Antibody-mertansine (DM1) conjugates (AMCs) are among the very few active targeting therapeutics that are approved or clinically investigated for treating various cancers including metastatic breast cancer. However, none of the AMCs are effective for the treatment of triple-negative breast cancers (TNBCs). Here, we show that cRGD-decorated, redox-activatable micellar mertansine prodrug (cRGD-MMP) can effectively target and deliver DM1 to αvβ3 integrin overexpressing MDA-MB-231 TNBC xenografts in nude mice, resulting in potent tumor growth inhibition. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays showed that cRGD-MMP had obvious targetability to MDA-MB-231 cells with a low half-maximal inhibitory concentration (IC50) of 0.18 μM, which was close to that of free DM1 and 2.2-fold lower than that of micellar mertansine prodrug (MMP; nontargeting control). The confocal microscopy studies demonstrated that cRGD-MMP mediated a clearly more efficient cellular uptake and intracellular release of doxorubicin (used as a fluorescent anticancer drug model) in MDA-MB-231 cells. Notably, cRGD-MMP loaded with 1,1'-dioctadecyltetramethyl indotricarbocyanine iodide (DiR; a hydrophobic near-infrared dye) was shown to quickly accumulate in the MDA-MB-231 tumor with strong DiR fluorescence from 2 to 24 h post injection. MMP loaded with DiR could also accumulate in the tumor, although significantly less than cRGD-MMP. The biodistribution studies revealed a high DM1 accumulation of 8.1%ID/g in the tumor for cRGD-MMP at 12 h post injection. The therapeutic results demonstrated that cRGD-MMP effectively suppressed MDA-MB-231 tumor growth at 1.6 mg DM1 equiv./kg without causing noticeable side effects, as shown by little body weight loss and histological analysis. This MMP has appeared as a promising platform for potent treatment of TNBCs.

Lung cancer, with its high mortality and increasing morbidity, has become one of the most lethal malignancies worldwide. Here, we developed cyclic RGD peptide-directed and disulfide-crosslinked polymersomal doxorubicin (cRGD-PS-Dox) as a targeted chemotherapy for human non-small cell lung cancer (NSCLC). Notably, cRGD-PS-Dox exhibited a high Dox loading (15.2 wt.%), small hydrodynamic diameter (96 nm), superb stability, prominent targetability to αvβ3 integrin overexpressing A549 human lung cancer cells, and rapid release of the drug into nuclei, leading to a significantly improved antitumor activity compared with the control groups, i.e., PS-Dox and Lipo-Dox (a liposome injection employed in clinical settings). The pharmacokinetic and biodistribution results for cRGD-PS-Dox revealed similar elimination half-lives but two-fold enhanced tumor accumulation compared with PS-Dox and Lipo-Dox. Intriguingly, cRGD-PS-Dox effectively suppressed the growth of A549 lung tumors in both subcutaneous and orthotopic models with minimal adverse effects at a Dox dose of 12 mg/kg, leading to significant survival benefits compared with PS-Dox and Lipo-Dox. This αvβ3 integrin-targeting multifunctional polymersomal doxorubicin is highly promising for targeted chemotherapy of human NSCLC.

Glioblastoma with intracranial infiltrative growth remains an incurable disease mainly owing to existence of blood brain barrier (BBB) and off-target drug toxicity. RNA interference (RNAi) with a high specificity and low toxicity emerges as a new treatment modality for glioblastoma. The clinical application of RNAi technology is, however, hampered by the absence of safe and brain-targeting transfection agents. Here, we report on angiopep-2 peptide-decorated chimaeric polymersomes (ANG-CP) as a nontoxic and brain-targeting non-viral vector to boost the RNAi therapy for human glioblastoma in vivo. ANG-CP shows excellent packaging and protection of anti-PLK1 siRNA (siPLK1) in its lumen while quickly releasing payloads in a cytoplasmic reductive environment. Notably, in vitro experiments demonstrate that ANG-CP can effectively permeate the bEnd.3 monolayer, transport siRNA into the cytosol of U-87 MG glioblastoma cells via the LRP-1-mediated pathway, and significantly silence PLK1 mRNA and corresponding oncoprotein in U-87 MG cells. ANG-CP greatly prolongs the siPLK1 circulation time and enhances its accumulation in glioblastoma. RNAi with siPLK1 induces a strong anti-glioblastoma effect and significantly improves the survival time of glioblastoma carrying mice.

