Sep. 2025, 日本癌学会, 日本癌学会奨励賞　　　　　　　　　　　　　　　
細胞外基質の硬さに着目したがん悪性化機構の解明
石原誠一郎

Sep. 2024, 第10回部局横断シンポジウム研究助成採択・金賞　　　　　　　　　　　　　　　
石原誠一郎;園下将大

Jan. 2024, がん関連三学会Rising Starネットワーキング, 優秀賞　　　　　　　　　　　　　　　
「硬さ」に応答したがん細胞が転写因子ATF5を介して悪性化するメカニズム
石原 誠一郎

Oct. 2023, 第9回部局横断シンポジウム研究助成採択・金賞　　　　　　　　　　　　　　　
石原誠一郎;園下将大

Sep. 2020, AMED NYAS, Interstellar Initiative Outstanding Team Presentation　　　　　　　　　　　　　　　
Interstellar Initiative
Seiichiro Ishihara;Simona Giunta;Hagar Labouta

Nov. 2019, 第5回北海道大学部局横断シンポジウム 口頭発表第1位　　　　　　　　　　　　　　　
膵臓がん細胞でメカニカルな刺激により活性化する転写因子ATF5
石原 誠一郎

Sep. 2019, 先端モデル動物支援プラットフォーム令和元年度若手支援技術講習会, ベストトーク賞　　　　　　　　　　　　　　　
転写因子ATF5から迫る膵がん細胞のメカノバイオロジー
石原 誠一郎

Sep. 2014, 平成26年度がん若手研究者ワークショップ, 優秀演者賞　　　　　　　　　　　　　　　
肺がん細胞において転写因子ATF5は放射線耐性・増殖能・浸潤能を上昇させる
石原 誠一郎

Oct. 2013, The American Society for Cell Biology 2013 Annual Meeting, Postdoc Travel Award　　　　　　　　　　　　　　　
Activating transcription factor 5 promotes radioresistance and invasiveness in lung adenocarcinoma cells
石原 誠一郎

Feb. 2010, The 6th HPAPS+(Special Edition), 若手優秀講演賞　　　　　　　　　　　　　　　
Cells settle down on a fluffy bed: a hard floor triggers emergency
石原 誠一郎

Down-regulation of proliferation-inhibiting factor EGR1 in brain metastatic cancer cells on a soft matrix.
Miki Omukai, Seiichiro Ishihara, Eishu Hirata, Hisashi Haga
Cell structure and function, 10 Feb. 2026, [Peer-reviewed], [Corresponding author], [Domestic magazines]
English, Scientific journal, Metastasis of cancer cells to the brain leads to a poor prognosis in patients with cancer. The brain environment is characterized by cell types, extracellular matrices (ECMs), and mechanical properties that differ from those of the primary tumors. A previous study using human melanoma cells (WM266.4 cells) and its highly brain-metastatic subline cells (WM266.4-BrM3 cells) revealed that WM266.4-BrM3 cells showed enhanced proliferation in brain tissues after cardiac injection in mice compared with WM266.4 cells. However, the effects of mechanical properties such as ECM stiffness on growth and gene expression in WM266.4-BrM3 cells remain to be clarified. In this study, we cultured these cells on ECMs of different stiffnesses. On a soft ECM, WM266.4-BrM3 cells showed significantly higher proliferation and lower expression of early growth response 1 (EGR1) and TP53 than WM266.4 cells. In contrast, on a stiff ECM, the proliferation and EGR1 expression of WM266.4 and WM266.4-BrM3 cells were not significantly different. Additionally, EGR1 knockdown by siRNA transfection in WM266.4 cells results in promoted cell proliferation and downregulated TP53 on a soft ECM. These results suggest that brain metastatic WM266.4 cells decrease EGR1 expression, thereby promoting cell proliferation via TP53 downregulation on a soft ECM.Key words: EGR1, ECM stiffness, metastasis, cancer, growth.

Protocol to culture cells on genipin-mixed collagen gels with different stiffnesses.
Seiichiro Ishihara, Hisashi Haga
STAR protocols, 6, 4, 104125, 104125, 01 Oct. 2025, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal, The stiffness of extracellular matrices is critical for cellular functions such as growth and differentiation. Here, we present a protocol for culturing cells on stiffness-modulated collagen gels by adding genipin, an amine crosslinker with low cytotoxicity. We describe the steps for preparing collagen gels with genipin, culturing the cells, and immunofluorescent staining of the cells on the gels. This protocol has potential applications in the analysis of function or protein/gene expression in cultured cells on extracellular matrices of different stiffnesses. For complete details on the use and execution of this protocol, please refer to Ishihara et al.1.

Genomic instability and shear stress influence quantum dot-induced endothelial cell responses and gene expression
Yasmin Abdelkader, Mahmoud Abdelkarim, Madhumita Suresh, Tulio J. Lopera, Simranpreet Dhaliwal, Shahla Shojaei, Lucas J. Pope, Qian Liu, Pingzhao Hu, Hisashi Haga, Kelsie L. Thu, Simona Giunta, Seiichiro Ishihara, Max Anikovskiy, Hagar I. Labouta
Materials Today Nano, 29, 100641, 100641, Elsevier BV, Aug. 2025, [Peer-reviewed]
Scientific journal

Stiff extracellular matrix activates the transcription factor ATF5 to promote the proliferation of cancer cells.
Seiichiro Ishihara, Atsushi Enomoto, Akihiro Sakai, Tadashi Iida, Shoichiro Tange, Noriyuki Kioka, Akihiro Nukuda, Ayaka Ichikawa Nagasato, Motoaki Yasuda, Takashi Tokino, Hisashi Haga
iScience, 28, 3, 112057, 112057, 21 Mar. 2025, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal, Cancer tissues are stiffer than normal tissues. Carcinogenesis stiffens the extracellular matrix (ECM) of cancerous tissues, to which cancer cells respond by activating transcription factors, such as YAP/TAZ, Twist1, and β-catenin, which further elevate their malignancy. However, these transcription factors are also expressed in normal tissues. Therefore, inhibiting these factors in order to treat cancer may lead to severe side effects. Here, we show that activating transcription factor 5 (ATF5), highly expressed in tumors, is activated by ECM stiffness and promotes the proliferation of cancer cells, including that of pancreatic cancer cells and lung cancer cells. In addition, ATF5 suppressed the expression of early growth response 1 (EGR1), thereby accelerating cancer cell proliferation. Stiff ECMs trigger the JAK-MYC pathway which activates ATF5. JAK activation was actomyosin independent whereas MYC induction was actomyosin dependent. These results demonstrate the critical role played by ATF5 in the mechanotransduction process seen in cancers.

