PROTAC-mediated crosstalk between E3 ligases

2019 ◽  
Vol 55 (12) ◽  
pp. 1821-1824 ◽  
Author(s):  
Christian Steinebach ◽  
Hannes Kehm ◽  
Stefanie Lindner ◽  
Lan Phuong Vu ◽  
Simon Köpff ◽  
...  
Keyword(s):  
Small Molecule ◽  
E3 Ligases ◽  
Protein Levels ◽  
Control Protein ◽  
Research Tools

Small-molecule heterobifunctional degraders can effectively control protein levels and are useful research tools.

scholarly journals Targeting the Ubiquitin-Proteasome System for Cancer Therapeutics by Small-Molecule Inhibitors

Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 3079
Author(s):  
Gabriel LaPlante ◽  
Wei Zhang
Keyword(s):  
Protein Degradation ◽  
Small Molecule ◽  
Small Molecule Inhibitors ◽  
Proteasome Inhibitors ◽  
Cancer Therapeutics ◽  
Ubiquitin Proteasome System ◽  
Cellular Protein ◽  
E3 Ligases ◽  
Protein Levels ◽  
Ubiquitin Proteasome

The ubiquitin-proteasome system (UPS) is a critical regulator of cellular protein levels and activity. It is, therefore, not surprising that its dysregulation is implicated in numerous human diseases, including many types of cancer. Moreover, since cancer cells exhibit increased rates of protein turnover, their heightened dependence on the UPS makes it an attractive target for inhibition via targeted therapeutics. Indeed, the clinical application of proteasome inhibitors in treatment of multiple myeloma has been very successful, stimulating the development of small-molecule inhibitors targeting other UPS components. On the other hand, while the discovery of potent and selective chemical compounds can be both challenging and time consuming, the area of targeted protein degradation through utilization of the UPS machinery has seen promising developments in recent years. The repertoire of proteolysis-targeting chimeras (PROTACs), which employ E3 ligases for the degradation of cancer-related proteins via the proteasome, continues to grow. In this review, we will provide a thorough overview of small-molecule UPS inhibitors and highlight advancements in the development of targeted protein degradation strategies for cancer therapeutics.

scholarly journals Targeted Protein Degradation via a Covalent Reversible Degrader Based on Bardoxolone

2020 ◽  
Author(s):  
Bingqi Tong ◽  
Mai Luo ◽  
Yi Xie ◽  
Jessica Spradlin ◽  
John A. Tallarico ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Protein Binding ◽  
Protein Degradation ◽  
Small Molecules ◽  
Small Molecule ◽  
E3 Ligase ◽  
E3 Ligases ◽  
Protein Levels ◽  
Nrf2 Activator

<p>Targeted protein degradation (TPD) has emerged as a powerful tool in drug discovery for the perturbation of protein levels using heterobifunctional small molecules (i.e. PROTACs). E3 ligase recruiters remain central to this process yet relatively few have been identified relative to the >500 predicted human E3 ligases. While, initial recruiters have utilized non-covalent chemistry for protein binding, very recently covalent engagement to novel E3’s has proven fruitful in TPD application. Herein we demonstrate efficient proteasome-mediated degradation of BRD4 by a bifunctional small molecule linking the KEAP1-NRF2 activator bardoxolone to a BRD4 inhibitor JQ1. Notably, this work reports the first covalent, reversible E3 ligase recruiter for TPD applications. </p>

scholarly journals Targeted Protein Degradation via a Covalent Reversible Degrader Based on Bardoxolone

2020 ◽  
Author(s):  
Bingqi Tong ◽  
Mai Luo ◽  
Yi Xie ◽  
Jessica Spradlin ◽  
John A. Tallarico ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Protein Binding ◽  
Protein Degradation ◽  
Small Molecules ◽  
Small Molecule ◽  
E3 Ligase ◽  
E3 Ligases ◽  
Protein Levels ◽  
Nrf2 Activator

<p>Targeted protein degradation (TPD) has emerged as a powerful tool in drug discovery for the perturbation of protein levels using heterobifunctional small molecules (i.e. PROTACs). E3 ligase recruiters remain central to this process yet relatively few have been identified relative to the >500 predicted human E3 ligases. While, initial recruiters have utilized non-covalent chemistry for protein binding, very recently covalent engagement to novel E3’s has proven fruitful in TPD application. Herein we demonstrate efficient proteasome-mediated degradation of BRD4 by a bifunctional small molecule linking the KEAP1-NRF2 activator bardoxolone to a BRD4 inhibitor JQ1. Notably, this work reports the first covalent, reversible E3 ligase recruiter for TPD applications. </p>

scholarly journals Bardoxolone conjugation enables targeted protein degradation of BRD4

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Bingqi Tong ◽  
Mai Luo ◽  
Yi Xie ◽  
Jessica N. Spradlin ◽  
John A. Tallarico ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Protein Binding ◽  
Protein Degradation ◽  
Small Molecules ◽  
Small Molecule ◽  
E3 Ligase ◽  
E3 Ligases ◽  
Protein Levels ◽  
Nrf2 Activator

