Background: The WNT/planar-cell-polarity (PCP) pathway is a key
regulator of cell polarity and directional cell movements. Core
PCP proteins such as Van Gogh-like2 (VANGL2) are evolutionarily
highly conserved; however, the mammalian PCP machinery is still
poorly understood mainly due to lack of suitable models and
quantitative methodology. WNT/PCP has been implicated in many
human diseases with the most distinguished positive role in the
metastatic process, which accounts for more than 90% of cancer
related deaths, and presents therefore an attractive target for
pharmacological interventions. However, cellular assays for the
assessment of PCP signaling, which would allow a more detailed
mechanistic analysis of PCP function and possibly also high
throughput screening for chemical compounds targeting mammalian
PCP signaling, are still missing. Results: Here we describe a
mammalian cell culture model, which correlates B lymphocyte
migration of patient-derived MEC1 cells and asymmetric
localization of fluorescently-tagged VANGL2. We show by live
cell imaging that PCP proteins are polarized in MEC1 cells and
that VANGL2 polarization is controlled by the same mechanism as
in tissues i.e. it is dependent on casein kinase 1 activity. In
addition, destruction of the actin cytoskeleton leads to
migratory arrest and cell rounding while VANGL2-EGFP remains
polarized suggesting that active PCP signaling visualized by
polarized distribution of VANGL2 is a cause for and not a
consequence of the asymmetric shape of a migrating cell.
Conclusions: The presented imaging-based methodology allows
overcoming limitations of earlier approaches to study the
mammalian WNT/PCP pathway, which required in vivo models and
analysis of complex tissues. Our system investigating PCP-like
signaling on a single-cell level thus opens neew possibilities
for screening of compounds, which control asymmetric
distribution of proteins in the PCP pathway.

Asymmetry of VANGL2 in migrating lymphocytes as a tool tomonitor activity of the mammalian WNT/planar cell polaritypathway

Colorectal cancer (CRC) represents one of the most common cancers worldwide, with a high mortality rate despite the decreasing incidence and new diagnostic and therapeutic strategies. CRC arises from both epidemiologic and molecular backgrounds. In addition to hereditary factor and genetic mutations, the strongly varying incidence of CRC is closely linked to chronic inflammatory disorders of the intestine and terrible dietary habits. The Wnt signalling pathway is a complex regulatory network that is implicated in many CRC physiological processes, including cancer occurrence, development, prognosis, invasion, and metastasis. It is currently believed to include classical Wnt/β-catenin, Wnt/PCP, and Wnt/Ca2+. In this review, we summarise the recent mechanisms and potential regulators of the three branches of the Wnt signalling pathway in CRC.

/pdf/advances-of-wnt-signalling-pathway-in-colorectal-cancer-12xyusr1.pdf

Advances of Wnt Signalling Pathway in Colorectal Cancer

The core planar cell polarity (PCP) protein Vang/Vangl, including Vangl1 and Vangl2 in vertebrates, is indispensable during development. Our previous studies showed that the activity of Vangl is tightly controlled by two important posttranslational modifications, ubiquitination and phosphorylation. Vangl is ubiquitinated through an endoplasmic reticulum-associated degradation (ERAD) pathway and is phosphorylated by casein kinase 1 (CK1) in response to Wnt. Here, we present step-by-step procedures to analyze Vangl ubiquitination and phosphorylation, including cell culture, transfection, sample preparation, and signal detection, as well as the use of newly available phospho-specific antibodies to detect Wnt-induced Vangl2 phosphorylation. The protocol described here can be applicable to the analysis of posttranslational modifications of other membrane proteins.

Analysis of the Ubiquitination and Phosphorylation of Vangl Proteins.

http://www.cell.com/article/S1471491423000667/pdf

Cells of the tumor microenvironment speak the Wnt language.

Krüppel-like factors (KLFs) are a group of DNA-binding transcriptional regulators with multiple essential functions in various cellular processes, including proliferation, migration, inflammation, and angiogenesis. The aberrant expression of KLFs is often found in tumor tissues and is essential for tumor development. At the molecular level, KLFs regulate multiple signaling pathways and mediate crosstalk among them. Some KLFs may also be molecular switches for specific biological signals, driving their transition from tumor suppressors to promoters. At the histological level, the abnormal expression of KLFs is closely associated with tumor cell stemness, proliferation, apoptosis, and alterations in the tumor microenvironment. Notably, the role of each KLF in tumors varies according to tumor type and different stages of tumor development rather than being invariant. In this review, we focus on the advances in the molecular biology of KLFs, particularly the regulations of several classical signaling pathways by these factors, and the critical role of KLFs in tumor development. We also highlight their strong potential as molecular targets in tumor therapy and suggest potential directions for clinical translational research.

/pdf/kruppel-like-factors-in-tumors-key-regulators-and-2dhf61us.pdf

Krüppel-like factors in tumors: Key regulators and therapeutic avenues

Since the discovery of the proto-oncogene Wnt1 (Int1) in 1982, WNT signaling has been identified as one of the most important pathways that regulates a wide range of fundamental developmental and physiological processes in multicellular organisms. The canonical WNT signaling pathway depends on the stabilization and translocation of β-catenin and plays important roles in development and homeostasis. The WNT/planar cell polarity (WNT/PCP) signaling, also known as one of the β-catenin-independent WNT pathways, conveys directional information to coordinate polarized cell behaviors. Similar to WNT/β-catenin signaling, disruption or aberrant activation of WNT/PCP signaling also underlies a variety of developmental defects and cancers. However, the pharmacological targeting of WNT/PCP signaling for therapeutic purposes remains largely unexplored. In this review, we briefly discuss WNT/PCP signaling in development and disease and summarize the known drugs/inhibitors targeting this pathway.

Di Feng

Papers

An Overview of Potential Therapeutic Agents Targeting WNT/PCP Signaling