title: Shikonin regulates HeLa cell death via caspase-3 activation and blockage of DNA synthesis.
abstract: Shikonin, isolated from the plant Lithospermum erythrorhizon Sieb. ET Zucc, inhibited tumor cell growth and induced cell death in various tumor cells, with 50% growth inhibition of human cervical cancer cells, HeLa, at 18.9 +/- 1.1 mumol L-1. Treated with 40 mumol L-1 shikonin, HeLa cells underwent marked apoptotic morphological changes such as a round shape, membrane blebbing and apoptotic bodies derived from the fragmented nuclei. Another hallmark of apoptosis, DNA fragmentation, was observed by gel electrophoresis. Shikonin (10 mumol L-1) significantly blocked the transition from G1 to S phase in the HeLa cell cycle. Pan-caspase inhibitor (Z-VAD-FMK), caspase-3 inhibitor (Z-DEVD-FMK) or caspase-8 inhibitor (Z-IETD-FMK) effectively inhibited shikonin-induced cell death, while caspase-1 inhibitor (Ac-YVAD-CMK) and caspase-9 inhibitor (Z-LEHD-FMK) failed to affect cell death. Caspase-3 activity significantly increased within 12 h after shikonin treatment. Reduced expression of inhibitor of caspase-activated deoxyribonuclease (ICAD) after exposure to shikonin for 12 h suggests the resultant activation of caspase-activated deoxyribonuclease (CAD), leading to apoptosis.
authors.affiliation: Department of Pharmaceutical Science, Heilongjiang University, Harbin 150080, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wu
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Wu
authors.forename: Lin-Hao
authors.initials: LH
authors.lastname: Li
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Tashiro
authors.forename: Satoshi
authors.initials: S
authors.lastname: Onodera
authors.forename: Takashi
authors.initials: T
authors.lastname: Ikejima
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D053148:Caspase 3; D061945:Caspase Inhibitors; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D005434:Flow Cytometry; D006367:HeLa Cells / Q000187:drug effects; D006801:Humans; D020128:Inhibitory Concentration 50; D029684:Lithospermum; D051379:Mice; D009285:Naphthoquinones / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D008517:Phytotherapy
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D061945:Caspase Inhibitors; D009285:Naphthoquinones; C016101:shikonin; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3