CCL18 downregulates the expression of miR98 in breast cancer cells via N-Ras/c-myc/lin28 pathway / 西安交通大学学报(医学版)

ABSTRACT

Objective To explore whether CCL18 is involved in regulating the expression of miRNAs in breast cancer.Methods The expression profile of miRNAs in the breast cancer cell following CCL18 treatment was determined by miRNAs microarray analysis.Then we performed QRT-PCR and Luciferase Reporter Assay to validate the results from the miRNAs microassay.We used transient transfection to change the expression of miR98 and c-myc in breast cancer cells.We then used QRT-PCR and Western blot to analyze the mechanism by which CCL18 downregulates the expression of miR98 in breast cancer cells.Results miRNAs microarray analysis showed that cells treated with CCL18 differentially expressed 20 miRNAs genes compared with those in the control group. Our QRT-PCR and Luciferase Reporter Assay confirmed the result.The mRNA and protein expressions of C-myc and lin28 were increased after CCL18 stimulation in breast cancer cells.Transfection with c-myc siRNAs rescued the increase of lin28 and loss of miR98 expression caused by CCL18 stimulation.Our results also showed that CCL18 could upregulate the expression of N-Ras at post-transcription level.Conclusion CCL18 downregulates the expression of miR98 via N-Ras/c-myc/lin28 pathway.The downregulated miR98 increases the expression of N-Ras after transfection,which further activates c-myc/lin28 pathway and forms a positive feedback loop.