A Comparison Of The Malignant Behavior Of Asian And Caucasian Colorectal Cancer Cell Lines In Vitro

Objective:The role of NDRG1 in Asians and Caucasian colorectal cancer has been divergent in recent years.This research was designed to investigate the differences of NDRG1 gene between Asian and Caucasian colorectal cancer cell lines,and to compare the differences of roles of NDRG1 gene in the invasion of Asian and Caucasians colorectal cancer cells in vitro.Methods:This study compared the Asian colon cancer cell line SNU-C1 with the Caucasian colon cancer cell line CACO2 in all respects.The cell growth rate was measured by cell counting method.The expression difference of NDRG1 in Asian and Caucasian colorectal cancer cells were 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.Results:The proliferation rate of CACO2 cells was faster than that of SNU-C1 cells(P<0.05).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.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 24h,48h and 72h,However,there wasn't statistically significant at 24h(P= 0.08).There were significant differences between the two groups at 48h and 72h(P= 0.006,P= 0.000).In the migration experiment,the migration of CACO2 cells was lower than SNU-C1 cells at 24h(P= 0.038)but was significantly higher than that of SNU-C1 at 48h and 72h(P= 0.045,P= 0.012).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 has a greater average particle size than CACO2,and SNU-C1 cell surface wrinkles,intracellular subcellular organelles,the number of particles were greater than CACO2.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).The results showed that the MEAN value of NDRG1 protein in CACO2 cells were 36.3 and 86.5 in SNU-C1 cells respectively.The results showed that the MEAN values of NDRG1 DNA contents in CACO2 cells were 45 and 50.2 in SNU-C1 cells respectively.Conclusion:1.The nucleotide sequence of NDRG1 in Asian and Caucasian are the same,but NDRG1 mRNA levels in colorectal cancer are different.2.The invasive and migratory ability of Caucasian CACO2 colorectal cancer cell line was stronger than that of Asian SNU-C1 colorectal cancer cell line under the same conditions.