Matrix stiffness regulates the triad communication of adipocytes/macrophages/endothelial cells through CXCL13.
Arthur Choisez, Seiichiro Ishihara, Takuro Ishii, Yidan Xu, Sepideh D Firouzjah, Hisashi Haga, Ryoichi Nagatomi, Joji Kusuyama
Journal of lipid research, 100620, 100620, 14 Aug. 2024, [Peer-reviewed], [International Magazine]
English, Scientific journal, Adipose tissue remodeling and plasticity are dynamically regulated by the coordinated functions of adipocytes, macrophages, and endothelial cells and extracellular matrix (ECM) that provides stiffness networks in adipose tissue component cells. Inflammation and fibrosis are crucial exogenous factors that dysregulate adipose tissue functions and drastically change the mechanical properties of the ECM. Therefore, communication among the ECM and adipose tissue component cells is necessary to understand the multifaceted functions of adipose tissues. To obtain in vivo stiffness, we utilized genipin as a crosslinker for collagen gels. Meanwhile, we isolated primary adipocytes, macrophages, and endothelial cells from C57BL/6J mice and incubated these cells in the differentiation media on temperature-responsive culture dishes. After the differentiation, these cell sheets were transferred onto genipin-crosslinked collagen gels with varying matrix stiffness. We found that inflammatory gene expressions were induced by hard matrix, whereas anti-inflammatory gene expressions were promoted by soft matrix in all three types of cells. Interestingly, the co-culture experiments of adipocytes, macrophages, and endothelial cells showed that the effects of soft or hard matrix stiffness stimulation on adipocytes were transmitted to the distant adipose tissue component cells, altering their gene expression profiles under normal matrix conditions. Finally, we identified that a hard matrix induces the secretion of CXCL13 from adipocytes, and CXCL13 is one of the important transmitters for stiffness communication with macrophages and endothelial cells. These findings provide insight into the mechano-transmission into distant cells and the application of stiffness control for chronic inflammation in adipose tissues with metabolic dysregulation.

The EGF/EGFR axis and its downstream signaling pathways regulate the motility and proliferation of cultured oral keratinocytes.
Ryota Kobayashi, Emi Hoshikawa, Taisuke Saito, Orakarn Suebsamarn, Eriko Naito, Ayako Suzuki, Seiichiro Ishihara, Hisashi Haga, Kei Tomihara, Kenji Izumi
FEBS open bio, 13, 8, 1469, 1484, Aug. 2023, [Peer-reviewed], [International Magazine]
English, Scientific journal, We previously reported that the cell and colony motion of oral keratinocytes are correlated with proliferative capacity, and speculated that this may be a specific index for monitoring cell quality. However, how cell motility and proliferation are regulated by signaling pathways remains unelucidated. Here, we found that the regulation of cell motility and proliferative capacity of oral keratinocytes can be attributed to the epidermal growth factor/epidermal growth factor receptor (EGF/EGFR) axis. The EGFR downstream cascade involving the Src/PI3K/Akt/mTOR signaling pathway showed a major effect on cell motility and proliferative capacity in oral keratinocytes. Furthermore, both EGFR and Src attenuated E-cadherin expression. Taken together, these findings provide a potential basis for future quality control of cells for therapeutic use.

Stiffness-Modulation of Collagen Gels by Genipin-Crosslinking for Cell Culture.
Seiichiro Ishihara, Haruna Kurosawa, Hisashi Haga
Gels (Basel, Switzerland), 9, 2, 10 Feb. 2023, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal, The stiffness of extracellular matrices (ECMs) is critical for cellular functions. Therefore, modulating the stiffness of ECMs in vitro is necessary to investigate the role of stiffness in cellular phenomena. Collagen gels are widely used for cell culture matrices in vitro. However, modulation of the stiffness in collagen gels for cell culture is challenging owing to the limited knowledge of the method to increase the stiffness while maintaining low cytotoxicity. Here, we established a novel method to modulate collagen gel stiffness from 0.0292 to 12.5 kPa with low cytotoxicity. We prepared collagens with genipin, a low-cytotoxic crosslinker of amines, at different concentrations and successfully modulated the stiffness of the gels. In addition, on 10 mM genipin-mixed collagen gels (approximately 12.5 kPa), H1299 human lung cancer cells showed spreading morphology and nuclear localization of yes-associated protein (YAP), typical phenomena of cells on stiff ECMs. Mouse mesenchymal stromal cells on 10 mM genipin-mixed collagen gels differentiated to vascular smooth muscle cells. On the other hand, the cells on 0 mM genipin-mixed collagen gels (approximately 0.0292 kPa) differentiated to visceral smooth muscle cells. Our new method provides a novel way to prepare stiffness-modulated collagen gels with low cytotoxicity in cell culture.

Substrate stiffness induces nuclear localization of myosin regulatory light chain to suppress apoptosis.
Katsuya Onishi, Seiichiro Ishihara, Masayuki Takahashi, Akihiro Sakai, Atsushi Enomoto, Kentaro Suzuki, Hisashi Haga
FEBS letters, 01 Feb. 2023, [Peer-reviewed], [International Magazine]
English, Scientific journal, Stiffness of the extracellular matrix regulates various biological responses, but the response mechanisms are poorly understood. Here, we found that the nuclear diphosphorylated myosin regulatory light chain (2P-MRLC) is a critical mechanomediator that suppresses apoptosis in response to substrate stiffness. Stiff substrates promoted the nuclear localization of 2P-MRLC. Zipper-interacting protein kinase [ZIPK; also known as death-associated protein kinase 3 (DAPK3)], a kinase for MRLC, was localized in the nucleus in response to stiff substrates and promoted the nuclear localization of 2P-MRLC. Moreover, actin fiber formation induced by substrate stiffness promoted the nuclear localization of 2P-MRLC via ZIPK. 2P-MRLC in response to substrate stiffness suppressed the expression of MAF bZIP transcription factor B (MafB) and repressed apoptosis. These findings reveal a newly identified role of MRLC in mechanotransduction.

