The secreted Wnt signaling molecules are essential to the coordination of cell-fate decision making in multicellular organisms. In adult animals, the secreted Wnt proteins are critical for tissue ...regeneration and frequently contribute to cancer. Small molecules that disable the Wnt acyltransferase Porcupine (Porcn) are candidate anticancer agents in clinical testing. Here we have systematically assessed the effects of the Porcn inhibitor (WNT-974) on the regeneration of several tissue types to identify potentially unwanted chemical effects that could limit the therapeutic utility of such agents. An unanticipated observation from these studies is proregenerative responses in heart muscle induced by systemic chemical suppression of Wnt signaling. Using in vitro cultures of several cell types found in the heart, we delineate the Wnt signaling apparatus supporting an antiregenerative transcriptional program that includes a subunit of the nonfibrillar collagen VI. Similar to observations seen in animals exposed to WNT-974, deletion of the collagen VI subunit, COL6A1, has been shown to decrease aberrant remodeling and fibrosis in infarcted heart tissue. We demonstrate that WNT-974 can improve the recovery of heart function after left anterior descending coronary artery ligation by mitigating adverse remodeling of infarcted tissue. Injured heart tissue exposed to WNT-974 exhibits decreased scarring and reduced Col6 production. Our findings support the development of Porcn inhibitors as antifibrotic agents that could be exploited to promote heart repair following injury.
Thermosensitive liposomal doxorubicin (LTSL-Dox) combined with mild hyperthermia enhances the localized delivery of doxorubicin (Dox) within a heated region. The optimal heating duration and the ...impact of extended heating on systemic drug distribution are unknown. Here we evaluated local and systemic Dox delivery with two different mild hyperthermia durations (42 °C for 10 or 40 minutes) in a Vx2 rabbit tumor model. We hypothesized that longer duration of hyperthermia would increase Dox concentration in heated tumors without increasing systemic exposure. Temporally and spatially accurate controlled hyperthermia was achieved using a clinical MR-HIFU system for the prescribed heating durations. Forty-minutes of heating resulted in a nearly 6-fold increase in doxorubicin concentration in heated vs unheated tumors in the same animals. Therapeutic ratio, defined as the ratio of Dox delivered into the heated tumor vs the heart, increased from 1.9-fold with 10 minutes heating to 4.4-fold with 40 minutes heating. MR-HIFU can be used to guide, deliver and monitor mild hyperthermia of a Vx2 tumor model in a rabbit model, and an increased duration of heating leads to higher Dox deposition from LTSL-Dox in a target tumor without a concomitant increase in systemic exposure. Results from this preclinical study can be used to help establish clinical treatment protocols for hyperthermia mediated drug delivery.
Mutations in the adenomatous polyposis coli (APC) gene are common in colorectal cancer (CRC), and more than 90% of those mutations generate stable truncated gene products. We describe a chemical ...screen using normal human colonic epithelial cells (HCECs) and a series of oncogenically progressed HCECs containing a truncated APC protein. With this screen, we identified a small molecule, TASIN-1 (truncated APC selective inhibitor-1), that specifically kills cells with APC truncations but spares normal and cancer cells with wild-type APC. TASIN-1 exerts its cytotoxic effects through inhibition of cholesterol biosynthesis. In vivo administration of TASIN-1 inhibits tumor growth of CRC cells with truncated APC but not APC wild-type CRC cells in xenograft models and in a genetically engineered CRC mouse model with minimal toxicity. TASIN-1 represents a potential therapeutic strategy for prevention and intervention in CRC with mutant APC.
