Novel treatment options in platinum-sensitive recurrent ovarian cancer: A review

A comprehensive comparison of PARP inhibitors as maintenance therapy in platinum-sensitive recurrent ovarian cancer: a systematic review and network meta-analysis

BACKGROUND

PARP inhibitors (PARPis) have shown promising effectiveness for ovarian cancer. This network meta-analysis (PROSPERO registration number CRD42024503390) comprehensively evaluated the effectiveness and safety of PARPis in platinum-sensitive recurrent ovarian cancer (PSROC).

METHODS

Articles published before January 6, 2024 were obtained from electronic databases. The study assessed and compared survival outcomes including overall survival (OS), progression-free survival (PFS), second progression-free survival (PFS2), time to first subsequent treatment (TFST), time to second subsequent treatment (TSST), and chemotherapy-free interval (CFI). Additionally, safety outcomes were investigated, specifically focusing on grade 3-4 treatment-emergent adverse effects (TEAEs). The evaluation of OS and PFS was also conducted based on the BRCA and HRD (homologous recombination deficiency) statuses.

RESULTS

Six randomized controlled trials were examined and the four PARPis (olaparib, niraparib, rucaparib and fuluzolparib) have been found to significantly increase the PFS in entire population as well as in subgroups of HRD and BRCAm (BRCA mutation). Only olaparib demonstrated a substantial improvement in OS compared to placebo in entire population (hazard ratio [HR] 0.73; 95% confidence interval [CI] 0.60-0.90), as well as in the subgroup of BRCAm. All analyzed PARPis had significant efficacy in prolonging PFS2, TFST, TSST and CFI. For safety concerns, PARPis could significantly increase incidence of TEAEs (grade3-4), while olaparib had least haematological TEAEs (grade3-4) events compared to other PARPis.

CONCLUSION

All included PARPis showed various degrees of benefit in survival outcomes and safety profile was acceptable for PSROC patients. Among them olaparib had the best performance in both efficacy and safety.

Efficacy and safety of anti-angiogenic drugs combined with chemotherapy in the treatment of platinum-sensitive/resistant ovarian cancer: a meta-analysis with trial sequential analysis of randomized controlled trials

Background

With the emergence of new anti-angiogenic treatments and the ongoing updates to clinical guidelines, the effectiveness and safety of these agents in treating platinum-sensitive/resistant ovarian cancer (OC) are yet to be fully determined. Therefore, we conducted a meta-analysis to evaluate the efficacy and safety of anti-angiogenic drugs combined with chemotherapy (CT) for platinum-sensitive OC (PSOC) or platinum-resistant OC (PROC).

Methods

A comprehensive literature search was conducted across several databases, including PubMed, Web of Science, Embase, and the Cochrane Library, encompassing all pertinent randomized controlled trials (RCTs) up to 31 May 2024. The primary outcomes for the meta-analysis were progression-free survival (PFS) and overall survival (OS), while the objective response rate (ORR), adverse events (AEs) of any grade, and grade ≥3 AEs were considered secondary endpoints. Data synthesis involved the computation of hazard ratio (HR), relative risk (RR), along with their 95% confidence interval (CI) and prediction interval (PI). Trial sequential analysis was carried out using STATA 12.0, R software 4.3.1, and TSA v0.9.5.10 Beta software.

Results

This meta-analysis encompassed 15 RCTs. The overall analysis revealed that compared to CT alone (or plus placebo), anti-angiogenic drugs combined with CT significantly improved PFS (HR [95% CI] = 0.573 [0.518-0.633], 95% PI: 0.383-0.876) and ORR (RR [95% CI] = 1.362 [1.260-1.472], 95% PI: 0.824-2.251), but also increased the incidence of grade ≥3 AEs (RR [95% CI] = 1.115 [1.070-1.162], 95% PI: 0.870-1.422) in PSOC patients. For PROC patients, this combination therapy notably improved PFS (HR [95% CI] = 0.542 [0.475-0.619], 95% PI: 0.322-0.930), OS (HR [95% CI] = 0.752 [0.646-0.875], 95% PI: 0.554-0.997), and ORR (RR [95% CI] = 2.141 [1.702-2.694], 95% PI: 0.839-5.307), whilst simultaneously elevating the risk of grade ≥3 AEs (RR [95% CI] = 1.487 [1.216-1.819], 95% PI: 0.755-2.828).

Conclusion

Our research verified the advantages of combining anti-angiogenic agents with CT in enhancing PFS and ORR for patients with PSOC, and also confirmed improvements in PFS, OS, and ORR for those with PROC. It is crucial for medical practitioners to remain alert to the potential occurrence of AEs when implementing this combined therapeutic approach in a clinical milieu.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42024552010.

Efficacy and safety of anti-angiogenic drug monotherapy and combination therapy for ovarian cancer: a meta-analysis and trial sequential analysis of randomized controlled trials

Background

As the development of novel anti-angiogenic drugs and the continuous evolution of guideline recommendations, the efficacy and safety of anti-angiogenic agents in ovarian cancer (OC) remains unclear. Consequently, a meta-analysis was carried out to assess the efficacy and safety of anti-angiogenic drug monotherapy and combination therapy for OC.

