Spheroid Formation and Peritoneal Metastasis in Ovarian Cancer: The Role of Stromal and Immune Components

Targeting interleukin-6 as a treatment approach for peritoneal carcinomatosis

Peritoneal carcinomatosis (PC) is a complex manifestation of abdominal cancers, with a poor prognosis and limited treatment options. Recent work identifying high concentrations of the cytokine interleukin-6 (IL-6) and its soluble receptor (sIL-6-Rα) in the peritoneal cavity of patients with PC has highlighted this pathway as an emerging potential therapeutic target. This review article provides a comprehensive overview of the current understanding of the potential role of IL-6 in the development and progression of PC. We discuss mechansims by which the IL-6 pathway may contribute to peritoneal tumor dissemination, mesothelial adhesion and invasion, stromal invasion and proliferation, and immune response modulation. Finally, we review the prospects for targeting the IL-6 pathway in the treatment of PC, focusing on common sites of origin, including ovarian, gastric, pancreatic, colorectal and appendiceal cancer, and mesothelioma.

Immunotherapy and the ovarian cancer microenvironment: Exploring potential strategies for enhanced treatment efficacy

Despite progress in cancer immunotherapy, ovarian cancer (OC) prognosis continues to be disappointing. Recent studies have shed light on how not just tumour cells, but also the complex tumour microenvironment, contribute to this unfavourable outcome of OC immunotherapy. The complexities of the immune microenvironment categorize OC as a 'cold tumour'. Nonetheless, understanding the precise mechanisms through which the microenvironment influences the effectiveness of OC immunotherapy remains an ongoing scientific endeavour. This review primarily aims to dissect the inherent characteristics and behaviours of diverse cells within the immune microenvironment, along with an exploration into its reprogramming and metabolic changes. It is expected that these insights will elucidate the operational dynamics of the immune microenvironment in OC and lay a theoretical groundwork for improving the efficacy of immunotherapy in OC management.

Proteomic analysis of ascitic extracellular vesicles describes tumour microenvironment and predicts patient survival in ovarian cancer

High-grade serous carcinoma of the ovary, fallopian tube and peritoneum (HGSC), the most common type of ovarian cancer, ranks among the deadliest malignancies. Many HGSC patients have excess fluid in the peritoneum called ascites. Ascites is a tumour microenvironment (TME) containing various cells, proteins and extracellular vesicles (EVs). We isolated EVs from patients' ascites by orthogonal methods and analyzed them by mass spectrometry. We identified not only a set of 'core ascitic EV-associated proteins' but also defined their subset unique to HGSC ascites. Using single-cell RNA sequencing data, we mapped the origin of HGSC-specific EVs to different types of cells present in ascites. Surprisingly, EVs did not come predominantly from tumour cells but from non-malignant cell types such as macrophages and fibroblasts. Flow cytometry of ascitic cells in combination with analysis of EV protein composition in matched samples showed that analysis of cell type-specific EV markers in HGSC has more substantial prognostic potential than analysis of ascitic cells. To conclude, we provide evidence that proteomic analysis of EVs can define the cellular composition of HGSC TME. This finding opens numerous avenues both for a better understanding of EV's role in tumour promotion/prevention and for improved HGSC diagnostics.

Progress in the treatment of malignant ascites

Malignant ascites occurs as a symptom of the terminal stage of cancer, affecting the quality of life through abdominal distension, pain, nausea, anorexia, dyspnea and other symptoms. We describe the current main drug treatments in addition to surgery according to the traditional and new strategies. Traditional treatments were based on anti-tumor chemotherapy and traditional Chinese medicine treatments, as well as diuretics to relieve the patient's symptoms. New treatments mainly involve photothermal therapy, intestinal therapy and targeted immunity. This study emphasizes that both traditional and new therapies have certain advantages and disadvantages, and medication should be adjusted according to different periods of use and different patients. In conclusion, this article reviews the literature to systematically describe the primary treatment modalities for malignant ascites.

