The Combination of Glycolytic Inhibitor 2-Deoxyglucose and Microbubbles Increases the Effect of 5-Aminolevulinic Acid-Sonodynamic Therapy in Liver Cancer Cells

Ultrasound-Targeted Microbubble Destruction Enhances the Inhibitory Effect of Sonodynamic Therapy against Hepatocellular Carcinoma

Purpose: To assess the anticancer effect of microbubbles (MBs) in combination with sinoporphyrin sodium (DVDMS)-mediated sonodynamic therapy (SDT) for the in vitro and in vivo treatment of hepatocellular carcinoma (HCC). Methods: HepG2 cells were used for in vitro experiments. Reactive oxygen species (ROS) production was detected using 2',7'-dichlorodihydrofluorescein diacetate and singlet oxygen sensor green in vitro and in solution, respectively. Cytotoxicity was evaluated using a Cell Counting Kit 8 assay and the calcein AM/PI double-staining method. Annexin V-FITC/PI staining was employed to analyze the rate of cell apoptosis. Cell surface calreticulin exposure, high mobility group box 1 release, and adenosine triphosphate secretion were measured to detect immunogenic cell death (ICD). The anticancer effect of the combination therapy was further assessed in Hepa1-6 tumor-bearing mice. Results: Compared with SDT alone, ROS production in the MBs + SDT group was enhanced 1.2-fold (p < 0.0001). The cytotoxic effect of DVDMS-mediated SDT on HepG2 cells was concentration-dependent, and the additional application of MBs increased cytotoxicity. Additionally, MBs augmented the SDT-induced apoptosis rate from 33.26 ± 13.48 to 72.95 ± 7.95% (p < 0.01). Notably, our results demonstrated that MBs can enhance SDT-induced ICD. In in vivo experiments, SDT combined with MBs significantly reduced tumor volume, with negligible differences in mouse body weight. Furthermore, MBs effectively enhanced SDT-induced tumor tissue destruction. Conclusion: The present study indicates that MBs can markedly improve the anticancer effects of SDT in HCC.

Advancements in nano drug delivery system for liver cancer therapy based on mitochondria-targeting

Based on poor efficacy and non-specific toxic side effects of conventional drug therapy for liver cancer, nano-based drug delivery system (NDDS) offers the advantage of drug targeting delivery. Subcellular targeting of nanomedicines on this basis enables more precise and effective termination of tumor cells. Mitochondria, as the crucial cell powerhouse, possesses distinctive physical and chemical properties in hepatoma cells different from that in hepatic cells, and controls apoptosis, tumor metastasis, and cellular drug resistance in hepatoma cells through metabolism and dynamics, which serves as a good choice for drug targeting delivery. Thus, mitochondria-targeting NDDS have become a recent research focus, showcasing the design of cationic nanoparticles, metal nanoparticles, mitochondrial peptide modification and so on. Although many studies have shown good results regarding anti-tumor efficacy, it is a long way to go before the successful translation of clinical application. Based on these, we summarized the specificity and importance of mitochondria in hepatoma cells, and reviewed the current mitochondria-targeting NDDS for liver cancer therapy, aiming to provide a better understanding for current development process, strengths and weaknesses of mitochondria-targeting NDDS as well as informing subsequent improvements and developments.

Bibliometric and visualized analysis of ultrasound combined with microbubble therapy technology from 2009 to 2023

Background

In recent years, with the rapid advancement of fundamental ultrasonography research, the application of ultrasound in disease treatment has progressively increased. An increasing body of research indicates that microbubbles serve not only as contrast agents but also in conjunction with ultrasound, enhancing cavitation effects and facilitating targeted drug delivery, thereby augmenting therapeutic efficacy. The objective of this study is to explore the current status and prevailing research trends in this field from 2009 to 2023 through bibliometric analysis and to forecast future developmental trajectories.

Methods

We selected the Science Citation Index Expanded (SCI-Expanded) from the Web of Science Core Collection (WOSCC) as our primary data source. On 19 January 2024, we conducted a comprehensive search encompassing all articles and reviews published between 2009 and 2023 and utilized the bibliometric online analysis platform, CiteSpace and VOSviewer software to analyze countries/regions, institutions, authors, keywords, and references, used Microsoft Excel 2021 to visualize the trends of the number of articles published by year.

