Delivery of siHIF-1α to Reconstruct Tumor Normoxic Microenvironment for Effective Chemotherapeutic and Photodynamic Anticancer Treatments

Phototherapy in cancer treatment: strategies and challenges

Phototherapy has emerged as a promising modality in cancer treatment, garnering considerable attention for its minimal side effects, exceptional spatial selectivity, and optimal preservation of normal tissue function. This innovative approach primarily encompasses three distinct paradigms: Photodynamic Therapy (PDT), Photothermal Therapy (PTT), and Photoimmunotherapy (PIT). Each of these modalities exerts its antitumor effects through unique mechanisms-specifically, the generation of reactive oxygen species (ROS), heat, and immune responses, respectively. However, significant challenges impede the advancement and clinical application of phototherapy. These include inadequate ROS production rates, subpar photothermal conversion efficiency, difficulties in tumor targeting, and unfavorable physicochemical properties inherent to traditional phototherapeutic agents (PTs). Additionally, the hypoxic microenvironment typical of tumors complicates therapeutic efficacy due to limited agent penetration in deep-seated lesions. To address these limitations, ongoing research is fervently exploring innovative solutions. The unique advantages offered by nano-PTs and nanocarrier systems aim to enhance traditional approaches' effectiveness. Strategies such as generating oxygen in situ within tumors or inhibiting mitochondrial respiration while targeting the HIF-1α pathway may alleviate tumor hypoxia. Moreover, utilizing self-luminescent materials, near-infrared excitation sources, non-photoactivated sensitizers, and wireless light delivery systems can improve light penetration. Furthermore, integrating immunoadjuvants and modulating immunosuppressive cell populations while deploying immune checkpoint inhibitors holds promise for enhancing immunogenic cell death through PIT. This review seeks to elucidate the fundamental principles and biological implications of phototherapy while discussing dominant mechanisms and advanced strategies designed to overcome existing challenges-ultimately illuminating pathways for future research aimed at amplifying this intervention's therapeutic efficacy.

The hybrid lipoplex induces cytoskeletal rearrangement via autophagy/RhoA signaling pathway for enhanced anticancer gene therapy

Delivering plasmid DNA (pDNA) to solid tumors remains a significant challenge due to the requirement for multiple transport steps and the need to promote delivery efficiency. Herein, we present a virus-mimicking hybrid lipoplex, composed of an arginine-rich cationic lipid, hyaluronic acid derivatives coated gold nanoparticles, and pDNA. This system induces cytoskeletal rearrangements through "outside-in" mechanical and "inside-out" biochemical signaling, overcoming intra- and intercellular barriers to enhance pDNA delivery. By modulating autophagy, RhoA signaling, and cytoskeletal dynamics, we achieve a 20-fold increase in gene expression with high tissue specificity in solid tumors. Furthermore, the system is applied to co-deliver a p53 plasmid and an MDM2 inhibitor, demonstrating significant synergistic antitumor effects in hepatocellular and lung carcinomas.

Recent Advances in Silica-Based Nanomaterials for Enhanced Tumor Imaging and Therapy

Cancer remains a formidable challenge, inflicting profound physical, psychological, and financial burdens on patients. In this context, silica-based nanomaterials have garnered significant attention for their potential in tumor imaging and therapy owing to their exceptional properties, such as biocompatibility, customizable porosity, and versatile functionalization capabilities. This review meticulously examines the latest advancements in the application of silica-based nanomaterials for tumor imaging and therapy. It underscores their potential in enhancing various cancer imaging modalities, including fluorescence imaging, magnetic resonance imaging, computed tomography, positron emission tomography, ultrasound imaging, and multimodal imaging approaches. Moreover, the review delves into their therapeutic efficacy in chemotherapy, radiotherapy, phototherapy, immunotherapy, gas therapy, sonodynamic therapy, chemodynamic therapy, starvation therapy, and gene therapy. Critical evaluations of the biosafety profiles and degradation pathways of these nanomaterials within biological environments are also presented. By discussing the current challenges and prospects, this review aims to provide a nuanced perspective on the clinical translation of silica-based nanomaterials, thereby highlighting their promise in revolutionizing cancer diagnostics, enabling real-time monitoring of therapeutic responses, and advancing personalized medicine.