Brain metastases are a most disturbing situation for breast cancer patients as there is basically no adequate treatment available. Any potential drug formulation has to be able to cross the blood-brain barrier (BBB) and specific to metastatic brain tumors without causing unacceptable adverse effects. Here, we developed transferrin-functionalized chimeric polymersomes carrying siRNA against polo-like kinase 1 (Tf@TBP-CPs-siPLK1) for treating brain metastatic MDA-MB 231 triple negative breast cancer (TNBC) xenografts in mice. To facilitate the loading of siPLK1, chimaeric polymersomes (CPs) were designed with spermine in the watery core and transferrin-binding peptide (TBP) at the surface, enabling attachment of transferrin after the siRNA loading step and thereby circumventing interference of transferrin with siRNA loading. Tf@TBP-CPs-siPLK1 encapsulating 3.8 wt% siRNA had a mean size of about 50 nm and a neutral zeta potential in phosphate buffer (PB). By virtue of the presence of transferrin, Tf@TBP-CPs demonstrated greatly (ca. 5-fold) enhanced internalization in MDA-MB 231 cells and transcytosis in the endothelial (bEnd.3) monolayer model in vitro as well as markedly improved accumulation in the orthotopically xenografted MDA-MB 231 tumor in the brain in vivo compared with control CPs lacking transferrin, supporting that transferrin mediates efficient BBB penetration and high specificity towards MDA-MB 231 cells. As a result, Tf@TBP-CPs-siPLK1 effectively inhibited tumor progression and prolonged the lifespan of the mice significantly. Selective transferrin coating appears to be a particularly facile strategy to fabricate BBB-permeable and targeted vesicles for potent RNAi therapy of brain metastatic breast cancer.

Oncolytic peptide LTX-315 while showing clinical promise in treating solid tumors is limited to intratumoral administration, which is not applicable for inaccessible or metastatic tumors. The cationic and amphipathic nature of oncolytic peptides engenders formidable challenges to developing systems for their systemic delivery. Here, we describe cRGD-functionalized chimaeric polymersomes (cRGD-CPs) as a robust systemic delivery vehicle for LTX-315, which in combination with CpG adjuvant and anti-PD-1 boost immunotherapy of malignant B16F10 melanoma in mice. cRGD-CPs containing 14.9 wt% LTX-315 (cRGD-CPs-L) exhibited a size of 53 nm, excellent serum stability, and strong and selective killing of B16F10 cells (versus L929 fibroblasts) in vitro, which provoked similar immunogenic effects to free LTX-315 as revealed by release of danger-associated molecular pattern molecules. The systemic administration of cRGD-CPs-L gave a notable tumor accumulation of 4.8% ID/g and significant retardation of tumor growth. More interestingly, the treatment of B16F10 tumor-bearing mice was further boosted by co-administration of polymersomal CpG and anti-PD-1 antibody, in which two out of seven mice were cured as a result of strong immune response and long-term immune memory protection. The immunotherapeutic effect was evidenced by secretion of IL-6, IFN-γ and TNF-α, tumor infiltration of CD8+ CTLs and Th, and induction of TEM and TCM in spleen. This study opens a new avenue to oncolytic peptides, which enables durable immunotherapy of tumors via systemic administration.

Triple negative breast cancer (TNBC) with easy metastasis, "cold" tumor immune microenvironment, and lack of targeted therapy remains poorly prognosed. Chemo-immunotherapy deemed as a potential treatment for TNBC is however confronted by low TNBC selectivity, pronounced systemic toxicity, and limited immunogenic cell death (ICD) induction. Here, employing clinically validated ATN peptide as a ligand and reduction-sensitive biodegradable micelles as a vehicle we constructed α5β1 integrin-targeted micellar paclitaxel (ATN-MPTX) to elicit strong and selective ICD and chemo-immunotherapy of TNBC. ATN-MPTX exhibited evident targetability and prominent uptake in α5β1 integrin-positive 4 T1 cells and induced significantly stronger ICD than free PTX and non-targeted MPTX. The therapeutic studies in 4 T1 TNBC model demonstrated that ATN-MPTX caused superior tumor accumulation and treatment efficacy to all controls. Of note, ATN-MPTX plus nano-STING agonist further augmented the immunotherapeutic effects by increasing secretion of proinflammatory cytokines and CD4+ and CD8+ T cells in the tumor and spleen while reducing Treg, leading to significantly improved inhibition of 4 T1 primary tumor and more interestingly mitigated lung metastases. This strong and selective ICD induction of ATN-MPTX renders it an interesting tool to enhance chemo-immunotherapy of TNBC.

