PlP-driven exosomal breakthroughs: Advancing immune solutions for complex tumor microenvironments.

e14511 Background: The tumor microenvironment (TME) represents a critical barrier in oncology therapy due to its ability to suppress immune responses, facilitate tumor progression, and promote resistance to treatment. Exosomes derived from dendritic cells pre-conditioned (EDCD-PC) with the Phospholipoproteomic Complex (PLP) offer a transformative therapeutic platform for TME reprogramming. These exosomes deliver bioactive molecules that modulate key immune and metabolic pathways, helping to restore a pro-inflammatory balance while reducing immunosuppressive signaling within the TME. This innovative approach not only addresses the needs of pediatric, adolescent, young adult, and elderly patients with highly aggressive and therapy-resistant tumors but also ensures global scalability through technological stabilization. Using lyophilization, EDCD-PC exosomes achieve stability and bioactivity without cold chain logistics, enabling broader application and reducing logistical challenges in resource-limited settings. Methods: Semi-immortalized dendritic cells were pre-conditioned with PLP (50 µg/mL) for 24 hours before secretome extraction. The derived exosomes were lyophilized with advanced cryoprotectants and characterized by NanoSight (size and concentration) and Western Blot (CD63, TSG101). AGS (gastric) and A375 (melanoma) tumor cell lines were treated with concentrations of 10, 50, and 100 µg/mL for 72 hours. Key cytokines (IL-10, TGF-β, IFN-γ) were measured by Cytometric Bead Array (CBA), apoptosis was assessed by Annexin V/PI staining, and caspase-3 activation was analyzed. Results: Functional Stability: Lyophilized EDCD-PC maintained 92.3% ± 1.2 functionality after 6 months at 4°C. Modulation of TME: Reduction of immunosuppressive cytokines: IL-10 (-41.8%, p < 0.01) and TGF-β (-38.6%, p < 0.01); Increase in pro-inflammatory cytokines: IFN-γ (+54.2%, p < 0.001) and TNF-α (+52.8%, p < 0.001). Tumor Apoptosis: 47.1% ± 2.3 apoptosis in A375 and 44.7% ± 1.8 in AGS (p < 0.01). Conclusions: Pre-conditioning dendritic cells with PLP enhances the quality and efficacy of derived exosomes, providing a scalable solution for TME reprogramming. Lyophilization ensures global applicability by preserving bioactivity while eliminating cold chain requirements. This advancement allows advanced therapies to reach underserved populations. EDCD-PC exosomes effectively modulate the TME by reducing immunosuppressive cytokines and enhancing pro-inflammatory responses, facilitating tumor regression. Their apoptosis-inducing properties in aggressive tumor cells emphasize their value as a targeted tool in oncology. This approach offers a practical path for personalized cancer care across diverse demographics, particularly for patients with limited treatment options.