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Stat3 inhibitors

Inactive Publication Date: 2011-12-22
BAYLOR COLLEGE OF MEDICINE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0010]In some embodiments of the invention, the methods and / or compositions of the invention are useful for inhibiting Stat3 activity. In specific cases, the methods and / or compositions of the invention are employed to induce apoptosis in a cancer cell, inhibit angiogenesis in a tumor, enhance anti-tumor immune-mediated cytotoxicity, decrease tumor growth, improve animal survival, inhibit Stat3 phosphorylation and / or nuclear-to-cytoplasmic translocation of Stat3. In certain embodiments, Stat3 inhibitors inhibit Stat3 but fail to inhibit Stat1. In some embodiments, Stat3 inhibitors of the invention interact with the Stat3 SH2 domain, competitively inhibit recombinant Stat3 binding to its immobilized pY-peptide ligand, and / or inhibit IL-6-mediated tyrosine phosphorylation of Stat3, for example. In particular, the Stat3 inhibitor of the invention fulfills the criteria of interaction analysis (CIA): 1) global minimum energy score ≦−30; 2) formation of a salt-bridge and / or H-bond network within the pY-residue binding site of Stat3; and / or 3) formation of a H-bond with or blocking access to the amide hydrogen of E638 of Stat3, for example. In some embodiments, the Stat3 inhibitor interacts with a hydrophobic binding pocket with the Stat3 SH2 domain.

Problems solved by technology

However, determination of their selectivity was established empirically after their identification as Stat3 inhibitors and was not built into the screening process.

Method used

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example 1

Exemplary Materials and Methods

[0120]Virtual ligand screening. The inventors isolated the three-dimensional structure of the Stat3 SH2 domain from the core fragment structure of phosphorylated Stat3 homodimers bound to DNA (Becker et al., 1998) deposited in the RCSB Protein Data Bank (PDB) databank (PDB code 1BG1) and converted it to be an Internal Coordinate Mechanics (ICM)-compatible system by adding hydrogen atoms, modifying unusual amino acids, making charge adjustments and performing additional cleanup steps. In addition, the inventors retrieved the coordinates of the Stat1 SH2 domain from the PDB databank (PDB code 1BF5) for use in computational selectivity analysis (Chen et al., 1998). Commercial chemical databases (Chembridge, Asinex, ChemDiv, Enamine, Keyorganics and Life Chemicals) were chosen as sources of compounds for screening in silico. Selection was of the amide hydrogen of E638 within the site that binds the +3 residue (Q, C or T) within the pY-peptide ligand (Shao ...

example 2

Identification by VLS of Compounds that Blocked STAT3 Binding to its Phosphopeptide Ligand and Inhibited IL-6-Mediated Phosphorylation of STAT3

[0128]The VLS protocol was used to evaluate a total of 920,000 drug-like compounds. Of these, 142 compounds fulfilled CIA criteria. These compounds were purchased and tested for their ability to block Stat3 binding to its phosphopeptide ligand in a surface plasmon resonance (SPR)-based binding assay and to inhibit IL-6-mediated phosphorylation of Stat3. SPR competition experiments showed that of the 142 compounds tested, 3 compounds—Cpd3, Cpd30 and Cpd188—were able to directly compete with pY-peptide for binding to Stat3 with IC50 values of 447, 30, and 20 μM, respectively (FIGS. 1 and 3; Table 4).

TABLE 4IC50 values (μM) of 6 active compoundsAssayCpd3Cpd30Cpd188Cpd3-2Cpd3-7Cpd30-12SPR 44713020256137114pStat3 9118731446360HTM131773915020>3001Data presented are the mean or mean ± SD;ND = not determined.

[0129]In addition, each compound inhibited...

example 3

Compound-Mediated Inhibition of Ligand-Stimulated Phosphorylation of STAT3 is Specific for STAT3 vs. STAT1

[0131]While Stat3 contributes to oncogenesis, in part, through inhibition of apoptosis, Stat1 is anti-oncogenic; it mediates the apoptotic effects of interferons and contributes to tumor surveillance (Kaplan et al., 1998; Ramana et al., 2000). Consequently, compounds that target Stat3 while sparing Stat1, leaving its anti-oncogenic functions unopposed, may result in a synergistic anti-tumor effect. To assess the selectivity of the compounds for Stat3 vs. Stat1, HepG2 cells were incubated with Cpd3, Cpd30, Cpd188, Cpd3-2, Cpd3-7, and Cpd30-12 (300 μM) for 1 hour at 37° C. before IFN-γ stimulation (FIG. 4). Only treatment with Cpd30-12 blocked Stat1 phosphorylation while each of the other five compounds—Cpd3, Cpd30, Cpd188, Cpd3-2 and Cpd3-7—did not. Thus, five of the six exemplary compounds identified were selective and inhibited ligand-stimulated phosphorylation of Stat3 but not...

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Abstract

Small molecule inhibitors of Stat3 and their derivatives are disclosed. Also described are methods to inhibit cell growth by use of Stat3 inhibitors, and the use of Stat3 inhibitors for the prevention and / or treatment of cancer. Further, inhibitors of Stat3 that also do not inhibit Stat1 are described as well as their derivatives. Methods of screening additional compounds for Stat3 inhibition activity and / or non-inhibition of Stat1 activity are also described herein.

Description

[0001]The present invention claims priority to U.S. Provisional Patent Application Ser. No. 61 / 058,742, filed Jun. 4, 2008, which is incorporated by reference herein in its entirety.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]This invention was made with government support under National Institutes of Health Grants R01 CA072261 and R01 CA86430. The United States Government has certain rights in the invention.TECHNICAL FIELD[0003]The present invention generally concerns at least the fields of computational biology, cell biology, molecular biology, cancer biology, and medicine.BACKGROUND OF THE INVENTION[0004]Signal transducer and activator of transcription 3 (Stat3) is an oncogene (Bromberg et al., 1999) and one of seven members of the STAT protein family, which are signaling intermediates that mediate the actions of many cytokines and growth factors. Stat3 is constitutively active in many different cancers including prostate, breast, lung, squamous cell carc...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): A61K31/192C12N5/09A61K31/357A61K31/352A61K31/427A61K31/195A61K31/513A61P35/00A61P31/12A61P1/00A61P11/06A61P17/06A61P25/00A61P1/18A61P27/02C12N5/071
CPCA61K31/19A61K31/275C07D311/74C07D405/06C07D417/06A61P1/00A61P1/18A61P11/00A61P11/06A61P17/06A61P25/00A61P27/02A61P31/12A61P35/00A61K31/192A61K31/194A61K31/357A61K31/37A61K31/427A61K31/515A61K45/06C07C65/17C07C311/21
Inventor TWEARDY, DAVID J.HUANG, WANZHIKASEMBELI, MOSES M.
Owner BAYLOR COLLEGE OF MEDICINE
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