Possible effects of plasminogen activator inhibitor-1 on promoting angiogenesis through matrix metalloproteinase 9 in advanced mycosis fungoides.

Mycosis fungoides (MF) progresses slowly before advancing to skin tumors followed by lymph node and visceral involvement. Among MF progression, stage IIB is an initial time point of tumor formation in MF. Since MF in tumor stage possess abundant blood vessels, it is important to evaluate the pro-angiogenic factors before and after MF in stage IIB. In this report, we investigated pro-angiogenic soluble factors in MF patients, as well as its pro-angiogenetic effects on tumor cells and stroma cells. We first evaluated the serum levels of pro-angiogenic factors in 9 MF patients without tumor formation and 8 MF patients with tumor formation. Among them, the serum MMP-9 and plasminogen activator inhibitors 1 (PAI-1) was significantly increased in MF with tumor formation compared in MF without tumor formation, leading to favorable formation of human dermal microvascular endothelial cells tube networks. Moreover, PAI-1 stimulation significantly increased the mRNA expression and protein production MMP-9 on monocytes derived M2 macrophages and HUT-78. Furthermore, since MMP-9 production from tumor cells as well as stromal cells is suppressed by bexarotene, we evaluate the baseline serum pro-angiogenic factors including MMP-9 in 16 patients with advanced cutaneous T cell lymphoma treated with bexarotene. The serum levels of MMP-2 and MMP-9 was significantly increased in bexarotene non-responded patients compared to responded patients. Our present study suggested the significance of MMP-9 and PAI-1 for the progression of MF stage toward to the tumor stage, and could be a therapeutic target in future.

Bexarotene leads to durable improvements in visual evoked potential latency: A follow-up study of the Cambridge Centre for Myelin Repair One trial.

The Cambridge Centre for Myelin Repair One (CCMR-One) trial showed that 6 months of bexarotene reduces visual evoked potential (VEP) latency in people with relapsing-remitting multiple sclerosis (MS). In a single-centre follow-up study of these participants, we re-examined full-field VEP and clinical assessments. Twenty participants (12 bexarotene and 8 placebo) were seen on average 27 months after their trial involvement. In an analysis of all eyes with recordable signal (24 bexarotene and 14 placebo), the adjusted bexarotene-placebo treatment difference in P100 latency was -7.79 (95% confidence interval (CI) = -14.76, -0.82) ms, p = 0.044. We conclude that there were durable improvements in VEP latency, suggesting long-term benefits from exposure to a remyelinating drug.

Bexarotene-induced hypothyroidism and dyslipidemia; a nation-wide study.

Central hypothyroidism and dyslipidemia are well-known adverse events (AEs) of bexarotene therapy. Although hypothyroidism is known to cause dyslipidemia, no study has examined the association between hypothyroidism and dyslipidemia in patients undergoing bexarotene therapy. The aim of this study is to examine this association. A retrospective observational study was performed among 294 patients who initiated bexarotene therapy in Japan (nation-wide postmarketing complete surveillance). Jonckheere-Terpstra (one sided) test was performed to evaluate the effect of the bexarotene dose on lipid metabolisms, and regression analyses were performed to evaluate associations of bexarotene dose, free thyroxine (FT4), body mass index (BMI), and lipid metabolisms. Most patients developed hypothyroidism. Two-third of patients showed FT4 values below the lower limit at 1 week. Triglycerides (TG) increased in a bexarotene dose-dependent manner, and grade ≥3 AEs on hypertriglyceridemia was observed in 39% of the patients. Additionally, one-third of grade ≥3 AEs on hypertriglyceridemia occurred within 1 week. The delta_FT4 (difference in FT4 from baseline) negatively correlated with TG increase at 1 week (p = 0.012) but not with low density lipoprotein cholesterol (LDL-C) increase at any week. Bexarotene-induced hypothyroidism is almost inevitable and occurred quickly. Bexarotene-induced hypertriglyceridemia showed positive bexarotene dose dependency and negative delta_FT4 dependency. Prophylactic and appropriate thyroid hormone compensation therapy and starting bexarotene at low doses with subsequent titration while managing dyslipidemia may have a beneficial effect for the successful continuation of bexarotene therapy without severe endocrine and metabolic AEs.

