Anti-LCOR (aa 6-55) polyclonal antibody

Nuclear receptors (NRs) regulate gene transcription by recruiting coregulators, involved in chromatin remodeling and assembly of the basal transcription machinery. The NR-associated protein ligand-dependent corepressor (LCoR) has previously been shown to suppress hepatic lipogenesis by decreasing the binding of steroid receptor coactivators to thyroid hormone receptor. However, the role of LCoR in adipogenesis has not been established. Here, we show that LCoR expression is reduced in the early stage of adipogenesis in vitro. LCoR overexpression inhibited 3T3-L1 adipocyte differentiation, whereas LCoR knockdown promoted it. Using an unbiased affinity purification approach, we identified CCAAT/enhancer-binding protein (C/EBP), a key transcriptional regulator in early adipogenesis, and corepressor C-terminal binding proteins as potential components of an LCoR-containing complex in 3T3-L1 adipocytes. We found that LCoR directly interacts with C/EBP through its C-terminal helix-turn-helix domain, required for LCoR's inhibitory effects on adipogenesis. LCoR overexpression also inhibited C/EBP transcriptional activity, leading to inhibition of mitotic clonal expansion and transcriptional repression of C/EBP and peroxisome proliferator-activated receptor 2 (PPAR2). However, LCoR overexpression did not affect the recruitment of C/EBP to the promoters of C/EBP and PPAR2 in 3T3-L1 adipocytes. Of note, restoration of PPAR2 or C/EBP expression attenuated the inhibitory effect of LCoR on adipogenesis. Mechanistically, LCoR suppressed C/EBP-mediated transcription by recruiting C-terminal binding proteins to the C/EBP and PPAR2 promoters and by modulating histone modifications. Taken together, our results indicate that LCoR negatively regulates early adipogenesis by repressing C/EBP transcriptional activity and add LCoR to the growing list of transcriptional corepressors of adipogenesis.

Wnt signaling is an evolutionarily conserved signaling route required for development and homeostasis. While canonical, beta-catenin-dependent Wnt signaling is well studied and has been linked to many forms of cancer, much less is known about the role of non-canonical, beta-catenin-independent Wnt signaling. Here, we aimed at identifying a beta-catenin-independent Wnt target gene signature in order to understand the functional significance of non-canonical signaling in colon cancer cells. Gene expression profiling was performed after silencing of key components of Wnt signaling pathway and an iterative signature algorithm was applied to predict pathway-dependent gene signatures. Independent experiments confirmed several target genes, including PLOD2, HADH, LCOR and REEP1 as non-canonical target genes in various colon cancer cells. Moreover, non-canonical Wnt target genes are regulated via RoR2, Dvl2, ATF2 and ATF4. Furthermore, we show that the ligands Wnt5a/b are upstream regulators of the non-canonical signature and moreover regulate proliferation of cancer cells in a beta-catenin-independent manner. Our experiments indicate that colon cancer cells are dependent on both beta-catenin-dependent and -independent Wnt signaling routes for growth and proliferation.