Experiment on enhancing antitumor effect of intravenous epirubicin hydrochloride by acoustic cavitation in situ combined with phospholipid-based microbubbles

Combined treatment with ultrasound-targeted microbubble destruction technique and NM-aFGF-loaded PEG-nanoliposomes protects against diabetic cardiomyopathy-induced oxidative stress by activating the AKT/GSK-3β1/Nrf-2 pathway

The present study sought to investigate the effect of non-mitogenic acidic fibroblast growth factor (NM-aFGF) loaded PEGylated nanoliposomes (NM-aFGF-PEG-lips) combined with the ultrasound-targeted microbubble destruction (UTMD) technique on modulating diabetic cardiomyopathy (DCM)and the mechanism involved. Animal studies showed that the diabetes mellitus (DM) group exhibited typical myocardial structural and functional changes of DCM. The indexes from the transthoracic echocardiography showed that the left ventricular function in the NM-aFGF-PEG-lips + UTMD group was significantly improved compared with the DM group. Histopathological observation further confirmed that the cardiomyocyte structural abnormalities and mitochondria ultrastructural changes were also significantly improved in the NM-aFGF-PEG-lips + UTMD group compared with DM group. The cardiac volume fraction (CVF) and apoptosis index in the NM-aFGF-PEG-lips + UTMD group decreased to 10.31 ± 0.76% and 2.16 ± 0.34, respectively, compared with those in the DM group (CVF = 21.4 ± 2.32, apoptosis index = 11.51 ± 1.24%). Moreover, we also found significantly increased superoxide dismutase (SOD) activity and glutathione peroxidase (GSH-Px) activity as well as clearly decreased lipid hydroperoxide levels and malondialdehyde (MDA) activity in the NM-aFGF-PEG-lips + UTMD group compared with those in the DM group (p < .05). Western blot analysis further revealed the highest level of NM-aFGF, p-AKT, p-GSK-3β1, Nrf-2, SOD2 and NQO1 in the NM-aFGF-PEG-lips + UTMD group. This study confirmed using PEGylated nanoliposomes combined with the UTMD technique can effectively deliver NM-aFGF to the cardiac tissue of diabetic rats. The NM-aFGF can then inhibit myocardial oxidative stress damage due to DM by activating the AKT/GSK/Nrf-2 signaling pathway, which ultimately improved the myocardial structural and functional lesions in diabetic rats.

Lipid bubbles combined with low-intensity ultrasound enhance the intratumoral accumulation and antitumor effect of pegylated liposomal doxorubicin in vivo

Pegylated liposomal doxorubicin (PLD) is a representative nanomedicine that has improved tumor selectivity and safety profile. However, the therapeutic superiority of PLD over conventional doxorubicin has been reported to be insignificant in clinical medicine. Combination treatment with microbubbles and ultrasound (US) is a promising strategy for enhancing the antitumor effects of chemotherapeutics by improving drug delivery. Recently, several preclinical studies have shown the drug delivery potential of lipid bubbles (LBs), newly developed monolayer microbubbles, in combination with low-intensity US (LIUS). This study aimed to elucidate whether the combined use of LBs and LIUS enhanced the intratumoral accumulation and antitumor effect of PLD in syngeneic mouse tumor models. Contrast-enhanced US imaging using LBs showed a significant decrease in contrast enhancement after LIUS, indicating that LIUS exposure induced the destruction of LBs in the tumor tissue. A quantitative evaluation revealed that the combined use of LBs and LIUS improved the intratumoral accumulation of PLD. Furthermore, tumor growth was inhibited by combined treatment with PLD, LBs, and LIUS. Therefore, the combined use of LBs and LIUS enhanced the antitumor effect of PLD by increasing its accumulation in the tumor tissue. In conclusion, the present study provides important evidence that the combination of LBs and LIUS is an effective method for enhancing the intratumoral delivery and antitumor effect of PLD in vivo.

