MTH1 inhibitor amplifies the lethality of reactive oxygen species to tumor in photodynamic therapy

A core-shell structured biphasic microneedle system as an elite squad for combating melanoma with "three-in-one" therapeutic power

Achieving optimal therapeutic outcomes with microneedle (MN) technology requires a high drug payload, tunable mechanical strength, and robust drug stability-key attributes in demand for transdermal drug delivery. This work introduces a core-shell structured biphasic MN system designed to combat melanoma with "three-in-one" therapeutic power. The MN base, made of water-insoluble poly(methyl methacrylate), forms a biphasic interface with the needle body. Acting as a "shield", the base effectively prevents drug migration and enhances the drug-loading capacity of the needle body. The needle body features a core-shell design, with a shell composed of photo-cross-linked hydrogel. This shell serves as a "spear" to optimize mechanical properties of MNs, efficiently piercing the skin barrier. Meanwhile, the core section of MN, constructed from hyaluronic acid, acts as a "bow and arrow" to preserve the bioactivity of chlorin e6 nanoparticles for launching an effective "attack" on melanoma cells through photodynamic therapy. The MN system demonstrates exceptional mechanical performance and enhanced anticancer efficacy against melanoma cells both in vitro and in vivo. In summary, this study introduces a new "elite squad" strategy that integrates three critical functionalities into a single MN platform, offering significant potential for treating melanoma and other malignant skin conditions.

Exosome-decorated bio-heterojunctions reduce heat and ROS transfer distance for boosted antibacterial and tumor therapy

Photothermal and photodynamic therapies represent effective modalities for combatting bacteria and tumor cells. However, therapeutic outcomes are constrained by limitations related to the heat and reactive oxygen species (ROS) transfer distance from photosensitizers to targets. To address this issue, we have devised and developed exosome-decorated bio-heterojunctions (E-bioHJ) consisted of MXene (Ti3C2), liquid metal (LM) and exosomes sourced from CT26 cells to enhance the phototherapeutic consequences. Engineering E-bioHJ enhances phototherapeutic effect in antibacterial and anti-tumor treatment, which is ascribed to reducing transfer distance of the heat and ROS. When adorned with exosomes, E-bioHJ is targetedly delivered into the cytoplasm of tumor cells to generate amount heat and ROS under 808 nm near-infrared radiation, which further induces mitochondrial dysfunction and apoptosis/necroptosis. As envisaged, this study presents a novel tactic to enhance the antibacterial and anti-tumor efficacy of biomaterials through reducing the heat and ROS delivery travel distance.

DNA-mediated self-assembly oxidative damage amplifier combined with copper and MTH1 inhibitor for cancer therapy

Chemo-dynamic therapy (CDT) has a great potential in tumor extirpation. It entails producing hypertoxic reactive oxygen species (ROS) that damage the DNA of tumor cells and other biomacromolecules. However, the efficiency of CDT is severely hampered by the massive presence of glutathione (GSH) in tumor cells and the interference of ROS defense systems, such as Mutt homolog 1 (MTH1) protein sanitizes ROS-oxidized nucleotide pools. In this research, DNA-mediated self-assembly nanoparticles (HTCG@TA NPs) were engineered with high-performance amplified oxidative damage and gene therapy effect for synergistic anti-tumor treatment. Cu2+ was converted into Cu + by redox reactions to deplete GSH while H2O2 was catalyzed to generate hydroxyl radicals (·OH). As a result, the ROS level was evidently improved. Moreover, controllable-released TH588 prevented MTH1-mediated DNA repairing, thus aggravated oxidative damage to tumor cells. Meanwhile, the released functional nucleic acid G3139 downregulated the expression of Bcl-2, and accelerated the apoptosis of tumor cells. In conclusion, the HTCG@TA demonstrated significant effect in oxidative damage amplification and tumor inhibition both in vitro and in vivo, which has provided a new outlook for the clinical application of chemo-dynamic tumor treatment and synergistic gene therapy with self-delivery nanoplatforms.

An Oxidative Stress Nano-Amplifier for Improved Tumor Elimination and Combined Immunotherapy

Amplifying oxidative stress to disrupt intracellular redox homeostasis can accelerate tumor cell death. In this work, an oxidative stress amplifier (PP@T) is prepared for enhanced tumor oxidation therapy to reduce tumor growth and metastases. The nano-amplifier has been successfully constructed by embedding MTH1 inhibitor (TH588) in the PDA-coated porphyrin metal-organic framework PCN-224. The controllable-released TH588 is demonstrated from pores can hinder MTH1-mediated damage-repairing process by preventing the hydrolysis of 8-oxo-dG, thereby amplifying oxidative stress and exacerbating the oxidative DNA damage induced by the sonodynamic therapy of PP@T under ultrasound irradiation. Furthermore, PP@T can effectively induce immunogenic cell death to trigger systemic anti-tumor immune response. When administered in combination with immune checkpoint blockade, PP@T not only impedes the progression of the primary tumor but also achieves obvious antimetastasis in breast cancer murine models, including orthotopic and artificial whole-body metastasis models. Furthermore, the nanoplatform also provides photoacoustic imaging for in vivo treatment guidance. In conclusion, by amplifying oxidative stress and reactive oxygen species sensitized immunotherapy, this image-guided nanosystem shows potential for highly specific, effective combined therapy against tumor cells with negligible side-effects to normal cells which will provide a new insight for precise tumor treatment.

Utilizing stimuli-responsive nanoparticles to deliver and enhance the anti-tumor effects of bilirubin

Bilirubin (BR) is among the most potent endogenous antioxidants that originates from the heme catabolic pathway. Despite being considered as a dangerous and cytotoxic waste product at high concentrations, BR has potent antioxidant effects leading to the reduction of oxidative stress and inflammation, which play an important role in the development and progression of cancer. The purpose of this study is to introduce PEGylated BR nanoparticles (NPs), themselves or in combination with other anti-cancer agents. BR is effective when loaded into various nanoparticles and used in cancer therapy. Interestingly, BRNPs can be manipulated to create stimuli-responsive carriers providing a sustained and controlled, as well as on-demand, release of drug in response to internal or external factors such as reactive oxygen species, glutathione, light, enzymes, and acidic pH. This review suggests that BRNPs have the potential as tumor microenvironment-responsive delivery systems for effective targeting of various types of cancers.

Nanomaterial-based regulation of redox metabolism for enhancing cancer therapy

Altered redox metabolism is one of the hallmarks of tumor cells, which not only contributes to tumor proliferation, metastasis, and immune evasion, but also has great relevance to therapeutic resistance. Therefore, regulation of redox metabolism of tumor cells has been proposed as an attractive therapeutic strategy to inhibit tumor growth and reverse therapeutic resistance. In this respect, nanomedicines have exhibited significant therapeutic advantages as intensively reported in recent studies. In this review, we would like to summarize the latest advances in nanomaterial-assisted strategies for redox metabolic regulation therapy, with a focus on the regulation of redox metabolism-related metabolite levels, enzyme activity, and signaling pathways. In the end, future expectations and challenges of such emerging strategies have been discussed, hoping to enlighten and promote their further development for meeting the various demands of advanced cancer therapies. It is highly expected that these therapeutic strategies based on redox metabolism regulation will play a more important role in the field of nanomedicine.

An Integrated Nanoplatform via Dual Channel Excitation for Both Precise Fluorescence Imaging and Photodynamic Therapy of Orthotopic Breast Tumor in NIR-II Region

Although research on photodynamic therapy (PDT) of malignant tumor has made considerable progress in recent years, it is a remaining challenge to extend PDT to the second near-infrared window (NIR-II) along with real-time and accurate NIR-II fluorescence imaging to determine drug enrichment status and achieve high treatment efficacy. In this work, lanthanide nanoparticles (Ln NPs)-based nanoplatform (LCR) equipped with photosensitizer Chlorin e6 (Ce6) and targeting molecular NH2-PEG1000-cRGDfK are developed, which can achieve NIR-II photodynamic therapy (PDT) and NIR-II fluorescence imaging by dual channel excitation. Under 808 nm excitation, Nd3+ in the outer layer can absorb the energy and transfer inward to emit strong NIR-II emissions (1064 and 1525 nm). Due to the low background noise of NIR-II light and the targeting effect of NH2-PEG1000-cRGDfK, LCR can recognize tiny tumor tissue (≈3 mm) and monitor drug distribution in vivo. Under 1530 nm excitation, internal Er3+ can be self-sensitized, generating intense upconversion emission (662 nm) that can effectively activate Ce6 for in vivo PDT due to the deep tissue penetration of NIR-II light. This study provides a paradigm of theranostic nanoplatform for both real-time fluorescence imaging and PDT of orthotopic breast tumor in NIR-II window.

