Phase II study of high-dose cisplatin, etoposide, and cyclophosphamide for refractory ovarian cancer

Fuzheng Qingjie granules potentiate the anticancer effect of cyclophosphamide by regulating cellular immune function and inducing apoptosis in Hepatoma 22 tumor-bearing mice

Fuzheng Qingjie (FZQJ) is a polyherbal Chinese medicine that has previously been implemented as an adjuvant therapy for gastrointestinal cancer. The present study investigated whether FZQJ is able to potentiate the anticancer effect of cyclophosphamide (CTX). Hepatoma 22 tumor-bearing mice were randomly divided into a vehicle group, CTX group, FZQJ group and combination (CTX+FZQJ) group. In addition, untreated mice without H22 cells served as blank controls. Seven days post-treatment, the mice were sacrificed and the tumors were weighed. Blood cells were evaluated using an automatic hemocytometer analyzer and flow cytometer. The expression levels of interleukin (IL)-2 and tumor necrosis factor (TNF)-α were evaluated using a radioimmunoassay. Apoptotic cells were observed using a terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. Alanine transaminase, aspartate aminotransferase, blood urea nitrogen and creatinine were examined using an automatic biochemical analyzer. The results demonstrated that the tumor inhibitory rate and apoptosis index were higher in the combination group, compared with those in the CTX group. Notably, FZQJ was able to alleviate CTX-induced decreases in the numbers of white blood cells and platelets, CD3⁺ and CD4⁺ T lymphocyte subsets, and the concentration of hemoglobin, body weight and thymus index, and increase serum TNF-α and IL-2 levels without overt hepatorenal toxicity. These results suggest that FZQJ granules may enhance the anticancer effect of CTX, in addition to alleviating the side effects.

Bikunin plus paclitaxel markedly reduces tumor burden and ascites in mouse model of ovarian cancer

Our previous studies of intraperitoneal ovarian carcinoma in a mouse model demonstrated that bikunin gene transfection could prevent ascites formation and intraperitoneal disseminated metastasis. Although ascites was almost completely inhibited, tumor burden was variably reduced. Several reports have indicated that bikunin may be involved in tumor survival. In the present study, the effectiveness of exogenous bikunin and the biodistribution characteristics of (125)I-bikunin were initially examined in a mouse model of human ovarian cancer HRA cells. The once-daily i.p. administration of bikunin significantly decreased progressive growth of HRA tumors and ascites formation in a dose-dependent manner. Maximal radioisotope tumor uptake peaked at 7.4% injected dose/g at 3 hr. Bikunin binding specificity was demonstrated by reduced tumor uptake after coinjection of excess nonradioactive bikunin. Bikunin was rapidly excreted renally. The bikunin therapy produced the significant inhibition in expression of the proteolysis (uPA and uPAR) and angiogenesis-related molecules (VEGF and bFGF). The second purpose of our study was to optimize the antimetastatic activity of bikunin in combination with paclitaxel against HRA cells growing orthotopically in mice. The once-daily i.p. administration of bikunin (25 microg/g body weight/day) in combination with paclitaxel (i.p., 100 microg/20 g at days 2 and 5) significantly decreased progressive growth of HRA cells in a synergistic fashion. In conclusion, combination therapy with bikunin plus paclitaxel may be an effective way to markedly reduce i.p. tumor growth and ascites in ovarian carcinoma possibly through suppression of uPA, uPAR, VEGF and bFGF expression.

Vascular endothelial growth factor immunoneutralization plus Paclitaxel markedly reduces tumor burden and ascites in athymic mouse model of ovarian cancer

