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Affiliation |
Faculty of Medicine School of Medicine Department of Medical Sciences, Pharmacology |
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Assistant Professor |
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Related SDGs |
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SEKIHARA Kazumasa
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Degree 【 display / non-display 】
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博士(医学) ( 2014.3 島根大学 )
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修士（医科学） ( 2009.3 北海道大学 )
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学士（保健学） ( 2007.3 徳島大学 )
Research Areas 【 display / non-display 】
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Life Science / Radiological sciences
Papers 【 display / non-display 】
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Preβ1-HDL binds to TG-rich lipoproteins and its release is impaired in the postprandial state among patients with poorly controlled type 2 diabetes. Reviewed International journal
Yuna Horiuchi, Satoshi Hirayama, Atsushi Hori, Yuri Ichikawa, Satoshi Soda, Utako Seino, Kazumasa Sekihara, Tsuyoshi Ueno, Yoshifumi Fukushima, Katsuo Kubono, Takashi Miida
Annals of clinical biochemistry 45632251328154 - 45632251328154 2025.3
Language：English Publishing type：Research paper (scientific journal)
BACKGROUND: Although preβ1-high-density lipoprotein (preβ1-HDL) promotes cholesterol efflux, high fasting preβ1-HDL levels after breakfast are reduced in patients with poorly controlled type 2 diabetes. OBJECTIVE: This study investigated whether preβ1-HDL binds to triglyceride (TG)-rich lipoproteins (TGRLs) in the postprandial state and is released during lipolysis. METHODS: We measured preβ1-HDL concentrations, lecithin-cholesterol acyltransferase (LCAT) activity, and LCAT-dependent preβ1-HDL conversion before and after breakfast in patients with diabetes. We also performed in vitro studies using TGRLs. Preβ1-HDL was quantified by enzyme-linked immunosorbent assay and native two-dimensional gradient gel (N-2D-gel) electrophoresis. RESULTS: Before breakfast, the diabetes group had higher preβ1-HDL concentrations than the healthy controls; after breakfast, levels in the two groups were similar. Neither LCAT mass nor the LCAT-dependent preβ1-HDL conversion rate changed after breakfast. Mixing of fasting plasma with chylomicrons or very-low-density lipoprotein (VLDL) reduced the preβ1-HDL level by 15% ± 4% and 45% ± 10%, respectively. N-2D-gel electrophoresis showed that preβ1-HDL was generated by bacteria-derived TG lipase only from postprandial VLDL of patients with type 2 diabetes. CONCLUSION: Preβ1-HDL binds to TGRLs in the postprandial state and is released during lipolysis, implying that postprandial hyperlipidemia impairs reverse cholesterol transport in patients with poorly controlled type 2 diabetes.
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Recent Trends and Potential of Radiotherapy in the Treatment of Anaplastic Thyroid Cancer. Reviewed International journal
Kazumasa Sekihara, Hidetomo Himuro, Soji Toda, Nao Saito, Ryoichi Hirayama, Nobuyasu Suganuma, Tetsuro Sasada, Daisuke Hoshino
Biomedicines 12 ( 6 ) 2024.6
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
Anaplastic thyroid cancer (ATC) is a rare but highly aggressive malignancy characterized by advanced disease at diagnosis and a poor prognosis. Despite multimodal therapeutic approaches that include surgery, radiotherapy, and chemotherapy, an optimal treatment strategy remains elusive. Current developments in targeted therapies and immunotherapy offer promising avenues for improved outcomes, particularly for BRAF-mutant patients. However, challenges remain regarding overcoming drug resistance and developing effective treatments for BRAF-wild-type tumors. This comprehensive review examines the clinical and biological features of ATC, outlines the current standards of care, and discusses recent developments with a focus on the evolving role of radiotherapy. Moreover, it emphasizes the necessity of a multidisciplinary approach and highlights the urgent need for further research to better understand ATC pathogenesis and identify new therapeutic targets. Collaborative efforts, including large-scale clinical trials, are essential for translating these findings into improved patient outcomes.