The interferon-β/STAT1 axis drives the collective invasion of skin squamous cell carcinoma with sealed intercellular spaces
Yuji Kumagai, Junko Nio-Kobayashi, Seiichiro Ishihara, Atsushi Enomoto, Masashi Akiyama, Ryosuke Ichihara, Hisashi Haga
Oncogenesis, 11, 1, Springer Science and Business Media LLC, Dec. 2022, [Peer-reviewed]
Scientific journal, Abstract

The process by which cancer cells invade as a cell cluster, known as collective invasion, is associated with metastasis and worse prognosis of cancer patients; therefore, inhibition of collective invasion is considered to improve cancer treatment. However, the cellular characteristics responsible for collective invasion remain largely unknown. Here, we successfully established subclones with various invasive potentials derived from human skin squamous carcinoma cells. The cell cluster of the highly invasive subclone had a hermetically sealed and narrow intercellular space. Interferon-β was localized to the sealed intercellular spaces, leading to collective invasion via the activation of signal transducer and activator of transcription 1 (STAT1). On the other hand, interferon-β was not localized to non-sealed and wide intercellular spaces of the cell cluster of low-invasive subclone with deficient STAT1 activity. In the mixed cell cluster of high- and low-invasive subclones, the high-invasive sub-clonal cells were located at the invasive front of the invasive protrusion, leading to collective invasion by the low-invasive sub-clonal cells. Tissue microarray analysis of human skin squamous cell carcinoma (SCC) also showed enrichment of STAT1 in the invasive front of SCCs. These findings indicate that the intercellular structure controls the potential for collective invasion via STAT1 regulation in SCC.

Improvement of the cell viability of hepatocytes cultured in three-dimensional collagen gels using pump-free perfusion driven by water level difference.
Sumire Ishida-Ishihara, Ryota Takada, Kazuya Furusawa, Seiichiro Ishihara, Hisashi Haga
Scientific reports, 12, 1, 20269, 20269, 24 Nov. 2022, [Peer-reviewed], [Corresponding author], [International Magazine]
English, Scientific journal, Cell-containing collagen gels are one of the materials employed in tissue engineering and drug testing. A collagen gel is a useful three-dimensional (3D) scaffold that improves various cell functions compared to traditional two-dimensional plastic substrates. However, owing to poor nutrient availability, cells are not viable in thick collagen gels. Perfusion is an effective method for supplying nutrients to the gel. In this study, we maintained hepatocytes embedded in a 3D collagen gel using a simple pump-free perfusion cell culture system with ordinary cell culture products. Flow was generated by the difference in water level in the culture medium. Hepatocytes were found to be viable in a collagen gel of thickness 3.26 (± 0.16 S.E.)-mm for 3 days. In addition, hepatocytes had improved proliferation and gene expression related to liver function in a 3D collagen gel compared to a 2D culture dish. These findings indicate that our perfusion method is useful for investigating the cellular functions of 3D hydrogels.

Mammaglobin 1 mediates progression of trastuzumab-resistant breast cancer cells through regulation of cyclins and NF-κB.
Ratih Kusumastuti, Yuji Kumagai, Seiichiro Ishihara, Atsushi Enomoto, Takashi Murakami, Motoaki Yasuda, Hisashi Haga
FEBS open bio, 12, 10, 1797, 1813, 29 Jul. 2022, [Peer-reviewed], [International Magazine]
English, Scientific journal, Overexpression of human epidermal growth factor receptor 2 (HER2) in various cancers is correlated with poor patient survival. Trastuzumab, a recombinant humanized monoclonal antibody against HER2, has been considered to be a first-line therapy for HER2-positive breast cancer patients, but its usefulness is limited by the development of resistance. In this study, we established resistant cells by long-term treatment with trastuzumab. These cells showed higher proliferation, invasion, and migration abilities than the wild-type cells. Mammaglobin 1 (MGB1), cyclin D1, E1, A2, and phosphorylated NF-κB (p-p65) were upregulated in resistant cells. These proteins regulate cell proliferation, migration, and invasion of resistant cells. Depletion of MGB1 decreased cyclin and p-p65 expression. Cyclin D1 and A2, but not E1 expression, were affected by p-p65 downregulation. In summary, our results indicate that MGB1 expression is increased in breast cancer cells that have gained resistance to trastuzumab, and suggest that MGB1 promotes aggressiveness through cyclin and NF-κB regulation.

Vasculature atrophy causes a stiffened microenvironment that augments epidermal stem cell differentiation in aged skin
Ryo Ichijo, Koichiro Maki, Mio Kabata, Teruasa Murata, Arata Nagasaka, Seiichiro Ishihara, Hisashi Haga, Tetsuya Honda, Taiji Adachi, Takuya Yamamoto, Fumiko Toyoshima
Nature Aging, 2, 7, 592, 600, Springer Science and Business Media LLC, Jul. 2022, [Peer-reviewed]
Scientific journal

Correction: Pharmacologic conversion of cancer-associated fibroblasts from a protumor phenotype to an antitumor phenotype improves the sensitivity of pancreatic cancer to chemotherapeutics.
Tadashi Iida, Yasuyuki Mizutani, Nobutoshi Esaki, Suzanne M Ponik, Brian M Burkel, Liang Weng, Keiko Kuwata, Atsushi Masamune, Seiichiro Ishihara, Hisashi Haga, Kunio Kataoka, Shinji Mii, Yukihiro Shiraki, Takuya Ishikawa, Eizaburo Ohno, Hiroki Kawashima, Yoshiki Hirooka, Mitsuhiro Fujishiro, Masahide Takahashi, Atsushi Enomoto
Oncogene, 41, 23, 3302, 3302, 04 May 2022, [International Magazine]
English

Pharmacologic conversion of cancer-associated fibroblasts from a protumor phenotype to an antitumor phenotype improves the sensitivity of pancreatic cancer to chemotherapeutics.
Tadashi Iida, Yasuyuki Mizutani, Nobutoshi Esaki, Suzanne M Ponik, Brian M Burkel, Liang Weng, Keiko Kuwata, Atsushi Masamune, Seiichiro Ishihara, Hisashi Haga, Kunio Kataoka, Shinji Mii, Yukihiro Shiraki, Takuya Ishikawa, Eizaburo Ohno, Hiroki Kawashima, Yoshiki Hirooka, Mitsuhiro Fujishiro, Masahide Takahashi, Atsushi Enomoto
Oncogene, 41, 19, 2764, 2777, May 2022, [Peer-reviewed], [International Magazine]
English, Scientific journal, Previous therapeutic attempts to deplete cancer-associated fibroblasts (CAFs) or inhibit their proliferation in pancreatic ductal adenocarcinoma (PDAC) were not successful in mice or patients. Thus, CAFs may be tumor suppressive or heterogeneous, with distinct cancer-restraining and -promoting CAFs (rCAFs and pCAFs, respectively). Here, we showed that induced expression of the glycosylphosphatidylinositol-anchored protein Meflin, a rCAF-specific marker, in CAFs by genetic and pharmacological approaches improved the chemosensitivity of mouse PDAC. A chemical library screen identified Am80, a synthetic, nonnatural retinoid, as a reagent that effectively induced Meflin expression in CAFs. Am80 administration improved the sensitivity of PDAC to chemotherapeutics, accompanied by increases in tumor vessel area and intratumoral drug delivery. Mechanistically, Meflin was involved in the suppression of tissue stiffening by interacting with lysyl oxidase to inhibit its collagen crosslinking activity. These data suggested that modulation of CAF heterogeneity may represent a strategy for PDAC treatment.

