ID3 is a novel target gene of p53 and modulates lung cancer cell metastasis.

The tumor suppressor p53 prevents cancer development by regulating dozens of target genes with diverse biological functions. Although numerous p53 target genes have been identified to date, the dynamics and function of the regulatory network centered on p53 have not yet been fully elucidated. We herein identified inhibitor of DNA-binding/differentiation-3 (ID3) as a direct p53 target gene. p53 bound the distal promoter of ID3 and positively regulated its transcription. ID3 expression was significantly decreased in clinical lung cancer tissues, and was closely associated with overall survival outcomes in these patients. Functionally, ID3 deficiency promoted the metastatic ability of lung cancer cells through its effects on the transcriptional regulation of CDH1. Furthermore, the ectopic expression of ID3 in p53-knockdown cells restored E-cadherin expression. Collectively, the present results demonstrate that ID3 plays a tumor-suppressive role as a downstream effector of p53 and impedes lung cancer cell metastasis by regulating E-cadherin expression.

Pegfilgrastim for the management of neutropenia during neoadjuvant chemotherapy with docetaxel, cisplatin, and 5-fluorouracil in esophageal cancer patients.

BACKGROUND: Neoadjuvant docetaxel, cisplatin, and 5-fluorouracil (DCF) therapy is a new standard for locally advanced esophageal squamous cell carcinoma. The optimal timing of pegfilgrastim with the DCF regimen to prevent febrile neutropenia (FN) remains controversial. The effectiveness of concomitant pegfilgrastim administration with continuous 5-fluorouracil (5-FU) infusion in the DCF regimen was therefore assessed. METHODS: All patients who received neoadjuvant DCF for esophageal cancer were retrospectively assessed. Patients who had been scheduled to receive pegfilgrastim on days 3-5 (early group) or days 7-9 (regular group) of the DCF regimen were included. Uni- and multivariate analyses were used to assess risk factors for FN. RESULTS: Eighty-eight patients were included in the analysis. The 26 patients in the early group received pegfilgrastim as scheduled. In the 62 patients of the regular group, 51 received pegfilgrastim at a median of 7 days after starting DCF chemotherapy. However, 11 patients in the regular group could not receive pegfilgrastim. Twenty-two patients of the regular group and 2 patients of the early group developed FN after the first session of DCF. Early administration of pegfilgrastim and grade 4 neutropenia were significantly associated with onset of FN, with multivariate analysis identifying early administration of pegfilgrastim as an independent preventive factor and grade 4 neutropenia as a risk factor, after adjusting for sex and age. CONCLUSION: Early pegfilgrastim administration is a safe approach that reduces the incidence of FN in DCF therapy. Using pegfilgrastim with continuous 5-FU infusion in the DCF regimen represents a reasonable option to prevent FN.

Involvement of cardiac glycosides targeting Na/K-ATPase in their inhibitory effects on c-Myc expression via its transcription, translation and proteasomal degradation.

Cardiac glycosides (CGs) have been used for decades to treat heart failure and arrhythmic diseases. Recent non-clinical and epidemiological findings have suggested that CGs exhibit anti-tumor activities. Therefore, CGs may be repositioned as drugs for the treatment of cancer. A detailed understanding of the anti-cancer mechanisms of CGs is essential for their application to the treatment of targetable cancer types. To elucidate the factors associated with the anti-tumor effects of CGs, we performed transcriptome profiling on human multiple myeloma AMO1 cells treated with periplocin, one of the CGs. Periplocin significantly down-regulated the transcription of MYC (c-Myc), a well-established oncogene. Periplocin also suppressed c-Myc expression at the protein levels. This repression of c-Myc was also observed in several cell lines. To identify target proteins for the inhibition of c-Myc, we generated CG-resistant (C9) cells using a sustained treatment with digoxin. We confirmed that C9 cells acquired resistance to the inhibition of c-Myc expression and cell proliferation by CGs. Moreover, the sequencing of genomic DNA in C9 cells revealed the mutation of D128N in α1-Na/K-ATPase, indicating the target protein. These results suggest that CGs suppress c-Myc expression in cancer cells via α1-Na/K-ATPase, which provides further support for the anti-tumor activities of CGs.