Experience With Bexarotene to Treat Cutaneous T-Cell Lymphomas: A Study of the Spanish Working Group of Cutaneous Lymphomas. / [Artículo traducido] Experiencia con bexaroteno en linfoma cutáneo de células T: un estudio del Grupo Español de Linfomas Cutáneos (GELC).

BACKGROUND AND OBJECTIVES: Bexarotene has been approved to treat advanced stage cutaneous T-cell lymphomas (CTCL) since 1999. However, very few data have been published on its long-term safety and efficacy profile. The aim of this study is to determine the tolerability to bexarotene and outcomes by collecting the 2nd largest case series to date on its long-term use vs CTCL. MATERIAL AND METHOD: This was a multicenter retrospective review of 216 patients with mycosis fungoides (174), or Sézary syndrome (42) on a 10-year course of bexarotene alone or in combination with other therapies at 19 tertiary referral teaching hospitals. RESULTS: A total of 133 men (62%) and 83 women (38%) were included, with a mean age of 63.5 year (27-95). A total of 45% were on bexarotene monotherapy for the entire study period, 22% started on bexarotene but eventually received an additional therapy, 13% were on another treatment but eventually received bexarotene while the remaining 20% received a combination therapy since the beginning. The median course of treatment was 20.78 months (1-114); and the overall response rate, 70.3%. Complete and partial response rates were achieved in 26% and 45% of the patients, respectively. Treatment was well tolerated, being the most common toxicities hypertriglyceridemia (79%), hypercholesterolemia (71%), and hypothyroidism (52%). No treatment-related grade 5 adverse events were reported. CONCLUSIONS: Our study confirms bexarotene is a safe and effective therapy for the long-term treatment of CTCL.

Experience With Bexarotene to Treat Cutaneous T-Cell Lymphomas: A Study of the Spanish Working Group of Cutaneous Lymphomas.

BACKGROUND AND OBJECTIVES: Bexarotene has been approved to treat advanced stage cutaneous T-cell lymphomas (CTCL) since 1999. However, very few data have been published on its long-term safety and efficacy profile. The aim of this study is to determine the tolerability to bexarotene and outcomes by collecting the 2nd largest case series to date on its long-term use vs CTCL. MATERIAL AND METHOD: This was a multicenter retrospective review of 216 patients with mycosis fungoides (174), or Sézary syndrome (42) on a 10-year course of bexarotene alone or in combination with other therapies at 19 tertiary referral teaching hospitals. RESULTS: A total of 133 men (62%) and 83 women (38%) were included, with a mean age of 63.5 year (27-95). A total of 45% were on bexarotene monotherapy for the entire study period, 22% started on bexarotene but eventually received an additional therapy, 13% were on another treatment but eventually received bexarotene while the remaining 20% received a combination therapy since the beginning. The median course of treatment was 20.78 months (1-114); and the overall response rate, 70.3%. Complete and partial response rates were achieved in 26% and 45% of the patients, respectively. Treatment was well tolerated, being the most common toxicities hypertriglyceridemia (79%), hypercholesterolemia (71%), and hypothyroidism (52%). No treatment-related grade 5 adverse events were reported. CONCLUSIONS: Our study confirms bexarotene is a safe and effective therapy for the long-term treatment of CTCL.

Bexarotene drives the self-renewing proliferation of adult neural stem cells, promotes neuron-glial fate shift, and regulates late neuronal differentiation.

Treatment with bexarotene, a selective retinoid X receptor (RXR) agonist, significantly improves behavioral dysfunctions in various neurodegenerative animal models. Additionally, it activates neurodevelopmental and plasticity pathways in the brains of adult mice. Our objective was to investigate the impact of RXR activation by bexarotene on adult neural stem cells (aNSC) and their cell lineages. To achieve this, we treated NSCs isolated from the subventricular zone (SVZ) of adult rat brains from the proliferative stage to the differentiated status. The results showed that bexarotene-treated aNSC exhibited increased BrdU incorporation, SOX2+ dividing cell pairs, and cell migration from neurospheres, revealing that the treatment promotes self-renewing proliferation and cell motility in SVZ-aNCS. Furthermore, bexarotene induced a cell fate shift characterized by a significant increase in GFAP+/S100B+ differentiated astrocytes, which uncovers the participation of activated-RXR in astrogenesis. In the neuronal lineage, the fate shift was counteracted by bexarotene-induced enhancement of NeuN+ nuclei together with neurite network outgrowth, indicating that the RXR agonist stimulates SVZ-aNCS neuronal differentiation at later stages. These findings establish new connections between RXR activation, astro- and neurogenesis in the adult brain, and contribute to the development of therapeutic strategies targeting nuclear receptors for neural repair.