Methods

An exhaustive literature review was performed across multiple databases, including PubMed, Embase, Web of Science, and Cochrane, encompassing all relevant randomized controlled trials (RCTs) up until 6 April 2024. The evaluation of efficacy outcomes incorporated progression-free survival (PFS), overall survival (OS), and objective response rate (ORR). Safety was assessed through the occurrence of any grade adverse events (AEs) and grade ≥3 AEs. Synthesis of the data involved the calculation of hazard ratios (HRs), relative risks (RRs), and their corresponding 95% confidence intervals (CIs) and prediction intervals (PIs). Trial sequential analysis was executed employing TSA v0.9.5.10 Beta software, STATA 12.0, and R software 4.3.1.

Results

In this meta-analysis, 35 RCTs were included, encompassing 16,199 subjects in total. The overall analysis indicated that anti-angiogenic drug combination therapy significantly improved PFS (HR [95% CI] = 0.678 [0.606-0.759], 95% PI: 0.415-1.108), OS (HR [95% CI] = 0.917 [0.870-0.966], 95% PI: 0.851-0.984), and ORR (RR [95% CI] = 1.441 [1.287-1.614], 95% PI: 1.032-2.014), but also increased the incidence of grade ≥3 AEs (RR [95% CI] = 1.137 [1.099-1.177], 95% PI: 1.011-1.252). The analysis did not corroborate any benefit of anti-angiogenic monotherapy over placebo concerning PFS (HR [95% CI] = 0.956 [0.709-1.288], 95% PI: 0.345-2.645) and OS (HR [95% CI] = 1.039 [0.921-1.173], 95% PI: 0.824-1.331). However, it was observed that monotherapy with anti-angiogenic drugs did increase the incidence of any grade AEs (RR [95% CI] = 1.072 [1.036-1.109], 95% PI: 0.709-1.592).

Conclusion

Our study confirmed the PFS, OS, and ORR benefits of anti-angiogenic drug combination therapy for OC patients. The efficacy results of anti-angiogenic monotherapy necessitates further evaluation as more RCTs become available. Clinicians should be vigilant of AEs when administering anti-angiogenic agents in a clinical setting.

Efficacy and safety of PARP inhibitors for maintenance treatment of ovarian cancer, regardless of BRCA or HRD status: a comprehensive updated meta-analysis

Without taking into account existing biomarkers like genetic mutations (BRCA mutation, Homologous recombination deficiency) with advanced ovarian cancer (OC), the overall survival (OS), progress-free survival (PFS) of the aggregate all groups that have been classified were hazard ratio (HR): 0.72, 95% confidence intervals (CI): 0.66-0.79 and HR: 0.48, 95%CI: 0.44-0.52, respectively. Meanwhile, the OS and PFS of the whole population (regardless of existing genetic mutation markers) were HR: 0.74, 95%CI: 0.64-0.87 and HR: 0.52, 95%CI: 0.42-0.65, separately. Furthermore, the OS and PFS of positive gene mutation markers were HR: 0.71, 95%CI: 0.61-0.83 (HRD and BRACm) and HR: 0.47, 95%CI: 0.42-0.52 (HRD and BRACm), individually. The poly ADP-ribose polymers (PARP) inhibitors have desired efficiency and security in the maintenance treatment of advanced OC patients with BRCAm or BRCAwt, HRD or HRP and unknown gene status.

Synthesis and anti-ovarian cancer effects of benzimidazole-2-substituted pyridine and phenyl propenone derivatives

Background: Given the benzimidazole derivatives have anti-ovarian cancer effects, the authors aimed to determine whether benzimidazole-2-substituted pyridine and phenyl propenone derivatives exert anti-ovarian cancer activity. Materials & methods: 21 derivatives were synthesized and assayed for their antiproliferative activities. Western blotting in A2780 cells was used to detect the effects of compound A-6 on apoptosis-related proteins. Invasion, migration and apoptosis were assayed in SKOV3 cells treated with A-6. The in vivo activity was also examined. Results: A-6 could inhibit proliferation, invasion and migration and induce apoptosis in SKOV3 cells. Additionally, A-6 had potent inhibitory activity in a xenograft mouse model. Conclusion: A-6 shows potent efficacy in the treatment of ovarian cancer and may be a potential antitumor agent.

Therapy for Recurrent High-Grade Epithelial Ovarian Cancer—The Current Status and Future Trends

Ovarian malignancy is the seventh most frequently diagnosed cancer among women. The most common type is epithelial ovarian cancer. Several subtypes with distinct biological and molecular properties exist, and there is inconsistency in availability of and access to different modalities of treatment. The standard first-line management is combining surgery and platinum-based chemotherapy. Most of them are diagnosed at an advanced stage due to which they have poor outcomes. The existing screening tests have a low predictive value. Even with the best available upfront treatment, high rates of recurrences are observed. As a result, there have been major advances in the treatment of recurrences with the development of anti-angiogenic agents and PARP inhibitors. It has led to the improvement in survival and quality of life among the relapsed epithelial ovarian cancers. This review is focused on the management of recurrent epithelial ovarian cancers and future directions based on current evidence. The application of a personalized and structured approach will meaningfully bring changes in the paradigm of care in these groups of patients.

UBE2T regulates epithelial–mesenchymal transition through the PI3K-AKT pathway and plays a carcinogenic role in ovarian cancer

Background

Ubiquitin-binding enzyme E2T (UBE2T), a member of the E2 family of the ubiquitin–proteasome pathway, is associated with tumorigenesis of varioustumours; however, its role and mechanism in ovarian cancer remain unclear.

