Maintenance olaparib for patients with newly diagnosed advanced ovarian cancer and a BRCA mutation (SOLO1/GOG 3004): 5-year follow-up of a randomised, double-blind, placebo-controlled, phase 3 trial

DNA repair and the contribution to chemotherapy resistance

The DNA damage response comprises a set of imperfect pathways that maintain cell survival following exposure to DNA damaging agents. Cancers frequently exhibit DNA repair pathway alterations that contribute to their intrinsic genome instability. This, in part, facilitates a therapeutic window for many chemotherapeutic agents whose mechanisms of action often converge at the generation of a double-strand DNA break. The development of therapy resistance occurs through countless molecular mechanisms that promote tolerance to DNA damage, often by preventing break formation or increasing repair capacity. This review broadly discusses the DNA damaging mechanisms of action for different classes of chemotherapeutics, how avoidance and repair of double-strand breaks can promote resistance, and strategic directions for counteracting therapy resistance.

Role of tumor microenvironment in ovarian cancer metastasis and clinical advancements

Ovarian cancer (OC) is the most lethal gynecological malignancy worldwide, characterized by heterogeneity at the molecular, cellular and anatomical levels. Most patients are diagnosed at an advanced stage, characterized by widespread peritoneal metastasis. Despite optimal cytoreductive surgery and platinum-based chemotherapy, peritoneal spread and recurrence of OC are common, resulting in poor prognoses. The overall survival of patients with OC has not substantially improved over the past few decades, highlighting the urgent necessity of new treatment options. Unlike the classical lymphatic and hematogenous metastasis observed in other malignancies, OC primarily metastasizes through widespread peritoneal seeding. Tumor cells (the "seeds") exhibit specific affinities for certain organ microenvironments (the "soil"), and metastatic foci can only form when there is compatibility between the "seeds" and "soil." Recent studies have highlighted the tumor microenvironment (TME) as a critical factor influencing the interactions between the "seeds" and "soil," with ascites and the local peritoneal microenvironment playing pivotal roles in the initiation and progression of OC. Prior to metastasis, the interplay among tumor cells, immunosuppressive cells, and stromal cells leads to the formation of an immunosuppressive pre-metastatic niche in specific sites. This includes characteristic alterations in tumor cells, recruitment and functional anomalies of immune cells, and dysregulation of stromal cell distribution and function. TME-mediated crosstalk between cancer and stromal cells drives tumor progression, therapy resistance, and metastasis. In this review, we summarize the current knowledge on the onset and metastatic progression of OC. We provide a comprehensive discussion of the characteristics and functions of TME related to OC metastasis, as well as its association with peritoneal spread. We also outline ongoing relevant clinical trials, aiming to offer new insights for identifying potential effective biomarkers and therapeutic targets in future clinical practice.

Identification and impact of microbiota-derived metabolites in ascites of ovarian and gastrointestinal cancer

BACKGROUND

Malignant ascites is a common complication of advanced ovarian cancer (OC) and gastrointestinal cancer (GI), significantly impacting metastasis, quality of life, and survival. Increased intestinal permeability can lead to blood or lymphatic infiltration and microbial translocation from the gastrointestinal or uterine tract. This study aimed to identify microbiota-derived metabolites in ascites from OC (stages II-III and IV) and GI patients, assessing their roles in tumor progression.

METHODS

Malignant ascites samples from 18 OC and GI patients were analyzed using a four-dimensional (4D) untargeted metabolomics approach combining reversed-phase (RP) and hydrophilic interaction liquid chromatography (HILIC) with trapped ion mobility spectrometry time-of-flight mass spectrometry (timsTOF-MS). Additonally, a targeted flow cytometry-based cytokine panel was used to screen for inflammatory markers. Non-endogenous, microbiota-derived metabolites were identified through the Human Microbial Metabolome Database (MiMeDB).

RESULTS

OC stage IV exhibited metabolic profiles similar to GI cancers, while OC stage II-III differed significantly. Stage IV OC patients exhibited higher levels of 11 typically microbiome-derived metabolites, including 1-methylhistidine, 3-hydroxyanthranilic acid, 4-pyridoxic acid, biliverdin, butyryl-L-carnitine, hydroxypropionic acid, indole, lysophosphatidylinositol 18:1 (LPI 18:1), mevalonic acid, N-acetyl-L-phenylalanine, and nudifloramide, and lower levels of 5 metabolites, including benzyl alcohol, naringenin, o-cresol, octadecanedioic acid, and phenol, compared to stage II-III. Correlation analysis revealed positive associations between IL-10 and metabolites such as glucosamine and LPCs, while MCP-1 positively correlated with benzyl alcohol and phenol.

CONCLUSION

4D metabolomics revealed distinct metabolic signatures in OC and GI ascites, highlighting microbiota-derived metabolites involved in lipid metabolism and inflammation. Metabolites like 3-hydroxyanthranilic acid, indole, and naringenin may serve as markers of disease progression and underscore the microbiota's role in shaping malignant ascites and tumor biology.

PARP Inhibitors in Ovarian Cancer: Resistance Mechanisms, Clinical Evidence, and Evolving Strategies

The introduction of poly (ADP-ribose) polymerase inhibitors (PARPi) into the management of ovarian cancer has transformed the treatment landscape for patients affected by this malignancy. However, as the use of PARPi expands into both frontline maintenance and recurrence settings, the emergence of drug resistance has become a significant clinical challenge in the treatment of these patients. Although platinum-based chemotherapy (PBC) and PARPi act through different mechanisms-PBC causes DNA damage while PARPi blocks its repair-both depend on the integrity of DNA damage repair (DDR) pathways, leading to overlapping mechanisms of resistance. Here, we review the key resistance mechanisms shared by PARPi and PBC, and then we discuss their clinical implications in the management of patients with ovarian cancer. We also examine clinical rationale supporting the hypothesis that prior PARPi exposure may reduce the efficacy of subsequent PBC in patients experiencing a disease recurrence. Furthermore, we review preliminary clinical data assessing the potential role of PARPi retreatment in patients who have previously progressed on PARPis.

Oncologist perceptions of "cure" and long-term management in advanced ovarian cancer in the United States: results from a cross-sectional survey

OBJECTIVES

Treatment advancements have improved survival outcomes for patients with advanced ovarian cancer. In advanced ovarian cancer, some physicians believe discussing "cure" as a potential treatment goal may be premature. In contrast, others note that the durable responses observed among some patients may suggest that long-term remission or "cure" are legitimate outcomes to strive for. Despite this, the term 'cure' has no accepted definition in this setting, and whether physicians are willing to use this language is unknown.

METHODS

A cross-sectional, internet-based survey was conducted to evaluate United States oncologists' attitudes and beliefs related to "cure" in the context of treating patients with newly diagnosed advanced ovarian cancer. The survey included questions on attitudes and beliefs toward patient prognosis with newly diagnosed advanced ovarian cancer, oncologists' perceptions of clinical outcomes, oncologist characteristics, and clinical practice details.

RESULTS

Among 150 oncologists, when addressing the topic of disease prognosis or treatment goals in patients newly diagnosed with stage III-IV ovarian cancer, the terms endorsed by more than half of oncologists were "achieve long-term remission" and "achieve long-term response." Terms including "cure" or "curable" were endorsed by less than 35% of oncologists. Among several patient characteristics evaluated, no evidence of disease for 5 to 10 years was most indicative of cure. In the context of primary disease, the proportion of oncologists who would tell a patient with advanced ovarian cancer they were cured, even if they believe it to be true, decreased with the stage (II = 73.8%; III = 60.8%; IV = 50.5%).

CONCLUSIONS

The current study found that while oncologists may believe a cure is possible across early stages of ovarian cancer, many remain hesitant to discuss the potential of "cure" with patients, particularly those with stage IV disease.

Complete remission of endometrial cancer stage IVC treated with multimodality treatment including immunotherapy and maintenance PARP inhibitor - A case report

OBJECTIVE

Mismatched repair (MMR) deficient, stage IVC endometrial carcinoma (EC) are occasionally reported as cured by immune-checkpoint inhibitors (ICIs). We present an MMR proficient (MMRp) case with long-term survival.

CASE REPORT

The patient was diagnosed with EC (endometrioid, grade 3, MMRp, programmed death-ligand 1 positive) stage IVC (lung, spine/pelvic bone, paraaortic, pelvic, inguinal and presacral node metastases) with tumor extended from endometrium to cervix, vagina to vulva. After responded to chemoimmunotherapy with paclitaxel/carboplatin then liposomal doxorubicin/carboplatin, pembrolizumab and radiotherapy to pelvis/pelvic bone metastasis, the patient received definitive surgery which showed only residual EC. Olaparib was used as maintenance therapy. The patient developed isolated recurrence in presacral lymph node 2.5 years later, she underwent proton therapy and got complete remission again and maintained with olaparib. She is currently without disease 31 months since recurrence.

CONCLUSION

Initial stage IVC MMRp EC with recurrence is still potentially curable with multimodality treatment including ICI.

External validation of prediction models for early relapse in advanced epithelial ovarian cancer using Australian and Dutch population-based data

OBJECTIVE

To externally validate the published postoperative and BRCA models predictive of early relapse in patients with advanced-stage epithelial ovarian cancer (EOC) using independent Australian and Dutch cohorts.

