Roflumilast Attenuates Microglial Senescence and Retinal Inflammatory Neurodegeneration Post Retinal Ischemia Reperfusion Injury Through Inhibiting NLRP3 Inflammasome.

Purpose: Retinal ischemia-reperfusion (RIR) injury is implicated in various retinal diseases, leading to retinal ganglion cells (RGCs) degeneration. Microglial senescence exacerbates inflammation, contributing to neurodegeneration. This study aimed to investigate the potential therapeutic role of Roflumilast (Roflu) in ameliorating microglial senescence and neuroinflammation following RIR injury. Methods: C57BL/6J mice underwent RIR surgery, and Roflu treatment was administered intraperitoneally. BV2 microglial cells were subjected to oxygen-glucose deprivation and reoxygenation (OGD/R) to simulate ischemic conditions in vitro. SA-ß-gal staining was used to detect cellular senescence. Quantitative PCR and ELISA were used to examine the levels of senescence-associated secretory phenotype (SASP) factors. Hematoxylin and eosin (H&E) staining was performed on retinal sections to assess retinal morphology and thickness. Surviving RGCs were labeled and quantified in retinal whole-mounts using immunofluorescence (IF). Furthermore, Western blot and IF staining were used to quantify the proteins associated with the cell cycle and NLRP3 inflammasomes. Results: Roflu treatment reduced microglial senescence, ROS production, and secretion of pro-inflammatory cytokines in OGD/R-exposed BV2 cells. It also restored cell proliferation capacity and reversed OGD/R-induced cell cycle arrest. In vivo, Roflu alleviated retinal senescence, preserved retinal thickness, and protected against RGCs death in the RIR mouse model. Mechanistically, Roflu inhibited the NLRP3 inflammasome activation and suppressed DNA damage signaling pathway in microglia. Conclusions: Roflu exerts neuroprotective effects by mitigating microglial senescence and inflammation via inhibition of the NLRP3 inflammasome in RIR injury. These findings suggest that Roflu may serve as a promising therapeutic strategy for retinal diseases associated with ischemic injury by targeting microglial senescence.

Estimation of Chloride Channel Residual Function and Assessment of Targeted Drugs Efficiency in the Presence of a Complex Allele [L467F;F508del] in the CFTR Gene.

Complex alleles of the CFTR gene complicate the diagnosis of cystic fibrosis (CF), the classification of its pathogenic variants, affect the clinical picture of the disease and can affect the efficiency of targeted drugs. The total frequency of complex allele [L467F;F508del] in the Russian population of patients with CF is 0.74%, and in patients with the F508del/F508del genotype, its frequency reaches 8%. This article presents multi-faceted study of the complex allele [L467F;F508del] in a cohort of patients with genotypes [L467F;F508del]/class I (c.3532_3535dup, c.1766+2T>C, W1310X, 712-1G>T), and data for a unique patient with the genotype [L467F;F508del]/[L467F;F508del]. Using the intestinal current measurement method, it was demonstrated the absence of CFTR function for [L467F;F508del]/class I and [L467F;F508del]/[L467F;F508del] genotypes. In intestinal organoids, it was shown that [L467F;F508del] in combination with class I variants and in the homozygotes abolishes the efficacy of both two-component (ivacaftor+lumacaftor; ivacaftor+tezacaftor) and three-component (ivacaftor+tezacaftor+elexacaftor) targeted drugs. When prescribing ivacaftor+tezacaftor+elexacaftor to three patients, they did not have a clinical effect after 6-12 months.

Cardiovascular effects of Roflumilast during sepsis: Risks or benefits?

