Oxygen-evolving photosynthetic cyanobacteria for 2D bismuthene radiosensitizer-enhanced cancer radiotherapy

Biomimetic Nanoplatform-Mediated Protective Autophagy Blockage Enhancing Sonodynamic and Ca2+-Overload Combined Therapy for Colon Cancer

The application of a multimodal combination therapy based on a targeted nanodelivery system has been demonstrated to be more valuable in the treatment of cancer. In this work, a hollow polydopamine delivery system (CCC@HP@M) was designed to achieve sonodynamic and calcium-overload combined therapy for colon cancer. The CCC@HP@M exhibits both homologous tumour-targeting ability and pH-responsive drug release properties, enabling the simultaneous targeted delivery of CaO2 nanoparticles/sonosensitizer Ce6/autophagy inhibitor CQ. The CaO2 nanoparticles as calcium agents capable of triggering Ca2+ overload in tumor cells. The oxidative stress produced by sonodynamic therapy is facilitated by the disruption of calcium homeostasis to enhance the effect of Ca2+ overload-induced apoptosis. Furthermore, the O2 produced by CaO2 augments the sensitization of sonodynamic therapy. The autophagy inhibitor CQ can inhibit protective cellular autophagy, which is activated by sonodynamic therapy and Ca2+ overload. Consequently, autophagy blockage can ensure the therapeutic effect of sonodynamic and Ca2+-overload combined therapy for colon cancer. The results of experiments in vitro and in vivo demonstrate that the stimulus-responsive targeted delivery system achieves autophagy blockage augmented sonodynamic and Ca2+-overload combined therapy of colon cancer. This work offers a promising theoretical basis for optimizing combined treatment strategies for tumors and clinical translational applications.

Myriad factors and pathways influencing tumor radiotherapy resistance

Radiotherapy is a cornerstone in the treatment of various tumors, yet radioresistance often leads to treatment failure and tumor recurrence. Several factors contribute to this resistance, including hypoxia, DNA repair mechanisms, and cancer stem cells. This review explores the diverse elements that drive tumor radiotherapy resistance. Historically, resistance has been attributed to cellular repair and tumor repopulation, but recent research has expanded this understanding. The tumor microenvironment - characterized by hypoxia, immune evasion, and stromal interactions - further complicates treatment. Additionally, molecular mechanisms such as aberrant signaling pathways, epigenetic modifications, and non-B-DNA structures play significant roles in mediating resistance. This review synthesizes current knowledge, highlighting the interplay of these factors and their clinical implications. Understanding these mechanisms is crucial for developing strategies to overcome resistance and improve therapeutic outcomes in cancer patients.

Towards chlorocytes for therapeutic intravascular photosynthesis

Aerobic metabolism relies on external oxygen production through photosynthesis and its subsequent transport into each cell of the body via the cardiorespiratory system. This mechanism has successfully evolved over millions of years, enabling animals to inhabit most environments on Earth. However, the insufficient oxygen supply leads to several clinical problems, ranging from non-healing wounds to tumor resistance to therapy. Given that photosynthetic microorganisms are capable of producing oxygen and removing carbon dioxide from the environment, over the last decade, several groups worldwide have proposed their potential use as an alternative tissue oxygenation approach. While most studies have demonstrated safety and efficacy after local tissue administration, recent studies have also suggested that systemic administration could trigger intravascular photosynthesis. If successful, the development of a new generation of circulating cells, known as chlorocytes, may partially replace the role of erythrocytes in gas exchange within the body, without relying on external supply and vascular flow. This work reviews the existing literature on local and systemic administration of photosynthetic microorganisms, highlighting the main challenges in the field and potential solutions to unleash the enormous potential clinical impact of chlorocytes and intravascular photosynthesis. KEY POINTS: • Circulating photosynthetic microorganisms could deliver oxygen to tissues • Microalgae and cyanobacteria have shown safety and efficacy for oxygen delivery • Several key challenges need to be addressed for the clinical success of chlorocytes.

