Sonodynamic therapy induces the interplay between apoptosis and autophagy in K562 cells through ROS

Nanotechnology-enabled sonodynamic therapy against malignant tumors

Sonodynamic therapy (SDT) is an emerging approach for malignant tumor treatment, offering high precision, deep tissue penetration, and minimal side effects. The rapid advancements in nanotechnology, particularly in cancer treatment, have enhanced the efficacy and targeting specificity of SDT. Combining sonodynamic therapy with nanotechnology offers a promising direction for future cancer treatments. In this review, we first systematically discussed the anti-tumor mechanism of SDT and then summarized the common nanotechnology-related sonosensitizers and their recent applications. Subsequently, nanotechnology-related therapies derived using the SDT mechanism were elaborated. Finally, the role of nanomaterials in SDT combined therapy was also introduced.

The association and application of sonodynamic therapy and autophagy in diseases

Sonodynamic therapy (SDT) is a new non-invasive treatment method proposed based on photodynamic therapy (PDT). It has advantages such as high precision, strong tissue penetration, minimal side effects, and good patient compliance. With the maturation of nanomedicine, the application of nanosonosensitizers has further propelled the development of SDT. In recent years, people have developed many new types of sonosensitizers and explored the mechanisms of SDT. Among them, the studies about the relationship between autophagy and SDT have attracted increasing attention. After the SDT, cells usually undergo autophagy as a self-protective mechanism to resist external stimuli and reduce cell damage, which is beneficial for the treatment of atherosclerosis (AS), diabetes, and myocardial infarction but counterproductive in cancer treatment. However, under certain treatment conditions, excessive upregulation of autophagy can also promote cell death, which is beneficial for cancer treatment. This article reviews the latest research progress on the relationship between SDT and autophagy in cancers, AS, diabetes, and myocardial infarction. We also discuss and propose the challenges and prospects in enhancing SDT efficacy by regulating autophagy, with the hope of promoting the development of this promising therapeutic approach.

IR-820@NBs Combined with MG-132 Enhances the Anti-Hepatocellular Carcinoma Effect of Sonodynamic Therapy

Purpose

Sonodynamic therapy (SDT) is a promising and significant measure for the treatment of tumors. However, the internal situation of hepatocellular carcinoma (HCC) is complex, separate SDT treatment is difficult to play a good therapeutic effect. Here, we used SDT combined with MG-132 to mediate apoptosis and autophagy of HCC cells to achieve the purpose of treatment of cancer.

Methods

To determine the generated reactive oxygen species (ROS) and the change of mitochondrial membrane potential (ΔΨm), HepG2 cells were stained by 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA) and 5,5',6,6'-Tetrachloro-1,1',3,3'-tetraethyl-imidacarbocyanine iodide (JC-1) staining to determine the IR-820@NBs-mediated SDT to achieve HCC therapy through the mitochondrial pathway. Cell counting kit 8 (CCK-8) assay and flow cytometry were used to detect cell viability and apoptosis rate of HepG2 cells. Autophagy was detected by mCherry-GFP-LC3B fluorescence labeling. Chloroquine (Cq) pretreatment was used to explore the relationship between autophagy and apoptosis. To detect the ability of HepG2 cells migration and invasion, cell scratch assay and transwell assay were used.

Results

The successfully prepared IR-820@NBs could effectively overcome the shortcomings of IR-820 and induce lethal levels of ROS by ultrasound irradiation. As a dual agonist of apoptosis and autophagy, MG-132 could effectively enhance the efficacy of SDT in the process of treating HCC. After pre-treatment with Cq, the cell activity increased and the level of apoptosis decreased, which proved that apoptosis and autophagy were induced by combined therapy, autophagy, and apoptosis have the synergistic anti-tumor effect, and part of apoptosis was autophagy-dependent. After combined therapy, the activity and invasive ability of HCC cells decreased significantly.

Conclusion

SDT combined with MG-132 in the process of treating liver cancer could effectively induce apoptosis and autophagy anti-tumor therapy, which is helpful to the research of new methods to treat liver cancer.

Current status and future perspective of sonodynamic therapy for cancer

There is a tremendous need for prevention and effective treatment of cancer due to the associated morbidity and mortality. In this study, we introduce sonodynamic therapy (SDT), which is expected to be a new cancer treatment modality. SDT is a promising option for minimally invasive treatment of solid tumors and comprises three different components: sonosensitizers, ultrasound, and molecular oxygen. These components are harmless individually, but in combination they generate cytotoxic reactive oxygen species (ROS). We will explore the molecular mechanism by which SDT kills cancer cells, the class of sonosensitizers, drug delivery methods, and in vitro and in vivo studies. At the same time, we will highlight clinical applications for cancer treatment. The progress of SDT research suggests that it has the potential to become an advanced field of cancer treatment in clinical application. In this article, we will focus on the mechanism of action of SDT and its application to cancer treatment, and explain key factors to aid in developing strategies for future SDT development.

Oncolytic Impediment/Promotion Balance Disruption by Sonosensitizer-Free Nanoplatforms Unfreezes Autophagy-Induced Resistance to Sonocatalytic Therapy

Autophagy as a double-edged sword features an oncolytic impediment/promotion balance, which manipulates tumor progression. From this perspective, a sonosensitizer-free targeting oncolytic nanoplatform (SFTON) consisting of chloroquine (CQ) and porphyrin-structured metal centers (PMCS) was engineered to break this balance for enhancing antitumor activity. Porphyrin structure retention in a ZIF-8-derived hydrophobic carbon skeleton retained high stability and high sonocatalytic activity, and the hydrophobic carbon skeleton capable of adsorbing air provided cavitation nuclei for further elevating sonocatalytic activity. More significantly, the encapsulated CQ as the autophagy inhibitor reprogrammed autophagy, terminated the autophagy-induced self-protection or self-detoxification, and unfroze the resistances to reactive oxygen species (ROS) therapy associated with ROS accumulation and ROS activity. Systematic experiments reveal the action principles and validate that the induced apoptosis and blockaded autophagosome escalation into the autolysosome were two activated pathways to magnify the antitumor sonocatalytic therapy. Contributed by these actions, the SFTON-unlocked oncolytic impediment/promotion balance disruption strategy acquired considerable antitumor outcomes in vivo and in vitro against liver tumor progression, especially after combining with AS1411-mediated active targeting. This impediment/promotion balance disruption enabled by the SFTON can serve as a general method to elevate ROS-based antitumor activity.

