesity. Overall design: RNA was extracted from both adipogenic induced adipose-derived stromal cell cultures and their respective controls (non-induced) on day 1, 7, 14 and 21. The RNA were hybridized to Affymetrix HuGene 2.0 ST arrays
Project description:Estrogen deprivation using aromatase inhibitors is currently the standard of care for patients with estrogen-receptor (ER)-positive breast cancer. Unfortunately, prolonged estrogen deprivation leads to drug resistance (i.e. hormone-independent growth). We therefore used DNA microarray analysis to study the gene expression profiles of wild-type MCF-7 cells (which are sensitive to antihormone therapy) and long-term estrogen deprived MCF-7:5C and MCF-7:2A breast cancer cells (which are resistance to estrogen-deprivation; aromatase inhibitor resistant). Transcriptional profiling of wild-type MCF-7 cells and estrogen deprived MCF-7:5C and MCF-7:2A cells was performed using Affymetrix Human Genome U133 Plus 2.0 Array. Keywords: breast cancer cells, estrogen Overall design: We wanted to study the gene expression profiles of the different cell lines in their growth media without any drug treatment. Therefore, MCF-7, MCF-7:5C, and MCF-7:2A cells were grown in estrogen-free media (phenol red-free RPMI medium supplemented with 10% 4X dextran-coated charcoal-treated fetal bovine serum) until they were 70-80% confluent then RNA was extracted, labeled, and hybridized to the Affymetrix Human Genome U133 Plus 2.0 Arrays.