Phosphorylation of Capsaicinoid Derivatives Provides Highly Potent and Selective Inhibitors of the Transcription Factor STAT5b

Elumalai, Nagarajan; Berg, Angela; Rubner, Stefan; Berg, Thorsten

doi:10.1021/acschembio.5b00817

Cited by 19 publications

(20 citation statements)

References 34 publications

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“…In cells, the pivaloyloxymethyl groups of 8 are cleaved off by intracellular esterases, thereby releasing the parent compound, along with formaldehyde and pivalic acid. Because commercially available antibodies do not allow for distinction between STAT5a phosphorylated at Tyr694 and STAT5b phosphorylated at Tyr699, we used an assay system based on fusion proteins of the individual STAT5 proteins with GFP, which are also recognized by anti-phospho-STAT5 antibodies, but can be distinguished from endogenous STAT5 by their higher molecular weight 15, 16 . Treatment of STAT5b-GFP-transfected K562 cells, in which STAT5 proteins are constitutively activated by Bcr-Abl, with 8 resulted in a dose-dependent decrease in phosphorylation at STAT5b Tyr699, with an IC 50 of 1.5 µM (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…S4). 8 is 2.5-fold more active against STAT5b phosphorylation than the pivaloyloxymethylesters of 2 (IC 50 = 3.8 µM) 15 and of Capstafin 16 (IC 50 = 4.1 µM) (Supplementary Fig. S5).…”

Section: Resultsmentioning

confidence: 99%

“…We recently presented catechol bisphosphate ( 1 , Fig. 1a) and its derivatives Stafib-1 ( 2 , Table 1) 15 and Capstafin 16 as selective inhibitors of the STAT5b SH2 domain.

Figure 1Binding of catechol bisphosphate ( 1 ) to the STAT5b SH2 domain. ( a ) Chemical structure of 1 .…”

Section: Introductionmentioning

confidence: 99%

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Rational development of Stafib-2: a selective, nanomolar inhibitor of the transcription factor STAT5b

Elumalai

Berg

Rubner

et al. 2017

Sci Rep

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The transcription factor STAT5b is a target for tumour therapy. We recently reported catechol bisphosphate and derivatives such as Stafib-1 as the first selective inhibitors of the STAT5b SH2 domain. Here, we demonstrate STAT5b binding of catechol bisphosphate by solid-state nuclear magnetic resonance, and report on rational optimization of Stafib-1 (Ki = 44 nM) to Stafib-2 (Ki = 9 nM). The binding site of Stafib-2 was validated using combined isothermal titration calorimetry (ITC) and protein point mutant analysis, representing the first time that functional comparison of wild-type versus mutant protein by ITC has been used to characterize the binding site of a small-molecule ligand of a STAT protein with amino acid resolution. The prodrug Pomstafib-2 selectively inhibits tyrosine phosphorylation of STAT5b in human leukaemia cells and induces apoptosis in a STAT5-dependent manner. We propose Pomstafib-2, which currently represents the most active, selective inhibitor of STAT5b activation available, as a chemical tool for addressing the fundamental question of which roles the different STAT5 proteins play in various cell processes.

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Section: Resultsmentioning

confidence: 99%

“…S4). 8 is 2.5-fold more active against STAT5b phosphorylation than the pivaloyloxymethylesters of 2 (IC 50 = 3.8 µM) 15 and of Capstafin 16 (IC 50 = 4.1 µM) (Supplementary Fig. S5).…”

Section: Resultsmentioning

confidence: 99%

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Rational development of Stafib-2: a selective, nanomolar inhibitor of the transcription factor STAT5b

Elumalai

Berg

Rubner

et al. 2017

Sci Rep

Self Cite

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“…FOXC1 is a member of the Forkhead box family transcription factors and is known to promote melanoma by activating the MST1R/PI3K/ AKT pathway (45). Although transcription factors have traditionally been considered undruggable targets, recent successes in this arena call this into question (46)(47)(48)(49). Taken together, these data suggest that pharmacologic targeting of transcription factors upregulated in ATC (KLF16, SP3, ETV6, and FOXC1) might be an area for future investigations in developing novel ATC therapeutics.…”