An "AND" logic gate-based supramolecular therapeutic nanoplatform for combatting drug-resistant non-small cell lung cancer

Despite targeted therapies like epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), non-small cell lung cancer (NSCLC) remains a clinical challenge due to drug resistance hampering their efficacy. Here, we designed an "AND" logic gate-based supramolecular therapeutic platform (HA-BPY-GEF-NPs) for the treatment of EGFR-TKI resistant NSCLC. This system integrates both internal and external stimuli-responsive mechanisms that need to be activated in a preset sequence, enabling it to precisely control drug release behavior for enhancing therapeutic precision. By programming the system to respond to sequential near-infrared (NIR) irradiation and enzyme (cathepsin B) inputs, the release of gefitinib is effectively confined to the tumor region. Moreover, the NIR irradiation induces reactive oxygen species production, suppressing tumor growth and inhibiting bypass signaling pathways. The designed drug delivery system offers a highly controlled and targeted therapeutic approach, effectively inhibiting tumor growth, suppressing bypass signaling pathways, and overcoming EGFR-TKI resistance, thus offering a potential solution for maximizing therapeutic benefits.

Tumor oxygen microenvironment-tailored electron transfer-type photosensitizers for precise cancer therapy

The oxygen level in a tumor typically exhibits complex characteristics, ranging from mild hypoxia to moderate and even severe hypoxia. This poses significant challenges for the efficacy of photodynamic therapy, where oxygen is an essential element. Herein, we propose a novel therapeutic strategy and develop a series of lipid droplet-targeting photosensitive dyes (Ser-TPAs), i.e., in situ synergistic activation of two different electron transfer-type reactions. Based on this strategy, Ser-TPAs can synergistically generate O2˙- and nitrogen radicals regardless of the oxygen content, which results in a sustained high concentration of strongly oxidizing substances in the lipid droplets of cancer cells. As such, Ser-TPAs exhibited inhibitory activity against tumor growth in vivo, resulting in a significant reduction in tumor volume (V experimental group : V control group ≈ 0.07). This strategy offers a conceptual framework for the design of innovative photosensitive dyes that are suitable for cancer therapy in complex oxygen environments.

Quasi-intrinsic thiobase derivatives as potential targeted photosensitizers in two-photon photodynamic therapy

In this study, a set of potential quasi-intrinsic photosensitizers for two-photon photodynamic therapy (PDT) are proposed based on the unnatural 2-amino-8-(1'-β-ᴅ-2'-deoxyribofuranosyl)-imidazo[1,2-ɑ]-1,3,5-triazin-4(8H)-one (P), which is paired with the 6-amino-5-nitro-3-(1'-β-ᴅ-2'-deoxyribofuranosyl)-2(1H)-pyridone (Z) and can specifically recognize breast and liver cancer cells. Herein, the effects of sulfur substitution and electron-donating/electron-withdrawing groups on the photophysical properties in aqueous solution are systematically investigated. The one- and two-photon absorption spectra evidence that the modifications could result in red-shifted absorption wavelength and large two-photon absorption cross-section, which contributes to selective excitation and provides effective PDT for deep-seated tissues. To ensure the efficient triplet state population, the singlet-triplet energy gaps and spin-orbit coupling constants were examined, which is responsible for a rapid intersystem crossing rate. Furthermore, these thiobase derivatives are characterized by the long-lived T1 state and the large energy gap for radiationless transition to ensure the generation of cytotoxic singlet oxygen.

Cationic Polythiophene as Gene Carrier and Sonosensitizer for Sonodynamic Synergic Gene Therapy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most lethal and highly malignant tumors. Sonodynamic therapy (SDT) is a new cancer treatment method. One of its unique advantages lies in the treatment of deep tumors due to its excellent tissue penetration ability caused by ultrasound (US). However, most sonosensitizers suffer from weak sonodynamic activity and poor tumor-targeting ability. In addition, small interfering RNA (siRNA) is a promising anticancer drug, and the efficacy of siRNA-based gene therapy largely depends on the cell impermeability of the gene carrier. Here, we designed and synthesized a cationic polythiophene derivative (PT2) that can be used as a siRNA carrier for gene therapy. Moreover, PT2 could generate singlet oxygen (1O2) and hydroxyl radicals (O2•-) under US irradiation, which suggests that PT2 could be used for SDT. Our study discovered that NUDT1 promoted HCC proliferation and inhibited intracellular ROS production. Therefore, si-NUDT1 was designed and synthesized. NUDT1 silencing can inhibit the proliferation of tumor cells and increase the production of intracellular ROS to further improve the efficacy of SDT. Then, si-NUDT1 assembled with PT2 and DSPE-PEG-FA to prepare a novel tumor-targeting nanodrug (PT2-siRNA@PEG-FA) for synergic SDT and gene therapy of HCC.

Photoactivated full-API nanodrug (FAND): harnessing transition metal complexes and MTH1 inhibitor for enhanced DNA damage in cancer cells

The effectiveness of photodynamic therapy (PDT) has been greatly restricted by the hypoxic tumor microenvironment and the susceptible resistance of monotherapy. Although nanodrugs based on transition metal complexes capable of integrating PDT with photoactivated chemotherapy (PACT) have garnered tremendous attention as promising candidates for overcoming the above limitations, the therapeutic efficacy of these nanodrugs is still hampered by inadequate loading of active pharmaceutical ingredients (APIs) and the inherent ability of cancer cells to repair damaged DNA. Herein, we developed a photoactivated full-API nanodrug, Ru-T FAND, by one-step self-assembly of RuDPB and TH287. By virtue of its 100 wt% API content and favorable stability in water, the Ru-T FAND exhibited improved cellular uptake behavior and intracellular 1O2 generation. Attractively, the Ru-T FAND with triple anti-cancer modalities can photogenerate 1O2, photo-release DPB ligand and inhibit the repair of DNA damage, ultimately enhancing its phototherapeutic effect on cancer cells. Importantly, the uncaged DPB ligand from RuDPB emits red fluorescence, enabling real-time monitoring of the drug's absorption, distribution and efficacy. Collectively, the presented photoactivated Ru-T FANDs with multiple anti-cancer mechanisms will expand new horizons for the development of safe, efficient and synergistic tumor phototherapy strategies.

MTH1 inhibition synergizes with ROS-inducing agents to trigger cervical cancer cells undergoing parthanatos

Cervical cancer cells possess high levels of reactive oxygen species (ROS); thus, increasing oxidative stress above the toxicity threshold to induce cell death is a promising chemotherapeutic strategy. However, the underlying mechanisms of cell death are elusive, and efficacy and toxicity issues remain. Within DNA, 8-oxo-7,8-dihydroguanine (8-oxoG) is the most frequent base lesion repaired by 8-oxoguanine glycosylase 1 (OGG1)-initiated base excision repair. Cancer cells also express high levels of MutT homolog 1 (MTH1), which prevents DNA replication-induced incorporation of 8-oxoG into the genome by hydrolyzing 8-oxo-7,8-dihydro-2'-deoxyguanosine 5'-triphosphate (8-oxo-dGTP). Here, we revealed that ROS-inducing agents triggered cervical cancer to undergo parthanatos, which was mainly induced by massive DNA strand breaks resulting from overwhelming 8-oxoG excision by OGG1. Furthermore, the MTH1 inhibitor synergized with a relatively low dose of ROS-inducing agents by enhancing 8-oxoG loading in the DNA. In vivo, this drug combination suppressed the growth of tumor xenografts, and this inhibitory effect was significantly decreased in the absence of OGG1. Hence, the present study highlights the roles of base repair enzymes in cell death induction and suggests that the combination of lower doses of ROS-inducing agents with MTH1 inhibitors may be a more selective and safer strategy for cervical cancer chemotherapy.

