| Objectives To investigate the expression of miR-615-3p in gastric cancer tissues and serum,and explore its effects on gastric cancer cell proliferation,migration,invasion and chemotherapeutic drug.Then,determine the target gene of miR-615-3p and its effects on those phenotypes of gastric cancer cell.Methods 1 qRT-PCR was used to analyze miR-615-3p level in clinical gastric cancer tissues(poorly differentiated and well differentiated)and corresponding serum samples;the relationship between the miR-615-3p level in gastric cancer tissues and clinical pathological factors(gender,age,pathological differentiation type and TNM staging)were analyzed;The SPSS software was used to analyze the cut-off point of miR-615-3p levels in the serum of gastric cancer patients and healthy individuals.TheROC curve was drawn to analyze the diagnostic threshold,sensitivity and specificity of miR-615-3p to distinguish gastric cancer and healthy population.2 The miR-615-3p was blocked or overexpressed in MGC-803 cells for 24 hours respectively.Then,CCK-8,transwell migration and invasion assay were used to evaluate the effects of miR-615-3p on the activity,proliferation and invasion of human gastric cells;The protein levels of E-cadherin,N-cadherin and Vimentin were detected by immunocytochemistry and western blot;Different concentrations of oxaliplatin were added at 24 h post-transfection.After 48 h,CCK-8 were used to detect the cell viability.3 qRT-PCR and western blot were used to detect the mRNA and protein expression of miR-615-3p target gene B4GALT1 in gastric cancer tissues and gastric cancer cell lines;The B4GALT1 was knockdowned or overexpressed in MGC-803 cells for 24 hours respectively.Then,CCK-8,transwell migration and invasion assay were used to evaluate the effects of B4GALT1 on the activity,proliferation and invasion of human gastric cells;The protein levels of E-cadherin,N-cadherin and Vimentin were detected by immunocytochemistry and western blot;Different concentrations of oxaliplatin were added at 24 h post-transfection.After 48 h,CCK-8 were used to detect the cell viability.Results 1 The miR-615-3p level in poor differentiated gastric cancer group was significantly higher than that in benign disease tissues group and well differentiated gastric cancer group(P<0.01).There was no significant difference of miR-615-3p level between the well differentiated gastric cancer group and the benign disease tissues group(P>0.05).The miR-615-3p level was associated with pathological type and TNM stage(P<0.05),but not associated with gender and age(P>0.05).In addition,the serum level of miR-615-3p of patients with gastric cancer was significantly higher than that in healthy individuals(P<0.01),and the miR-615-3p level of patients with poor differentiated gastric cancer was significantly higher than that of patients with well differentiated gastric cancer(P<0.01).The area under the receiver operating characteristic curve was 0.803[95% CI(0.707,0.906)] and the difference was statistically significant compared with A = 0.5.The diagnostic threshold for gastric cancer and healthy people was 35.32,the sensitivity was 85.71%,and the specificity was 68.57%.These suggest that miR-615-3p may can be used as a diagnosis of gastric cancer biological indicators with certain accuracy and feasibility.2 Compared with the control group,the activity of the miR-615-3p-blocked cells was significantly decreased(P<0.05,P<0.01).The number of cells passing through the transwell chamber were notably decreased in miR-615-3p-blocked cells(without matrixgel and with matrixgel)(P<0.01).The protein levels of E-cadherin,N-cadherin and Vimentin in miR-615-3p-blocked MGC-803 cells were no significant difference(P>0.05).The results showed that miR-615-3p positively regulates the proliferation,migration and invasion of MGC-803 cells.Compared with the control group,the proliferation abilities of miR-615-3p-blocked MGC-803 cells treated with oxaliplatin for 48 h was significantly weaker(P<0.01).It suggests that miR-615-3p negatively regulates the sensitivity of cells to oxaliplatin.3 The mRNA level of B4GALT1 in poorly differentiated gastric cancer tissues was significantly higher than that in benign disease group(P<0.01).The protein level of B4GALT1 in poorly differentiated gastric cancer was also significantly higher than that in benign disease group(P<0.01).The mRNA level of B4GALT1 in miR-615-3poverexpressed MGC-803 cells was significantly higher than that in control group(P<0.05),and the protein level of B4GALT1 was also significantly higher than that of control group(P<0.01);The mRNA level of B4GALT1 in miR-615-3p-blocked MGC-803 cells was significantly lower than that in control group(P<0.01),and the protein level of B4GALT1 was also markedly lower than that of control group(P<0.01).These results suggest that miR-615-3p positively regulates the expression of B4GALT1 in gastric cancer.Compared with the control group,the activity of the B4GALT1-knockdowned cells was significantly decreased(P<0.05,P<0.01).The number of cells passing through the transwell chamber were notably decreased in B4GALT1-knockdowned group(without matrixgel and with matrixgel)(P<0.01).The protein levels of E-cadherin,N-cadherin and Vimentin in B4GALT1-knockdowned MGC-803 cells were no significant difference(P>0.05).The results indicate that B4GALT1 positively regulates the proliferation,migration and invasion abilities of MGC-803 cells.Compared with the control group,the proliferation abilities of B4GALT1-knockdowned MGC-803 cells treated with oxaliplatin for 48 h was significantly weaker(P<0.05,P<0.01).B4GALT1 negatively regulates the sensitivity of cells to oxaliplatin.Conclusions 1 The expression level of miR-615-3p and its target gene B4GALT1 in gastric cancer were significantly higher than that in benign gastric diseases,The expression level of miR-615-3p and its target gene B4GALT1 in gastric carcinoma were positively correlated with the pathological differentiation type and TNM staging.2 MiR-615-3p maybe promotes the proliferation,migration and invasion of gastric cancer cells and enhances the chemotherapeutic resistance of cells by positively regulating its target gene B4GALT1. |
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