Prevention of hepatocarcinogenesis with phosphatidylcholine and menaquinone-4: in vitro and in vivo experiments.
OBJECTIVE
We examined whether phosphatidylcholine inhibited growth of hepatic cancer, as previously shown for menaquinone-4 (vitamin K2).


METHODS
Growth inhibitions by phosphatidylcholine and/or menaquinone-4 and apoptosis induction by phosphatidylcholine were evaluated in vitro using human hepatic cancer cell lines (Hep-3B, Hep-G2, HuH-7, and Alexander). Effects of these agents were then investigated in male Sprague-Dawley rats against hepatocarcinogenesis induced by diethylnitrosamine plus phenobarbital. All rats were killed to examine livers to evaluate inhibitory potential macroscopically and immunohistochemically using an antibody against the marker of carcinogenesis, glutathione S-transferase and apoptotic induction by phosphatidylcholine using TUNEL staining. Blood samples were obtained by cardiac puncture.


RESULTS
In vitro, phosphatidylcholine and menaquinone-4 each inhibited cancer cell growth and phosphatidylcholine induced apoptosis dose-dependently. Moreover, exposure to both synergistically inhibited growth in Hep-3B. In vivo, diets containing phosphatidylcholine with or without menaquinone-4 significantly reduced the number of macroscopic hepatic tumor nodules and the extent of abnormally immunoreactive foci conserving hepatic function on serum examinations compared with controls given only the carcinogens. Moreover, phosphatidylcholine supplementation induced apoptosis on TUNEL staining of liver sections.


CONCLUSIONS
Given together, phosphatidylcholine and menaquinone-4 may exhibit synergy against hepatocarcinogenesis conserving hepatic function that could benefit patients at high risk for hepatocellular carcinoma.
Sakakima
Yoshikazu
Y
Department of Surgery II, Nagoya University School of Medicine, Nagoya, Aichi, Japan. sakakima@med.nagoya-u.ac.jp
Hayakawa
Akemi
A
Nagasaka
Tetsuro
T
Nakao
Akimasa
A
D000818:Animals; D017209:Apoptosis; D006528:Carcinoma, Hepatocellular / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced / Q000187:drug effects* / Q000473:pathology; D004032:Diet; D004052:Diethylnitrosamine / Q000633:toxicity; D004357:Drug Synergism; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D008297:Male; D010634:Phenobarbital / Q000633:toxicity; D010713:Phosphatidylcholines / Q000008:administration & dosage* / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D024482:Vitamin K 2 / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use
D010713:Phosphatidylcholines; D024482:Vitamin K 2; C030814:menatetrenone; D004052:Diethylnitrosamine; D010634:Phenobarbital