Yukihisa Minagawa

Glutathione S-transferase-π expression and glutathione concentration in ovarian carcinoma before and after chemotherapy

To clarify the role of glutathione (GSH) in the chemotherapy resistance of ovarian carcinoma, the authors examined the expression of glutathione S‐transferase‐π (GST‐π) and the concentration of glutathione in tumors before and after chemotherapy in the same patients.

The role of neoadjuvant intraarterial infusion chemotherapy with cisplatin and bleomycin for locally advanced cervical cancer

To clarify the effect of neoadjuvant intraarterial infusion chemotherapy on the cure rate in advanced cervical cancer with bulky tumor, a total of 50 patients were examined prospectively. The clinical stage according to the International Federation of Gynecology and Obstetrics (FIGO) classification included 23 IIb, 6 IIIa, and 21 IIIb. These patients were randomly divided into the neoadjuvant intraarterial infusion chemotherapy group and the control group. There were no significant differences in mean age, FIGO clinical stage, and tumor histology between groups. Twenty-five patients in the former group were given 25 mg/m2 of cisplatin and 15 mg/m2 of bleomycin via each internal iliac artery. If the results of the evaluation indicated that surgery was feasible, radical surgery was performed. The patients whose tumors were inoperable received radiation therapy consisting of external irradiation and intracavitary irradiation. Twenty-five patients in the control group also underwent the same radiation therapy. The overall response rate was 80.0%. Eighteen of 20 responders underwent surgery. The 3-year survival rate was 85.7% for operated patients, 42.9% for patients receiving neoadjuvant intraarterial infusion chemotherapy followed by irradiation, and 49.5% for the control group. In the present study, neoadjuvant intraarterial infusion chemotherapy did not improve the prognosis of patients with advanced cervical cancer compared to radiation therapy alone, and only responders who underwent surgery obtained an advantage in survival.

Chemosensitivity and p53-Dependent Apoptosis in Epithelial Ovarian Carcinoma

Although p53 gene mutation frequently is observed in ovarian carcinoma, the function of the p53 gene in chemosensitivity has not been defined conclusively. The objective of the current study was to elucidate the relation between chemotherapy‐induced apoptosis through the p53 pathway and chemosensitivity to ovarian carcinoma.

Synergistic Enhancement of Cisplatin Cytotoxicity by SN‐38, an Active Metabolite of CPT‐11, for Cisplatin‐resistant HeLa Cells

A cisplatin (cis‐diamininedichloroplatinuin(II); CDDP)‐resistant HeLa cell line (HeLa/CDDP cells), which showed more than 8‐fold resistance to CDDF compared to the parent cells, was newly established for this study. HeLa/CDDP cells accumulated 50% less platinum than the parent cells. There was no difference in intracellular glutathione (GSH) content between the parent and HeLa/ CDDP cells. The dose modification factor by DL‐buthionine‐S, R‐sulfoximine (BSO) pretreatment was similar in both cell lines. HeLa/CDDP cells had cross‐resistance to diammine (l, l‐cyclobutanedicarboxylato)platinum(II) (CBDCA), (cis‐diammine (glycolato)platinum (254‐S), but not to (‐)‐(R)‐2‐aminomethylpyrrolidine(1,1‐cyclobutanedicarboxylato)platinum(II) (DWA2114R), adriamycin, or VP‐16. HeLa/CDDP cells showed a collateral sensitivity to 7‐ethyl‐10‐hydroxycampto‐thecin (SN‐38), an active metabolite of 7‐ethyl‐10‐[4‐(l‐piperidino)‐l‐piperidino]carbonyloxycamptothecin (CPT‐11). Furthermore, isobologram analysis indicated synergistic interaction of CDDP and SN‐38 only for HeLa/CDDP cells. The present study suggests that combination therapy with CDDP and CPT‐11 may he potentially useful in the treatment of some patients with CDDP‐resistant cancer.

