Journal article
p53 and WAF1 Are Induced and Rb Protein Is Hypophosphorylated during Cell Growth Inhibition by the Thymidylate Synthase Inhibitor ZD1694 (Tomudex)
Molecular pharmacology, Vol.51(4), pp.630-636
04/01/1997
DOI: 10.1124/mol.51.4.630
PMID: 9106628
Abstract
In a previous study, we found that treatment of HCT-8 cells with ZD1694, a specific antifolate-based thymidylate synthase inhibitor, resulted in DNA fragmentation. In this study, we have demonstrated the dose- and time- dependent induction of DNA fragmentation accompanied by elevation of p53 and WAF1 protein expression by ZD1694. WAF1 mRNA showed a time-dependent increase, whereas p53 mRNA was not found to be significantly overexpressed. The initial increase in WAF1 mRNA was detected at 4 hr, but increased WAF1 protein expression was detected 8-24 hr after a 2-hr exposure. The amount of total and hypophosphorylated pRb seems to be rising greatly after ZD1694 exposure. The effects of ZD1694 on the expression of E2F1 and formation of the E2F1-Rb complex were investigated after a 2-hr drug exposure (IC90). The results showed a time-dependent decrease in E2F1 mRNA and protein expression; an increase in the abundance of the E2F-Rb complex could be demonstrated beginning 4 hr after drug exposure by a gel shift assay. Kinetic analysis showed increased availability of hypophosphorylated pRb for inhibition of E2F, which could indirectly result from WAF1-induced inhibition cyclin-dependent kinase activity. Whereas thymidylate synthase inhibition by ZD1694 was rapid in onset and maintained for at least 24 hr after drug treatment, drug-induced cellular growth inhibition was significant 24 hr after drug exposure. The increased abundance of hypophosphorylated pRb and binding to transcription factor E2F-1 is consistent with ZD1694-induced cell growth inhibition in HCT-8 cells. Therefore, the observed effect on downstream events after effective inhibition of thymidylate synthase may offer the critical determinants of response to ZD1694.
Details
- Title: Subtitle
- p53 and WAF1 Are Induced and Rb Protein Is Hypophosphorylated during Cell Growth Inhibition by the Thymidylate Synthase Inhibitor ZD1694 (Tomudex)
- Creators
- Ming-Biao Yin - Roswell Park Cancer InstituteWieland Voigt - Roswell Park Cancer InstituteAngeles Panadero - Roswell Park Cancer InstituteUdo Vanhoefer - Roswell Park Cancer InstituteCheryl Frank - Roswell Park Cancer InstituteSanja Pajovic - Roswell Park Cancer InstituteJane Azizkhan - Roswell Park Cancer InstituteYoucef M. Rustum - Roswell Park Cancer Institute
- Resource Type
- Journal article
- Publication Details
- Molecular pharmacology, Vol.51(4), pp.630-636
- DOI
- 10.1124/mol.51.4.630
- PMID
- 9106628
- ISSN
- 0026-895X
- eISSN
- 1521-0111
- Language
- English
- Date published
- 04/01/1997
- Academic Unit
- Hematology, Oncology, and Blood & Marrow Transplantation; Internal Medicine
- Record Identifier
- 9984359691302771
Metrics
4 Record Views