Kaempferol induced apoptosis via endoplasmic reticulum stress and mitochondria-dependent pathway in human osteosarcoma U-2 OS cells.
Kaempferol is a natural flavonoid. Previous studies have reported that kaempferol has anti-proliferation activities and induces apoptosis in many cancer cell lines. However, there are no reports on human osteosarcoma. In this study, we investigate the anti-cancer effects and molecular mechanisms of kaempferol in human osteosarcoma cells. Our results demonstrate that kaempferol significantly reduces cell viabilities of U-2 OS, HOB and 143B cells, especially U-2 OS cells in a dose-dependent manner, but exerts low cytotoxicity on human fetal osteoblast progenitor hFOB cells. Comet assay, DAPI staining and DNA gel electrophoresis confirm the effects of DNA damage and apoptosis in U-2 OS cells. Flow cytometry detects the increase of cytoplasmic Ca(2+) levels and the decrease of mitochondria membrane potential. Western blotting and fluorogenic enzymatic assay show that kaempferol treatment influences the time-dependent expression of proteins involved in the endoplasmic reticulum stress pathway and mitochondrial signaling pathway. In addition, pretreating cells with caspase inhibitors, BAPTA or calpeptin before exposure to kaempferol increases cell viabilities. The anti-cancer effects of kaempferol in vivo are evaluated in BALB/c(nu/nu) mice inoculated with U-2 OS cells, and the results indicate inhibition of tumor growth. In conclusion, kaempferol inhibits human osteosarcoma cells in vivo and in vitro.
Huang
Wen-Wen
WW
Department of Biological Science and Technology, China Medical University, Taichung, Taiwan.
Chiu
Yu-Jen
YJ
Fan
Ming-Jen
MJ
Lu
Hsu-Feng
HF
Yeh
Hsiu-Feng
HF
Li
Kun-Hong
KH
Chen
Po-Yuan
PY
Chung
Jing-Gung
JG
Yang
Jai-Sing
JS
D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D017209:Apoptosis; D001859:Bone Neoplasms / Q000188:drug therapy*; D061945:Caspase Inhibitors; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D020552:Comet Assay; D004249:DNA Damage; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006801:Humans; D044949:Kaempferols / Q000494:pharmacology*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D012516:Osteosarcoma / Q000188:drug therapy*; D011897:Random Allocation; D015398:Signal Transduction; D023041:Xenograft Model Antitumor Assays
D016588:Anticarcinogenic Agents; D061945:Caspase Inhibitors; D044949:Kaempferols; C006552:kaempferol