The crosstalk between sonodynamic therapy and autophagy in cancer

As a noninvasive treatment approach for cancer and other diseases, sonodynamic therapy (SDT) has attracted extensive attention due to the deep penetration of ultrasound, good focusing, and selective irradiation sites. However, intrinsic limitations of traditional sonosensitizers hinder the widespread application of SDT. With the development of nanotechnology, nanoparticles as sonosensitizers or as a vehicle to deliver sonosensitizers have been designed and used to target tissues or tumor cells with high specificity and accuracy. Autophagy is a common metabolic alteration in both normal cells and tumor cells. When autophagy happens, a double-membrane autophagosome with sequestrated intracellular components is delivered and fused with lysosomes for degradation. Recycling these cell materials can promote survival under a variety of stress conditions. Numerous studies have revealed that both apoptosis and autophagy occur after SDT. This review summarizes recent progress in autophagy activation by SDT through multiple mechanisms in tumor therapies, drug resistance, and lipid catabolism. A promising tumor therapy, which combines SDT with autophagy inhibition using a nanoparticle delivering system, is presented and investigated.

Defect Engineering Triggers Exceptional Sonodynamic Activity of Manganese Oxide Nanoparticles for Cancer Therapy

Sonodynamic therapy (SDT) has received increasing interest in cancer treatment, but its clinical application is still constrained by the low activity of sonosensitizers and their unclear mechanism. Herein, a kind of oxygen-deficient manganese oxide (MnOx) nanoparticles with greatly enhanced sonodynamic activity and good biocompatibility is developed as an advanced sonosensitizer. The introduced oxygen defects can remarkably enhance the electrical conductivity of manganese oxide (MnO) nanoparticles and serve as charge trapping sites to prohibit the electron-hole pair recombination upon ultrasound (US) irradiation. Such distinct merits promote the generation of reactive oxygen species (ROS), making MnOx as a decent sonosensitizer for SDT, and thus endowing MnOx with higher ROS production under US irradiation. As a demonstration, the MnOx nanoparticles decorated by 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (MnOx-DSPE-PEG), a biocompatible coverage to enhance the dispersion ability, achieve a superior tumor killing efficiency of 96%, substantially higher than the MnO-DSPE-PEG counterpart (9%). Our experimental results also reveal that MnOx-DSPE-PEG nanoparticles induce the death of tumor cells by targeting polyunsaturated fatty acids in their membrane with US-triggered ROS. Furthermore, the as-designed sonosensitizers exhibit negligible toxicity toward the treated mice.

Chemotherapy and Physical Therapeutics Modulate Antigens on Cancer Cells

Cancer cells possess specific properties, such as multidrug resistance or unlimited proliferation potential, due to the presence of specific proteins on their cell membranes. The release of proliferation-related proteins from the membrane can evoke a loss of adaptive ability in cancer cells and thus enhance the effects of anticancer therapy. The upregulation of cancer-specific membrane antigens results in a better outcome of immunotherapy. Moreover, cytotoxic T-cells may also become more effective when stimulated ex-vivo toward the anticancer response. Therefore, the modulation of membrane proteins may serve as an interesting attempt in anticancer therapy. The presence of membrane antigens relies on various physical factors such as temperature, exposure to radiation, or drugs. Therefore, changing the tumor microenvironment conditions may lead to cancer cells becoming sensitized to subsequent therapy. This paper focuses on the therapeutic approaches modulating membrane antigens and enzymes in anticancer therapy. It aims to analyze the possible methods for modulating the antigens, such as pharmacological treatment, electric field treatment, photodynamic reaction, treatment with magnetic field or X-ray radiation. Besides, an overview of the effects of chemotherapy and immunotherapy on the immunophenotype of cancer cells is presented. Finally, the authors review the clinical trials that involved the modulation of cell immunophenotype in anticancer therapy.

Cavitation assisted endoplasmic reticulum targeted sonodynamic droplets to enhanced anti-PD-L1 immunotherapy in pancreatic cancer

BACKGROUND

Sonodynamic therapy (SDT) induces immunogenic cell death (ICD) in tumors and promises to play an assistive role in immunotherapy in pancreatic cancer. However, the short half-life and limited diffusion distance of reactive oxygen species (ROS) impair ICD induction, especially in tumors with relatively poor blood perfusion and dense stroma.

RESULTS

To address this problem, we fabricated cavitation-assisted endoplasmic reticulum (ER) targeted sonodynamic nanodroplets (PMPS NDs, 329 nm). The good sonodynamic effect and precise endoplasmic reticulum target effect was verified. After intravenous injection, the cRGD peptide modified nanodroplets initially aggregated around the tumor vascular endothelial cells. Stimulated by ultrasound, the liquid-to-gas bubbles began to oscillate and cavitate. This acoustic droplet evaporation strategy facilitated transport of the nanoparticle across the vessel, with deep penetration. This loosened the tumor stroma and facilitated accumulation and penetration of loaded sonosensitizer after 6 h. The modified sonosensitizer can selectively accumulate in the ER to generate a large amount of ROS in situ, inducing potent ER stress, amplified ICD and dendritic cell maturation in vitro and in vivo. Furthermore, the elevated antitumor effect of SDT plus anti-PD-L1 immunotherapy was verified using an orthotopic tumor model.

CONCLUSIONS

This study reports a cavitation assisted ER targeted sonodynamic therapy that can enhance the effect of anti-PD-L1 immunotherapy effectively in orthotopic and distant pancreatic cancer.

