In vivo antimelanoma effects of 4-S-cysteaminylphenol, a newly synthesized therapeutic agent specific to melanoma.
Antimelanoma effects of 4-S-cysteaminylphenol (4-S-CAP), which is a newly synthesized melanin precursor, as a chemotherapeutic agent specific to malignant melanoma were determined in an in vivo system using mouse B16 melanoma. The intraperitoneal injection of 4-S-CAP induced a slight delay in the growth period of subcutaneous melanoma of C57BL/6 mice. Survival times of mice after treatment with 4-S-CAP were a little longer than those of control mice (P < 0.05), although all mice died from the local growth of tumours. The viable cell ratio of in vivo subcutaneous tumour cells reduced to 52.8% within 24 h after treatment with 4-S-CAP, but the ratio had recovered to the control level 72 h after treatment (> 90%). Similarly, the proliferating-cell-nuclear-antigen-positive cell ratio of melanotic melanoma had reduced 24 h after treatment and recovered within 72 h after treatment, while 4-S-CAP had no effect on amelanotic tumours. The formation of lung colonies by intravenous inoculation of malignant melanoma cells was compared between mice with intraperitoneal injection of 4-S-CAP and phosphate-buffered saline only. The 4-S-CAP-treated mice had significantly fewer lung colonies compared with the control mice (P < 0.01). The results indicate that the agent, 4-S-CAP, would have a therapeutic effect on malignant melanoma for a short time in vivo and therefore the agent can be effective against a small number of tumour cells, such as lung colonies, although it had little effect on the local tumours.
Kitagawa
M
M
Department of Pathology, Faculty of Medicine, Tokyo Medical and Dental University, Japan.
Nemoto
T
T
Seki
S
S
Ito
S
S
Kasuga
T
T
D000818:Animals; D000951:Antigens, Neoplasm / Q000187:drug effects; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D002453:Cell Cycle / Q000187:drug effects; D003543:Cysteamine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000188:drug therapy; D008297:Male; D008546:Melanoma, Experimental / Q000737:chemistry / Q000188:drug therapy* / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D009687:Nuclear Proteins / Q000187:drug effects; D018809:Proliferating Cell Nuclear Antigen
D000951:Antigens, Neoplasm; D000970:Antineoplastic Agents; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D003543:Cysteamine; C043037:4-S-cysteaminylphenol