c‐Ski accelerates renal cancer progression by attenuating transforming growth factor β signaling

Abstract

Although transforming growth factor beta ( TGF ‐β) is known to be involved in the pathogenesis and progression of many cancers, its role in renal cancer has not been fully investigated. In the present study, we examined the role of TGF ‐β in clear cell renal carcinoma (cc RCC ) progression in vitro and in vivo. First, expression levels of TGF ‐β signaling pathway components were examined. Microarray and immunohistochemical analyses showed that the expression of c‐Ski, a transcriptional corepressor of Smad‐dependent TGF‐β and bone morphogenetic protein (BMP) signaling, was higher in cc RCC tissues than in normal renal tissues. Next, a functional analysis of c‐Ski effects was carried out. Bioluminescence imaging of renal orthotopic tumor models demonstrated that overexpression of c‐Ski in human cc RCC cells promoted in vivo tumor formation. Enhancement of tumor formation was also reproduced by the introduction of a dominant‐negative mutant TGF ‐β type II receptor into cc RCC cells. In contrast, introduction of the BMP signaling inhibitor Noggin failed to accelerate tumor formation, suggesting that the tumor‐promoting effect of c‐Ski depends on the inhibition of TGF ‐β signaling rather than of BMP signaling. Finally, the molecular mechanism of the tumor‐suppressive role of TGF ‐β was assessed. Although TGF ‐β signaling did not affect tumor angiogenesis, apoptosis of cc RCC cells was induced by TGF ‐β. Taken together, these findings suggest that c‐Ski suppresses TGF ‐β signaling in cc RCC cells, which, in turn, attenuates the tumor‐suppressive effect of TGF ‐β.

The Interactivity between TGFβ and BMP Signaling in Organogenesis, Fibrosis, and Cancer

“…Taguchi and colleagues reported that in clear cell renal carcinoma (ccRCC) the signaling of TGFβ, but not that of BMP, works in a tumor-suppressive mode, by inducing apoptosis. Consistently, the transcriptional corepressor c-Ski, which is highly expressed in ccRCC, promotes tumor growth by counteracting the TGFβ-dependent SMAD arm (that requires SMAD2/3), but probably not that related to BMP (that requires SMAD1/5/8) [155]. However, in another study, BMP9 was shown to inhibit the proliferation of HCC cell lines via inducing, in a SMAD-independent mode, the expression of cell cycle inhibitor p21.…”

Whole-organ analysis of TGF-β-mediated remodelling of the tumour microenvironment by tissue clearing

“…A549 cells were maintained in Dulbecco’s modified Eagle’s medium (#11965; Thermo Fisher Scientific, Waltham, MA) supplemented with 10% fetal bovine serum, 100 U/ml penicillin G, and 100 μg/ml streptomycin. To establish A549 cells stably expressing firefly luciferase and GFP under the CMV promoter, we used a lentiviral expression system (kindly provided by Prof. Hiroyuki Miyoshi, deceased, formerly Keio University, Tokyo, Japan) 46 . A549-Luc2-mCherry cells in the previous study were used as A549-mCherry cells 19 .…”

Genome-wide analysis of DNA methylation identifies the apoptosis-related gene UQCRH in renal cancer

“…The lentiviral vector system (provided by H. Miyoshi, deceased, formerly Keio University) was used for speci c gene overexpression and knockdown as previously described. [29] For UQCRH overexpression, the complementary DNA encoding human UQCRH was inserted into the multiple cloning site of the empty vector pENTR201. Recombination between pENTR201 and the destination vector CSII-CMV-RfA was performed using Gateway cloning technology (Thermo Fisher Scienti c).…”

“…Mouse renal orthotopic tumor models were generated as previously described. [29] Brie y, BALB/c-nu/nu male mice (5weeks-old) were purchased from Sankyo Labo Service Corporation (Tokyo, Japan). ccRCC cells (1.0 × 10 5 ) expressing Luc2 and mCherry were inoculated into the subrenal capsule of mice.…”