Abundant nucleostemin expression supports the undifferentiated properties of germ cell tumors

Noriyuki Uema, Takako Ooshio, Kenichi Harada, Masako Naito, Kazuhito Naka, Takayuki Hoshii, Yuko Tadokoro, Kumiko Ohta, Mohamed A.E. Ali, Miyuki Katano, Tomoyoshi Soga, Yasuni Nakanuma, Akihiko Okuda, Atsushi Hirao

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6 Citations (Scopus)

Abstract

Nucleostemin (NS) is a nucleolar GTP-binding protein that is involved in ribosomal biogenesis and protection of telomeres. We investigated the expression of NS in human germ cell tumors and its function in a mouse germ cell tumor model. NS was abundantly expressed in undifferentiated, but not differentiated, types of human testicular germ cell tumors. NS was expressed concomitantly with OCT3/4, a critical regulator of the undifferentiated status of pluripotent stem cells in primordial germ cells and embryonal carcinomas. To investigate the roles of NS in tumor growth in vivo, we used a mouse teratoma model. Analysis of teratomas derived from embryonic stem cells in which the NS promoter drives GFP expression showed that cells highly expressing NS were actively proliferating and exhibited the characteristics of tumor-initiating cells, including the ability to initiate and propagate tumor cells in vivo. NS-expressing cells exhibited higher levels of GTP than non-NS-expressing cells. Because NS protein is stabilized by intracellular GTP, metabolic changes may contribute to abundant NS expression in the undifferentiated cells. OCT3/4 deficiency in teratomas led to loss of NS expression, resulting in growth retardation. Finally, we found that teratomas deficient in NS lost their undifferentiated characteristics, resulting in defective tumor proliferation. These data indicate that abundant expression of NS supports the undifferentiated properties of germ cell tumors.

Original languageEnglish
Pages (from-to)592-603
Number of pages12
JournalAmerican Journal of Pathology
Volume183
Issue number2
DOIs
Publication statusPublished - 2013 Aug 1

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ASJC Scopus subject areas

  • Pathology and Forensic Medicine

Cite this

Uema, N., Ooshio, T., Harada, K., Naito, M., Naka, K., Hoshii, T., Tadokoro, Y., Ohta, K., Ali, M. A. E., Katano, M., Soga, T., Nakanuma, Y., Okuda, A., & Hirao, A. (2013). Abundant nucleostemin expression supports the undifferentiated properties of germ cell tumors. American Journal of Pathology, 183(2), 592-603. https://doi.org/10.1016/j.ajpath.2013.04.018