Smith Tracy K, Lund Elizabeth K, Parker Mary L, Clarke Rosemary G, Johnson Ian T
Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK.
Carcinogenesis. 2004 Aug;25(8):1409-15. doi: 10.1093/carcin/bgh149. Epub 2004 Mar 19.
Epidemiological evidence indicates that Brassica vegetables protect against colorectal cancer. Brassicas contain glucosinolates, the breakdown products of which exert antiproliferative effects against cancer cells. We have examined the effects of allyl-isothiocyanate (AITC), a major breakdown product of the glucosinolate sinigrin, on proliferation and death of colorectal cancer cells. HT-29 colorectal cells were exposed to AITC for 24 h and the number of adherent and detached cells determined. Both populations were analysed for cell-cycle characteristics and examined by light and electron microscopy for features of apoptosis and mitosis. Evidence of apoptosis was also determined by flow cytometric analysis of Annexin V staining in the detached population of cells. AITC-treated cells were also stained for alpha-tubulin. Treatment caused cells to round up after 7 h of exposure and subsequently detach. At 24 h these cells were blocked in mitosis. Detached AITC-treated cells showed no signs of apoptosis as assessed by morphological features or by Annexin V staining but they did show evidence of disrupted tubulin. AITC inhibits proliferation of cancer cells by causing mitotic block associated with disruption of alpha-tubulin in a manner analogous to a number of chemotherapeutic agents.
流行病学证据表明，十字花科蔬菜可预防结直肠癌。十字花科植物含有硫代葡萄糖苷，其分解产物对癌细胞具有抗增殖作用。我们研究了硫代葡萄糖苷黑芥子硫苷酸钾的主要分解产物烯丙基异硫氰酸酯（AITC）对结肠癌细胞增殖和死亡的影响。将HT-29结肠癌细胞暴露于AITC 24小时，然后测定贴壁细胞和悬浮细胞的数量。对这两种细胞群体进行细胞周期特征分析，并通过光学显微镜和电子显微镜检查细胞凋亡和有丝分裂的特征。还通过对悬浮细胞群体进行膜联蛋白V染色的流式细胞术分析来确定细胞凋亡的证据。对经AITC处理的细胞也进行α-微管蛋白染色。处理后，细胞在暴露7小时后开始变圆，随后脱落。在24小时时，这些细胞被阻滞在有丝分裂期。经形态学特征或膜联蛋白V染色评估，经AITC处理的悬浮细胞未显示凋亡迹象，但确实显示出微管蛋白破坏的证据。AITC通过引起与α-微管蛋白破坏相关的有丝分裂阻滞来抑制癌细胞的增殖，其作用方式类似于许多化疗药物。
