FASN-mediated fatty acid biosynthesis remodels immune environment in Clonorchis sinensis infection-related intrahepatic cholangiocarcinoma

BACKGROUND & AIMS

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver cancer with high lethality. Clonorchis sinensis (C. sinensis) infection is an important risk factor for ICC. Here we investigated the clinical impact and underlying molecular characteristics of C. sinensis-infected ICC.

METHODS

We performed single-cell RNA sequencing, whole exome sequencing, RNA-sequencing, metabolomics and spatial transcriptomics in 251 ICC patients from three medical centers. The alterations of metabolic and immune microenvironment of C. sinensis-infected ICCs were validated through in vitro co-culture system and hydrodynamic injection ICC mouse model.

RESULTS

We revealed that C. sinensis infection was significantly associated with ICC patients' overall survival and immunotherapy response. Fatty acid biosynthesis and the expression of FASN, a key enzyme catalyzing long-chain fatty acid synthesis, were significantly enriched in C. sinensis-infected ICCs. ICC cell lines treated with C. sinensis-produced excretory/secretory products (ESPs) displayed an elevation of FASN and free fatty acid. The metabolic alteration of tumor cells was closely correlated with the enrichment of tumor-associated macrophage-like (TAM-like) macrophages and the impairment function of T cells, which led to the immunosuppressive microenvironment formation and tumor progression. Spatial transcriptomics analysis revealed that malignant cells were in closer juxtaposition with TAM-like macrophages in C. sinensis-infected ICCs than non-C. sinensis-infected ICCs. Importantly, FASN inhibitor significantly reversed immunosuppressive microenvironment and enhanced anti-PD-1 efficacy in ICC mouse models treated with ESPs from C. sinensis.

CONCLUSIONS

We uncover the metabolic signature and immune microenvironment of C. sinensis-infected ICCs and highlight the combination of FASN inhibitors with immunotherapy as a promising strategy for treating C. sinensis-infected ICCs.

IMPACT AND IMPLICATIONS

C. sinensis-infected ICC patients have a poorer prognosis and worse response to immunotherapy than non-C. sinensis-infected ICCs. The underlying molecular characteristics of C. sinensis-infected ICCs remains unclear. Herein, we demonstrate that up-regulation of FASN and free fatty acids in C. sinensis-infected ICCs leads to immunosuppressive microenvironment formation and tumor progression. Thus, administration of FASN inhibitors could significantly reverse immunosuppressive environment and further enhance anti-PD-1 efficacy in combating C. sinensis-infected ICCs.

Thioholgamide A, a New Anti-Proliferative Anti-Tumor Agent, Modulates Macrophage Polarization and Metabolism

Natural products represent powerful tools searching for novel anticancer drugs. Thioholgamide A (thioA) is a ribosomally synthesized and post-translationally modified peptide, which has been identified as a product of Streptomyces sp. MUSC 136T. In this study, we provide a comprehensive biological profile of thioA, elucidating its effects on different hallmarks of cancer in tumor cells as well as in macrophages as crucial players of the tumor microenvironment. In 2D and 3D in vitro cell culture models thioA showed potent anti-proliferative activities in cancer cells at nanomolar concentrations. Anti-proliferative actions were confirmed in vivo in zebrafish embryos. Cytotoxicity was only induced at several-fold higher concentrations, as assessed by live-cell microscopy and biochemical analyses. ThioA exhibited a potent modulation of cell metabolism by inhibiting oxidative phosphorylation, as determined in a live-cell metabolic assay platform. The metabolic modulation caused a repolarization of in vitro differentiated and polarized tumor-promoting human monocyte-derived macrophages: ThioA-treated macrophages showed an altered morphology and a modulated expression of genes and surface markers. Taken together, the metabolic regulator thioA revealed low activities in non-tumorigenic cells and an interesting anti-cancer profile by orchestrating different hallmarks of cancer, both in tumor cells as well as in macrophages as part of the tumor microenvironment.