Kv7 channel opener retigabine reduces self-administration of cocaine but not sucrose in rats.

The increasing rates of drug misuse highlight the urgency of identifying improved therapeutics for treatment. Most drug-seeking behaviours that can be modelled in rodents utilize the repeated intravenous self-administration (SA) of drugs. Recent studies examining the mesolimbic pathway suggest that Kv7/KCNQ channels may contribute to the transition from recreational to chronic drug use. However, to date, all such studies used noncontingent, experimenter-delivered drug model systems, and the extent to which this effect generalizes to rats trained to self-administer drugs is not known. Here, we tested the ability of retigabine (ezogabine), a Kv7 channel opener, to regulate instrumental behaviour in male Sprague Dawley rats. We first validated the ability of retigabine to target experimenter-delivered cocaine in a conditioned place preference (CPP) assay and found that retigabine reduced the acquisition of place preference. Next, we trained rats for cocaine-SA under a fixed-ratio or progressive-ratio reinforcement schedule and found that retigabine pretreatment attenuated the SA of low to moderate doses of cocaine. This was not observed in parallel experiments, with rats self-administering sucrose, a natural reward. Compared with sucrose-SA, cocaine-SA was associated with reductions in the expression of the Kv7.5 subunit in the nucleus accumbens, without alterations in Kv7.2 and Kv7.3. Therefore, these studies reveal a reward-specific reduction in SA behaviour and support the notion that Kv7 is a potential therapeutic target for human psychiatric diseases with dysfunctional reward circuitry.

The protective effects of Ferrostatin-1 against inflammation-induced preterm birth and fetal brain injury.

INTRODUCTION: Recent studies have suggested the involvement of ferroptosis in preterm birth. Despite compelling evidence, the underlying mechanism remains unknown. This investigation aimed to determine the therapeutic effects of Ferrostatin-1 (Fer-1), an inhibitor of ferroptosis, in preterm birth and fetal brain injury. METHODS: Human placenta samples and clinical data of participants were collected to ascertain whether placental ferroptosis was associated with preterm birth. Lipopolysaccharide (LPS)-induced preterm birth mouse model was used to examine the protective effects of Fer-1 on preterm birth. Fetal brain tissues and offspring mice at 5 and 8 weeks were studied to determine the effects of Fer-1 on the cognitive function of offspring. RESULTS: We examined the mechanism of spontaneous preterm birth and discovered that placental ferroptosis was associated with preterm birth. Fer-1 inhibited preterm birth by ameliorating placental ferroptosis and maternal inflammation, thus improving LPS-induced intrauterine inflammation to maintain pregnancy. Antenatal administration of Fer-1 prevented LPS-induced fetal brain damage in the acute phase and improved long-term neurodevelopmental impairments by improving placental neuroendocrine signaling and maintaining placental function. CONCLUSION: Fer-1 inhibited preterm birth and fetal brain injury by inhibiting maternal inflammation and improving placental function. Our findings provide a novel therapeutic strategy for preterm birth.

Therapeutic effect of N, N-Diphenyl-1,4-phenylenediamine and adipose-derived stem cells coadministration on diabetic cardiomyopathy in type 1 diabetes mellitus-rat model.

Type 1 diabetes stem-cell-based treatment approach is among the leading therapeutic strategies for treating cardiac damage owing to the stem cells' regeneration capabilities. Mesenchymal stem cells derived from adipose tissue (AD-MSCs) have shown great potential in treating diabetic cardiomyopathy (DCM). Herein, we explored the antioxidant-supporting role of N, N'-diphenyl-1,4-phenylenediamine (DPPD) in enhancing the MSCs' therapeutic role in alleviating DCM complications in heart tissues of type 1 diabetic rats. Six male albinos Wistar rat groups have been designed into the control group, DPPD (250 mg/kg, i.p.) group, diabetic-untreated group, and three diabetic rat groups treated with either AD-MSCs (1 × 106 cell/rat, i.v.) or DPPD or both. Interestingly, all three treated diabetic groups exhibited a significant decrease in serum glucose, HbA1c, heart dysfunction markers (lactate dehydrogenase and CK-MP) levels, and lipid profile fractions (except for HDL-C), as well as some cardiac oxidative stress (OS) levels (MDA, AGEs, XO, and ROS). On the contrary, serum insulin, C-peptide, and various cardiac antioxidant levels (GSH, GST, CAT, SOD, TAC, and HO-1), beside viable cardiac cells (G0/G1%), were markedly elevated compared with the diabetic untreated group. In support of these findings, the histological assay reflected a marked enhancement in the cardiac tissues of all diabetic-treated groups, with obvious excellency of the AD-MSCs + DPPD diabetic-treated group. Such results strongly suggested the great therapeutic potentiality of either DPPD or AD-MSCs single injection in enhancing the cardiac function of diabetic rats, with a great noted enhancement superiority of DPPD and AD-MSCs coadministration.

