The gene coding for RNA binding motif protein 35A (RBM35A) is inactivated by frameshift mutations in an LS180 colon carcinoma cell line and in approximately in 50% of colon tumors with microsatellite instability. To get insight into the mechanism of action of these putative tumor suppressor gene we expressed functional copy of the RBM35A cDNA in the LS180 cells. We analyzed alterations in mRNA profiles in total and in polysomal fraction of mRNA in LS180 cells in response to expressing RBM35A gene under Tet off tetracycline inducible promoter.
RNA-binding motif protein 35A is a novel tumor suppressor for colorectal cancer.
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View SamplesWe used a modification of GINI analysis to identify genes containing premature translation termination codons (PTC) generated by nonsense or frameshift mutations in prostate cancer cell lines. The analysis was performed in two steps. In the first step nonsense mediated mRNA decay (NMD) was inhibited in prostate cancer cell lines using incubation with medium containing caffeine for 4 hours. Gene expression analysis of caffeine treated or untreated cells after this step detects mRNA accumulation that takes place for genes containing PTC and as well as for genes that show induction of transciption due to stress caused by NMD inhibition. In the second step either both transcription and NMD or transcription only are blocked by incubating cell in a medium containing either both actinomycin D and caffeine or actinomacin D only for 4 hours. Gene expression analysis after this second step detects mRNA degradation for genes containing PTC as well as for genes that show induction of transciption due to stress caused by NMD inhibition. The efficiency of mRNA degradation for genes containing PTC during this step depends on whether NMD is inhibited or not. The efficiency of mRNA degradation for stress response genes does not depend on whether NMD is inhibited or not.
Par-3 partitioning defective 3 homolog (C. elegans) and androgen-induced prostate proliferative shutoff associated protein genes are mutationally inactivated in prostate cancer cells.
Cell line, Treatment
View SamplesInhibition of the nonsense mediated decay (NMD) mechanism in cells results in stabilization of transcripts carrying premature translation termination codons. A strategy referred to as gene indentification by NMD inhibition (GINI) has been proposed to identify genes carrying nonsense mutations (Noensie & Dietz, 2001). Genes containing frameshift mutations in colon cancer cell line have been identifying mutatnt genes using GINI, we have now further improved the strategy. In this approach, inhibition of NMD with emetine is complemented with inhibiting NMD by blocking the phosphorylation of the hUpf1 protein with caffeine. In addition, to enhance the GINI strategy, comparing mRNA level alterations produced by inhibiting transcription alone or inhbiiting transcription together with NMD following caffeine pretreatment were used for the efficient identification of false positives produced as a result of stress response to NMD inhibition. To demonstrate the improved efficiency of this approach, we analyzed colon cancer cell lines showing microstellite instability. Bi-allelic inactivating mutations were found in the FXR1, SEC1L1, NCOR1, BAT3, PHD14, ZNF294, C190ORF5 genes as well as genes coding for proteins with yet unknown functions.
Identifying candidate colon cancer tumor suppressor genes using inhibition of nonsense-mediated mRNA decay in colon cancer cells.
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View SamplesPresence of ectopic lipid droplets (LDs) in cardiac muscle is associated to lipotoxicity and tissue dysfunction. However, presence of LDs in heart is also observed in physiological conditions, such as at times when cellular energy needs and energy production from mitochondria fatty acid (FA) -oxidation are high (fasting). This suggests that development of tissue lipotoxicity and dysfunction is not simply due to the presence of LDs in cardiac muscle but due at least in part to alterations in LD function. To examine the function of cardiac LDs, we obtained transgenic mice with heart-specific plin5 over-expression (MHC-plin5), a member of the perilipin protein family. Hearts from MHC-plin5 mice expressed at least 4-fold higher levels of plin5 and exhibit a 3.5- fold increase in triglyceride content versus non-transgenic littermate. Chronic cardiac excess of LDs was found to result in mild heart dysfunction with decreased expression of PPAR target genes, decreased mitochondria function and left ventricular concentric hypertrophia. Lack of more severe heart function complications may have been prevented by a strong increased expression of oxidative induced genes via NF-E2-related factor 2 anti-oxidative pathway. Perilipin 5 regulates the formation and stabilization of cardiac LDs, and promotes cardiac steatosis without major heart function impairment.
Cardiomyocyte-specific perilipin 5 overexpression leads to myocardial steatosis and modest cardiac dysfunction.
Sex, Specimen part
View SamplesThe objective of this study is to: 1) Characterize the innate immune responsiveness of patients with inborn errors in Toll-IL1 receptor signaling pathway (IRAK4, MyD88 deficiencies) compared to healthy subjects, through the analysis of blood leukocytes' transcriptional profiles after stimulation with ligands for the whole set of Toll-like receptors and IL-1Rs plus whole bacteria. 2) Understand the redundancies in TLR pathway in humans. 3) Explore the use of blood profiling approaches to assess the immune status of an individual by using Primary Immune Deficiencies as a proof of principle.
A narrow repertoire of transcriptional modules responsive to pyogenic bacteria is impaired in patients carrying loss-of-function mutations in MYD88 or IRAK4.
Sex, Race
View SamplesApproximately 30% of women diagnosed with ERa breast cancer relapse with metastatic disease following adjuvant treatment with endocrine therapies. The connection between acquisition of drug resistance and invasive potential is poorly understood. In this study, we demonstrate that the type II keratin topological associating domain (TAD) undergoes epigenetic reprogramming in cells that develop resistance to aromatase inhibitors (AI), leading to keratin 80 (KRT80) upregulation. In agreement, an increased number of KRT80-positive cells are observed at relapse in vivo while KRT80 expression associates with poor outcome using several clinical endpoints. KRT80 expression is driven by de novo enhancer activation by sterol regulatory element-binding protein 1 (SREBP1). KRT80 upregulation directly promotes cytoskeletal rearrangements at the leading edge, increased focal adhesion maturation and cellular stiffening, which collectively promote cancer cell invasion. Shear-wave elasticity imaging of tumors from prospectively recruited patients shows that KRT80 levels correlate with stiffer tumors in vivo. Collectively, our data uncover an unpredicted and potentially targetable direct link between epigenetic and cytoskeletal reprogramming promoting cell invasion in response to chronic AI treatment. Overall design: Total RNA profiling of MCF7 breast adenocarcinoma cell line and MCF7 overexpressing KRT80. Experiments were carried out in four replicates in both cell lines.
SREBP1 drives Keratin-80-dependent cytoskeletal changes and invasive behavior in endocrine-resistant ERα breast cancer.
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