In vitro-in vivo extrapolation of bexarotene metabolism in the presence of chronic kidney disease and acute kidney injury in rat using physiologically based pharmacokinetic modeling and extrapolation to human.

Renal impairment can affect the elimination of hepatically metabolized drugs. Bexarotene (BXT) used for cutaneous T-cell lymphoma is highly bound in plasma and metabolized by CYP3A4. The BXT European Medicine Agency and Food and Drug Administration packages recommended the evaluation of renal impairment on BXT metabolism. The plasma protein binding of BXT can be changed in patients with renal dysfunction due to hypoalbuminemia and accumulation of uremic toxins. In vitro, microsomal stability and plasma protein binding studies were pursued. A preclinical pharmacokinetic study was pursued in control, chronic kidney disease (CKD), and acute kidney injury (AKI) rats. A BXT physiologically based pharmacokinetic (PBPK) model that utilized in vitro-in vivo extrapolation of metabolism was established and verified in healthy rats, customized to CKD and AKI rats, and extrapolated to healthy human subjects and those with CKD stages 3, 4, and 5. In vitro studies showed that AKI and CKD significantly increased the BXT fraction unbound in plasma (from 0.011 to 0.018 and 0.022, respectively) and decreased intrinsic clearance (from 4.1 to 2.5, and 2.2 mL/min/g liver, respectively). This could explain the reduced in vivo clearance observed in CKD rats (from 0.4 to 0.28 L/h/kg) and the 1.3-fold increase in BXT exposure. Changes in BXT disposition in AKI rats were not straightforward due to simultaneous changes in BXT distribution. The human PBPK model predicted an increased BXT exposure by 2-fold in CKD patients, suggesting the need for dose reduction and drug monitoring. The reduced BXT metabolism due to renal impairment is especially relevant in cancer patients with CKD.

Automated production of 11 C-labeled carboxylic acids and esters via "in-loop" 11 C-carbonylation using GE FX synthesis modules.

An in-loop 11 C-carbonylation process for the radiosynthesis of 11 C-carboxylic acids and esters from halide precursors has been developed. The reaction proceeds at room temperature under mild conditions and enables 11 C-carbonylation of both electron deficient and electron rich (hetero)aromatic halides to provide 11 C-carboxylic acids and esters in good to excellent radiochemical yields, high radiochemical purity, and excellent molar activity. The process has been fully automated using commercial radiochemistry synthesis modules, and application to clinical production is demonstrated via validated cGMP radiosyntheses of [11 C]bexarotene and [11 C]acetoacetic acid.

A Biomimetic Multiparametric Assay to Characterise Anti-Amyloid Drugs.

Alzheimer's disease (AD) is the most widespread form of senile dementia worldwide and represents a leading socioeconomic problem in healthcare. Although it is widely debated, the aggregation of the amyloid ß peptide (Aß) is linked to the onset and progression of this neurodegenerative disease. Molecules capable of interfering with specific steps in the fibrillation process remain of pharmacological interest. To identify such compounds, we have set up a small molecule screening process combining multiple experimental methods (UV and florescence spectrometry, ITC, and ATR-FTIR) to identify and characterise potential modulators of Aß1-42 fibrillation through the description of the biochemical interactions (molecule-membrane Aß peptide). Three known modulators, namely bexarotene, Chicago sky blue and indomethacin, have been evaluated through this process, and their modulation mechanism in the presence of a biomembrane has been described. Such a well-adapted physico-chemical approach to drug discovery proves to be an undeniable asset for the rapid characterisation of compounds of therapeutic interest for Alzheimer's disease. This strategy could be adapted and transposed to search for modulators of other amyloids such as tau protein.

