In Vitro Study The Effect Of Invasion And Metastasis Ability In FAK Silenced Thyroid Cancer Cells

Background and ObjectivesThyroid cancer is common malignant tumor of head and neck, incidence of the cases increased gradually. Despite recent advancements in diagnosis and treatment, the long-term survival rate has undergone little improvement in the recent years, which is attributed mainly to tumor invasion and metastasis. Tumor metastasis is a complex process.The tumor cell invade and break through the extracellular matrix is the basic step,then enter blood,reach distant organs through the blood,break blood vessels into the target organ for settlement,proliferation.Loss of adhesion of the malignant cells to the extracellular matrix is one of the fundamental pathways that promote tumor cell migration, invasion, and metastasis. Evidences have suggested that as an important intracellular signaling molecule,focal adhesion kinase(FAK) mediate intracellular signaling network of cross-linking, play a key role in cells'movement and invasion.The expression of FAK in primary cancer and metastasis cancer are more than in normal thyroid tissues.Therefore, interventing the expression of FAK could provide a new way to treat the thyroid cancer.RNA interference(RNAi) has a strong role in inhibition of the targeted gene,which is more than antisense oligonucleotides.RNAi is considered as a landmark after the PCR method of genetic engineering.This study was to evaluate the ability of proliferation,invasion and metastasis in transfected SW579 cells after FAK silenced by RNA interference and provide evidence to a new therapeutic method.Methods1. Construct FAK RNAi lentivirus vector, transfect thyroid cancer SW579 cells in vitro to establish a stable transfected cell line. Cell transfection efficiency was detected by GFP. 2. To use MTT assay to detect the proliferative activity of SW579 before and after the interference with FAK expression.The situation of suppressed FAK are identified with Western blot.3. Prepare Transwell chambers to detect the effect of FAK silencing on invasion and metastasis of SW579 Cells.Results1. To construct RNAi lentiviral vector with targeting FAK successfully, obtain transfection SW579 Cells.2. Compared with the untreated group and group of cells in negative control group, the interference group cells'survival rate were significantly decreased (P <0.05), but the normal group and the negative control group had no significant difference (P>0.05). And FAK expressions in the interference group were significantly reduced than other groups.3. Invasion and metastasis in vitro experiments: compared with the normal group and negative control group cells, the ability of invasion and metastasis had decreased significantly (P<0.05) in the interference group cells, while the normal group and negative control group had no significant difference (P>0.05).Conclusions1. Successfully construct FAK RNAi lentivirus vector could stably transfected thyroid cancer cells SW579.2. FAK RNAi can effectively inhibit the proliferation activity of transfected SW579 cells.3. Silencing FAK gene expression can significantly inhibit the capacity of invasion and metastasis of SW579 cells.