Uplifting Antitumor Immunotherapy with Lymph-Node-Targeted and Ratio-Controlled Codelivery of Tumor Cell Lysate and Adjuvant.

Cancer vaccines provide a potential strategy to cure patients. Their clinical utilization and efficacy is, however, limited by incomplete coverage of tumor neoantigens and unspecific and restricted activation of dendritic cells (DCs). Tumor cell lysates (TCLs) containing a broad spectrum of neoantigens, while are considered ideal in formulating personalized vaccines, induce generally poor antigen presentation and transient antitumor immune response. Here, intelligent polymersomal nanovaccines (PNVs) that quantitatively coload, efficiently codeliver, and responsively corelease TCL and CpG adjuvant to lymph node (LN) DCs are developed to boost antigen presentation and to induce specific and robust antitumor immunity. PNVs carrying CpG and ovalbumin (OVA) markedly enhance the maturation, antigen presentation, and downstream T cell activation ability of bone-marrow-derived dendritic cells and induce strong systemic immune response after tail base injection. Remarkably, PNVs carrying CpG and TCL cure 85% of B16-F10 melanoma-bearing mice and generate long-lasting anticancer immune memory at a low dose, protecting all cured mice from tumor rechallenge. These LN-directed PNVs being highly versatile and straightforward opens a new door for personalized cancer vaccines.

Roadmap on multifunctional materials for drug delivery.

This Roadmap on drug delivery aims to cover some of the most recent advances in the field of materials for drug delivery systems (DDSs) and emphasizes the role that multifunctional materials play in advancing the performance of modern DDSs in the context of the most current challenges presented. The Roadmap is comprised of multiple sections, each of which introduces the status of the field, the current and future challenges faced, and a perspective of the required advances necessary for biomaterial science to tackle these challenges. It is our hope that this collective vision will contribute to the initiation of conversation and collaboration across all areas of multifunctional materials for DDSs. We stress that this article is not meant to be a fully comprehensive review but rather an up-to-date snapshot of different areas of research, with a minimal number of references that focus upon the very latest research developments.

Bioresponsive Chimaeric Polymersomes Mediate Sustained and Liver-Specific siRNA Transfection In Vivo.

The silencing of disease-causing genes with small interfering RNA (siRNA) offers a particularly effective therapeutic strategy for different disorders; however, its clinical efficacy relies on the development of nontoxic and tissue-specific delivery vehicles. Herein, we report that bioresponsive chimaeric polymersomes (BCP) with short poly(ethylenimine) as inner shell mediate highly efficacious, sustained, and liver-specific siRNA transfection in vivo. BCP exhibited remarkable encapsulation efficiencies of siRNA (95-100%) at siRNA-feeding contents of 15-25 wt %, to afford stable, small-sized (55-64 nm), and neutral-charged BCP-siRNA. siApoB-Loaded BCP (BCP-siApoB) outperformed lipofectamine counterparts and silenced 93% of ApoB mRNA in HepG2 cells at 50 nM siApoB without inducing cytotoxicity. Intriguingly, the in vivo studies using wild-type C57BL/6 mice revealed that BCP-siApoB preferentially accumulated in the liver, and a single dose of 4.5 mg/kg achieved over 90% downregulation of ApoB mRNA for at least 10 days. The systemic administration of BCP-siApoB at 4.5 mg/kg every 2 weeks or 1.5 mg/kg weekly in diet-induced obese mice could also achieve up to 80% silencing of ApoB mRNA. The liver specificity and silencing efficacy of BCP-siApoB could further be improved by decorating it with the trivalent N-acetylgalactosamine (TriGalNAc) ligand. These bioresponsive and liver-specific chimaeric polymersomes provide an enabling technology for siRNA therapy of various liver-related diseases.

Antibody-Mediated Nanodrug of Proteasome Inhibitor Carfilzomib Boosts the Treatment of Multiple Myeloma.

