Intratumoral adoptive transfer of inflammatory macrophages engineered by co-activating TLR and STING signaling pathways exhibits robust antitumor activity.

Despite the success of chimeric antigen receptor (CAR) T cells in hematologic malignancies, adoptive cell therapy (ACT) has not been effective in treating solid tumors. Here, we developed an inflammatory macrophage-based ACT to effectively treat solid tumors. We engineered inflammatory macrophages to enhance their antitumor activities, including proinflammatory cytokine secretion and co-stimulatory molecule expression by co-activating toll-like receptor and stimulator of interferon genes signaling pathways. Engineered macrophages maintain an inflammatory phenotype after their adoptive transfer into the anti-inflammatory tumor microenvironment (TME), whereas conventional inflammatory macrophages prepared using interferon-γ treatment are repolarized to an anti-inflammatory phenotype. In a mouse melanoma model, intratumoral adoptive transfer of engineered macrophages showed robust tumor growth inhibition by increasing CD8+ T cells in the TME and tumor antigen-specific CD8+ T cells in the blood. This study demonstrated that engineered inflammatory macrophages have potential as an effective ACT for treating solid tumors.

Porous Silicon-Based Nanomedicine for Simultaneous Management of Joint Inflammation and Bone Erosion in Rheumatoid Arthritis.

The lack of drugs that target both disease progression and tissue preservation makes it difficult to effectively manage rheumatoid arthritis (RA). Here, we report a porous silicon-based nanomedicine that efficiently delivers an antirheumatic drug to inflamed synovium while degrading into bone-remodeling products. Methotrexate (MTX) is loaded into the porous silicon nanoparticles using a calcium silicate based condenser chemistry. The calcium silicate-porous silicon nanoparticle constructs (pCaSiNPs) degrade and release the drug preferentially in an inflammatory environment. The biodegradation products of the pCaSiNP drug carrier are orthosilicic acid and calcium ions, which exhibit immunomodulatory and antiresorptive effects. In a mouse model of collagen-induced arthritis, systemically administered MTX-loaded pCaSiNPs accumulate in the inflamed joints and ameliorate the progression of RA at both early and established stages of the disease. The disease state readouts show that the combination is more effective than the monotherapies.

Coimmunomodulation of tumor and tumor-draining lymph nodes during in situ vaccination promotes antitumor immunity.

In situ vaccination has demonstrated the feasibility of priming local immunity for systemic antitumor responses. Although direct intratumoral (IT) delivery of adjuvant is the mainstay, tumor-draining lymph nodes (TDLNs) also play essential roles in antitumor immunity. We report that directing an adjuvant to both tumors and TDLNs during in situ vaccination can induce robust antitumor responses. Conventional IT dosing leads to tumor-limited delivery of agents; however, delivery to both tumors and TDLNs can be ensured through a micellar formation. The peritumoral delivery of micellar MEDI9197 (mcMEDI), a toll-like receptor 7/8 agonist, induced significantly stronger innate and adaptive immune responses than those on conventional dosing. Optimal dosing was crucial because excessive or insufficient accumulation of the adjuvant in the TDLNs compromised therapeutic efficacy. The combination of local mcMEDI therapy significantly improved the efficacy of systemic anti-programmed death receptor 1 therapy. These data suggest that rerouting adjuvants to tumors and TDLNs can augment the therapeutic efficacy of in situ vaccination.

Nanomedicine for the Treatment of Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune disease that results in severe inflammatory microenvironments in the joint tissues. In clinics, disease-modifying antirheumatic drugs (DMARDs) are generally prescribed to patients with RA, but their long-term use often shows toxicity in some organs such as the gastrointestinal system, skin, and kidneys and immunosuppression-mediated infection. Nanomedicine has emerged as a new therapeutic strategy to efficiently localize the drugs in inflamed joints for the treatment of RA. In this Review, we introduce recent research in the area of nanomedicine for the treatment of RA and discuss how the nanomedicine can be used to deliver therapeutic agents to the inflamed joints and manage the progression of RA, particularly focusing on targeted delivery, controlled drug release, and immune modulation.

