NDRG1基因在亚洲人与高加索人大肠癌细胞株中恶性行为的比较

A Comparison of the Malignant Behavior of Asian and Caucasian Colorectal Cancer Cell Lines in Vitro and in Vivo

摘要: 目的：NDRG1在大肠癌中的作用至今仍存在争议，是否与种族有关未见报导，本研究旨在分析NDRG1基因在亚洲人与高加索人大肠癌细胞株中的作用。方法：利用细胞计数法测定细胞生长速度；通过RT-qPCR在mRNA水平比较NDRG1在亚洲人和高加索人大肠癌细胞中的表达；24-Transwell法检测亚洲人和高加索人大肠癌细胞侵袭和迁移能力；流式细胞术检测亚洲人和高加索人大肠癌细胞的大小、细胞周期、DNA含量及NDRG1蛋白含量等；裸鼠背侧皮下移植检测细胞的增殖速度。结果：1) Caco2细胞的体外增殖速度比SNU-C1细胞快，且差异有统计学意义(P < 0.05)。2) 两株细胞所扩增出来的序列均与NDRG1一致，但Caco2与SNU-C1的NDRG1的mRNA水平比值为0.4061，SNU-C1的NDRG1的mRNA水平为Caco2的2.46倍。3) Caco2细胞侵袭能力在24 h、48 h和72 h各时间点均高于SNU-C1，但24 h时间点两组细胞之间差异无统计学意义(P > 0.05)，而48 h和72 h两个时间点两组细胞之间差异有统计学意义(P = 0.006, P = 0.000)。4) Caco2组除24 h组迁移能力比SNU-C1组低之外，48 h和72 h两个时间点迁移能力均高于SNU-C1组，且两组细胞之间差异有统计学意义(P = 0.038, P = 0.045, P = 0.012)。5) 经FSC分析发现Caco2平均体积明显大于SNU-C1，从SSC分析得到SNU-C1细胞表面的皱折度、细胞内亚细胞器、颗粒的数目等均大于Caco2。6) 两种细胞的细胞周期各间期之间差异无统计学意义(P > 0.05)。7) 两株细胞NDRG1蛋白含量为Caco2细胞平均值36.3，SNU-C1细胞平均值86.5。8) 两株细胞NDRG1的DNA含量为Caco2细胞平均值45，SNU-C1细胞平均值50.2。9) 裸鼠背侧皮下移植后Caco2细胞增殖速度快于SNU-C1细胞的，但差异无统计学意义(P > 0.05)。结论：在高加索人大肠癌细胞株Caco2与亚洲人大肠癌细胞株SNU-C1中NDRG1的mRNA水平存在差异，且在体外侵袭与迁移中的作用也存在差异。

Abstract: Objective: The role of NDRG1 in colorectal cancer is still controversial, and whether it is related to ethnicity has not been reported. This study aims to analyze the role of NDRG1 gene in Asian and Caucasian colorectal cancer cell lines. Methods: The cell growth rate was measured by cell counting method. The expression of NDRG1 in Asian and Caucasian colorectal cancer cells was compared by Real-time Quantitative PCR. The difference of invasion and migration ability between Asian and Caucasian colorectal cancer cells was detected by 24-Transwell method. The differences of cell size, cell cycle, DNA content and NDRG1 protein content in Asian and Caucasian colorectal cancer cells were measured by flow cytometry. The cell proliferation rate was detected by dorsal subcutaneous transplantation in nude mice. Results: 1) The proliferation rate of Caco2 cells was faster than that of SNU-C1 cells (P < 0.05) in vitro. 2) The NDRG1 sequences detected by PCR were consistent in Caco2 and SNU-C1 cells. The mRNA expressions of Caco2 and SNU-C1 were detected by qPCR. The ratio of NDRG1 mRNA expression of Caco2 cells to that of SNU-C1 cells was 0.4061. The NDRG1 mRNA expression of SNU-C1 cells was 2.46 times of that of Caco2 cells. 3) Transwell method was used to detect the invasion and migration ability of the two cell lines. The invasion ability of Caco2 cells was higher than that of SNU-C1 cells at 24 h, 48 h and 72 h, However, there wasn't statistically significant at 24 h (P = 0.08). There were significant differences between the two groups at 48 h and 72 h (P = 0.006, P = 0.000). 4) The migration of Caco2 cells was lower than SNU-C1 cells at 24 h (P = 0.038) but was significantly higher than that of SNU-C1 at 48 h and 72 h (P = 0.045, P = 0.012). 5) Two cell sizes were measured by flow cytometry, and FSC analysis found that the average size of Caco2 was bigger than that of SNU-C1. SSC analysis found that SNU-C1 cell surface wrinkles, intracellular subcellular organelles, the number of particles were greater than Caco2. 6) The flow cytometry (FCM) showed no statistically significances in cell cycles (G1 interval P = 0.546, S interval P = 0.119, G2 interval P = 0.071). 7) The MEAN value of NDRG1 protein in Caco2 cells were 36.3 and 86.5 in SNU-C1 cells respectively. 8) The MEAN values of NDRG1 DNA contents in Caco2 cells were 45 and 50.2 in SNU-C1 cells respectively. 9) After dorsal subcutaneous transplantation in nude mice, the proliferation rate of Caco2 cells was faster than that of SNU-C1 cells, but the difference was not statistically significant (P > 0.05). Conclusions: There were differences in the mRNA levels of NDRG1 in Caucasian colorectal cancer cell line Caco2 and Asian colorectal cancer cell line SNU-C1, and there were also differences in the role of NDRG1 in vitro invasion and migration.