Nanosensitizers for sonodynamic therapy for glioblastoma multiforme: current progress and future perspectives

Glioblastoma multiforme(GBM) is the most common primary malignant brain tumor, and it is associated with poor prognosis. Its characteristics of being highly invasive and undergoing heterogeneous genetic mutation, as well as the presence of the blood–brain barrier(BBB), have reduced the efficacy of GBM treatment. The emergence of a novel therapeutic method, namely, sonodynamic therapy(SDT), provides a promising strategy for eradicating tumors via activated sonosensitizers coupled with low-intensity ultrasound. SDT can provide tumor killing effects for deep-seated tumors, such as brain tumors. However, conventional sonosensitizers cannot effectively reach the tumor region and kill additional tumor cells, especially brain tumor cells. Efforts should be made to develop a method to help therapeutic agents pass through the BBB and accumulate in brain tumors. With the development of novel multifunctional nanosensitizers and newly emerging combination strategies, the killing ability and selectivity of SDT have greatly improved and are accompanied with fewer side effects. In this review, we systematically summarize the findings of previous studies on SDT for GBM, with a focus on recent developments and promising directions for future research.

Research progress on reactive oxygen species production mechanisms in tumor sonodynamic therapy

In recent years,because of the growing desire to improve the noninvasiveness and safety of tumor treatments,sonodynamic therapy has gradually become a popular research topic.However,due to the complexity of the therapeutic process,the relevant mechanisms have not yet been fully elucidated.One of the widely accepted possibilities involves the effect of reactive oxygen species.In this review,the mechanism of reactive oxygen species production by sonodynamic therapy(SDT)and ways to enhance the sonodynamic production of reactive oxygen species are reviewed.Then,the clinical application and limitations of SDT are discussed.In conclusion,current research on sonodynamic therapy should focus on the development of sonosensitizers that efficiently produce active oxygen,exhibit biological safety,and promote the clinical transformation of sonodynamic therapy.

Recent advances of sonodynamic therapy in cancer treatment

Sonodynamic therapy(SDT) is an emerging approach that involves a combination of low-intensity ultrasound and specialized chemical agents known as sonosensitizers. Ultrasound can penetrate deeply into tissues and can be focused into a small region of a tumor to activate a sonosensitizer which offers the possibility of non-invasively eradicating solid tumors in a site-directed manner.In this article, we critically reviewed the currently accepted mechanisms of sonodynamic action and summarized the classification of sonosensitizers. At the same time, the breath of evidence from SDT-based studies suggests that SDT is promising for cancer treatment.

Sonodynamic Antitumor Effect of Benzoporphyrin Derivative Monoacid Ring A on KLN205 Cells

Sonodynamic therapy is a new cancer treatment based on the synergetic effect of ultrasound and a drug. In this study, ultrasonically induced antitumor effects of benzoporphyrin derivative monoacid ring A (BPD-MA) on KLN205 cells were investigated. KLN205 cells were irradiated at an ultrasonic frequency of 3 MHz with 10 μg/ml BPD-MA. The ultrasonically induced cell damage significantly increased as an ultrasonic intensity and ultrasound exposure time increased. Confocal microscopic examination revealed that the irradiated cells were induced chromatin condensation and phosphatidylserine exposure. The synergistic effect of the ultrasound exposure and BPD-MA on the tumor cell adhesion rate was significant.

Modulation of reactive oxygen species to enhance sonodynamic therapy

Reactive oxygen species(ROS),involving in many biological reactions,play an important role in disease treatment.Among the various ROS-based therapeutic modalities,sonodynamic therapy(SDT)stands out with its unique advantages.In turn,the SDT efficacy is mainly dependent on the ROS levels in the disease microenvironment.Therefore,in recent years,researchers have extensively investigated SDT with high ROS generation capacity.In this review,we focus on effective strategies to improve the therapeutic ef-ficiency of SDT by modulating ROS,overview the basic mechanisms of ROS generation by sonosensitizers,highlight the rational design of sonosensitizers,and summarize strategies to improve the SDT efficacy by modulating disease microenvironment.In addition,multiple ROS synergistic treatment modalities and the prospect of SDT are discussed.We believe that the understanding and exploration of SDT enhancement strategies will facilitate the clinical translation of SDT.

