Downregulation of Cap43 gene by von Hippel-Lindau tumor suppressor protein in human renal cancer cells.
We previously identified 9 genes (i.e., thymosin beta4, secreted protein acidic and rich in cysteine, Cap43, ceruloplasmin, serum amyloid A, heat shock protein 90, LOT1, osteopontin and casein kinase Igamma) that are more highly expressed in cancerous regions than in noncancerous regions in human renal cancers. In our study, we considered the possibility that the von Hippel-Lindau (VHL) tumor suppressor gene might be able to affect the expression of these 9 genes in renal cancer cells. We first established 2 VHL-positive cell lines, 786/VHL-1 and 786/VHL-2, after the introduction of wild-type VHL into VHL-negative renal cancer 786-O cells. Of these 9 genes, expression of the Cap43 gene was specifically downregulated by VHL. Expression of Cap43 was also much lower in 4 other VHL-positive renal cancer cell lines than in VHL-negative 786-O cells. Cap43 promoter assays with several deletion or mutation constructs demonstrated that the Sp1 site in the element from -286 base pairs (bp) to -62 bp was partly responsible for VHL-induced suppression of the Cap43 gene. Immunostaining analysis with human specimens of renal cancers demonstrated that the Cap43 protein was expressed in most cancer cells and macrophages. We also observed a marked and specific increase of Cap43 mRNA levels in response to hypoxia or nickel in all VHL-positive cell lines. Cellular expression of Cap43 mRNA in response to hypoxia or nickel thus is closely associated with VHL gene expression in renal cancer cells. Although the function of the Cap43 protein remains unclear, the expression of Cap43 protein could be a molecular marker closely associated with VHL in renal cancer.
Masuda
Katsuaki
K
Department of Medical Biochemistry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Ono
Mayumi
M
Okamoto
Masahiro
M
Morikawa
Wataru
W
Otsubo
Michihiro
M
Migita
Toshiro
T
Tsuneyoshi
Masazumi
M
Okuda
Heiwa
H
Shuin
Taro
T
Naito
Seiji
S
Kuwano
Michihiko
M
D002292:Carcinoma, Renal Cell / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D018797:Cell Cycle Proteins; D015687:Cell Hypoxia; D002460:Cell Line; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007680:Kidney Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008025:Ligases / Q000032:analysis / Q000378:metabolism*; D009532:Nickel / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins / Q000032:analysis / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D000099259:N-myc Downstream-Regulated Gene 1 Protein
D018797:Cell Cycle Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008025:Ligases; D009532:Nickel; D011506:Proteins; D012333:RNA, Messenger; D025521:Tumor Suppressor Proteins; D044767:Ubiquitin-Protein Ligases; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D000099259:N-myc Downstream-Regulated Gene 1 Protein; C497446:VHL protein, human