Proximal 5'-flanking sequence of the human gamma-glutamylcysteine synthetase heavy subunit gene is involved in cisplatin-induced transcriptional up-regulation in a lung cancer cell line SBC-3.
The contribution of the 5'-flanking sequence of the human gamma-glutamylcysteine synthetase heavy subunit (gamma-GCSh) gene to cisplatin-induced transcriptional up-regulation was studied using various human growth hormone reporter constructs which were transfected to a human lung cancer cell line SBC-3. Cisplatin at the concentration of 3 microM increased the transcriptional activity of the longest sequence from -1,413 to +91 bp of the gamma-GCSh gene to 246% of that in non-exposed cells. The distal sequence from -1,413 to -193 bp was shown to negatively regulate transcriptional activity in both cisplatin-exposed and non-exposed cells using deletion and thymidine kinase (TK) promoter-linked constructs. Cisplatin increased the transcriptional activity of the proximal GC-rich sequence from -192 to +91 bp to 340%, of which magnitude was the maximum among deletion constructs. A deletion from -108 to -28 bp, or +34 to +91 bp significantly decreased cisplatin-induced increases in transcriptional activity from 258 to 105%, or 340 to 160%, respectively. When the sequence from -108 to -22 bp, or +26 to +91 bp was linked to the heterologous TK promoter, cisplatin increased the transcriptional activity to 171 or 181%, respectively, from that of 128 or 137%, respectively, in non-exposed cells. These findings indicate that the proximal sequence from -192 to +91 bp of the gamma-GCSh gene, especially from -108 to -28 bp, and +34 to +91 bp, is involved in cisplatin-induced transcriptional up-regulation in SBC-3 cells.
Tomonari
A
A
Pharmacology Division, National Cancer Center Research Institute, Chuo-ku, Tokyo, Japan.
Nishio
K
K
Kurokawa
H
H
Fukumoto
H
H
Fukuoka
K
K
Iwamoto
Y
Y
Usuda
J
J
Suzuki
T
T
Itakura
M
M
Saijo
N
N
D000970:Antineoplastic Agents / Q000494:pharmacology*; D001483:Base Sequence; D018288:Carcinoma, Small Cell / Q000378:metabolism*; D002945:Cisplatin / Q000494:pharmacology*; D004247:DNA / Q000737:chemistry; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D005721:Glutamate-Cysteine Ligase / Q000235:genetics*; D019382:Human Growth Hormone / Q000235:genetics; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D013937:Thymidine Kinase / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D019382:Human Growth Hormone; D004247:DNA; D013937:Thymidine Kinase; D005721:Glutamate-Cysteine Ligase; D002945:Cisplatin