Antibody-drug conjugates (ADCs) are among the most significant advances in clinical cancer treatments, however, they are haunted with fundamental issues like low drug/antibody ratio (DAR), need of large amount of antibody, and complex chemistry. Targeted nanomedicines while offering a promising alternative to ADCs are afflicted with drug leakage and inferior cancer-specificity. Herein, we developed an intelligent cell-selective nanotoxin based on anti-CD44 antibody-polymersome-DM1 conjugates (aCD44-AP-DM1) for potent treatment of solid tumors. DM1 was simultaneously coupled to vesicular membrane via disulfide bonds during self-assembly and anti-CD44 antibody was facilely clicked onto polymersome surface, tailor-making an optimal aCD44-AP-DM1 with a controlled antibody density of 5.0, extraordinary DAR of 275, zero drug leakage and rapid reduction-responsive DM1 release. aCD44-AP-DM1 displayed a high specificity and exceptional cytotoxicity toward MDA-MB-231 triple negative breast cancer, SMMC-7721 hepatocellular carcinoma and A549 non-small cell lung cancer cells with half-maximal inhibitory concentrations (IC50) of 21.4, 3.7 and 64.6 ng/mL, respectively, 3.6-47.2-fold exceeding non-targeted P-DM1. Intriguingly, the systemic administration of aCD44-AP-DM1 significantly suppressed subcutaneous MDA-MB-231 tumor xenografts in nude mice while intratumoral injection achieved complete tumor eradication in four out of five mice, without causing toxicity. This intelligent cell-selective nanotoxin has emerged as a better platform over ADCs for targeted cancer therapy.

Transferrin receptor (TfR) is a promising target validated in the clinical trials for managing various malignancies. Transferrin (Tf) and single chain antibody fragment can target TfR and are typically conjugated to nanomedicines via post-modification, which poses significant production challenges. Here, we report that the polymersomes functionalized with a Tf-binding peptide CGGGHKYLRW (TBP-Ps) can selectively and stably bind Tf and subsequently mediate targeted doxorubicin (Dox) delivery to TfR over-expressing HCT-116 colorectal cancer cells in vitro and in vivo. The Tf surface density of the polymersomes could be controlled by the surface content of TBP. Interestingly, modifying Dox-loaded TBP-Ps with Tf led to greatly increased cellular uptake and inhibitory effect of HCT-116 cells. Tf-bound TBP-Ps demonstrated rapid accumulation in the tumor xenografts in nude mice following i.v. injection. More importantly, Dox-loaded Ps with Tf binding significantly enhanced the antitumor efficacy in mice bearing HCT-116 tumors compared to polymersomes without Tf binding. Surface functionalization of the nanoparticles with Tf-binding peptide provides an appealing strategy in formulating Tf-targeted nanomedicines.

Cyclic dinucleotides (CDNs) as stimulator of interferon genes (STING) agonists capable of inducing strong antitumor innate immune response are highly promising for tumor immunotherapy. The efficacy of these CDNs is, however, reduced greatly by their fast clearance, poor cell uptake and inefficient cytosolic transportation. Here, we report that reduction-responsive biodegradable chimaeric polymersomes (CPs) markedly enhance tumor retention and cytosolic delivery of a synthetic CDN, ADU-S100, and bolster STING pathway activation in the tumor microenvironment and tumor draining lymph nodes, giving significantly better tumor repression and survival of B16F10 melanoma-bearing mice compared with free CDN control. The superiority of CPs-mediated CDN delivery is further verified in combination therapy with low-dose fractionated radiation, which brings about clearly stronger and longer-term immunotherapeutic effects and protection against tumor re-challenge. The development of nano-STING agonists that are able to overcome the delivery barriers of CDNs represents an effective strategy to potentiate cancer immunotherapy.

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.

Acute myeloid leukemia (AML) is a severe blood malignancy associated with a high relapse rate. The current clinical chemotherapy is typically perplexed with serious side effects. Here, A6 peptide-tagged, small and reduction-sensitive polymersomal vincristine sulfate (A6-cPS-VCR) is reported as a novel, smart and specific treatment for CD44 positive AML. A6-cPS-VCR stably loaded with 3.3 wt% VCR displays a size of ≈ 31 nm and pronounced selectivity toward CD44-overexpressed MV4-11 leukemia cells. Intriguingly, A6-cPS-VCR effectively represses the outgrowth of orthotopic MV4-11 AML in vivo, as revealed by significant reduction of leukemia burdens in the circulation, bone marrow, liver and spleen, and significantly extends the median survival time of MV4-11 AML-bearing mice. In addition to active targetability and therapeutic benefits, A6-cPS-VCR has the advantage of easy fabrication, rendering it potentially interesting for clinical translation.

The chemotherapy of hematological cancers is challenged by its poor selectivity that leads to low therapeutic efficacy and pronounced adverse effects. Here, we report that doxorubicin encapsulated in lipoic acid-crosslinked hyaluronic acid nanoparticles (LACHA-DOX) mediate highly efficacious and targeted inhibition of human hematological cancers including LP-1 human multiple myeloma (MM) and AML-2 human acute myeloid leukemia xenografted in nude mice. LACHA-DOX had a size of ca. 183 nm and a DOX loading content of ca. 12.0 wt.%. MTT and flow cytometry assays showed that LACHA-DOX possessed a high targetability and antitumor activity toward CD44 receptor overexpressing LP-1 human MM cells and AML-2 human acute myeloid leukemia cells. The in vivo and ex vivo images revealed that LACHA-DOX achieved a significantly enhanced accumulation in LP-1 and AML-2 tumor xenografts. Notably, LACHA-DOX effectively suppressed LP-1 as well as AML-2 tumor growth and drastically increased mice survival rate as compared to control groups receiving free DOX or PBS. Histological analyses exhibited that LACHA-DOX caused little damage to the major organs like liver and heart. This study provides a proof-of-concept that lipoic acid-crosslinked hyaluronic acid nanoparticulate drugs may offer a more safe and effective treatment modality for CD44 positive hematological malignancies.

The chemotherapy toward glioblastoma (GBM) is severely challenged by blood-brain barrier and dose-limiting toxicity. Herein, we adopt brain delivery of Plk1 inhibitor volasertib (Vol), which is highly specific and presents low off-target toxicity, as a new means to treat GBM, for which angiopep-2-docked chimaeric polypeptide polymersome (ANG-CPP) was designed and prepared from poly(ethylene glycol)-b-poly(L-tyrosine)-b-poly(L-aspartic acid) for loading Vol to its watery interior via electrostatic interactions. ANG-CPP loaded with 13.9 wt% Vol (ANG-CPP-Vol) exhibited a small size of about 76 nm, superb colloidal stability (against dilution, serum and long-term storage), and enzyme-triggered drug release behavior (about 73% of Vol released within 8 h with proteinase K). In sharp contrast to free Vol, ANG-CPP-Vol induced complete G2/M cell cycle arrest in U-87 MG GBM cells giving 7.8-times better anti-tumor activity, prolonged circulation time and largely increased GBM enrichment. ANG-CPP-Vol effectively suppressed the growth of orthotopic U-87 MG GBM and significantly boosted mice survival rate. Importantly, ANG-CPP-Vol showed further reduced toxicity over free Vol. This great safety and remarkable efficacy of ANG-CPP-Vol renders it a high potential for treating GBM.

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.

Stimuli-responsive polymer-drug conjugates (PDCs) provide promising approaches in anticancer treatment. Here, we report the synthesis and biological evaluation of PDCs made of the highly potent antimitotic agent monomethyl auristatin E conjugated to dendritic polyglycerol and dendritic polyglycerol sulfate via a reductively cleavable, self-immolative disulfide linker. Cell viability assays with the human cancer cell lines A549 (lung carcinoma) and HeLa (cervix carcinoma) revealed that the drug's cytotoxicity was reduced by conjugation to the polymers, with the sulfated conjugates being more effective than the non-sulfated ones. Kinetic studies using real-time cell analysis indicated a retarded drug release from the polymers, with a much later cytotoxic response after treatment with the non-sulfated conjugates due to less cellular uptake, as confirmed by flow cytometry and confocal laser scanning microscopy. In contrast, the non-cleavable dPGS-MMAE conjugate that was synthesized for comparison was not cytotoxic under the same conditions. Overall, reductively cleavable dPGS-SS-MMAE conjugates showed promising results in vitro and good tolerability in vivo. Further in vivo studies are planned.

Glioblastoma multiforme (GBM) poorly responds to chemotherapy owing to the existence of blood-brain barriers (BBB). It has been a long desire to develop BBB-permeable vehicles to facilitate drug targeting to GBM.

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.

