Drug-induced apoptosis and p53, BCL-2 and BAX expression in breast cancer tissues in vivo and in fibroblast cells in vitro.
BACKGROUND
Chemotherapeutic management of breast cancers is a difficult task as they show significant differences in chemosensitivity. The present study was undertaken to determine the usefulness of the apoptosis-related factors as indicators of tumor sensitivity to 5'-deoxyfluorouridine (5'-DFUR) in breast cancers.


METHODS
(1) Forty-six breast cancer patients were randomly assigned to a group in which oral 5'-DFUR (1200 mg/day) was administered for more than 5 days before operation (24 patients) and a control group who received no preoperative chemotherapy (22 patients). Surgical specimens were examined for the frequency of apoptotic cells [apoptotic index (AI)] by a terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling method and for the expression of p53, BCL-2 and BAX by immunohistochemical staining. (2) Normal human diploid fetal lung fibroblast, IMR90 and SV40 transformed IMR90 were exposed to 5-FU. Apoptotic cells were detected by flow cytometry and BCL-2 and BAX mRNAs by real-time quantitative RT-PCR analysis.


RESULTS
(1) No significant difference in the AIs or in BCL-2 and BAX scores was observed between the 5'-DFUR-treated and control groups. However, in the p53 negative subgroup (n = 36), AI and BAX scores were higher and BCL-2 scores lower in the 5'-DFUR group than in the control group (P = 0.006, 0.008 and 0.050, respectively). (2) The sensitivity of IMR90 was significantly decreased by SV40 transformation and the 5-FU-induced cytotoxicity was mainly due to induction of apoptosis. The BCL-2/BAX mRNA ratio was decreased in response to 5-FU in IMR90. These results correlated with our clinical data.


CONCLUSIONS
Preoperative treatment with 5'-DFUR induced apoptosis and changes in BCL-2 and BAX expression in p53 negative breast cancers. p53 status, AI and the BCL-2/BAX ratio may be useful information for the choice of postoperative chemotherapy for breast cancer.
Suzuki
K
K
First Department of Surgery, Hamamatsu University School of Medicine, Shizuoka, Japan.
Kazui
T
T
Yoshida
M
M
Uno
T
T
Kobayashi
T
T
Kimura
T
T
Yoshida
T
T
Sugimura
H
H
D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D005434:Flow Cytometry; D005467:Floxuridine / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D007124:Immunoenzyme Techniques; D007150:Immunohistochemistry; D008875:Middle Aged; D011355:Prodrugs / Q000627:therapeutic use; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000378:metabolism; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis*; D051028:bcl-2-Associated X Protein
D000970:Antineoplastic Agents; C494826:BAX protein, human; D011355:Prodrugs; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D005467:Floxuridine; C025034:doxifluridine