Treatment of advanced epithelial ovarian cancer: past, present and future

Role of GPX4 inhibition-mediated ferroptosis in the chemoresistance of ovarian cancer to Taxol in vitro

BACKGROUND

Ovarian cancer remains a common gynecological tumor and the fifth leading cause of death worldwide. Taxol-based chemotherapy is a standard approach to the treatment of ovarian cancer. Glutathione peroxidase 4 (GPX4) is the key regulator of ferroptosis, which is an important form of cell death. Here, we investigate the effect of GPX4 inhibition-mediated ferroptosis on the sensitivity of ovarian cancer cells to Taxol.

METHODS AND RESULTS

A2780/PTX and OVCAR-3/PTX Taxol-resistant ovarian cancer cells were established, and stable GPX4 knockout cell lines were generated via lentivirus GPX4-sgRNA. The GPX4 expression level, the apoptosis rate and cell viability were analyzed. The levels of ferroptosis-related factor indicators such as malondialdehyde (MDA) and reactive oxygen species (ROS) were measured. The results showed that the GPX4 protein and mRNA levels were increased in the Taxol-resistant cells. Moreover, GPX4 knockout reduced cell viability and inhibited the colony formation rate. In addition, we found that GPX4 inhibition increased Taxol sensitivity by inducing ferroptosis.

CONCLUSIONS

In summary, our studies reveal that GPX4 inhibition promotes ferroptosis and increases the sensitivity of ovarian cancer cells to Taxol in vitro.

Effects of sequential paclitaxel-carboplatin followed by gemcitabine-based chemotherapy compared with paclitaxel-carboplatin therapy administered to patients with advanced epithelial ovarian cancer: A retrospective, STROBE-compliant study

We aimed to compare the efficacy of paclitaxel and carboplatin followed by gemcitabine-based combination chemotherapy with paclitaxel-carboplatin for treating advanced epithelial ovarian cancer in this retrospective, STROBE-compliant study. Patients' tolerance to treatment was also assessed.We retrospectively analyzed the records of 178 women who underwent initial optimal debulking surgery between January 2003 and December 2011 to treat FIGO stage IIIc epithelial ovarian cancer. Patients in arm 1 (n = 88) received 4 cycles of paclitaxel and carboplatin followed by 2 to 4 cycles of gemcitabine-based combination chemotherapy. Patients in arm 2 (n = 90) received 6 to 8 cycles of paclitaxel and carboplatin. The granulocyte-colony stimulating factor was administered prophylactically to all patients.The median follow-up for both arms was 62 months. Medianprogression-free survival (PFS) between arms 1 and 2 (28 and 19 months [P = 0.003]) as well as 5-year OS (34.1% and 18.9% [P = 0.021]) differed significantly. The neurotoxicity rate was significantly higher in arm 2 than in arm 1 (45.2% vs 27.1%, P = 0.026). There was no significant difference between study arms in hematological toxicity.The sequential regimen significantly improved PFS and 5-year OS with tolerable toxicity compared with the single regimen, and offers an alternative for treating patients with advanced epithelial ovarian cancer.

Phototoxicity of Hemoporfin to ovarian cancer

Hematoporphyrin monomethyl ether (Hemoporfin) is a novel porphyrin-related photosensitizer. Photocytotoxic effect of Hemoporfin to ovarian cancer is still unclear. We used human epithelial ovarian carcinoma cell line SKOV3 and its xenograft model in nude mice to investigate the Hemoporfin-based photodynamic therapy (PDT) for ovarian cancer. The growth rates of SKOV3 cells were determined by MTT assays. Flow cytometry combined with dual Annexin V/PI staining was used to identify the death mode of the cells following PDT. We demonstrated that Hemoprofin-based PDT induced significant cell death via direct necrosis induction, and the photocytotoxity to SKOV3 cells is dose related. With SKOV3 xenograft model in nude mouse, we further demonstrated that Hemoporfin-based PDT is effective for controlling the tumor growth. Our results suggest that Hemoporfin is a promising novel photosensitizer for the treatment of ovarian cancer and merit further evaluation in the clinical practice.