SET8 is a novel negative regulator of TGF-ß signaling in a methylation-independent manner.

Transforming growth factor ß (TGF-ß) is a multifunctional cytokine that induces a diverse set of cellular processes principally through Smad-dependent transcription. Transcriptional responses induced by Smads are tightly regulated by Smad cofactors and histone modifications; however, the underlying mechanisms have not yet been elucidated in detail. We herein report lysine methyltransferase SET8 as a negative regulator of TGF-ß signaling. SET8 physically associates with Smad2/3 and negatively affects transcriptional activation by TGF-ß in a catalytic activity-independent manner. The depletion of SET8 results in an increase in TGF-ß-induced plasminogen activator inhibitor-1 (PAI-1) and p21 expression and enhances the antiproliferative effects of TGF-ß. Mechanistically, SET8 occupies the PAI-1 and p21 promoters, and a treatment with TGF-ß triggers the replacement of the suppressive binding of SET8 with p300 on these promoters, possibly to promote gene transcription. Collectively, the present results reveal a novel role for SET8 in the negative regulation of TGF-ß signaling.

Diarrhea-predominant Irritable Bowel Syndrome-like Symptoms in Patients With Quiescent Crohn's Disease: Comprehensive Analysis of Clinical Features and Intestinal Environment Including the Gut Microbiome, Organic Acids, and Intestinal Permeability.

Background/Aims: Diarrhea-predominant irritable bowel syndrome (IBS-D)-like symptoms frequently occur in patients with quiescent Crohn's disease (CD). To investigate the factors underlying IBS-D-like symptoms in patients with quiescent CD, we performed a comprehensive analysis of the clinical features and intestinal environment in those patients. Methods: We performed a prospective observational study of 27 patients with quiescent CD (CD activity index [CDAI] ≤ 150; C-reactive protein ≤ 0.3 mg/dL). The presence and severity of IBS-D-like symptoms, health-related quality of life, disease-specific quality of life, and status of depression and anxiety were evaluated. The level of intestinal permeability, fecal calprotectin and organic acids and the profiles of gut microbiome were analyzed. Results: Twelve of the 27 patients with quiescent CD (44.4%) had IBS-like symptoms, and these patients showed a significantly higher CDAI, IBS severity index and anxiety score than those without. The inflammatory bowel disease questionnaire score was significantly lower in the patients with IBS-D-like symptoms. There were no significant differences in small intestinal/colonic permeability or the levels of organic acids between the patients with and without IBS-D-like symptoms. Fusicatenibacter was significantly less abundant in the patients with IBS-D-like symptoms whereas their fecal calprotectin level was significantly higher (384.8 ± 310.6 mg/kg) than in patients without (161.0 ± 251.0 mg/kg). The receiver operating characteristic curve constructed to predict IBS-D-like symptoms in patients with quiescent CD using the fecal calprotectin level (cutoff, 125 mg/kg) showed a sensitivity and specificity of 73.3% and 91.7%, respectively. Conclusion: Minimal inflammation is closely associated with the development of IBS-D-like symptoms in patients with quiescent CD.

Insights into Regulators of p53 Acetylation.

The tumor suppressor p53 is a transcription factor that regulates the expression of dozens of target genes and diverse physiological processes. To precisely regulate the p53 network, p53 undergoes various post-translational modifications and alters the selectivity of target genes. Acetylation plays an essential role in cell fate determination through the activation of p53. Although the acetylation of p53 has been examined, the underlying regulatory mechanisms remain unclear and, thus, have attracted the interest of researchers. We herein discuss the role of acetylation in the p53 pathway, with a focus on p53 acetyltransferases and deacetylases. We also review recent findings on the regulators of these enzymes to understand the mode of p53 acetylation from a broader perspective.

Efficacy of Serotonin Type 3 Receptor Antagonist Ramosetron on Diarrhea-Predominant Irritable Bowel Syndrome (IBS-D)-Like Symptoms in Patients with Quiescent Inflammatory Bowel Disease: A Randomized, Double-Blind, Placebo-Controlled Trial.

