Combined Strategies with Poly (ADP-Ribose) Polymerase (PARP) Inhibitors for the Treatment of Ovarian Cancer: A Literature Review

Recent advancements of antiangiogenic combination therapies in ovarian cancer

Ovarian cancer is a deadly malignancy with a growing therapeutic armamentarium, though achieving sustained benefit in the clinic remains largely elusive. Through biomarker and genetic analysis, several pathways of resistance and sensitivity to commonly used therapeutics have been identified, expanding the potential of identifying unique drug combinations and indicating new directions for improving clinical outcomes. Here, we review the mechanisms of angiogenic response and antiangiogenic therapy in ovarian cancer, as well as the interactions it exhibits with the immune and DNA damage response pathways. We discuss results from clinical trials examining the combinations of antiangiogenics, PARP inhibitors, and immune checkpoint inhibitors are also discussed, as well as several ongoing trials.

PARP1: A Potential Molecular Marker to Identify Cancer During Colposcopy Procedures

Despite efforts in prevention, cervical cancer still presents with a high worldwide incidence and remains a great problem in public health, especially in low-income countries. Screening programs, such as colposcopy with Papanicolaou testing, have greatly improved mortality rates. However, the agents currently used to delineate those lesions (topical application of acetic acid or Lugol iodine) lack specificity and sometimes can lead to unnecessary biopsies or even cervical excisions. A tool to enable in vivo histology to quickly and quantitatively distinguish between tumor, dysplastic tissue, and healthy tissue would be of great clinical interest. Methods: Here, we describe the use of PARPi-FL, a fluorescent inhibitor of poly[adenosine diphosphate-ribose]polymerase 1 (PARP1), which is a nuclear enzyme that is overexpressed in cancer when compared with the normal surrounding tissues. We exploit its use as an optical imaging agent to specifically target PARP1 expression, which was demonstrated to be higher in cervical cancer than the normal surrounding tissue. Results: After topical application of PARPi-FL on freshly excised cone biopsy samples, the nuclei of tumor cells emitted a specific fluorescent signal that could be visualized using a handheld fluorescence confocal microscope. Conclusion: This approach has the potential to improve in vivo identification of tumor cells during colposcopy examination, allowing a rapid, noninvasive, and accurate histopathologic assessment.

PARP Power: A Structural Perspective on PARP1, PARP2, and PARP3 in DNA Damage Repair and Nucleosome Remodelling

Poly (ADP-ribose) polymerases (PARP) 1-3 are well-known multi-domain enzymes, catalysing the covalent modification of proteins, DNA, and themselves. They attach mono- or poly-ADP-ribose to targets using NAD⁺ as a substrate. Poly-ADP-ribosylation (PARylation) is central to the important functions of PARP enzymes in the DNA damage response and nucleosome remodelling. Activation of PARP happens through DNA binding via zinc fingers and/or the WGR domain. Modulation of their activity using PARP inhibitors occupying the NAD⁺ binding site has proven successful in cancer therapies. For decades, studies set out to elucidate their full-length molecular structure and activation mechanism. In the last five years, significant advances have progressed the structural and functional understanding of PARP1-3, such as understanding allosteric activation via inter-domain contacts, how PARP senses damaged DNA in the crowded nucleus, and the complementary role of histone PARylation factor 1 in modulating the active site of PARP. Here, we review these advances together with the versatility of PARP domains involved in DNA binding, the targets and shape of PARylation and the role of PARPs in nucleosome remodelling.

The Ubiquitin Ligase TRIP12 Limits PARP1 Trapping and Constrains PARP Inhibitor Efficiency

PARP inhibitors (PARPi) cause synthetic lethality in BRCA-deficient tumors. Whether specific vulnerabilities to PARPi exist beyond BRCA mutations and related defects in homology-directed repair (HDR) is not well understood. Here, we identify the ubiquitin E3 ligase TRIP12 as negative regulator of PARPi sensitivity. We show that TRIP12 controls steady-state PARP1 levels and limits PARPi-induced cytotoxic PARP1 trapping. Upon loss of TRIP12, elevated PARPi-induced PARP1 trapping causes increased DNA replication stress, DNA damage, cell cycle arrest, and cell death. Mechanistically, we demonstrate that TRIP12 binds PARP1 via a central PAR-binding WWE domain and, using its carboxy-terminal HECT domain, catalyzes polyubiquitylation of PARP1, triggering proteasomal degradation and preventing supra-physiological PARP1 accumulation. Further, in cohorts of breast and ovarian cancer patients, PARP1 abundance is negatively correlated with TRIP12 expression. We thus propose TRIP12 as regulator of PARP1 stability and PARPi-induced PARP trapping, with potential implications for PARPi sensitivity and resistance.

Analysis of the association between KIN17 expression and the clinical features/prognosis of epithelial ovarian cancer, and the effects of KIN17 in SKOV3 cells

DNA double-strand breaks (DSBs) are an important mechanism of chemotherapy in epithelial ovarian cancer (EOC). Kin17 DNA and RNA binding protein (KIN17) serves a crucial role in DSB repair. In the present study, the association between KIN17 and EOC, and the effects of KIN17 on EOC cells in vitro were evaluated. A bioinformatics method was used to determine the mRNA expression levels of KIN17 in EOC and its association with EOC prognosis including overall survival (OS) and progression free survival (PFS) time. Western blotting and immunohistochemical staining were used to evaluate the expression levels of KIN17 in EOC samples. Kaplan-Meier and Cox regression analyses were utilized to analyze risk factors for the OS of patients with EOC. A Cell Counting Kit-8 assay was performed to explore the roles of KIN17 in SKOV3 cells. Both the transcription and expression of KIN17 were upregulated in EOC tissues. Furthermore, the OS of patients with EOC with high mRNA expression levels of KIN17 was shorter than that of patients with EOC with low expression levels. High KIN17 expression was an independent risk factor for EOC prognosis. Furthermore, KIN17 knockdown inhibited the proliferation of SKOV3 cells, enhanced the sensitivity of the cells to cisplatin and inhibited the migration ability of the cells. These results suggested that KIN17 may act as an ideal candidate for therapy and as a prognostic biomarker of EOC, although the underlying mechanisms require further exploration.

Poly (ADP-ribose) polymerase (PARP) as target for the treatment of epithelial ovarian cancer: what to know

INTRODUCTION

Poly (ADP-ribose) polymerase (PARP) inhibitors are being developed in maintenance and recurrence treatment settings of epithelial ovarian cancers (EOCs) with BRCA 1-2 gene mutation. PARP inhibitors are the first example of drugs targeting the loss of a gene suppressor: they block base-excision repair in the cancer cells, which have lost homologous recombination due to BRCA-mutation, resulting in loss of DNA repair and cell death, also known as synthetic lethality.

AREAS COVERED

This article provides an overview of PARP inhibitors in OC treatment and also an extensive section on the combined strategies of PARP inhibitors, including approved as well as currently investigated drugs. It also offers a section on the use of predictive biomarkers for PARP inhibitors treatment. Ongoing trials, including novel combinations, are discussed.

EXPERT OPINION

In recent years, there is increasing evidence that PARP inhibitor therapy can have life-long percussion in the treatment of EOC, even if some questions have to be solved yet, such as its use in combination therapy, the possibility to retreat with a PARP inhibitor, and finally how to overcome a resistance mechanism to this therapy. In this way, PARP inhibitors can obtain an important role in making a personalized therapeutic program in the case of first-line, neoadjuvant, platinum-sensitive, and resistant high-grade serous OC treatment.

Poly(ADP-ribose) polymerase inhibitors in combination with anti-angiogenic agents for the treatment of advanced ovarian cancer

Homologous recombination deficiency and VEGF expression are key pathways in high-grade ovarian cancer. Recently, three randomized practice changing trials were published: the PAOLA-1, PRIMA and VELIA trials. The use of PARP inhibitors (PARPi) following chemotherapy has become standard of care in first line. Combination of PARPi with anti-angiogenic agents has demonstrated synergistic activity in preclinical study. This review summarizes the body of evidence supporting the efficacy and safety of the combination of PARPi and anti-angiogenic drugs in first-line homologous recombination deficiency high-grade ovarian cancer leading to US FDA and EMA approvals. This double maintenance is supported by: a large benefit with bevacizumab + olaparib compared with olaparib alone, a rationale for additive effect, and a good safety and cost-effective profile.

