Eed-dependent histone modification orchestrates the iNKT cell developmental program alleviating liver injury.

Polycomb repressive complex 2 (PRC2) is an evolutionarily conserved epigenetic modifier responsible for tri-methylation of lysine 27 on histone H3 (H3K27me3). Previous studies have linked PRC2 to invariant natural killer T (iNKT) cell development, but its physiological and precise role remained unclear. To address this, we conditionally deleted Eed, a core subunit of PRC2, in mouse T cells. The results showed that Eed-deficient mice exhibited a severe reduction in iNKT cell numbers, particularly NKT1 and NKT17 cells, while conventional T cells and NKT2 cells remained intact. Deletion of Eed disrupted iNKT cell differentiation, leading to increased cell death, which was accompanied by a severe reduction in H3K27me3 levels and abnormal expression of Zbtb16, Cdkn2a, and Cdkn1a. Interestingly, Eed-deficient mice were highly susceptible to acetaminophen-induced liver injury and inflammation in an iNKT cell-dependent manner, highlighting the critical role of Eed-mediated H3K27me3 marks in liver-resident iNKT cells. These findings provide further insight into the epigenetic orchestration of iNKT cell-specific transcriptional programs.

The miR-221/222 cluster regulates hematopoietic stem cell quiescence and multipotency by suppressing both Fos/AP-1/IEG pathway activation and stress-like differentiation to granulocytes.

Throughout life, hematopoietic stem cells (HSCs), residing in bone marrow (BM), continuously regenerate erythroid/megakaryocytic, myeloid, and lymphoid cell lineages. This steady-state hematopoiesis from HSC and multipotent progenitors (MPPs) in BM can be perturbed by stress. The molecular controls of how stress can impact hematopoietic output remain poorly understood. MicroRNAs (miRNAs) as posttranscriptional regulators of gene expression have been found to control various functions in hematopoiesis. We find that the miR-221/222 cluster, which is expressed in HSC and in MPPs differentiating from them, perturbs steady-state hematopoiesis in ways comparable to stress. We compare pool sizes and single-cell transcriptomes of HSC and MPPs in unperturbed or stress-perturbed, miR-221/222-proficient or miR-221/222-deficient states. MiR-221/222 deficiency in hematopoietic cells was induced in C57BL/6J mice by conditional vav-cre-mediated deletion of the floxed miR-221/222 gene cluster. Social stress as well as miR-221/222 deficiency, alone or in combination, reduced HSC pools 3-fold and increased MPPs 1.5-fold. It also enhanced granulopoisis in the spleen. Furthermore, combined stress and miR-221/222 deficiency increased the erythroid/myeloid/granulocytic precursor pools in BM. Differential expression analyses of single-cell RNAseq transcriptomes of unperturbed and stressed, proficient HSC and MPPs detected more than 80 genes, selectively up-regulated in stressed cells, among them immediate early genes (IEGs). The same differential single-cell transcriptome analyses of unperturbed, miR-221/222-proficient with deficient HSC and MPPs identified Fos, Jun, JunB, Klf6, Nr4a1, Ier2, Zfp36-all IEGs-as well as CD74 and Ly6a as potential miRNA targets. Three of them, Klf6, Nr4a1, and Zfp36, have previously been found to influence myelogranulopoiesis. Together with increased levels of Jun, Fos forms increased amounts of the heterodimeric activator protein-1 (AP-1), which is known to control the expression of the selectively up-regulated expression of the IEGs. The comparisons of single-cell mRNA-deep sequencing analyses of socially stressed with miR-221/222-deficient HSC identify 5 of the 7 Fos/AP-1-controlled IEGs, Ier2, Jun, Junb, Klf6, and Zfp36, as common activators of HSC from quiescence. Combined with stress, miR-221/222 deficiency enhanced the Fos/AP-1/IEG pathway, extended it to MPPs, and increased the number of granulocyte precursors in BM, inducing selective up-regulation of genes encoding heat shock proteins Hspa5 and Hspa8, tubulin-cytoskeleton-organizing proteins Tuba1b, Tubb 4b and 5, and chromatin remodeling proteins H3f3b, H2afx, H2afz, and Hmgb2. Up-regulated in HSC, MPP1, and/or MPP2, they appear as potential regulators of stress-induced, miR-221/222-dependent increased granulocyte differentiation. Finally, stress by serial transplantations of miR-221/222-deficient HSC selectively exhausted their lymphoid differentiation capacities, while retaining their ability to home to BM and to differentiate to granulocytes. Thus, miR-221/222 maintains HSC quiescence and multipotency by suppressing Fos/AP-1/IEG-mediated activation and by suppressing enhanced stress-like differentiation to granulocytes. Since miR-221/222 is also expressed in human HSC, controlled induction of miR-221/222 in HSC should improve BM transplantations.

