Endothelial inflammation is regulated by a complex molecular mechanism. TC1(C8orf4) is a novel regulator implicated in cancer and inflammation. It is a small protein conserved well among vertebrates. In zebrafish embryos, it is mostly expressed in angio-hematopoietic system and the overexpression induces edema. In human aortic endothelial cells and umbilical vein endothelial cells, TC1 transfection up-regulates key inflammatory cytokines, enzymes, and adhesion proteins including IL-6, IL-1α, COX-2, CXCL1, CCL5, CCL2, IL-8, ICAM1, VCAM1, and E-selectin, while TC1 knockdown down-regulates them. TC1 also enhances inflammatory parameters such as monocyte-endothelial adhesion and endothelial monolayer permeability. TC1 is up-regulated by IL-1β, TNF-α, LPS, and phorbol ester, and the up-regulation is inhibited by I-κB-kinase inhibitors. TC1, in turn, enhances the nuclear translocation of RelA and the DNA binding activity, suggesting a biological role of amplifying NF-κB signaling via a positive feedback. Our findings suggest that TC1 is a novel endothelial inflammatory regulator that might be implicated in inflammatory vascular diseases.

Background Androgen receptor (AR)-targeted treatments improve the survival of castration-resistant prostate cancer (CRPC) patients; however, secondary resistance to these agents ultimately occurs in virtually all patients. Therefore, alternative therapeutic targets are urgently needed. Since growing evidence demonstrates that WNT/β-catenin signaling plays an important role in CRPC, the antitumor activity and mechanism of action of CWP232291, a small molecule β-catenin inhibitor, were investigated in prostate cancer. Methods We assessed the antitumor activity of CWP232291 in prostate cancer cell lines and primary cells derived from CRPC patients. The effect of CWP232291 on apoptotic cell death, endoplasmic reticulum (ER) stress, cell viability, and WNT/β-catenin signaling was evaluated by flow cytometry, western blotting, luciferase reporter assay, and fluorescence microscopy. Antitumor efficacy was assessed in two CRPC xenograft mouse models. Results CWP232291 induced ER stress, resulting in upregulation of the proapoptotic protein CHOP and activation of caspase-3-dependent apoptosis. In addition, CWP232291 suppressed the expression of β-catenin by affecting WNT-dependent transcriptional activity, and downregulated AR and its splice variants in prostate cancer cells. Antitumor activity was observed in prostate cancer cells in vitro and ex vivo, and antitumor efficacy was observed in vivo. Conclusions Beyond providing preclinical evidence of therapeutic efficacy for the novel small molecule β-catenin inhibitor CWP232291 in CRPC, our results show that inducing ER stress and targeting WNT/β-catenin signaling may be a novel strategy against CRPC. Electronic supplementary material The online version of this article (10.1186/s13046-019-1342-5) contains supplementary material, which is available to authorized users.

The combination of GSK2126458 and AZD6244 blocks both the RAS/RAF/MEK/ERK and PI3K/AKT/mTOR pathways simultaneously and is an effective strategy for the treatment of CRPCs.