Huang L, Pardee A B
Division of Cancer Biology, Dana-Farber Cancer Institute, and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
Mol Med. 1999 Nov;5(11):711-20.
Human colon cancers have a high frequency of p53 mutations, and cancer cells expressing mutant p53 tend to be resistant to current chemo- and radiation therapy. It is thus important to find therapeutic agents that can inhibit colon cancer cells with altered p53 status. beta-Lapachone, a novel topoisomerase inhibitor, has been shown to induce cell death in human promyelocytic leukemia and prostate cancer cells through a p53-independent pathway. Here we examined the effects of beta-lapachone on human colon cancer cells.
Several human colon cancer cell lines, SW480, SW620, and DLD1, with mutant or defective p53, were used. The antiproliferative effects of beta-lapachone were assessed by colony formation assays, cell cycle analysis, and apoptosis analysis, including annexin V staining and DNA laddering analysis. The effects on cell cycle and apoptosis regulatory proteins were examined by immunoblotting.
All three cell lines, SW480, SW620, and DLD1, were sensitive to beta-lapachone, with an IC(50) of 2 to 3 microM in colony formation assays, a finding similar to that previously reported for prostate cancer cells. However, these cells were arrested in different stages of S phase. At 24 hr post-treatment, beta-lapachone induced S-, late S/G2-, and early S-phase arrest in SW480, SW620, and DLD1 cells, respectively. The cell cycle alterations induced by beta-lapachone were congruous with changes in cell cycle regulatory proteins such as cyclin A, cyclin B1, cdc2, and cyclin D1. Moreover, beta-lapachone induced apoptosis, as demonstrated by annexin V staining, flow cytometric analysis of DNA content, and DNA laddering analysis. Furthermore, down-regulation of mutant p53 and induction of p27 in SW480 cells, and induction of pro-apoptotic protein Bax in DLD1 cells may be pertinent to the anti-proliferative and apoptotic effects of beta-lapachone on these cells.
beta-Lapachone induced cell cycle arrest and apoptosis in human colon cancer cells through a p53-independent pathway. For human colon cancers, which often contain p53 mutations, beta-lapachone may prove to be a promising anticancer agent that can target cancer cells, especially those with mutant p53.
人类结肠癌中p53突变频率较高，表达突变型p53的癌细胞往往对当前的化疗和放疗具有抗性。因此，找到能够抑制p53状态改变的结肠癌细胞的治疗药物非常重要。β-拉帕醌是一种新型拓扑异构酶抑制剂，已被证明可通过不依赖p53的途径诱导人早幼粒细胞白血病细胞和前列腺癌细胞死亡。在此，我们研究了β-拉帕醌对人结肠癌细胞的影响。
使用了几种具有突变型或缺陷型p53的人结肠癌细胞系，即SW480、SW620和DLD1。通过集落形成试验、细胞周期分析和凋亡分析（包括膜联蛋白V染色和DNA梯状分析）评估β-拉帕醌的抗增殖作用。通过免疫印迹法检测对细胞周期和凋亡调节蛋白的影响。
SW480、SW620和DLD1这三种细胞系均对β-拉帕醌敏感，在集落形成试验中的IC(50)为2至3 microM，这一结果与先前报道的前列腺癌细胞相似。然而，这些细胞在S期的不同阶段被阻滞。处理24小时后，β-拉帕醌分别在SW480、SW620和DLD1细胞中诱导S期、S/G2晚期和S期早期阻滞。β-拉帕醌诱导的细胞周期改变与细胞周期调节蛋白如细胞周期蛋白A、细胞周期蛋白B1、细胞周期蛋白依赖性激酶2（cdc2）和细胞周期蛋白D1的变化一致。此外，如膜联蛋白V染色、DNA含量的流式细胞术分析和DNA梯状分析所示，β-拉帕醌诱导了凋亡。此外，SW480细胞中突变型p53的下调和p27的诱导，以及DLD1细胞中促凋亡蛋白Bax的诱导可能与β-拉帕醌对这些细胞的抗增殖和凋亡作用相关。
β-拉帕醌通过不依赖p53的途径诱导人结肠癌细胞的细胞周期阻滞和凋亡。对于经常含有p53突变的人类结肠癌，β-拉帕醌可能被证明是一种有前景的抗癌药物，可靶向癌细胞，尤其是那些具有突变型p53的癌细胞。
Zotero 插件