Polypeptide-Based K+ Ionophore as a Strong Immunogenic Cell Death Inducer for Cancer Immunotherapy.

Immunogenic cell death (ICD) is a key factor for generating antitumor immunity. Endoplasmic reticulum (ER) stress triggers the release of damage-associated molecular patterns (DAMPs), thus inducing immunogenicity. We developed a polypeptide-based K+ ionophore that perturbed ion homeostasis and elicited a prolonged ER stress. The ER stress not only fosters an oxidative environment that activates mitochondria-dependent apoptosis pathways but also drives immune responses by releasing DAMPs. The ionophore suppressed tumor proliferation in vitro and in vivo based on the pro-apoptotic activity and immunogenicity.

Management of lymph node metastasis via local chemotherapy can prevent distant metastasis and improve survival in mice.

Management of lymph node metastasis (LNM) by conventional modalities such as radiotherapy and systemic chemotherapy exhibit limited LNM selectivity and therefore can cause off-target adverse events. While development of LNM-specific drug delivery systems has tremendous potential to provide a safer treatment modality and improve cancer treatment, precise assessment of therapeutic efficacy and implications has been challenging due to lack of a suitable preclinical model. Here, we established an experimental LNM model in mice by directly seeding cancer cells into a lymph node (LN), which developed spontaneous LNM-borne distant metastasis (DM) in the absence of a primary tumor. In the model, early, but not late, management of LNM before thereof tumor cells systemically disseminated could confer significant survival benefit, which suggests that time to LNM management is critical. Systematic comparative assessment of various local drug delivery systems revealed that a micellar formulation could achieve highly LNM-specific delivery of a chemotherapeutic agent, which was superior to systemic chemotherapy, effective at a very low dose, and safe. This study suggests not only that the experimental LNM model provides a useful preclinical model to study LNM management and its therapeutic implications but also that micelles are a promising drug delivery system for LNM management via local administration.

Liposomal borrelidin for treatment of metastatic breast cancer.

Borrelidin is an inhibitor of threonyl-tRNA synthetase with both anticancer and antiangiogenic activities. Although borrelidin could be a potent drug that can treat metastatic cancer through synergistic therapeutic effects, its severe liver toxicity has limited the use for cancer therapeutics. In this study, we developed a liposomal formulation of borrelidin to treat metastatic breast cancer effectively through its combined anticancer and antiangiogenic effects while reducing the potential liver toxicity. The liposomal formulation was optimized to maximize loading stability and efficiency of lipophilic borrelidin in the liposomal membrane and its delivery efficiency to primary tumor in a mouse model of metastatic breast cancer. Liposomal borrelidin showed significant in vitro therapeutic effects on proliferation and migration of tumor cells and angiogenesis of endothelial cells. Furthermore, liposomal borrelidin exhibited superior inhibitory effects on primary tumor growth and lung metastasis in vivo compared to free borrelidin. More importantly, liposomal borrelidin did not induce any significant systemic toxicity in the mouse model after multiple injections.

Effective Retinal Penetration of Lipophilic and Lipid-Conjugated Hydrophilic Agents Delivered by Engineered Liposomes.

Efficient delivery of drugs to the retina is critical but difficult to achieve with current methods. There have been a number of attempts to use intravitreal injection of liposomes, artificial vesicles composed of a phospholipid bilayer, to overcome the limitations of conventional intravitreal injection (short retention time, toxicity, poor penetration, etc.). Here, we report an optimal liposomal formulation that can diffuse through the vitreous humor, deliver the incorporated agents to all retinal layers effectively, and maintain them for a relatively long time. We first delivered lipophilic compounds and phospholipid-conjugated hydrophilic agents to the inner limiting membrane using engineered liposomes. Subsequently, the agents penetrated the retina deeply, presumably via extracellular vesicles, nanoscale vesicles secreted from retinal-associated cells. These results suggest that this engineered liposomal formulation can leverage the biological transport system for effective retinal penetration of lipophilic and lipid-conjugated agents.