Advances in the treatment of malignant ascites in China

PURPOSE

Malignant ascites (MA) often occurs in recurrent abdominal malignant tumors, and the large amount of ascites associated with cancerous peritonitis not only leads to severe abdominal distension and breathing difficulties, but also reduces the patient's quality of life and ability to resist diseases, which usually makes it difficult to carry out anti-cancer treatment. The exploration of MA treatment methods is also a key link in MA treatment. This article is going to review the treatment of MA, to provide details for further research on the treatment of MA, and to provide some guidance for the clinical treatment of MA.

METHOD

This review analyzes various expert papers and summarizes them to obtain the paper.

RESULT

There are various treatment methods for MA, including systemic therapy and local therapy. Among them, systemic therapy includes diuretic therapy, chemotherapy, immunotherapy, targeted therapy, anti angiogenic therapy, CAR-T, and vaccine. Local therapy includes puncture surgery, peritoneal vein shunt surgery, acellular ascites infusion therapy, radioactive nuclide intraperitoneal injection therapy, tunnel catheter, and intraperitoneal hyperthermia chemotherapy. And traditional Chinese medicine treatment has also played a role in enhancing efficacy and reducing toxicity to a certain extent.

CONCLUSION

Although there has been significant progress in the treatment of MA, it is still one of the clinical difficulties. Exploring the combination or method of drugs with the best therapeutic effect and the least adverse reactions to control MA is still an urgent problem to be solved.

Limitations and potential of immunotherapy in ovarian cancer

Ovarian cancer (OC) is the third most common gynecological cancer and alone has an emergence rate of approximately 308,069 cases worldwide (2020) with dire survival rates. To put it into perspective, the mortality rate of OC is three times higher than that of breast cancer and it is predicted to only increase significantly by 2040. The primary reasons for such a high rate are that the physical symptoms of OC are detectable only during the advanced phase of the disease when resistance to chemotherapies is high and around 80% of the patients that do indeed respond to chemotherapy initially, show a poor prognosis subsequently. This highlights a pressing need to develop new and effective therapies to tackle advanced OC to improve prognosis and patient survival. A major advance in this direction is the emergence of combination immunotherapeutic methods to boost CD8+ T cell function to tackle OC. In this perspective, we discuss our view of the current state of some of the combination immunotherapies in the treatment of advanced OC, their limitations, and potential approaches toward a safer and more effective response.

Iron affects the sphere-forming ability of ovarian cancer cells in non-adherent culture conditions

Introduction: Detachment from the extracellular matrix (ECM) is the first step of the metastatic cascade. It is a regulated process involving interaction between tumor cells and tumor microenvironment (TME). Iron is a key micronutrient within the TME. Here, we explored the role of iron in the ability of ovarian cancer cells to successfully detach from the ECM. Methods: HEY and PEO1 ovarian cancer cells were grown in 3D conditions. To mimic an iron rich TME, culture media were supplemented with 100 μM Fe3+. Cell mortality was evaluated by cytofluorimetric assay. The invasive potential of tumor spheroids was performed in Matrigel and documented with images and time-lapses. Iron metabolism was assessed by analyzing the expression of CD71 and FtH1, and by quantifying the intracellular labile iron pool (LIP) through Calcein-AM cytofluorimetric assay. Ferroptosis was assessed by quantifying mitochondrial reactive oxygen species (ROS) and lipid peroxidation through MitoSOX and BODIPY-C11 cytofluorimetric assays, respectively. Ferroptosis markers GPX4 and VDAC2 were measured by Western blot. FtH1 knockdown was performed by using siRNA. Results: To generate spheroids, HEY and PEO1 cells prevent LIP accumulation by upregulating FtH1. 3D HEY moderately increases FtH1, and LIP is only slightly reduced. 3D PEO1upregulate FtH1 and LIP results significantly diminished. HEY tumor spheroids prevent iron import downregulating CD71, while PEO1 cells strongly enhance it. Intracellular ROS drop down during the 2D to 3D transition in both cell lines, but more significantly in PEO1 cells. Upon iron supplementation, PEO1 cells continue to enhance CD71 and FtH1 without accumulating the LIP and ROS and do not undergo ferroptosis. HEY, instead, accumulate LIP, undergo ferroptosis and attenuate their sphere-forming ability and invasiveness. FtH1 knockdown significantly reduces the generation of PEO1 tumor spheroids, although without sensitizing them to ferroptosis. Discussion: Iron metabolism reprogramming is a key event in the tumor spheroid generation of ovarian cancer cells. An iron-rich environment impairs the sphere-forming ability and causes cell death only in ferroptosis sensitive cells. A better understanding of ferroptosis sensitivity could be useful to develop effective treatments to kill ECM-detached ovarian cancer cells.

