Unknown,Transcriptomics,Genomics,Proteomics

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Alterations in tumour necrosis factor signaling pathways associated with cytotoxicity and resistance to taxanes in tumour cells.

ABSTRACT: The taxanes are widely used in the treatment of breast and other cancers. While their cytotoxicity has been attributed to the induction of cell cycle arrest in mitosis through the stabilization of microtubules, we found that docetaxel promotes soluble tumor necrosis factor alpha (TNF-alpha production in MCF-7 breast tumor cells. TNF-alpha induces apoptotic cell death in a variety of cell types by binding to one of its receptors (TNFR1) which promotes death-inducing signaling complex (DISC) formation. Consistent with this view, we also report that selection of MCF-7 cells for survival in increasing concentrations of paclitaxel or docetaxel results in selection of drug-resistant variants that are resistant to TNF-alpha cytotoxicity. MCF-7 cells selected to 3-5 nM docetaxel produced >30-fold more TNF-alpha than control MCF-7CC cells but had strongly reduced levels of TNFR1. In contrast, expression of TNFR2 was unchanged, resulting in enhanced cell survival through the activation of the NF-kappaB p50 and p65 subunits. Gene expression profiling of docetaxel resistant MCF-7 cells compared to parental MCF-7 cells was performed for the changes of TNF related genes, and also confirmed in ovarian cell line A2780. Two docetaxel resistant cell lines of breast MCF-7 and ovarian A2780 were generated for gene expression profilling. Two colour microarray of Agilent whole human genome nucleotide arrays was conducted with two replicate of both forward and reverse labellings for MCF-7. Four arrays were used for this experiments. And it was four replicate of both forward and reverse labellings for A2780 cells. Eight arrays were used for this experiments

ORGANISM(S): Homo sapiens

SUBMITTER: baoqing guo

PROVIDER: E-GEOD-26129 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Background: Current protocols for the treatment of ovarian cancer include combination chemotherapy with a platinating agent and a taxane. However, many patients experience relapse of their cancer and the development of drug resistance is not uncommon, making successful second line therapy difficult to achieve. The objective of this study was to develop a cell line resistant to both carboplatin and docetaxel (dual drug resistant ovarian cell line A2780CBNDXL), along with single agent resistant lines (docetaxel resistant A2780DXL and carboplatin resistant A2780CBN), to investigate the mechanisms which underlie the development of dual drug resistance. Methods: The A2780 epithelial ovarian cancer cell line was used to select for isogenic carboplatin, docetaxel and dual drug resistant cell lines. A selection method of gradually increasing drug doses was implemented to avoid clonal selection. Resistance was confirmed using a clonogenic assay. Changes in gene expression associated with the development of drug resistance were determined by microarray analysis compared to parental co-culture control A2780CC. Changes in selected genes were validated by QPCR and immunoblotting. Results: Three isogenic cell lines were developed and resistance to each drug or the combination of drugs was confirmed. Development of resistance was accompanied by a reduced growth rate. The microarray and QPCR analyses showed that unique changes in gene expression occurred in the dual drug resistant cell line and that genes known to be involved in resistance could be identified in all cell lines. Conclusions: Novel changes in gene expression can occur in the development of dual drug resistance, indicating that dual drug resistance is not a simple combination of the changes occurring in single agent resistance Carboplatin, docetaxel (GSE26129) and carboplatin/docetaxel dual resistant cell lines of ovarian A2780 were generated for gene expression profilling. Two colour microarray of Agilent whole human genome nucleotide arrays was conducted with two replicate of both forward and reverse labellings for each cell line. Four arrays were used for this experiments. And it was four replicate of both forward and reverse labellings for A2780 cells. Eight arrays were used for this experiments

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