Oral exposure to tire rubber-derived contaminant 6PPD and 6PPD-quinone induce hepatotoxicity in mice.

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) is a widely used additive for protecting various rubber products, and its product of oxidation N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPDQ) has attracted extensive attention in aquatic toxicity. However, the toxicity of 6PPD and 6PPDQ in mammals has not been reported yet. In this study, the effects of 6PPD and 6PPDQ on the liver of C57BL/6 mice were assessed by orally administering different doses of 6PPD and 6PPDQ (10, 30, and 100 mg/kg) in mice for 6 weeks. 6PPD and 6PPDQ were found to bioaccumulate in the liver in a dose-dependent manner. Moreover, a high dose of 6PPD and 6PPDQ exposure increased not only the liver weights but also liver triglyceride levels, indicating that 6PPD and 6PPDQ exposure induced hepatotoxicity in mice. Furthermore, transcriptomic analysis revealed that 6PPD and 6PPDQ induced differential expression of genes mainly enriched in glycolipid metabolism, immune-related, and glutathione metabolism pathways. Therefore, 6PPD and 6PPDQ altered hepatic metabolism in mice. Furthermore, 6PPDQ could induce an immune response by upregulating the transcription of immune-related genes and promoting macrophage infiltration in the liver. In conclusion, our study revealed the toxic effects of 6PPD and 6PPDQ exposure on multi-endpoints in the liver of mice and improve our understanding of the health risks of 6PPD and 6PPDQ to mammals. The findings of our study may help formulate better safety regulations for the use and disposal of rubber products.

An injectable and biodegradable hydrogel incorporated with photoregulated NO generators to heal MRSA-infected wounds.

The development of degradable hydrogel fillers with high antibacterial activity and wound-healing property is urgently needed for the treatment of infected wounds. Herein, an injectable, degradable, photoactivated antibacterial hydrogel (MPDA-BNN6@Gel) was developed by incorporating BNN6-loaded mesoporous polydopamine nanoparticles (MPDA-BNN6 NPs) into a fibrin-based hydrogel. After administration, MPDA-BNN6@Gel created local hyperthermia and released large quantities of NO gas to treat methicillin-resistant Staphylococcus aureus infection under the stimulation of an 808 nm laser. Experiments confirmed that the bacteria were eradicated through irreversible damage to the cell membrane, genetic metabolism, and material energy. Furthermore, in the absence of laser irradition, the fibrin and small amount of NO that originated from MPDA-BNN6@Gel promoted wound healing in vivo. This work indicates that MPDA-BNN6@Gel is a promising alternative for the treatment of infected wounds and provides a facile tactic to design a photoregulated bactericidal hydrogel for accelerating infected wound healing. STATEMENT OF SIGNIFICANCE: The development of a degradable hydrogel with high antibacterial activity and wound-healing property is an urgent need for the treatment of infected wounds. Herein, an injectable, degradable, and photo-activated antibacterial hydrogel (MPDA-BNN6@Gel) has been developed by incorporating BNN6-loaded mesoporous polydopamine nanoparticles (MPDA-BNN6 NPs) into a fibrin-based hydrogel. After administration of MPDA-BNN6@Gel, the MPDA-BNN6@Gel could generate local hyperthermia and release large quantities of NO gas to treat the methicillin-resistant Staphylococcus aureus infection under the irradiation of 808 nm laser. Furthermore, in the absence of a laser, the fibrin and a small amount of NO originating from MPDA-BNN6@Gel could promote wound healing in vivo.

Ferrostatin-1 and 3-Methyladenine Ameliorate Ferroptosis in OVA-Induced Asthma Model and in IL-13-Challenged BEAS-2B Cells.