Influence of tumor cell lines derived from different tissue on sonoporation efficiency under ultrasound microbubble treatment

To reveal the effect of tumor cell lines derived from different tissue on sonoporation efficiency under ultrasound microbubble (USMB) treatment, and meanwhile to determine the optimum parameter combination for each tumor cell line. Human breast tumor (MCF-7), ovarian tumor (A2780), liver tumor (Bel7402) and thyroid tumor (ARO) were exposed to ultrasound in the presence of SonoVue MBs. The major parameters for the designed experiments including MB concentration (A1:10%, A2:20%, A3:30%), sound intensity (B1:0.5, B2:1.0, B3:1.5W/cm²), irradiation time (C1:30, C2:60, C3:90s). An orthogonal array experimental design based on three levels L9 (3³) of the above three parameters was employed to optimize the sonoporation efficiency. MTT experiment was used to calculate cell survival rate. FD500 uptake assay and cytometry were performed to evaluate transference percentage. The optimum parameter combination for each tumor cell line was different (MCF-7: A3B1C1, A2780: A1B3C3, Bel7402: A2B3C2, ARO: A2B3C2). Under their own optimum parameter combination, four kinds of tumor cell line exhibited different optimum sonoporation efficiency (MCF-7: 55.05±5.29%; A2780: 45.62±7.35%; Bel7402: 39.37±4.11%; ARO: 53.37±3.94%). Multiple comparison with LSD-t test showed that the sonoporation efficiency between four kinds of cell line was statistically significant (P<0.05), with the exception of MCF-7 VS. ARO (P=0.487). Tumor cell lines derived from different tissue can impact the sonoporation efficiency, and optimizing the exposure parameters can safely and efficiently increase the cell membrane permeability.

Combination of coenzyme Q10-loaded liposomes with ultrasound targeted microbubbles destruction (UTMD) for early theranostics of diabetic nephropathy

Diabetic nephropathy (DN) is one of the most common and lethal microvascular complications of diabetes. This study aimed to explore whether coenzymeQ10 (CoQ10) as an antioxidant combined with ultrasound-targeted microbubble destruction (UTMD) could reverse the progress of early diabetic nephropathy (DN). CoQ10 has great potential to treat early DN. However, the clinical application of CoQ10 has been limited because of its low aqueous solubility and non-specific distribution. Therefore, CoQ10-loaded liposomes (CoQ10-lip) were prepared and combined with ultrasound microbubbles for the early theranostics of DN. CoQ10-lip exhibited a good round morphology with a diameter of 183±1.7nm and a negative zeta potential of -25.3mV, which was capable of prolonging the release of the encapsulated CoQ10. The early DN rat models were induced by streptozotocin (STZ) and confirmed by contrast-enhanced ultrasound (CEUS) and 24-h urinary albumin. After the administration of CoQ10-lip combined with the UTMD technique to rats with early DN, the morphology and function of the kidney were evaluated by ultrasonography, histological and molecular analyses. The renal hemodynamics were significantly improved, moreover, 24-h urinary protein, and oxidative stress indexes were modulated after treatment with CoQ10-lip+UTMD indicating recovery of renal function. An elevated level of Nphs2 protein and reduced caspase 3 level indicated the preservation of podocytes and inhibition of cell apoptosis after CoQ10-lip+UTMD treatment. The molecular mechanism was associated with the upregulation of Bcl-2 and the downregulation of Bax. Moreover, the combination of CoQ10-lip and ultrasound microbubbles demonstrated a better protective effect on the damaged kidney than the other groups (free CoQ10 or CoQ10-lip+/- UTMD). Conclusively, CoQ10-lip in combination with ultrasound microbubbles might be a potential strategy to reverse the progress of early DN.

