Nonpeptidic, Polo-Box Domain-Targeted Inhibitors of PLK1 Block Kinase Activity, Induce Its Degradation and Target-Resistant Cells

Chapagai, Danda; Ramamoorthy, Gurusankar; Varghese, Jessy; Nurmemmedov, Elmar; McInnes, Campbell; Wyatt, Michael D.

doi:10.1021/acs.jmedchem.1c00133

Cited by 13 publications

(30 citation statements)

References 49 publications

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“…However, in the presence of 500 nM of BI2536, upon abbapolin addition, the tracer was measurably displaced from the FL PLK1 with an IC 50 value of 4.85 ± 1.31 μM. Of note, this value is 5.5-fold lower compared to 26.8 ± 5.0 μM, our previously published IC 50 value for this same abbapolin binding to the PBD fragment . Collectively, these findings provide new insights into the recognition of different PLK1 conformations while confirming prior observations that the binding of BI6727 to FL PLK1 enhanced the interaction between PLK1 and a very similar peptide (MAGPMQS[pT]PLNGAK) in an in vitro AlphaScreen assay …”

Section: Resultssupporting

confidence: 85%

“…Error bars in panels (E) and (F) represent the standard deviation of the mean of soluble PLK1 from the three replicates. (G) Structures of BI2536, BI6727 (volasertib), and abbapolin 12 …”

Section: Resultsmentioning

confidence: 99%

“…To further explore this conformational change and its impact on PBD binding, additional in vitro fluorescence polarization (FP) assays with purified PLK1 and a fluorescently tagged peptide PBD ligand (MAGPMQS[pT]PLNGAKK) were performed. Our prior work utilized the PBD domain of PLK1 in FP assays to screen PBD-targeted binders, with good signal-to-noise ratio and assay concurrence with other measures of PLK1 engagement. ,,, In comparison to polarization of the tracer, PBD domain interaction (Δ mP = 155 ± 7.07), the tracer: full-length (FL) PLK1 interaction at the highest [PLK1] produced a weaker Δ mP value of 60.5 ± 22.1, a less robust signal-to-noise ratio, and greater standard deviation (SD) value (Figure A, black circles). Interestingly, the presence of 50 nM of BI2536 increased Δ mP values by more than 2-fold to 142.7 ± 12.0, demonstrating a better interaction of the tracer and FL PLK1 when bound to BI2536 (Figure A).…”

Section: Resultsmentioning

confidence: 99%

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Structural Basis for Variations in Polo-like Kinase 1 Conformation and Intracellular Stability Induced by ATP-Competitive and Novel Noncompetitive Abbapolin Inhibitors

et al. 2023

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Polo-like kinase 1 (PLK1) is an essential protein kinase with multiple roles in mitotic progression. PLK1 consists of a kinase domain (KD) and a phosphopeptide-binding polobox domain (PBD), which is responsible for substrate recognition and subcellular localization. The regulation of PLK1 involves an autoinhibitory conformation in which KD and PBD interact. Our previous work identified PBD-binding molecules termed abbapolins that inhibit the cellular phosphorylation of a PLK1 substrate and induce the loss of intracellular PLK1.Here, we describe a comparison of the abbapolin activity with that of KD inhibitors to gain insight into conformational features of PLK1. As measured by a cellular thermal shift assay, abbapolins produce ligand-induced thermal stabilization of PLK1. In contrast, KD inhibitors decreased the soluble PLK1, suggesting that catalytic-site binding causes a less thermally stable PLK1 conformation. Binding measurements with full-length PLK1 and a KD inhibitor also demonstrated a conformational change. Interestingly, the cellular consequences of KD versus PBD engagement contrast as KD binding causes the accumulation of intracellular PLK1, whereas PBD binding produces a striking loss of nuclear PLK1. These data are consistent with the relief of autoinhibited PLK1 by KD binders; an explanation for these observations is presented using structures for the catalytic domain and full-length PLK1 predicted by AlphaFold. Collectively, the results highlight an underappreciated aspect of targeting PLK1, namely, conformational perturbations induced by KD versus PBD binding. In addition to their significance for PBD-binding ligands, these observations have implications for the development of ATP-competitive PLK1 inhibitors because catalytic inhibitors may conversely promote PLK1 noncatalytic functions, which may explain their lack of clinical efficacy to date.