METHODS

Advanced-stage EOC patients diagnosed between January 1, 2002, and June 1, 2006, in Australia, and between January 1, 2016, and December 31, 2017, in the Netherlands were included. Data from patients who underwent cytoreductive surgery and platinum-based chemotherapy were used to validate both models. Missing data were addressed through multiple imputation. Model updates included recalibration-in-the-large, recalibration, and model revision, with a closed testing procedure to identify the most suitable approach. Model performance was assessed for calibration, discrimination, and the Brier score.

RESULTS

The Australian cohort (N = 1334) included 457 early relapsers and 859 late or non-relapsers, showing baseline differences compared to the development cohort. Discrimination was adequate for both the postoperative and BRCA models (c-statistics: 0.69 and 0.70, respectively). The postoperative model required full revision, while recalibration-in-the-large was sufficient for the BRCA model in the Australian cohort. The Dutch cohort (N = 1212) included 283 early relapsers and 929 late or non-relapsers, with baseline characteristics similar to those of the development cohort. Both models demonstrated adequate discrimination (c-statistics: 0.71 and 0.70, respectively). Recalibration-in-the-large corrected miscalibration in the Dutch cohort.

CONCLUSION

The postoperative and BRCA model were successfully validated for predicting early relapse in advanced-stage EOC patients, confirming their robustness. However, local data updates are advised to enhance accuracy across clinical settings. Online calculators were built for clinical use (Link 1; Link 2).

The combination of BET and METTL3 inhibitors elicits synergistic antitumor effects in ovarian cancer cells via reducing SP1 and BCL-2 expression

Ovarian cancer (OC) remains a major health threat to woman despite treatment advances. New therapeutic strategies are demanded to persistently explored. In this study, we found that inhibitors of bromodomain and extra-Terminal domain (BET) and methyltransferase-like 3 (METTL3) exerted synergistic proliferative inhibition in different OC cell lines. In vitro synergism was translated into in vivo antitumor activity through the combination of BET inhibitor HJP-178 and METTL3 inhibitor STM2457. Mechanistically, this combination mainly enhanced apoptosis rather than affecting cell cycle arrest. Furthermore, it was revealed that HJP-178 decreased the transcription of Specificity protein 1 (SP1) while STM2457 lowered the N6-methyladenosine (m6A) levels of SP1 mRNA. Consequently, their combination synergistically reduces SP1 RNA and protein levels through both transcriptional and post-transcriptional modifications. Further exploration demonstrated that inhibiting SP1 directly downregulates the anti-apoptotic protein B-cell lymphoma-2 (BCL-2), activating the caspase-mediated apoptotic pathway and triggering programmed cell death. Importantly, SP1 overexpression significantly reducing the apoptosis induction and proliferation inhibition induced by the combination. Similarly, BCL-2 overexpression mimicked the effects of increased SP1. These results demonstrate the critical roles of SP1 and BCL-2 in the synergistic antitumor activity between BET and METTL3 inhibitors. Collectively, our findings broaden the potential applications of both drug types and present a promising therapeutic approach for OC, warranting further investigation in clinical settings.

PARP Inhibitors in the Neoadjuvant Setting; A Comprehensive Overview of the Rationale for their Use, Past and Ongoing Clinical Trials

PURPOSEOF REVIEW

Poly (ADP-ribose) polymerases (PARPs) are enzymes essential for detecting and repairing DNA damage through poly-ADP-ribosylation. In cancer, cells with deficiencies in homologous recombination repair mechanisms often become more dependent on PARP-mediated repair mechanisms to effectively repair dsDNA breaks. As such, PARP inhibitors (PARPis) were introduced into clinical practice, serving as a key targeted therapy option through synthetic lethality in the treatment of cancers with homologous recombination repair deficiency (HRD). Though PARPis are currently approved in the adjuvant setting for several cancer types such as ovarian, breast, prostate and pancreatic cancer, their potential role in the neoadjuvant setting remains under investigation. This review outlines the rationale for using PARPi in the neoadjuvant setting and evaluates findings from early and ongoing clinical trials.

RECENT FINDINGS

Our analysis indicates that numerous studies have explored PARPi as a neoadjuvant treatment for HRD-related cancers. The majority of neoadjuvant PARPi trials have been performed in breast and ovarian cancer, while phase II/III evidence supporting efficacy in prostate and pancreatic cancers remains limited. Studies are investigating PARPi in the neoadjuvant setting of HRD-related cancers. Future research should prioritize combination strategies with immune checkpoint inhibitors and expand outcome measures to include patient satisfaction and quality-of-life metrics.

PARP inhibitors in ovarian cancer: Mechanisms of resistance and implications to therapy

Advanced epithelial ovarian cancer of the high-grade serous subtype (HGSOC) remains a significant clinical challenge due to the development of resistance to current platinum-based chemotherapies. PARP1/2 inhibitors (PARPi) exploit the well-characterised homologous recombination repair deficiency (HRD) in HGSOC and offer an effective targeted approach to treatment. Several clinical trials demonstrated that PARPi (olaparib, rucaparib, niraparib) significantly improved progression-free survival (PFS) in HGSOC in the recurrent maintenance setting. However, 40-70 % of patients develop Resistance to PARPi presenting an ongoing challenge in the clinic. Therefore, there is an unmet need for novel targeted therapies and biomarkers to identify intrinsic or acquired resistance to PARPi in ovarian cancer. Understanding the mechanisms of resistance to PARPi is crucial for identifying molecular vulnerabilities, developing effective biomarkers for patient stratification and guiding treatment decisions. Here, we summarise the current landscape of mechanisms associated with PARPi resistance such as restored homologous recombination repair functionality, replication fork stability and alterations to PARP1 and PARP2 and the DNA damage response. We highlight the role of circulating tumour DNA (ctDNA) in identifying acquired resistance biomarkers and its potential in guiding 'real-time' treatment decisions. Moreover, we explore other innovative treatment strategies aimed at overcoming specific resistance mechanisms, including the inhibition of ATR, WEE1 and POLQ. We also examine the role of PARPi rechallenge in patients with acquired resistance.

Breast cancer surveillance for epithelial ovarian cancer patients with BRCA1 and BRCA2 pathogenic variants: a single-center retrospective study

OBJECTIVES

To identify a method for breast cancer (BC) surveillance in patients with epithelial ovarian cancer (EOC) with germline BRCA1/2 pathogenic variants (gBRCA1/2m) and the incidence of BC after EOC in the era of broad PARP inhibitors use.

METHODS

We retrospectively analyzed the data on EOC patients who had gBRCA1/2m by genetic testing between January 2017 and August 2023 in our single center.

RESULTS

Of 125 patients with EOC, 33 had gBRCA1/2m. Of these, 27 (81.8%) underwent BC surveillance, 20 ultrasound and/or mammography, and seven magnetic resonance imaging (MRI). The median time from EOC diagnosis to the initiation of BC surveillance was 8 months. EOC recurrence was significantly lower in the group with MRI than in the group without MRI (no case vs. 10 cases, P = .0261). The duration from EOC diagnosis to the start of BC surveillance was longer in the group with MRI than in the group without MRI (21 vs. 7 months, P = .1033). Two (6.1%) patients developed BC after EOC. Both cases were early stage, triple-negative BCs that occurred more than 3 years after the diagnosis of stage III EOC.

CONCLUSIONS

With the advent of PARP inhibitors, long-term survival is expected to increase, and a certain number of patients with EOC after initial treatment may benefit from BC surveillance using MRI. In particular, BC surveillance with MRI may be considered for patients who have not experienced EOC recurrence for more than 2 years.

SOX5 inhibition overcomes PARP inhibitor resistance in BRCA-mutated breast and ovarian cancer

Poly (ADP-ribose) polymerase (PARP) inhibitors are effective in cells with homologous recombination (HR) deficiency, including BRCA1/2 mutation. However, PARP inhibitors remain a therapeutic challenge in breast and ovarian cancer due to inevitably acquired resistance in most cases. Therefore, strategies to overcome PARP inhibitor resistance are unmet clinical need. SRY-box transcription factor 5 (SOX5) plays a crucial role in development of various cancers but the role of SOX5 in PARP inhibitor resistance is poorly understood. This study identified SOX5 as a potential biomarker associated with PARP inhibitor resistance and addressed potential treatment strategies to overcome PARP inhibitor resistance using the olaparib-resistant preclinical model. We observed that SOX5 was significantly upregulated in olaparib-resistant cells and contributed to PARP inhibitor resistance by upregulating DNA repair pathway genes. Ectopic SOX5 overexpression contributed to PARP inhibitor resistance by suppressing DNA double-strand breaks (DSBs) in BRCA-mutated breast and ovarian cancer. SOX5 small interfering RNA combined with olaparib sensitized olaparib-resistant cells and suppressed the growth of olaparib-resistant xenografts in mice via increased DSBs represented by ɣH2AX formation. Mechanistically, SOX5 directly interacted with yes-associated protein 1 (YAP1) and promoted its nuclear translocation by suppressing the Hippo pathway. YAP1, in association with TEA domain family members (TEAD), upregulated HR-related gene expression and conferred PARP inhibitor resistance. Furthermore, the clinical relevance of SOX5 as a therapeutic target was supported by a significant association between SOX5 overexpression and poor prognosis in ovarian cancer on public mRNA microarray data sets. Therefore, we propose SOX5 as a promising therapeutic target for overcoming PARP inhibitor resistance in BRCA1/2-mutated breast and ovarian cancer.

