Acquired alkylating drug resistance of a human ovarian carcinoma cell line is unaffected by altered levels of pro- and anti-apoptotic proteins

Roy, Gargi; Horton, Julie K.; Roy, Rabindra; Denning, Timothy L.; Mitra, Sankar; Boldogh, István

doi:10.1038/sj.onc.1203318

Cited by 20 publications

(19 citation statements)

References 27 publications

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“…Addition of NO has no effect (bar 7) on cell growth, although NOO À (1 nM) decreases (bar 8) LD 50 (Figure 1b) and signals cell death by apoptosis, as earlier evidenced in Cbl-treated A2780-sensitive cells. 2,15 Expression profiling of Cbl-sensitive A2780 and -resistant A2780/100 cells shows the expression difference for a set of genes, and those changes in gene expression due to Cbl-induced resistance in A2780/100 cells are not apparent. Validation of microarray gene expression by real-time PCR Among differentially regulated genes, five genes (CDK6, CLARP2, TSPYL4, RYBP and CYR61) are selected and their mRNA expressions are validated by real-time PCR (TaqMan method).…”

Section: Resultsmentioning

confidence: 99%

“…However, overexpression or silencing BCL-xl does not improve Cbl sensitivity in A2780/100-resistant cells. 2 Similarly, BCL2l1 overexpression does not decrease etoposide-induced sensitivity in thymic lymphoma cells. 51 Nevertheless, no deamidation 52 of BCL2L1 or any breakdown of the protein is observed in these cell lines with or without Cbl and Cbl cos treatment.…”

Section: Discussionmentioning

confidence: 97%

“…2 Briefly, 200 cells in each 60 mm dish are allowed to attach for about 4 h, exposed to increasing concentration of Cbl for 1 h, followed by addition of growth media containing 10% FBS. Nontoxic doses of H 2 O 2 , GO and NOO À are added at 1, 3, 6 and 9 h after Cbl treatment.…”

Section: Clonogenic Survival Assaymentioning

confidence: 99%

“…Modulation of BCL2L1, Bax and GSTp by transgenic overexpression or gene silencing does not significantly alter resistance to Cbl, Cpl or etoposide, indicating that the primary mechanism of drug resistance in A2780/100 cells is not due to enhanced drug detoxification or enhanced expression of antiapoptotic proteins. 1,2 Cbl first induces DNA monoalkyl adducts, followed by alkyl cross-links. However, Cbl resistance of A2780/100 cells does not elevate the expressions of N-methylpurine-DNA glycosylase, O-6-methylguanine-DNA methyltransferase, ERCC-4 2,3 or base excision repair proteins such as APE1 and DNA b-polymerase 3 in these cells.…”

Section: Introductionmentioning

confidence: 99%

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Gene network analysis of oxidative stress-mediated drug sensitivity in resistant ovarian carcinoma cells

Maiti

2009

Pharmacogenomics J

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Drug resistance in cancer cells involves complex molecular mechanisms and ovarian carcinoma cells become resistant to chlorambucil (Cbl) after continuous treatment. This drug-and ionizing radiation-resistant cells have lower level of endogenous ROS (reactive oxygen species) compared with sensitive cells. Elevation of the cellular ROS level by exogenous ROS generation increases the sensitivity of Cbl to resistant cells. In contrast, antioxidants prevent the sensitization of resistant cells to Cbl by H 2 O 2 , COS (chronic oxidative stress) or NOO À . The molecular mechanism of drug sensitivity with COS has been investigated by microarray gene expressions followed by gene network analysis and it reveals that a cdc42/rac1 guanine exchange factor, ARHGEF6, with p53 and DNA-Pkc (PRKDC) is central to induce apoptosis in Cbl cos (Cbl with COS) cells. mRNA and protein levels of major gene network pathway differ significantly in Cbl cos cells than in Cbltreated cells. Moreover, DNA-PKc physically interacts with ARHGEF6 and p53 mostly in the nucleus of Cbl-treated cells, whereas in Cbl cos -treated cells, its interactions are mostly in the cytoplasm. These results suggest that low doses of Cbl and very low doses of COS together kill Cbl-resistant ovarian carcinoma cells and ARHGEF6 signaling may have an instrumental role in induction of apoptosis in Cbl cos cells.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 97%

Section: Clonogenic Survival Assaymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Gene network analysis of oxidative stress-mediated drug sensitivity in resistant ovarian carcinoma cells

