Isoenzyme selective irreversible inhibition of rat and human glutathione S-transferases by ethacrynic acid and two brominated derivatives

Ploemen, J.H.T.M.; Bogaards, J.J.P.; Veldink, Gerrit A.; Ommen, Ben van; Jansen, Dominic; Bladeren, P.J. van

doi:10.1016/0006-2952(93)90137-l

Cited by 35 publications

(17 citation statements)

References 28 publications

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“…Ethacrynic acid (EA), a diuretic drug, has been found to be a glutathione S-transferase (GST) inhibitor (1)(2)(3)(4)(5). Among GSTs, GSTP1-1 catalyzes the conjugation of reduced glutathione with a broad range of substrates, including chemotherapeutic agents, and acts as a detoxification enzyme (6).…”

Section: Introductionmentioning

confidence: 99%

Ethacrynic Acid Butyl-Ester Induces Apoptosis in Leukemia Cells through a Hydrogen Peroxide–Mediated Pathway Independent of GlutathioneS-Transferase P1-1 Inhibition

Wang

Song

et al. 2007

Cancer Research

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Ethacrynic acid (EA), a glutathione S-transferase inhibitor and diuretic agent, inhibits cell growth and induces apoptosis in cancer cells. To improve the activities, the structure of EA has been modified, and it has been shown that EA esters had an increased cell growth inhibitory ability compared with nonesterified analogue. EA butyl-ester (EABE) was synthesized, and its apoptosis induction ability was studied. The efficacy of EABE was compared with that of EA, and the mechanisms of action were studied in HL-60 leukemia cells. EABE exhibited greater cell growth inhibitory and apoptosis induction abilities than did EA. EABE-induced apoptosis in HL-60 cells correlated with increased levels of reactive oxygen species, the death receptor 5 (DR5), and caspase activation and decreased levels of the mitochondrial membrane potential. Pretreatment with antioxidants, either N-acetylcysteine or catalase, completely blocked EABE-induced apoptosis, H 2 O 2 accumulation, and up-regulation of DR5 levels. RG19, a subclone of Raji cells stably transfected with a GSTP expression vector, and K562 cells with high endogenous GSTP1-1 activity were less sensitive to EABE-induced apoptosis. EABE was more rapidly taken up than EA by HL-60 cells as determined by high-performance liquid chromatography (HPLC) measurements of intracellular concentrations. These results suggest that (a) H 2 O 2 production is a mediator of EABE and EAinduced apoptosis; (b) GSTP1-1 plays a negative role in EABE and EA-induced apoptosis; and (c) the activity of EABE is greater than EA due to its more rapid entry into cells. [Cancer Res 2007;67(16):7856-64]

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Section: Introductionmentioning

confidence: 99%

Ethacrynic Acid Butyl-Ester Induces Apoptosis in Leukemia Cells through a Hydrogen Peroxide–Mediated Pathway Independent of GlutathioneS-Transferase P1-1 Inhibition

Wang

Song

et al. 2007

Cancer Research

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“…Dibromodihydroethacrynic acid, an ␣-bromoketone derivative, has demonstrated higher potency but less isozyme selectivity of GST inactivation than ethacrynic acid (10). We designed and synthesized haloenol lactone 1, an ␣-bromoketone precursor, as an inactivator of GST.…”

Section: Resultsmentioning

confidence: 99%

“…The catalytic mechanisms of GSTs are not fully understood but have been the subject of intense investigation (5,6). It has been reported that the sulfhydryl group(s) of GST are reactive to certain electrophilic and oxidizing reagents (7)(8)(9)(10)(11), although site-directed mutagenesis studies showed that these sulfhydryl groups are not required for GST catalysis (12)(13)(14). These enzymes are also responsible for metabolism (deactivation) of many drugs used in the treatment of cancer (15), and it has become evident that overexpression of GST isozymes (particularly the Pi isozyme) plays a significant role in acquired drug resistance of tumor cells (16,17).…”

mentioning

confidence: 99%

Haloenol Lactone Is a New Isozyme-selective and Active Site-directed Inactivator of Glutathione S-Transferase

