Immunotherapy
is emerging as a paradigm-shifting modality for treatment
cancer. However, systemic administration of immunomodulators is usually
accompanied by extra-tumor toxicity and adverse immune effects. Precise
delivery of immunomodulators with a highly controllable system may
provide a solution for this issue. Here, we developed a photocontrolled
DNA nanomedicine for localized delivery of DNA immunomodulators to
enhance membrane-targeted photodynamic immunotherapy. Specifically,
the DNA nanomedicine is composed of long tandemly repeated functional
DNA sequences (PDL1 aptamers and CpG) with a photosensitizer (TMPyP4) inserted into the DNA structure, providing high drug-loading
capacity. By blocking the surface PDL1 aptamer with a pHLIP-modified
cDNA, the DNA nanomedicine does not induce any obvious immune response
and can be specifically delivered and anchored to the tumor membrane.
Under localized irradiation, photodynamically generated reactive oxygen
species (ROS) causes breakage of DNA sequences, which triggers the
collapse of the nanostructure and release of internal DNA immunomodulators.
Under localized illumination, photodynamically generated ROS can cause
DNA sequence breaks, triggering the collapse of nanostructures and
the release of internal DNA immunomodulators thus enhancing membrane-targeted
photodynamic immunotherapy. We have demonstrated that the developed
DNA nanomedicine can drive efficient immune responses in tumor tissue
without perceptibly interfering off-tumor immunity, resulting in efficient
antitumor treatment while mitigating systemic toxicity.