A single injection awakens dormant immune cells inside tumors, transforming them into relentless cancer killers without invasive cell extraction.
Story Snapshot
- KAIST researchers reprogram tumor macrophages on-site using mRNA-loaded nanoparticles, bypassing ex vivo CAR therapy limitations.
- Mouse melanoma models show slowed tumor growth and body-wide immune activation after direct tumor injection.
- Led by Professor Ji-Ho Park, this advances solid tumor immunotherapy amid challenges like immunosuppressive environments.
- Preclinical success promises simpler, efficient treatments for cancers resistant to current CAR-T approaches.
- Announced January 11, 2026, positions KAIST for potential human trials and pharma partnerships.
KAIST’s Nanoparticle Injection Reprograms Macrophages In Vivo
KAIST researchers inject lipid nanoparticles carrying mRNA into tumors. These nanoparticles target resident macrophages, which absorb the mRNA and produce chimeric antigen receptor (CAR) proteins. Macrophages convert into CAR-macrophages that directly attack cancer cells. This process activates nearby immune cells, sparking a broader anti-tumor response. Professor Ji-Ho Park’s team announced results on January 11, 2026.
Injection turns sleeping tumor immune cells into cancer fighters https://t.co/fjALv5jz3V
— Un1v3rs0 Z3r0 (@Un1v3rs0Z3r0) January 11, 2026
Traditional CAR therapies extract patient cells, modify them outside the body, and reinfuse them. Solid tumors resist this due to poor cell delivery and hostile microenvironments where macrophages protect cancer instead of fighting it. KAIST’s method reprograms these “sleeping” macrophages on-site, overcoming delivery barriers and suppression.
Mouse Models Demonstrate Tumor Suppression and Systemic Effects
In melanoma mouse models, injected CAR-macrophages slowed tumor growth significantly. Treated tumors shrank while controls expanded. The therapy induced systemic immunity, reducing growth of untreated distant tumors. Macrophages persisted long enough to mount sustained attacks without off-site CAR expression risks.
KAIST data shows CAR-macrophages kill cancer cells efficiently and recruit T-cells for amplified response. This body-wide effect hints at metastasis control, a key solid tumor challenge. Preclinical results align with American conservative values emphasizing practical, efficient innovation over complex bureaucracy in healthcare.
Overcoming CAR Therapy Limitations for Solid Tumors
CAR-T succeeds in blood cancers, with some patients achieving over 10-year survival. Solid tumors like melanoma evade it through immunosuppressive macrophages and physical barriers. KAIST flips these macrophages from allies to enemies of cancer. Direct injection simplifies logistics, cuts costs, and reduces patient burden compared to multi-week ex vivo cycles.
Prior innovations include USC’s 2025 ultrasound-activated CAR-T, extending activity from hours to days in prostate models. IU’s T-reg reprogramming targeted breast and colorectal cancers. KAIST builds on lipid nanoparticle tech for precise macrophage delivery. These align on in vivo strategies, strengthening evidence for clinical translation grounded in mouse efficacy.
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Path to Clinical Application and Broader Impacts
KAIST holds intellectual property on the nanoparticles, eyeing partnerships for scaling. Short-term, fewer clinic visits benefit patients in resource-limited areas. Long-term, adaptable for breast or brain cancers, it could extend melanoma survival from months to years. Economic sense favors this over costly cell manufacturing, promoting accessible care.
Experts like Park call it a “new concept” beating delivery and suppression hurdles. USC’s Longwei Liu notes similar reductions in treatment frequency. Preclinical consistency across labs supports optimism, though human trials remain essential. Common sense demands rigorous testing before deployment, prioritizing safety and proven results.
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Sources:
https://viterbischool.usc.edu/news/2025/04/new-smart-immune-cells-a-breakthrough-for-long-lasting-tumor-destruction/
https://www.sciencedaily.com/releases/2026/01/260110211207.htm
https://medicine.iu.edu/news/2025/09/science-immunology-t-reg-cells
https://honcology.com/blog/7-breakthroughs-in-patient-centric-oncology-care-in-2026
https://braintumourresearch.org/blogs/latest-news/blog-new-trial-for-brain-tumour-patients-to-start-in-early-2026-what-is-it-and-how-will-it-work
https://scitechdaily.com/researchers-discover-new-way-to-wake-up-cancer-killing-t-cells/
https://www.uclahealth.org/news/release/ucla-scientists-develop-one-product-fits-all-immunotherapy-2
https://news.unchealthcare.org/2026/01/unc-researchers-show-combination-therapy-effective-for-brain-cancer/
https://www.aacr.org/blog/2025/12/18/cancer-in-2025-funding-new-treatments-and-breakthrough-ideas/