Multiple myeloma (MM) is the second most common hematological malignancy. For relapsed and refractory MM, a proteasome inhibitor, carfilzomib (CFZ), has become one of the few clinical options. CFZ suffers, nevertheless, metabolic instability and poor bioavailability and may induce severe cardiovascular and renal adverse events. Here, we report that daratumumab (Dar)-decorated polypeptide micelles (Dar-PMs) mediate the targeted delivery of CFZ to CD38-positive MM, effectively boosting its anti-MM efficacy. CFZ-loaded Dar-PMs (Dar-PMs-CFZ) exhibited an average diameter of ca. 80 nm and Dar density-dependent cell endocytosis and anti-MM activity, in which over 6-fold greater inhibitory effect to LP-1 and MM.1S MM cells than nontargeted PMs-CFZ control was achieved at a Dar density of 3.2 (Dar3.2-PMs-CFZ). Interestingly, Dar3.2-PMs-CFZ markedly enhanced the growth inhibition of orthotopic LP-1 MM in mice and significantly extended the median survival time compared with PMs-CFZ and free CFZ (95 days vs 60 and 54 days, respectively). In line with its high MM targetability and anti-MM efficacy, Dar3.2-PMs-CFZ revealed little toxic effects and effectively prevented osteolytic lesions. The antibody-targeted nanodelivery of a proteasome inhibitor appears to be an appealing strategy to treat multiple myeloma.

Integrin-targeting disulfide-crosslinked micellar docetaxel eradicates lung and prostate cancer patient-derived xenografts.

Actively targeted nanomedicines though conceptually attractive for tumor therapy are extremely hard to realize due to problems of premature drug leakage, excessive liver accretion, inadequate tumor uptake, and/or retarded drug release inside tumor cells. Here, we systemically studied the influence of disulfide crosslinking on the in vitro and in vivo performance of integrin-targeting micellar docetaxel (t-MDTX). Of note, t-M5DTX with a high disulfide content was clearly advantageous in terms of stability, intracellular drug release, anti-tumor activity toward αVß3-overexpressing A549 cells, blood circulation and therapeutic efficacy in orthotopic A549-luc lung tumor-bearing mice. t-MDTX induced extraordinary tumor targetability with tumor-to-normal tissue ratios of 1.7-8.3. Further studies indicated that t-M5DTX could effectively eradicate αVß3-overexpressing lung and prostate cancer patient-derived xenografts (PDX), in which ca. 80% mice became tumor-free. This integrin-targeting disulfide-crosslinked micellar docetaxel emerges as a promising actively targeted nanoformulation for tumor therapy. STATEMENT OF SIGNIFICANCE: Nanomedicines have a great potential in treating advanced tumor patients; however, their tumor-targeting ability and therapeutic efficacy remain unsatisfactory. In addition to PEGylation and ligand selection, particle size, stability and drug release behavior are also critical to their performance in vivo. In this paper, we find that small and cRGD-guided disulfide-crosslinked micellar docetaxel (t-MDTX) induces superior tumor uptake and retention but without increasing liver burden, leading to extraordinary selectivity and inhibition of αvß3 overexpressing lung tumors. t-MDTX is further shown to effectively treat αvß3-positive patient-derived tumor models, lending it a high potential for clinical translation.

Targeted nanodelivery of siRNA against KRAS G12D inhibits pancreatic cancer.