Bexarotene-induced central hypothyroidism assessed by TRH stimulation test in cutaneous T-cell lymphoma patients.

Bexarotene-induced central hypothyroidism (CH), for which levothyroxine (LT4) replacement is recommended, has been shown to be caused by pituitary but not hypothalamic disorder experimentally, though the underlying mechanism in humans remains unclear. Here, the pathophysiology of bexarotene-induced CH was examined using a TRH stimulation test in cutaneous T-cell lymphoma (CTCL) patients. In this retrospective longitudinal observational study, serum TSH and free T4 (F-T4) levels were measured in 10 euthyroid patients with CTCL during 24 weeks of bexarotene treatment. TRH stimulation testing was performed following CH diagnosis, with LT4 replacement dosage adjusted to maintain F-T4 at the pre-treatment level. After one week of bexarotene administration, all 10 patients developed CH, based on combined findings of low or low-normal F-T4 with low or normal TSH levels. TSH peak response after a stimulation test at one week was reached at 30 minutes. However, that was <4 µIU/mL in all patients, indicating a blunted though not exaggerated and delayed TSH response. In eight who continued bexarotene for 24 weeks, median LT4 replacement dosage was 125 (range, 75-150) µg/day. TSH level at 30 as well as 15, 60, 90, and 120 minutes after TRH stimulation was significantly correlated with LT4 replacement dosage (ρ = -0.913, p = 0.002), whereas TSH and F-T4 basal levels at one week were not. These results suggest that pituitary hypothyroidism is responsible for bexarotene-induced CH, while TSH levels after TRH stimulation precisely reflect residual pituitary-thyroid function in patients receiving bexarotene.

The Use of Retinoids for the Prevention and Treatment of Skin Cancers: An Updated Review.

Retinoids are natural and synthetic vitamin A derivatives that are effective for the prevention and the treatment of non-melanoma skin cancers (NMSC). NMSCs constitute a heterogenous group of non-melanocyte-derived skin cancers that impose substantial burdens on patients and healthcare systems. They include entities such as basal cell carcinoma and cutaneous squamous cell carcinoma (collectively called keratinocyte carcinomas), cutaneous lymphomas and Kaposi's sarcoma among others. The retinoid signaling pathway plays influential roles in skin physiology and pathology. These compounds regulate diverse biological processes within the skin, including proliferation, differentiation, angiogenesis and immune regulation. Collectively, retinoids can suppress skin carcinogenesis. Both topical and systemic retinoids have been investigated in clinical trials as NMSC prophylactics and treatments. Desirable efficacy and tolerability in clinical trials have prompted health regulatory bodies to approve the use of retinoids for NMSC management. Acceptable off-label uses of these compounds as drugs for skin cancers are also described. This review is a comprehensive outline on the biochemistry of retinoids, their activities in the skin, their effects on cancer cells and their adoption in clinical practice.

iTRAQ-derived quantitative proteomics uncovers the neuroprotective property of bexarotene in a mice model of cerebral ischemia-reperfusion injury.

Bexarotene, a FDA-approved drug for cutaneous lymphoma, has been shown to exert brain protective effects. In previous study, we demonstrated that Bexarotene protects against cerebral ischemic stroke by suppressing the JNK/Caspase-3 signaling pathway. However, the molecular mechanisms by which Bexarotene-mediated neuroprotective are not fully understood. Based on the isobaric tags for relative and absolute quantification (iTRAQ)-derived proteomics and bioinformatics analysis, 4,454 differentially expressed proteins (DEPs) were identified in upstream of the JNK signaling pathway. Among them, 149 DEPs showed aberrant expression in the vehicle-versus Bexarotene-treated mice. DEPs were primarily enriched in the metabolism, calcium, and MAPK signaling pathways. The largest DEP increase was seen with heat shock protein HSP 70, whereas the largest DEP decrease was seen with JNK scaffold protein JIP3, both of which are involved in the MAPK network. Furthermore, we illustrated the Bexarotene obviously abolished oxygen and glucose deprivation/reperfusion (OGD/R)- induced LDH leakage, cells apoptosis, and the protein expression level of the JIP3,p-ASK1, p-JNK, and Cleaved Caspase3. Together, these results suggest a potential neuroprotective role of Bexarotene via inhibition of the JIP3/ASK1/JNK/Caspase 3 signaling pathway.