Cisplatin-resistant HeLa cells are resistant to apoptosis via p53-dependent and -independent pathways.

Since HeLa cells possess very little functional p53 activity, they could be originally resistant to genotoxic stress‐induced apoptosis. Therefore, it is likely that the drug‐resistant cells derived from HeLa cells are more resistant to apoptosis. The aim of this study was to determine whether cisplatin‐resistant cells derived from HeLa cells have an apoptosis‐resistant phenotype. A cisplatin‐resistant cell subline, HeLa/CDDP cells, showed a 19‐fold resistance to cisplatin compared with the parent cells. The subline showed a collateral sensitivity to paclitaxel. An equitoxic dose (IC50) of cisplatin produced DNA fragmentation in HeLa cells but not in HeLa/CDDP cells. Transfection of wild‐type p53gene enhanced the cytotoxicity of cisplatin and cisplatin‐induced apoptosis in HeLa cells but not in HeLa/CDDP cells, although it caused p53 overexpression in both cell lines. The expression of caspase 1 (interleukin‐1β‐converting enzyme, ICE) mRNA and the overexpression of bax protein were observed only in HeLa cells. Paclitaxel‐induced DNA fragmentation appeared less in HeLa/CDDP cells than in HeLa cells. p53gene transfection did not affect the extent of DNA fragmentation in either cell line, suggesting that paclitaxel may induce p53‐independent apoptosis. These findings suggest that HeLa/CDDP cells may have an acquired phenotype that is resistant to p53‐dependent and ‐independent apoptosis.

Tumor DNA ploidy and prognosis of patients with serous cystadenocarcinoma of the ovary.

Background. Although it is important to determine any relationship between tumor DNA ploidy and its biologic behavior, the correlation between DNA ploidy and the prognosis of patients with ovarian cancer is not conclusive. Accordingly, the authors evaluated the clinical application of DNA ploidy in ovarian cancer.

Alteration of Telomerase Activity Associated With Development and Extension of Epithelial Ovarian Cancer

Objective To assess telomerase activity associated with the development and extension of epithelial ovarian cancer and to investigate the relationship between p53 gene status and telomerase activity. Methods A total of 53 samples (41 epithelial ovarian cancers, five borderline epithelial tumors, four benign adenomas, and three surface epithelia) were examined for telomerase activity by the polymerase chain reaction (PCR) -based telomeric repeat amplification protocol assay. Mutations in the p53 gene were determined by PCR-single strand conformation polymorphism analysis. Results Telomerase activity was detected in 33 of 41 epithelial ovarian cancers and in three of five borderline malignancies but was not detectable in either benign tumors or normal surface epithelium. The mean (± standard deviation [SD]) intensity of telomerase activity in cancers was significantly higher than that in borderline malignancies (10.6 ± 8.2 versus 3.6 ± 1.3). The positivity of telomerase activity did not correlate with any clinical findings, but the intensity (±SD) of telomerase activity was significantly higher in tumors with lymph node involvement (12.2 ± 8.3 versus 3.8 ± 1.1). Mutations of the p53 gene were observed in 44% of ovarian cancers; p53 gene status did not relate to telomerase activity. Multivariate analysis showed that the intensity of telomerase activity was not an independent factor for prognosis of patients with ovarian cancer. Conclusion Telomerase activity may be associated with development and extension of epithelial ovarian cancer.

Transvaginal Ultrasonography and Endometrial Cytology as a Diagnostic Schema for Endometrial Cancer