Results

Between 1 January 2009, and 31 December 2023, 3,326 publications on ultrasound combined with microbubble therapy technology were included. There were a total of 2,846 articles (85.6%) and 480 reviews (14.4%) from 13,062 scholars in 68 countries/regions published in 782 journals. China and the United States emerged as the primary contributors in this domain. In terms of publication output and global institutional collaboration, the University of Toronto in Canada has made the most significant contribution to this field. Professor Kullervo Hynynen has achieved remarkable accomplishments in this area. Ultrasound in Medicine and Biology is at the core of the publishing of research on ultrasound combined with microbubble therapy technology. Keywords such as "sonodynamic therapy," "oxygen," "loaded microbubbles" and "Alzheimer's disease" indicate emerging trends in the field and hold the potential to evolve into significant areas of future investigation.

Conclusion

This study provides a summary of the key contributions of ultrasound combined with microbubble therapy to the field's development over the past 15 years and delves into the historical underpinnings and contemporary trends of ultrasound combined with microbubble therapy technology, providing valuable guidance for researchers.

Mitochondria-targeted organic sonodynamic therapy agents: concept, benefits, and future directions

Sonodynamic therapy (SDT) is an emerging and potentially less invasive therapeutic approach for cancer that employs ultrasound (US)-sensitive agents combined with US irradiation to generate cytotoxic reactive oxygen species (ROS) in deep tumor regions. Among various cellular organelles, the mitochondria are particularly susceptible to ROS, making them an attractive target for SDT. Organic-based SDT agents with mitochondria-targeting affinity have gained considerable interest as potential alternatives to conventional SDT agents, offering significant advantages in the field of SDT. However, to date, a comprehensive review focusing on mitochondria-targeted SDT agents has not yet been published. In this review, we provide an overview of the general concept, importance, benefits, and limitations of mitochondria-targeted organic SDT agents in comparison to conventional SDT methods. Finally, we discuss the current challenges and future directions for the design and development of efficient SDT agents. By addressing these issues, we aim to stimulate further research and advancements in the field of mitochondria-targeted SDT, ultimately facilitating the translation of these agents into clinical applications.

Modulating Glycolysis to Improve Cancer Therapy

Cancer cells undergo metabolic reprogramming and switch to a 'glycolysis-dominant' metabolic profile to promote their survival and meet their requirements for energy and macromolecules. This phenomenon, also known as the 'Warburg effect,' provides a survival advantage to the cancer cells and make the tumor environment more pro-cancerous. Additionally, the increased glycolytic dependence also promotes chemo/radio resistance. A similar switch to a glycolytic metabolic profile is also shown by the immune cells in the tumor microenvironment, inducing a competition between the cancer cells and the tumor-infiltrating cells over nutrients. Several recent studies have shown that targeting the enhanced glycolysis in cancer cells is a promising strategy to make them more susceptible to treatment with other conventional treatment modalities, including chemotherapy, radiotherapy, hormonal therapy, immunotherapy, and photodynamic therapy. Although several targeting strategies have been developed and several of them are in different stages of pre-clinical and clinical evaluation, there is still a lack of effective strategies to specifically target cancer cell glycolysis to improve treatment efficacy. Herein, we have reviewed our current understanding of the role of metabolic reprogramming in cancer cells and how targeting this phenomenon could be a potential strategy to improve the efficacy of conventional cancer therapy.

Novel mutation in hexokinase 2 confers resistance to 2-deoxyglucose by altering protein dynamics

Glucose is central to many biological processes, serving as an energy source and a building block for biosynthesis. After glucose enters the cell, hexokinases convert it to glucose-6-phosphate (Glc-6P) for use in anaerobic fermentation, aerobic oxidative phosphorylation, and the pentose-phosphate pathway. We here describe a genetic screen in Saccharomyces cerevisiae that generated a novel spontaneous mutation in hexokinase-2, hxk2^G238V, that confers resistance to the toxic glucose analog 2-deoxyglucose (2DG). Wild-type hexokinases convert 2DG to 2-deoxyglucose-6-phosphate (2DG-6P), but 2DG-6P cannot support downstream glycolysis, resulting in a cellular starvation-like response. Curiously, though the hxk2^G238V mutation encodes a loss-of-function allele, the affected amino acid does not interact directly with bound glucose, 2DG, or ATP. Molecular dynamics simulations suggest that Hxk2^G238V impedes sugar binding by altering the protein dynamics of the glucose-binding cleft, as well as the large-scale domain-closure motions required for catalysis. These findings shed new light on Hxk2 dynamics and highlight how allosteric changes can influence catalysis, providing new structural insights into this critical regulator of carbohydrate metabolism. Given that hexokinases are upregulated in some cancers and that 2DG and its derivatives have been studied in anti-cancer trials, the present work also provides insights that may apply to cancer biology and drug resistance.