Section: Discussionmentioning

confidence: 96%

Cell Cycle M-Phase Genes Are Highly Upregulated in Anaplastic Thyroid Carcinoma

Weinberger

Ponny

et al. 2017

Thyroid

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Background: Anaplastic thyroid carcinoma (ATC) accounts for only 3% of thyroid cancers, yet strikingly, it accounts for almost 40% of thyroid cancer deaths. Currently, no effective therapies exist. In an effort to identify ATC-specific therapeutic targets, we analyzed global gene expression data from multiple studies to identify ATC-specific dysregulated genes. Methods: The National Center for Biotechnology Information Gene Expression Omnibus database was searched for high-throughput gene expression microarray studies from human ATC tissue along with normal thyroid and/or papillary thyroid cancer (PTC) tissue. Gene expression levels in ATC were compared with normal thyroid or PTC using seven separate comparisons, and an ATC-specific gene set common in all seven comparisons was identified. We investigated these genes for their biological functions and pathways. Results: There were three studies meeting inclusion criteria, (including 32 ATC patients, 69 PTC, and 75 normal). There were 259 upregulated genes and 286 downregulated genes in ATC with at least two-fold change in all seven comparisons. Using a five-fold filter, 36 genes were upregulated in ATC, while 40 genes were downregulated. Of the 10 top globally upregulated genes in ATC, 4/10 (MMP1, ANLN, CEP55, and TFPI2) are known to play a role in ATC progression; however, 6/10 genes (TMEM158, CXCL5, E2F7, DLGAP5, MME, and ASPM) had not been specifically implicated in ATC. Similarly, 3/10 (SFTA3, LMO3, and C2orf40) of the most globally downregulated genes were novel in this context, while 7/10 genes (SLC26A7, TG, TSHR, DUOX2, CDH1, PDE8B, and FOXE1) have been previously identified in ATC. We experimentally validated a significant correlation for seven transcription factors (KLF16, SP3, ETV6, FOXC1, SP1, EGFR1, and MAFK) with the ATC-specific genes using microarray analysis of ATC cell lines. Ontology clustering of globally altered genes revealed that ''mitotic cell cycle'' is highly enriched in the globally upregulated gene set (44% of top upregulated genes, p-value <10 -30 ). Conclusions: By focusing on globally altered genes, we have identified a set of consistently altered biological processes and pathways in ATC. Our data are consistent with an important role for M-phase cell cycle genes in ATC, and may provide direction for future studies to identify novel therapeutic targets for this disease.

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“…Berg and co-workers reported nonpeptidic chromone-based compounds (STAT5i) that directly targeted the SH2 domain of STAT5 and selectively disrupted the STAT5 SH2 domain-phosphorylated tyrosine interaction over that of STAT1/3, leading an inhibition of STAT5/DNA binding in K562 nuclear extracts17. Recently, a potent molecule derived from the natural product-dihydrocapsaicin inhibited the SH2 domain of STAT5B, with 35-fold selectivity over STAT5A18. However, to date, no direct STAT5B inhibitors have entered into clinical trials.…”

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confidence: 99%

Antagonizing STAT5B dimerization with an osmium complex

Liu

Wang

Kang

et al. 2016

Sci Rep

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Targeting STAT5 is an appealing therapeutic strategy for the treatment of hematologic malignancies and inflammation. Here, we present the novel osmium(II) complex 1 as the first metal-based inhibitor of STAT5B dimerization. Complex 1 exhibited superior inhibitory activity against STAT5B DNA binding compared to STAT5A DNA binding. Moreover, 1 repressed STAT5B transcription and blocked STAT5B dimerization via binding to the STAT5B protein, thereby inhibiting STAT5B translocation to the nucleus. Furthermore, 1 was able to selectively inhibit STAT5B phosphorylation without affecting the expression level of STAT5B.

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Phosphorylation of Capsaicinoid Derivatives Provides Highly Potent and Selective Inhibitors of the Transcription Factor STAT5b

Cited by 19 publications

References 34 publications

Rational development of Stafib-2: a selective, nanomolar inhibitor of the transcription factor STAT5b

Rational development of Stafib-2: a selective, nanomolar inhibitor of the transcription factor STAT5b

Cell Cycle M-Phase Genes Are Highly Upregulated in Anaplastic Thyroid Carcinoma

Antagonizing STAT5B dimerization with an osmium complex

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