Assessment of the immune landscapes of advanced ovarian cancer in an optimized in vivo model

Abstract

Background Ovarian cancer (OC) is typically diagnosed late, associated with high rates of metastasis and the onset of ascites during late stage disease. Understanding the tumor microenvironment and how it impacts the efficacy of current treatments, including immunotherapies, needs effective in vivo models that are fully characterized. In particular, understanding the role of immune cells within the tumor and ascitic fluid could provide important insights into why OC fails to respond to immunotherapies. In this work, we comprehensively described the immune cell infiltrates in tumor nodules and the ascitic fluid within an optimized preclinical model of advanced ovarian cancer. Methods Green Fluorescent Protein (GFP)‐ID8 OC cells were injected intraperitoneally into C57BL/6 mice and the development of advanced stage OC monitored. Nine weeks after tumor injection, mice were sacrificed and tumor nodules analyzed to identify specific immune infiltrates by immunohistochemistry. Ascites, developed in tumor bearing mice over a 10‐week period, was characterized by mass cytometry (CyTOF) to qualitatively and quantitatively assess the distribution of the immune cell subsets, and their relationship to ascites from ovarian cancer patients. Results Tumor nodules in the peritoneal cavity proved to be enriched in T cells, antigen presenting cells and macrophages, demonstrating an active immune environment and cell‐mediated immunity. Assessment of the immune landscape in the ascites showed the predominance of CD8 + , CD4 + , B – , and memory T cells, among others, and the coexistance of different immune cell types within the same tumor microenvironment. Conclusions We performed, for the first time, a multiparametric analysis of the ascitic fluid and specifically identify immune cell populations in the peritoneal cavity of mice with advanced OC. Data obtained highlights the impact of CytOF as a diagnostic tool for this malignancy, with the opportunity to concomitantly identify novel targets, and define personalized therapeutic options.

Paracrine CSF1 signaling regulates macrophage migration dynamics towards ovarian cancer cells in a 3D microfluidic model that recapitulates in vivo infiltration patterns in patient-derived xenograft models

“…These results are similar to migration indices observed in transwell coculture assays with ovarian cancer cells and macrophages [14]. Furthermore, previous in vivo studies have shown that ID8 tumor models can be characterized by enrichment of macrophages in tumor nodules [15]. The recruitment of macrophages by ovarian cancer cells in our model is therefore reflective of previous in vivo and in vitro studies.…”

“…ID8 is a well-characterized model of ovarian cancer that was derived from C57/BL/6 ovarian epithelium. Specifically, ID8 is an aggressive model that establishes in vivo microenvironments that are infiltrated by macrophages [15]. Without tumor cells, the presence of macrophages within the gel region was 56 ± 6 x 10 -5 cells/px 2 .…”

Transcriptomic analysis reveals the anti-cancer effect of gestational mesenchymal stem cell secretome

“…While 3D culture systems are gaining momentum in the development of cancer therapeutics 66 preclinical studies would provide evidence of the anti-cancer potential of AF- and CV-MSCs (and their secretome) in a system that more closely recapitulates the complexity of the tumor microenvironment. We anticipate, however, that building on this work, future studies evaluating the anti-cancer potential of the secretome of AF- and CV-MSCs will be performed in mouse models of syngeneic ovarian cancer optimized in the lab 67 to provide additional insights on the biological effect in complex systems. Finally, moving forward, we are committed to providing a comprehensive characterization (in terms of proteomic, lipidomic, and transcriptomic profile) of the exosomes released by AF- and CV-MSCs, to identify specific targeting moieties as well as master regulators of the cytotoxic and inhibitory effect observed.…”

Establishment of highly metastatic ovarian cancer model with omental tropism via in vivo selection

“…Indeed, metastasis is rarely observed in most subcutaneous mouse models, including OC. 12 , 13 The in vivo metastatic OC models currently used mainly refer to the intraperitoneal 14 and orthotopic models. 15 The intraperitoneal model is able to recapitulate the implantation metastasis of OC at advanced stages, but it is generated without primary tumor growth.…”