Germline and tumor BRCA1/2 mutations in Chinese high grade serous ovarian cancer patients

Background

Studies on the prevalence of BRCA1/2 mutations in ovarian cancer mainly focused on germline single-nucleotide variant (SNV)/insertion/deletion (indel). The status of large genomic rearrangement (LRG) and somatic mutation were poorly investigated.

Methods

Paired blood and tumor DNA from an unselected cohort of 115 Chinese high grade serous ovarian cancer (HGSOC) patients were collected and analyzed for BRCA1/2 SNV and indel by NGS. BRCA1/2 LRG was detected by MLPA. Clinicopathological characteristics including age at diagnosis, FIGO stage, family history and follow-up data were collected for further analysis.

Results

A total of 115 HGSOC patients were screened. Among them, 30 (26.1%) had germline BRCA1/2 mutations, including 19 (16.5%) SNV/indels, 5 (4.3%) LGRs in BRCA1, and 6 (5.2%) SNV/indels in BRCA2. Ten (8.7%) had somatic BRCA1/2 mutations, including 5 (4.3%) in BRCA1 and 5 (4.3%) in BRCA2. The entire tumor BRCA1/2 mutation frequency was 34.8%. No patients were found with two or more deleterious BRCA1/2 mutations. The proportion of germline (66.7%) and tumor (75%) mutation carriers was significantly increased for patients with family history when compared with those without (P<0.05). Patients with germline BRCA1/2 mutation appeared to be younger than non-carriers (mean age, 50.9 vs. 54.4 years, P=0.004) and somatic mutation carriers (mean age, 50.9 vs. 58.7 years, P=0.009). No significant association was found between BRCA1/2 status and clinicopathological characteristics including stage and family history of other cancer than breast and ovarian cancer. In univariate and Cox regression analysis, patients with tumor BRCA1/2 mutations had significant improvements than non-carriers in overall survival in the first two years after surgery (P<0.05). No significant impacts were found between various mutation status in PFS.

Conclusions

There is a high germline and tumor BRCA1/2 mutation incidences in Chinese HGSOC patients. Germline mutations were associated with family history and age at diagnosis, whereas somatic mutations were not. In our study, tumor BRCA1/2 mutations showed a time-depended improved survival outcome. A larger cohort should be examined to clarify the relation between BRCA1/2 mutation and survival outcomes.

MiR-200c-3p Contrasts PD-L1 Induction by Combinatorial Therapies and Slows Proliferation of Epithelial Ovarian Cancer through Downregulation of β-Catenin and c-Myc

Conventional/targeted chemotherapies and ionizing radiation (IR) are being used both as monotherapies and in combination for the treatment of epithelial ovarian cancer (EOC). Several studies show that these therapies might favor oncogenic signaling and impede anti-tumor responses. MiR-200c is considered a master regulator of EOC-related oncogenes. In this study, we sought to investigate if chemotherapy and IR could influence the expression of miR-200c-3p and its target genes, like the immune checkpoint PD-L1 and other oncogenes in a cohort of EOC patients’ biopsies. Indeed, PD-L1 expression was induced, while miR-200c-3p was significantly reduced in these biopsies post-therapy. The effect of miR-200c-3p target genes was assessed in miR-200c transfected SKOV3 cells untreated and treated with olaparib and IR alone. Under all experimental conditions, miR-200c-3p concomitantly reduced PD-L1, c-Myc and β-catenin expression and sensitized ovarian cancer cells to olaparib and irradiation. In silico analyses further confirmed the anti-correlation between miR-200c-3p with c-Myc and β-catenin in 46 OC cell lines and showed that a higher miR-200c-3p expression associates with a less tumorigenic microenvironment. These findings provide new insights into how miR-200c-3p could be used to hold in check the adverse effects of conventional chemotherapy, targeted therapy and radiation therapy, and offer a novel therapeutic strategy for EOC.

Efficient iron utilization compensates for loss of extracellular matrix of ovarian cancer spheroids

Metastasis is the major cause of death in women with advanced ovarian cancer. Epithelial ovarian cancer cells can dissociate directly from extracellular matrix (ECM) and form spheroids to spread through the peritoneal cavity. Loss of ECM hinders the survival of ECM-detached epithelial cells. It is still largely unknown how ovarian cancer spheroids maintain their viability after loss of ECM. We find that spheroids derived either from ovarian cancer ascites or cell lines are iron-replete. In accordance with iron-replete condition, proteins involved in iron uptake, transport and storage including divalent metal ion transporter 1 (DMT1), transferrin receptor 1 (TFR1), ferritin, poly(rC)-binding proteins 1 and 2 (PCBP1 and 2) and nuclear factor E2-related factor 2 (NRF2) all increase in ovarian cancer spheroids. Genes linking iron homeostasis and lipid metabolism including stearoyl coenzyme A desaturase 1 (SCD1) are up-regulated in ovarian cancer spheroids. The product of SCD1 oleic acid can restore the viability of ovarian cancer spheroids inhibited by deprivation of iron. Extracellular signal-regulated kinase (ERK) activation contributes to autophagy activation in ovarian cancer spheroids. Impairment of autophagy by U0126 or Olaparib results in lysosomal iron accumulation and decrease of the cytosolic labile iron pool, leading to reduction of SCD1, lipid level and cell viability. Combination of U0126 and Olaparib has synergistic cytotoxicity toward ovarian cancer spheroids. Our findings reveal that ovarian cancer spheroids develop efficient iron utilization system to survive. Targeting iron utilization in ovarian cancer spheroids may have the potential to become new treatment strategies for ovarian cancer metastasis.

Current practices on genetic testing in ovarian cancer

Epithelial ovarian cancer (EOC) is probably the tumor type with the highest percentage of hereditary cases observed, irrespectively of selection criteria. A fourth to a fifth of unselected epithelial EOC patients carry pathogenic variants (PVs) in a number of genes, the majority of which encode for proteins involved in DNA repair pathways. BRCA1 and BRCA2 predisposing PVs were the first to be associated to ovarian cancer, with the advent in DNA sequencing technologies leading to the discovery and association of additional genes which compromise the homologous recombination (HR) pathway. In addition, PVs genes involved in mismatch repair (MMR) pathway, account for 10–15% of hereditary EOC. The identification of women with HR deficient ovarian cancers has significant clinical implications concerning chemotherapy regimen planning and development and use of targeted therapies as well. More specifically, in patients with BRCA1/2 PVs or HR deficiency maintenance treatment with poly(ADP-ribose) polymerase (PARP) inhibitors, either in the first line setting or in recurrent disease, improves the progression-free survival. But also patients with HR proficient tumors show a benefit. Therefore, genetic testing in ovarian cancer has a prognostic and predictive value. In this review, we discuss which ovarian cancer patients should be referred for genetic counseling and how to perform genetic testing. We also discuss the timing of genetic testing and its clinical relevance to BRCA status.

PD-1/PD-L1 checkpoint inhibitors in combination with olaparib display antitumor activity in ovarian cancer patient-derived three-dimensional spheroid cultures

Immune checkpoint inhibitors (ICIs) that target programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) have shown modest activity as monotherapies for the treatment of ovarian cancer (OC). The rationale for using these therapies in combination with poly (ADP-ribose) polymerase inhibitors (PARP-Is) has been described, and their in vivo application will benefit from ex vivo platforms that aid in the prediction of patient response or resistance to therapy. This study examined the effectiveness of detecting patient-specific immune-related activity in OC using three-dimensional (3D) spheroids. Immune-related cell composition and PD-1/PD-L1 expression status were evaluated using cells dissociated from fresh OC tissue from two patients prior to and following 3D culture. The patient sample with the greatest increase in the proportion of PD-L1 + cells also possessed more activated cytotoxic T cells and mature DCs compared to the other patient sample. Upon cytokine stimulation, patient samples demonstrated increases in cytotoxic T cell activation and DC major histocompatibility complex (MHC) class-II expression. Pembrolizumab increased cytokine secretion, enhanced olaparib cytotoxicity, and reduced spheroid viability in a T cell-dependent manner. Furthermore, durvalumab and olaparib combination treatment increased cell death in a synergistic manner. This work demonstrates that immune cell activity and functional modulation can be accurately detected using our ex vivo 3D spheroid platform, and it presents evidence for their utility to demonstrate sensitivity to ICIs alone or in combination with PARP-Is in a preclinical setting.