Ex Vivo Investigation of Bexarotene and Nicotinamide Function as a Protective Agent on Rat Synaptosomes Treated with Aß(1-42).

In this study, we were aimed to investigate the neuroprotective effects of bexarotene and nicotinamide in synaptosomes incubated with amyloid-beta (Aß). Our study consists of 2 parts, in vivo and in vitro. In the in vivo section, twenty-four Wistar albino male rats were divided into 4 groups (control, dimethyl sulfoxide (DMSO), nicotinamide and bexarotene) with six animals in each group. DMSO(1%), nicotinamide(100 mg/kg) and bexarotene(0.1 mg/kg) were administered intraperitoneally to animals in the experimental groups for seven days. In the in vitro part of our study, three different isolation methods were used to obtain the synaptosomes from the brain tissue. Total antioxidant capacity(TAS), total oxidant capacity(TOS), cleaved caspase 3(CASP3), cytochrome c(Cyt c), sirtuin 1(SIRT1), peroxisome proliferator-activated receptor gamma(PPARγ) and poly(ADP-ribose) polymerase-1(PARP-1) levels in the synaptosomes incubated with a concentration of 10 µM Aß(1-42) were measured by enzyme-linked immunosorbent assay method. Biochemical analysis and histopathological examinations in serum and brain samples showed that DMSO, nicotinamide and bexarotene treatments did not cause any damage to the rat brain tissue. We found that in vitro Aß(1-42) administration decreased TAS, SIRT1 and PPARγ levels in synaptosomes while increasing TOS, CASP3, Cyt c, and PARP1 levels. Nicotinamide treatment suppressed oxidative stress and apoptosis by supporting antioxidant capacity and increased PPARγ through SIRT1 activation, causing PARP1 to decrease. On the other hand, bexarotene caused a moderate increase in SIRT1 levels with PPARγ activation. Consequently, we found that nicotinamide can be more effective than bexarotene in AD pathogenesis by regulating mitochondrial functions in synaptosomes.

Suppression of TLR4/MyD88/TAK1/NF-κB/COX-2 Signaling Pathway in the Central Nervous System by Bexarotene, a Selective RXR Agonist, Prevents Hyperalgesia in the Lipopolysaccharide-Induced Pain Mouse Model.

A selective RXR agonist, bexarotene, has been shown to have anti-inflammatory, anti-nociceptive, and neuroprotective effects in several models of numerous neurological diseases characterized by systemic inflammation. The mechanisms underlying these effects remains unknown. To elucidate these mechanisms, we investigated whether the TLR4/MyD88/TAK1/NF-κB/COX-2 signaling pathway in the CNS mediates the effect of bexarotene to prevent hyperalgesia in the LPS-induced inflammatory pain mouse model. The reaction time to thermal stimuli within 30 s was evaluated by the hot plate test in male mice treated with saline, LPS (10 mg/kg), DMSO, and/or bexarotene (0.1, 1, 3, or 10 mg/kg) after 6 h. The latency to the thermal stimulus (18.11 ± 1.36 s) in the LPS-treated mice was significantly decreased by 30% compared with saline-treated mice (25.84 ± 1.99 s). Treatment with bexarotene only at a dose of 10 mg/kg showed a significant increase in the latency by 22.49 ± 1.00 s compared with LPS-treated mice. Bexarotene also prevented the reduction in RXRα protein expression associated with a rise in the expression of TLR4, MyD88, phosphorylated TAK1, NF-κB p65, phosphorylated NF-κB p65, COX-2, and IL-1ß proteins, in addition to COX-2 activity and levels of PGE2 and IL-1ß in the brains and spinal cords of the LPS-treated animals. Likely, decreased activity of TLR4/MyD88/TAK1/NF-κB/COX-2 signaling pathway in addition to increased pro-inflammatory cytokine formation in the CNS of mice participates in the protective effect of bexarotene against hyperalgesia induced by LPS.

