Combined PARP and Immune Checkpoint Inhibition in Ovarian Cancer

A Comprehensive Analysis Exploring the Impact of an Immunogenic Cell Death-Related Panel for Ovarian Cancer

Ovarian cancer (OV) is a malignant tumor that ranks first among gynecological cancers, thus posing a significant threat to women's health. Immunogenic cell death (ICD) can regulate cell death by activating the adaptive immune system. Here, we aimed to comprehensively characterize the features of ICD-associated genes in ovarian cancer, and to investigate their prognostic value and role in the response to immunotherapy. After analyzing datasets from The Cancer Genome Atlas, we utilized weighted gene coexpression network analysis to screen for hub genes strongly correlated with ICD genes in OV, which was subsequently validated with OV samples from the Gene Expression Omnibus (GEO) database. A prognostic risk model was then constructed after combining univariate, multivariate Cox regression and LASSO regression analysis to recognize nine ICD-associated molecules. Next, we stratified all OV patients into two subgroups according to the median value. The multivariate Cox regression analysis showed that the risk model could predict OV patient survival with good accuracy. The same results were also found in the validation set from GEO. We then compared the degree of immune cell infiltration in the tumor microenvironment between the two subgroups of OV patients, and revealed that the high-risk subtype had a higher degree of immune infiltration than the low-risk subtype. Additionally, in contrast to patients in the high-risk subgroup, those in the low-risk subgroup were more susceptible to chemotherapy. In conclusion, our research offers an independent and validated model concerning ICD-related molecules to estimate the prognosis, degree of immune infiltration, and chemotherapy susceptibility in patients with OV.

Development of a nano-vaccine for high-grade serous ovarian cancer

High-Grade Serous Carcinoma (HGSC) is characterised by aggressive malignant tumours and poor prognosis accounting for 75% of ovarian cancer. Conventional treatments often result in relapse, with a need for innovative therapeutic approaches. This study aimed to develop and evaluate a DNA vaccine targeting the preferentially expressed antigen of melanoma, PRAME, a cancer tumour antigen (CTA) overexpressed in HGSC. PRAME demonstrated the highest differential gene expression between normal fallopian tubes and HGSC tumour tissues in a range of patient datasets. The PRAME DNA was condensed by the cationic cell-penetrating peptide RALA to form nanoparticles (NPs). These self-assembling NPs exhibited a mean hydrodynamic size <150 nm and zeta potential >10 mV at N : P ratios ≥4 with ≤3% free DNA. The NPs successfully transfected NCTC-929 and DC 2.4 cells with PRAME overexpression, with negligible cytotoxicity. Vaccination with the NPs in vivo elevated CD4+ and CD8+ T-cell activation with increased expression of INF-γ and IL-2 cytokines. Vaccination also significantly improved survival rates in a PRAME-expressing tumour model in vivo. This study demonstrated the utility of a PRAME-targeted DNA vaccine for HGSC treatment which warrants further investigation.

Mitigating T cell DNA damage during PARP inhibitor treatment enhances antitumor efficacy

Poly(ADP-ribose) polymerase inhibitors (PARPis) are a class of agents targeting DNA damage repair that have become standard therapy for epithelial ovarian cancer (EOC) and multiple other solid tumors. In addition to targeting DNA damage repair, PARPis actively modulate antitumor immune responses, with efficacy being partially dependent on T cell activity. Here, we found that patient T cells sustain DNA damage during PARPi treatment, which reduces treatment efficacy. Leveraging paired pre- and posttreatment tumor samples from a clinical trial of patients with EOC treated with neoadjuvant niraparib as monotherapy, we showed that the PARPi caused DNA damage, slowed proliferation, and increased apoptosis in T cells, which we validated both in vitro and in mouse models. A genome-wide CRISPR (clustered regularly interspaced short palindromic repeats) knockout screen in primary human T cells identified PARP1 as the principal mediator of PARPi-induced T cell death. T cell-specific deletion of PARP1 or mutating Parp1 at its binding sites in transgenic mice led to reduced T cell DNA damage during PARPi treatment, resulting in improved efficacy of PARPis, alone or in combination with immune checkpoint inhibition. We then engineered PARPi-tolerant CAR T cells using cytosine base editing, which decreased PARPi-induced PARP1 trapping and led to reduced PARPi-induced DNA damage, resulting in superior antitumor efficacy in xenograft models compared with parental CAR T cells. This study highlights the relevance of PARPi-induced DNA damage to T cells and suggests opportunities to improve the efficacy of PARPis as monotherapy or in combination with immunotherapy.

The Potential of PARP Inhibitors as Antitumor Drugs and the Perspective of Molecular Design

PARP (poly-ADP ribose polymerase) has received widespread attention in cancer treatment. Research has shown that PARP plays a crucial role in DNA damage repair and has become a popular target for drug design. Based on the mechanism of "synthetic lethality", multiple PARPis (PARP inhibitors) have been launched for the treatment of BRCA deficient tumors. For example, the approved PARPis have shown significant potential in cancer treatment, particularly in breast cancer and cancers associated with BRCA1/BRCA2 deficiencies. However, the clinical efficacy and safety of PARP inhibitors in different cancers remain issues that cannot be overlooked. The design of PARPis aims to eliminate their resistance and broaden their application scope. Designing selective PARP-1 inhibitors is also a potential strategy. PROTACs (Proteolysis Targeting Chimeras) to degrade PARP have become a potential novel cancer treatment strategy.

Myc-mediated inhibition of HIF1a degradation promotes M2 macrophage polarization and impairs CD8 T cell function through lactic acid secretion in ovarian cancer

Ovarian cancer, the eleventh most prevalent cancer among women and a significant cause of cancer-related mortality, poses considerable challenges. While the Myc oncogene is implicated in diverse cancers, its impact on tumours expressing Myc during immune therapy processes remains enigmatic. Our study investigated Myc overexpression in a murine ovarian cancer cell line, focusing on alterations in HIF1a function. Seahorse experiments were utilized to validate metabolic shifts post-Myc overexpression. Moreover, we explored macrophage polarization and immunosuppressive potential following coculture with Myc-overexpressing tumour cells by employing Gpr132-/- mice to obtain mechanistic insights. In vivo experiments established an immune-competent tumour-bearing mouse model, and CD8 T cell, Treg, and macrophage infiltration post-Myc overexpression were evaluated via flow cytometry. Additionally, adoptive transfer of OTI CD8 T cells was conducted to investigate antigen-specific immune response variations after Myc overexpression. The findings revealed a noteworthy delay in HIF1a degradation, enhancing its functionality and promoting the classical Warburg effect upon Myc overexpression. Lactic acid secretion by Myc-overexpressing tumour cells promoted Gpr132-dependent M2 macrophage polarization, leading to the induction of macrophages capable of significantly suppressing CD8 T cell function. Remarkably, heightened macrophage infiltration in tumour microenvironments post-Myc overexpression was observed alongside impaired CD8 T cell infiltration and function. Interestingly, CD4 T-cell infiltration remained unaltered, and immune-suppressive effects were alleviated when Myc-overexpressing tumour cells were administered to Gpr132-/- mice, shedding light on potential therapeutic avenues for ovarian cancer management.

Unlocking the potential of immunotherapy in platinum-resistant ovarian cancer: rationale, challenges, and novel strategies

Ovarian cancer is a significant global health challenge, with cytoreductive surgery and platinum-based chemotherapy serving as established primary treatments. Unfortunately, most patients relapse and ultimately become platinum-resistant, at which point there are limited effective treatment options. Given the success of immunotherapy in inducing durable treatment responses in several other cancers, its potential in platinum-resistant ovarian cancer (PROC) is currently being investigated. However, in unselected advanced ovarian cancer populations, researchers have reported low response rates to immune checkpoint inhibition, and thus far, no validated biomarkers are predictive of response. Understanding the intricate interplay between platinum resistance, immune recognition, and the tumour microenvironment (TME) is crucial. In this review, we examine the research challenges encountered thus far, the biological rationale for immunotherapy, the underlying mechanisms of immune resistance, and new strategies to overcome resistance.

