Role Of MiR-1-3p Targeted Gene SAMSN1 In Proliferation,Invasion And Metastasis Of Colorectal Cancer Cells

Background:Colorectal cancer(CRC)is one of the common malignant tumors of the digestive tract.Although the morbidity and mortality of CRC have been reduced to a certain extent with the popularization of colonoscopy,the diagnosis and treatment and prognosis of colorectal cancer patients are still not enough.It is still not optimistic.Therefore,the search for CRC tumor markers and the exploration of disease mechanisms are of great significance for the early diagnosis and treatment of CRC patients.Preliminary experiments in this study showed that SAMSN1(SAM domain,SH3 domain and nuclear localization signals 1)was significantly up-regulated in various CRC cell lines.SAMSN1 is mainly expressed in hematopoietic cells,which encodes a cytoplasmic adaptor protein.Previous studies have found that SAMSN1 plays different roles in different types of tumors,but its role in CRC and the regulation of miRNAs remain to be explored.Objective:To investigate whether the abnormal expression of SAMSN1 gene in colorectal cancer affects the biological behavior of tumor and the targeted regulation of miR-13p on SAMSN1.Methods:Western Blot and RT-qPCR were used to detect the expression of SAMSN1 protein and mRNA in cancer tissues and adjacent tissues;The methylation sites of upstream and downstream promoter fragments of SAMSN1 gene in colorectal cancer cell lines were detected by bisulfite sequencing.In vitro,SAMSN1 silencing and overexpression adenovirus packaging vector was constructed.The effects of regulating SAMSN1 expression on the proliferation and colony forming ability of colorectal cancer cells were detected by MTS experiment and clone formation experiment;Transwell chamber experiment was used to evaluate the effect of the change of SAMSN1 expression on the migration and invasion of colon cancer cells.multi database were used to analyze the binding sites between miRNAs and 3’UTRs of SAMSN1;The targeted binding site of miR-1-3p to 3’UTRs of SAMSN1 gene was detected by Dual-luciferase reporter gene experiment.After transfection of candidate miR-1-3p mimic into colorectal cancer cells,Western Blot was used to verify the regulatory effect of miR-1-3p on the protein expression level of SAMSN1 gene.Results:SAMSN1 was up-regulated in colorectal cancer tissues and cell lines.In a variety of colorectal cancer cell lines,there are multiple methylation sites in the upstream promoter fragment of SAMSN1 gene;changing the expression of SAMSN1 gene can affect the proliferation,cloning,migration and invasion of colorectal cancer cells.Dual-luciferase reporter gene assay confirmed that miR-1-3p and SAMSN1 gene 3’UTRs have a targeted binding site;after transfection of miR-1-3p mimic in colorectal cancer cells in vitro,the expression of SAMSN1 gene at the protein level was significant down-regulated.Conclusions:1.In colorectal cancer,methylation sites exist in the upstream promoter region of SAMSN1,which may be an important potential factor affecting tumor development;2.SAMSN1,as an oncogene,can promote the proliferation,clone formation and migration of colorectal cancer cells.and invasion,and its expression is negatively regulated by miR-1-3p.