A multicenter phase II study of gemcitabine, paclitaxel, and cisplatin in chemonaïve advanced ovarian cancer

OBJECTIVES

The objectives of this multicenter phase II study were to evaluate the effects of gemcitabine-paclitaxel-cisplatin combination chemotherapy on response rate, survival, and toxicity in patients with advanced epithelial ovarian cancer (AEOC).

METHODS

Chemonaive AEOC patients with bidimensionally measurable disease or an elevated serum cancer antigen 125 level received cisplatin (70 mg/m(2)) on day 1 and paclitaxel (80 mg/m(2)) and gemcitabine (1000 mg/m(2)) on days 1 and 8, every 3 weeks.

RESULTS

Between October 2000 and September 2001, 46 patients were enrolled. Sixteen patients underwent debulking surgery prior to chemotherapy. In 45 evaluable patients, overall response rate was 64.4% (7 CR and 22 PR). Median time-to-progression was 13.4 months (95% CI, 9.6-17.4 months); median progression-free survival was 12.3 months (95% CI, 8.8-15.6 months); median overall survival was 26.0 months (95% CI, 18 months-not reached); and 1-year survival was 74% (95% CI, 60-88%). The relative dose intensities of gemcitabine, paclitaxel, and cisplatin were 81.4%, 80.2%, and 89.8%, respectively. Grade 3/4 neutropenia was the predominant hematologic toxicity observed (73.9% of patients) followed by grade 3/4 leukopenia (56.5%), anemia (45.7%), thrombocytopenia (23.9%), and febrile neutropenia/neutropenic sepsis (26.1%). The predominant grade 3 nonhematologic toxicities were alopecia (43.5%) and diarrhea (19.6%). Grade 4 nonhematologic toxicities were nausea/vomiting, constipation, and uremia (2.2% each). Two treatment-related deaths occurred (neutropenic sepsis and uremia).

CONCLUSION

Gemcitabine-paclitaxel-cisplatin combination chemotherapy is active with manageable toxicity in chemonaive patients with advanced ovarian cancer and should be explored in larger phase III trials.

Phase II feasibility study of sequential couplets of Cisplatin/Topotecan followed by paclitaxel/cisplatin as primary treatment for advanced epithelial ovarian cancer: a National Cancer Institute of Canada Clinical Trials Group Study

PURPOSE

Despite the improved results in advanced ovarian cancer achieved with the addition of paclitaxel to frontline therapy, there remains room for improvement. One approach is to add new agents such as topotecan. Because myelosuppression limits the delivery of topotecan with paclitaxel/cisplatin in a three-drug combination, we explored giving sequential couplets of cisplatin/topotecan followed by paclitaxel/cisplatin.

PATIENTS AND METHODS

Forty-four patients with residual epithelial ovarian carcinoma after primary surgery were studied. Cisplatin 50 mg/m(2) on day 1 and topotecan 0.75 mg/m(2) on days 1 through 5 were administered at 21-day intervals for four cycles, followed by interval debulking surgery (if optimal debulking was not achieved with primary surgery), and then paclitaxel 135 mg/m(2) over 24 hours on day 1 and cisplatin 75 mg/m(2) on day 2 at 21-day intervals for four cycles.

RESULTS

Such sequential couplets are feasible. Myelotoxicity was the major toxic effect, but it was of short duration. The granulocyte nadir with topotecan/cisplatin occurred late (median, day 18), so retreatment on day 21 was not always possible. There was no unexpected nonhematologic toxicity. The regimen was active in this group of patients who had undergone largely suboptimal debulking surgery. In 34 patients with clinically measurable disease, the overall response rate was 78%, and 30 (77%) of the 39 patients with elevated CA 125 levels at baseline had normalization of CA 125 levels by the end of therapy.

CONCLUSION

Sequential couplets of cisplatin/topotecan followed by paclitaxel/cisplatin are feasible. The efficacy data in this suboptimal group of patients has encouraged us to proceed with a randomized study based on this approach.