BACKGROUND: Phosphodiesterase-4 (PDE4) is responsible for terminating cyclic adenosine monophosphate (cAMP) signalling. PDE4 inhibitors, such as roflumilast (RFM), have anti-inflammatory activity and have been studied in inflammation-induced tissue damage in sepsis. However, the role of RFM on cardiovascular derangements induced by sepsis is still unknown. Thus, we aimed to evaluate the potential effects of RFM on cardiovascular collapse and multiorgan damage caused by sepsis. METHODS: Sepsis was induced by cecal ligation and puncture (CLP) in male rats. Six hours after the CLP or sham procedure, animals were randomly assigned to receive either RFM (0.3 mg/kg) or vehicle subcutaneously, and cardiovascular parameters were assessed 24 h after the surgery and organ/plasma samples were collected for further analyses. RESULTS: Sepsis induced hypotension, tachycardia, reduced renal blood flow (RBF) and hyporeactivity to vasoconstrictors both in vivo and ex vivo. RFM treatment increased systemic cAMP levels and RBF. RFM also attenuated hypoperfusion and liver damage induced by CLP. Furthermore, RFM reduced systemic nitric oxide (NO) levels in septic rats, while there were no changes in hepatic NOS-2 expression. Nevertheless, RFM exacerbated sepsis-induced hypotension and tachycardia without ameliorating vascular hyporeactivity. CONCLUSION: Our data show that PDE-4 inhibition protects septic rats from hepatic injury and improves renal perfusion. However, RFM worsened hemodynamic parameters and showed no protection against sepsis-induced cardiovascular dysfunction and mortality. Thus, despite the anti-inflammatory benefits of RFM, its application in sepsis should be approached cautiously.

Therapeutic Prospects of Abemaciclib for Patients with Endometrial Cancer.

Endometrial cancer (EC) is a common gynecologic malignancy with a rising incidence due to obesity, comorbid conditions, and related lifestyle factors. The standard of care for primary disease consists of surgical resection with/without chemotherapy ± radiotherapy for select patients. Recurrence is common in patients with advanced-stage disease and/or high-risk features, who primarily are treated with systemic therapy. The identification of novel targets in malignant EC has led to the development of wide-range inhibitors. Abemaciclib is an orally active unique cyclin-dependent kinase (CDK) inhibitor, selective for the CDK4 and CDK6 cell cycle pathways. This agent has potential anti-neoplastic activity and is indicated in combination with various therapies such as endocrine therapy, aromatase inhibitors, and hormone therapies, primarily in breast cancer (BC). Herein, we sought to summarize the biochemical/pharmacological properties of abemaciclib and its therapeutic potential in EC. While the therapeutic role(s) of abemaciclib was fairly established in a subset of patients with advanced/metastatic BC through the pivotal MONARCH trials, its attributes and clinical utility in EC are limited. Thus, based on some promising pre-clinical/translational insights and a recent phase II study, we highlight abemaciclib's properties and potential clinical usefulness in patients with EC, particularly in recurrent estrogen-receptor-positive cases.

Multimodal analyses of immune cells during bone repair identify macrophages as a therapeutic target in musculoskeletal trauma.

Musculoskeletal traumatic injuries (MTI) involve soft tissue lesions adjacent to a bone fracture leading to fibrous nonunion. The impact of MTI on the inflammatory response to fracture and on the immunomodulation of skeletal stem/progenitor cells (SSPCs) remains unknown. Here, we used single-nucleus transcriptomic analyses to describe the immune cell dynamics after bone fracture and identified distinct macrophage subsets with successive pro-inflammatory, pro-repair and anti-inflammatory profiles. Concurrently, SSPCs transition via a pro- and anti-inflammatory fibrogenic phase of differentiation prior to osteochondrogenic differentiation. In a preclinical MTI mouse model, the injury response of immune cells and SSPCs is disrupted leading to a prolonged pro-inflammatory phase and delayed resolution of inflammation. Macrophage depletion improves bone regeneration in MTI demonstrating macrophage involvement in fibrous nonunion. Finally, pharmacological inhibition of macrophages using the CSF1R inhibitor Pexidartinib ameliorates healing. These findings reveal the coordinated immune response of macrophages and skeletal stem/progenitor cells as a driver of bone healing and as a primary target for the treatment of trauma-associated fibrosis.

Anti-PD-L1 antibody ASC22 in combination with a histone deacetylase inhibitor chidamide as a "shock and kill" strategy for ART-free virological control: a phase II single-arm study.