Advanced endometrial cancer-The next generation of treatment: A society of gynecologic oncology journal club clinical commentary

In February of 2024, the Society of Gynecologic Oncology (SGO) hosted a journal club focused on new treatment options for the management of advanced and metastatic endometrial cancer. This clinical commentary is intended to provide a summary report of that presentation. The session described the importance of molecular characterization shown in the work of The Cancer Genome Atlas (TCGA). The updated 2023 FIGO staging of endometrial cancer was reviewed. The panel then described the role of upfront immunotherapy for the treatment of advanced or recurrent endometrial cancer as demonstrated in four recent trials (RUBY, NRG-GY018, AtTEnd, and DUO-E studies). The DUO-E study uniquely examined the combination immunotherapy with a PARP inhibitor. The trials had unique differences in inclusion criteria, primary outcomes, and length of maintenance therapy, but all boasted similarly promising results particularly in mismatch repair deficient (dMMR) endometrial cancer. This era of rapid innovation in advanced and recurrent endometrial cancer will hopefully enhance individualized treatment approaches and improved outcomes for patients with endometrial cancer.

Strategies to enhance the therapeutic efficacy of anti-PD-1 antibody, anti-PD-L1 antibody and anti-CTLA-4 antibody in cancer therapy

Although immune checkpoint inhibitors (anti-PD-1 antibody, anti-PD-L1 antibody, and anti-CTLA-4 antibody) have displayed considerable success in the treatment of malignant tumors, the therapeutic effect is still unsatisfactory for a portion of patients. Therefore, it is imperative to develop strategies to enhance the effect of these ICIs. Increasing evidence strongly suggests that the key to this issue is to transform the tumor immune microenvironment from a state of no or low immune infiltration to a state of high immune infiltration and enhance the tumor cell-killing effect of T cells. Therefore, some combination strategies have been proposed and this review appraise a summary of 39 strategies aiming at enhancing the effectiveness of ICIs, which comprise combining 10 clinical approaches and 29 foundational research strategies. Moreover, this review improves the comprehensive understanding of combination therapy with ICIs and inspires novel ideas for tumor immunotherapy.

Beyond monotherapy: An era ushering in combinations of PARP inhibitors with immune checkpoint inhibitors for solid tumors

The introduction of PARP inhibitors (PARPis) and immune checkpoint inhibitors (ICIs) has marked a significant shift in the treatment landscape for solid tumors. Emerging preclinical evidence and initial clinical trials have indicated that the synergistic application of PARPis and ICIs may enhance treatment efficacy and potentially improve long-term patient outcomes. Nonetheless, how to identify specific tumor types and molecular subgroups most likely to benefit from this combination remains an area of ongoing research. This review thoroughly examines current studies on the co-administration of PARPis and ICIs across various solid tumors. It explores the underlying mechanisms of action, evaluates clinical efficacy, identifies potential responder populations, and delineates common adverse events alongside strategic management approaches. The aim is to offer a detailed understanding of this combination therapy, potentially guiding future therapeutic strategies for solid tumors.

Targeting ATR Pathway in Solid Tumors: Evidence of Improving Therapeutic Outcomes

The DNA damage response (DDR) system is a complicated network of signaling pathways that detects and repairs DNA damage or induces apoptosis. Critical regulators of the DDR network include the DNA damage kinases ataxia telangiectasia mutated Rad3-related kinase (ATR) and ataxia-telangiectasia mutated (ATM). The ATR pathway coordinates processes such as replication stress response, stabilization of replication forks, cell cycle arrest, and DNA repair. ATR inhibition disrupts these functions, causing a reduction of DNA repair, accumulation of DNA damage, replication fork collapse, inappropriate mitotic entry, and mitotic catastrophe. Recent data have shown that the inhibition of ATR can lead to synthetic lethality in ATM-deficient malignancies. In addition, ATR inhibition plays a significant role in the activation of the immune system by increasing the tumor mutational burden and neoantigen load as well as by triggering the accumulation of cytosolic DNA and subsequently inducing the cGAS-STING pathway and the type I IFN response. Taken together, we review stimulating data showing that ATR kinase inhibition can alter the DDR network, the immune system, and their interplay and, therefore, potentially provide a novel strategy to improve the efficacy of antitumor therapy, using ATR inhibitors as monotherapy or in combination with genotoxic drugs and/or immunomodulators.

Durvalumab Plus Carboplatin/Paclitaxel Followed by Maintenance Durvalumab With or Without Olaparib as First-Line Treatment for Advanced Endometrial Cancer: The Phase III DUO-E Trial

PURPOSE

Immunotherapy and chemotherapy combinations have shown activity in endometrial cancer, with greater benefit in mismatch repair (MMR)-deficient (dMMR) than MMR-proficient (pMMR) disease. Adding a poly(ADP-ribose) polymerase inhibitor may improve outcomes, especially in pMMR disease.

METHODS

This phase III, global, double-blind, placebo-controlled trial randomly assigned eligible patients with newly diagnosed advanced or recurrent endometrial cancer 1:1:1 to: carboplatin/paclitaxel plus durvalumab placebo followed by placebo maintenance (control arm); carboplatin/paclitaxel plus durvalumab followed by maintenance durvalumab plus olaparib placebo (durvalumab arm); or carboplatin/paclitaxel plus durvalumab followed by maintenance durvalumab plus olaparib (durvalumab + olaparib arm). The primary end points were progression-free survival (PFS) in the durvalumab arm versus control and the durvalumab + olaparib arm versus control.

RESULTS

Seven hundred eighteen patients were randomly assigned. In the intention-to-treat population, statistically significant PFS benefit was observed in the durvalumab (hazard ratio [HR], 0.71 [95% CI, 0.57 to 0.89]; P = .003) and durvalumab + olaparib arms (HR, 0.55 [95% CI, 0.43 to 0.69]; P < .0001) versus control. Prespecified, exploratory subgroup analyses showed PFS benefit in dMMR (HR [durvalumab v control], 0.42 [95% CI, 0.22 to 0.80]; HR [durvalumab + olaparib v control], 0.41 [95% CI, 0.21 to 0.75]) and pMMR subgroups (HR [durvalumab v control], 0.77 [95% CI, 0.60 to 0.97]; HR [durvalumab + olaparib v control] 0.57; [95% CI, 0.44 to 0.73]); and in PD-L1-positive subgroups (HR [durvalumab v control], 0.63 [95% CI, 0.48 to 0.83]; HR [durvalumab + olaparib v control], 0.42 [95% CI, 0.31 to 0.57]). Interim overall survival results (maturity approximately 28%) were supportive of the primary outcomes (durvalumab v control: HR, 0.77 [95% CI, 0.56 to 1.07]; P = .120; durvalumab + olaparib v control: HR, 0.59 [95% CI, 0.42 to 0.83]; P = .003). The safety profiles of the experimental arms were generally consistent with individual agents.

CONCLUSION

Carboplatin/paclitaxel plus durvalumab followed by maintenance durvalumab with or without olaparib demonstrated a statistically significant and clinically meaningful PFS benefit in patients with advanced or recurrent endometrial cancer.