[18F]PARPi Imaging Is Not Affected by HPV Status In Vitro

Background

Human papillomavirus- (HPV-) associated oropharyngeal squamous cell carcinomas (OPSCCs) are clinically and pathologically distinct from HPV-negative tumors. Here, we explore whether HPV affects functional biomarkers, including γH2AX, RAD51, and PARP1. Moreover, the role of [18F]PARPi as a broadly applicable imaging tool for head and neck carcinomas is investigated.

Methods

HPV-positive and HPV-negative cell lines were used to evaluate the γH2AX, RAD51, and PARP1 expression with immunoblotting and immunofluorescence. Effects of external beam ionizing radiation were investigated in vitro, and survival was investigated via colony-formation assay. [18F]PARPi uptake experiments were performed on HPV-negative and HPV-positive cell lines to quantify PARP1 expression. PARP1 IHC and γH2AX foci were quantified using patient-derived oropharyngeal tumor specimens.

Results

Differences in DNA repair were detected, showing higher RAD51 and γH2AX expression in HPV-positive cell lines. Clonogenic assays confirm HPV-positive cell lines to be significantly more radiosensitive. PARP1 expression levels were similar, irrespective of HPV status. Consequently, [18F]PARPi uptake assays demonstrated that this tracer is internalized in cell lines independently from their HPV status.

Conclusion

The HPV status, often used clinically to stratify patients, did not affect PARP1 levels, suggesting that PARP imaging can be performed in both HPV-positive and HPV-negative patients. This study confirms that the PET imaging agent [18F]PARPi could serve as a general clinical tool for oropharyngeal cancer patients.

Haematologic toxicities with PARP inhibitors in cancer patients: an up-to-date meta-analysis of 29 randomized controlled trials

WHAT IS KNOWN AND OBJECTIVE

Poly ADP-ribose polymerase (PARP) inhibitors have emerged as one of the most exciting new treatments for patients with certain types of cancer. Haematologic toxicities are common adverse events (AEs) for all PARP inhibitors. We conducted a meta-analysis to fully investigate the haematologic toxicities of PARP inhibitors in cancer patients.

STUDY DESIGN

PubMed/Medline and Embase were searched for articles published till September 2020. The relevant randomized controlled trials (RCTs) in cancer patients treated with PARP inhibitors were retrieved, and the systematic evaluation was performed.

RESULTS

Twenty-nine RCTs and 9247 patients were included. The current meta-analysis suggests that the use of PARP inhibitors significantly increases the risk of all-grade anaemia (RR, 2.32; 95% CI, 1.78-3.01; p < 0.00001), neutropenia (RR, 1.69; 95% CI, 1.38-2.07; p < 0.00001) and thrombocytopenia (RR, 2.54; 95% CI, 1.87-3.45; p < 0.00001). The use of these agents also significantly increased the risk of high-grade anaemia (RR, 3.06; 95% CI, 2.11-4.43; p < 0.00001), neutropenia (RR, 1.66; 95% CI, 1.33-2.07; p < 0.00001) and thrombocytopenia (RR, 2.76; 95% CI, 1.83-4.16; p < 0.00001). Anaemia was the most common haematologic toxicity, and all the five included PARP inhibitors were associated with a significant increased risk of anaemia. Combination treatment may reduce the risk of anaemia and thrombocytopenia compared to those receiving PARP inhibitor monotherapy.

WHAT IS NEW AND CONCLUSION

The available data suggested that the use of PARP inhibitors was associated with a significantly increased risk of haematologic toxicities.

Frontiers in combining immune checkpoint inhibitors for advanced urothelial cancer management

PURPOSE OF REVIEW

This review provides an overview of currently ongoing clinical trials evaluating the combination of immune checkpoint inhibitors (CPI) with other therapies in locally advanced or metastatic urothelial cancer and the rationale for this combination approach. We discuss the preliminary results from early data presented at recent meetings regarding the efficacy and safety of novel combination therapies including a CPI for metastatic urothelial cancer.

RECENT FINDINGS

CPI emerged as novel first-line or second-line treatment options in advanced and metastatic urothelial cancer (mUC). Although the response rates and their sustainability are promising, it is far from a home run. Combination therapies have already shown improved efficacy in several other tumor entities.

SUMMARY

Numerous clinical trials currently investigate combinations of CPI with other CPI, previously established systemic chemotherapy, targeted therapies, vaccines, or accompanied with radiotherapy. Preliminary data shows promising results. These results suggest that targeting pathways of immune response combined with established or novel oncological therapies may lead to a synergistic antitumor effect.

Poly (ADP-Ribose) Polymerase Inhibitors: Talazoparib in Ovarian Cancer and Beyond

Genetic complexity and DNA damage repair defects are common in different cancer types and can induce tumor-specific vulnerabilities. Poly(ADP-ribose) polymerase (PARP) inhibitors exploit defects in the DNA repair pathway through synthetic lethality and have emerged as promising anticancer therapies, especially in tumors harboring deleterious germline or somatic breast cancer susceptibility gene (BRCA) mutations. However, the utility of PARP inhibitors could be expanded beyond germline BRCA1/2 mutated cancers by causing DNA damage with cytotoxic agents in the presence of a DNA repair inhibitor. US Food and Drug Administration (FDA)-approved PARP inhibitors include olaparib, rucaparib, and niraparib, while veliparib is in the late stage of clinical development. Talazoparib inhibits PARP catalytic activity, trapping PARP1/2 on damaged DNA, and it has been approved by the US FDA for the treatment of metastatic germline BRCA1/2 mutated breast cancers in October 2018. The talazoparib side effect profile more closely resembles traditional chemotherapeutics rather than other clinically approved PARP inhibitors. In this review, we discuss the scientific evidence that has emerged from both experimental and clinical studies in the development of talazoparib. Future directions will include optimizing combination therapy with chemotherapy, immunotherapies and targeted therapies, and in developing and validating biomarkers for patient selection and stratification, particularly in malignancies with ‘BRCAness’.

Pharmacological Inhibition of BAD Ser99 Phosphorylation Enhances the Efficacy of Cisplatin in Ovarian Cancer by Inhibition of Cancer Stem Cell-like Behavior

Platinum-based chemotherapy has been the standard treatment for ovarian cancer patients for approximately four decades. However, the prognosis of patients with advanced ovarian carcinoma remains dismal, mainly attributed to both dose-limiting toxicities of cisplatin and the high rate of chemo-resistant disease recurrence. Herein, both patient-derived and experimentally generated cisplatin-sensitive and -resistant ovarian cancer cell line models were used to delineate BADSer99 phosphorylation as an actionable target in ovarian cancer. BADSer99 phosphorylation was negatively associated with cisplatin sensitivity in ovarian cancer, and the inhibition of BADSer99 phosphorylation by point mutation induced apoptosis and reduced cisplatin IC₅₀. In addition, BAD phosphorylation was also shown to be associated with cancer stem cell-like properties. Henceforth, a novel small molecule which inhibits BAD phosphorylation specifically at Ser99 (NPB) was utilized. NPB promoted apoptosis and reduced 3D growth of bulk cancer cells and inhibited cancer stem cell-like properties in both cisplatin-sensitive and -resistant ovarian cancer cells. The combination of cisplatin with NPB exhibited synergistic effects in vitro. NPB in combination with cisplatin also achieved an improved outcome compared to either monotreatment in vivo, including suppression of the cancer stem cell population, an effect not observed with cisplatin treatment. Furthermore, NPB exhibited strong synergistic effects with the AKT inhibitor AZD5363, and significantly reduced its IC₅₀ in cells resistant to cisplatin treatment. These findings identify BADSer99 phosphorylation as an actionable and pharmacologically relevant target to improve outcomes of cisplatin treated ovarian cancer.

