When nonplatinum is the answer: the role of trabectedin plus pegylated liposomal doxorubicin in recurrent ovarian cancer

Trabectedin in Cancers: Mechanisms and Clinical Applications

Trabectedin, a tetrahydroisoquinoline alkaloid, is the first marine antineoplastic agent approved with special anticancer mechanisms involving DNA binding, DNA repair pathways, transcription regulation and regulation of the tumor microenvironment. It has favorable clinical applications, especially for the treatment of patients with advanced soft tissue sarcoma, who failed in anthracyclines and ifosfamide therapy or could not receive these agents. Currently, trabectedin monotherapy regimen and regimens of combined therapy with other agents are both widely used for the treatment of malignancies, including soft tissue sarcomas, ovarian cancer, breast cancer, and non-small-cell lung cancer. In this review, we summarized the basic information and some updated knowledge on trabectedin, including its molecular structure, metabolism in various cancers, pharmaceutical mechanisms, clinical applications, drug combination, and adverse reactions, along with prospections on its possibly more optimal use in cancer treatment.

Trabectedin (Yondelis®) as a Therapeutic Option in Gynecological Cancers: A Focus on its Mechanisms of Action, Clinical Activity and Genomic Predictors of Drug Response

The use of predictive biomarkers provides potential individualized cancer therapeutic options to prevent therapy failure as well as serious toxicities. Several recent studies showed that predictive and prognostic biomarkers are a notable personalized strategy to improve patients' care in several cancers. Trabectedin (Yondelis®) is a cytotoxic agent, derived from a marine organism, harbouring a significant antitumor activity against several cancers such as soft tissue sarcoma, ovarian, and breast cancers. Recently and with the advent of molecular genetic testing, BRCA mutational status was found as an important predictor of response to this anticancer drug, especially in gynecological cancers. The aim of this updated review is to discuss the mechanisms of action of trabectedin against the wellknown cancer hallmarks described until today. The current advances were also examined related to genomic biomarkers that can be used in the future to predict the efficacy of this potent anticancer natural molecule in various gynecological cancers.

Real-world experience with trabectedin for the treatment of recurrent ovarian cancer

Introduction: The efficacy and safety of trabectedin/pegylated liposomal doxorubicin (trabectedin/PLD) in patients with recurrent ovarian cancer have been demonstrated in randomized clinical studies. Real-world evidence is a subsequent necessary step for completing information from clinical practice. In the case of trabectedin/PLD, this evidence derives from prospective studies, retrospective analyses, and case series.Areas covered: The present narrative review provides the most relevant data about efficacy and safety of trabectedin/PLD in real-world studies, and the interpretation of the experience with trabectedin/PLD in clinical practice for patients with recurrent ovarian cancer.Expert opinion: Trabectedin/PLD has a proven antitumor activity that is maintained when administered in advanced lines. Trabectedin/PLD in patients who have relapsed between 6 and 12 months have showed comparable survival outcomes than platinum-based regimens. Moreover, the administration of trabectedin/PLD was associated with a positive survival trend after two previous platinum lines and a significantly superior PFS after subsequent platinum-based therapy. Additionally, the activity of trabectedin seems to be increased in patients with BRCA-mutated ovarian cancer. Overall, real-word evidence has confirmed that trabectedin/PLD is an effective and safe non-platinum combination for advanced lines of chemotherapy in patients with platinum-sensitive recurrent ovarian cancer.

Managing recurrent ovarian cancer in daily clinical practice: case studies and evidence review with a focus on the use of trabectedin

Following the failure of first-line platinum-based chemotherapy in ovarian cancer, options for further therapy in potentially platinum-responsive patients are: carboplatin doublets with pegylated liposomal doxorubicin, gemcitabine or paclitaxel in association with bevacizumab, followed by maintenance with bevacizumab (for nonpretreated patients); or maintenance monotherapy with a poly(ADP-ribose) polymerase inhibitor after a response. The choice of biological therapy depends on a patient’s previous treatments and priority for a symptomatic response. In cases of a rapidly growing tumor or need for symptomatic relief, the addition of bevacizumab should be considered. Patients with limited potential sensitivity to platinum, such as those with a platinum treatment-free interval of 6–12 months, may benefit from intercalation with trabectedin and pegylated liposomal doxorubicin to possibly restore platinum sensitivity.

Brain Metastases from Ovarian Cancer: Current Evidence in Diagnosis, Treatment, and Prognosis

With this review, we provide the state of the art concerning brain metastases (BMs) from ovarian cancer (OC), a rare condition. Clinical, pathological, and molecular features, treatment options, and future perspectives are comprehensively discussed. Overall, a diagnosis of high-grade serous OC and an advanced disease stage are common features among patients who develop brain metastases. BRCA1 and BRCA2 gene mutations, as well as the expression of androgen receptors in the primary tumor, are emerging risk and prognostic factors which could allow one to identify categories of patients at greater risk of BMs, who could benefit from a tailored follow-up. Based on present data, a multidisciplinary approach combining surgery, radiotherapy, and chemotherapy seem to be the best approach for patients with good performance status, although the median overall survival (<1 year) remains largely disappointing. Hopefully, novel therapeutic avenues are being explored, like PARP inhibitors and immunotherapy, based on our improved knowledge regarding tumor biology, but further investigation is warranted.

Exonuclease 1 (Exo1) Participates in Mammalian Non-Homologous End Joining and Contributes to Drug Resistance in Ovarian Cancer

Background

Exonuclease 1 (Exo1) participates in a variety of DNA damage repair, including mismatch repair, nucleotide excision repair, and homologous recombination. Genetic study in yeast indicates a role of Exo1 in non-homologous end joining (NHEJ), acting as a regulator for accuracy repairing DNA. This study aimed to investigate the effects of human Exo1 in NHEJ and drug resistance in ovarian cells.

Material/Methods

Ectopic expression of Exo1 was carried out using pcDNA3.1-EXO1 plasmid in SKOV3 cells. GST-tagged human Exo1 was purified using pTXB1-gst-EXO1 and the his-tagged-Ku was collected using pET15b.his.Ku. Exo1 and Ku70 proteins expressed in bacteria were harvested and purified. DNA-protein binding was examined using affinity capture assay. The cells were treated using drugs for 72 hours. Then, the viabilities of cells were evaluated with sulforhodamine B cell viability analysis. The protein expression was evaluated using western blot assay.

Results

As expected, human cells that deficient of Exo1 were sensitive to ionizing radiation and DNA damaging drugs (cisplatin and doxorubicin). Cisplatin resistant ovarian cancer cell line and Exo1 deficient cell lines were successfully generated. Exo1 interacts with NHEJ required factor Ku70 and affects NHEJ efficiency. We observed that Exo1 expression level was upregulated in drug resistant cell line and knockdown of Exo1 in drug resistant cells sensitized cells to cisplatin and doxorubicin.

Conclusions

Exo1 participated in mammalian non-homologous end joining and contributed to drug resistance in ovarian cancer.