The Effect Of SMYD3 Gene Knockout Mediated By CRISPR/Cas9 On Human Lung Cancer Cells

CRISPR/Cas9 gene editing system is a new type of gene editing technology developed based on the immune mechanism of bacteria and archaea resisting the invasion of exogenous nucleic acid,carry out the adaptive immune responses against invading genetic elements (virus or plasmid) by using RNAs to guide site-specific cleavage of genetic material. CRISPR/Cas9 technology has characters of high targeting efficacy and a robust of sequence-specificity. It has a broad range of applications in perform site-directed genome modification. SET and MYND domain-containing protein 3 (SMYD3) is a histone H3-K4 methylase, playing an improtant role in the carcinogenesis and development of many malignant tumors in humans, such as hepatocellular carcinoma, colon cancer, breast cancer and cholangiocarcinoma. SMYD3 is able to alter the histone methylation status in the promoter region of its downstream genes, regulating gene expression and cell proliferation, migration and apoptosis.In this study, the expression of SMYD3 mRNA was detected in human lung cancer cells, and its effect on malignant phenotype of carcinoma cells were studied after knocked out SMYD3 gene using CRISPR/Cas9 technology. The results showed that the expression level of SMYD3 detected by real-time quantitative PCR in the lung cancer cell line A549 were similar to that of the lung epithelial cells, but lower than that of the lung cancer cell line H460. In addition, to knock down of SMYD3 in H460 and A549 cell lines, CRISPR/Cas9 vector was constructed, after transfected by liposome method, the positive cells were sorted by LabQuanta Flow Cytometer Cell. The results showed that the expression of SMYD3 was inhibited in both of H460 and A549 cell lines with significant difference. We tested the effect of the ability of cell proliferation, cell migration, cell invasive and anchorage-independent growth after knocked down the SMYD3 by CCK-8 detection and the Traswell method, and the results revealed that after knocked down of SMYD3, the malignant phenotypes were inhibited in H460 and A549 cell lines. In conculusion, SMYD3 gene play roles on cell proliferation, cell migration and cell invasive in lung cancer cell, it implies that SMYD3 gene maybe a target gene for lung cancer treatment.