Patients with quiescent inflammatory bowel disease (IBD) frequently suffer diarrhea-predominant irritable bowel syndrome (IBS-D)-like symptoms, such as abdominal pain or stool irregularities. Here, we assessed the effect of ramosetron, a serotonin type 3 (5-HT3) receptor antagonist, on IBS-D-like symptoms in patients with quiescent IBD. Seventy patients with quiescent IBD, who met the Rome III diagnostic criteria for IBS-D, were randomly assigned to receive either ramosetron (5 µg; n = 35) or a placebo (n = 35) orally once daily for 4 weeks. The primary endpoint was the responder rate for global assessment of relief from overall IBS-D-like symptoms. The responder rates for relief of abdominal pain/discomfort and improvement of bowel habits were also evaluated. The responder rate for relief from overall IBS-D-like symptoms at the final evaluation point was significantly higher in the ramosetron group (35.5%) than in the placebo group (11.4%) (p = 0.037). The responder rate for improvement of bowel habits was significantly higher in the ramosetron group (38.7%) than in the placebo group (14.3%) (p = 0.028). The reduction of stool frequency was significantly greater in the ramosetron group than in the placebo group (p = 0.044). Ramosetron is effective for relief of overall IBS-D-like symptoms in patients with quiescent IBD.

CARD11 mutation and HBZ expression induce lymphoproliferative disease and adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATL) is caused by human T-cell leukemia virus type 1 (HTLV-1). In addition to HTLV-1 bZIP factor (HBZ), a leukemogenic antisense transcript of HTLV-1, abnormalities of genes involved in TCR-NF-κB signaling, such as CARD11, are detected in about 90% of patients. Utilizing mice expressing CD4+ T cell-specific CARD11(E626K) and/or CD4+ T cell-specific HBZ, namely CARD11(E626K)CD4-Cre mice, HBZ transgenic (Tg) mice, and CARD11(E626K)CD4-Cre;HBZ Tg double transgenic mice, we clarify these genes' pathogenetic effects. CARD11(E626K)CD4-Cre and HBZ Tg mice exhibit lymphocytic invasion to many organs, including the lungs, and double transgenic mice develop lymphoproliferative disease and increase CD4+ T cells in vivo. CARD11(E626K) and HBZ cooperatively activate the non-canonical NF-κB pathway, IRF4 targets, BATF3/IRF4/HBZ transcriptional network, MYC targets, and E2F targets. Most KEGG and HALLMARK gene sets enriched in acute-type ATL are also enriched in double transgenic mice, indicating that these genes cooperatively contribute to ATL development.

Amplified EPOR/JAK2 Genes Define a Unique Subtype of Acute Erythroid Leukemia.

Acute erythroid leukemia (AEL) is a unique subtype of acute myeloid leukemia characterized by prominent erythroid proliferation whose molecular basis is poorly understood. To elucidate the underlying mechanism of erythroid proliferation, we analyzed 121 AEL using whole-genome, whole-exome, and/or targeted-capture sequencing, together with transcriptome analysis of 21 AEL samples. Combining publicly available sequencing data, we found a high frequency of gains and amplifications involving EPOR/JAK2 in TP53-mutated cases, particularly those having >80% erythroblasts designated as pure erythroid leukemia (10/13). These cases were frequently accompanied by gains and amplifications of ERG/ETS2 and associated with a very poor prognosis, even compared with other TP53-mutated AEL. In addition to activation of the STAT5 pathway, a common feature across all AEL cases, these AEL cases exhibited enhanced cell proliferation and heme metabolism and often showed high sensitivity to ruxolitinib in vitro and in xenograft models, highlighting a potential role of JAK2 inhibition in therapeutics of AEL. SIGNIFICANCE: This study reveals the major role of gains, amplifications, and mutations of EPOR and JAK2 in the pathogenesis of pure erythroleukemia. Their frequent response to ruxolitinib in patient-derived xenograft and cell culture models highlights a possible therapeutic role of JAK2 inhibition for erythroleukemia with EPOR/JAK2-involving lesions. This article is highlighted in the In This Issue feature, p. 369.

Epidemiology and Clinical Characteristics Based on the Rome III and IV Criteria of Japanese Patients with Functional Dyspepsia.

