Sagar Rayamajhi

Defining the Ovarian Cancer Precancerous Landscape through Modeling Fallopian Tube Epithelium Reprogramming Driven by Extracellular Vesicles

Abstract Serous tubal intraepithelial carcinomas (lesions) in the human fallopian tube epithelium (hFTE) are theorized to give rise to high-grade serous ovarian cancers. Small extracellular vesicles (sEV) are known to mediate key signaling in both normal and cancerous tissues, but few ex vivo systems exist for studying the impact of sEV on hFTE tissue. In this study, we present a microfluidic tissue culture platform with combined spatial transcriptomic and proteomic readouts that allows us to profile dual responses in tissue exposed to sEV “messages”—capturing both short-term transcriptomic shifts in the tissue and long-term changes in protein cargo of secreted EVs (the “reply”). Using spatial transcriptomics, we show that the short-term 1-day exposure to ovarian cancer–derived sEVs alters expression of 68 transcripts in secretory cells, the progenitor of high-grade serous ovarian cancer, notably upregulating immune-related mRNA, including CXCL family chemokines, VCAM1, and pro-inflammatory mediators (NFKB1, IL1B, and IFNA7/17). Additionally, we observed that the long-term 14-day exposure to sEVs alters the expression of seven transcripts and 25 EV cargo proteins of fallopian tube–derived EVs (“secondary release EVs”) following stimulus from cancer EVs. Together, tissue transcriptomics and tissue-derived EV proteomics indicate that ovarian cancer–derived sEVs rewire target cell signaling to modify the tubal immune landscape. This study provides insights into the early molecular changes associated with the pathogenesis of ovarian cancer in its tissue of origin, providing a platform to study EV–tissue interactions and identify how sEVs drive cell signaling reprogramming in hFTE. Significance: We model the fallopian tube preneoplastic landscape using a microfluidic platform to study EV-induced stress and show that cancer EVs promote immune signaling changes representing the earliest stages of ovarian cancer pathogenesis.

Ovarian tumor cells gain competitive advantage by actively reducing the cellular fitness of microenvironment cells

Cell competition and fitness comparison between cancer and tumor microenvironment (TME) cells determine oncogenic fate. Our previous study established a role for human Flower isoforms as fitness fingerprints, where the expression of Flower Win isoforms in tumor cells leads to growth advantage over TME cells expressing Lose isoforms. Here we demonstrate that the expression of Flower Lose and reduced microenvironment fitness is not a pre-existing condition but, rather, a cancer-induced phenomenon. Cancer cells actively reduce TME fitness by the exosome-mediated release of a cancer-specific long non-coding RNA, Tu-Stroma, which controls the splicing of the Flower gene in the TME cells and expression of Flower Lose isoform, which leads to reduced fitness status. This mechanism controls cancer growth, metastasis and host survival in ovarian cancer. Targeting Flower protein with humanized monoclonal antibody (mAb) in mice significantly reduces cancer growth and metastasis and improves survival. Pre-treatment with Flower mAb protects intraperitoneal organs from developing lesions despite the presence of aggressive tumor cells.