Targeted Delivery of miRNA 155 to Tumor Associated Macrophages for Tumor Immunotherapy.

Tumor associated macrophages (TAMs) are important components residing in the tumor microenvironment. They are immunosuppressive and promote tumor progression. Targeting TAMs and reprogramming their phenotype may be a promising strategy that can restore antitumor immune responses. In this study, we developed a microRNA delivery system based on lipid-coated calcium phosphonate nanoparticles (CaP/miR@pMNPs) containing conjugated mannose and sterically shielded with a pH-responsive material. The nanocarrier could respond to the low pH in the tumor microenvironment and expose mannose to promote cellular internalization in TAMs. The carrier could reactivate TAMs and reprogram their functions, reverse the immunosuppressive tumor microenvironment, and inhibit tumor growth in a tumor-bearing mouse model. In summary, redirecting the polarization of TAMs is a potential therapeutic strategy for tumor immunotherapy.

Targeted Delivery of Zoledronate to Tumor-Associated Macrophages for Cancer Immunotherapy.

Tumor-associated macrophages (TAMs) are recruited from circulatory monocytes by tumor-derived factors, which differentiate into macrophages residing in the tumor microenvironment. TAMs play critical roles in promoting angiogenesis, invasion, metastasis and immune escape, and the direct depletion of TAMs is a promising strategy for tumor immunotherapy. In this study, we developed lipid-coated calcium zoledronate nanoparticles (CaZol@pMNPs) containing conjugated mannose, which were sterically shielded with an extracellular pH-sensitive material. The NPs specifically targeted TAMs and induced their apoptosis in vitro and in vivo. In a S180 tumor-bearing mouse model, CaZol@pMNPs effectively depleted TAMs, markedly decreased angiogenesis, reduced immune suppression, and eventually restrained tumor growth without eliciting systemic effects. The collective data indicate the potential of the direct depletion of TAMs using CaZol@pMNPs for cancer immunotherapy.

Tailored Polymers with Complement Activation Ability To Improve Antitumor Immunity.

The complement system plays an important role in host innate immunity, and its activation can be exploited as a potential strategy for vaccine adjuvants. Herein, a pH-responsive micellar vaccine platform (COOH-NPs) was developed using a carboxyl-modified diblock copolymer of poly(2-ethyl-2-oxazoline)-poly(d,l-lactide) (COOH-PEOz-PLA). The copolymer self-assembled into micelles with hydroxyl groups shielding on the surface, which activated the complement system for the enhanced immune responses. Compared with the control nanoparticles (OCH3-NPs), COOH-NPs significantly enhanced lymph node-resident dendritic cell maturation, antigen-specific IgG production, antigen-specific CD4+ and CD8+ T-cell activation, and the amount of memory T-cell generation in vivo. Furthermore, immunization with COOH-NPs/OVA in E.G7-OVA tumor-bearing mice not only remarkably inhibited tumor growth but also prolonged the survival of tumor-bearing mice. These results indicated that COOH-NPs with the capability of complement activation efficiently boosted the immune responses for the antitumor effect. The study demonstrated the significance of taking advantage of a complement-activating vaccine platform for cancer immunotherapy.

Rational Design of Multifunctional Polymeric Nanoparticles Based on Poly(l-histidine) and d-α-Vitamin E Succinate for Reversing Tumor Multidrug Resistance.