Extracellular vesicles as a potential delivery platform for CRISPR-Cas based therapy in epithelial ovarian cancer

Ovarian Cancer (OC) is the most common gynecological malignancy and the eighth most diagnosed cancer in females worldwide. Presently, it ranks as the fifth leading cause of cancer-related mortality among patients globally. Major factors contributing to the lethality of OC worldwide include delayed diagnosis, chemotherapy resistance, high metastatic rates, and the heterogeneity of subtypes. Despite continuous efforts to develop novel targeted therapies and chemotherapeutic agents, challenges persist in the form of OC resistance and recurrence. In the last decade, CRISPR-Cas-based genome editing has emerged as a powerful tool for modifying genetic and epigenetic mechanisms, holding potential for treating numerous diseases. However, a significant challenge for therapeutic applications of CRISPR-Cas technology is the absence of an optimal vehicle for delivering CRISPR molecular machinery into targeted cells or tissues. Recently, extracellular vesicles (EVs) have gained traction as potential delivery vehicles for various therapeutic agents. These heterogeneous, membrane-derived vesicles are released by nearly all cells into extracellular spaces. They carry a molecular cargo of proteins and nucleic acids within their intraluminal space, encased by a cholesterol-rich phospholipid bilayer membrane. EVs actively engage in cell-to-cell communication by delivering cargo to both neighboring and distant cells. Their inherent ability to shield molecular cargo from degradation and cross biological barriers positions them ideally for delivering CRISPR-Cas ribonucleoproteins (RNP) to target cells. Furthermore, they exhibit higher biocompatibility, lower immunogenicity, and reduced toxicity compared to classical delivery platforms such as adeno-associated virus, lentiviruses, and synthetic nanoparticles. This review explores the potential of employing different CRISPR-Cas systems to target specific genes in OC, while also discussing various methods for engineering EVs to load CRISPR components and enhance their targeting capabilities.

CD4 T cells and toxicity from immune checkpoint blockade

Immune-related toxicities, otherwise known as immune-related adverse events (irAEs), occur in a substantial fraction of cancer patients treated with immune checkpoint inhibitors (ICIs). Ranging from asymptomatic to life-threatening, ICI-induced irAEs can result in hospital admission, high-dose corticosteroid treatment, ICI discontinuation, and in some cases, death. A deeper understanding of the factors underpinning severe irAE development will be essential for improved irAE prediction and prevention, toward maximizing the benefits and safety profiles of ICIs. In recent work, we applied mass cytometry, single-cell RNA sequencing, single-cell V(D)J sequencing, bulk RNA sequencing, and bulk T-cell receptor (TCR) sequencing to identify pretreatment determinants of severe irAE development in patients with advanced melanoma. Across 71 patients separated into three cohorts, we found that two baseline features in circulation-elevated activated CD4 effector memory T-cell abundance and TCR diversity-are associated with severe irAE development, independent of the affected organ system within 3 months of ICI treatment initiation. Here, we provide an extended perspective on this work, synthesize and discuss related literature, and summarize practical considerations for clinical translation. Collectively, these findings lay a foundation for data-driven and mechanistic insights into irAE development, with the potential to reduce ICI morbidity and mortality in the future.

Unravelling the Role of PARP1 in Homeostasis and Tumorigenesis: Implications for Anti-Cancer Therapies and Overcoming Resistance

Detailing the connection between homeostatic functions of enzymatic families and eventual progression into tumorigenesis is crucial to our understanding of anti-cancer therapies. One key enzyme group involved in this process is the Poly (ADP-ribose) polymerase (PARP) family, responsible for an expansive number of cellular functions, featuring members well established as regulators of DNA repair, genomic stability and beyond. Several PARP inhibitors (PARPi) have been approved for clinical use in a range of cancers, with many more still in trials. Unfortunately, the occurrence of resistance to PARPi therapy is growing in prevalence and requires the introduction of novel counter-resistance mechanisms to maintain efficacy. In this review, we summarize the updated understanding of the vast homeostatic functions the PARP family mediates and pin the importance of PARPi therapies as anti-cancer agents while discussing resistance mechanisms and current up-and-coming counter-strategies for countering such resistance.

Enhancing the anti-tumor response by combining DNA damage repair inhibitors in the treatment of solid tumors

The anti-cancer efficacy of anti-malignancy therapies is related to DNA damage. However, DNA damage-response mechanisms can repair DNA damage, failing anti-tumor therapy. The resistance to chemotherapy, radiotherapy, and immunotherapy remains a clinical challenge. Thus, new strategies to overcome these therapeutic resistance mechanisms are needed. DNA damage repair inhibitors (DDRis) continue to be investigated, with polyadenosine diphosphate ribose polymerase inhibitors being the most studied inhibitors. Evidence of their clinical benefits and therapeutic potential in preclinical studies is growing. In addition to their potential as a monotherapy, DDRis may play an important synergistic role with other anti-cancer therapies or in reversing acquired treatment resistance. Here we review the impact of DDRis on solid tumors and the potential value of combinations of different treatment modalities with DDRis for solid tumors.

The role of immune checkpoint inhibition in triple negative breast cancer

INTRODUCTION

Immunotherapy has revolutionized cancer treatment, including TNBC, which has limited options of treatment and poor prognosis. ICIs studied in TNBC include pembrolizumab, nivolumab, atezolizumab, and durvalumab. Initial studies exploring ICI monotherapy demonstrated promising yet limited responses. Subsequent studies, KEYNOTE 522 and KEYNOTE 355, which combined ICI with chemotherapy, have resulted in the FDA approval of pembrolizumab in the early-stage and metastatic setting, respectively.

AREAS COVERED

This article provides a comprehensive review of the role of ICI in the treatment of TNBC. We reviewed the trials that have evaluated ICI monotherapy, dual therapy, ICI in combination with chemotherapy, targeted therapy, vaccines and radiation. Additionally, we reviewed potential biomarkers of response and immune-related adverse events (irAEs). A literature search was conducted via PubMed and ClinicalTrials.gov as of 5 June 2023.

EXPERT OPINION

Various approaches combining immunotherapy with chemotherapy, targeted therapy, vaccines and radiation have been assessed. Pembrolizumab remains the only ICI approved in both the early stage and mTNBC. The role of adjuvant pembrolizumab in those who achieved pCR after neoadjuvant therapy is being investigated. Combining ICI with PARP inhibitors and radiation shows promise. More research is needed in identifying predictors of response. Monitoring of irAEs remains crucial.

PD-1/PD-L1 immune checkpoint blockade in ovarian cancer: dilemmas and opportunities

Immune checkpoint inhibitors (ICIs) have revolutionized treatment in oncology. Antibodies against PD-1/PD-L1 and ICI-based combinations are under clinical investigations in multiple cancers, including ovarian cancer. However, the success of ICIs has not materialized in ovarian cancer, which remains one of the few malignancies where ICIs exhibit modest efficacy as either monotherapy or combination therapy. In this review, we summarize completed and ongoing clinical trials of PD-1/PD-L1 blockade in ovarian cancer, categorize the underlying mechanisms of resistance emergence, and introduce candidate approaches to rewire the tumor microenvironment (TME) to potentiate anti-PD-1/PD-L1 antibodies. Teaser: The intrinsic resistance of ovarian cancer to PD-1/PD-L1 blockade could be overcome by advanced understanding of underlying mechanisms and discoveries of new actionable targets for combinatory treatment.

Immune Checkpoint Inhibitors Combined with Targeted Therapy: The Recent Advances and Future Potentials

Immune checkpoint inhibitors (ICIs) have revolutionized the therapeutic landscape of cancer and have been widely approved for use in the treatment of diverse solid tumors. Targeted therapy has been an essential part of cancer treatment for decades, and in most cases, a special drug target is required. Numerous studies have confirmed the synergistic effect of combining ICIs with targeted therapy. For example, triple therapy of PD-L1 inhibitor atezolizumab plus BRAF inhibitor vemurafenib and MEK inhibitor cobimetinib has been approved as the first-line treatment in advanced melanoma patients with BRAFV600 mutations. However, not all combinations of ICIs and targeted therapy work. Combining ICIs with EGFR inhibitors in non-small-cell lung cancer (NSCLC) with EGFR mutations only triggered toxicities and did not improve efficacy. Therefore, the efficacies of combinations of ICIs and different targeted agents are distinct. This review firstly and comprehensively covered the current status of studies on the combination of ICIs mainly referring to PD-1 and PD-L1 inhibitors and targeted drugs, including angiogenesis inhibitors, EGFR/HER2 inhibitors, PARP inhibitors and MAPK/ERK signaling pathway inhibitors, in the treatment of solid tumors. We discussed the underlying mechanisms, clinical efficacies, side effects, and potential predictive biomarkers to give an integrated view of the combination strategy and provide perspectives for future directions in solid tumors.

