Low-frequency ultrasound combined with microbubbles improves gene transfection in prostate cancer cells in vitro and in vivo.

OBJECTIVES: The aim of this study is to explore whether low-frequency ultrasound combined with microbubbles improves pEGFP genes transfection into human prostate cancer cells. METHODS: Ultrasound with frequency of 80 kHz and duty cycle of 50% was adopted in the study; in in vitro experiments, cell lysis, and membrane damage were evaluated after ultrasound exposure; and the membrane continuity and transfection efficiency were observed by transmission electron microscope and laser scanner, respectively. Human prostate cancer xenograft models were exposed to ultrasound and transfection efficiency and histological examination were analyzed. RESULTS: Compared with the control group, ultrasound combined with microbubbles significantly improves gene transfection efficiency (P < .05). In in vitro study, ultrasound combined with microbubbles resulted in cell lysis and the interruption of cell membrane continuity, and its average transfection efficiency was 9.9%; the green fluorescence intensity was 15.2% in the ultrasound combined with microbubbles group in vivo; both values were higher than that in the control group (P < .05). CONCLUSION: Low-frequency ultrasound combined with microbubbles could be used as a method to promote gene transfection in prostate cancer cells.

Delivery of CD151 by Ultrasound Microbubbles in Rabbit Myocardial Infarction.

OBJECTIVES: We aimed to evaluate whether ultrasound (US) and microbubble-mediated delivery of Cluster of Differentiation 151 (CD151) could enhance the therapeutic effects of CD151 on myocardial infarction (MI). METHODS: A rabbit model of MI was established by a modified Fujita method. Then, 50 MI rabbits were randomly divided into 5 groups, including G1 (CD151 plasmid and physiological saline in the presence of US); G2 (CD151 and Sonovue in the presence of US); G3 (CD151 and Sonovue in the absence of US); G4 (Sonovue in the absence of US), and a control group (physiological saline in the absence of US). After 14 days of treatment, the expression of CD151 was detected by Western blot. Besides, vessel density of peri-infarcted myocardium was measured by immunohistochemistry, and cardiac function was analyzed by echocardiography. RESULTS: The rabbit model of MI was established successfully. CD151 injection increased the expression of CD151 and microvessel density in the myocardium of MI rabbits. Heart function was significantly improved by CD151, which exhibited increased left ventricular ejection fraction, left ventricular fractional shortening and a reduced Tei index. Besides, US Sonovue significantly increased the expression efficiency of CD151. CONCLUSION: US microbubble was an effective vector for CD151 delivery. CD151 might be an effective therapeutic target for MI.

Low-frequency ultrasound-mediated microvessel disruption combined with docetaxel to treat prostate carcinoma xenografts in nude mice: A novel type of chemoembolization.

The aim of the present study was to investigate whether low-frequency ultrasound (US)-mediated microvessel disruption combined with docetaxel (DTX) can be used as a novel type of chemoembolization. Mice were assigned to four groups: i) The USMB group, treated with low-frequency US combined with microbubbles (USMB); ii) the DTX group, treated with DTX; iii) the USMB + DTX group, treated with combined therapy; and iv) the control group, which was untreated. Immediately after the first treatment, the average peak intensity (API) on contrast-enhanced US was calculated, and tumors were excised for hematoxylin and eosin (HE) staining. At 2 weeks post-treatment, the tumor volumes and wet weights were calculated, and tumors were excised for immunohistochemistry to calculate apoptotic index (AI), proliferative index (PI) and microvessel density (MVD) values. Immediately after the first treatment, in the DTX and control groups, the tumors demonstrated abundant perfusion enhancement, while in the USMB + DTX and USMB groups, blood perfusion of the tumors was interrupted. Compared with that of the control group, the API was significantly lower in the USMB + DTX USMB groups (all P<0.001). HE staining showed that tumor microvasculature was disrupted into flaky hematomas and severely dilated microvessels in the USMB + DTX and USMB groups. In the DTX and control groups, there was no distinct evidence of the disruption and dilation of blood microvessels. At the end of the treatment, the mean tumor inhibition ratio was 73.33, 46.67 and 33.33% for the USMB + DTX, DTX and USMB groups, respectively. The USMB + DTX group had the highest AI, and the lowest PI and MVD compared with the other groups, although the difference between the USMB + DTX and DTX groups with regard to PI and MVD was not significant (USMB + DTX vs. DTX group, P=0.345 and P=0.059, respectively). In conclusion, as a novel type of chemoembolization, USMB combined with DTX is more effective than USMB or DTX alone in inhibiting tumor growth via the enhancement of apoptosis, and the suppression of proliferation and angiogenesis.

[MicroRNA-182 modulates high glucose-induced cardiomyocyte hypertrophy via targeting Rac1].