PARP1 and PRC2 double deficiency promotes BRCA-proficient breast cancer growth by modification of the tumor microenvironment

Poly (ADP-ribose) polymerase 1 (PARP1) and polycomb-repressive complex 2 (PRC2) are each known for their individual roles in cancer, but their cooperative roles have only been studied in the DNA damage repair process in the context of BRCA-mutant cancers. Here, we show that simultaneous inhibition of PARP1 and PRC2 in the MDA-MB-231 BRCA-proficient triple-negative breast cancer (TNBC) cell line leads to a synthetic viability independent of the mechanisms of DNA damage repair. Specifically, we find that either genetic depletion or pharmacological inhibition of both PARP1 and PRC2 can accelerate tumor growth rate. We attribute this to modifications in the tumor microenvironment (TME) that are induced by double-depleted breast cancer cells, such as promoting intratumoral angiogenesis and increasing the proportion of tumor-promoting type 2 (M2) macrophages. These changes subsequently inhibit cell death and promote proliferation. Mechanistically, we find that PARP1 and PRC2 double depletion induces not only a basal activation of the NF-κB pathway but also a maximal activation of NF-κB within the TME in response to external stimuli such as hypoxia and the presence of macrophages. In summary, our study reveals an unprecedented synthetic viable interaction between PARP1 and PRC2 in BRCA-proficient TNBC and identifies NF-κB as the downstream mediator. DATABASE: RNA-seq data are available in the GEO databases under the accession GSE142769.

Upfront debulking surgery for high-grade serous ovarian carcinoma: current evidence

High-grade serous ovarian carcinoma (HGSOC) is a leading cause of mortality among women worldwide. Currently, there is no clear consensus over the regime these patients should receive. The main two options are upfront debulking surgery with adjuvant chemotherapy or neoadjuvant chemotherapy followed by interval debulking surgery (IDS). The former approach is proposed to be accompanied by lower chemoresistance rates but could lead to severe surgical comorbidities and lower quality of life (QoL). Optimizing patient’s selection for upfront debulking surgery might offer higher progression-free and overall survival rates. Further studies need to be conducted in order to elucidate the predictive factors, which are favorable for patients undergoing upfront debulking surgery in cases of high-grade serous ovarian cancer.

Extreme complications related to bevacizumab use in the treatment of ovarian cancer: a case series from a III level referral centre and review of the literature

In patients undergoing debulking surgery for ovarian cancer (OC), bevacizumab-combined chemotherapy has been reported to be associated with an increased incidence of adverse events (AEs). Reports in the literature have noted the overall morbidity of bevacizumab to be between 3.7% and 9%. The aim of this study is to report uncommon and unusual manifestations of morbidity in surgical cases performed at our third level referral centers for gynecologic oncology. Additionally, we review the rare and severe bevacizumab-related complications that have been described in the literature. We defined as "extreme", the particularly rare and/or severe complications up to determining a life-threatening condition or death, which are related to the use of bevacizumab. A case-series of extreme complications registered at our institutions were reported. In addition, a literature search of the PubMed, MEDLINE and EMBASE electronic databases was performed for this review. The studies collected included: 8 randomized controlled trials (RCT) and 5 prospective observational, 1 prospective phase-IV, 10 prospective phase-II, 2 prospective phase-I, and 20 retrospective studies, as well as 9 case reports. Bevacizumab was administered as primary treatment in adjuvant and neo-adjuvant setting in 16 and 5 studies respectively, as treatment for recurrence in 36 trials, and for secondary cytoreductive surgery (SCS) in 3 studies. The overall population administered with bevacizumab numbered 7,096 women. Extreme complications were observed in 591 patients, with a morbidity rate of the 8.3%. Overall, central nervous system (CNS), cardiovascular, gastrointestinal (GI) and primary infectious complications were seen in 22 patients (0.3%), 261 patients (3.7%), 159 patients (2.2%), and 8 patients (0.13%), respectively. Hemorrhagic and wound complications occurred in 18 women (0.25%), and 112 women (1.6%), respectively. Extreme complications related to the use of bevacizumab are rare, and often go unrecognized. The recognition and immediate management of such rare and life-threatening complications in patients treated at third level referral centers could significantly improve patient survival.

Narrative review on serous primary peritoneal carcinoma of unknown primary site: four questions to be answered

Serous peritoneal papillary carcinoma (SPPC) represents a particular cancer of unknown primary (CUP) entity that arises in the peritoneal surface lining the abdomen and pelvis without a discriminative primary tumor site. In this review, we discuss the validity of SPPC as a distinct entity. Clinically, patients with SPPC are older, have higher parity and later menarche, are more often obese and probably have poorer survival compared to those with primary ovarian cancer. Pathologically, SPPC is more anaplastic and multifocal, unlike primary ovarian cancer which is commonly unifocal. Biologically, it presents a higher expression of proliferative signals and similar cell cycle and DNA repair protein expression. These differences hint towards SPPC and primary ovarian cancer being as a spectrum of disease. Patients with SPPC are traditionally managed similarly to stage III–IV ovarian cancer. The recommended approach integrates aggressive cytoreductive surgery, hyperthermic intraperitoneal chemotherapy, and systemic chemotherapy to remove the macroscopic tumor, eradicate the microscopic residual disease, and control the microscopic metastasis. However, the available evidence lacks proper randomized or prospective studies on SPPC and is limited to retrospective series. The diligent identification of SPPC is warranted to design specific clinical trials that eventually evaluate the impact of the new therapeutics on this distinct entity.

Neoadjuvant treatment for newly diagnosed advanced ovarian cancer: where do we stand and where are we going?

Newly diagnosed high grade serous epithelial ovarian cancer (EOC) patients are treated with radical surgery followed by adjuvant platinum and taxane combination chemotherapy. In EOC patients where upfront surgery is contraindicated for medical reasons (e.g., comorbidities or poor performance status), or where complete cytoreduction cannot be achieved, neoadjuvant chemotherapy (NACT) prior to interval debulking surgery (IDS), and adjuvant chemotherapy is an alternative therapeutic option. There is currently a lack of consensus about who are the best candidates to receive NACT, and some authors have even suggested that this approach could be harmful in a subset of patients via promotion of early chemoresistance. Standard and novel imaging techniques together with a better molecular characterization of the disease have the potential to improve selection of patients, but ultimately well designed randomised clinical trials are needed to guide treatment decisions in this setting. The advent of new and effective treatment options (antiangiogenics and PARP inhibitors), now approved for use in the first line and relapse settings has opened the way to clinical trials aiming to investigate these agents as substitute or in addition to chemotherapy in the neoadjuvant setting in molecularly selected EOC patients. Here, we will review the evidence supporting the use of NACT in newly diagnosed EOCs, data highlighting the importance of its use in selected patients, new imaging methodologies and biomarkers that can guide patient selection.

Current and future immunotherapy approaches in ovarian cancer

Ovarian cancer (OC) is the major cause of gynecologic cancer deaths and relapse is common despite advances in surgery and systemic chemotherapy. Therefore, novel treatments are required to improve long-term outcomes of the disease. Efficacy of immunotherapy was demonstrated in many tumors and it has been since incorporated into clinical practice for them. Although early data form preclinical studies imply that OC has an immunogenic microenvironment, immune checkpoint inhibitors (ICIs) did not produce favorable results in clinical trials to date. This review will highlight data from clinical studies regarding immunotherapy in OC and its combination with other agents as well as immunologic prospects which could strengthen the therapeutic armament against the disease in the future.

Development of new poly(ADP-ribose) polymerase (PARP) inhibitors in ovarian cancer: Quo Vadis?

