Chen G G, Liang N-C, Lee J F Y, Chan U P F, Wang S H, Leung B C S, Leung K L
Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, NT, Hong Kong.
Apoptosis. 2004 Sep;9(5):619-27. doi: 10.1023/B:APPT.0000038041.57782.84.
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.
对映-11α-羟基-15-氧代-贝壳杉-16-烯-19-酸（5F）是一种抗肿瘤成分，是从中国传统草药半边旗（PsL）中分离出的一种化合物。我们研究了5F是否会影响人结肠癌HT-29细胞的凋亡，并测试Bcl-2和Bcl-xL的过表达能否以及如何抵消5F对细胞生长的影响。结果表明，如MTT法和DNA片段化检测所示，5F显著诱导HT-29细胞凋亡。用5F处理HT-29细胞可增加p38和诱导型一氧化氮合酶（iNOS）的水平，表明这两种分子可能参与了5F的凋亡作用。Bcl-2或Bcl-xL的过表达减弱了5F诱导的p38和iNOS的增加。过表达Bcl-2或Bcl-xL的细胞显示核因子κB（NF-κB）活性升高，同时5F诱导的凋亡显著减少。此外，用IκBαSR抑制NF-κB（一种强大的NF-κB抑制剂）可恢复5F诱导转染Bcl-2细胞凋亡的能力。这些数据强烈表明，5F对HT-29细胞的凋亡作用与NF-κB的活性密切相关，而NF-κB的活性由Bcl-2和Bcl-xL上调。总之，5F诱导HT-29细胞凋亡，这种凋亡作用与p38和iNOS的高表达水平有关。5F的凋亡作用可被Bcl-2或Bcl-xL的过表达显著抵消。Bcl-2以及程度较轻的Bcl-xL能够增加NF-κB的活性，NF-κB是人类结肠癌细胞中一种已知的抗凋亡分子。