Ferroptosis was reported to be involved in the occurrence and development of asthma. However, the potential mechanism underlying the role of ferroptosis in asthma remains unclear. In this study, we established the mouse asthma model following the ovalbumin (OVA) method in C57BL/6 mice and the cell model with IL-13 induction in bronchial epithelial cells (BEAS-2B cells). Treatment of ferrostatin-1 (Ferr-1) and 3-methyladenine (3-MA) decreased iron deposition in IL-13-induced BEAS-2B cells and lung tissues of asthma mice, opposite to that in bronchoalveolar lavage fluid (BALF). Meanwhile, excessive lipid peroxidation asthma model in vivo and in vitro was alleviated by Ferr-1 or 3-MA treatment. In addition, Ferr-1 and 3-MA inhibited the expression of LC-3 in these cells and lung tissues of mice. Moreover, Ferr-1 and 3-MA also suppressed the production of inflammatory cytokines (IL-1ß, IL-6, and TNF-α) and oxidative stress factors (ROS and MDA), while promoting the level of SOD, in vivo and in vitro. Furthermore, application of Ferr-1 exhibited a greater inhibitory effect on iron release and lipid peroxidation in IL-13-induced BEAS-2B cells and asthma mice than 3-MA, accompanied with a weaker effect on ferritinophagy than 3-MA. Collectively, Ferr-1 and 3-MA ameliorated asthma in vivo and in vitro through inhibiting ferroptosis, providing a new strategy for the clinical treatment of asthma.

Epigenetic therapy combination of UNC0638 and CI-994 suppresses breast cancer via epigenetic remodeling of BIRC5 and GADD45A.

BACKGROUND: There is currently a growing interest in the roles of epigenetic mechanisms in the diagnosis, prognosis, and therapies associated with precision oncology for breast cancer (BC). This study aimed to demonstrate the clinical significance of euchromatic histone lysine methyltransferase 2 (EHMT2), histone deacetylase 1 (HDAC1) and HDAC2 in BC, to evaluate the antitumor effectiveness of a combination of the selective inhibitors UNC0638 and CI-994 (U+C), and to clarify the underlying mechanisms. METHODS: Multi-omic analysis was used to study the clinical significance of the biomarkers of interest. The effects of U+C treatment were evaluated by detecting cell viability, cell cycle, apoptosis, and representative gene expressions. RNA-Seq and Gene Set Enrichment Analysis (GSEA) were employed to identify over-represented genes associated with the treatment. Chromatin immunoprecipitation and qPCR (ChIP-qPCR) assay were applied to verify epigenetic profiling on the identified promoters. RESULTS: The significance of elevated expressions of EHMT2, HDAC1, and HDAC2 in tumor tissue and BC basal-like subtype in predicting a poor prognosis was noted. The U+C combined treatment showed an enhanced suppressive effect as compared to single agent treatment, perturbed the cell cycle, induced apoptosis, reduced expressions of the genes representing anti-apoptosis, stemness, drug resistance and basal-like state, while increasing luminal-like state genes. In addition, the combined U+C treatment suppressed xenograft tumor growth. The epigenetic reprogramming of histones was identified in the down-regulated BIRC5 and upregulated GADD45A. CONCLUSION: These findings demonstrate that selectively targeting EHMT2, HDAC1, and HDAC2 by concurrent U+C treatment suppresses BC tumor progression via epigenetic remodeling of BIRC5 and GADD45A.

RGFP966 is protective against lipopolysaccharide-induced depressive-like behaviors in mice by inhibiting neuroinflammation and microglial activation.

