• A proposed linkage of cancer metabolism and epigenetic alterations (Proc. Natl. Acad. Sci. USA, 111, 15526, 2014)

    In collaboration with the Department of Surgery, Osaka University (Profs. Masaki Mori and Yuichiro Doki), Hamabe et al. showed that pyruvate kinase M2 (PKM2), an alternatively spliced variant of the pyruvate kinase gene, mediates epithelial?mesenchymal transition (EMT), which is critical for aggressive cancer phenotypes. The study demonstrates that EMT stimulates nuclear translocation of PKM2 and controls transcription mechanism. The present study shows a role of pyruvate kinase M2 in transcriptional regulation leading to EMT. The precise understanding of nuclear PKM2 function suggests the potential for a model preventing metastasis of colorectal cancer.

  • Cancer stem cells of the gastrointestinal system (Review: JJCO, 44, 1141, 2014)

    In collaboration with the Department of Surgery, Osaka University, Colvin et al. update the recent advances in the understanding of cancer stem cell biology in the gastrointestinal system. This review underscores the aspects of  identification, origin, cell-cycle dormancy, relationship with epithelial-mesenchymal transition, cellular metabolism and the underlying molecular mechanisms.

  • Visualization and characterization of cancer stem-like cells in cervical cancer (Int J Oncol, 45, 2468, 2014)

    In the collaboration with the Department of Radiation Oncology, Osaka University, Hayashi , et al. investigated optical imaging parameters to evaluate cancer stem cells using human cervical cancer cells. The results of a sphere-forming assay revealed that the self-renewal ability of the population was significantly high. A tumorigenicity assay confirmed the tumorigenic potential. The radioresistance and chemoresistance were confirmed. These results indicate cancer stem cell-like properties and therapeutic resistance. Thus we successfully visualized cancer stem cell-like cells using this system.

  • Identification of chemoradiation-resistant osteosarcoma stem cells using an imaging system (Int J Oncol, 45, 2349, 2014)

    In the collaboration with the Department of Radiation Oncology, Osaka University, Tamari, et al. identified a subpopulation of cells with stem cell-like characteristics, such as tumor-initiating cells (TICs), which maintain the capacity to regenerate entire tumors. The study separated the osteosarcoma cells using the fluorescence-activated cell sorting (FACS)-based system and verified TIC-like properties. The present study demonstrated that chemoradiation-resistant cancer stem cells can be visualized by this system and suggested the rationale for further study of osteosarcoma stem cells.

  • Insulinoma medium induces the differentiation of mesenchymal cells into insulin-producing β-like cells (J Stem Cell Res Ther, 4, 1000221, 2014)

    In the collaboration of the Research Institute, National Center for Global Health and Medicine, Kawamoto et al. demonstrated that m urine insulinoma cell conditioned medium with ΒETA2 (NeuroD1) transduction efficiently induces the differentiation of adipose-derived mesenchymal stem cells (ADSC) into insulin-producing β-like cells both in vitro and in vivo. ΒETA2 is a member of the basic helix-loop-helix transcription factor family. These results suggest that the balance of the cytokines and growth factors in addition of gene manipulation would be beneficial for efficient differentiation of ADSCs into pancreatic β cells. Our technology could provide a path to β cell differentiation and novel cell replacement-based therapies for diabetes.

  • Identification of microRNA associated with chemoresistance and stemness in pancreatic cancer (Br. J Cancer, 111, 1572, 2014)

    Pancreatic cancer has a poor prognosis because of its high refractoriness to chemotherapy and tumor recurrence, and these properties have been attributed to cancer stem cells (CSCs). MicroRNA (miRNA) regulates various molecular mechanisms of cancer progression associated with CSCs. This study aimed to identify the candidate miRNA and to characterize the clinical significance. In collaboration with Osaka University and Tokyo University, Hasegawa et al. established chemo-resistant pancreatic cancer cells, and induced CSC-like properties through sphere formation. Candidate miRNAs were selected through microarray analysis. The overexpression and knockdown experiments were performed by evaluating the in vitro cell growth and in vivo tumorigenicity. The expression was studied in pancreatic cancer samples after laser captured microdissection and by immunohistochemical staining. The in vitro drug sensitivity of pancreatic cancer cells was altered according to the miR expression via a target. In vivo, we found that the miR could increase tumor-initiating potential and induced drug resistance. A high expression level of miR was correlated with a worse prognosis and the target expression was significantly lower in those patients.The data indicated that the miR expression was associated with chemoresistance and CSC-like properties via a target pathway, and could predict worse prognosis in pancreatic cancer patients. Detailed information will be available in publication.

  • Oxidative phosphorylation in colorectal cancer: roles of hexokinase 2 and phosphorylated pyruvate dehydrogenase-E1α in invasive front lesions (Cancer Science , 105, 1100-1108, 2014)

    Although numerous studies have shown the significance of cancer-specific aerobic glycolysis, how glycolysis contributes to tumor invasion, a critical phenomenon in metastasis, remains unclear. In collaboration with the Department of Surgery, Osaka University, Hamabe et al. studied two critical gate enzymes, hexokinase 2 (HK2), which is involved in glycolysis, and phosphorylated pyruvate dehydrogenase-E1α (p-PDH), which is involved in oxidative phosphorylation (OxPhos) in colorectal cancer (CRC). The combined evaluation of positive HK2 and negative p-PDH was associated with reduced recurrence-free survival (RFS). This evaluation could predict RFS more precisely than the independent evaluation. The present study indicated that high HK2 expression combined with low p-PDH expression in the invasive front lesions of CRC tumors is predictive of tumor aggressiveness and survival of CRC cases.

  • Novel cancer stem cell marker CD10 in HNSCC (Br. J. Cancer, 111, 506-514, 2014)

    In the collaboration with Department of Otorhinolaryngology-Head and Neck Surgery, Osaka University, Fukusumi et al. found CD10 as a novel marker of therapeutic resistance and cancer stem cells in head and neck squamous cell carcinoma. By studying three HNSCC cell lines (FaDu, Detroit562, and BICR6), treated with cisplatin or radiation, cell surface antigens were analysed by LyoPlateTM, a novel cell surface antigen array. The expression levels of antigens highly expressed after treatments were further compared between cisplatin-resistant Detroit562 cells and its parental line. Association of the candidate antigen with CSCs properties, namely sphere formation and in vivo tumourigenicity, was also examined. The result indicated that CD10, CD15s, CD146, and CD282 were up-regulated across the treated cell lines, while the increased expression of CD10 was prominent in the cisplatin-resistant cell line. FACS-mediated isolation revealed that the CD10-positive subpopulation was more refractory to cisplatin, fluorouracil, and radiation than the CD10-negative subpopulation. It also showed an increased ability to form spheres in vitro and tumours in vivo. Moreover, the CD10-positive subpopulation expressed the CSC marker OCT3/4 at a higher level than that in the CD10-negative subpopulation. Thus CD10 is associated with therapeutic resistance and CSC-like properties of HNSCC. CD10 may serve as a target molecule in the treatment of refractory head and neck squamous cell carcinoma (HNSCC).