Fluorinated Cell-Penetrating Peptide for Co-Delivering siHIF-1α and Sorafenib to Enhance In Vitro Anti-Tumor Efficacy

Antiangiogenic therapy with sorafenib (SF) alone is ineffective in eradicating tumors, and its long-term application can exacerbate tumor hypoxia, which in turn restricts SF's therapeutic efficacy. Here, a redox-responsive fluorinated peptide (DEN-TAT-PFC) consisting of dendritic poly-lysine, cell-penetrating peptide TAT, and perfluorocarbon was designed and synthesized to co-load siRNA-targeting hypoxia-inducible factors (siHIF-1α) and SF. The unique architecture of the peptide and fluorinated modifications enhanced the siRNA delivery efficiency, including increased siRNA binding, GSH-responsive release, cellular uptake, endosomal escape, and serum resistance. Simultaneously, the DEN-TAT-PFC/SF/siHIF-1α co-delivery system achieved efficient knockdown of HIF-1α at mRNA and protein levels, thus alleviating hypoxia and further substantially reducing VEGF expression. Additionally, the excellent oxygen-carrying ability of DEN-TAT-PFC may facilitate relief of the hypoxic microenvironment. As a result of these synergistic effects, DEN-TAT-PFC/SF/siHIF-1α exhibited considerable anti-tumor cell proliferation and anti-angiogenesis effects. Therefore, DEN-TAT-PFC can be a versatile platform for fabricating fluorine-containing drugs/siRNA complex nano-systems.

Catalase-like pleated niobium carbide MXene loaded with polythiophene for oxygenated sonodynamic therapy in solid tumor

Sonodynamic therapy (SDT), an emerging treatment for solid tumors, has the advantages of deep tissue penetration, non-invasiveness, low side effects, and negligible drug resistance. However, the hypoxic environment of deep solid tumors can discount the efficacy of oxygenated dependent SDT. Here, we synthesized a polythiophene-based sonosensitizer (PT2) and a two-dimensional pleated niobium carbide (Nb2C) Mxene. PT2 was loaded onto the surface of poly(vinylpyrrolidone) (PVP)-coated Nb2C MXene through electrostatic interaction to obtain Nb2C-PVP-PT2 nanosheets (NSs) with a high loading efficiency of 153.7%. Nb2C MXene exhibited catalase-like activity, which could catalyze hydrogen peroxide (H2O2) to produce O2, in turn alleviating tumor hypoxia and enhancing the efficacy of SDT. The depletion of H2O2 further results in abnormal cellular H2O2 levels and reduced tumor cell activity. Moreover, the decomposed NSs led to the release of the sonosensitizer PT2 that can efficiently generate both singlet oxygen and superoxide anions under ultrasound irradiation. These events led to the inhibition of DNA replication of tumor cells, causing tumor cell death, allowing for enhanced SDT efficacy.

Photothermal-responsive Prussian blue nanocages loaded with thrombin for tumor starvation therapy and photothermal therapy

The goal of inhibiting tumor growth can be achieved by cutting off the supply of nutrients in the blood vessels of a tumor site, but finding ways to effectively, accurately and safely deliver drugs that can induce vascular embolism remains a challenge. Phase change materials (PCM) can undergo solid-liquid transformation at the phase change temperature. This study reports on a near-infrared ray (NIR)-responsive nano-drug delivery platform based on Prussian blue (PB) nanoparticles. The PCM (lauric acid) can encapsulate thrombin (Thr) in the Prussian blue nanocage (PB Cage), and effectively avoid the pre-leakage of Thr during blood circulation. When the (Thr/PCM)@PB Cage is accumulated at the tumor site and irradiated with NIR, the thermal effect induced by the PB Cage causes the PCM to undergo a solid-liquid state transition, rapidly releasing the encapsulated Thr and inducing coagulation in the tumor blood vessels. Based on the safe delivery and precisely controlled release of Thr, the proliferation of tumor cells can be inhibited without damaging other tissues and organs. In addition, PB Cage-induced photothermal therapy can also ablate tumor cells. Thr-induced "starvation therapy" based on PB Cage loading provides a good reference for precise controlled-release drug delivery systems.

Hyperbaric oxygen facilitates teniposide-induced cGAS-STING activation to enhance the antitumor efficacy of PD-1 antibody in HCC

BACKGROUND

Emerging evidence indicates that the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) axis plays a pivotal role in intrinsic antitumor immunity. Previous studies demonstrate that the conventional chemotherapy agent, teniposide, effectively promotes the therapeutic efficacy of programmed cell death protein-1 antibody (PD-1 Ab) through robust cGAS-STING activation. Unfortunately, the cGAS expression of tumor cells is reported to be severely suppressed by the hypoxic status in solid tumor. Clinically, enhancing chemotherapy-induced, DNA-activated tumor STING signaling by alleviating tumor hypoxia might be one possible direction for improving the currently poor response rates of patients with hepatocellular carcinoma (HCC) to PD-1 Ab.