A multifunctional nanoparticulate system composed of methoxy poly(ethylene glycol)-poly(l-histidine)-d-α-vitamin E succinate (MPEG-PLH-VES) copolymers for encapsulation of doxorubicin (DOX) was elaborated with the aim of circumventing the multidrug resistance (MDR) in breast cancer treatment. The MPEG-PLH-VES nanoparticles (NPs) were subsequently functionalized with biotin motif for targeted drug delivery. The MPEG-PLH-VES copolymer exerts no obvious effect on the P-gp expression level of MCF-7/ADR but exhibited a significant influence on the loss of mitochondrial membrane potential, the reduction of intracellular ATP level, and the inhibition of P-gp ATPase activity of MCF-7/ADR cells. The constructed MPEG-PLH-VES NPs exhibited an acidic pH-induced increase on particle size in aqueous solution. The DOX-encapsulated MPEG-PLH-VES/biotin-PEG-VES (MPEG-PLH-VES/B) NPs were characterized to possess high drug encapsulation efficiency of approximate 90%, an average particle size of approximately 130 nm, and a pH-responsive drug release profile in acidic milieu. Confocal laser scanning microscopy (CLSM) investigations revealed that the DOX-loaded NPs resulted in an effective delivery of DOX into MCF-/ADR cells and a notable carrier-facilitated escape from endolysosomal entrapment. Pertaining to the in vitro cytotoxicity evaluation, the DOX-loaded MPEG-PLH-VES/B NPs resulted in more pronounced cytotoxicity to MCF-/ADR cells compared with DOX-loaded MPEG-PLH-VES NPs and free DOX solution. In vivo imaging study in MCF-7/ADR tumor-engrafted mice exhibited that the MPEG-PLH-VES/B NPs accumulated at the tumor site more effectively than MPEG-PLH-VES NPs due to the biotin-mediated active targeting effect. In accordance with the in vitro results, DOX-loaded MPEG-PLH-VES/B NPs showed the strongest inhibitory effect against the MCF-7/ADR xenografted tumors with negligible systemic toxicity, as evidenced by the histological analysis and change of body weight. The multifunctional MPEG-PLH-VES/B nanoparticulate system has been demonstrated to provide a promising strategy for efficient delivery of DOX into MCF-7/ADR cancerous cells and reversing MDR.

Poly(l-histidine) based triblock copolymers: pH induced reassembly of copolymer micelles and mechanism underlying endolysosomal escape for intracellular delivery.

Various poly(l-histidine) based amphiphilic copolymers have been developed for intracellular drug delivery due to the pH responsive properties and the escape from endolysosomal pathway. However, the pH induced reassembly of copolymer micelles and the assumed endolysosome membrane rupture during the copolymer facilitated endolysosomal escape have never been elucidated. To address these issues, a series of poly(ethylene glycol)-poly(d,l-lactide)-poly(l-histidine) (mPEG-PLA-PHis) with different degrees of polymerization of PLA and PHis block were synthesized. The self-assembly and reassembly behaviors of the copolymers were characterized using transmission electron microscopy (TEM), (1)H NMR, fluorescence probe technique, and dynamic light scattering (DLS). The copolymers self-assembled into micelles with PLA and unprotonated PHis blocks as hydrophobic core and PEG as hydrophilic shell at neutral pH. The changes in TEM images, (1)H NMR spectrum of PHis peak, pyrene fluorescene spectrum, and particle size as well as size distribution over the pH range from pH 8.5 to 4.5 suggest that the copolymer micelles reassembled into micelles with PLA as hydrophobic core and protonated PHis and PEG as hydrophilic shell under acidic environment. The pH induced reassembly triggered the incoporated doxorubicin (DOX) release, as indicated by the in vitro accelerated drug release and enhanced cytotoxicity. The integrity of endolysosome membrane during the copolymer facilitated DOX endolysosomal escape was observed by confocal laser scan microscopy (CLSM) and further evaluated by hemolysis test and calculation of the critical size of endolysosomal membrane. The results indicate that the endolysosomal membrane remained intact during the copolymer facilitated endolysosomal escape of DOX. It is more reasonable to ascribe the PHis based copolymer facilitation endolysosomal escape to the "proton sponge" hypothesis without rupturing the endolysosomal membrane.

Preparation, characterization, cellular uptake and evaluation in vivo of solid lipid nanoparticles loaded with cucurbitacin B.