Synthetic Retinoids as Potential Therapeutics in Prostate Cancer-An Update of the Last Decade of Research: A Review.

Prostate cancer (PC) is the second most common tumor in males. The search for appropriate therapeutic options against advanced PC has been in process for several decades. Especially after cessation of the effectiveness of hormonal therapy (i.e., emergence of castration-resistant PC), PC management options have become scarce and the prognosis is poor. To overcome this stage of disease, an array of natural and synthetic substances underwent investigation. An interesting and promising class of compounds constitutes the derivatives of natural retinoids. Synthesized on the basis of the structure of retinoic acid, they present unique and remarkable properties that warrant their investigation as antitumor drugs. However, there is no up-to-date compilation that consecutively summarizes the current state of knowledge about synthetic retinoids with regard to PC. Therefore, in this review, we present the results of the experimental studies on synthetic retinoids conducted within the last decade. Our primary aim is to highlight the molecular targets of these compounds and to identify their potential promise in the treatment of PC.

Bexarotene Enhances Macrophage Erythrophagocytosis and Hematoma Clearance in Experimental Intracerebral Hemorrhage.

Background and Purpose- Enhancement of erythrophagocytosis by macrophages in a timely manner can limit the toxic effects of erythrocyte metabolites and promote brain recovery after intracerebral hemorrhage (ICH). In the current study, we investigated the therapeutic effect of retinoid X receptor agonist, bexarotene, in facilitating erythrophagocytosis and neurobehavioral recovery in 2 mouse models of ICH. Methods- Bone marrow-derived macrophages and fluorescently labeled erythrocytes were used to study erythrophagocytosis in vitro with phenotypic changes quantified by gene expression. ICH was modeled in vivo using intrastriatal autologous blood and collagenase injection in mice with and without bexarotene treatment beginning 3 hours after ICH. In vivo phagocytosis, ability and hematoma clearance were evaluated by erythrophagocytosis assays, flow cytometry, and histological analysis. Neurological deficits and functional recovery were also quantified. Results- Bexarotene increased macrophage expression of phagocytosis receptors and erythrophagocytosis and reduced macrophage TNF (tumor necrosis factor) production in vitro. In vivo, bexarotene treatment enhanced erythrophagocytosis, reduced hematoma volume, and ultimately improved neurological recovery after ICH in 2 distinct models of ICH. Conclusions- Bexarotene administration is beneficial for recovery after ICH by enhancing hemorrhage phagocytosis, modulating macrophage phenotype, and improving functional recovery.

Bexarotene - a novel modulator of AURKA and the primary cilium in VHL-deficient cells.

Loss of the gene von Hippel-Lindau (VHL) is associated with loss of primary cilia and is causally linked to elevated levels of Aurora kinase A (AURKA). We developed an image-based high-throughput screening (HTS) assay using a dual-labeling image analysis strategy that identifies both the cilium and the basal body. By using this strategy, we screened small-molecule compounds for the targeted rescue of cilia defects associated with VHL deficiency with high accuracy and reproducibility. Bexarotene was identified and validated as a positive regulator of the primary cilium. Importantly, the inability of an alternative retinoid X receptor (RXR) agonist to rescue ciliogenesis, in contrast to bexarotene, suggested that multiple bexarotene-driven mechanisms were responsible for the rescue. We found that bexarotene decreased AURKA expression in VHL-deficient cells, thereby restoring the ability of these cells to ciliate in the absence of VHL Finally, bexarotene treatment reduced the propensity of subcutaneous lesions to develop into tumors in a mouse xenograft model of renal cell carcinoma (RCC), with a concomitant decrease in activated AURKA, highlighting the potential of bexarotene treatment as an intervention strategy in the clinic to manage renal cystogenesis associated with VHL deficiency and elevated AURKA expression.

Bexarotene Improve Depression-Like Behaviour in Mice by Protecting Against Neuro-inflammation and Synaptic Damage.

