Price, J. S. | Search bioRxiv

bioRxiv2025

Autocrine TGFβ2 enforces a transcriptionally hybrid cell state in Ewing sarcoma

Sub-populations of cancer-associated fibroblast (CAF)-like tumor cells deposit extracellular matrix (ECM) proteins that support Ewing sarcoma (EwS) progression and metastasis. We previously showed a hallmark of CAF-like EwS cells is their hybrid transcriptional state wherein the driver fusion oncogene, EWS::FLI1, maintains activation of proliferative programs but loses capacity to repress mesenchymal genes. Here, we studied primary patient tumors and cell line models to identify molecular drivers of this hybrid state. Our data reveal that hybrid EwS cells are induced and maintained by a TGF{beta} signaling positive feedback loop. Hybrid cells de-repress TGFBR2 and upregulate expression and secretion of TGF{beta}2 to sustain pathway activation and ECM deposition. While TGF{beta} ligands can potently induce growth arrest in cells of epithelial origin, we show that TGF{beta}1 and TGF{beta}2 promote cell invasion of EwS cells without affecting proliferation. Thus, stroma and tumor-derived TGF{beta} ligands induce and maintain hybrid EwS cells to promote pro-metastatic cell phenotypes.

cancer biology↗

bioRxiv2019

Cortical bone gain following loading is site-specifically enhanced by prior and concurrent disuse in aged male mice

The primary aim of bone anabolic therapies is to strategically increase bone mass in skeletal regions likely to experience high strains. This is naturally achieved by mechanical loading of the young healthy skeleton. However, these bone anabolic responses fail with age. Here, we applied site specificity analysis to map regional differences in bone anabolic responses to axial loading of the tibia (tri-weekly, for two weeks) between young (19-week-old) and aged (19-month-old), male and female mice. Loading increased bone mass specifically in the proximal tibia in both sexes and ages. Young female mice gained more cortical bone than young males in specific regions of the tibia. However, these site-specific sex difference were lost with age such that bone gain following loading was not significantly different between old males and females. Having previously demonstrated that prior and concurrent disuse enhances bone gain following loading in old females, we established whether this \"rescue\" is sex-specific. Old male mice were subjected to sciatic neurectomy or sham surgery, and tri-weekly loading was initiated four days after surgery. Disuse augmented cortical bone gain in response to loading in old male mice, but only in the regions of the tibia which were load-responsive in the young. Increased understanding of how locally-activated load-responsive processes lead to site-specific bone formation, and how the age-related diminution of these processes can be site-specifically enhanced by disuse, may lead to the next generation of strategic bone anabolic therapies.\n\nHighlightsO_LISex differences in cortical tissue area of young and old mice are not site-specific\nC_LIO_LIThe loading response in young, but not old, mice is sex- and site-specific\nC_LIO_LIThe cortical loading response is site-specifically enhanced by disuse in old mice of both sexes\nC_LIO_LIThe trabecular loading response can be rescued by disuse in old male, but not female, mice\nC_LI

physiology↗