Bisabosqual A: A novel asparagine synthetase inhibitor suppressing the proliferation and migration of human non-small cell lung cancer A549 cells.

Asparagine synthetase (ASNS) is a crucial enzyme for the de novo biosynthesis of endogenous asparagine (Asn), and ASNS shows the positive relationship with the growth of several solid tumors. Most of ASNS inhibitors are analogs of transition-state in ASNS reaction, but their low cell permeability hinders their anticancer activity. Therefore, novel ASNS inhibitors with a new pharmacophore urgently need to be developed. In this study, we established and applied a system for in vitro screening of ASNS inhibitors, and found a promising unique bisabolane-type meroterpenoid molecule, bisabosqual A (Bis A), able to covalently modify K556 site of ASNS protein. Bis A targeted ASNS to suppress cell proliferation of human non-small cell lung cancer A549 cells and exhibited a synergistic effect with L-asparaginase (L-ASNase). Mechanistically, Bis A promoted oxidative stress and apoptosis, while inhibiting autophagy, cell migration and epithelial-mesenchymal transition (EMT), impeding cancer cell development. Moreover, Bis A induced negative feedback pathways containing the GCN2-eIF2α-ATF4, PI3K-AKT-mTORC1 and RAF-MEK-ERK axes, but combination treatment of Bis A and rapamycin/torin-1 overcame the potential drug resistance triggered by mTOR pathways. Our study demonstrates that ASNS inhibition is promising for cancer chemotherapy, and Bis A is a potential lead ASNS inhibitor for anticancer development.

Absolute Lymphocyte Count Is an Independent Prognostic Factor for ER-positive HER2-negative Advanced Breast Cancer Patients Treated With CDK4/6 Inhibitors.

BACKGROUND/AIM: The aim of this study was to elucidate the clinical significance of peripheral blood biomarkers, including absolute lymphocyte count (ALC), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and C-reactive protein (CRP) in patients with estrogen receptor-positive human epidermal growth factor receptor 2-negative advanced breast cancer treated with the CDK4/6 inhibitors, abemaciclib and palbociclib. PATIENTS AND METHODS: A total of 83 patients treated with fulvestrant plus abemaciclib or palbociclib were included in this study. Progression-free survival (PFS) and overall survival (OS) were compared in relation to baseline levels of ALC, NLR, PLR and CRP. RESULTS: The cut-off values of ALC, NLR, PLR, and CRP for PFS were determined from the receiver operating characteristic curve using the Youden index for area under the curve and set at 1,212/µl, 1.964, 170 and 0.220 mg/dl, respectively. In the abemaciclib-treated group, ALC-high patients showed significantly better PFS than ALC-low patients (p=0.0151) and multivariate analysis revealed that ALC was an independent prognostic factor for PFS (p=0.0085). In the palbociclib-treated group, there was no significant relationship between any peripheral blood biomarkers and PFS. In both treatment groups, ALC-high patients showed significantly better OS than ALC-low patients (p=0.0169 and 0.0290, respectively). Multivariate analysis revealed ALC was an independent prognostic factor for OS in both abemaciclib- and palbociclib-treated groups (p=0.0112 and 0.0202, respectively). CONCLUSION: ALC is an independent prognostic factor for estrogen receptor-positive human epidermal growth factor receptor 2-negative advanced breast cancer patients treated with the CDK4/6 inhibitors abemaciclib and palbociclib.

Design, synthesis, and target identification of new hypoxia-inducible factor 1 (HIF-1) inhibitors containing 1-alkyl-1H-pyrazole-3-carboxamide moiety.

Hypoxia-inducible factor 1 (HIF-1) is a promising drug target for cancer chemotherapy. In our screening program aimed at identifying new HIF-1 inhibitors by using a hypoxia-responsive luciferase reporter gene assay, KUSC-5001 containing the 1-alkyl-1H-pyrazole-3-carboxamide moiety was found as a potential hit molecule. During an extensive structure-activity relationship (SAR) study, we developed a more effective HIF-1 inhibitor KUSC-5037 (IC50 = 1.2 µM). Under hypoxic conditions, KUSC-5037 suppressed the HIF-1α (a regulatory subunit of HIF-1) mRNA, causing decreases in the gene expression of HIF-1 target genes such as carbonic anhydrase 9 (CA9) and vascular endothelial growth factor (VEGF) genes. Furthermore, by applying our fluorescent and bifunctional probes, ATP5B, a catalytic ß subunit of mitochondrial FoF1-ATP synthase, was identified as a target protein of KUSC-5037. These results indicate that the derivatives of KUSC-5037 containing the 1-alkyl-1H-pyrazole-3-carboxamide moiety are promising lead molecules for the inhibition of HIF-1 signaling via FoF1-ATP synthase suppression.

