Yoshida Yuichi, Wang I-Ching, Yoder Helena M, Davidson Nicholas O, Costa Robert H
Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, College of Medicine, Chicago, Illinois, USA.
Gastroenterology. 2007 Apr;132(4):1420-31. doi: 10.1053/j.gastro.2007.01.036. Epub 2007 Jan 25.
BACKGROUND & AIMS: In this study, we used Forkhead Box m1b (Foxm1b) transgenic mice and conditional Foxm1 knock-out mice to examine the role of Foxm1 in colon cancer development and proliferation.
To induce mouse colorectal cancer, we used a single intraperitoneal injection of azoxymethane (AOM) followed by three 1-week cycles of 2.5% dextran sodium sulfate (DSS) water, each cycle separated by 2 weeks. For these colon tumor studies, we used either Rosa26-Foxm1b transgenic mice that ubiquitously expressed the human Foxm1b complementary DNA or mice in which the Foxm1 fl/fl targeted allele was deleted in colonic epithelial cells using the gut-specific Villin-Cre recombinase transgene (Villin-Cre). Colorectal tumor number and bromodeoxyuridine labeling were determined in Rosa26-Foxm1b mice, Villin-Cre Foxm1-/-, mice and wild-type mice after 12 weeks of AOM/DDS exposure. We also used Foxm1 small interfering RNA-depleted human DLD1 and mouse CT26 colon cancer cell lines to examine DNA replication and anchorage-independent growth.
After 12 weeks of treatment with AOM/DSS, Rosa26 Foxm1b transgenic mice showed an increase in the number and size of colorectal tumors compared with wild-type mice. Likewise, a significant reduction in the development and growth of colorectal tumors was found in Villin-Cre Foxm1-/- mice compared with Foxm1 fl/fl mice after AOM/DSS treatment, which was associated with decreased expression of cyclin A2, cyclin B1, survivin, and T-cell factor 4 genes. Moreover, Foxm1-depleted colon cancer cell lines showed reduced DNA replication and anchorage-independent growth.
These studies suggest that Foxm1 is critical for the proliferation and growth of colorectal cancer.
在本研究中，我们使用叉头框蛋白m1b（Foxm1b）转基因小鼠和条件性Foxm1基因敲除小鼠来研究Foxm1在结肠癌发生和增殖中的作用。
为诱导小鼠结直肠癌，我们单次腹腔注射氧化偶氮甲烷（AOM），随后给予三个为期1周的2.5%葡聚糖硫酸钠（DSS）水溶液周期，每个周期间隔2周。对于这些结肠肿瘤研究，我们使用了普遍表达人Foxm1b互补DNA的Rosa26 - Foxm1b转基因小鼠，或使用肠道特异性维林 - Cre重组酶转基因（Villin - Cre）在结肠上皮细胞中删除Foxm1 fl/fl靶向等位基因的小鼠。在AOM/DDS暴露12周后，测定Rosa26 - Foxm1b小鼠、Villin - Cre Foxm1 - / -小鼠和野生型小鼠的结直肠癌数量和溴脱氧尿苷标记。我们还使用了Foxm1小干扰RNA耗尽的人DLD1和小鼠CT26结肠癌细胞系来检测DNA复制和非锚定依赖性生长。
在AOM/DSS处理12周后，Rosa26 Foxm1b转基因小鼠的结直肠癌数量和大小相较于野生型小鼠有所增加。同样，与AOM/DSS处理后的Foxm1 fl/fl小鼠相比，Villin - Cre Foxm1 - / -小鼠的结直肠癌发生和生长显著减少，这与细胞周期蛋白A2、细胞周期蛋白B1、生存素和T细胞因子4基因的表达降低有关。此外，Foxm1耗尽的结肠癌细胞系显示DNA复制和非锚定依赖性生长减少。
这些研究表明Foxm1对结直肠癌的增殖和生长至关重要。
