Pharmaceutical Society of Japan Acta Medica Okayama 0918-6158 44 7 2021 PC3-secreted microprotein is expressed in glioblastoma stem-like cells and human glioma tissues 910 919 EN Masato Maruyama Department of Anatomy and Brain Science, Kansai Medical University Yousuke Nakano Department of Anatomy and Brain Science, Kansai Medical University Takuya Nishimura Department of Anatomy and Brain Science, Kansai Medical University Ryoichi Iwata Department of Neurosurgery, Kansai Medical University Satoshi Matsuda Department of Cell Signaling, Institute of Biomedical Science, Kansai Medical University Mikio Hayashi Department of Physiology, Kansai Medical University Yuki Nakai Department of Anatomy and Brain Science, Kansai Medical University Masahiro Nonaka Department of Neurosurgery, Kansai Medical University Tetsuo Sugimoto Department of Anatomy and Brain Science, Kansai Medical University Glioblastoma multiforme (GBM) is the most prevalent malignant primary brain tumor with a high recurrence rate. Despite multimodal therapy including surgical resection, chemotherapy, and radiotherapy, the median survival time after the initial diagnosis of GBM is approximately 14 months. Since cancer stem cells (CSCs) are considered the leading cause of cancer recurrence, glioblastoma stem cell-targeted therapy is a promising strategy for the treatment of GBM. However, because CSC heterogeneity has been implicated in the difficulties of CSC-target therapy, more in-depth knowledge of CSC biology is still required to develop novel therapies. In this study, we established single cell-derived tumorspheres from human glioblastoma U87MG cells. One of these tumorspheres, P4E8 clone, showed CSC-like phenotypes, such as self-renewal capacity, expression of CSC markers, resistance to anti-cancer agents, and in vivo tumorigenicity. Therefore, we used P4E8 cells as a cell-based model of glioblastoma stem cells (GSCs). Gene expression analysis using microarray indicated that the most highly expressed genes in P4E8 cells compared to the parental U87MG were PC3-secreted microprotein (MSMP). Furthermore, MSMP was expressed in patient-derived GSCs and human glioma tissues at the protein level, implying that MSMP might contribute to glioma development and progression. No potential conflict of interest relevant to this article was reported.