Final results of a phase II study of nivolumab in Japanese patients with relapsed or refractory classical Hodgkin lymphoma.

BACKGROUND: Many patients with classical Hodgkin lymphoma show increased programmed death-1 ligand expression in Reed-Sternberg cells. We report the final results of a phase II study of nivolumab, an anti-programmed death-1 monoclonal antibody, in Japanese patients with relapsed or refractory classical Hodgkin lymphoma. METHODS: Japanese patients with previously treated classical Hodgkin lymphoma (aged ≥ 20 years) were administered nivolumab (3 mg/kg on Day 1 of 14-day cycles) until progressive disease, an unacceptable adverse event, or another clinically relevant reason. Treatment could continue beyond progressive disease at the investigator's discretion in selected patients. RESULTS: Seventeen patients (median age: 63.0 years) were enrolled. The median follow-up was 38.8 months. One patient with non-Hodgkin lymphoma was excluded from efficacy analyses. The centrally assessed overall response rate in 16 classical Hodgkin lymphoma patients was 87.5% (95% confidence interval = 61.7-98.4%) and the disease control rate was 93.8% (95% confidence interval = 69.8-99.8%). The median (95% confidence interval) duration of response and progression-free survival were 8.5 (2.4-12.6) and 11.7 (1.8-42.3) months, respectively. The 3-year overall survival rate was 80.4% (95% confidence interval = 50.6-93.2%). Nivolumab was continued beyond progressive disease in seven patients; six were alive at the data cut-off. Adverse drug reactions occurred in all 17 patients with grades 3-4 adverse drug reactions in eight patients and no grade 5 adverse drug reactions. Pulmonary toxicities occurred in five patients; four of these occurred ≥17 months after starting nivolumab. CONCLUSION: Nivolumab is effective and tolerable in Japanese relapsed or refractory classical Hodgkin lymphoma patients. Continued monitoring may be necessary to detect late-onset pulmonary toxicities. CLINICAL TRIAL REGISTRATION: JapicCTI-142755 (Japan Pharmaceutical Information Center).

Ubiquitin carboxyl-terminal hydrolase L1 promotes hypoxia-inducible factor 1-dependent tumor cell malignancy in spheroid models.

Hypoxia-inducible factor 1 (HIF-1) is a critical heterodimeric transcription factor for tumor malignancy. Recently, ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) has been reported to function as a deubiquitinating enzyme for the stabilization of its α subunit (HIF-1α). In the present study, we showed that UCHL1 inhibition can be an effective therapeutic strategy against HIF-1-dependent tumor malignancy. In 2D monolayer culture, a UCHL1 inhibitor suppressed HIF activity and decreased the transcription of HIF downstream genes by inhibiting the UCHL1-mediated accumulation of HIF-1α. Phenotypically, UCHL1 inhibition remarkably blocked cell migration. In 3D spheroid culture models, ectopic expression of UCHL1 significantly upregulated malignancy-related factors such as solidity, volume, as well as viable cell number in an HIF-1α-dependent manner. Conversely, inhibition of the UCHL1-HIF-1 pathway downregulated these malignancy-related factors and also abolished UCHL1-mediated cell proliferation and invasiveness. Finally, inhibition of UCHL1 promoted HIF-1α degradation and lowered the expression of HIF-1 target genes in the 3D model, as also observed in 2D monolayer culture. Our research indicates that the UCHL1-HIF-1 pathway plays a crucial role in tumor malignancy, making it a promising therapeutic target for cancer chemotherapy.

Factors Regulating Human Extravillous Trophoblast Invasion: Chemokine-peptidase and CD9-integrin Systems.

