New Approaches for Immune Directed Treatment for Ovarian Cancer

Investigating the mechanisms of drug resistance and prognosis in ovarian cancer using single-cell RNA sequencing and bulk RNA sequencing

Ovarian cancer stands as a prevalent malignancy within the realm of gynecology, and the emergence of resistance to chemotherapeutic agents remains a pivotal impediment to both prognosis and treatment. Through a single-cell level investigation, we scrutinize the drug resistance and mitotic activity of the core tumor cells in ovarian cancer. Our study revisits the interrelationships and temporal trajectories of distinct epithelial cells (EPCs) subpopulations, while identifying genes associated with ovarian cancer prognosis. Notably, our findings establish a strong association between the drug resistance of EPCs and oxidative phosphorylation pathways. Subsequently, through subpopulation and temporal trajectory analysis, we confirm the intermediate position of EPCs subpopulation C0. Furthermore, we delve into the immunological functions and differentially expressed genes associated with the prognosis of C0, shedding light on the potential for constructing novel ovarian cancer prognosis models and identifying new therapeutic targets.

Application in Gene Editing in Ovarian Cancer Therapy

The onset and progression of ovarian cancer (OC) are closely related to dysregulated gene expression. Current treatments for OC are mainly limited to surgery and chemotherapy. However, due to low drug sensitivity, the prognosis OC is exceptionally poor and the recurrence rate remains high. Hence, it is vital to develop new treatment strategies. Gene editing for site-specific genomic modification is a powerful novel tool for the treatment of OC. In this article, current gene editing research for the treatment of OC is reviewed to provide a reference for the clinical application of new approaches to improve treatment outcomes and prognosis.

Role of the IL-33/ST2 receptor axis in ovarian cancer progression

Ovarian cancer remains a significant health problem for women in the world due to its diagnosis at advanced stages of disease and the high mortality rate of patients. To date, ovarian cancer is frequently treated with tumor reduction surgery followed by platinum/paclitaxel-based chemotherapy; however, most patients eventually develop relapsed disease. The mRNA expression levels of interleukin-33 (IL-33) and the suppressor of tumorigenicity 2 (ST2) receptor are significantly upregulated in ovarian cancer tissues and metastatic tumor lesions. In addition, IL-33 and ST2 expression has been associated with a poor overall survival in patients with epithelial ovarian cancer. The IL-33 receptor ST2 is expressed as both a membrane-anchored receptor (ST2L) activated by IL-33, and as a soluble variant that exhibits anti-inflammatory properties. In the present review, the functions of the IL-33/ST2L axis in cells and their aberrant expression levels in ovarian cancer were discussed. In addition, targeting their expression as a novel strategy for the control of ovarian cancer progression was emphasized.

Advanced clinical trials of dendritic cell vaccines in ovarian cancer

Epithelial ovarian cancer (EOC) is the most common and leading cause of death for gynecologic cancer in the western world. Current standard treatments with limited selection of chemotherapies cannot meet patients' urgent needs. Immunotherapies have recently demonstrated clinical benefits in a variety of solid tumors and may offer a promising frontier for treating EOC. Dendritic cells (DCs) are key coordinators of the innate and adaptive immune system in induction of antitumor immunity. DC-based vaccinations showed clinical benefits and encouraging safety profiles in a few phase II clinical trials for patients with EOC and currently are in a phase III double-blind, randomized, placebo-controlled clinical trial. In this review, we have searched Pubmed and Clinicaltrials. gov databases for past and current phase II or phase III clinical trials with focus on EOC and DC vaccines. Outcomes and implications of the completed and ongoing trials are discussed.

Immune Checkpoint Inhibitors in Epithelial Ovarian Cancer: An Overview on Efficacy and Future Perspectives

Epithelial ovarian cancer (EOC) is the leading cause of death among gynecological cancers. Despite improvements in medical treatments, the prognosis for EOC remains poor, and there is an urgent need for new therapeutic strategies. Immune checkpoint inhibitors (CPIs) have dramatically improved survival of several cancers and are under evaluation in OC. Unfortunately, CPIs have shown globally unsatisfactory results. The aim of this manuscript is to critically review the results from early-phase trials with CPIs in terms of safety and activity, discuss the possible reasons for disappointing results and the new therapeutic approaches to improve patient outcomes.

