Hypochlorous acid selectively promotes toxicity and the expression of danger signals in human abdominal cancer cells

Magnetic Delivery of Antigen-Loaded Magnetic Liposomes for Active Lymph Node Targeting and Enhanced Anti-Tumor Immunity

Therapeutic cancer vaccines offer the greatest advantage of enhancing antigen-specific immunity against tumors, particularly for immunogenic tumors, such as melanoma. However, clinical responses remain unsatisfactory, primarily due to inadequate T cell priming and the development of acquired immune tolerance. A major obstacle lies in the inefficient uptake of antigen by peripheral dendritic cells (DCs) and their migration to lymph nodes for antigen presentation. In this context, the magnetic delivery of antigen-loaded magnetic liposomes (Ag-MLs) to actively target lymph node, is proposed. These magnetic responsive liposomes contain soluble mouse melanoma lysate and iron oxide nanoparticles in the core, along with the immunostimulatory adjuvant CpG-1826 incorporated into the lipid bilayer. When applied through magnetic targeting in the mouse melanoma model, Ag-MLs accumulate significantly in the target lymph nodes. This accumulation results in increased population of active DCs in lymph nodes and cytotoxic T lymphocytes (CTLs) within tumors, correlating with effective tumor growth inhibition. Overall, this study demonstrates the potential of magnetic targeting as an effective strategy for delivering cancer vaccines and activating the immune response, offering a novel platform for cancer immunotherapies.

BSA-AIE Nanoparticles with Boosted ROS Generation for Immunogenic Cell Death Immunotherapy of Multiple Myeloma

The main obstacle of multiple myeloma (MM) therapy is the compromised immune microenvironment, which leads to MM relapses and extramedullary disease progression. In this study, a novel strategy is reported of enhanced immunogenic cell death (ICD) immunotherapy with aggregation-induced emission (AIE) photosensitizer-loaded bovine serum albumin (BSA) nanoparticles (referred as BSA/TPA-Erdn), which can activate T cells, convert the cold tumor to hot, and reverse T cell senescence to restore the immune microenvironment for MM treatment. Loading AIE photosensitizer into the hydrophobic domain of BSA proteins significantly immobilizes the molecular geometry, which massively increases reactive oxygen species (ROS) generation and elicits a promising ICD immune response. Employing a NOD-SCID IL-2receptor gamma null mice model with MM patients' monocytes, it is shown that BSA/TPA-Erdn can simulate human dentric cell maturation, activate functional T lymphocytes, and increase additional polarization and differentiation signals to deliver a promising immunotherapy performance. Intriguingly, for the first time, it is shown that BSA/TPA-Erdn can greatly reverse T cell senescence, a main challenge in treating MM. Additionally, BSA/TPA-Erdn can effectively recruit more functional T lymphocytes into MM tumor. As a consequence, BSA/TPA-Erdn restores MM immune microenvironment and shows the best MM tumor eradication performance, which shall pave new insights for MM treatment in clinical practices.

Hypochlorous Acid: From Innate Immune Factor and Environmental Toxicant to Chemopreventive Agent Targeting Solar UV-Induced Skin Cancer

A multitude of extrinsic environmental factors (referred to in their entirety as the 'skin exposome') impact structure and function of skin and its corresponding cellular components. The complex (i.e. additive, antagonistic, or synergistic) interactions between multiple extrinsic (exposome) and intrinsic (biological) factors are important determinants of skin health outcomes. Here, we review the role of hypochlorous acid (HOCl) as an emerging component of the skin exposome serving molecular functions as an innate immune factor, environmental toxicant, and topical chemopreventive agent targeting solar UV-induced skin cancer. HOCl [and its corresponding anion (OCl-; hypochlorite)], a weak halogen-based acid and powerful oxidant, serves two seemingly unrelated molecular roles: (i) as an innate immune factor [acting as a myeloperoxidase (MPO)-derived microbicidal factor] and (ii) as a chemical disinfectant used in freshwater processing on a global scale, both in the context of drinking water safety and recreational freshwater use. Physicochemical properties (including redox potential and photon absorptivity) determine chemical reactivity of HOCl towards select biochemical targets [i.e. proteins (e.g. IKK, GRP78, HSA, Keap1/NRF2), lipids, and nucleic acids], essential to its role in innate immunity, antimicrobial disinfection, and therapeutic anti-inflammatory use. Recent studies have explored the interaction between solar UV and HOCl-related environmental co-exposures identifying a heretofore unrecognized photo-chemopreventive activity of topical HOCl and chlorination stress that blocks tumorigenic inflammatory progression in UV-induced high-risk SKH-1 mouse skin, a finding with potential implications for the prevention of human nonmelanoma skin photocarcinogenesis.

Topical hypochlorous acid (HOCl) blocks inflammatory gene expression and tumorigenic progression in UV-exposed SKH-1 high risk mouse skin

Hypochlorous acid (HOCl) is the active oxidizing principle underlying drinking water disinfection, also delivered by numerous skin disinfectants and released by standard swimming pool chemicals used on a global scale, a topic of particular relevance in the context of the ongoing COVID-19 pandemic. However, the cutaneous consequences of human exposure to HOCl remain largely unknown, posing a major public health concern. Here, for the first time, we have profiled the HOCl-induced stress response in reconstructed human epidermis and SKH-1 hairless mouse skin. In addition, we have investigated the molecular consequences of solar simulated ultraviolet (UV) radiation and HOCl combinations, a procedure mimicking co-exposure experienced for example by recreational swimmers exposed to both HOCl (pool disinfectant) and UV (solar radiation). First, gene expression elicited by acute topical HOCl exposure was profiled in organotypic human reconstructed epidermis. Next, co-exposure studies (combining topical HOCl and UV) performed in SKH-1 hairless mouse skin revealed that the HOCl-induced cutaneous stress response blocks redox and inflammatory gene expression elicited by subsequent acute UV exposure (Nos2, Ptgs2, Hmox1, Srxn1), a finding consistent with emerging clinical evidence in support of a therapeutic role of topical HOCl formulations for the suppression of inflammatory skin conditions (e.g. atopic dermatitis, psoriasis). Likewise, in AP-1 transgenic SKH-1 luciferase-reporter mice, topical HOCl suppressed UV-induced inflammatory signaling assessed by bioluminescent imaging and gene expression analysis. In the SKH-1 high-risk mouse model of UV-induced human keratinocytic skin cancer, topical HOCl blocked tumorigenic progression and inflammatory gene expression (Ptgs2, Il19, Tlr4), confirmed by immunohistochemical analysis including 3-chloro-tyrosine-epitopes. These data illuminate the molecular consequences of HOCl-exposure in cutaneous organotypic and murine models assessing inflammatory gene expression and modulation of UV-induced carcinogenesis. If translatable to human skin these observations provide novel insights on molecular consequences of chlorination stress relevant to environmental exposure and therapeutic intervention.