Biology subjects

Wesslowski, J.

Publications and source records attributed to Wesslowski, J..

4 recordsLinked to original sources

bioRxiv2025

Distinct 2-phenyl-imidazo pyridine derivatives drive ER degradation and selectively impair proliferation of ER+ breast cancer cells via the aryl hydrocarbon receptor

X15695 is a 2-phenyl-imidazo[1, 2] pyridine derivative identified as an orally active, selective oestrogen receptor (ER) degrader that inhibits the proliferation of ER+ breast cancer cells. Here, we show that X15695 is an aryl hydrocarbon receptor (AHR) ligand that stabilises the AHR more efficiently than its classical ligand, indirubin. X15695 enables AHR to form a complex with the ER, promoting its proteasomal degradation. In the presence of oestradiol, X15695 outperforms the standard of care drug fulvestrant in suppressing the growth of ER+ breast cancer cells, either expressing the wild-type or clinically relevant ER mutant forms (Y537S and D538G), and of patient-derived xenograft organoids established from ER+ tumours. Using computational techniques, we discovered that a low pKa value resulting from electron-withdrawing substituents in the 2-phenyl-imidazo[1, 2] pyridine compounds is a key feature that identify them as potent AHR ligands, leading to the potential discovery of additional derivatives for future therapeutic development.

cancer biology↗

bioRxiv2025

Wnt10b signaling regulates replication stress-induced chromosomal instability in human cancer

Wnt signaling pathways are involved in various developmental and tissue maintenance functions while deregulated Wnt signaling is closely linked to human cancer. Recent work revealed that loss of Wnt signaling impairs mitosis and causes abnormal microtubule growth at the mitotic spindle resulting in chromosome missegregation and aneuploidy, both of which are hallmarks of cancer cells exhibiting chromosomal instability (CIN). Here, we demonstrate that Wnt signaling specifically activated by Wnt10b is relevant in colorectal cancer cells to prevent abnormal microtubule dynamics and chromosome missegregation. Although mitosis is affected, Wnt10b signaling is required during the S phase of the cell cycle. In fact, Wnt10b signaling acts upon DNA replication stress in S phase, a condition typically associated with CIN in cancer, to prevent increased microtubule dynamics from S phase until mitosis, where they otherwise manifest in chromosome missegregation. Interestingly, replication stress-induced chromosomal breaks are also efficiently suppressed by Wnt10b. Thus, our results show that Wnt10b signaling regulates replication stress-induced chromosome missegregation and breakage, and hence, is a determinant for broad genome instability in cancer cells. Summary blurbWe describe a novel role of Wnt10b signaling acting in response to DNA replication stress to suppress chromosomal breaks and mitotic errors in human cancer cells.

cell biology↗

bioRxiv2025

Quantification of Wnt3a, Wnt5a and Wnt16 Binding to Multiple Frizzleds Under Physiological Conditions using NanoBit/BRET

Upon engagement of one of the 19 secreted Wnt signalling proteins with one of the 10 Frizzled transmembrane Wnt receptors (FZD1-10), a wide variety of cellular Wnt signalling responses can be elicited, the selectivity of which depends on: 1) the specific Wnt-FZD pairing, 2) the participation of Wnt co-receptors, and 3) the cellular context. Co-receptors play a pivotal role in guiding the specificity of Wnt signaling, most notably between {beta}-catenin dependent and independent pathways, where co-receptors such as LRP5/6 and ROR1/2 / PTK7 play major roles, respectively. It remains less understood how specific Wnt/FZD combinations contribute to the selectivity of downstream Wnt signaling and we lack accurate comparative data on their binding properties under physiological conditions. Here, using fluorescently-tagged Wnt3a, Wnt5a and Wnt16 proteins and cell lines expressing HiBiT-tagged Frizzled, we build on our ongoing efforts to provide a complete overview of the biophysical properties of all Wnt/FZD interactions using full-length proteins. Our real-time NanoBRET analysis using living cells expressing low receptor levels provides more accurate quantification of binding and will help us understand how these binary engagements control Wnt signaling outputs. We also provide evidence that LRP6 regulates the binding affinity of Wnt/FZD interactions in the trimeric Wnt-FZD-LRP6 complex.

biochemistry↗

bioRxiv2022

Receptor levels determine binding affinity of WNT-3A to Frizzled 7 in a colorectal cancer model

WNT binding to Frizzleds (FZD) is a crucial step that leads to the initiation of signalling cascades governing multiple processes during embryonic development, stem cell regulation and adult tissue homeostasis. Recent efforts have enabled us to shed light on WNT-FZD pharmacology in overexpressed HEK293 cell systems. However, it is important to assess ligand binding at endogenous receptor levels as there might be differential binding behaviour in a native environment. Here, we focus on one FZD paralogue: FZD7, and study its interactions with WNT-3A in a CRISPR-Cas9-edited SW480 colorectal cancer model. SW480 cells were CRISPR-Cas9-edited to insert a HiBiT-tag on the N-terminus of FZD7, preserving the native signal peptide. Subsequently, these cells were used to study eGFP-WNT-3A association to endogenous and overexpressed HiBiT-FZD7 using NanoBiT/BRET to measure ligand binding and quantification of NanoBiT-emitted luminescence to assess receptor internalization. eGFP-WNT-3A bound to endogenous HiBiT-FZD7 with significantly higher kon and with lower Kd than to overexpressed receptors. Importantly, as the fluorescent probe is an agonist, experiments performed in cell lysates demonstrated that eGFP-WNT-3A/HiBiT-FZD7 binding assessment is not altered by receptor internalization. In conclusion, binding affinities of eGFP-WNT-3A to HiBiT-FZD7 decreased with increasing receptor concentrations suggesting that HiBiT-FZD7 overexpression fails to recapitulate ligand binding behaviour in a (patho-)physiologically relevant context where endogenous receptor expression levels are lower.

pharmacology and toxicology↗