In this work, solid lipid nanoparticles loaded with cucurbitacin B (Cu B-SLNs) were prepared. It was found that the concentration of poloxamer 188 and soybean lecithin had effects on the mean particle size and size distribution. The zeta potentials were around -33 mV. In vitro release studies showed a sustained release after a burst release. Internalization of Cu B into HepG2 cells could be enhanced by the encapsulation of SLN matrix. The IC50 values of Cu B-SLNs were lower than that of Cu B solution. Both free Cu B and Cu B-SLNs had effectively inhibited the tumor growth and displayed a dose-dependent anti-tumor efficacy. Cu B-SLNs at a dose of 0.11 mg/kg produced the greatest anti-tumor effects (53.3%), which was significant higher than Cu B solution (31.5%, p < 0.05). Cu B-SLNs showed a longer MRT in vivo. The AUC of Cu B-SLNs for tumor increased 3.5 -fold when compared to Cu B solution. The targeting efficiency of Cu B-SLNs was 1.94 times higher in liver as compared to that of Cu B solution. These results indicated that Cu-B SLNs could passively target the tumor with EPR effect, improve the therapeutic efficacy of Cu B, and reduce the doses.

[Progress in the study of targeted drug delivery systems for cancer stem cells].

The discovery, sorting and identification methods as well as targeted drug delivery systems for cancer stem cells (CSCs) have been reviewed by consulting the recent research papers. CSCs have been believed to be responsible for the occurrence and development of chemo-resistance, leading to the failure of chemotherapy. Much progress has been made in the approaches for CSCs targeting drug delivery systems. The understanding and targeted drug delivery systems for CSCs are promising to provide an alternative for cancer therapy.

Albumin-coated pH-responsive dimeric prodrug-based nano-assemblies with high biofilm eradication capacity.

Pseudomonas aeruginosa (PA) biofilms cause many persistent chronic infections in humans, especially in cystic fibrosis (CF) patients. The biofilms form a strong barrier which may inhibit antimicrobial agents from penetrating the biofilms and killing PA bacteria that reside deep within the biofilms. Concomitant therapies based on tobramycin (TOB) and azithromycin (AZM) have demonstrated beneficial effects in CF patients with chronic PA infections. However, the co-delivery of TOB and AZM has rarely been reported. In this study, we constructed a self-assembled pH-sensitive nano-assembly (DPNA) based on a dimeric prodrug (AZM-Cit-TOB) by simply inserting citraconic amide bonds between AZM and TOB. Moreover, the cationic surface of DPNA was further modified with anionic albumin (HSA) via electrostatic interactions to form an electrostatic complex (termed HSA@DPNA) for better biocompatibility. Upon arrival at the infected tissues, the citraconic amide bonds would be cleaved at acidic pH, resulting in the release of TOB and AZM for bacteria killing and biofilm eradication. As expected, HSA@DPNA showed comparable antibacterial abilities against the P. aeruginosa strain PAO1 in both planktonic and biofilm modes of growth compared to the TOB/AZM mixture in vitro. Moreover, HSA@DPNA exhibited excellent therapeutic efficacy on mice with PAO1-induced lung infection compared to the TOB/AZM mixture, and no detectable toxicity to mammalian cells/animals was observed during the therapeutic process. In summary, our study provides a promising method for the co-delivery of AZM and TOB in concomitant therapies against PAO1-related infection.

Reversing ferroptosis resistance by MOFs through regulation intracellular redox homeostasis.

