Fabian Coscia

Spatial proteomics of ovarian cancer precursors delineates early disease changes and drug targets

Abstract High-grade serous ovarian cancer (HGSOC) is often detected at an advanced stage, where curative treatment options are limited. Recent advances in ultrasensitive mass spectrometry-based spatial proteomics have provided a unique opportunity to uncover molecular drivers of early tumorigenesis and novel therapeutic targets. Here, we present a comprehensive proteomic analysis of serous tubal intraepithelial carcinoma (STIC), the HGSOC precursor lesion, and concurrent invasive carcinoma, covering more than 10,000 proteins from ultra-low input archival tissue. STIC and HGSOC showed highly similar proteomes, clustering into two subtypes with distinct tumor-immune microenvironments and common remodeling of the extracellular matrix. We discovered cell-of-origin signatures from secretory fallopian tube epithelial cells in STICs and identified early dysregulated pathways of therapeutic relevance. Targeting cholesterol biosynthesis by inhibiting the terminal steps via DHCR7 showed therapeutic effects in ovarian cancer cell lines and synergized with standard-of-care carboplatin treatment. This study demonstrates the power of spatially resolved quantitative proteomics in understanding early carcinogenesis and provides a rich resource for biomarker and drug target research.

A Proteogenomic View of Synchronous Endometrioid Endometrial and Ovarian Cancer

Abstract Purpose: Increasing genomics-based evidence suggests that synchronous endometrial and ovarian cancer (SEOC) represents clonally related primary and metastatic tumors. A systematic analysis of the global protein landscape of SEOCs, heretofore lacking, could reveal functional and disease-specific consequences of known genetic alterations, the directionality of metastasis, and accurate histologic markers to distinguish SEOCs from single-site tumors. Experimental Design: We performed a systematic proteogenomic analysis of 29 patients diagnosed with SEOC at three international gynecologic oncology treatment centers (Chicago, Vancouver, and Tübingen). For direct comparison with single-site tumors, we included 9 patients with single-site endometrioid ovarian and 26 patients with single-site endometrioid endometrial cancer (EEC). For all 64 patients, we performed sequencing of a 275-gene cancer panel combined with compartment-resolved mass spectrometry–based proteomics of consecutive tissue sections to compare global (6,000+ proteins), tumor, and stromal proteomes. Results: DNA-based panel sequencing confirmed that most SEOCs are clonally related. Global proteome profiling uncovered pronounced differences between SEOCs and single tumors and underscored the importance of the stromal proteome in defining and identifying SEOCs. We identified molecularly unique SEOC stromal proteomes, which were globally more related to single endometrial cancers. We finally derived a proteomic predictor distinguishing SEOCs from single-site ovarian and uterine tumors. Conclusions: The integrated proteogenomic data show that SEOCs are distinguishable from endometrioid endometrial or endometrioid ovarian cancer. Based on their proteogenomic similarity to EECs, we conclude that most SEOCs represent primary EECs that have metastasized to the ovary.