This study evaluated whether Tremella fuciformis polysaccharide (TFP) can retard colorectal cancer progression via effects on the gut microbiota–metabolome axis. The objective was to determine TFP effects on disease activity, tumor burden, gut microbial composition, fecal metabolites, and colonic signaling pathways related to inflammation and apoptosis.
Colorectal cancer was induced in C57BL/6J mice using the azoxymethane (AOM) plus dextran sulfate sodium (DSS) protocol. After model induction, mice received oral gavage of TFP or distilled water for 3 weeks. Outcomes included disease activity index (DAI), colon length, tumor number and volume, and histopathology.
Gut microbiota composition was profiled by metagenomic sequencing. Fecal metabolites were analyzed with untargeted metabolomics. Colonic protein expression of nuclear factor-κB (NF-κB), AMP-activated protein kinase alpha (AMPKα) and phosphorylated AMPKα (p-AMPKα), BAX, caspase-3, and cleaved caspase-3 was measured by Western blot. Separately, the metabolite pyridoxic acid—identified in fecal metabolomics—was tested in vitro for effects on HT-29 colorectal cancer cell viability and migration.
Compared with the untreated model group, TFP-treated mice showed significant improvements across clinical and pathological endpoints. DAI decreased from a median of 3.5 (IQR 2.8–4.5) in model controls to 2.0 (IQR 1.8–3.3) in the TFP group (P < 0.01). Mean colon length increased [(7.2 ± 1.1) cm vs (5.5 ± 0.5) cm; P < 0.05]. Pathological score was reduced [median 6 (3–8) vs 9 (8–10); P < 0.05]. Tumor burden fell: tumor count decreased [median 2 (1–3) vs 4 (3–4); P < 0.05] and tumor volume was smaller [(11.02 ± 7.88) mm3 vs (24.99 ± 3.38) mm3; P < 0.01]. These data indicate that TFP slowed disease progression and reduced tumor growth in this murine model.
Metagenomic analysis demonstrated that TFP significantly altered the gut microbial community structure (R2 = 0.173, P = 0.027). The TFP group showed relative enrichment of taxa described in the study as Candidatus Amulumruptor, Helicobacter, and Akkermansia. Several taxa that were relatively decreased after TFP treatment included Lactobacillus-related genera such as light strain Lactobacillus and other Lactobacillus species noted in the model group. Overall, 36 taxa differed between TFP and model groups by linear discriminant analysis (LDA score > 2.0). The authors reported distinct enrichment patterns between groups, with specific taxa elevated in the TFP-treated mice and others enriched in the untreated model group.
Untargeted fecal metabolomics identified a distinct metabolic profile in TFP-treated mice compared with model controls (R2 = 0.159, P = 0.004). Sixty fecal metabolites changed significantly; 33 were upregulated and 27 downregulated in the TFP group. Notably, pyridoxic acid showed a marked increase in relative abundance in TFP-treated mice (reported as 2.20-fold higher; P < 0.001). The study highlights pyridoxic acid as a candidate metabolite linking microbiota changes to anti-tumor effects.
The authors tested pyridoxic acid in vitro on HT-29 human colorectal cancer cells. Pyridoxic acid reduced HT-29 cell viability and suppressed migration in these assays. The observed cellular effects, together with correlations between pyridoxic acid abundance and certain upregulated bacteria, support a role for a microbiota–metabolite axis in the anti-tumor activity associated with TFP.
Western blot analysis of colon tissue revealed protein-level changes consistent with suppressed inflammation and increased apoptosis after TFP treatment. Specifically, TFP reduced NF-κB expression compared with the model group (0.65 ± 0.04 vs 1.00 ± 0.06; P < 0.01). TFP increased phosphorylated AMPKα (p-AMPKα) (2.94 ± 0.27 vs 1.00 ± 0.16; P < 0.001), upregulated BAX (6.77 ± 1.21 vs 1.00 ± 0.27; P < 0.001), and raised activated (cleaved) caspase-3 levels (2.10 ± 0.73 vs 1.00 ± 0.15; P < 0.05). These changes are consistent with activation of AMPK-mediated metabolic and apoptotic pathways and suppression of NF-κB–mediated inflammatory signaling in colonic tissue.
In this AOM/DSS murine colorectal cancer model, oral TFP administration for 3 weeks was associated with improved clinical and pathological outcomes, reshaping of the gut microbiota, altered fecal metabolite profiles with a notable increase in pyridoxic acid, and modulation of colonic signaling pathways characterized by NF-κB suppression and AMPK-driven apoptosis marker upregulation. In vitro data showed that pyridoxic acid inhibited viability and migration of HT-29 cells, supporting its potential functional role in the observed anti-tumor effect.
These results suggest that TFP may exert anti-colorectal cancer activity via a microbiota–metabolome axis that elevates pyridoxic acid and modulates inflammatory and apoptotic signaling. The abstract does not report TFP dosing amounts, safety or toxicity data, long-term outcomes, or direct evidence in humans; these details would be required to assess translational potential and clinical application.