Cellular Engineering with Membrane Fusogenic Liposomes to Produce Functionalized Extracellular Vesicles.

Engineering of extracellular vesicles (EVs) without affecting biological functions remains a challenge, limiting the broad applications of EVs in biomedicine. Here, we report a method to equip EVs with various functional agents, including fluorophores, drugs, lipids, and bio-orthogonal chemicals, in an efficient and controlled manner by engineering parental cells with membrane fusogenic liposomes, while keeping the EVs intact. As a demonstration of how this method can be applied, we prepared EVs containing azide-lipids, and conjugated them with targeting peptides using copper-free click chemistry to enhance targeting efficacy to cancer cells. We believe that this liposome-based cellular engineering method will find utility in studying the biological roles of EVs and delivering therapeutic agents through their innate pathway.

Immunoglobulin Fc-fused, neuropilin-1-specific peptide shows efficient tumor tissue penetration and inhibits tumor growth via anti-angiogenesis.

Neuropilin-1 (NRP1) receptor, involved in vascular endothelial growth factor (VEGF)-mediated vascular permeability and tumor angiogenesis, is targeted by peptides that bind to its VEGF-binding site. However, these peptides also cross-react with the structurally related receptor, NRP2. Here, we describe an immunoglobulin Fc-fused peptide, Fc-TPP11, which specifically binds to the VEGF-binding site of NRP1 with approximately 2nM affinity, but negligibly to that of NRP2. Fc-TPP11 triggered NRP1-dependent signaling, enhanced vascular permeability via vascular endothelial (VE)-cadherin downregulation, and increased paracellular permeability via E-cadherin downregulation in tumor tissues. Fc-TPP11 also significantly enhanced the tumor penetration of co-injected anti-cancer drug, doxorubicin, leading to the improved in vivo anti-tumor efficacy. Fc-TPP11 was easily adapted to the full-length anti-epidermal growth factor receptor (EGFR) monoclonal antibody (mAb) cetuximab (Erbitux), cetuximab-TPP11, exhibiting more than 2-fold improved tumor penetration than the parent cetuximab. Fc-TPP11 exhibited a similar whole-body half-life to that of intact Fc in tumor bearing mice. In addition to the tumor-penetrating activity, Fc-TPP11 suppressed VEGF-dependent angiogenesis by blocking VEGF binding to NRP1, thereby inhibiting tumor growth without promoting metastasis in the mouse model. Our results show that NRP1-specific, high-affinity binding of Fc-TPP11, is useful to validate NRP1 signaling, independent of NRP2. Thus, Fc-TPP11 can be used as a tumor penetration-promoting agent with anti-angiogenic activity or directly adapted to mAb-TPP11 format for more potent anti-cancer antibody therapy.

Liposome-based engineering of cells to package hydrophobic compounds in membrane vesicles for tumor penetration.

Natural membrane vesicles (MVs) derived from various types of cells play an essential role in transporting biological materials between cells. Here, we show that exogenous compounds are packaged in the MVs by engineering the parental cells via liposomes, and the MVs mediate autonomous intercellular migration of the compounds through multiple cancer cell layers. Hydrophobic compounds delivered selectively to the plasma membrane of cancer cells using synthetic membrane fusogenic liposomes were efficiently incorporated into the membrane of MVs secreted from the cells and then transferred to neighboring cells via the MVs. This liposome-mediated MV engineering strategy allowed hydrophobic photosensitizers to significantly penetrate both spheroids and in vivo tumors, thereby enhancing the therapeutic efficacy. These results suggest that innate biological transport systems can be in situ engineered via synthetic liposomes to guide the penetration of chemotherapeutics across challenging tissue barriers in solid tumors.