AKT3-Driven Epithelial-Mesenchymal Plasticity Governs Ovarian Metastasis in Colorectal Cancer via Tumor Microenvironment Remodeling.

UNLABELLED: Colorectal ovarian metastasis (CROM), a distinct metastatic subtype of colorectal cancer, is associated with early disease onset and aggressive progression. CROM lacks specific treatment options, highlighting the need to elucidate the underlying biological mechanisms and potential therapeutic vulnerabilities. In this study, we performed integrated analyses of single-cell RNA sequencing (scRNA-seq) datasets from 155,163 cells across 35 patients from the in-house cohort and public datasets, with matched bulk transcriptomic profiling. The analysis identified AKT3+ epithelial-mesenchymal transition (EMT)-like cells at the invasive tumor-stroma interface as metastasis-initiating cells. Functional validation using in vivo xenograft models demonstrated that AKT3 deficiency reduced ovarian colonization, whereas AKT3 overexpression conferred a mesenchymal phenotype with invasive capacity. Furthermore, reciprocal cross-talk between AKT3+ mesenchymal-like cells and cancer-associated fibroblasts (CAF) played a key role in remodeling the tumor microenvironment. Multiplex immunofluorescence staining of primary tumor specimens revealed spatially coordinated AKT3+/SNAIL+/ITGB1+ tumor buds adjacent to αSMA+ CAFs at the invasive front. Critically, AKT3 inhibition or knockdown in patient-derived CROM organoids (CROM-PDO) significantly suppressed malignant phenotypes, recapitulating the AKT3 dependency. Collectively, these findings elucidate an AKT3-driven feedforward loop coupling EMT plasticity with CAF activation as a critical driver of CROM and propose CROM-PDOs as a robust platform for developing precision therapies targeting this aggressive colorectal cancer subtype.

SIGNIFICANCE: Single-cell analyses reveal AKT3-expressing mesenchymal-like cells as drivers of colorectal ovarian metastases, which depends on the dynamic cross-talk between cancer cells and cancer-associated fibroblasts within the immunosuppressive ovarian niche.