Clinical differences among the PARP inhibitors in the first-line treatment of advanced-stage ovarian carcinoma

INTRODUCTION

Despite favorable patient response rates to first-line chemotherapy, 5-year overall survival rates in ovarian cancer are dismal. Fortunately, the inclusion of PARP inhibitors (e.g. olaparib, niraparib, and rucaparib) following the completion of primary induction chemotherapy, has conferred improved progression-free survival rates.

AREAS COVERED

There are treatment outcome differences among the various PARP inhibitors that coincide with a patient's specific homologous recombination deficit (HRD) status; moreover, only single-agent olaparib and olaparib with bevacizumab have conferred a 5-year overall survival benefit. In the current review, we recount the clinical differences associated with the available PARP inhibitors in the management of advanced-stage ovarian carcinoma.

EXPERT OPINION

The inclusion of PARP inhibitors has significantly improved survival benefits in advanced-stage ovarian cancer, especially among patients with an identifiable HRD. While there are tolerability differences inherent to the specific PARP inhibitors, not to mention approval distinctions, olaparib is the only PARP inhibitor that has demonstrated consistent overall survival benefits.

Perspectives on cancer therapy-synthetic lethal precision medicine strategies, molecular mechanisms, therapeutic targets and current technical challenges

In recent years, synthetic lethality has become an important theme in the field of targeted cancer therapy. Synthetic lethality refers to simultaneous defects in two or more genes leading to cell death, whereas defects in any single gene do not lead to cell death. Taking advantage of the genetic vulnerability that exists within cancer cells, it theoretically has no negative impact on healthy cells and has fewer side effects than non-specific chemotherapy. Currently, targeted cancer therapies focus on inhibiting key pathways in cancer. However, it has been found that over-activation of oncogenic-related signaling pathways can also induce cancer cell death, which is a major breakthrough in the new field of targeted therapies. In this review, we summarize the conventional gene targets in synthetic lethality (PARP, ATR, ATM, WEE1, PRMT) and provide an in-depth analysis of their latest potential mechanisms. We explore the impact of over-activation of pathways such as PI3K/AKT, MAPK, and WNT on cancer cell survival, and present the technical challenges of current research. Important theoretical foundations and insights are provided for the application of synthetic lethal strategies in cancer therapy, as well as future research directions.

Comparison Study of the Safety Profile of Olaparib Versus Niraparib: Analysis of Real-World Data from EudraVigilance

Background: Olaparib and niraparib are poly (ADP-ribose) polymerase inhibitors (PARPi) used primarily for the treatment of ovarian cancer. While both drugs have demonstrated efficacy in clinical trials, their safety profiles, particularly in real-world clinical settings, remain to be fully elucidated. Objectives: This study aimed to (i) characterize the adverse drug reactions (ADRs) associated with olaparib and niraparib as reported in the EudraVigilance database, (ii) compare the frequency of the ADRs occurring during treatment with the two drugs, and (iii) compare post-marketing safety data with those from clinical trials. Methods: A retrospective analysis was performed using data from the EudraVigilance database (2017-2024), focusing on individual case safety reports (ICSRs) related to olaparib and niraparib. Descriptive statistics and disproportionality analysis were performed to compare the frequency and severity of reported ADRs. Results: Both olaparib and niraparib had common ADRs including nausea, vomiting, anemia, thrombocytopenia, and fatigue. However, olaparib was associated with a higher risk of myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), and interstitial lung disease, while niraparib had a higher incidence of gastrointestinal events and thrombocytopenia. Our analysis demonstrates that some specific ADRs, including peripheral neuropathy with niraparib, were reported at higher frequencies compared to clinical trials. The incidence of serious ADRs, including hospitalizations and life-threatening events, was higher with niraparib than with olaparib. Conclusions: This study highlights significant differences in the safety profiles of olaparib and niraparib, with implications for clinical decision-making. Continuous monitoring and personalized management of ADRs are essential to optimize patient outcomes.

Progesterone Enhances Sensitivity of Ovarian Cancer Cells to SN38 Through Inhibition of Topoisomerase I and Inducing Ferroptosis

BACKGROUND

Progesterone rapidly induces ovarian cancer cell death through non-genomic actions mediated by the membrane progesterone receptor (mPR).

AIMS

We investigated the combined effects of progesterone and SN38, an active metabolite of irinotecan, on ovarian cancer cells.

METHODS AND RESULTS

mPR-positive and PR-negative ovarian cancer cell lines were utilized in experiments. Tumor cells were exposed to SN38 or cisplatin for 48 h following exposure to progesterone for 30 min. The viable cell counts were measured using a colorimetric assay and the expression of topoisomerase I (TOPO-I), the direct target of SN38, was observed with or without exposure to progesterone. Moreover, we investigated the relationship between several types of programmed cell death and the SN38 sensitivity enhancement effect of progesterone using specific cell death inhibitors. The chemosensitivity to SN38 was 8.7- to 26.0-fold higher with the administration of progesterone than that without (p < 0.01), but not to cisplatin in ovarian cancer cells. Progesterone suppressed the expression of TOPO-I mRNA by less than 50% (p < 0.01). Furthermore, among various programmed cell death inhibitors, only the ferroptosis inhibitor attenuated the progesterone-induced SN38 chemosensitivity enhancement effect.

CONCLUSIONS

Progesterone increased sensitivity to SN38 by suppressing TOPO-I expression and inducing ferroptosis. The combination of progesterone and irinotecan could be a novel treatment modality for ovarian cancer.

IL17A/F secreted by ASCT2-overexpression ovarian cancer cells contributes to immune escape through the suppression of natural killer (NK) cells cytotoxicity by the activation of c-JUN/ PTGS2 pathway

Ovarian cancer (OC) is a deadly gynecologic cancer associated with metastasis, recurrence, and treatment resistance. The expression of the alanine-serine-cysteine transporter 2 (ASCT2) has been linked to poor prognosis and immune cell infiltration in OC tumors, but the underlying mechanisms are unclear. Lentiviral constructs were used to manipulate ASCT2 expression in OC cells (SKOV-3). The effects of ASCT2 on SKOV-3 behaviors including proliferation, invasion, migration, apoptosis, and cell cycle were assessed using various assays. The correlation between ASCT2 expression and immune infiltration in OC was analyzed using the Cancer Genome Atlas (TCGA) database. Co-culture experiments were conducted to evaluate the impact of ASCT2 overexpression in SKOV-3 on NK cells, followed by transcriptomics and cytokine analysis. ASCT2 expression and cytokine levels were characterized using qPCR and western blotting. ASCT2 overexpression significantly promoted cell proliferation, invasion, migration, and the percentage of G1-phase cells, while inhibiting apoptosis. ASCT2 silencing had the opposite effect. The expression of ASCT2 was negatively associated with NK cells in OC. ASCT2 overexpression in SKOV-3 cells led to excessive IL-17A/F production and inhibited the antitumor activity of NK cells, possibly through activating the IL-17 signaling pathway. The core regulatory genes c-JUN/PTGS2 in this pathway were upregulated, and antitumor cytokines were decreased in co-cultured NK cells, resulting in decreased antitumor activity and immune infiltration within the tumor. Our results suggest that overexpression of ASCT2 may play a predominant role in OC and NK cell immune infiltration within the tumor.

Predictive biomarkers for the efficacy of PARP inhibitors in ovarian cancer: an updated systematic review

BACKGROUND

PARP inhibitors are effective in treating ovarian cancer, especially for BRCA1/2 pathogenic variant carriers and those with HRD (homologous recombination deficiency). Concerns over toxicity and costs have led to the search for predictive biomarkers. We present an updated systematic review, expanding on a previous ESMO review on PARP inhibitor biomarkers.

METHODS

Following ESMO's 2020 review protocol, we extended our search to March 31, 2023, including PubMed and clinical trial data. We also reviewed the reference lists of review articles. We conducted a meta-analysis using a random-effects model to evaluate hazard ratios and assess the predictive potential of biomarkers and the effectiveness of PARP inhibitors in survival.

RESULTS

We found 375 articles, 103 of which were included after screening (62 primary research, 41 reviews). HRD remained the primary biomarker (95%), particularly BRCA1/2 variants (77%). In the non-HRD category, six articles (10%) introduced innovative biomarkers, including ADP-ribosylation, HOXA9 promoter methylation, patient-derived organoids, KELIM, and SLFN11.

DISCUSSION

Prospective assessment of real-time homologous recombination repair via nuclear RAD51 levels shows promise but needs validation. Emerging biomarkers like ADP-ribosylation, HOXA9 promoter methylation, patient-derived organoids, KELIM, and SLFN11 offer potential but require large-scale validation.

The impact of cytoreductive surgery on outcomes in high tumor burden ovarian cancer after induction of PARP inhibitors

OBJECTIVE

In advanced ovarian cancer, achieving R0 resection is a critical strategy for improving prognosis. However, even with R0 resection, the prognosis of patients with a high tumor burden remains poor. This study aimed to assess whether the introduction of poly(ADP-ribose) polymerase inhibitors (PARPi) has enhanced outcomes in such cases.