Biomedical application of microalgal-biomaterials hybrid system

Microalgae are a group of microorganisms containing chlorophyll A, which are highly photosynthetic and rich in nutrients. And they can produce multiple bioactive substances (peptides, proteins, polysaccharides, and fatty acids) for biomedical applications. Despite the unique advantages of microalgae-based biotherapy, the insufficient treatment efficiency limits its further application. With the development of nanotechnology, the combination of microalgae and biomaterials can improve therapeutic efficacies, which has attracted increasing attention. In this microalgal-biomaterials hybrid system, biomaterials with excellent optical and magnetic properties play an important role in biological therapy. Microalgae, as a natural vehicle, can increase oxygen content and alleviate hypoxia in diseased areas, further enhancing therapeutic effects. In this review, the synergistic therapeutic effects of microalgal-biomaterials hybrid system in different diseases (cancer, myocardial infarction, ischemia stroke, chronic infection, and intestinal diseases) are comprehensively summarized.

Biosynthesis of fungus-based oral selenium microcarriers for radioprotection and immuno-homeostasis shaping against radiation-induced heart disease

Radiation-induced heart disease (RIHD), characterized by severe oxidative stress and immune dysregulation, is a serious condition affecting cancer patients undergoing thoracic radiation. Unfortunately, clinical interventions for RIHD are lacking. Selenium (Se) is a trace element with excellent antioxidant and immune-modulatory properties. However, its application in heart radioprotection remains challenging. Herein, we developed a novel bioactive Cordyceps militaris-based Se oral delivery system (Se@CM), which demonstrated superior radioprotection effects in vitro against X-ray-induced damage in H9C2 cells through suppressing excessive ROS generation, compared to the radioprotectant Amifostine. Moreover, Se@CM exhibited exceptional cardioprotective effects in vivo against X-ray irradiation, reducing cardiac dysfunction and myocardial fibrosis by balancing the redox equilibrium and modulating the expression of Mn-SOD and MDA. Additionally, Se@CM maintained immuno-homeostasis, as evidenced by the upregulated population of T cells and M2 macrophages through modulation of selenoprotein expression after irradiation. Together, these results highlight the remarkable antioxidant and immunity modulation properties of Se@CM and shed light on its promising application for cardiac protection against IR-induced disease. This research provides valuable insights into developing effective strategies for preventing and managing RIHD.

Synergized photothermal therapy and magnetic field induced hyperthermia via bismuthene for lung cancer combinatorial treatment

Thanks to its intrinsic properties, two-dimensional (2D) bismuth (bismuthene) can serve as a multimodal nanotherapeutic agent for lung cancer acting through multiple mechanisms, including photothermal therapy (PTT), magnetic field-induced hyperthermia (MH), immunogenic cell death (ICD), and ferroptosis. To investigate this possibility, we synthesized bismuthene from the exfoliation of 3D layered bismuth, prepared through a facile method that we developed involving surfactant-assisted chemical reduction, with a specific focus on improving its magnetic properties. The bismuthene nanosheets showed high in vitro and in vivo anti-cancer activity after simultaneous light and magnetic field exposure in lung adenocarcinoma cells. Only when light and magnetic field are applied together, we can achieve the highest anti-cancer activity compared to the single treatment groups. We have further shown that ICD-dependent mechanisms were involved during this combinatorial treatment strategy. Beyond ICD, bismuthene-based PTT and MH also resulted in an increase in ferroptosis mechanisms both in vitro and in vivo, in addition to apoptotic pathways. Finally, hemolysis in human whole blood and a wide variety of assays in human peripheral blood mononuclear cells indicated that the bismuthene nanosheets were biocompatible and did not alter immune function. These results showed that bismuthene has the potential to serve as a biocompatible platform that can arm multiple therapeutic approaches against lung cancer.