The subtypes of functional dyspepsia (FD) differ depending on whether the Rome III criteria or the Rome IV criteria are used. We investigated the ability to diagnose FD patients using the Rome III and IV criteria. The subtypes of FD were evaluated using the Rome questionnaire. The Gastrointestinal Symptom Rating Score, health-related quality of life (HR-QOL; SF-8), and psychological scores (HADS, STAI) were evaluated. The questionnaire was collected from a total of 205 patients, and 54.1% were FD patients. The ratio of FD patients under the Rome III criteria was 19% for epigastric pain syndrome (EPS), 38% for postprandial distress syndrome (PDS), and 43% for an overlap of EPS and PDS, but under the Rome IV criteria overlap decreased to 17% and PDS increased to 64%. Patients whose subtype changed from overlap under the Rome III criteria to PDS under the Rome IV criteria were compared with PDS patients whose subtype did not change between the Rome III and IV criteria. The comparison showed that the former had significantly lower early satiation rates and significantly higher acid reflux and abdominal pain scores, demonstrating that EPS symptoms due to acid reflux after meals were clearly present. As a result of changing from the Rome III criteria to the Rome IV criteria, the number of overlap patients decreased, and the number of PDS patients increased.

The deubiquitinating enzyme USP17 regulates c-Myc levels and controls cell proliferation and glycolysis.

The c-Myc oncoprotein is frequently overexpressed in human cancers and is essential for cancer cell proliferation. The dysregulation of ubiquitin-proteasome-mediated degradation is one of the contributing factors to the upregulated expression of c-Myc in human cancers. We herein identified USP17 as a novel deubiquitinating enzyme that regulates c-Myc levels and controls cell proliferation and glycolysis. The overexpression of USP17 stabilized the c-Myc protein by promoting its deubiquitination. In contrast, the knockdown of USP17 promoted c-Myc degradation and reduced c-Myc levels. The knockdown of USP17 also suppressed cell proliferation and glycolysis. Collectively, the present results reveal a novel role for USP17 in the regulation of c-Myc stability and suggest its potential as a therapeutic target for cancer treatment.

Periplocin and cardiac glycosides suppress the unfolded protein response.

The unfolded protein response (UPR) controls protein homeostasis through transcriptional and translational regulation. However, dysregulated UPR signaling has been associated with the pathogenesis of many human diseases. Therefore, the compounds modulating UPR may provide molecular insights for these pathologies in the context of UPR. Here, we screened small-molecule compounds that suppress UPR, using a library of Myanmar wild plant extracts. The screening system to track X-box binding protein 1 (XBP1) splicing activity revealed that the ethanol extract of the Periploca calophylla stem inhibited the inositol-requiring enzyme 1 (IRE1)-XBP1 pathway. We isolated and identified periplocin as a potent inhibitor of the IRE1-XBP1 axis. Periplocin also suppressed other UPR axes, protein kinase R-like endoplasmic reticulum kinase (PERK), and activating transcription factor 6 (ATF6). Examining the structure-activity relationship of periplocin revealed that cardiac glycosides also inhibited UPR. Moreover, periplocin suppressed the constitutive activation of XBP1 and exerted cytotoxic effects in the human multiple myeloma cell lines, AMO1 and RPMI8226. These results reveal a novel suppressive effect of periplocin or the other cardiac glycosides on UPR regulation, suggesting that these compounds will contribute to our understanding of the pathological or physiological importance of UPR.

Senna Versus Magnesium Oxide for the Treatment of Chronic Constipation: A Randomized, Placebo-Controlled Trial.