METHODS

We retrospectively analyzed patients with International Federation of Gynecology and Obstetrics (FIGO) stage III-IV ovarian cancer treated between January 2015 and December 2021. Patients were classified into Group A (pre-PARPi introduction) and Group B (post-PARPi introduction). Complete macroscopic resection was defined as R0. Progression-free survival (PFS), stratified by the Aletti Surgical Complexity Score (Aletti_SCS), was the primary endpoint and was evaluated using Cox regression models.

RESULTS

A total of 434 patients were included. In Group A, among those who achieved R0, the median PFS was 23.5 months for patients with high Aletti_SCS (95% confidence interval [CI]=14-30) and not reached for those with low Aletti_SCS (95% CI=30-not reached; adjusted hazard ratio [HR]=0.36, 95% CI=0.20-0.62). In Group B, the median PFS was not reached in both patients with high Aletti_SCS (95% CI=not reached-not reached) and low Aletti_SCS (95% CI=22-not reached; adjusted HR=4.98, 95% CI=1.14-21.78).

CONCLUSION

Following the introduction of PARPi, there was a trend toward improved PFS in patients with a higher Aletti_SCS who underwent R0 resection. These findings suggest that R0 resection may improve prognosis even in cases with a high tumor burden in the PARPi era.

Overview of systemic anticancer treatments: conventional cytotoxics

Cancer treatment is rapidly evolving and this review provides healthcare professionals who are not specialists in cancer therapeutics with a broad overview of the role of cancer systemic therapy, with a particular focus on chemotherapy.Historically, the majority of cytotoxic chemotherapy was used in patients with incurable or metastatic disease with the goal of disease control and symptom palliation. Now, with the advent of more effective, targeted systemic therapies (incorporating both cytotoxic and non-cytotoxic agents), systemic therapies are being used in more diverse treatment settings, both to increase the likelihood of cure and to induce prolonged disease remission.Chemotherapy (henceforth referring specifically to cytotoxic chemotherapy) remains important for the treatment of many cancer types. This article will review the principles of chemotherapy and the first-line systemic treatment paradigm of different cancer types. The potential toxicities of chemotherapy will also be described.

The Landscape of PARP Inhibitors in Solid Cancers

PARP inhibitors are a class of agents that have shown significant preclinical activity in models defective in homologous recombination (HR). The identification of synthetic lethality between HR defects and PARP inhibition led to several clinical trials in tumors with known HR defects (initially mutations in BRCA1/2 genes and subsequently in other genes involved in HR). These studies demonstrated significant responses in breast and ovarian cancers, which are known to have a significant proportion of patients with HR defects. Since the approval of the first PARP inhibitor (PARPi), olaparib, several other inhibitors have been developed, expanding the armamentarium available to clinicians in this setting. The positive results obtained in breast and ovarian cancer have expanded the use of PARPi in other solid tumors with HR defects, including prostate and pancreatic cancer in which these defects have been identified. The clinical trials have demonstrated responses to PARPi which are now also available for the subset of patients with prostate and pancreatic cancer with HR defects. This review summarizes the results obtained in solid tumors with PARPi and their potential use when combined with other agents, including immune checkpoint inhibitors that are likely to further increase the survival of these patients which still needs a dramatic improvement.

Breast cancer outcomes in women with ovarian cancer and a pathogenic germline BRCA mutation

BACKGROUND

Women with ovarian cancer (OC) and a pathogenic variant in the BRCA1 or BRCA2 genes are at increased risk of developing breast cancer (BC). Evidence for long term outcomes in these patients who undergo bilateral risk reduction mastectomy (RRM) after ovarian cancer is sparse. The aim of this study was to analyse the long-term breast cancer-related outcomes of patients who have been diagnosed with ovarian cancer and found to have BRCA1 or 2 pathogenic variants.

METHODS

Local approval was granted. The hospital clinical genetics database was interrogated to identify women who have been diagnosed with OC and a germline BRCA1/2 pathogenic variant between January 2010-March 2020. Patient demographics, OC treatment as well as any BC related information was analysed.

RESULTS

148 women were diagnosed with OC and a pathogenic variant in BRCA1/2 in the study period. 47 patients were excluded as they did not have treatment at our institution. 101 patients were included. The median age at diagnosis of OC was 52 years (IQR 46-61). Eighty-four (82 %) were FIGO stage 3 or 4 OC. At a median follow-up of 63 months (IQR 39-94), 55 (54.4 %) women had been diagnosed with a recurrence of ovarian cancer and 38 (37 %) women have died. Twenty-one (21 %) women were diagnosed with BC. 13 (12.9 %) had BC before OC, 4 after and 4 synchronous with OC. Of the remaining patients who did not have BC, 6 underwent bilateral risk reduction mastectomy (RRM) after treatment for OC.

DISCUSSION

Risk of disease recurrence and death due to stage 3 and 4 ovarian cancer remained high in this time period. RRM can be undertaken in carefully selected patients, however we would recommend reserving this for women who have favourable OC disease prognosis.

Real-world efficacy and toxicity of olaparib maintenance therapy in Korean ovarian cancer patients with an exploratory analysis of BRCA mutations

OBJECTIVE

To evaluate the real-world efficacy and toxicity of olaparib maintenance therapy in Korean patients with BRCA-mutated ovarian cancer (OC), with an exploratory analysis of BRCA mutations.

METHODS

We conducted a retrospective analysis of Korean BRCA-mutated OC patients treated with olaparib maintenance therapy as first-line (1Lm) or second-/subsequent-line (2Lm +) at Asan Medical Center, South Korea, from August 2015 to April 2023. Survival outcomes, including progression-free survival (PFS) and overall survival (OS), as well as toxicity, were analyzed with patient characteristics and BRCA mutations.

RESULTS

In 1Lm (n = 70), the 2-year PFS was 75.5 % and the 3-year OS was 98.5 %. In 2Lm + (n = 83), the 2-year PFS was 54.8 % and the 3-year OS was 87.3 %. The pathogenic p.Leu1780Pro BRCA1 mutation was a poor prognostic factor for PFS in 1Lm (hazard ratio [HR], 5.66). In 2Lm +, platinum-free interval ≥ 12 months was associated with better PFS (adjusted HR [aHR], 0.48) and OS (aHR, 0.31), whereas CA-125 ≥ 10 IU/mL at olaparib initiation was a poor prognostic factor (aHR, 2.12). A longer time interval between the last chemotherapy and maintenance therapy in 1Lm correlated with reduced hematologic toxicity ≥ grade 3 (odd ratio, 0.75) during maintenance therapy. Drug discontinuation due to toxicity occurred in 1.4 % of 1Lm and 6.0 % of 2Lm + .

CONCLUSIONS

Olaparib maintenance therapy was effective and tolerable in Korean BRCA-mutated OC patients, though the poor prognosis of the p.Leu1780Pro BRCA1 mutation in 1Lm warrants further investigation.

TPX2 serves as a novel target for expanding the utility of PARPi in pancreatic cancer through conferring synthetic lethality

BACKGROUND

PARP inhibitors (PARPi) have been licensed for the maintenance therapy of patients with metastatic pancreatic cancer carrying pathogenic germline BRCA1/2 mutations. However, mutations in BRCA1/2 are notably rare in pancreatic cancer.

OBJECTIVE

There is a significant unmet clinical need to broaden the utility of PARPi.

DESIGN

RNA sequencing was performed to screen potential targets for PARPi sensitivity. The synthetic lethal effects were verified in patient-derived xenograft (PDX), xenograft and patient-derived organoid models. Mechanisms were explored via LC‒MS/MS, coimmunoprecipitation, laser microirradiation, immunofluorescence, the homologous recombination (HR) or non-homologous end joining (NHEJ) reporter system, in situ proximity ligation assay and live-cell time-lapse imaging analyses.

RESULTS

Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is an exploitable vulnerability. TPX2 was downregulated in PDX models sensitive to PARPi, and TPX2 inhibition conferred synthetic lethality to PARPi both in vitro and in vivo. Mechanistically, TPX2 functions in a cell cycle-dependent manner. In the S/G2 phase, ATM-mediated TPX2 S634 phosphorylation promotes BRCA1 recruitment to double-strand breaks (DSBs) for HR repair, whereas non-phosphorylated TPX2 interacts with 53BP1 to recruit it for NHEJ. The balance between phosphorylated and non-phosphorylated TPX2 determines the DSB repair pathway choice. During mitosis, TPX2 phosphorylation enhances Aurora A activity, promoting mitotic progression and chromosomal stability. Targeting TPX2 S634 phosphorylation with a cell-penetrating peptide causes genomic instability and mitotic catastrophe and enhances PARPi sensitivity. Additionally, the inhibition of TPX2 or S634 phosphorylation combined with gemcitabine further sensitised pancreatic cancer to PARPi.

CONCLUSIONS

Our findings revealed the dual-functional significance of TPX2 in controlling DNA DSB repair pathway choice and mitotic progression, suggesting a potential therapeutic strategy involving PARPi for patients with pancreatic cancer.

First-line PARP inhibitor maintenance treatment in ovarian carcinoma for older adult women: a review of the current literature

Ovarian cancer (OC) is the leading cause of death in women with gynecological cancers. Its diagnosis is more likely in advanced ages, with the older population being the most seen in consultations. Poly(ADP-ribose) inhibitors (PARPi) have changed OC clinical practice and evolution, showing great benefit. However, there is a lack of evidence of PARPi in elderly population that can impact the therapeutic decision and the safety/efficacy. It is necessary to avoid age as limiting factor in PARPis prescription. We conducted a review of the most relevant randomized phase III trials of maintenance PARPi after first-line treatment of advanced OC. We observed the lack of a single criterion for considering older patients, varying among trials. There is a benefit of PARPis in different populations. However, PARPi effect on quality of life is not reported, something of great relevance considering their vulnerability. Measures are needed to benefit older patients to better adapt PARPi treatment.