Abstract Targeted protein degradation (TPD) has emerged as a powerful tool in drug discovery for the perturbation of protein levels using heterobifunctional small molecules. E3 ligase recruiters remain central to this process yet relatively few have been identified relative to the ~ 600 predicted human E3 ligases. While, initial recruiters have utilized non-covalent chemistry for protein binding, very recently covalent engagement to novel E3’s has proven fruitful in TPD application. Herein we demonstrate efficient proteasome-mediated degradation of BRD4 by a bifunctional small molecule linking the KEAP1-Nrf2 activator bardoxolone to a BRD4 inhibitor JQ1.

scholarly journals Pirh2, an E3 ligase, regulates the AIP4–p73 regulatory pathway by modulating AIP4 expression and ubiquitination

2021 ◽  
Author(s):  
Rami Abou Zeinab ◽  
H Helena Wu ◽  
Yasser Abuetabh ◽  
Sarah Leng ◽  
Consolato Sergi ◽  
...  
Keyword(s):  
Regulatory Protein ◽  
Ectopic Expression ◽  
E3 Ligase ◽  
Regulatory Pathway ◽  
Hect Domain ◽  
E3 Ligases ◽  
Multiple Substrates ◽  
Protein Levels ◽  
Cycle Arrest ◽  
Negative Regulatory Pathway

Abstract Pirh2 is an E3 ligase belonging to the RING-H2 family and shown to bind, ubiquitinate and downregulate p73 tumor suppressor function without altering p73 protein levels. AIP4, an E3 ligase belonging to the HECT domain family, has been reported to be a negative regulatory protein that promotes p73 ubiquitination and degradation. Herein, we found that Pirh2 is a key regulator of AIP4 that inhibits p73 function. Pirh2 physically interacts with AIP4 and significantly downregulates AIP4 expression. This downregulation is shown to involve the ubiquitination of AIP4 by Pirh2. Importantly, we demonstrated that the ectopic expression of Pirh2 inhibits the AIP4–p73 negative regulatory pathway, which was restored when depleting endogenous Pirh2 utilizing Pirh2-siRNAs. We further observed that Pirh2 decreases AIP4-mediated p73 ubiquitination. At the translational level and specifically regarding p73 cell cycle arrest function, Pirh2 still ensures the arrest of p73-mediated G1 despite AIP4 expression. Our study reveals a novel link between two E3 ligases previously thought to be unrelated in regulating the same effector substrate, p73. These findings open a gateway to explain how E3 ligases differentiate between regulating multiple substrates that may belong to the same family of proteins, as it is the case for the p53 and p73 proteins.

High-Throughput Screening to Identify Small Molecules That Selectively Inhibit APOL1 Protein Level in Podocytes

2021 ◽  
pp. 247255522110262
Author(s):  
Jonathan Choy ◽  
Yanqing Kan ◽  
Steve Cifelli ◽  
Josephine Johnson ◽  
Michelle Chen ◽  
...  
Keyword(s):  
Small Molecule ◽  
High Throughput ◽  
High Throughput Screening ◽  
Screening Strategy ◽  
Time Resolved ◽  
Protein Levels ◽  
Increased Risk ◽  
Compound Screening ◽  
High Throughput Screens ◽  
Screening Library

High-throughput phenotypic screening is a key driver for the identification of novel chemical matter in drug discovery for challenging targets, especially for those with an unclear mechanism of pathology. For toxic or gain-of-function proteins, small-molecule suppressors are a targeting/therapeutic strategy that has been successfully applied. As with other high-throughput screens, the screening strategy and proper assays are critical for successfully identifying selective suppressors of the target of interest. We executed a small-molecule suppressor screen to identify compounds that specifically reduce apolipoprotein L1 (APOL1) protein levels, a genetically validated target associated with increased risk of chronic kidney disease. To enable this study, we developed homogeneous time-resolved fluorescence (HTRF) assays to measure intracellular APOL1 and apolipoprotein L2 (APOL2) protein levels and miniaturized them to 1536-well format. The APOL1 HTRF assay served as the primary assay, and the APOL2 and a commercially available p53 HTRF assay were applied as counterscreens. Cell viability was also measured with CellTiter-Glo to assess the cytotoxicity of compounds. From a 310,000-compound screening library, we identified 1490 confirmed primary hits with 12 different profiles. One hundred fifty-three hits selectively reduced APOL1 in 786-O, a renal cell adenocarcinoma cell line. Thirty-one of these selective suppressors also reduced APOL1 levels in conditionally immortalized human podocytes. The activity and specificity of seven resynthesized compounds were validated in both 786-O and podocytes.

scholarly journals Attenuation of Zinc Finger Nuclease Toxicity by Small-Molecule Regulation of Protein Levels