Maiti

2009

Pharmacogenomics J

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“…(a) loss of proficiency of the mismatch repair pathway (MMR) due to methylation and silencing of the hMLH1 gene (Brown et al, 1997) (Plumb et al, 2000); (b) accumulation of the mutant (inactive) form of the p53 tumour suppressor gene (Brown et al, 1993); (c) elevated GSH cellular content and a concomitant increase in expression of MRP2 (Kool et al, 1997) and (d) altered DNA damage recognition, cellular signalling and DNA repair (Roy et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

In vitro and in vivo activity and cross resistance profiles of novel ruthenium (II) organometallic arene complexes in human ovarian cancer

et al. 2002

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Ruthenium complexes offer the potential of reduced toxicity, a novel mechanism of action, non-cross resistance and a different spectrum of activity compared to platinum containing compounds. Thirteen novel ruthenium(II) organometallic arene complexes have been evaluated for activity (in vitro and in vivo) in models of human ovarian cancer, and cross-resistance profiles established in cisplatin and multi-drug-resistant variants. A broad range of IC 50 values was obtained (0.5 to 4100 mM) in A2780 parental cells with two compounds (RM175 and HC29) equipotent to carboplatin (6 mM), and the most active compound (HC11) equipotent to cisplatin (0.6 mM). Stable bi-dentate chelating ligands (ethylenediamine), a more hydrophobic arene ligand (tetrahydroanthracene) and a single ligand exchange centre (chloride) were associated with increased activity. None of the six active ruthenium(II) compounds were cross-resistant in the A2780cis cell line, demonstrated to be 10-fold resistant to cisplatin/carboplatin by a mechanism involving, at least in part, silencing of MLH1 protein expression via methylation. Varying degrees of cross-resistance were observed in the P-170 glycoprotein overexpressing multi-drug-resistant cell line 2780 AD that could be reversed by co-treatment with verapamil. In vivo activity was established with RM175 in the A2780 xenograft together with non-cross-resistance in the A2780cis xenograft and a lack of activity in the 2780 AD xenograft. High activity coupled to non cross-resistance in cisplatin resistant models merit further development of this novel group of anticancer compounds.

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Enhanced γ‐glutamylcysteine synthetase activity decreases drug‐induced oxidative stress levels and cytotoxicity

Das

Bácsi

Shrivastav³

et al. 2006

Molecular Carcinogenesis

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Multidrug resistance of cancer cells can be intrinsic or acquired and occurs due to various reasons, including increased repair of genotoxic damage, an enhanced ability to remove/detoxify chemical agents, or reactive oxygen species (ROS), and repression of apoptosis. Human A2780/100 ovarian carcinoma cells exhibit resistance to DNA cross-linking agents, chlorambucil (Cbl), cisplatin (Cpl), melphalan (Mel), and ionizing radiation (IR) compared to the parental cell line, A2780. In the present study, we show that when A2780/100 and A2780 cells were treated with Cbl, GSH was extruded via methionine or cystathionine-inhibitable transporters of intact plasma membrane. GSH loss was followed by a rapid increase in ROS levels. The resistant, but not drug-sensitive cells normalized the intracellular GSH concentration along with ROS levels within 4-6 h after Cbl addition, and survived drug treatment. Normalization of GSH and ROS levels in A2780/100 cells correlated well with elevated gamma-glutamylcysteine synthetase (gamma-GCS) activity (10 +/- 1.8-fold over A2780 cells). Ectopic overexpression of the gamma-GCS heavy subunit in drug-sensitive cells nearly restored GSH and ROS to pre-treatment levels consequently increased cellular resistance to genotoxic agents (Cbl, Cpl, and IR), while overexpression of gamma-GCS light subunit had no such effects. Thus, in our model system, drug-resistant cells have the inherent ability to maintain increased gamma-GCS activity, reestablish physiological GSH, and cellular redox state and maintain increased cellular resistance to DNA cross-linking agents and IR.

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Acquired alkylating drug resistance of a human ovarian carcinoma cell line is unaffected by altered levels of pro- and anti-apoptotic proteins

Cited by 20 publications

References 27 publications

Gene network analysis of oxidative stress-mediated drug sensitivity in resistant ovarian carcinoma cells

Gene network analysis of oxidative stress-mediated drug sensitivity in resistant ovarian carcinoma cells

In vitro and in vivo activity and cross resistance profiles of novel ruthenium (II) organometallic arene complexes in human ovarian cancer

Enhanced γ‐glutamylcysteine synthetase activity decreases drug‐induced oxidative stress levels and cytotoxicity

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