The combination of ASC22, an anti-PD-L1 antibody potentially enhancing HIV-specific immunity and chidamide, a HIV latency reversal agent, may serve as a strategy for antiretroviral therapy-free virological control for HIV. People living with HIV, having achieved virological suppression, were enrolled to receive ASC22 and chidamide treatment in addition to their antiretroviral therapy. Participants were monitored over 24 weeks to measure changes in viral dynamics and the function of HIV-specific CD8+ T cells (NCT05129189). 15 participants completed the study. At week 8, CA HIV RNA levels showed a significant increase from baseline, and the values returned to baseline after discontinuing ASC22 and chidamide. The total HIV DNA was only transiently increased at week 4 (P = 0.014). In contrast, integrated HIV DNA did not significantly differ from baseline. Increases in the proportions of effector memory CD4+ and CD8+ T cells (TEM) were observed from baseline to week 24 (P = 0.034 and P = 0.002, respectively). The combination treatment did not succeed in enhancing the function of HIV Gag/Pol- specific CD8+ T cells. Nevertheless, at week 8, a negative correlation was identified between the proportions of HIV Gag-specific TEM cells and alterations in integrated DNA in the T cell function improved group (P = 0.042 and P = 0.034, respectively). Nine adverse events were solicited, all of which were graded 1 and resolved spontaneously. The combined treatment of ASC22 and chidamide was demonstrated to be well-tolerated and effective in activating latent HIV reservoirs. Further investigations are warranted in the context of analytic treatment interruption.

Ozenoxacin suppresses sebum production by inhibiting mTORC1 activation in differentiated hamster sebocytes.

Acne vulgaris is a complex condition involving factors that affect the pilosebaceous unit. A primary manifestation of acne pathology is the development of comedones, often linked to the overproduction of sebum resulting from 5α-dihydrotestosterone (5α-DHT) and insulin activity. Ozenoxacin is a topical quinolone that exhibits potent antibacterial activity against Cutibacterium acnes (C. acnes). It is commonly used to treat acne associated with this bacterium; however, its effect on sebum production within the sebaceous glands remains unclear. In this study, the effects of ozenoxacin on sebum production were examined using insulin- and 5α-DHT-differentiated hamster sebocytes. Ozenoxacin showed a dose-dependent inhibition of lipid droplet formation and triacylglycerol (TG) production, which is a major component of sebum. In addition, it suppressed the expression of diacylglycerol acyltransferase 1, stearoyl-CoA desaturase-1, and perilipin-1 mRNA, all important factors involved in sebum synthesis, in a dose-dependent manner. Moreover, ozenoxacin decreased phosphorylated 40S ribosomal protein S6 levels downstream of the mechanistic/mammalian target of rapamycin complex 1 (mTORC1), without altering the phosphorylation of Akt, an upstream regulator of mTORC1, in both insulin- and 5α-DHT-treated hamster sebocytes. Interestingly, nadifloxacin, but not clindamycin, exhibited a similar suppression of sebum production, albeit with lesser potency compared with ozenoxacin. Furthermore, a topical application of a 2% ozenoxacin-containing lotion to the auricle skin of hamsters did not affect the size of the sebaceous glands or epidermal thickness. Notably, it decreased the amount of TG on the skin surface. The results provide novel insights into the sebum-inhibitory properties of ozenoxacin, indicating its potential efficacy in controlling microbial growth and regulating sebum production for acne management.

Switch to phagocytic microglia by CSFR1 inhibition drives amyloid-beta clearance from glutamatergic terminals rescuing LTP in acute hippocampal slices.

Microglia, traditionally regarded as innate immune cells in the brain, drive neuroinflammation and synaptic dysfunctions in the early phases of Alzheimer disease (AD), acting upstream to Aß accumulation. Colony stimulating factor 1-receptor (CSF-1R) is predominantly expressed on microglia and its levels are significantly increased in neurodegenerative diseases, possibly contributing to the chronic inflammatory microglial response. On the other hand, CSF-1R inhibitors confer neuroprotection in preclinical models of neurodegenerative diseases. Here, we determined the effects of the CSF-1R inhibitor PLX3397 on the Aß-mediated synaptic alterations in ex vivo hippocampal slices. Electrophysiological findings show that PLX3397 rescues LTP impairment and neurotransmission changes induced by Aß. In addition, using confocal imaging experiments, we demonstrate that PLX3397 stimulates a microglial transition toward a phagocytic phenotype, which in turn promotes the clearance of Aß from glutamatergic terminals. We believe that the selective pruning of Aß-loaded synaptic terminals might contribute to the restoration of LTP and excitatory transmission alterations observed upon acute PLX3397 treatment. This result is in accordance with the mechanism proposed for CSF1R inhibitors, that is to eliminate responsive microglia and replace it with newly generated, homeostatic microglia, capable of promoting brain repair. Overall, our findings identify a connection between the rapid microglia adjustments and the early synaptic alterations observed in AD, possibly highlighting a novel disease-modifying target.