Nanoengineered sonosensitive platelets for synergistically augmented sonodynamic tumor therapy by glutamine deprivation and cascading thrombosis

Ultrasound(US)-activated sonodynamic therapy(SDT)stands for a distinct antitumor modality because of its attractive characteristics including intriguing noninvasiveness,desirable safety,and high tissue penetration depth,which,unfortunately,suffers from compromised therapeutic efficacy due to cancer cell-inherent adaptive mechanisms,such as glutathione(GSH)neutralization response to reactive oxygen species(ROS),and glutamine addictive properties of tumors.In this work,we developed a biological sonosensitive platelet(PLT)pharmacytes for favoring US/GSH-responsive combinational therapeutic of glutamine deprivation and augmented SDT.The amino acid transporter SLC6A14 blockade agentα-methyl-DL-tryptophan(α-MT)-loaded and MnO_(2)-coated porphyrinic metal-organic framework(MOF)nanoparticles were encapsulated in the PLTs through the physical adsorption of electrostatic attraction and the intrinsic endocytosis of PLTs.When the sonosensitive PLT pharmacytes reached tumor sites through their natural tendencies to TME,US stimulated the PLTs-loaded porphyrinic MOF to generate ROS,resulting in morphological changes of the PLTs and the release of nanoparticles.Subsequently,intracellular high concentration of GSH and extracellular spatio-temporal controlled US irradiation programmatically triggered the release ofα-MT,which enabled the synergistically amplified SDT by inducing amino acid starvation,inhibiting mTOR,and mediating ferroptosis.In addition,US stimulation achieved the targeted activation of PLTs at tumor vascular site,which evolved from circulating PLTs to dendritic PLTs,effectively blocking the blood supply of tumors through thrombus formation,and revealing the encouraging potential to facilitate tumor therapeutics.

Recent advances in nanomaterials for sonodynamic therapy

Sonodynamic therapy(SDT),as a novel non-invasive strategy for eliminating tumor,has the advantages of deeper tissue penetration,fewer side effects,and better patient compliance,compared with photodynamic therapy(PDT).In SDT,ultrasound was used to activate sonosensitizer to produce cytotoxic reactive oxygen species(ROS),induce the collapse of vacuoles in solution,and bring about irreversible damage to cancer cells.In recent years,much effort has been devoted to developing highly efficient sonosensitizers which can efficiently generate ROS.However,the traditional organic sonosensitizers,such as porphyrins,hypericin,and curcumins,suffer from complex synthesis,poor water solubility,and low tumor targeting efficacy which limit the benefits of SDT.In contrast,inorganic sonosensitizers show good in vivo stability,controllable physicochemical properties,ease of achieving multifunctionality,and high tumor targeting,which greatly expanded their application in SDT.In this review,we systematically summarize the nanomaterials which act as the carrier of molecular sonosensitizers,and directly produce ROS under ultrasound.Moreover,the prospects of inorganic nanomaterials for SDT application are also discussed.

酞菁铁纳米点用于化学催化-声动力肿瘤联合治疗

声动力疗法(SDT)是一种新型无创治疗方式,由于其较强的组织穿透深度和较高的安全性而受到广泛关注.然而,目前声敏剂仍存在声敏化效率低的局限性,从而限制了其治疗效果和生物应用.因此,开发安全高效的声敏剂至关重要.本文中,我们通过简便的高温有机相法合成了一种新型超小酞菁铁纳米点(FePc NDs)声敏剂用于化学催化与声动力联合肿瘤治疗.高温处理后酞菁铁结中的N-H键的增强导致其声敏化作用大幅度提高,在超声作用下产生大量单线态氧(^(1)O_(2)).此外,由于Fe的存在,FePc NDs还可以通过芬顿催化反应生成羟基自由基(·OH),进一步提高活性氧治疗水平.值得注意的是,经过聚乙二醇(PEG)修饰的FePc-PEG NDs通过尾静脉注射入小鼠体内后呈现出较好的肿瘤富集能力.在超声作用下,FePc-PEG NDs具有明显的细胞杀伤效果和肿瘤抑制作用.更重要的是,得益于超小纳米结构,FePc-PEG NDs更易于从体内代谢,未引起明显的生物毒性,证明其具有良好的生物安全性.在此研究中,FePc-PEG NDs做为一种高效低毒的新型声敏剂在肿瘤声动力治疗领域具有广阔的应用前景.

