Acquired resistance to endocrine therapy occurs with high frequency in patients with luminal breast cancer (LBC). We report here the establishment of four patient-derived xenograft models of LBC with acquired resistance in vivo to tamoxifen and estrogen deprivation.
Acquired resistance to endocrine treatments is associated with tumor-specific molecular changes in patient-derived luminal breast cancer xenografts.
Specimen part
View SamplesOver the last decade, small noncoding RNA molecules such as microRNAs (miRNAs) have emerged as critical regulators in the expression and function of eukaryotic genomes. It has been suggested that viral infections and neurological disease outcome may also be shaped by the influence of small RNAs. This has prompted us to suggest that HIV infection alters the endogenous miRNA expression patterns, thereby contributing to neuronal deregulation and AIDS dementia. Therefore, using primary cultures and neuronal cell lines, we examined the impact of a viral protein (HIV-1 Tat) on the expression of miRNAs due to its characteristic features such as release from the infected cells and taken up by noninfected cells. Using microRNA array assay, we demonstrated that Tat deregulates the levels of several miRNAs. Interestingly, miR-34a was among the most highly induced miRNAs in Tat-treated neurons. Tat also decreases the levels of miR-34a target genes such as CREB protein as shown by real time PCR. The effect of Tat was neutralized in the presence of anti-miR-34a. Using in situ hybridization assay, we found that the levels of miR-34a increase in Tat transgenic mice when compared with the parental mice. Therefore, we conclude that deregulation of neuronal functions by HIV-1 Tat protein is miRNA-dependent.
HIV-1 Tat protein promotes neuronal dysfunction through disruption of microRNAs.
Specimen part, Cell line, Treatment
View SamplesOur previous studies have shown that C/EBP plays a critical role in human endometrial stromal decidualization. In order to identify the molecular pathways regulated by C/EBP during decidualization, we performed gene expression profiling using RNA isolated from normal and C/EBP-deficient human endometrial stromal cells. The microarray results revealed that several key regulators of stromal differentiation, such as BMP2, Wnt4, IL-11R and STAT3, operate downstream of C/EBP during decidualization. Further studies revealed that STAT3 is a direct target of C/EBP and plays an important role in cytokine signal during the decidualization process. Gene expression profiling, using STAT3-deficient HESCs, showed an extensive overlap of pathways downstream of STAT3 and C/EBP during stromal cell differentiation.
Regulation of human endometrial stromal proliferation and differentiation by C/EBPβ involves cyclin E-cdk2 and STAT3.
Specimen part
View SamplesStudies have shown that HIV-infected patients develop neurocognitive disorders characterized by neuronal dysfunction. The lack of productive infection of neurons by HIV suggests that viral and cellular proteins, with neurotoxic activities, released from HIV-1-infected target cells can cause this neuronal deregulation. The viral protein R (Vpr), a protein encoded by HIV-1, has been shown to alter the expression of various important cytokines and inflammatory proteins in infected and uninfected cells; however the mechanisms involved remain unclear. Using a human neuronal cell line, we found that Vpr can be taken up by neurons causing: (i) deregulation of calcium homeostasis, (ii) endoplasmic reticulum-calcium release, (iii) activation of the oxidative stress pathway, (iv) mitochondrial dysfunction and v- synaptic retraction. In search for the cellular factors involved, we performed microRNAs and gene array assays using human neurons (primary cultures or cell line, SH-SY5Y) that we treated with recombinant Vpr proteins. Interestingly, Vpr deregulates the levels of several microRNAs (e.g. miR-34a) and their target genes (e.g. CREB), which could lead to neuronal dysfunctions. Therefore, we conclude that Vpr plays a major role in neuronal dysfunction through deregulating microRNAs and their target genes, a phenomenon that could lead to the development of neurocognitive disorders.
Deregulation of microRNAs by HIV-1 Vpr protein leads to the development of neurocognitive disorders.
Specimen part, Cell line, Treatment
View SamplesAberrant splicing is a hallmark of leukemias with mutations in splicing factor (SF)-encoding genes. Here we investigated its prevalence in pediatric B-cell acute lymphoblastic leukemias (B-ALL), where SFs are not mutated. By comparing them to normal pro-B cells, we found thousands of aberrant local splice variations (LSVs) per sample, with 279 LSVs in 241 genes present in every comparison. These genes were enriched in RNA processing pathways and encoded ~100 SFs, e.g. hnRNPA1. hnRNPA1 3'UTR was most pervasively misspliced, yielding the transcript subject to nonsense-mediated decay. Thus, we knocked it down in B-lymphoblastoid cells, identified 213 hnRNPA1-dependent splicing events, and defined the hnRNPA1 splicing signature in pediatric leukemias. One of its elements was DICER1, a known tumor suppressor gene; its LSVs involved the 5' UTR, suggestive of splicing as a mechanism of translational deregulation. Additionally, we searched for LSVs in other leukemia and lymphoma drivers and discovered 81 LSVs in 41 genes. 77 LSVs were confirmed using two large independent B-ALL RNA-seq datasets. In fact, the twenty most common B-ALL drivers showed higher prevalence of aberrant splicing than of somatic mutations. Thus, post-transcriptional deregulation of SF can drive widespread changes in B-ALL splicing and likely contribute to disease pathogenesis. Overall design: We profiled hnRNPA1 Ctrl and hnRNPA1 knockdown with 2 replicates each.
Aberrant splicing in B-cell acute lymphoblastic leukemia.
Specimen part, Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Ulipristal blocks ovulation by inhibiting progesterone receptor-dependent pathways intrinsic to the ovary.
Specimen part, Treatment
View SamplesUlipristal acetate (UPA), also referred to as VA/CDB-2914, is a new and promising emergency contraceptive. It is a selective progesterone receptor modulator (SPRM) that has been approved in Europe and the USA for emergency contraception.
Ulipristal blocks ovulation by inhibiting progesterone receptor-dependent pathways intrinsic to the ovary.
Specimen part, Treatment
View SamplesPrevious studies have shown that PR is a critical regulator of ovulation. The PR-null mice (PRKO) failed to ovulate due to a failure in the rupture of the preovulatory follicles.
Ulipristal blocks ovulation by inhibiting progesterone receptor-dependent pathways intrinsic to the ovary.
Specimen part
View Samplesgene expression at 6h of differentiation of Human endometrial stromal cell expressing either or both of PRA and PRB
Roles of progesterone receptor A and B isoforms during human endometrial decidualization.
Specimen part, Treatment
View SamplesEstrogen and progesterone are important regulators of human endometrial differentiation. These steroid hormones act, at least in part, through their nucelar receptors. Role of estrogen receptor alpha (ESR1) during human endometrial differentiation is still unclear.
Roles of Estrogen Receptor-α and the Coactivator MED1 During Human Endometrial Decidualization.
Specimen part
View Samples