Epithelial ovarian cancer (EOC) is the fifth leading cause of cancer mortality among women, potentially due to ineffectiveness of screening tests for early detection. Patients typically present with advanced disease at diagnosis, whereas, up to 80% relapse and the estimated median progression-free survival (PFS) is approximately 12–18 months. Increased knowledge on the molecular biology of EOC resulted in the development of several targeted therapies, including poly(ADP-ribose) polymerase (PARP) inhibitors. These agents have changed the therapeutic approach of the EOC and exploit homologous recombination (HR) deficiency through synthetic lethality, especially in breast cancer genes 1 and 2 (BRCA1/2) mutation carriers. Furthermore, BRCA wild-type patients with other defects in the HR repair pathway, or those with platinum-resistant tumors may obtain benefit from this treatment. While PARP inhibitors as a class display many similarities, several differences in structure can translate into differences in tolerability and antitumor activity. Currently, olaparib, rucaparib, and niraparib have been approved by Food and Drug Administration (FDA) and/or European Medicines Agency (EMA) for the treatment of EOC, while veliparib is in the late stage of clinical development. Finally, since October 2018 talazoparib is FDA and EMA approved for BRCA carriers with metastatic breast cancers. In this article, we explore the mechanisms of DNA repair, synthetic lethality, efficiency of PARP inhibition, and provide an overview of early and ongoing clinical investigations of the novel PARP inhibitors veliparib and talazoparib.

New Perspectives for Resistance to PARP Inhibitors in Triple-Negative Breast Cancer

Poly (ADP-ribose) polymerase (PARP) inhibitors are a therapeutic milestone exerting a synthetic lethal effect in the treatment of cancer involving BRCA1/2 mutation. Theoretically, PARP inhibitors (PARPi) eliminate tumor cells by disrupting DNA damage repair through either PARylation or the homologous recombination (HR) pathway. However, resistance to PARPi greatly hinders therapeutic effectiveness in triple-negative breast cancer (TNBC). Owing to the high heterogeneity and few genetic targets in TNBC, there has been limited therapeutic progress in the past decades. In view of this, there is a need to circumvent resistance to PARPi and develop potential treatment strategies for TNBC. We present, herein, a review of the scientific progress and explore the mechanisms underlying PARPi resistance in TNBC. The complicated mechanisms of PARPi resistance, including drug exporter formation, loss of poly (ADP-ribose) glycohydrolase (PARG), HR reactivation, and restoration of replication fork stability, are discussed in detail in this review. Additionally, we also discuss new combination therapies with PARPi that can improve the clinical response in TNBC. The new perspectives for PARPi bring novel challenges and opportunities to overcome PARPi resistance in breast cancer.

Combining PARP Inhibition with Platinum, Ruthenium or Gold Complexes for Cancer Therapy

Platinum drugs are heavily used first-line chemotherapeutic agents for many solid tumours and have stimulated substantial interest in the biological activity of DNA-binding metal complexes. These complexes generate DNA lesions which trigger the activation of DNA damage response (DDR) pathways that are essential to maintain genomic integrity. Cancer cells exploit this intrinsic DNA repair network to counteract many types of chemotherapies. Now, advances in the molecular biology of cancer has paved the way for the combination of DDR inhibitors such as poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) and agents that induce high levels of DNA replication stress or single-strand break damage for synergistic cancer cell killing. In this review, we summarise early-stage, preclinical and clinical findings exploring platinum and emerging ruthenium anti-cancer complexes alongside PARPi in combination therapy for cancer and also describe emerging work on the ability of ruthenium and gold complexes to directly inhibit PARP activity.

Gastrointestinal events with PARP inhibitors in cancer patients: A meta-analysis of phase II/III randomized controlled trials

WHAT IS KNOWN AND OBJECTIVE

PARP inhibitors are currently one of the most promising PARP targeted drugs for patients with certain types of cancer. Gastrointestinal (GI) events are common adverse events for all PARP inhibitors. We conducted this meta-analysis of randomized controlled trials (RCTs) to fully investigate the incidence and the relative risk of GI events in cancer patients receiving PARP inhibitors.

STUDY DESIGN

Randomized controlled trials in cancer patients treated with PARP inhibitors were retrieved, and the systematic evaluation was conducted. Embase and PubMed/Medline were searched for articles published till July 2020.

RESULTS

Twenty-nine RCTs and 9529 patients were included. The present meta-analysis suggests that the use of PARP inhibitors significantly increases the risk of developing all-grade nausea (RR, 1.46; 95% CI, 1.29-1.66; p < .00001), vomiting (RR, 1.39; 95% CI, 1.17-1.64; p = .0001), diarrhoea (RR, 1.14; 95% CI, 1.06-1.23; p = .0003) and decreased appetite (RR, 1.24; 95% CI, 1.14-1.36; p < .00001), but not for constipation. And the use of these agents significantly increased the risk of high-grade nausea (RR, 1.99; 95% CI, 1.44-2.74; p < .0001), vomiting (RR, 1.54; 95% CI, 1.11-2.14; p = .01) and decreased appetite (RR, 2.03; 95% CI, 1.22-3.40; p = .007), except for diarrhoea and constipation. Nausea was the most common GI event for these agents. Patients receiving veliparib were associated with a relatively lower risk of all-grade nausea and vomiting. Patients with ovarian cancer tend to have a higher risk of all-grade nausea and vomiting than those with non-ovarian cancer. The risk of all-grade nausea and vomiting tended to be higher when PARP inhibitors treatment was longer.

WHAT IS NEW AND CONCLUSION

PARP inhibitors were associated with a significant increased risk of GI events. Clinicians should be aware of these risks and perform regular monitoring.

Further Understanding of High-Grade Serous Ovarian Carcinogenesis: Potential Therapeutic Targets

High-grade serous ovarian carcinoma (HGSOC) is the most common type of ovarian cancer and the most lethal gynecologic malignancy due to advanced stage at presentation. Recent years have witnessed progress in the therapy of HGSOC with the introduction of PARP (poly-adenosine diphosphate ribose polymerase) inhibitors and the anti-angiogenic monoclonal antibody bevacizumab to the backbone of chemotherapy or as maintenance therapy after chemotherapy. The improved molecular understanding of ovarian cancer pathogenesis, which has brought these therapies into the clinic, aspires to extend the boundaries of therapies through elucidation of other molecular aspects of ovarian carcinogenesis. This accumulating knowledge has started to be translated to additional targeted therapies that are in various stages of development. These include inhibitors of the function of other proteins involved in homologous recombination deficiency (HRD), such as WEE1 kinase, ATM/ATR kinases and CDK12 inhibitors. Despite disappointing results with immune checkpoint inhibitors monotherapy, harnessing the immune system in HGSOC with combination therapies that promote antigen production and immune cell activation is an avenue being explored. This paper examines arising HGSOC therapies based on molecular understanding of pathogenesis.

Emerging role of immune checkpoint inhibitors in the treatment of ovarian cancer

INTRODUCTION

In recent years, ovarian cancer (OC) treatment has been enriched with many new target therapies, most of all antiangiogenic drugs and PARP inhibitors (PARPis), which have literally changed the natural history of the disease. The impressive results of immunotherapy in other malignancies, mainly melanoma and lung cancer, and the good signals of activity in gynecological neoplasms like cervical and microsatellite instable (MSI-H) endometrial cancer, opened the space to the introduction of immune-stimulatory drugs in ovarian cancer.

AREA COVERED

The goal of this article is to summarize the newest evidence on the use of immune check point inhibitors in OC trying to explain why, at present, this strategy has failed to improve clinical outcome and focusing on the possible strategies to overcome treatment failure.

EXPERT OPINION

Although numerous trials have been undertaken, only scanty results have been obtained so far with immune check-point inhibitors (ICIs) in OC either when used as single agents or in combination with antiangiogenic therapy and ongoing trials are exploring the association of ICIs with PARPis and other ICIs. A better knowledge of predictive biomarkers of response and mechanisms of immunotherapy resistance, will help in identifying the most appropriate population to treat with ICIs.

