Decrease of phosphorylated proto-oncogene CREB at Ser 133 site inhibits growth and metastatic activity of renal cell cancer

Abstract

Objective: Cyclic-AMP-responsive element-binding protein (CREB) is a proto-oncogenic transcription factor. The authors’ previous reports showed that blocking the CREB binding site at Ser 133 inhibited the expression of target genes, which related to the progression of some tumors. In this study, the authors investigated the role of phosphorylated CREB (pCREB) at Ser133 in renal cell carcinoma (RCC) growth and metastases.

Methods: Immunohistochemistry, xenograft model in nude mice, cell proliferation assay, cell invasion/migration assay, fluorescent immunocytochemistry and Western analysis were performed in an immortalized proximal tubule epithelial cell line and clear-cell RCC.

Results: The authors’ results showed that knockdown of pCREB inhibited kidney cancer cells growth in vivo. Furthermore, suppression of the pCREB level blunted the capabilities of cell migration and invasion in vitro and was accompanied with significantly decreased expression of MMP-2 and MMP-9, the filopodia formation and epithelial-mesenchymal transition-related proteins. Surprisingly, no changes of expression or location of vimentin were revealed in the experiment. Bioinformatic software explained the possible reason for this is that the promoter of vimentin does not contain the CRE sequence.

Conclusions: These data suggest that decreasing the level of pCREB inhibits the growth and metastasis of RCC by targeting the Ser 133 site.

Keywords:

• cyclic-AMP-responsive element-binding protein
• growth
• metastasis
• renal cell cancer

Acknowledgment

X Wang and Y Ren contributed equally to this study.

Declaration of interest

This work was supported by the grants from National Natural Science Foundation of China (81372209, 81071653), Zhejiang Provincial Natural Science Foundation of China (LY13H160038), Ningbo Natural Science Foundation (2014A610239), Scientific Plan of Medical and Health of Zhejiang Province (2015RCB024) and K. C. Wong Magna Fund in Ningbo University. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Notes