Knockdown of LETM1 inhibits proliferation and metastasis of human renal cell carcinoma cells.

The leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) has been reported to serve an important role in a number of human malignancies and is correlated with poor prognosis. However, little is known about the role of LETM1 in renal cell carcinoma (RCC). In the present study, the expression levels of LETM1 were investigated in RCC cell lines (Caki-1, 786-O, OS-RC-2, A498 and ACHN) and the HK-2 normal human renal tubular epithelial cell line. Short interfering RNA (siRNA) was used to knock down the expression of LETM1 in 786-O and A498 cells. The results indicated that the constitutive expression of LETM1 was notably upregulated in RCC cell lines. Knockdown of LETM1 significantly decreased cell proliferation, migration and invasion. Mechanistically, it was revealed that the knockdown of LETM1 expression sharply downregulated the protein expression of β-Catenin, Cyclin D1 and c-Myc in 786-O and A498 cells. In conclusion, these results suggest that knockdown of LETM1 exhibits tumor suppressive effects, at least in part by controlling the downstream Wnt/β-Catenin signaling pathway. Therefore, LETM1 may act as a novel therapeutic target for the treatment of RCC.