Pt-Decorated Gold Nanoflares for High-Fidelity Phototheranostics: Reducing Side-Effects and Enhancing Cytotoxicity toward Target Cells

Functionalized with the Au-S bond, gold nanoflares have emerged as promising candidates for theranostics. However, the presence of intracellular abundantly biothiols compromises the conventional Au-S bond, leading to the unintended release of cargoes and associated side-effects on non-target cells. Additionally, the hypoxic microenvironment in diseased regions limits treatment efficacy, especially in photodynamic therapy. To address these challenges, high-fidelity photodynamic nanoflares constructed on Pt-coated gold nanoparticles (Au@Pt PDNF) were communicated to avoid false-positive therapeutic signals and side-effects caused by biothiol perturbation. Compared with conventional photodynamic gold nanoflares (AuNP PDNF), the Au@Pt PDNF were selectively activated by cancer biomarkers and exhibited high-fidelity phototheranostics while reducing side-effects. Furthermore, the ultrathin Pt-shell catalysis was confirmed to generate oxygen which alleviated hypoxia-related photodynamic resistance and enhanced the antitumor effect. This design might open a new venue to advance theranostics performance and is adaptable to other theranostic nanomaterials by simply adding a Pt shell.

Hepatic Stellate Cell-Targeting Micelle Nanomedicine for Early Diagnosis and Treatment of Liver Fibrosis

Diagnosing and treating liver fibrosis is a challenging yet crucial endeavor due to its complex pathogenesis and risk of deteriorating into cirrhosis, liver failure, and even hepatic cancer. Herein, a silica cross-linked micelles (SCLMs) based nano-system is developed for both diagnosing and treating liver fibrosis. The SCLMs are first modified with peptide CTCE9908 (CT-SCLMs) and can actively target CXCR4, which is overexpressed in activated hepatic stellate cells (HSCs). To enable diagnosis, an ONOO--responded near-infrared fluorescent probe NOF2 is loaded into the CT-SCLMs. This nano-system can target the aHSCs and diagnose the liver fibrosis particularly in CCl4-induced liver damage, by monitoring the reactive nitrogen species. Furthermore, a step is taken toward treatment by co-encapsulating two anti-fibrosis drugs, silibinin and sorafenib, within the CT-SCLMs. This combined approach results in a significant alleviation of liver injury. Symptoms associated with liver fibrosis, such as deposition of collagen, expression of hydroxyproline, and raised serological indicators show notable improvement. In summary, the CXCR4-targeted nano-system can serve as a promising theragnostic system of early warning and diagnosis for liver fibrosis, offering hope against progression of this serious liver condition.

A Fe(III) intercalated clay nanoplatform for combined chemo/chemodynamic therapy

A Fe(III) intercalated montmorillonite nanoplatform (Fe-MMT) was engineered for doxorubicin (DOX) loading. The constructed Fe-MMT/DOX nanoplatform could not only improve the production of H2O2 to enhance chemodynamic therapy but interfere with DNA damage repair to amplify the efficacy of DOX, proving an ideal combination of chemotherapy and chemodynamic therapy.

Long-circulating nanoparticles as passive targeting nanocarriers for the treatment of thrombosis

Thrombosis is the major cause of cardiovascular diseases. Only a small subset of patients could benefit from thrombolytic therapy due to the high bleeding risk brought about by the repeated administration of thrombolytic drugs. Nanoparticles with targeting ligands have been developed as nanocarriers of thrombolytic drugs to deliver the drug to the thrombus through active targeting. However, the passive targeting effect of nanoparticles on the thrombus is yet to be investigated. Herein, we prepared silica cross-linked micelles (SCLMs) with a long blood circulation half-life as drug carriers to target the thrombus through passive targeting. Compared with SCLMs modified with an active targeting ligand cRGD, the SCLMs exhibited similar targeting behavior to the thrombus in vivo. Loaded with the thrombolytic drug tirofiban, the passive targeting SCLMs showed a comparable therapeutic effect to cRGD-modified SCLMs in a mice model with pulmonary embolism and arterial thrombosis.

Reversing Resistance of Cancer Stem Cells and Enhancing Photodynamic Therapy Based on Hyaluronic Acid Nanomicelles for Preventing Cancer Recurrence and Metastasis

Photodynamic therapy (PDT) is a promising approach for tumor treatment; however, the therapeutic resistance of cancer stem cells (CSCs) severely limits its efficacy and easily lead to recurrence. Herein, a hyaluronic acid (HA)-Ce6-Olaparib (OLA) micelle (HCCO) is developed, which combines the CSC targeting of HA, the PDT effect of Ce6, and the DNA damage repair inhibition of OLA. More importantly, HCCO induces immunogenic cell death (ICD) effects, promotes dendritic cells maturation, and alleviates myeloid-derived suppressor cells (MDSCs) infiltration to reverse CSC resistance. As a result, HCCO not only significantly inhibits the growth of 4T1 breast cancer cells and CSCs in vitro, but also effectively inhibits tumor recurrence and metastasis in vivo. This study provides a novel strategy for preventing tumor recurrence and metastasis by the combination of inhibiting DNA damage repair, reversing CSC resistance, and enhancing PDT.

Targeting the nucleic acid oxidative damage repair enzyme MTH1: a promising therapeutic option

The accumulation of reactive oxygen species (ROS) plays a pivotal role in the development of various diseases, including cancer. Elevated ROS levels cause oxidative stress, resulting in detrimental effects on organisms and enabling tumors to develop adaptive responses. Targeting these enhanced oxidative stress protection mechanisms could offer therapeutic benefits with high specificity, as normal cells exhibit lower dependency on these pathways. MTH1 (mutT homolog 1), a homolog of Escherichia coli's MutT, is crucial in this context. It sanitizes the nucleotide pool, preventing incorporation of oxidized nucleotides, thus safeguarding DNA integrity. This study explores MTH1's potential as a therapeutic target, particularly in cancer treatment, providing insights into its structure, function, and role in disease progression.

pH-Responsive Upconversion Mesoporous Silica Nanospheres for Combined Multimodal Diagnostic Imaging and Targeted Photodynamic and Photothermal Cancer Therapy

Photodynamic therapy (PDT) and photothermal therapy (PTT) have gained considerable attention as potential alternatives to conventional cancer treatments. However, these approaches remain limited by low solubility, poor stability, and inefficient targeting of many common photosensitizers (PSs) and photothermal agents (PTAs). To overcome the aforementioned limitations, we engineered biocompatible and biodegradable tumor-targeted upconversion nanospheres with imaging capabilities. The multifunctional nanospheres consist of a sodium yttrium fluoride core doped with lanthanides (ytterbium, erbium, and gadolinium) and the PTA bismuth selenide (NaYF4:Yb/Er/Gd,Bi2Se3) enveloped in a mesoporous silica shell that encapsulates a PS, chlorin e6 (Ce6), within its pores. NaYF4:Yb/Er converts deeply penetrating near-infrared (NIR) light to visible light, which excites Ce6 to generate cytotoxic reactive oxygen species (ROS), while Bi2Se3 efficiently converts absorbed NIR light to heat. Additionally, Gd enables magnetic resonance imaging of the nanospheres. The mesoporous silica shell is coated with DPPC/cholesterol/DSPE-PEG to retain the encapsulated Ce6 and prevent serum protein adsorption and macrophage recognition that hinder tumor targeting. Finally, the coat is conjugated to the acidity-triggered rational membrane (ATRAM) peptide, which promotes specific and efficient internalization into malignant cells in the mildly acidic microenvironment of tumors. The nanospheres facilitated tumor magnetic resonance and thermal and fluorescence imaging and exhibited potent NIR laser light-induced anticancer effects in vitro and in vivo via combined ROS production and localized hyperthermia, with negligible toxicity to healthy tissue, hence markedly extending survival. Our results demonstrate that the ATRAM-functionalized, lipid/PEG-coated upconversion mesoporous silica nanospheres (ALUMSNs) offer multimodal diagnostic imaging and targeted combinatorial cancer therapy.