The invasion of an extravillous trophoblast (EVT) into maternal decidual tissues, especially towards maternal spiral arteries, is an essential process in the human placental formation and subsequent normal fetal development. However, the precise regulatory mechanisms to induce EVT invasion towards arteries and/or to protect EVT from further invasion are not well understood. We found that a chemokine receptor, CCR1, was specifically expressed on EVT migrating towards maternal arteries. Using EVT isolated from a primary villous explant culture, RANTES, which is one of the ligands for CCR1, was shown to enhance EVT invasion. Furthermore, we observed that the platelets were deposited among intravascular EVT and platelet-derived soluble factors, which contained RANTES, enhanced EVT invasion. On the one hand, dipeptidyl peptidase IV (DPPIV), which can metabolize RANTES on the cell surface, was expressed on non-invading EVT and was demonstrated to suppress EVT invasion. In contrast, laeverin/aminopeptidase Q, which is specifically expressed on EVT, was shown to induce EVT invasion. Also, CD9 which is a cell surface marker of platelets and a regulator of integrin function was expressed on EVT and gene knockdown of the CD9 molecule enhanced EVT invasion. These findings suggest that the chemokine-chemokine receptor, chemokine-peptidase, and CD9-integrin systems play important roles in the regulation of EVT invasion during early human placental formation.

CD9 suppresses human extravillous trophoblast invasion.

During human placentation, the extravillous trophoblast (EVT) invades the maternal decidua and reconstructs maternal spiral arteries. However, the precise mechanisms that control EVT behavior have not yet been elucidated in detail. CD9 has been reported to be a cell-motility-related molecule. Since we previously observed that CD9 was expressed on human EVT, we examined the possible involvement of CD9 in the invasion process of EVT. Placental and umbilical samples were obtained from patients who underwent legal abortions, normal delivery, or hysterectomy. The expression of CD9 at the implantation site and on isolated EVT from a villous explant culture, an EVT-derived immortalized cell line, Swan71, and HUVEC was examined by immunocytochemical staining, flow cytometry, and RT-PCR. The effects of anti-CD9 functional antibody (ALB6) on EVT and Swan71 cell invasion were further examined by matrigel invasion assay along with shRNAmir gene knockdown treatment. CD9 was highly expressed on EVT at the boundary region of EVT invasion and intravascular EVT. EVT and Swan71 cell invasions were promoted by ALB6 or shRNAmir treatment. CD9 expression on Swan71 cells was reduced under hypo-oxygenic conditions, while its expression was increased by the co-culture with HUVEC. These findings suggest that CD9 could attenuate EVT invasion under the influence of an oxygen environment and maternal endothelial cells, proposing that CD9 is a potential regulator of human placental formation.

Structure Elucidation of Verucopeptin, a HIF-1 Inhibitory Polyketide-Hexapeptide Hybrid Metabolite from an Actinomycete.

The transcriptional factor, hypoxia inducible factor-1 (HIF-1), is a promising target for cancer chemotherapy. From an actinomycete, verucopeptin (1) was identified as a HIF-1 signaling inhibitor. By a combination of chemical degradation and spectroscopic analyses, the absolute stereochemistry of metabolite 1 was determined to be 10R, 15S, 16S, 23S, 27S, 28R, 31S, 33S, 35R. Moreover, metabolite 1 was revealed to attenuate the HIF-1α and mTORC1 pathway, indicating that verucopeptin (1) would be a potent lead compound for anticancer chemotherapy.

Expression, purification and enzymatic characterization of a recombinant human ubiquitin-specific protease 47.

