Journal of Pharmacology and Experimental Therapeutics最新文献

The heterogeneity and treatment resistance of glioblastoma (GBM) can be addressed through multidrug combination therapies that target multiple biological pathways simultaneously. In this study, we explored the repurposing of antiepileptic drugs with potential antitumor effects, combined with the Janus kinase/signal transducer and activator of transcription-3 (JAK/STAT3) inhibitor ruxolitinib (RUX), as an alternative local therapeutic approach for GBM. The cytotoxic effects of valproic acid (VPA), oxcarbazepine (OXC), and gabapentin (GBP) were evaluated on A172 and U251 GBM cells. Both VPA and OXC significantly reduced cell viability, prompting further investigation of their effects in combination with RUX. When tested in 3-dimensional multicellular tumorspheres, the combinations at their IC50 exhibited suboptimal effectiveness compared with single-agent treatment. Using a factorial experimental design based on a minimal combination approach to analyze dose-response data, followed by subsequent Bliss synergy analysis, synergistic interactions were revealed exclusively for RUX + VPA on A172 cells. Although the interaction between RUX and OXC was additive, GBM cells displayed increased sensitivity to this combination, suggesting potential therapeutic value. Ultimately, the most effective drug ratios were assessed using live/dead cell fluorescence staining in 3-dimensional multicellular tumorspheres. The variable treatment response observed among GBM cell lines underscores the need for personalized treatment strategies tailored to the specific molecular profile of individual tumors. SIGNIFICANCE STATEMENT: Given the unmet needs in glioblastoma treatment, the study explores novel combinations of Janus kinase/signal transducer and activator of transcription-3 inhibitor ruxolitinib and antiepileptics for local codelivery, aiming to overcome resistance and heterogeneity through synergistic effects and sustained release via molecularly imprinted reservoirs.

The mechanisms underlying L-DOPA-induced dyskinesia (LID) largely arise from maladaptive plasticity in striatal circuits leading to altered neuronal responses to dopamine (DA) signaling. Cyclic nucleotides play a major role in the molecular cascades of DA signaling, and particularly cAMP is known to be associated with LID mechanisms. Cyclic nucleotide levels in striatal neurons are regulated by phosphodiesterases (PDEs), and 1 isoenzyme with selective affinity for cAMP and high expression in the striatum is PDE7. Here, the PDE7 inhibitor OMS-401 was evaluated for antidyskinetic effects in a nonhuman primate (NHP) model of advanced Parkinson's disease. A series of systemic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine administration followed by chronic L-DOPA treatment were used to induce advanced parkinsonism and reproducible LID in a group of 3 macaques. The effects of the PDE7 inhibitor OMS-401 were analyzed with a dose-response curve design in coadministration trials for 2 doses of L-DOPA (optimal and suboptimal). Motor disability, LID, and drug adverse reactions were assessed using standardized scales for 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated NHPs. OMS-401 significantly reduced LIDs in a dose-dependent fashion without interacting with the antiparkinsonian action of L-DOPA or inducing side effects in parkinsonian NHPs. Results confirm that cAMP levels in striatal neurons play a critical role in LID mechanisms, and that PDE7 inhibition may be a strategy to control LID over the long-term DA replacement therapy in Parkinson's disease. SIGNIFICANCE STATEMENT: This study shows that selective phosphodiesterase 7 inhibition with OMS-401 reduces dyskinesia in a Parkinson's primate model without affecting L-DOPA's benefits. Phosphodiesterase 7 inhibition may offer a promising approach for L-DOPA-induced dyskinesia management, providing an alternative to treatments with dose-limiting side effects.

Despite advances in therapies that target low-density lipoprotein (LDL), atherosclerotic cardiovascular disease (ASCVD) remains a major cause of morbidity and mortality. This has led to the investigation of other biomarkers, including lipoprotein(a) [Lp(a)]. Lp(a) is a variant of LDL that is genetically determined, has proatherogenic, proinflammatory, and prothrombotic effects, and has a linear correlation with ASCVD risk. Approximately 20%-30% of the global population has elevated serum Lp(a). Recommendations for increased Lp(a) testing has heightened the need for effective medications to target this biomarker. Although traditional antilipemic agents have demonstrated negligible effects on Lp(a), multiple targeted therapies are emerging, including antisense oligonucleotides, small interfering RNA agents, and small molecules. The efficacy of these novel agents observed in early clinical trials and the development of alternate treatment modalities, including gene editing and RNA-based innovations, signal a promising new era of ASCVD prevention via non-LDL pathways. SIGNIFICANCE STATEMENT: Lipoprotein(a) is a genetically determined biomarker that significantly impacts atherosclerotic risk. The development of novel therapies that lower lipoprotein(a) warrants a broad understanding to increase comfortability and optimize utilization upon market approval.