Integration of Activation by Hypoxia and Inhibition Resistance of Tumor Cells to Apoptosis for Precise and Augmented Photodynamic Therapy

Photodynamic therapy (PDT) uses photosensitizers to convert oxygen (O2 ) to reactive oxygen species (ROS) under irradiation to induce DNA damage and kill cancer cells. However, the effect of PDT is usually alleviated by apoptosis resistance mechanism of tumor living cells. MTH1 enzyme is known to be such an apoptosis-resistance enzyme which is over expressed as a scavenger to repair the damaged DNA. In this work, a hypoxia-activated nanosystem FTPA, which can be degraded to release the encapsulated PDT photosensitizer 4-DCF-MPYM and an inhibitor TH588 is proposed. The inhibitor TH588 can inhibit the DNA repair process by reducing the activity of MTH1 enzyme, and achieve the purpose of amplifying the therapeutic effect of PDT. This work demonstrates that a precise and augmented tumor PDT is achieved by integration of hypoxia-activation and inhibition resistance of tumor cells to apoptosis.

Research progress and application of the CRISPR/Cas9 gene-editing technology based on hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is now a common cause of cancer death, with no obvious change in patient survival over the past few years. Although the traditional therapeutic modalities for HCC patients mainly involved in surgery, chemotherapy, and radiotherapy, which have achieved admirable achievements, challenges are still existed, such as drug resistance and toxicity. The emerging gene therapy of clustered regularly interspaced short palindromic repeat/CRISPR-associated nuclease 9-based (CRISPR/Cas9), as an alternative to traditional treatment methods, has attracted considerable attention for eradicating resistant malignant tumors and regulating multiple crucial events of target gene-editing. Recently, advances in CRISPR/Cas9-based anti-drugs are presented at the intersection of science, such as chemistry, materials science, tumor biology, and genetics. In this review, the principle as well as statues of CRISPR/Cas9 technique were introduced first to show its feasibility. Additionally, the emphasis was placed on the applications of CRISPR/Cas9 technology in therapeutic HCC. Further, a broad overview of non-viral delivery systems for the CRISPR/Cas9-based anti-drugs in HCC treatment was summarized to delineate their design, action mechanisms, and anticancer applications. Finally, the limitations and prospects of current studies were also discussed, and we hope to provide comprehensively theoretical basis for the designing of anti-drugs.

Coupling Probiotics with 2D CoCuMo-LDH Nanosheets as a Tumor-Microenvironment-Responsive Platform for Precise NIR-II Photodynamic Therapy

Photodynamic therapy (PDT) has become a promising cancer treatment approach with superior advantages. However, it remains a grand challenge to develop tumor microenvironment (TME)-responsive photosensitizers (PSs) for tumor-targeting precise PDT. Herein, the coupling Lactobacillus acidophilus (LA) probiotics with 2D CoCuMo layered-double-hydroxide (LDH) nanosheets (LA&LDH) is reported as a TME-responsive platform for precise NIR-II PDT. The CoCuMo-LDH nanosheets loaded on LA can be transformed from crystalline into amorphous through etching by the LA-metabolite-enabled low pH and overexpressed glutathione. The TME-induced in situ amorphization of CoCuMo-LDH nanosheets can boost its photodynamic activity for singlet oxygen (¹ O₂ ) generation under 1270 nm laser irradiation with relative ¹ O₂ quantum yield of 1.06, which is the highest among previously reported NIR-excited PSs. In vitro and in vivo assays prove that the LA&LDH can effectively achieve complete cell apoptosis and tumor eradication under 1270 nm laser irradiation. This study proves that the probiotics can be used as a tumor-targeting platform for highly efficient precise NIR-II PDT.

Interactions of Nanomaterials with Gut Microbiota and Their Applications in Cancer Therapy

Cancer treatment is a challenge by its incredible complexity. As a key driver and player of cancer, gut microbiota influences the efficacy of cancer treatment. Modalities to manipulate gut microbiota have been reported to enhance antitumor efficacy in some cases. Nanomaterials (NMs) have been comprehensively applied in cancer diagnosis, imaging, and theranostics due to their unique and excellent properties, and their effectiveness is also influenced by gut microbiota. Nanotechnology is capable of targeting and manipulating gut microbiota, which offers massive opportunities to potentiate cancer treatment. Given the complexity of gut microbiota-host interactions, understanding NMs-gut interactions and NMs-gut microbiota interactions are important for applying nanotechnologies towards manipulating gut microbiota in cancer prevention and treatment. In this review, we provide an overview of NMs-gut interactions and NMs-gut microbiota interactions and highlight the influences of gut microbiota on the diagnosis and treatment effects of NMs, further illustrating the potential of nanotechnologies in cancer therapy. Investigation of the influences of NMs on cancer from the perspective of gut microbiota will boost the prospect of nanotechnology intervention of gut microbiota for cancer therapy.

Reversal of hepatic fibrosis by the co-delivery of drug and ribonucleoprotein-based genome editor

Liver fibrosis is a chronic disease without effective treatment in the clinic. Gene editing systems such as the well-known CRISPR/Cas9 have shown great potential in the biomedical field. However, the delivery of the ribonucleoprotein is challenging due to the unstable RNA probe and the requirement for the entrance to the nucleus. Recently, a structure-guided endonuclease (SGN) has been reported as an effective gene-editing system composed of a nuclease and stable DNA probes, which can regulate the protein expression by targeting specific mRNA outside the nucleus. Here, we conjugated the SGN to a nanomicelle as the delivery system. In the resulting material, the chance of the collision between the endonuclease and the probe was raised due to the confinement of the two components within the 40-nm nanomicelle, thus the mRNA can be cleaved immediately after being captured by the probe, resulting in a space-induced nucleotide identification-cleavage acceleration effect. The delivery system was used to treat liver fibrosis via the co-delivery of SGN and a drug rosiglitazone to the hepatic stellate cells, which separately downregulated the expression of tissue inhibitor of metalloprotease-1 and inactivated the hepatic stellate cells. The system successfully reversed the liver fibrosis in mice through the bidirectional regulatory that simultaneously promoted the degradation and inhibited the production of the collagen, demonstrating the great potency of the SGN system as gene medicine.

Silica Cross-Linked Micelle-Based Theranostic System for the Imaging and Treatment of Acute and Chronic Kidney Injury

Acute kidney injury (AKI) is a common and serious disease with high mortality and morbidity, and the persistent inflammatory environment brought about by AKI promotes its deterioration into chronic kidney disease (CKD). An efficient and timely targeted drug delivery to the renal tubules is crucial for AKI treatment. Here, we prepared silica cross-linked micelles (SCLMs) with different sizes and studied their targeting ability to the injured kidney. It is found that the SCLMs with a size of 13 nm could rapidly accumulate and remain in the damaged kidney. Immunofluorescence results confirmed that SCLMs are selectively located in the damaged tubular cells but cannot be found in healthy renal tissue. Therefore, fluorescent dye-labeled SCLMs were used for the imaging of the injured kidney, which could reflect the status of the kidney injury. Furthermore, atorvastatin, an antioxidative and anti-inflammatory drug, was loaded in SCLMs as the therapeutic agents for the treatment of ischemia/reperfusion-induced AKI and CKD. Renal function indexes, such as tubular necrosis, collagen deposition, and inflammation, were effectively improved after the treatment.