Disease-free survival of 15 years after primary surgery in a patient with advanced high-grade serous ovarian cancer: a case report and literature review

Background

Ovarian cancer, particularly high-grade serous ovarian cancer (HGSOC), is the most lethal gynecological tumor, with most patients experiencing recurrence within 5 years. Long-term survival in HGSOC patients with advanced stages is exceedingly rare.

Case summary

We report a case of advanced HGSOC with exceptional long-term recurrence-free survival following initial treatment. In June 2009, the patient underwent suboptimal cytoreductive surgery for stage IIIC ovarian cancer, including total hysterectomy, bilateral salpingo-oophorectomy, omentectomy, appendectomy, and resection of mesenteric and peritoneal lesions. Postoperatively, residual lesions were observed in the mesenteries and para-aortic lymph nodes. Despite unfavorable prognostic factors (advanced stage, aggressive pathology, and incomplete resection), the patient showed remarkable chemosensitivity, remaining recurrence-free for 15 years.

Conclusion

The factors influencing long-term survival in HGSOC patients are not yet fully understood. We present this rare case to contribute data for further studies on long-term survival in advanced HGSOC.

Homologous recombination deficiency in ovarian cancer: Global expert consensus on testing and a comparison of companion diagnostics

BACKGROUND

Poly (ADP ribose) polymerase inhibitors (PARPis) are a treatment option for patients with advanced high-grade serous or endometrioid ovarian carcinoma (OC). Recent guidelines have clarified how homologous recombination deficiency (HRD) may influence treatment decision-making in this setting. As a result, numerous companion diagnostic assays (CDx) have been developed to identify HRD. However, the optimal HRD testing strategy is an area of debate. Moreover, recently published clinical and translational data may impact how HRD status may be used to identify patients likely to benefit from PARPi use. We aimed to extensively compare available HRD CDx and establish a worldwide expert consensus on HRD testing in primary and recurrent OC.

METHODS

A group of 99 global experts from 31 different countries was formed. Using a modified Delphi process, the experts aimed to establish consensus statements based on a systematic literature search and CDx information sought from investigators, companies and/or publications.

RESULTS

Technical information, including analytical and clinical validation, were obtained from 14 of 15 available HRD CDx (7 academic; 7 commercial). Consensus was reached on 36 statements encompassing the following topics: 1) the predictive impact of HRD status on PARPi use in primary and recurrent OC; 2) analytical and clinical validation requirements of HRD CDx; 3) resource-stratified HRD testing; and 4) how future CDx may include additional approaches to help address unmet testing needs.

CONCLUSION

This manuscript provides detailed information on currently available HRD CDx and up-to-date guidance from global experts on HRD testing in patients with primary and recurrent OC.

Implication of fibroblast growth factor 7 in ovarian cancer metastases and patient survival

Background/Objectives

Patients with ovarian cancer commonly experience metastases and recurrences, which contribute to high mortality. Our objective was to better understand ovarian cancer metastasis and identify candidate biomarkers and drug targets for predicting and preventing ovarian cancer recurrence.

Methods

Transcripts of 770 cancer-associated genes were compared in cells collected from ascitic fluid versus resected tumors of an ES-2 orthotopic ovarian cancer mouse model. Associated cell types and pathways were explored with bioinformatics. FGF7 protein was measured using capillary-based immunoassays or ELISA in mouse and clinical specimens. Significances of differential gene expression and patient prognosis were determined by volcano plot and log-rank test, respectively.

Results

Tumor transcriptomes exhibited higher endothelial cells, oxygenation, proteasome activity, and metabolism in comparison to ascites, but similar percentages of cancer-associated fibroblasts and immune cells. FGF7 mRNA was significantly higher in mouse tumors compared to ascites. FGF7 protein was significantly higher in tumors than in ascites in independent mouse models and clinical specimens. Serum FGF7 protein levels above the median of 25 patients with ovarian cancer were associated with worse progression-free and overall survival (p = 0.005 and 0.019, respectively) independent of patient and tumor characteristics.

Conclusions

In comparison to ascites, tumors exhibit different transcriptomic profiles that identify candidate biomarkers and drug targets for predicting and preventing recurrence. Among these, elevated tumoral FGF7 validated at the protein level and elevated serum FGF7 were significantly associated with worse patient survival. These results support further development of FGF7 receptor-targeted drugs and serum FGF7 to prevent and predict recurrence, respectively.

Exploiting somatic oncogenic driver alterations in a patient with Li-Fraumeni syndrome- paving the path towards precision medicine: a case report

BACKGROUND

Li-Fraumeni syndrome (LFS) is an autosomal dominant tumor predisposition syndrome characterized by a high familial incidence of various malignancies. It results from pathogenic/likely pathogenic heterozygous constitutional variants of the TP53 gene. Due to impaired DNA damage repair, conventional cytotoxic therapies or radiotherapy should be avoided whenever feasible to mitigate the high incidence of treatment-related secondary malignancies in these patients. However, there is limited evidence supporting the effectiveness of targeted therapy approaches in LFS patients.

CASE PRESENTATION

We present the case of a woman with breast cancer and subsequent osteosarcoma, both treated with surgery and chemotherapy. Constitutional genetic germline testing identified a pathogenic TP53 variant in line with the clinical features of Li-Fraumeni syndrome. Subsequent molecular analysis of the osteosarcoma tissue revealed homozygous loss of the CDKN2A gene locus, warranting treatment with CDK4/6 inhibitor palbociclib. Palbociclib therapy was discontinued after one year with no evidence of disease. One year later, ovarian cancer was diagnosed, with molecular analysis indicating interstitial heterozygous loss of the BRCA2 gene locus, providing a rationale for targeted therapy with the PARP inhibitor olaparib.

CONCLUSIONS

In the era of accessible and comprehensive genetic and phenotypic tumor profiling, this case study of a patient with Li-Fraumeni syndrome underscores the success of precision oncology in harnessing additional somatic oncogenic driver alterations. Furthermore, it emphasizes the indispensable role of an interdisciplinary molecular tumor board, enhancing the awareness of molecular profiling and targeted therapies in patients with rare cancer susceptibility disorders.

Cinobufagin modulates vasculogenic mimicry and tumor-associated macrophages to inhibit ovarian cancer progression

BACKGROUND

Ovarian cancer is among the most prevalent malignant tumors affecting women. While conventional therapies like surgery do provide some measure of disease control, they are accompanied by evident side effects that may readily result in drug resistance. Cinobufagin (HCS) is a water-soluble active component extracted from the dried skin of the Bufo gargarizans. Clinical studies have demonstrated its significant anti-tumor effects.

METHODS

Transcriptome sequencing identified Forkhead Box S1 (FOXS1)-related targets, and Western blot analysis evaluated the expression levels of vasculogenic mimicry (VM)-related proteins and pathway proteins after cinobufagin intervention. Immunofluorescence and ELISA were used to detect the effects of cinobufagin on M1 and M2 macrophage markers. Additionally, a co-culture model of Skov3 cells and macrophages was established to study the effects of cinobufagin on tumor-associated macrophage polarization.

RESULTS

Cinobufagin significantly inhibited the growth of Skov3 ovarian cancer cells both in vitro and in vivo. Additionally, cinobufagin decreased the expression levels of VM-related proteins, thereby affecting vasculogenesis both in vitro and in vivo. Transcriptomic analysis revealed that the regulation of the FOXS1 gene contributed to this inhibitory effect. In the co-culture system, we found that cinobufagin inhibited IL-4-induced M2 macrophage polarization. Overexpression of FOXS1 in Skov3 cells enhanced the activity of the C-C motif chemokine ligand 2/receptor 2 (CCL2/CCR2) pathway, which was suppressed by cinobufagin, thus affecting the tumor microenvironment.

CONCLUSION

Cinobufagin suppressed vasculogenic mimicry by regulating the FOXS1 gene and inhibited M2 macrophage polarization through the CCL2/CCR2 pathway, thereby affecting the tumor microenvironment.

Opportunities for predictive proteogenomic biomarkers of drug treatment sensitivity in epithelial ovarian cancer

Genomic analysis has played a significant role in the identification of driver mutations that are linked to disease progression and response to drug treatment in ovarian cancer. A prominent example is the stratification of epithelial ovarian cancer (EOC) patients with homologous recombination deficiency (HRD) characterized by mutations in DNA damage repair genes such as BRCA1/2 for treatment with PARP inhibitors. However, recent studies have shown that some epithelial ovarian tumors respond to PARP inhibitors irrespective of their HRD or BRCA mutation status. An exclusive focus on the genome overlooks the significant insight that can be gained from other biological analytes, including proteins, which carry out cellular functions. Proteogenomics is the integration of genomics, transcriptomics, epigenomics and proteomics data. This review paper provides novel insight into the role of proteogenomics as an analytical approach to identify predictive biomarkers of drug treatment response in epithelial ovarian cancer. Proteogenomic analysis can facilitate the identification of predictive biomarkers of drug treatment response, consequently greatly improving the stratification of patients with EOC for treatment towards a goal of personalized medicine.

