Over-expression of TSC-22 (TGF-beta stimulated clone-22) markedly enhances 5-fluorouracil-induced apoptosis in a human salivary gland cancer cell line.
We have recently isolated TSC-22 (transforming growth factor-beta-stimulated clone-22) cDNA as an anticancer, drug-inducible (with vesnarinone) gene in a human salivary gland cancer cell line, TYS. We have also reported that TSC-22 negatively regulates the growth of TYS cells and that down-regulation of TSC-22 in TYS cells plays a major role in salivary gland tumorigenesis (Nakashiro et al, 1998). In this study, we transfected TYS cells with an expression vector encoding the TSC-22-GFP (green fluorescent protein) fusion protein, and we established TSC-22-GFP-expressing TYS cell clones. Next, we examined (a) the subcellular localization of the fusion protein, (b) the sensitivity of the transfectants to several anticancer drugs (5-fluorouracil, cis-diaminedichloroplatinum, peplomycin), and (c) induction of apoptotic cell death in the transfectants by 5-fluorouracil treatment. The TSC-22-GFP fusion protein was clearly localized to the cytoplasm, but not to the nucleus. Over-expression of the TSC-22-GFP fusion protein did not affect cell growth, but significantly increased the sensitivity of the cells to the anticancer drugs (p < 0.01; one-way ANOVA). Furthermore, over-expression of the TSC-22-GFP fusion protein markedly enhanced 5-fluorouracil-induced apoptosis. These findings suggest that over-expression of TSC-22-GFP protein in TYS cells enhances the chemosensitivity of the cells via induction of apoptosis.
Uchida
D
D
Second Department of Oral and Maxillofacial Surgery, Tokushima University School of Dentistry, Japan.
Kawamata
H
H
Omotehara
F
F
Miwa
Y
Y
Hino
S
S
Begum
N M
NM
Yoshida
H
H
Sato
M
M
D000970:Antineoplastic Agents / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002448:Cell Adhesion; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002843:Chromatin / Q000187:drug effects / Q000648:ultrastructure; D002945:Cisplatin / Q000633:toxicity; D005472:Fluorouracil / Q000633:toxicity*; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D017663:Peplomycin / Q000633:toxicity; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012468:Salivary Gland Neoplasms; D014158:Transcription, Genetic; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D002843:Chromatin; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D016212:Transforming Growth Factor beta; D049452:Green Fluorescent Proteins; D017663:Peplomycin; D002945:Cisplatin; D005472:Fluorouracil