Results

Our study revealed that UBE2T is highly expressed in ovarian cancer; this high expression was closely related to poor prognosis. Immunohistochemistry was used to validate the high expression of UBE2T in ovarian cancer. This is the first study to demonstrate that UBE2T expression is higher in ovarian cancer with BRCA mutation. Moreover, we demonstrated that UBE2T gene silencing significantly inhibited ovarian cancer cell proliferation and invasion. The epithelial–mesenchymal transition (EMT) of ovarian cancer cells and phosphatidylinositol 3 kinase/protein kinase B (PI3K-AKT) pathway were significantly inhibited. Adding the mechanistic target of rapamycin activator MHY1485 activated the PI3K-AKT pathway and significantly restored the proliferative and invasive ability of ovarian cancer cells. Furthermore, a tumorigenesis experiment in nude mice revealed that tumour growth on mice body surface and tumour tissue EMT were significantly inhibited after UBE2T gene silencing.

Conclusions

This study demonstrated that UBE2T regulates EMT via the PI3K-AKT pathway and plays a carcinogenic role in ovarian cancer. Moreover, UBE2T may interact with BRCA to affect ovarian cancer occurrence and development. Hence, UBE2T may be a valuable novel biomarker for the early diagnosis and prognosis and treatment of ovarian cancer. Further, UBE2T inhibition may be effective for treating ovarian cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-022-01034-9.

Successful secondary radical operation on unretractable metastatic platinum-sensitive recurrent ovarian cancer by immunotherapy: a case report

Background

Although rechallenge with platinum-based chemotherapy is effective for most platinum-sensitive recurrent ovarian cancer (ROC) patients, there is still a subset of patients who have no responses to the standard care. Overcoming multidrug resistance (MDR) is a top priority in oncology clinics, but it remains intricate. It is difficult for clinicians to manage unretractable ROC when conventional therapy yields no results. The rational and effective use of immunotherapy will contribute to the clinical benefit of these patients, especially in patients without approved immunotherapy biomarkers. Here we present a case of successful secondary radical surgery for unretractable metastatic MDR ROC by immunotherapy based on her immune-infiltrating tumor microenvironment signatures.

Case Description

A 57-year-old woman, diagnosed with IC2 stage high-grade serous ovarian cancer in 2015, underwent immediate ultra-radical cytoreductive surgery followed by 6 cycles of platinum-containing adjuvant chemotherapy. After nearly 37 months of disease-free status, the woman complained of spontaneous pain from the right subcostal margin for 1 month and was diagnosed with ROC accompanied by multiple unretractable colorectal and hepatic metastases. Standard chemotherapies were ineffective and quickly resulted in disease progression and grade IV myelosuppression followed impaired gastrointestinal function. Notably, after standard chemotherapy, the patient was tested negative for all immune biomarkers, but multiple fluorescence immunohistochemistry indicated that her tumor tissue was significantly infiltrated with the cluster of differentiation 8 (CD8) T cells and natural killer (NK) cells, implying potential benefits of immunotherapy. Then changed to 3 cycles of intravenous pembrolizumab, the main pelvic tumor and hepatic metastases showed significant shrinkage and achieved partial response, but the disease progressed after 8.7 months. Subsequently, arterial perfusion with pembrolizumab was performed combined with the chemotherapy. A comfortingly partial response was achieved again that enabled the patient to successfully undergo a secondary radical surgery for colorectal and liver metastases. Since that time the patient’s postoperative course has been favorable, and she remains disease-free at present for at least 17 months.

Conclusions

Immune infiltration signatures of the tumor microenvironment could serve as an indication for immunotherapy in patients with unretractable platinum-sensitive ROC with MDR. In addition, the introduction of immunotherapy might bring some degree of chemotherapy resensitization.

The targeted SMAC mimetic SW IV-134 augments platinum-based chemotherapy in pre-clinical models of ovarian cancer

Background

Ovarian cancer is initially responsive to frontline chemotherapy. Unfortunately, it often recurs and becomes resistant to available therapies and the survival rate for advanced and recurrent ovarian cancer is unacceptably low. We thus hypothesized that it would be possible to achieve more durable treatment responses by combining cisplatin chemotherapy with SW IV-134, a cancer-targeted peptide mimetic and inducer of cell death. SW IV-134 is a recently developed small molecule conjugate linking a sigma-2 ligand with a peptide analog (mimetic) of the intrinsic death pathway activator SMAC (second-mitochondria activator of caspases). The sigma-2 receptor is overexpressed in ovarian cancer and the sigma-2 ligand portion of the conjugate facilitates cancer selectivity. The effector portion of the conjugate is expected to synergize with cisplatin chemotherapy and the cancer selectivity is expected to reduce putative off-target toxicities.

Methods

Ovarian cancer cell lines were treated with cisplatin alone, SW IV-134 alone and a combination of the two drugs. Treatment efficacy was determined using luminescent cell viability assays. Caspase-3/7, − 8 and − 9 activities were measured as complementary indicators of death pathway activation. Syngeneic mouse models and patient-derived xenograft (PDX) models of human ovarian cancer were studied for response to SW IV-134 and cisplatin monotherapy as well as combination therapy. Efficacy of the therapy was measured by tumor growth rate and survival as the primary readouts. Potential drug related toxicities were assessed at necropsy.

Results

The combination treatment was consistently superior in multiple cell lines when compared to the single agents in vitro. The expected mechanism of tumor cell death, such as caspase activation, was confirmed using luminescent and flow cytometry-based assay systems. Combination therapy proved to be superior in both syngeneic and PDX-based murine models of ovarian cancer. Most notably, combination therapy resulted in a complete resolution of established tumors in all study animals in a patient-derived xenograft model of ovarian cancer.

