Tamoxifen (Nolvadex) is one of the most widely used and effective therapeutic agent for breast cancer. It benefits nearly 75% of patients with ER-positive breast cancer that receive this drug. Its effectiveness is mainly attributed to its capacity to function as an estrogen receptor (ER) antagonist, blocking estrogen binding sites on the receptor, and inhibiting the proliferative action of the receptor-hormone complex. Although, tamoxifen can induce apoptosis in breast cancer cells via upregulation of pro-apoptotic factors, it can also promote uterine hyperplasia in some women. Thus, tamoxifen as a multi-functional drug could have different effects on cells based on the utilization of effective concentrations or availability of specific co-factors. Evidence that tamoxifen functions as a GPR30 (G-Protein Coupled Receptor 30) agonist activating adenylyl cyclase and EGFR (Epidermal Growth Factor Receptor) intracellular signaling networks, provides yet another means of explaining the multi-functionality of tamoxifen. Here ordinary differential equation (ODE) modeling, RNA sequencing and real time qPCR analysis were utilized to establish the necessary data for gene network mapping of tamoxifen-stimulated MCF-7 cells, which express the endogenous ER and GPR30. The gene set enrichment analysis and pathway analysis approaches were used to categorize transcriptionally upregulated genes in biological processes. Of the 2,713 genes that were significantly upregulated following a 48 h incubation with 250 µM tamoxifen, most were categorized as either growth-related or pro-apoptotic intermediates that fit into the Tp53 and/or MAPK signaling pathways. Collectively, our results display that the effects of tamoxifen on the breast cancer MCF-7 cell line are mediated by the activation of important signaling pathways including Tp53 and MAPKs to induce apoptosis. Overall design: Gene expression analysis between tamoxifen-treated MCF-7 cells and untreated MCF-7 cells.
Tamoxifen-Induced Apoptosis of MCF-7 Cells via GPR30/PI3K/MAPKs Interactions: Verification by ODE Modeling and RNA Sequencing.
Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Genome-wide profiling of AP-1-regulated transcription provides insights into the invasiveness of triple-negative breast cancer.
Specimen part, Cell line
View SamplesTriple negative breast cancer (TNBC) is an aggressive clinical phenotype, and accounts for 15% to 20% of all breast cancers. The molecular determinants of malignant cell behaviors in TNBC remain largely unknown. We find that the AP-1 transcription factor component, Fra-1, is overexpressed in basal-like breast tumors, and its expression level has high prognostic significance. Depletion of Fra-1 or its heterodimeric partner c-Jun inhibits the proliferative and invasive phenotypes in TNBC cells. To gain insights into the transcriptional regulatory networks of AP-1 in TNBC cells, we combine genome-wide ChIP-seq with loss-of-function transcriptome analyses. We observe dysregulation of direct targets of the Fra-1/c-Jun heterodimer involved in cell proliferation, cell adhesion, and cell-cell contact. Intriguingly, we find that AP-1 mediates downregulation of E-cadherin through direct transcriptional induction of ZEB2. This work sheds light on the mechanisms and pathways by which TNBC acquires invasiveness and proliferative propensity.
Genome-wide profiling of AP-1-regulated transcription provides insights into the invasiveness of triple-negative breast cancer.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Prospective identification of resistance mechanisms to HSP90 inhibition in KRAS mutant cancer cells.