Pancreatic cancer (PC) stands as a most deadly malignancy due to few effective treatments in the clinics. KRAS G12D mutation is a major driver for most PC cases, and silencing of KRAS G12D is considered as a potential therapeutic strategy for PC, which is nevertheless crippled by lacking a pragmatic delivery system for siRNA against KRAS G12D (siKRAS). Here, we report that cRGD peptide-modified bioresponsive chimaeric polymersomes (cRGD-BCP) mediate highly efficient siKRAS delivery to PANC-1 tumor, potently silencing KRAS G12D mRNA in tumor cells and effectively suppressing PC tumor growth in mice. cRGD-BCP exhibited remarkable encapsulation of siKRAS (loading content > 14 wt.%, loading efficiency > 90%) to form stable and uniform (ca. 68 nm) nanovesicles (cRGD-BCP-siKRAS). Of note, cRGD density greatly impacted the cellular uptake and silencing efficiency of cRGD-BCP-siKRAS in PANC-1 cells, in which an optimal cRGD density of 15.7 mol.% achieved 3.7- and 3.6-fold enhancement of internalization and gene silencing, respectively, compared with non-targeted BCP-siKRAS. cRGD-BCP-siKRAS was practically intact after 3-week storage at 4°C. Intriguingly, cRGD-BCP-siKRAS markedly enhanced the uptake of siKRAS in PANC-1 tumor, and at a siKRAS dose of 3 mg/kg knocked down 90% KRAS G12D gene, resulting in potent tumor inhibition and extraordinary survival benefits (median survival time: 101 days versus 38 (PBS group) and 59 days (BCP-siKRAS)) with 40% mice achieved complete regression. It appears that cRGD-mediated nanodelivery of siKRAS provides a potential cure for pancreatic cancer. STATEMENT OF SIGNIFICANCE: Small interfering RNA (siRNA) emerges as a specific and powerful biopharmaceuticals against cancers; however, inefficient in vivo delivery impedes its clinical translation. In spite of the fact that KRAS G12D mutation has been identified as a major driver for most pancreatic cancer, its notorious non-druggability renders little success on development of molecular targeted drugs. Pancreatic cancer is deemed as current king-of-cancer. Here, we show that cyclic RGD peptide installed bioresponsive polymersomes are able to efficiently deliver siRNA against KRAS G12D to pancreatic tumor, resulting in 90% gene knock-down and effective tumor inhibition. Strikingly, two out of five mice have been cured. This targeted nanodelivery of siRNA provides a high-efficacy treatment strategy for pancreatic cancer.

Exogenous Antigen Upregulation Empowers Antibody Targeted Nanochemotherapy of Leukemia.

Acute myeloid leukemia (AML) is afflicted by a high-mortality rate and few treatment options. The lack of specific surface antigens severely hampers the development of targeted therapeutics and cell therapy. Here, it is shown that exogenous all-trans retinoic acid (ATRA) mediates selective and transient CD38 upregulation on leukemia cells by up to 20-fold, which enables high-efficiency targeted nanochemotherapy of leukemia with daratumumab antibody-directed polymersomal vincristine sulfate (DPV). Strikingly, treatment of two CD38-low expressing AML orthotopic models with ATRA and DPV portfolio strategies effectively eliminates circulating leukemia cells and leukemia invasion into bone marrow and organs, leading to exceptional survival benefits with 20-40% of mice becoming leukemia-free. The combination of exogenous CD38 upregulation and antibody-directed nanotherapeutics provides a unique and powerful targeted therapy for leukemia.

CD38-selective immuno-nano-DM1 conjugates for depleting multiple myeloma.

Multiple myeloma (MM) is a neoplasm of aberrant plasma cells and ranks second among hematologic malignancies. Despite a substantial improvement in clinical outcomes with advances in therapeutic modalities over the past two decades, MM remains incurable, necessitating the development of new and potent therapies. Herein, we engineered a daratumumab-polymersome-DM1 conjugate (DPDC) based highly potent and CD38-selective immuno-nano-DM1 toxin for depleting MM cells in vivo. DPDC with controllable daratumumab density and disulfide-linked DM1 is of small size (51-56 nm), with high stability and reduction-triggered DM1 release. D6.2PDC potently inhibited the proliferation of CD38-overexpressed LP-1 and MM.1S MM cells with IC50 values of 2.7 and 1.2 ng DM1 equiv. per mL, about 4-fold stronger than non-targeted PDC. Moreover, D6.2PDC effectively and safely depleted LP-1-Luc MM cells in an orthotopic mouse model at a low DM1 dosage of 0.2 mg kg-1, thus alleviating osteolytic bone lesion and extending the median survival by 2.8-3.5-fold compared to all controls. This CD38-selective DPDC provides a safe and potent treatment strategy for MM.

RGD-directed 24 nm micellar docetaxel enables elevated tumor-liver ratio, deep tumor penetration and potent suppression of solid tumors.

