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1996 Fiscal Year Final Research Report Summary

Growth and differentiation of keratinocytes : Molecular and histological study

Research Project

Project/Area Number 07807168
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Morphological basic dentistry
Research InstitutionKyushu Dental College

Principal Investigator

HARADA Hidemitsu  Kyushu Dental College, Department of Oral Anatomy II,Assistant of Professor, 歯学部, 講師 (70271210)

Co-Investigator(Kenkyū-buntansha) TANDLER Bernard  Kyushu Dental College, Department of Oral Anatomy II,Assistant of Professor, 歯学部, 助手 (90271212)
TOYOSHIMA Kuniaki  Kyushu Dental College, Department of Oral Anatomy II,Chief Professor, 歯学部, 教授 (10112559)
Project Period (FY) 1995 – 1996
KeywordsKeratinocytes / bcl-2 / bcl-XL / BAX / apoptosis / differentiation
Research Abstract

Oral keratinocytes originate from basal cells, differentiate during migration to the surface, and finally are shed. Apoptosis occurs at the end of differentiation, but the precise relationship between terminal differentiation and apoptosis is not clear. In the present study, The bcl-2 proto-oncogene is a known inhibitor of apoptosis ; in normal human stratified squamous epithelium its expression is restricted to the basal cell layr. Bcl-xL was expressed in the basal cell and spinous cell layrs, and Bax was expressed in the spinous cell and granular cell layrs. In cultured keratinocytes, Bcl-xL was expressed under conditions of 0.1 mM calcium (low Ca2+) but disappeared under conditions of 1.0 mM calcium (high Ca2+) ; the latter induces keratinocyte differentiation. Bax was not expressed in keratinocytes with low Ca2+ but was expressed in cells with high Ca2+. And finally keratinocytes with high Ca2+ underwent apoptosis, which was detected by the TUNEL method and by 180-bp DNA fragmentation. To investigate the functional role of bcl-2 protein in the process of differentiation of oral keratinocytes, bcl-2 expression vector was transfected into SCC-25 cells, which normally undergo squamous cell differentiation in vitro while expressing specific differentiation markers, e.g., keratin10/11 and involucrin. In bcl-2 transfected SCC-25 cells, the expression of these differentiation markers was markedly suppressed.The bcl-2 proto-oncogene may play a critical role in opposing the commitment to terminal differentiation and apoptosis of oral keratinocytes. These results suggest that the process of terminal differentiation in gingival epithelium is a pathway to apoptosis.

  • Research Products

    (4 results)

All Other

All Publications (4 results)

  • [Publications] Yuka Maruoka, Hidemitsu Harada et al.: "Keratinocytes become terminally differentiated in a process involving programmed cell death" Biochemical and Biophysical Research Communications. 238. 886-890 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Hidemitsu Harada, et al.: "Overexpression of bcl-2 protein inhibits terminal differentiation of oral keratinocytes in vitro." Journal of oral pathology & Medicine. 27. 11-18 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yuka Maruoka, Hidemitsu Harada, Takeshi Mitsuyasu, Yuji Seta, Hideo Kurokawa, Minoru Kajiyama, Kuniaki Toyoshima: "Keratinocytes become terminally differentiated in a process involving programd cell death." Biochem.Biophys.Res.Commun.238. 886-890 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hidemitsu Harada, Takeshi Mitsuyasu, Yuji Seta, Yuka Maruoka, Kuniaki Toyoshima, Shigeru Yasumoto: "Overexpression of bcl-2 protein inhibits terminal differentiation of oral keratinocytes in vitro." J.Oral Pathol.Med.27. 11-17 (1998)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-03-16   Modified: 2021-04-07  

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