IL4 receptor targeting enables nab-paclitaxel to enhance reprogramming of M2-type macrophages into M1-like phenotype via ROS-HMGB1-TLR4 axis and inhibition of tumor growth and metastasis.

Rationale: Nab-paclitaxel (Abx) is widely employed in malignant tumor therapy. In tumor cells and pro-tumoral M2-type macrophages, the IL4 receptor (IL4R) is upregulated. This study aimed to elucidate the selective delivery of Abx to M2-type macrophages by targeting IL4R and reprogramming them into an anti-tumoral M1-type. Methods: Abx was conjugated with the IL4R-binding IL4RPep-1 peptide using click chemistry (IL4R-Abx). Cellular internalization, macrophage reprogramming and signal pathways, and tumor growth and metastasis by IL4R-Abx were examined. Results: IL4R-Abx was internalized into M2 macrophages more efficiently compared to the unmodified Abx and control peptide-conjugated Abx (Ctrl-Abx), which was primarily inhibited using an anti-IL4R antibody and a receptor-mediated endocytosis inhibitor compared with a macropinocytosis inhibitor. IL4R-Abx reprogrammed the M2-type macrophages into M1-like phenotype and increased reactive oxygen species (ROS) levels and extracellular release of high mobility group box 1 (HMGB1) in M2 macrophages at higher levels than Abx and Ctrl-Abx. The conditioned medium of IL4R-Abx-treated M2 macrophages skewed M2 macrophages into the M1-like phenotype, in which an anti-HMGB1 antibody and a toll-like receptor 4 (TLR4) inhibitor induced a blockade. IL4R-Abx accumulated at tumors, heightened immune-stimulatory cells while reducing immune-suppressing cells, and hampered tumor growth and metastasis in mice more efficiently than Abx and Ctrl-Abx. Conclusions: These results indicate that IL4R-targeting allows enhancement of M2-macrophage shaping into M1-like phenotype by Abx through the ROS-HMGB1-TLR4 axis, improvement of antitumor immunity, and thereby inhibition of tumor growth and metastasis, presenting a new approach to cancer immunotherapy.

Transcytosis-Inducing Multifunctional Albumin Nanomedicines with Deep Penetration Ability for Image-Guided Solid Tumor Treatment.

Transcytosis is an active transcellular transportation pathway that has garnered interest for overcoming the limited deep penetration of nanomedicines in solid tumors. In this study, a charge-convertible nanomedicine that facilitates deep penetration into solid tumors via transcytosis is designed. It is an albumin-based calcium phosphate nanomedicine loaded with IR820 (mAlb-820@CaP) for high-resolution photoacoustic imaging and enhanced photothermal therapy. Biomineralization on the surface stabilizes the albumin-IR820 complex during circulation and provides calcium ions (Ca2+ ) for tissue penetration on degradation in an acidic environment. pH-triggered transcytosis of the nanomedicine enabled by caveolae-mediated endocytosis and calcium ion-induced exocytosis in 2D cellular, 3D spheroid, and in vivo tumor models is demonstrated. Notably, the extravasation and penetration ability of the nanomedicine is observed in vivo using a high-resolution photoacoustic system, and nanomedicine shows the most potent photothermal antitumor effect in vivo. Overall, the strategy provides a versatile theragnosis platform for both noninvasive photoacoustic imaging and high therapeutic efficiency resulting from deep penetration of nanomedicine.

Immunostimulation of tumor microenvironment by targeting tumor-associated macrophages with hypoxia-responsive nanocomplex for enhanced anti-tumor therapy.

Tumor-associated macrophages (TAMs), which dampen the therapeutic efficacy of cancer immunotherapy, are the key players in the immunosuppressive tumor microenvironment (TME). Therefore, reprogramming TAMs into tumoricidal M1 macrophages possesses considerable potential as a novel immunotherapy. However, the low bioavailability of polarization agents and limited accumulation of TAMs restrict their anti-tumor efficacy. In this study, we developed a polymer-based hypoxia-responsive nanocomplex to target TAMs in hypoxia for enhanced cancer immunotherapy. We synthesized a hypoxia-cleavable polymer poly(ethylene glycol)-azo-poly(l-lysine) (PEG-azo-PLL) and formulated a nanocomplex by simple mixing PEG-azo-PLL and poly(I:C). By mimicking in vitro hypoxia conditions, PEG-azo-PLL/poly(I:C) complexes could transform the physicochemical properties to enhance the delivery efficiency of poly(I:C) to tumor hypoxia, where M2-like TAMs are accumulated. Furthermore, PEG-azo-PLL/poly(I:C) could successfully reduce the population of M2-like TAMs in hypoxic tumors and promoted infiltration of CD8+ T cells in vivo, resulting in the favorable conversion of immunosuppressive TME. Finally, PEG-azo-PLL/poly(I:C) could elicit a significant in vivo anti-tumor effect in B16F10-bearing mice in addition to a prolonged survival time, demonstrating that the hypoxia-responsive nanocomplex PEG-azo-PLL/poly(I:C) is a promising approach for TAM reprogramming immunotherapy for solid tumors.

Harnessing the Formation of Natural Killer-Tumor Cell Immunological Synapses for Enhanced Therapeutic Effect in Solid Tumors.

The formation of an immunological synapse (IS) on recognition of a cancer cell is the main mechanism underlying the natural killer (NK)-cell-mediated killing of tumor cells. Herein, an integrative strategy for cancer therapy against solid tumors is reported, in which alterations in the cleft of IS, following the secretion of acidic granular content, are utilized as a trigger for the delivery of chemotherapeutic drugs. NK cells are decorated with the IS-environment-responsive micellar system to ensure the release of the payload when they attack cancer cells. Using this strategy, the immunological cytotoxic killing effect of NK cells against solid tumors is reinforced with the site-specific diffusion of chemotherapeutic agents. Harnessing the intrinsic mechanism for the recognition of abnormal cells and the tumor-homing effect of NK cells limit the adverse systemic effects of chemotherapeutic drugs. This approach may provide a pragmatic platform for the universal and effective utilization of IS formation.