Unraveling the complexity of HRD assessment in ovarian cancer by combining genomic and functional approaches: translational analyses of MITO16-MaNGO-OV-2 trial

BACKGROUND

Ovarian cancer (OvC) constitutes significant management challenges primarily due to its late-stage diagnosis and the development of resistance to chemotherapy. The standard treatment regimen typically includes carboplatin and paclitaxel, with the addition of poly (ADP-ribose) polymerase inhibitors for patients with high-grade serous ovarian cancer (HGSOC) harboring BRCA1/2 mutations. However, the variability in treatment responses suggests the need to investigate factors beyond BRCA1/2 mutations, such as DNA repair mechanisms and epigenetic alterations. Notably, homologous recombination repair deficiency (HRD) is observed in an additional 20% of HGSOC cases, indicating a broader spectrum of DNA repair defects. Existing commercial HRD assays have certain limitations, prompting a global effort to develop new genomic and functional tests through academic research.

MATERIALS AND METHODS

This study investigates, in the 187 high-grade serous and endometrioid tumors from the MITO16/MaNGO-OV-2 trial, academic HRD genomic tests in conjunction with a RAD51 immunofluorescence assay to assess functional activation of HRD. Additionally, the study incorporates analysis of microRNA-506 (miR-506) expression as a putative epigenetic effector.

RESULTS

The RAD51 test identified HRD in 73% of the samples and genomic HRD testing in 57%, with HRD identified in 45% of samples by both tests. The significant discrepancy between the two assays emphasizes the need to refine tumor classification for HRD. A three-group genomic classification unveiled superior progression-free survival (PFS) in high- and mild-HRD tumors compared with negative-HRD tumors. High concordance between RAD51 and genomic testing in high-HRD tumors suggests a subset of 'super-HRD' tumors exhibiting superior PFS. High expression of miR-506 may be used to further refine HRD status.

CONCLUSIONS

The study underscores the complexities of HRD assessment and advocates for a combined genomic and functional approach to enhance predictive accuracy in OvC treatment responses.

Schlafen 11 Expression in Patients With Small Cell Lung Cancer and Its Association With Clinical Outcomes

BACKGROUND

Schlafen 11 (SLFN-11) has been identified as a sensitizer of tumor cells to DNA-damaging agents. However, the relationship between SLFN-11 expression and clinical outcomes in patients with small cell lung cancer (SCLC) remains unexplored. Thus, we aimed to evaluate the impact of SLFN-11 expression on survival in patients with limited-stage (LS) SCLC.

METHODS

We conducted a retrospective review of data from patients pathologically diagnosed with LS-SCLC post-surgery between January 2008 and December 2018. SLFN-11 expression was assessed using immunohistochemistry in tissue microarrays and scored using a histology (H)-score (range: 0-300).

RESULTS

Overall, 86 patients were included in the analysis with a median H-score of 43 for SLFN-11 expression. Among the patients, 44 had high SLFN-11 expression (provisionally defined as H-score ≥ 43). No significant differences in clinical profiles were observed between the two groups (high and low SLFN expression). The median survival durations were not reached (NR; 95% confidence interval [CI]: 65.1 months to NR) and 33.5 months (95% CI: 24.2 months to NR) for patients with high and low SLFN-11 expression, respectively (hazard ratio [HR]: 0.40, 95% CI: 0.19-0.81; p = 0.012). Among patients who relapsed post-surgery (n = 21), the median survival durations were 22.0 (95% CI: 7.6-44.9 months) and 8.1 (95% CI: 1.8-24.6 months) months in patients with high and low SLFN-11 expression, respectively (HR: 0.22, 95% CI: 0.06-0.84; p = 0.026).

CONCLUSIONS

High SLFN-11 expression is associated with relatively longer survival in patients with LS-SCLC in both those undergoing surgery and those who have relapsed.

Collateral lethality: A unique type of synthetic lethality in cancers

Genetic interactions play crucial roles in cell-essential functions. Intrinsic genetic defects in tumors typically involve gain-of- and loss-of-function mutations in tumor suppressor genes (TSGs) and oncogenes, respectively, providing potential antitumor vulnerabilities. Moreover, tumor cells with TSG deficiencies exhibit heightened sensitivity to the inhibition of compensatory pathways. Synthetic and collateral lethality are two strategies used for exploiting novel drug targets in multiple types of cancer. Collateral lethality is a unique type of synthetic lethality that occurs when passenger genes are co-deleted in neighboring TSGs. Although synthetic lethality has already been successfully demonstrated in clinical practice, antitumor therapeutics based on collateral lethality are predominantly still in the preclinical phase. Therefore, screening for potential genetic interactions within the cancer genome has emerged as a promising approach for drug development. Here, the two conceptual therapeutic strategies that involve the deletion or inactivation of cancer-specific TSGs are discussed. Moreover, existing approaches for screening and identifying potential gene partners are also discussed. Particularly, this review highlights the current advances of "collateral lethality" in the preclinical phase and addresses the challenges involved in translating them into therapeutic applications. This review provides insights into these strategies as new opportunities for the development of personalized antitumor therapies.

Germline pathogenic variants among high hereditary risk patients with breast and ovarian cancer and unaffected subjects in Lebanese Arab women

BACKGROUND

The prevalence of germline pathogenic variants in high hereditary risk breast and/or ovarian cancer patients and unaffected subjects referred for testing is an unmet need in low and middle-income countries.

AIM

To determine the prevalence of germline pathogenic variants in high hereditary risk patients with breast and/or ovarian cancer and unaffected individuals.

METHODS

We retrospectively reviewed records of patients and unaffected subjects referred for germline pathogenic variant testing due to high hereditary risk between 2010-2020. Data was collected and analyzed on Excel sheet.

RESULTS

In total, 358 individuals were included, including 257 patients and 101 unaffected individuals with relatives with breast or ovarian cancer. The prevalence of breast cancer susceptibility gene (BRCA) 1/2 pathogenic variants was 8.63% (19/220) in patients with breast cancer, and 15.1% (5/33) in those with ovarian cancer. Among the 25 of 220 patients with breast cancer tested by next-generation sequencing, 3 patients had pathogenic variants other than BRCA1/2. The highest risk was observed in those aged 40 years with breast cancer and a positive family history, where the BRCA1/2 prevalence was 20.1% (9/43). Among the unaffected subjects, 31.1% (14/45) had the same BRCA1/2 pathogenic variants in their corresponding relatives. Among the subjects referred because of a positive family history of cancer without known hereditary factors, 5.35% (3/56) had pathogenic variants of BRCA1 and BRCA2. The c.131G>T nucleotide change was noted in one patient and two unrelated unaffected subjects with a BRCA1 pathogenic variant.

CONCLUSION

This study showed a 8.63% prevalence of pathogenic variants in patients with breast cancer and a 15.1% prevalence in patients with ovarian cancer. Among the relatives of patients with BRCA1/2 pathogenic variants, 31% tested positive for the same variant, while 5.3% of subjects who tested positive due to a family history of breast cancer had a BRCA pathogenic variant.

BRCA and Beyond: Impact on Therapeutic Choices Across Cancer

BACKGROUND

Identifying patients with gBRCAm is crucial to facilitate screening strategies, preventive measures and the usage of targeted therapeutics in their management. This review examines the evidence for the latest predictive and therapeutic approaches in BRCA-associated cancers.

CLINICAL DESCRIPTION

Data supports the use of adjuvant olaparib in patients with gBRCAm high-risk HER2-negative breast cancer. In advanced gBRCAm HER2-negative breast cancer, the PARPis talazoparib and olaparib have demonstrated benefit over standard chemotherapy. In ovarian cancer, olaparib, niraparib or rucaparib can be used as monotherapy in frontline maintenance. Olaparib and bevacizumab as a combination can also be used as frontline maintenance. In the relapsed platinum-sensitive setting, olaparib, niraparib and rucaparib are effective maintenance options in BRCAm patients who are PARPi naive. Both olaparib and rucaparib are effective options in BRCAm metastatic castrate-resistant prostate cancer (mCRPC). Evidence also exists for the benefit of PARPi combinations in mCRPC. In metastatic pancreatic cancer, olaparib can be used in gBRCAm patients who are responding to platinum chemotherapy. However, there may be a development of PARPi resistance. Understanding the pathophysiology that contributes to such resistance may allow the development of novel therapeutics. Combination therapy appears to have promising results in emerging trials. Seeking avenues for subsidised genetic testing can reduce the total costs of cancer management, leading to improve detection rates.

CONCLUSION

Identifying breast, ovarian, pancreatic and prostate cancer patients with gBRCAm plays a crucial predictive role in selecting those who will benefit significantly from PARPi therapy. The use of PARPi in gBRCAm HBOC-related cancers has resulted in significant survival benefits. Beyond BRCA1/2, HRR gene assessment and the consideration of other cancer predisposition syndromes may allow more patients to be eligible for and benefit from targeted therapies.