In this study, the physicochemical and enzymatic properties of recombinant human ubiquitin (Ub)-specific protease (USP) 47, a novel member of the C19 family of de-ubiquitinating enzymes (DUB), were characterized for the first time. Recombinant human USP47 was expressed in a baculovirus expression system and purified to homogeneity. The purified protein was shown to be a monomeric protein with a molecular mass of ∼146 kDa on sodium dodecyl sulphate-polyacrylamide gel electrophoresis. USP47 released Ub from Ub-aminoacyl-4-metheylcoumaryl-7-amide and Ub-tagged granzyme B. The substitution of the potential nucleophile Cys109 with Ser severely abrogated the Ub-releasing activity of USP47, indicating that USP47 is indeed a cysteine DUB. An assay using Ub dimer substrates showed that the enzyme cleaved a variety of isopeptide bonds between 2 Ub molecules, including the Lys48- and Lys63-linked isopeptide bonds. USP47 also released a Ub moiety from Lys48- and Lys63-linked polyUb chains. Of the inhibitors tested, N-ethylmaleimide, Zn ion and Ub aldehyde revealed a dose-dependent inhibition of USP47. In this study, clear differences in the enzymatic properties between USP47 and USP7 (the most closely related proteins among DUBs) were also found. Therefore, our results suggest that USP47 may play distinct roles in Ub-mediated cellular processes via DUB activity.

Design, synthesis, and structure-activity relationships of 1-ethylpyrazole-3-carboxamide compounds as novel hypoxia-inducible factor (HIF)-1 inhibitors.

Hypoxia-inducible factor (HIF)-1 is well known as a promising target for cancer chemotherapy. By screening an in-house chemical library using a hypoxia-responsive luciferase reporter gene assay, we identified CLB-016 (1) containing 1-ethylpyrazole-3-carboxamide as a HIF-1 inhibitor (IC50=19.1µM). In a subsequent extensive structure-activity relationship (SAR) study, we developed compound 11Ae with an IC50 value of 8.1µM against HIF-1-driven luciferase activity. Compounds 1 and 11Ae were shown to significantly suppress the HIF-1-mediated hypoxia response, including carbonic anhydrase IX (CAIX) gene expression and migration of human sarcoma HT1080 cells. These results revealed 1-ethylpyrazole-3-carboxamide as a novel scaffold to develop promising anti-cancer drugs targeting the HIF-1 signaling pathway.

Isolation, structure elucidation, and total synthesis of tryptopeptins A and B, new TGF-ß signaling modulators from Streptomyces sp.

Two new microbial metabolites, tryptopeptins A (1) and B (2), were isolated from the cultured broth of Streptomyces sp. KUSC-G11, as modulators of the transforming growth factor-ß (TGF-ß) signaling pathway. Their chemical structures consisting of isovalerate, N-Me-L-Val, L-allo-Thr, and a tryptophan-related residue were elucidated on the basis of spectroscopic analyses, while they were unambiguously determined by total syntheses. A structure-activity relationship (SAR) study using natural and synthesized tryptopeptins revealed the importance of the α,ß-epoxyketone function located at the C terminus. These new TGF-ß signaling modulators would be highly useful for development of new drug leads targeting TGF-ß-related diseases such as fibrosis and cancer.

Substrate-dependent nitric oxide synthesis by secreted endoplasmic reticulum aminopeptidase 1 in macrophages.

In this study, we examined the role of aminopeptidases with reference to endoplasmic reticulum aminopeptidase 1 (ERAP1) in nitric oxide (NO) synthesis employing murine macrophage cell line RAW264.7 cells activated by lipopolysaccharide (LPS) and interferon (IFN)-γ and LPS-activated peritoneal macrophages derived from ERAP1 knockout mouse. When NO synthesis was measured in the presence of peptides having N-terminal Arg, comparative NO synthesis was seen with that measured in the presence of Arg. In the presence of an aminopeptidase inhibitor amastatin, NO synthesis in activated RAW264.7 cells was significantly decreased. These results suggest that aminopeptidases are involved in the NO synthesis in activated RAW264.7 cells. Subsequently, significant reduction of NO synthesis was observed in ERAP1 knockdown cells compared with wild-type cells. This reduction was rescued by exogenously added ERAP1. Furthermore, when peritoneal macrophages prepared from ERAP1 knockout mouse were employed, reduction of NO synthesis in knockout mouse macrophages was also attributable to ERAP1. In the presence of amastatin, further reduction was observed in knockout mouse-derived macrophages. Taken together, these results suggest that several aminopeptidases play important roles in the maximum synthesis of NO in activated macrophages in a substrate peptide-dependent manner and ERAP1 is one of the aminopeptidases involved in the NO synthesis.