Ultrasound Triggers Hypericin Activation Leading to Multifaceted Anticancer Activity

The use of ultrasound (US) in combination with a responsive chemical agent (sonosensitizer) can selectively trigger the agent's anticancer activity in a process called sonodynamic therapy (SDT). SDT shares some properties with photodynamic therapy (PDT), which has been clinically approved, but sets itself apart because of its use of US rather than light to achieve better tissue penetration. SDT provides anticancer effects mainly via the sonosensitizer-mediated generation of reactive oxygen species (ROS), although the precise nature of the underpinning mechanism is still under debate. This work investigates the SDT anticancer activity of hypericin (Hyp) in vitro in two- (2D) and three-dimensional (3D) HT-29 colon cancer models, and uses PDT as a yardstick due to its well-known Hyp phototoxicity. The cancer cell uptake and cellular localization of Hyp were investigated first to determine the proper noncytotoxic concentration and incubation time of Hyp for SDT. Furthermore, ROS production, cell proliferation, and cell death were evaluated after Hyp was exposed to US. Since cancer relapse and transporter-mediated multidrug resistance (MDR) are important causes of cancer treatment failure, the US-mediated ability of Hyp to elicit immunogenic cell death (ICD) and overcome MDR was also investigated. SDT showed strong ROS-mediated anticancer activity 48 h after treatment in both the HT-29 models. Specific damage-associated molecular patterns that are consistent with ICD, such as calreticulin (CRT) exposure and high-mobility group box 1 protein (HMGB1) release, were observed after SDT with Hyp. Moreover, the expression of the ABC transporter, P-glycoprotein (P-gp), in HT-29/MDR cells was not able to hinder cancer cell responsiveness to SDT with Hyp. This work reveals, for the first time, the US responsiveness of Hyp with significant anticancer activity being displayed, making it a full-fledged sonosensitizer for the SDT of cancer.

Antibacterial Sonodynamic Therapy: Current Status and Future Perspectives

Multidrug-resistant bacteria have emerged in both community and hospital settings, partly due to the misuse of antibiotics. The inventory of viable antibiotics is rapidly declining, and efforts toward discovering newer antibiotics are not yielding the desired outcomes. Therefore, alternate antibacterial therapies based on physical mechanisms such as light and ultrasound are being explored. Sonodynamic therapy (SDT) is an emerging therapeutic approach that involves exposing target tissues to a nontoxic sensitizing chemical and low-intensity ultrasound. SDT can enable site-specific cytotoxicity by producing reactive oxygen species (ROS) in response to ultrasound, which can be harnessed for treating bacterial infections. This approach can potentially be used for both superficial and deep-seated microbial infections. The majority of the sonosensitizers reported are nonpolar, exhibiting limited bioavailability and a high clearance rate in the body. Therefore, targeted delivery agents such as nanoparticle composites, liposomes, and microbubbles are being investigated. This article reviews recent developments in antibacterial sonodynamic therapy, emphasizing biophysical and chemical mechanisms, novel delivery agents, ultrasound exposure and image guidance strategies, and the challenges in the pathway to clinical translation.

Titaniumdioxide mediated sonophotodynamic therapy against prostate cancer

In this study, we aimed to investigate of antitumor efficiency of titanium dioxide mediated photodynamic (PDT), sonodynamic (SDT), and sonophotodynamic (SPDT) therapies with a possible mechanism against the PC3 prostate cancer cell line. SPDT is a new approach to cancer treatment that combines sonodynamic and photodynamic therapies. On the other hand, Titanium dioxide (TiO₂) has been used in many applications in pharmaceutical products and cosmetics, industrial products, and medicines. TiO₂ nanoparticles will be useful for the treatment of cancer with PDT and SDT as the sensitizers in medicine. In this study, TiO₂ nanoparticles were used for an in vitro comparison between the PDT, SDT, SPDT damages on prostate cancer cell lines. For this purpose, the cells were incubated in RPMI-1640 media with various concentrations of TiO₂ and subjected to 0,5 W/cm² ultrasound and/or 0,5 mJ/cm² light irradiation. The prostate cancer cells were irradiated with light and exposed with the US and both for SPDT in the presence and/or absence of TiO₂. Cell viability was measured using by MTT test after treatments. Investigate to apoptosis mechanism, Propidium iodide and Hoechst 33342 staining were used and the results showed that apoptotic cell bodies were increased compared with other groups. According to western blot analyses, caspase-3, caspase-8, PARP, and Bax levels were decreased after treatments, whereas the expression levels of caspase-9 were increased. Biochemical results showed that after treatments MDA levels were increased while SOD, CAT, GSH levels were decreased. In conclusion, TiO₂-mediated SPDT may provide a promising approach for prostate cancer therapy and might play a key role in the apoptotic mechanism of these treatments.

Involvement of hydrogen peroxide in sonodynamical effect with sinoporphyrin sodium in hypoxic situation

Sonodynamic therapy (SDT) represents a noninvasive therapeutic method via the activation of certain chemical sensitizers using low intensity ultrasound to generate various reactive oxygen species (ROS). In this work, we conducted systematic experiments to evaluate the production of hydrogen peroxide (H₂O₂) in sinoporphyrin sodium (DVDMS) mediated SDT (DVDMS-SDT). We found that the fluorescence intensities of H₂O₂ specific probe BES-H₂O₂ and Amplex Red increased significantly exposure to DVDMS-SDT while decreased with the introduction of catalase (H₂O₂ scavenger), indicating the production of H₂O₂. And the fluorescence intensity of H₂O₂ susceptible probes were positively correlated with DVDMS concentration, ultrasound intensity and irradiation time. Under the same molarity concentration, DVDMS has advantages over proto-porphyrin IX (PpIX) and hemoporrin monomethyl ether (HMME) in H₂O₂ production, indicating that the yield of H₂O₂ depends on the properties of sensitizer. More importantly, DVDMS-SDT is involved in the process of H₂O₂ even in the oxygen-free condition, showing its greater superiority for the treatment of tumor under hypoxia environment.