Inhibitory effect of epirubicin-loaded lipid microbubbles with conjugated anti-ABCG2 antibody combined with therapeutic ultrasound on multiple myeloma cancer stem cells

Ultrasound-targeted microbubble destruction (UTMD) technique is thought to improve the chemotherapeutic agent delivery from microbubbles (MBs) in tumor tissues and reduce the side effects in non-tumor tissues. Multiple myeloma (MM) is a bone marrow cancer and remains to be an incurable disease. In this study, we used the UTMD technique to investigate the inhibitory effect of our developed novel reagent on MM cancer stem cells (CD138(-)CD34(-)MM CSCs) that are MM cells with CD138(-)CD34(-) phenotypes, responsible for MM-initiating potential, drug resistance and eventual relapse. The preparatory steps of novel reagent was first epirubicin (EPI)-loaded in the lipid MBs that was consisted of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000]-biotin, dipalmitoyl-phosphatidylglycerol and 25-NBD-cholesterol, then anti-ABCG2 monoclonal antibody (mAb) was conjugated onto the MB surface to form EPI-MBs+mAb. CD138(-)CD34(-)MM CSCs were isolated from human MM RPMI 8226 cell line by the magnetic associated cell sorting method. The results showed that the attenuated proliferation, migration and invasion ability, and increased apoptosis were observed when MM CSCs were incubated with a various agents. EPI-MBs+mAb combined with therapeutic ultrasound significantly promoted the MM CSC apoptosis compared with EPI, EPI-MBs alone or EPI-MBs+mAb without ultrasound exposure. These results suggest that the developed EPI-MBs+mAb combined with therapeutic ultrasound remarkably induced MM CSC apoptosis in vitro.

Sonochemotherapy: from bench to bedside

The combination of microbubbles and ultrasound has emerged as a promising method for local drug delivery. Microbubbles can be locally activated by a targeted ultrasound beam, which can result in several bio-effects. For drug delivery, microbubble-assisted ultrasound is used to increase vascular- and plasma membrane permeability for facilitating drug extravasation and the cellular uptake of drugs in the treated region, respectively. In the case of drug-loaded microbubbles, these two mechanisms can be combined with local release of the drug following destruction of the microbubble. The use of microbubble-assisted ultrasound to deliver chemotherapeutic agents is also referred to as sonochemotherapy. In this review, the basic principles of sonochemotherapy are discussed, including aspects such as the type of (drug-loaded) microbubbles used, the routes of administration used in vivo, ultrasound devices and parameters, treatment schedules and safety issues. Finally, the clinical translation of sonochemotherapy is discussed, including the first clinical study using sonochemotherapy.

A review of low-intensity ultrasound for cancer therapy

The literature describing the use of low-intensity ultrasound in four major areas of cancer therapy-sonodynamic therapy, ultrasound-mediated chemotherapy, ultrasound-mediated gene delivery and anti-vascular ultrasound therapy-was reviewed. Each technique consistently resulted in the death of cancer cells, and the bio-effects of ultrasound were attributed primarily to thermal actions and inertial cavitation. In each therapeutic modality, theranostic contrast agents composed of microbubbles played a role in both therapy and vascular imaging. The development of these agents is important as it establishes a therapeutic-diagnostic platform that can monitor the success of anti-cancer therapy. Little attention, however, has been given either to the direct assessment of the mechanisms underlying the observed bio-effects or to the viability of these therapies in naturally occurring cancers in larger mammals; if such investigations provided encouraging data, there could be prompt application of a therapy technique in the treatment of cancer patients.