Targeted protein degradation is an emerging strategy for experimental and therapeutic ablation of biologically important proteins. To elicit the degradation of their cellular targets, targeted protein degraders act by co-opting the endogenous cellular degradation machineries through chemically-induced proximity. While targeted protein degradation was serendipitously discovered as the mode of action of approved anticancer drugs including fulvestrant and thalidomide, recent years have witnessed systematic endeavors for the rational design of targeted protein degraders for diverse biological targets. Such endeavors have led to 3 major classes of targeted protein degraders including molecular glue degraders, proteolysis targeting chimeras, and hydrophobic tag-based degraders. Of these, several agents are clinically approved or currently evaluated in clinical trials for use in diseases such as cancer, neurodegenerative disorders, autoimmune and dermatologic conditions. The novel chemical and pharmacologic nature of targeted protein degraders heralds an emerging paradigm of pharmacology, known as event-driven pharmacology, which is different in many aspects from the occupancy-based pharmacology of conventional small-molecule inhibitors. In this review, we discuss the emerging pharmacology of different classes of targeted protein degraders including the molecular basis of their drug action and key pharmacologic properties pertinent to efficacy, selectivity, safety, and dosing considerations. SIGNIFICANCE STATEMENT: Targeted protein degradation is a novel strategy that establishes induced-proximity pharmacology as a promising next-generation therapeutic modality. This review provides insights into the common organizing principles of this emerging approach and the prospects for this rapidly evolving field.

Proteolysis-targeting chimeras (PROTACs) are gathering considerable interest due to their ability to address previously undruggable targets. We were keen to understand the potential for these very large molecules to interact with transporters that may influence absorption, distribution, metabolism, and excretion or toxicity properties and to what extent this may be predictable using machine learning models. Consequently, we tested a set of PROTACs against several human drug transporters, namely the equilibrative nucleoside (ENT) family transporters ENT1 and ENT2, which have been directly implicated in the uptake of anticancer or antiviral drugs into target cells. We describe the dramatic inhibition observed for ENT1 and ENT2 but not for the unrelated transporter organic anion transporter 4. In addition, we report dose-response relationships for ENT1 to show some PROTACs are nanomolar inhibitors. We also explored the chemistry space of small molecules tested against ENT1 and ENT2 and compared them with PROTACs to illustrate that they are found on the periphery and close to other larger small molecules. While PROTACs are thought of as a dissimilar class to small molecules, it may be possible to bring them closer to those Food and Drug Administration-approved orally available large molecules, and in turn, increase their oral bioavailability. The outcomes of these combined in vitro and computational assessments could influence PROTAC development, be useful for their repurposing as ENT1 inhibitors for several disease indications beyond their primary one, and be used for transporter machine learning model generation and evaluation. SIGNIFICANCE STATEMENT: Proteolysis-targeting chimeras are an increasingly popular class of molecules for which we do not have a complete picture of their absorption, distribution, metabolism, and excretion or toxicity properties. For example, their interactions with uptake and efflux transporters are unknown. Here, we provide evidence that many proteolysis-targeting chimeras act as inhibitors of equilibrative nucleoside transporters 1 and 2. We hope to stimulate further study of their potential for inhibition of other transporters.

