Polarity defects are a hallmark of most carcinomas. Cells from invasive micropapillary carcinomas (IMPCs) of the breast are characterized by a striking cell polarity inversion and represent a good model for the analysis of polarity abnormalities. We have performed an in-depth investigation of polarity alterations in 24 IMPCs, compared with invasive carcinomas of no special type (ICNST).
LIN7A is a major determinant of cell-polarity defects in breast carcinomas.
Specimen part
View SamplesAlterations of chromatin modifiers are frequent in cancer but their functional consequences remain often unclear. Focusing on the Polycomb protein EZH2 that deposits H3K27me3 mark, we showed that its high expression in solid tumors is a consequence, and not a cause, of tumorigenesis. In mouse and human models, EZH2 is dispensable for prostate cancer development and restrains breast tumorigenesis. High EZH2 expression in tumors results from a tight coupling to proliferation to ensure H3K27me3 homeostasis. However, this process is malfunctioning in breast cancer. Low EZH2 expression relative to proliferation and mutations in Polycomb genes are actually of poor prognosis and occur in metastases. We show that while altered EZH2 activity consistently modulates a subset of its target genes, it promotes a wider transcriptional instability. Importantly, transcriptional changes consequent to EZH2 loss are predominantly irreversible. Our study provides an unexpected understanding of EZH2's contribution to solid tumors with important therapeutic implications.
Impaired PRC2 activity promotes transcriptional instability and favors breast tumorigenesis.
Specimen part
View SamplesPolycomb Repressive Complex 2 (PRC2) plays a key role in controlling transcriptional repression. It is thought to act at the level of the chromatin, where its enzymatic subunits Ezh1 and Ezh2 catalyse the di/tri-methylation of histone H3 on its lysine 27 (H3K27me3).
Impaired PRC2 activity promotes transcriptional instability and favors breast tumorigenesis.
Specimen part
View SamplesScreening small molecules and drugs for activity to modulate alternative splicing, we found that amiloride, distinct from four other intracellular pH-affecting analogues, could normalize the splicing of BCL-X, HIPK3 and RON/MISTR1 transcripts in human hepatocellular carcinoma Huh-7 cells. To elucidate the underlying mechanisms, our proteomic analyses of amiloride-treated cells detected hypo-phosphorylation of splicing factor SF2/ASF and also decreased levels of SRp20 and two un-identified SR proteins. We further observed decreased phosphorylation of AKT, ERK1/2 and PP1, while increased phosphorylation of p38 and JNK, suggesting that amiloride treatment down-regulated kinases and up-regulated phosphatases in the signal pathways known to affect the splicing factor protein phosphorylation. The amiloride effects of splicing factor protein hypo-phosphorylation andnormalizedoncogenic RNA splicing were both abrogated by pre-treatment with a PP1 inhibitor. We then performed global exon array analysis of Huh-7 cells treated with amiloride for 24 hours. Using gene array chips (Affymetrix GeneChip Human Exon 1.0 ST Array of >518000 exons of 42974 genes) for exon array analysis (set parameters of correlation coefficient 0.7, splicing index -1.585 , and log2 ratio -1.585), we found that amiloride influenced the splicing patterns of 551 genes involving at least 584 exons, which included 495 known protein-coding genes involving 526 exons, many of which play key roles in functional networks of ion transport, extracellular matrix, cytoskeletons and genome maintenance. Cellular functional analyses revealed subsequent invasion and migration defects, cell cycle disruption, cytokinesis impairment, and lethal DNA degradation in amiloride-treated Huh-7 cells. This study thus provides mechanistic underpinnings for exploiting small molecule modulation of abnormal RNA splicing for cancer therapeutics.
Small molecule amiloride modulates oncogenic RNA alternative splicing to devitalize human cancer cells.
Cell line
View SamplesAlternative splicing is a mechanism for increasing the protein variety of a limited number of genes. Studies have shown that aberrant regulations of the alternative splicing of apoptotic gene transcripts may contribute to the development of cancer. In this study, we isolated 4ß-Hydroxywithanolide E (4bHWE) from the traditional herb Physalis peruviana, and analyzed its biological effects in cancer cells. The results demonstrated that 4bHWE modulates the alternative splicing of apoptotic genes (e.g., HIPK3, SMAC/DIABLO, and SURVIVIN), changes the expression level of splicing factors (e.g., hnRNP C1/C2, ASF/SF2, SRp20, and SRp55), and induces histone tail posttranslational modifications (e.g., H3K27me1, H3K27me2, H3K36me3, and H3K79me1). Pretreatment with okadaic acid to inhibit protein phosphatase-1 could partly relieve the effects of 4bHWE on the alternative splicing of HIPK3 and SMAC/DIABLO transcripts, as well as on the dephosphorylation of ASF/SF2. Genome-wide detection of alternative splicing further indicated that several other apoptosis-related genes are also regulated by 4bHWE, including APAF1, CARP-1, and RIPK1. Moreover, we extended our study to apoptosis-associated molecules, detecting an increasing level of CASPASE-3 activity and cleavage of poly ADP-ribose polymerase in 4bHWE-induced apoptosis. Furthermore, in vivo experiments showed that the treatment of tumor-bearing mice with 4bHWE resulted in a marked decrease of tumor size and weight. Taken together, this study is the first to show that 4bHWE affects alternative splicing through the modulations of splicing factors, providing a novel view of the antitumor mechanism of 4bHWE. Overall design: Examination of the global genes with altered alternative splicing in 4bHWE-treated Huh-7 cells.