The Potential Roles of Epigallocatechin-3-Gallate in the Treatment of Ovarian Cancer: Current State of Knowledge

Ovarian cancer represents the principal leading cause of women dying in the world. The first standard of care involved surgical resection followed by chemotherapy with taxane and platinum, mainly connected with cytotoxic chemotherapies causing diverse severe side effects. Unfortunately, recurrence represents a significant problem, and finally, patients develop resistance to cytotoxic chemotherapy. Other alternative treatments had been developed so far to reduce side effects; however, the outcomes are yet not empowering. Current shreds of evidence showed that epigallocatechin-3-gallate (EGCG) possesses an anticancer effect on ovarian carcinoma, mainly through the inhibition of different genetic signaling pathways which are closely linked with tumorigenesis. This review recapitulates these findings and highlights the roles of EGCG for the chemoprevention and treatment of ovarian cancer.

Programmed Death-1 Receptor (PD-1) as a Potential Prognosis Biomarker for Ovarian Cancer Patients

Aim

Ovarian cancer (OC) is one of the most lethal gynecological malignancies. Recent studies suggest a crucial role of the PD-1/PD-L1 pathway in OC pathogenesis. Therefore, our study aimed at evaluation of the clinical importance of PD-1 expression in ovarian cancer patients.

Patients and Methods

In this study, we investigated the role of PD-1 in OC patients (n=50) by analyzing its expression on CD4⁺ and CD8⁺ T cells in three OC environments: peripheral blood (PB), peritoneal fluid (PF), and tumor (TT) as well as soluble PD-1 (sPD-1) in plasma and PF in terms of their clinical and prognostic significance. T cells with PD-1 expression were analyzed using flow cytometry. The concentration of sPD-1 was determined with the use of ELISA. Our research demonstrated differences in PD-1 expression on CD4⁺ and CD8⁺ T cells in the OC environments.

Results

We found an elevated level of CD4⁺PD-1⁺ T cells in tumor and PF, compared to PB. Additionally, we found the highest percentage of CD8⁺ PD-1⁺ in tumor, compared to PB and PF. The levels of sPD-1 were higher (p<0.0001) in plasma than in PF. For the first time, we discovered that the higher level of CD4⁺PD-1⁺ T cells in the circulation and the higher sPD-1 level in plasma predict poor survival of OC patients.

Conclusion

We suggest that PD-1 could be a predictive biomarker for OC patients and successful immunotherapy.

Bcl‑2 family: Novel insight into individualized therapy for ovarian cancer (Review)

Chemoresistance to platinum‑based chemotherapy for ovarian cancer in the advanced stage remains a formidable concern clinically. Increasing evidence has revealed that apoptosis represents the terminal events of the anti‑tumor mechanisms of a number of chemical drugs and has a close association with chemoresistance in ovarian cancer. The B‑cell lymphoma‑2 (Bcl‑2) family plays a crucial role in apoptosis and has a close association with chemoresistance in ovarian cancer. Some drugs that target Bcl‑2 family members have shown efficacy in overcoming the chemoresistance of ovarian cancer. A BH3 profiling assay was found to be able to predict how primed a cell is when treated with antitumor drugs. The present review summarizes the role of the Bcl‑2 family in mediating cell death in response to antitumor drugs and novel drugs that target Bcl‑2 family members. The application of the new functional assay, BH3 profiling, is also discussed herein. Furthermore, the present review presents the hypothesis that targeting Bcl‑2 family members may prove to be helpful for the individualized therapy of ovarian cancer in clinical practice and in laboratory research.

The Role of microRNAs in Epithelial Ovarian Cancer Metastasis

Epithelial ovarian cancer (EOC) is the deadliest gynecological cancer, and the major cause of death is mainly attributed to metastasis. MicroRNAs (miRNAs) are a group of small non-coding RNAs that exert important regulatory functions in many biological processes through their effects on regulating gene expression. In most cases, miRNAs interact with the 3′ UTRs of target mRNAs to induce their degradation and suppress their translation. Aberrant expression of miRNAs has been detected in EOC tumors and/or the biological fluids of EOC patients. Such dysregulation occurs as the result of alterations in DNA copy numbers, epigenetic regulation, and miRNA biogenesis. Many studies have demonstrated that miRNAs can promote or suppress events related to EOC metastasis, such as cell migration, invasion, epithelial-to-mesenchymal transition, and interaction with the tumor microenvironment. In this review, we provide a brief overview of miRNA biogenesis and highlight some key events and regulations related to EOC metastasis. We summarize current knowledge on how miRNAs are dysregulated, focusing on those that have been reported to regulate metastasis. Furthermore, we discuss the role of miRNAs in promoting and inhibiting EOC metastasis. Finally, we point out some limitations of current findings and suggest future research directions in the field.

Sarcoma stratification by combined pH2AX and MAP17 (PDZK1IP1) levels for a better outcome on doxorubicin plus olaparib treatment

Sarcomas constitute a rare heterogeneous group of tumors, including a wide variety of histological subtypes. Despite advances in our understanding of the pathophysiology of the disease, first-line sarcoma treatment options are still limited and new treatment approaches are needed. Histone H2AX phosphorylation is a sensitive marker for double strand breaks and has recently emerged as biomarker of DNA damage for new drug development. In this study, we explored the role of H2AX phosphorylation at Ser139 alone or in combination with MAP17 protein, an inducer of DNA damage through ROS increase, as prognostic biomarkers in sarcoma tumors. Next, we proposed doxorubicin and olaparib combination as potential therapeutic strategies against sarcomas displaying high level of both markers. We evaluate retrospectively the levels of pH2AX (Ser139) and MAP17 in a cohort of 69 patients with different sarcoma types and its relationship with clinical and pathological features. We found that the levels of pH2AX and MAP17 were related to clinical features and poor survival. Next, we pursued PARP1 inhibition with olaparib to potentiate the antitumor effect of DNA damaging effect of the DNA damaging agent doxorubicin to achieve an optimal synergy in sarcoma. We demonstrated that the combination of olaparib and doxorubicin was synergistic in vitro, inhibiting cell proliferation and enhancing pH2AX intranuclear accumulation, as a result of DNA damage. The synergism was corroborated in patient-derived xenografts (PDX) where the combination was effective in tumors with high levels of pH2AX and MAP17, suggesting that both biomarkers might potentially identify patients who better benefit from this combined therapy.

Clinical outcomes and safety of apatinib monotherapy in the treatment of patients with advanced epithelial ovarian carcinoma who progressed after standard regimens and the analysis of the VEGFR2 polymorphism

The aims of the present study were to investigate the clinical outcomes and safety of apatinib monotherapy in the treatment of patients with advanced epithelial ovarian carcinoma (EOC) who have progressed after standard regimens, and to analyze the vascular endothelial growth factor receptor 2 (VEGFR2) rs2071559 polymorphism. A total of 118 patients with advanced EOC who received apatinib treatment were included in the study. Tumor response was evaluated using progression-free survival (PFS) and overall survival (OS) time, and safety data were documented. Additionally, peripheral blood and peripheral blood mononuclear cell (PBMC) specimens from the patients with EOC were collected to perform the genotyping of genetic polymorphism and assess the mRNA expression of VEGFR2, respectively. The objective response rate across the 118 patients with advanced EOC was 38.98%, the disease control rate was 63.56%, the median PFS time was 4.65 months and the median OS time was 15.10 months. Regarding the polymorphism analysis, the prevalence of rs2071559 in VEGFR2 among the 118 patients with advanced EOC was recorded as the TT genotype in 72 cases (61.02%), TC genotype in 41 cases (34.75%) and CC genotype in 5 cases (4.23%), and the minor allele frequency of rs2071559 was 0.22. The distribution of the three genotypes was in accordance with the Hardy-Weinberg equilibrium (P=0.781). TC and CC genotypes were merged in the subsequent analysis. The prognosis analyses suggested that the median PFS time of patients with the TC/CC genotype and the TT genotype was 3.10 and 5.40 months, respectively (P=0.015). Moreover, the median OS time of the two genotypes was 12.60 and 17.50 months, respectively (P=0.009). However, no association was noted between genotype status of the polymorphism and adverse reactions. Additionally, the mRNA expression analysis indicated that the mRNA expression levels of VEGFR2 in PBMC specimens were significantly different between TT and TC/CC genotypes (P<0.001). The present study suggested that the clinical outcomes of patients with advanced EOC, who progressed after standard regimens and received apatinib treatment, might be influenced by the VEGFR2 rs2071559 polymorphism.

