Miyuki Ozaki

Publications (8)14.71 Total impact

• Article: Adipose-derived mesenchymal stem cells and regenerative medicine.

  Masamitsu Konno, Atsushi Hamabe, Shinichiro Hasegawa, Hisataka Ogawa, Takahito Fukusumi, Shimpei Nishikawa, Katsuya Ohta, Yoshihiro Kano, Miyuki Ozaki, Yuko Noguchi, Daisuke Sakai, Toshihiro Kudoh, Koichi Kawamoto, Hidetoshi Eguchi, Taroh Satoh, Masahiro Tanemura, Hiroaki Nagano, Yuichiro Doki, Masaki Mori, Hideshi Ishii
  [show abstract] [hide abstract]
  ABSTRACT: Adipose tissue-derived mesenchymal stem cells (ADSCs) are multipotent and can differentiate into various cell types, including osteocytes, adipocytes, neural cells, vascular endothelial cells, cardiomyocytes, pancreatic β-cells, and hepatocytes. Compared with the extraction of other stem cells such as bone marrow-derived mesenchymal stem cells (BMSCs), that of ADSCs requires minimally invasive techniques. In the field of regenerative medicine, the use of autologous cells is preferable to embryonic stem cells or induced pluripotent stem cells. Therefore, ADSCs are a useful resource for drug screening and regenerative medicine. Here we present the methods and mechanisms underlying the induction of multilineage cells from ADSCs.
  Embryologia 03/2013; · 2.21 Impact Factor
• Source

  Available from: Hirofumi Yamamoto

  Article: Depletion of JARID1B induces cellular senescence in human colorectal cancer.

  Katsuya Ohta, Naotsugu Haraguchi, Yoshihiro Kano, Yoshinori Kagawa, Masamitsu Konno, Shimpei Nishikawa, Atsushi Hamabe, Shinichiro Hasegawa, Hisataka Ogawa, Takahito Fukusumi, [......], Miyuki Ozaki, Toshihiro Kudo, Daisuke Sakai, Taroh Satoh, Miwa Fukami, Masaru Ishii, Hirofumi Yamamoto, Yuichiro Doki, Masaki Mori, Hideshi Ishii
  [show abstract] [hide abstract]
  ABSTRACT: The global incidence of colorectal cancer (CRC) is increasing. Although there are emerging epigenetic factors that contribute to the occurrence, development and metastasis of CRC, the biological significance of epigenetic molecular regulation in different subpopulations such as cancer stem cells remains to be elucidated. In this study, we investigated the functional roles of the H3K4 demethylase, jumonji, AT rich interactive domain 1B (JARID1B), an epigenetic factor required for the continuous cell growth of melanomas, in CRC. We found that CD44+/aldehyde dehydrogenase (ALDH)+ slowly proliferating immature CRC stem cell populations expressed relatively low levels of JARID1B and the differentiation marker, CD20, as well as relatively high levels of the tumor suppressor, p16̸INK4A. Of note, lentiviral‑mediated continuous JARID1B depletion resulted in the loss of epithelial differentiation and suppressed CRC cell growth, which was associated with the induction of phosphorylation by the c‑Jun N‑terminal kinase (Jnk̸Sapk) and senescence‑associated β‑galactosidase activity. Moreover, green fluorescent‑labeled cell tracking indicated that JARID1B‑positive CRC cells had greater tumorigenicity than JARID1B‑negative CRC cells after their subcutaneous inoculation into immunodeficient mice, although JARID1B‑negative CRC cells resumed normal growth after a month, suggesting that continuous JARID1B inhibition is necessary for tumor eradication. Thus, JARID1B plays a role in CRC maintenance. JARID1B may be a novel molecular target for therapy‑resistant cancer cells by the induction of cellular senescence.
  International Journal of Oncology 01/2013; · 2.40 Impact Factor
• Article: microRNA-based cancer cell reprogramming technology.

  Shimpei Nishikawa, Hideshi Ishii, Naotsugu Haraguchi, Yoshihiro Kano, Takahito Fukusumi, Katsuya Ohta, Miyuki Ozaki, Dyah Laksmi Dewi, Daisuke Sakai, Taroh Satoh, Hiroaki Nagano, Yuichiro Doki, Masaki Mori
  [show abstract] [hide abstract]
  ABSTRACT: Epigenetic modifications play crucial roles in cancer initiation and development. Complete reprogramming can be achieved through the introduction of defined biological factors such as Oct4, Sox2, Klf4, and cMyc into mouse and human fibroblasts. Introduction of these transcription factors resulted in the modification of malignant phenotype behavior. Recent studies have shown that human and mouse somatic cells can be reprogrammed to become induced pluripotent stem cells using forced expression of microRNAs, which completely eliminates the need for ectopic protein expression. Considering the usefulness of RNA molecules, microRNA-based reprogramming technology may have future applications in regenerative and cancer medicine.
  Experimental and therapeutic medicine 07/2012; 4(1):8-14.
• Article: Transcriptomic study of dormant gastrointestinal cancer stem cells.

