👤 Norikatsu Miyoshi

The mechanism of hepatocarcinogenesis after sustained virological response (SVR) in hepatitis C virus (HCV) patients is unclear. We compared gene profiles of hepatocellular carcinoma (HCC) between HCV-SVR, steatotic liver disease (SLD), and HCV-non-SVR patients. This study analyzed 126 resected HCCs from patients with HCV and SLD, classifying them as HCV-SVR (n = 22), HCV-non-SVR (n = 56), and SLD (n = 48). Deep sequencing of 2910 hotspots in 55 cancer-related genes was conducted to examine mutations and copy number variations in both cancerous and background liver tissues. The HCV-SVR group comprised more patients who consumed alcohol (45.5% vs. 15.7%, p = 0.008), were obese (54.5% vs. 17.9%, p = 0.002), and had dyslipidemia (18.2% vs. 3.6%, p = 0.029) and hyperuricemia (18.2% vs. 3.6%, p = 0.029) than the HCV-non-SVR group. Mutational profiling of the HCV-SVR HCC showed significantly lower alteration rates of AXIN1 (13.6% vs. 42.9%, p = 0.016), ARID2 (9.1% vs. 39.3%, p = 0.013), and TP53 (9.1% vs. 32.1%, p = 0.030) than HCV-non-SVR patients. Compared with HCV-non-SVR-HCC, SLD-HCCs showed significantly lower rates of TERT promoter mutations (62.5% vs. 85.7%, p = 0.004), ARID2 alterations (12.5% vs. 39.3%, p = 0.003), and AXIN1 alterations (12.5% vs. 42.9%, p = 0.002). HCV-SVR/MASH/MASLD/ALD-HCC had significantly lower alteration rates of the Wnt/β-catenin (41.4% vs. 60.7%, p = 0.048) and chromatin remodeling pathways (27.1% vs. 48.2%, p = 0.026) than HCV-non-SVR-HCC. HCV-SVR HCC is linked to alcohol use and metabolic diseases, showing a mutational profile similar to SLD-HCC. Show less

The guanine-rich stretch of single-stranded DNA (ssDNA) forms a G-quadruplex (G4) in a fraction of genic and intergenic chromosomal regions. The probability of G4 formation increases during events causing ssDNA generation, such as transcription and replication. In turn, G4 abrogates these events, leading to DNA damage. DHX36 unwinds G4-DNA in vitro and in human cells. However, its spatial correlation with G4-DNA in vivo and its role in genome maintenance remain unclear. Here, we demonstrate a connection between DHX36 and G4-DNA and its implications for genomic integrity. The nuclear localization of DHX36 overlapped with that of G4-DNA, RNA polymerase II, and a splicing-related factor. Depletion of DHX36 resulted in accumulated DNA damage, slower cell growth, and enhanced cell growth inhibition upon treatment with a G4-stabilizing compound; DHX36 expression reversed these defects. In contrast, the reversal upon expression of DHX36 mutants that could not bind G4 was imperfect. Thus, DHX36 may suppress DNA damage by promoting the clearance of G4-DNA for cell growth and survival. Our findings deepen the understanding of G4 resolution in the maintenance of genomic integrity. Show less

Objective Glucose-dependent insulinotropic polypeptide (GIP) is speculated to worsen growth hormone (GH) hypersecretion in acromegaly and to be a cause of paradoxical increases in GH (PI-GH) during 75-g oral glucose tolerance testing (75-g OGTT). Dipeptidyl peptidase-4 inhibitors (DPP4is), which increase the circulating concentration of active GIP, are frequently administered to diabetic patients, including those with acromegaly. We aimed to determine whether or not the administration of a DPP4i increases GH concentration, especially in patients demonstrating PI-GH during a DPP4i-OGTT, in which a DPP4i was administered immediately before 75-g OGTT. Methods This prospective cross-sectional study was carried out on acromegalic patients admitted to Hokkaido University hospital between June 2011 and May 2018. The participants underwent both 75-g OGTT and DPP4i-OGTT. For those who underwent surgery, immunohistochemical staining and quantitative polymerase chain reaction (PCR) for the GIP receptor (GIPR) were performed on the resected pituitary adenomas. Results Twenty-five percent of the participants had PI-GH confirmed (3 of 12 cases). Two of the three participants who demonstrated PI-GH exhibited higher circulating GH concentrations during DPP4i-OGTT than during OGTT. The increase in plasma glucose was reduced during DPP4i-OGTT compared to during 75-g OGTT, suggesting that the increase in GH during DPP4i-OGTT was due not to high glucose concentrations but instead increased GIP caused by the administration of DPP4i. The adenoma from one participant with PI-GH displayed positive immunostaining for GIPR and a higher GIPR messenger ribonucleic acid (mRNA) expression than the others. Conclusion DPP4i may enhance the GH secretion response during glucose loading, especially in individuals with PI-GH. Show less

