Xiao Ding

Objective Probiotic Lactococcus lactis is known to confer health benefits to humans. Here, we aimed to investigate the role of L. lactis in colorectal cancer (CRC). Design L. lactis abundance was evaluated in patients with CRC (n=489) and healthy individuals (n=536). L. lactis was isolated from healthy human stools with verification by whole genome sequencing. The effect of L. lactis on CRC tumourigenesis was assessed in transgenic Apc Min/+ mice and carcinogen-induced CRC mice. Faecal microbiota was profiled by metagenomic sequencing. Candidate proteins were characterised by nano liquid chromatography-mass spectrometry. Biological function of L. lactis conditioned medium ( HkyuLL 10 -CM) and functional protein was studied in human CRC cells, patient-derived organoids and xenograft mice. Results Faecal L. lactis was depleted in patients with CRC. A new L. lactis strain was isolated from human stools and nomenclated as HkyuLL 10. HkyuLL 10 supplementation suppressed CRC tumourigenesis in Apc Min/+ mice, and this tumour-suppressing effect was confirmed in mice with carcinogen-induced CRC. Microbiota profiling revealed probiotic enrichment including Lactobacillus johnsonii in HkyuLL 10 -treated mice. HkyuLL 10 -CM significantly abrogated the growth of human CRC cells and patient-derived organoids. Such protective effect was attributed to HkyuLL 10 -secreted proteins, and we identified that α-mannosidase was the functional protein. The antitumourigenic effect of α-mannosidase was demonstrated in human CRC cells and organoids, and its supplementation significantly reduced tumour growth in xenograft mice. Conclusion HkyuLL 10 suppresses CRC tumourigenesis in mice through restoring gut microbiota and secreting functional protein α-mannosidase. HkyuLL 10 administration may serve as a prophylactic measure against CRC.

Peptostreptococcus stomatis (P. stomatis) is enriched in colorectal cancer (CRC), but its causality and translational implications in CRC are unknown. Here, we show that P. stomatis accelerates colonic tumorigenesis in ApcMin/+ and azoxymethane/dextran sodium sulfate (AOM-DSS) models by inducing cell proliferation, suppressing apoptosis, and impairing gut barrier function. P. stomatis adheres to CRC cells through its surface protein fructose-1,6-bisphosphate aldolase (FBA) that binds to the integrin α6/β4 receptor on CRC cells, leading to the activation of ERBB2 and the downstream MEK-ERK-p90 cascade. Blockade of the FBA-integrin α6/β4 abolishes ERBB2-mitogen-activated protein kinase (MAPK) activation and the protumorigenic effect of P. stomatis. P. stomatis-driven ERBB2 activation bypasses receptor tyrosine kinase (RTK) blockade by EGFR inhibitors (cetuximab, erlotinib), leading to drug resistance in xenograft and spontaneous CRC models of KRAS-wild-type CRC. P. stomatis also abrogates BRAF inhibitor (vemurafenib) efficacy in BRAFV600E-mutant CRC xenografts. Thus, we identify P. stomatis as an oncogenic bacterium and a contributory factor for non-responsiveness to RTK inhibitors in CRC.

Chemoresistance is a main cause of colorectal cancer (CRC) treatment failure. We identified that Bacteroides fragilis is enriched in patients with CRC resistant to chemotherapy in two independent cohorts, and its abundance is associated with poor survival. Consistently, administration of B. fragilis to CRC xenografts and Apc Min/+ - and AOM/DSS-induced CRC mice all significantly attenuated the antitumor efficacy of 5-FU and OXA. Mechanistically, B. fragilis colonized colon tumors and mediated its effect via its surface protein SusD/RagB binding to the Notch1 receptor in CRC cells, leading to activation of the Notch1 signaling pathway and the induction of epithelial-to-mesenchymal transition (EMT)/stemness to suppress chemotherapy-induced apoptosis. Either deletion of SusD/RagB or blockade of Notch1 signaling abrogated B. fragilis -mediated chemoresistance. Finally, B. fragilis -targeting phage VA7 selectively suppressed B. fragilis and restored chemosensitivity in preclinical CRC mouse models. Our findings have offered insights into the potential of precise gut microbiota manipulation for the clinical management of CRC. • B. fragilis is enriched in non-responders of patients with CRC to chemotherapy • B. fragilis compromises 5-FU/OXA efficacy in CRC cells and in mouse models • B. fragilis surface SusD/RagB binds to host receptor Notch1, inducing chemoresistance • Phage VA7 eliminates B. fragilis and restores chemosensitivity of CRC in mice Ding et al. identify Bacteroides fragilis as a bacterial pathogen that promotes colorectal cancer (CRC) chemoresistance by activating host Notch1 signaling through its surface protein SusD/RagB. Targeting B. fragilis with a phage therapy restores chemotherapy sensitivity in CRC mouse models.

Liver fibrosis is a major contributor to the morbidity and mortality associated with liver diseases, yet effective treatment options remain limited. Hepatic stellate cells (HSCs) are a promising target for hepatic fibrogenesis due to their pivotal role in disease progression. Our previous research has demonstrated the potential of Dihydrotanshinone I (DHI), a lipophilic component derived from the natural herb Salvia miltiorrhiza Bunge, in treating liver fibrosis by inhibiting the YAP/TEAD2 interaction in HSCs. However, the clinical application of DHI faces challenges due to its poor aqueous solubility and lack of specificity for HSCs. Additionally, recent studies have implicated the impact of liver microbiota, distinct from gut microbiota, on the pathogenesis of liver diseases. In this study, we have developed an HSC- and microbiome-specific delivery system for DHI by conjugating prebiotic-like cyclodextrin (CD) with vitamin A, utilizing PEG2000 as a linker (VAP2000@CD). Our results demonstrate that VAP2000@CD markedly enhances the cellular uptake in human HSC line LX-2 and enhances the deposition of DHI in the fibrotic liver in vivo. Subsequently, intervention with DHI-VAP2000@CD has shown a notable reduction in bile duct-like structure proliferation, collagen accumulation, and the expression of fibrogenesis-associated genes in rats subjected to bile duct ligation. These effects may be attributed to the regulation of the YAP/TEAD2 interaction. Importantly, the DHI-VAP2000@CD intervention has also restored microbial homeostasis in the liver, promoting the amelioration of liver inflammation. Overall, our findings indicate that DHI-VAP2000@CD represents a promising therapeutic approach for liver fibrosis by specifically targeting HSCs and restoring the liver microbial balance.