Preventive effect of green tea catechins on experimental tumor metastasis in senescence-accelerated mice.
Successful avoidance of the immune surveillance system is critical for the development of a blood-borne metastasis. Previous findings suggest that experimental tumor metastasis was enhanced in senescence-accelerated mice prone 10 (SAMP10) due to a reduction in immune surveillance potential with age. In the present study, water containing green tea (GT)-catechins was freely given to SAMP10 mice, and the chemopreventive effect of GT-catechin intake on tumor metastasis was examined. Natural killer cell activity, which is an indicator of immune surveillance potential and is reduced in control mice with age, was maintained by GT-catechin intake. The early accumulation of lung-metastatic K1735M2 melanoma cells in lungs after intravenous injection of the cells and subsequent experimental lung metastasis was investigated in mice given GT-catechins. The accumulation at 6 and 24 h after injection of K1735M2 cells was significantly suppressed, and the number of lung-metastatic colonies was significantly reduced, in comparison with those in control mice. The results suggest that GT-catechin intake prevented the experimental tumor metastasis in aged SAMP10 mice via its inhibition of a reduction in immune surveillance potential with age.
Shimizu
Kosuke
K
Department of Medical Biochemistry and Global COE Program, University of Shizuoka, Shizuoka, Japan.
Kinouchi Shimizu
Naomi
N
Hakamata
Wakako
W
Unno
Keiko
K
Asai
Tomohiro
T
Oku
Naoto
N
D000375:Aging / Q000276:immunology; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology / Q000627:therapeutic use*; D028241:Camellia sinensis / Q000737:chemistry*; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D007157:Immunologic Surveillance / Q000187:drug effects*; D007694:Killer Cells, Natural / Q000378:metabolism; D008175:Lung Neoplasms / Q000188:drug therapy / Q000556:secondary; D008545:Melanoma / Q000188:drug therapy / Q000556:secondary*; D051379:Mice; D008815:Mice, Inbred Strains; D009362:Neoplasm Metastasis / Q000276:immunology / Q000517:prevention & control*; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000188:drug therapy / Q000556:secondary; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*
D000972:Antineoplastic Agents, Phytogenic; D010936:Plant Extracts; D002392:Catechin