INTRODUCTION: This is the first prospective, double-blinded, randomized, placebo-controlled trial to evaluate the safety and efficacy of a stimulant laxative compared with an osmotic agent for the treatment of chronic idiopathic constipation. METHODS: Patients were randomly administered stimulant laxative (senna, 1.0 g), osmotic agent (magnesium oxide [MgO], 1.5 g), or placebo for 28 consecutive days. The primary endpoint was overall symptom improvement. Secondary endpoints were spontaneous bowel movement (SBM), complete SBM, and patient assessment of constipation quality of life (QOL). RESULTS: Ninety patients (mean age, 42 years; 93% women; mean duration of symptoms, 9.9 years) were enrolled; all completed the study. The response rate for overall improvement was 11.7% in the placebo group, 69.2% in the senna group, and 68.3% in the MgO group (P < 0.0001). Change in SBM was significantly greater in the senna and MgO groups than that in the placebo group (P < 0.001). Similarly, change in complete SBM was significantly greater in the senna and MgO groups than that in the placebo group (P < 0.01). On the patient assessment of constipation QOL, significant improvements were seen in the senna and MgO groups compared with those in the placebo group (senna, P < 0.05; MgO, P < 0.001). The frequency of severe treatment-related adverse events was 0%. DISCUSSION: Senna and MgO significantly improved the frequency of bowel movements and QOL score and seem to be effective in the treatment of constipation.

Anti-Inflammatory Activity of Kurarinone Involves Induction of HO-1 via the KEAP1/Nrf2 Pathway.

Kurarinone, a flavonoid isolated from the roots of Sophora flavescens, was suggested to exert potent antioxidant and immunosuppressive effects. However, the underlying mechanisms remain unclear. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor that regulates the antioxidant defense system with anti-inflammatory activity. In the present study, we demonstrated that kurarinone activated Nrf2 and increased the expression of antioxidant enzymes, including heme oxygenase-1 (HO-1). Mechanistically, kurarinone downregulated the expression of kelch-like ECH-associated protein 1 (KEAP1), subsequently leading to the activation of Nrf2. Kurarinone also inhibited the expression of the inflammatory cytokine, interleukin (IL)-1ß, and inducible nitric oxide synthase (iNos) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The overexpression of HO-1 suppressed the LPS-induced production of inflammatory mediators in RAW264.7 cells, and the immunosuppressive effects of kurarinone were partially inhibited by a treatment with Tin Protomorphyrin IX (TinPPIX), an inhibitor of HO-1. These results indicate that kurarinone activates the KEAP1/Nrf2 pathway to induce HO-1 expression, thereby exerting immunosuppressive effects.

Combined Cohesin-RUNX1 Deficiency Synergistically Perturbs Chromatin Looping and Causes Myelodysplastic Syndromes.

STAG2 encodes a cohesin component and is frequently mutated in myeloid neoplasms, showing highly significant comutation patterns with other drivers, including RUNX1. However, the molecular basis of cohesin-mutated leukemogenesis remains poorly understood. Here we show a critical role of an interplay between STAG2 and RUNX1 in the regulation of enhancer-promoter looping and transcription in hematopoiesis. Combined loss of STAG2 and RUNX1, which colocalize at enhancer-rich, CTCF-deficient sites, synergistically attenuates enhancer-promoter loops, particularly at sites enriched for RNA polymerase II and Mediator, and deregulates gene expression, leading to myeloid-skewed expansion of hematopoietic stem/progenitor cells (HSPC) and myelodysplastic syndromes (MDS) in mice. Attenuated enhancer-promoter loops in STAG2/RUNX1-deficient cells are associated with downregulation of genes with high basal transcriptional pausing, which are important for regulation of HSPCs. Downregulation of high-pausing genes is also confirmed in STAG2-cohesin-mutated primary leukemia samples. Our results highlight a unique STAG2-RUNX1 interplay in gene regulation and provide insights into cohesin-mutated leukemogenesis. SIGNIFICANCE: We demonstrate a critical role of an interplay between STAG2 and a master transcription factor of hematopoiesis, RUNX1, in MDS development, and further reveal their contribution to regulation of high-order chromatin structures, particularly enhancer-promoter looping, and the link between transcriptional pausing and selective gene dysregulation caused by cohesin deficiency.This article is highlighted in the In This Issue feature, p. 747.

Discovery of Novel Allosteric Inhibitors of Deoxyhypusine Synthase.