Structural basis of spike RBM-specific human antibodies counteracting broad SARS-CoV-2 variants.

The decrease of antibody efficacy to mutated SARS-CoV-2 spike RBD explains the breakthrough infections and reinfections by Omicron variants. Here, we analyzed broadly neutralizing antibodies isolated from long-term hospitalized convalescent patients of early SARS-CoV-2 strains. One of the antibodies named NCV2SG48 is highly potent to broad SARS-CoV-2 variants including Omicron BA.1, BA.2, and BA.4/5. To reveal the mode of action, we determined the sequence and crystal structure of the Fab fragment of NCV2SG48 in a complex with spike RBD from the original, Delta, and Omicron BA.1. NCV2SG48 is from a minor VH but the multiple somatic hypermutations contribute to a markedly extended binding interface and hydrogen bonds to interact with conserved residues at the core receptor-binding motif of RBD, which efficiently neutralizes a broad spectrum of variants. Thus, eliciting the RBD-specific B cells to the longitudinal germinal center reaction confers potent immunity to broad SARS-CoV-2 variants emerging one after another.

Optimal Administration of Glycyrrhizin Avoids Pharmacokinetic Interactions With High-dose Methotrexate and Exerts a Hepatoprotective Effect.

BACKGROUND/AIM: Glycyrrhizin (GZ) is widely used to treat high-dose methotrexate (MTX)-induced liver dysfunction. However, in a previous in vivo study, we showed that simultaneous administration of both drugs increased the plasma concentration of MTX and exacerbated hepatic injuries. In this study, we investigated the optimal dosing interval in rats to avoid the interaction between high-dose MTX and GZ and to demonstrate the inherent hepatoprotective effect of GZ. MATERIALS AND METHODS: Male Wistar rats were treated with high-dose MTX (2,000 mg/kg) alone, with concomitant administration of 100 mg/kg GZ or GZ administered 3, 6, and 24 h before MTX administration. Plasma concentrations of MTX, alanine aminotransferase, aspartate aminotransferase, and total bilirubin were measured. RESULTS: The plasma concentration and half-life of methotrexate were significantly increased after concomitant administration of GZ, or when GZ was administered 3 h before MTX administration, compared with MTX alone, increasing hepatic enzyme levels. However, when GZ was administered 6 and 24 h before MTX administration, the levels were not significantly different from those of MTX alone and showed a tendency to decrease MTX-induced liver injury. These results suggest that the pharmacokinetic interaction between GZ and MTX could be avoided and the hepatoprotective effect of GZ could be achieved by an optimal dosing regimen, using the half-life of GZ as an indicator. CONCLUSION: When using high-dose MTX in combination with GZ, the administration intervals should be considered to avoid unwanted interactions and to achieve the GZ hepatoprotective effect.

Vaccination with the Omicron spike RBD boosts broadly neutralizing antibody levels and confers sustained protection even after acquiring immunity to the original antigen.

