Publications by authors named "K Matsumoto"

9,093 Publications

Extracellular vesicle-shuttled miRNAs as a diagnostic and prognostic biomarker and their potential roles in gallbladder cancer patients.

Sci Rep 2021 Jun 10;11(1):12298. Epub 2021 Jun 10.

Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science, Okayama, Japan.

Circulating microRNAs (miRNAs) in serum extracellular vesicles (EVs) are a promising biomarker in cancer. We aimed to elucidate the serum EVs miRNA biomarkers to identify patients with gallbladder cancer (GBC) and to clarify their potential roles. One hundred nineteen serum EVs from GBC and non-GBC individuals were isolated by pure-EVs-yieldable size-exclusion chromatography, and then were analyzed using a comprehensive miRNAs array and RT-qPCR-based validation. The functional roles of the identified miRNAs were also investigated using GBC cell lines. Serum EVs miR-1246 and miR-451a were significantly upregulated and downregulated, respectively in GBC patients (P = 0.005 and P = 0.001), in line with their expression levels in cancer tissue according to an in silico analysis. The combination of CEA and CA19-9 with miR-1246 showed the highest diagnostic power (AUC, 0.816; Sensitivity, 72.0%; Specificity, 90.8%), and miR-1246 was an independent prognostic marker of GBC (Hazard ratio, 3.05; P = 0.017) according to a Cox proportional hazards model. In vitro, miR-1246 promoted cell proliferation and invasion, while miR-451a inhibited cell proliferation and induced apoptosis with the targeting of MIF, PSMB8 and CDKN2D. Taken together, miR-1246 in serum EVs has potential application as a diagnostic and prognostic marker and miR-451a may be a novel therapeutic target in GBC.
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http://dx.doi.org/10.1038/s41598-021-91804-0DOI Listing
June 2021

Radiation-Induced Autophagy in Human Pancreatic Cancer Cells is Critically Dependent on G2 Checkpoint Activation: A Mechanism of Radioresistance in Pancreatic Cancer.

Int J Radiat Oncol Biol Phys 2021 May 25. Epub 2021 May 25.

Radiation and Cancer Biology Group. Electronic address:

Purpose: Autophagy and cell-cycle checkpoints act in concert to confer cellular radioresistance. We investigated the functional interaction between radiation-induced autophagy and G2 checkpoint activation in highly radioresistant human pancreatic ductal adenocarcinoma (PDAC) cells.

Methods And Materials: Four human PDAC cell lines (MIA PaCa-2, KP-4, Panc-1, and SUIT-2) were analyzed. These cells were first irradiated using x-rays, and their cell cycle status, autophagy, and cell cycle checkpoint marker expression and ATP production levels were evaluated. Autophagic flux assays and siRNA knockdown were used to evaluate autophagy activity. Double thymidine block experiments were performed to synchronize the cells. Two inhibitors (MK-1775 and SCH 900776) were used to attenuate G2 checkpoint activation. Cell survival assays and animal experiments were performed to evaluate the radiosensitizing effects of the G2 checkpoint inhibitors.

Results: Autophagy and G2/M accumulation were synchronously induced in human PDAC cells with an activated G2 checkpoint at 12 hours after x-ray irradiation of 6 Gy. Radiation-induced autophagy produced the ATP levels required for cell survival. Double thymidine block experiments revealed that no autophagy occurred in cells that were solely in G2 phase. MK-1775 or SCH 900776 exposure attenuated not only G2 checkpoint activation but also postirradiation autophagy, indicating the dependence of radiation-induced autophagy on an activated G2 checkpoint. The inhibitors demonstrated a higher radiosensitizing effect in the PDAC cells than the autophagy inhibitor chloroquine. MK-1775 in combination with x-rays significantly suppressed the tumor growth of MIA PaCa-2 xenografts compared with other treatment groups, including radiation or drug exposure alone, to enhance the radiosensitivity of PDAC cells in vivo.

Conclusions: Biological crosstalk exists between the G2 checkpoint activation and radiation-induced autophagy processes that are believed to independently contribute to the radioresistance of human PDAC cells. These findings have important implications for the development of future radiation therapy strategies for PDAC.
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http://dx.doi.org/10.1016/j.ijrobp.2021.04.001DOI Listing
May 2021

Therapeutic options for CTLA-4 Insufficiency.

J Allergy Clin Immunol 2021 Jun 7. Epub 2021 Jun 7.

The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.

Background: Heterozygous germline mutations in cytotoxic T-lymphocyte-associated antigen-4 (CTLA4) impair the immunomodulatory function of regulatory T cells. Affected individuals are prone to life-threatening autoimmune and lymphoproliferative complications. A number of therapeutic options are currently used with variable effectiveness.

