Phyllodes tumours of the breast are uncommon fibroepithelial neoplasms which pose management challenges due to difficulties in accurate prediction of clinical behaviour, as histological assessment has its limitations. Molecular studies have improved the understanding of these rare tumours but such findings are scant. We aimed to investigate genetic aberrations in phyllodes tumours stratified according to clinical behaviour, to identify potential genes contributing to disease progression.
View Article and Find Full Text PDFG3139 (Genasense), an 18mer phosphorothioate antisense oligonucleotide targeted to the initiation codon region of the Bcl-2 messenger RNA (mRNA), downregulates Bcl-2 protein and mRNA expression in many cell lines. However, both the in vitro and in vivo mechanisms of action of G3139 are still uncertain. The isosequential L-deoxyribose enantiomer L-G3139, which does not downregulate Bcl-2 expression, was synthesized to study the role of the Bcl-2 protein in melanoma cells.
View Article and Find Full Text PDFAm J Physiol Cell Physiol
April 2007
G3139, an antisense Bcl-2 phosphorothioate oligodeoxyribonucleotide, induces apoptosis in melanoma and other cancer cells. This apoptosis happens before and in the absence of the downregulation of Bcl-2 and thus seems to be Bcl-2-independent. Binding of G3139 to mitochondria and its ability to close voltage-dependent anion-selective channel (VDAC) have led to the hypothesis that G3139 acts, in part, by interacting with VDAC channels in the mitochondrial outer membrane (21).
View Article and Find Full Text PDFProc Natl Acad Sci U S A
May 2006
G3139, an 18-mer phosphorothioate antisense oligonucleotide targeted to the initiation codon region of the Bcl-2 mRNA, can induce caspase-dependent apoptosis via the intrinsic mitochondrial pathway in 518A2 and other melanoma cells. G3139-mediated apoptosis appears to be independent of its ability to down-regulate the expression of Bcl-2 protein, because the release of mitochondrial cytochrome c precedes in time the down-regulation of Bcl-2 protein expression. In this study, we demonstrate the ability of G3139 and other phosphorothioate oligonucleotides to bind directly to mitochondria isolated from 518A2 cells.
View Article and Find Full Text PDFG3139 is an 18mer phosphorothioate oligonucleotide targeted to the initiation codon region of the Bcl-2 mRNA. Because of the ability of this antisense construct to downregulate the expression of Bcl-2 mRNA and protein, it has entered phase III clinical trials in a number of human cancers, including advanced melanoma. However, the actual mechanism of this agent is far from certain.
View Article and Find Full Text PDFIn a previous study, we showed that G3139, an antisense phosphorothioate oligonucleotide that down-regulates the expression of Bcl-2 protein, did not cause chemosensitization of 518A2 melanoma cells. In this work, we show that G3139, and the 2-base mismatch, G4126, can initiate apoptosis in this and other melanoma cell lines as shown by increased cell surface Annexin V expression, typical nuclear phenotypic changes as assessed by 4',6-diamidino-2-phenylindole staining, activation of caspase-3 (but not caspase-8) and Bid, appearance of DEVDase (but not IETDase) activity, and cleavage of poly(ADP-ribose)-polymerase 1. Depolarization of the mitochondrial membrane occurs as a relatively late event.
View Article and Find Full Text PDFPurpose: Inhibition of the function of Bcl-2 protein has been postulated to sensitize cells to cytotoxic chemotherapy. G3139 (Genasense) is a phosphorothioate anti-Bcl-2 antisense oligonucleotide, but its mechanism of action is uncertain. The aim of the present work is to investigate inhibition of Bcl-2 expression in 518A2 melanoma cells, the cell line on which recent phase II and phase III clinical trials employing this agent were based.
View Article and Find Full Text PDFPurpose: G3139 is an antisense bcl-2 phosphorothioate oligodeoxyribonucleotide that is currently being evaluated in Phase III clinical trials in several human cancers. The aim of the present work was to further identify the apparent non-bcl-2-dependent mechanism of this action of this compound in PC3 prostate cancer cells.
Experimental Design: We performed Affymetrix U95A oligonucleotide microarray studies on mRNA isolated from cells treated with G3139 and related oligonucleotides.
Purpose: Inhibition of the function of the bcl-2 protein has been postulated to sensitize cells to cytotoxic chemotherapy, and thus provides an attractive target for investigative therapies. G3139, a phosphorothioate antisense oligonucleotide targeted to the initiation codon region of the bcl-2 mRNA, is currently being evaluated in several Phase II and Phase III clinical trials. However, the mechanism of action of this molecule appears to depend on a combination of antisense plus nonantisense events.
View Article and Find Full Text PDFThe binding of fluorescein-labeled polyamidoamine dendritic polymers (dendrimers) to the surface of individual fibroblast cells has been quantitatively measured using confocal fluorescence microscopy. Because the binding of these polymers is not strong, significant fluorescence from polymers in solution complicates the measurement, even using confocal optics. To overcome this difficulty, we have developed a new method employing a cell-entrapped marker dye to determine the extracellular volume in each voxel.
View Article and Find Full Text PDFThe development of antisense technology has focused on improving methods for oligonucleotide delivery into cells. In the present work, we describe a novel strategy for oligonucleotide delivery based on a bifunctional peptide composed of a C-terminal protamine-fragment that contains a DNA-binding domain and an N-terminal nuclear localization signal sequence derived from the SV40 large-T antigen (The sequences of two of the peptides are R6WGR6-PKKKRKV [s-protamine-NLS] and R4SR6FGR6VWR4-PKKKRKV [l-protamine-NLS]). We demonstrated, by intrinsic fluorescence quenching, that peptides of this class form complexes with oligodeoxynucleotides.
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