RNA aggregates harness the danger response for potent cancer immunotherapy.

Cancer immunotherapy remains limited by poor antigenicity and a regulatory tumor microenvironment (TME). Here, we create "onion-like" multi-lamellar RNA lipid particle aggregates (LPAs) to substantially enhance the payload packaging and immunogenicity of tumor mRNA antigens. Unlike current mRNA vaccine designs that rely on payload packaging into nanoparticle cores for Toll-like receptor engagement in immune cells, systemically administered RNA-LPAs activate RIG-I in stromal cells, eliciting massive cytokine/chemokine response and dendritic cell/lymphocyte trafficking that provokes cancer immunogenicity and mediates rejection of both early- and late-stage murine tumor models. In client-owned canines with terminal gliomas, RNA-LPAs improved survivorship and reprogrammed the TME, which became "hot" within days of a single infusion. In a first-in-human trial, RNA-LPAs elicited rapid cytokine/chemokine release, immune activation/trafficking, tissue-confirmed pseudoprogression, and glioma-specific immune responses in glioblastoma patients. These data support RNA-LPAs as a new technology that simultaneously reprograms the TME while eliciting rapid and enduring cancer immunotherapy.

mRNA aggregates harness danger response for potent cancer immunotherapy.

Messenger RNA (mRNA) has emerged as a remarkable tool for COVID-19 prevention but its use for induction of therapeutic cancer immunotherapy remains limited by poor antigenicity and a regulatory tumor microenvironment (TME). Herein, we develop a facile approach for substantially enhancing immunogenicity of tumor-derived mRNA in lipid-particle (LP) delivery systems. By using mRNA as a molecular bridge with ultrapure liposomes and foregoing helper lipids, we promote the formation of 'onion-like' multi-lamellar RNA-LP aggregates (LPA). Intravenous administration of RNA-LPAs mimics infectious emboli and elicits massive DC/T cell mobilization into lymphoid tissues provoking cancer immunogenicity and mediating rejection of both early and late-stage murine tumor models. Unlike current mRNA vaccine designs that rely on payload packaging into nanoparticle cores for toll-like receptor engagement, RNA-LPAs stimulate intracellular pathogen recognition receptors (RIG-I) and reprogram the TME thus enabling therapeutic T cell activity. RNA-LPAs were safe in acute/chronic murine GLP toxicology studies and immunologically active in client-owned canines with terminal gliomas. In an early phase first-in-human trial for patients with glioblastoma, we show that RNA-LPAs encoding for tumor-associated antigens elicit rapid induction of pro-inflammatory cytokines, mobilization/activation of monocytes and lymphocytes, and expansion of antigen-specific T cell immunity. These data support the use of RNA-LPAs as novel tools to elicit and sustain immune responses against poorly immunogenic tumors.

Angiotensin-converting enzyme DD genotype in patients with primary pulmonary hypertension: increased frequency and association with preserved haemodynamics.

UNLABELLED: HYPOTHESIS/INTRODUCTION: A polymorphic marker within the angiotensin- converting enzyme (ACE) gene has been associated with circulating and tissue ACE activity and with a variety of forms of cardiovascular disease. Since angiotensin II (Ang II) causes pulmonary vasoconstriction and vascular and myocardial remodelling, we postulated a role for the renin-angiotensin system and the ACE DD genotype in the pathophysiology of primary pulmonary hypertension (PPH) and in the right ventricular response to pressure overload in these patients. METHODS AND RESULTS: The incidence of the ACE DD genotype was evaluated in 60 patients with severe PPH compared with two normal control populations, a group of healthy population-based controls (n=158) and subjects found suitable for cardiac organ donation (n=79). Genomic DNA extracted from peripheral leukocytes was amplified using the polymerase chain reaction to detect polymorphic markers. Haemodynamics were determined by right heart catheterisation in a subset of the PPH patients. The frequency of the ACE DD genotype was 45% in the patients with PPH, compared with 24% in the organ donors, and 28% in population-based healthy controls (p=0.01 for chi-square test). Of the 32 PPH patients with baseline haemodynamics, 12 exhibited the ACE DD genotype and 20 were non-DD. While the mean pulmonary artery pressure and the duration of symptoms attributable to pulmonary hypertension was not different between the DD and non-DD groups, cardiac output was significantly lower (3.29+0.27 vs. 5.07+0.37 L/minute, p=0.002) and the mean right atrial pressure tended to be higher (8.85+1.29 vs. 4.92+1.27 mmHg, p=0.08) in the non-DD group. The reduction in cardiac output seen in the non-DD group was not due to a difference in heart rate, but to a significant reduction in stroke volume, consistent with a decreased contractile state. In addition, non-DD patients exhibited a significantly worse functional capacity (NYHA Class 3.14+0.12 vs. 2.40+0.28, p=0.02). CONCLUSIONS: 1) The ACE DD genotype is significantly increased in patients with severe PPH compared with normal controls, suggesting that certain individuals may be genetically predisposed to developing pulmonary hypertension. 2) The ACE DD genotype is associated with preserved right ventricular function in PPH patients, supporting a compensatory myocardial or inotropic role for Ang II in the pressure overloaded right ventricle.