Depression is a prevalent mental disorder. However, its pathophysiological mechanism has still remained elusive, and a limited number of effective treatments have been presented. Recent studies have shown that neuroinflammation and microglial activation are involved in the pathogenesis of depression. Histone deacetylase 3 (HDAC3) has neurotoxic effects on several neuropathological conditions. The inhibition of HDAC3 has been reported to induce anti-inflammatory and antioxidant effects. RGFP966 is a highly selective inhibitor of HDAC3. This study aimed to investigate the antidepressant effect of RGFP966 on lipopolysaccharide (LPS)-induced depressive-like behaviors in mice and to explore its possible mechanism. Adult male C57BL/6J mice were utilized in this study. The LPS and RGFP966 were injected intraperitoneally daily for 5 days. The behavior tests were performed to elucidate the depression-like behaviors. Western blot, ELISA and immunofluorescence staining were used to study the HDAC3/TLR4/NLRP3 pathway-related proteins. The results of behavioral tests showed that RGFP966 could improve the LPS-induced depressive-like behaviors in mice. The results of Western blotting showed that RGFP966 treatment downregulated the expression levels of toll-like receptor 4 (TLR4), nucleotide-binding oligomerization domain-like receptor pyrin domain-containing-3 (NLRP3), caspase-1, and interleukin-1ß (IL-1ß) (P < 0.05). Furthermore, the results of immunofluorescence staining showed that RGFP966 treatment inhibited microglial activation in the hippocampus of mice (P < 0.01). These findings suggested that RGFP966 could effectively ameliorate LPS-induced depressive-like behaviors in mice by inhibiting neuroinflammation and microglial activation. The anti-inflammatory mechanism of RGFP966 might be related to the inhibition of the HDAC3/TLR4/NLRP3 signaling pathway. Therefore, inhibition of HDAC3 using RGFP966 could serve as a potential treatment strategy for depression.

Ferrostatin-1 protects auditory hair cells from cisplatin-induced ototoxicity in vitro and in vivo.

Cisplatin is used in a wide variety of malignancies, but cisplatin-induced ototoxicity remains a major issue in clinical practice. Experimental evidence indicates that ferroptosis plays a key role in mediating the unwanted cytotoxicity effect caused by cisplatin. However, the role of ferroptosis in cisplatin-induced ototoxicity requires elucidation. Ferrostatin-1 (Fer-1) was identified as a potent inhibitor of ferroptosis and radical-trapping antioxidant with its ability to reduce the accumulation of lipid peroxides and chain-carrying peroxyl radicals. In the current study, we investigated the effects of Fer-1 in cisplatin-induced ototoxicity in in vitro, ex vivo, and in vivo models. We found, for the first time that Fer-1 efficiently alleviated cisplatin-induced cytotoxicity in HEI-OC1 cells via a concentration-dependent manner. Furthermore, Fer-1 mitigated cisplatin cytotoxicity in transgenic zebrafish sensory hair cells. In HEI-OC1 cells, Fer-1 pretreatment not only drastically reduced the generation of intracellular reactive oxygen species but also remarkably decreased lipid peroxidation levels induced by cisplatin. This was not only ascribed to the inhibition of 4-hydroxynonenal, the final product of lipid peroxides, but also to the promotion of glutathione peroxidase 4, the protein marker of ferroptosis. MitoTracker staining and transmission electron microscopy of mitochondrial morphology suggested that in HEI-OC1 cells, Fer-1 can effectively abrogate mitochondrial damage resulting from the interaction with cisplatin. In addition, Fer-1 pretreatment of cochlear explants substantially protected hair cells from cisplatin-induced damage. Therefore, our results demonstrated that ferroptosis might be involved in cisplatin ototoxicity. Fer-1 administration mitigated cisplatin-induced hair cell damage, further investigations are required to elucidate the molecular mechanisms of its otoprotective effect.

CDK7 inhibitor THZ1 enhances antiPD-1 therapy efficacy via the p38α/MYC/PD-L1 signaling in non-small cell lung cancer.

BACKGROUND: The cyclin-dependent kinase 7 (CDK7) subunit of TFIIH regulates RNA polymerase-II-based transcription and promotes tumor progression. However, the mechanisms involved in CDK7-mediated immune evasion are unclear in non-small cell lung cancer (NSCLC). METHODS: RNA silencing and pharmacologic inhibitors were used to evaluate the functions of CDK7/p38α/MYC/PD-L1 axis in cancer cell proliferation and antiPD-1 therapy resistance. Flow cytometry was performed to detect the status of the immune microenvironment after CDK7 inhibition and antiPD-1 therapy in vivo. CD8 depletion antibodies were used to assess the role of CD8+ T cells in combined CDK7 and PD-1 blockade. The associations among CDK7, p38α, MYC, PD-L1, infiltrating T cells, and survival outcomes were validated in two tissue microarrays and public transcriptomic data of NSCLC. RESULTS: High CDK7 mRNA and protein levels were identified to be associated with poor prognosis in NSCLC. CDK7 silencing and CDK7 inhibitor THZ1 elicited apoptosis and suppressed tumor growth. Moreover, CDK7 ablation specifically suppressed p38α/MYC-associated genes, and THZ1 inhibited MYC transcriptional activity through downregulating p38α. CDK7 inhibition sensitized NSCLC to p38α inhibitor. Further, THZ1 suppressed PD-L1 expression by inhibiting MYC activity. THZ1 boosted antitumor immunity by recruiting infiltrating CD8+ T cells and synergized with antiPD-1 therapy. The CDK7/MYC/PD-L1 signature and infiltrating T cell status collectively stratified NSCLC patients into different risk groups. CONCLUSION: These data suggest that the combined CDK7 inhibitor THZ1 and antiPD-1 therapy can be an effective treatment in NSCLC.