The immune evasion of SARS-CoV-2 Omicron variants caused by multiple amino acid replacements in the receptor-binding domain (RBD) of the spike protein wanes the effectiveness of antibodies elicited by current SARS-CoV-2 booster vaccination. The vaccines that target Omicron strains have been recently developed, however, there has been a concern yet to be addressed regarding the negative aspect of the immune response known as original antigenic sin. Here, we demonstrate that the breadth of neutralizing antibodies against SARS-CoV-2 variants is barely elicited by immunizing monovalent viral antigens via vaccination or natural infection in mice and human subjects. However, vaccination of Omicron BA.1 RBD to pre-immunized mice with the original RBD conferred sustained neutralizing activity to BA.1 and BA.2 not only original pseudoviruses. The acquisition of neutralizing antibody breadth was further confirmed in vaccinated-then-Omicron convalescent human sera in which neutralizing activity against BA.1 and BA.2 pseudoviruses was highly induced. Thus, our data suggest that Omicron-specific vaccines or the infection with Omicron viruses can boost potent neutralizing antibodies to the Omicron variants even in the host pre-vaccinated with the original antigen.

Paliperidone-Induced Acute Hyperglycemia Is Caused by Adrenaline Secretion via the Activation of Hypothalamic AMP-Activated Protein Kinase.

Although paliperidone-related hyperglycemia has been extensively examined, the underlying mechanisms have not yet been elucidated. We investigated the effects of a single intravenous injection of paliperidone (0.2, 0.4, or 0.6 mg/kg) on serum concentrations of glucose and other endogenous metabolites in rats. We also examined the effects of a single intravenous injection of paliperidone (0.4 mg/kg) on AMP-activated protein kinase (AMPK) activity in the hypothalamus and liver. To clarify the relationship between AMPK activity and adrenaline secretion, the effects of berberine, which inhibits hypothalamic AMPK, on paliperidone-induced hyperglycemia were assessed. Significant increases were observed in serum glucose, adrenaline, and insulin concentrations following intravenous injections of paliperidone at doses of 0.4 and 0.6 mg/kg. A propranolol pretreatment attenuated paliperidone-induced increases in serum concentrations of glucose, but not adrenaline. Significant increases were also noted in phosphorylated AMPK concentrations in the hypothalamus following the administration of paliperidone at a dose of 0.4 mg/kg. A berberine pretreatment attenuated paliperidone-induced increases in blood concentrations of glucose, adrenaline, and insulin and phosphorylated AMPK concentrations in the hypothalamus. Collectively, the present results demonstrated that an acute treatment with paliperidone induced hyperglycemia, which was associated with the effects of hypothalamic AMPK activation on the secretion of adrenaline.

Concomitant Cytotoxic Effector Differentiation of CD4+ and CD8+ T Cells in Response to EBV-Infected B Cells.

Most people infected by EBV acquire specific immunity, which then controls latent infection throughout their life. Immune surveillance of EBV-infected cells by cytotoxic CD4+ T cells has been recognized; however, the molecular mechanism of generating cytotoxic effector T cells of the CD4+ subset remains poorly understood. Here we compared phenotypic features and the transcriptome of EBV-specific effector-memory CD4+ T cells and CD8+ T cells in mice and found that both T cell types show cytotoxicity and, to our surprise, widely similar gene expression patterns relating to cytotoxicity. Similar to cytotoxic CD8+ T cells, EBV-specific cytotoxic CD4+ T cells from human peripheral blood expressed T-bet, Granzyme B, and Perforin and upregulated the degranulation marker, CD107a, immediately after restimulation. Furthermore, T-bet expression in cytotoxic CD4+ T cells was highly correlated with Granzyme B and Perforin expression at the protein level. Thus, differentiation of EBV-specific cytotoxic CD4+ T cells is possibly controlled by mechanisms shared by cytotoxic CD8+ T cells. T-bet-mediated transcriptional regulation may explain the similarity of cytotoxic effector differentiation between CD4+ T cells and CD8+ T cells, implicating that this differentiation pathway may be directed by environmental input rather than T cell subset.

Relationship Between Leukotriene Receptor Antagonists on Cancer Development in Patients With Bronchial Asthma: A Retrospective Analysis.