Synthesis, Computational Study, and In Vitro α-Glucosidase Inhibitory Action of Thiourea Derivatives Based on 3-Aminopyridin-2(1H)-Ones.

Reactions with allyl-, acetyl-, and phenylisothiocyanate have been studied on the basis of 3-amino-4,6-dimethylpyridine-2(1H)-one, 3-amino-4-phenylpyridine-2-one, and 3-amino-4-(thiophene-2-yl)pyridine-2(1H)-one (benzoyl-)isothiocyanates, and the corresponding thioureide derivatives 8-11a-c were obtained. Twelve thiourea derivatives were obtained and studied for their anti-diabetic activity against the enzyme α-glucosidase in comparison with the standard drug acarbose. The comparison drug acarbose inhibits the activity of α-glucosidase at a concentration of 15 mM by 46.1% (IC50 for acarbose is 11.96 mM). According to the results of the conducted studies, it was shown that alkyl and phenyl thiourea derivatives 8,9a-c, in contrast to their acetyl-(benzoyl) derivatives and 10,11a-c, show high antidiabetic activity. Thus, 1-(4,6-dimethyl-2-oxo-1,2-dihydropyridin-3-yl)-3-phenylthiourea 9a has the highest inhibitory activity against the enzyme α-glucosidase, exceeding the activity of the comparison drug acarbose, which inhibits the activity of α-glucosidase by 56.6% at a concentration of 15 mm (IC50 = 9,77 mM). 1-(6-methyl-2-oxo 4-(thiophen-2-yl)-1,2-dihydropyridin-3-yl)-3-phenylthiourea 9c has inhibitory activity against the enzyme α-glucosidase, comparable to the comparison drug acarbose, inhibiting the activity of α-glucosidase at a concentration of 15 mm per 41.2% (IC50 = 12,94 mM). Compounds 8a, 8b, and 9b showed inhibitory activity against the enzyme α-glucosidase, with a lower activity compared to acarbose, inhibiting the activity of α-glucosidase at a concentration of 15 mM by 23.3%, 26.9%, and 35.2%, respectively. The IC50 against α-glucosidase for compounds 8a, 8b, and 9b was found to be 16.64 mM, 19.79 mM, and 21.79 mM, respectively. The other compounds 8c, 10a, 10b, 10c, 11a, 11b, and 11c did not show inhibitory activity against α-glucosidase. Thus, the newly synthesized derivatives of thiourea based on 3-aminopyridine-2(1H)-ones are promising candidates for the further modification and study of their potential anti-diabetic activity. These positive bioanalytical results will stimulate further in-depth studies, including in vivo models.

CDK4/6 Inhibitors Impede Chemoresistance and Inhibit Tumor Growth of Small Cell Lung Cancer.

Small cell lung cancer (SCLC) is characterized by rapid development of chemoresistance and poor outcomes. Cyclin-dependent kinase 4/6 inhibitors (CDK4/6is) are widely used in breast cancer and other cancer types. However, the molecular mechanisms of CDK4/6 in SCLC chemoresistance remain poorly understood. Here, Rb1flox/flox, Trp53flox/flox, Ptenflox/flox (RTP) and Rb1flox/flox, Trp53flox/flox, MycLSL/LSL (RPM) spontaneous SCLC mouse models, SCLC cell line-derived xenograft (CDX) models, and SCLC patient-derived xenograft (PDX) models are established to reveal the potential effects of CDK4/6is on SCLC chemoresistance. In this study, it is found that CDK4/6is palbociclib (PD) or ribociclib (LEE) combined with chemotherapeutic drugs significantly inhibit SCLC tumor growth. Mechanistically, CDK4/6is do not function through the classic Retionblastoma1 (RB) dependent axis in SCLC. CDK4/6is induce impair autophagy through the AMBRA1-lysosome signaling pathway. The upregulated AMBRA1 protein expression leads to CDK6 degradation via autophagy,  and the following TFEB and TFE3 nuclear translocation inhibition leading to the lysosome-related genes levels downregulation. Moreover, it is found that the expression of CDK6 is higher in SCLC tumors than in normal tissue and it is associated with the survival and prognosis of SCLC patients. Finally, these findings demonstrate that combining CDK4/6is with chemotherapy treatment may serve as a potential therapeutic option for SCLC patients.

Synthesis and Biological Evaluation of Pyrazole-Pyrimidones as a New Class of Correctors of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR).