Lung cancer is one of the most lethal forms of cancer and current chemotherapeutic strategies lack broad specificity and efficacy. Recently, β-lapachone (β-lap) was shown to be highly efficacious in ...killing non-small cell lung cancer (NSCLC) cells regardless of their p53, cell cycle and caspase status. Pre-clinical and clinical use of β-lap (clinical form, ARQ501 or 761) is hampered by poor pharmacokinetics and toxicity due to hemolytic anemia. Here, we report the development and preclinical evaluation of β-lap prodrug nanotherapeutics consisting of diester derivatives of β-lap encapsulated in biocompatible and biodegradable poly(ethylene glycol)-b-poly(d,l-lactic acid) (PEG-b-PLA) micelles. Compared to the parent drug, diester derivatives of β-lap showed higher drug loading densities inside PEG-b-PLA micelles. After esterase treatment, micelle-delivered β-lap-dC3 and -dC6 prodrugs were converted to β-lap. Cytotoxicity assays using A549 and H596 lung cancer cells showed that both micelle formulations maintained NAD(P)H:quinone oxidoreductase 1 (NQO1)-dependent cytotoxicity. However, antitumor efficacy study of β-lap-dC3 micelles against orthotopic A549 NSCLC xenograft-bearing mice showed significantly greater long-term survival over β-lap-dC6 micelles or β-lap-HPβCD complexes. Improved therapeutic efficacy of β-lap-dC3 micelles correlated with higher area under the concentration-time curves of β-lap in tumors, and enhanced pharmacodynamic endpoints (e.g., PARP1 hyperactivation, γH2AX, and ATP depletion). β-Lap-dC3 prodrug micelles provide a promising strategy for NQO1-targeted therapy of lung cancer with improved safety and antitumor efficacy.
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Traumatic brain injury (TBI) is the largest non-genetic, non-aging related risk factor for Alzheimer’s disease (AD). We report here that TBI induces tau acetylation (ac-tau) at sites acetylated also ...in human AD brain. This is mediated by S-nitrosylated-GAPDH, which simultaneously inactivates Sirtuin1 deacetylase and activates p300/CBP acetyltransferase, increasing neuronal ac-tau. Subsequent tau mislocalization causes neurodegeneration and neurobehavioral impairment, and ac-tau accumulates in the blood. Blocking GAPDH S-nitrosylation, inhibiting p300/CBP, or stimulating Sirtuin1 all protect mice from neurodegeneration, neurobehavioral impairment, and blood and brain accumulation of ac-tau after TBI. Ac-tau is thus a therapeutic target and potential blood biomarker of TBI that may represent pathologic convergence between TBI and AD. Increased ac-tau in human AD brain is further augmented in AD patients with history of TBI, and patients receiving the p300/CBP inhibitors salsalate or diflunisal exhibit decreased incidence of AD and clinically diagnosed TBI.
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•Brain injury induces Alzheimer’s disease-like neuronal ac-tau•Neurodegenerative brain injury is reflected by ac-tau blood levels in mice and people•Decreasing ac-tau after brain injury at multiple signaling nodes is neuroprotective•Ac-tau-inhibiting medicines are associated with reduced neurodegenerative disease
Reducing brain injury-induced neuronal tau acetylation is neuroprotective in traumatic brain injury and has a role in Alzheimer’s disease pathogenesis.
Endothelial migration is a crucial aspect of a variety of physiologic and pathologic conditions including atherosclerosis and vascular repair. Reactive oxygen species (ROS) function as second ...messengers during endothelial migration. Multiple intracellular sources of ROS are regulated by cellular context, external stimulus, and the microenvironment. However, the predominant source of ROS during endothelial cell (EC) migration and the mechanisms by which ROS regulate cell migration are incompletely understood. In this study, we tested the hypothesis that mitochondria-derived ROS (mtROS) regulate EC migration. In cultured human umbilical vein endothelial cells, VEGF increased mitochondrial metabolism, promoted mtROS production, and induced cell migration. Either the targeted mitochondrial delivery of the antioxidant, vitamin E (Mito-Vit-E), or the depletion of mitochondrial DNA abrogated VEGF-mediated mtROS production. Overexpression of mitochondrial catalase also inhibited VEGF-induced mitochondrial metabolism, Rac activation, and cell migration. Furthermore, these interventions suppressed VEGF-stimulated EC migration and blocked Rac1 activation in endothelial cells. Constitutively active Rac1 reversed Mito-Vit-E-induced inhibition of EC migration. Mito-Vit-E also attenuated carotid artery reendothelialization in vivo. These results provide strong evidence that mtROS regulate EC migration through Rac-1.