5-Aminolevulinic Acid Triggered by Ultrasound Halts Tumor Proliferation in a Syngeneic Model of Breast Cancer

Sonodynamic therapy is a bimodal therapeutic approach in which a chemical compound and ultrasound (US) synergistically act to elicit oxidative damage, triggering cancer cell death. Despite encouraging results, mainly for anticancer treatment, sonodynamics is still far from having a clinical application. Therefore, to close the gap between the bench and bedside, more in vivo studies are needed. In this investigation, the combined effect of 5-aminolevulinic acid (Ala), a natural porphyrin precursor, plus exposure to US, was investigated in vivo on a syngeneic breast cancer model. Real-time RT-PCR, Western blotting, and immunohistochemistry assays were performed to evaluate the effect of sonodynamic treatment on the main cancer hallmarks. The sonodynamic-treated group had a significant reduction (p ≤ 0.0001) in tumor size compared to the untreated group, and the Ala- and US-only treated groups, where a strong decrease (p ≤ 0.0001) in Ki67 protein expression was the most relevant feature of sonodynamic-treated cancer tissues. Moreover, oxidative stress was confirmed as the pivotal driver of the anticancer effect through cell cycle arrest, apoptosis, and autophagy; thus, sonodynamics should be explored further for cancer treatment.

Arsenic trioxide induces macrophage autophagy and atheroprotection by regulating ROS-dependent TFEB nuclear translocation and AKT/mTOR pathway

Inducing autophagy and inhibiting apoptosis may provide a therapeutic treatment for atherosclerosis (AS). For the treatment of progressive AS, arsenic trioxide (ATO) has been used to coat vascular stents. However, the effect of ATO on autophagy of macrophages is still unknown. Therefore, the aims of this study were to characterize the effects and the mechanism of actions of ATO on autophagy in macrophages. Our results showed that ATO-induced activation of autophagy was an earlier event than ATO-induced inhibition of the expression of apoptosis markers in macrophages and foam cells. Nuclear transcription factor EB (TFEB) prevents atherosclerosis by activating macrophage autophagy and promoting lysosomal biogenesis. Here, we report that ATO triggered the nuclear translocation of TFEB, which in turn promoted autophagy and autophagosome-lysosome fusion. Both the latter events were prevented by TFEB knockdown. Moreover, ATO decreased the p-AKT and p-mTOR in the PI3K/AKT/mTOR signaling pathway, thus inducing autophagy. Correspondingly, treatment with the autophagy inhibitor 3-methyladenine (3-MA) abolished the autophagy-inducing effects of ATO. Meanwhile, PI3K inhibitor (LY294002) and mTOR inhibitor (rapamycin) cooperated with ATO to induce autophagy. Furthermore, reactive oxygen species (ROS) were generated in macrophages after treatment with ATO. The ROS scavenger N-acetyl-1-cysteine (NAC) abolished ATO-induced nuclear translocation of TFEB, as well as changes in key molecules of the AKT/mTOR signaling pathway and downstream autophagy. More importantly, ATO promoted autophagy in the aorta of ApoE-/- mice and reduced atherosclerotic lesions in early AS, which were reversed by 3-MA treatment. In summary, our data indicated that ATO promoted ROS induction, which resulted in nuclear translocation of TFEB and inhibition of the PI3K/AKT/mTOR pathway. These actions ultimately promoted macrophage autophagy and reduced atherosclerotic lesions at early stages. These findings may provide a new perspective for the clinical treatment of early-stage atherosclerosis and should be further studied.

Sinoporphyrin sodium mediated sonodynamic therapy generates superoxide anions under a hypoxic environment

DVDMS-SDT induces G2/M arrest by superoxide anions.

Co-Immobilization of Ce6 Sono/Photosensitizer and Protonated Graphitic Carbon Nitride on PCL/Gelation Fibrous Scaffolds for Combined Sono-Photodynamic Cancer Therapy

Aiming at developing a moderate and efficient sono-photodynamic therapy for breast cancer, tissue engineering scaffolds may provide an easy and efficient strategy to eliminate serious side effects in conventional surgery or chemotherapy, and thus, they are highly desired. However, the development of ideal sono-photodynamic therapeutic scaffolds is always hindered by the poor stability and incompatibility between the different biomaterial components. Herein, the Food and Drug Administration (FDA)-approved sono/photosensitizer Chlorin e6 (Ce6) was successfully and tightly incorporated into electrospun polycaprolactone/gelatin (PG) scaffolds via positively charged protonated g-C₃N₄ nanosheets (pCN). The PG fibers were precoated with graphene oxide (GO) to enable the assembly of pCN on the surface through electrostatic interactions. The Ce6@pCN-GO-PG composite scaffolds exhibited good cytocompatibility and excellent sono-photodynamic activity, leading to distinctly boosted reactive oxygen species (ROS) generation and a 95.8% inactivation rate of breast cancer cells through a synergistic sono-photodynamic process triggered by an 808 nm laser and 1 MHz ultrasound (US) excitation, within the clinical therapeutic dose. The as-developed scaffolds with unique ultrasound cavitation therapeutic effects can be used not only for complete eradication of tumor cells after surgery but also as a cell behavior observation platform of sono-photodynamic cancer therapy.

Ultrasound-Activated Sensitizers and Applications

Modalities for photo-triggered anticancer therapy are usually limited by their low penetrative depth. Sonotheranostics especially sonodynamic therapy (SDT), which is different from photodynamic therapy (PDT) by the use of highly penetrating acoustic waves to activate a class of sound-responsive materials called sonosensitizers, has gained significant interest in recent years. The effect of SDT is closely related to the structural and physicochemical properties of the sonosensitizers, which has led to the development of new sound-activated materials as sonosensitizers for various biomedical applications. This Review provides a summary and discussion of the types of novel sonosensitizers developed in the last few years and outlines their specific designs and the potential challenges. The applications of sonosensitizers with various functions such as for imaging and drug delivery as well as in combination with other treatment modalities would provide new strategies for disease therapy.

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.