As a non-apoptotic cell death form, ferroptosis offers an alternative approach to overcome cancer chemotherapy resistance. However, accumulating evidence indicates cancer cells can develop ferroptosis resistance by evolving antioxidative defense mechanisms. To address this issue, we prepared a Buthionine-(S,R)-sulfoximine (BSO) loaded metal organic framework (MOF) of BSO-MOF-HA (BMH) with the combination effect of boosting oxidative damage and inhibiting antioxidative defense. MOF nanoparticle was constructed by the photosensitizer of [4,4,4,4-(porphine-5,10,15,20-tetrayl) tetrakis (benzoic acid)] (TCPP) and the metal ion of Zr6, which was further decorated with hyaluronic acid (HA) in order to impart active targeting to CD44 receptors overexpressed cancer cells. BMH exhibited a negative charge and spherical shape with average particle size about 162.5 nm. BMH was found to restore the susceptibility of 4T1 cells to ferroptosis under irradiation. This was attributed to the combination of photodynamic therapy (PDT) and γ-glutamylcysteine synthetase inhibitor of BSO, shifting the redox balance to oxidative stress. Enhanced ferroptosis also induced the release of damage associated molecular patterns (DAMPs) to maturate dendritic cells and activated T lymphocytes, leading to superior anti-tumor performance in vivo. Taken together, our findings demonstrated that boosting oxidative damage with photosensitizer serves as an effective strategy to reverse ferroptosis resistance.

Stimuli-responsive nanoparticles delivered by a nasal-brain pathway alleviate depression-like behavior through extensively scavenging ROS.

Depression is one of the most common mental diseases, which seriously affects patients' physical and mental health. Emerging evidence has indicated that oxidative stress (OS) is a major cause of neurodegeneration involved in the pathogenesis of depression. Consequently, targeted reactive oxygen species (ROS) elimination is regarded as a promising strategy for efficient depression therapy. In addition, insufficient brain drug delivery is the main obstacle to depression therapy owing to the presence of the blood-brain barrier (BBB). To achieve the goals of bypassing the BBB and promoting antioxidant therapy for depression, a broad-spectrum ROS scavenging NPs was rationally designed through a nasal-brain pathway developed for combined ROS scavenging and brain drug delivery. A hexa-arginine (R6) modified ROS-responsive dextran (DEX) derivate was synthesized for antidepressant olanzapine (Olz) and H2 donor amino borane (AB) loading to prepare Olz/RDPA nanoparticles (NPs). Subsequently, the NPs were dispersed into a thermoresponsive hydrogel system based on poloxamer. In vitro and in vivo results demonstrated that Olz/RDPA in situ thermoresponsive hydrogel system could effectively deliver NPs to the brain via the nasal-brain pathway and alleviate depression-like behaviors through combined ROS depletion and inhibition of 5-HT dysfunction of the oxidative stress-induced. The proposed ROS-scavenging nanotherapeutic would open a new window for depression treatment. STATEMENT OF SIGNIFICANCE: ROS is an innovative therapeutic target involving the pathology of depression whereas targeted delivery of ROS scavenging has not been achieved yet. In the current study, ROS-responsive nanoparticles (Olz/RDPA NPs) were prepared and dispersed in a thermosensitive hydrogel for delivery through the nasal-brain pathway for the treatment of depression. Sufficient ROS depletion and improvement of delivery capacity by the nasal-brain pathway effectively could reverse oxidative stress and alleviate depressive-like behavior. Collectively, these nanoparticles may represent a promising strategy for the treatment of depression.

Blockage of the IDO1 pathway by charge-switchable nanoparticles amplifies immunogenic cell death for enhanced cancer immunotherapy.

