The plant alkaloid cryptolepine induces p21WAF1/CIP1 and cell cycle arrest in a human osteosarcoma cell line.
The plant alkaloid cryptolepine induces p21WAF1/CIP1 and cell cycle arrest in a human osteosarcoma cell line.
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DOI：
10.3892/ijo.31.4.915
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发表时间：
2007-10
影响因子：
5.2
通讯作者：
T. Matsui;Y. Sowa;H. Murata;K. Takagi;Ryoko Nakanishi;S. Aoki;M. Yoshikawa;Motomasa Kobayashi;T. Sakabe;T. Kubo;T. Sakai
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文献类型：
--
作者：
T. Matsui;Y. Sowa;H. Murata;K. Takagi;Ryoko Nakanishi;S. Aoki;M. Yoshikawa;Motomasa Kobayashi;T. Sakabe;T. Kubo;T. Sakai
我们先前建立了一种生物测定方法，以筛选以p53非依赖性方式激活p21（WAF 1/CIP 1）启动子活性的化合物，p21是一种有效的细胞周期蛋白依赖性激酶抑制剂。作为p21（WAF 1/CIP 1）启动子活性的激活剂，我们从传统的阿育吠陀药用植物Sida cordifolia中分离出一种吲哚喹啉生物碱--cryptolepine（CLP：5-甲基吲哚（2，3b）-quiniine）。我们发现CLP诱导p53突变的人骨肉瘤MG 63细胞中p21（WAF 1/CIP 1）的表达并导致生长停滞。4 μ mol CLP可完全抑制MG 63细胞的生长，并使其阻滞于G2/M期。CLP在mRNA和蛋白水平上调p21（WAF 1/CIP 1）的表达，且呈剂量依赖性。使用几种突变型p21（WAF 1/CIP 1）启动子构建体，我们发现CLP响应元件是相对于p21（WAF 1/CIP 1）启动子的转录起始位点的-82位的Sp1位点。这些结果表明，CLP通过激活p21（WAF 1/CIP 1）启动子，通过特定的Sp1位点，以p53非依赖性的方式阻止MG 63细胞的生长。此外，CLP介导的细胞周期阻滞减少了敲除p21（WAF 1/CIP 1）基因在人结肠癌HCT 116细胞，表明CLP的细胞周期阻滞至少部分是通过诱导p21（WAF 1/CIP 1）表达介导的。尽管我们需要进一步研究体内化疗效果，但这些结果表明CLP可能是治疗骨肉瘤的合适化疗药物。
We previously established a bioassay method to screen for compounds that activate the promoter activity of p21(WAF1/CIP1), a potent inhibitor of cyclin-dependent kinases, in a p53-independent manner. As an activator of p21(WAF1/CIP1) promoter activity, we isolated cryptolepine (CLP: 5-methyl indolo (2,3b)-quiniine), an indoloquinoline alkaloid, from the traditional Ayurvedic medicinal plant Sida cordifolia. We show here that CLP induces the expression of p21(WAF1/CIP1) with growth arrest in p53-mutated human osteosarcoma MG63 cells. Four micromolar of CLP completely inhibited the growth of MG63 cells and caused G2/M-phase arrest. CLP up-regulated the expression of p21(WAF1/CIP1) at both mRNA and protein levels in a dose-dependent manner. Using several mutant p21(WAF1/CIP1) promoter constructs, we found that the CLP-responsive element is an Sp1 site at -82 relative to the transcription start site of the p21(WAF1/CIP1) promoter. These findings suggest that CLP arrests the growth of MG63 cells by activating the p21(WAF1/CIP1) promoter through the specific Sp1 site in a p53-independent manner. In addition, CLP-mediated cell cycle arrest was reduced by the knockout of the p21(WAF1/CIP1) gene in human colon cancer HCT116 cells, suggesting that the cell cycle arrest by CLP was at least partially mediated through the induction of p21(WAF1/CIP1) expression. Although we need further study of chemotherapeutic effect in vivo, these results raise the possibility that CLP might be a suitable chemotherapeutic agent for treatment of osteosarcoma.