(146d) Delivery of Engineered Cytokine Construct mRNA Via Layered Lipid Nanoparticles

High-grade serous ovarian cancer (HGSOC) is the most prevalent form of ovarian cancer and the deadliest gynecological malignancy, with most diagnoses occurring at stage III or IV. Though approximately 80% of patients initially respond well to the standard clinical treatment of debulking surgery followed by platinum-based chemotherapy, most will experience a relapse of the primary tumor or tumor metastases, resulting in a 5-year survival rate of around 30%. Immunotherapies, particularly immune checkpoint inhibitors (CPI), which have shown promising responses in other types of cancer such as melanoma, are ineffective in HGSOC due to low lymphocyte infiltration in the tumor microenvironment (TME). Recent studies have demonstrated the potential of cytokine-mediated immune activation for inflaming the TME with activated lymphocytes. Interleukin 12 (IL-12) can induce immunogenic cell death, activate NK cells, convert M2 macrophages to the pro-inflammatory M1 state, and promote the downstream production of interferon (IFN)-γ; however, it has resulted in patient deaths in clinical trials. Therefore, novel methods for delivering cytokines or modifying the protein could enhance the effectiveness of these treatments and immunotherapies.

In this work, layered lipid nanoparticles (LLNPs) are utilized to deliver mRNA encoding for a targeted cytokine construct to enhance the effects of IL-12 in HGSOC. First, IL-12 is linked to an aCD45 VHH to reduce leakage of the cytokine into the blood and increase cytokine trafficking from the immune-cold TME to the tumor-draining lymph nodes (TDLNs). This construct is packaged into an mRNA and encapsulated into a lipid nanoparticle coated with a targeting polymer on the surface using layer-by-layer technology. Layering using the polyanion poly-L-glutamic acid (PLE) increases the localization of the LLNPs to cancer cells and the transfection of the mRNA in the targeted cells. The optimized PLE LLNP IL-12 therapy leads to increased immune infiltration into the TME, enhances the trafficking of the cytokine to the TDLNs, and sensitizes mice to CPI, resulting in a promising curative approach for HGSOC.