Premature termination codons (PTCs) prevent translation of a full-length protein and trigger nonsense-mediated mRNA decay (NMD). Nonsense suppression (also termed readthrough) therapy restores ...protein function by selectively suppressing translation termination at PTCs. Poor efficacy of current readthrough agents prompted us to search for better compounds. An NMD-sensitive NanoLuc readthrough reporter was used to screen 771,345 compounds. Among the 180 compounds identified with readthrough activity, SRI-37240 and its more potent derivative SRI-41315, induce a prolonged pause at stop codons and suppress PTCs associated with cystic fibrosis in immortalized and primary human bronchial epithelial cells, restoring CFTR expression and function. SRI-41315 suppresses PTCs by reducing the abundance of the termination factor eRF1. SRI-41315 also potentiates aminoglycoside-mediated readthrough, leading to synergistic increases in CFTR activity. Combining readthrough agents that target distinct components of the translation machinery is a promising treatment strategy for diseases caused by PTCs.
A variety of commercial analogs and a newer series of Sulindac derivatives were screened for inhibition of M. tuberculosis (Mtb) in vitro and specifically as inhibitors of the essential mycobacterial ...tubulin homolog, FtsZ. Due to the ease of preparing diverse analogs and a favorable in vivo pharmacokinetic and toxicity profile of a representative analog, the Sulindac scaffold may be useful for further development against Mtb with respect to in vitro bacterial growth inhibition and selective activity for Mtb FtsZ versus mammalian tubulin. Further discovery efforts will require separating reported mammalian cell activity from both antibacterial activity and inhibition of Mtb FtsZ. Modeling studies suggest that these analogs bind in a specific region of the Mtb FtsZ polymer that differs from human tubulin and, in combination with a pharmacophore model presented herein, future hybrid analogs of the reported active molecules that more efficiently bind in this pocket may improve antibacterial activity while improving other drug characteristics.
The nonsteroidal anti-inflammatory drug (NSAID) sulindac demonstrates attractive anticancer activity, but the toxicity resulting from cyclooxygenase (COX) inhibition and the suppression of ...physiologically important prostaglandins precludes its long-term, high dose use in the clinic for cancer prevention or treatment. While inflammation is a known tumorigenic driver, evidence suggests that sulindac's antineoplastic activity is partially or fully independent of its COX inhibitory activity. One COX-independent target proposed for sulindac is cyclic guanosine monophosphate phosphodiesterase (cGMP PDE) isozymes. Sulindac metabolites, i.e., sulfide and sulfone, inhibit cGMP PDE enzymatic activity at concentrations comparable with those associated with cancer cell growth inhibitory activity. Additionally, the cGMP PDE isozymes PDE5 and PDE10 are overexpressed during the early stages of carcinogenesis and appear essential for cancer cell proliferation and survival based on gene silencing experiments. Here, we describe a novel amide derivative of sulindac, sulindac sulfide amide (SSA), which was rationally designed to eliminate COX-inhibitory activity while enhancing cGMP PDE inhibitory activity. SSA was 68-fold and 10-fold less potent than sulindac sulfide (SS) in inhibiting COX-1 and COX-2, respectively, but 10-fold more potent in inhibiting growth and inducing apoptosis in breast cancer cells. The pro-apoptotic activity of SSA was associated with inhibition of cGMP PDE activity, elevation of intracellular cGMP levels, and activation of cGMP-dependent protein kinase (PKG) signaling, as well as the inhibition of β-catenin/Tcf transcriptional activity. SSA displayed promising in vivo anticancer activity, resulting in a 57% reduction in the incidence and a 62% reduction in the multiplicity of tumors in the N-methyl-N-nitrosourea (MNU)-induced model of breast carcinogenesis. These findings provide strong evidence for cGMP/PKG signaling as a target for breast cancer prevention or treatment and the COX-independent anticancer properties of sulindac. Furthermore, this study validates the approach of optimizing off-target effects by reducing the COX-inhibitory activity of sulindac for future targeted drug discovery efforts to enhance both safety and efficacy.
As part of an ongoing program to study the anticancer activity of non-steroidal anti-inflammatory drugs (NSAIDs) through generating diversity libraries of multiple NSAID scaffolds, we synthesized a ...series of NSAID amide derivatives and screened these sets against three cancer cell lines (prostate, colon and breast) and Wnt/β-catenin signaling. The evaluated amide analog libraries show significant anticancer activity/cell proliferation inhibition, and specific members of the sets show inhibition of Wnt/β-catenin signaling.