Objective: To determine whether the combined use of transvaginal ultrasonography and endometrial cytology is an effective diagnostic schema for endometrial cancer and hyperplasia of the uterus. Methods: Five hundred fifty-two women were enrolled in this study. For all subjects, endometrial thickness was evaluated by transvaginal ultrasonography. Endometrial cytology was carried out according to the following criteria: all women with atypical uterine bleeding, for asymptomatic postmenopausal women with endometrial thickness ≧5 mm, and for asymptomatic premenopausal women with endometrial thickness ≧20 mm. When the cytological findings were abnormal, we performed a hysteroscopy-guided biopsy within 2 weeks. Women who received transvaginal ultrasonography alone, or those who showed negative cytology, underwent repeated gynecological examination and transvaginal ultrasonography 3, 6, and 12 months after the first examination. Results: Endometrial cytology was done on 129 women (23.4% of all subjects), of whom 14 were diagnosed as ‘positive’ cytology, 20 as ‘suspicious positive’, and 95 as ‘negative’. A total of 34 women with ‘positive’ or ‘suspicious positive’ cytological result underwent hysteroscopy-guided endometrial biopsy. The histological diagnosis of the endometrium included 13 endometrial cancers, 9 endometrial hyperplasias (one atypical hyperplasia and 3 hyperplastic polyps), and 10 normal endometria. As a diagnostic schema for endometrial cancer, this combined method resulted in 100% sensitivity, 99.1% specificity, 92.9% positive predictive value, and 100% negative predictive value. For endometrial hyperplasia, the method resulted in 100% sensitivity, 89.6% specificity, 40.0% positive predictive value, and 100% negative predictive value. Conclusion: A combination of transvaginal ultrasonography and endometrial cytology may be an effective diagnostic schema for endometrial cancer and hyperplasia.

Significance of cytoreductive surgery including bowel resection for patients with advanced ovarian cancer.

The aim of this study was to determine the significance of bowel resection in advanced ovarian cancer. A total of 64 women with stage IIIc or IV epithelial ovarian cancer, who consecutively received primary treatment between 1991 and 1995, were entered in this prospective study. The outcome of the patients undergoing bowel resection was evaluated. Thirty-nine patients underwent cytoreductive surgery at initial surgery. Of them, 16 patients could undergo optimal operation without bowel resection. Twenty-three patients received bowel resection at initial surgery. Of these 23 patients, 16 underwent optimal operation and 7 did not. Among 25 patients judged as inoperable cases at initial surgery, 21 responded to chemotherapy and underwent second surgery. Of 21 patients receiving second surgery, 15 underwent optimal operation (7 without bowel resection and 8 with bowel resection). The 3-year survival rate for 24 patients undergoing optimal operation with bowel resection (46.8%) was not significantly different from that for 23 patients without bowel resection (59.1%). Postoperative complications were seen in 8 patients (21.6%) of the patients receiving bowel resection and 3 (13.0%) of those without bowel resection. Cytoreductive surgery including bowel resection is effective for an improvement of the survival in patients with advanced ovarian cancer, if an optimal operation can be performed.

Cellular Efflux Pump and Interaction between Cisplatin and Paclitaxel in Ovarian Cancer Cells

Objective: The aim of this study was to evaluate the combination effect of paclitaxel (PTX) and cisplatin (CDDP) and to determine the mechanisms of interaction between these agents. Methods and Results: We used human ovarian adenocarcinoma cell lines, namely a parent cell line (KF), a CDDP-resistant cell line (KFr) and a PTX-resistant cell line (KFTx).The combination effect of PTX and CDDP was synergistic on KF and KFTx and additive on KFr. The incidence of anaphase or telophase, evaluated by immunofluorescence microscopy, decreased with PTX and significantly decreased with PTX and CDDP in KF and KFTx. The concentration of PTX, which was measured by high-performance liquid chromatography, was higher in KF and KFTx cells treated with a combination of PTX and CDDP than those treated with PTX alone. Multidrug resistance gene mRNA appeared in KFTx and its expression decreased after exposure to PTX and CDDP. After exposure to CDDP, the expression of multidrug resistance-associated protein (MRP) and the concentration of glutathione increased in KF, but not in KFr or KFTx. MRP expression slightly increased in KF and KFTx after exposure to PTX. In contrast, its expression decreased in KFr. Conclusion: The present study suggests that CDDP enhances PTX accumulation and that the interaction of these agents is synergistic in CDDP-sensitive cells.