Cystic fibrosis (CF) is caused by the functional expression defect of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Despite the recent success in CFTR modulator development, the available correctors only partially restore the F508del-CFTR channel function, and several rare CF mutations show resistance to available drugs. We previously identified compound 4172 that synergistically rescued the F508del-CFTR folding defect in combination with the existing corrector drugs VX-809 and VX-661. Here, novel CFTR correctors were designed by applying a classical medicinal chemistry approach on the 4172 scaffold. Molecular docking and three-dimensional quantitative structure-activity relationship (3D-QSAR) studies were conducted to propose a plausible binding site and design more potent and effective analogs. We identified three optimized compounds, which, in combination with VX-809 and the investigational corrector 3151, increased the plasma membrane density and function of F508del-CFTR and other rare CFTR mutants resistant to the currently approved therapies.

Strategy to Improve the Oral Pharmacokinetics of Cyclin-Dependent Kinase 4/6 Inhibitors: Enhancing Permeability and CYP450 Inhibition by a Natural Bioenhancer.

Palbociclib and ribociclib an orally bioavailable, potent cyclin-dependent kinase 4/6 inhibitors, with low oral bioavailability due to substrate specificity towards CYP3A and P-glycoprotein. Thus, current research aims to examine the effect of a bioenhancer (naringin), on oral pharmacokinetics of palbociclib and ribociclib. Naringin's affinity for CYP3A4 and P-glycoprotein was studied using molecular docking; its impact on palbociclib/ribociclib CYP3A metabolism and P-glycoprotein-mediated efflux was examined using in vitro preclinical models; and its oral pharmacokinetics in rats were assessed following oral administration of palbociclib/ribociclib in presence of naringin (50 and 100 mg/kg). Naringin binds optimally to both proteins with the highest net binding energy of - 1477.23 and - 1607.47 kcal/mol, respectively. The microsomal intrinsic clearance of palbociclib and ribociclib was noticeably reduced by naringin (5-100 µM), by 3.0 and 2.46-folds, respectively. Similarly, naringin had considerable impact on the intestinal transport and efflux of both drugs. The pre-treatment with 100 mg/kg naringin increased significantly (p < 0.05) the oral exposure of palbociclib (2.0-fold) and ribociclib (1.95-fold). Naringin's concurrent administration of palbociclib and ribociclib increased their oral bioavailability due to its dual inhibitory effect on CYP3A4 and P-glycoprotein; thus, concurrent naringin administration may represent an innovative strategy for enhancing bioavailability of cyclin-dependent kinase inhibitors.

Aminopyridines in the development of drug candidates against protozoan neglected tropical diseases.

Neglected tropical diseases (NTDs) pose a major threat in tropical zones for impoverished populations. Difficulty of access, adverse effects or low efficacy limit the use of current therapeutic options. Therefore, development of new drugs against NTDs is a necessity. Compounds containing an aminopyridine (AP) moiety are of great interest for the design of new anti-NTD drugs due to their intrinsic properties compared with their closest chemical structures. Currently, over 40 compounds with an AP moiety are on the market, but none is used against NTDs despite active research on APs. The aim of this review is to present the medicinal chemistry work carried out with these scaffolds, against protozoan NTDs: Trypanosoma cruzi, Trypanosoma brucei or Leishmania spp.

[Box: see text].

The effect of ribociclib on the expression levels of miR-141 and CDK4/6-USP51 signaling pathway genes in MCF-7 and MDA-MB-231 cells.

INTRODUCTION: Patients with breast cancer, especially triple-negative breast cancer, have a poor prognosis. There is still no effective treatment for this disease. Due to resistance to traditional treatments such as chemotherapy and radiation therapy, there is a need to discover novel treatment strategies to treat this disease. Ribociclib is a selective CDK4/6 inhibitor. Approximately 20% of patients with HR+ breast cancer developed primary resistance to CDK4/6 inhibitors, and more than 30% experienced secondary resistance. Since most patients experience resistance during CDK4/6 inhibitor treatment, managing this disease is becoming more challenging. Many malignant tumors abnormally express microRNA (miR)-141, which participates in several cellular processes, including drug resistance, proliferation, epithelial-mesenchymal transition, migration, and invasion. MATERIALS AND METHODS: In the present study, we cultured MDA-MB-231 and MCF-7 cells in DMEM-F12 medium. By performing MTT assay we determined the cytotoxic effects of ribociclib on breast cancer cells, as well as determining the IC50 of it. Then, we treated the cells with ribociclib at two time points: 24 h and 72 h. After that, RNA was isolated and reverse transcribed to cDNA. Finally, we performed qRT‒PCR to evaluate how ribociclib affects the expression level of desired genes. RESULTS AND CONCLUSION: We found that ribociclib can inhibit cell growth in a dose- and time-dependent manner. We examined the mRNA expression of 4 genes. After ribociclib treatment, the mRNA expression of CDK6 and MYH10 decreased (p < 0.01, p < 0.05). The mRNA expression of CDON increased (p<0.05), but no significant changes were observed in ZEB1 mRNA expression. Furthermore, the qRT‒PCR results for miR-141 showed that the expression of miR-141 increased (p<0.01) after 72 h of treatment with ribociclib.