Matrix Stiffness Contributes to Cancer Progression by Regulating Transcription Factors.
Seiichiro Ishihara, Hisashi Haga
Cancers, 14, 4, 18 Feb. 2022, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal, Matrix stiffness is critical for the progression of various types of cancers. In solid cancers such as mammary and pancreatic cancers, tumors often contain abnormally stiff tissues, mainly caused by stiff extracellular matrices due to accumulation, contraction, and crosslinking. Stiff extracellular matrices trigger mechanotransduction, the conversion of mechanical cues such as stiffness of the matrix to biochemical signaling in the cells, and as a result determine the cellular phenotypes of cancer and stromal cells in tumors. Transcription factors are key molecules for these processes, as they respond to matrix stiffness and are crucial for cellular behaviors. The Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) is one of the most studied transcription factors that is regulated by matrix stiffness. The YAP/TAZ are activated by a stiff matrix and promotes malignant phenotypes in cancer and stromal cells, including cancer-associated fibroblasts. In addition, other transcription factors such as β-catenin and nuclear factor kappa B (NF-κB) also play key roles in mechanotransduction in cancer tissues. In this review, the mechanisms of stiffening cancer tissues are introduced, and the transcription factors regulated by matrix stiffness in cancer and stromal cells and their roles in cancer progression are shown.

Soft surfaces promote astrocytic differentiation of mouse embryonic neural stem cells via dephosphorylation of MRLC in the absence of serum.
Hiroshi Oyama, Akihiro Nukuda, Seiichiro Ishihara, Hisashi Haga
Scientific reports, 11, 1, 19574, 19574, 01 Oct. 2021, [Peer-reviewed], [International Magazine]
English, Scientific journal, Astrocytes, which can be obtained from neural stem cells (NSCs) by adding serum and/or recombinant proteins in culture media or by passaging NSCs repeatedly, are expected to be applicable in regenerative medicine for the treatment of neurodegenerative diseases. However, astrocytes obtained using existing methods are costly and have poor quality. The stiffness of culture surfaces has been reported to affect astrocytic differentiation of adult NSCs. However, the influence of surface stiffness on astrocytic differentiation of embryonic NSCs has not yet been reported. In this study, we showed that astrocytic differentiation of embryonic NSCs was increased on soft surfaces (1 kPa and 12 kPa) compared with the NSCs on stiff surfaces (2.8 GPa) in serum-free condition. Furthermore, di-phosphorylated myosin regulatory light chain (PP-MRLC) was decreased in embryonic NSCs cultured on the soft surfaces than the cells on the stiff surfaces. Additionally, astrocytic differentiation of embryonic NSCs was induced by a Ras homolog associated kinase (ROCK) inhibitor, which decreased PP-MRLC in NSCs. These results suggest that decreasing the PP-MRLC of embryonic NSCs on soft surfaces or treating NSCs with a ROCK inhibitor is a good method to prepare astrocytes for application in regenerative medicine.

Osmotic gradient induces stable dome morphogenesis on extracellular matrix.
Sumire Ishida-Ishihara, Masakazu Akiyama, Kazuya Furusawa, Isao Naguro, Hiroki Ryuno, Takamichi Sushida, Seiichiro Ishihara, Hisashi Haga
Journal of cell science, 133, 14, 23 Jun. 2020, [Peer-reviewed], [International Magazine]
English, Scientific journal, One of the fundamental processes of morphogenesis is dome formation, but many parts of the mechanisms has been unexplored. Previous in vitro studies showed that osmotic gradient is the driving factor of the dome formation. However, these investigations were performed without extracellular matrix (ECM), which provides structural support to morphogenesis. With the use of ECM, we observed that basal hypertonic stress induced stable domes in vitro that have not been seen in previous studies. These domes developed from the ECM swelling via aquaporin water transport activity. Based on computer simulation, uneven swelling, with a positive feedback between extending cell and enhanced water transport, was a cause for dome formation. These results indicate that osmotic gradient induces dome morphogenesis via both enhanced water transport activity and subsequent ECM swelling.

Meflin-Positive Cancer-Associated Fibroblasts Inhibit Pancreatic Carcinogenesis.
Mizutani Y, Kobayashi H, Iida T, Asai N, Masamune A, Hara A, Esaki N, Ushida K, Mii S, Shiraki Y, Ando K, Weng L, Ishihara S, Ponik SM, Conklin MW, Haga H, Nagasaka A, Miyata T, Matsuyama M, Kobayashi T, Fujii T, Yamada S, Yamaguchi J, Wang T, Woods SL, Worthley D, Shimamura T, Fujishiro M, Hirooka Y, Enomoto A, Takahashi M
Cancer research, 79, 20, 5367, 5381, Oct. 2019, [Peer-reviewed], [International Magazine]
English, Scientific journal, Cancer-associated fibroblasts (CAF) constitute a major component of the tumor microenvironment. Recent observations in genetically engineered mouse models and clinical studies have suggested that there may exist at least two functionally different populations of CAFs, that is, cancer-promoting CAFs (pCAF) and cancer-restraining CAFs (rCAF). Although various pCAF markers have been identified, the identity of rCAFs remains unknown because of the lack of rCAF-specific marker(s). In this study, we found that Meflin, a glycosylphosphatidylinositol-anchored protein that is a marker of mesenchymal stromal/stem cells and maintains their undifferentiated state, is expressed by pancreatic stellate cells that are a source of CAFs in pancreatic ductal adenocarcinoma (PDAC). In situ hybridization analysis of 71 human PDAC tissues revealed that the infiltration of Meflin-positive CAFs correlated with favorable patient outcome. Consistent herewith, Meflin deficiency led to significant tumor progression with poorly differentiated histology in a PDAC mouse model. Similarly, genetic ablation of Meflin-positive CAFs resulted in poor differentiation of tumors in a syngeneic transplantation model. Conversely, delivery of a Meflin-expressing lentivirus into the tumor stroma or overexpression of Meflin in CAFs suppressed the growth of xenograft tumors. Lineage tracing revealed that Meflin-positive cells gave rise to α-smooth muscle actin-positive CAFs that are positive or negative for Meflin, suggesting a mechanism for generating CAF heterogeneity. Meflin deficiency or low expression resulted in straightened stromal collagen fibers, which represent a signature for aggressive tumors, in mouse or human PDAC tissues, respectively. Together, the data suggest that Meflin is a marker of rCAFs that suppress PDAC progression. SIGNIFICANCE: Meflin marks and functionally contributes to a subset of cancer-associated fibroblasts that exert antitumoral effects.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/20/5367/F1.large.jpg.

