As a promising gene therapy strategy, controllable small molecule-mRNA covalent modification in tumor cells could be initiated by singlet oxygen (1O2) to complete the modification process. However, in vivo generation of 1O2 is usually dependent on excitation of external light, and the limited light penetration of tissues greatly interferes the development of deep tumor phototherapy. Here, we constructed a tumor-targeting nano-micelle for the spontaneous intracellular generation of 1O2 without the need for external light, and inducing a high level of covalent modification of mRNA in tumor cells. Luminal and Ce6 were chemically bonded to produce 1O2 by chemiluminescence resonance energy transfer (CRET) triggered by high levels of hydrogen peroxide (H2O2) in the tumor microenvironment. The sufficient 1O2 oxidized the loaded furan to highly reactive dicarbonyl moiety, which underwent cycloaddition reaction with adenine (A), cytosine (C) or guanine (G) on the mRNA for interfering with the tumor cell protein expression, thereby inhibiting tumor progression. In vitro and in vivo experiments demonstrated that this self-initiated gene therapy nano-micelle could induce covalent modification of mRNA by 1O2 without external light, and the process could be monitored in real time by fluorescence imaging, which provided an effective strategy for RNA-based tumor gene therapy.

Carrier-free nanodrugs are a novel type of drug constructed by the self-assembly of drug molecules without carrier involvement. They have the characteristics of small particle size, easy penetration of various barriers, targeting tumors, and efficient release. In recent years, carrier-free nanodrugs have become a hot topic in tumor therapy as they solve the problems of low drug loading, poor biocompatibility, and low uptake efficiency of carrier nanodrugs. A series of recent studies have shown that carrier-free nanodrugs play a vital role in the treatment of various tumors, with similar or better effects than carrier nanodrugs. Based on the literature published in the past decades, this paper first summarizes the recent progress in the assembly modes of carrier-free nanodrugs, then describes common therapeutic modalities of carrier-free nanodrugs in tumor therapy, and finally depicts the existing challenges along with future trends of carrier-free nanodrugs. We hope that this review can guide the design and application of carrier-free nanodrugs in the future.

Mass transfer of bulky molecules, e.g., bioenzymes, particularly for cross-scale multibiomolecules, imposes serious challenges for microporous metal-organic frameworks (MOFs). Here, we create a hierarchically porous MOF heterostructure featuring highly region-ordered micro-, meso-, and macro-pores by growing a microporous ZIF-8 shell onto a hollow Prussian blue core through an epitaxial growth strategy. This allows for localized loading of large bioenzyme glucose oxidase (GOx) and small drug 5-fluorouracil (5-FU) within specific pores simultaneously and triggers unique guest-carrier cooperative anticancer capabilities. The stable ZIF-8 outer layer effectively blocks the core pores, preventing the undesired leakage of GOx into normal tissues. The acidity-induced ZIF-8 degradation gradually releases Zn2+ and loaded 5-FU for chemotherapy under acidic tumor microenvironments. With the loss of the shielding effect of the ZIF-8 coating, the released GOx depletes intratumoral glucose (Glu) for starvation therapy. Notably, an accelerated cascade reaction occurs between ZIF-8 decomposition and GOx release, facilitated by the modulator factor of Glu. This culminates in the realization of synergistic cancer therapy, as comprehensively demonstrated by in vitro and in vivo experiments, as well as transcriptome sequencing analyses. Our work not only introduces a hierarchically porous MOF heterostructure with highly region-ordered pores but also provides a perspective for guest-carrier cooperative anticancer therapy.

Introduction: The tumor microenvironment and multidrug resistance of tumor cells seriously impair the activity of the nanozymes. Methods: Herein, a polyethylene glycol (PEG)-modified vanadium-doped molybdenum disulfide (V-MoS2@PEG) nanozymes were constructed to enhance anti-tumor activity through multi-enzymatic catalysis and photothermal effect with simultaneous reactive oxygen species replenishment and glutathione depletion. Results and discussion: V-MoS2@PEG nanosheets exerted peroxidase activity by causing molybdenum ion (Mo4+) to react with hydrogen peroxide to form toxic hydroxyl radicals (·OH). Meanwhile, the V-doping can deplete glutathione avoiding ·OH consumption. In addition, the high heat generated by V-MoS2@PEG nanozymes under near-infrared laser irradiation brought about a desirable local temperature gradient, which produced an enhanced catalytic effect by promoting band bending. Furthermore, the photothermally inspired polarized charge increased the permeability of the tumor cell membrane and promoted further aggregation of the nanozymes, which realized the combination of photothermal therapy with multi-enzymatic catalysis, solved the problem of multi-enzyme catalysis, and improved the anti-tumor efficiency.

Glioma is the most common malignant tumor in the brain, accounting for over 80% of all primary intracranial tumors. The current clinical treatment has shown certain limitations. Although M1 type microglia can secrete various pro-inflammatory cytokines and are expected to be used for glioma treatment, direct use of microglia may lead to overactivation and trigger immune storms. Therefore, we first found that serum starvation can stimulate the transformation of microglia into M1 type. Subsequently, we found through comparative experiments that the inhibitory effect of microglial cell lysis medium on glioma cells was stronger than that of microglial cell culture medium. Finally, we successfully prepared sodium alginate hydrogel loaded with microglia lysis solution to achieve sustained inhibitory effect on the growth of glioma and avoid its proliferation.

