Preliminary study on decreasing the expression of FOXP3 with miR-155 to inhibit diffuse large B-cell lymphoma

The aim of the present study was to analyze the association between the transcription factor forkhead box P3 (FOXP3) and diffuse large B-cell lymphoma (DLBCL), and investigate the effect of microRNA-155 (miR-155) on the generation and development of FOXP3 in DLBCL. The reverse transcription-quantitative polymerase chain reaction (RT-qPCR) technique was used to determine the expression of FOXP3 in the human DLBCL cell lines Ly1, Ly8 and Ly10, and in normal B cells. An immunohistochemical method was used to determine FOXP3 expression in 60 DLBCL tumor and adjacent tissues, and a retrospective analysis of FOXP3 expression in tumor tissues and clinical data was performed. The lentiviral transfection technique was used to silence the miR-155 gene in mouse A20 cells to analyze the influence of miR-155 on FOXP3 in DLBCL. The A20 cell line with a silenced miR-155 gene was used to perform a tumorigenicity assay in BALB/c mice, and to compare the tumorigenicity rate and the tumor growth rate. The results identified that the expression of the transcription factor FOXP3 in the human DLBCL cell lines was increased compared with normal B cells; FOXP3 in human DLBCL tumor issues was increased compared with the tumor-adjacent tissue, and the increased expression of FOXP3 was identified as an indicator of poor prognosis of patients with DLBCL in the middle and late period; FOXP3 level decreased subsequent to silencing miR-155 in A20 cells; A20 cells with the low-expression miR-155 gene were used to determine the tumorigenicity in BALB/c mice and it was identified that the tumorigenicity of the low-expression miR-155 gene group was decreased compared with the untransfected group. Therefore, miR-155 may be a regulatory factor of FOXP3, and miR-155 may be associated with the metastasis and prognosis of patients with DLBCL.