DNA Repair Deficiency Regulates Immunity Response in Cancers: Molecular Mechanism and Approaches for Combining Immunotherapy

Defects in DNA repair pathways can lead to genomic instability in multiple tumor types, which contributes to tumor immunogenicity. Inhibition of DNA damage response (DDR) has been reported to increase tumor susceptibility to anticancer immunotherapy. However, the interplay between DDR and the immune signaling pathways remains unclear. In this review, we will discuss how a deficiency in DDR affects anti-tumor immunity, highlighting the cGAS-STING axis as an important link. We will also review the clinical trials that combine DDR inhibition and immune-oncology treatments. A better understanding of these pathways will help exploit cancer immunotherapy and DDR pathways to improve treatment outcomes for various cancers.

Influence of chain length and branching on poly(ADP-ribose)-protein interactions

Hundreds of proteins interact with poly(ADP-ribose) (PAR) via multiple PAR interaction motifs, thereby regulating their physico-chemical properties, sub-cellular localizations, enzymatic activities, or protein stability. Here, we present a targeted approach based on fluorescence correlation spectroscopy (FCS) to characterize potential structure-specific interactions of PAR molecules of defined chain length and branching with three prime PAR-binding proteins, the tumor suppressor protein p53, histone H1, and the histone chaperone APLF. Our study reveals complex and structure-specific PAR-protein interactions. Quantitative Kd values were determined and binding affinities for all three proteins were shown to be in the nanomolar range. We report PAR chain length dependent binding of p53 and H1, yet chain length independent binding of APLF. For all three PAR binders, we found a preference for linear over hyperbranched PAR. Importantly, protein- and PAR-structure-specific binding modes were revealed. Thus, while the H1-PAR interaction occurred largely on a bi-molecular 1:1 basis, p53-and potentially also APLF-can form complex multivalent PAR-protein structures. In conclusion, our study gives detailed and quantitative insight into PAR-protein interactions in a solution-based setting at near physiological buffer conditions. The results support the notion of protein and PAR-structure-specific binding modes that have evolved to fit the purpose of the respective biochemical functions and biological contexts.

Molecular Features, Prognostic Value, and Cancer Immune Interactions of Angiogenesis-Related Genes in Ovarian Cancer

Angiogenesis is crucial to tumor growth and metastasis; it plays a key role in various cancers development and progression. However, the potential effects of angiogenesis-related genes (ARGs) in ovarian cancer (OC) remain to be further investigated. We discussed the characteristics changes of ARGs in 784 OC samples from genomic and transcriptional levels, as well as their expression patterns based on four distinct datasets. First, 784 OC patients were divided into three molecular subtypes, and the findings indicated that ARG changes were correlated with clinicopathological parameters, prognosis, and immune cell-infiltrating tumor microenvironment (TME). OC patients were subsequently divided into two gene subtypes depending on differentially expressed genes (DEGs) of the abovementioned molecular subtypes. We also established an ARGs-related score (ARGs score) model for evaluating overall survival (OS) and determining the immunological landscape of OC patients, therefore predicting patients' prognosis and therapeutic responses. A lower ARGs' score accompanied by a high mutation frequency implies a higher probability of survival. Furthermore, the ARG score was correlated with the cancer stem cell (CSC) index and chemotherapeutic sensitivity. The significant involvement of ARGs in the tumor-immune-stromal microenvironment, clinicopathological characteristics, and prognosis were established in our systematic investigation of ARGs for OC patients. These discoveries might help us to better understand the role of ARGs in OC, as well as give new insight for predicting the prognosis and providing promising immunotherapy.

Nucleic acid vaccination strategies for ovarian cancer

High grade serous carcinoma (HGSC) is one of the most lethal ovarian cancers that is characterised by asymptomatic tumour growth, insufficient knowledge of malignant cell origin and sub-optimal detection. HGSC has been recently shown to originate in the fallopian tube and not in the ovaries. Conventional treatments such as chemotherapy and surgery depend upon the stage of the disease and have resulted in higher rates of relapse. Hence, there is a need for alternative treatments. Differential antigen expression levels have been utilised for early detection of the cancer and could be employed in vaccination strategies using nucleic acids. In this review the different vaccination strategies in Ovarian cancer are discussed and reviewed. Nucleic acid vaccination strategies have been proven to produce a higher CD8+ CTL response alongside CD4+ T-cell response when compared to other vaccination strategies and thus provide a good arena for antitumour immune therapy. DNA and mRNA need to be delivered into the intracellular matrix. To overcome ineffective naked delivery of the nucleic acid cargo, a suitable delivery system is required. This review also considers the suitability of cell penetrating peptides as a tool for nucleic acid vaccine delivery in ovarian cancer.

Ginsenosides: Allies of gastrointestinal tumor immunotherapy

In the past decade, immunotherapy has been the most promising treatment for gastrointestinal tumors. But the low response rate and drug resistance remain major concerns. It is therefore imperative to develop adjuvant therapies to increase the effectiveness of immunotherapy and prevent drug resistance. Ginseng has been used in Traditional Chinese medicine as a natural immune booster for thousands of years. The active components of ginseng, ginsenosides, have played an essential role in tumor treatment for decades and are candidates for anti-tumor adjuvant therapy. They are hypothesized to cooperate with immunotherapy drugs to improve the curative effect and reduce tumor resistance and adverse reactions. This review summarizes the research into the use of ginsenosides in immunotherapy of gastrointestinal tumors and discusses potential future applications.

Targeting DNA damage response as a potential therapeutic strategy for head and neck squamous cell carcinoma

Cells experience both endogenous and exogenous DNA damage daily. To maintain genome integrity and suppress tumorigenesis, individuals have evolutionarily acquired a series of repair functions, termed DNA damage response (DDR), to repair DNA damage and ensure the accurate transmission of genetic information. Defects in DNA damage repair pathways may lead to various diseases, including tumors. Accumulating evidence suggests that alterations in DDR-related genes, such as somatic or germline mutations, single nucleotide polymorphisms (SNPs), and promoter methylation, are closely related to the occurrence, development, and treatment of head and neck squamous cell carcinoma (HNSCC). Despite recent advances in surgery combined with radiotherapy, chemotherapy, or immunotherapy, there has been no substantial improvement in the survival rate of patients with HNSCC. Therefore, targeting DNA repair pathways may be a promising treatment for HNSCC. In this review, we summarized the sources of DNA damage and DNA damage repair pathways. Further, the role of DNA damage repair pathways in the development of HNSCC and the application of small molecule inhibitors targeting these pathways in the treatment of HNSCC were focused.

Efficacy evaluation of multi-immunotherapy in ovarian cancer: From bench to bed

Ovarian cancer, one of the most common gynecological malignancies, is characterized by high mortality and poor prognosis. Cytoreductive surgery and chemotherapy remain the mainstay of ovarian cancer treatment, and most women experience recurrence after standard care therapies. There is compelling evidence that ovarian cancer is an immunogenic tumor. For example, the accumulation of tumor-infiltrating lymphocytes is associated with increased survival, while increases in immunosuppressive regulatory T cells are correlated with poor clinical outcomes. Therefore, immunotherapies targeting components of the tumor microenvironment have been gradually integrated into the existing treatment options, including immune checkpoint blockade, adoptive cell therapy, and cancer vaccines. Immunotherapies have changed guidelines for maintenance treatment and established a new paradigm in ovarian cancer treatment. Despite single immunotherapies targeting DNA repair mechanisms, immune checkpoints, and angiogenesis bringing inspiring efficacy, only a subset of patients can benefit much from it. Thus, the multi-immunotherapy investigation remains an active area for ovarian cancer treatment. The current review provides an overview of various clinically oriented forms of multi-immunotherapy and explores potentially effective combinational therapies for ovarian cancer.