METHODS

Teniposide was first screened out from several chemotherapy drugs according to their potency in inducing cGAS-STING signaling in human HCC cells. Teniposide-treated HCC cells were then cultured under hypoxia, normoxia or reoxygenation condition to detect change in cGAS-STING signaling. Next, oxaliplatin/teniposide chemotherapy alone or combined with hyperbaric oxygen (HBO) therapy was administered on liver orthotopic mouse tumor models, after which the tumor microenvironment (TME) was surveyed. Lastly, teniposide alone or combined with HBO was performed on multiple mouse tumor models and the subsequent anti-PD-1 therapeutic responses were observed.

RESULTS

Compared with the first-line oxaliplatin chemotherapy, teniposide chemotherapy induced stronger cGAS-STING signaling in human HCC cells. Teniposide-induced cGAS-STING activation was significantly inhibited by hypoxia inducible factor 1α in an oxygen-deficient environment in vitro and the inhibition was rapidly removed via effective reoxygenation. HBO remarkably enhanced the cGAS-STING-dependent tumor type Ⅰ interferon and nuclear factor kappa-B signaling induced by teniposide in vivo, both of which contributed to the activation of dendritic cells and subsequent cytotoxic T cells. Combined HBO with teniposide chemotherapy improved the therapeutic effect of PD-1 Ab in multiple tumor models.

CONCLUSIONS

By combination of two therapies approved by the Food and Drug Administration, we safely stimulated an immunogenic, T cell-inflamed HCC TME, leading to further sensitization of tumors to anti-PD-1 immunotherapy. These findings might enrich therapeutic strategies for advanced HCC andwe can attempt to improve the response rates of patients with HCC to PD-1 Ab by enhancing DNA-activated STING signaling through effective tumor reoxygenation.

An Optimally Designed Engineering Exosome-Reductive COF Integrated Nanoagent for Synergistically Enhanced Diabetic Fester Wound Healing

Oxidative stress and local overactive inflammation have been considered major obstacles in diabetic wound treatment. Although antiphlogistic tactics have been reported widely, they are also challenged by pathogen contamination and compromised angiogenesis. Herein, a versatile integrated nanoagent based on 2D reductive covalent organic frameworks coated with antibacterial immuno-engineered exosome (PCOF@E-Exo) is reported to achieve efficient and comprehensive combination therapy for diabetic wounds. The E-Exo is collected from TNF-α-treated mesenchymal stem cells (MSCs) under hypoxia and encapsulated cationic antimicrobial carbon dots (CDs). This integrated nanoagent not only significantly scavenges reactive oxygen species and induces anti-inflammatory M2 macrophage polarization, but also stabilizes hypoxia-inducible factor-1α (HIF-1α). More importantly, the PCOF@E-Exo exhibits intriguing bactericide capabilities toward Gram-negative, Gram-positive, and drug-resistant bacteria, showing favorable intracellular bacterial destruction and biofilm permeation. In vivo results demonstrate that the synergetic impact of suppressing oxidative injury and tissue inflammation, promoting angiogenesis and eradicating bacterial infection, could significantly accelerate the infected diabetic fester wound healing with better therapeutic benefits than monotherapy or individual antibiotics. The proposed strategy can inspire further research to design more delicate platforms using the combination of immunotherapy with other therapeutic methods for more efficient ulcerated diabetic wounds treatments.

Conquering the Hypoxia Limitation for Photodynamic Therapy

Photodynamic therapy (PDT) has aroused great research interest in recent years owing to its high spatiotemporal selectivity, minimal invasiveness, and low systemic toxicity. However, due to the hypoxic nature characteristic of many solid tumors, PDT is frequently limited in therapeutic effect. Moreover, the consumption of O₂ during PDT may further aggravate the tumor hypoxic condition, which promotes tumor proliferation, metastasis, and invasion resulting in poor prognosis of treatment. Therefore, numerous efforts have been made to increase the O₂ content in tumor with the goal of enhancing PDT efficacy. Herein, these strategies developed in past decade are comprehensively reviewed to alleviate tumor hypoxia, including 1) delivering exogenous O₂ to tumor directly, 2) generating O₂ in situ, 3) reducing tumor cellular O₂ consumption by inhibiting respiration, 4) regulating the TME, (e.g., normalizing tumor vasculature or disrupting tumor extracellular matrix), and 5) inhibiting the hypoxia-inducible factor 1 (HIF-1) signaling pathway to relieve tumor hypoxia. Additionally, the O₂ -independent Type-I PDT is also discussed as an alternative strategy. By reviewing recent progress, it is hoped that this review will provide innovative perspectives in new nanomaterials designed to combat hypoxia and avoid the associated limitation of PDT.