Loss of Cardiac Ferritin H Facilitates Cardiomyopathy via Slc7a11-Mediated Ferroptosis.

RATIONALE: Maintaining iron homeostasis is essential for proper cardiac function. Both iron deficiency and iron overload are associated with cardiomyopathy and heart failure via complex mechanisms. Although ferritin plays a central role in iron metabolism by storing excess cellular iron, the molecular function of ferritin in cardiomyocytes remains unknown. OBJECTIVE: To characterize the functional role of Fth (ferritin H) in mediating cardiac iron homeostasis and heart disease. METHODS AND RESULTS: Mice expressing a conditional Fth knockout allele were crossed with 2 distinct Cre recombinase-expressing mouse lines, resulting in offspring that lack Fth expression specifically in myocytes (MCK-Cre) or cardiomyocytes (Myh6-Cre). Mice lacking Fth in cardiomyocytes had decreased cardiac iron levels and increased oxidative stress, resulting in mild cardiac injury upon aging. However, feeding these mice a high-iron diet caused severe cardiac injury and hypertrophic cardiomyopathy, with molecular features typical of ferroptosis, including reduced glutathione (GSH) levels and increased lipid peroxidation. Ferrostatin-1, a specific inhibitor of ferroptosis, rescued this phenotype, supporting the notion that ferroptosis plays a pathophysiological role in the heart. Finally, we found that Fth-deficient cardiomyocytes have reduced expression of the ferroptosis regulator Slc7a11, and overexpressing Slc7a11 selectively in cardiomyocytes increased GSH levels and prevented cardiac ferroptosis. CONCLUSIONS: Our findings provide compelling evidence that ferritin plays a major role in protecting against cardiac ferroptosis and subsequent heart failure, thereby providing a possible new therapeutic target for patients at risk of developing cardiomyopathy.

CDK7 Inhibition is Effective in all the Subtypes of Breast Cancer: Determinants of Response and Synergy with EGFR Inhibition.

CDK7, a transcriptional cyclin-dependent kinase, is emerging as a novel cancer target. Triple-negative breast cancers (TNBC) but not estrogen receptor-positive (ER+) breast cancers have been reported to be uniquely sensitive to the CDK7 inhibitor THZ1 due to the inhibition of a cluster of TNBC-specific genes. However, bioinformatic analysis indicates that CDK7 RNA expression is associated with negative prognosis in all the major subtypes of breast cancer. To further elucidate the effects of CDK7 inhibition in breast cancer, we profiled a panel of cell lines representing different breast cancer subtypes. THZ1 inhibited cell growth in all subtypes (TNBC, HER2+, ER+, and HER2+/ER+) with no apparent subtype selectivity. THZ1 inhibited CDK7 activity and induced G1 arrest and apoptosis in all the tested cell lines, but THZ1 sensitivity did not correlate with CDK7 inhibition or CDK7 expression levels. THZ1 sensitivity across the cell line panel did not correlate with TNBC-specific gene expression but it was found to correlate with the differential inhibition of three genes: CDKN1B, MYC and transcriptional coregulator CITED2. Response to THZ1 also correlated with basal CITED2 protein expression, a potential marker of CDK7 inhibitor sensitivity. Furthermore, all of the THZ1-inhibited genes examined were inducible by EGF but THZ1 prevented this induction. THZ1 had synergistic or additive effects when combined with the EGFR inhibitor erlotinib, with no outward selectivity for a particular subtype of breast cancer. These results suggest a potential broad utility for CDK7 inhibitors in breast cancer therapy and the potential for combining CDK7 and EGFR inhibitors.