The growing number of evidences suggest that neuroinflammation and synaptic damage are closely related to the onset of depression. Bexarotene (Bex), a retinoid X receptor agonist, is an U.S. Food and Drug Administration-approved drug for the treatment of cutaneous T-cell lymphoma that has recently been reported to have anti-inflammatory and neuroprotective effects in several models of neurological disease including Parkinson's disease, Alzheimer's disease, and so forth. However, the effect of Bex on depression remains unclear. In this study, we investigated effect of Bex on depression-like behaviour in mice induced by lipopolysaccharide (LPS) or corticosterone (CORT). Our results showed that treatment with Bex for 15 days significantly improved LPS-induced depression-like behaviour in social interaction test and CORT-induced depression-like behaviour in forced swimming test and tail suspension test in mice. We found that the Bex treatment depressed the increase in the number of activated microglia and astrocytes in the frontal cortex, and the increase in the levels of inflammatory cytokines TNF-α, IL-1ß and IL-6 in LPS-injected mice. Furthermore, Bex treatment also rescued the decrease in the expression of BDNF, and inhibition of CREB/BDNF/ERK pathway, and improved the expression of synaptic related protein in CORT-induced mice. Based on these results, it is possible that Bex reversed depression-like behaviour in mice by reducing neuroinflammation and protecting against synaptic damage induced by LPS or CORT.

Discovery of the FDA-approved drugs bexarotene, cetilistat, diiodohydroxyquinoline, and abiraterone as potential COVID-19 treatments with a robust two-tier screening system.

Coronavirus Disease 2019 (COVID-19) caused by the emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with a crude case fatality rate of about 0.5-10 % depending on locality. A few clinically approved drugs, such as remdesivir, chloroquine, hydroxychloroquine, nafamostat, camostat, and ivermectin, exhibited anti-SARS-CoV-2 activity in vitro and/or in a small number of patients. However, their clinical use may be limited by anti-SARS-CoV-2 50 % maximal effective concentrations (EC50) that exceeded their achievable peak serum concentrations (Cmax), side effects, and/or availability. To find more immediately available COVID-19 antivirals, we established a two-tier drug screening system that combines SARS-CoV-2 enzyme-linked immunosorbent assay and cell viability assay, and applied it to screen a library consisting 1528 FDA-approved drugs. Cetilistat (anti-pancreatic lipase), diiodohydroxyquinoline (anti-parasitic), abiraterone acetate (synthetic androstane steroid), and bexarotene (antineoplastic retinoid) exhibited potent in vitro anti-SARS-CoV-2 activity (EC50 1.13-2.01 µM). Bexarotene demonstrated the highest Cmax:EC50 ratio (1.69) which was higher than those of chloroquine, hydroxychloroquine, and ivermectin. These results demonstrated the efficacy of the two-tier screening system and identified potential COVID-19 treatments which can achieve effective levels if given by inhalation or systemically depending on their pharmacokinetics.

Optimized Bexarotene Aerosol Formulation Inhibits Major Subtypes of Lung Cancer in Mice.

Bexarotene has shown inhibition of lung and mammary gland tumorigenesis in preclinical models and in clinical trials. The main side effects of orally administered bexarotene are hypertriglyceridemia and hypercholesterolemia. We previously demonstrated that aerosolized bexarotene administered by nasal inhalation has potent chemopreventive activity in a lung adenoma preclinical model without causing hypertriglyceridemia. To facilitate its future clinical translation, we modified the formula of the aerosolized bexarotene with a clinically relevant solvent system. This optimized aerosolized bexarotene formulation was tested against lung squamous cell carcinoma mouse model and lung adenocarcinoma mouse model and showed significant chemopreventive effect. This new formula did not cause visible signs of toxicity and did not increase plasma triglycerides or cholesterol. This aerosolized bexarotene was evenly distributed to the mouse lung parenchyma, and it modulated the microenvironment in vivo by increasing the tumor-infiltrating T cell population. RNA sequencing of the lung cancer cell lines demonstrated that multiple pathways are altered by bexarotene. For the first time, these studies demonstrate a new, clinically relevant aerosolized bexarotene formulation that exhibits preventive efficacy against the major subtypes of lung cancer. This approach could be a major advancement in lung cancer prevention for high risk populations, including former and present smokers.