  Shimpei Nishikawa, Dyah Laksmi Dewi, Hideshi Ishii, Masamitsu Konno, Naotsugu Haraguchi, Yoshihiro Kano, Takahito Fukusumi, Katsuya Ohta, Yuko Noguchi, Miyuki Ozaki, Daisuke Sakai, Taroh Satoh, Yuichiro Doki, Masaki Mori
  [show abstract] [hide abstract]
  ABSTRACT: We previously discovered the coexistence of dormant and proliferating cancer stem cells (CSCs) in gastrointestinal cancer, which leads to chemoradiation resistance. CD13-/CD90+ proliferating liver CSCs are sensitive to chemotherapy, and CD13+/CD90- dormant CSCs have a limited proliferation ability, survive in hypoxic areas with reduced oxidative stress, and relapse and metastasize to other organs. In such CD13+ dormant cells, non-homologous end-joining, an error-prone repair mechanism, is dominant after DNA damage, whereas high-fidelity homologous recombination is apparent in CD13- proliferating cells, suggesting the significance of dormancy as an essential protective mechanism of therapy resistance. However, this mechanism may also play a role in the generation and accumulation of heterogeneity during cancer progression, although the exact mechanism remains to be understood. Through transcriptomic study, we elucidated the underlying epigenetic mechanism for malignant behavior of dormant CSCs, i.e., simultaneous activation of several pathways including EZH2- and TP53-related proteins in response to microRNA101, suggesting that a pharmacogenomic approach would open an era to novel molecular targeting cancer therapy.
  International Journal of Oncology 06/2012; 41(3):979-84. · 2.40 Impact Factor
• Article: Genotoxic therapy stimulates error-prone DNA repair in dormant hepatocellular cancer stem cells.

  Shimpei Nishikawa, Hideshi Ishii, Naotsugu Haraguchi, Yoshihiro Kano, Takahito Fukusumi, Katsuya Ohta, Miyuki Ozaki, Daisuke Sakai, Taroh Satoh, Hiroaki Nagano, Yuichiro Doki, Masaki Mori
  [show abstract] [hide abstract]
  ABSTRACT: Previous studies have described distinct dormant and proliferating populations of cancer stem cells in hepatocellular carcinoma. The CD13 protein is involved in the scavenging of reactive oxygen species through the glutathione reductase pathway and is associated with resistance to chemotherapy. Whereas CD13(-) proliferating cancer stem cells are sensitive to chemotherapy, CD13(+) dormant cancer stem cells are associated with the development of resistance to chemotherapy. CD13(+) cells in hypoxic areas of the tumour survive chemotherapy, leading to subsequent disease relapse and metastasis. Whether CD13(+) dormant cells simply resume proliferation following therapy or whether they also acquire greater malignant potential, remains unknown. The mechanisms involved also remain unclear. In the present study, we investigated the repair of DNA damage in CD13(+) dormant and CD13(-) proliferating cells. Total RNA was extracted from tissues, and quantitative real-time polymerase chain reaction (PCR) was performed for specific genes and GAPDH following PCR. Products were then subjected to a temperature gradient of 55-95°C with continuous fluorescence monitoring to generate a melting curve. Cells were incubated with primary antibodies, washed twice, incubated with fluorescent-labelled secondary antibodies for 30 min on ice and analyzed by flow cytometry. The results revealed that the repair of DNA damage in CD13(+) dormant cells occurs predominantly through non-homologous end-joining, a repair process that is error-prone, whereas CD13(-) proliferating cells primarily utilise high-fidelity homologous recombination for DNA repair. These data indicate that not only is dormancy a protective mechanism for cancer stem cells to survive therapy, but it also enhances the generation and accumulation of mutations following DNA damage. Therefore, the CD13(+) dormant cancer stem cells must be eradicated fully to achieve complete remission of cancer.
  Experimental and therapeutic medicine 06/2012; 3(6):959-962.
• Article: Dicer 1, ribonuclease type III modulates a reprogramming effect in colorectal cancer cells.