Cell line
View SamplesInhibition of the HSP90 chaperone results in depletion of many signaling proteins that drive tumorigenesis, such as downstream effectors of KRAS, the most commonly mutated human oncogene. As a consequence, several small-molecule HSP90 inhibitors are being evaluated in clinical trials as anticancer agents. To prospectively identify mechanisms through which HSP90-dependent cancer cells evade pharmacologic HSP90 blockade, we generated multiple mutant KRAS-driven cancer cell lines with acquired resistance to the purine-scaffold HSP90 inhibitor PU-H71. All cell lines retained dependence on HSP90 function, as evidenced by sensitivity to short hairpin RNA-mediated suppression of HSP90AA1 or HSP90AB1 (also called HSP90 and HSP90, respectively), and exhibited two types of genomic alterations that interfere with the effects of PU-H71 on cell viability and proliferation: (i) a Y142N missense mutation in the ATP-binding domain of HSP90 that co-occurred with amplification of the HSP90AA1 locus, (ii) genomic amplification and overexpression of the ABCB1 gene encoding the MDR1 drug efflux pump. In support of a functional role for these alterations, exogenous expression of HSP90 Y142N conferred PU-H71 resistance to HSP90-dependent cells, and pharmacologic MDR1 inhibition with tariquidar or lowering ABCB1 expression restored sensitivity to PU-H71 in ABCB1-amplified cells. Finally, comparison with structurally distinct HSP90 inhibitors currently in clinical development revealed that PU-H71 resistance could be overcome, in part, by ganetespib (also known as STA9090) but not tanespimycin (also known as 17-AAG). Together, these data identify potential mechanisms of acquired resistance to small molecules targeting HSP90 that may warrant proactive screening for additional HSP90 inhibitors or rational combination therapies.
Prospective identification of resistance mechanisms to HSP90 inhibition in KRAS mutant cancer cells.
Cell line
View SamplesAnti-PDGF agents are routinely used as a key component in front-line therapy for the treatment of various cancers. However, molecular mechanisms underlying their impact on vascular remodeling in relation to the dose issue remain poorly understood. Here we show that in high PDGF-BB-producing tumors, anti-PDGF drugs significantly inhibited tumor growth and metastasis by preventing pericyte (PC) loss and vascular permeability. Surprisingly, the same anti-PDGF-BB drugs promoted tumor cell dissemination and metastasis in PDGF-BB-low-producing or negative tumors by ablating PCs from tumor vessels. At the molecular level, we show that the PDGFR- signaling pathway in PCs mediated the opposing effects and persistent exposure of PCs to PDGF-BB led to marked downregulation of PDGFR-. Inactivation of the PDGFR- signaling system led to decreased levels of integrin 11, resulted in impaired adhesion of PCs to collagen I, IV and laminin, two principal extracellular matrix components in blood vessels for interaction with these integrins. Our data suggest that tumor PDGF-BB levels may serve as an important biomarker for selection of tumor-bearing hosts for beneficial therapy and unsupervised practice of this group of drugs could potentially promote tumor invasion and metastasis.
Tumour PDGF-BB expression levels determine dual effects of anti-PDGF drugs on vascular remodelling and metastasis.
Specimen part, Treatment
View SamplesGene expression in NPM1 wildtype and mutated AML patients with high or low hsa_circ_0075001 expression
Circular RNAs of the nucleophosmin (NPM1) gene in acute myeloid leukemia.
Specimen part, Disease, Disease stage
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The clathrin-binding domain of CALM and the OM-LZ domain of AF10 are sufficient to induce acute myeloid leukemia in mice.
Specimen part
View SamplesThe t(10;11) p (13;q14) translocation, giving rise to CALM-AF10, is a recurring chromosomal translocation observed in several types of acute leukemias as well as in lymphoma. We have previously demonstrated that the expression of the human CALM/AF10 fusion gene in murine bone marrow stem and progenitor cells results in an aggressive acute myeloid leukemia in vivo. In this study, we have screened the various domains essential for CALM-AF10 function and leukemogenicity. Our study identifies a mutant of CALM-AF10 that greatly enhances the clonogenic potential of hematopoietic progenitors while retaining key characteristics of disease induced by the full length CALM-AF10 fusion.
The clathrin-binding domain of CALM and the OM-LZ domain of AF10 are sufficient to induce acute myeloid leukemia in mice.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Integrative genomic and transcriptomic analysis identified candidate genes implicated in the pathogenesis of hepatosplenic T-cell lymphoma.
Age, Specimen part, Disease, Treatment
View Samples