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Low serum carnitine level is associated with increased urinary carnitine excretion in late pregnancy. Reviewed International journal
Yutaro Kobori, Satoshi Hirayama, Yoshifumi Fukushima, Tsuyoshi Ueno, Kazumasa Sekihara, Atsushi Hori, Yuna Horiuchi, Shintaro Makino, Emiko Nishioka, Takashi Miida
Annals of clinical biochemistry 45632241239806 - 45632241239806 2024.3
Language：English Publishing type：Research paper (scientific journal)
BACKGROUND: Carnitine is essential for fatty acid metabolism. Free carnitine (FCA) is excreted in the urine in the glomerulus, but is partly reabsorbed by a carnitine transporter. The mechanism underlying the decrease in serum carnitine level during pregnancy is unclear. OBJECTIVE: To investigate whether low carnitine level is associated with increased renal excretion in pregnant women. METHODS: We recruited 43 healthy pregnant and 25 non-pregnant women. Total carnitine (TCA) and FCA levels were measured using the enzymatic cycling method, and the acylcarnitine (ACA) level was calculated. Fractional excretion (FE) was calculated as carnitine clearance divided by creatinine clearance. RESULTS: The mean TCA, FCA, and ACA levels were lower at 12 weeks of gestation in pregnant than non-pregnant women (p < 0.001); the levels decreased further at 36 weeks, reaching 39%, 36%, and 52% of those in non-pregnant women, respectively (p < 0.001). The FEs were 3-4-fold higher in pregnant women than non-pregnant women. Pregnant women had a lower serum FCA/TCA ratio than non-pregnant women (0.830 ± 0.074 vs. 0.788 ± 0.098, respectively; p < 0.05), whereas the urine FCA/TCA ratio was similar between the groups. CONCLUSION: Low carnitine level is associated with increased renal excretion during late pregnancy.
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SRPKIN-1 as an inhibitor against hepatitis B virus blocking the viral particle formation and the early step of the viral infection. Reviewed International journal
Xiaofang Li, Kenji Nakashima, Masahiko Ito, Mami Matsuda, Takeshi Chida, Kazumasa Sekihara, Hirotaka Takahashi, Takanobu Kato, Tatsuya Sawasaki, Tetsuro Suzuki
Antiviral research 220 105756 - 105756 2023.11
Language：English Publishing type：Research paper (scientific journal)
New antiviral agents are needed for the treatment of hepatitis B virus (HBV) infection because currently available drugs do not completely eradicate chronic HBV in patients. Phosphorylation dynamics of the HBV core protein (HBc) regulate several processes in the HBV life cycle, including nucleocapsid formation, cell trafficking, and virus uncoating after entry. In this study, the SRPK inhibitors SPHINX31, SRPIN340, and SRPKIN-1 showed concentration-dependent anti-HBV activity. Detailed analysis of the effects of SRPKIN-1, which exhibited the strongest inhibitory activity, on the HBV replication process showed that it inhibits the formation of infectious particles by inhibiting pregenomic RNA packaging into capsids and nucleocapsid envelopment. Mass spectrometry analysis combined with cell-free translation system experiments revealed that hyperphosphorylation of the C-terminal domain of HBc is inhibited by SRPKIN-1. Further, SRPKIN-1 exhibited concentration-dependent inhibition of HBV infection not only in HepG2-hNTCP-C4 cells but also in fresh human hepatocytes (PXB cells) and in the single-round infection system. Treatment with SRPKIN-1 at the time of infection reduced the nuclease sensitivity of HBV DNA in the nuclear fraction. These results suggest that SRPKIN-1 has the potential to not only inhibit the HBV particle formation process but also impair the early stages of viral infection.
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Validation of EZH2 Inhibitor Efficiency in Anaplastic Thyroid Carcinoma Cell Lines. Reviewed International journal
Hirotaka Nakayama, Nao Saito, Rika Kasajima, Nobuyasu Suganuma, Yasushi Rino, Katsuhiko Masudo, Haruhiko Yamazaki, Soji Toda, Kazumasa Sekihara, Hiroyuki Iwasaki, Daisuke Hoshino
Anticancer research 43 ( 3 ) 1073 - 1077 2023.3
Language：English Publishing type：Research paper (scientific journal)
BACKGROUND/AIM: The prognosis of anaplastic thyroid carcinoma (ATC) is poor, and there is currently no established treatment to improve its outcome. We previously reported that enhancer of zeste homolog 2 (EZH2) was highly expressed in ATC, and may be a therapeutic target; however, the effects of EZH2 on ATC growth currently remain unknown. MATERIALS AND METHODS: We investigated the effects of an EZH2 inhibitor (DZNep) on four ATC cell lines (8305C, KTA1, TTA1 and TTA2). We performed a gene panel analysis of all ATC cell lines to identify differences in DZNep sensitivity between the cell lines. To investigate the effects of DZNep on the recovery of differentiation, we assessed changes in thyroid differentiation markers (TDMs) before and after the DZNep treatment using PCR. RESULTS: EZH2 was expressed in all ATC cell lines. The cell-reducing effects of DZNep were detected in all ATC cell lines, and were the strongest in KTA1 cells followed by TTA2 cells. The TTA1 and 8305C cell lines, which showed weak cell-reducing effects, had TP53 mutations. No changes in TDMs were observed in any ATC cell line. CONCLUSION: DZNep, an EZH2 inhibitor, exerted suppressive effects on the growth of ATC cell lines and has potential as a therapeutic strategy; however, its effects may be attenuated in ATC with TP53 mutations.