Glucose fuels many of the energy-production processes required for normal cell growth. Before glucose can participate in these processes, it must first be chemically modified by proteins called hexokinases. To better understand how hexokinases modify glucose—and how mutations in hexokinase genes might confer drug resistance—we evolved resistance in yeast to a toxic hexokinase-binding molecule called 2DG. We discovered a mutation in the hexokinase gene that confers 2DG resistance and reduces the protein’s ability to modify glucose. Biochemical analyses and computer simulations of the hexokinase protein suggest that the mutation diminishes glucose binding by altering enzyme flexibility. This work shows how cells can evolve resistance to toxins via only modest changes to protein structures. Furthermore, because cancer-cell hexokinases are particularly active, 2DG has been studied as cancer chemotherapy. Thus, the insights this work provides might also apply to cancer biology.

Sonodynamic therapy: Ultrasound parameters and in vitro experimental configurations

Sonodynamic therapy (SDT) is a new therapeutic modality for noninvasive cancer treatment based on the association of ultrasound and sonosensitizer drugs. Up to date, there is not a consensus on the standardization of the experimental conditions for the in vitro studies to correctly assess cell viability during SDT. Therefore, this review article mainly describes how the main ultrasound parameters and experimental setups of ultrasound application in vitro studies can influence the SDT bioeffects/response. The sonodynamic action is impacted by the combination of frequency, intensity, duty cycle, and ultrasound application time. The variation of experimental setups in cell culture, such as the transducer position, cell-transducer distance, coupling medium thickness, or type of culture, also influences the sonodynamic response. The intensity, duty cycle, and sonication duration increase cytotoxicity and reactive oxygen species production. For similar ultrasound parameters, differences in the experimental configuration impact cell death in vitro. Four main experimental setups are used to assess for SDT in cell culture (i) a planar transducer placed directly in contact with the bottom of the culture microplate; (ii) microplate positioned in the transducer's far-field using a water tank; (iii) sealed cell culture tubes immersed in water away from the transducer; and (iv) transducer dipped directly into the well with cell culture. Because of the significant variations in the experimental setups, sonodynamic response can significantly vary, and the translation of these results for in vivo experimentation is difficult. Therefore, a well-designed and detailed in vitro experimental setup is vital for understanding the interactions among the biological medium, the sonosensitizer, and the ultrasound for the in vitro to in vivo translation in SDT.

5-Aminolevulinic acid hydrochloride loaded microbubbles-mediated sonodynamic therapy in pancreatic cancer cells

5-Aminolevulinic acid hydrochloride (ALA)-mediated sonodynamic therapy (SDT) had anti-tumour effect on pancreatic cancer cells. Hence, ALA loaded lipid/poly(lactic-co-glycolic acid) (PLGA) microbubbles (MBs)-mediated SDT for pancreatic cancer has great potential. The average size of ALA-lipid MBs and ALA-PLGA MBs was about 3.0 µm. The two kinds of MBs had good biocompatibility to normal HPDE6-C7 cells and were not toxic to pancreatic cancer cells. Compared with ALA-induced SDT, a statistically significant decrease in cell viability was observed in ALA lipid/PLGA MBs combined with ultrasound groups in AsPC-1 and BxPC-3 cells (p < .05). Obvious effect on the apoptotic rate, apoptosis and pyroptosis morphology, enhanced reactive oxygen species was found in ALA-lipid/PLGA MBs mediated SDT in vitro. Through in vivo study, we found ALA-lipid/PLGA MBs-mediated SDT was a promise treatment for pancreatic cancer.

Curcumin-Loaded Poly(L-lactide-co-glycolide) Microbubble-Mediated Sono-photodynamic Therapy in Liver Cancer Cells

Sono-photodynamic therapy (SPDT) activates the same photo-/sonosensitizer and exerts more marked antitumor effects than sonodynamic therapy or photodynamic therapy. We aimed to explore the utilization of curcumin (CUR)-loaded poly(L-lactide-co-glycolide) microbubble (MB)-mediated SPDT (CUR-PLGA-MB-SPDT) in HepG2 liver cancer cells. The cytotoxicity and intracellular accumulation of CUR were determined. We used 40 µM CUR as the photo-/sonosensitizer for 3 h. In a comparison of CUR-SDT or CUR-PDT, HepG2 cell viability decreased and apoptotic rate increased in CUR-SPDT. The CUR-PLGA MBs had round spheres with smooth surfaces and an average size of 3.7 µm. In CUR-PLGA MBs, drug entrapment efficiency and drug-loading capacity were 74.29 ± 2.60% and 17.14 ± 0.60%, respectively. CUR-loaded PLGA MBs (CUR-PLGA MBs) had good biocompatibility with normal L02 cells and were almost non-cytotoxic to HepG2 cells. Among CUR-SDT, CUR-PDT, CUR-SPDT or CUR-PLGA-MB-SDT, the cell CUR-PLGA-MB-SPDT had the lowest viability. Transmission electron microscopy revealed pyroptosis and apoptosis in the CUR-PLGA-MB-SPDT group; the potential mechanism was related to the mitochondrial membrane potential loss and increased production of intracellular reactive oxygen species. These findings suggested that CUR-PLGA-MB-SPDT may be a promising treatment for liver cancer.

