Immune checkpoint inhibitors are a groundbreaking innovation in the field of cancer therapy, significantly altering the way we approach treatment for various malignancies. These therapies are designed to bolster the immune system’s ability to recognize and destroy cancer cells more effectively. However, a significant challenge remains: fewer than 20% of cancer patients currently benefit from these treatments. This stark reality underscores a pressing need for novel therapeutic strategies tailored to meet the varying responses among patients, particularly those who do not respond to existing therapies.
Researchers from the Korea Advanced Institute of Science and Technology (KAIST) have made a pivotal discovery that could change the dynamics of lung cancer treatment. Their study has identified a crucial RNA-binding protein, known as DEAD-box helicase 54 (DDX54), as the master regulator that inhibits the effectiveness of immunotherapy in patients. This finding could pave the way for innovative approaches to enhance the responsiveness of immune cells, particularly in cases where tumors display resistance to standard treatments. The technology arising from this research has already been transferred to a faculty startup, BioRevert Inc., which is now developing it as a companion therapy, with plans for clinical trials to begin by 2028.
The research team, led by Professor Kwang-Hyun Cho of KAIST’s Department of Bio and Brain Engineering, revealed that DDX54 plays a critical role in lung cancer cells’ ability to evade the immune response. By suppressing DDX54, the researchers noted a marked increase in immune cell infiltration into tumors, leading to a significantly enhanced efficacy of immunotherapy. The research, published in the prestigious Proceedings of the National Academy of Sciences, delineates a new pathway for therapeutic intervention aimed at boosting the effectiveness of immune checkpoint inhibitors, which include anti-PD-1 and anti-PD-L1 antibodies.
Despite the promise of immunotherapy, the low response rates among cancer patients continue to pose a considerable obstacle. To identify potential responders, the FDA recently approved tumor mutational burden (TMB) as a key biomarker for immunotherapy. Cancers that exhibit high mutation rates are generally more amenable to immune checkpoint inhibitors. Nevertheless, even tumors with elevated TMB can sometimes exhibit what is known as an “immune-desert” phenotype, wherein immune cell infiltration is severely restricted, resulting in suboptimal treatment outcomes.
In their investigation, Professor Cho and his research team conducted a comprehensive analysis of transcriptomic and genomic data derived from patients exhibiting immune evasion in lung cancer. This extensive analysis enabled them to uncover DDX54 as a significant factor underlying the resistance to immunotherapy. Their findings indicate that by targeting DDX54, it may be possible to overcome the barrier of immunotherapy resistance, effectively enhancing patient outcomes in previously difficult-to-treat lung tumors.
The research employed advanced systems biology techniques, allowing the team to integrate various high-dimensional data sets to build gene regulatory networks. The identification of DDX54 as a central regulator offers a prospective therapeutic target that could revolutionize the approach to treating this disease. In preclinical trials using a syngeneic mouse model, the suppression of DDX54 resulted in substantial increases in the infiltration of T cells and natural killer (NK) cells, key players in the body’s anti-cancer immune response. Furthermore, this suppression drastically improved the overall response to immunotherapy treatments.
Subsequent experiments employing single-cell transcriptomic and spatial transcriptomic analyses confirmed the effectiveness of targeting DDX54. The combination of DDX54 inhibition with immunotherapy led to encouraging results, with enhanced differentiation of T cells and memory T cells, which are crucial for long-term tumor suppression. Notably, the combination treatment reduced the presence of regulatory T cells and exhausted T cells that typically foster tumor growth.
The mechanisms underlying these changes appear to involve DDX54’s influence on critical signaling pathways, including JAK-STAT, MYC, and NF-κB. This regulatory cascade not only leads to the downregulation of immune-evasive proteins such as CD38 and CD47 but also affects the infiltration of immune cell populations that are pivotal to anti-tumor activity. The findings highlight the potential of DDX54 suppression to alter the tumor microenvironment in a manner conducive to successful immunotherapy.
Professor Cho articulated the significance of their findings by stating that they have, for the first time, identified a master regulatory factor capable of orchestrating immune evasion in lung cancer cells. He emphasized that targeting this factor could lead to a groundbreaking therapeutic strategy aimed at enhancing immune responsiveness in otherwise resistant cancer phenotypes. Through systematic integration of systems biology, combining information technology with biotechnological insights, the research team was able to reveal DDX54’s hidden roles within the complex molecular networks of cancer cells.
The implications of such discoveries are profound, not only for lung cancer treatment but also for potentially broadening the scope of effective immunotherapies across various cancer types. By inducing an immune-activated environment that restores the ability of immune cells to infiltrate cancer tissues, the combination therapy utilizing DDX54 inhibition could substantially enhance the sensitivity of tumors to immunotherapy, particularly in resistant cases.
As research continues into the biological intricacies of cancer-resistance mechanisms, the identification and targeting of key regulatory factors such as DDX54 offer hope for improved therapeutic strategies that leverage the body’s own immune system. The innovative approach adopted by the KAIST research team serves as a beacon for future studies that seek to unravel the complexities of tumor immunology and provide tangible benefits to patients grappling with cancer.
The study culminated in significant peer-reviewed publication in the Proceedings of the National Academy of Sciences on April 2, 2025, highlighting the contributions of Jeong-Ryeol Gong as the first author and Jungeun Lee as a co-first author, with Younghyun Han also contributing to the research effort. With backing from the Ministry of Science and ICT and the National Research Foundation of Korea, the work exemplifies a successful marriage of fundamental research and clinical application, a necessary pathway toward future breakthroughs in cancer treatment technologies.
Driven by a commitment to transform cancer treatment paradigms, this study stands as a testament to the continuing evolution of cancer research, presenting the scientific community with one more piece in the ever-complex puzzle of immunotherapy efficacy and resistance.
Subject of Research: Animal tissue samples
Article Title: DDX54 downregulation enhances anti-PD1 therapy in immune-desert lung tumors with high tumor mutational burden
News Publication Date: 2-Apr-2025
Web References: DOI
References: None available
Image Credits: KAIST Laboratory for Systems Biology and Bio-Inspired Engineering
Keywords: DDX54, immunotherapy, lung cancer, tumor mutational burden, immune checkpoint inhibitors, cancer treatment, systems biology, RNA-binding protein