DNA Repair and Ovarian Carcinogenesis: Impact on Risk, Prognosis and Therapy Outcome

There is ample evidence for the essential involvement of DNA repair and DNA damage response in the onset of solid malignancies, including ovarian cancer. Indeed, high-penetrance germline mutations in DNA repair genes are important players in familial cancers: BRCA1, BRCA2 mutations or mismatch repair, and polymerase deficiency in colorectal, breast, and ovarian cancers. Recently, some molecular hallmarks (e.g., TP53, KRAS, BRAF, RAD51C/D or PTEN mutations) of ovarian carcinomas were identified. The manuscript overviews the role of DNA repair machinery in ovarian cancer, its risk, prognosis, and therapy outcome. We have attempted to expose molecular hallmarks of ovarian cancer with a focus on DNA repair system and scrutinized genetic, epigenetic, functional, and protein alterations in individual DNA repair pathways (homologous recombination, non-homologous end-joining, DNA mismatch repair, base- and nucleotide-excision repair, and direct repair). We suggest that lack of knowledge particularly in non-homologous end joining repair pathway and the interplay between DNA repair pathways needs to be confronted. The most important genes of the DNA repair system are emphasized and their targeting in ovarian cancer will deserve further attention. The function of those genes, as well as the functional status of the entire DNA repair pathways, should be investigated in detail in the near future.

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.

Wise Management of Ovarian Cancer: On the Cutting Edge

Epithelial ovarian cancer (EOC) is the fifth leading cause of cancer mortality among women. Two-thirds of patients present at advanced stage at diagnosis, and the estimated 5 year survival rate is 20-40%. This heterogeneous group of malignancies has distinguishable etiology and molecular biology. Initially, single-gene sequencing was performed to identify germline DNA variations associated with EOC. However, hereditary EOC syndrome can be explained by germline pathogenic variants (gPVs) in several genes. In this regard, next-generation sequencing (NGS) changed clinical diagnostic testing, allowing assessment of multiple genes simultaneously in a faster and cheaper manner than sequential single gene analysis. As we move into the era of personalized medicine, there is evidence that poly (ADP-ribose) polymerase (PARP) inhibitors exploit homologous recombination (HR) deficiency, especially in breast cancer gene 1 and 2 (BRCA1/2) mutation carriers. Furthermore, extensive preclinical data supported the development of aurora kinase (AURK) inhibitors in specific tumor types, including EOC. Their efficacy may be optimized in combination with chemotherapeutic or other molecular agents. The efficacy of metformin in ovarian cancer prevention is under investigation. Certain mutations, such as ARID1A mutations, and alterations in the phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR pathway, which are specific in ovarian clear cell carcinoma (OCCC) and endometrioid ovarian carcinoma (EnOC), may offer additional therapeutic targets in these clinical entities. Malignant ovarian germ cell tumors (MOGCTs) are rare and randomized trials are extremely challenging for the improvement of the existing management and development of novel strategies. This review attempts to offer an overview of the main aspects of ovarian cancer, catapulted from the molecular mechanisms to therapeutic considerations.

Clinical Implications of DNA Repair Defects in High-Grade Serous Ovarian Carcinomas

Despite significant improvements in surgical and medical management, high grade serous ovarian cancer (HGSOC) still represents the deadliest gynecologic malignancy and the fifth most frequent cause of cancer-related mortality in women in the USA. Since DNA repair alterations are regarded as the “the Achille’s heel” of HGSOC, both DNA homologous recombination and DNA mismatch repair deficiencies have been explored and targeted in epithelial ovarian cancers in the latest years. In this review, we aim at focusing on the therapeutic issues deriving from a faulty DNA repair machinery in epithelial ovarian cancers, starting from existing and well-established treatments and investigating new therapeutic approaches which could possibly improve ovarian cancer patients’ survival outcomes in the near future. In particular, we concentrate on the role of both Poly (ADP-ribose) Polymerase (PARP) inhibitors (PARPis) and immune checkpoint inhibitors in HGSOC, highlighting their activity in relation to BRCA1/2 mutational status and homologous recombination deficiency (HRD). We investigate the biological rationale supporting their use in the clinical setting, pointing at tracking their route from the laboratory bench to the patient’s bedside. Finally, we deal with the onset of mechanisms of primary and acquired resistance to PARPis, reporting the pioneering strategies aimed at converting homologous-recombination (HR) proficient tumors into homologous recombination (HR)-deficient HGSOC.

Azasteroid Alkylators as Dual Inhibitors of AKT and ERK Signaling for the Treatment of Ovarian Carcinoma

(1) Background: Previous findings show that lactam steroidal alkylating esters display improved therapeutic efficacy with reduced toxicity. The aim of this study was to evaluate the anticancer activity of two newly synthesized aza-steroid alkylators (ENGA-L06E and ENGA-L08E) against human ovarian carcinoma cells, and consequently, the dual inhibition of RAS/PI3K/AKT and RAS/RAF/MEK/ERK signaling pathways, both of which are closely associated with ovarian cancer; (2) Methods: The in vitro cytostatic and cytotoxic effects of ENGA-L06E and ENGA-L08E were evaluated in a panel of five human ovarian cancer cell lines, as well as in in vivo studies. ENGA-L06E and ENGA-L08E, in addition to another two aniline-mustard alkylators, POPAM and melphalan (L-PAM), were utilized in order to determine the acute toxicity and antitumor efficacy on two human ovarian xenograft models. Also, in silico studies were performed in order to investigate the dual inhibition of ENGA-L06E and ENGA-L08E on RAS/PI3K/AKT and RAS/RAF/MEK/ERK signaling pathways; (3) Results: Both, in vitro and in vivo studies demonstrated that ENGA-L06E and ENGA-L08E were significantly more effective with a lower toxicity profile in comparison to POPAM and L-PAM alkylators. Moreover, in silico studies demonstrated that the two new aza-steroid alkylators could act as efficient inhibitors of the phosphorylation of AKT and ERK1/2 molecules; and (4) Conclusions: Both ENGA-L06E and ENGA-L08E demonstrated high anticancer activity through the inhibition of the PI3K-AKT and KRAS-ERK signaling pathways against human ovarian carcinoma, and thus constituting strong evidence towards further clinical development.

Comparing Paclitaxel-Carboplatin with Paclitaxel-Cisplatin as the Front-Line Chemotherapy for Patients with FIGO IIIC Serous-Type Tubo-Ovarian Cancer

