Chemopreventive effect of chitosan oligosaccharide against colon carcinogenesis.
Chitosan oligosaccharide (COS, 3 kDa<MW<5 kDa) was tested for colon cancer chemoprevention by measuring the activities of quinine reductase (QR) and glutathione-S-transferase (GST), glutathione (GSH) levels, ornithine decarboxylase (ODC) activity, and cyclooxygenase (COX)-2 expression in HT-29 cells treated with COS. COS induced QR activity in a dose-dependent manner over a concentration range of 0.1-4.0 mg/ml. GST activity was also induced in HT-29 cells treated with COS. In addition, GSH levels were increased 1.3-, 1.4-, and 1.5-fold with COS at 2, 3, and 4 mg/ml, respectively. ODC activity induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) was inhibited by 33% and 39% with 3 and 4 mg/ml of COS, respectively. COS also inhibited the expression of TPA-induced COX-2 protein in HT-29 cells. These results suggest that COS has colon cancer chemopreventive activity by increasing QR and GST activities and GSH levels and by inhibiting ODC activity and COX-2 expression in vitro.
Department of Pharmacology, College of Medicine, Dongguk University, Gyeongju 780-714, Korea.
Kyung-Soo
KS
Nam
Mee-Kyung
MK
Kim
Yun-Hee
YH
Shon
D000970:Antineoplastic Agents / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D002471:Cell Transformation, Neoplastic; D048271:Chitosan / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D003110:Colonic Neoplasms / Q000517:prevention & control*; D019073:HT29 Cells / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D009844:Oligosaccharides / Q000378:metabolism / Q000502:physiology*
D000970:Antineoplastic Agents; D009844:Oligosaccharides; D048271:Chitosan