Reduced bone marrow toxicity of neocarzinostatin by conjugation with divinyl ether-maleic acid copolymer.
Neocarzinostatin (NCS) was conjugated with divinyl ether-maleic acid anhydride copolymer (pyran copolymer), and its therapeutic effect was compared with that of NCS. The conjugated NCS (pyran-NCS) with a molecular weight of about 23,000, exhibited in vitro cytotoxic activity against eight cell lines and bone marrow cells that was similar to the cytotoxic activity of NCS on a molar basis. Furthermore, both drugs had similar effects against a multidrug-resistant Chinese hamster ovary cell line (CHR C5) and its parent cell line (AUXB1) in vitro. However, pharmacological analysis showed that pyran-NCS had reduced accumulation in the spleen, and most important was three times less hematotoxic in vivo compared with NCS. Also, pyran-NCS had a 1.7-fold higher 50% lethal dose (LD50). Antitumor activity of pyran-NCS and NCS was tested against two different forms of Meth A tumor. In a solid tumor model, pyran-NCS and NCS suppressed tumor growth at three-fourths of the LD50 to 12.8 and 19.0% of the control tumor as evaluated on day 28, respectively (P less than 0.025). In an ascitic tumor model, the percentage increase in the median life span caused by pyran-NCS and NCS was more than 400 and 150% on day 60, respectively. Pyran-NCS is more effective than NCS because the reduced acute toxicity permits an increased drug dosage.
Yamamoto
H
H
Department of Microbiology, Kumamoto University Medical School, Japan.
Miki
T
T
Oda
T
T
Hirano
T
T
Sera
Y
Y
Akagi
M
M
Maeda
H
H
D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects* / Q000627:therapeutic use; D005354:Fibrosarcoma / Q000188:drug therapy; D006412:Hematopoietic Stem Cells / Q000187:drug effects*; D006801:Humans; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D008807:Mice, Inbred BALB C; D011713:Pyran Copolymer / Q000008:administration & dosage; D014407:Tumor Cells, Cultured / Q000187:drug effects; D009353:Zinostatin / Q000008:administration & dosage / Q000009:adverse effects
D011713:Pyran Copolymer; D009353:Zinostatin