Inhibition of glycolysis-driven immunosuppression with a nano-assembly enhances response to immune checkpoint blockade therapy in triple negative breast cancer

Immune-checkpoint inhibitors (ICI) are promising modalities for treating triple negative breast cancer (TNBC). However, hyperglycolysis, a hallmark of TNBC cells, may drive tumor-intrinsic PD-L1 glycosylation and boost regulatory T cell function to impair ICI efficacy. Herein, we report a tumor microenvironment-activatable nanoassembly based on self-assembled aptamer-polymer conjugates for the targeted delivery of glucose transporter 1 inhibitor BAY-876 (DNA-PAE@BAY-876), which remodels the immunosuppressive TME to enhance ICI response. Poly β-amino ester (PAE)-modified PD-L1 and CTLA-4-antagonizing aptamers (aptPD-L1 and aptCTLA-4) are synthesized and co-assembled into supramolecular nanoassemblies for carrying BAY-876. The acidic tumor microenvironment causes PAE protonation and triggers nanoassembly dissociation to initiate BAY-876 and aptamer release. BAY-876 selectively inhibits TNBC glycolysis to deprive uridine diphosphate N-acetylglucosamine and downregulate PD-L1 N-linked glycosylation, thus facilitating PD-L1 recognition of aptPD-L1 to boost anti-PD-L1 therapy. Meanwhile, BAY-876 treatment also elevates glucose supply to tumor-residing regulatory T cells (Tregs) for metabolically rewiring them into an immunostimulatory state, thus cooperating with aptCTLA-4-mediated immune-checkpoint inhibition to abolish Treg-mediated immunosuppression. DNA-PAE@BAY-876 effectively reprograms the immunosuppressive microenvironment in preclinical models of TNBC in female mice and provides a distinct approach for TNBC immunotherapy in the clinics.

Small extracellular vesicles delivering lncRNA WAC-AS1 aggravate renal allograft ischemia‒reperfusion injury by inducing ferroptosis propagation

Ferroptosis is a predominant contributor to renal ischemia reperfusion injury (IRI) after kidney transplant, evoking delayed graft function and poorer long-term outcomes. The wide propagation of ferroptosis among cell populations in a wave-like manner, developing the "wave of ferroptosis" causes a larger area of tubular necrosis and accordingly aggravates renal allograft IRI. In this study, we decipher a whole new metabolic mechanism underlying ferroptosis and propose a novel spreading pathway of the "wave of ferroptosis" in the renal tissue microenvironment, in which renal IRI cell-secreted small extracellular vesicles (IRI-sEVs) delivering lncRNA WAC-AS1 reprogram glucose metabolism in adjacent renal tubular epithelial cell populations by inducing GFPT1 expression and increasing hexosamine biosynthesis pathway (HBP) flux, and consequently enhances O-GlcNAcylation. Additionally, BACH2 O-GlcNAcylation at threonine 389 in renal tubular epithelial cells prominently inhibits its degradation by ubiquitination and promotes importin α5-mediated nuclear translocation. We present the first evidence that intranuclear BACH2 suppresses SLC7A11 and GPX4 transcription by binding to their proximal promoters and decreases cellular anti-peroxidation capability, accordingly facilitating ferroptosis. Inhibition of sEV biogenesis and secretion by GW4869 and knockout of lncRNA WAC-AS1 in IRI-sEVs both unequivocally diminished the "wave of ferroptosis" propagation and protected against renal allograft IRI. The functional and mechanistic regulation of IRI-sEVs was further corroborated in an allograft kidney transplant model and an in situ renal IRI model. In summary, these findings suggest that inhibiting sEV-mediated lncRNA WAC-AS1 secretion and targeting HBP metabolism-induced BACH2 O-GlcNAcylation in renal tubular epithelial cells may serve as new strategies for protecting against graft IRI after kidney transplant.