In Situ Formed Fibrin Scaffold with Cyclophosphamide to Synergize with Immune Checkpoint Blockade for Inhibition of Cancer Recurrence after Surgery

Unsatisfied cytoreductive surgery predicts worse clinical outcomes. Previous studies have found that cyclophosphamide (CTX) is a rhythmic immune modulator that can target suppressive regulatory immune cells and meanwhile enhance effector cells. Here, a therapeutic scaffold is engineered based on a fibrin hydrogel to codeliver CTX and anti‐PD‐L1 antibody (aPDL1) for the prevention of cancer recurrence postsurgery. It is demonstrated that the sequential release of CTX and aPDL1 from the fibrin hydrogel can lead to selective depletion of regulatory T cells (Treg) in the residual tumor, which would then synergize the immune checkpoint blockade therapy. The therapeutic benefit is demonstrated in an orthotopic breast tumor and an orthotopic ovarian tumor model after incomplete resection of primary tumors. In this work, the strategy provides a clinically valuable option for preventing cancer recurrence postsurgery.     

Acetalated Dextran Nanoparticles Loaded into an Injectable Alginate Cryogel for Combined Chemotherapy and Cancer Vaccination

Vaccination represents a promising strategy for cancer therapy due to its ability to efficiently eliminate tumors from the host body and prevent their recurrence. Nevertheless, the current vaccines are still lacking efficacy. Combination therapies, such as those integrating chemotherapy with immunotherapy, represent a powerful tool to potentially circumvent this drawback. Herein, injectable alginate cryogels loaded with granulocyte‐macrophage colony‐stimulating factor and cytosine‐phosphodiester‐guanine‐rich oligonucleotides, are combined with spermine‐modified acetalated dextran nanoparticles (Sp‐AcDEX NPs), loaded with p53 activator Nutlin‐3a (Nut‐3a) for combined chemoimmunotherapy. The Sp‐AcDEX NPs are successfully loaded into the alginate cryogels and released over time. Furthermore, the delivery of the NPs from the cryogel enhances their accumulation in tumor tissue following peritumoral injection. Nut‐3a exerts toxicity towards the tumor cells and induces immunogenic cell death through the upregulation of surface calreticulin expression. Overall, this combination is a promising strategy to reduce cancer cell proliferation, induce immunogenic cell death, and accumulate drug payloads into the tumor. This approach may avoid cancer recurrence through the induction of in situ cancer vaccination mediated by antigens and danger signals released from the apoptotic cancer cells.     

Self‐Amplified Drug Delivery with Light‐Inducible Nanocargoes to Enhance Cancer Immunotherapy

Chemoimmunotherapy by systemic administration of individual regimens suffers from inconsistent pharmacokinetics profiles, low tumor specificity, and severe side effects. Despite promising nanoparticle‐based codelivery approaches in therapeutics, the pathophysiological barriers of solid tumors are a hurdle for tumor accumulation and deep penetration of the drug‐loaded nanoparticles. A light‐inducible nanocargo (LINC) for immunotherapy is reported. LINC is composed of a reduction‐responsive heterodimer of photosensitizer pheophorbide A (PPa) and indoleamine 2,3‐dioxygenase 1 (IDO‐1) inhibitor, i.e., NLG919, and a light‐activatable prodrug of oxaliplatin (OXA). LINC administrated through intravenous injection is passively accumulated at the tumor site to generate near‐infrared (NIR) fluorescence signal. Under fluorescence imaging guidance, the first‐wave of NIR laser irradiation induce reactive oxygen species (ROS) generation, trigger cleavage of the polyethylene glycol (PEG) corona, and thus promote tumor retention and deep penetration of LINC. When exposed to the second‐wave NIR laser illumination, LINC efficiently elicits the immune response and promotes intratumoral infiltration of cytotoxic T lymphocytes (CTLs). Furthermore, NLG919 delivered by LINC reverses the immunosuppressive tumor microenvironment by suppressing IDO‐1 activity. Chemoimmunotherapy with LINC inhibit the tumor growth, lung metastasis, and tumor recurrence. The light‐inducible self‐amplification strategy for improved drug delivery and immunotherapy shows potential.     

Oxygen-Evolving Manganese Ferrite Nanovesicles for Hypoxia-Responsive Drug Delivery and Enhanced Cancer Chemoimmunotherapy

Immunological tolerance induced by the hypoxic tumor microenvironment has been a major challenge for current immune checkpoint blockade therapies. Here, a hypoxia-responsive drug delivery nanoplatform is reported to promote chemoimmunotherapy of cancer by overcoming the hypoxia-induced immunological tolerance of tumors. The nanovesicles are assembled from manganese ferrite nanoparticles (MFNs) grafted with hypoxia-responsive amphiphilic polymers as the membrane, with doxorubicin hydrochloride (Dox) loaded in the aqueous cavities. Under hypoxic conditions in tumors, the nanovesicles can rapidly dissociate into individual MFNs to release Dox and induce decomposition of tumor endogenous H₂O₂ for tumor hypoxia relief. As a result, the Dox-loaded nanovesicles display remarkable suppression of primary tumor growth in combination with αPD-L1-mediated checkpoint blockade therapy. Furthermore, the modulation of the hypoxic tumor microenvironment facilitates a long-lasting immunological memory effect to prevent tumor recurrence and metastasis. Therefore, this hypoxia-responsive nanoplatform presents a potential strategy for both local tumor treatment and long-term protection against tumor recurrence.     

Codelivery of Anti‐PD‐1 Antibody and Paclitaxel with Matrix Metalloproteinase and pH Dual‐Sensitive Micelles for Enhanced Tumor Chemoimmunotherapy

Immune checkpoint blockade (ICB) is demonstrating great potential in cancer immunotherapy nowadays. Yet, the low response rate to ICB remains an urgent challenge for tumor immunotherapy. A pH and matrix metalloproteinase dual‐sensitive micellar nanocarrier showing spatio‐temporally controlled release of anti‐PD‐1 antibody (aPD‐1) and paclitaxel (PTX) in solid tumors is prepared to realize synergistic cancer chemoimmunotherapy. Antitumor immunity can be activated by PTX‐induced immunogenic cell death (ICD), while aPD‐1 blocks the PD‐1/PD‐L1 axis to suppress the immune escape due to PTX‐induced PD‐L1 up‐regulation, thus resulting in a synergistic antitumor chemoimmunotherapy. Through decoration with a sheddable polyethylene glycol (PEG) shell, the nanodrug may better accumulate in tumors to boost the synergistic antitumor treatment in a mouse melanoma model. The present study demonstrates a potent antitumor chemoimmunotherapy utilizing tumor microenvironment‐sensitive micelles bearing a sheddable PEG layer to mediate site‐specific sequential release of aPD‐1 and PTX.