👤 Yutaka Muto

Gastrointestinal malignancies account for 25% of all cancer cases and 35% of cancer-related mortality. Next-generation sequencing (NGS) can elucidate the genomic landscape of gastrointestinal cancers; tissue-based genotyping has traditionally been used, but liquid biopsy-based genotyping is a noninvasive alternative. Moreover, geographical variations in the genomic landscape of gastrointestinal cancers have not been fully elucidated. This retrospective study aimed to gain insight into the genomic landscape of patients with gastrointestinal cancers from the Asia and Middle East (AME) region using plasma-derived circulating tumor DNA (ctDNA). From routine clinical practice, 2,601 plasma samples were collected from 2,062 patients with gastrointestinal cancers in the AME region. NGS profiling was conducted using the Guardant360® assay. The frequency of biomarkers that can aid decision-making in cancer patients was investigated. Single-nucleotide variants affected most commonly TP53 (70.4%), KRAS (44.0%), APC (25.7%), ATM (15.1%), and PIK3CA (12.3%). Copy number alterations were most often observed in EGFR (13.7%), CCNE1 (5.9%), PIK3CA (5.0%), MYC (4.7%), and FGFR1 (4.6%); fusions were detected in 1.6% of patients and most frequently affected FGFR2, RET, ALK, FGFR3, and NTRK1/3. In patients with pancreatic adenocarcinoma, the most frequently observed clinically informative genomic biomarkers occurred in KRAS (G12C, 1.6%; all others, 67.1%), BRCA1/2 (4.1%), BRAF (V600X, 1.5%), and microsatellite instability-high (MSI-H) (1.0%). In patients with colorectal cancer, the most common clinically relevant alterations were KRAS (49.0%), BRAF (V600E, 7.6%), and NRAS (5.7%) mutations; ERBB2 amplifications (2.5%); and MSI-H (1.8%). In patients with biliary tract cancers, actionable alterations included IDH1 mutations (11.1%), ERBB2 amplifications (4.6%), FGFR2 fusions (2.0%), MSI-H (2.0%), and BRAF V600E (1.5%). In patients with gastric or gastroesophageal junction adenocarcinomas, actionable alterations included ERBB2 amplifications (10.1%) and MSI-H (3.6%). Our data provide insight into the genomic landscape of patients with gastrointestinal cancers from the AME region using ctDNA analysis. These findings highlight the potential utility of liquid biopsy as a noninvasive tool for characterizing tumor genomic profiles and support its role in clinical practice. Show less

Fibroblast growth factor receptors (FGFRs) are a highly conserved family of transmembrane receptor tyrosine kinases with multiple roles in the regulation of key cellular processes. Specific FGFR mutations have been observed in several types of cancers, including gastric carcinoma and cholangiocarcinoma. Dose escalation data of 24 Japanese patients with solid tumors treated with Tasurgratinib (previously known as E7090), a potent, selective FGFR1-3 inhibitor, was reported in a phase I, first-in-human, single-center study. Based on the safety, pharmacokinetic, and pharmacodynamic profiles observed in this study, the recommended dose of 140 mg once daily was selected for the expansion part (Part 2), a multicenter expansion of the dose-finding study restricted to patients with tumors harboring FGFR gene alterations. Safety and preliminary efficacy were assessed in Part 2. Pharmacodynamic pharmacogenomic markers (serum phosphate, FGF23, and 1,25-(OH) Show less

Transient ischemic attack (TIA) is a predictor for cerebral infarction (CI), and early diagnosis of TIA is extremely important for the prevention of CI. We set out to identify novel antibody biomarkers for TIA and CI, and detected matrix metalloproteinase 1 (MMP1), chromobox homolog 1 (CBX1), and chromobox homolog 5 (CBX5) as candidate antigens using serological identification of antigens by recombinant cDNA expression cloning (SEREX) and Western blotting to confirm the presence of serum antibodies against the antigens. Amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) revealed that serum antibody levels were significantly higher in patients with TIA or acute-phase CI (aCI) compared with healthy donors ( Show less

