Biology subjects

Maurice, M.

Publications and source records attributed to Maurice, M..

4 recordsLinked to original sources

bioRxiv2025

E3 ubiquitin-ligase Hakai induces LRP4 degradation and regulates Wnt/beta-catenin signalling in colorectal cancer cells

The epithelial-mesenchymal transition (EMT) is closely linked to the acquisition of cancer stem cell (CSC) properties, which contribute to treatment resistance and metastasis. This study investigates the role of the E3 ubiquitin-ligase Hakai, the first identified post-translational regulator of E-cadherin stability, in promoting CSC traits in colorectal cancer (CRC). To examine Hakais involvement in CSC regulation, we used an inducible shRNA in a HT29 cells. Under conditions that promote CSC characteristics, we silenced Hakai and evaluated tumoursphere formation and CSC marker expression. Proteomic and bioinformatic analyses were performed to identify Hakai-regulated proteins in tumoursphere cultures. Additionally, Western blot, RT-qPCR, co-immunoprecipitation, immunofluorescence and TOPFlash assays were employed to study CSC-related protein regulation in response to Hakai expression. Furthermore, we assessed the impact of Hakin-1, the pharmacological inhibitor specifically targeting Hakais HYB domain responsible for its E3 ubiquitin-ligase activity, on tumoursphere properties. Hakai silencing significantly reduced tumoursphere size and number accompanied by decreased expression of CSC markers and Wnt target genes. CSC-related proteins regulated by Hakai were identified, including LRP4, a negative regulator of Wnt/{beta}-catenin pathway. Hakai interacts with LRP4, promoting its ubiquitination and degradation. Moreover, Hakai overexpression induces hyperactivation of Wnt/{beta}-catenin sand disrupts LRP4s inhibitory effect. Treatment with Hakin-1 effectively inhibited self-renewal and promoted differentiation within tumourspheres. These findings suggest that Hakai promotes CSCs properties by hyperactivation of the Wnt/{beta}-catenin pathway via LRP4-mediated modulation. Additionally, Hakin-1 emerges as a promising therapeutic agent targeting CSCs by enhancing differentiation and attenuating Wnt/{beta}-catenin activity, highlighting Hakai as a potential target for improving CSC treatment.

cancer biology↗

bioRxiv2025

WNK kinase regulates plasma membrane levels of the WNT inhibitor RNF43

The E3 ubiquitin ligases RNF43 and ZNRF3 are key negative regulators of canonical WNT signaling, promoting turnover of the WNT receptors FRIZZLED and LRP5/6 at the plasma membrane. While their mechanism of action is well established, how RNF43/ZNRF3 themselves are regulated remains unclear. Here, we identify WNK kinases as novel upstream regulators of RNF43 through proximity labeling proteomics. Using gain- and loss-of-function approaches, we show that WNKs control RNF43 surface localization and thereby its ability to ubiquitinate and downregulate WNT receptors. Pharmacological inhibition of WNKs increases RNF43 membrane abundance and enhances WNT suppression - an effect abolished in RNF43/ZNRF3 double knockout cells and organoids. Mechanistically, WNK inhibition alters RNF43 trafficking and ubiquitination, revealing a role for WNKs in regulating its plasma membrane distribution. These findings define a new regulatory axis linking the pro-WNT activity of WNKs to RNF43/ZNRF3-mediated feedback inhibition. Targeting WNK now offers a novel therapeutic strategy to restore WNT pathway control in cancers with RSPO fusions or RNF43 mutations.

biochemistry↗

bioRxiv2023

Stabilisation of β-Catenin-WNT signalling by USP10 in APC-truncated colorectal cancer drives cancer stemness and enables super-competitor signalling

The contribution of deubiquitylating enzymes to {beta}-Catenin stabilisation in intestinal stem cells and colorectal cancer (CRC) is poorly understood. Here, we report the deubiquitylase USP10 as an APC-truncation- specific enhancer of {beta}-Catenin stability, potentiating WNT signalling in CRC and cancer stem cells. Mechanistically, interaction studies in various CRC cell lines and in vitro binding studies, together with computational modelling, revealed that USP10 binding to {beta}-Catenin is mediated via the unstructured N-terminus of USP10 and requires the absence of full-length APC. Notably, loss of USP10 in CRISPR engineered intestinal organoids reduces tumorigenic properties of CRC and blocks the super competitor-signalling of APC-mutated CRC. Furthermore, reduction of USP10 induces the expression of differentiation genes, and opposes the APC-truncated phenotype in an intestinal hyperplasia model of D.melanogaster. Taken together, our findings reveal USP10s role in intestinal tumourigenesis by stabilising {beta}-Catenin, leading to aberrant WNT signalling, enhancing cancer cell stemness and implicate the DUB USP10 as a cancer specific therapeutic vulnerability in Apc truncated CRC.

cancer biology↗

bioRxiv2022

A peptide strategy for inhibiting different protein aggregation pathways in disease

Protein aggregation correlates with many human diseases. Protein aggregates differ in shape, ranging from amorphous aggregates to amyloid fibrils. Possibly for such heterogeneity, strategies to develop effective aggregation inhibitors that reach the clinic failed so far. Here, we present a new strategy by which we developed a family of peptides targeting early aggregation stages for both amorphous and fibrillar aggregates of proteins unrelated in sequence and structure. Thus, they act on dynamic precursors before a mechanistic differentiation takes place. Using a peptide array approach, we first identified peptides inhibiting the predominantly amorphous aggregation of a molten globular, aggregation-prone protein, a thermolabile mutant of the Axin tumor suppressor. A series of optimization steps revealed that the peptides activity did not depend on their sequences but rather on their molecular determinants. The key properties that made a peptide active were a composition of 20-30% flexible, 30-40% aliphatic and 20-30% aromatic residues, a hydrophobicity/hydrophilicity ratio close to 1 and an even distribution of residues of different nature throughout the sequence. Remarkably, the optimized peptides also suppressed fibrillation of Tau, a disordered protein that forms amyloids in Alzheimers disease, and entirely unrelated to Axin. Our compounds thus target early aggregation stages, independent of the aggregation mechanism, inhibiting both amorphous and amyloid aggregation. Such cross-mechanistic, multi-targeting aggregation inhibitors may be attractive lead compounds against multiple protein aggregation diseases.

biochemistry↗