Eupatoriopicrin-induced lipid peroxidation in liver and tumour tissue of the mouse

Linking tumor cell cytotoxicity to mechanism of drug action: an integrated analysis of gene expression, small-molecule screening and structural databases

An integrated, bioinformatic analysis of three databases comprising tumor-cell-based small molecule screening data, gene expression measurements, and PDB (Protein Data Bank) ligand-target structures has been developed for probing mechanism of drug action (MOA). Clustering analysis of GI50 profiles for the NCI's database of compounds screened across a panel of tumor cells (NCI60) was used to select a subset of unique cytotoxic responses for about 4000 small molecules. Drug-gene-PDB relationships for this test set were examined by correlative analysis of cytotoxic response and differential gene expression profiles within the NCI60 and structural comparisons with known ligand-target crystallographic complexes. A survey of molecular features within these compounds finds thirteen conserved Compound Classes, each class exhibiting chemical features important for interactions with a variety of biological targets. Protein targets for an additional twelve Compound Classes could be directly assigned using drug-protein interactions observed in the crystallographic database. Results from the analysis of constitutive gene expressions established a clear connection between chemo-resistance and overexpression of gene families associated with the extracellular matrix, cytoskeletal organization, and xenobiotic metabolism. Conversely, chemo-sensitivity implicated overexpression of gene families involved in homeostatic functions of nucleic acid repair, aryl hydrocarbon metabolism, heat shock response, proteasome degradation and apoptosis. Correlations between chemo-responsiveness and differential gene expressions identified chemotypes with nonselective (i.e., many) molecular targets from those likely to have selective (i.e., few) molecular targets. Applications of data mining strategies that jointly utilize tumor cell screening, genomic, and structural data are presented for hypotheses generation and identifying novel anticancer candidates.

The effect of topical CCNU(1-(2-chloroethyl)-3 cyclohexyl 1 nitrosurea) treatment on lipid peroxidation of glial tumours transplanted on rat brain

1. The effect of topical CCNU treatment on lipid peroxidation of glial tumors transplanted on rat brain has been investigated in 22 rats. 2. Four groups have been selected as normal brain tissue, normal brain tissue+CCNU, tumour tissue, tumour tissue+CCNU. In these groups malondialdehyde (MDA) levels have been measured as a marker of lipid peroxidation. 3. Lipid peroxidation was high in tumour tissue in respect to controls (P < 0.05). In normal tissues topical CCNU treatment caused increase in lipid peroxidation (P < 0.05). In tumor tissues, topical CCNU decreased lipid peroxidation (P < 0.05). It is concluded that further studies have to be performed in order to determine whether increases in lipid peroxidation on CCNU treated normal brain tissues is a result of the inhibitory effect on cellular defence systems or promotion of free radical production.

Induction of DNA damage in Ehrlich ascites tumour cells by exposure to eupatoriopicrin

The sesquiterpene lactone eupatoriopicrin (EUP) from Eupatorium cannabinum L. has been shown to be cytotoxic in a glutathione (GSH)-dependent way. In order to assess possible DNA damage as a cause for cell death, the study reported was initiated. After 2 hr incubation of Ehrlich ascites tumour cells with EUP, the DNA damage, determined by the use of an alkaline DNA unwinding method, followed by hydroxylapatite column chromatography of degraded DNA, was observed at concentrations only slightly higher than those causing cell death in a clonogenic assay. The amount of EUP, requested to demonstrate DNA damage after a 24-hr post-incubation period lay within the concentration range that was effective in the clonogenic assay (1-10 micrograms/ml). Glutathione (GSH) depletion of the cells to about 99%, by use of buthionine sulphoximine (BSO), enhanced the extent of DNA damage. It is concluded that EUP-induced DNA damage may play a role in the observed cytotoxicity.