Organoid of ovarian cancer: genomic analysis and drug screening

Ovarian cancer is the most common malignant tumors of the female reproductive system, and its standard treatments are cytoreductive surgery and platinum-based adjuvant chemotherapy. Great advances have been achieved in novel treatment strategies, including targeted therapy and immunotherapy. However, ovarian cancer has the highest mortality rate among gynecological tumors due to therapeutic resistance and the gap between preclinical data and actual clinical efficacy. Organoids are a 3D culture model that markedly affects gene analysis, drug screening, and drug sensitivity determination of tumors, especially when used in targeted therapy and immunotherapy. In addition, organoid can lead to advances in the preclinical research of ovarian cancer due to its convenient cultivation, good genetic stability, and high homology with primary tumors.

Programmed cell death ligand 1 disruption by clustered regularly interspaced short palindromic repeats/Cas9-genome editing promotes antitumor immunity and suppresses ovarian cancer progression

Programmed cell death ligand 1 (PD‐L1) on tumor cells suppresses anti‐tumor immunity and has an unfavorable prognostic impact in ovarian cancer patients. We herein report the pathophysiological and therapeutic impacts of PD‐L1 disruption in ovarian cancer. PD‐L1 was genetically disrupted in the murine ovarian cancer cell line ID8 using clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9‐mediated genome editing. PD‐L1 knockout (KO) and control ovarian cancer cells were intraperitoneally inoculated into syngeneic mice, and survival and tumor dissemination were evaluated. Survival times were significantly longer in the PD‐L1‐KO ID8‐inoculated groups than in their control groups, and its therapeutic benefit was enhanced in combination with the cisplatin treatment. Tumor weights and ascites volumes were significantly lower in the PD‐L1‐KO ID8 groups than in their control groups. Immunohistochemical and immunofluorescence analyses showed that intratumoral CD4⁺ T cells, CD8⁺ T cells, NK cells and CD11c⁺ M1 macrophages were significantly increased, whereas regulatory T cells were significantly decreased in the PD‐L1‐KO ID8 groups compared with those in their control groups. The intratumoral mRNA expression of interferon‐γ, tumor‐necrosis factor‐α, interleukin (IL)‐2, IL‐12a, CXCL9 and CXCL10 was significantly stronger, while that of IL‐10, vascular endothelial growth factor, CXCL1 and CXCL2 was significantly weaker in the PD‐L1‐KO ID8 groups. These results indicate that CRISPR/Cas9‐mediated PD‐L1 disruption on tumor cells promotes anti‐tumor immunity by increasing tumor‐infiltrating lymphocytes and modulating cytokine/chemokine profiles within the tumor microenvironment, thereby suppressing ovarian cancer progression. These results suggest that PD‐L1‐targeted therapy by genome editing may be a novel therapeutic strategy for ovarian cancer.

Antigen-specific active immunotherapy for ovarian cancer

BACKGROUND

This is the second update of the review first published in the Cochrane Library (2010, Issue 2) and later updated (2014, Issue 9).Despite advances in chemotherapy, the prognosis of ovarian cancer remains poor. Antigen-specific active immunotherapy aims to induce tumour antigen-specific anti-tumour immune responses as an alternative treatment for ovarian cancer.

OBJECTIVES

Primary objective• To assess the clinical efficacy of antigen-specific active immunotherapy for the treatment of ovarian cancer as evaluated by tumour response measured by Response Evaluation Criteria In Solid Tumors (RECIST) and/or cancer antigen (CA)-125 levels, response to post-immunotherapy treatment, and survival differences◦ In addition, we recorded the numbers of observed antigen-specific humoral and cellular responsesSecondary objective• To establish which combinations of immunotherapeutic strategies with tumour antigens provide the best immunological and clinical results SEARCH METHODS: For the previous version of this review, we performed a systematic search of the Cochrane Central Register of Controlled Trials (CENTRAL; 2009, Issue 3), in the Cochrane Library, the Cochrane Gynaecological Cancer Group Specialised Register, MEDLINE and Embase databases, and clinicaltrials.gov (1966 to July 2009). We also conducted handsearches of the proceedings of relevant annual meetings (1996 to July 2009).For the first update of this review, we extended the searches to October 2013, and for this update, we extended the searches to July 2017.