Immunosuppressive tumor microenvironment (ITM), poor immunogenicity, and low tumor penetration markedly reduce the capability of tumor immunotherapy. To address these challenges, we successfully engineered acidity-triggered nanoparticles (NPs) with size reduction and charge switchable features to boost tumor immunotherapy based on indoleamine 2,3-dioxygenase 1 siRNA (IDO1 siRNA) and immunogenic cell death (ICD). The NPs significantly augmented tumor penetrating ability and improved cellular uptake via the detachment of 2,3-dimethylmaleic anhydride-grafted poly(ethylene glycol)-poly(L-lysine) copolymer (mPEG-PLL-DMA, PLM) from large-sized NPs with a negative charge. Subsequently, the NPs with a positive charge and small size rapidly escaped from the lysosomes and released mitoxantrone (MIT) and IDO1 siRNA. The antitumor immune response of IDO1 siRNA and MIT provided good antitumor capability by enhancing DC maturation, improving the number of CTLs, and downregulating the level of Tregs in tumor tissues. In summary, the results demonstrated that charge-switchable NPs based on the blockage of the IDO1 pathway and ICD activation induce an efficient antitumor immune response, thus showing high potential for treating primary/distant tumors and reducing metastasis. STATEMENT OF SIGNIFICANCE: Acidity-triggered nanoparticles (NPs) with size reduction and charge reversal to boost tumor immunotherapy based on indoleamine 2,3-dioxygenase 1 siRNA (IDO1 siRNA) and immunogenic cell death (ICD) were engineered. NPs augmented tumor penetrating ability and improved cellular uptake through the detachment of mPEG-PLL-DMA (PLM) from the large-sized MIT/siR-PLM/PPA NPs with negative charge to expose miniature and positively charged MIT/siR-PPA NPs. The NPs rapidly escaped from the lysosome and sequentially released mitoxantrone (MIT) and IDO1 siRNA. The antitumor synergistic effect of inhibiting the IDO1 pathway by IDO1 siRNA and inducing ICD by MIT provided good antitumor capability by enhancing DC maturation, improving the number of CTLs, and downregulating the level of Tregs in tumor tissues. Thus, the NPs showed a promising pathway against aggressive and difficult-to-treat cancers.

Tumor-specific nitric oxide generator to amplify peroxynitrite based on highly penetrable nanoparticles for metastasis inhibition and enhanced cancer therapy.

Multiple biological barriers and tumor metastasis severely impede the tumor therapy. To address these adversities, an acid-activated poly (ethylene glycol)-poly-l-lysine-2,3-dimethylmaleic anhydride/poly (ε-caprolactone)-poly(l-arginine)/ß-lapachone nanoparticles (mPEG-PLL-DMA/PCL-P(L-arg)/ß-Lap, PLM/PPA/ß-Lap NPs) were constructed with charge-reversal and size-reduction for ß-Lap delivery with a cascade reaction of reactive oxygen species (ROS) and nitric oxide (NO) production. The nanosystem exhibited highly penetrable, superior cellular uptake and desirable endo-lysosomal escape thanks to size-reduction, charge-reversal and proton sponge, respectively. The vast bulk of ROS, which rapidly generated from ß-Lap under high concentration quinone oxidoreductase 1 (NQO1), catalyzed guanidine groups to produce NO and generated highly toxic peroxynitrite (ONOO-). ONOO- would activate pro-matrix metalloproteinases (pro-MMPs) to generate MMPs, degrade the dense extracellular matrix (ECM) to augment the penetration capability, and aggravate DNA damage. NO and ONOO- influenced mitochondrial function by decreasing mitochondrial membrane potential and prevented the production of adenosine triphosphate (ATP), which inhibited the ATP-dependent tumor-derived microvesicles (TMVs) and restrained tumor metastasis. NO was defined as an epithelial mesenchymal transition (EMT) inhibitor to restrain tumor metastasis. All consequences demonstrated that PLM/PPA/ß-lap NPs exhibited efficient penetration capability, outstanding anti-metastasis activity and favorable antitumor efficacy. Those novel acid-activated NPs are intended to provide further inspiration for multifunctional NO gas therapy.

Binary regulation of the tumor microenvironment by a pH-responsive reversible shielding nanoplatform for improved tumor chemo-immunotherapy.