BACKGROUND/AIM: An association between leukotriene receptor antagonists (LTRA) and cancer has been previously reported, but the relationship between LTRA use and cancer prevention remains controversial. This study aimed to clarify the cancer-preventive effect of LTRA in Japanese patients with bronchial asthma. PATIENTS AND METHODS: We obtained information from a large populationbased medical information database to analyze data on patients who were newly diagnosed with bronchial asthma between 2006 and 2015. Eligible participants were patients who were prescribed an LTRA for at least 30 days (LTRA users) and those who were not using LTRA (LTRA non-users) during the objective period. LTRA users and LTRA non-users were matched 1:1 using propensity scores. RESULTS: The 1:1 propensity score matching of LTRA users and LTRA nonusers facilitated the inclusion of 3,744 participants each, in these two subgroups. The results of the Cox proportional hazards model after adjustment for covariates showed no significant difference in the cancer risk between LTRA users and non-users [adjusted hazard ratio (HR)=0.83, 95% confidence interval (CI)=0.59-1.16]. The subgroup analysis showed no significant difference in the cancer risk between the LTRA low-cumulative dose group and LTRA non-users, or between the LTRA medium-cumulative dose group and LTRA non-users. In contrast, the LTRA high-cumulative dose group had a significantly lower risk of developing cancer compared with LTRA non-users (adjusted HR=0.57, 95% CI=0.33-0.98). CONCLUSION: LTRA use may prevent cancer in patients with bronchial asthma.

VSIG4/CRIg directly regulates early CD8+ T cell activation through its counter-receptor in a narrow window.

T-cell responses are fine-tuned by positive and negative co-signal molecules expressed on immune cells and adjacent tissues. VSIG4 is a newly identified member of the B7 family of ligands, which negatively regulates innate inflammatory and CD4+ T cell-mediated responses. However, little is known about the direct effects of VSIG4, which are exerted through an unidentified counter-receptor on CD8+ T cells. We investigated the binding of the VSIG4-Ig fusion protein during CD8+ T cell activation, and the functional involvement of VSIG4 pathway, using VSIG4-Ig and VSIG4-transfectants. VSIG4-Ig binding to CD8+ T cells was temporally observed in the CD44high phenotype during initial activation. VSIG4-Ig binding was observed earlier than the induction of PD-1, LAG3, and TIM-3, which are immune checkpoint receptors for exhausted CD8+ T cells. Immobilized VSIG4-Ig inhibited anti-CD3/CD28 mAb-induced CD8+ T cell activation, as indicated by proliferation and IFN-γ production, similar to the downregulation of T-bet and Eomesodermin transcription factors. VSIG4 on FcγR+ P815 or specific antigen-presenting E.G7 cells inhibited the generation of effector CD8+ T cells, as indicated by proliferation, IFN-γ and TNF-α expression, and granule degradation, compared to parental cells. However, the window for the regulatory function of VSIG4 was narrow and dependent on the strength of TCR (and CD28)-mediated signals. Our results suggested that VSIG4 directly delivers co-inhibitory signals via an as-yet unidentified counter-receptor on activated CD8+ T cells. VSIG4-mediated CD8+ T cell tolerance might contribute to the steady-state maintenance of homeostasis.

Risk Factors for Hepatic Toxicity of High-dose Methotrexate in Patients With Osteosarcoma.

BACKGROUND/AIM: High-dose methotrexate (HD-MTX) is widely used to treat osteosarcoma. However, some patients develop hepatic toxicity, leading to dose modification and delays in the scheduled chemotherapy. The present study aimed to identify the risk factors of hepatotoxicity in patients with osteosarcoma. PATIENTS AND METHODS: We conducted a retrospective study of patients with osteosarcoma treated with HD-MTX between January 2014 and June 2020 at the National Cancer Center Hospital, Japan. The risk factors for MTX-induced hepatotoxicity (≥grade 3) were identified using multivariate logistic regression analysis. RESULTS: The final analysis included 88 courses of 36 patients. Hepatotoxicity occurred in 51 (58.0%) of the 88 courses. Female sex, MTX dose (>10.2 g/m2), and serum calcium concentration (>9.3 mg/dl) were identified as risk factors for HD-MTX-induced hepatotoxicity. CONCLUSION: Identifying the risk factors of HD-MTX-induced hepatotoxicity may contribute to improvements in the safety and management of HD-MTX therapy.