Modulation and Characterization of the Double Network Hydrogel Surface-Bulk Transition
Frauenlob Martin, King Daniel R, Guo Honglei, Ishihara Seiichiro, Tsuda Masumi, Kurokawa Takayuki, Haga Hisashi, Tanaka Shinya, Gong Jian Ping
MACROMOLECULES, 52, 17, 6704, 6713, 10 Sep. 2019, [Peer-reviewed]

The intercellular expression of type-XVII collagen, laminin-332, and integrin-β1 promote contact following during the collective invasion of a cancer cell population.
Kumagai Y, Nio-Kobayashi J, Ishida-Ishihara S, Tachibana H, Omori R, Enomoto A, Ishihara S, Haga H
Biochemical and biophysical research communications, 514, 4, 1115, 1121, Jul. 2019, [Peer-reviewed], [International Magazine]
English, Scientific journal, Cancer cells can invade as a population in various cancer tissues. This phenomenon is called collective invasion, which is associated with the metastatic potential and prognosis of cancer patients. The collectiveness of cancer cells is necessary for collective invasion. However, the mechanism underlying the generation of collectiveness by cancer cells is not well known. In this study, the phenomenon of contact following, where neighboring cells move in the same direction via intercellular adhesion, was investigated. An experimental system was created to observe the two-dimensional invasion using a collagen gel overlay to study contact following in collective invasion. The role of integrin-β1, one of the major extracellular matrix (ECM) receptors, in contact following was examined through the experimental system. Integrin-β1 was localized to the intercellular site in squamous carcinoma cells. Moreover, the intercellular adhesion and contact following were suppressed by treatment of an integrin-β1 inhibitory antibody. ECM proteins such as laminin-332 and type-XVII collagen were also localized to the intercellular site and critical for contact following. Collectively, it was demonstrated that the activity of integrin-β1 and expression of ECM proteins in the intercellular site promote contact following in the collective invasion of a cancer cell population.

Differential contributions of nonmuscle myosin IIA and IIB to cytokinesis in human immortalized fibroblasts.
Yamamoto K, Otomo K, Nemoto T, Ishihara S, Haga H, Nagasaki A, Murakami Y, Takahashi M
Experimental cell research, 376, 1, 67, 76, Mar. 2019, [Peer-reviewed]
English, Scientific journal

Glycosphingolipid GM2 Induces Invasiveness in Irradiation-tolerant Lung Cancer Cells.
Ishihara S, Aoki K, Mizutani T, Amano M, Nishimura SI, Haga H
Cell structure and function, 43, 2, 177, 185, 2018, [Peer-reviewed], [Lead author]

Mechano-Signal Transduction in Mesenchymal Stem Cells Induces Prosaposin Secretion to Drive the Proliferation of Breast Cancer Cells
Seiichiro Ishihara, David R. Inman, Wan-Ju Li, Suzanne M. Ponik, Patricia J. Keely
Cancer research, 77, 22, 6179, 6189, Nov. 2017, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

Mesenchymal stem cells in breast cancer: Response to chemical and mechanical stimuli
Seiichiro Ishihara, Suzanne M. Ponik, Hisashi Haga
Oncoscience, 4, 11-12, 158, 159, Impact Journals LLC, 2017, [Invited], [Lead author, Corresponding author]
English, Scientific journal

An improved method for western blotting when extracting proteins from mammalian cells cultured on a collagen gel under serum-free conditions
Seiichiro Ishihara, Takeomi Mizutani, Kazushige Kawabata, Hisashi Haga
Cytotechnology, 68, 1, 25, 32, Jan. 2016, [Peer-reviewed], [Lead author]
English, Scientific journal

Stiff substrates increase YAP-signaling-mediated matrix metalloproteinase-7 expression
A. Nukuda, C. Sasaki, S. Ishihara, T. Mizutani, K. Nakamura, T. Ayabe, K. Kawabata, H. Haga
Oncogenesis, 4, e165, Sep. 2015, [Peer-reviewed]
English, Scientific journal

ATF5: development of oncogenic resistance to radiotherapy
Seiichiro Ishihara, Hisashi Haga
Aging-US, 7, 7, 453, 454, Jul. 2015, [Invited], [Lead author]
English

Activating transcription factor 5 enhances radioresistance and malignancy in cancer cells
Seiichiro Ishihara, Motoaki Yasuda, Akihiro Ishizu, Masayori Ishikawa, Hiroki Shirato, Hisashi Haga
Oncotarget, 6, 7, 4602, 4614, Mar. 2015, [Peer-reviewed], [Lead author]
English, Scientific journal

Compressive Stress Induces Dephosphorylation of the Myosin Regulatory Light Chain via RhoA Phosphorylation by the Adenylyl Cyclase/Protein Kinase A Signaling Pathway
Kenji Takemoto, Seiichiro Ishihara, Takeomi Mizutai, Kazushige Kawabata, Hisashi Haga
PLOS ONE, 10, 3, e0117937, Mar. 2015, [Peer-reviewed]
English, Scientific journal

Filamin B Enhances the Invasiveness of Cancer Cells into 3D Collagen Matrices
Yuta Iguchi, Seiichiro Ishihara, Yoshimi Uchida, Kaori Tajima, Takeomi Mizutani, Kazushige Kawabata, Hisashi Haga
Cell structure and function, 40, 2, 61, 67, 2015, [Peer-reviewed]
English, Scientific journal

Coating extracellular matrix proteins on a (3-aminopropyl)triethoxysilane-treated glass substrate for improved cell culture
Hiro-taka Masuda, Seiichiro Ishihara, Ichiro Harada, Takeomi Mizutani, Masayori Ishikawa, Kazushige Kawabata, Hisashi Haga
Biotechniques, 56, 4, 172, 179, Apr. 2014, [Peer-reviewed]
English, Scientific journal