Targeting Warburg effect to rescue the suffocated photodynamic therapy: A cancer-specific solution

The cancer photodynamic therapy (PDT) is limited by a congenital defect, namely the tumor hypoxia. Cancer cells are characterized by the vigorous oxygen-consuming glycolysis, which is well-known as the "Warburg effect" and one of the primary causes for the hypoxia. Herein, we employed the glucose metabolism as the cancer-specific target to enhance the performance of PDT. The Salvianolic acid B as the inhibitor of glucose uptake and aerobic glycolysis was concomitantly delivered with the photosensitizer chlorin e6 by a redox-responsive organosilica cross-linked micelle. The results demonstrated that the Salvianolic acid B suppressed the glucose metabolism, retarded the oxygen consumption to retain adequate oxygen as the ammo for PDT, which remarkably improve the efficacy of PDT both in vitro and in vivo. Our study not only provides an alternative strategy to address the hypoxia problem for PDT, but also enhances the selectivity of the treatment by targeting the cancer-specific Warburg effect.

Ultrasound-Amplified Enzyodynamic Tumor Therapy by Perovskite Nanoenzyme-Enabled Cell Pyroptosis and Cascade Catalysis

Overcoming apoptosis resistance to achieve efficient breast cancer treatment remains a challenge. The precise induction of another form of programmed cell death, pyroptosis, is an excellent alternative for treating cancer. Ultrasound (US)-enhanced enzyme dynamic (enzyodynamic) therapy is developed by employing LaFeO₃ (LFO) perovskite nanocrystals as a substrate to increase the rate of deleterious reactive oxygen species (ROS) generation for intensive cell pyroptosis. LFO nanocrystals possess quadruple enzyme-mimicking activities, including oxidase-, peroxidase-, glutathione peroxidase-, and catalase-mimicking activities, which undertake the dominant therapeutic task through cascade catalytic reactions, including the reversal of hypoxic microenvironment, depletion of endogenous glutathione, and continuous output of ROS. US exogenous stimulation increases the transition rate of the intermediate complex to Fe (II) and favors incremental ROS production, by which the ROS burst-induced pyroptosis process is accomplished through the ROS-TXNIP-NLRP3-GSDMD pathway. Both in vitro and in vivo antineoplastic outcomes affirm the ascendancy of LFO nanozyme-induced pyroptosis. This work highlights the critical role of US coupled with nanocatalytic reactors in pyroptosis-dominant breast cancer treatment with the apoptosis resistance circumvention feature.

A novel 450-nm laser-mediated sinoporphyrin sodium-based photodynamic therapy induces autophagic cell death in gastric cancer through regulation of the ROS/PI3K/Akt/mTOR signaling pathway

BACKGROUND

Photodynamic therapy (PDT) has become an ideal and promising therapeutic method for fighting cancer, but its common application in clinical practice is prevented by the limitations of expensive devices in light sources and phototoxicity in photosensitizers. The aim of this study was to explore the antitumor efficiency of the novel 450-nm blue laser (BL) combined with sinoporphyrin sodium (DVDMS)-mediated PDT against human gastric cancer (GC) in vitro and in vivo, focusing on autophagy pathway.

METHODS

Cell viability was detected by Cell Counting Kit-8 and colony formation assays in HGC27, MGC803, AGS, and GES-1 cells. Cell apoptosis was measured by flow cytometry and western blotting. The production of reactive oxygen species (ROS) was measured by fluorescence microscopy and flow cytometry. Autophagy was determined by transmission electron microscopy and western blotting. The antitumor effect of BL-PDT in vivo was detected by a subcutaneous tumor model in nude mice.

RESULTS

The novel 450-nm laser-mediated DVDMS-based PDT caused remarkable growth inhibition and apoptosis induction in GC cells in vitro by the production of excessive ROS. Autophagy flux was induced by BL-PDT in GC cells, as determined by LC3 conversion assay, LC3 turnover assay, and mRFP-GFP-LC3 puncta assay. Furthermore, autophagy induction was demonstrated to positively contribute to BL-PDT-induced apoptotic effects on GC cells. Mechanically, ROS/PI3K/Akt/mTOR pathway was identified to involve in the regulation of BL-PDT-induced autophagy as determined by transcriptomic analysis and functional studies. Consistently, xenograft studies confirmed the significant antitumor effect of BL-PDT and its favorable safety in vivo.

CONCLUSIONS

The novel 450-nm laser-mediated DVDMS-based PDT may be a safe and effective approach against GC. Our results thus provide compelling evidence for the therapeutic application of BL-PDT in human GC.

A MCL-1-targeted photosensitizer to combat triple-negative breast cancer with enhanced photodynamic efficacy, sensitization to ROS-induced damage, and immune response

As growth factor receptor-2 (HER-2), progesterone receptor (PR) and estrogen receptor (ER) are scarce in triple-negative breast cancer (TNBC), it is a great challenge to combat TNBC with high tumor specificity and therapeutic efficacy. Most traditional treatments including surgical resection, chemotherapy, and radiotherapy would more or less cause serious side effects and drug resistance. Photodynamic therapy (PDT) has huge potential in the treatment of TNBC for minimal invasiveness, low toxicity, less drug resistance and high spatiotemporal selectivity. Inspired by the advantages of small-molecule-targeted PDT and the sensitization effect of myeloid cell leukemia-1 (MCL-1) inhibitor, a novel photosensitizer BC-Pc was designed by conjugating MCL-1 inhibitor with zinc phthalocyanines. Owning to 3-chloro-6-methyl-1-benzothiophene-2-carboxylic acid (BC) moiety, BC-Pc exhibits the high affinity towards MCL-1 and reduce its self-aggregation in TNBC cells. Therefore, MCL-1 targeted BC-Pc showed remarkable intracellular fluorescence and ROS generation in TNBC cells. Additionally, BC-Pc can selectively sensitize TNBC cells to ROS-induced damage, resulting in improved therapeutic effect to TNBC cells and negligible toxicity to normal cells. More importantly, BC-Pc can effectively inhibit the migration and invasion of TNBC cells, and enhance immune response, all of which will be beneficial to eradicate TNBC. To the best of our knowledge, BC-Pc is the novel MCL-targeted photosensitizer, which owns the amplified ROS-induced lethality and anticancer immune response for TNBC. Overall, our study provides a promising strategy to achieve targeting and highly efficient therapy of TNBC.

The Role of 8-oxoG Repair Systems in Tumorigenesis and Cancer Therapy

Tumorigenesis is highly correlated with the accumulation of mutations. The abundant and extensive DNA oxidation product, 8-Oxoguanine (8-oxoG), can cause mutations if it is not repaired by 8-oxoG repair systems. Therefore, the accumulation of 8-oxoG plays an essential role in tumorigenesis. To avoid the accumulation of 8-oxoG in the genome, base excision repair (BER), initiated by 8-oxoguanine DNA glycosylase1 (OGG1), is responsible for the removal of genomic 8-oxoG. It has been proven that 8-oxoG levels are significantly elevated in cancer cells compared with cells of normal tissues, and the induction of DNA damage by some antitumor drugs involves direct or indirect interference with BER, especially through inducing the production and accumulation of reactive oxygen species (ROS), which can lead to tumor cell death. In addition, the absence of the core components of BER can result in embryonic or early post-natal lethality in mice. Therefore, targeting 8-oxoG repair systems with inhibitors is a promising avenue for tumor therapy. In this study, we summarize the impact of 8-oxoG accumulation on tumorigenesis and the current status of cancer therapy approaches exploiting 8-oxoG repair enzyme targeting, as well as possible synergistic lethality strategies involving exogenous ROS-inducing agents.