Conclusions

The addition of SW IV-134 in combination with cisplatin chemotherapy represents a promising treatment option that warrants further pre-clinical development and evaluation as a therapy for women with advanced ovarian cancer.

Aberrant expression of TMEM205 signaling promotes platinum resistance in ovarian cancer: An implication for the antitumor potential of DAP compound

INTRODUCTION

TMEM205 is a novel transmembrane protein associated with platinum resistance (PR) in epithelial ovarian carcinoma (OC), however, the specific mechanisms associated with this resistance remain to be elucidated.

METHODS

TMEM205 expression was evaluated in platinum-sensitive (PS) versus platinum resistant (PR) ovarian cancer cell lines and patient serum/tissues. Exosomal efflux of platinum was evaluated with inductively coupled plasma mass spectrometry (ICP-MS) after pre-treatment with small molecule inhibitors (L-2663/L-2797) of TMEM205 prior to treatment with platinum. Cytotoxicity of combination treatment was confirmed in vitro and in an in vivo model.

RESULTS

TMEM205 expression was 10-20 fold higher in PR compared to PS ovarian cancer cell lines, serum samples, and tissues. Co-localization with CD1B was confirmed by in-situ proximity ligation assay suggesting that TMEM205 may mediate PR via the exosomal pathway. Exosomal secretion was significantly increased 5-10 fold in PR cell lines after treatment with carboplatin compared to PS cell lines. Pre-treatment with L-2663 prior to carboplatin resulted in significantly increased intracellular concentration of fluorescently-labeled cisplatin and decreased exosomal efflux of platinum. Decreased cell survival and tumor growth in vitro and in vivo was observed when PR cells were treated with a combination of L-2663 with carboplatin compared to carboplatin alone.

CONCLUSION

TMEM205 appears to be involved in the development of PR in ovarian cancer through the exosomal efflux of platinum agents. This study provides pre-clinical evidence that TMEM205 could serve as a possible biomarker for PR as well as a therapeutic target in combination with platinum agents.

MicroRNAs as Biomarkers for Early Diagnosis, Prognosis, and Therapeutic Targeting of Ovarian Cancer

Ovarian cancer is the major cause of gynecologic cancer-related mortality. Regardless of outstanding advances, which have been made for improving the prognosis, diagnosis, and treatment of ovarian cancer, the majority of the patients will die of the disease. Late-stage diagnosis and the occurrence of recurrent cancer after treatment are the most important causes of the high mortality rate observed in ovarian cancer patients. Unraveling the molecular mechanisms involved in the pathogenesis of ovarian cancer may help find new biomarkers and therapeutic targets for ovarian cancer. MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression, mostly at the posttranscriptional stage, through binding to mRNA targets and inducing translational repression or degradation of target via the RNA-induced silencing complex. Over the last two decades, the role of miRNAs in the pathogenesis of various human cancers, including ovarian cancer, has been documented in multiple studies. Consequently, these small RNAs could be considered as reliable markers for prognosis and early diagnosis. Furthermore, given the function of miRNAs in various cellular pathways, including cell survival and differentiation, targeting miRNAs could be an interesting approach for the treatment of human cancers. Here, we review our current understanding of the most updated role of the important dysregulation of miRNAs and their roles in the progression and metastasis of ovarian cancer. Furthermore, we meticulously discuss the significance of miRNAs as prognostic and diagnostic markers. Lastly, we mention the opportunities and the efforts made for targeting ovarian cancer through inhibition and/or stimulation of the miRNAs.

Real-world treatment patterns of maintenance therapy in platinum-sensitive recurrent ovarian cancer

OBJECTIVES

The clinical utility of maintenance therapy (MT) for patients with platinum-sensitive recurrent ovarian cancer has been validated in several clinical trials. We assessed "real-world" treatment patterns using an electronic health record (EHR) database.

METHODS

A retrospective study of patients diagnosed with ovarian cancer between January 1, 2011 and July 31, 2019 was conducted using the US nationwide Flatiron Health (EHR)-derived de-identified database. Patients were included if they received second- or third-line (2 L or 3 L) platinum-based chemotherapy (PBCT). Information regarding biomarker status was obtained.

RESULTS

2292 patients with ovarian cancer received at least two lines of therapy. 222 patients completed PBCT on or after March 1, 2017 and had ≥2 months of active surveillance or received MT with poly(adenosine diphosphate-ribose) polymerase inhibitors (PARPi) or bevacizumab. 46 (20%) had BRCA mutations (BRCAm), 132 (59%) had a wildtype BRCA (BRCAwt) gene, and 47 (21%) were unknown. Of patients with BRCAm, 63% received a PARPi, 17% received bevacizumab, and 20% underwent active surveillance. Of patients with BRCAwt, 40% received a PARPi, 23% received bevacizumab, and 36% underwent active surveillance. MT was more common in those with younger age and a BRCA mutation. PARPi use increased on average by 1.3% every 3 months (p = .02) with no statistically significant change in use of bevacizumab.

CONCLUSIONS

In this real-world population, MT is becoming progressively more common following 2 L or 3 L PBCT regardless of biomarker status. The results provide insight into the shifting treatment patterns for patients with recurrent ovarian cancer.