Normal Uterine Fibroblast Are Reprogramed into Ovarian Cancer-Associated Fibroblasts by Ovarian Tumor-derived Conditioned Media

Cancer-associated fibroblasts (CAFs) are key contributors to ovarian cancer (OC) progression and therapeutic resistance through dysregulation of the extracellular matrix (ECM). CAFs are a heterogenous population derived from different cell types through activation and reprogramming. Current studies rely on uncharacterized heterogenous primary CAFs or normal fibroblasts that fail to recapitulate CAF-like tumor behavior. Here, we present a translatable-based approach for the reprogramming of normal uterine fibroblasts into ovarian CAFs using ovarian tumor-derived conditioned media to establish two well-characterized ovarian conditioned CAF lines. Phenotypic and functional characterization demonstrated that the conditioned CAFs expressed a CAF-like phenotype, strengthened proliferation, secretory, contractility, and ECM remodeling properties when compared to resting normal fibroblasts, consistent with an activated fibroblast status. Moreover, conditioned CAFs significantly enhanced drug resistance and tumor progression and resembled a CAF-like subtype associated with worse prognosis. The present study provides a reproducible, cost-effective, and clinically relevant protocol to reprogram normal fibroblasts into CAFs using tumor-derived conditioned media. Using these resources, further development of therapeutics that possess potentiality and specificity towards CAF-mediated chemoresistance in OC are further warranted.

IGF2BP2 promotes ovarian cancer growth and metastasis by upregulating CKAP2L protein expression in an m6 A-dependent manner

Ovarian cancer (OC) is the second leading cause of gynecological cancer-related death in women worldwide. N6-methyladenosine (m6 A) is the most abundant internal modification in eukaryotic RNA. Human insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2), an m6 A reader, can enhance mRNA stability and promote translation by recognizing m6 A modifications. Its tumor-promoting effects have been demonstrated in several cancers. However, the roles of m6 A modification and IGF2BP2 in OC remain unclear. Here, by using methylated RNA immunoprecipitation sequencing, we demonstrated that there is widespread dysregulation of m6 A modification in OC tissues. The m6 A modification and the mRNA and protein levels of IGF2BP2 were significantly elevated in OC. Overexpression of IGF2BP2 facilitated OC cell proliferation, migration, and invasion in vitro and accelerated tumor growth and metastasis in vivo. While IGF2BP2-knockdown showed the opposite effect. Mechanistically, we identified cytoskeleton-associated protein 2-like (CKAP2L) as a target of IGF2BP2. IGF2BP2 promoted CKAP2L translation dependent on m6 A modification, rather than affecting mRNA and protein stability. Overexpression of CKAP2L rescued the tumor-suppressive effect of IGF2BP2 knockdown in OC cells. In conclusion, this study revealed the potential role of IGF2BP2 in tumor progression, at least partially via promoting the translation of CKAP2L in an m6 A-dependent manner.

Morphological and Immunocytochemical Characterization of Tumor Spheroids in Ascites from High-Grade Serous Carcinoma

