Smart Lipid Nanoparticle that Remodels Tumor Microenvironment for Activatable H2S Gas and Photodynamic Immunotherapy

A NIR-II emissive sonosensitized biotuner for pyroptosis-enhanced sonodynamic therapy of hypoxic tumors

Pyroptosis is considered as a new way to effectively boost the immune response of tumors and inhibit tumor growth. Effective strategies to induce pyroptosis mainly rely on chemotherapeutic drugs and phototherapy, but their potential biotoxicity and phototoxicity limit their application in biomedicine. Herein, we designed a NIR-II emitting pyroptosis biotuner, Rd-TTPA, which induced pyroptosis under ultrasound irradiation to achieve pyroptosis-enhanced sonodynamic therapy (SDT) and immunogenic cell death (ICD) for tumors. Benefiting from its A-π-D1-D2 structure enhanced donor-acceptor interaction, Rd-TTPA can induce cell pyroptosis under both normoxia (21 % O2) and hypoxia (2 % O2) conditions by rapidly generating superoxide radicals (O2-•) upon ultrasound irradiation. The sonodynamic biotuner of pyroptosis overcomes the longstanding weakness of chemical drug and photosensitizer-based pyroptosis, such as drug resistance and limited penetration depth. In-depth studies demonstrated that Rd-TTPA can selectively target tumor cell mitochondria and possess excellent in vivo NIR-II fluorescence imaging capabilities. Administrating a tumor-bearing mouse model with Rd-TPPA, satisfying antitumor efficacy via pyroptosis-augmented SDT was achieved upon the guidance of NIR-II fluorescence imaging.

Near-Infrared Light-Triggered Cascade Nanosystems for Spatiotemporally Controlled Gene-Silencing and Gas Synergistic Cancer Therapy

Despite the tremendous potential of DNAzymes in gene therapy, achieving gene regulation with spatiotemporal precision and satisfactory efficacy remains a key challenge. Herein, we developed a near-infrared light (NIR)-triggered cascade effect system that enables precise spatiotemporal gene silencing and gas-synergistic cancer therapy. This nanoplatform was constructed using an enzyme-activatable DNAzyme, a nitric oxide (NO) precursor, and upconversion nanoparticles (UCNPs). The UCNPs act as light converters, facilitating the precursor to produce NO under NIR light irradiation, while the generated NO not only participates directly in gas therapy but also induces the upregulation of cytoplasmic APE1 level, resulting in enhanced DNAzyme activation and spatially controlled gene silencing. By leveraging this mechanism, cascade effects mediated gas-gene synergistic therapy is achieved through the combination of NIR light-controlled NO release and APE1-activatable gene therapy. We demonstrated that this nanoplatform enables enhanced anti-tumor effects both in vitro and in vivo. This strategy represents a critical step forward in the quest for highly targeted and efficient cancer treatments.

An electrically activable nanochip to intensify gas-ionic-immunotherapy

Excess intracellular H2S induces destructive mitochondrial toxicity, while overload of Zn2+ results in cell pyroptosis and potentiates the tumor immunogenicity for immunotherapy. However, the precise delivery of both therapeutics remains a great challenge. Herein, an electrically activable ZnS nanochip for the controlled release of H2S and Zn2+ was developed for enhanced gas-ionic-immunotherapy (GIIT). Under an electric field, a locality with particularly high concentrations of H2S and Zn2+ was established by the voltage-controlled degradation of the ZnS nanoparticles (NPs). Consequently, the ZnS nanochip-mediated gas-ionic therapy (GIT) resulted in mitochondrial membrane potential depolarization, energy generation inhibition, and oxidative stress imbalance in tumor cells. Interestingly, the cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes (cGAS-STING) signaling pathway was activated due to the mitochondrial destruction. Moreover, the released Zn2+ resulted in the increase of the intracellular Zn levels and cell pyroptosis, which enhanced the immunogenicity via the release of damage-associated molecular patterns (DAMPs). In vitro and in vivo studies revealed that the ZnS nanochip-based GIT effectively eliminated the tumors under an electric field and mobilized the cytotoxic T lymphocytes for immunotherapy. The combination with αCTLA-4 further promoted the adaptive immune response and inhibited tumor metastasis and long-term tumor recurrence. This work presented an electrically activable ZnS nanochip for combined immunotherapy, which might inspire the development of electric stimulation therapy.

