Lack of Evidence that Ursodeoxycholic Acid’s Effects on the Gut Microbiome Influence Colorectal Adenoma Risk

Pearson, T.; Caporaso, J. G.; Yellowhair, M.; Bokulich, N. A.; Roe, D. J.; Wertheim, B. C.; Linhart, M.; Martinez, J. A.; Bilagody, C.; Hornstra, H.; Alberts, D. S.; Lance, P.; Thompson, P. A.

doi:10.1101/237495

bioRxiv · 10.1101/237495

Lack of Evidence that Ursodeoxycholic Acid’s Effects on the Gut Microbiome Influence Colorectal Adenoma Risk

Pearson, T.·Caporaso, J. G.·Yellowhair, M.·Bokulich, N. A.·Roe, D. J.·Wertheim, B. C.·Linhart, M.·Martinez, J. A.·Bilagody, C.·Hornstra, H.·Alberts, D. S.·Lance, P.·Thompson, P. A.

View original source ↗Export metadata ↓

Abstract

ObjectiveWe previously reported that Ursodeoxycholic acid (UDCA), a therapeutic bile acid, reduces risk for advanced colorectal adenoma in men but not women. Interactions between the gut microbiome and fecal bile acid composition as a factor in colon cancer neoplasia have been postulated but evidence is limited to small cohorts and animal studies.\n\nDesignUsing banked stool samples collected as part of a phase III randomized clinical trial of UDCA for the prevention of colorectal neoplasia, we compared change in the microbiome composition after 3 years intervention in a subset of participants randomized to 8-10 mg/kg of body weight UDCA (n=198) to placebo (n=203). UDCA effects on the microbiome, sex and adenoma outcome were investigated.\n\nResultsStudy participants randomized to UDCA experienced compositional changes in their microbiome that were statistically more similar to other individuals in the UDCA arm than to those in the placebo arm. This change reflected an UDCA-associated shift in microbial community distance metrics (P <0.001), independent of sex, with no evidence of UDCA effect on microbial richness (P > 0.05). These UDCA-associated shifts in microbial community distance metrics from baseline to end-of-study were not associated with risk of any or advanced adenoma (all P> 0.05) in men or women.\n\nConclusionDespite a large sampling of randomized clinical trial participants, daily UDCA use only modestly influenced the relative abundance of microbial species in stool with no evidence for effects of UDCA on stool microbial community composition as a modifier of colorectal adenoma risk.\n\nSUMMARYO_ST_ABSWhat is already known about this subject?C_ST_ABSO_LIUrsodeoxycholic acid (UDCA) is a therapeutic bile acid used in the treatment of primary biliary cirrhosis (PBC) and investigated for anti-cancer activity in the colon\nC_LIO_LIIn humans, UDCA is produced in the colon from the conjugation of primary bile acids by intestinal bacteria\nC_LIO_LIIntestinal bacteria play a critical role in human intestinal health and disease including a hypothesized role in the development of colorectal cancer.\nC_LIO_LIUDCA was found to reduce the risk of more advanced colorectal adenoma with effects present in men but not women.\nC_LIO_LITherapeutic UDCA was recently shown to reduce the extent of bacterial dysbiosis in patients with PBC\nC_LI\n\nWhat are the new findings?O_LIAmong a population of patients with colorectal adenoma, low dose oral UDCA taken daily produced modest changes in fecal bacterial composition\nC_LIO_LIUDCA associated changes in the gut microbiome were similar in men and women.\nC_LIO_LIUDCA associated changes in the gut micobiome were not associated with risk of any or advanced colorectal adenoma in the patient population.\nC_LI\n\nHow might it impact on clinical practice in the foreseeable future?O_LIThese findings confirm effects of oral UDCA on the microbiome that may be beneficial for patients with PBC.\nC_LIO_LIThese findings suggest that the anti-cancer effects of UDCA for colorectal adenoma prevention are not due to major effects of UDCA on the gut microbiome.\nC_LI

Explore related subjects

cancer biology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Pearson, T., Caporaso, J. G., Yellowhair, M., Bokulich, N. A., Roe, D. J., Wertheim, B. C., Linhart, M., Martinez, J. A., Bilagody, C., Hornstra, H., Alberts, D. S., Lance, P., Thompson, P. A.. 2017-12-21. Lack of Evidence that Ursodeoxycholic Acid’s Effects on the Gut Microbiome Influence Colorectal Adenoma Risk. https://doi.org/10.1101/237495

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

TROP2 and immune gene expression by African ancestry in triple-negative breast cancer