PLoS Genetics ◽  
2009 ◽  
Vol 5 (2) ◽  
pp. e1000376 ◽  
Author(s):  
Shondra M. Pruett-Miller ◽  
David W. Reading ◽  
Shaina N. Porter ◽  
Matthew H. Porteus
Keyword(s):  
Zinc Finger ◽  
Small Molecule ◽  
Zinc Finger Nuclease ◽  
Protein Levels

scholarly journals Tunable protein synthesis by transcript isoforms in human cells

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Stephen N Floor ◽  
Jennifer A Doudna
Keyword(s):  
Translational Control ◽  
Protein Production ◽  
Dynamic Range ◽  
Human Cells ◽  
Untranslated Regions ◽  
Specific Expression ◽  
Transcript Isoforms ◽  
Protein Levels ◽  
Eukaryotic Genes ◽  
Control Protein

Eukaryotic genes generate multiple RNA transcript isoforms though alternative transcription, splicing, and polyadenylation. However, the relationship between human transcript diversity and protein production is complex as each isoform can be translated differently. We fractionated a polysome profile and reconstructed transcript isoforms from each fraction, which we term Transcript Isoforms in Polysomes sequencing (TrIP-seq). Analysis of these data revealed regulatory features that control ribosome occupancy and translational output of each transcript isoform. We extracted a panel of 5′ and 3′ untranslated regions that control protein production from an unrelated gene in cells over a 100-fold range. Select 5′ untranslated regions exert robust translational control between cell lines, while 3′ untranslated regions can confer cell type-specific expression. These results expose the large dynamic range of transcript-isoform-specific translational control, identify isoform-specific sequences that control protein output in human cells, and demonstrate that transcript isoform diversity must be considered when relating RNA and protein levels.

scholarly journals A beacon in the cytoplasm: Tracking translation of single mRNAs

2016 ◽  
Vol 214 (6) ◽  
pp. 649-652 ◽  
Author(s):  
Hema V. Pingali ◽  
Angela K. Hilliker
Keyword(s):  
Real Time ◽  
New Technique ◽  
Real Time Monitoring ◽  
Protein Levels ◽  
Cell Biol ◽  
A New Technique ◽  
Control Protein

Translation is carefully regulated to control protein levels and allow quick responses to changes in the environment. Certain questions about translation in vivo have been unattainable until now. In this issue, Pichon et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201605024) describe a new technique to allow real-time monitoring of translation on single mRNAs.

scholarly journals Screening antiproliferative drug for breast cancer from bisbenzylisoquinoline alkaloid tetrandrine and fangchinoline derivatives by targeting BLM helicase

BMC Cancer ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Wangming Zhang ◽  
Shuang Yang ◽  
Jinhe Liu ◽  
Linchun Bao ◽  
He Lu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Dna Binding ◽  
Small Molecules ◽  
Cancer Cells ◽  
Small Molecule ◽  
Breast Cancer Cells ◽  
Dna Unwinding ◽  
Protein Levels ◽  
Blm Helicase ◽  
Bisbenzylisoquinoline Alkaloids

Abstract Background The high expression of BLM (Bloom syndrome) helicase in tumors involves its strong association with cell expansion. Bisbenzylisoquinoline alkaloids own an antitumor property and have developed as candidates for anticancer drugs. This paper aimed to screen potential antiproliferative small molecules from 12 small molecules (the derivatives of bisbenzylisoquinoline alkaloids tetrandrine and fangchinoline) by targeting BLM642–1290 helicase. Then we explore the inhibitory mechanism of those small molecules on proliferation of MDA-MB-435 breast cancer cells. Methods Fluorescence polarization technique was used to screen small molecules which inhibited the DNA binding and unwinding of BLM642–1290 helicase. The effects of positive small molecules on the ATPase and conformation of BLM642–1290 helicase were studied by the malachite green-phosphate ammonium molybdate colorimetry and ultraviolet spectral scanning, respectively. The effects of positive small molecules on growth of MDA-MB-435 cells were studied by MTT method, colony formation and cell counting method. The mRNA and protein levels of BLM helicase in the MDA-MB-435 cells after positive small molecule treatments were examined by RT-PCR and ELISA, respectively. Results The compound HJNO (a tetrandrine derivative) was screened out which inhibited the DNA binding, unwinding and ATPase of BLM642–1290 helicase. That HJNO could bind BLM642–1290helicase to change its conformationcontribute to inhibiting the DNA binding, ATPase and DNA unwinding of BLM642–1290 helicase. In addition, HJNO showed its inhibiting the growth of MDA-MB-435 cells. The values of IC50 after drug treatments for 24 h, 48 h and 72 h were 19.9 μmol/L, 4.1 μmol/L and 10.9 μmol/L, respectively. The mRNA and protein levels of BLM helicase in MDA-MB-435 cells increased after HJNO treatment. Those showed a significant difference (P < 0.05) compared with negative control when the concentrations of HJNO were 5 μmol/L and 10 μmol/L, which might contribute to HJNO inhibiting the DNA binding, ATPase and DNA unwinding of BLM helicase. Conclusion The small molecule HJNO was screened out by targeting BLM642–1290 helicase. And it showed an inhibition on MDA-MB-435 breast cancer cells expansion.

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