Molecular Subgroups of HRD Positive Ovarian Cancer and Their Prognostic Significance

Homologous recombination repair deficiency (HRD) is involved in the development of high-grade serous ovarian carcinoma (HGSOC) and its elevated sensitivity to platinum-based chemotherapy. To investigate the heterogeneity of the HRD-positive HGSOC we evaluated the HRD status, including BRCA mutations, genomic scar score, and methylation status of BRCA1/2 genes in 352 HGSOC specimens. We then divided the HRD-positive cohort into three molecular subgroups, the BRCA mutation cohort (BRCA+), BRCA1 methylation cohort (Meth+), and the rest of the HRD+ cohort (HRD+BRCA-Meth-), and evaluated their first-line chemotherapy response, benefit from olaparib, and progression-free survival (PFS). HRD-positive status was detected in 65% (228/352) of samples. The first group, BRCA+, accounted for 45% (102/228) of HRD positive cases and showed the best outcome in platinum therapy (ORR 96%), the highest olaparib benefit (p = 0.006) and the highest median PFS (46 months). The frequency of the second cohort, Meth+, among HRD-positive patients was 23% (52/228). Patients with Meth+ HGSOC showed a significantly poorer outcome, with a median PFS of 19 months, a significantly lower ORR to platinum therapy (84%) and a modest, but not significant, benefit from olaparib maintenance. The third HRD+BRCA-Meth- group accounted for 32% (74/228) of HRD-positive patients and showed an ORR to platinum therapy similar to that of the BRCA+ group (90%), a higher, but not statistically significant, benefit from olaparib and a median PFS of 23 months. In conclusion, Meth+ subgroup had poor outcomes in terms of chemotherapy response, olaparib benefit, and PFS compared to the other HRD+ subgroups, requiring a more thorough follow-up.

Patterns of genomic instability in > 2000 patients with ovarian cancer across six clinical trials evaluating olaparib

BACKGROUND

The introduction of poly(ADP-ribose) polymerase (PARP) inhibitors represented a paradigm shift in the treatment of ovarian cancer. Genomic data from patients with high-grade ovarian cancer in six phase II/III trials involving the PARP inhibitor olaparib were analyzed to better understand patterns and potential causes of genomic instability.

PATIENTS AND METHODS

Homologous recombination deficiency (HRD) was assessed in 2147 tumor samples from SOLO1, PAOLA-1, Study 19, SOLO2, OPINION, and LIGHT using next-generation sequencing technology. Genomic instability scores (GIS) were assessed in BRCA1 and/or BRCA2 (BRCA)-mutated (BRCAm), non-BRCA homologous recombination repair-mutated (non-BRCA HRRm), and non-HRRm tumors.

RESULTS

BRCAm was identified in 1021/2147 (47.6%) tumors. BRCAm tumors had significantly higher GIS than non-BRCAm tumors (P < 0.001) and high biallelic loss (815/838; 97.3%) regardless of germline (658/672; 97.9%) or somatic (101/108; 93.5%) BRCAm status. In non-BRCA HRRm tumors (n = 121) a similar proportion were HRD-positive (GIS ≥ 42: 55/121; 45.5%) relative to HRD-negative (GIS < 42: 52/121; 43.0%). GIS was highly variable in non-BRCA HRRm (median 42 [interquartile range (IQR) 29-58]) and non-HRRm (n = 1005; median 32 [IQR 20-55]) tumors. Gene mutations with high GIS included HRR genes BRIP1 (median 46 [IQR 41-58]), RAD51C (median 58 [IQR 48-66]), RAD51D (median 62 [IQR 54-69]), and PALB2 (median 64 [IQR 58-74]), and non-HRR genes NF1 (median 49 [IQR 25-60]) and RB1 (median 55 [IQR 30-71]). CCNE1-amplified and PIK3CA-mutated tumors had low GIS (CCNE1-amplified: median 24 [IQR 18-29]; PIK3CA-mutated: median 32 [IQR 14-52]) and were predominantly non-BRCAm.

CONCLUSIONS

These analyses provide valuable insight into patterns of genomic instability and potential drivers of HRD, besides BRCAm, in ovarian cancer and will help guide future research into the potential clinical effectiveness of anti-cancer treatments in ovarian cancer, including PARP inhibitors as well as other precision oncology agents.

TRIAL REGISTRATION

The SOLO1 trial was registered at ClinicalTrials.gov (NCT01844986) on April 30, 2013; the PAOLA-1 trial was registered at ClinicalTrials.gov (NCT02477644) on June 18, 2015 (retrospectively registered); Study 19 was registered at ClinicalTrials.gov (NCT00753545) on September 12, 2008 (retrospectively registered); the SOLO2 trial was registered at ClinicalTrials.gov (NCT01874353) on June 7, 2013; the OPINION trial was registered at ClinicalTrials.gov (NCT03402841) on January 3, 2018; the LIGHT trial was registered at ClinicalTrials.gov (NCT02983799) on November 4, 2016.

Prevalence and outcomes of germline pathogenic variants of homologous recombination repair genes in ovarian cancer

Germline pathogenic variants (PVs) are pivotal in gynecological oncology. We focused on the prevalence, clinicopathological features, and survival impact of homologous recombination repair (HRR) PVs in patients with epithelial ovarian cancer (EOC). This was a multicenter retrospective cohort study, and 1248 patients with EOC were registered. Eligible patients (n = 1112) underwent germline DNA analysis for 26 cancer predisposition genes, including nine HRR-related genes, such as BRCA1/2, BRIP1, PALB2, RAD51C/D, and ATM. The associations between clinicopathological factors and HRR-related PVs were examined. Kaplan-Meier and Cox regression analyses were conducted. Among 1091 analyzed patients, 153 (14.0%) carried PVs and 140 (12.8%) were HRR-related. HRR-PV-positive status significantly correlated with serous carcinoma (22.9% vs. 4.8%, P < 0.0001) and advanced disease (18.5% vs. 5.9%, P < 0.0001). The HRR-PV-positive group exhibited higher prevalence of personal breast (12.9%) and familial breast/ovarian (29.2%) cancer history. HRR status independently improved overall survival in stage III/IV disease (P = 0.04) but not progression-free survival. HRR-related germline PVs exhibit distinct clinicopathological features with survival implications. Variants were significantly associated with serous carcinoma and advanced disease, underscoring the importance of genetic testing to develop individualized EOC treatment strategies. Considering the study period (2000-2019), the limited use of bevacizumab and poly (ADP-ribose) polymerase inhibitors as maintenance therapy should be recognized.

Mathematical modeling framework enhances clinical trial design for maintenance treatment in oncology

Clinical trials are costly and time-intensive endeavors, with a high rate of drug candidate failures. Moreover, the standard approaches often evaluate drugs under a limited number of protocols. In oncology, where multiple treatment protocols can yield divergent outcomes, addressing this issue is crucial. Here, we present a computational framework that simulates clinical trials through a combination of mathematical and statistical models. This approach offers a means to explore diverse treatment protocols efficiently and identify optimal strategies for oncological drug administration. We developed a computational framework with a stochastic mathematical model as its core, capable of simulating virtual clinical trials closely recapitulating the clinical scenarios. Testing our framework on the landmark SOLO-1 clinical trial investigating Poly-ADP-Ribose Polymerase maintenance treatment in high-grade serous ovarian cancer, we demonstrate that managing toxicity through treatment interruptions or dose reductions does not compromise treatment's clinical benefits. Additionally, we provide evidence suggesting that further reduction of hematological toxicity could significantly improve the clinical outcomes. The value of this computational framework lies in its ability to expedite the exploration of new treatment protocols, delivering critical insights pivotal to shaping the landscape of upcoming clinical trials.

Brain Metastases in Gynaecologic Cancer: A Retrospective Cohort Study Evaluating Treatment Outcomes, Prognostic Factors, and Overall Survival

(1) Background: The objectives of this study were to assess survival of patients with a diagnosis of brain metastases secondary to gynaecologic malignancy and the impact of clinicopathological factors on prognosis in this population. (2) Methods: A retrospective cohort of patients with gynaecologic cancers diagnosed with brain metastases treated with radiation at a tertiary care centre from 1 January 2004 until 30 September 2023 was studied. Kaplan-Meier method and log-rank test were used to evaluate survival, and cox regression was used to identify significant predictive factors of survival. (3) Results: In total, 103 patients were included in this study. Median age at diagnosis of brain metastases was 59 (range 30-94). Median survival time following diagnosis of brain metastases was 3.6 months (range 0.4-183.8). Survival was significantly longer for patients treated with surgery combined with radiation compared to radiation alone and with stereotactic radiosurgery (SRS) compared to whole brain radiation therapy (WBRT). Cox regression revealed that primary ovarian malignancy, extracranial disease at diagnosis, and ≥3 brain metastases were associated with poorer prognosis, and complete response to prior treatment was associated with more favourable prognosis. (4) Conclusions: Data from this study will assist in providing evidence-based prognostic information to patients with gynaecologic malignancy diagnosed with brain metastases.

Dual Targeting of CX3CR1 and PARP in Models of High-Grade Serous Ovarian Carcinoma

BACKGROUND/OBJECTIVES

Clinical use of poly(ADP-ribose) polymerase inhibitors (PARPis) against metastatic high-grade serous ovarian carcinoma (HGSOC) is limited to cases with deficient a homologous recombination (HR). Our objective was to determine whether the impairment of the fractalkine receptor (CX3CR1) could sensitize HR-proficient cases to PARPis.

METHODS

The efficacy of a dual drug combination, including AZD8797, an inhibitor of CX3CR1, and several PARPis was examined using cell lines and xenograft models.

