Gultekin, O. | bioRxiv Science

bioRxiv2022

YAP and collagen remodelling support cell proliferation and tumour aggressiveness in uterine leiomyosarcoma

Fibrillar collagen deposition, stiffness, and downstream signalling support the development of leiomyomas (LM), common benign mesenchymal tumours of the uterus, and are associated with aggressiveness in multiple carcinomas. Compared to epithelial carcinomas, however, the impact of fibrillar collagens on malignant mesenchymal tumours, including uterine leiomyosarcoma (LMS), remains elusive. In this study, we analyse the network morphology and density of fibrillar collagens combined with the gene expression of LMS, LM and normal myometrium (MM). We find that, in contrast to LM, LMS tumours present low collagen density and increased expression of collagen-remodelling genes, features associated with tumour aggressiveness. Using collagen-based 3D matrices, we show that the activity of MMP14, a central protein with collagen-remodelling functions particularly overexpressed in LMS, is necessary for LMS cell proliferation. In addition, we find that, unlike MM and LM cells, LMS proliferation and migration are not affected by collagen substrate stiffness. We demonstrate that LMS cell growth in low matrix adhesion microenvironments is supported by an enhanced basal YAP activity. Altogether, our results indicate that LMS cells acquire high collagen remodelling capabilities and are adapted to grow and migrate in low collagen and soft microenvironments. These results further suggest that matrix remodelling and YAP are potential therapeutic targets for this deadly disease.

cancer biology↗

bioRxiv2021

Regulatory FOXP3+ T cells in uterine sarcomas are associated with favorable prognosis, low extracellular matrix expression and reduced YAP activation

PurposeUterine sarcomas are rare but deadly malignancies without effective treatment. The goal of this study was to characterize and identify potential mechanisms underlying observed variations in the immune microenvironment of different sarcoma subtypes, using integrated clinicopathological and molecular methods. Experimental designFifty-eight cases of uterine sarcoma with full clinicopathological annotation were analyzed for their immune landscape in the tumor microenvironment, gene, and protein expression. Cases included leiomyosarcoma (LMS; n=13), low-grade endometrial stromal sarcoma (ESS; n=16), undifferentiated uterine sarcoma (UUS; n=26), and YWHAE-FAM22 translocation-bearing ESS (YFAM; n=3). Image analysis was used to quantify immune cells and immune regulatory proteins. Gene ontology and network enrichment analysis of matching transcriptomic data was used to relate over- and under expressed genes to pathways and further to the immune phenotype and clinicopathological findings. ResultsImmune cell characterization revealed overall prevalence of regulatory T cells and the pro-tumor M2-like macrophages. Cytotoxic T cells were only found in ESS and UUS tumors. Expression of immune regulatory proteins was heterogeneous, with PD-L1 being undetectable. Hierarchical clustering of patients showed four immune signatures independent of tumor type, where infiltration of non-exhausted FOXP3+ cells and M1-like macrophages were associated with greater overall survival. High CD8+/FOXP3+ ratio in UUS and ESS was associated with poor survival and upregulation of extracellular matrix (ECM)-related genes and proteins and YAP nuclear localization. ConclusionsUterine sarcomas present distinct immune signatures with prognostic value, independent of tumor type. This study suggests that the ECM is a potential regulator of the immune microenvironment in uterine sarcomas.

cancer biology↗