The antiplatelet effect of mirtazapine is mediated by co-blocking 5-HT2A and α2-adrenergic receptors on platelets: An in vitro human plasma-based study.

Mirtazapine (MTZ) is a noradrenergic and specific serotonergic antidepressant that has been associated with an increased risk of bleeding. However, there is insufficient evidence confirming this association. We hypothesised that 5-HT2A and α2 receptor-mediated inhibitory effects of MTZ on platelets suppress platelet aggregation and increase the risk of bleeding. In this study, we examined the antiplatelet effect of MTZ on human platelets to test our hypothesis. Blood samples for platelet aggregation tests were obtained from 14 healthy volunteers. The antiplatelet effect of MTZ was evaluated using light transmission aggregometry. MTZ significantly suppressed platelet aggregation mediated both by the synergistic interaction of serotonin (5-HT) and adrenaline and the synergistic interaction of ADP and 5-HT or adrenaline. In conclusion, MTZ exerts its antiplatelet effects by co-blocking the 5-HT2A and α2-adrenergic receptors on platelets and also suppresses platelet aggregation induced by ADP and 5-HT or adrenaline. Therefore, when MTZ is used, especially for patients with a high risk of bleeding, the significance of its use must be considered carefully. In addition, the platelet aggregation pattern by adrenaline + 5-HT, ADP + adrenaline, and ADP + 5-HT was similar between humans and mice; however, this study did not directly compare the effects of MTZ on human and murine platelets. Therefore, under the conditions for inducing platelet aggregation using adrenaline + 5-HT, ADP + adrenaline, and ADP + 5-HT, mouse platelets can be used in the evaluation of the efficacy of antiplatelet drugs in humans.

Risk Factors Associated With Unplanned Acute Care in Outpatient Chemotherapy With Oral Anticancer Drugs as Monotherapy or Combination Therapy With Injectable Anticancer Drugs.

BACKGROUND/AIM: Recently, the number of patients with cancer receiving outpatient chemotherapy using oral anticancer drugs has increased, but the currently available outpatient cancer chemotherapy is not safer than that available before. The present study aimed to identify risk factors associated with unplanned acute care (UAC) requiring outpatient chemotherapy-related consultation and hospitalisation. PATIENTS AND METHODS: We conducted a case- control study among 1,674 patients who received oral anticancer drug treatment either alone or in combination with injectable anticancer drugs at National Cancer Center Hospital East, Japan, between December 1, 2014, and November 30, 2015. RESULTS: Body mass index (BMI) was identified as a risk factor for UAC during chemotherapy. Patients with a BMI of <18.5 kg/m2, classified as underweight according to the World Health Organization classification of nutritional status, had a significantly higher risk of UAC. CONCLUSION: A low BMI immediately before the occurrence of chemotherapy-related UAC is a risk factor for adverse effects; therefore, underweight patients need more careful monitoring and supportive care.

Leukotriene Receptor Antagonist Use and Dementia Risk in Patients With Asthma: A Retrospective Cohort Study.

BACKGROUND/AIM: Recent experimental studies have reported that leukotriene receptor antagonists (LTRAs) might protect against dementia. However, few clinical studies have examined this in humans. This study assessed whether the use of LTRAs can prevent the onset of dementia in humans. PATIENTS AND METHODS: A large population-based retrospective cohort study was conducted using a health insurance claims database in Japan, which included patients newly diagnosed with bronchial asthma between 2006 and 2015. Each of these patients that was LTRA user was matched with a randomly selected LTRA non-user according to age, sex, and bronchial asthma diagnostic year. RESULTS: There were 10,471 patients in both the LTRA user and the LTRA non-user group. Using Cox proportional hazards models, a significant reduction in the risk of developing dementia was observed in the LTRA user group compared to the non-user group (adjusted hazard ratio=0.42, 95% confidence interval=0.20-0.87, p=0.019). CONCLUSION: Our data suggest that the use of LTRAs may prevent the onset of dementia in asthmatic patients.

Comparison of the Safety and Effectiveness of Four Direct Oral Anticoagulants in Japanese Patients with Nonvalvular Atrial Fibrillation Using Real-World Data.

