Induction of apoptosis and suppression of clonogenicity of ovarian carcinoma cells with estrogen mustard.
BACKGROUND
This study was conducted to evaluate whether estramustine (estrogen mustard [EM]) is a promising alternative in the treatment of patients with epithelial ovarian carcinoma (OVCA). EM is a microtubule-associated protein (MAP) specific antimicrotubule agent with low toxicity.


METHODS
The authors investigated the ability of EM to induce apoptosis and suppress colony formation of OVCA cells. Paclitaxel was used as a positive control. DNA electrophoresis and terminal deoxynucleotidyl dUTP-X nick end labeling (TUNEL) assays were used to detect internucleosomal DNA fragmentation. Flow cytometry was used to identify apoptotic cells and disturbance of the cell cycle of EM-treated OVCA cells further. Quantitation of detached cultured cells also provided a relative estimate of the apoptotic response of OVCA cells to treatment with EM. The colony formation assay was used to evaluate the effects of EM on clonogenicity.


RESULTS
The effects of EM on four OVCA cell lines in culture were highly similar to those of paclitaxel in causing apoptosis and inhibiting clonogenicity. DNA electrophoresis and TUNEL assays showed that EM induced internucleosomal DNA fragmentation in OVCA cells. Flow cytometry showed changes typical of apoptotic changes and cell cycle block and synchronization at the G2/M-phase. Counting of detached cells showed a log-dose response to EM treatment. The colony formation assay also showed a log-dose response suppression of OVCA cell clonogenicity after treatment with EM.


CONCLUSIONS
EM may be a promising candidate in the clinical treatment of patients with OVCA. The lower toxicity and MAP specific action of EM is a novel chemotherapy for OVCA.
Chen
Z
Z
Obstetrics/Gynecology Department, Yale University School of Medicine, New Haven, Connecticut 06520-8063, USA.
Fadiel
A
A
Jia
J F
JF
Sakamoto
H
H
Carbone
R
R
Naftolin
F
F
D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002277:Carcinoma / Q000473:pathology*; D004961:Estramustine / Q000494:pharmacology*; D005260:Female; D006801:Humans; D020287:In Situ Nick-End Labeling; D010051:Ovarian Neoplasms / Q000473:pathology*; D017239:Paclitaxel / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects; D014410:Tumor Stem Cell Assay
D018906:Antineoplastic Agents, Alkylating; D004961:Estramustine; D017239:Paclitaxel