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Section: Resultssupporting

confidence: 85%

“…Error bars in panels (E) and (F) represent the standard deviation of the mean of soluble PLK1 from the three replicates. (G) Structures of BI2536, BI6727 (volasertib), and abbapolin 12 …”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Structural Basis for Variations in Polo-like Kinase 1 Conformation and Intracellular Stability Induced by ATP-Competitive and Novel Noncompetitive Abbapolin Inhibitors

et al. 2023

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“…REPLACE was applied to accelerate the conversion of FLIP to be a nonpeptide PBD inhibitor. 4-Alkylbenzamide derivatives 55 and 56 were identified as lead compounds with reasonable PLK1 PBD inhibitory activity (Figure A). , The carboxylic acid moiety of 55 was a bioisostere of the phosphate group and was important for maintaining the inhibitory activity against the PLK1 PBD. The alkyl chain occupied the hydrophobic groove of the PBD.…”

Section: Recent Progress In Plk1i Development For Cancer Therapymentioning

confidence: 99%

Polo-like Kinase 1 Inhibitors in Human Cancer Therapy: Development and Therapeutic Potential

Zhang

Wang

et al. 2022

J. Med. Chem.

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Polo-like kinase 1 (PLK1) plays an important role in a variety of cellular functions, including the regulation of mitosis, DNA replication, autophagy, and the epithelial–mesenchymal transition (EMT). PLK1 overexpression is often associated with cell proliferation and poor prognosis in cancer patients, making it a promising antitumor target. To date, at least 10 PLK1 inhibitors (PLK1i) have been entered into clinical trials, among which the typical kinase domain (KD) inhibitor BI 6727 (volasertib) was granted “breakthrough therapy designation” by the FDA in 2013. Unfortunately, many other KD inhibitors showed poor specificity, resulting in dose-limiting toxicity, which has greatly impeded their development. Researchers recently discovered many PLK1i with higher selectivity, stronger potency, and better absorption, distribution, metabolism, and elimination (ADME) characteristics. In this review, we emphasize the structure–activity relationships (SARs) of PLK1i, providing insights into new drugs targeting PLK1 for antitumor clinical practice.

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“…Also, 1-thioxo-2,4-dihydro-[1,2,4]triazolo[4,3- a ]quinazolin-5(1 H )-one derivatives have been reported to potently and selectively inhibit Plk1-PBD . Interestingly, it was recently reported that abbapolins, nonpeptidic Plk1 binding inhibitors, induce Plk1 degradation in prostate cancer cells . However, extensive high-throughput screening has failed to identify PBD-targeting compounds that have high potency and specificity …”

Section: Introductionmentioning

confidence: 99%

Novel Macrocyclic Peptidomimetics Targeting the Polo-Box Domain of Polo-Like Kinase 1

et al. 2022

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The polo-box domain (PBD) of Plk1 is a promising target for cancer therapeutics. We designed and synthesized novel phosphorylated macrocyclic peptidomimetics targeting PBD based on acyclic phosphopeptide PMQSpTPL. The inhibitory activities of 16e on Plk1-PBD is >30-fold higher than those of PMQSpTPL. Both 16a and 16e possess excellent selectivity for Plk1-PBD over Plk2/3-PBD. Analysis of the cocrystal structure of Plk1-PBD in complex with 16a reveals that the 3-(trifluoromethyl)benzoyl group in 16a interacts with Arg516 through a π-stacking interaction. This π-stacking interaction, which has not been reported previously, provides insight into the design of novel and potent Plk1-PBD inhibitors. Furthermore, 16h, a PEGlyated macrocyclic phosphopeptide derivative, induces Plk1 delocalization and mitotic failure in HeLa cells. Also, the number of phospho-H3-positive cells in a zebrafish embryo increases in proportion to the amount of 16a. Collectively, the novel macrocyclic peptidomimetics should serve as valuable templates for the design of potent and novel Plk1-PBD inhibitors.

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Nonpeptidic, Polo-Box Domain-Targeted Inhibitors of PLK1 Block Kinase Activity, Induce Its Degradation and Target-Resistant Cells

Cited by 13 publications

References 49 publications

Structural Basis for Variations in Polo-like Kinase 1 Conformation and Intracellular Stability Induced by ATP-Competitive and Novel Noncompetitive Abbapolin Inhibitors

Structural Basis for Variations in Polo-like Kinase 1 Conformation and Intracellular Stability Induced by ATP-Competitive and Novel Noncompetitive Abbapolin Inhibitors

Polo-like Kinase 1 Inhibitors in Human Cancer Therapy: Development and Therapeutic Potential

Novel Macrocyclic Peptidomimetics Targeting the Polo-Box Domain of Polo-Like Kinase 1

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