Purpose: TROP2 is a treatment target in triple-negative breast cancer (TNBC). TACSTD2 encodes TROP2, while PDCD1 encodes the immune protein PD-1. We investigated whether these genes differ by race or African genetic ancestry and whether the reported link between higher TACSTD2 and lower immune-gene expression partly reflects the mixture of cells in tumor samples. Methods: We analyzed TNBC tumors from TCGA (n = 107) and GSE268851 (n = 253; ancestry data for 229), together with spatial, normal-breast, and protein datasets. Regression models adjusted for age, tumor stage, and a score based on epithelial gene expression. We compared TACSTD2 with other epithelial markers using paired bootstrap analysis. Results: TACSTD2 was detected in nearly all tumors, with no significant differences by race or ancestry. Higher African ancestry was linked to higher PDCD1 expression in TCGA (P = 0.00039), but not in GSE268851. In GSE268851, higher TACSTD2 remained associated with lower CD8A, GZMB, and cytotoxic score after epithelial adjustment (all q < 0.003). These associations were stronger than those for EPCAM; the CD8A association was also stronger than that for KRT8. TACSTD2 was 1.55-fold higher in TNBC than in normal breast and correlated with TROP2 protein (Spearman rho = 0.74). Conclusion: TACSTD2 was widely expressed in the TNBC groups studied, while the ancestry-PDCD1 association differed between cohorts. Epithelial gene expression did not fully explain some negative TACSTD2-immune associations, and some were stronger than those for other epithelial markers such as EPCAM.

cancer biology↗

bioRxiv2026

Quantifying subcellular organization from localization to co-occurrence with InSpace

Cell identity and function depend not only on molecular abundance, but also on how molecules are organized within cells. Although spatial transcriptomics now resolves individual RNA molecules within cells, routine computational workflows reduce these measurements to cell-by-gene count matrices, retaining abundance while discarding information about intracellular localization and molecular co-occurrence. This loss of spatial information creates a need for scalable methods that preserve subcellular detail and enable comparisons across diverse cellular morphologies. Therefore, we present InSpace, a scalable framework for quantifying these complementary dimensions of subcellular organization. InSpace-R maps transcripts onto a continuous radial coordinate anchored to nuclear and cell boundaries, while InSpace-C measures distance-dependent co-occurrence or depletion of molecular pairs. Simulations and orthogonal biochemical references support accurate measurements, with scalability demonstrated on datasets containing 275 million transcripts. RNA-RNA and RNA-DNA analyses recover organelle-linked neighbourhoods and associations between nascent transcripts and their genomic origins. Analysis of B and plasma cells across 58 tumour datasets spanning 12 cancer types reveals that reduced MHC-II transcript abundance accompanies more peripheral localization and stronger mutual co-occurrence, separating these transcripts from a program enriched for ER-targeted proteins. InSpace makes intracellular organization accessible alongside abundance, enabling discovery of spatial programs that distinguish cellular states and generate hypotheses about their functional specialization.

cancer biology↗

bioRxiv2026

Age-based shifts in multicellular community organization and abundance in HPV-Negative Head and Neck Cancer

Aging represents a fundamental driver of cancer risk and progression, yet the mechanisms by which aging reshapes the tumor microenvironment remain incompletely understood. To interrogate how aging alters cellular and microenvironmental organization in cancer, we developed an integrated single-cell atlas of HPV-negative head and neck squamous cell carcinoma (HNSCC) encompassing 73 patients aged 18-91 years. Using a multi-layered computational framework combining NMF-based module discovery and partial correlation network analysis, we reveal that age-associated differences in tumor composition are driven primarily by selective shifts in cell type abundance and organization rather than widespread age-dependent transcriptional rewiring. We identify an age-enriched cellular community centered on basal-like squamous epithelial states linked to epithelial-mesenchymal transition, matrix-associated myofibroblast-like CAFs, and FOLR2+ macrophages, which secrete immunosuppressive and ECM-remodeling factors. Cross-dataset in-silico validation via TCGA transcriptomes, spatial transcriptomics, and mouse tumor models confirms the correlation of these cell types across patients, specific ligand-receptor usage, and increased proportions of epithelial and stromal cells in aged mouse models. Among epithelial cell-intrinsic age-associated transcriptional changes, midkine (MDK) emerges as a rare but robust tumor-derived signal linked to stromal remodeling, immunosuppression, and invasive epithelial programs. These findings reveal conserved mechanisms of age-dependent cellular reorganization in the tumor microenvironment and identify MDK and associated stromal-remodeling pathways as potential intervention points for age-stratified cancer therapy.

cancer biology↗