Diquat and endothall: Their fates in the environment

Simsiman, G. V.; Daniel, T. C.; Chesters, G.

doi:10.1007/978-1-4613-9404-4_11

Cited by 31 publications

(16 citation statements)

References 96 publications

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“…Endothall is readily soluble in water, and its potassium salt is currently used as a herbicide, especially in aquatic ecosystems. 137 The potential antitumor properties of endothall has only been described by Blazsek 138 and Thiery 139 and its mitotic defects can be understood from its inhibition of PP2A. Significantly, in vitro, endothall inhibited the growth of primary hepatocellular carcinoma cell lines more than that of normal hepatocytes or colon carcinomas.…”

Section: A Cantharidin and Its Derivativesmentioning

confidence: 97%

Platinum‐based anticancer agents: Innovative design strategies and biological perspectives

Au-Yeung

2003

Medicinal Research Reviews

304

185

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The impact of cisplatin on cancer chemotherapy cannot be denied. Over the past 20 years, much effort has been dedicated to discover new platinum-based anticancer agents that are superior to cisplatin or its analogue, carboplatin. Most structural modifications are based on changing one or both of the ligand types coordinated to platinum. Altering the leaving group can influence tissue and intracellular distribution of the drug, whereas the carrier ligand usually determines the structure of adducts formed with DNA. DNA-Pt adducts produced by cisplatin and many of its classical analogues are almost identical, and would explain their similar patterns of tumor sensitivity and susceptibility to resistance. Recently some highly innovative design strategies have emerged, aimed at overcoming platinum resistance and/or to introduce novel mechanisms of antitumor action. Platinum compounds bearing the 1,2-diaminocyclohexane carrier ligand; and those of multinuclear Pt complexes giving rise to radically different DNA-Pt adducts, have resulted in novel anticancer agents capable of circumventing cisplatin resistance. Other strategies have focused on integrating biologically active ligands with platinum moieties intended to selectively localizing the anticancer properties. With the rapid advance in molecular biology, combined with innovation, it is possible new Pt-based anticancer agents will materialize in the near future.

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Section: A Cantharidin and Its Derivativesmentioning

confidence: 97%

Platinum‐based anticancer agents: Innovative design strategies and biological perspectives

Au-Yeung

2003

Medicinal Research Reviews

304

185

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“…Biotransformation is the dominant process controlling the persistence of endothall in aquatic environments [12][13][14][15]. The DSPG values ranged from 1.74 x lop5 to 1.96 x Biotransformation.…”

Section: Laboratory Parameterizationmentioning

confidence: 99%

Validation trial of predictive fate models using an aquatic herbicide (endothall)

Reinert

Rodgers

1986

Enviro Toxic and Chemistry

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Environmental risk assessment of pesticides in aquatic environments requires predictions of their persistence and compartmentalization. A strategy for developing confidence in predictive fate models, such as the Exposure Analysis Modeling System (EXAMS) and the Simplified Lake and Stream Analysis model (SLSA), is to test the models using carefully chosen chemicals in semi-controlled and field situations. For example, endothall, a relatively water-soluble aquatic herbicide, essentially has a sole fate process, biotransformation. This dicarboxylic acid was used to test the predictive capabilities of EXAMS and SLSA and to identify sources of variance in those predictions. The models were parameterized using laboratory, experimental pool and field measurements. Persistence and compartmentalization of endothall in the water, sediments and aquatic plants (Eurasian watermilfoil-Myriophyllum spicatum L.) contained in experimental pools were measured using gas chromatography. Both EXAMS and SLSA predicted aqueous compartment half-lives ranging from 7.3 to 7.8 d, whereas an aqueous half-life of 4 d was observed in the experimental pools. Endothall was introduced to areas within Pat Mayse Lake, a 2,400-ha reservoir in north central Texas, as part of an aquatic plant management program for M. spicatum. Concentrations of endothall were below detection limits (0.002 mg L water, 0.01 mg kg sediment) in 2 to 3 d and in 4 d in the water and sediment compartments, respectively. EXAMS and SLSA predicted half-lives ranging from 3 to 6 d in the water column. Observed aqueous half-lives ranged from 0.1 to 0.23 d. Horizontal dispersion and dilution contributed significantly to the dissipation of endothall at these sites. Predicted concentrations of endothall in sediment were similar to the measured concentrations. This study is one validation trial of EXAMS and SLSA in which the models were not considered validated.