Direct oral anticoagulants (DOACs) are widely used for the prevention of ischemic stroke and systemic embolism in patients with nonvalvular atrial fibrillation (NVAF). However, the differences in safety and effectiveness among four DOACs, dabigatran, rivaroxaban, apixaban, and edoxaban, in Japanese patients have not been clarified. Therefore, we conducted a retrospective cohort study to directly compare the safety and effectiveness among the four DOACs using the Japan Medical Data Center (JMDC) claims database. We identified 3823 patients with NVAF who started receiving a DOAC between March 2011 and June 2017. The safety outcome was major bleeding (a composite outcome of intracranial, gastrointestinal, respiratory, or renal/urinary tract bleeding) and the effectiveness outcome was the composite of ischemic stroke including transient ischemic attack (TIA) or systemic embolism. We constructed a Cox proportional hazard model to calculate the hazard ratio (HR) for all four DOAC combinations. The risk of major bleeding was significantly lower in the dabigatran group than in the apixaban group (HR, 0.55; 95% confidence interval (CI), 0.31-0.93; p = 0.03). In contrast, there was no significant difference in the risk of major bleeding among the other DOACs. In the composite risk of ischemic stroke including TIA or systemic embolism, there was no significant difference among the four DOACs. This study suggested that in the current use of DOACs in Japanese patients with NVAF, dabigatran had a significantly lower risk of major bleeding than apixaban, but there was no significant difference in effectiveness among the four DOACs.

Concomitant Use of High-dose Methotrexate and Glycyrrhizin Affects Pharmacokinetics of Methotrexate, Resulting in Hepatic Toxicity.

BACKGROUND/AIM: High-dose methotrexate is a therapy for acute leukemia, malignant lymphoma, and osteosarcoma. Glycyrrhizin has been used to treat hepatic dysfunction caused by high-dose methotrexate. However, few studies have investigated the interaction between glycyrrhizin and high-dose methotrexate. MATERIALS AND METHODS: Male Wistar rats were treated with high-dose methotrexate (500 or 1,000 mg/kg) alone, or with co-administration of 100 mg/kg glycyrrhizin. Plasma concentrations of methotrexate, alanine aminotransferase, aspartate aminotransferase, and total bilirubin were measured. RESULTS: At both methotrexate doses, the blood concentration of methotrexate was significantly increased and total clearance was significantly reduced using co-administration of glycyrrhizin compared with methotrexate alone, which led to increased levels of hepatic enzymes. These results suggest that glycyrrhizin significantly increases the plasma level and delays the clearance of methotrexate, resulting in hepatic toxicity. CONCLUSION: The concomitant use of methotrexate and glycyrrhizin should be considered with caution.

Comprehensive Exploration of Medications That Affect the Bleeding Risk of Oral Anticoagulant Users.

Oral anticoagulants (OACs) pose a major bleeding risk, which may be increased or decreased by concomitant medications. To explore medications that affect the bleeding risk of OACs, we conducted a nested case-control study including 554 bleeding cases (warfarin, n = 327; direct OACs [DOACs], n = 227) and 1337 non-bleeding controls (warfarin, n = 814; DOACs, n = 523), using a Japanese health insurance database from January 2005 to June 2017. Major bleeding risk associated with exposure to concomitant medications within 30 d of the event/index date was evaluated, and adjusted odds ratios (aORs) were calculated using logistic regression analysis. Several antihypertensive drugs, such as amlodipine and bisoprolol, were associated with a decreased risk of bleeding (warfarin + amlodipine [aOR, 0.64; 95% confidence interval (CI): 0.41-0.98], DOACs + bisoprolol [aOR, 0.51; 95% CI, 0.33-0.80]). As hypertension is considered a significant risk factor for intracranial bleeding in antithrombotic therapy, antihypertensive drugs may suppress intracranial bleeding. In contrast, telmisartan, a widely used antihypertensive drug, was associated with an increased risk of bleeding [DOACs + telmisartan (aOR, 4.87; 95% CI, 1.84-12.91)]. Since telmisartan is an inhibitor of P-glycoprotein (P-gp), the elimination of rivaroxaban and apixaban, which are substrates of P-gp, is hindered, resulting in increased blood levels of both drugs, thereby increasing the risk of hemorrhage. In conclusion, antihypertensive drugs may improve the safety of OACs, and the pharmacokinetic-based drug interactions of DOACs must be considered.

