DNA has emerged as a versatile and powerful tool in the field of cancer immunotherapy, offering unique advantages due to its programmable structure, biocompatibility, and multifunctional capabilities. Among the various forms of DNA-based materials, functional immunostimulating DNA constructs are gaining increasing attention as promising candidates for modulating immune responses against tumors. These materials leverage the intrinsic immunogenic properties of specific DNA sequences or their ability to deliver therapeutic payloads with high precision, thereby enhancing antitumor immunity. This review focuses on recent advances in immunostimulating DNA materials, particularly those targeting Toll-like receptor 9 (TLR9), immune checkpoint receptors via DNA aptamers, and strategies that physically bridge immune and tumor cells through DNA hybridization or aptamer-ligand interactions.
One of the most well-established mechanisms of DNA-mediated immune activation involves unmethylated CpG motifs—short DNA sequences rich in cytosine-guanine dinucleotides—that mimic microbial DNA. These motifs are recognized by TLR9, primarily expressed in plasmacytoid dendritic cells and B cells, triggering downstream signaling cascades involving MyD88, which leads to the production of pro-inflammatory cytokines such as TNF-α, IL-6, and IL-12. This results in the maturation and activation of antigen-presenting cells, ultimately promoting both innate and adaptive immune responses. However, naked CpG oligonucleotides are rapidly degraded by nucleases in biological environments, limiting their efficacy. To overcome this challenge, researchers have integrated CpG motifs into various DNA nanostructures, including tetrahedrons, dendrimers, origami tubes, hydrogels, nanocentipedes, and nanoflowers. These nanostructures not only protect CpG motifs from degradation but also enhance cellular uptake and multivalent delivery, significantly amplifying immune stimulation. For example, CpG-loaded DNA tetrahedrons showed enhanced stability and robust cytokine secretion in macrophages, while DNA nanoflowers demonstrated superior resistance to nucleases and potent induction of TNF and IL-6. Moreover, stimuli-responsive systems such as inflammation-triggered nanococoons and i-motif-based hydrogels enable controlled release of CpG motifs within the tumor microenvironment, improving therapeutic precision.
Another exciting frontier lies in the use of DNA aptamers—synthetic single-stranded oligonucleotides capable of folding into complex 3D structures that bind specifically to target molecules with high affinity. Unlike antibodies, DNA aptamers offer smaller size, lower immunogenicity, easier synthesis, and greater stability. In cancer immunotherapy, they have been employed to target key immune checkpoint proteins such as PD-1, PD-L1, and CTLA-4. For instance, PD-1-targeting DNA aptamers were shown to restore T cell proliferation and IL-2 secretion, effectively inhibiting tumor growth in murine models. Similarly, PD-L1-specific aptamers blocked the PD-1/PD-L1 axis and enhanced T cell infiltration into tumors. Notably, these aptamers can be delivered using polyaptamer hydrogels or DNA nanostructures, enabling sustained release and improved pharmacokinetics. Furthermore, dual-functional aptamer systems—such as those combining PD-L1 targeting with NK cell engagement—have demonstrated synergistic effects, enhancing tumor cell recognition and lysis. Such innovations highlight the potential of DNA aptamers to serve as next-generation alternatives to monoclonal antibodies in checkpoint blockade therapy.
Beyond direct molecular targeting, DNA-based materials are being used to engineer spatial interactions between immune and cancer cells. By surface-modifying immune cells with complementary DNA strands or aptamers, researchers can induce physical clustering of immune and tumor cells, increasing the likelihood of immune synapse formation. Methods such as hydrophobic insertion of cholesterol-conjugated DNA into cell membranes allow for stable, non-toxic surface engineering without disrupting cellular functions. Examples include DNA aptamer-functionalized natural killer (NK) cells that efficiently capture and kill tumor cells, and DNA origami-guided assemblies that facilitate gap junction formation and intercellular communication.LAL Antibody supplier These approaches not only improve recognition but also boost effector functions, such as cytokine release and cytotoxic granule delivery.CBX4 Antibody MedChemExpress Additionally, DNA hybridization-based scaffolds have enabled precise spatial organization of immune and tumor cells in pre-designed clusters, leading to enhanced killing efficiency and durable antitumor responses.PMID:35044691
Despite significant progress, several challenges remain before clinical translation. The instability of free DNA in vivo remains a major hurdle, necessitating advanced chemical modifications or nanoformulations for protection. Improving the binding affinity of DNA aptamers through more rigorous SELEX protocols is crucial for achieving therapeutic efficacy comparable to antibodies. Moreover, while many studies demonstrate strong in vitro activity, in vivo validation under complex tumor microenvironments is still limited. Future research should focus on developing smart, responsive DNA platforms that integrate multiple functionalities—immune stimulation, checkpoint inhibition, and targeted delivery—within a single system. Combining DNA-based immunomodulation with other therapies, such as chemotherapy or CAR-T cell therapy, may further amplify antitumor outcomes.
In conclusion, functional immunostimulating DNA materials represent a transformative approach in cancer immunotherapy. Their programmability, versatility, and compatibility with living systems position them at the forefront of next-generation immunoengineering. As research continues to address current limitations, these materials hold immense promise for developing safer, more effective, and personalized cancer treatments.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com