MISC 【 display / non-display 】
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放射線単独および分子標的薬との併用療法は甲状腺未分化がん細胞を効果的に殺傷する(Radiation alone and in combination with molecularly targeted agents effectively kill anaplastic thyroid cancer cells) Reviewed
関原 和正, 氷室 秀知, 笹田 哲朗, 星野 大輔, 星野 大輔
日本癌学会総会記事 83回 J - 3051 2024.9
Language：English Publishing type：Rapid communication, short report, research note, etc. (scientific journal) Publisher：(一社)日本癌学会
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p53経路を活性化させる核小体ストレス応答を利用した新たながん治療薬 Reviewed
安木千央, 有馬一成, 山下恵汰, 山下恵汰, 下川倫子, 川畑拓斗, 関原和正, 古川龍彦, 河原康一
日本分子生物学会年会プログラム・要旨集(Web) 47th 2024
Publishing type：Rapid communication, short report, research note, etc. (scientific journal)
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CIRT Inhibits the Proliferation and Migration of Anaplastic Thyroid Carcinoma Cells Reviewed
関原和正, 氷室秀知, 平山亮一, 笹田哲朗, 星野大輔
日本がん転移学会学術集会・総会プログラム抄録集 33rd 2024
Publishing type：Rapid communication, short report, research note, etc. (scientific journal)
Presentations 【 display / non-display 】
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甲状腺未分化がん細胞における放射線と分子標的薬の併用効果
関原和正, 氷室秀知, 平山亮一, 笹田哲朗, 武谷立, 星野大輔
日本放射線腫瘍学会第38回学術大会
Event date： 2025.11.27 - 2025.11.29
Presentation type：Poster presentation
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腸内細菌叢と重粒子線の抗腫瘍効果との関連についての前臨床モデルを用いた検討
氷室秀知, 関原和正, 平山亮一, 紅露拓, 魏菲菲, 辻嘉代子, 星野大輔, 笹田哲朗
日本放射線腫瘍学会第38回学術大会
Event date： 2025.11.27 - 2025.11.29
Presentation type：Poster presentation
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Generation and characterization of Hemagglutinin-tagged FHOD3 knock-in mice.
Eka Adip Pradipta, Yohko Kage, Shalihah Shafiyyah Maratush, Kazumasa Sekihara, Ayako Miura, Ryu Takeya
第78回日本薬理学会西南部会
Event date： 2025.11.8
Presentation type：Oral presentation (general)
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Localization pattern of the formin protein FHOD3 in cardiomyocytes and its relationship to gain of function
Event date： 2025.11.3 - 2025.11.5
Presentation type：Poster presentation
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Carbon Ion Radiotherapy as a Promising Modality for Anaplastic Thyroid Carcinoma Treatment
Kazumasa Sekihara, Hidetomo Himuro, Ryoichi Hirayama, Tetsuro Sasada, Ryu Takeya, Daisuke Hoshino
The 68th Annual Meeting of the Japanese Radiation Research Society and The 6th Asian Congress of Radiation Research
Event date： 2025.10.23 - 2025.10.26
Presentation type：Poster presentation
Awards 【 display / non-display 】
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2024年度日本放射線影響学会奨励賞
2024.9 日本放射線影響学会
関原和正
Award type：Award from Japanese society, conference, symposium, etc.
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第3回JASTRO海外研修助成
2025.8 日本放射線腫瘍学会
関原和正
Award type：International academic award (Japan or overseas)
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ICRR2023 Travel Award
2023.8 日本放射線影響学会
関原和正
Award type：Award from Japanese society, conference, symposium, etc.
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ACRR2017 Travel Award
2017.8 日本放射線影響学会
関原和正
Award type：Award from Japanese society, conference, symposium, etc.
Grant-in-Aid for Scientific Research 【 display / non-display 】
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従来法とオルガノイド培養法の重粒子線による生物効果解析
Grant number：23K07100 2023.04 - 2026.03
日本学術振興会 科学研究費基金 基盤研究(C)
関原和正、平山亮一、氷室秀知
Authorship：Principal investigator
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放射線耐性を導く口腔がん幹細胞におけるSIRT6の役割
Grant number：19K19206 2019.04 - 2022.03
日本学術振興会 科学研究費補助金 若手研究
関原和正
Authorship：Principal investigator
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がん放射線治療の基礎となるPLDR阻害と修復不能なDNA二重鎖切断の関わり
Grant number：16K19855 2016.04 - 2020.03
日本学術振興会 科学研究費補助金 若手研究(B)
関原和正
Authorship：Principal investigator
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CXCL2依存性の腸脳相関を介した放射線治療効果増感についての検討
Grant number：23K07125 2023.04 - 2026.03
独立行政法人日本学術振興会 科学研究費基金 基盤研究(C)
氷室秀知、関原和正、平山亮一
Authorship：Coinvestigator(s)