We previously reported the discovery of P7C3, an aminopropyl carbazole having proneurogenic and neuroprotective properties in newborn neural precursor cells of the dentate gyrus. Here, we provide ...evidence that P7C3 also protects mature neurons in brain regions outside of the hippocampus. P7C3 blocks 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-mediated cell death of dopaminergic neurons in the substantia nigra of adult mice, a model of Parkinson disease (PD). Dose–response studies show that the P7C3 analog P7C3A20 blocks cell death with even greater potency and efficacy, which parallels the relative potency and efficacy of these agents in blocking apoptosis of newborn neural precursor cells of the dentate gyrus. P7C3 and P7C3A20 display similar relative effects in blocking 1-methyl-4-phenylpyridinium (MPP ⁺)-mediated death of dopaminergic neurons in Caenorhabditis elegans , as well as in preserving C. elegans mobility following MPP ⁺ exposure. Dimebon, an antihistaminergic drug that is weakly proneurogenic and neuroprotective in the dentate gyrus, confers no protection in either the mouse or the worm models of PD. We further demonstrate that the hippocampal proneurogenic efficacy of eight additional analogs of P7C3 correlates with their protective efficacy in MPTP-mediated neurotoxicity. In vivo screening of P7C3 analogs for proneurogenic efficacy in the hippocampus may thus provide a reliable means of predicting neuroprotective efficacy. We propose that the chemical scaffold represented by P7C3 and P7C3A20 provides a basis for optimizing and advancing pharmacologic agents for the treatment of patients with PD.
Pyruvate dehydrogenase kinase isoforms (PDKs 1–4) negatively regulate activity of the mitochondrial pyruvate dehydrogenase complex by reversible phosphorylation. PDK isoforms are up-regulated in ...obesity, diabetes, heart failure, and cancer and are potential therapeutic targets for these important human diseases. Here, we employed a structure-guided design to convert a known Hsp90 inhibitor to a series of highly specific PDK inhibitors, based on structural conservation in the ATP-binding pocket. The key step involved the substitution of a carbonyl group in the parent compound with a sulfonyl in the PDK inhibitors. The final compound of this series, 2-(2,4-dihydroxyphenyl)sulfonylisoindoline-4,6-diol, designated PS10, inhibits all four PDK isoforms with IC50 = 0.8 μm for PDK2. The administration of PS10 (70 mg/kg) to diet-induced obese mice significantly augments pyruvate dehydrogenase complex activity with reduced phosphorylation in different tissues. Prolonged PS10 treatments result in improved glucose tolerance and notably lessened hepatic steatosis in the mouse model. The results support the pharmacological approach of targeting PDK to control both glucose and fat levels in obesity and type 2 diabetes.
Up-regulated pyruvate dehydrogenase kinase isoforms (PDKs) are associated with impaired glucose homeostasis in diabetes.
Novel PDK inhibitors were developed using structure-based design, which improves glucose tolerance with reduced hepatic steatosis in diet-induced obese mice.
Obesity phenotypes are effectively treated by chemical intervention with PDK inhibitors.
PDKs are potential drug targets for obesity and type 2 diabetes.
The enzyme 15-prostaglandin dehydrogenase (15-PGDH) catalyzes the first step in the degradation of prostaglandins including PGE2. It is a negative regulator of tissue repair and regeneration in ...multiple organs. Accordingly, inhibitors of 15-PGDH are anticipated to elevate in vivo levels of PGE2 and to promote healing and tissue regeneration. The small molecule SW033291 (1) inhibits 15-PGDH with K
= 0.1 nM in vitro, doubles PGE2 levels in vivo, and shows efficacy in mouse models of recovery from bone marrow transplantation, ulcerative colitis, and partial hepatectomy. Here we describe optimized variants of 1 with improved solubility, druglike properties, and in vivo activity.
We previously reported the discovery of P7C3, an aminopropyl carbazole having proneurogenic and neuroprotective properties in newborn neural precursor cells of the hippocampal dentate gyrus. We have ...further found that chemicals having efficacy in this in vivo screening assay also protect dopaminergic neurons of the substantia nigra following exposure to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, a mouse model of Parkinson disease. Here, we provide evidence that an active analog of P7C3, known as P7C3A20, protects ventral horn spinal cord motor neurons from cell death in the G93A-SOD1 mutant mouse model of amyotrophic lateral sclerosis (ALS). P7C3A20 is efficacious in this model when administered at disease onset, and protection from cell death correlates with preservation of motor function in assays of walking gait and in the accelerating rotarod test. The prototypical member of this series, P7C3, delays disease progression in G93A-SOD1 mice when administration is initiated substantially earlier than the expected time of symptom onset. Dimebon, an antihistaminergic drug with significantly weaker proneurogenic and neuroprotective efficacy than P7C3, confers no protection in this ALS model. We propose that the chemical scaffold represented by P7C3 and P7C3A20 may provide a basis for the discovery and optimization of pharmacologic agents for the treatment of ALS.
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