# Enhancing cancer killing and natural killer cell persistence by targeting NOXA, a predictor of poor patient survival

## TL;DR

Deleting a protein called NOXA in natural killer cells improves their survival and cancer-killing ability, potentially boosting cancer immunotherapy.

## Contribution

This study identifies NOXA as a key target for improving NK cell persistence and function in cancer immunotherapy.

## Key findings

- NOXA deletion in NK cells enhances their serial cancer-killing efficacy and post-cryopreservation cytotoxicity.
- NOXA-KO NK cells show improved metabolic fitness and proliferative capacity.
- NOXA deletion rescues NK cell survival in cytokine-rich tumor microenvironments.

## Abstract

Natural killer (NK)-cell-based therapeutics have emerged as promising modalities in cancer immunotherapy due to their potent ability to target and kill cancer cells. However, their clinical efficacy is often constrained by the limited in vivo persistence of NK, which hinders sustained therapeutic effects. This study aimed to enhance NK cell survival and functionality by inhibiting apoptosis, thereby boosting the long-term efficacy of NK-cell-mediated therapeutics. Through univariate and multivariate Cox proportional hazards regression analyses, we found that the high expression of Bcl-2-interacting mediator of cell death (BCL2L11 [BIM]) and phorbol-12-myristate-13-acetate-induced protein 1 (PMAIP1 [NOXA]) in NK cells is associated with poorer survival across various cancer types. Based on potential clinical relevance, we employed CRISPR-Cas9 technology with single-guide RNA to knock out NOXA in NK cells. This modification enhanced the serial cancer-killing efficacy in repeated assays and patient-derived organoid models. In contrast, BIM-knockout (KO) did not confer any additional benefits. Additionally, NOXA-KO NK cells exhibited enhanced post-cryopreservation cytotoxicity, superior metabolic fitness, and extended proliferative capacity. These findings highlight the potential of NOXA-KO NK cells to advance the efficacy of NK-cell-based cancer therapies.

Survival analyses by Kang and colleagues linked elevated NOXA expression in NK cells to poor cancer outcomes. We show that TME-enriched IL-6 and transforming growth factor β1 (TGF-β1) strongly induce NOXA, driving NK cell apoptosis and functional exhaustion. NOXA deletion rescued NK cell survival and cytotoxicity in cytokine-rich TMEs, identifying NOXA as a target to enhance NK cell immunotherapy.