The limited infiltration of specific T cells in an immunosuppressive microenvironment is a major challenge for cancer immunotherapy. Reversing tumor microenvironment and inducing an antitumor immune response are crucial for cancer therapy. Here, phenylboronic acid (PBA) derivative-stabilized ultrasmall platinum nanoparticles (PBA-Pt) and dextran-coated BLZ-945 nanoparticles (DNPs) were co-assembled through a pH-responsive borate ester bond to construct a versatile reversible shielding multifunctional nanoplatform (Pt@DNPs) for the first time. Pt@DNPs dissociated into two individual components, namely PBA-Pt and DNPs, in the tumor acid microenvironment. Both in vitro and in vivo studies revealed that Pt@DNPs induced immunogenic cell death (ICD) (through multimechanisms involving PtⅡ release and a multienzyme catalytic process by PBA-Pt) and relieved immunosuppressive microenvironment (depletion of tumor-associated macrophages by BLZ-945), which led to tumor-associated antigen release, maturation of dendritic cells, and infiltration of cytotoxic T cells for efficient antitumor immune response against both primary tumor and pulmonary metastatic tumor nodules. Therefore, Pt@DNPs is a promising option for cancer chemo-immunotherapy. STATEMENT OF SIGNIFICANCE: A versatile reversible shielding multifunctional nanoplatform (Pt@DNPs) was engineered for the first time for combinational cancer chemo-immunotherapy. Multimechanisms involving induction of immunogenic cell death by PBA-Pt and sufficient TAM depletion by DNPs could efficiently relieve tumor immunosuppressive microenvironment and activate the antitumor immune response. The synergistic effect not only increased the infiltration of specific T cells in primary tumor, but it also induced a strong immune response against pulmonary metastatic nodules. Collectively, this nanoplatform may represent a promising strategy for combinational chemo-immunotherapy for cancers.

Self-amplified ROS production from fatty acid oxidation enhanced tumor immunotherapy by atorvastatin/PD-L1 siRNA lipopeptide nanoplexes.

Despite the important role of reactive oxygen species (ROS) in battling cancer, ROS production with current approaches has been severely limited by the deficiency of oxy-substrates in tumor microenvironment. Herein, an atorvastatin (Ato)-catalytic self-amplified approach was utilized for sustainable ROS production and enhancing anti-tumor efficacy of PD-L1 silencing. A C18-pArg8-ss-pHis10 lipopeptide based self-assembled nanoplexes was developed to co-encapsulate AMP-activated protein kinase (AMPK) activator of Ato and PD-L1 siRNA. Efficient delivery of payloads was achieved because of the acidic pH triggered the protonation of pHis10, disulfide-bond exposure for cleavage and subsequent cytosolic translocation. Ato was found to activate AMPK, boosting the highly restrained mitochondrial fatty acid oxidation (FAO) in cancer cells for ROS production. The ROS derived from FAO further activated AMPK, creating a positive-feedback mechanism of sustainable ROS production. The self-amplified ROS production from cellular mitochondrial FAO was maintained by the sufficient intracellular fatty acid substrates arising from the dysregulated lipid metabolism and Ato inhibited triglyceride synthesis in cancer cells. The excessive ROS level was found to successfully induce immunogenic cell death effect, boosting the anti-tumor efficacy of PD-L1 silencing. Overall, the Ato catalyzed self-amplified ROS production has been demonstrated as a promising alternative for cancer therapy.

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 (Fe2+) were co-assembled into nanosized amplifier (ADO-Fe) through π‒π stacking 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 H2O2 concentration would induce hydroxyl radical (·OH) and oxygen (O2) generation through Fenton reaction by Fe2+. 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.

A phenolic based tumor-permeated nano-framework for immunogenic cell death induction combined with PD-L1 immune checkpoint blockade.

A critical obstacle for programmed death ligand 1 (PD-L1) immune checkpoint blockade immunotherapy is the insufficient T cell infiltration and low immunogenicity of tumor cells. Improving tumor immunogenicity through immunogenic cell death (ICD) can make tumor sensitive to PD-L1 checkpoint blockade immunotherapy. Herein, a phenolic based tumor-permeated nano-framework (EGPt-NF) was fabricated by cross-linking phenylboric acid modified platinum nanoparticles (PBA-Pt, ICD inducer) and epigallocatechin-3-O-gallate (EGCG, PD-L1 inhibitor) via pH-reversible borate ester. In particular, PBA-Pt could not only induce ICD cascade but also relieve tumor hypoxia. Consequently, EGPt-NF could effectively promote dendritic cell maturation and downregulate PD-L1 expression in tumor cells. Furthermore, EGPt-NF could also relieve tumor hypoxia to facilitate cytotoxic T lymphocyte infiltration and IFN-γ secretion. The synergistic effect of EGPt-NF could effectively improve tumor immunogenicity and amplify the therapeutic outcomes of cancer immunotherapy, resulting in a strong antitumor immune response in primary tumor and metastasis inhibition. Our simple approach expands the application of platinum-based drug delivery systems for cancer immunotherapy.

