The Therapeutic Role of PNU-74654 in Hepatocellular Carcinoma May Involve Suppression of NF-κB Signaling

PNU-74654 Induces Cell Cycle Arrest and Inhibits EMT Progression in Pancreatic Cancer

Background and Objectives: PNU-74654, a Wnt/β-catenin pathway inhibitor, has an antiproliferative effect on many cancer types; however, its therapeutic role in pancreatic cancer (PC) has not yet been demonstrated. Here, the effects of PNU-74654 on proliferation and cell cycle phase distribution were studied in PC cell lines. Materials and Methods: The cancer-related molecular pathways regulated by PNU-74654 were determined by a proteome profiling oncology array and confirmed by western blotting. Results: The cell viability and proliferative ability of PC cells were decreased by PNU-74654 treatment. G1 arrest was observed, as indicated by the downregulation of cyclin E and cyclin-dependent kinase 2 (CDK2) and the upregulation of p27. PNU-74654 inhibited the epithelial-mesenchymal transition (EMT), as determined by an increase in E-cadherin and decreases in N-cadherin, ZEB1, and hypoxia-inducible factor-1 alpha (HIF-1α). PNU-74654 also suppressed cytoplasmic and nuclear β-catenin and impaired the NF-κB pathway. Conclusions: These results demonstrate that PNU-74654 modulates G1/S regulatory proteins and inhibits the EMT, thereby suppressing PC cell proliferation, migration, and invasion. The synergistic effect of PNU-74654 and chemotherapy or the exclusive use of PNU-74654 may be therapeutic options for PC and require further investigation.

Wnt Signaling in Brain Tumors: A Challenging Therapeutic Target

The involvement of Wnt signaling in normal tissue homeostasis and disease has been widely demonstrated over the last 20 years. In particular, dysregulation of Wnt pathway components has been suggested as a relevant hallmark of several neoplastic malignancies, playing a role in cancer onset, progression, and response to treatments. In this review, we summarize the current knowledge on the instructions provided by Wnt signaling during organogenesis and, particularly, brain development. Moreover, we recapitulate the most relevant mechanisms through which aberrant Wnt pathway activation may impact on brain tumorigenesis and brain tumor aggressiveness, with a particular focus on the mutual interdependency existing between Wnt signaling components and the brain tumor microenvironment. Finally, the latest anti-cancer therapeutic approaches employing the specific targeting of Wnt signaling are extensively reviewed and discussed. In conclusion, here we provide evidence that Wnt signaling, due to its pleiotropic involvement in several brain tumor features, may represent a relevant target in this context, although additional efforts will be needed to: (i) demonstrate the real clinical impact of Wnt inhibition in these tumors; (ii) overcome some still unsolved concerns about the potential systemic effects of such approaches; (iii) achieve efficient brain penetration.

Canonical Wnt signaling enhances pro-inflammatory response to titanium by macrophages

Biomaterial characteristics like surface roughness and wettability can determine the phenotype of macrophages following implantation. We have demonstrated that inhibiting Wnt ligand secretion abolishes macrophage polarization in vitro and in vivo; however, the role of canonical Wnt signaling in macrophage activation in response to physical and chemical biomaterial cues is unknown. The aim of this study was to understand whether canonical Wnt signaling affects the response of macrophages to titanium (Ti) surface roughness or wettability in vitro and in vivo. Activating canonical Wnt signaling increased expression of toll-like receptors and interleukin receptors and secreted pro-inflammatory cytokines and reduced anti-inflammatory cytokines on Ti, regardless of surface properties. Inhibiting canonical Wnt signaling reduced pro-inflammatory cytokines on all Ti surfaces and increased anti-inflammatory cytokines on rough or rough-hydrophilic Ti. In vivo, activating canonical Wnt signaling increased total macrophages, pro-inflammatory macrophages, and T cells and decreased anti-inflammatory macrophages on both smooth and rough-hydrophilic implants. Functionally, canonical Wnt activation increases pro-inflammatory macrophage response to cell and cell-extracellular matrix lysates. These results demonstrate that activating canonical Wnt signaling primes macrophages to a pro-inflammatory phenotype that affects their response to Ti implants in vitro and in vivo.