# Mechanistic studies of gut microbiota-mediated immune activation against hepatocellular cancer

> **NIH NIH R01** · UNIVERSITY OF CONNECTICUT SCH OF MED/DNT · 2024 · $474,805

## Abstract

ABSTRACT
Anti-PD-1 antibody has been approved to treat distinct cancers including hepatocellular cancer (HCC); however,
the objective therapeutic response in human HCC patients is only about 14%. Microbes are now widely accepted
to play critical roles in cancer pathology, and targeting them to improve cancer treatment is an active research
area. To investigate the role of gut microbiota in HCC, a novel murine model was created which reflects the
typical features in human disease and expresses SV40 T antigen (TAg) as a trackable tumor specific antigen
(TSA). This model was used to study the influence of gut microbiota on HCC initiation and progression by treating
pre- or post-malignant mice with an antibiotic cocktail (ABX) that contains three types of antibiotics. ABX
treatment restored TSA CD8+ T-cell function, retarded hepatocarcinogenesis, and therapeutically slowed HCC
growth. Metagenomic assay demonstrated ABX treatment mediated an enrichment of Bacteroides.
Supplementation of Bacteroides thetaiotaomicron (B.th), one member of genus Bacteroides, acted similarly to
ABX in suppressing tumor growth and activating anti-tumor immune response, associating with the intratumoral
accumulation of CpG-rich genomic DNAs and increased expression of TLR9 in intratumoral dendritic cells (DCs)
and macrophages (MΦs). In particular, complete gut sterilization of HCC-bearing mice with five types of
antibiotics followed by B.th repopulation markedly improved the therapeutic efficacy of αPD1 Abs. Single cell
RNA sequencing (scRNA-seq) revealed that B.th repopulation was associated with significant suppression of
Kruppel-like factor 2 (KLF2) and significant increase of TLR9. Previous studies have demonstrated that KLF2 is
a transcription factor which negatively controls expression of TLR9, phagocytosis in MФs and DCs, and function
of T cells. Together, these results imply that B.th suppresses KLF2 expression, which abrogates its suppressive
effect on TLR9, a pattern recognition receptor (PRR). The resultant increased TLR9 on sentinel MФs and DCs
recognizes B.th-derived CpG-rich DNAs in tumors to activate TSA effector CD8+ T cells against HCC. Thus, this
study will test the hypothesis that gut Bacteroides activate anti-HCC immune responses and improve anti-HCC
immunotherapy by modulating immunological function of DCs and MФs via KLF2/TLR9/CpG molecular
pathways. Aim 1 will dissect the molecular mechanisms by which B.th modulates DCs and MΦs to improve anti-
HCC immunity and therapeutic effect through KLF2 and TLR9 pathways; aim 2 will dissect the cellular
mechanisms by which B.th modulates DCs and MΦs to improve anti-HCC immunity and therapeutic effect; and
aim 3 will investigate therapeutic and immune regulatory effect of gut microbiota in human HCC patient response
to αPD-1 Ab treatment. Successful completion of the proposed studies will provide insight into the cellular and
molecular mechanisms underlying B.th-activated anti-HCC immune response and advance gut ...

## Key facts

- **NIH application ID:** 11076418
- **Project number:** 7R01CA250536-04
- **Recipient organization:** UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
- **Principal Investigator:** Guangfu Li
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $474,805
- **Award type:** 7
- **Project period:** 2021-09-23 → 2026-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11076418

## Citation

> US National Institutes of Health, RePORTER application 11076418, Mechanistic studies of gut microbiota-mediated immune activation against hepatocellular cancer (7R01CA250536-04). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/11076418. Licensed CC0.

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