Acetylshikonin induces apoptosis of human leukemia cell line K562 by inducing S phase cell cycle arrest, modulating ROS accumulation, depleting Bcr-Abl and blocking NF-κB signaling

Acetylshikonin, a natural naphthoquinone derivative compound from Lithospermum erythrorhyzon, has been reported to kill bacteria, suppress inflammation, and inhibit tumor growth. However, the effect of acetylshikonin on human chronic myelocytic leukemia (CML) cells apoptosis and its detailed mechanisms remains unknown. The purpose of the present study was to investigate whether acetylshikonin could inhibit proliferation or induce apoptosis of the K562 cells, and whether by regulating the NF-κB signaling pathway to suppress the development of CML. K562 cells were treated with serial diluted acetylshikonin at different concentrations. Our data showed that K562 cell growth was significantly inhibited by acetylshikonin with an IC50 of 2.03 μM at 24 h and 1.13 μM at 48 h, with increased cell cycle arrest in S-phase. The results of annexin V-FITC/PI and AO/EB staining showed that acetylshikonin induced cell apoptosis in a dose-dependent manner. K562 cells treated with acetylshikonin underwent massive apoptosis accompanied by a rapid generation of reactive oxygen species (ROS). Scavenging the ROS completely blocked the induction of apoptosis following acetylshikonin treatment. The levels of the pro-apoptotic proteins Bax, cleaved caspase-9, cleaved PARP and cleaved caspase-3 increased with increased concentrations of acetylshikonin, while the level of the anti-apoptotic protein Bcl-2 was downregulated. The levels of Cyt C and AIF, which are characteristic proteins of the mitochondria-regulated intrinsic apoptotic pathway, also increased in the cytosol after acetylshikonin treatment. However, the mitochondrial fraction of Cyt C and AIF were decreased under acetylshikonin treatment. In addition, acetylshikonin decreased Bcr-Abl expression and inhibited its downstream signaling. Acetylshikonin could lead to a blockage of the NF-κB signaling pathway via decreasing nuclear NF-κB P65 and increasing cytoplasmic NF-κB P65. Moreover, acetylshikonin significantly inhibited the phosphorylation of IkBα and IKKα/β in K562 cells. These results demonstrated that acetylshikonin significantly inhibited K562 cell growth and induced cell apoptosis through the mitochondria-regulated intrinsic apoptotic pathway. The mechanisms may involve the modulating ROS accumulation, inhibition of NF-κB and BCR-ABL expression. The inhibition of BCR-ABL expression and the inactivation of the NF-κB signaling pathway caused by acetylshikonin treatment resulted in K562 cell apoptosis. Together, our results indicate that acetylshikonin could serve as a potential therapeutic agent for the future treatment of CML.

7-H-Pyrrolo[2,3-d]pyrimidine derivative acts as promising agent for gastric cancer treatment by inducing cell death

In the present study effect of 7-H-pyrrolo[2,3-d]pyrimidine derivative (7-HPPD) on viability of MKN28 and MKN74 gastric cancer cells was investigated. There was no significant change in GES-1 cell viability on treatment with 7-HPPD for 48 h. MKN28 and MKN74 cell viability was reduced to 21 and 23%, respectively, on treatment with 7-HPPD at concentration of 50 µM. Hoechst 33342 staining showed that the cells treated with 7-HPPD showed condensation of chromatin material, presence of apoptotic bodies and intense blue fluorescence. Treatment of MKN28 and MKN74 cells with 7-HPPD markedly increased the release of LDH. Z-VAD-FMK prevented 7-HPPD-induced suppression of MKN28 and MKN74 cell viability. Exposure to 15, 20, 25, 30 and 50 µM concentrations of 7-HPPD caused concentration-based increase in caspase-8, -9, -3 and cleaved PARP. A significant increase in ROS production was caused by 7-HPPD in MKN28 and MKN74 cells. Increasing the concentration of 7-HPPD from 10 to 50 µM did not increase the expression of RIP3 protein. In summary, 7-HPPD suppresses gastric cancer cell growth by inducing apoptosis through increase in caspase expression and ROS production. Consequently, 7-HPPD may be used for the development of treatment strategy for gastric cancer.

Inhibition of Lung Cancer Proliferation by Wogonin is Associated with Activation of Apoptosis and Generation of Reactive Oxygen Species

Background

Lung cancer has a very high incidence rate and is one of the commonly diagnosed tumors in developed countries.

Aims

To investigate the effect of wogonin on A549 and A427 lung cancer cells and explore the mechanism involved.

Study Design

Cell study.

Methods

The cytotoxicity effect of wogonin on A549 and A427 lung cancer and BEAS-2B cells was assessed by MTT assay. The onset of apoptosis was assessed by flow cytometry using Annexin V FITC/PI staining. Western blotting was used for the determination of changes in apoptotic protein expression.

Results

Wogonin treatment exhibited cytotoxicity effect selectively on A549 and A427 cells without affecting BEAS-2B normal lung cells. The viability of A549 and A427 cells was reduced to 31% and 34%, respectively, on treatment with 50 μM of wogonin; however, there was no significant reduction in BEAS-2B cell viability on treatment with the same concentration of it. Moreover, the percentage of apoptotic A427 cells showed a significant (p<0.049) increase on treatment with wogonin. Furthermore, the treatment led to a marked increase in the activation of caspase 3/8/9 and the generation of reactive oxygen species (ROS) at 72 h in A427 cells. Digital tomosynthesis studies showed a marked reduction in tumor development on treatment with wogonin.

Conclusion

Wogonin treatment specifically exhibits a cytotoxic effect on lung cancer cells and this effect is associated with activation of apoptosis and generation of reactive oxygen species.

Inhibition of Proliferation of SGC7901 and BGC823 Human Gastric Cancer Cells by Ursolic Acid Occurs Through a Caspase-Dependent Apoptotic Pathway

BACKGROUND Worldwide, gastric cancer is one of the most common malignant tumors. Ursolic acid is a plant metabolite and pentacyclic triterpenoid used in traditional Chinese medicine. This study aimed to investigate the effects of ursolic acid the growth and apoptosis of SGC7901 and BGC823 human gastric cancer cells in vitro. MATERIAL AND METHODS SGC7901 and BGC823 human gastric cancer cells and normal GES-1 gastric epithelial cells were cultured with increasing doses of ursolic acid at 50, 60, and 100 µM. Cell viability and proliferation were assessed using an MTT assay. Flow cytometry was used to assess cell apoptosis. Western blot was used to measure procaspase-8, procaspase-9, procaspase-3, and cleaved poly (ADP-ribose) polymerase (PARP) expression. The expression of receptor interaction protein 3 (RIP3) was examined by Western blot and reverse transcription polymerase chain reaction (RT-PCR). Morphological changes in the gastric cancer cells were determined using Hoechst 33342 staining following ursolic acid treatment. RESULTS Ursolic acid inhibited the viability of SGC7901 and BGC823 cells but not GES-1 cells. Ursolic acid treatment significantly induced apoptosis in SGC7901 and BGC823 cells when compared with GES-1 cells (P<0.05), and significantly increased the activation of caspase-3, caspase-8, caspase-9, poly ADPribose polymerase (PARP), and the production of reactive oxygen species (ROS). Treatment of SGC7901 and BGC823 cells with ursolic acid for 72 h did not induce necroptosis. CONCLUSIONS Ursolic acid inhibited the proliferation of SGC7901 and BGC823 human gastric cancer cells in vitro through a caspase-dependent apoptotic pathway.