Substrate stiffness regulates temporary NF-kappa B activation via actomyosin contractions
Seiichiro Ishihara, Motoaki Yasuda, Ichiro Harada, Takeomi Mizutani, Kazushige Kawabata, Hisashi Haga
EXPERIMENTAL CELL RESEARCH, 319, 19, 2916, 2927, Nov. 2013, [Peer-reviewed], [Lead author]
English, Scientific journal

Lung Cancer Cells That Survive Ionizing Radiation Show Increased Integrin alpha 2 beta 1-and EGFR-Dependent Invasiveness
Xue Li, Seiichiro Ishihara, Motoaki Yasuda, Takeshi Nishioka, Takeomi Mizutani, Masayori Ishikawa, Kazushige Kawabata, Hiroki Shirato, Hisashi Haga
PLOS ONE, 8, 8, e70905, Aug. 2013, [Peer-reviewed]
English, Scientific journal

Irradiation-tolerant lung cancer cells acquire invasive ability dependent on dephosphorylation of the myosin regulatory light chain
Seiichiro Ishihara, Motoaki Yasuda, Takeshi Nishioka, Takeomi Mizutani, Kazushige Kawabata, Hiroki Shirato, Hisashi Haga
FEBS letters, 587, 6, 732, 736, Mar. 2013, [Peer-reviewed], [Lead author]
English, Scientific journal

Integrin beta 1-dependent invasive migration of irradiation-tolerant human lung adenocarcinoma cells in 3D collagen matrix
Seiichiro Ishihara, Hisashi Haga, Motoaki Yasuda, Takeomi Mizutani, Kazushige Kawabata, Hiroki Shirato, Takeshi Nishioka
Biochemical and biophysical research communications, 396, 3, 651, 655, Jun. 2010, [Peer-reviewed], [Lead author]
English, Scientific journal

Increased Motility and Invasiveness in Tumor Cells That Survive 10 Gy Irradiation
Kaori Tsutsumi, Masumi Tsuda, Natsuka Yazawa, Hirotaka Nakamura, Seiichiro Ishihara, Hisashi Haga, Motoaki Yasuda, Rie Yamazaki, Hiroki Shirato, Hideaki Kawaguchi, Takeshi Nishioka, Yusuke Ohba
Cell structure and function, 34, 2, 89, 96, 2009, [Peer-reviewed]
English, Scientific journal

組織の「硬さ」から迫る線維症研究の新展開　　　　　　　　　　　　　　　
石原 誠一郎, 芳賀 永, 実験医学増刊, 38, 12, 185, 190, Jul. 2020, [Invited], [Lead author]
Japanese, Introduction scientific journal

第2節 ハイドロゲル法　　　　　　　　　　　　　　　
石原 誠一郎, 芳賀 永, 三次元培養における培養手法と周辺技術動向, 23, 30, Apr. 2019, [Invited], [Lead author]
Japanese

硬い地面を掘り進む！がん硬化と集団浸潤　　　　　　　　　　　　　　　
石原 誠一郎, 実験医学, 36, 19, 3270, 3270, Dec. 2018, [Invited], [Lead author, Corresponding author]
Japanese, Book review

Activating transcription factor 5 promotes cancer cell invasion through transcriptional activation of integrins
A. Nukuda, H. Endoh, S. Ishihara, M. Yasuda, T. Mizutani, K. Kawabata, H. Haga, MOLECULAR BIOLOGY OF THE CELL, 26, 2015
English, Summary international conference

Lung cancer cells after irradiation indicate viability and malignancy dependent on activating transcription factor 5.
S. Ishihara, M. Yasuda, A. Ishizu, H. Haga, MOLECULAR BIOLOGY OF THE CELL, 25, Dec. 2014
English, Summary international conference

EGFR and Integrin alpha 2 beta 1 Dependent Invasiveness of Lung Adenocarcinoma Cells that Survived 10 Gy Ionizing Radiation.
X. Li, S. Ishihara, M. Yasuda, T. Mizutani, K. Kawabata, T. Nishioka, H. Haga, MOLECULAR BIOLOGY OF THE CELL, 23, 2012
English, Summary international conference

Substrate stiffness regulates NF-kB expression and activity in cancer cells
S. Ishihara, M. Yasuda, T. Mizutani, K. Kawabata, H. Haga, MOLECULAR BIOLOGY OF THE CELL, 22, 2011
English, Summary international conference

Increased Invasiveness and Non-spheroid Morphology Change of Human Lung Adenocarcinoma Cells That Survived 10 Gy Irradiation
T. Nishioka, S. Ishihara, Y. Miyai, T. Mizutani, K. Kawabata, H. Shirato, R. Yamazaki, M. Yasuda, H. Haga, K. Kawabata, INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS, 75, 3, S540, S540, 2009
English, Summary international conference

圧縮ストレスによるがん細胞の薬剤耐性獲得機構　　　　　　　　　　　　　　　
研究助成-がん領域-
Jan. 2026 - Dec. 2027
石原 誠一郎
MSD生命科学財団

硬さ応答性の転写因子ATF5によるがん細胞の悪性化メカニズム
科学研究費助成事業
01 Apr. 2024 - 31 Mar. 2027
石原 誠一郎
日本学術振興会, 基盤研究(C), 北海道大学, 24K10302

繊維化を介した膵臓がんの悪性化機構　　　　　　　　　　　　　　　
助成金
Apr. 2026 - Mar. 2027
石原 誠一郎
寿原記念財団

がん特異的なメカノレスポンス機構の解明とその創薬応用　　　　　　　　　　　　　　　
J-PEAKS連携研究プラットフォーム事業（インキュベーションステージ）
Apr. 2025 - Mar. 2027
北海道大学, 北海道大学, Principal investigator

Mechanobiology of metastasis
Grants-in-Aid for Scientific Research
Sep. 2023 - Mar. 2027
石原 誠一郎, 石井 琢郎, 石橋 公二朗, 丹下 正一朗
Japan Society for the Promotion of Science, Fund for the Promotion of Joint International Research (International Collaborative Research), Hokkaido University, Principal investigator, 23KK0143

細胞外基質の硬さ変化を指標とした多段階発がんの再定義
科学研究費助成事業
01 Apr. 2024 - 31 Mar. 2026
石原 誠一郎
日本学術振興会, 学術変革領域研究(A), 北海道大学, 24H01917