Photodynamic therapy with NIR-II probes: review on state-of-the-art tools and strategies

In 2022 10% of the world's population was aged 65+, and by 2100 this segment is expected to hit 25%. These demographic changes place considerable pressure over healthcare systems worldwide, which results in an urgent need for accurate, inexpensive and non-invasive ways to treat cancers, a family of diseases correlated with age. Among the therapeutic tools that gained important attention in this context, photodynamic therapies (PDT), which use photosensitizers to produce cytotoxic substances for selectively destroying tumor cells and tissues under light irradiation, profile as important players for next-generation nanomedicine. However, the development of clinical applications is progressing at slow pace, due to still pending bottlenecks, such as the limited tissue penetration of the excitation light, and insufficient targeting performance of the therapeutic probes to fully avoid damage to normal cells and tissues. The penetration depth of long-wavelength near infrared (NIR) light is significantly higher than that of short-wavelength UV and visible light, and thus NIR light in the second window (NIR-II) is acknowledged as the preferred phototherapeutic means for eliminating deep-seated tumors, given the higher maximum permissible exposure, reduced phototoxicity and low autofluorescence, among others. Upon collective multidisciplinary efforts of experts in materials science, medicine and biology, multifunctional NIR-II inorganic or organic photosensitizers have been widely developed. This review overviews the current state-of-the art on NIR-II-activated photosensitizers and their applications for the treatment of deep tumors. We also place focus on recent efforts that combine NIR-II activated PDT with other complementary therapeutic routes such as photothermal therapy, chemotherapy, immunotherapy, starvation, and gas therapies. Finally, we discuss still pending challenges and problems of PDT and provide a series of perspectives that we find useful for further extending the state-of-the art on NIR-II-triggered PDT.

Analysis of optical properties and response mechanism of H2S fluorescent probe based on rhodamine derivatives

H2S plays a crucial role in numerous physiological and pathological processes. In this project, a new fluorescent probe, SG-H2S, for the detection of H2S, was developed by introducing the recognition group 2,4-dinitrophenyl ether. The combination of rhodamine derivatives can produce both colorimetric reactions and fluorescence reactions. Compared with the current H2S probes, the main advantages of SG-H2S are its wide pH range (5-9), fast response (30 min), and high selectivity in competitive species (including biological mercaptan). The probe SG-H2S has low cytotoxicity and has been successfully applied to imaging in MCF-7 cells, HeLa cells, and BALB/c nude mice. We hope that SG-H2S will provide a vital method for the field of biology.

H2S-Responsive NIR-II Fluorescent Nanozyme that Regulates Tumor Microenvironment for Activatable Synergistic CO Therapy/Catalytic Therapy/Immunotherapy

Nanozyme catalytic therapy triggered by the tumor microenvironment (TME)-responsive enzyme-like catalytic activities is an emerging approach for tumor treatment. However, the poor catalytic efficiency of nanozymes in tumors and the toxic side effects on normal tissues limit their further development, primarily due to the limited uptake and penetration depth of nanozyme in tumor tissues. Here, a tumor-targeting TME and electric field stimuli-responsive nanozyme (AgPt@CaCO3-FA) is developed, which is capable of catalyzing the generation of ROS to induce cell death and releasing carbon monoxide (CO) specifically in tumor tissues for on-demand CO therapy and immunotherapy. Benefiting from the endogenous H2S activated NIR-II fluorescence (FL) imaging guidance, AgPt@CaCO3-FA can be delivered into the deeper site of tumor tissues resulted from the TME regulation via generated CO during the electrolysis process to improve the catalytic efficiency of nanozymes in tumors. Moreover, CO effectively relieve immunosuppression TME via reeducating tumor-supportive M2-like macrophages to tumoricidal M1-like macrophages and induce mitochondrial dysfunction by reducing mitochondrial membrane potential, triggering tumor cells apoptosis. The enzyme-like activities combined with CO therapy arouse distinct immunogenic cell death (ICD) effect. Therefore, AgPt@CaCO3-FA permits synergistic CO gas, catalytic therapy and immunotherapy, effectively eradicating orthotopic breast tumors and preventing tumor metastasis and recurrence.

Porphyrin-based-MOF nanocomposite hydrogels for synergistic sonodynamic and gas therapy against tumor

The glioma is one of the most aggressive tumors in humans, which is difficult to eradicate clinically. Therefore, we devised a porphyrin-based metal-organic frameworks (MOFs) crosslinking hyaluronic acid (HA) hydrogel nanocomposite through double-network (Cu-MOF-S-S-HA-Gel, CSSH-Gel), which is tumor responsive for enhanced gas therapy and sonodynamic therapy (SDT). Firstly, the hydrogels show extraordinary injectability and biocompatibility, which enables intratumor administration to circumvent the danger associated with surgery. The Cu-MOF-Cys and HA-Cys are interconnected through ether and disulfide bonds to establish a dual-network gel structure. The overexpressed glutathione (GSH) in tumor microenvironment (TME) reacts with disulfide bonds to release of the nanosensitizer (Cu-MOF). Subsequently, Cu-MOF generates reactive oxygen species (ROS) upon ultrasound irradiation for SDT, and releases L-cysteine(L-Cys) catalyzed by 3-mercapto pyruvate sulfotransferase (3-MST) to generate H2S for gas therapy. The CSSH-Gel obtained excellent synergistic anti-tumor effects (82.34 % inhibition ratio in vivo), which holds tremendous promise for the advancement of minimally invasive glioma therapies.

