| Objective:Hepatocellular carcinoma(HCC)is one of the most common malignant tumors of digestive system,ranking fourth and second in incidence rate and mortality in China.There are no obvious clinical symptoms in the early stage of liver cancer,and when relevant symptoms occur,most patients are already in the middle and late stage.Although surgical treatment is available,it is prone to recurrence and has a poor prognosis.Therefore,early detection,diagnosis,and treatment are the best ways to improve the survival rate of patients with primary liver cancer.The early diagnosis of liver cancer mainly relies on imaging,pathology,gene sequencing,and serum tumor markers.However,in the early stage of liver cancer,the first three methods have shortcomings such as low sensitivity,invasive,and heavy economic burden.Serum tumor markers have received increasing attention from researchers.However,traditional tumor markers for liver cancer have insufficient sensitivity and specificity.With the rapid development of molecular biology,cell biology,human genomics,and proteomics,it is urgent to find tumor markers with high sensitivity and specificity for the early diagnosis of liver cancer.As a naturally active polypeptide,human derived polypeptide(DCD)plays an important role in the occurrence and development of tumors,in addition to its significant roles in development,inflammation,tissue repair,and host defense.The expression of DCD is significantly increased in various malignant tumors such as cholangiopancreatic carcinoma,lung cancer,and gastric cancer.In addition,high levels of DCD may predict tumor metastasis progression and poor prognosis.However,the role of DCD in liver cancer remains to be further explored.The research objectives of this study are as follows: 1 To explore the expression of DCD in serum and SK-HEP-1 cells of patients with HCC;2.Identify the effect of DCD on downstream genes or proteins in SK-HEP-1cells;3.Explore the effect of DCD on migration and invasion of SK-HEP-1cells.Methods:1.The serum DCD level was measured by ELISA in 120 patients with HCC and 44 healthy controls.The overexpression plasmid of DCD was transfected into the human HCC cell line SK-HEP-1,and the expression location and correlation of DCD and Nck1 were determined by immunofluorescence co localization.2.Firstly,the plasmid carrying DCD-c DNA and si RNA was used to overexpress and knock out DCD in SK-HEP-1 cells.The expression of DCD,Rac1,Cdc42,Fibronectin,WASP,and Arp2/3 genes and proteins in SK-HEP-1cells transfected with different DCD expression levels were detected using Q-PCR and Western blot,respectively.3.Detect the difference in migration and invasion ability between different SK-HEP-1 cell groups through Transwell experiment.Results:1.The level of DCD in the serum of patients with HCC was significantly higher than that of healthy controls.Both DCD and Nck1 are localized in the cytoplasm and nucleus of SK-HEP-1 cells.DCD c DNA transfection increased Nck1 expression,and DCD si RNA transfection resulted in low levels of DCD and Nck1 expression in the nucleus.2.Overexpression of DCD can significantly increase the expression of Arp2/3,WASP,fibronectin,active Rac1,and Cdc42 proteins in SK-HEP-1cells,while downregulation of DCD can reduce the expression of Arp2/3,WASP,fibronectin,active Rac1,active Rac1/total Rac1,and Cdc42.The transfection of Rac1 in SK-HEP-1 cells significantly increased the levels of active Rac1/total Rac1,WASP,Arp2/3,and Fibronectin,while the co transfection of DCD-si RNA and Rac1 can restore the levels of active Rac1/total Rac1,WASP,Arp2/3,and Fibronectin to the control levels in SK-HEP-1 cells.3.The migration,number of invasive cells,and cell migration rate of SK-HEP-1 cells significantly decreased or decreased under the action of DCD-si RNA,suggesting that downregulation of DCD expression can effectively inhibit the migration and invasion of HCC cells;Rac1transfection can significantly increase the migration and invasion of SKHEP-1 cells.In addition,Rac1 transfection can weaken the inhibitory effect of DCD-si RNA on the migration and invasion of SK-HEP-1 cells.Conclusion:DCD can promote migration and invasion of SK-HEP-1 cells by upregulating the non catalytic regions of Nck1,Rac1,Cdc42,WASP,and Arp2/3,thereby inducing the removal of actin cytoskeleton and fibronectin mediated cell adhesion in SK-HEP-1 cells.The high expression of DCD in hepatoma cells makes it possible to combine with a specific protein domain,regulate different protein levels inside and outside the cell,and promote the continuous occurrence and development of HCC process.Therefore,DCD expression affects the invasion and migration of HCC cells,and has an important impact on the metastasis of HCC,suggesting that DCD may participate in the malignant phenotype of HCC cells. |
