Abstract
Ovarian cancer is one of the leading causes of cancer-related mortality among women and remains exceptionally difficult to manage and treat effectively in the clinic. Fragile X-related protein 1 (FXR1) is highly amplified and overexpressed in ovarian and several other cancers. FXR1 is a key regulator of the translation of multiple oncogenes and therefore represents a vulnerable target for cancer therapy. RNA interference (RNAi) of FXR1 using a locked nucleic acid (LNA) form of siRNA (siFXR1-LNA) inhibits tumor growth, ascites formation, and metastasis of ovarian cancer more efficiently than the native form of FXR1 siRNA in vivo. LNA modification of siRNA improves resistance to RNase mediated degradation and enhances tumor tissue uptake of siRNA with robust inhibition of target mRNA in tumor tissues. Single-cell RNA sequencing (scRNA-seq) analysis of ascites composed of tumor, stromal, and immune cells analysis reveals that FXR1 silencing suppresses tumor cell proliferation and reduces tumor-promoting M2-like macrophages. FXR1 silencing also increases cytotoxic T cells, NK cells, and dendritic cells with anti-tumor characteristics in vivo. Collectively, our data establishes FXR1 as an important regulator of oncogenic processes in cancer tissues and serves as a therapeutic liability. Therefore, FXR1 silencing in tumor tissues provides an effective strategy to treat tumors expressing high levels of FXR1.
Data availability
The raw scRNA-seq data generated in this study are available through the Gene Expression Omnibus (GEO) under accession number GSE292799.
The remaining data are available either within the article, Supplementary Information or Source Data file. All source data files are provided with this paper. Source data are provided with this paper.
Code availability
The analysis in this study was performed using standard and publicly available R packages as detailed in the Methods section. No custom codes were developed for any analyses in this study. Therefore, no additional code is available for public sharing.
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Acknowledgements
This work was supported in part by grants to P.C.-R. from DoD W81XWH-21-1-0365, HT9425-23-1-0311, 1R01CA291708-01A1, and Linda G. and Herbert J. Buchsbaum Endowment, Women’s Health Research Program (WHRP) funds, and the Sharon L. La Macchia Innovation Fund at MCW. S.P. was supported by the Department of Defense (DoD W81XWH-21-1-0361 and W81XWH-21-1-0138) and NCI R01CA258433. J.G was partially supported by MCW Cancer Center postdoctoral award. P.C.-R. was also supported by seed funds from MCW Cancer Center and Advancing Healthier Wisconsin Endowment funds. We also thank the animal core facility, and biomedical imaging shared resource core of Medical College of Wisconsin, and the Children’s Research Institute’s histology core. All contributing authors reviewed and provided consent for publication.
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P.C.R. conceived the study, generated hypotheses, designed experiments, and analyzed the results. J.G. conceived the study, designed and performed most of the experiments, including cell cultures, animal experiments, microscopy, immunoblots, statistical analyses, prepared figures, and the draft of the manuscript. X.M., A.N., S-W.T., and C-W. L. performed all the bioinformatics and computational analysis for this study. I.P.K., S. M., S.K., M.S., M.P., A.G., and Anupama. N. assisted with animal experiments, animal imaging, in vitro experiments, or biochemical assays. J.M.J. assisted in pathological analysis. S.P. provided feedback on animal experiments and assisted with manuscript preparation. A.N., S. M., F.D., M.P., and C-W. L edited the manuscript and provided comments. E.H. and S.M. assisted with scRNA-seq experiments. P.C.R. provided scientific direction, established collaborations, prepared the manuscript with J.G., and allocated funding for the work.
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P.C.-R, S.P., and J.G. are inventors of a US provisional patent application 63/683,329 entitled compositions targeting FXR1 and methods of using the same for the treatment of diseases and disorders associated with FXR1 expression. The remaining authors declare no competing interests.
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George, J., Ma, X., Kadamberi, I.P. et al. Single-cell transcriptomics reveals FXR1 as an actionable target for siRNA therapy in ovarian cancer. Nat Commun (2026). https://doi.org/10.1038/s41467-026-71468-y
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DOI: https://doi.org/10.1038/s41467-026-71468-y