Upconversion Nanoparticle-Based Cell Membrane-Coated cRGD Peptide Bioorthogonally Labeled Nanoplatform for Glioblastoma Treatment

Glioblastoma is hard to be eradicated partly because of the obstructive blood-brain barrier (BBB) and the dynamic autophagy activities of glioblastoma. Here, hydroxychloroquine (HDX)-loaded yolk-shell upconversion nanoparticle (UCNP)@Zn0.5Cd0.5S nanoparticle coating with the cyclic Arg-Gly-Asp (cRGD)-grafted glioblastoma cell membrane for near-infrared (NIR)-triggered treatment of glioblastoma is prepared for the first time. UCNPs@Zn0.5Cd0.5S (abbreviated as YSN, yolk-shell nanoparticle) under NIR radiation will generate reactive oxygen species for imposing cytotoxicity. HDX, the only available autophagy inhibitor in clinical studies, can enhance cytotoxicity by preventing damaged organelles from being recycled. The cRGD-decorated cell membrane allowed the HDX-loaded nanoparticles to efficiently bypass the BBB and specifically target glioblastoma cells. Exceptional treatment efficacy of the NIR-triggered chemotherapy and photodynamic therapy was achieved in U87 cells and in the mouse glioblastoma model as well. Our results provided proof-of-concept evidence that HDX@YSN@CCM@cRGD could overcome the delivery barriers and achieve targeted treatment of glioblastoma.

A Multifunctional Non-viral Vector for the Delivery of MTH1-targeted CRISPR/Cas9 System for Non-Small Cell Lung Cancer Therapy

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system adapted from bacteria is a programmable nuclease-based genome editing tool. The long-lasting effect of gene silencing or correction is beneficial in cancer treatment. Considering the need to broaden the practical application of this technology, highly efficient non-viral vectors are urgently required. We prepared a multifunctional non-viral vector that could actively target tumor cells and deliver CRISPR/Cas9 plasmids into nuclei of cancer cells. Protamine sulfate (PS) which contains nuclear localization sequence was utilized to condense plasmid DNA and facilitate nuclei-targeted delivery. Liposome-coated protein/DNA complex avoided the degradation of nuclease in blood circulation. The obtained PS@Lip/pCas9 was further modified with distearoyl phosphoethanolamine-polyethylene glycol-hyaluronic acid (HA) to endow the vector ability to actively target tumor cell. Results suggested that PS@HA-Lip could deliver CRISPR/Cas9 plasmids into nuclei of tumor cells and induce genome editing effect. With the disruption of MTH1 (mutT homolog1) gene, the growth of non-small cell lung cancer was inhibited. Moreover, cell apoptosis in tumor tissue was promoted, and liver metastasis of non-small cell lung cancer (NSCLC) was reduced. Our study has provided a therapeutic strategy targeting MTH1 gene for NSCLC therapy. STATEMENT OF SIGNIFICANCE: CRISPR/Cas9 as a powerful tool for genome editing has drawn much attention. The long-lasting effect possesses unique advantage in cancer treatment. Non-viral vectors have high loading capacity, high safety and low immunogenicity, playing an important role in CRISPR/Cas9 delivery. In our study, a multifunctional non-viral vector for the efficient delivery of CRISPR/Cas9 plasmid was constructed. With the active targeting ligand and nuclei-targeting component, the cargo was efficiently delivered into cell nuclei and exerted genome editing effect. By using this vector, we successfully inhibited the growth and induced the apoptosis of non-small cell lung cancer by disrupting MTH1 expression with good safety. Our work provided an efficient non-vial vector for CRISPR/Cas9 delivery and explored the possibility for cancer treatment.

NIR/MRI-Guided Oxygen-Independent Carrier-Free Anti-Tumor Nano-Theranostics

Imaging-guided photothermal therapy (PTT)/photodynamic therapy (PDT) for cancer treatment are beneficial for precise localization of the malignant lesions and combination of multiple cell killing mechanisms in eradicating stubborn thermal-resistant cancer cells. However, overcoming the adverse impact of tumor hypoxia on PDT efficacy remains a challenge. Here, carrier-free nano-theranostic agents are developed (AIBME@IR780-APM NPs) for magnetic resonance imaging (MRI)-guided synergistic PTT/thermodynamic therapy (TDT). Two IR780 derivatives are synthesized as the subject of nanomedicine to confer the advantages for the nanomedicine, which are by feat of amphiphilic IR780-PEG to enhance the sterical stability and reduce the risk from reticuloendothelial system uptake, and IR780-ATU to chelate Mn²⁺ for T₁ -weighted MRI. Dimethyl 2,2'-azobis(2-methylpropionate) (AIBME), acting as thermally decomposable radical initiators, are further introduced into nanosystems with the purpose of generating highly cytotoxic alkyl radicals upon PTT launched by IR780 under 808 nm laser irradiation. Therefore, the sequentially generated heat and alkyl radicals synergistically induce cell death via synergistic PTT/TDT, ignoring tumor hypoxia. Moreover, these carrier-free nano-theranostic agents present satisfactory biocompatibility, which could be employed as a powerful weapon to hit hypoxic tumors via MRI-guided oxygen-independent PTT and photonic TDT.

Imaging moiety-directed co-assembly for biodegradation control with synchronous four-modal biotracking

The complexity of existing methods for biodegradation control limits the multi-functionality of biomedical materials. It is urgent to develop simple and straightforward strategies to control the biodegradation rate with precise tracking of various parameters in real-time. Here, we show an imaging moiety-directed co-assembly strategy, in which different imaging moieties bearing non-covalent interaction sites are covalently introduced into the poly (D,l-lactic acid) (PDLLA) chain as end groups, followed by alternate non-covalent interactions with polymer chains upon compression molding. This strategy takes advantage of a variety of bonding types (including CH-π, CH-F, etc.) to firmly integrate the PDLLA chains and strongly control the biodegradation rate, making the amorphous prototype degraded much slower than higher-molecular-weight counterparts, and the local inflammatory response is insignificant. On this basis, a synchronous four-modal (X-ray computed tomography + fluorescence + photoacoustics + ultrasound) imaging was achieved on the single entity in vivo, even within a millimeter-scale thick-skin tissue. These imaging signals can precisely correlate the multi parameter variation trend of material mass, volume and molecular weight, signifying that co-assembly can be utilized to develop advanced theranostic systems. SINGLE SENTENCE SUMMARY: We developed an imaging moiety-directed co-assembly strategy to control the biodegradation rate and achieve the synchronization of real-time four-modal imaging in vivo. These imaging signals can precisely correlate the multi-parameter variation trend of material mass, volume and molecular weight, which provided comprehensive biomedical information accessing both qualitatively and quantitatively.

Co-delivery of photosensitizer and diclofenac through sequentially responsive bilirubin nanocarriers for combating hypoxic tumors

Considering that photodynamic therapy (PDT)-induced oxygen consumption and microvascular damage could exacerbate hypoxia to drive more glycolysis and angiogenesis, a novel approach to potentiate PDT and overcome the resistances of hypoxia is avidly needed. Herein, morpholine-modified PEGylated bilirubin was proposed to co-deliver chlorin e6, a photosensitizer, and diclofenac (Dc). In acidic milieu, the presence of morpholine could enable the nanocarriers to selectively accumulate in tumor cells, while PDT-generated reactive oxidative species (ROS) resulted in the collapse of bilirubin nanoparticles and rapid release of Dc. Combining with Dc showed a higher rate of apoptosis over PDT alone and simultaneously triggered a domino effect, including blocking the activity and expression of lactate dehydrogenase A (LDHA), interfering with lactate secretion, suppressing the activation of various angiogenic factors and thus obviating hypoxia-induced resistance-glycolysis and angiogenesis. In addition, inhibition of hypoxia-inducible factor-1α (HIF-1α) by Dc alleviated hypoxia-induced resistance. This study offered a sequentially responsive platform to achieve sufficient tumor enrichment, on-demand drug release and superior anti-tumor outcomes in vitro and in vivo.