Chromosome instability is one of the hallmarks of cancer. Stromal antigen (STAG) 3 is a core component of the meiosis-specific cohesin complex, which regulates sister chromatid cohesion. Although aberrantly activated genes encoding the cohesin complex have been identified in cancers, little is known about the role of STAG3 in colorectal cancer (CRC). Here, we evaluated the prognostic impact and role of STAG3 in CRC. Analysis of 172 CRC surgical specimens revealed that high STAG3 expression was associated with poor prognosis. STAG3 knockdown inhibited cell migration and increased drug sensitivity to oxaliplatin, 5-fluorouracil, irinotecan hydrochloride hydrate, and BRAF inhibitor in CRC cell lines. The enhanced drug sensitivity was also confirmed in a human organoid established from a CRC specimen. Moreover, suppression of STAG3 increased γH2AX foci. Particularly, in BRAF-mutant CRC cells, STAG3 silencing suppressed the expression of snail family transcriptional repressor 1 and phosphorylation of extracellular signal-regulated kinase via upregulation of dual-specificity phosphatase 6. Our findings suggest that STAG3 is related to poor clinical outcomes and promotes metastasis and chemotherapeutic resistance in CRC. STAG3 may be a novel prognostic marker and potential therapeutic target for CRC. Show less

There is no established transplacental treatment for heart failure (HF) in utero, and no animal models or experimental systems of fetal HF have been established. This study aimed to investigate the effect of maternal tadalafil administration on fetal cardiovascular function and uteroplacental circulation in a murine model of fetal HF. We first used an ultra-high-frequency ultrasound imaging system in utero and demonstrated that Hey2 A phenotype comprising marked dilatation and reduced FS of the left ventricles was identified in Hey2 Show less

Activated tyrosine kinases have been frequently implicated in the pathogenesis of cancer, including acute myeloid leukemia (AML), and are validated targets for therapeutic intervention with small-molecule kinase inhibitors. To identify novel activated tyrosine kinases in AML, we used a discovery platform consisting of immunoaffinity profiling coupled to mass spectrometry that identifies large numbers of tyrosine-phosphorylated proteins, including active kinases. This method revealed the presence of an activated colony-stimulating factor 1 receptor (CSF1R) kinase in the acute megakaryoblastic leukemia (AMKL) cell line MKPL-1. Further studies using siRNA and a small-molecule inhibitor showed that CSF1R is essential for the growth and survival of MKPL-1 cells. DNA sequence analysis of cDNA generated by 5'RACE from CSF1R coding sequences identified a novel fusion of the RNA binding motif 6 (RBM6) gene to CSF1R gene generated presumably by a t(3;5)(p21;q33) translocation. Expression of the RBM6-CSF1R fusion protein conferred interleukin-3 (IL-3)-independent growth in BaF3 cells, and induces a myeloid proliferative disease (MPD) with features of megakaryoblastic leukemia in a murine transplant model. These findings identify a novel potential therapeutic target in leukemogenesis, and demonstrate the utility of phosphoproteomic strategies for discovery of tyrosine kinase alleles. Show less

Members of a subclass of hairy/Enhancer of split [E(spl)] homologs, called hesr genes, are structurally related to another subclass of hairy/E(spl) homologs, Hes genes, which play an important role in neural development. To characterize the roles of hesr genes in neural development, we used the retina as a model system. In situ hybridization analysis indicated that all hesr genes are expressed in the developing retina, but only hesr2 expression is associated spatially with gliogenesis. Each member was then misexpressed with retrovirus in the retinal explant cultures prepared from mouse embryos or neonates, which well mimic in vivo retinal development. Interestingly, hesr2 but not hesr1 or hesr3 promoted gliogenesis while inhibiting rod genesis without affecting cell proliferation or death, suggesting that the cells that normally differentiate into rods adopted the glial fate by misexpression of hesr2. The gliogenic activity of hesr2 was more profound when it was misexpressed postnatally than prenatally. In addition, double mutation of the neuronal determination genes Mash1 and Math3, which increases Müller glia at the expense of bipolar cells, upregulated hesr2 expression. These results indicate that, among structurally related hesr genes, only hesr2 promotes glial versus neuronal cell fate specification in the retina and that antagonistic regulation between hesr2 and Mash1-Math3 may determine the ratios of neurons and glia. Show less