Deregulation of Exo70 Facilitates Innate and Acquired Cisplatin Resistance in Epithelial Ovarian Cancer by Promoting Cisplatin Efflux

Simple Summary

Innate and acquired platinum resistance are the leading causes of epithelial ovarian cancer (EOC) mortality. However, the mechanisms remain elusive. Here we found that Exo70, a key subunit of the exocyst, is upregulated in EOC and promotes cisplatin efflux to facilitate innate resistance. More interestingly, cisplatin could downregulate Exo70 to sustain cell sensitivity. However, this function was hampered during prolonged cisplatin treatment, which in turn stabilized Exo70 to facilitate the acquired cisplatin resistance of EOC cells. Our study potentiates Exo70 as a promising target to overcome cisplatin resistance in EOC.

Abstract

Whilst researches elucidating a diversity of intracellular mechanisms, platinum-resistant epithelial ovarian cancer (EOC) remains a major challenge in the treatment of ovarian cancer. Here we report that Exo70, a key subunit of the exocyst complex, contributes to both innate and acquired cisplatin resistance of EOC. Upregulation of Exo70 is observed in EOC tissues and is related to platinum resistance and progression-free survival of EOC patients. Exo70 suppressed the cisplatin sensitivity of EOC cells through promoting exocytosis-mediated efflux of cisplatin. Moreover, cisplatin-induced autophagy-lysosomal degradation of Exo70 protein by modulating phosphorylation of AMPK and mTOR, thereby reducing the cellular resistance. However, the function was hampered during prolonged cisplatin treatment, which in turn stabilized Exo70 to facilitate the acquired cisplatin resistance of EOC cells. Knockdown of Exo70, or inhibiting exocytosis by Exo70 inhibitor Endosidin2, reversed the cisplatin resistance of EOC cells both in vitro and in vivo. Our results suggest that Exo70 overexpression and excessive stability contribute to innate and acquired cisplatin resistance through the increase in cisplatin efflux, and targeting Exo70 might be an approach to overcome cisplatin resistance in EOC treatment.

The lncRNA 'UCA1' modulates the response to chemotherapy of ovarian cancer through direct binding to miR-27a-5p and control of UBE2N levels

Ovarian cancer (OC) is the leading cause of death in patients with gynecologic cancers. Due to late diagnosis and resistance to chemotherapy, the 5‐year survival rate in patients with OC is below 40%. We observed that UCA1, a lncRNA previously reported to play an oncogenic role in several malignancies, is overexpressed in the chemoresistant OC cell line OAW42‐R compared to their chemotherapy‐sensitive counterpart OAW42. Additionally, UCA1 overexpression was related to poor prognosis in two independent patient cohorts. Currently, the molecular mechanisms through which UCA1 acts in OC are poorly understood. We demonstrated that downregulation of the short isoform of UCA1 sensitized OC cells to cisplatin and that UCA1 acted as competing endogenous RNA to miR‐27a‐5p. Upon UCA1 downregulation, miR‐27a‐5p downregulated its direct target UBE2N leading to the upregulation of BIM, a proapoptotic protein of the Bcl2 family. The upregulation of BIM is the event responsible for the sensitization of OC cells to cisplatin. In order to model response to therapy in patients with OC, we used several patient‐derived organoid cultures, a model faithfully mimicking patient’s response to therapy. Inhibition of UBE2N sensitized patient‐derived organoids to platinum salts. In conclusion, response to treatment in patients with OC is regulated by the UCA1/miR‐27a‐5p/UBE2N axis, where UBE2N inhibition could potentially represent a novel therapeutic strategy to counter chemoresistance in OC.

Strategies for the Improvement of Metal-Based Chemotherapeutic Treatments

This article provides an overview of the various research approaches we have explored in recent years to improve metal-based agents for cancer or infection treatments. Although cisplatin, carboplatin, and oxaliplatin remain the cornerstones in tumor chemotherapy, the discovery and approval of novel inorganic anticancer drugs is a very slow process. Analogously, although a few promising inorganic drugs have found clinical application against parasitic or bacterial infections, their use remains relatively limited. Moreover, the discovery process is often affected by small therapeutic enhancements that are not attractive for the pharmaceutical industry. However, the availability of increasing mechanistic information for the modes of action of established inorganic drugs is fueling the exploration of various approaches for developing effective inorganic chemotherapy agents. Through a series of examples, some from our own research experience, we focus our attention on a number of promising strategies, including (1) drug repurposing, (2) the simple modification of the chemical structures of approved metal-based drugs, (3) testing novel drug combinations, and (4) newly synthesized complexes coupling different anticancer drugs. Accordingly, we aim to suggest and summarize a series of reliable approaches that are exploitable for the development of improved and innovative treatments.

Real-world experience of olaparib as maintenance therapy in BRCA-mutated recurrent ovarian cancer

PURPOSE

The primary objective of our study was to investigate the effectiveness and safety of olaparib maintenance therapy in patients with BRCA-mutated recurrent ovarian cancer in daily practice. The secondary objective of this study was to identify prognostic factors associated with prolonged progression-free survival (PFS) in such patients.

METHODS

We conducted a retrospective analysis of 40 patients who received olaparib maintenance treatment. Data on clinicopathological factors, oncological outcomes, and adverse events were obtained from medical records and analyzed.

