Immunosuppressive CD10+ALPL+ neutrophils promote resistance to anti-PD-1 therapy in HCC by mediating irreversible exhaustion of T cells

Abstract

Background & aims: Remodeling the tumor microenvironment is a critical strategy for treating advanced hepatocellular carcinoma (HCC). Yet, how distinct cell populations in the microenvironment mediate tumor resistance to immunotherapies, such as anti-PD-1, remains poorly understood.

Methods: We analyzed the transcriptomic profile, at a single-cell resolution, of tumor tissues from patients with HCC scheduled to receive anti-PD-1-based immunotherapy. Our comparative analysis and experimental validation using flow cytometry and histopathological analysis uncovered a discrete subpopulation of cells associated with resistance to anti-PD-1 treatment in patients and a rat model. A TurboID-based proximity labeling approach was deployed to gain mechanistic insights into the reprogramming of the HCC microenvironment.

Results: We identified CD10⁺ALPL⁺ neutrophils as being associated with resistance to anti-PD-1 treatment. These neutrophils exhibited a strong immunosuppressive activity by inducing an apparent "irreversible" exhaustion of T cells in terms of cell number, frequency, and gene profile. Mechanistically, CD10⁺ALPL⁺ neutrophils were induced by tumor cells, i.e., tumor-secreted NAMPT reprogrammed CD10⁺ALPL⁺ neutrophils through NTRK1, maintaining them in an immature state and inhibiting their maturation and activation.

Conclusions: Collectively, our results reveal a fundamental mechanism by which CD10⁺ALPL⁺ neutrophils contribute to tumor immune escape from durable anti-PD-1 treatment. These data also provide further insights into novel immunotherapy targets and possible synergistic treatment regimens.

Impact and implications: Herein, we discovered that tumor cells reprogrammed CD10⁺ALPL⁺ neutrophils to induce the "irreversible" exhaustion of T cells and hence allow tumors to escape from the intended effects of anti-PD-1 treatment. Our data provided a new theoretical basis for the elucidation of special cell populations and revealed a molecular mechanism underpinning resistance to immunotherapy. Targeting these cells alongside existing immunotherapy could be looked at as a potentially more effective therapeutic approach.

Keywords: Hepatocellular carcinoma; Immunotherapy resistance; Irreversible T-cell exhaustion; NAMPT-NTRK1 axis; Reprogramming of microenvironment.