Carrier-Free Nanomedicine for Cancer Immunotherapy

Carrier-Free Nanocombo-Sensitized Photoimmunotherapy via Activation of α2-Adrenergic Receptors

Photodynamic therapy (PDT)-based photoimmunotherapy has attracted increasing attention in the field of cancer immunotherapy. Nonetheless, monotherapy alone proves insufficient in eliciting robust and enduring tumor immunogenicity within the "cold" microenvironment of triple-negative breast cancer. Therefore, it is imperative to integrate phototherapy and immunostimulation strategies to achieve synergistic effects. Here, we developed a carrier-free nanocombo comprising a photosensitizer (chlorin e6, Ce6) and an α2-adrenergic receptor (α2-AR) agonist (guanfacine, GFC) to enhance photoimmunotherapy through α2-AR activation. Ce6 and GFC possessed the ability to self-assemble into spherical nanoparticles, with the resulting Ce6-GFC (CeG) exhibiting exceptional drug loading efficiency (approaching 100%) and long-lasting colloidal stability, along with effective in vivo tumor-targeting capabilities. Following near-infrared laser irradiation, CeG-mediated phototherapy instigated a rapid generation of reactive oxygen species, leading to membrane disruption and the release of tumor-associated antigens, thereby facilitating dendritic cell maturation. Furthermore, α2-AR agonists served to repolarize M2 tumor-associated macrophages toward the M1 phenotype via adenylyl cyclase-mediated activation of α2-AR, thereby promoting the recruitment and activation of cytotoxic T lymphocytes. As a result, the carrier-free nanocombo significantly enhanced the efficacy of photoimmunotherapy in combatting poorly immunogenic breast tumors in female mice. Our findings showcase a "killing two birds with one stone" approach that boosts tumor immunogenicity, mitigates tumor immunosuppression, and advances the field of photoimmunotherapy.

Design, Synthesis, and Anticancer Activity of Novel Enmein-Type Diterpenoid Derivatives Targeting the PI3K/Akt/mTOR Signaling Pathway

The enmein-type diterpenoids are a class of anticancer ent-Kaurane diterpnoids that have received much attention in recent years. Herein, a novel 1,14-epoxy enmein-type diterpenoid 4, was reported in this project for the first time. A series of novel enmein-type diterpenoid derivatives were also synthesized and tested for anticancer activities. Among all the derivatives, compound 7h exhibited the most significant inhibitory effect against A549 cells (IC50 = 2.16 µM), being 11.03-folds better than its parental compound 4. Additionally, 7h exhibited relatively weak anti-proliferative activity (IC50 > 100 µM) against human normal L-02 cells, suggesting that it had excellent anti-proliferative selectivity for cancer cells. Mechanism studies suggested that 7h induced G0/G1 arrest and apoptosis in A549 cells by inhibiting the PI3K/AKT/mTOR pathway. This process was associated with elevated intracellular ROS levels and collapsed MMP. In summary, these data identified 7h as a promising lead compound that warrants further investigation of its anticancer properties.

Calcium Carbonate/Polydopamine Composite Nanoplatform Based on TGF-β Blockade for Comfortable Cancer Immunotherapy

Cancer pain seriously reduces the quality of life of cancer patients. However, most research about cancer focuses solely on inhibiting tumor growth, neglecting the issue of cancer pain. Therefore, the development of therapeutic agents with both tumor suppression and cancer pain relief is crucial to achieve human-centered treatment. Here, the work reports curcumin (CUR) and ropivacaine (Ropi) coincorporating CaCO3/PDA nanoparticles (CaPNMCUR+Ropi) that realized efficient tumor immunotherapy and cancer pain suppression. The therapeutic efficiency and mechanism are revealed in vitro and in vivo. The results indicate that CaPNMCUR+Ropi underwent tumor microenvironment-responsive degradation and realized rapid release of calcium ions, Ropi, and CUR. The excessive intracellular calcium triggered the apoptosis of tumor cells, and the transient pain caused by the tumor injection was relieved by Ropi. Simultaneously, CUR reduced the levels of immunosuppressive factor (TGF-β) and inflammatory factor (IL-6, IL-1β, and TNF-α) in the tumor microenvironment, thereby continuously augmenting the immune response and alleviating inflammatory pain of cancer animals. Meanwhile, the decrease of TGF-β leads to the reduction of transient receptor potential vanilloid 1 (TRPV1) expression, thereby alleviating hyperalgesia and achieving long-lasting analgesic effects. The design of the nanosystem provides a novel idea for human-centered tumor treatment in the future.