Sono and photo stimulated Chlorine E6 nanocomposite in tumor-bearing mice: upcoming cancer treatment

This study was directed at study the effectiveness of cancer targeted therapy using the activated Chlorine E6 nanocomposite (Nano-CE6). Study was applied on male Swiss albino mice, implanted with Ehrlich tumor (EAC) divided into six groups. Two energy sources were used; laser and Ultrasound. Results showed that Nano-CE6 is a potential sensitizer for photodynamic or sonodynamic treatment of tumor. Nano-CE6 plays an important role in tumor growth inhibition and cell death induction. Activated Nano-CE6 with both infrared laser and ultrasound has a potential antitumor effect. The results indicated that (FA–NGO–CE6) could be used as a unique nanocomposite for cancer targeted therapy SPDT.

Sinoporphyrin sodium based sonodynamic therapy induces anti-tumor effects in hepatocellular carcinoma and activates p53/caspase 3 axis

Sonodynamic therapy (SDT) is a noninvasive therapeutic method via the activation of certain chemical sensitizers using low intensity ultrasound. In this work, we evaluated the antitumor effect of sinoporphyrin sodium (DVDMS) mediated SDT (DVDMS-SDT) on Hepatocellular carcinoma (HCC) cell lines both in vitro and in vivo. The results indicated that DVDMS-SDT was significantly more efficacious than PpIX-SDT in treating hepatocellular cell line Hep-G2. DVDMS-SDT also increased the ratio of cells in the G2/M phase and decreased the CDK1 and Cyclin B1 protein level. DVDMS-SDT markedly increased intracellular reactive oxygen species (ROS) in vitro. The increased ROS production up-regulated the expression of p53 and Bax, and down-regulated Bcl-2 expression, which led to the activation of caspase-3, ultimately initiated cell apoptosis. These effects could be partially reversed by the ROS scavenger N-acetylcysteine (NAC). In vivo experiments revealed that the DVDMS-SDT resulted in an effective inhibition of tumor growth and prolonged the survival time of tumor-bearing mice. More importantly, no obvious signs of side effects were observed. These results suggested that DVDMS-SDT is very effective in treating Hepatocellular carcinoma without side effects. The primary mechanism of SDT is due to the increased ROS activated the p53/Caspase 3 axis of apoptosis.

Corilagin induces apoptosis, autophagy and ROS generation in gastric cancer cells in vitro

Corilagin, a unique component of the tannin family, has been identified in several medicinal plants. In previous literature, corilagin exhibited a marked anticancer property in a variety of human cancer cells. However, the biological effects of corilagin on gastric cancer and the mechanisms involved remain to be fully elucidated. In the present study, it was reported that corilagin induced inhibition of cell growth in SGC7901 and BGC823 cells in a concentration-dependent manner. It was found that corilagin exhibited less toxicity towards normal GES-1 cells. Furthermore, the study showed that corilagin induced the apoptosis of gastric cancer cells mainly via activating caspase-8, -9, -3 and poly ADP-ribose polymerase proteins. Simultaneously, it was verified that corilagin triggered autophagy in gastric cancer cells and the inhibition of autophagy improved the activity of corilagin on cell growth suppression. In addition, corilagin significantly increased intracellular reactive oxygen species production, which is important in inhibiting the growth of gastric cancer cells. Finally, it was shown that necroptosis cannot be induced by corilagin-incubation in SGC7901 and BGC823 cell lines. Consequently, these findings indicate that corilagin may be developed as a potential therapeutic drug for gastric cancer.

Sonodynamic therapy: A potential treatment for atherosclerosis

Atherosclerosis (AS), a chronic arterial disease, is one of the major causes of morbidity and mortality worldwide. Several treatment modalities have been demonstrated to be effective in treating AS; however, the mortality rate due to AS remains high. Sonodynamic therapy (SDT) is a promising new treatment using low-intensity ultrasound in combination with sonosensitizers. Although SDT was developed from photodynamic therapy (PDT), it has a stronger tissue-penetrating capability and exhibits a more focused effect on the target lesional site requiring treatment. Furthermore, SDT has been demonstrated to suppress the formation of atheromatous plaques, and it can increase plaque stability both in vitro and in vivo. In this article, we critically summarize the recent literature on SDT, focusing on its possible mechanism of action as well as the existing and newly discovered sonosensitizers and chemotherapeutic agents for the treatment of AS.

20(S)-Ginsenoside Rh2 Induce the Apoptosis and Autophagy in U937 and K562 Cells

Acute myeloid leukemia (AML) and Chronic myelogenous leukemia (CML) are common leukemia in adults. 20(S)-GRh2 is an important bioactive substance that is present in Panax ginseng. However, there are no investigations that deal with the comparison of apoptosis, the occurrence of autophagy, and the relationship between apoptosis and autophagy after being treated with 20(S)-GRh2 in AML and CML. In this study, we explored the effect of 20(S)-GRh2 on the AML and CML (U937 and K562). Fluorescence microscopy, CCK-8, Quantitative realtime PCR, Western blot, transmission electron microscopy (TEM), and flow cytometric analysis were used to detect the occurrence of cell proliferation inhibition, apoptosis, and autophagy. By using the above methods, it was determined that apoptosis induced by 20(S)-GRh2 was more obvious in K562 than U937 cells and 20(S)-GRh2 could generate autophagy in K562 and U937 cells. When pretreated by a specific inhibitor of autophagy, (3-methyladenine), the 20(S)-GRh2-induced apoptosis was enhanced, which indicated that 20(S)-GRh2-induced autophagy may protect U937 and K562 cells from undergoing apoptotic cell death. On the other hand, pretreated by an apoptosis suppressor (Z-VAD-FMK), it greatly induced the autophagy and partially prevented 20(S)-GRh2 induced apoptosis. This phenomenon indicated that 20(S)-GRh2-induced autophagy may serve as a survival mechanism and apoptosis and autophagy could act as partners to induce cell death in a cooperative manner. These findings may provide a rationale for future clinical application by using 20(S)-GRh2 combined autophagy inhibitors for AML and CML.