Possible roles of intestinal P-glycoprotein and cytochrome P450 3A on the limited oral absorption of irinotecan.

OBJECTIVES: Irinotecan is a widely intravenously used drug for the treatment of certain types of solid tumours. The oral administration of irinotecan has recently been recognized as being a more effective method for the treatment than intravenous administration. However, the limited oral bioavailability of irinotecan poses a problem for its oral delivery. In this study, we report on an investigation of the mechanism responsible for the limited oral absorption of irinotecan using rats as models. METHODS: The intestinal absorption of irinotecan in the absence and presence of several compounds was examined using intestinal loop method. The pharmacokinetics of irinotecan was investigated when verapamil, an inhibitor of the P-glycoprotein (P-gp) and cytochrome P450 3A (CYP3A) was pre-administered. KEY FINDINGS: The intestinal absorption of irinotecan was enhanced in the presence of verapamil, indicating that efflux by intestinal P-gp contributes to its limited oral absorption. Indeed, the oral bioavailability of irinotecan was increased when verapamil was orally pre-administered. This increased oral bioavailability was accompanied by a slight but significant decrease in the formation of a metabolite produced by the action of CYP3A. CONCLUSION: The findings presented herein suggest that intestinal efflux by P-gp is mainly and intestinal metabolism by CYP3A is partially responsible for the limited oral absorption of irinotecan.

Antiplatelet Effect of Mirtazapine via Co-blocking of the 5-HT2A and α2-Adrenergic Receptors on Platelets.

Mirtazapine (MTZ) is a noradrenergic and specific serotonergic antidepressant. MTZ is reportedly associated with an increased risk of bleeding. However, the underlying mechanism remains unclear. In this study, we investigated the antiplatelet effect of MTZ in mice via light transmission aggregometry to elucidate the mechanism of MTZ-induced bleeding. The results of the ex vivo study showed that the oral administration of MTZ (20 or 100 mg/kg) significantly suppressed platelet aggregation mediated by the synergic interaction of 5-hydroxytryptamine (5-HT) and adrenaline. Additionally, MTZ significantly suppressed platelet aggregation, mediated by the synergic interaction of ADP and 5-HT or adrenaline. Similar results were obtained in vitro, under the condition of 5-HT- and adrenaline-induced platelet aggregation. Overall, the results suggest that MTZ exerts antiplatelet effect by co-blocking 5-HT2A and α2-adrenergic receptors on platelets and suppresses platelet aggregation mediated by ADP, increased by either 5-HT or adrenaline. Thus, a detailed monitoring of bleeding is recommended for patients taking MTZ.

High SLC20A1 Expression Is Associated With Poor Prognoses in Claudin-low and Basal-like Breast Cancers.

BACKGROUND/AIM: SLC20A1 has been identified as a prognostic marker in ER+ breast cancer. However, the role of SLC20A1 expression in breast cancer subtypes other than the ER+ types remains unclear. MATERIALS AND METHODS: Genomics datasets were downloaded and analyzed, and the effect of SLC20A1 knockdown using targeted siRNA on cell viability and tumor-sphere formation was assessed. RESULTS: SLC20A1high patients with ER+, claudin-low or basal-like breast cancers showed poor prognoses. SLC20A1high patients treated with radiotherapy had poor clinical outcomes. SLC20A1 knockdown suppressed the viability of MDA-MB 231 (claudin-low), MDA-MB 468 (basal-like) and MCF-7 (ER+) cells, and tumor-sphere formation by ALDH1high cells. These results suggest that SLC20A1 is involved in cancer progression and contributes to clinical outcomes in patients with ER+, claudin-low and basal-like breast cancers. CONCLUSION: SLC20A1 is a potential prognostic marker and therapeutic target in ER+, claudin-low and basal-like breast cancers.