Nanomedicines while showing a great potential in improving the performance of chemotherapeutics like docetaxel (DTX) are distressed by a high liver deposition and poor tumor penetration, which might not only cause liver toxicity but also moderate therapeutic effect. Herein, we report that cRGD-directed 24 nm disulfide-crosslinked micellar docetaxel (cRGD-MDTX) presents low liver accumulation, high tumor uptake, and deep tumor penetration, leading to the potent suppression of different solid tumors. cRGD-MDTX was optimized with a cRGD density of 4% and DTX loading of 10 wt%. Interestingly, cRGD-MDTX enabled an extraordinary tumor-liver ratio of 2.8/1 with a DTX uptake of 8.3 %ID/g in αvß3 over-expressing PC3 prostate tumor. The therapeutic studies demonstrated striking antitumor effects of cRGD-MDTX toward PC3 prostate tumor, prostate cancer patient-derived xenografts (PDX), orthotopic A549-Luc lung cancer and orthotopic SKOV3-Luc ovarian tumor models, in which tumor growth was effectually inhibited and 6-8 times better improvement of median survival time over free DTX was observed. This small disulfide-crosslinked micellar drug capable of relegating liver deposition opens a new avenue to nanomedicines for targeted therapy.

Reactive oxygen species-powered cancer immunotherapy: Current status and challenges.

Reactive oxygen species (ROS) are crucial signaling molecules that can arouse immune system. In recent decades, ROS has emerged as a unique therapeutic strategy for malignant tumors as (i) it can not only directly reduce tumor burden but also trigger immune responses by inducing immunogenic cell death (ICD); and (ii) it can be facilely generated and modulated by radiotherapy, photodynamic therapy, sonodynamic therapy and chemodynamic therapy. The anti-tumor immune responses are, however, mostly downplayed by the immunosuppressive signals and dysfunction of effector immune cells within the tumor microenvironment (TME). The past years have seen fierce developments of various strategies to power ROS-based cancer immunotherapy by e.g. combining with immune checkpoints inhibitors, tumor vaccines, and/or immunoadjuvants, which have shown to potently inhibit primary tumors, metastatic tumors, and tumor relapse with limited immune-related adverse events (irAEs). In this review, we introduce the concept of ROS-powered cancer immunotherapy, highlight the innovative strategies to boost ROS-based cancer immunotherapy, and discuss the challenges in terms of clinical translation and future perspectives.

Nanoparticle-Mediated STING Activation for Cancer Immunotherapy.

As the first line of host defense against pathogenic infections, innate immunity plays a key role in antitumor immunotherapy. The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) (cGAS-STING) pathway has attracted much attention because of the secretion of various proinflammatory cytokines and chemokines. Many STING agonists have been identified and applied into preclinical or clinical trials for cancer immunotherapy. However, the fast excretion, low bioavailability, nonspecificity, and adverse effects of the small molecule STING agonists limit their therapeutic efficacy and in vivo application. Nanodelivery systems with appropriate size, charge, and surface modification are capable of addressing these dilemmas. In this review, the mechanism of the cGAS-STING pathway is discussed and the STING agonists, focusing on nanoparticle-mediated STING therapy and combined therapy for cancers, are summarized. Finally, the future direction and challenges of nano-STING therapy are expounded, emphasizing the pivotal scientific problems and technical bottlenecks and hoping to provide general guidance for its clinical application.

Mannose-mediated nanodelivery of methotrexate to macrophages augments rheumatoid arthritis therapy.

Rheumatoid arthritis (RA) is a chronic autoimmune disease that gravely jeopardizes the quality of life of numerous people. Methotrexate (MTX) is a disease-modifying anti-rheumatic drug commonly used in clinics; however, it suffers from slow onset, moderate efficacy, and adverse reactions such as renal dysfunction, myelosuppression, and bone erosion after long-term treatment. Here, we explored macrophage targeted delivery of MTX using mannose-installed chimaeric polymersomes (Man-PMTX) as an advanced treatment for RA. Man-PMTX exhibited high (∼18 wt%) and robust loading of MTX, uniform size of 51-55 nm, minimal hemolytic activity, and glutathione-actuated drug release property. Man-PMTX showed better uptake by activated macrophages than PMTX, and more repolarization of bone marrow-derived macrophages (BMDMs) to anti-inflammatory M2 type macrophages and less secretion of TNF-α and IL-1ß compared with free MTX and PMTX. In vivo studies revealed that Man-PMTX showed significantly higher accumulation in inflammatory joints than in healthy joints and effectively treated RA by relieving inflammation, repolarizing macrophages from M1 type to M2 type, and mitigating proinflammatory cytokines. Accordingly, Man-PMTX effectively protected the synovium and bone from damage. Mannose-mediated nanodelivery of methotrexate to macrophages appears to be an attractive strategy to augment rheumatoid arthritis therapy.