To investigate whether high glucose (HG) induces mitochondrial dysfunction and promotes apoptosis in retinal Müller cells. Rat retinal Müller cells (rMC-1) grown in normal (N) or HG (30 mM glucose) medium for 7 days were subjected to MitoTracker Red staining to identify the mitochondrial network. Digital images of mitochondria were captured in live cells under confocal microscopy and analyzed for mitochondrial morphology changes based on form factor (FF) and aspect ratio (AR) values. Mitochondrial metabolic function was assessed by measuring oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) using a bioenergetic analyzer. Cells undergoing apoptosis were identified by differential dye staining and TUNEL assay, and cytochrome c levels were assessed by Western blot analysis. Cells grown in HG exhibited significantly increased mitochondrial fragmentation compared to those grown in N medium (FF = 1.7 ± 0.1 vs. 2.3 ± 0.1; AR = 2.1 ± 0.1 vs. 2.5 ± 0.2; P < 0.01). OCR and ECAR were significantly reduced in cells grown in HG medium compared to those grown in N medium (steady state: 75% ± 20% of control, P < 0.02; 64% ± 22% of control, P < 0.02, respectively). These cells also exhibited a significant increase (∼2-fold) in the number of apoptotic cells compared to those grown in N medium (P < 0.01), with a concomitant increase in cytochrome c levels (247% ± 94% of control, P < 0.05). Findings indicate that HG-induced mitochondrial morphology changes and subsequent mitochondrial dysfunction may contribute to retinal Müller cell loss associated with diabetic retinopathy. Show less

To investigate whether high glucose (HG) alters connexin 43 (Cx43) expression and gap junction intercellular communication (GJIC) activity in retinal Müller cells, and promotes Müller cell and pericyte loss. Retinal Müller cells (rMC-1) and cocultures of rMC-1 and retinal pericytes were grown in normal (N) or HG (30 mM glucose) medium. Additionally, rMC-1 transfected with Cx43 small interfering RNA (siRNA) were grown as cocultures with pericytes, and rMC-1 transfected with Cx43 plasmid were grown in HG. Expression of Cx43 was determined by Western blotting and immunostaining and GJIC was assessed by scrape-loading dye transfer (SLDT) technique. Apoptosis was analyzed by TUNEL or differential staining assay, and Akt activation by assessing Akt phosphorylation. In monocultures of rMC-1 and cocultures of rMC-1 and pericytes, Cx43 protein level, number of Cx43 plaques, GJIC, and Akt phosphorylation were significantly reduced in HG medium. Number of TUNEL-positive cells was also significantly increased in rMC-1 monocultures and in rMC-1 and pericyte cocultures grown in HG medium. Importantly, when rMC-1 transfected with Cx43 siRNA were grown as cocultures with pericytes, a significant decrease in GJIC, and increase in TUNEL-positive cells was observed, concomitant with decreased Akt phosphorylation. Upregulation of Cx43 rescued rMC-1 from HG-induced apoptosis. Gap junction communication between Müller cells and pericytes is essential for their survival. Downregulation of Cx43 that is HG induced and impairment of GJIC activity in Müller cells contributes to loss of glial and vascular cells associated with the pathogenesis of diabetic retinopathy. Show less

The spliceosomal U1C protein is critical to the initiation and regulation of precursor messenger RNA (pre-mRNA) splicing, as part of the U1 small nuclear ribonucleoprotein particle (snRNP). We have produced full-length and 61 residue constructs of human U1C in soluble form in Escherichia coli. Atomic absorption spectroscopy and mass spectrometry show that both constructs contain one Zn atom and are monomeric. Gelmobility-shift assays showed that one molecule of recombinant U1C, either full-length or 61 residue construct, can be incorporated into the U1 snRNP core domain in the presence of U1 70k. This result is in perfect agreement with the previous experiment with U1C isolated from the HeLa U1 snRNP showing that the recombinant U1C is functionally active. We have determined the solution structure of the N-terminal 61 residue construct of U1C by NMR. A Cys(2)His(2)-type zinc finger, distinct from the TFIIIA-type, is extended at its C terminus by two additional helices. The two Zn-coordinating histidine residues are separated by a five residue loop. The conserved basic residues in the first two helices and the intervening loop may be involved in RNA binding. The opposite beta-sheet face with two surface-exposed Tyr residues may be involved in protein contacts. Both the full-length and 61 residue constructs of human U1C fail to bind RNA containing the 5' splice site sequence, in contrast to what has been reported for the Saccharomyces cerevisiae orthologue. Show less