ROS-sensitive PD-L1 siRNA cationic selenide nanogels for self-inhibition of autophagy and prevention of immune escape

In the field of cancer therapy,inhibiting autophagy has emerged as a promising strategy.However,pharmacological disruption of autophagy can lead to the upregulation of programmed death-ligand 1(PD-L1),enabling tumor immune evasion.To address this issue,we developed innovative ROS-responsive cationic poly(ethylene imine)(PEI)nanogels using selenol chemistry-mediated multicomponent reaction(MCR)technology.This procedure involved simple mixing of low-molecular-weight PEI(LMW PEI),γ-selenobutylacetone(γ-SBL),and poly(ethylene glycol)methacrylate(PEGMA).Through high-throughput screening,we constructed a library of AxSeyOz nanogels and identified the optimized A1.8Se3O0.5/siPD-L1 nanogels,which exhibited a size of approximately 200 nm,excellent colloidal stability,and the most effective PD-L1 silencing efficacy.These nanogels demonstrated enhanced uptake by tumor cells,excellent oxidative degradation ability,and inhibited autophagy by alkalinizing lysosomes.The A1.8Se3O0.5/siPD-L1 nanogels significantly downregulated PD-L1 expression and increased the expression of major histocompatibility complex class I(MHC-I),resulting in robust proliferation of specific CD8+T cells and a decrease in MC38 tumor growth.As a result,the A1.8Se3O0.5/siPD-L1 nanogels inhibited tumor growth through self-inhibition of autophagy,upregulation of MHC-I,and downregulation of PD-L1.Designed with dynamic diselenide bonds,the A1.8Se3O0.5/siPD-L1 nanogels showed synergistic antitumor efficacy through self-inhibition of autophagy and prevention of immune escape.

Cleavable bimetallic-organic polymers for ROS mediated cascaded cancer therapy under the guidance of MRI through tumor hypoxia relief strategy

Despite recent advances in tumor treatment, reactive oxygen species(ROS)-mediated therapy, such as photodynamic therapy(PDT) and chemical dynamic therapy(CDT), remains challenging mainly due to hypoxia in tumor microenviroment. Relieving the hypoxia of tumor tissue has been considered as an attractive strategy for enhancing efficacy of ROS-based cancer treatment.Herein, one cascaded platform was developed to overcome tumor hypoxia and synergistically enhance the effect of ROSmediated therapy. This platform is based on cleavable bimetallic metal organic polymers(DOX@Fe/Mn-THPPTK-PEG). As an efficient Fenton-like material, it could not only produce cytotoxic ·OH by catalyzing the decomposition of intracellular H2O2, but also generate O2 to alleviate tumor hypoxia. In addition, the DOX-loaded metal organic polymers(MOPs could be disrupted after being exposed to laser irradiation or/and treated with H2O2, and then release the DOX for chemotherapy. Overall, 3 therapies(hypoxia-relieved PDT, photo-enhanced CDT, and ROS-mediated chemotherapy) could be achieved simultaneously by such a smart platform. Furthermore, T1-weighted MRI imaging ability of the MOPs could be greatly improved under H2O2 treatment.Therefore, total four robust functions were realized in a simple platform. These findings demonstrate great clinical potentials of the MOPs for cancer theranostics.

Development and Application of a Mitochondrial Genetically Encoded Voltage Indicator in Narcosis

Mitochondrial membrane potential(MMP)plays a crucial role in the function of cells and organelles,involving various cellular physiological processes,including energy production,formation of reactive oxygen species(ROS),unfolded protein stress,and cell survival.Currently,there is a lack of genetically encoded fluorescence indicators(GEVIs)for MMP.In our screening of various GEVIs for their potential monitoring MMP,the Accelerated Sensor of Action Potentials(ASAP)demonstrated optimal performance in targeting mitochondria and sensitivity to depolarization in multiple cell types.However,mitochondrial ASAPs also displayed sensitivity to ROS in cardiomyocytes.Therefore,two ASAP mutants resistant to ROS were generated.A double mutant ASAP3-ST exhibited the highest voltage sensitivity but weaker fluorescence.Overall,four GEVIs capable of targeting mitochondria were obtained and named mitochondrial potential indicators 1-4(MPI-1-4).In vivo,fiber photometry experiments utilizing MPI-2 revealed a mitochondrial depolarization during isoflurane-induced narcosis in the M2 cortex.

Combining immune checkpoint blockade with ATP-based immunogenic cell death amplifier for cancer chemo-immunotherapy

Amplifying“eat me signal”during tumor immunogenic cell death(ICD)cascade is crucial for tumor immunotherapy.Inspired by the indispensable role of adenosine triphosphate(ATP,a necessary“eat me signal”for ICD),a versatile ICD amplifier was developed for chemotherapy-sensitized immunotherapy.Doxorubicin(DOX),ATP and ferrous ions(Fe^(2+))were co-assembled into nanosized amplifier(ADO-Fe)throughπ‒πstacking and coordination effect.Meanwhile,phenylboric acid-polyethylene glycol-phenylboric acid(PBA-PEG-PBA)was modified on the surface of ADO-Fe(denoted as PADO-Fe)by the virtue of d-ribose unit of ATP.PADO-Fe could display active targetability against tumor cells via sialic acid/PBA interaction.In acidic microenvironment,PBA-PEG-PBA would dissociate from amplifier.Moreover,high H_(2)O_(2)concentration would induce hydroxyl radical(·OH)and oxygen(O_(2))generation through Fenton reaction by Fe^(2+).DOX and ATP would be released from the amplifier,which could induce ICD effect and“ICD adjuvant”to amplify this process.Together with programmed death ligands 1(PD-L1)checkpoint blockade immunotherapy,PADO-Fe could not only activate immune response against primary tumor,but also strong abscopal effect against distant tumor.Our simple and multifunctional ICD amplifier opens a new window for enhancing ICD effect and immune checkpoint blockade therapy.