Liu Jian-Jun, Nilsson Ake, Oredsson Stina, Badmaev Vladimir, Zhao Wan-Zhou, Duan Rui-Dong
Cell Biology B, Biomedical Center, B11, Lund University, Sweden.
Carcinogenesis. 2002 Dec;23(12):2087-93. doi: 10.1093/carcin/23.12.2087.
Boswellic acids are the effective components of gum resin of Boswellia serrata, which has anti-inflammatory properties. Recent studies on brain tumors and leukemic cells indicate that boswellic acids may have antiproliferative and apoptotic effects with the mechanisms being not studied in detail. We studied their antiproliferative and apoptotic effects on colon cancer cells and the pathway leading to apoptosis. HT-29 cells were treated with beta-boswellic acid (BA), keto-beta-boswellic acid (K-BA) and acetyl-keto-beta-boswellic acid (AK-BA), respectively. Apoptosis was determined by flow cytometry, by cytoplasmic DNA-histone complex and the activity of caspase-3. The cleavage of poly-(ADP-ribose)-polymerase (PARP) and expression of Fas were examined by western blot. Specific caspase inhibitors, polyclonal Fas antibody, and antagonistic Fas antibody ZB4 were employed to elucidate apoptotic pathways. DNA synthesis and cell viability were examined. Both K-BA and AK-BA increased cytoplasmic DNA-histone complex dose-dependently and increased pre-G(1) peak in flow cytometer analysis, with the effects of AK-BA being stronger than K-BA. BA only increased the formation of DNA-histone complex at a high concentration. K-BA and AK-BA increased caspase-8, caspase-9 and caspase-3 activities accompanied by cleavage of PARP. The effects of AK-BA on formation of cytoplasmic DNA histone and on caspase-3 activation were 3.7- and 3.4-fold, respectively, more effective than those induced by camptothecin. The apoptosis induced by AK-BA was inhibited completely by caspase-3 or caspase-8 inhibitor and partially by caspase-9 inhibitor. ZB4 blocked exogenous Fas ligand-induced apoptosis, but had no effect on AK-BA-induced apoptosis. AK-BA had no significant effect on expression of Fas. Apart from apoptotic effect, these acids also inhibited [(3)H]thymidine incorporation and cell viability to different extent. In conclusion, boswellic acids, particularly AK-BA and K-BA have antiproliferative and apoptotic effects in human HT-29 cells. The apoptotic effect is mediated via a pathway dependent on caspase-8 activation but independent of Fas/FasL interaction.
乳香酸是锯叶乳香树树脂的有效成分，具有抗炎特性。最近对脑肿瘤和白血病细胞的研究表明，乳香酸可能具有抗增殖和凋亡作用，但其机制尚未详细研究。我们研究了它们对结肠癌细胞的抗增殖和凋亡作用以及导致凋亡的途径。分别用β-乳香酸（BA）、酮-β-乳香酸（K-BA）和乙酰基-酮-β-乳香酸（AK-BA）处理HT-29细胞。通过流式细胞术、细胞质DNA-组蛋白复合物和半胱天冬酶-3的活性来确定凋亡。通过蛋白质印迹法检测聚（ADP-核糖）聚合酶（PARP）的裂解和Fas的表达。使用特异性半胱天冬酶抑制剂、多克隆Fas抗体和拮抗Fas抗体ZB4来阐明凋亡途径。检测DNA合成和细胞活力。K-BA和AK-BA均剂量依赖性地增加细胞质DNA-组蛋白复合物，并在流式细胞仪分析中增加G1期前峰，AK-BA的作用比K-BA更强。BA仅在高浓度时增加DNA-组蛋白复合物的形成。K-BA和AK-BA增加半胱天冬酶-8、半胱天冬酶-9和半胱天冬酶-3的活性，并伴有PARP的裂解。AK-BA对细胞质DNA组蛋白形成和半胱天冬酶-3激活的作用分别比喜树碱诱导的作用强3.7倍和3.4倍。AK-BA诱导的凋亡被半胱天冬酶-3或半胱天冬酶-8抑制剂完全抑制，被半胱天冬酶-9抑制剂部分抑制。ZB4阻断外源性Fas配体诱导的凋亡，但对AK-BA诱导的凋亡无影响。AK-BA对Fas的表达无显著影响。除凋亡作用外，这些酸还不同程度地抑制[3H]胸腺嘧啶掺入和细胞活力。总之，乳香酸，尤其是AK-BA和K-BA对人HT-29细胞具有抗增殖和凋亡作用。凋亡作用是通过依赖半胱天冬酶-8激活但独立于Fas/FasL相互作用的途径介导的。