Tumor spheroids in the ascites of high-grade serous carcinoma (HGSC) are poorly described. Our objective was to describe their morphological features, cellular composition, PD-1 and PD-L1 expression, and survival correlation of these parameters. The density and size of spheroids were assessed in Giemsa-stained smears; the cell composition of spheroids, including tumor cells, immune cells, capillaries, and myofibroblasts, as well as PD-1 and PD-L1 expression on tumor and immune cells was assessed in immunocytochemically stained cell block sections. Forty-seven patients with primary HGSC and malignant ascites were included. A cut-off value for a spheroid density of 10% was established, which significantly predicted overall survival. However, spheroid size did not correlate with survival outcomes. Spheroids were primarily composed of tumor cells, but the presence of lymphocytes and macrophages was also confirmed. Moreover, capillaries were present in the spheroids of three patients, but the presence of myofibroblasts was not confirmed. PD-1 was expressed on lymphocytes but not on tumor cells. PD-L1 expression was seen on both tumor and immune cells, assessed by 22C3 and SP263 antibody clones but not by the SP142 clone. Our results highlight the potential of routine cytopathological techniques to analyze spheroids in HGSC ascites as a valuable tool to investigate their potential as prognostic markers.

Identification of necroptosis subtypes and development of necroptosis-related risk score model for in ovarian cancer

Background: ith the ongoing development of targeted therapy, non-apoptotic cell death, including necroptosis, has become a popular topic in the field of prevention and treatment. The purpose of this study was to explore the effect of necroptosis-related genes (NRGs) on the classification of ovarian cancer (OV) subtypes and to develop a necroptosis-related risk score (NRRS) classification system. Methods: 74 NRGs were obtained from the published studies, and univariate COX regression analysis was carried out between them and OV survival. Consensus clustering analysis was performed on OV samples according to the expression of NRGs related to prognosis. Furthermore, the NRRS model was developed by combining Weighted Gene Co-Expression Network Analysis (WGCNA) with least absolute shrinkage and selection operator (Lasso)-penalized Cox regression and multivariate Cox regression analysis. And the decision tree model was constructed based on the principle of random forest screening factors principle. Results: According to the post-related NRGs, OV was divided into two necroptosis subtypes. Compared with Cluster 1 (C1), the overall survival (OS) of Cluster 2 (C2) was significantly shorter, stromal score and immune score, the infiltration level of tumor associated immune cells and the expression of 20 immune checkpoints were significantly higher. WGCNA identified the blue module most related to necroptosis subtype, and 12 genes in the module were used to construct NRRS. NRRS was an independent prognostic variable of OV. The OS of samples with lower NRRS was significantly longer, and tumor mutation burden and homologous recombination defect were more obvious. Conclusion: This study showed that necroptosis plays an important role in the classification, prognosis, immune infiltration and biological characteristics of OV subtypes. The evaluation of tumor necroptosis may provide a new perspective for OV treatment.

New Insights into Ferroptosis Initiating Therapies (FIT) by Targeting the Rewired Lipid Metabolism in Ovarian Cancer Peritoneal Metastases

Ovarian cancer is one of the most lethal gynecological cancers worldwide. The poor prognosis of this malignancy is substantially attributed to the inadequate symptomatic biomarkers for early diagnosis and effective remedies to cure the disease against chemoresistance and metastasis. Ovarian cancer metastasis is often relatively passive, and the single clusters of ovarian cancer cells detached from the primary ovarian tumor are transcoelomic spread by the peritoneal fluid throughout the peritoneum cavity and omentum. Our earlier studies revealed that lipid-enriched ascitic/omental microenvironment enforced metastatic ovarian cancer cells to undertake metabolic reprogramming and utilize free fatty acids as the main energy source for tumor progression and aggression. Intriguingly, cell susceptibility to ferroptosis has been tightly correlated with the dysregulated fatty acid metabolism (FAM), and enhanced iron uptake as the prominent features of ferroptosis are attributed to the strengthened lipid peroxidation and aberrant iron accumulation, suggesting that ferroptosis induction is a targetable vulnerability to prevent cancer metastasis. Therefore, the standpoints about tackling altered FAM in combination with ferroptosis initiation as a dual-targeted therapy against advanced ovarian cancer were highlighted herein. Furthermore, a discussion on the prospect and challenge of inducing ferroptosis as an innovative therapeutic approach for reversing remedial resistance in cancer interventions was included. It is hoped this proof-of-concept review will indicate appropriate directions for speeding up the translational application of ferroptosis-inducing compounds (FINs) to improve the efficacy of ovarian cancer treatment.