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“…This is importance for several reasons. First, endothall has been used as a defoliant herbicide, 36 but its anticancer potential has only now been described (see Blazsek et al 60 and this study). Secondly, the basic characteristics of endothall indicate that it could be an ideal pharmacologic agent for treating chronic diseases.…”

Section: Discussionmentioning

confidence: 94%

“…Endothall is readily soluble in water, and its potassium salt is currently used as a herbicide, especially in aquatic ecosystems. 36 However, there is as yet no evidence that endothall is useful in cancer chemotherapy.…”

mentioning

confidence: 99%

Hepatocellular Carcinoma Cell Lines From Diethylnitrosamine Phenobarbital–Treated Rats. Characterization and Sensitivity to Endothall, A Protein Serine/Threonine Phosphatase–2A Inhibitor

et al. 1999

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Primary hepatocellular carcinoma (HCC) is probably one of the most common fatal forms of liver cancer. We have established permanent cell lines from diethylnitrosamine/ phenobarbital induced primary rat liver carcinomas to study new anticancer therapies. The rat hepatocellular carcinoma cell lines (HR-2, HR-3, and HR-4) have been maintained in culture for over 3 years. They form tumors when transplanted sc or im into young syngeneic rats. Immunocytology (␣-fetoprotein, albumin), biochemical (␥-glutamyl transferase), and histochemical (glycogen) marker studies and electron microscopy (biliary canaliculi) showed unique, stable differentiation patterns in these tumor lines. They overproduced the c-met protooncogene product and formed colonies spontaneously in semisolid culture with high cloning efficiency (HR-2: 50%-80%, HR-3: 35%-50% and HR-4: 50%-65%). The sensitivity of these cell lines to inhibitors of protein ser/thr phosphatase-2A (PP2A), a key enzyme in the control of G1/S and G2/M cell cycle phase transitions in eukaryotes, was studied in vitro. The specific, weak inhibitor of PP2A, endothall, caused dose-and timedependent cytostasis specifically in G2/M. The cells died later by apoptosis, which was confirmed by cytology (annexin V-FITC labeling, propidium iodide painting of apoptotic bodies) and by fluorescent activated cell sorter (FACS) DNA measurements. The HR-2, HR-3, HR-4, and Zajdela hepatocellular carcinomas were most sensitive to endothall (IC 50 of 1.7, 1.2, 0.9, and 1.7 g/mL), whereas newborn rat hepatocytes growing exponentially in primary culture (IC 50 ‫؍‬ 6.2 g/mL), rat DHD/K12 colon carcinoma cells (IC 50 ‫؍‬ 3.6 g/mL), or human HT-29 colon carcinoma cells (IC 50 ‫؍‬ 4.9 g/mL) were less sensitive. Thus, endothall inhibits preferentially HCC growth and these new rat hepatocellular carcinoma lines may be useful for further biochemical and pharmacological studies on PP2A inhibitors, and for testing new forms of treatment of hepatic cell carcinomas.

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Diquat and endothall: Their fates in the environment

Cited by 31 publications

References 96 publications

Platinum‐based anticancer agents: Innovative design strategies and biological perspectives

Platinum‐based anticancer agents: Innovative design strategies and biological perspectives

Validation trial of predictive fate models using an aquatic herbicide (endothall)

Hepatocellular Carcinoma Cell Lines From Diethylnitrosamine Phenobarbital–Treated Rats. Characterization and Sensitivity to Endothall, A Protein Serine/Threonine Phosphatase–2A Inhibitor

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