Yamaguchi M, Ghanem NZ, Hashimoto K, Ramos JW, Murata T. The overexpressed transcription factor RGPR-p117 suppresses the proliferation of normal rat kidney proximal tubular epithelial NRK-52E cells: Involvement of diverse signaling pathways.
Life Sci 2022;
306:120795. [PMID:
35835253 DOI:
10.1016/j.lfs.2022.120795]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/27/2022] [Accepted: 07/07/2022] [Indexed: 11/17/2022]
Abstract
AIMS
RGPR-p117 was originally discovered as a novel transcription factor, which specifically binds to a nuclear factor I (NFI) consensus motif TTGGC(N)6CC in the promoter region of the regucalcin gene. RGPR-p117 is also called as Lztr2 and SEC16B. The role of RGPR-p117 in cell regulation is poorly understood. This study was undertaken to determine whether the overexpression of RGPR-p117 impacts the proliferation of normal rat kidney proximal tubular epithelial NRK-52E cells in vitro.
MAIN METHODS
The NRK-52E wild-type cells and RGPR-p117-overexpressing NRK-52E cells were cultured in DMEM containing fetal bovine serum.
KEY FINDINGS
The overexpression of RGPR-p117 repressed colony formation and proliferation of NRK-52E cells. Interestingly, RGPR-p117 overexpression blocked cell proliferation promoted by culturing with Bay K 8644, a calcium-entry agonist, and phorbol 12-myristate 13-acetate, an activator of protein kinase C. The depressive effects of RGPR-p117 overexpression on cell proliferation were not occurred by culturing with various inhibitors of cell cycle and intracellular signaling processes. RGPR-p117 overexpression increased the translocation of RGPR-p117 into the nucleus of NRK-52E cells. Mechanistically, RGPR-p117 overexpression diminished the levels of Ras, PI3 kinase, Akt, mitogen-activated protein kinase, and mTOR, while it raised the levels of p53, Rb, p21, and regucalcin. Furthermore, RGPR-p117 overexpression protected cell death caused by apoptosis-inducing factors, suggesting that the suppressive effects of RGPR-p117 on cell growth are independent of cell death.
SIGNIFICANCE
The present study demonstrates that the overexpressed transcription factor RGPR-p117 suppresses cell proliferation via targeting diverse signaling processes, suggesting a role of RGPR-p117 in cell regulation.
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