Co-delivery of gemcitabine and paclitaxel plus NanoCpG empowers chemoimmunotherapy of postoperative "cold" triple-negative breast cancer.

Triple-negative breast cancer (TNBC) due to lack of clear target and notorious "cold" tumor microenvironment (TME) is one of the most intractable and lethal malignancies. Tuning "cold" TME into "hot" becomes an emerging therapeutic strategy to TNBC. Herewith, we report that integrin-targeting micellar gemcitabine and paclitaxel (ATN-mG/P, ATN sequence: Ac-PhScNK-NH2) cooperating with polymersomal CpG (NanoCpG) effectively "heated up" and treated TNBC. ATN-mG/P exhibited greatly boosted apoptotic activity in 4T1 cells, induced potent immunogenic cell death (ICD), and efficiently stimulated maturation of bone marrow-derived dendritic cells (BMDCs). Remarkably, in a postoperative TNBC model, ATN-mG/P combining with NanoCpG promoted strong anti-cancer immune responses, showing a greatly augmented proportion of mature DCs and CD8+ T cells while reduced immune-suppressive myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Treg), which led to complete inhibition of lung metastasis and 60% mice tumor-free. The co-delivery of gemcitabine and paclitaxel at desired ratio in combination with NanoCpG provides a unique platform for potent chemoimmunotherapy of "cold" tumors like TNBC.

Codelivery of BCL2 and MCL1 Inhibitors Enabled by Phenylboronic Acid-Functionalized Polypeptide Nanovehicles for Synergetic and Potent Therapy of Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is the most refractory hematologic malignancy characterized by acute onset, rapid progression, and high recurrence rate. Here, codelivery of BCL2 (ABT199) and MCL1 (TW37) inhibitors using phenylboronic acid-functionalized polypeptide nanovehicles to achieve synergetic and potent treatment of AML is adopted. Leveraging the dynamic boronic ester bonds, BN coordination, and π-π stacking, the nanovehicles reveal remarkably efficient and robust drug coencapsulation. ABT199 can induce a series of pro-apoptotic reactions by promoting the dissociation of the pro-apoptotic protein Bim from BCL2, while the released Bim is often captured by MCL1 protein overexpressed in AML. TW37 has a strong inhibitory ability to MCL1, thereby can restrain the depletion of Bim protein. Dual inhibitor-loaded nanoparticles (NPAT) reveal excellent stability, acid/enzyme/H2 O2 -triggered drug release, and significant cytotoxicity toward MOLM-13-Luc and MV-411 AML cells with low half maximal inhibitory concentrations of 1.15 and 7.45 ng mL-1 , respectively. In mice bearing MOLM-13-Luc or MV-411 AML cancer, NPAT reveal significant inhibition of tumor cell infiltration in bone marrow and main organs, potent suppression of tumor growth, and remarkably elevated mouse survival. With facile construction, varying drug combination, superior safety, synergetic efficacy, the phenylboronic acid-functionalized smart nanodrugs hold remarkable potential for AML treatment.

Lysosomal-mediated drug release and activation for cancer therapy and immunotherapy.

The development of carrier systems that are able to transport and release therapeutics to target cells is an emergent strategy to treat cancer; however, they following endocytosis are usually trapped in the endo/lysosomal compartments. The efficacy of drug conjugates and nanotherapeutics relies critically on their intracellular drug release ability, for which advanced systems responding to the unique lysosomal environment such as acidic pH and abundant enzymes (e.g. cathepsin B, sulfatase and ß-glucuronidase) or equipped with photochemical internalization property have been energetically pursued. In this review, we highlight the recent designs of smart systems that promote efficient lysosomal release and/or escape of anticancer agents including chemotherapeutics (e.g. doxorubicin, platinum, chloroquine and hydrochloroquine) and biotherapeutics (e.g. proteins, siRNA, miRNA, mRNA and pDNA) to cancer cells or immunotherapeutic agents (e.g. antigens, mRNA and immunoadjuvants) to antigen-presenting cells (APCs), thereby boosting cancer therapy and immunotherapy. Lysosomal-mediated drug release presents an appealing approach to develop innovative cancer therapeutics and immunotherapeutics.

