The Role Of Long Non-coding RNA KAK7 In Proliferation And Metastasis In Colorectal Cancer

Objective:The role of long non-coding RNA(lnc RNA)in colorectal cancer(CRC)has not been fully elucidated.To identify the role of lnc RNA-KAT7 in the proliferation and migration of colorectal cancer cells and elucidate the potential mechanism.Methods:140 cases of CRC and matched normal or benign tissue sample were collected from the First People's Hospital of Chen Zhou from 2014 to 2017.Real-time fluorescent quantitative PCR was used to detect the expression of lnc RNA-KAT7 in CRC tissues and cell lines.The chi-square test was used to analyze the correlation between the lnc RNA-KAT7 expression level and age,tumor size,differentiation degree and lymph node metastasis.The lnc RNA-KAT7 expression vector pc DNA-lnc RNA-KAT7 was constructed by using pc DNA3.1 empty vector.In this study,the lnc RNA-KAT7 recombinant plasmid was transiently transfected in the CRC cell line with relatively low expression of lnc RNA-KAT7 using Lip2000 liposome,followed by Neomycin screening and a monoclonal cell strain stably expressing lnc RNA-KAT7 was established.Then in vitro and in vivo experiments such as cell CCK-8 assay,colony formation assay,EDU proliferation assay,scratch assay,transwell assay,nude subcutaneous tumorigenesis assay and western blotting were performed to evaluate the biological roles and potential molecular mechanisms of lnc RNA-KAT7 in the proliferation and migration of cells.Results:The expression level of lnc RNA-KAT7 in CRC tissues was significantly lower than normal or benign tissues,and was also lower in CRC cell lines than in normal intestinal epithelial cells.Low expression of lnc RNA-KAT7 was associated with poor clinicopathologic features in CRC patients,and was negatively correlated with tumor differentiation(p = 0.034),tumor size(p = 0.001)and lymph node metastasis(p = 0.042).In vitro experiments showed that the ability of cell proliferation,migration and invasion was inhibited when the expression of lnc RNA-KAT7 up-regulated in CRC cells.In vivo animal experiment showed that tumor growth was inhibited when lnc RNA-KAT7 was up-regulated in CRC cells.In addition,western blot analysis showed that up-regulation of lnc RNA-KAT7 expression in HCT116 cells increased E-cadherin expression,down-regulated Vimentin expression and MMP-2 expression,attenuated phosphorylation of NF-?B p65.The experimental results support our hypothesis that the expression of lnc RNA-KAT7 can inhibit the malignant phenotype of CRC cells.Conclusion:The lnc RNA-KAT7 is low expressed in CRC tissues and negatively correlates with tumor differentiation,tumor size and lymph node metastasis;lnc RNA-KAT7 can inhibit the proliferation,invasion,migration and tumor growth of CRC cells;lnc RNA-KAT7 may inhibit CRC cell metastasis by inhibiting the phosphorylation of NF-?B and inhibiting the EMT pathway.