Prophylactic effect of Korean mistletoe (Viscum album coloratum) extract on tumor metastasis is mediated by enhancement of NK cell activity.
We here demonstrated the prophylactic effect of an extract (KM-110) from Viscum album coloratum, a Korean mistletoe, on tumor metastasis produced by highly metastatic tumor cells, colon 26-M3.1 carcinoma, B16-BL6 melanoma and L5178Y-ML25 lymphoma cells, using experimental models in mice. Intravenous (i.v.) administration of KM-110 (100 microg/mouse) 2 days before tumor inoculation significantly inhibited lung metastasis of B16-BL6 and colon 26-M3.1 cells, and liver and spleen metastasis of L5178Y-ML25 cells. The prophylactic effect of KM-110 on tumor metastasis was evident with various administration routes, i.e. subcutaneous, oral, intranasal as well as i.v., and was dependent upon the dose of KM-110 administered. Furthermore, mice given KM-110 (100 microg) 2 days before tumor inoculation showed significantly prolonged survival rates compared with the untreated mice. In a time course analysis of NK activity, i.v. administration of KM-110 (100 microg) significantly augmented NK cytotoxicity to Yac-a tumor cells from 1 to 3 days after KM-110 treatment. Furthermore, depletion NK cells by injection of rabbit anti-asialo GM1 serum completely abolished the inhibitory effect of KM-110 on lung metastasis of colon 26-M3.1 cells. These results suggest that KM-110 possesses immunopotentiating activity which enhances the host defense system against tumors, and that its prophylactic effect on tumor metastasis is mediated by NK cell activation.
Yoon
T J
TJ
Animal Resources Research Center, College of Animal Husbandry, Kon-Kuk University, Seoul, Korea.
Yoo
Y C
YC
Kang
T B
TB
Baek
Y J
YJ
Huh
C S
CS
Song
S K
SK
Lee
K H
KH
Azuma
I
I
Kim
J B
JB
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural / Q000187:drug effects / Q000502:physiology*; D037102:Lectins / Q000627:therapeutic use*; D008113:Liver Neoplasms / Q000517:prevention & control / Q000556:secondary; D008175:Lung Neoplasms / Q000517:prevention & control / Q000556:secondary; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D014784:Mistletoe / Q000737:chemistry*; D009362:Neoplasm Metastasis / Q000473:pathology / Q000517:prevention & control*; D009368:Neoplasm Transplantation; D010627:Phenethylamines / Q000627:therapeutic use*; D008517:Phytotherapy; D010936:Plant Extracts / Q000627:therapeutic use; D037121:Plant Lectins; D010946:Plants, Medicinal; D013160:Splenic Neoplasms / Q000517:prevention & control / Q000556:secondary; D014407:Tumor Cells, Cultured; D014439:Tyramine / Q000627:therapeutic use*
D000972:Antineoplastic Agents, Phytogenic; D037102:Lectins; D010627:Phenethylamines; D010936:Plant Extracts; D037121:Plant Lectins; D014439:Tyramine