Deoxyhypusine synthase (DHPS) utilizes spermidine and NAD as cofactors to incorporate a hypusine modification into the eukaryotic translation initiation factor 5A (eIF5A). Hypusine is essential for eIF5A activation, which, in turn, plays a key role in regulating protein translation of selected mRNA that are associated with the synthesis of oncoproteins, thereby enhancing tumor cell proliferation. Therefore, inhibition of DHPS is a promising therapeutic option for the treatment of cancer. To discover novel lead compounds that target DHPS, we conducted synthetic studies with a hit obtained via high-throughput screening. Optimization of the ring structures of the amide compound (2) led to bromobenzothiophene (11g) with potent inhibitory activity against DHPS. X-ray crystallographic analysis of 11g complexed with DHPS revealed a dramatic conformational change in DHPS, which suggests the presence of a novel allosteric site. These findings provide the basis for the development of novel therapy distinct from spermidine mimetic inhibitors.

Transcriptional Coactivator TAZ Negatively Regulates Tumor Suppressor p53 Activity and Cellular Senescence.

Transcriptional coactivator with a PDZ-binding motif (TAZ) is one of the mammalian orthologs of Drosophila Yorkie, a transcriptional coactivator of the Hippo pathway. TAZ has been suggested to function as a regulator that modulates the expression of cell proliferation and anti-apoptotic genes in order to stimulate cell proliferation. TAZ has also been associated with a poor prognosis in several cancers, including breast cancer. However, the physiological role of TAZ in tumorigenesis remains unclear. We herein demonstrated that TAZ negatively regulated the activity of the tumor suppressor p53. The overexpression of TAZ down-regulated p53 transcriptional activity and its downstream gene expression. In contrast, TAZ knockdown up-regulated p21 expression induced by p53 activation. Regarding the underlying mechanism, TAZ inhibited the interaction between p53 and p300 and suppressed the p300-mediated acetylation of p53. Furthermore, TAZ knockdown induced cellular senescence in a p53-dependent manner. These results suggest that TAZ negatively regulates the tumor suppressor functions of p53 and attenuates p53-mediated cellular senescence.

New Series of Potent Allosteric Inhibitors of Deoxyhypusine Synthase.

Deoxyhypusine synthase (DHPS) is the primary enzyme responsible for the hypusine modification and, thereby, activation of the eukaryotic translation initiation factor 5A (eIF5A), which is key in regulating the protein translation processes associated with tumor proliferation. Although DHPS inhibitors could be a promising therapeutic option for treating cancer, only a few studies reported druglike compounds with this inhibition property. Thus, in this work, we designed and synthesized a new chemical series possessing fused ring scaffolds designed from high-throughput screening hit compounds, discovering a 5,6-dihydrothieno[2,3-c]pyridine derivative (26d) with potent inhibitory activity; furthermore, the X-ray crystallographic analysis of the DHPS complex with 26d demonstrated a distinct allosteric binding mode compared to a previously reported inhibitor. These findings could be significantly useful in the functional analysis of conformational changes in DHPS as well as the structure-based design of allosteric inhibitors.

The ubiquitin-specific protease USP17 prevents cellular senescence by stabilizing the methyltransferase SET8 and transcriptionally repressing p21.

Su(var)3-9, Enhancer-of-zeste, and Trithorax (SET) domain-containing protein 8 (SET8) is the sole enzyme that monomethylates Lys-20 of histone H4 (H4K20). SET8 has been implicated in the regulation of multiple biological processes, such as gene transcription, the cell cycle, and senescence. SET8 quickly undergoes ubiquitination and degradation by several E3 ubiquitin ligases; however, the enzyme that deubiquitinates SET8 has not yet been identified. Here we demonstrated that ubiquitin-specific peptidase 17-like family member (USP17) deubiquitinates and therefore stabilizes the SET8 protein. We observed that USP17 interacts with SET8 and removes polyubiquitin chains from SET8. USP17 knockdown not only decreased SET8 protein levels and H4K20 monomethylation but also increased the levels of the cyclin-dependent kinase inhibitor p21. As a consequence, USP17 knockdown suppressed cell proliferation. We noted that USP17 was down-regulated in replicative senescence and that USP17 inhibition alone was sufficient to trigger cellular senescence. These results reveal a regulatory mechanism whereby USP17 prevents cellular senescence by removing ubiquitin marks from and stabilizing SET8 and transcriptionally repressing p21.