Efficacy of retigabine in ameliorating the brain insult following sarin exposure in the rat.

BACKGROUND: Sarin is an irreversible organophosphate cholinesterase inhibitor. Following toxic signs, an extensive long-term brain damage is often reported. Thus, we evaluated the efficacy of a novel anticonvulsant drug retigabine, a modulator of neuronal voltage gated K+ channels, as a neuroprotective agent following sarin exposure. METHODS: Rats were exposed to 1 LD50 or 1.2 LD50 sarin and treated at onset of convulsions with retigabine (5 mg/kg, i.p.) alone or in combination with 5 mg/kg atropine and 7.5 mg/kg TMB-4 (TA) respectively. Brain biochemical and immunohistopathological analyses were processed 24 h and 1 week following 1 LD50 sarin exposure and at 4 weeks following exposure to 1.2 LD50 sarin. EEG activity in freely moving rats was also monitored by telemetry during the first week following exposure to 1.2 LD50 and behavior in the Open Field was evaluated 3 weeks post exposure. RESULTS: Treatment with retigabine following 1 LD50 sarin exposure or in combination with TA following 1.2 LD50 exposure significantly reduced mortality rate compared to the non-treated groups. In both experiments, the retigabine treatment significantly reduced gliosis, astrocytosis and brain damage as measured by translocator protein (TSPO). Following sarin exposure the combined treatment (retigabine+ TA) significantly minimized epileptiform seizure activity. Finally, in the Open Field behavioral test the non-treated sarin group showed an increased mobility which was reversed by the combined treatment. CONCLUSIONS: The M current modulator retigabine has been shown to be an effective adjunct therapy following OP induced convulsion, minimizing epileptiform seizure activity and attenuating the ensuing brain damage.

A combination strategy targeting enhancer plasticity exerts synergistic lethality against BETi-resistant leukemia cells.

Primary and acquired drug resistance imposes a major threat to achieving optimized clinical outcomes during cancer treatment. Aberrant changes in epigenetic modifications are closely involved in drug resistance of tumor cells. Using BET inhibitor (BETi) resistant leukemia cells as a model system, we demonstrated herein that genome-wide enhancer remodeling played a pivotal role in driving therapeutic resistance via compensational re-expression of pro-survival genes. Capitalizing on the CRISPR interference technology, we identified the second intron of IncRNA, PVT1, as a unique bona fide gained enhancer that restored MYC transcription independent of BRD4 recruitment in leukemia. A combined BETi and CDK7 inhibitor treatment abolished MYC transcription by impeding RNAPII loading without affecting PVT1-mediated chromatin looping at the MYC locus in BETi-resistant leukemia cells. Together, our findings have established the feasibility of targeting enhancer plasticity to overcome drug resistance associated with epigenetic therapies.

Pretreatment with Roxadustat (FG-4592) Attenuates Folic Acid-Induced Kidney Injury through Antiferroptosis via Akt/GSK-3ß/Nrf2 Pathway.

Folic acid- (FA-) induced kidney injury is characterized by the tubule damage due to the disturbance of the antioxidant system and subsequent interstitial fibrosis. FG-4592 is an inhibitor of prolyl hydroxylase of hypoxia-inducible factor (HIF), an antioxidant factor. The present study investigated the protective role of FG-4592 pretreatment at the early stage of the kidney injury and long-term impact on the progression of renal fibrosis. FG-4592 was administrated two days before FA injection in mice. On the second day after FA injection, the mice with FG-4592 pretreatment showed an improved renal function, compared with those without FG-4592 pretreatment, indicated by biochemical and histological parameters; meanwhile, the cellular content of iron, malondialdehyde, and 4-hydroxynonenal histologically decreased, implying the suppression of iron accumulation and lipid peroxidation. Simultaneously, upregulation of HIF-1α was found, along with Nrf2 activation, which was reflected by increased nuclear translocation and high-expression of downstream proteins, including heme-oxygenase1, glutathione peroxidase4, and cystine/glutamate transporter, as well as ferroportin. Correspondingly, the elevated levels of antioxidative enzymes and glutathione, as well as reduced iron accumulation, were observed, suggesting a lower risk of occurrence of ferroptosis with FG-4592 pretreatment. This was confirmed by reversed pathological parameters and improved renal function in FA-treated mice with the administration of ferrostatin-1, a specific ferroptosis inhibitor. Furthermore, a signal pathway study indicated that Nrf2 activation was associated with increased phosphorylation of Akt and GSK-3ß, verified by the use of an inhibitor of the PI3K that phosphorylates Akt. Moreover, FG-4592 pretreatment also decreased macrophage infiltration and expression of inflammatory factors TNF-α and IL-1ß. On the 14th day after FA injection, FG-4592 pretreatment decreased collagen deposition and expression of fibrosis biomarkers. These findings suggest that the protective role of FG-4592 pretreatment is achieved mainly by decreasing ferroptosis at the early stage of FA-induced kidney injury via Akt/GSK-3ß-mediated Nrf2 activation, which retards the fibrosis progression.

