# LIFUS-driven engineered bacteria reprogram immunosuppressive niches via mechano-NOTCH signaling

## TL;DR

Scientists engineered bacteria to use ultrasound to create mechanical forces in tumors, which helps T cells fight cancer more effectively.

## Contribution

A novel mechano-immunotherapy using engineered bacteria and ultrasound to disrupt immunosuppressive tumor niches via NOTCH signaling.

## Key findings

- LIFUS-activated gas vesicles reduce cancer-associated fibroblasts and disrupt CAF-CD8+ T cell communication.
- Mechanotransduction via NOTCH signaling enhances CD8+ T cell infiltration and cytotoxicity in tumors.
- LIFUS-GV mechano-priming improves adoptive T cell therapy efficacy in solid tumors.

## Abstract

Solid tumors impose coupled stromal and immunologic barriers that limit T cell infiltration and function. Here, we engineer Salmonella VNP20009 to express gas vesicles (GVs), creating an intratumoral cavitation source that converts low-intensity focused ultrasound (LIFUS) into localized mechanical forces. LIFUS-activated GVs remodel the tumor microenvironment by reducing cancer-associated fibroblast (CAF) abundance, decompressing the matrix, and selectively disrupting CAF-CD8+ T cell communication via a mechanosensitive Notch1-Jagged1 axis. Single-cell RNA sequencing reveals a redistribution of CD8+ T cell states, characterized by enrichment of cytotoxic effector populations and attenuation of NOTCH signaling in memory-associated cells. These biomechanical changes enhance intratumoral CD8+ T cell infiltration and restore effector cytokine production. Leveraging this mechanism, we develop a mechano-priming approach for adoptive T cell therapies. Pre-conditioning with LIFUS-driven GVs improves CD8+ T cell cytotoxicity, strengthens tumor cell adhesion, reduces exhaustion signatures, and achieves durable tumor control and extended survival in orthotopic and metastatic models.

•Engineered VNP/ARG-GVs enable ultrasound imaging and tumor mechanotransduction•LIFUS-activated GVs generate forces that disrupt CAF-CD8+ T cell NOTCH signaling•GV-mediated mechanotransduction reverses immunosuppression and boosts cytotoxicity•LIFUS-GV mechano-priming improves OT-1 and CAR-T efficacy in solid tumors

Engineered VNP/ARG-GVs enable ultrasound imaging and tumor mechanotransduction

LIFUS-activated GVs generate forces that disrupt CAF-CD8+ T cell NOTCH signaling

GV-mediated mechanotransduction reverses immunosuppression and boosts cytotoxicity

LIFUS-GV mechano-priming improves OT-1 and CAR-T efficacy in solid tumors

Lin et al. engineer bacteria expressing gas vesicles to convert low-intensity ultrasound into localized mechanical forces within tumors. This mechano-immunotherapy remodels the stromal-immune microenvironment, disrupts CAF-CD8+ T cell NOTCH signaling, and enhances T cell-based cancer immunotherapy efficacy.