Bjective: To characterize the responsiveness of patients with CTLA-4 insufficiency to specific therapies and provide recommendations for the diagnostic work-up and therapy at an organ-specific level.

Methods: Clinical features, laboratory findings, and response to treatment were reviewed retrospectively in an international cohort of 173 CTLA4 mutation carriers. Patients were followed between 2014 and 2020 for a total of 2,624 months from diagnosis. Clinical manifestations were grouped based on organ-specific involvement. Medication use and response were recorded and evaluated.

Results: Among the 173 CTLA4 mutation carriers, 123 (71%) had been treated for immune complications. Abatacept, rituximab, sirolimus, and corticosteroids ameliorated disease severity especially in case of cytopenias and lymphocytic organ-infiltration of the gut, lungs and central nervous system. Immunoglobulin replacement was effective in infection prevention. Only four (25%) of 16 patients with cytopenia who were splenectomized had a sustained clinical response. Cure was achieved with stem cell transplantation in 13 (72%) of 18 patients. As a result of the above, organ-specific treatment pathways were developed.

Conclusion: Systemic immunosuppressants and abatacept may provide partial control but require ongoing administration. Allogeneic hematopoietic stem cell transplantation offers a possible cure for patients with CTLA-4 insufficiency.

Clinical Impact: The benefits and risks of symptomatic and curative therapies need to be considered when deciding on the best treatment for patients with CTLA-4 insufficiency.
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http://dx.doi.org/10.1016/j.jaci.2021.04.039DOI Listing
June 2021

Metagenomic analysis of gut microbiota reveals its role in trimethylamine metabolism in heart failure.

Int J Cardiol 2021 Jun 5. Epub 2021 Jun 5.

Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.

Background: We had previously reported an increase in trimethylamine N-oxide (TMAO) levels in patients with both compensated and decompensated heart failure (HF) and alteration in gut microbiota composition using 16S rRNA gene amplicon analysis. Although a metagenome-wide analysis showed that choline-TMA lyase levels increased in HF patients, which TMA generation pathway from choline, carnitine, or betaine contributes to the increase in TMAO levels in HF needs to be elucidated.

Methods: We conducted a metagenome-wide shotgun sequencing analysis of gut microbiota and measured the TMAO levels in plasma of 22 HF patients during the compensated phase and 11 age-, sex-, and comorbidity-matched control subjects, whose gut microbiota compositions were reported in a previous 16S rRNA-based analysis.

Results: The abundance of cntA/B was positively correlated with TMAO, especially in HF patients, whereas that of cutC/D or betaine reductase was not correlated either in controls or HF patients. The abundance of cntA/B was mainly derived from the genera Escherichia and Klebsiella either in controls or HF patients.

Conclusion: TMAO levels in plasma depend on the abundance of cntA/B in HF. Although it is difficult to exclude the involvement of confounding factors, microbial dysbiosis connecting the abundance of cntA/B in the gut and the increase of TMAO in plasma can be a therapeutic target for HF.
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http://dx.doi.org/10.1016/j.ijcard.2021.06.003DOI Listing
June 2021

Refinement of decision tree to assess the consequences of increased serum ALP in dogs: Additional analysis on toxicity studies of pesticides evaluated recently in Japan.

Regul Toxicol Pharmacol 2021 Jun 5;124:104963. Epub 2021 Jun 5.

Tokyo University of Agriculture and Technology, Tokyo, Japan. Electronic address:

Recently we provided a new interpretation that increased serum ALP in dogs is not adverse if no hepatotoxic finding coexists in the analysis of toxicity studies of over 200 pesticides evaluated in Japan (Yokoyama et al., 2019). We also proposed a decision tree to evaluate the adversity of the increased ALP. The present analysis was conducted to validate the reliability of this interpretation with 129 pesticides more recently evaluated. Before applying, the decision tree was revised to be consistent in all steps. The pesticides showed similar characterization of increased ALP to the previous analysis in that the increase was more frequent than in rats and that liver hypertrophy and hepatotoxicity commonly coexisted with an increase in ALP in dogs. When short- and long-term studies of 58 pesticides inducing ALP activity in dogs were applied to the revised tree, the increased ALP in 8 pesticides was judged not adverse in either study. The revision of the tree did not affect the NOAEL judgment of these pesticides; however, the revised routes contributed to the judgment more robustly. This study showed the reliability of our interpretation and applicability of the decision tree to evaluate the adversity of increased ALP in dogs.
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http://dx.doi.org/10.1016/j.yrtph.2021.104963DOI Listing
June 2021