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Wierbilowicz, K.

Publications and source records attributed to Wierbilowicz, K..

3 recordsLinked to original sources

De novo Design of Macrocyclic Molecular Glues

The engineering of induced proximity has transformed drug discovery, yet the development of molecular glues remains largely serendipitous and restricted to the retrospective optimisation of accidental discoveries. Here, we present EvoBind-multimer, a deep learning framework for the de novo design of molecular glues directly from protein sequences. Unlike structure-based docking, our method generates small macrocyclic peptides that bridge user-defined protein pairs without requiring prior interface knowledge or existing ligands. We applied this framework to recruit the E3 ligase VHL to two challenging oncoproteins: KRAS and BRD4. Live-cell NanoBRET demonstrated robust design-induced proximity for both pairs. Mechanistic validation demonstrated that the generated macrocycles form functional VHL-target ternary complexes capable of driving Cullin-RING ligase-dependent proteasomal degradation and downstream signalling shutdown. Finally, evaluation in patient-derived xenograft neuroblastoma tumoroids revealed that ternary complex processing is deeply context-dependent: identical macrocycles acted as potent degraders in one patient model, yet functioned as stabilising "LOCKTACs" in another, driving VHL-dependent target sequestration without turnover. By enabling the de novo design of induced proximity from sequence alone, EvoBind-multimer provides a route towards designing new protein functions.

bioinformatics↗

Parp7 generates an ADP-ribosyl degron that controls negative feedback of androgen signaling

AbstractThe androgen receptor (AR) tranduces the effects of circulating and tumor-derived androgens to the nucleus through ligand-induced changes in protein conformation, localization, and engagement with chromatin binding sites. Understanding these events and their integration with signal transduction is critical for defining how AR drives prostate cancer and unveiling pathway features that are amenable to therapeutic intervention. Here, we describe a novel post-transcriptional mechanism that controls AR protein levels on chromatin and associated gene output which is based on a highly selective, inducible degradation mechanism. We find that the mono-ADP-ribosyltransferase PARP7 generates an ADP-ribosyl degron on a single cysteine within the DNA binding domain of AR, which is then recognized by the ADP- ribose reader domain in the ubiquitin E3 ligase DTX2 and degraded by the proteasome. Mathematical modeling of the pathway suggested that PARP7 ADP-ribosylates chromatin-bound AR, a prediction that was validated in cells using an AR mutant that undergoes nuclear import but fails to bind DNA. Lysine- independent, non-conventional ubiquitin conjugation to ADP-ribosyl-cysteine and AR degradation by the proteasome forms the basis of a negative feedback loop that regulates specific modules of AR target genes. Our data expand the repertoire of mono-ADP-ribosyltransferase enzymes to include gene regulation based on highly selective protein degradation. One Sentence SummaryPARP7 mono-ADP-ribosylates the androgen receptor on Cys620 to mark the androgen receptor for ubiquitin conjugation by an E3 ligase with ADP-ribose reader function, resulting in in negative feedback of AR-dependent gene expression.

cancer biology↗

Induction of PARP7 Creates a Vulnerability for Growth Inhibition by RBN2397 in Prostate Cancer Cells

The ADP-ribosyltransferase PARP7 modulates protein function by conjugating ADP-ribose to the side chains of acceptor amino acids. PARP7 has been shown to affect gene expression in prostate cancer cells and certain other cell types by mechanisms that include transcription factor ADP-ribosylation. Here, we use a recently developed catalytic inhibitor to PARP7, RBN2397, to study the effects of PARP7 inhibition in androgen receptor-positive and androgen receptor-negative prostate cancer cells. We find that RBN2397 has nanomolar potency for inhibiting androgen-induced ADP-ribosylation of the androgen receptor. RBN2397 inhibits the growth of prostate cancer cells in culture when cells are treated with ligands that activate the androgen receptor, or the aryl hydrocarbon receptor, and induce PARP7 expression. We show that the growth inhibitory effects of RBN2397 are distinct from its enhancement of interferon signaling recently shown to promote tumor immunogenicity. RBN2397 treatment also induces trapping of PARP7 in a detergentresistant fraction within the nucleus, which is reminiscent of how inhibitors such as Talazoparib affect PARP1 fractionation. Because PARP7 is expressed in AR negative metastatic tumors and RBN2397 can affect cancer cells through multiple mechanisms, PARP7 may be an actionable target in advanced prostate cancer. SignificanceRBN2397 is a potent and selective inhibitor of PARP7 that reduces the growth of prostate cancer cells, including a model for treatment-emergent neuroendocrine prostate cancer. RBN2397 induces PARP7 trapping on chromatin, suggesting its mechanism of action might be similar to clinically-used PARP1 inhibitors.

cancer biology↗