A Novel PARP Inhibitor YHP-836 For the Treatment of BRCA-Deficiency Cancers

PARP inhibitors have clinically demonstrated good antitumor activity in patients with BRCA mutations. Here, we described YHP-836, a novel PARP inhibitor, YHP-836 demonstrated excellent inhibitory activity for both PARP1 and PARP2 enzymes. It also allosterically regulated PARP1 and PARP2 via DNA trapping. YHP-836 showed cytotoxicity in tumor cell lines with BRCA mutations and induced cell cycle arrest in the G2/M phase. YHP-836 also sensitized tumor cells to chemotherapy agents in vitro. Oral administration of YHP-836 elicited remarkable antitumor activity either as a single agent or in combination with chemotherapy agents in vivo. These results indicated that YHP-836 is a well-defined PARP inhibitor.

Improving ovarian cancer treatment decision using a novel risk predictive tool

BACKGROUND

As a major component of the tumor tissue, the tumor microenvironment (TME) has been proven to associate with tumor progression and immunotherapy. Ovarian cancer accounts for the highest mortality rate among gynecologic malignancies. Its clinical treatment decision is highly correlated with the prognosis, underscoring the need to evaluate the prognosis and choose the proper clinical treatment through TME information.

METHOD

This study constructs a score with TME information obtained by the CIBERSORT algorithm, which classifies the patients into high and low TMEscore groups with quantified TME infiltration patterns through the PCA algorithm. TMEscore was constructed by TCGA cohort and validated in GEO cohort. Univariate and multivariate Cox proportional hazards model analyses were used to demonstrate prognostic value of TMEscore in overall and stratified analysis.

RESULT

TMEscore is highly correlated with survival and high TMEscore group has a better prognosis. In order to improve treatment decision, the expression of immune checkpoints, immunophenoscore (IPS) and ESTIMATE score showed a high TMEscore have a better immune microenvironment and respond better to immune checkpoint inhibitors (ICIs). Meanwhile, the mutation landscape between TMEscore groups was profiled, and 13 genes were found mutated differently between the two groups. Among them, BRCA1 has more mutations in the high TMEscore group and speculated that high TMEscore patients might be a beneficiary population of PARP inhibitors combined with immunotherapy.

CONCLUSION

TMEscore based on TME with prognostic value and clinical value is proposed for the identification of targets treatment and immunotherapy strategies for ovarian cancer.

The STING pathway: Therapeutic vulnerabilities in ovarian cancer

Ovarian cancer is the leading cause of mortality due to gynecologic malignancy. The majority of women diagnosed with the most common subtype, high-grade serous ovarian carcinoma (HGSC), develop resistance to conventional therapies despite initial response to treatment. HGSC tumors displaying DNA damage repair (DDR) gene deficiency and high chromosomal instability mainly associate with higher cytotoxic immune cell infiltration and expression of genes associated with these immune pathways. Despite the high level of immune infiltration observed, the majority of patients with HGSC have not benefited from immunomodulatory treatments as the mechanistic basis of this infiltration is unclear. This lack of response can be primarily attributed to heterogeneity at the levels of both cancer cell genetic alterations and the tumour immune microenvironment. Strategies to enhance anti-tumour immunity have been investigated in ovarian cancer, of which interferon activating therapies present as an attractive option. Of the several type I interferon (IFN-1) stimulating therapies, exogenously activating the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway is emerging as a promising avenue. Herein, we highlight our current understanding of how constitutive and induced cGAS-STING pathway activation influences the ovarian tumour microenvironment. We further elaborate on the links between the genomic alterations prevalent in ovarian tumours and how the resultant immune phenotypes can make them more susceptible to exogenous STING pathway activation and potentiate immune-mediated killing of cancer cells. The therapeutic potential of cGAS-STING pathway activation in ovarian cancer and factors implicating treatment outcomes are discussed, providing a rationale for future combinatorial treatment approaches on the backbone of chemotherapy.

ATR and CDK4/6 inhibition target the growth of methotrexate-resistant choriocarcinoma

Low-risk gestational trophoblastic neoplasia including choriocarcinoma is often effectively treated with Methotrexate (MTX) as a first line therapy. However, MTX resistance (MTX-R) occurs in at least ≈33% of cases. This can sometimes be salvaged with actinomycin-D but often requires more toxic combination chemotherapy. Moreover, additional therapy may be needed and, for high-risk patients, 5% still die from the multidrug-resistant disease. Consequently, new treatments that are less toxic and could reverse MTX-R are needed. Here, we compared the proteome/phosphoproteome of MTX-resistant and sensitive choriocarcinoma cells using quantitative mass-spectrometry to identify therapeutically actionable molecular changes associated with MTX-R. Bioinformatics analysis of the proteomic data identified cell cycle and DNA damage repair as major pathways associated with MTX-R. MTX-R choriocarcinoma cells undergo cell cycle delay in G1 phase that enables them to repair DNA damage more efficiently through non-homologous end joining in an ATR-dependent manner. Increased expression of cyclin-dependent kinase 4 (CDK4) and loss of p16^Ink4a in resistant cells suggested that CDK4 inhibition may be a strategy to treat MTX-R choriocarcinoma. Indeed, inhibition of CDK4/6 using genetic silencing or the clinically relevant inhibitor, Palbociclib, induced growth inhibition both in vitro and in an orthotopic in vivo mouse model. Finally, targeting the ATR pathway, genetically or pharmacologically, re-sensitised resistant cells to MTX in vitro and potently prevented the growth of MTX-R tumours in vivo. In short, we identified two novel therapeutic strategies to tackle MTX-R choriocarcinoma that could rapidly be translated into the clinic.

Dual-target inhibitors of poly (ADP-ribose) polymerase-1 for cancer therapy: Advances, challenges, and opportunities

PARP1 plays a crucial role in DNA damage repair, making it an essential target for cancer therapy. PARP1 inhibitors are widely used to treat BRCA-deficient malignancies, and six PARP inhibitors have been approved for clinical use. However, excluding the great clinical success of PARP inhibitors, the concomitant toxicity, drug resistance, and limited scope of application restrict their clinical efficacy. To find solutions to these problems, dual-target inhibitors have shown great potential. In recent years, several studies have linked PAPR1 to other primary cancer targets. Many dual-target inhibitors have been developed using structural fusion, linkage, or library construction methods, overcoming the defects of many single-target inhibitors of PARP1 and achieving great success in clinical cancer therapy. This review summarizes the advance of dual-target PARP1 inhibitors in recent years, focusing on their structural optimization process, structure-activity relationships (SARs), and in vitro or in vivo analysis results.

UCP1 modulates immune infiltration level and survival outcome in ovarian cancer patients

Background

The uncoupling proteins (UCPs) are critical genes associated with tumorigenesis and chemoresistance. However, little is known about the molecular mechanism of the UCPs in ovarian cancer (OV).

Material and methods

UCPs expression analysis was conducted using Gene Expression Profiling Interactive Analysis (GEPIA), and its potential in clinical prognosis was analyzed using Kaplan- Meier analyses. The influence of UCPs on immune infiltration was analyzed by TIMER. In addition, the correlation between UCPs expression and molecular mechanisms was investigated by TIMER and Cancer Single-cell State Atlas (CancerSEA).

Results

UCP1, UCP2, UCP3 and UCP5 expression levels correlated with a favorable prognosis and tumor progression. Moreover, UCP1 expression correlated to several immune cell markers and regulated tumorigenesis, such as tumor invasion, EMT, metastasis and DNA repair. In addition, UCP1 potentially involved in genes expression of SNAI2, MMP2, BRCA1 and PARP1.

Conclusions

These results implied a critical role of UCP1 in the prognosis and immune infiltration of ovarian cancer. In addition, UCP1 expression participated in regulating multiple oncogenes and tumorigenesis.