Efficacy of Indocyanine Green-Mediated Sonodynamic Therapy on Rheumatoid Arthritis Fibroblast-like Synoviocytes

Sonodynamic therapy (SDT) has become a new therapeutic method because of its activation of certain sensitizers by ultrasound. Some studies have reported that indocyanine green (ICG) has the characteristics of a sonosensitizer and favorable fluorescence imaging in synovitis of early inflammatory arthritis. In this study, we aimed to investigate the cytotoxic effect of ICG-mediated SDT on MH7A cells in vitro and the potential mechanisms involved. ICG was found to be taken up mainly in cytoplasm, with maximal uptake in 4 h. Cell viability in ICG-mediated SDT (SDT-0.5 and SDT-1.0) groups decreased significantly to 73.09 ± 1.97% and 54.24 ± 4.66%, respectively; cell apoptosis increased significantly to 26.43 ± 0.91% and 45.93 ± 6.17%, respectively. Moreover, marked loss in mitochondrial membrane potential and greatly increased generation of reactive oxygen species were observed in ICG-mediated SDT groups. Interestingly, the loss in cell viability could be effectively rescued with pretreatment with the reactive oxygen species scavenger N-acetylcysteine. These results indicate that ICG-mediated SDT is cytotoxic to fibroblast-like synoviocytes and is a potential modality for targeted therapy of synovitis in rheumatoid arthritis.

Spinosad induces autophagy of Spodoptera frugiperda Sf9 cells and the activation of AMPK/mTOR signaling pathway

Spinosad, a high-selectivity neural toxin, has been widely used in agricultural production. However, the mode of action of spinosad on insect non-neural cells is not yet clear and hence requires further investigation. Therefore, to reveal the cytotoxic mechanisms of spinosad, we investigated whether and how it can induce autophagic cell death. After treating Sf9 cells with spinosad, the resulting autophagosome was observed by transmission electron microscopy and monodansylcadaverine staining. Interestingly, spinosad induced the accumulation of Beclin-1, degradation of p62, and intensification of LC3-B formation and translocation and thus autophagy, whereas, 3-MA treatment reverted the phenotype. Under ATP depletion conditions, spinosad induced autophagy of Sf9 cells and activation of the AMPK/mTOR signaling pathway.

Berberine-sonodynamic therapy induces autophagy and lipid unloading in macrophage

Impaired autophagy in macrophages accompanies the progression of atherosclerosis and contributes to lipid loading in plaques and ineffective lipid degradation. Therefore, evoking autophagy and its associated cholesterol efflux may provide a therapeutic treatment for atherosclerosis. In the present study, berberine-mediated sonodynamic therapy (BBR-SDT) was used to induce autophagy and cholesterol efflux in THP-1 macrophages and derived foam cells. Following BBR-SDT, autophagy was increased in the macrophages, autophagy resistance in the foam cells was prevented, and cholesterol efflux was induced. The first two effects were blocked by the reactive oxygen species scavenger, N-acetyl cysteine. BBR-SDT also reduced the phosphorylation of Akt and mTOR, two key molecules in the PI3K/AKT/mTOR signaling pathway, which is responsible for inducing autophagy. Correspondingly, treatment with the autophagy inhibitor, 3-methyladenine, or the PI3K inhibitor, LY294002, abolished the autophagy-induced effects of BBR-SDT. Furthermore, induction of cholesterol efflux by BBR-SDT was reversed by an inhibition of autophagy by 3-methyladenine or by a small interfering RNA targeting Atg5. Taken together, these results demonstrate that BBR-SDT effectively promotes cholesterol efflux by increasing reactive oxygen species generation, and this subsequently induces autophagy via the PI3K/AKT/mTOR signaling pathway in both ‘normal' macrophages and lipid-loaded macrophages (foam cells). Thus, BBR-SDT may be a promising atheroprotective therapy to inhibit the progression of atherosclerosis and should be further studied.

ROS-Dependent Activation of Autophagy through the PI3K/Akt/mTOR Pathway Is Induced by Hydroxysafflor Yellow A-Sonodynamic Therapy in THP-1 Macrophages

Monocyte-derived macrophages participate in infaust inflammatory responses by secreting various types of proinflammatory factors, resulting in further inflammatory reactions in atherosclerotic plaques. Autophagy plays an important role in inhibiting inflammation; thus, increasing autophagy may be a therapeutic strategy for atherosclerosis. In the present study, hydroxysafflor yellow A-mediated sonodynamic therapy was used to induce autophagy and inhibit inflammation in THP-1 macrophages. Following hydroxysafflor yellow A-mediated sonodynamic therapy, autophagy was induced as shown by the conversion of LC3-II/LC3-I, increased expression of beclin 1, degradation of p62, and the formation of autophagic vacuoles. In addition, inflammatory factors were inhibited. These effects were blocked by Atg5 siRNA, the autophagy inhibitor 3-methyladenine, and the reactive oxygen species scavenger N-acetyl cysteine. Moreover, AKT phosphorylation at Ser473 and mTOR phosphorylation at Ser2448 decreased significantly after HSYA-SDT. These effects were inhibited by the PI3K inhibitor LY294002, the AKT inhibitor triciribine, the mTOR inhibitor rapamycin, mTOR siRNA, and N-acetyl cysteine. Our results demonstrate that HSYA-SDT induces an autophagic response via the PI3K/Akt/mTOR signaling pathway and inhibits inflammation by reactive oxygen species in THP-1 macrophages.