The covalent CDK7 inhibitor THZ1 enhances temsirolimus-induced cytotoxicity via autophagy suppression in human renal cell carcinoma.

Renal cell carcinoma (RCC) is a major cancer of the kidney. The 5-year survival rate is overall 74% and only 8% for Stage 4 cancers. Several agents including tyrosine kinase inhibitors, mTOR inhibitors, and immune checkpoint inhibitors are available as first- or second-line therapy for metastatic RCC. However, the survival benefits are limited. Recently, THZ1 has been identified as a cyclin-dependent kinase 7 (CDK7) inhibitor that interferes with the transcriptional machinery. Although it is apparently effective in various cancer models, the data for RCC has never been reported. In this study, we demonstrated the impact of CDK7 expression on tumor progression and patient survival in a clinical cohort. We found that THZ1 induced apoptosis and cell cycle arrest in RCC cells, thereby reducing cell viability. Furthermore, THZ1 acted synergistically with temsirolimus in vitro, probably by inhibiting autophagy. Moreover, compared to either THZ1 or temsirolimus used individually, the combination treatment further suppressed tumor growth in vivo. These results indicate that CDK7 is associated with the progression and prognosis of RCC, and is a potential therapeutic target for overcoming drug resistance in this cancer.

Safety of retigabine in adults with partial-onset seizures after long-term exposure: focus on unexpected ophthalmological and dermatological events.

BACKGROUND: Retigabine is an antiepileptic drug developed for the adjunctive treatment of adults with epilepsy and partial-onset seizures (POS). Following its approval in 2011, reports of ophthalmological/dermatological pigmentation/discoloration led to a restriction of the indication in 2013, and in 2017, retigabine was voluntarily withdrawn from the market because of its limited usage. Here, data are reported from four open-label extension studies focusing on long-term safety with particular emphasis on ophthalmological and dermatological events. METHODS: Studies 113413 (NCT01336621), 114873 (NCT01777139), 115097 (NCT00310388), and 115098 (NCT00310375) were multicenter, open-label extension studies of retigabine (300-1200 mg/day) for the adjunctive treatment of adults with POS. Safety assessments included monitoring treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs). When new safety issues were identified, protocols were amended to include additional on-treatment safety evaluations, including ophthalmological and dermatological examinations. Patients who had abnormal retinal pigmentation, unexplained vision change, pigmentation of nonretinal ocular tissue, or abnormal discoloration of skin, lips, nails, and/or mucosa at the end of the treatment phase were asked to enter a safety follow-up continuation phase comprising 6-monthly ophthalmological/dermatological assessments. RESULTS: The safety population (patients receiving ≥1 dose of retigabine in the open-label phase) comprised 98, 30, 376, and 181 patients for studies 113413, 114873, 115097, and 115098, respectively. Mean (standard deviation) treatment exposure ranged from 529 (424) to 1129 (999) days. In total, 68%-96% and 4%-27% of patients across the studies experienced TEAEs and TE SAEs, respectively. There were seven on-treatment deaths and two after discontinuation. Overall, 14%-73% of patients had an on-treatment eye examination, of whom 8/53, 4/22, 17/54, and 14/36 had abnormal retinal pigmentation and 15/53, 7/22, 15/54, and 11/36 had nonretinal ocular pigmentation in studies 113413, 114873, 115097, and 115098, respectively. Four patients had confirmed acquired vitelliform maculopathy. In patients with unresolved events at discontinuation and ≥1 posttreatment follow-up, retinal pigmentation resolved completely in 1/3, 0/3, 0/10, and 1/7 patients and nonretinal ocular pigmentation in 1/4, 0/3, 8/10, and 4/6 patients, respectively. Overall, 12%-83% of patients had an on-treatment dermatological examination, of whom 11/58, 0/25, 23/46, and 23/37 had any-tissue discoloration, respectively. In patients with unresolved events at discontinuation and ≥1 posttreatment follow-up, discoloration of skin, lips, nails, and/or mucosa resolved completely in 2/3, 0/0, 7/13, and 1/11 patients, respectively. CONCLUSIONS: The safety profile of retigabine in adults with POS across four open-label studies was generally consistent with data from previous placebo-controlled studies. Discoloration of various tissues occurred in a proportion of patients treated with retigabine and resolved completely in a small number of these patients following treatment discontinuation. In addition, comprehensive eye examination identified a new adverse reaction of acquired vitelliform maculopathy in a limited number of patients.

