Background Dysregulation of microRNA (miRNA) expression is implicated in cancer development and progression by modulating oncogenes or tumor suppressors at the post-transcriptional level. Methods To investigate the role of miRNAs in prostate cancer (PCa) progression, we performed small RNA-sequencing (RNA-seq) analysis in androgen-dependent LNCaP cells and LNCaP-derived castration-resistant prostate cancer (CRPC) C4-2B cells. For functional validation, we specifically investigated miR-193a-3p, which is highly upregulated in C4-2B cells and modulated by the androgen receptor (AR).
View Article and Find Full Text PDFBackground: Despite advances in early diagnosis and treatment of cancer patients, metastasis remains the major cause of mortality. TP53 is one of the most frequently mutated genes in human cancer, and these alterations can occur during the early stages of oncogenesis or as later events as tumors progress to more aggressive forms. Previous studies have suggested that p53 plays a role in cellular pathways that govern metastasis.
View Article and Find Full Text PDFMethylation of the CpG-rich region (CpG island) overlapping a gene's promoter is a generally accepted mechanism for silencing expression. While recent technological advances have enabled measurement of DNA methylation and expression changes genome-wide, only modest correlations between differential methylation at gene promoters and expression have been found. We hypothesize that stronger associations are not observed because existing analysis methods oversimplify their representation of the data and do not capture the diversity of existing methylation patterns.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
August 2013
Emerging evidence suggests that ventricular electrical remodeling (VER) is triggered by regional myocardial strain via mechanoelectrical feedback mechanisms; however, the ionic mechanisms underlying strain-induced VER are poorly understood. To determine its ionic basis, VER induced by altered electrical activation in dogs undergoing left ventricular pacing (n = 6) were compared with unpaced controls (n = 4). Action potential (AP) durations (APDs), ionic currents, and Ca(2+) transients were measured from canine epicardial myocytes isolated from early-activated (low strain) and late-activated (high strain) left ventricular regions.
View Article and Find Full Text PDFSeveral Bcl2 family proteins are expressed both as mitochondrial-targeted full-length and as cytosolic truncated alternately spliced isoforms. Recombinantly expressed shorter Bcl2 family isoforms can heterotypically bind to and prevent mitochondrial localization of their full-length analogs, thus suppressing their activity by sequestration. This "sponge" role requires 1:1 expression stoichiometry; absent this an alternate role is suggested.
View Article and Find Full Text PDFAdvanced prostate cancer is characterized by incurable castration-resistant progression and osteoblastic bone metastasis. While androgen deprivation therapy remains the primary treatment for advanced prostate cancer, resistance inevitably develops. Importantly, mounting evidence indicates that androgen receptor (AR) signaling continues to play a critical role in the growth of advanced prostate cancer despite androgen deprivation.
View Article and Find Full Text PDFThe androgen receptor (AR) is a ligand-inducible transcription factor that mediates androgen action in target tissues. Upon ligand binding, the AR binds to thousands of genomic loci and activates a cell-type specific gene program. Prostate cancer growth and progression depend on androgen-induced AR signaling.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
November 2010
The increased incidence of arrhythmia in the healing phase after infarction has been linked to remodeling in the epicardial border zone (EBZ). Ionic models of normal zone (NZ) and EBZ myocytes were incorporated into one-dimensional models of propagation to gain mechanistic insights into how ion channel remodeling affects action potential (AP) duration (APD) and refractoriness, vulnerability to conduction block, and conduction safety postinfarction. We found that EBZ tissue exhibited abnormal APD restitution.
View Article and Find Full Text PDFIon-channel function is determined by its gating movement. Yet, molecular dynamics and electrophysiological simulations were never combined to link molecular structure to function. We performed multiscale molecular dynamics and continuum electrostatics calculations to simulate a cardiac K(+) channel (I(Ks)) gating and its alteration by mutations that cause arrhythmias and sudden death.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
April 2009
Computational models of cardiac myocytes are important tools for understanding ionic mechanisms of arrhythmia. This work presents a new model of the canine epicardial myocyte that reproduces a wide range of experimentally observed rate-dependent behaviors in cardiac cell and tissue, including action potential (AP) duration (APD) adaptation, restitution, and accommodation. Model behavior depends on updated formulations for the 4-aminopyridine-sensitive transient outward current (I(to1)), the slow component of the delayed rectifier K(+) current (I(Ks)), the L-type Ca(2+) channel current (I(Ca,L)), and the Na(+)-K(+) pump current (I(NaK)) fit to data from canine ventricular myocytes.
View Article and Find Full Text PDFCa(2+)/calmodulin-dependent protein kinase II is a multifunctional serine/threonine kinase with diverse cardiac roles including regulation of excitation contraction, transcription, and apoptosis. Dynamic regulation of CaMKII activity occurs in cardiac disease and is linked to specific disease phenotypes through its effects on ion channels, transporters, transcription and cell death pathways. Recent mathematical models of the cardiomyocyte have incorporated limited elements of CaMKII signaling to advance our understanding of how CaMKII regulates cardiac contractility and excitability.
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