Beta-catenin antisense treatment decreases beta-catenin expression and tumor growth rate in colon carcinoma xenografts.
Beta-catenin antisense treatment decreases beta-catenin expression and tumor growth rate in colon carcinoma xenografts.
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发表时间：
2001
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通讯作者：
D. W. Green;H. Roh;J. Pippin;J. Drebin
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作者：
D. W. Green;H. Roh;J. Pippin;J. Drebin
背景大肠腺瘤性息肉病(APC)抑癌基因缺失在结直肠癌发生中起重要作用。APC基因产物的一个功能是调节β-连环蛋白，这是一种在细胞黏附中发挥作用的蛋白质，也调节某些转录因子的活性。为了更准确地描述β-catenin信号在结肠癌生长中的作用，我们用针对β-catenin mRNA的反义寡核苷酸(ODN)治疗携带APC突变SW480结肠癌移植瘤的小鼠，并检测了对β-catenin表达和肿瘤生长的影响。方法Balb/C裸鼠皮下注射1×10(6)SW480细胞建立裸鼠移植瘤模型。在一项实验中，肿瘤被允许生长7天，在此之后，动物被随机分成三组，每天接受5、10或20 mg/kg剂量的反义β-连环蛋白ODN、杂合序列β-连环蛋白ODN对照或生理盐水对照7天。肿瘤切除并匀浆，肿瘤裂解物进行凝胶电泳和Western blotting以测定β-连环蛋白的含量。在第二个实验中，荷瘤动物开始每天接受5、10或20 mg/kg剂量的反义β-连环蛋白ODN、杂合序列β-连环蛋白ODN对照或生理盐水对照。通过每周两次测量肿瘤体积来量化肿瘤生长。第三个实验评估了每日推注与持续输注β-连环素反义寡核苷酸(20 mg/kg)的抗肿瘤效果。结果反义β-连环素处理APC基因突变的结直肠癌移植瘤后，β-连环素蛋白表达呈剂量依赖性下调。针对β-连环素的反义治疗对荷瘤小鼠的肿瘤生长也显示出剂量依赖性的抑制作用。持续输注和团注给药的反义寡核苷酸的抗肿瘤效果似乎没有太大差别。结论β-连环蛋白的表达在APC基因突变的结肠癌异种移植瘤的生长过程中起重要作用。针对β-连环蛋白的策略，包括使用反义ODN，可能会在人类结肠癌的治疗中使用。
BACKGROUND Loss of the adenomatous polyposis coli (APC) tumor suppressor gene plays a significant role in colorectal carcinogenesis. One function of the APC gene product is to regulate beta-catenin, a protein that plays a role in cell adhesion and also regulates the activity of certain transcription factors. To more precisely delineate the role of beta-catenin signaling in colon cancer growth, we treated mice bearing APC-mutant SW480 colon cancer xenografts with antisense oligonucleotides (ODNs) directed against beta-catenin mRNA and examined effects on beta-catenin expression and tumor growth. METHODS Balb/C nude mice underwent subcutaneous injection of 1 x 10(6) SW480 cells to establish tumor xenografts. In one experiment, tumors were allowed to grow for 7 days, after which time animals were randomized to undergo daily intraperitoneal injections of either antisense beta-catenin ODN at doses of 5, 10, or 20 mg/kg, scrambled sequence beta-catenin ODN control, or saline control for 7 days. Tumors were excised and homogenized, and tumor lysates subjected to gel electrophoresis and Western blotting for beta-catenin protein quantification. In a second experiment, tumor-bearing animals began receiving daily intraperitoneal injections of either antisense beta-catenin ODN at doses of 5, 10, or 20 mg/kg, scrambled sequence beta-catenin ODN control, or saline control. Tumor growth was quantitated by measuring tumor volumes twice weekly. A third experiment evaluated the antitumor effects of daily bolus dosing versus continuous infusion of beta-catenin antisense ODNs (20 mg/kg). RESULTS Treatment of APC-mutant colorectal carcinoma xenografts with beta-catenin antisense resulted in a dose-dependent down-regulation in beta-catenin protein expression as shown by Western blotting. Treatment of tumor-bearing mice with antisense directed at beta-catenin also demonstrated a dose-dependent inhibition of tumor growth. There appears to be little difference in the antitumor effects of antisense ODNs administered by continuous infusion or bolus dosing schedules. CONCLUSIONS beta-Catenin expression plays a critical role in the tumorigenic growth of APC-mutant colon cancer xenografts. Strategies targeting beta-catenin, including the use of antisense ODNs, may be of use in the treatment of human colon cancer.