TFEB promotes BCL-2 expression by upregulating its promoter activity in the t(6;11) translocation renal cell...

t(6;11) translocation renal cell carcinoma (RCC) is classified as a subset of the MiT family translocation RCCs and characterized by harboring the Alpha-TFEB fusion gene. However, the development mechanism of this tumor and its effective treatment have not been fully identified yet. The purpose of this study was to explore the relationship between TFEB and BCL-2 in Alpha-TFEB stably transfected cell lines and in t(6;11) RCC tumor tissue. An Alpha-TFEB eukaryotic expression vector was constructed and stably transfected into CaKi-2 and HK-2 cells. RT-PCR and real-time RT-PCR were used to measure the mRNA expressions of TFEB and BCL-2, and immunohistochemistry, Western blot and dual immunofluorescence assays were used to evaluate the TFEB and BCL-2 protein expressions. MTT proliferation assays and flow cytometry were also performed. Furthermore, luciferase reporter assays were used to evaluate the BCL-2 promoter activity. An Alpha-TFEB eukaryotic expression vector was successfully constructed and stably transfected into CaKi-2 and HK-2 cells (named CaKi-2-TFEB and HK-2-TFEB cells). Compared with the CaKi-2 and HK-2 groups, the TFEB and BCL-2 mRNA expression levels were significantly upregulated in the CaKi-2-TFEB and HK-2-TFEB groups respectively. The TFEB and BCL-2 protein expressions showed a similar result. The overexpression of TFEB and BCL-2 promoted cell proliferation and inhibited cell apoptosis. Moreover, the overexpression of TFEB upregulated the promoter activity of BCL-2. Our data suggest that the overexpression of TFEB promotes BCL-2 expression by upregulating its promoter activity and ultimately results in the development of t(6;11) translocation RCC. BCL-2 inhibitors may serve as potential therapeutic targets for t(6;11) translocation RCC.