Overview of Immune Checkpoint Inhibitors in Gynecological Cancer Treatment

In the last ten years, clinical oncology has been revolutionized by the introduction of oncological immunotherapy, mainly in the form of immune checkpoint inhibitors (ICIs) that transformed the standard of care of several advanced solid malignancies. Using ICIs for advanced gynecological cancers has yielded good results, especially for endometrial cancer. In ovarian or cervical cancer, combining ICIs with other established agents has shown some promise. Concurrently with the clinical development of ICIs, biomarkers that predict responses to such therapy have been discovered and used in clinical trials. The translation of these biomarkers to clinical practice was somewhat hampered by lacking assay standardization and non-comprehensive reporting of biomarker status in trials often performed on a small number of gynecological cancer patients. We can expect increased use of ICIs combined with other agents in gynecological cancer in the near future. This will create a need for reliable response prediction tools, which we believe will be based on biomarker, clinical, and tumor characteristics. In this article, we review the basic biology of ICIs and response prediction biomarkers, as well as the latest clinical trials that focus on subgroup effectiveness based on biomarker status in gynecological cancer patients.

The developing landscape of combinatorial therapies of immune checkpoint blockade with DNA damage repair inhibitors for the treatment of breast and ovarian cancers

The use of immune checkpoint blockade (ICB) using antibodies against programmed death receptor (PD)-1, PD ligand (PD-L)-1, and cytotoxic T-lymphocyte antigen 4 (CTLA-4) has redefined the therapeutic landscape in solid tumors, including skin, lung, bladder, liver, renal, and breast tumors. However, overall response rates to ICB therapy remain limited in PD-L1-negative patients. Thus, rational and effective combination therapies will be needed to address ICB treatment resistance in these patients, as well as in PD-L1-positive patients who have progressed under ICB treatment. DNA damage repair inhibitors (DDRis) may activate T-cell responses and trigger inflammatory cytokines release and eventually immunogenic cancer cell death by amplifying DNA damage and generating immunogenic neoantigens, especially in DDR-defective tumors. DDRi may also lead to adaptive PD-L1 upregulation, providing a rationale for PD-L1/PD-1 blockade. Thus, based on preclinical evidence of efficacy and no significant overlapping toxicity, some ICB/DDRi combinations have rapidly progressed to clinical testing in breast and ovarian cancers. Here, we summarize the available clinical data on the combination of ICB with DDRi agents for treating breast and ovarian cancers and discuss the mechanisms of action and other lessons learned from translational studies conducted to date. We also review potential biomarkers to select patients most likely to respond to ICB/DDRi combination therapy.

Construction of a Macrophage Infiltration Regulatory Network and Related Prognostic Model of High-Grade Serous Ovarian Cancer

Background

High-grade serous ovarian cancer (HGSOC) carries the highest mortality in the gynecological cancers; however, therapeutic outcomes have not significantly improved in recent decades. Macrophages play an essential role in the occurrence and development of ovarian cancer, so the mechanisms of macrophage infiltration should be elucidated.

Method

We downloaded transcriptome data of ovarian cancers from the Gene Expression Omnibus and The Cancer Genome Atlas. After rigorous screening, 1566 HGSOC were used for data analysis. CIBERSORT was used to estimate the level of macrophage infiltration and WGCNA was used to identify macrophage-related modules. We constructed a macrophage-related prognostic model using machine learning LASSO algorithm and verified it using multiple HGSOC cohorts.

Results

In the GPL570-OV cohort, high infiltration level of M1 macrophages was associated with a good outcome, while high infiltration level of M2 macrophages was associated with poor outcomes. We used WGCNA to select genes correlated with macrophage infiltration. These genes were used to construct protein-protein interaction maps of macrophage infiltration. IFL44L, RSAD2, IFIT3, MX1, IFIH1, IFI44, and ISG15 were the hub genes in the network. We then constructed a macrophage-related prognostic model composed of CD38, ACE2, BATF2, HLA-DOB, and WARS. The model had the ability to predict the overall survival rate of HGSOC patients in GPL570-OV, GPL6480-OV, TCGA-OV, GSE50088, and GSE26712. In exploring the immune microenvironment, we found that CD4 memory T cells and activated mast cells showed that the degree of infiltration was higher in the high-risk group, while M1 macrophages were the opposite, and HLA molecules were overexpressed in the high-risk group.

Conclusion

We constructed a macrophage infiltration-related protein interaction network that provides a basis for studying macrophages in HGSOC. Our macrophage-related prognostic model is robust and widely applicable. It predicts overall survival in HGSOC patients and may improve HGSOC treatment.

Veliparib in Combination With Platinum-Based Chemotherapy for First-Line Treatment of Advanced Squamous Cell Lung Cancer: A Randomized, Multicenter Phase III Study

PURPOSE

Squamous non-small-cell lung cancer (sqNSCLC) is genetically complex with evidence of DNA damage. This phase III study investigated the efficacy and safety of poly (ADP-ribose) polymerase inhibitor veliparib in combination with conventional chemotherapy for advanced sqNSCLC (NCT02106546).

PATIENTS AND METHODS

Patients age ≥ 18 years with untreated, advanced sqNSCLC were randomly assigned 1:1 to carboplatin and paclitaxel with veliparib 120 mg twice daily (twice a day) or placebo twice a day for up to six cycles. The primary end point was overall survival (OS) in the veliparib arm versus the control arm in current smokers, based on phase II findings. Archival tumor samples were provided for biomarker analysis using a 52-gene expression histology classifier (LP52).

RESULTS

Overall, 970 patients were randomly assigned to carboplatin and paclitaxel plus either veliparib (n = 486) or placebo (n = 484); 57% were current smokers. There was no significant OS benefit with veliparib in current smokers, with median OS 11.9 versus 11.1 months (hazard ratio [HR], 0.905; 95% CI, 0.744 to 1.101; P = .266). In the overall population, OS favored veliparib; median OS was 12.2 versus 11.2 months (HR, 0.853; 95% CI, 0.747 to 0.974), with no difference in progression-free survival (median 5.6 months per arm). In patients with biomarker-evaluable tumor samples (n = 360), OS favored veliparib in the LP52-positive population (median 14.0 v 9.6 months; HR, 0.66; 95% CI, 0.49 to 0.89), but favored placebo in the LP52-negative population (median 11.0 v 14.4 months; HR, 1.33; 95% CI, 0.95 to 1.86). No new safety signals were observed in the experimental arm.

CONCLUSION

In current smokers with advanced sqNSCLC, there was no therapeutic benefit of adding veliparib to first-line chemotherapy. The LP52 signature may identify a subgroup of patients likely to derive benefit from veliparib with chemotherapy.

A combination of PARP and CHK1 inhibitors efficiently antagonizes MYCN-driven tumors

MYCN drives aggressive behavior and refractoriness to chemotherapy, in several tumors. Since MYCN inactivation in clinical settings is not achievable, alternative vulnerabilities of MYCN-driven tumors need to be explored to identify more effective and less toxic therapies. We previously demonstrated that PARP inhibitors enhance MYCN-induced replication stress and promote mitotic catastrophe, counteracted by CHK1. Here, we showed that PARP and CHK1 inhibitors synergized to induce death in neuroblastoma cells and in primary cultures of SHH-dependent medulloblastoma, their combination being more effective in MYCN amplified and MYCN overexpressing cells compared to MYCN non-amplified cells. Although the MYCN amplified IMR-32 cell line carrying the p.Val2716Ala ATM mutation showed the highest sensitivity to the drug combination, this was not related to ATM status, as indicated by CRISPR/Cas9-based correction of the mutation. Suboptimal doses of the CHK1 inhibitor MK-8776 plus the PARP inhibitor olaparib led to a MYCN-dependent accumulation of DNA damage and cell death in vitro and significantly reduced the growth of four in vivo models of MYCN-driven tumors, without major toxicities. Our data highlight the combination of PARP and CHK1 inhibitors as a new potential chemo-free strategy to treat MYCN-driven tumors, which might be promptly translated into clinical trials.

