Harnessing gamma delta T-cells for immunotherapy for hepatocellular carcinoma

Background More effective immunotherapeutic strategies are urgently needed to reduce the high mortality of hepatocellular carcinoma (HCC). In previous work, I demonstrated for the first time the therapeutic potential of gamma delta (γδ) T-cells for HCC.

I showed that γδ T-cells exhibit a tissue-resident memory (TRM) phenotype in human liver and HCC, with increased liver-homing chemokine receptor expression and superior anti-tumour function. However a main subset, Vγ9Vδ2 T-cells, were selectively depleted in HCC, which correlated with poorer prognosis.

I subsequently devised a novel therapeutic approach for HCC, demonstrating in vitro that a de novo TRM phenotype can be recapitulated on expanded blood Vγ9Vδ2 T-cells for adoptive cell transfer, and combined with intra-tumoural delivery of the aminobisphosphonate Zoledronate to significantly enhance Vγ9Vδ2 TRM cell activation and lysis of HCC cell lines (Zakeri et al.

Nature Communications, 2022).

Aims In this proposal, I will study for the first time the mechanisms of Vγ9Vδ2 T-cell recruitment across human hepatic sinusoidal- and HCC-derived endothelial cells, and evaluate whether an induced TRM phenotype can boost expanded Vγ9Vδ2 T-cell recruitment into the tumour.

I will utilise 3D preclinical models to develop a novel dual therapeutic approach combining intra-tumoural Zoledronate with expanded Vγ9Vδ2 TRM cells for clinical translation, and explore strategies to overcome constraints from the tumour microenvironment.

Methods Using flow adhesion assays and high-resolution confocal microscopy, I will examine Vγ9Vδ2 T-cell recruitment across hepatic sinusoidal- and HCC-derived endothelial cells, with induced shear stress replicating conditions in hepatic sinusoids.

I will add in tumour-conditioned media to replicate the HCC microenvironment, and compare expanded Vγ9Vδ2 TRM versus non-TRM Vγ9Vδ2 T-cell recruitment.

Utilising 3D HCC spheroids, and precision cut human liver and liver tumour slices, I will examine the efficacy of a combined approach of intra-tumoural Zoledronate and adoptively transferred Zoledronate-expanded Vγ9Vδ2 TRM cells, to determine an optimal regimen for inducing tumour lysis whilst minimising off-target effects.

I will examine whether targeting pro-tumourigenic factors enriched in the HCC microenvironment can further enhance the efficacy of this Vγ9Vδ2 T-cell therapeutic approach.

How the results of this research will be used Collectively this proposal will provide important insights to inform the design of a future trial comprising Vγ9Vδ2 T-cell immunotherapy alongside targeting of the HCC microenvironment, with the future goal of developing a more universally effective immunotherapy for patients with HCC.

In the broader context, the insights gained might also be applicable for the treatment of other solid tumour types.