Identification of tumor-specific paclitaxel (Taxol)-responsive regulatory elements in the interleukin-8 promoter.
Mol Cell Biol
; 17(9): 5097-105, 1997 Sep.
Article
em En
| MEDLINE
| ID: mdl-9271387
ABSTRACT
Paclitaxel (Taxol) is a novel chemotherapeutic drug that is effective against breast and ovarian cancers. Although the primary target of paclitaxel is microtubules, its efficacy exceeds that of conventional microtubule-disrupting agents, suggesting that it may have additional cellular effects. Previously, we demonstrated that paclitaxel can induce interleukin-8 (IL-8) gene expression at the transcriptional level in subsets of human ovarian cancer lines. In this as well as the previous report, we present evidence that this ability is not linked to the lipopolysaccharide pathway of IL-8 gene induction. The present study identifies the cis-acting elements and trans-acting factors involved in this induction by transfecting DNA constructs containing the 5'-flanking region of the IL-8 gene linked to the chloramphenicol acetyltransferase reporter gene into paclitaxel-responsive and nonresponsive ovarian cancer cells (responsiveness refers to the IL-8 response). Paclitaxel only activated the IL-8 promoter in responsive cells. The AP-1 and NF-kappaB binding sites in the IL-8 promoter are required for activation by paclitaxel; in contrast, a C/EBP site required for IL-8 promoter activation in other cell types is not involved. Gel shift assays demonstrate that paclitaxel causes a marked increase in protein binding to the NF-kappaB and AP-1 consensus binding sequences in the paclitaxel-responsive ovarian cells, but not the nonresponsive cells. The induction of NF-kappaB and AP-1 binding is reduced by the addition of protein kinase C inhibitors and cyclic AMP effector, respectively. These results demonstrate a molecular mechanism for cell-specific paclitaxel-induced IL-8 gene expression which may have clinical relevance.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Interleucina-8
/
Regiões Promotoras Genéticas
/
Paclitaxel
/
Antineoplásicos Fitogênicos
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Humans
Idioma:
En
Revista:
Mol Cell Biol
Ano de publicação:
1997
Tipo de documento:
Article
País de afiliação:
Estados Unidos