Acute kidney injury (AKI) is a major public health concern with significant morbidity and mortality and no current treatments beyond supportive care and dialysis. Preclinical studies have suggested ...that heme-oxygenase-1 (HO-1), an enzyme that catalyzes the breakdown of heme, has promise as a potential therapeutic target for AKI. Clinical trials involving HO-1 products (biliverdin, carbon monoxide, and iron), however, have not progressed beyond the Phase ½ level. We identified small-molecule inducers of HO-1 that enable us to exploit the full therapeutic potential of HO-1, the combination of its products, and yet-undefined effects of the enzyme system. Through cell-based, high-throughput screens for induction of HO-1 driven by the human HO-1 promoter/enhancer, we identified two novel small molecules and broxaldine (an FDA-approved drug) for further consideration as candidate compounds exhibiting an Emax ≥70% of 5 µM hemin and EC50 <10 µM. RNA sequencing identified shared binding motifs to NRF2, a transcription factor known to regulate antioxidant genes, including HMOX1. In vitro, the cytoprotective function of the candidates was assessed against cisplatin-induced cytotoxicity and apoptosis. In vivo, delivery of a candidate compound induced HO-1 expression in the kidneys of mice. This study serves as the basis for further development of small-molecule HO-1 inducers as preventative or therapeutic interventions for a variety of pathologies, including AKI.
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Amyotrophic lateral sclerosis (ALS) is a rare and progressive neurodegenerative disease with unknown etiology. It is caused by the degeneration of motor neurons responsible for ...controlling voluntary muscles. It has been reported that mutations in the superoxide dismutase (SOD) 1 gene can lead to ALS. SOD1 abnormalities have been identified in both familial, as well as sporadic ALS cases. SOD2 is a highly inducible SOD that works in conjunction with SOD1. SOD2 can be induced through activation of NF-κBs. We previously reported that the novel small molecule, SRI-22818, increases NF-κB expression and activation and SOD2 levels in vitro and has activity in vivo in the SOD1-G93A reference model of ALS. We report herein the synthesis and biological evaluation of SRI-22818 analogs.
Nanofibrous biocomposite scaffolds of type I collagen and nanohydroxyapatite (nanoHA) of varying compositions (wt %) were prepared by electrostatic cospinning. The scaffolds were characterized for ...structure and morphology by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques. The scaffolds have a porous nanofibrous morphology with random fibers in the range of 500−700 nm diameters, depending on the composition. FT-IR and XRD showed the presence of nanoHA in the fibers. The surface roughness and diameter of the fibers increased with the presence of nanoHA in biocomposite fiber as evident from AFM images. Tensile testing and nanoindendation were used for the mechanical characterization. The pure collagen fibrous matrix (without nanoHA) showed a tensile strength of 1.68 ± 0.10 MPa and a modulus of 6.21 ± 0.8 MPa with a strain to failure value of 55 ± 10%. As the nanoHA content in the randomly oriented collagen nanofibers increased to 10%, the ultimate strength increased to 5 ± 0.5 MPa and the modulus increased to 230 ± 30 MPa. The increase in tensile modulus may be attributed to an increase in rigidity over the pure polymer when the hydroxyapatite is added and/or the resulting strong adhesion between the two materials. The vapor phase chemical crosslinking of collagens using glutaraldehyde further increased the mechanical properties as evident from nanoindentation results. A combination of nanofibrous collagen and nanohydroxyapatite that mimics the nanoscale features of the extra cellular matrix could be promising for application as scaffolds for hard tissue regeneration, especially in low or nonload bearing areas.
Summary High throughput phenotypic screening of large commercially available libraries through two NIH programs has produced thousands of potentially interesting hits for further development as ...antitubercular agents. Unfortunately, these screens do not supply target information, and further follow up target identification is required to allow optimal rational design and development of highly active and selective clinical candidates. Cheminformatic analysis of the quinoline and quinazoline hits from these HTS screens suggested a hypothesis that certain compounds in these two classes may target the mycobacterial tubulin homolog, FtsZ. In this brief communication, activity of a lead quinoline against the target FtsZ from Mycobacterium tuberculosis ( Mtb ) is confirmed as well as good in vitro whole cell antibacterial activity against Mtb H37 Rv. The identification of a putative target of this highly tractable pharmacophore should help medicinal chemists interested in targeting FtsZ and cell division develop a rational design program to optimize this activity toward a novel drug candidate.
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Arsenicals belong to the class of chemical warfare agents known as vesicants, which are highly reactive, toxic and cause robust inflammatory response. Cutaneous exposure to arsenicals ...causes a wide range of systemic organ damage, beginning with cutaneous injuries, and later manifest multi-organ damage and death. Thus, the development of suitable antidotes that can effectively block injury following exposure to these agents is of great importance. Bromodomain 4 (BRD4), a member of the bromodomain and extra terminal domain (BET) family, plays crucial role in regulating transcription of inflammatory, proliferation and cell cycle genes. In this context, the development of potent small molecule inhibitors of BRD4 could serve as potential antidotes for arsenicals. Herein, we describe the synthesis and biological evaluation of a series of compounds.
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