Tumour-associated macrophages targeted transfection with NF-κB decoy/mannose-modified bubble lipoplexes inhibits tumour growth in tumour-bearing mice

Tumour-associated macrophages (TAM) exhibit an M2 phenotype that promotes tumour progression, and conversion of M2 TAM toward a tumouricidal M1 phenotype is a promising anti-cancer therapy. As NF-κB is a key regulator of macrophage polarization, we developed an in vivo TAM-targeting delivery system that combines mannose-modified bubble liposomes/NF-κB decoy complexes (Man-PEG bubble lipoplexes) and ultrasound (US) exposure. We investigated the effects of NF-κB decoy transfection on TAM phenotype in solid tumour-bearing mice. Post-transfection tumour growth and survival rates were also recorded. Th2 cytokine (IL-10) level in TAM was significantly lower by NF-κB decoy transfection using Man-PEG bubble lipoplexes and US exposure, while Th1 cytokine levels (IL-1β, TNF-α and IL-6) were significantly higher when compared with controls. In addition, mRNA levels of vascular endothelial growth factor, matrix metalloproteinase-9 and arginase were significantly lower in TAM post-NF-κB decoy transfection. Importantly, TAM-targeted NF-κB decoy transfection inhibited tumour growth and prolonged survival rates in mice. Therefore, TAM-targeted NF-κB decoy transfection using Man-PEG bubble lipoplexes and US exposure may be an effective approach for anti-cancer therapy based on TAM phenotypic conversion from M2 toward M1.

An experimental research into endostatin microbubble combined with focused ultrasound for anti-tumor angiogenesis in colon cancer

Objective: to evaluate the therapeutic effect of targeted endostatin-loaded microbubbles, combined with improved, focused, directional ultrasound radiation for inhibition of subcutaneous translocation in situ colon tumor angiogenesis in colon cancer.

Methods: 65 BALB/c nude mice with subcutaneous translocation in situ colon tumors were randomly divided into five groups. Group A was the control group, without any treatments. In Group B, the mouse was treated with ultrasonic radiation. In Group C, the mouse was treated with ultrasonic radiation combined with empty SonoVue microbubbles. In Group D, the mouse was treated with ultrasonic radiation combined with empty Targestar-SA microbubbles. In Group E, the mouse was treated with ultrasonic radiation combined with endostatin microbubbles. The tumor size was measured before and 1, 14, and 28 days after irradiation. The peak intensity (PI), regional blood volume (RBV) and regional blood flow (RBF) were recorded using contrast-enhanced ultrasound. The tumor tissue was removed for pathological examination; the tumor necrosis area and microvascular density (MVD) were evaluated by immunohistochemistry.

Results: Tumors in Groups C, D and E were significantly smaller than in Groups A and B at 28 days after irradiation, with Group E the smallest. PI, RBF and RBV of Groups C, D, and E were significantly decreased 28 days after radiation with Group E the lowest, and significantly lower than Groups A and B (all P < 0.05). The tumor tissue necrosis area of Group E was clearly greater while MVD was obviously lower than the other groups (all P < 0.01) at 28 days after treatment.

Conclusion: The targeted endostatin microbubbles, combined with focused, directional ultrasound radiation can damage tumor microvasculature of subcutaneous colon translocation in situ colon cancer, as well as inhibit the tumor angiogenesis.

A wogonin-loaded glycyrrhetinic acid-modified liposome for hepatic targeting with anti-tumor effects

Liver cancer has become one of the most common fatal cancers worldwide, with morbidity rates increasing each year. Wogonin (WG) is an attractive candidate for the development of new anti-cancer drugs. In this study, a novel glycyrrhetinic acid (GA)-modified WG liposome was developed for use in targeted anti-cancer therapy. Three types of WG preparations were investigated: free wogonin in solution (WG), passively targeted wogonin liposomes (WG-Lip) and GA-modified wogonin liposomes (GA-WG-Lip). The entrapment efficiency, size and zeta potential were measured. Cellular uptake, cytotoxicity, in vivo bio-distribution and anti-tumor efficacy were also investigated. Addition of GA to the liposomes did not diminish the high entrapment efficiency observed in the liposomes without GA. GA-WG-Lip showed the greatest uptake and had an IC50 value 1.46 times higher than that of WG-Lip. The GA-modified liposomes rapidly accumulated in the liver with a long retention time, and also displayed a better tumor inhibitory ratio than that of the unmodified liposomes. Overall, the data indicated that use of the GA-modified WG liposomes conferred improvements in bio-distribution, accumulation at the tumor and therapeutic efficacy, perhaps due to increased receptor-mediated uptake of liposomes by liver-targeted cells. Together, these data show that GA-WG-Lip is a promising means of targeted therapy for liver cancer.