SELECTION CRITERIA

We searched for randomised controlled trials (RCTs), as well as non-randomised studies (NRSs), that included participants with epithelial ovarian cancer, irrespective of disease stage, who were treated with antigen-specific active immunotherapy, irrespective of type of vaccine, antigen used, adjuvant used, route of vaccination, treatment schedule, and reported clinical or immunological outcomes.

DATA COLLECTION AND ANALYSIS

Two reviews authors independently extracted the data. We evaluated the risk of bias for RCTs according to standard methodological procedures expected by Cochrane, and for NRSs by using a selection of quality domains deemed best applicable to the NRS.

MAIN RESULTS

We included 67 studies (representing 3632 women with epithelial ovarian cancer). The most striking observations of this review address the lack of uniformity in conduct and reporting of early-phase immunotherapy studies. Response definitions show substantial variation between trials, which makes comparison of trial results unreliable. Information on adverse events is frequently limited. Furthermore, reports of both RCTs and NRSs frequently lack the relevant information necessary for risk of bias assessment. Therefore, we cannot rule out serious biases in most of the included trials. However, selection, attrition, and selective reporting biases are likely to have affected the studies included in this review. GRADE ratings were high only for survival; for other primary outcomes, GRADE ratings were very low.The largest body of evidence is currently available for CA-125-targeted antibody therapy (17 studies, 2347 participants; very low-certainty evidence). Non-randomised studies of CA-125-targeted antibody therapy suggest improved survival among humoral and/or cellular responders, with only moderate adverse events. However, four large randomised placebo-controlled trials did not show any clinical benefit, despite induction of immune responses in approximately 60% of participants. Time to relapse with CA-125 monoclonal antibody versus placebo, respectively, ranged from 10.3 to 18.9 months versus 10.3 to 13 months (six RCTs, 1882 participants; high-certainty evidence). Only one RCT provided data on overall survival, reporting rates of 80% in both treatment and placebo groups (three RCTs, 1062 participants; high-certainty evidence). Other small studies targeting many different tumour antigens have presented promising immunological results. As these strategies have not yet been tested in RCTs, no reliable inferences about clinical efficacy can be made. Given the promising immunological results and the limited side effects and toxicity reported, exploration of clinical efficacy in large well-designed RCTs may be worthwhile.

AUTHORS' CONCLUSIONS

We conclude that despite promising immunological responses, no clinically effective antigen-specific active immunotherapy is yet available for ovarian cancer. Results should be interpreted cautiously, as review authors found a significant dearth of relevant information for assessment of risk of bias in both RCTs and NRSs.

Genomics of Peritoneal Malignancies

The peritoneum protects the intraabdominal organs. This function is exploited by aggressive cancers originating from organs within the abdomen, resulting in peritoneal metastasis. We discuss genomic variants that may lead to peritoneal metastasis from multiple cancers. Peritoneal malignancies are attributed to epithelial-mesenchymal transition. These metastatic lesions harbor similar genetic mutations to the primary tumor yet may manifest clone-specific aberrations that promote propagation. Peritoneal metastasis are increasingly being treated with surgical resection as an adjunct to radiation, chemotherapy, and other biologic therapies. We describe genetic and genomic variances that are predictive markers for metastasis and burgeoning indicators for peritoneal malignancies.

Ancient and modern: hints of a core post-transcriptional network driving chemotherapy resistance in ovarian cancer

RNA-binding proteins (RBPs) and noncoding (nc)RNAs (such as microRNAs, long ncRNAs, and others) cooperate within a post-transcriptional network to regulate the expression of genes required for many aspects of cancer behavior including its sensitivity to chemotherapy. Here, using an RBP-centric approach, we explore the current knowledge surrounding contributers to post-transcriptional gene regulation (PTGR) in ovarian cancer and identify commonalities that hint at the existence of an evolutionarily conserved core PTGR network. This network regulates survival and chemotherapy resistance in the contemporary context of the cancer cell. There is emerging evidence that cancers become dependent on PTGR factors for their survival. Further understanding of this network may identify innovative therapeutic targets as well as yield crucial insights into the hard-wiring of many malignancies, including ovarian cancer. WIREs RNA 2018, 9:e1432. doi: 10.1002/wrna.1432 This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Translation > Translation Mechanisms RNA in Disease and Development > RNA in Disease.