In vitro and in vivo antitumor effects of acetylshikonin isolated from Arnebia euchroma (Royle) Johnst (Ruanzicao) cell suspension cultures.
BACKGROUND
Shikonin derivatives have cytotoxic and antitumor effects. This study aims to investigate the antitumor effects of acetylshikonin isolated from a Chinese medicinal herb Arnebia euchroma (Royle) Johnst.


METHODS
The 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the in vitro antitumor effects of acetylshikonin on human lung adenocarcinoma cell line A549, human hepatocellular carcinoma cell line Bel-7402, human breast adenocarcinoma cell line MCF-7 and mouse Lewis lung carcinoma (LLC) cell line. C57BL/6 mice with LLC model were used to study the in vivo antitumor effects of acetylshikonin. The expression of bax, bcl-2 and caspase-3 proteins in LLC tissue was determined with immunohistochemical staining.


RESULTS
In A549, Bel-7402, MCF-7 and LLC cell lines, acetylshikonin inhibited cell growth in a dose-dependent manner. IC50 (means +/- SD) were 5.6 +/- 0.86 microg/ml, 6.82 +/- 1.5 microg/ml, 3.04 +/- 0.44 microg/ml and 2.72 +/- 0.38 microg/ml respectively. Acetylshikonin suppressed tumor growth in C57BL/6 mice with LLC. The inhibition rate of acetylshikonin (2 mg/kg) was 42.85%. Immunohistochemical staining revealed that in the acetylshikonin groups the expression of bax and caspase-3 increased, whereas the expression of bcl-2 decreased, suggesting that acetylshikonin induced tumor cell apoptosis through activating the pro-apoptotic bcl-2 family and caspase-3.


CONCLUSIONS
Acetylshikonin isolated from Arnebia euchroma (Royle) Johnst cell suspension cultures exhibits specific in vivo and in vitro antitumor effects.
Xiong
Wenbi
W
Department of Pharmacology, West China Center for Medical Sciences, Sichuan University, Chengdu, Sichuan, PR China. xiongwbcd@scu.edu.cn
Luo
Gang
G
Zhou
Liming
L
Zeng
Yun
Y
Yang
Wenji
W