Potential and problems in ultrasound-responsive drug delivery systems

Ultrasound is an important local stimulus for triggering drug release at the target tissue. Ultrasound-responsive drug delivery systems (URDDS) have become an important research focus in targeted therapy. URDDS include many different formulations, such as microbubbles, nanobubbles, nanodroplets, liposomes, emulsions, and micelles. Drugs that can be loaded into URDDS include small molecules, biomacromolecules, and inorganic substances. Fields of clinical application include anticancer therapy, treatment of ischemic myocardium, induction of an immune response, cartilage tissue engineering, transdermal drug delivery, treatment of Huntington’s disease, thrombolysis, and disruption of the blood–brain barrier. This review focuses on recent advances in URDDS, and discusses their formulations, clinical application, and problems, as well as a perspective on their potential use in the future.

Improving the cardio protective effect of aFGF in ischemic myocardium with ultrasound-mediated cavitation of heparin modified microbubbles: preliminary experiment

Ultrasound (US)-mediated cavitation of microbubbles has evolved into a new tool for organ-specific gene and drug delivery. This paper was to investigate the feasibility of acidic fibroblast growth factor (aFGF) intravenous delivery to the ischemic myocardium of rats by ultrasonic microbubbles modified with heparin. Heparin modified microbubbles (HMB) were prepared by the freeze-dried method. Acute myocardial infarction (AMI) model was established and the cardio protective effect of the aFGF combing with HMB (aFGF-HMB) under US-mediated cavitation technique was investigated. aFGF-HMB combined with US-mediated cavitation technique was examined by ECG. Ejection fraction (EF), fractional shortening (FS) and left ventricular diastolic diameter (LVDd) were measured to monitor the improvement of global myocardial contractile function. Myocardial tissue was stained with hematoxylin and eosine (HE) to evaluate the elaborate general morphology of the ischemic myocardium. From morphologic observation and echocardiography in rat heart, aFGF-HMB had suitable size distribution, physical stability and good acoustic resonance function. From AMI rat experiments, aFGF-HMB under US-mediated cavitation technique exerted aFGF cardio protective effect in ischemic myocardium. From histological evaluation, US-mediated cavitation of aFGF-HMB showed improvement of myocardial ischemia. With the visual imaging and US-triggered drug release advantages, US-mediated cavitation of aFGF-HMB might be developed as a novel technique for targeting delivery of aFGF into ischemic myocardium.

Using acoustic cavitation to enhance chemotherapy of DOX liposomes: experiment in vitro and in vivo

Experiments in vitro and in vivo were designed to investigate tumor growth inhibition of chemotherapeutics-loaded liposomes enhanced by acoustic cavitation. Doxorubicin-loaded liposomes (DOX liposomes) were used in experiments to investigate acoustic cavitation mediated effects on cell viability and chemotherapeutic function. The influence of lingering sensitive period after acoustic cavitation on tumor inhibition was also investigated. Animal experiment was carried out to verify the practicability of this technique in vivo. From experiment results, blank phospholipid-based microbubbles (PBM) combined with ultrasound (US) at intensity below 0.3 W/cm² could produce acoustic cavitation which maintained cell viability at high level. Compared with DOX solution, DOX liposomes combined with acoustic cavitation exerted effective tumor inhibition in vitro and in vivo. The lingering sensitive period after acoustic cavitation could also enhance the susceptibility of tumor to chemotherapeutic drugs. DOX liposomes could also exert certain tumor inhibition under preliminary acoustic cavitation. Acoustic cavitation could enhance the absorption efficiency of DOX liposomes, which could be used to reduce DOX adverse effect on normal organs in clinical chemotherapy.