Shikonin induces apoptosis through reactive oxygen species/extracellular signal-regulated kinase pathway in osteosarcoma cells.
Shikonin, a major ingredient in the Chinese traditional herb Lithospermum erythrorhixon, exhibits multiple biological functions including antimicrobial, anti-inflammatory, and antitumor effects. In this study, we delineated the molecular mechanisms of shikonin in the apoptosis of 143B osteosarcoma cells. Shikonin reduced the cell viability of 143B cells in a dose- and time-dependent manner. The IC(50) at 24 h and 48 h for 143B cells was 4.55 and 2.01microM, respectively. A significantly elicited hypodiploid cell population was found in cells treated with 2, 4, and 8microM shikonin for 24 h. Moreover, treatment with shikonin induced reactive oxygen species (ROS) generation, increased extracellular signal-regulated kinase (ERK) phosphorylation, decreased B-cell lymphoma-2 (Bcl2) expression, and was accompanied by poly(ADP-ribose) polymerase (PARP) cleavage. Pretreatment with the antioxidant agent N-acetyl cysteine (NAC) not only reversed shikonin-induced ROS generation but also significantly attenuated the cytotoxic effects of shikonin in 143B cells. Furthermore, NAC attenuated shikonin-induced ERK phosphorylation. Taken together, our results reveal that shikonin increased ROS generation and ERK activation, and reduced Bcl2, which consequently caused the cells to undergo apoptosis. Therefore, shikonin may be a promising chemotherapeutic agent for osteosarcoma treatment.
Chang
I-Chang
IC
Institute of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan.
Huang
Yu-Jen
YJ
Chiang
Tsay-I
TI
Yeh
Chi-Wei
CW
Hsu
Li-Sung
LS
D000111:Acetylcysteine / Q000494:pharmacology; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology / Q000627:therapeutic use; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology* / Q000627:therapeutic use; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000494:pharmacology / Q000627:therapeutic use; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D006801:Humans; D020128:Inhibitory Concentration 50; D009285:Naphthoquinones / Q000494:pharmacology* / Q000627:therapeutic use; D012516:Osteosarcoma / Q000188:drug therapy* / Q000378:metabolism; D010766:Phosphorylation; D008517:Phytotherapy; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D000972:Antineoplastic Agents, Phytogenic; D000975:Antioxidants; D004365:Drugs, Chinese Herbal; D009285:Naphthoquinones; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; C016101:shikonin; D011065:Poly(ADP-ribose) Polymerases; D048049:Extracellular Signal-Regulated MAP Kinases; D000111:Acetylcysteine