RESULTS

All patients had high-grade serous recurrent ovarian cancer with BRCA mutation and achieved complete or partial response to the most recent platinum-based chemotherapy. After a median follow-up of 14.3 months, the median PFS was 23.7 months (95% confidence interval, 14.1-33.4); however, the median overall survival was not reached. In the log-rank test, the PFS was significantly longer for patients with most recent platinum-free interval (PFI) ≥ 12 months, complete response to the last platinum-based chemotherapy, and less than three lines of previous chemotherapy (p = 0.005, p = 0.016, and p = 0.023, respectively). Most hematologic and non-hematologic adverse events were of grade 1 or 2, and the common adverse events were mostly related to myelosuppression.

CONCLUSION

Olaparib maintenance treatment in BRCA-mutated recurrent ovarian cancer is effective and safe in clinical practice. Most recent PFI, response to the last platinum-based chemotherapy, and the number of previous chemotherapy lines were associated with PFS in patients with BRCA-mutated recurrent ovarian cancer.

Theasaponin E1 Inhibits Platinum-Resistant Ovarian Cancer Cells through Activating Apoptosis and Suppressing Angiogenesis

Novel therapeutic strategies for ovarian cancer treatment are in critical need due to the chemoresistance and adverse side effects of platinum-based chemotherapy. Theasaponin E₁ (TSE1) is an oleanane-type saponin from Camellia sinensis seeds. Its apoptosis-inducing, cell cycle arresting and antiangiogenesis activities against platinum-resistant ovarian cancer cells were elucidated in vitro and using the chicken chorioallantoic membrane (CAM) assay. The results showed that TSE1 had more potent cell growth inhibitory effects on ovarian cancer OVCAR-3 and A2780/CP70 cells than cisplatin and was lower in cytotoxicity to normal ovarian IOSE-364 cells. TSE1 significantly induced OVCAR-3 cell apoptosis via the intrinsic and extrinsic apoptotic pathways, slightly arresting cell cycle at the G2/M phase, and obviously inhibited OVCAR-3 cell migration and angiogenesis with reducing the protein secretion and expression of vascular endothelial growth factor (VEGF). Western bolt assay showed that Serine/threonine Kinase (Akt) signaling related proteins including Ataxia telangiectasia mutated kinase (ATM), Phosphatase and tensin homolog (PTEN), Akt, Mammalian target of rapamycin (mTOR), Ribosome S6 protein kinase (p70S6K) and e IF4E-binding protein 1(4E-BP1) were regulated, and Hypoxia inducible factor-1α (HIF-1α) protein expression was decreased by TSE1 in OVCAR-3 cells. Moreover, TSE1 treatment potently downregulated protein expression of the Notch ligands including Delta-like protein 4 (Dll4) and Jagged1, and reduced the protein level of the intracellular domain (NICD) of Notch1. Combination treatment of TSE1 with the Notch1 signaling inhibitor tert-butyl (2S)-2-[[(2S)-2-[[2-(3,5-difluorophenyl)acetyl]amino]propanoyl]amino]-2-phenylacetate (DAPT), or the Akt signaling inhibitor wortmannin, showed a stronger inhibition toward HIF-1α activation compared with single compound treatment. Taken together, TSE1 might be a potential candidate compound for improving platinum-resistant ovarian cancer treatment via Dll4/Jagged1-Notch1-Akt-HIF-1α axis.

Targeting the tumour microenvironment in platinum-resistant ovarian cancer

Ovarian cancer typically presents at an advanced stage, and although the majority of cases initially respond well to platinum-based therapies, chemoresistance almost always occurs leading to a poor long-term prognosis. While various cellular autonomous mechanisms contribute to intrinsic or acquired platinum resistance, the tumour microenvironment (TME) plays a central role in resistance to therapy and disease progression by providing cancer stem cell niches, promoting tumour cell metabolic reprogramming, reducing chemotherapy drug perfusion and promoting an immunosuppressive environment. As such, the TME is an attractive therapeutic target which has been the focus of intense research in recent years. This review provides an overview of the unique ovarian cancer TME and its role in disease progression and therapy resistance, highlighting some of the latest preclinical and clinical data on TME-targeted therapies. In particular, it focuses on strategies targeting cancer-associated fibroblasts, tumour-associated macrophages, cancer stem cells and cancer cell metabolic vulnerabilities.

Changes in the Tumor Immune Microenvironment during Disease Progression in Patients with Ovarian Cancer

Simple Summary

Immunotherapy has been a successful treatment for many cancers. However, no immunotherapy treatment has been approved for ovarian cancer due to low efficacy in this patient group. This study investigated the cellular and molecular changes from primary ovarian tumors, at the time of diagnosis, to recurrence, where the disease returns after surgery and chemotherapies. Here we examined the immune contexture to better understand subdued responses to immunotherapy and identify additional, potentially complimentary, therapeutic targets. Indications of the development of adaptive immune resistance during disease progression were observed, with increases in immune and stromal cell infiltration accompanied by the expression of immune suppressive markers. We observed high gene expression of the immune checkpoint genes LAG3 and HAVCR2 (TIM3) in most tumors and increased expression of the immune checkpoint genes TIGIT and CTLA4 in recurrent tumors, compared to the primaries. These markers may be potential candidates for immunotherapy targeting in ovarian cancer.