BRCA mutations in pancreatic cancer and progress in their targeting

Introduction: Genomic instability resulting from DNA damage repair (DDR) deficiencies is a hallmark of cancer and offers treatment opportunities. Homologous recombination DDR defect is a result of multiple critical gene mutations, including BRCA1/2. Targeting DNA DDR defects in pancreatic cancer (PC) is emerging as a potential treatment strategy with current focus on BRCA mutations.Areas covered: Challenges in treating patients with PC are explained. We review DDR defects as a treatment target in PC, specifically, germline BRCA mutation and sensitivity to platinum compounds and exploiting the strategy of synthetic lethality using poly (ADP-ribose) polymerase (PARP) inhibition. Literature review was undertaken through PubMed, Google Scholar, and Clinicaltrials.gov website.Expert opinion: DDR defects are promising targets for novel therapies in PC. Early application of such strategy is in patient subgroup with BRCA germline mutation, which is seen in only 5-7% of the PC population. The oral PARP inhibitor olaparib in the maintenance setting represents the first targeted therapy in metastatic PC based on a phase 3 study. There is a very modest benefit for patients with PC using PARP inhibitors. Future work must improve our understanding of mechanisms of sensitivity and resistance to PARP inhibitors in PC and enhance the molecular selection of patients for such therapy.

An Immune-Related Gene-Based Signature as Prognostic Tool in Ovarian Serous Cystadenocarcinoma

Background

Ovarian serous cystadenocarcinoma (OSCC) is a life-threatening malignancy with poor prognosis. Therefore, the identification of immune-related genes associated with OSCC prognosis may reveal new targets of immunotherapy for OSCC.

Patients and Methods

The gene expression profiles of overlapped genes were extracted by weighted gene co-expression network analysis (WGCNA) to identify immune-related modules. Significant genes were identified by univariate Cox regression analysis of model genes. Model characteristic genes were obtained by least absolute shrinkage and selection operator (LASSO) analysis and used to calculate a “signature index”. The model’s ability to predict prognosis in OSCC patients was assessed using time-dependent receiver operator characteristic curves. Differences in the biological processes and Kyoto Encyclopedia of Genes and Genomes pathways between groups with high or low signature index were assessed using gene set enrichment analysis (GSEA). The types of immune cells and their abundance in the two index groups were explored by single-sample GSEA.

Results

The expression profiles of 3517 overlapped genes were extracted by WGCNA, and nine modules related to the immune system of OSCC were obtained. The expression profiles of 114 hub genes were then subjected to LASSO analysis. Among them, 10 immune-related genes were significant, of which six were identified as model characteristic genes and were used to calculate the signature index. Moreover, 24 types of immune cells were identified in the tumor microenvironment, and their abundance was explored in high- and low-signature index groups of two datasets.

Conclusion

ARHGEF18, PLEKHA7, MTOR, VPS45, BRCA1, and HINT2 were identified as characteristic genes and used to develop a new immune-related gene-based signature as a promising prognostic biomarker for OSCC.

Leveraging NKG2D Ligands in Immuno-Oncology

Immune checkpoint inhibitors (ICI) revolutionized the field of immuno-oncology and opened new avenues towards the development of novel assets to achieve durable immune control of cancer. Yet, the presence of tumor immune evasion mechanisms represents a challenge for the development of efficient treatment options. Therefore, combination therapies are taking the center of the stage in immuno-oncology. Such combination therapies should boost anti-tumor immune responses and/or target tumor immune escape mechanisms, especially those created by major players in the tumor microenvironment (TME) such as tumor-associated macrophages (TAM). Natural killer (NK) cells were recently positioned at the forefront of many immunotherapy strategies, and several new approaches are being designed to fully exploit NK cell antitumor potential. One of the most relevant NK cell-activating receptors is NKG2D, a receptor that recognizes 8 different NKG2D ligands (NKG2DL), including MICA and MICB. MICA and MICB are poorly expressed on normal cells but become upregulated on the surface of damaged, transformed or infected cells as a result of post-transcriptional or post-translational mechanisms and intracellular pathways. Their engagement of NKG2D triggers NK cell effector functions. Also, MICA/B are polymorphic and such polymorphism affects functional responses through regulation of their cell-surface expression, intracellular trafficking, shedding of soluble immunosuppressive isoforms, or the affinity of NKG2D interaction. Although immunotherapeutic approaches that target the NKG2D-NKG2DL axis are under investigation, several tumor immune escape mechanisms account for reduced cell surface expression of NKG2DL and contribute to tumor immune escape. Also, NKG2DL polymorphism determines functional NKG2D-dependent responses, thus representing an additional challenge for leveraging NKG2DL in immuno-oncology. In this review, we discuss strategies to boost MICA/B expression and/or inhibit their shedding and propose that combination strategies that target MICA/B with antibodies and strategies aimed at promoting their upregulation on tumor cells or at reprograming TAM into pro-inflammatory macrophages and remodeling of the TME, emerge as frontrunners in immuno-oncology because they may unleash the antitumor effector functions of NK cells and cytotoxic CD8 T cells (CTL). Pursuing several of these pipelines might lead to innovative modalities of immunotherapy for the treatment of a wide range of cancer patients.

Intersection of Two Checkpoints: Could Inhibiting the DNA Damage Response Checkpoint Rescue Immune Checkpoint-Refractory Cancer?

Metastatic cancers resistant to immunotherapy require novel management strategies. DNA damage response (DDR) proteins, including ATR (ataxia telangiectasia and Rad3-related), ATM (ataxia telangiectasia mutated) and DNA-PK (DNA-dependent protein kinase), have been promising therapeutic targets for decades. Specific, potent DDR inhibitors (DDRi) recently entered clinical trials. Surprisingly, preclinical studies have now indicated that DDRi may stimulate anti-tumor immunity to augment immunotherapy. The mechanisms governing how DDRi could promote anti-tumor immunity are not well understood; however, early evidence suggests that they can potentiate immunogenic cell death to recruit and activate antigen-presenting cells to prime an adaptive immune response. Merkel cell carcinoma (MCC) is well suited to test these concepts. It is inherently immunogenic as ~50% of patients with advanced MCC persistently benefit from immunotherapy, making MCC one of the most responsive solid tumors. As is typical of neuroendocrine cancers, dysfunction of p53 and Rb with upregulation of Myc leads to the very rapid growth of MCC. This suggests high replication stress and susceptibility to DDRi and DNA-damaging agents. Indeed, MCC tumors are particularly radiosensitive. Given its inherent immunogenicity, cell cycle checkpoint deficiencies and sensitivity to DNA damage, MCC may be ideal for testing whether targeting the intersection of the DDR checkpoint and the immune checkpoint could help patients with immunotherapy-refractory cancers.

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.

Shaping Immune Responses in the Tumor Microenvironment of Ovarian Cancer

Reciprocal signaling between immune cells and ovarian cancer cells in the tumor microenvironment can alter immune responses and regulate disease progression. These signaling events are regulated by multiple factors, including genetic and epigenetic alterations in both the ovarian cancer cells and immune cells, as well as cytokine pathways. Multiple immune cell types are recruited to the ovarian cancer tumor microenvironment, and new insights about the complexity of their interactions have emerged in recent years. The growing understanding of immune cell function in the ovarian cancer tumor microenvironment has important implications for biomarker discovery and therapeutic development. This review aims to describe the factors that shape the phenotypes of immune cells in the tumor microenvironment of ovarian cancer and how these changes impact disease progression and therapy.