Engineered photoresponsive biohybrids for tumor therapy

Engineered biohybrids have recently emerged as innovative biomimetic platforms for cancer therapeutic applications. Particularly, engineered photoresponsive biohybrids hold tremendous potential against tumors due to their intriguing biomimetic properties, photoresponsive ability, and enhanced biotherapeutic functions. In this review, the design principles of engineered photoresponsive biohybrids and their latest progresses for tumor therapy are summarized. Representative engineered photoresponsive biohybrids are highlighted including biomolecules-associated, cell membrane-based, eukaryotic cell-based, bacteria-based, and algae-based photoresponsive biohybrids. Representative tumor therapeutic modalities of the engineered photoresponsive biohybrids are presented, including photothermal therapy, photodynamic therapy, synergistic therapy, and tumor therapy combined with tissue regeneration. Moreover, the challenges and future perspectives of these photoresponsive biohybrids for clinical practice are discussed.

Application of nano-radiosensitizers in combination cancer therapy

Radiosensitizers are compounds or nanostructures, which can improve the efficiency of ionizing radiation to kill cells. Radiosensitization increases the susceptibility of cancer cells to radiation-induced killing, while simultaneously reducing the potentially damaging effect on the cellular structure and function of the surrounding healthy tissues. Therefore, radiosensitizers are therapeutic agents used to boost the effectiveness of radiation treatment. The complexity and heterogeneity of cancer, and the multifactorial nature of its pathophysiology has led to many approaches to treatment. The effectiveness of each approach has been proven to some extent, but no definitive treatment to eradicate cancer has been discovered. The current review discusses a broad range of nano-radiosensitizers, summarizing possible combinations of radiosensitizing NPs with several other types of cancer therapy options, focusing on the benefits and drawbacks, challenges, and future prospects.

Hypoxic microenvironment in cancer: molecular mechanisms and therapeutic interventions

Having a hypoxic microenvironment is a common and salient feature of most solid tumors. Hypoxia has a profound effect on the biological behavior and malignant phenotype of cancer cells, mediates the effects of cancer chemotherapy, radiotherapy, and immunotherapy through complex mechanisms, and is closely associated with poor prognosis in various cancer patients. Accumulating studies have demonstrated that through normalization of the tumor vasculature, nanoparticle carriers and biocarriers can effectively increase the oxygen concentration in the tumor microenvironment, improve drug delivery and the efficacy of radiotherapy. They also increase infiltration of innate and adaptive anti-tumor immune cells to enhance the efficacy of immunotherapy. Furthermore, drugs targeting key genes associated with hypoxia, including hypoxia tracers, hypoxia-activated prodrugs, and drugs targeting hypoxia-inducible factors and downstream targets, can be used for visualization and quantitative analysis of tumor hypoxia and antitumor activity. However, the relationship between hypoxia and cancer is an area of research that requires further exploration. Here, we investigated the potential factors in the development of hypoxia in cancer, changes in signaling pathways that occur in cancer cells to adapt to hypoxic environments, the mechanisms of hypoxia-induced cancer immune tolerance, chemotherapeutic tolerance, and enhanced radiation tolerance, as well as the insights and applications of hypoxia in cancer therapy.

Oxygen switches: Refueling for cancer radiotherapy

Radiotherapy remains the major therapeutic intervention for tumor patients. However, the hypoxic tumor microenvironment leads to treatment resistance. Recently, a burgeoning number of nano-radiosensitizers designed to increase the oxygen concentration in tumors were reported. These nano radiosensitizers served as oxygen carriers, oxygen generators, and even sustained oxygen pumps, attracting increased research interest. In this review, we focus on the novel oxygen-enrich nano radiosensitizers, which we call oxygen switches, and highlight their influence in radiotherapy through different strategies. Physical strategies-based oxygen switches carried O2 into the tumor via their high oxygen capacity. The chemical reactions to generate O2 in situ were triggered by chemical strategies-based oxygen switches. Biological strategies-based oxygen switches regulated tumor metabolism, remodeled tumor vasculature, and even introduced microorganisms-mediated photosynthesis for long-lasting hypoxia alleviating. Moreover, the challenges and perspectives of oxygen switches-mediated oxygen-enrich radiotherapy were discussed.