脳転移におけるメカノレスポンス機構の解明　　　　　　　　　　　　　　　
金沢大学 がん進展制御研究所 共同研究
Apr. 2024 - Mar. 2025

生体組織を模倣した新規の三次元細胞培養システム　　　　　　　　　　　　　　　
機械振興補助事業
Apr. 2023 - Mar. 2024
石原 誠一郎
公益財団法人JKA, Principal investigator

圧縮ストレスがトリガーとなるがん細胞の浸潤能獲得機構　　　　　　　　　　　　　　　
科学研究費補助金 基盤研究（C）
Apr. 2021 - Mar. 2024
石原 誠一郎
日本学術振興会, Principal investigator

メカノバイオロジーから迫るがん転移機構　　　　　　　　　　　　　　　
共同研究
Apr. 2020 - Mar. 2024
石原 誠一郎, 平田 英周
金沢大学 がん進展制御研究所, 北海道大学, Principal investigator

組織の硬さから迫るがんが転移しやすい臓器の共通性　　　　　　　　　　　　　　　
研究助成（奨励）
Jul. 2022 - Mar. 2023
石原 誠一郎
秋山記念生命科学振興財団, Principal investigator

足場材の硬さの違いを利用した上皮角化・非角化様式解明と培養口腔粘膜作成法への応用
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
Apr. 2020 - Mar. 2023
泉 健次, 芳賀 永, 石原 誠一郎, 加来 賢, 佐藤 大祐, 鈴木 絢子
今年度は、コロナの影響で魚うろこコラーゲンの入手がままならず、既製品の魚うろこコラーゲンであるセルキャンパスしか手に入らなかったため、コラーゲンゲルの足場材の硬さをランダムに変えての培養口腔粘膜作成はできなかった。その分、セルキャンパスを用いて、コントロールの硬い培養皿面、同表面でカルシウム濃度をあげた分化培地、および、いわゆるコラーゲンゲルの軟性面で培養したケラチノサイトに対し、運動能解析と外注によるマイクロアレイ解析による網羅的遺伝子発現分析（現在までに2サンプル解析終了し、現在もう2サンプル培養しており、外注予定）を実施し、結果がでたら新たに分担者に加わっていただいた凌先生にヒートマップとクラスター図を作成してもらい、ビッグデータ解析をお願いする。
細胞運動能解析では驚いたことに、コラーゲンゲル上の細胞運動能が、硬い培養皿面での細胞運動能より上回っていた。これは、いわゆる癌細胞のメカノバイオロジーと真逆の現象である。さらに、運動能が高いにも関わらず、ケラチノサイトの分化マーカー遺伝子発現が更新していることが示唆され、申請者の以前の基盤Ｂ研究で報告した結果とも相反するデータを得ており、今後考察を加え、メカニズム解明したい。また、コロナの影響で、研究分担者のいる北海道大学にＡＦＭを用いた細胞の硬さ検索ができなかった。
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Niigata University, Coinvestigator, 20H03870

Development of novel 3D cell culure system for the model of in vivo tissue　　　　　　　　　　　　　　　
研究成果展開事業 A-STEPトライアウトタイプ
May 2021 - Mar. 2022
石原 誠一郎
Japan Science and Technology Agency, 北海道大学, Principal investigator

Structural analysis of tumor hotspots, an epithelial tissue-intrinsic novel oncogenic niche
Grants-in-Aid for Scientific Research Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))
Oct. 2018 - Mar. 2022
Tamori Yoichiro
In the experimental studies using Drosophila wing imaginal epithelia as a model, we found that oncogenic mutant cells break the basement membrane and begin their invasive behavior into the stroma in microenvironments (invasion hotspots) scattered within the epithelial tissue. Analysis using the TCPD program (a program developed in this study to predict structural singularities in tissues) based on fluid analysis revealed that the locations detected as tissue confluence points (saddle points and sink points) in the tissues coincided with these invasion hotspots. These data indicate a novel idea that cancer cell invasion into the stroma starts from structural singularities intrinsic to epithelial tissues. Our experiments using a mouse model also showed that a similar phenomenon might be able to occur in mammalian tissues as well.
Japan Society for the Promotion of Science, Fund for the Promotion of Joint International Research (Fostering Joint International Research (B)), Hokkaido University, Coinvestigator, 18KK0234

臓器の硬さからアプローチするがん転移機構　　　　　　　　　　　　　　　
若手癌研究助成
Jan. 2021 - Dec. 2021
石原 誠一郎
安田記念医学財団, 北海道大学, Principal investigator

圧縮ストレスに引き起こされるがん細胞の浸潤能獲得　　　　　　　　　　　　　　　
研究奨励金
Mar. 2020 - Apr. 2021
石原 誠一郎
公益財団法人 上原記念生命科学財団, 北海道大学, Principal investigator

Targeted Nanotherapy for Rescuing Endothelial Dysfunction under Biomimetic Conditions of Atherosclerosis　　　　　　　　　　　　　　　
Interstellar Initiative
Oct. 2020 - Mar. 2021
石原 誠一郎, Hagar Labouta, Simona Giunta
NYAS/AMED, 北海道大学, Principal investigator

力学刺激に応答した膵臓がん細胞における遺伝子発現変動パターンの網羅解析　　　　　　　　　　　　　　　
次世代研究者リーダー育成共同研究助成
Sep. 2020 - Mar. 2021
石原 誠一郎, 丹下 正一朗
北海道大学, 北海道大学, Principal investigator

圧縮ストレスが誘導するがん細胞の浸潤能獲得機構　　　　　　　　　　　　　　　
研究助成金
Dec. 2019 - Mar. 2020
石原 誠一郎
公益財団法人 アステラス病態代謝研究会, 北海道大学, Principal investigator

腫瘍組織におけるがん細胞および間質細胞の硬さ応答機構を解明する　　　　　　　　　　　　　　　
リーダー育成プログラム支援
Sep. 2019 - Mar. 2020
石原 誠一郎, 榎本 篤
北海道大学, 北海道大学, Principal investigator

圧縮ストレスがもたらすMMP依存的ながん細胞の浸潤メカニズム　　　　　　　　　　　　　　　
札幌ライフサイエンス産業活性化事業 研究シーズ発掘補助金（札幌タレント補助金）
Jul. 2019 - Mar. 2020
石原 誠一郎
公益財団法人 北海道科学技術総合振興センター, 北海道大学, Principal investigator