Zheng

Mitchell

Jones

et al. 1996

Journal of Biological Chemistry

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A haloenol lactone derivative has been synthesized and found to be an isozyme-selective and active sitedirected inactivator of glutathione S-transferase (GST). Preincubation of the haloenol lactone (100 M) with murine Alpha, Mu, or Pi GST isozyme (1.0 M) at pH 6.5, 37°C resulted in time-dependent loss of enzyme activity with highly selective inhibition of the Pi isozyme (t1 ⁄2 , ϳ 2 min). In a separate experiment, a 10-fold excess of the lactone was incubated with GST-Pi isozyme at 37°C for 3 h, followed by dialysis against Nanopure water. GST activity lost upon incubation with the lactone could not be restored by exhaustive dialysis, and only 8% of enzyme activity for the modified GST remained relative to the control that was treated identically except the lactone was omitted from the incubation. Both control and modified GST were characterized using electrospray ionization mass spectrometry. No native GST (23,478 Da) was observed in the spectrum of modified GST. Instead, protein incubated with the lactone exhibited an increase in molecular mass of 230 Da relative to control GST. The lactone (100 M) was incubated with GST Pi isozyme (1.0 M) in the presence of the competitive inhibitor S-hexylglutathione (10 M), which suppressed time-dependent inhibition of GST by the lactone. The results suggest that this haloenol lactone is an irreversible and active site-directed inhibitor of GST that appears to inhibit the enzyme through two consecutive steps of nucleophilic attack.Glutathione S-transferases (GSTs) 1 are a family of enzymes that play a critical role in protection of cells from carcinogenic and cytotoxic xenobiotics by catalyzing the addition of GSH to electrophiles or by donating reducing equivalents to organic hydroperoxides. Four principal classes of cytosolic GST isozymes have been isolated from various eukaryotes and named Alpha, Pi, Mu, and Theta based upon biochemical and immunological properties, amino acid sequences, and x-ray crystal structures (1-3). GSTs exhibit broad and overlapping substrate specificities and can also bind various nonspecific ligands (4). The catalytic mechanisms of GSTs are not fully understood but have been the subject of intense investigation (5, 6). It has been reported that the sulfhydryl group(s) of GST are reactive to certain electrophilic and oxidizing reagents (7-11), although site-directed mutagenesis studies showed that these sulfhydryl groups are not required for GST catalysis (12)(13)(14). These enzymes are also responsible for metabolism (deactivation) of many drugs used in the treatment of cancer (15), and it has become evident that overexpression of GST isozymes (particularly the Pi isozyme) plays a significant role in acquired drug resistance of tumor cells (16,17). In this study, we report a haloenol lactone derivative, compound 1, as a new isozyme-selective and potent active site-directed inactivator of GST. This haloenol lactone derivative can potentially be used as a synergetic agent for cancer chemotherapy, particularly for the treatment of GST overexpres...

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“…Ethacrynic acid is also known to inhibit its metabolizing enzymes which contain a cysteine residue within their active sites [172][173][174][175][176][177][178][179][180]. Depending on the isoenzyme type, the (α-, µ-, π-class) inhibition is reported to be either reversible or irreversible.…”

Section: Inhibitors Containing An Activated Double Bond: Methylene Kementioning

confidence: 97%

Inhibitors of Cysteine Proteases

Vičík¹,

Busemann²,

Baumann³

et al. 2006

CTMC

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The roles of cysteine proteases (CP) as protein degrading and protein processing enzymes both in physiological and pathological processes of mammals are well known. Furthermore, the key roles of CP;s in the life cycles of infectious agents like protozoa and viruses turn them into new important targets for anti-infective drugs. Thus, the effective inhibition of pathologically relevant cysteine proteases has raised increasing interest in drug development. One strategy to create CP inhibitors is the use of electrophilic moieties, which covalently bind to the cysteine residue of the active site of the target protease. In a previous approach we have selected the aziridine-2,3-dicarboxylic acid as weak electrophilic inhibitor fragment. In order to achieve effective enzyme inhibition this electrophile was incorporated into peptidic or peptidomimetic sequences addressing the substrate binding sites of the protease. High selectivity could be obtained with compounds, which bind into both the primed and non-primed substrate binding pockets. In a second approach the alpha,beta-unsaturated ketone of the well-known diuretic drug ethacrynic acid was found to be another appropriate electrophilic moiety. Derivatives thereof turned out to be new non-peptidic CP inhibitors. Results of inhibition assays obtained with these two inhibitor series on various proteases of human, protozoan, and viral origin, theoretical studies to investigate binding modes and inhibition mechanisms, and structure-activity relationships are presented. Furthermore, the results of in vitro assays on respective pathogens as well as the results of first toxicity studies are summarized.

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Isoenzyme selective irreversible inhibition of rat and human glutathione S-transferases by ethacrynic acid and two brominated derivatives

Cited by 35 publications

References 28 publications

Ethacrynic Acid Butyl-Ester Induces Apoptosis in Leukemia Cells through a Hydrogen Peroxide–Mediated Pathway Independent of GlutathioneS-Transferase P1-1 Inhibition

Ethacrynic Acid Butyl-Ester Induces Apoptosis in Leukemia Cells through a Hydrogen Peroxide–Mediated Pathway Independent of GlutathioneS-Transferase P1-1 Inhibition

Haloenol Lactone Is a New Isozyme-selective and Active Site-directed Inactivator of Glutathione S-Transferase

Inhibitors of Cysteine Proteases

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