TLR-mediated secretion of endoplasmic reticulum aminopeptidase 1 from macrophages.

Macrophages play an important role in host defense under several immunological, inflammatory, and/or infectious conditions. In our previous work, we demonstrated that endoplasmic reticulum aminopeptidase 1 (ERAP1) was secreted from macrophages in response to LPS and IFN-γ, and it enhanced their phagocytic activity. In this study, we analyzed the mechanism of LPS/IFN-γ-induced ERAP1 secretion. LPS/IFN-γ-induced secretion of the enzyme from the murine macrophage cell line RAW264.7 was suppressed by polymyxin B. Several agonists of TLRs, such as Pam3CSK4, FSL-1, and ODN1826, induced its secretion. In contrast, neutralizing Abs to IFN-ß and TNF-α receptor type 1 suppressed its secretion. Using murine peritoneal macrophages derived from TNF-α and type 1 IFNR knockout mice, we confirmed the involvement of these two cytokines in ERAP1 secretion. In addition, secretion of ERAP1 from both RAW264.7 cells and murine peritoneal macrophages was induced by A23187 and thapsigargin and inhibited by BAPTA-AM and the calmodulin inhibitor W7. These results suggest that LPS/IFN-γ-induced secretion of ERAP1 is mediated by TLRs via induction of intermediate cytokines such as IFN-ß and TNF-α, which in turn lead to enhanced cytosolic Ca(2+) levels and calmodulin activation.

New insights into the role of aminopeptidases in the treatment for both preeclampsia and preterm labor.

INTRODUCTION: Evidence elucidating the pathophysiology and pharmacology of conventional drugs, ß-2 stimulants and magnesium sulfate, on safety and effectiveness for preeclampsia and preterm labor are rarely found. Both compounds pass through the placental barrier and could exert their adverse effects on the fetus. Exposure to these agents could be problematic long after the birth, and possibly result in diseases such as autism and cardiomyopathy. Since 1970 the possible roles of placental aminopeptidases, which degrade peptide hormones, in preeclampsia and preterm labor have been studied. AREAS COVERED: Many studies reveal that the fetus secretes peptide hormones, such as angiotensin II, vasopressin, and oxytocin, under hypoxia (stress) during the course of its growth, suggesting the critical effects these hormones have during pregnancy. The roles of placental aminopeptidases, the enzymes which degrade fetal hormones without passing through the placental barrier, were clarified. A first-step production system for recombinant aminopeptidases was established, by which engineered recombinant aminopeptidases were used for further experiments testing expected efficacy on controlling the level of hormones. EXPERT OPINION: The authors conclude that both aminopeptidase A and placental leucine aminopeptidase could be potentially safe and effective drugs for patients and their babies in the treatment of preeclampsia and preterm labor.

Endoplasmic reticulum aminopeptidases: biochemistry, physiology and pathology.

The human endoplasmic reticulum aminopeptidase (ERAP) 1 and 2 proteins were initially identified as homologues of human placental leucine aminopeptidase/insulin-regulated aminopeptidase. They are categorized as a unique class of proteases based on their subcellular localization on the luminal side of the endoplasmic reticulum. ERAPs play an important role in the N-terminal processing of the antigenic precursors that are presented on the major histocompatibility complex (MHC) class I molecules. ERAPs are also implicated in the regulation of a wide variety of physiological phenomena and pathogenic conditions. In this review, the current knowledge on ERAPs is summarized.

Association of epigenetic alterations in the human C7orf24 gene with the aberrant gene expression in malignant cells.

Human chromosome 7 open reading frame 24 (C7orf24)/γ-glutamyl cyclotransferase has been suggested to be a potential diagnostic marker for several cancers, including carcinomas in the bladder urothelium, breast and endometrial epithelium. We here investigated the epigenetic regulation of the human C7orf24 promoter in normal diploid ARPE-19 and IMR-90 cells and in the MCF-7 and HeLa cancer cell lines to understand the transcriptional basis for the malignant-associated high expression of C7orf24. Chromatin immunoprecipitation analysis revealed that histone modifications associated with active chromatin were enriched in the proximal region but not in the distal region of the C7orf24 promoter in HeLa and MCF-7 cells. In contrast, elevated levels of histone modifications leading to transcriptional repression and accumulation of heterochromatin proteins in the C7orf24 promoter were observed in the ARPE-19 and IMR-90 cells, compared to the levels in HeLa and MCF-7 cancer cells. In parallel, the CpG island of the C7orf24 promoter was methylated to a greater extent in the normal cells than in the cancer cells. These results suggest that the transcriptional silencing of the C7orf24 gene in the non-malignant cells is elicited through heterochromatin formation in its promoter region; aberrant expression of C7orf24 associated with malignant alterations results from changes in chromatin dynamics.