Abstract

Anti-PD1/PDL1 therapy has proven efficacious against many cancers but only reached modest objective response rates against recurrent ovarian cancer. A deeper understanding of the tumor microenvironment (TME) may reveal other immunosuppressive mechanisms that warrant investigation as immunotherapeutic targets for this challenging disease. Matched primary and recurrent tumors from patients with high-grade serous ovarian carcinoma (HGSC) were analyzed by multicolor immunohistochemistry/immunofluorescence for the presence of T cells, B cells, macrophages, and for the expression of immunosuppressive and HLA molecules. Cancer- and immune-related gene expression was assessed by NanoString analysis. Recurrent tumors showed increased infiltration by immune cells, displayed higher expression of PDL1, IDO, and HLA molecules, and contained more stromal tissue. NanoString analysis demonstrated increased expression of gene signatures related to chemokines and T cell functions in recurrent tumors. The ovarian tumors showed high gene expression of LAG3 and HAVCR2 (TIM3) and enhanced levels of TIGIT and CTLA4 in recurrent tumors compared to primary tumors. The majority of HGSC developed into a more inflamed phenotype during progression from primary to recurrent disease, including indications of adaptive immune resistance. This suggests that recurrent tumors may be particularly sensitive to inhibition of adaptive immune resistance mechanisms.

Secondary and tertiary ovarian cancer recurrence: what is the best management?

Ovarian cancer with complete clinical response recurs with a high rate. Recurrence is observed in almost 25% of cases with early-stage diseases and in more than 80% with more advance stages. Based on a platinum-free interval cut-off of 6 months, the first recurrence is usually classified in platinum-sensitive versus platinum-resistant, reflecting the biological characteristics underlying the clinical behavior. After this first recurrence, the patients are rarely cured, but second-line therapy can provide significant clinical responses, particularly in first platinum-sensitive recurrence. The approach to secondary and tertiary recurrence follows the same general principles applied in the first recurrence. Platinum-sensitivity based on the treatment-free interval defines the available chemotherapeutic regimens, whit less therapeutic options and a generally worse prognosis in platinum-resistant recurrent disease. Nevertheless, in this scenario, the introduction of new targeted therapies changed the prognosis of patients with both platinum-sensitive and platinum-resistant recurrence. The first introduced antiangiogenic therapy resulted able to improve prognosis in recurrent disease both as a single-agent and combined therapy, although the growing adoption in the first line therapy requires further investigation to prove their efficacy after repeated use. More recently, the approach to secondary, tertiary, and later recurrence has been changed by the introduction of PARP inhibitors, which resulted effective as maintenance monotherapy in both platinum-sensitive and platinum-resistant recurrence when the genetic background of the tumor allows their application with a significant improvement of oncological outcomes. Overall, although the growing body of promising therapeutic options to approach recurrent ovarian cancer, all the available evidence suggests that the best unique management of secondary and tertiary recurrence does not exist but should be personalized based on the disease characteristics, previous treatments, patient characteristics, and patient preference. On that basis, in this review, we report a general and complete overview of the approach at the secondary and tertiary ovarian cancer recurrence with the aim to provide a wide vision on the multiple available therapeutic options.

Signaling within the epithelial ovarian cancer tumor microenvironment: the challenge of tumor heterogeneity

Epithelial ovarian cancer (EOC) is a leading cause of cancer death in women. Standard of care treatment has remained platinum-containing cytotoxic chemotherapy for over three decades. Among the central challenges in treating ovarian CA are disease recurrence and the development of chemoresistance. Survival is uniformly poor for patients with chemoresistant recurrent disease and effective therapeutic options are limited. As such, delineating the mechanisms of chemoresistance and developing targeted therapies to prevent chemoresistance from occurring are of vital importance to improving survival for patients with EOC. Attempts to characterize mechanisms of chemoresistance have implicated numerous cellular pathways, but a rift remains between pre-clinical findings and translation to improving patient survival. More recently, the interplay among different cell types within the tumor microenvironment has become central to understanding how chemoresistance may develop and may be sustained. An improved understanding of how tumor cell-intrinsic and -extrinsic pathways converge during the development of chemoresistance may improve the likelihood of successful clinical translation. This review focuses on the roles of the EOC tumor microenvironment and tumor cell heterogeneity in the development of chemoresistance. We review recent studies into mechanisms of chemoresistance as they relate to tumor microenvironment and development of novel therapeutic approaches that exploit these mechanisms to prevent or reverse chemoresistance. This review attempts to cast these latest discoveries in a clinical context by summarizing trends in ongoing clinical trials for patients with EOC.

Bevacizumab or PARP-Inhibitors Maintenance Therapy for Platinum-Sensitive Recurrent Ovarian Cancer: A Network Meta-Analysis

Introduction: Targeted agents such as bevacizumab (BEV) or poly (ADP-ribose) polymerase inhibitors (PARPi) which have been added as concomitant or maintenance therapies have been shown to improve progression-free survival (PFS) in patients with platinum-sensitive recurrent ovarian cancer (PS rOC). In the absence of direct comparison, we performed a network meta-analysis considering BRCA genes status. Methods: We searched PubMed, EMBASE, and MEDLINE for trials involving patients with PS rOC treated with BEV or PARPi. Different comparisons were performed for patients included in the PARPi trials, according to BRCA genes status as follows: all comers (AC) population, BRCA 1/2 mutated (BRCAm), and BRCA wild type patients (BRCAwt). Results: In the overall population, PARPi prolonged PFS with respect to BEV (hazard ratio (HR) = 0.70, 95% CI 0.54–0.91). In the BRCA mutated carriers, the PFS improvement in favor of PARPi appeared to be higher (HR = 0.46, 95% CI 0.36–0.59) while in BRCAwt patients the superiority of PARPi over BEV failed to reach a statistically significance level (HR = 0.87, 95% CI 0.63–1.20); however, according to the SUCRA analysis, PARPi had the highest probability of being ranked as the most effective therapy (90% and 60%, for PARPi and BEV, respectively). Conclusions: PARPi performed better as compared with BEV in terms of PFS for the treatment of PS rOC, especially in BRCAm patients who had not previously received PARPi.

