Evaluation of quantitative assays for the identification of direct signal transducer and activator of transcription 3 (STAT3) inhibitors

Furtek, Steffanie L.; Matheson, Christopher J.; Backos, Donald S.; Reigan, Philip

doi:10.18632/oncotarget.12868

Cited by 21 publications

(32 citation statements)

References 41 publications

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“…16 In commonly used STAT3 inhibition assays, (including the fluorescence polarization (FP) assay, electrophoretic mobility shift assay (EMSA) and ELISAs), reactive compounds that chemically modify STAT3 to impair its stability or binding interactions would induce the same response as potent but non-reactive STAT3 inhibitors (described in Figure 1B). 12 When used in cell-based assays, these reactive compounds may non-specifically alkylate cellular components to induce toxicity. A particularly hazardous manifestation of this would be in cancer cell proliferation assays where reactive compounds (that show inhibitory activity in traditional in vitro STAT3 assays) would inhibit cancer cell proliferation and could modify cell signaling networks because of their inherent toxicity, and not necessarily because they bind selectively to STAT3 or another protein of interest.…”

Section: Introductionmentioning

confidence: 99%

STAT3 differential scanning fluorimetry and differential scanning light scattering assays: Addressing a missing link in the characterization of STAT3 inhibitor interactions

Desroses

Busker

Astorga‐Wells

et al. 2018

Journal of Pharmaceutical and Biomedical Analysis

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STAT3 protein is an established target for the development of new cancer therapeutic agents. Despite lacking a traditional binding site for small molecule inhibitors, many STAT3 inhibitors have been identified and explored for their anti-cancer activity. Because STAT3 signaling is mediated by protein-protein interactions, indirect methods are often employed to determine if proposed STAT3 inhibitors bind to STAT3 protein. While established STAT3 inhibition assays (such as the fluorescence polarization assay, electrophoretic mobility shift assay and ELISAs) have been used to identify novel inhibitors of STAT3 signaling, methods that directly assess STAT3 protein-inhibitor interactions could facilitate the development of novel inhibitors. In this context, we herein report new STAT3 binding assays based on differential scanning fluorimetry (DSF) and differential scanning light scattering (DSLS) to characterize interactions between STAT3 protein and inhibitors. Several peptide and small molecule STAT3 inhibitors have been evaluated, and new insight into how these compounds may interact with STAT3 is provided.

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Section: Introductionmentioning

confidence: 99%

STAT3 differential scanning fluorimetry and differential scanning light scattering assays: Addressing a missing link in the characterization of STAT3 inhibitor interactions

Desroses

Busker

Astorga‐Wells

et al. 2018

Journal of Pharmaceutical and Biomedical Analysis

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“…Niclosamide has been identified as a direct STAT3 inhibitor through interaction with the DNA-binding domain (37). In addition to its role in STAT3 inhibition, niclosamide has also been revealed to concurrently inhibit multiple intracellular signaling pathways, including the Wnt, Notch 1, mTOR and NF-κB signaling cascades (10,45).…”

Section: Discussionmentioning

confidence: 99%

“…The molecular mechanisms underlying the antineoplastic effect of niclosamide have been explored in many human malignant cancers, indicating that niclosamide exhibits anticancer activity by suppressing many oncogenic signaling pathways concurrently (7,13,17,23,27,28,30,36). For instance, niclosamide has been identified as a direct inhibitor of signal transducer and activator of transcription 3 (STAT3) through interaction with the DNA-binding domain (37). In ovarian cancer, niclosamide significantly decreased the expression of proteins in the wingless/integrated (Wnt), mammalian target of rapamycin (mTOR) and STAT3 pathways and caused significant inhibition of proliferation of cells (28).…”

Section: Introductionmentioning

confidence: 99%

Niclosamide inhibits the cell proliferation and enhances the responsiveness of esophageal cancer cells to chemotherapeutic agents

