Over-expression of Bcl-2 against Pteris semipinnata L-induced apoptosis of human colon cancer cells via a NF-kappa B-related pathway.
Ent-11 alpha-hydroxy-15-oxo-kaur-16-en-19-oic-acid (5F), an antitumor component, is a chemical compound isolated from Pteris semipinnata L (PsL), a Chinese traditional herb. We examined whether 5F could affect apoptosis in human colon cancer HT-29 cells, and test whether and how the over-expression of Bcl-2 and Bcl-xL could offset the effect of 5F on cell growth. The result demonstrated that 5F significantly induced apoptosis of HT-29, as shown by MTT assay and DNA fragmentation measurement. Treatment of HT-29 with 5F increased both p38 and iNOS levels, suggesting these two molecules may contribute to the apoptotic effect of 5F. Over-expression of Bcl-2 or Bcl-xL attenuated the increase of p38 and iNOS induced by 5F. The cells with Bcl-2 or Bcl-xL over-expression showed an elevation of nuclear factor kappa B (NF-kappa B) activity, accompanying a significant reduction of 5F-induced apoptosis. Furthermore, inhibition of NF-kappa B by I k B alpha SR, which is a powerful inhibitor of NF-kappa B, restored the ability of 5F to induce apoptosis in the cells transfected with Bcl-2. These data strongly indicated that the apoptotic effect of 5F on HT-29 was closely associated with the activity of NF-kappa B, which was up-regulated by Bcl-2 and Bcl-xL. In conclusion, 5F induced apoptosis in HT-29 cells and this apoptotic effect was associated with the high level of p38 and iNOS expression. The apoptotic effect of 5F could be significantly offset by over-expression of either Bcl-2 or Bcl-xL. Bcl-2, and to the less extent, Bcl-xL, were able to increase the activity of NF-kappa B, which was a known anti-apoptotic molecule in human colon cancer cells.
Chen
G G
GG
Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, NT, Hong Kong. gchen@cuhk.edu.hk
Liang
N-C
NC
Lee
J F Y
JF
Chan
U P F
UP
Wang
S H
SH
Leung
B C S
BC
Leung
K L
KL
D017209:Apoptosis / Q000502:physiology*; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms; D053938:DNA Fragmentation; D004224:Diterpenes / Q000633:toxicity*; D006801:Humans; D008516:Medicine, Chinese Traditional; D016328:NF-kappa B / Q000502:physiology*; D008517:Phytotherapy; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics* / Q000378:metabolism; D032495:Pteris; D051020:bcl-X Protein
C479310:11-hydroxy-15-oxokaur-16-en-19-olic acid; C494811:BCL2L1 protein, human; D004224:Diterpenes; D016328:NF-kappa B; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein