Compressed blood and intratumoral lymphatic vessels induced by proliferated tumor cells and elevated interstitial fluid pressure produce regional hypoxic and necrotic region within tumors, which severely reduced the accessibility of immunogenic cell death (ICD) related drugs and immune-related cells. Herein, the strategy of self-oriented deep tumor delivery by circulating monocyte/macrophage was proposed. Briefly, CS-AI including an indoleamine 2,3-dioxygenase (IDO) inhibitor indoximod (IND) and hydrophilic chitosan (CSO) linked with alanine-alanine-asparagine (AAN) was prepared, which could be selectively cleaved by legumain overexpressed in macrophages and promote the collapse in structure. Then, CS-AI was modified with mannose on the surface and further encapsulated the ICD inducer doxorubicin (DOX) to obtain M-CS-AI/DOX. Upon intravenous injection, M-CS-AI/DOX was specially recognized and internalized by circulating monocyte in vivo. The formed drugs/monocyte tend to distribute in hypoxia/necrosis region guided by the homing signals released by tumor. Accumulated monocytes then further differentiated into macrophages, up-regulating the expression of legumain and promoting the sensitive-release of chemo-drug DOX, IND, and the mannose-modified CSO (M-CSO). The released IND would specifically regulate immunosuppressive tumor microenvironment, and synergistically inhibit tumor growth with immune activation elements, ICD-induced DOX, and the favorable adjuvant M-CSO. In summary, the self-oriented deep tumor delivery of legumain-cleavable nanovesicles through circulating monocyte makes it possible for reaching tumor regions inaccessible for nanoparticles and provides a novel insight for precise tumor enrichment and immune activation.

Glial cell line-derived neurotrophic factor (GDNF), a disease-modifying drug for Parkinson’s disease (PD) is in Phase 2 clinical trials (EudraCT number: 2011-003866-34), however it is administered by direct intrastriatal delivery via stereotaxy, which is accompanied with intracranial infection, brain tissue damage, and other complications. In addition, because of complex administration routes, clinical trials of GDNF have yielded contrary results, largely due to differences in dose and concentration brought by intracranial device. Herein, a small molecular agonist SC79 was screened to open blood-brain barrier (BBB) and promote GDNF liposomes to get into brain. SC79 reversibly reduces the expression of claudin-5, one of dominant tight junctions of BBB. Animal study showed SC79 promoted liposomes to enter into brain parenchyma 2.43 times more than that of the control. Motor deficits of PD mice receiving SC79 and brain-targeted GDNF liposomes were recovered by 36.70% and tyrosine hydroxylase positive neurons in striatum were restored by 39.90%. Our combination therapy effectively avoids the side effects such as secondary infection and uneven delivery caused by intracranial injection, improving patients’ compliance and providing valuable research ideas for the clinic.

Researches on indoleamine-2,3-dioxygenase-1 (IDO1), a neoplastic pathogenesis-related protein, have provided a new angle of view to regulate malignancy-related immunosuppression. However, the therapeutic efficacy of IDO1 inhibitors is subject to key limitations as both cancer and dendritic cells tend to be trapped in the IDO1-mediated immune dysfunction, which poses challenges to the inhibitory potency of drug regimens in multiple targets. Here, we report on the fabrication technique of a biomimetic nanocarrier that is endowed with the whole array of cancer cell membrane proteins for encapsulating the most used IDO1 probe indoximod (IND). By fully utilizing the homologous adhesion proteins and antigenic motifs on cytomembrane, these nanoparticulate particles are capable of infiltrating tumors and actively accumulating in cancer and dendritic cells, as well as hitching a ride on dendritic cells to tumor-draining lymph nodes. Ultimately, by increasing the distribution of drugs in both tumor cells and dendritic cells in tumor-draining lymph nodes, these formulations greatly enhance the efficacy of IND without the aid of chemotherapeutic drugs, achieving substantial control of tumor growth. Overall, this leverage of bionanotechnology maximizes the therapeutic potential of IND and can provide a theoretical reference for the clinical application of IDO1 inhibitors.

Glioblastoma (GBM) is one of the malignant brain tumors with high mortality and no curative treatments. Abnormally elevated vascular endothelial growth factor (VEGF) in GBM seriously disrupts the blood brain barrier (BBB) with an increased permeability, resulting in poor outcome and prognosis. RNAi interference has shown strong potential to inhibit VEGF expression, thus it is necessary to development an effective and safe gene delivery system possessing the ability to cross the BBB and target GBM cells. This study aims to explore the anti-GBM effect of angiopep-2 (Ap) peptide modified reactive oxygen species (ROS) cleavable thioketal (TK) linked glycolipid-like nanocarrier (CSTKSA) delivering anti-VEGF siRNA (R), termed as Ap-CSTKSA/R complexes. Ap functionalized modification produced an enhanced cellular uptake and a stronger bio-distribution of Ap-CSTKSA/R complexes in U87 MG cells and brain tumor tissues, respectively. Ap-CSTKSA/R complexes exhibited great superiority in GBM growth inhibition and finally translated into the longest survival period mainly via receptor-mediated targeting delivery, VEGF gene silencing accompanied with remarkable angiogenesis inhibition, and suppressed expression of caveolin-1 which is involved in BBB functional regulation in the occurrence and treatment of GBM. The study indicated that Ap functionalization on ROS-responsive glycolipid-like copolymer exhibits a promising and effective gene delivery platform for GBM targeted treatment.