There is tremendous interest in integrating CT imaging with chemotherapy; however, reported iodine-based nanosystems such as nanogels and nano-emulsions display typically reduced contrast coefficient, low drug loading and stability, and poor targetability. Here, cRGD-functionalized disulfide-crosslinked iodine-rich polymersomes (cRGD-XIPs) were designed as a novel, robust and smart theranostic agent and investigated for targeted CT imaging and chemotherapy of malignant tumors. Methods: cRGD-XIPs were prepared from co-self-assembly of poly(ethylene glycol)-b-poly(dithiolane trimethylene carbonate-co-iodinated trimethylene carbonate) (PEG-P(DTC-IC)) and cRGD-PEG-P(DTC-IC) block copolymers. In vitro and in vivo CT contrast effect of cRGD-XIPs was studied using αvβ3-overexpressing B16 melanoma as a tumor model in comparison with clinical agent iohexol. The therapeutic efficacy of doxorubicin-loaded cRGD-XIPs (cRGD-XIPs-Dox) to B16 melanoma was investigated and compared with XIPs-Dox (non-targeted), cRGD-IPs-Dox (non-crosslinked) and free Dox. Results: cRGD-XIPs were formed with 55.5 wt.% iodine and ca. 90 nm in diameter. cRGD-XIPs-Dox with a Dox loading of 15.3 wt.% bared superior colloidal stability and reduction-responsive drug release. Notably, blank cRGD-XIPs showed a maximum-tolerated dose (MTD) > 400 mg iodine equiv./kg while cRGD-XIPs-Dox had an MTD > 150 mg Dox equiv./kg, ca. 15-fold improvement over free Dox. cRGD-XIPs revealed superior CT contrast effect and achieved 46.5- and 24.0-fold better enhancement of CT imaging of B16 melanoma than iohexol at 4 h following intratumoral and intravenous injection, respectively. cRGD-XIPs-Dox displayed an elimination half-life of 6.5 h and an elevated accumulation of 6.68% ID/g in the tumors. Furthermore, cRGD-XIPs-Dox was significantly more effective than XIPs-Dox and cRGD-XPs-Dox in inhibiting growth of B16 melanoma model. Conclusion: This proof-of-concept study demonstrates that cRGD-XIPs are a robust, non-toxic and smart polymeric theranostic agent that can not only significantly enhance CT imaging of tumors but also mediate efficient tumor-targeted chemotherapy. XIPs offer a unique and safe platform for theranostic polymersomes that pre-select patients using CT imaging prior to targeted chemotherapy with the same system.

Multiple myeloma (MM) is a malignant blood cancer homing in bone marrow that is particularly hard to treat. The effective treatment for MM shall be not only MM-selective but also capable of homing to bone marrow. Herein, we report on hyaluronic acid-directed reduction-responsive chimaeric polymersomes encapsulating a key player in the NK cells, granzyme B (HA-RCP-GrB) as an artificial killer cell for targeted protein therapy of MM. Interestingly, HA-RCP-GrB displayed high MM-targetability and anti-MM activity with a remarkably low IC50 of 8.1 nM toward CD44 overexpressing LP1 human MM cells. The in vivo biodistribution studies using Cy5-labeled cytochrome C as a model protein demonstrated significantly enhanced accumulation of HA-RCP in the subcutaneous LP1 tumor as well as in the bone marrow of orthotopic LP1 MM model compared with the non-targeted RCP counterparts, confirming that HA-RCP possesses MM-selectivity and is able to deliver proteins to the bone marrow. In accordance, HA-RCP-GrB exerted significantly better suppression of subcutaneous LP1 tumor than the non-targeted RCP-GrB. More interestingly, in the orthotopic LP1 MM-bearing mice, HA-RCP-GrB led to significant survival benefits and less body weight loss over PBS and RCP-GrB. μCT analyses, H&E and TRAP staining revealed that mice treated with HA-RCP-GrB had greatly reduced osteolysis and proliferation of atypical plasma cells in the bone marrow. HA-RCP-GrB has emerged as a novel and effective treatment for multiple myeloma.

The response of malignant glioma to immunotherapy remains gloomy due to its discrete immunological environment and poor brain penetration of immunotherapeutic agents. Here, we disclose that ApoE peptide-mediated systemic nanodelivery of granzyme B (GrB) and CpG ODN co-stimulates enhanced immunotherapy of murine malignant LCPN glioma model. ApoE peptide-functionalized polymersomes encapsulating GrB (ApoE-PS-GrB) could effectively penetrate the blood-brain barrier-mimicking endothelial cell monolayer in vitro and further be taken up by LCPN cells, inducing strong immunogenic cell death (ICD). The co-administration of ApoE-PS-GrB and ApoE-PS-CpG in orthotopic LCPN glioma-bearing mice co-stimulated cytokine production, maturation of dendritic cells (DCs), infiltration of cytotoxic T lymphocytes (CTLs) while reduction of regulatory T lymphocytes (Treg) and M2 phenotype macrophages in the tumor microenvironment, leading to greatly delayed tumor progression and significantly prolonged survival time compared with all controls. The ApoE-mediated systemic nanodelivery of GrB and CpG ODN opens a new pathway for potent immunotherapy of malignant glioma.