Enhanced antitumor potency of polyethylene glycolylated tumor necrosis factor-alpha: a novel polymer-conjugation technique with a reversible amino-protective reagent.
We attempted to develop a novel method for the chemical modification of cytokines with synthetic polymers to increase in vivo therapeutic efficacy. A pH-reversible amino-protective reagent, dimethylmaleic anhydride (DMMAn), was used for polymer conjugation of tumor necrosis factor-alpha (TNF-alpha) with polyethylene glycol (PEG). The novel PEGylated TNF-alpha, PEG-TNF-alpha(+), which was pretreated with DMMAn before PEGylation, had 20% to 40% higher specific activity than PEG-TNF-alpha(-) (not treated with DMMAn) in vitro. Moreover, PEG-TNF-alpha(+) more potently caused tumor necrosis in Meth-A solid tumors in mice than did PEG-TNF-alpha(-). The middle fraction (M) of PEG-TNF-alpha(+), which was of the optimal degree of modification among PEG-TNF-alpha(+)s with different molecular weights, caused the highest degree of tumor hemorrhagic necrosis: 30-fold higher than native TNF-alpha and 2-fold higher than the most potent MPEG-TNF-alpha(-) that also had nearly the same molecular weight. Significantly, improvements in antitumor activity in vivo were more marked than were changes in specific activity. Furthermore, native TNF-alpha caused a dose-dependent body weight loss in mice, whereas no obvious side effects were observed in any PEG-TNF-alpha-treated mice. These results suggest that PEGylation using DMMAn is a useful for clinical cytokine delivery.
Tsunoda
S
S
Department of Biopharmaceutics, School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan.
Ishikawa
T
T
Yamamoto
Y
Y
Kamada
H
H
Koizumi
K
K
Matsui
J
J
Tsutsumi
Y
Y
Hirano
T
T
Mayumi
T
T
D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D010450:Endopeptidases / Q000737:chemistry; D005260:Female; D005354:Fibrosarcoma / Q000188:drug therapy / Q000473:pathology; D006868:Hydrolysis; D007202:Indicators and Reagents; D008299:Maleic Anhydrides / Q000737:chemistry*; D051379:Mice; D008807:Mice, Inbred BALB C; D009368:Neoplasm Transplantation; D011092:Polyethylene Glycols / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology
D000970:Antineoplastic Agents; D007202:Indicators and Reagents; D008299:Maleic Anhydrides; C092033:PEG-modified tumor necrosis factor-alpha; D014409:Tumor Necrosis Factor-alpha; D011092:Polyethylene Glycols; C007474:2,3-dimethylmaleic anhydride; D010450:Endopeptidases