The use of weekly chemotherapy for the treatment of patients with advanced-stage serous-type epithelial Tubo-ovarian cancer (ETOC), and primary peritoneal serous carcinoma (PPSC) is acceptable as the front-line postoperative chemotherapy after primary cytoreductive surgery (PCS). The main component of dose-dense chemotherapy is weekly paclitaxel (80 mg/m²), but it would be interesting to know what is the difference between combination of triweekly cisplatin (20 mg/m²) or triweekly carboplatin (carboplatin area under the curve 5-7 mg/mL per min [AUC 5-7]) in the dose-dense paclitaxel regimen. Therefore, we compared the outcomes of women with Gynecology and Obstetrics (FIGO) stage IIIC ETOC and PPSC treated with PCS and a subsequent combination of dose-dense weekly paclitaxel and triweekly cisplatin (paclitaxel–cisplatin) or triweekly carboplatin using AUC 5 (paclitaxel–carboplatin). Between January 2010 and December 2016, 40 women with International Federation of Gynecology and Obstetrics (FIGO) stage IIIC EOC, FTC, or PPSC were enrolled, including 18 treated with paclitaxel–cisplatin and the remaining 22 treated with paclitaxel–carboplatin. There were no statistically significant differences in disease characteristics of patients between two groups. Outcomes in paclitaxel–cisplatin group seemed to be little better than those in paclitaxel–carboplatin (median progression-free survival [PFS] 30 versus 25 months as well as median overall survival [OS] 58.5 versus 55.0 months); however, neither reached a statistically significant difference. In terms of adverse events (AEs), patients in paclitaxel–carboplatin group had more AEs, with a higher risk of neutropenia and grade 3/4 neutropenia, and the need for a longer period to complete the front-line chemotherapy, and the latter was associated with worse outcome for patients. We found that a period between the first-time chemotherapy to the last dose (6 cycles) of chemotherapy >21 weeks was associated with a worse prognosis in patients compared to that ≤21 weeks, with hazard ratio (HR) of 81.24 for PFS and 9.57 for OS. As predicted, suboptimal debulking surgery (>1 cm) also contributed to a worse outcome than optimal debulking surgery (≤1 cm) with HR of 14.38 for PFS and 11.83 for OS. Based on the aforementioned findings, both regimens were feasible and effective, but maximal efforts should be made to achieve optimal debulking surgery and following the on-schedule administration of dose-dense weekly paclitaxel plus triweekly platinum compounds. Randomized trials validating the findings are warranted.

Neutrophil Extracellular Trap Formation Correlates with Favorable Overall Survival in High Grade Ovarian Cancer

It is still a question of debate whether neutrophils, often found in the tumor microenvironment, mediate tumor-promoting or rather tumor-inhibiting activities. The present study focuses on the involvement of neutrophils in high grade serous ovarian cancer (HGSOC). Macroscopic features classify two types of peritoneal tumor spread in HGSOC. Widespread and millet sized lesions characterize the miliary type, while non-miliary metastases are larger and associated with better prognosis. Multi-omics and FACS data were generated from ascites samples. Integrated data analysis demonstrates a significant increase of neutrophil extracellular trap (NET)-associated molecules in non-miliary ascites samples. A co-association network analysis performed with the ascites data further revealed a striking correlation between NETosis-associated metabolites and several eicosanoids. The congruence of data generated from primary neutrophils with ascites analyses indicates the predominance of NADPH oxidase 2 (NOX)-independent NETosis. NETosis is associated with protein S100A8/A9 release. An increase of the S100A8/CRP abundance ratio was found to correlate with favorable survival of HGSOC patients. The analysis of additional five independent proteome studies with regard to S100A8/CRP ratios confirmed this observation. In conclusion, NET formation seems to relate with better cancer patient outcome.

Weekly Dose-Dense Paclitaxel and Triweekly Low-Dose Cisplatin: A Well-Tolerated and Effective Chemotherapeutic Regimen for First-Line Treatment of Advanced Ovarian, Fallopian Tube, and Primary Peritoneal Cancer

A combination of cytoreductive surgery, either primary (PCS) or interval (ICS), and chemotherapy with a platinum-paclitaxel regimen is the well-accepted treatment for advanced-stage epithelial ovarian cancer (EOC), fallopian tube cancer (FTC), and primary peritoneal serous carcinoma (PPSC), but it is still uncertain whether a combination of dose-dense weekly paclitaxel and low-dose triweekly cisplatin is useful in the management of these patients. Therefore, we retrospectively evaluated the outcomes of women with advanced-stage EOC, FTC, and PPSC treated with PCS and subsequent dose-dense weekly paclitaxel (80 mg/m²) and low-dose triweekly cisplatin (20 mg/m²). Between January 2011 and December 2017, 32 women with International Federation of Gynecology and Obstetrics (FIGO) stage IIIC–IV EOC, FTC, or PPSC were enrolled. Optimal PCS was achieved in 63.5% of patients. The mean and median progression-free survival was 36.5 and 27.0 months, respectively (95% confidence interval (CI): 26.8–46.2 and 11.3–42.7 months, respectively). The mean overall survival was 56.0 months (95% CI: 43.9–68.1 months), and the median overall survival could not be obtained. The most common all-grade adverse events (AEs) were anemia (96.9%), neutropenia (50%), peripheral neuropathy (28.1%), nausea and vomiting (34.4%), and thrombocytopenia (15.6%). These AEs were predominantly grade 1/2, and only a few patients were complicated by grade 3/4 neutropenia (21.9%) and anemia (6.3%). A multivariate analysis indicated that only suboptimal PCS was significantly correlated with a worse prognosis, resulting in an 11.6-fold increase in the odds of disease progression. In conclusion, our data suggest that dose-dense weekly paclitaxel (80 mg/m²) combined with low-dose triweekly cisplatin (20 mg/m²) is a potentially effective and highly tolerable front-line treatment in advanced EOC, FTC, and PPSC. Randomized trials comparing the outcome of this regimen to other standard therapies for FIGO stage IIIC–IV EOC, FTC, and PPSC are warranted.

The Association and Significance of p53 in Gynecologic Cancers: The Potential of Targeted Therapy

Dysfunction of p53 is observed in the many malignant tumors. In cervical cancer, p53 is inactivated by degradation through the complex with human papilloma virus (HPV) oncoprotein E6 and E6-associated protein (E6AP), an E3 ubiquitin protein ligase. In endometrial cancer, overexpression of p53 in immunohistochemistry is a significant prognostic factor. A discrepancy between p53 overexpression and TP53 mutations is observed in endometrioid endometrial cancer, indicating that the accumulation of p53 protein can be explained by not only gene mutations but also dysregulation of the factors such as ERβ and MDM2. Furthermore, the double-positive expression of immunoreactive estrogen receptor (ER) β and p53 proteins is closely associated with the incidence of metastasis and/or recurrence. High-grade serous ovarian carcinoma (HGSC) arises from secretary cells in the fallopian tube. The secretary cell outgrowth (SCOUT) with TP53 mutations progresses to HGSC via the p53 signature, serous intraepithelial lesion (STIL), and serous intraepithelial carcinoma (STIC), indicating that TP53 mutation is associated with carcinogenesis of HGSC. Clinical application targeting p53 has been approved for some malignant tumors. Gene therapy by the adenovirus-mediated p53 gene transfer system is performed for head and neck cancer. A clinical phase III trial using MDM2/X inhibitors, idasanutlin (RG7388) combined with cytarabine, is being performed involving relapse/refractory acute myeloid leukemia patients. The use of adenoviruses as live vectors which encode wild-type p53 has given promising results in cervical cancer patients.

BRCA1/2 Molecular Assay for Ovarian Cancer Patients: A Survey through Italian Departments of Oncology and Molecular and Genomic Diagnostic Laboratories

In Italy, 5200 new ovarian cancers were diagnosed in 2018, highlighting an increasing need to test women for BRCA1/2. The number of labs offering this test is continuously increasing. The aim of this study was to show the results coming from the intersociety survey coordinated by four different Clinical and Laboratory Italian Scientific Societies (AIOM, SIAPEC-IAP, SIBIOC, and SIGU). A multidisciplinary team belonging to the four scientific societies drew up two different questionnaires: One was targeted toward all Italian Departments of Medical Oncology, and the second toward laboratories of clinical molecular biology. This survey was implemented from September 2017 to March 2018. Seventy-seven out of 305 (25%) Departments of Medical Oncology filled our survey form. Indeed, 59 molecular laboratories were invited. A total of 41 laboratories (70%) filled in the questionnaire. From 2014 to 2017, 16 new molecular laboratories were activated. A total of 12,559 tests were performed in the year 2016, with a mean of 339 tests and a median of 254 tests per laboratory, showing a glimpse of an extreme low number of tests performed per year by some laboratories. In terms of the type and number of professionals involved in the pre- and post-test counseling, results among the onco-genetic team were heterogeneous. Our data show that the number of laboratories providing BRCA1/2 germline assays is significantly increased with further implementation of the somatic test coming soon. The harmonization of the complete laboratory diagnostic path should be encouraged, particularly in order to reduce the gap between laboratories with high and low throughput.