Hypericin-mediated sonodynamic therapy induces autophagy and decreases lipids in THP-1 macrophage by promoting ROS-dependent nuclear translocation of TFEB

Lipid catabolism disorder is the primary cause of atherosclerosis. Transcription factor EB (TFEB) prevents atherosclerosis by activating macrophage autophagy to promote lipid degradation. Hypericin-mediated sonodynamic therapy (HY-SDT) has been proved non-invasively inducing THP-1-derived macrophage apoptosis; however, it is unknown whether macrophage autophagy could be triggered by HY-SDT to influence cellular lipid catabolism via regulating TFEB. Here, we report that HY-SDT resulted in the time-dependent THP-1-derived macrophage autophagy activation through AMPK/AKT/mTOR pathway. Besides, TFEB nuclear translocation in macrophage was triggered by HY-SDT to promote autophagy activation and lysosome regeneration which enhanced lipid degradation in response to atherogenic lipid stressors. Moreover, following HY-SDT, the ABCA1 expression level was increased to promote lipid efflux in macrophage, and the expression levels of CD36 and SR-A were decreased to inhibit lipid uptake, both of which were prevented by TFEB knockdown. These results indicated that TFEB nuclear translocation activated by HY-SDT was not only the key regulator of autophagy activation and lysosome regeneration in macrophage to promote lipolysis, but also had a crucial role in reverse cholesterol transporters to decrease lipid uptake and increase lipid efflux. Reactive oxygen species (ROS) were adequately generated in macrophage by HY-SDT. Further, ROS scavenger N-acetyl-l-cysteine abolished HY-SDT-induced TFEB nuclear translocation and autophagy activation, implying that ROS were the primary upstream factors responsible for these effects during HY-SDT. In summary, our data indicate that HY-SDT decreases lipid content in macrophage by promoting ROS-dependent nuclear translocation of TFEB to influence consequent autophagy activation and cholesterol transporters. Thus, HY-SDT may be beneficial for atherosclerosis via TFEB regulation to ameliorate lipid overload in atherosclerotic plaques.

Inhibition of autophagy promotes apoptosis and enhances anticancer efficacy of adriamycin via augmented ROS generation in prostate cancer cells

The interplay between autophagy and apoptosis response to chemotherapy is still a subject of intense debate in recent years. More efforts have focused on the regulation effects of apoptosis on autophagy, whereas how autophagy affects apoptosis remains poorly understood. In this study performed on prostate cancer cells, we investigated the role of autophagy in adriamycin-induced apoptosis, as well as the mechanisms mediating the effects of autophagy on apoptosis response to adriamycin (ADM). The results show that ADM not only inhibited cell viability and enhanced apoptosis, but also promoted autophagy via PI3K/Akt(T308)/mTOR signal pathway. Inhibition of autophagy by either pharmacological inhibitor chloroquine (CQ) or RNA interference of Atg5 increased ADM-induced apoptosis and enhanced the chemosensitivity of prostate cancer cells. Moreover, blockade of autophagy augmented reactive oxygen species (ROS) generation induced by ADM. Scavenging of ROS by antioxidant N-acetyl-cysteine (NAC) reversed the strengthened effects of CQ on ADM-induced apoptosis and rescued the cells from apoptosis. The results identified ROS as a potential mediator directing the modulation effects of the protective autophagy on apoptosis response to ADM. Suppression of the protective autophagy might provide a promising strategy to increase the anticancer efficacy of agents in the treatment of prostate cancer.

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.

Polytrichum commune L.ex Hedw ethyl acetate extract-triggered perturbations in intracellular Ca²⁺ homeostasis regulates mitochondrial-dependent apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Polytrichum commune L.ex Hedw (PCLH), a moss of Bryopsida, has been used as a traditional Chinese medicine and shown to possess anticancer activities. Previous studies have indicated its anti-leukemia effect but the potential mechanisms have not been fully explained.

AIM OF THE STUDY

The present study aimed to further investigate the efficacy of PCLH ethyl acetate fraction (PC-EEF) and the associated mechanisms in human leukemia cells.

MATERIALS AND METHODS

Phytochemical analysis of PC-EEF was performed by spectrophotometry and HPLC. MTT analysis and trypan blue exclusion assay were adopted to examine its cytotoxicity on a panel of leukemia cells (K562, U937, HL-60 and K562/DOX cells) and non-cancerous cells (human PBMCs). Anti-proliferative effect was monitored by colony formation assay and EdU incorporation assay. Ultrastructural alterations on K562 cell membrane surface were observed by scanning electron microscopy. Changes on plasma membrane integrity, cell membrane potential, mitochondrial membrane potential and apoptosis were analyzed by flow cytometry. Fluorescence microscope was performed to assess [Ca(2+)]i level, mitochondrial injury and cytochrome c release. Apoptosis-associated protein expression was analyzed by western blot. The role of Ca(2+) in PC-EEF-induced cell death was investigated by Ca(2+) chelating reagent BAPTA-AM.

RESULTS

PC-EEF possessed relatively high flavonoid content (about 88.84 ± 0.89%) and showed significant cytotoxicity to human leukemia cells. PC-EEF could cause obvious cell morphological deformation, membrane integrity loss and membrane depolarization. Meanwhile, PC-EEF treatment could dramatically potentiate perturbations in cellular Ca(2+) homeostasis. Subsequently, mitochondrial membrane potential (MMP) collapse, cytochrome c release and Bcl-2/Bax down-regulation were all observed. Consistent with these results, PC-EEF treatment resulted in significant activation of caspase 3, poly (ADP-ribose) polymerase (PARP) degradation and apoptosis. Moreover, PC-EEF-caused cytotoxicity, membrane damage, mitochondrial injury and apoptosis were remarkably reversed by BAPTA-AM.

CONCLUSIONS

PC-EEF damaged the membrane system and triggered Ca(2+)-dependent mitochondrial apoptosis, which may provide some new insights into its efficacy against human leukemia cells.