NO- and H2S- releasing nanomaterials: A crosstalk signaling pathway in cancer

The gasotransmitters nitric oxide (NO) and hydrogen sulfide (H2S) play important roles not only in maintaining physiological functions, but also in pathological conditions and events. Importantly, these molecules show a complex interplay in cancer biology, demonstrating both tumor-promoting and anti-tumor activities depending on their concentration, flux, and the environmental redox state. Additionally, various cell types respond differently to NO and H2S. These gasotransmitters can be synergistically combined with traditional anticancer treatments such as radiotherapy, immunotherapy, chemotherapy, and phototherapy. Notably, NO, and more recently H2S, have been shown to reverse multidrug resistance. Nanomaterials to deliver NO donors and, to a lesser extent, H2S donors, have emerged as a promising approach for targeted delivery of these gasotransmitters. Nanotechnology has advanced the delivery of anticancer drugs, enhancing efficiency and reducing side effects on non-cancerous cells. This review highlights recent progress in the design of NO and H2S-releasing nanomaterials for anticancer effects. It also explores the interactions between NO and H2S, which are crucial for developing combined therapies and nanomedicines with minimal side effects.

GalNAc-modified FeS nanoparticles for specific chemodynamic and gas therapy against orthotopic hepatocellular carcinoma

GalNAc-modified ferrous sulfide nanoparticles have been developed to conduct chemodynamic and gas therapy for fighting against orthotopic hepatocellular carcinoma. This nanomedicine owns good liver targeting ability, which takes full advantage of the tumor microenvironment to ensure the therapy effect and improve the safety.

Acid-Triggered Degradation of Three-In-One Ag2S Quantum Dots for In Situ Ratiometric NIR-II Fluorescence Imaging-Guided Ion/Gas Combination Therapy

Smart theranostic nanoprobes with the integration of multiple therapeutic modalities are preferred for precise diagnosis and efficient therapy of tumors. However, it remains a big challenge to arrange the imaging and two or more kinds of therapeutic agents without weakening the intended performances. In addition, most existing fluorescence (FL) imaging agents suffer from low spatiotemporal resolution due to the short emission wavelength (<900 nm). Here, novel three-in-one Ag2S quantum dot (QD)-based smart theranostic nanoprobes were proposed for in situ ratiometric NIR-II FL imaging-guided ion/gas combination therapy of tumors. Under the acidic tumor microenvironment, three-in-one Ag2S QDs underwent destructive degradation, generating toxic Ag+ and H2S. Meanwhile, their FL emission at 1270 nm was weakened. Upon introduction of a downconversion nanoparticle (DCNP) as the delivery carrier and NIR-II FL reference signal unit, the formed Ag2S QD-based theranostic nanoprobes could achieve precise diagnosis of tumors through ratiometric NIR-II FL signals. Also, the generated Ag+ and H2S enabled specific ion/gas combination therapy toward tumors. By combining the imaging and therapeutic functions, three-in-one Ag2S QDs may open a simple yet reliable avenue to design theranostic nanoprobes.

Glutathione-Responsive and Hydrogen Sulfide Self-Generating Nanocages Based on Self-Weaving Technology To Optimize Cancer Immunotherapy

As an ideal drug carrier, it should possess high drug loading and encapsulation efficiency and precise drug targeting release. Herein, we utilized a template-guided self-weaving technology of phase-separated silk fibroin (SF) in reverse microemulsion (RME) to fabricate a kind of hyaluronic acid (HA) coated SF nanocage (HA-gNCs) for drug delivery of cancer immunotherapy. Due to the hollow structure, HA-gNCs were capable of simultaneous encapsulation of the anti-inflammatory drug betamethasone phosphate (BetP) and the immune checkpoint blockade (ICB) agent PD-L1 antibody (αPD-L1) efficiently. Another point worth noting was that the thiocarbonate cross-linkers used to strengthen the SF shell of HA-gNCs could be quickly broken by overexpressed glutathione (GSH) to reach responsive drug release inside tumor tissues accompanied by hydrogen sulfide (H2S) production in one step. The synergistic effect of released BetP and generated H2S guaranteed chronological modulation of the immunosuppressive tumor microenvironment (ITME) to amplify the therapeutic effect of αPD-L1 for the growth, metastasis, and recurrence of tumors. This study highlighted the exceptional prospect of HA-gNCs as a self-assistance platform for cancer drug delivery.

Nanoplatform-based strategies for enhancing the lethality of current antitumor PDT

Photodynamic therapy (PDT) exhibits great application prospects in future clinical oncology due to its spatiotemporal controllability and good biosafety. However, the antitumor efficacy of PDT is seriously hindered by many factors, including tumor hypoxia, limited light penetration ability, and strong defense mechanisms of tumors. Considering that it is difficult to completely solve the first two problems, enhancing the lethality of antitumor PDT has become a good idea to extend its clinical application. Herein, we summarize the nanoplatform-involved strategies to effectively amplify the tumoricidal capability of current PDT and then discuss the present bottlenecks and prospects of the nanoplatform-based PDT sensitization strategies in tumor therapy. We hope this review will provide some references for others to design high-performance PDT nanoplatforms for tumor therapy.