Engineered Salmonella has emerged as a promising microbial immunotherapy against tumors; however, its clinical effectiveness has encountered limitations. In our investigation, we unveil a non-dose-dependent type of behavior regarding Salmonella\'s therapeutic impact and reveal the regulatory role of neutrophils in diminishing the efficacy of this. While Salmonella colonization within tumors recruits a substantial neutrophil population, these neutrophils predominantly polarize into the pro-tumor N2 phenotype, elevating PD-L1 expression and fostering an immunosuppressive milieu within the tumor microenvironment. In order to bypass this challenge, we introduce MnO2 nanoparticles engineered to activate the STING pathway. Harnessing the STING pathway to stimulate IFN-β secretion prompts a shift in neutrophil polarization from the N2 to the N1 phenotype. This strategic repolarization remodels the tumor immune microenvironment, making the infiltration and activation of CD8+ T cells possible. Through these orchestrated mechanisms, the combined employment of Salmonella and MnO2 attains the synergistic enhancement of anti-tumor efficacy, achieving the complete inhibition of tumor growth within 20 days and an impressive 80% survival rate within 40 days, with no discernible signs of significant adverse effects. Our study not only unveils the crucial in vivo constraints obstructing microbial immune therapy but also sets out an innovative strategy to augment its efficacy. These findings pave the way for advancements in cell-based immunotherapy centered on leveraging the potential of neutrophils.

Protein-based nanoparticles (PNPs) in tumor therapy hold immense potential, combining targeted delivery, minimal toxicity, and customizable properties, thus paving the way for innovative approaches to cancer treatment. Understanding the various methods available for their production is crucial for researchers and scientists aiming to harness these nanoparticles for diverse applications, including tumor therapy, drug delivery, imaging, and tissue engineering. This review delves into the existing techniques for producing PNPs and PNP/drug complexes, while also exploring alternative novel approaches. The methods outlined in this study were divided into three key categories based on their shared procedural steps: solubility change, solvent substitution, and thin flow methods. This classification simplifies the understanding of the underlying mechanisms by offering a clear framework, providing several advantages over other categorizations. The review discusses the principles underlying each method, highlighting the factors influencing the nanoparticle size, morphology, stability, and functionality. It also addresses the challenges and considerations associated with each method, including the scalability, reproducibility, and biocompatibility. Future perspectives and emerging trends in PNPs\' production are discussed, emphasizing the potential for innovative strategies to overcome current limitations, which will propel the field forward for biomedical and therapeutic applications.

Living therapy based on bacterial cells has gained increasing attention for their applications in tumor treatments. Bacterial cells can naturally target to tumor sites and active the innate immunological responses. The intrinsic advantages of bacteria attribute to the development of biohybrid living carriers for targeting delivery toward hypoxic environments. The rationally engineered bacterial cells integrate various functions to enhance the tumor therapy and reduce toxic side effects. In this review, the antitumor effects of bacteria and their application are discussed as living therapeutic agents across multiple antitumor platforms. The various kinds of bacteria used for cancer therapy are first introduced and demonstrated the mechanism of antitumor effects as well as the immunological effects. Additionally, this study focused on the genetically modified bacteria for the production of antitumor agents as living delivery system to treat cancer. The combination of living bacterial cells with functional nanomaterials is then discussed in the cancer treatments. In brief, the rational design of living therapy based on bacterial cells highlighted a rapid development in tumor therapy and pointed out the potentials in clinical applications.

Pancreatic cancer remains a formidable challenge in oncology due to its aggressive nature and limited treatment options. The dense stroma surrounding pancreatic tumors not only provides structural support but also presents a formidable barrier to effective therapy, hindering drug penetration and immune cell infiltration. This review delves into the intricate interplay between stromal components and cancer cells, highlighting their impact on treatment resistance and prognosis. Strategies for stromal remodeling, including modulation of cancer-associated fibroblasts (CAFs), pancreatic stellate cells (PSCs) activation states, and targeting extracellular matrix (ECM) components, are examined for their potential to enhance drug penetration and improve therapeutic efficacy. Integration of stromal remodeling with conventional therapies, such as chemotherapy and immunotherapy, is discussed along with the emerging field of intelligent nanosystems for targeted drug delivery. This comprehensive overview underscores the importance of stromal remodeling in pancreatic cancer treatment and offers insights into promising avenues for future research and clinical translation.

The translation of Fe-based agents for ferroptosis tumor therapy is restricted by the unstable iron valence state, the harsh catalytic environment, and the complex tumor self-protection mechanism. Herein, we developed a stable nickel-based single-atom-metal-clusters (NSAMCs) biocatalyst for efficient tumor ferroptosis therapy. NSAMCs with a nanowire-like nanostructure and hydrophilic functional groups exhibit good water-solubility, colloidal stability, negligible systemic toxicity, and target specificity. In particular, NSAMCs possess excellent peroxidase-like and glutathione oxidase-like activities through the synergistic influence between metal clusters and single atoms. The dual-enzymatic performance enables NSAMCs to synergistically promote efficient ferroptosis of cancer cells through lipid peroxidization aggregation and glutathione peroxidase 4 inactivation. Importantly, NSAMCs highlight the boost of ferroptosis tumor therapy via the synergistic effect between single-atoms and metal clusters, providing a practical and feasible paradigm for further improving the efficiency of ferroptosis tumor treatment.