Biology subjects

Hyvönen, M.

Publications and source records attributed to Hyvönen, M..

4 recordsLinked to original sources

bioRxiv2025

Targeting a Pleckstrin Homology Domain with a Lysine-Reactive Cova-lent Binder

Brutons Tyrosine Kinase (BTK) is a validated target for haematological malignancies, with numerous FDA approved inhibitors on the market. Current therapies target the highly conserved ATP binding site and hence limit the therapeutic index given the sites highly conserved nature across the kinome. We explore a novel approach for BTK inhibition, by targeting the PH domain-mediated membrane recruitment and activation of BTK. We have identified a fragment which covalently labels a lysine in the inositol phosphate (PIP3) binding site. Fragment growth and an extensive structure-binding relationship study uncovered 27 crystal structures and a best-in-class analog, 24. Evaluation of pKa values of the targeted lysine in BTK and other PH domains suggests this as a more general approach to PH domain inhibition.

biochemistry↗

bioRxiv2023

Selective inhibitors of the Aurora A-TPX2 protein-protein interaction exhibit in vivo efficacy as targeted anti-mitotic agents

The protein kinase Aurora A, and its close relative, Aurora B, regulate human cell division. Aurora A is frequently overexpressed in cancers of the breast, ovary, pancreas and blood, provoking genome instability and resistance to anti-mitotic chemotherapy. Intracellular localization and enzymatic activity of Aurora A are regulated by its interaction with the spindle assembly factor TPX2. Here, we have used fragment-based, structure-guided lead discovery to develop small-molecule inhibitors of the Aurora A-TPX2 protein-protein interaction (PPI). These compounds act by novel mechanism compared to existing Aurora A inhibitors and they are highly specific to Aurora A over Aurora B. Our biophysically, structurally and phenotypically validated lead compound, CAM2602, exhibits oral bioavailability, favourable pharmacokinetics, pharmacodynamic biomarker modulation, and arrest of growth in tumour xenografts. Consistent with our original finding that Aurora A overexpression drives taxane-resistance in cancer cells, inhibition of Aurora A-TPX2 PPI synergizes with paclitaxel to suppress the outgrowth of pancreatic cancer cells. Our results provide a blueprint for targeting the Aurora A-TPX2 PPI for cancer therapy and suggest a promising clinical utility for this mode of action.

biochemistry↗

bioRxiv2019

Thrombospondin module 1 domain (TSP1) of the matricellular protein CCN3 shows an atypical disulfide pattern and incomplete CWR layers

Members of the CCN (Cyr61/CTGF/Nov) family are a group of matricellular regulatory proteins, essential to a wide range of functional pathways in cell signalling. Through interacting with extracellular matrix components and growth factors via one of its four domains, the CCN proteins are involved in critical biological processes such as angiogenesis, cell proliferation, bone development, fibrogenesis, and tumorigenesis. We present here the crystal structure of the thrombospondin module 1 (TSP1) domain of CCN3 (previously known as Nov), which shares a similar three-stranded fold with the thrombospondin type 1 repeats of thrombospondin-1 and Spondin-1, but with variations in the disulfide connectivity. Moreover, the CCN3 TSP1 lacks the typical pi-stacked ladder of charged and aromatic residues on one side of the domain, as seen in other TSP1 domains. Using conservation analysis among orthologous domains, we show that a charged cluster in the centre of the domain is the most conserved site and predict it to be a potential functional epitope for heparan sulphate binding. This variant TSP1 domain has also been used to revise the sequence determinants of TSP1 domains and derive improved Pfam sequence profiles for identification of novel TSP1 domains in more than 10,000 proteins across diverse phyla.\n\nSynopsisThe first structure of a thrombospondin module 1 domain (TSP1) from a CCN family matricellular protein has been determined by X-ray crystallography. The structure shows a typical three-stranded fold, but with an incomplete pi-stacked structure that is usually found in these domains. The structure reveals highest conservation in the positively charged central segment, which we predict to be a binding site for heparan sulphates. The atypical features of this domain have been used to revise the definition of the TSP1 domains and identify a number of new domains in sequence databases.

biochemistry↗

bioRxiv2018

Vulnerability of invasive glioma cells to lysosomal membrane instabilization

Diffusive by nature, glioma challenges clinical care by the impossibility of complete surgical resection of tumor, leaving the radio- and chemoresistant cells responsible for recurrence intact. We identified mammary-derived growth inhibitor (MDGI/FABP3) as invasive glioma biomarker. Here, we show that high MDGI expression associated with poor patient survival and promoted invasive glioma cell growth both in vitro and in vivo, while MDGI silencing drastically compromised patient-derived tumoroid viability via induction of lysosomal membrane permeabilization (LMP). This alternative cell death pathway provokes release of lysosomal hydrolases into the cytosol leading inevitably to the cell death. Our results show a novel functional role for MDGI in glioma cell invasion, survival, and maintenance of the lysosomal membrane integrity as well as an unsuspected sensitivity of glioma cells to an LMP-inducing drug, anti-histamine clemastine. In a preclinical study, clemastine-treatment significantly prolonged the survival of intracranial glioblastoma-bearing animals due to eradication of invasive glioma cells. This glioma cell vulnerability to LMP-inducing drugs opens new horizons for development of novel treatments and suggest re-positioning of an established drug for new indication.

cancer biology↗