Transdermal Delivery of Poly-Hyaluronic Acid-Based Spherical Nucleic Acids for Chemogene Therapy

Spherical nucleic acid (SNA), as a good gene delivery system, has a good application prospect for transdermal administration in skin disorders treatment. However, most of traditional SNA core materials are...

Drug-Loaded Liposomal Spherical Nucleic Acid as an Effective Cancer Nanovaccine

Background: Cancer nanovaccine has become a promising approach for cancer immunotherapy. The major challenge of cancer vaccines is limited efficacy caused by lack of desirable tumor specific antigens (TSA). Chemotherapeutics can trigger immunogenic cell death (ICD) and release TSAs, which initiate tumor-specific immune responses. However, ICD-triggered immune responses are usually not potent enough to eliminate the tumor cells. Herein, we developed liposomal spherical nucleic acids (SNA) that can simultaneously deliver and release doxorubicin (DOX) and CpG oligonucleotides upon biological stimuli in tumors to augment antitumor immune responses. Results: SNA nanoparticle increased DOX accumulation at the tumor tissue to induce tumor cells apoptosis and autophagy to activate both ICD-triggered and autophagy-mediated Th1-type immune responses. Meanwhile, CpG, which was co-delivered with DOX, functioned synergistically to potentiate the antitumor immune responses. These nanoparticles effectively inhibited tumor growth and extended animal survival of a mouse lymphoma model. Conclusions: This work provided a simple strategy of delivering chemotherapeutics and adjuvants to tumors to improve immunotherapeutic efficacy of nanovaccines.

IMMU-53. STING-ING GLIOBLASTOMA WITH SPHERICAL NUCLEIC ACIDS

The Stimulator of Interferon Genes (STING) pathway represents a major innate immune sensing mechanism for tumor-derived DNA. Modified cyclic dinucleotides (CDNs) that mimic the endogenous STING ligand cGAMP are currently being explored in patients with solid tumors that are amenable to intratumoral delivery. Inadequate bioavailability and insufficient lipophilicity are limiting factors for clinical CDN development, in particular when consideration is given to systemic administration approaches. We have shown that the formulation of oligonucleotides into Spherical Nucleic Acid (SNA) nanostructures, i.e.,the presentation of oligonucleotides at high density on the surface of nanoparticle cores, lead to biochemical and biological properties that are radically different from those of linear oligonucleotides. First-generation brain-penetrant siRNA-based SNAs (NCT03020017, recurrent GBM) have recently completed early clinical trials. Here, we report the development of a STING-agonistic immunotherapy by targeting cGAS, the sensor of cytosolic dsDNA upstream of STING, with SNAs presenting dsDNA at high surface density. The strategy of using SNAs exploits the ability of cGAS to raise STING responses by delivering dsDNA and inducing the catalytic production of endogenous CDNs. SNA nanostructures carrying a 45bp IFN-simulating dsDNA oligonucleotide, the most commonly used and widely characterized cGAS activator, potently activated the cGAS-STING pathway in vitro and in vivo. In a poorly immunogenic and highly aggressive syngeneic mouse glioma model, in which tumours were well-established, only one dose of intranasal treatment with STING-SNAs decelerated tumour growth, improved survival and importantly, was well-tolerated. Our use of SNAs addresses the challenges of nucleic acid delivery to intracranial tumor sites via intranasal route, exploits the binding of dsDNA molecules on the SNA surface to enhance the formation of a dimeric cGAS:DNA complex and establishes cGAS-agonistic SNAs as a novel class of immune-stimulatory modalities for triggering innate immune responses against tumor.