Transferrin-guided intelligent nanovesicles augment the targetability and potency of clinical PLK1 inhibitor to acute myeloid leukemia.

Acute myeloid leukemia (AML) remains a most lethal hematological malignancy, partly because of its slow development of targeted therapies compared with other cancers. PLK1 inhibitor, volasertib (Vol), is among the few molecular targeted drugs granted breakthrough therapy status for AML; however, its fast clearance and dose-limiting toxicity greatly restrain its clinical benefits. Here, we report that transferrin-guided polymersomes (TPs) markedly augment the targetability, potency and safety of Vol to AML. Vol-loaded TPs (TPVol) with 4% transferrin exhibited best cellular uptake, effective down-regulation of p-PLK1, p-PTEN and p-AKT and superior apoptotic activity to free Vol in MV-4-11 leukemic cells. Intravenous injection of TPVol gave 6-fold higher AUC than free Vol and notable accumulation in AML-residing bone marrow. The efficacy studies in orthotopic MV-4-11 leukemic model demonstrated that TPVol significantly reduced leukemic cell proportions in periphery blood, bone marrow, liver and spleen, effectively enhanced mouse survival rate, and impeded bone loss. This transferrin-guided nano-delivery of molecular targeted drugs appears to be an interesting strategy towards the development of novel treatments for AML.

Across-cancer specific immune responses induced by nanovaccines or microvaccines to prevent different cancers and cancer metastasis.

Metastatic cancers and recurrent cancers are diverse, different from primary cancers, and organ-dependent. However, how strong are across-cancer immune responses among different types of cancers remain unclear. Herein, vaccines-encapsulated-whole-components-of-tumor-tissue (VEWCOTT) were applied to demonstrate the across-cancer immune responses, thanks to inducing pan-clones T-cell immune responses. Either lung-cancer-tissue- or melanoma-tissue-based VEWCOTT simultaneously prevented melanoma, lung cancer, hepatoma, and metastatic cancer, which showed that strong across-cancer immune responses were induced. Both nanovaccines and microvaccines showed potent across-cancer prevention efficacy. VEWCOTT induced tumor-specific T cells in peripheral immune organs and major organs, and adjusted the immune-microenvironment of cancer-colonized organs. In addition, the allograft of T cells from VEWCOTT immunized mice to allogeneic naive mice efficiently prevent various cancers. Many neoantigens are shared by melanoma cells and lung cancer cells. Across-cancer immune responses exist among different types of cancers, and thus VEWCOTT has the advantage of simultaneously preventing cancer metastasis and cancers in different organs.

External stimuli-responsive gasotransmitter prodrugs: Chemistry and spatiotemporal release.

Gasotransmitters like nitric oxide, carbon monoxide, and hydrogen sulfide with unique pleiotropic pharmacological effects in mammals are an emerging therapeutic modality for different human diseases including cancer, infection, ischemia-reperfusion injuries, and inflammation; however, their clinical translation is hampered by the lack of a reliable delivery form, which delivers such gasotransmitters to the action site with precisely controlled dosage. The external stimuli-responsive prodrug strategy has shown tremendous potential in developing gasotransmitter prodrugs, which affords precise temporospatial control and better dose control compared with endogenous stimuli-sensitive prodrugs. The promising external stimuli employed for gasotransmitter activation range from photo, ultrasound, and bioorthogonal click chemistry to exogenous enzymes. Herein, we highlight the recent development of external stimuli-mediated decaging chemistry for the temporospatial delivery of gasotransmitters including nitric oxide, carbon monoxide, hydrogen sulfide and sulfur dioxide, and discuss the pros and cons of different designs.