KAWAMATA Hitoshi The University of Tokushima, School of Dentistry, Assistant Professor, 歯学部, 助手(前分担者) (70224847)
YURA Yoshiaki Osaka University, Graduate School of Dentistry, Professor, 大学院・歯学研究科, 教授(前分担者) (00136277)
YOSHIDA Hideo The University of Tokushima, School of Dentistry, Associate Professor, 歯学部, 助教授 (30116131)
1. When human oral squamous cell carcinoma cell lines (BHY, HN: p53 wild type (exon4-9)) and human salivary cancer cell lines (HSG, HSG-AZA1, HSG-AZA3: p53 wild type; TYS : p53 codon 281^<Asp→Hls>) were treated with vesnarinone, inhibition of cell growth and induction of G1 arrest occurred in all of the treated cells, where up-regulation of p21^<Waf1>, p27^<Kip1> and TSC-22 genes as well as down-regulation of p53 gene were detected.
2. When vesnarinone was administered per os into the nude mice bearing TYS tumors, significant inhibition of the tumor growth as well as cellular differentiation into keratinocyte and acinar cells occurred.
3. Vesnarinone was very therapeutically effective for human oral squamous cell carcinoma or for human salivary adenoid cystic carcinoma.
4. We isolated and characterized human TSC-22 gene from the TYS cells treated with vesnarinone.
(1) Down-regulation of TSC-22 gene in human salivary cancer cells, grown in vitro and in nude mice, caused the marked acceleration of tumor growth and up-regulation of the gene inhibited significantly anchorage-independent growth.
(2) Overexpression of TSC-22 protein in TYS cells resulted in the augmented induction of apotosis by anti-cancer drugs (5-FU and CDDP) or radiation.
(3) TSC-22 gene was comprised of 3 exons. Transcription initiatin sites were located at 7bp and 29bp downstream from TATA box like sequence. TSC-22 promoter region contained putative binding sites for transcription factor such as NF-kB, MyoD, AP-1, PU, C/EBP, p53, c-Myb, Sp1, NF1 or Smad.
5. Sp1 and Sp3 transcription factors bound to the vesnarinone-responsive element (Sp1-1 and Sp1-2 sites) present in p21Waf1 promoter in TYS cells.
6. Vesnarinone induced the histone hyperacetylation in TYS cells.