Magnetically Boosted Generation of Intracellular Reactive Oxygen Species toward Magneto-Photodynamic Therapy

The generation of reactive oxygen species (ROS) in photodynamic therapy (PDT) involves excited-state intermediates with both singlet and triplet spin configurations, which provides possibilities to modulate the ROS production in PDT under an external magnetic field. Here, we present that magnetically modulated ROS production can promote PDT efficacy and develop a magnetic-field-assisted PDT (magneto-PDT) method for effectively and selectively killing cancer cells. The photosensitization reaction between excited-state riboflavin and oxygen molecules is influenced by the applied field, and the overall magnetic field effect (MFE) shows a moderate increase at a low field (<1000 G) and then a boost up to the saturation ∼100% at a high field (>1000 G). It is found that the spin precession occurring in radical ion pairs (electron transfer from riboflavin to oxygen) facilitates the O₂^•- generation at the low field. In comparison, the spin splitting in an encounter complex (energy transfer from riboflavin to oxygen) benefits the production of ¹O₂ species at the high field. The field modulation on the two types of ROS in PDT, i.e., O₂^•- and ¹O₂, is also demonstrated in living cells. The magneto-PDT strategy shows the capability to inhibit the proliferation of cancer cells (e.g., HeLa, RBL-2H3, and MCF-7) effectively and selectively, which reveals the potential of using the MFE on chemical reactions in biological applications.

Self-Delivery Nanomedicine for Glutamine-Starvation Enhanced Photodynamic Tumor Therapy

Glutamine metabolism of tumor cells plays a crucial role in maintaining cell homeostasis and reducing oxidative damage. Herein, a valid strategy of inhibiting glutamine metabolism is proposed to amplify the oxidative damage of photodynamic therapy (PDT) to tumor cells. Specifically, the authors develop a drug co-delivery system (designated as CeV) based on chlorine e6 (Ce6) and V9302 via the self-assembly technology. In spite of the strong hydrophobicity of therapeutic agents, the assembled CeV holds a favorable dispersibility in water and an improved cellular uptake capability. Under light irradiation, the internalized CeV is capable of generating abundant reactive oxygen species (ROS) for PDT. More importantly, CeV can reduce the uptake of glutamine through V9302-mediated alanine-serine-cysteine transporter of type-2 (ASCT2) inhibition, leading to a reduced glutathione (GSH) production and an amplified oxidative stress. As a result, CeV has a robust PDT efficacy on tumor inhibition by the blockade of glutamine transport. Notably, CeV exhibits a superiority on tumor suppression over the single treatment as well as the combined administration of Ce6 and V9302, which indicates the advantage of CeV for synergistic treatment. It may serve as a novel nanoplatform for developing a drug co-delivery system to improve PDT efficiency by inhibiting cell metabolism.

Carrier Free Photodynamic Synergists for Oxidative Damage Amplified Tumor Therapy

Tumor cells adapt to excessive oxidative stress by actuating reactive oxygen species (ROS)-defensing system, leading to a resistance to oxidation therapy. In this work, self-delivery photodynamic synergists (designated as PhotoSyn) are developed for oxidative damage amplified tumor therapy. Specifically, PhotoSyn are fabricated by the self-assembly of chlorine e6 (Ce6) and TH588 through π-π stacking and hydrophobic interactions. Without additional carriers, nanoscale PhotoSyn possess an extremely high drug loading rate (up to 100%) and they are found to be fairly stable in aqueous phase with a uniform size distribution. Intravenously injected PhotoSyn prefer to accumulate at tumor sites for effective cellular uptake. More importantly, TH588-mediated MTH1 inhibition could destroy the ROS-defensing system of tumor cells by preventing the elimination of 8-oxo-2'-deoxyguanosine triphosphate (8-oxo-dG), thereby exacerbating the oxidative DNA damage induced by the photodynamic therapy (PDT) of Ce6 under light irradiation. As a consequence, PhotoSyn exhibit enhanced photo toxicity and a significant antitumor effect. This amplified oxidative damage strategy improves the PDT efficiency with a reduced side effect by increasing the lethality of ROS without generating superabundant ROS, which would provide a new insight for developing self-delivery nanoplatforms in photodynamic tumor therapy in clinic.

Oxygen-Independent Photocleavage of Radical Nanogenerator for Near-IR-Gated and H2 O-Mediated Free-Radical Nanotherapy

The oxygen-dependent nature and limited penetration capacity of visible light render the low efficiency of photodynamic therapy in hypoxic and deep-seated tumors. Therefore, the development of oxygen-free photoactivated chemotherapy (PACT) to generate cytotoxic reactive oxygen species by near-IR (NIR) light-cleavable photocages is in high demand. Here, an oxygen-irrelevant PACT strategy based on NIR light-triggered hydroxyl radicals (•OH) generation is developed for free-radical nanotherapy. Blebbistatin-loaded upconversion of mesoporous silica nanoparticles (UCSNs-B) is established to facilitate the high loading efficiency of blebbistatin and implement the efficient transformation of NIR light into blue light for unprecedented direct photorelease of oxygen-independent •OH. Under NIR laser irradiation, UCSNs-B converted NIR light into blue light, thus enabling the photocleavage of blebbistatin to induce the burst of •OH. The •OH burst under NIR laser irradiation further induces cancer cell apoptosis and significant suppression of hypoxic tumors. In addition, the gadolinium ion (Gd³⁺ )-doped UCSNs-B are used as contrast agents in magnetic resonance imaging to facilitate real-time monitoring of the therapeutic processes. This study effectively demonstrates that the UCSNs-B act as NIR light-triggered photocages to facilitate oxygen-irrelevant •OH bursts, thus providing insights into the development of efficient PACT nanoagents for cancer treatment.

An Approach to Developing Cyanines with Simultaneous Intersystem Crossing Enhancement and Excited-State Lifetime Elongation for Photodynamic Antitumor Metastasis

Heavy-atom-based photosensitizers usually exhibit shortened triplet-state lifetimes, which is not ideal for hypoxic tumor photodynamic therapy. Although several heavy-atom-free photosensitizers possess long triplet-state lifetimes, the clinical applicability is limited by their short excitation wavelengths, poor photon capture abilities, and intrinsically hydrophobic structures. Herein we developed a novel NIR heavy-atom-free photosensitizer design strategy by introducing sterically bulky and electron-rich moieties at the meso position of the pentamethine cyanine (Cy5) skeleton, which simultaneously enhanced intersystem crossing (ISC) and prolonged excited-state lifetime. We found that the ¹O₂ generation ability is directly correlated to the electron-donating ability of the meso substituent in cyanine, and the excited-state lifetime was simultaneously much elongated when the substituents were anthracene derivatives substituted at the 9-position. Our star compound, ANOMe-Cy5, exhibits intense NIR absorption, the highest ¹O₂ quantum yield (4.48-fold higher than Cy5), the longest triplet-state lifetime (9.80-fold longer than Cy5), and lossless emission intensity (nearly no change compared with Cy5). Such excellent photophysical properties coupled with its inherently cationic and hydrophilic nature enable the photosensitizer to realize photoablation of solid tumor and antitumor lung metastasis. This study highlights the design of a new generation of NIR photosensitizers for imaging-guided photodynamic cancer treatment.

Nanoengineering of a newly designed chlorin e6 derivative for amplified photodynamic therapy via regulating lactate metabolism

Chlorin e6 (Ce6) is a widely utilized photosensitizer in photodynamic therapy (PDT) against tumor growth, but its hydrophobic feature and the hypoxia in the tumor microenvironment greatly compromise its therapeutic efficacy. To address the issues, here we designed a new Ce6 derivative (TCe6) by coupling Ce6 with amphiphilic d-α-tocopherol polyethylene glycol 1000 succinate (TPGS), endowing Ce6 with an excellent amphiphilic feature. In particular, the overall reactive oxygen species (ROS) generation by TCe6 was significantly enhanced because TPGS could interact with mitochondrial complex II to induce extra ROS production, amplifying the total ROS production under PDT. Inspired by the unique property of α-cyano-4-hydroxycinnamate (CHC) in regulating lactate metabolism to spare more intracellular oxygen for PDT, TCe6 was further co-assembled with CHC to construct TCe6/CHC nanoparticles (NPs) for addressing the insufficient oxygen issue in PDT. The as-prepared TCe6/CHC NPs not only increased the efficiency of cell internalization but also improved the solubility and stability of Ce6 and CHC. Thanks to the extra ROS production by the TPGS unit, the amphiphilic feature of TCe6 and the CHC-mediated hypoxia microenvironment, the TCe6/CHC NPs demonstrated excellent PDT against tumor growth. This work provided a versatile strategy to solve the current bottleneck in photosensitizer-based PDT, holding great promise for the design of advanced photodynamic nanoplatforms.