RESULTS

The effectiveness of PARPis and AZD8797 drug combinations ranged from additive to strongly synergistic. Olaparib was synergistic with AZD8797 in OVCAR-4, Caov-3, and OHSAHO. Niraparib and AZD8797 produced synergy in OVCAR-4 and ES2. Rucaparib and AZD8797 were strongly synergistic in Caov-3 and OVSAHO. Veliparib was strongly synergistic with AZD8797 in OVCAR-4 and Caov-3. Notably, a combination of veliparib and AZD8797 produced a strong synergistic effect in a xenograft model.

CONCLUSIONS

While the exact mechanisms determining the nature of the PARPis and AZD8797 interaction remain to be uncovered, our data indicate that, in a subset of models, selected PARPis strongly synergize with the inhibition of CX3CR1, suggesting a potential therapeutic opportunity.

Polθ: emerging synthetic lethal partner in homologous recombination-deficient tumors

The most remarkable finding in synthetic lethality (SL) is the hypersensitivity to PARP inhibitors (PARPis) of the tumors harboring defects in genes involved in homologous repair (HR) such as BRCA1/2. Despite initial responsiveness to PARPi, the penetrance of the synthetic lethal interactions between BRCA1/2 genes and PARPi is incomplete. Thus, a significant proportion of HR-defective tumors experience intrinsic or acquired resistance, representing a key challenge of clinical research. An expanded concept of SL is opening new ways and includes novel forms of genetic interactions, investigating not only traditional SL of pairs genes but also SL between biological pathways that regulate the same essential survival cell function. In this context, recent research showed that HR and theta-mediated end-joining (TMEJ) pathways exhibit SL. DNA polymerase theta (Polθ) is encoded by the POLQ gene and is a key component of the TMEJ, an essential backup pathway, intrinsically mutagenic, to repair resected double-strand breaks (DSBs) when the non-homologous end joining (NHEJ) and HR are impaired. Polθ is broadly expressed in normal tissues, overexpressed in several cancers, and typically associated with poor outcomes and shorter relapse-free survival. Notably, HR-deficient tumor cells present the characteristic mutational signatures of the error-prone TMEJ pathway. According to this observation, the loss of HR proteins, such as BRCA1 or BRCA2, contributes to increasing the TMEJ-specific genomic profile, suggesting synthetic lethal interactions between loss of the POLQ and HR genes, and resulting in the emerging interest for Polθ as a potential therapeutic target in BRCA1/2-associated tumors.This review summarizes the converging roles of the POLQ and HR genes in DNA DSB repair, the early-stage clinical trials using Polθ inhibitor to treat HR-defective tumors and to overcome BRCA-reversion mutations responsible for therapeutic resistance, and the novel pleiotropic effects of Polθ, paving the way for the development of unexplored synthetic lethality strategies.

Emerging strategies to overcome PARP inhibitors' resistance in ovarian cancer

The utilization of PARP inhibitors (PARPis) has significantly improved the prognosis for ovarian cancer patients. However, as the use of PARPis increases, the issue of PARPi resistance has become more prominent. Prolonged usage of PARPis can lead to the development of resistance in ovarian cancer, often mediated by mechanisms such as homologous recombination (HR) recovery, ultimately resulting in cancer relapse. Overcoming PARPi resistance in ovarian cancer is a pressing concern, aiming to enhance the clinical benefits of PARPi treatment and delay disease recurrence. Here, we summarize the mechanisms underlying PARPi resistance, methods for analyzing resistance, and strategies for overcoming it. Our goal is to inspire the development of more cost-effective and convenient methods for analyzing resistance mechanisms, as well as safer and more effective strategies to overcome resistance. These advancements can contribute to developing personalized approaches for treating ovarian cancer.

Niraparib plays synergistic antitumor effects with NRT in a mouse ovarian cancer model with HRP

OBJECTIVE

PARPi offers less clinical benefit for HRP patients compared to HRD patients. PARPi has an immunomodulatory function. NRT therapy targets tumor neoantigens without off-target immune toxicity. We explored the synergy between Niraparib and NRT in enhancing antitumor activity in an HRP ovarian cancer mouse model.

METHODS

In the C57BL/6 mouse ID8 ovarian cancer model, the effect of Niraparib on reshaping TIME was evaluated by immune cell infiltration analysis of transcriptomic data. The antitumor effects of Niraparib, NRT, and their combined use were systematically evaluated. To corroborate alterations in TILs, TAMs, and chemokine profiles within the TIME, we employed immunofluorescence imaging and transcriptome sequencing analysis.

RESULTS

Niraparib increased the M1-TAMs and activated CD8+ T cells in tumor tissues of C57BL/6 mice with ID8 ovarian cancer. GSEA showed that gene set associated with immature DC and INFα, cytokines and chemokines were significantly enriched in immune feature, KEGG and GO gene sets, meanwhile CCL5, CXCL9 and CXCL10 play dominant roles together. In the animal trials, combined group had a tumor growth delay compared with Niraparib group (P < 0.01) and control group (P < 0.001), and longer survival compared with the single agent group (P<0.01) .

CONCLUSIONS

Niraparib could exert immune-reshaping effects, then acts synergistic antitumor effects with NRT in HRP ovarian cancer model. Our findings provide new ideas and rationale for combined immunotherapy in HRP ovarian cancer.

CYP1B1 promotes PARPi-resistance via histone H1.4 interaction and increased chromatin accessibility in ovarian cancer

INTRODUCTION

Ovarian cancer is the most lethal gynecological cancer and presents significant therapeutic challenges. The discovery of synthetic lethality between PARP inhibitors (PARPi) and homologous recombination deficiency marked a new era in treating BRCA1/2-mutated tumors. However, PARPi resistance remains a major clinical challenge.

METHODS

RNA sequencing was used to identify genes altered by PARPi treatment and LC-MS was used to detect proteins interacting with CYP1B1. Resistance mechanisms were explored through ATAC-seq and gene expression manipulation. Additional techniques, including micrococcal nuclease digestion assays, DAPI staining, and fluorescence microscopy, were used to assess changes in nuclear morphology and chromatin accessibility.

RESULTS

The gradual exposure of Olaparib has developed a PARPi-resistant cell line, A2780-OlaR, which exhibits significant upregulation of CYP1B1 at both RNA and protein levels. Down-regulating CYP1B1 expression or using specific inhibitors decreased the cellular response to Olaparib. Linker histone H1.4 was identified as associated with CYP1B1. ATAC-seq showed differential chromatin accessibility between A2780-OlaR and parental cells, indicating that the downregulation of H1.4 was associated with increased chromatin accessibility and higher cell viability after Olaparib treatment.

CONCLUSION

Our findings reveal a novel role for CYP1B1 in driving PARPi resistance through distinct molecular mechanisms in A2780-OlaR. This study highlights the importance of chromatin accessibility in PARPi efficacy and suggests the CYP1B1/H1.4 axis as a promising therapeutic target for overcoming drug resistance in ovarian cancer, offering potentially therapeutic benefits.

Long-term outcomes of PARP inhibitors in ovarian cancer: survival, adverse events, and post-progression insights

Poly-ADP-ribose polymerase inhibitors (PARPis) have revolutionized the management of BRCA-mutated (BRCAmut) and homologous recombination deficiency (HRD)-positive ovarian cancer (OC). While long-term analyses clearly support the use of PARPi as maintenance therapy after first-line chemotherapy, recent data have raised concerns on detrimental overall survival (OS) in non-BRCAmut OC, a greater incidence of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), and unfavorable outcomes following subsequent platinum-based chemotherapy in pretreated OC patients. In this report we discuss the long-term follow-up results from phase III trials in pretreated OC patients, which led to the Food and Drug Administration's withdrawal of PARPi indications in this setting. We summarize the newly available evidence concerning the risk of MDS/AML and the post-progression efficacy results after PARPi. We emphasize the importance of long-term follow-up and real-world data coming from international registries to define the efficacy and safety of stopping PARPi at relapse at a pre-specified time. To this point, biomarkers able to identify the patients who will experience long-term remission with PARPi maintenance or develop early resistance are urgently needed to guide treatment decision and duration.

Sodium bicarbonate potentiates the antitumor effects of Olaparib in ovarian cancer via cGMP/PKG-mediated ROS scavenging and M1 macrophage transformation

The high metabolic requirements of cancer cells result in excess accumulation of H+ in the tumor microenvironment. Therefore, the extracellular pH of solid tumors is acidic, whereas the pH of normal tissues is more alkaline. The acidic tumor environment is correlated with tumor metastasis, immune escape, and chemoresistance, but the underlying mechanisms remain elusive. Herein, we demonstrate that sodium bicarbonate, a weakly alkaline compound, induces cytotoxicity in ovarian cancer cells and hinders cancer migration and invasion in vitro. The anti-cancer efficacy of Olaparib can be significantly augmented when combined with sodium bicarbonate. In vivo experiments suggest that the combinatorial treatment of sodium bicarbonate and Olaparib is biocompatible and more effective at inhibiting ovarian cancer growth than either treatment alone. Additionally, RNA-sequencing results reveal that the differentially expressed genes are enriched in pathways related to reactive oxygen species (ROS) generation, such as the cGMP/PKG pathway. The combined treatment increases M1 macrophage composition in tumors and reduces the accumulation of excessive ROS. These findings strongly suggest that sodium bicarbonate holds great potential as an adjuvant treatment by scavenging ROS accumulation and promoting M1 macrophage composition, thereby enhancing Olaparib's anti-cancer activity.