Lee¹,

Chen

Hsu

et al. 2019

Oncol Rep

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Niclosamide is an FDA-approved anthelmintic drug, and may elicit antineoplastic effects through direct STAT3 inhibition, which has been revealed in numerous human cancer cells. Chemotherapy is the standard treatment for advanced esophageal cancers, but also causes severe systemic side effects. The present study represents the first study evaluating the anticancer efficacy of niclosamide in esophageal cancers. Through western blot assay, it was demonstrated that niclosamide suppressed the STAT3 signaling pathway in esophageal adenocarcinoma cells (BE3) and esophageal squamous cell carcinoma cells (CE48T and CE81T). In addition, niclosamide inhibited cell proliferation as determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and soft agar colony forming assay, and induced cell apoptosis as determined by Annexin V and PI staining. The induction of p21 and G1 arrest of the cell cycle also was revealed in niclosamide-treated CE81T cells by qPCR and flow cytometric assays, respectively. Furthermore, in the combination analysis of niclosamide and chemotherapeutic agents by MTS assay, low IC 50 values were detected in cells co-treated with niclosamide, with the exception of cisplatin-treated CE81T cells. To confirm the results using an apoptosis assay, the apoptotic enhancement of niclosamide was only demonstrated in CE48T cells co-treated with 5-FU, cisplatin, or paclitaxel, and in BE3 cells co-treated with paclitaxel, but not in CE81T cells. These findings indicate a future clinical application of niclosamide in esophageal cancers.

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“…inhibitors have been considered as novel modes of cancer therapy (18,19). For thousands of years, a well-known Chinese plant, Salvia miltiorrhiza (Danshen), has been used to treat cardiovascular (20), gastrointestinal (21), circulatory (22) and neurological (22) diseases.…”

Section: Introductionmentioning

confidence: 99%

“…Although STAT3 proteins are known to be ubiquitous in cells and found in the cytoplasm and mitochondrion, it is not known how the expression of STAT3 in different cancer cells can influence CT anticancer activity(11,16).STAT3 signaling activation stimulates transcription of different oncogenes that will perpetuate cell proliferation, cell survival and resistance to apoptosis(56). Therefore, CT ability to bind to STAT3 proteins will impede STAT3 phosphorylation and subsequently STAT3 signaling activation(19). Data obtained from this in vitro study using alive-cell imaging-based assay showed that CT at 20 M concentration was able to induce cell death in various human and canine cancer cell lines.…”

mentioning

confidence: 99%

Comprehensive Live-cell Imaging Analysis of Cryptotanshinone and Synergistic Drug-Screening Effects in Various Human and Canine Cancer Cell Lines

Wilson-Robles

Bittner

Lopes

et al. 2020

Preprint

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ABSTRACTBackgroundSeveral studies have highlighted both the extreme anticancer effects of Cryptotanshinone (CT), a Stat3 crippling component from Salvia miltiorrhiza, as well as other STAT3 inhibitors to fight cancer.MethodsData presented in this experiment incorporates 2 years of in vitro studies applying a comprehensive live-cell drug-screening analysis of human and canine cancer cells exposed to CT at 20 μM concentration, as well as to other drug combinations. As previously observed in other studies, dogs are natural cancer models, given to their similarity in cancer genetics, epidemiology and disease progression compared to humans.ResultsResults obtained from several types of human and canine cancer cells exposed to CT and varied drug combinations, verified CT efficacy at combating cancer by achieving an extremely high percentage of apoptosis within 24 hours of drug exposure.ConclusionsCT anticancer efficacy in various human and canine cancer cell lines denotes its ability to interact across different biological processes and cancer regulatory cell networks, driving inhibition of cancer cell survival.

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Evaluation of quantitative assays for the identification of direct signal transducer and activator of transcription 3 (STAT3) inhibitors

Cited by 21 publications

References 41 publications

STAT3 differential scanning fluorimetry and differential scanning light scattering assays: Addressing a missing link in the characterization of STAT3 inhibitor interactions

STAT3 differential scanning fluorimetry and differential scanning light scattering assays: Addressing a missing link in the characterization of STAT3 inhibitor interactions

Niclosamide inhibits the cell proliferation and enhances the responsiveness of esophageal cancer cells to chemotherapeutic agents

Comprehensive Live-cell Imaging Analysis of Cryptotanshinone and Synergistic Drug-Screening Effects in Various Human and Canine Cancer Cell Lines

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