Checkpoint Kinase 1 (Chk1) inhibition fails to activate the Stimulator of Interferon Genes (STING) innate immune signalling in a human coculture cancer system

Utilising Checkpoint Kinase 1 (Chk1) inhibitors to increase cytoplasmic DNA may be a potential strategy to increase the sensitivity of tumours to immune checkpoint modulators. The appearance of DNA in the cytoplasm can drive Cyclic GMP-AMP Synthase-2',3'-Cyclic Guanosine Monophosphate-Adenosine Monophosphate-Stimulator of Interferon Genes (cGAS-cGAMP-STING) inflammatory, anti-tumour T-cell activity via a type I interferon (IFN) and nuclear factor-κB response. In the THP1-Dual reporter cell line, the STING agonist cGAMP activated both reporters, and increased phosphorylation of the innate immune pathway signallers Tank Binding Kinase 1 (TBK1) and Interferon Regulatory Factor (IRF) 3. Inhibition of Chk1 increased TBK1 but not IRF3 phosphorylation and did not induce IRF or NF-κB reporter activation. cGAMP induced a Type I IFN response in THP1 cells whereas inhibition of Chk1 did not. HT29 or HCC1937 cell treatment with a Chk1 inhibitor increased cytoplasmic dsDNA in treated HCC1937 but not HT29 cells and increased IRF reporter activation in cocultured THP1-Dual cells. HT29 cells pre-treated with gemcitabine or camptothecin had elevated cytoplasmic dsDNA and IRF reporter activation in cocultured THP1-Dual cells. Camptothecin or gemcitabine plus a Chk1 inhibitor increased cytoplasmic dsDNA but Chk1 inhibition suppressed IRF reporter activation in cocultured THP1 cells. In THP1-Dual cells treated with cGAMP, Chk1 inhibition suppressed the activation of the IRF reporter compared to cGAMP alone. These results suggest that, in some cellular models, there is little evidence to support the combination of Chk1 inhibitors with immune checkpoint modulators and, in some combination regimes, may even prove deleterious.

A Review of the Clinical Characteristics and Novel Molecular Subtypes of Endometrioid Ovarian Cancer

Ovarian cancer is one of the most common gynecologic cancers that has the highest mortality rate. Endometrioid ovarian cancer, a distinct subtype of epithelial ovarian cancer, is associated with endometriosis and Lynch syndrome, and is often accompanied by synchronous endometrial carcinoma. In recent years, dysbiosis of the microbiota within the female reproductive tract has been suggested to be involved in the pathogenesis of endometrial cancer and ovarian cancer, with some specific pathogens exhibiting oncogenic having been found to contribute to cancer development. It has been shown that dysregulation of the microenvironment and accumulation of mutations are stimulatory factors in the progression of endometrioid ovarian carcinoma. This would be a potential therapeutic target in the future. Simultaneously, multiple studies have demonstrated the role of four molecular subtypes of endometrioid ovarian cancer, which are of particular importance in the prediction of prognosis. This literature review aims to compile the potential mechanisms of endometrioid ovarian cancer, molecular characteristics, and molecular pathological types that could potentially play a role in the prediction of prognosis, and the novel therapeutic strategies, providing some guidance for the stratified management of ovarian cancer.

NLR and BRCA mutational status in patients with high grade serous advanced ovarian cancer

Laboratory-markers of the systemic inflammatory-response, such as neutrophil/lymphocyte-ratio (NLR) have been studied as prognostic factors in several tumors but in OC-patients their role is still controversial and no data about the possible correlation with the BRCA-status has been ever reported. We consecutively enrolled a series of 397 newly diagnosed high-grade serous-advanced OC-patients. All patients were tested for BRCA-mutational-status and blood-parameters have been collected 48 h before staging-surgery. A significant correlation of NLR with disease distribution (p < 0.005) was found and patients with NLR < 4 underwent primary-debulking-surgery more frequently (p-value 0.001), with a lower surgical-complexity-score (p-value 0.002). Regarding survival-data, patients with NLR < 4 had a significant 7-month increase in mPFS (26 vs 19 months, p = 0.009); focusing on the BRCA-status, among both BRCA-mutated and BRCA-wild type patients, those with lower NLR had a significantly prolonged mPFS compared to patients with NLR > 4 (BRCA-mutated: 35 vs 23 months, p = 0.03; BRCA-wt: 19 vs 16 months, p = 0.05). At multivariate-analysis, independent factors of prolonged PFS were BRCA mutational status, having received complete cytoreduction and NLR < 4. Also, the strongest predictors of longer OS were BRCA-mutational status, having received complete cytoreductive surgery, NLR < 4 and age. NLR is confirmed to be a prognostic marker in OC-patients and it seems unrelated with BRCA-mutational status.

PARP inhibitors: shifting the paradigm in the treatment of pancreatic cancer

Pancreatic cancer, being one of the most fatal cancers, is the 7th leading cause of death globally. Cancer that is resistant to current treatment proves that there is a need for personalized and targeted therapy, based on the tumor and genomic markers. Pembrolizumab and Larotrectinib are examples of current medications used as targeted therapy in pancreatic cancer. Pancreatic cancer has many different molecular subgroups, providing the opportunity for the development of new drugs that can target these groups. Poly (ADP-Ribose) polymerase inhibitors (PARPi) are a group of drugs inhibiting PARP to decrease the stability of the cancer cells. Currently, PARPi are mostly used in ovarian and breast cancer. There are multiple studies that have shown positive effects of PARPi in decreasing the tumor burden in advanced pancreatic cancer. PARPi are the future of pancreatic cancer management, and hence it is important to understand their mechanism, resistance pathways, and their application in the real world.

Assessing Preclinical Research Models for Immunotherapy for Gynecologic Malignancies

Gynecologic malignancies are increasing in incidence, with a plateau in clinical outcomes necessitating novel treatment options. Immunotherapy and modulation of the tumor microenvironment are rapidly developing fields of interest in gynecologic oncology translational research; examples include the PD-1 (programmed cell death 1) and CTLA-4 (cytotoxic T-lymphocyte-associated protein 4) axes and the Wnt pathway. However, clinical successes with these agents have been modest and lag behind immunotherapy successes in other malignancies. A thorough contextualization of preclinical models utilized in gynecologic oncology immunotherapy research is necessary in order to effectively and efficiently develop translational medicine. These include murine models, in vitro assays, and three-dimensional human-tissue-based systems. Here, we provide a comprehensive review of preclinical models for immunotherapy in gynecologic malignancies, including benefits and limitations of each, in order to inform study design and translational research models. Improved model design and implementation will optimize preclinical research efficiency and increase the translational value to positive findings, facilitating novel treatments that improve patient outcomes.

Evolving Role of Immunotherapy in Metastatic Castration Refractory Prostate Cancer

Immunotherapies have shown remarkable success in the treatment of multiple cancer types; however, despite encouraging preclinical activity, registration trials of immunotherapy in prostate cancer have largely been unsuccessful. Sipuleucel-T remains the only approved immunotherapy for the treatment of asymptomatic or minimally symptomatic metastatic castrate-resistant prostate cancer based on modest improvement in overall survival. This immune evasion in the case of prostate cancer has been attributed to tumor-intrinsic factors, an immunosuppressive tumor microenvironment, and host factors, which ultimately make it an inert 'cold' tumor. Recently, multiple approaches have been investigated to turn prostate cancer into a 'hot' tumor. Antibodies directed against programmed cell death protein 1 have a tumor agnostic approval for a small minority of patients with microsatellite instability-high or mismatch repair-deficient metastatic prostate cancer. Herein, we present an overview of the current immunotherapy landscape in metastatic castration-resistant prostate cancer with a focus on immune checkpoint inhibitors. We describe the results of clinical trials of immune checkpoint inhibitors in patients with metastatic castration-resistant prostate cancer; either as single agents or in combination with other checkpoint inhibitors, poly (ADP-ribose) polymerase (PARP) inhibitors, tyrosine kinase inhibitors, novel hormonal therapies, chemotherapies, and radioligands. Finally, we review upcoming immunotherapies, including novel monoclonal antibodies, chimeric-antigen receptor (CAR) T cells, Bi-Specific T cell Engagers (BiTEs), therapies targeting the adenosine pathway, and other miscellaneous agents.

The chemical biology of IL-12 production via the non-canonical NFkB pathway

Interleukin-12 (IL-12) has emerged as an attractive cytokine for cancer therapy because it has direct anti-cancer effects and additionally plays a critical role in enhancing checkpoint inhibitors. Given these multiple modes of actions, identifying means to pharmacologically induce IL-12 production in the tumor microenvironment has become important. In this review, we highlight therapeutics that promote IL-12 induction in tumor-associated myeloid cells through the non-canonical NFkB pathway. We discuss existing clinical trials and briefly examine the additional pathway targets that warrant further exploration for drug discovery.