Survey on the current gynaecological approach of ovarian cancer patients: The utility of HIPEC

BACKGROUND

The aim of this survey was to acquire an overview of the current management of ovarian cancer with an emphasis on the utility of hyperthermic intraperitoneal chemotherapy (HIPEC).Methods: An email was sent to Oncologists prior to PSOGI International Symposium on Advanced Ovarian Cancer, Athens 11-13 April 2019. Doctors submitted responses on the relevant website. The self-report survey contained 17 questions.

RESULTS

In total, 467 Medical Oncologists, Surgical Oncologists or Gynaecologic Oncologists were participated and answered to this survey. The resectability of disease was evaluated by laparoscopy from 48.5% of the participants, while 51.5% answered that they stage their patients pre-surgically with the use of CT or MRI. The preferred first intervention in advanced ovarian cancer patients is the neoadjuvant chemotherapy followed by interval cytoreductive surgery (72%). Regarding the use of HIPEC, almost half of the participants answered that there is role of HIPEC use in ovarian cancer patients undergoing interval debulking surgery, while almost 70% answered positively about the utility of HIPEC use in ovarian cancer recurrence. As for the role of lymphadenectomy in advanced ovarian cancer patients, half of the responders answered negatively. Finally, only 25% of the participants responded that they always check the BRCA status of their ovarian cancer patients, despite the possible differentiation of treatment based on the molecular profiling (80%).

CONCLUSIONS

The results of this survey indicate the utility of HIPEC in treatment of ovarian cancer patients and the differences in the overall management of ovarian cancer patients in the current clinical practice.

Cyclic Peptides Acting as Allosteric Inhibitors of Human Thymidylate Synthase and Cancer Cell Growth

Thymidylate synthase (TS) is a prominent drug target for different cancer types. However, the prolonged use of its classical inhibitors, substrate analogs that bind at the active site, leads to TS overexpression and drug resistance in the clinic. In the effort to identify anti-TS drugs with new modes of action and able to overcome platinum drug resistance in ovarian cancer, octapeptides with a new allosteric inhibition mechanism were identified as cancer cell growth inhibitors that do not cause TS overexpression. To improve the biological properties, 10 cyclic peptides (cPs) were designed from the lead peptides and synthesized. The cPs were screened for the ability to inhibit recombinant human thymidylate synthase (hTS), and peptide 7 was found to act as an allosteric inhibitor more potent than its parent open-chain peptide [Pro³]LR. In cytotoxicity studies on three human ovarian cancer cell lines, IGROV-1, A2780, and A2780/CP, peptide 5 and two other cPs, including 7, showed IC₅₀ values comparable with those of the reference drug 5-fluorouracil, of the open-chain peptide [d-Gln⁴]LR, and of another seven prolyl derivatives of the lead peptide LR. These promising results indicate cP 7 as a possible lead compound to be chemically modified with the aim of improving both allosteric TS inhibitory activity and anticancer effectiveness.

Heat Shock Proteins and Ovarian Cancer: Important Roles and Therapeutic Opportunities

Ovarian cancer is a serious cause of death in gynecological oncology. Delayed diagnosis and poor survival rates associated with late stages of the disease are major obstacles against treatment efforts. Heat shock proteins (HSPs) are stress responsive molecules known to be crucial in many cancer types including ovarian cancer. Clusterin (CLU), a unique chaperone protein with analogous oncogenic criteria to HSPs, has also been proven to confer resistance to anti-cancer drugs. Indeed, these chaperone molecules have been implicated in diagnosis, prognosis, metastasis and aggressiveness of various cancers. However, relative to other cancers, there is limited body of knowledge about the molecular roles of these chaperones in ovarian cancer. In the current review, we shed light on the diverse roles of HSPs as well as related chaperone proteins like CLU in the pathogenesis of ovarian cancer and elucidate their potential as effective drug targets.

Recent advances on anti-angiogenesis receptor tyrosine kinase inhibitors in cancer therapy

Angiogenesis has always been the topic of major scientific interest in the field of malignant tumors. Nowadays, targeting angiogenesis has achieved success in various carcinomas by several mechanisms, including the use of anti-angiogenic small molecule receptor tyrosine kinase inhibitors (TKIs). The development of TKIs targeting pro-angiogenic receptors, mainly vascular endothelial growth factor receptor (VEGFR) family, have significantly improved the outcome of certain types of cancers, like renal cell carcinoma, hepatocellular carcinoma, and colorectal carcinoma. However, the general response rate is not very satisfactory. The particular toxicity profile and resistance to anti-angiogenic targeted agents are unavoidable, and no specific marker is available to screen responsive patients to TKIs for precision therapy. To date, about 11 anti-angiogenic TKIs with different binding capacities to angiogenic receptor tyrosine kinase have been approved for the treatment of patients with advanced cancers. This review presents all approved anti-angiogenic small molecule receptor TKIs so far with an emphasis on their indications and clinical efficacy. We also discuss the combination between TKIs and immune checkpoint blockade inhibitors based on the most recent exciting outcome in immunotherapy.