Titanium carbide nanosheets with defect structure for photothermal-enhanced sonodynamic therapy

Sonodynamic therapy(SDT)has attracted widespread interest in biomedicine,owing to its novel and noninvasive therapeutic method triggered by ultrasound(US).Herein,the Ti_(3)C_(2) MXene nanosheets(Ti_(3)C_(2) NSs)are developed as good sonosensitizers via a two-step method of chemical exfoliation and high-temperature treatment.With the high-temperature treatment,the oxygen defect of Ti_(3)C_(2) MXene nanosheets(H-Ti_(3)C_(2) NSs)is greatly increased.Therefore,the electron(e^(-))and hole(h^(+))generated by US can be separated faster due to the improved degree of oxidation,and then the recombination of e^(-)-h^(+)can be prevented with the abundant oxygen defect under US irradiation,which induced the sonodynamic efficiency greatly to improve around 3.7-fold compared with Ti_(3)C_(2) NSs without high-temperature treatment.After PEGylation,the H-Ti_(3)C_(2)-PEG NSs show good stability and biocompatibility.In vitro studies exhibit that the inherent property of mild photothermal effect can promote the endocytosis of H-Ti_(3)C_(2)-PEG NSs,which can improve the SDT efficacy.In vivo studies further display that the increased blood supply by the mild photothermal effect can significantly relieve hypoxia in the tumor microenvironment,showing photothermal therapy(PTT)enhanced SDT.Most importantly,the H-Ti_(3)C_(2)-PEG NSs can be biodegraded and excreted out of the body,showing no significant long-term toxicity.Our work develops the defective H-Ti_(3)C_(2) NSs as high-efficiency and safe sonosensitizers for photothermal-enhanced SDT of cancer,extending the biomedical application of MXene-based nanoplatforms.

Cancer-macrophage hybrid membrane-camouflaged photochlor for enhanced sonodynamic therapy against triple-negative breast cancer

Sonodynamic therapy(SDT)has aroused considerable momentum in cancer therapy due to its abilities of deep penetration,low toxicity,and noninvasion,while insufficient tumor accumulation of sonosensitizers is a major obstacle for SDT effect.Here,we developed a 4T1 cancer cell-macrophage hybrid membrane(HM)-camouflaged sonosensitizer nanoplatform by encapsulating photochlor(HPPH)-loaded albumin nanoparticles(PHNPs).The experimental results proved that the HM-coated biomimetic NPs(PHNPs@HM)could express the characteristic membrane proteins of both cancer cells and macrophages,remarkedly enhancing the effective targeting and endocytosis to 4T1 cells through homologous adhesion recognition and immune escaping.Meanwhile,as a novel sonosensitizer,HPPH could generate amount of reactive oxygen species(ROS)under ultrasound(US)irradiation and exhibit obvious SDT efficiency to inhibit 4T1 tumor growth through ROS-induced cell apoptosis.This study provides a novel and multifunctional biomimetic sonosensitizer system to enhance SDT efficiency.

Development of porphyrin and titanium dioxide sonosensitizers for sonodynamic cancer therapy

Sonodynamic therapy for malignant tumours has gained much attention for its deep penetration effect and efficient tumour killing ability.The design,modification,and utilization of sonosensitizers are important aspects of sonodynamic therapy.As an essential factor in this process,highly effective sonosensitizers should be developed to facilitate the clinical applications of sonodynamic therapy.This review takes porphyrin-and titanium dioxide(TiO_(2))-based systems as representative organic and inorganic sonosensitizers respectively,and summarizes their characteristics and biological effects as sonodynamic therapy.Upon discovery of novel sonosensitizers,sonodynamic therapy becomes an efficient means of adjuvant therapy for the treatment of malignant tumours.