Bicompartmental Nanoparticles Overcome Drug Incompatibility to Eradicate Glioma and Induce Long-Lasting Immunological Memory

Combination therapies are a powerful strategy against complex and biologically heterogeneous diseases like high-grade glioma (HGG), but co-formulating chemically distinct drugs into a single delivery vehicle remains a formidable challenge. Here, we introduce a first-of-its-kind bicompartmental synthetic protein nanoparticle (biSPNP) platform that directly addresses this barrier. SPNPs physically separate and deliver two active agents with opposing physico-chemical properties: the hydrophobic microtubule-stabilizing chemotherapeutic paclitaxel (PTX), and a hydrophilic biologic, siRNA targeting the oncogenic transcription factor STAT3 (STAT3i). These biSPNPs, prepared via electrohydrodynamic co-jetting, measure 159 ± 42 nm in diameter and feature a negative zeta-potential of -18.7± 1.6 mV. Advanced super-resolution microscopy confirms the preservation of the hemispherical architecture even in liquid formulations. The unique bicompartmental design enables tailored, sequential drug release, with a rapid initial release of STAT3i followed by sustained PTX release. This combination therapy is designed to address cancer heterogeneity in high-grade glioma through a two-pronged insult, which induces direct cytotoxicity while simultaneously dismantling a key immunosuppressive signaling pathway. In intracranial HGG models, STAT3i/PTX biSPNPs, in combination with ionizing radiation, significantly improved median survival, with 50% of the mice being brain cancer-free 60 days after treatment. Histopathological and immunohistochemical analyses of the brain architecture of long-term survivors of the STAT3i/PTX biSPNPs treatment group showed no tumor burden, preservation of myelin integrity, and reduced astrocytic activation. Strikingly, survivors developed robust and long-lasting immunological memory, successfully rejecting tumor rechallenge without further treatment. These in vivo findings have been corroborated by in vitro studies demonstrating highly elevated levels of proimmunogenic cytokines, such as damage-associated molecular patterns (DAMPs) and Type 1 Interferons (IFNs). This work establishes bicompartmental protein nanoparticles as a breakthrough platform technology, fundamentally expanding the arsenal of drug combinations available for treatment of aggressive brain tumors.