SF3B4 promotes Twist1 expression and clear cell renal cell carcinoma progression by facilitating the export of KLF 16 mRNA from the nucleus to the cytoplasm

Abstract

Splicing factor 3B subunit 4 (SF3B4) plays important functional roles not only in pre-mRNA splicing, but also in the regulation of transcription, translation, and cell signaling, and its dysregulation contributes to various diseases including Nager syndrome and tumorigenesis. However, the role of SF3B4 and underlying mechanisms in clear cell renal cell carcinoma (ccRCC) remain obscure. In the present study, we found that the expression of SF3B4 was significantly elevated in ccRCC tissues and negatively correlated with the overall survival of ccRCC patients. Upregulation of SF3B4 promotes migration and invasion of ccRCC cells in vitro and in vivo. The promoting effect of SF3B4 on cell migration and invasion is mediated by Twist1, a key transcription factor to mediate EMT. Interestingly, SF3B4, a component of the pre-mRNA spliceosome, is able to promote KLF16 expression by facilitating the transport of KLF16 mRNA into the cytoplasm. Mechanistically, SF3B4 promotes the export of KLF16 mRNA from the nucleus to the cytoplasm and thus enhances KLF16 expression, and in turn elevated KLF16 directly binds to the Twist1 promoter to activate its transcription, leading to EMT and ccRCC progression. Our findings provide evidence that the SF3B4-KLF16-Twist1 axis plays important functional roles in the development and progression of ccRCC, and manipulating this pathway may be a novel therapeutic target for the treatment of ccRCC.

Adrenomedullin/FOXO3 enhances sunitinib resistance in clear cell renal cell carcinoma by inhibiting FDX1 expression and cuproptosis

“…Finally, the cells were cultured in 0.5 μM sunitinib medium. The transfection was performed using lipofectamine 2000 (Invitrogen) according to the manufacturer's protocols 19 …”

“…Tissue sections were used for HE and immunohistochemistry staining. Immunohistochemical staining was performed as described previously 19 . Tissue sections were dewaxed to water, followed by antigenic repair.…”

“…Transfected or treated cells (50 cells/well) were inoculated into 12‐well plates for 7–10 days and fixed in glacial acetic acid or methanol. Finally, the colonies were stained with 0.25% crystal violet, and clones were counted under a microscope 19 …”

“…The transfection was performed using lipofectamine 2000 (Invitrogen) according to the manufacturer's protocols. 19…”

“…Immunohistochemical staining was performed as described previously. 19 Tissue sections were dewaxed to water, followed by antigenic repair. After H 2 O 2 treatment, the sections were blocked with fetal bovine serum (FBS) for 30 min and then incubated at 4°C overnight with primary antibody.…”