BCL6 confers resistance to HDAC inhibitors in DLBCL.

Diffuse large B-cell lymphoma (DLBCL) is an aggressive non-Hodgkin lymphoma with limited response to chemotherapy. Histone acetylation is reduced in DLBCL. Chidamide, a histone deacetylase inhibitor, shows promise in lymphomas but needs further investigation for DLBCL. Our study indicated that chidamide effectively suppresses DLBCL both in vitro and in vivo. High-throughput RNA sequencing analysis provided comprehensive evidence that chidamide markedly influences crucial signaling pathways in DLBCL, including the MAPK, MYC and p53 pathway. Additionally, we observed substantial variability in the sensitivity of DLBCL cells to chidamide, and identified that elevated expression of BCL6 might confer resistance to chidamide in DLBCL. Moreover, our investigations revealed that BCL6 inhibited chidamide-induced histone acetylation by recruiting histone deacetylase (HDACs), leading to drug resistance in DLBCL cells. Furthermore, we found that lenalidomide targeted BCL6 degradation through the ubiquitination pathway and restore the sensitivity of drug-resistant DLBCL to chidamide. Collectively, these findings provided valuable insights into the global impact of chidamide on DLBCL and highlight the potential of targeting HDACs as a therapeutic strategy for DLBCL. Identifying BCL6 as a biomarker for predicting the response to chidamide and the combination therapy with BCL6 inhibition has the potential to lead to more personalized and effective treatments for DLBCL patients.

Discovery of Novel 2-Aminopyridine-Based and 2-Aminopyrimidine-Based Derivatives as Potent CDK/HDAC Dual Inhibitors for the Treatment of Refractory Solid Tumors and Hematological Malignancies.

Co-inhibition of histone deacetylase (HDAC) and cyclin-dependent kinase (CDK) synergizes to produce enhanced antitumor effects and potentially overcomes the drug resistance. In this work, we discovered a series of novel CDK9/HDACs dual inhibitors. Among them, compound 8e was identified to show potent CDK9 and HDAC1 inhibitory activities, with IC50 values at 88.4 and 168.9 nM, respectively, and exhibited antiproliferative capacities against hematological and solid tumor cells. Meanwhile, 8e showed high selectivity for CDK9 and HDAC1, remarkably induced MV-4-11 cell apoptosis and S cell cycle arrests. Furthermore, 8e possessed a significant antitumor potency with a T/C value of 29.98% in the MV-4-11 xenograft model. Interestingly, a potent FLT3/HDAC dual inhibitor 9e was also identified (FLT3/HDAC1/3 IC50 = 30.4/52.4/14.7 nM) and found to possess powerful apoptosis induction ability in MV-4-11 cell and potent antiproliferative capacities against FLT3 mutant-transformed BaF3 cells. Overall, our work provided valuable lead compounds for dual inhibitors with potent anticancer activity.

The Effect of Concomitant Administration of Proton Pump Inhibitors on the Pharmacokinetics of CDK4/6 Inhibitors in Rats: Implications for the Evaluation of Hepatic and Transporter-Mediated Drug-Drug Interactions.