The opioid antagonists, naloxone and nalmefene, are used clinically to rapidly reverse opioid overdose, but often precipitate withdrawal symptoms in opioid-dependent individuals. This study compared 2 medications used for opioid use disorder, buprenorphine and methadone, to naloxone for reversing fentanyl-induced effects in rats. Buprenorphine alone did not produce significant respiratory depression at 0.5-5.0 mg/kg. Rats were challenged with 0.1 mg/kg fentanyl, which resulted in a significant reduction in oxygen saturation (SpO₂), and naloxone 0.1 mg/kg, buprenorphine 3.0 mg/kg, methadone 2.25 mg/kg, or saline control was given to reverse fentanyl effects. Antinociception and SpO₂ were restored to baseline by 15 minutes after administration of naloxone and buprenorphine. The saline group showed a slow return to baseline SpO₂ within 30 minutes, whereas methadone extended the duration of, but did not enhance, the effects of fentanyl. To determine whether buprenorphine could rapidly (within minutes) reverse fentanyl-induced respiratory depression, rats were given a dose of fentanyl 0.1 mg/kg s.c., followed by saline, naloxone 0.1 mg/kg, or buprenorphine 3.0 mg/kg, and SpO₂ was monitored continuously for 10 minutes. Both naloxone and buprenorphine reversed fentanyl effects within 3.5 minutes, whereas the saline group did not return to baseline levels during the monitoring period. Buprenorphine at 0.3 and 1.0 mg/kg also reversed fentanyl effects, with a slower onset of reversal. In a follow-up study, rats received fentanyl followed by saline, buprenorphine, or methadone for reversal, and blood and brain levels were measured. Fentanyl concentration in the brain was not significantly affected by methadone and buprenorphine treatment, suggesting that differences in SpO₂ were not attributable to pharmacokinetic interactions. These data support repurposing buprenorphine for the treatment of opioid overdose. SIGNIFICANCE STATEMENT: Opioid overdoses cause ∼80,000 annual deaths in the United States. Buprenorphine is an opioid partial agonist used for opioid use disorder. This study used a rat model to compare buprenorphine to naloxone for efficacy in reversing fentanyl-induced respiratory depression.

Cocaine-associated stimuli acquire conditioned reinforcing effects and can precipitate relapse. We used the New Response Acquisition procedure to examine factors that influenced the conditioned reinforcing effects of cocaine-associated stimuli in rats. According to this procedure, rats first experienced Pavlovian conditioning, during which they were exposed to intravenous cocaine deliveries and stimulus (light + white noise) presentations. After Pavlovian conditioning, animals learned to respond to the cocaine-paired stimulus alone. The number of responses made for that stimulus reflected the conditioned reinforcing effects of the cocaine-associated stimulus. Across 3 experiments, the extent to which the dose of cocaine during Pavlovian conditioning (experiment 1), food restriction (experiment 2), and the number of cocaine-stimulus pairings and the number of days of Pavlovian conditioning (experiment 3) led to different conditioned reinforcing effects of the cocaine-associated stimulus. Taken together, we found that cocaine-associated cues took on conditioned reinforcing effects dose-dependently, were augmented by food restriction, and were most robust following 10 days of Pavlovian conditioning relative to 5 days of conditioning. These findings advance our understanding of the conditions under which cocaine-associated stimuli can act as a conditioned reinforcer. SIGNIFICANCE STATEMENT: Cocaine-associated stimuli acquire conditioned reinforcing effects via Pavlovian conditioning that drive drug-seeking and relapse. Understanding the conditions under which cocaine-associated stimuli take on conditioned reinforcing effects can be used to inform efforts to curtail cocaine use disorder.

γ-aminobutyric acid type-A receptors associate with auxiliary proteins such as Shisa7 and have allosteric binding sites for benzodiazepines, barbiturates, and alcohols. In this study, Shisa7 was knocked down to assess its involvement in the discriminative-stimulus effects of drugs from each class and in the positive reinforcing effects of alcohol. Twelve male Long-Evans rats were trained to respond in a drug-discrimination procedure with 6 trained to discriminate ethanol (1 g/kg) from saline and 6 trained to discriminate alprazolam (1.8 mg/kg) from cyclodextrin. Following training, cumulative dose-effect curves for ethanol, alprazolam, and pentobarbital were established before and after Shisa7 knockdown was achieved using an intravenous dicer substrate small-interfering ribonucleic acid. A separate group of 6 rats was also trained to consume ethanol orally to assess ethanol intake before and after Shisa7 knockdown. In general, before Shisa7 knockdown, alprazolam and pentobarbital partially substituted for ethanol in ethanol-trained subjects up to doses that decreased response rate, whereas pentobarbital, but not ethanol, partially substituted for alprazolam in alprazolam-trained subjects. After Shisa7 knockdown, the dose-effect curve for ethanol-lever responding in ethanol-trained subjects was shifted downward, the curve for alprazolam-lever responding in alprazolam-trained subjects was shifted rightward, and the curve for pentobarbital was shifted rightward in both ethanol- and alprazolam-trained subjects. Shisa7 knockdown did not affect response rates. In rats orally consuming ethanol, both ethanol intake and dose were significantly decreased after Shisa7 knockdown compared with the dicer substrate small-interfering ribonucleic acid control. These findings demonstrate that reducing Shisa7 levels attenuated the discriminative-stimulus effects of 3 positive allosteric modulators of γ-aminobutyric acid type-A receptors and decreased ethanol's reinforcing effects. SIGNIFICANCE STATEMENT: This study demonstrates that Shisa7, an auxiliary protein associated with γ-aminobutyric acid type-A receptor, plays a crucial role in mediating the discriminative-stimulus effects of ethanol, alprazolam, and pentobarbital, as well as the reinforcing effects of ethanol. By demonstrating that Shisa7 knockdown attenuates the behavioral effects of these drugs, the findings provide new insights into the molecular mechanisms underlying γ-aminobutyric acid type-A receptor-mediated drug effects and potentially identify Shisa7 as a key modulatory mechanism through which these drugs produce their effects.

Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder characterized by hyperandrogenism and frequently associated with insulin resistance (IR), a key pathogenic factor in PCOS. However, insulin sensitizers commonly used to treat PCOS are often recommended off-label and may cause side effects. This study investigated the therapeutic effects of pancreastatin inhibitor 8 (PSTi8), an insulin sensitizer, in a PCOS rat model. The PCOS rat model was established by daily feeding with a high-fat diet and administering subcutaneous injections of dehydroepiandrosterone at a dose of 60 mg/kg body weight for 21 days and further, followed by 21 days of treatment with PSTi8 (10 mg/kg) and metformin (300 mg/kg). Body weight, estrous cycle, glucose, and insulin tolerance test results were monitored. Ovarian morphology, estrous cycle changes, oxidative stress and inflammatory markers, steroidogenic hormone levels and protein expression, and insulin signaling pathway were assessed to evaluate the therapeutic effectiveness of PSTi8 in PCOS rats. This study found that PSTi8 improved IR and reduced body weight in PCOS rats. PSTi8 lowered serum levels of insulin (27%), testosterone (56%), estradiol (2-fold), progesterone (21%), sex hormone-binding globulin (7.5%), and luteinizing hormone/follicle stimulating hormone ratio (57%). Additionally, PSTi8 helped to restore ovarian morphology, estrous cycle, and improve dyslipidemia. PSTi8 treatment also reduces the oxidative stress level of total superoxide ismutase (16%), glutathione peroxidase (26%), and inflammation in PCOS rats. Furthermore, PSTi8 restores the steroidogenic protein expression and increases PI3K/Akt phosphorylation in PCOS rats. These findings demonstrate PSTi8 exhibited comparable efficacy to metformin in ameliorating IR and ovarian dysfunction in the studied PCOS model. SIGNIFICANCE STATEMENT: Polycystic ovary syndrome (PCOS) increases risk of reproductive and metabolic disorders, partly due to systemic inflammation. This study combined dehydroepiandrosterone with high-fat diet and successfully induced PCOS-like features in rats. PSTi8, a pancreastatin inhibitor known for insulin-sensitizing effects in various disease models, effectively reversed PCOS-associated pathophysiology. PSTi8 improves insulin sensitivity by activating the PI3K/AKT signaling pathway and ameliorates oxidative stress and inflammation in PCOS rats. Additionally, PSTi8 treatment normalized steroidogenesis protein expression and reduced circulating biomarkers linked to cardiovascular risk.

Exosomes are a category of extracellular vesicles with a 30-150 nm diameter that serve as carriers of distinct and functional biomolecules, such as lipids, nucleic acids, and proteins. They are released by almost all types of cells and mirror the characteristics of their originating cells, making them appealing for use in cell-free therapeutic applications. The skin is the largest organ of the body. It protects the entire body from the harsh environment, helps to maintain body temperature, supports life for all other body parts, plays a significant role in regulating the immune system, etc. Interventions in dermatology and cosmetology help to maintain good-looking and healthy skin. Exosomes have assumed a prominent position in cosmetics and dermatology by facilitating cellular regeneration. Recent studies have highlighted the efficacy of exosomes as effective antioxidants in therapy approaches such as hair regeneration, skin aging reversal, scar prevention, wound healing, dermatological diseases. This article explores the therapeutic applications and clinical interventions of exosomes in cosmetology and dermatology. It also discusses the challenges and prospects in the field. SIGNIFICANCE STATEMENT: Cell-free therapy using exosomes is an emerging area in disease management. Exosomes, nanosized extracellular vesicles, play a prominent role in various conditions such as hair growth and regeneration, reversal of aging, wound healing, and management of many skin-associated diseases, such as psoriasis, dermatitis, etc. This review describes the recent developments in the utilization of exosomes in dermatological and cosmetological treatment aspects, their regulatory issues, and current status of clinical trials.