Hematoporphyrin monomethyl ether-mediated sonodynamic therapy induces A-253 cell apoptosis

It has been found that >90% of oral cancer patients suffer from squamous cell carcinoma (SCC). The 5-year survival rate of SCC is ~50%, despite the availability of different treatments. Sonodynamic therapy (SDT) has been developed as a novel therapy for cancer, resisting bacterial infection and inhibiting atherosclerotic plaque progression. The present study investigated the efficacy of hematoporphyrin monomethyl ether (HMME)-mediated SDT on the A-253 epidermoid cancer cell line. The cytotoxicity of HMME and the survival rate of cells following SDT were examined by the MTT assay. Apoptosis and necrosis of cells were detected using flow cytometry with Annexin V and propidium iodide (PI) staining, and fluorescence microscopy with Hoechst 33258 and PI staining. Intracellular reactive oxygen species (ROS) and Ca²⁺ levels were measured using a fluorescence microscope based on 2′,7′-dichlorofluorescein diacetate and fluo-3/acetoxymethylester, respectively. Results of the MTT assay demonstrated that a lower concentration (<10 µg/ml) of HMME had no significant effect on the A-253 cells, but SDT combined with ultrasonic treatment for 1 min and 10 µg/ml HMME decreased the cell survival rate by 27%. Flow cytometry analysis revealed that A-253 cells in the SDT group had a higher rate of late apoptosis compared with the control group. Furthermore, fluorescence quantitation of apoptotic A-253 cells demonstrated that the percentages of apoptotic cells were increased in the ultrasound and SDT group compared with those in the control group. In the present study, the ROS level in the SDT group was elevated compared with that in the control group. The Ca²⁺ levels were increased to 181.2 and 268.7% in the ultrasound and SDT groups, respectively, relative to the control group. Taken together, the findings of the present study demonstrated that HMME-SDT significantly induces the apoptosis of A-253 cells together with intracellular ROS generation and Ca²⁺ overload. Thus, HMME-SDT may be a promising treatment option for patients with SCC.

Imaging-guided focused ultrasound-induced thermal and sonodynamic effects of nanosonosensitizers for synergistic enhancement of glioblastoma therapy

Glioblastoma (GBM) is a deadly brain tumor with poor prognosis and high mortality in patients. Given the low efficacy and serious side effects of current GBM therapy compared to those of conventional surgery, chemotherapy and radiation therapy, the development of a novel method for GBM management is very urgent. Sonodynamic therapy (SDT) has gained considerable attention in GBM therapy due to the advantages of deep tissue penetration and high biosafety. However, the low reactive oxygen species (ROS) generation efficacy of SDT has generally limited further applications and clinical translation. In this work, we report the simultaneous application of focused ultrasound-induced moderate thermal treatment (42 °C) and SDT for synergistic enhancement against GBM. Manganese ion (Mn2+)-chelated human serum albumin (HSA)-chlorin e6 (Ce6) nanoassemblies (HCM NAs) as targeting nanosonosensitizers were prepared using an assembly strategy. Our studies indicated that the HCM NAs had excellent T1-weighted contrast performance (12.2 mM-1 s-1) compared to that of clinically used Magnevist (4.3 mM-1 s-1) and achieved highly selective in vitro cell recognition and in vivo tumor-targeting magnetic resonance (MR) and fluorescence (FL) imaging with a signal-to-background ratio of 13.5 at 24 h post injection. Upon imaging-guided focused ultrasound irradiation, the temperature and reactive oxygen species (ROS) content of the tumor region increased simultaneously over time, achieving synergistic effects. The brain tumors were completely suppressed in subcutaneous mouse models of glioma, and the antitumor effect was greatly improved in orthotopic mouse models of glioma. It suggest that the synergistic treatment with moderate temperature and SDT induced by imaging-guided focused ultrasound is a promising platform against GMB, holds great potential in clinical settings.