Involvement of the NF-kappa B/p50/Bcl-3 complex in response to antiangiogenic therapy in a mouse model of metastatic renal cell carcinoma

Abstract

Renal cell carcinoma (RCC) represents approximately 2-3% of human malignancies. Nuclear transcription factor kappa B (NF-kappa B) is composed of a family of transcription factors that have been associated with the development and progression of RCC. Endostatin (ES) is a fragment of collagen XVIII that possesses antiangiogenic activity. in this study, we evaluated the expression of NF-kappa B in metastatic tumor cells from animals treated with ES. Balb/c-bearing Renca-EGFP cells were treated with NIH/3T3-LendSN or NIH/3T3-LXSN cells as a control. At the end of the in vivo experiment, plasma Renca-EGFP-sorted cells and tissue lung samples were collected. A real-time PCR array for NF-kappa B target genes revealed that ES therapy led to down regulation of Bcl-3 (P < 0.031), NF-kappa B1 (P < 0.001) and c-Rel (P < 0.004) in the ES-treated group. Using an electrophoretic mobility shift assay (EMSA), we observed a reduction in NF-kappa B binding activity in ES-treated Renca-EGP cells. Furthermore, a supershift assay showed a clear shift of the NF-kappa B DNA band in samples incubated with a p50 antibody. By immunohistochemistry analysis, ES treatment resulted in a significant reduction in expression of p50. (ES vs. control P < 0.05). the immunoprecipitation experiments confirmed the presence of a p50/Bcl-3 complex in nuclear extracts from cells of metastatic lung tissues. Our findings indicate that p50 and Bcl-3 plays a regulatory role in gene transcription in RCC. (C) 2014 Elsevier Masson SAS. All rights reserved.