sodium-chlorate and Neoplasms

Cationic antimicrobial peptides (CAPs) with antitumor activity constitute a promising group of novel anticancer agents. These peptides induce lysis of cancer cells through interactions with the plasma membrane. It is not known which cancer cell membrane components influence their susceptibility to CAPs. We have previously shown that CAPs interact with the two glycosaminoglycans (GAGs), heparan sulfate (HS) and chondroitin sulfate (CS), which are present on the surface of most cells. The purpose of this study was to investigate the role of the two GAGs in the cytotoxic activity of CAPs.. Various cell lines, expressing different levels of cell surface GAGs, were exposed to bovine lactoferricin (LfcinB) and the designer peptide, KW5. The cytotoxic effect of the peptides was investigated by use of the colorimetric MTT viability assay. The cytotoxic effect on wild type CHO cells, expressing normal amounts of GAGs on the cell surface, and the mutant pgsA-745, that has no expression of GAGs on the cell surface, was also investigated.. We show that cells not expressing HS were more susceptible to CAPs than cells expressing HS at the cell surface. Further, exogenously added heparin inhibited the cytotoxic effect of the peptides. Chondroitin sulfate had no effect on the cytotoxic activity of KW5 and only minor effects on LfcinB cytotoxicity.. Our results show for the first time that negatively charged molecules at the surface of cancer cells inhibit the cytotoxic activity of CAPs. Our results indicate that HS at the surface of cancer cells sequesters CAPs away from the phospholipid bilayer and thereby impede their ability to induce cytolysis.

Topics: Animals; Cattle; Cell Line, Tumor; Chlorates; CHO Cells; Cricetinae; Cricetulus; Drug Synergism; Heparin; Heparitin Sulfate; HT29 Cells; Humans; Lactoferrin; Lymphoma; Neoplasms; Peptide Fragments; Protein Structure, Secondary

Sodium chlorate occurs when drinking water is disinfected by chlorine dioxide. We studied the effects of sodium chlorate in rats and mice to identify potential toxic or carcinogenic hazards to humans.. We gave groups of male and female rats drinking water containing 125, 1,000, or 2,000 milligrams (mg) of sodium chlorate per liter (L) of water for two years. Male and female mice received 500, 1,000, or 2,000 mg/L. Other groups of animals received plain tap water and served as the control groups. At the end of the study, tissues from more than 40 sites were examined for every animal.. Male and female rats receiving sodium chlorate had higher rates of follicular cell hypertrophy of the thyroid gland, and the groups receiving 2,000 mg/L had higher rates of thyroid gland cancer, compared with the control groups. Female mice exposed to sodium chlorate had a few pancreatic islet cell tumors.. We conclude that sodium chlorate caused some thyroid gland neoplasms in male and female rats. The pancreatic islet cell tumors in female mice may have been related to sodium chlorate exposure.

Topics: Administration, Oral; Animals; Body Weight; Bone Marrow Diseases; Carcinogenicity Tests; Carcinogens; Chlorates; Dose-Response Relationship, Drug; Female; Hyperplasia; Male; Mice; Mice, Inbred Strains; Molecular Conformation; Neoplasms; Rats; Rats, Inbred F344; Risk Assessment; Survival Analysis; Thyroid Diseases; Thyroid Gland; Toxicity Tests, Acute; Toxicity Tests, Chronic; Water Supply