Nanomedicine embraces cancer radio-immunotherapy: mechanism, design, recent advances, and clinical translation

Cancer radio-immunotherapy, integrating external/internal radiation therapy with immuno-oncology treatments, emerges in the current management of cancer. A growing number of pre-clinical studies and clinical trials have recently validated the synergistic antitumor effect of radio-immunotherapy, far beyond the "abscopal effect", but it suffers from a low response rate and toxicity issues. To this end, nanomedicines with an optimized design have been introduced to improve cancer radio-immunotherapy. Specifically, these nanomedicines are elegantly prepared by incorporating tumor antigens, immuno- or radio-regulators, or biomarker-specific imaging agents into the corresponding optimized nanoformulations. Moreover, they contribute to inducing various biological effects, such as generating in situ vaccination, promoting immunogenic cell death, overcoming radiation resistance, reversing immunosuppression, as well as pre-stratifying patients and assessing therapeutic response or therapy-induced toxicity. Overall, this review aims to provide a comprehensive landscape of nanomedicine-assisted radio-immunotherapy. The underlying working principles and the corresponding design strategies for these nanomedicines are elaborated by following the concept of "from bench to clinic". Their state-of-the-art applications, concerns over their clinical translation, along with perspectives are covered.

The development of live microorganism-based oxygen shuttles for enhanced hypoxic tumor therapy

Hypoxia is a prominent feature of malignant tumors and contributes to tumor proliferation, metastasis, and drug resistance in various solid tumors. Therefore, improving tumor oxygenation is crucial for curing tumors. To date, multiple strategies, including oxygen delivering and producing materials, have been designed to increase the oxygen concentration in hypoxic tumors. However, the unsustainable supply of oxygen is still the main obstacle, resulting in a suboptimal outcome in treating oxygen-deprived tumors. Thus, a sufficient oxygen supply is highly desirable in the treatment of hypoxic tumors. Photosynthesis, as the main source of oxygen in nature through the conversion of light energy into chemical energy and oxygen, has been widely studied in scientific research. Moreover, photosynthetic microorganisms have been increasingly applied in cancer therapy by increasing oxygenation, which improves the therapeutic effect of oxygen-consuming tumor therapeutic tools such as radiotherapy and photodynamic therapy. In this review, we summarize recent advances in the design and manufacture of live bacteria as oxygen shuttles for a new generation of hypoxic tumor treatment strategies. Finally, current challenges and future directions are also discussed for successfully addressing hypoxic tumor issues.

Albumin-assembled copper-bismuth bimetallic sulfide bioactive nanosphere as an amplifier of oxidative stress for enhanced radio-chemodynamic combination therapy

The tumor microenvironment with overexpressed hydrogen peroxide (H2O2) and reinforced antioxidative system (glutathione, GSH) becomes a double-edged sword for the accessibility of nano-therapy. Since reactive oxygen species (ROS) are easily quenched by the developed antioxidative network, ROS-based treatments such as chemodynamic therapy (CDT) and radiotherapy (RT) for killing cancer cells are severely attenuated. To overcome such limitations, a bioactive nanosphere system is developed to regulate intracellular oxidative stress for enhanced radio-chemodynamic combination therapy by using bovine serum albumin (BSA) based bioactive nanospheres that are BSA assembled with in situ generated copper-bismuth sulfide nanodots and diallyl trisulfide (DATS). The copper-bismuth sulfide nanodots react with H2O2 to produce •OH and release Cu2+. Then, the Cu2+ further depletes GSH to generate Cu+ for more •OH generation in the way of Fenton-like reaction. Such a cascade reaction can initiate •OH generation and GSH consumption to realize CDT. The elevation of ROS triggered by the DATS from BBCD nanospheres further augments the breaking of redox balance for the increased oxidative stress in 4T1 cells. With the sensitization of increased oxidative stress and high Z element Bi, an enhanced radio-chemodynamic combination therapy is achieved. The current work provides an enhanced radio-chemodynamic combination treatment for the majority of solid tumors by using the co-assembled bioactive nanospheres as an amplifier of oxidative stress.