Cancer metastasis regulated by tissue stiffness
Grants-in-Aid for Scientific Research Grant-in-Aid for Early-Career Scientists
Apr. 2018 - Mar. 2020
Ishihara Seiichiro
In this study, we investigated whether tissue stiffness is critical for metastasis of cancer cells. First, we prepared sheet of blood vessel endothelial cells on substrates with different stiffness. We also prepared collagen gels of different stiffness by treating with genipin, a cross-linker of collagen. We successfully made collagen gels with 0.02 to 10 kPa stiffness. Next, we performed live imaging to observe metastasis in vitro cell culture model. We observed the penetration of cancer cells in a sheet of blood vessel cells by using confocal laser scanning microscopy. We also found three genes up-regulated in blood vessel cells on stiff substrates.
Japan Society for the Promotion of Science, Grant-in-Aid for Early-Career Scientists, Hokkaido University, Principal investigator, 18K15232

3D morphogenesis of epithelial cell sheets in vitro
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
Jun. 2015 - Mar. 2020
Haga Hisashi
Three-dimensional morphogenesis of epithelial cells plays pivotal roles in many biological events as it is observed in embryogenesis. Mechanical properties of the extracellular substrate such as viscoelasticity and geometrical constraints are known as crucial factors that affect 3D morphogenesis of epithelial sheets. In this study, we found that epithelial cells (MDCK cells) cultured on a Matrigel crosslinked by Genipin exhibit dome formation by both the swelling of extracellular matrix and aquaporin water transport triggered by the basal hypertonic stress. Computer simulation was conducted and revealed that uneven swelling with a positive feedback between extending cell and enhanced water transport induces the dome formation. Moreover, we succeeded to establish a novel spherical substrate for cell culture by using a gelatin gel capsule. Human dermal fibroblasts cultured on the gel capsule made wrinkle-like structures on the spherical substrate, mimicking the early embryogenesis.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Hokkaido University, Coinvestigator, 15H05858

硬さ依存的に活性化する新規がん促進性転写因子の同定と機能解析　　　　　　　　　　　　　　　
第30回SGHがん研究助成
Dec. 2018 - Nov. 2019
石原 誠一郎
公益財団法人 SGH財団, 北海道大学, Principal investigator

組織の硬さに応答した間葉系幹細胞が引き起こすがん悪性化　　　　　　　　　　　　　　　
海外特別研究員
Apr. 2018 - Sep. 2019
石原 誠一郎
日本学術振興会, University of Wisconsin-Madison, Principal investigator

間葉系幹細胞のメカノレスポンスにより引き起こされるがん悪性化機構　　　　　　　　　　　　　　　
長期研究助成
Apr. 2017 - Mar. 2018
石原 誠一郎
公益財団法人 東洋紡バイオテクノロジー研究財団, University of Wisconsin-Madison, Principal investigator

放射線治療後に肺がんが再発し悪性化する機構の解明
Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
Apr. 2014 - Mar. 2015
石原 誠一郎
本研究は当初の計画よりも順調に進められた。本研究では、放射線治療後に肺がんが悪性化する機構の解明を目指した。特に、転写因子Activating transcription factor 5（ATF5）に着目し、この分子が肺がん細胞の放射線耐性・悪性度亢進に寄与するかどうかを調べた。そして主に以下の点を明らかにした。（１）ATF5は肺がん細胞の放射線耐性を増強させる。（２）肺がん細胞におけるATF5の発現および放射線耐性は、細胞周期のG1後期～S期で上昇する。（３）放射線照射後に生き残った肺がん細胞は、ATF5を高発現させる。（４）ATF5は、肺がん細胞の増殖能を亢進させる。（５）ATF5は、肺がん細胞の浸潤能を増強させる。（６）ATF5は、細胞‐基質間接着および細胞内張力を介して肺がん細胞の浸潤能を制御する。上記の通り、ATF5は肺がん細胞の放射線耐性および悪性度を上昇させることが明らかになった。これらの結果は、ATF5の阻害と放射線治療の併用が、肺がん治療に有効であることを示唆するものである。
我々は本研究の成果を学術論文として発表した（Ishihara et al., Oncotarget, 6, 4602-4614）。この論文はOncotarget誌のPriority Research Paperとして大きく紹介された。さらに、本研究の成果は4回の国際・国内学会等で発表された。特に、「平成26年度がん若手研究者ワークショップ」（2014年9月3日～9月6日、長野・蓼科温泉）では、「優秀演者賞」を受賞した。また、「がん研究分野の特性等を踏まえた支援活動公開シンポジウム」においても発表した。
以上の通り、本研究を順調に進めることができ、その成果を発表することができた。
Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (B), Hokkaido University, Principal investigator, 26860964

がん細胞におけるメカノセンシング機構の解明
Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows
2011 - 2012
石原 誠一郎
細胞は基質の硬さを感知し、それに応答して表現型を変化させることが知られている(メカノセンス)。しかし、メカノセンスの詳細なメカニズムは未だ不明である。メカノセンスでは、細胞骨格や細胞接着にかかわる分子が重要な働きをしていることがこれまでの研究で明らかになっている。しかし、基質の硬さと転写因子の関与についてはこれまでほとんど報告されていない。そこで、本研究では炎症反応に深く関与する転写因子NF-kBに着目し、基質の硬さがNF-kBに与える影響を調べた。今年度は、ヒト肺がん細胞H1299において、基質の硬さが転写因子NF-kBにどのような影響を与えるかを調べた。本研究により、(1)硬い基質上のH1299細胞は軟らかい基質上の細胞に比べて高いNF-kBの活性を示すこと、(2)NF-kBの活性化は、H1299細胞において炎症反応を引き起こすこと、(3)硬い基質はミオシン調節軽鎖のリン酸化を亢進させ、それがNF-kBの活性化を誘導すること、(4)転写因子NF-kBの活性化により、H1299細胞は浸潤性の形態を示すことが明らかになった。本研究結果により、硬い基質はがん細胞においてNF-kBの活性化とそれによる炎症反応を引き起こし、ひいてはがんの悪性化をもたらすことが示唆された。本結果をもとに、1回の国際セミナー(2013年1月、シンガポール)と1回の国内学会(2012年9月、札幌)で講演を行った。現在は本研究結果をまとめて、原著論文として投稿準備中である。
Japan Society for the Promotion of Science, Grant-in-Aid for JSPS Fellows, Hokkaido University, Principal investigator, 11J06280

科学の芽を育む実験教室　　　　　　　　　　　　　　　
北大元気プロジェクト
2006 - 2007
北海道大学