Features of Japanese patients with myelodysplastic syndrome in an aging population of Sado Island.

Myelodysplastic syndrome (MDS) is relatively common in the elderly, and aging of populations is progressing in developed nations, notably so in Japan. The major age group in Japan and Sado Island are distributed between 30 and 60 and between 50 and 80, respectively. The aim of this study was to analyze the features of MDS in the population of Sado Island to anticipate the characteristics of the disease in the near future. One-hundred and fifty-three patients (71 male, 82 female, 19-94 years old, median 73 years old) with de novo MDS between 1985 and 2005 were retrospectively evaluated. All patients were reclassified according to WHO-2001 criteria. The predictive power of the international prognostic scoring system and the WHO classification-based prognostic scoring system were evaluated. The major causes of death were leukemic transformation (38%) in refractory anemia with an excess of blasts and infection (48%) for total MDS. Age was another independent prognostic factor. Elderly patients exhibited a significantly poorer prognosis mainly due to infections such as pneumonia. Although novel remedies for MDS and hyperferremia have recently been developed, prevention of infection remains important in MDS, particularly for older patients.

Multiple NF-Y-binding CCAAT boxes are essential for transcriptional regulation of the human C7orf24 gene, a novel tumor-associated gene.

Human chromosome 7 ORF 24 (C7orf24) has been identified as a tumor-related protein, and shown to be a γ-glutamyl cyclotransferase. In the current study, we characterized the promoter region of the human C7orf24 gene to explore the transcriptional regulation of the gene. We revealed that the human C7orf24 promoter is a TATA-less promoter, containing five CCAAT boxes aligned in a forward orientation. By performing a luciferase reporter assay with 5'-deleted and site-directed mutated constructs in HeLa, MCF-7 and IMR-90 cells, we found that three proximal CCAAT boxes are important for basal transcription. Electrophoretic mobility gel shift assay and chromatin immunoprecipitation assay demonstrated that NF-Y specifically bound to all three CCAAT boxes. In addition, the mRNA and protein expression levels of C7orf24 were significantly reduced in HeLa cells depleted of NF-YB, a subunit of NF-Y. These results suggested that NF-Ys bound to the three proximal CCAAT boxes play a central role in the transcription of the gene. Furthermore, as in the case of other genes transcribed under the control of multiple NF-Ys, such as human E2f1 and cyclin b1, the C7orf24 gene expression profile oscillated during the cell cycle, implying that C7orf24 is a novel cell cycle-associated gene.

Secretion of endoplasmic reticulum aminopeptidase 1 is involved in the activation of macrophages induced by lipopolysaccharide and interferon-gamma.

Endoplasmic reticulum aminopeptidase 1 (ERAP1) is a multifunctional enzyme with an important role in processing antigenic peptides presented to class I major histocompatibility complex in the endoplasmic reticulum. In this study, we found that endoplasmic reticulum-retained ERAP1 was secreted from macrophages in response to activation by treatment with lipopolysaccharide (LPS) and interferon (IFN)-γ and enhanced their phagocytic activity. Enhancement of the phagocytic activity of murine macrophage RAW264.7 cells induced by LPS/IFN-γ was inhibited by a potent aminopeptidase inhibitor, amastatin. The addition of recombinant wild-type but not inactive mutant ERAP1 to culture medium enhanced phagocytosis. These results suggest that enhancement of phagocytic activity is at least in part mediated by secreted ERAP1 through the generation of active peptides processed by the enzyme. Our data reveal ERAP1-mediated activation of macrophages for the first time and will provide new insights into the role of this enzyme in innate immunity.