  Dyah Laksmi Dewi, Hideshi Ishii, Naotsugu Haraguchi, Shimpei Nishikawa, Yoshihiro Kano, Takahito Fukusumi, Miyuki Ozaki, Toshiyuki Saito, Daisuke Sakai, Taroh Satoh, Yuichiro Doki, Masaki Mori
  [show abstract] [hide abstract]
  ABSTRACT: Complete cell reprogramming can be achieved by the introduction of specific transcription factors, Oct4 [also known as POU class 5 homeobox 1 (Pou5f1)]; sex-determining region Y (SRY)-box 2 (Sox2); Kruppel-like factor 4 (Klf4); and myelocytomatosis viral oncogene homolog (c-Myc), into terminally differentiated mouse somatic fibroblasts. This reprogramming process may be accelerated or suppressed by various factors, including microRNAs (miRNAs). Introduction of these transcription factors or miRNAs considerably modifies the malignant phenotype of cancer cells. We studied the effect of introducing these transcription factors into two distinct colorectal cancer (CRC) cell lines, HCT116 and DLD-1, in the presence and absence of Dicer 1, ribonuclease type III (Dicer1), a critical miRNA processing enzyme. We assessed cell reprogramming based on the number of cells exhibiting alkaline phosphatase staining and an increase in embryonic stem cell-like gene expression, indicating the return of cells to an immature state. Dicer1-deficient CRC cells showed a reduced number of alkaline phosphatase-positive reprogrammed cells than wild-type (WT) cells. Before reprogramming, endogenous expression of an immature carbohydrate epitope, TRA-1-60, was high in Dicer1-deficient CRC cells, whereas after reprogramming, the expression of this epitope was increased in Dicer1-sufficient more than in Dicer1-deficient CRC cells. Our data demonstrate the critical role of miRNAs in the reprogramming process and determination of a differentiated phenotype of CRC cells.
  International Journal of Molecular Medicine 03/2012; 29(6):1060-4. · 1.98 Impact Factor
• Article: Hypoxia and TP53 deficiency for induced pluripotent stem cell-like properties in gastrointestinal cancer.

  Hiromitsu Hoshino, Hiroaki Nagano, Naotsugu Haraguchi, Shimpei Nishikawa, Akira Tomokuni, Yoshihiro Kano, Takahito Fukusumi, Toshiyuki Saito, Miyuki Ozaki, Daisuke Sakai, Taroh Satoh, Hidetoshi Eguchi, Mitsugu Sekimoto, Yuichiro Doki, Masaki Mori, Hideshi Ishii
  [show abstract] [hide abstract]
  ABSTRACT: Induced pluripotent stem (iPS)-like cancer cells (iPC) by the introduction of defined transcription factors reduce the prevalence of the malignant phenotype of digestive system cancer cells, but the induction efficiency is low. The role of hypoxia and TP53 deficiency in iPC cell generation remain unclear. Cellular reprogramming was performed by retroviral infection with OCT3/4, SOX2, KLF4 and c-MYC of wild-type HCT116 colorectal cancer cells and mutant TP53-deficient HCT116 cells. Cells were cultured in normoxia (21% O2) or hypoxia (5% O2) for 30 days after transduction, and the response to hypoxia and comparison of cellular proliferation, invasion and tumourigenesis before and after iPC cell generation were studied. iPC cell generation from wild-type HCT116 cells in hypoxia was approximately 4-times greater than in normoxia (p<0.05), and TP53 deficiency increased conversion efficiency significantly in normoxia (p<0.05). Significant involvement of hypoxia-inducible factors was observed in an immature carbohydrate epitope, Tra-1-60+, colony formation. Generated iPC cells exhibited multi-differentiation potential. Although the iPC cells in hypoxia exhibited reduced proliferation, invasiveness and tumourigenicity, TP53 deficiency in iPC cells resulted in higher tumourigenicity than in wild-type cells. Both hypoxia and TP53 deficiency increase iPC cell generation. TP53 deficiency can also result in deleterious mutations, whereas hypoxia may impact molecular targets of epigenome normalisation.
  International Journal of Oncology 01/2012; 40(5):1423-30. · 2.40 Impact Factor
• Article: Reprogramming of gastrointestinal cancer cells.

  DyahLaksmi Dewi, Hideshi Ishii, Naotsugu Haraguchi, Shimpei Nishikawa, Yoshihiro Kano, Takahito Fukusumi, Katsuya Ohta, Susumu Miyazaki, Miyuki Ozaki, Daisuke Sakai, Taroh Satoh, Hiroaki Nagano, Yuichiro Doki, Masaki Mori
  [show abstract] [hide abstract]
  ABSTRACT: Cell reprogramming reverts cells to multipotent, preprogrammed states by re-establishing epigenetic markers. It can also induce considerable malignant phenotype modification. Because key events in cancer relapse and metastasis, including epithelial-mesenchymal transition phenotypes, are regulated primarily by reversible and transient epigenetic modifications rather than the accumulation of irreversible and stable genetic abnormalities, studying dynamic mechanisms regulating these biological processes is important. Transcription factors for induced pluripotent stem cells and non-coding microRNAs allow pluripotent phenotype induction. We present the current knowledge of the possible applications of cell reprogramming in reducing aggressive phenotype expression, which can induce tumor cell hibernation and maintain appropriate phenotypes, thereby minimizing relapse and metastasis after surgical resection of gastrointestinal cancer.
  Cancer Science 12/2011; 103(3):393-9. · 3.33 Impact Factor