BACKGROUND AND OBJECTIVES: Numerous clinical concerns have been expressed regarding the potential worsening of cyclin-dependent kinase 4/6 inhibitor effects in breast cancer patients because of co-administration of proton pump inhibitors. Hence, this study evaluated the effects of proton pump inhibitors on the pharmacokinetics of palbociclib and ribociclib in terms of  cytochrome P450 (CYP) 3A4 and P-glycoprotein involvement. METHODS: The effects of omeprazole and rabeprazole on drug metabolism and efflux of these drugs were investigated using molecular docking, metabolic stability assay in rat liver microsomes, human recombinant CYP3A4 (rCYP3A4) enzymes, and Caco-2 cell monolayers, and in vivo pharmacokinetics with omeprazole and rabeprazole in (5 and 10 mg/kg) 30 min and 7 days before orally dosing palbociclib and ribociclib (10 mg/kg). RESULTS: Omeprazole and rabeprazole inhibited CYP3A4 enzyme activity in rCYP3A4 baculosomes with a 50-60% inhibition at 30 µM. Additionally, both omeprazole and rabeprazole (10 µm) significantly reduced the P-glycoprotein-mediated drug efflux of palbociclib and ribociclib. The 7-day pretreatment of omeprazole at a dose of 10 mg/kg resulted in 24% and 26% reductions in palbociclib's mean maximum plasma concentration) Cmax and area under the plasma concentration-time curve (AUC0-24 h), respectively. Palbociclib's pharmacokinetics were not significantly altered by the pretreatment with rabeprazole; however, ribociclib pharmacokinetics exhibited an 83.94% increase in AUC0-24 h. CONCLUSION: The findings indicate that long-term treatment with therapeutic doses of both omeprazole and rabeprazole can alter the pharmacokinetics of palbociclib and ribociclib. The co-administration of rabeprazole may alter the pharmacokinetics of palbociclib and ribociclib via CYP enzyme and P-glycoprotein inhibition.

[Advances in basic and clinical research of flumatinib].

Chronic myelogenous leukemia (CML) is a hematological malignancy originating from the pluripotent hematopoietic stem cells. Imatinib is the first generation of small molecule tyrosine kinase inhibitors (TKI) that revolutionized the treatment of CML. Flumatinib, as a novel oral TKI that independently developed in China, which can be used as a preferred treatment for CML. Basic researches suggested that the inhibitory effect of flumatinib on CML cell lines is stronger than imatinib. Flumatinib demonstrated that it has better efficacy than imatinib on CML in clinical trials and in real world studies. Flumatinib also showed a higher potency against CML with specific mutations, Ph(+) acute lymphoblastic leukemia and some solid tumors. The adverse events are manageable and tolerable.

Microglia mediate the increase in slow-wave sleep associated with high ambient temperature.

An increase in ambient temperature leads to an increase in sleep. However, the mechanisms behind this phenomenon remain unknown. This study aimed to investigate the role of microglia in the increase of sleep caused by high ambient temperature. We confirmed that at 35 °C, slow-wave sleep was significantly increased relative to those observed at 25 °C. Notably, this effect was abolished upon treatment with PLX3397, a CSF1R inhibitor that can deplete microglia, while sleep amount at 25 °C was unaffected. These observations suggest that microglia play a pivotal role in modulating the homeostatic regulation of sleep in response to the fluctuations in ambient temperature.

Pexidartinib and Immune Checkpoint Inhibitors Combine to Activate Tumor Immunity in a Murine Colorectal Cancer Model by Depleting M2 Macrophages Differentiated by Cancer-Associated Fibroblasts.

Tumor-associated macrophages (TAMs) and cancer-associated fibroblasts (CAFs) are known to play supportive roles in tumor development and progression, but their interactions in colorectal cancer (CRC) remain unclear. Here, we investigated the effects of colon-cancer-derived CAFs on TAM differentiation, migration, and tumor immunity, both in vitro and in vivo. When co-cultured with monocytes, CAFs attracted monocytes and induced their differentiation into M2 macrophages. Immunohistology of surgically resected human CRC specimens and orthotopically transplanted mouse tumors revealed a correlation between numbers of CAFs and numbers of M2 macrophages. In a mouse model of CRC orthotopic transplantation, treatment with an inhibitor of the colony-stimulating factor-1 receptor (PLX3397) depleted M2 macrophages and increased CD8-positive T cells infiltrating the tumor nest. While this treatment had a minor effect on tumor growth, combining PLX3397 with anti-PD-1 antibody significantly reduced tumor growth. RNA-seq following combination therapy showed activation of tumor immunity. In summary, CAFs are involved in the induction and mobilization of M2 macrophage differentiation in the CRC tumor immune microenvironment, and the combination of cancer immunotherapy and PLX3397 may represent a novel therapeutic option for CRC.