CDK7 Inhibition Suppresses Castration-Resistant Prostate Cancer through MED1 Inactivation.

Metastatic castration-resistant prostate cancer (CRPC) is a fatal disease, primarily resulting from the transcriptional addiction driven by androgen receptor (AR). First-line CRPC treatments typically target AR signaling, but are rapidly bypassed, resulting in only a modest survival benefit with antiandrogens. Therapeutic approaches that more effectively block the AR-transcriptional axis are urgently needed. Here, we investigated the molecular mechanism underlying the association between the transcriptional coactivator MED1 and AR as a vulnerability in AR-driven CRPC. MED1 undergoes CDK7-dependent phosphorylation at T1457 and physically engages AR at superenhancer sites, and is essential for AR-mediated transcription. In addition, a CDK7-specific inhibitor, THZ1, blunts AR-dependent neoplastic growth by blocking AR/MED1 corecruitment genome-wide, as well as reverses the hyperphosphorylated MED1-associated enzalutamide-resistant phenotype. In vivo, THZ1 induces tumor regression of AR-amplified human CRPC in a xenograft mouse model. Together, we demonstrate that CDK7 inhibition selectively targets MED1-mediated, AR-dependent oncogenic transcriptional amplification, thus representing a potential new approach for the treatment of CRPC. SIGNIFICANCE: Potent inhibition of AR signaling is critical to treat CRPC. This study uncovers a driver role for CDK7 in regulating AR-mediated transcription through phosphorylation of MED1, thus revealing a therapeutically targetable potential vulnerability in AR-addicted CRPC.See related commentary by Russo et al., p. 1490.This article is highlighted in the In This Issue feature, p. 1469.

A seven-year retrospective analysis of patch test data in a cohort of patients with contact dermatitis in Sri Lanka.

BACKGROUND: Patch testing with a baseline series is a common tool employed when the sensitizing agent in contact dermatitis is unclear. However, for Asian countries, there are no locally validated baseline series to utilize in screening. METHODS: We completed a retrospective analysis of all patients that had undergone patch testing with the European Baseline series, Shoe Series or Comprehensive International Baseline series, over 7 years from 2012 to 2018 in a tertiary care reference dermatology clinic in Sri Lanka to evaluate the suitability of these investigations to identify causes for contact dermatitis in the local study population. RESULTS: Out of 438 patients tested, 239 (54.8%) reacted to at least one substance in the series. The Shoe Series was significantly more likely to yield a positive result than the European Baseline Series (70.2% vs 46.9%, p < 0.05). The top three sensitizers identified by all series were nickel sulfate (16%, 70/438), p-phenylenediamine (12.3%, 54/438) and 2-mercaptobenzothiazole or mercapto mix (10.5%, 46/438). CONCLUSION: Shoe series has a comparatively high yield in the local population compared to European Baseline series. Since little less than half of the study population did not have any reactivity to any of the allergens tested it is important to develop or modify and validate a locally relevant, more suitable baseline series which is based on the Shoe Series in Sri Lanka. This is further evidence for the continuously changing nature of allergens in the environment and the need to modify existing patch testing standards accordingly.