Inhibition of the NRF2/KEAP1 Axis: A Promising Therapeutic Strategy to Alter Redox Balance of Cancer Cells

Significance: The nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (NRF2/KEAP1) pathway is a crucial and highly conserved defensive system that is required to maintain or restore the intracellular homeostasis in response to oxidative, electrophilic, and other types of stress conditions. The tight control of NRF2 function is maintained by a complex network of biological interactions between positive and negative regulators that ultimately ensure context-specific activation, culminating in the NRF2-driven transcription of cytoprotective genes. Recent Advances: Recent studies indicate that deregulated NRF2 activation is a frequent event in malignant tumors, wherein it is associated with metabolic reprogramming, increased antioxidant capacity, chemoresistance, and poor clinical outcome. On the other hand, the growing interest in the modulation of the cancer cells' redox balance identified NRF2 as an ideal therapeutic target. Critical Issues: For this reason, many efforts have been made to identify potent and selective NRF2 inhibitors that might be used as single agents or adjuvants of anticancer drugs with redox disrupting properties. Despite the lack of specific NRF2 inhibitors still represents a major clinical hurdle, the researchers have exploited alternative strategies to disrupt NRF2 signaling at different levels of its biological activation. Future Directions: Given its dualistic role in tumor initiation and progression, the identification of the appropriate biological context of NRF2 activation and the specific clinicopathological features of patients cohorts wherein its inactivation is expected to have clinical benefits, will represent a major goal in the field of cancer research. In this review, we will briefly describe the structure and function of the NRF2/ KEAP1 system and some of the most promising NRF2 inhibitors, with a particular emphasis on natural compounds and drug repurposing. Antioxid. Redox Signal. 34, 1428-1483.

Recent near-infrared light-activated nanomedicine toward precision cancer therapy

Light has been present throughout the history of mankind and even the universe. It is of great significance to human life, contributing to energy, agriculture, communication, and much more. In the biomedical field, light has been developed as a switch to control medical processes with minimal invasion and high spatiotemporal selectivity. During the past three years, near-infrared (NIR) light as long-wavelength light has been applied to more than 3000 achievements in biological applications due to its deep penetration depth and low phototoxicity. Remotely controlled cancer therapy usually involves the conversion of biologically inert NIR light. Thus, various materials, especially nanomaterials that can generate reactive oxygen species (ROS), ultraviolet (UV)/visual light, or thermal energy and so on under NIR illumination achieve great potential for the research of nanomedicine. Here, we offered an overview of recent advances in NIR light-activated nanomedicine for cancer therapeutic applications. NIR-light-conversion nanotechnologies for both directly triggering nanodrugs and smart drug delivery toward tumor therapy were discussed emphatically. The challenges and future trends of the use of NIR light in biomedical applications were also provided as a conclusion. We expect that this review will spark inspiration for biologists, materials scientists, pharmacologists, and chemists to fight against diseases and boost the future clinical-translational applications of NIR technology-based precision nanomedicine.

A cyclic nano-reactor achieving enhanced photodynamic tumor therapy by reversing multiple resistances

BACKGROUND

Photodynamic therapy (PDT) is a clinically implemented modality to combat malignant tumor, while its efficacy is largely limited by several resistance factors from tumor microenvironment (TME), such as hypoxia, anti-oxidant systems, and ATP-dependent tumor adaptive resistances. The aim of this work is to construct a multifunctional nanoplatform to remodel multiple resistant TME for enhanced PDT.

RESULTS

Here, a targeting nano-reactor was facilely constructed to reverse the multiple resistances of PDT by incorporating glucose oxidase (GOx) and chlorin e6 (Ce6) into poly (D, L-lactic-co-glycolic acid) (PLGA)/ metal-organic framework (MOF) core-shell nanoassembly, with surface deposition of hyaluronic acid (HA) stabilized MnO2. The nano-reactor could selectively target tumor cells by virtue of surface HA modification, and once internalization, a few reactions were initiated to modulate TME. Glucose was consumed by GOx to inhibit ATP generation, and the produced H2O2 was catalyzed by MnO2 to generate O2 for tumor hypoxia alleviation and photodynamic sensitization, and glutathione (GSH) was also effectively depleted by MnO2 to suppress the tumor antioxidant defense. Consequently, the nano-reactor achieved robust PDT with amplified tumor therapy via intravenous injection.

CONCLUSIONS

This nano-reactor offers a multifunctional nanoplatform to sensitize TME-limited tumor treatment means via reversing multiple resistances.

1550 nm excitation-responsive upconversion nanoparticles to establish dual-photodynamic therapy against pancreatic tumors

The second near-infrared biological window b (NIR-IIb, 1500-1700 nm) is recently considered as the promising region for deeper tissue penetration. Herein, a nanocarrier for 1550 nm light-responsive dual-photodynamic therapy (PDT) is developed to efficiently boost singlet oxygen (1O2) generation. The dual-photosensitizers (PSs), rose bengal (RB) and chlorin e6 (Ce6), are carried by the silica-coated core-shell LiYbF4:Er@LiGdF4 upconversion nanoparticles (UCNPs), forming UCNP/RB,Ce6. Following 1550 nm laser irradiation, the upconversion emission of UCNP/RB,Ce6 in both green (∼550 nm) and red (∼670 nm) colors is fully utilized to activate RB and Ce6, respectively. The simultaneous triggering of dual-PS generates an abundant amount of 1O2 resulting in boosted PDT efficacy. This dual-PDT nanocarrier presents an enhanced anticancer effect under single dose treatment in comparison with the single-PS ones from in vitro and in vivo treatments. The marriage between the boosted dual-PDT and 1550 nm light excitation is anticipated to provide a new avenue for non-invasive therapy.

Phototherapy and anti-GITR antibody-based therapy synergistically reinvigorate immunogenic cell death and reject established cancers

Phototherapy and immunogenic cell death (ICD) are powerful strategies to fight cancer. However, their therapeutic outcomes are diminished by immunosuppressive and hypoxia microenvironment. Herein, a photo-based, immunomodulating and hypoxia-alleviated nanosystem, PDA-ICG@CAT-DTA-1, is proposed to achieve the synergism between phototherapy and immunotherapy. Catalase (CAT) and anti-GITR antibody (DTA-1) are loaded to photothermal agent and photosensitizer composed PDA-ICG nanoparticles. The PDA-ICG@CAT-DTA-1 exhibits intrinsic local hyperthermia and enhanced ROS generation in tumor, and abrogates tumor immune suppression. It results in reduction of intratumoral FOXP3⁺ regulatory T cells (4.3-fold) and increase of CD4⁺ effector T cells (1.5-fold) compare with the control, and promotes damage associated molecular patterns generation to reinvigorate ICD effect. The potent antitumor of PDA-ICG@CAT-DTA-1 is proved in 4T1 bilateral tumor-bearing mice, with inhibition ratio of 95.1% for primary cancers and 68.7% for abscopal cancers. Our findings highlight great promise of the constructed versatility nanosystem to fix bottlenecks for cancer therapy.

Enhancement of tumor lethality of ROS in photodynamic therapy

In the process of photodynamic therapy (PDT) treatment of tumors, reactive oxygen species (ROS) plays a key role in destroying tumor tissues. However, traditional PDT often has limited ROS killing capacity due to hypoxia in the tumor microenvironment (TME) or obstruction by the ROS defense system, resulting in poor efficacy. Therefore, enhancing the killing effect of ROS on tumors is the core of enhancing the anti-tumor effect of PDT. In recent years, many studies have developed a series of strategies to enhance the ability of ROS to kill tumors in view of the limitations of the TME on PDT. This article summarizes the commonly used or innovative strategies in recent years, including not only frequently used methods for hypoxia in the TME but also innovative strategies to inhibit the ROS defense system.