Watson-Crick Base Pairing-Inspired Laser/GSH Activatable miRNA-Coordination Polymer Nanoplexes for Combined Cancer Chemo-Immuno-Photothermal Therapy.

The tumor immunosuppressive microenvironment (TIM) greatly hindered the efficacy of cancer immunotherapy. Overexpressed indoleamine 2,3-dioxygenase-1 (IDO1) in tumor tissues plays a vital role in TIM generation, and downregulation of IDO1 expression may reverse TIM. Inspired by the Watson-Crick base-pairing rule, a versatile noncationic miRNA vector (miDAC@PDA) is developed for cancer immunotherapy. Doxorubicin (DOX), adenosine triphosphate (ATP), and copper ions (Cu2+) are coassembled into coordination polymer nanoparticles (DAC) and bind miRNA via the hydrogen bond interaction (miDAC) between adenine residues (ATP) and uracil residues (miRNA). Polydopamine (PDA) is deposited onto the surface of miDAC for photothermal therapy. miDAC@PDA can efficiently accumulate into tumor tissues for cellular uptake. Under laser irradiation and high intracellular GSH levels, the PDA shell of miDAC@PDA can dissociate from miDAC for miRNA release due to local hyperthermia. Cu2+-mediated GSH consumption and intracellular ATP release can amplify the DOX-based immunogenic cell death (ICD) cascade, together with miR-448-mediated IDO1 inhibition, and these versatile nanoplexes will not only restrain primary tumor growth but also display a remarkable abscopal effect on distant tumors. Collectively, our study provides a unique strategy for intracellular gene delivery and an inspirational approach for multimechanism cancer management.

A Self-amplifying ROS-sensitive prodrug-based nanodecoy for circumventing immune resistance in chemotherapy-sensitized immunotherapy.

Circumventing immune resistance and boosting immune response is the ultimate goal of cancer immunotherapy. Herein, we reported a tumor-associated macrophage (TAM) membrane-camouflaged nanodecoy containing a self-amplifying reactive oxygen species (ROS)-sensitive prodrug nanoparticle for specifically inducing immunogenic cell death (ICD) in combination with TAM depletion. A versatile ROS-cleavable camptothecin (CPT) prodrug (DCC) was synthesized through a thioacetal linker between CPT and the ROS generator cinnamaldehyde (CA), which could self-assemble into a uniform prodrug nanoparticle to realize a positive feedback loop of "ROS-triggered CA/CPT release and CA/CPT-mediated ROS generation." This DCC was further modified with the TAM membrane (abbreviated as DCC@M2), which could not only target both primary tumors and lung metastasis nodules through VCAM-1/α4ß1 integrin interaction but also absorb CSF-1 secreted by tumor cells to disturb the interaction between TAMs and cancer cells. Our nanodecoy could effectively induce ICD cascade and deplete TAMs for priming tumor-specific effector T cell infiltration for antitumor immune response activation, which represents a versatile approach for cancer immunotherapy. STATEMENT OF SIGNIFICANCE: A tumor-associated macrophage (TAM) membrane-camouflaged nanodecoy containing a self-amplifying reactive oxygen species (ROS)-sensitive prodrug nanoparticle was fabricated for the first time. This ROS-cleavable camptothecin (CPT)/cinnamaldehyde (CA) prodrug (DCC) could self-assemble into a uniform nanoparticle to realize the positive feedback loop of "ROS-triggered CA/CPT release and CA/CPT-mediated ROS generation." After TAM membrane coating, this system (DCC@M2) could not only target both primary tumors and lung metastatic nodules but also scavenge CSF-1 secreted by tumor cells for TAM depletion for sufficient chemotherapy-sensitized immunotherapy.