Ovarian cancer is characterized by rapid growth of solid intraperitoneal tumors and production of large volumes of ascites. Our previous studies of intraperitoneal ovarian carcinoma in an athymic mouse model demonstrated that a monoclonal antibody (mAb) to human vascular endothelial growth factor (VEGF) could prevent ascites formation. Although ascites was almost completely inhibited, tumor burden was variably reduced. To develop more effective therapy, we assessed the combination of a human VEGF mAb plus paclitaxel. Four groups of female athymic nude mice were inoculated intraperitoneally with OVCAR3 cells. Two weeks after inoculation, one group was treated with a human VEGF mAb intraperitoneally twice weekly plus paclitaxel intraperitoneally three times weekly for 6 weeks. The second group was treated with VEGF mAb alone. The third group was treated with paclitaxel alone. The remaining group was treated with vehicle only. Tumor burden in the VEGF mAb plus paclitaxel and paclitaxel alone groups was reduced by 83.3% and 85.7% and 58.5% and 59.5%, respectively, in two separate experiments, compared to controls. VEGF mAb alone caused no significant decrease in tumor burden, nor did treatment of mice inoculated intraperitoneally with HEY-A8 cells, a non-VEGF-secreting ovarian cell line. Virtually no ascites developed in the combined treatment group or the group treated with VEGF mAb alone. Paclitaxel alone reduced ascites slightly, but not significantly. Morphological studies demonstrated that VEGF immunoneutralization enhanced paclitaxel-induced apoptosis in these human ovarian cancers. Thus, combination therapy with inhibitors of VEGF plus paclitaxel may be an effective way to markedly reduce tumor growth and ascites in ovarian carcinoma.

Glutathione concentration may be a useful predictor of response to second-line chemotherapy in patients with ovarian cancer

BACKGROUND

No useful predictor of resistance or sensitivity to second-line chemotherapy is known for ovarian cancer. The objective of this prospective study was to determine the utility of tumor glutathione S-transferase-pi (GST-pi) expression or glutathione (GSH) concentration in predicting ovarian cancer patients' responses to second-line chemotherapy.

METHODS

Tumor samples were obtained from 26 patients with relapsed epithelial ovarian cancer 3-4 weeks before the initiation of second-line chemotherapy with etoposide (daily on Days 1-5) and cisplatin (on Day 5). The expression of GST-pi in tumor samples was determined by immunohistochemical staining and Western blot analysis. GSH concentration was measured by an enzymatic assay.

RESULTS

The response rate was 38.4%. The estimated 3-year survival rate for the responders (66.7%) significantly exceeded that for the nonresponders (9.1%). Expression of GST-pi by immunohistochemical staining was more frequently observed in nonresponders (2 of 10 responders vs. 11 of 16 nonresponders). Western blot analysis detected GST-pi in all cases. There was no significant difference in the relative density values of the GST-pi Western blot analysis between the two groups. The mean value of GSH concentration in nonresponders was significantly higher than in responders (18.4 +/- 9.7 vs. 7.5 +/- 8.2 microg/mg protein). GSH concentration was below the cutoff point (10.3 microg/mg protein) in all responders except one.

CONCLUSIONS

Second-line chemotherapy consisting of etoposide and cisplatin is effective in the treatment of relapsed epithelial ovarian cancer. In addition, tumor concentration of GSH may be a useful predictor of the response to this therapy.

Enhanced topoisomerase I activity and increased topoisomerase II alpha content in cisplatin-resistant cancer cell lines

Although the combined effects of cisplatin (CDDP) and DNA topoisomerase (Topo) inhibitors have been described in recent literature, little is known about the combined effects and their biological basis in CDDP-resistant cells. The aim of the present study was to elucidate the combined effect of CDDP and Topo inhibitors on CDDP-resistant cells as well as to investigate the biological factors involved in the sensitivity to these anti-cancer agents. We found synergistic actions between CDDP and SN-38 (a Topo I inhibitor) or VP-16 (a Topo II inhibitor) in KFr cells, a CDDP-resistant subline of the KF epithelial ovarian carcinoma cell line, but not in the parent KF cells. We subsequently assayed Topo protein levels and enzymatic activities in two sets of CDDP-sensitive and -resistant cell lines: KF and KFr, and HeLa and HeLa/CDDP. The levels of Topo I protein in the CDDP-resistant cells did not differ from those of their parent cell lines and were unaffected by exposure to CDDP. Topo I enzymatic activity, however, was 2- to 4-fold higher in the CDDP-resistant cell lines than in their respective parent cell lines. In contrast, higher levels of Topo II alpha protein were observed both before and after CDDP exposure in the CDDP-resistant cells than in their controls. However, no difference in Topo II catalytic activity was observed between the CDDP-resistant and -sensitive cells.