4β-Hydroxywithanolide E Modulates Alternative Splicing of Apoptotic Genes in Human Hepatocellular Carcinoma Huh-7 Cells.
Specimen part, Treatment, Subject
View SamplesTET-family dioxygenases oxidize 5-methylcytosine (5mC) in DNA, and exert tumor suppressor activity in many types of cancers. Even in the absence of TET coding region mutations, TET loss-of-function is strongly associated with cancer. We show that acute elimination of TET function induces the rapid development of an aggressive, fully-penetrant and cell-autonomous myeloid leukemia in mice, pointing to a causative role for TET-loss-of-function in this myeloid malignancy. Phenotypic and transcriptional profiling showed aberrant differentiation of hematopoietic stem/ progenitor cells, impaired erythroid and lymphoid differentiation and strong skewing to the myeloid lineage, with only a mild relation to changes in DNA modification. We also observed progressive accumulation of DNA damage and strong impairment of DNA break repair, suggesting a key role for TET proteins in maintaining genomic integrity. Overall design: Jungeun, An
Acute loss of TET function results in aggressive myeloid cancer in mice.
Specimen part, Subject
View SamplesThe study demontrates differences in the transcriptome ( both of protein coding transcripts and long non-coding RNAs) in the unilateral ureteric obstruction model of renal fibrosis. Overall design: Renal tissue was studied from animals undergoing sham operation (as controls) or right ureteric ligation. Animals were sacrificed 2 and 8 days following ligation and the right kidney tissue was examined.
Whole-transcriptome analysis of UUO mouse model of renal fibrosis reveals new molecular players in kidney diseases.
Sex, Age, Specimen part, Cell line, Subject
View SamplesWe demonstrate that GLUT4 up-regulation significantly increased cell migration and invasion in lower magligance head and neck cancer cell lines in vitro.
Glucose transporter 4 promotes head and neck squamous cell carcinoma metastasis through the TRIM24-DDX58 axis.
Specimen part, Cell line
View SamplesNatural killer T (NKT) cells have immune stimulatory or inhibitory effects on the immune response that are context-dependent. This may be attributed in part to the existence of functional NKT cell subsets; however, these functional subsets have only been characterized on the basis of differential expression of a few transcription factors and cell surface molecules. Here we have analyzed purified populations of thymic NKT cell subsets at both the transcriptomic and epigenomic levels, and by single-cell RNA sequencing. Our data indicate that despite their similar antigen specificity, the functional NKT cell subsets are highly divergent populations characterized by many gene expression and epigenetic differences. Therefore the thymus imprints innate-like NKT cells with novel combinations of properties, including differences in proliferative capacity, homing, and effector functions that were not previously anticipated. Overall design: Analysis of single cell transcriptomic heterogeneity in mouse Va14 iNKT thymocyte subsets (NKT1, NKT2, NKT17 and NKT0). Samples were generated from individual experiment using a pool of thymocytes prepared from five five-week old C57BL/6J females. NKT cells subtypes were isolated from thymuses and directly sorted by flow cytometry into lysis buffer (96 well plate single cell sort). The preparation of samples occurred in 2 different batches (both having a equal representation of the different cell populations).
Innate-like functions of natural killer T cell subsets result from highly divergent gene programs.
Sex, Age, Specimen part, Cell line, Subject
View SamplesWe report the expression profiles of MCF10A cells encapsulated in hydrogels of varying stiffness and composition. Cells were encapsulated for 7 days in either 1.) soft alginate and reconstituted basement membrane (rBM), 2.) stiff alginate and rBM, 3,) soft col-1 and rBM, or 4.) stiff col-1. We find global gene expression changes in response to enhanced ECM stiffness, independent of expression changes in response to col-1 exposure. These results provide a comprehensive study of the gene expression changes associated with increased ECM stiffness in addition to the gene expression changes associated with increased col-1 concentration in combination with, and independent of, ECM stiffness. Overall design: Expression profiling of MCF10A cells in four hydrogel conditions were sequenced in duplicate via Illumina HiSeq.
YAP-independent mechanotransduction drives breast cancer progression.
Specimen part, Cell line, Subject
View Samples