Preparation and optimization of doxorubicin-loaded albumin nanoparticles using response surface methodology.

BACKGROUND: The objective of this work was to optimize the preparation of doxorubicin-loaded albumin nanoparticles (Dox-A-Nps) through desolvation procedures using response surface methodology (RSM). A central composite design (CCD) for four factors at five levels was used in this study. METHOD: Albumin nanoparticles were prepared through a desolvation method and were optimized in the aid of CCD. Albumin concentration, amount of doxorubicin, pH values, and percentage of glutaraldehyde were selected as independent variables, particle size, zeta potential, drug loading, encapsulation efficiency, and nanoparticles yield were chosen as response variables. RSM and multiple response optimizations utilizing a quadratic polynomial equation were used to obtain an optimal formulation. RESULTS: The optimal formulation for Dox-A-Nps was composed of albumin concentration of 17 mg/ml, amount of doxorubicin of 2 mg/ml, pH value is 9 and percentage of glutaraldehyde of 125% of the theoretic amount, under which the optimized conditions gave rise to the actual average value of mean particle size (151 ± 0.43 nm), zeta potential (-18.8 ± 0.21 mV), drug loading efficiency (21.4 ± 0.70%), drug entrapment efficiency (76.9 ± 0.21%) and nanoparticles yield (82.0 ± 0.34%). The storage stability experiments proved that Dox-A-Nps stable in 4°C over the period of 4 months. The in vitro experiments showed a burst release at the initial stage and followed by a prolonged release of Dox from albumin nanoparticles up to 60 h. CONCLUSIONS: This study showed that the RSM-CCD method could efficiently be applied for the modeling of nanoparticles, which laid the foundation of the further research of immuno nanoparticles.

[The characterisitics of temperature/pH sensitive block copolymer micelles in vitro].

The dialysis method was employed to prepare blank and doxorubicin (DOX) loaded micelles formed by temperature- and pH- sensitive polyhistidine-co-polyDL-lactide-co-glycolide-co-polyethyleneglycol-co-polyDL-lactide-co-glycolide-co-polyhistidine (PHis-b-PLGA-b-PEG-b-PLGA-b-PHis). The critical micelle concentrations (CMC) of the copolymers were measured with Pyrene Fluorescent Probe Technique. The temperature- and pH- sensitive properties of the blank micelles solution were investigated by optical transmittance measurement. The morphology and diameter of DOX micelles were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The entrapment rate and drug-loading rate were determined with dialysis method. The in vitro release study was further performed to examine the temperature- and pH-responsive drug release behavior from DOX-loaded micelles. The results indicated that the CMC, entrapment efficiency and drug-loaded amount of the micelles were 7.5 x 10(-3) g x L(-1), 85.2 +/- 3.1% and 10.4 +/- 4.5%, respectively. The DOX micelle was globular-shaped with a mean diameter of 91.1 +/- 15.8 nm. The transmittance of micelle solution consistently increased with the increasing temperature or decreasing pH. In comparison to the drug release profile at physiological conditions (37 degrees C, pH 7.4), the DOX-loaded micelles showed faster drug release rate at higher temperature (41 degrees C), lower pH (pH 7.0, pH 6.5, pH 5.0) or higher temperature and lower pH (41 degrees C, pH 5.0). This indicated that the micelles showed a temperature and pH-triggered drug release pattern. Base on the above results, it can be concluded that PHis-b-PLGA-b-PEG-b-PLGA-b-PHis block copolymer micelles which respond to temperature and pH stimuli are promising smart carriers for anti-tumor drugs with the advantages of temperature- and pH- triggered drug release.