OBJECTIVE: To investigate the role and signalling of microRNA(miR)-182 on regulating high glucose-induced cardiomyocyte hypertrophy. METHODS: The candidates of miR which might potentially be involved on targeting Rac1 were predicted by applying bioinformatics analysis. The expression of all related candidates miRs was verified by real-time reverse transcription-PCR (RT-PCR) in cardiac tissues of db/db mice and db/m mice. Then the relationship between candidates miR and Rac1 was investigated with Pearson relevant analysis. Neonatal mice cardiomyocytes were cultured and divided into 2 groups: normal glucose group and high glucose group. The level of selected miR and Rac1 in two groups was detected by RT-PCR. Neonatal mice cardiomyocytes were then randomly divided into 4 groups: normal glucose group, selected microRNA mimics control group, high glucose group, high glucose plus selected miR mimics control group. The morphology of cardiomyocyte in each group was detected under light microscope. Furthermore, Rac1, ß-MHC and α-SMA expressions were detected in cultured cardiomyocyte treated by high glucose for 48 h after transfecting selected miR mimics by RT-PCR and Western blot. RESULTS: A total of 6 miR candidates potentially targeting Rac1 were screened by bioinformatics, which were miR-182, miR-142-3p, miR-140, miR-101a, miR-429 and miR-200b. Among these candidates, miR-182 and miR-142-3p expression was significantly downregulated in cardiac tissues of db/db mice compared with db/m controls (P < 0.05). MiR-182 was negatively correlated with Rac1 by person analysis (r = -0.891 02). Downregulation of miR-182 and upregulation of Rac1, ß-MHC, α-SMA were found in high glucose-induced cardiomyocyte. After transfection of miR-182 mimics, hypertrophic changes were significantly reduced and Rac1 as well ß-MHC expression was significantly downregulated in cardiomyocyte incubated with high glucose. CONCLUSION: MiR-182 might be involved in the regulation of high glucose-induced myocardial hypertrophy process via targeting Rac1.

Caveolin-1 as a biomarker to predict therapeutic effect of low-frequency ultrasound combined with SonoVue on prostate cancer in nude mice model.

BACKGROUND: Caveolin-1 is a major structural component of cell membrane invaginations. Over-expression of caveolin-1 is closely related to the tumorigenesis and progression of prostate cancer. Recently, contrast microbubbles in combination with ultrasound are being investigated for their therapeutic applications in tumor cells. However, the response of caveolin-1 after low-frequency ultrasound and SonoVue treatment in animal model is unclear. OBJECTIVE: The goal of this study was to evaluate the effect of 80 kHz ultrasound and/or SonoVue on caveolin-1 expression and secretion in DU145 prostate tumors in nude mice. METHODS: Six-week-old BALB/c male nude mice were subcutaneously injected with DU145 cells in the right flank to establish a prostate cancer model, which were randomly divided into four groups (n=8 each): control group (sham-ultrasound exposure), SonoVue group, 80 kHz ultrasound group, 80 kHz ultrasound combined with SonoVue group. Tumor volumes and wet weights were measured, and the tumor volume curve was obtained as well. The mice were euthanized 21 days after treatment. Specimens of the tumor tissues were assessed the expression of caveolin-1 by immunohistochemistry and Western blot. The serum concentrations of caveolin-1 were detected by ELISA. RESULTS: Treatment with ultrasound alone produced tumor volumes and weights reduction compared with control and SonoVue group. Combined ultrasound and SonoVue treatment produced greater tumor regression than either treatment alone (p < 0.05). Serum caveolin-1 concentrations were lower in the combination of ultrasound and SonoVue group than they were in control group (p =0.005), and had some certain correlation with tumor growth (wet weight) (r =0.507), although the difference was not statistically significant (p=0.199). Ultrasound alone treatment only slightly reduced the caveolin-1 concentrations in comparison with the control, and the difference was not statistically significant (p=0.125). The ultrasound-treated mice showed significant reduction in expression levels of caveolin-1 protein, compared with the control (p < 0.05). Levels of caveolin-1 were further reduced when combined with ultrasound and SonoVue as compared to the control (p < 0.01). CONCLUSIONS: Our results suggest that 80 kHz ultrasound have antitumor effect and the effect could be further strengthened by the combination of SonoVue. Down-regulating the expression of caveolin-1 is likely a potential biomarker of response to ultrasound and SonoVue treatment in prostate cancer mouse model.

Inhibitory effects of subcutaneous tumors in nude mice mediated by low-frequency ultrasound and microbubbles.

The aim of the present study was to investigate the sonication effects of 21-kHz ultrasound (US) with microbubbles (MBs) on the subcutaneous prostate tumors of nude mice. In total, 15 tumor-bearing nude mice were divided into three groups: The control group, the low-frequency US group and the US+MB group. The MBs used were from US contrast agent SonoVue. The parameters of the US were as follows: 21 kHz, 26 mW/cm2 and a 40% duty cycle (2 sec on, 3 sec off) for 3 min, once every other day for 2 weeks. Color Doppler flow imaging, hematoxylin and eosin (HE) staining, immunoblotting and transmission electron microscopy (TEM) were used to evaluate the results. Following 2 weeks of treatment, the blood flow signal disappeared in the US+MB group only, and the tumor size was smaller when compared with the control and US groups. For the immunoblotting, the intensity of cyclooxygenase-2 and vascular endothelial growth factor in the US+MB group was lower compared with the other two groups. Tumor necrosis was present and the nucleus disappeared upon HE staining in the US+MB group. Upon TEM analysis, increased cytoplasmic vacuolation and dilatation of the perinuclear cisternae of the tumor cells were found in the US+MB group. In the control and US groups, the tumors had intact vascular endothelia and vessel lumens. However, lumen occlusion of the vessels was observed in the US+MB group. In conclusion, 21-kHz low-intensity US with MBs may result in vessel occlusion and growth inhibitory effects in the subcutaneous tumors of nude mice.

Effects of low-frequency ultrasound combined with microbubbles on benign prostate hyperplasia.

INTRODUCTION: Our objective is to assess the effects of low-frequency ultrasound combined with microbubbles on benign prostate hyperplasia (BPH). METHODS: Sixteen Beagle dogs with BPH were randomly assigned into 4 groups (n = 4): control group (without treatment), G1 group (injection with 2 mL of microbubble contrast agent); G2 group (21 kHz ultrasound); and G3 group (injection with 2 mL of micro-bubble contrast agent +21 kHz ultrasound). The histopathological damage to prostate cells was assessed via transmission electron microscopy and optical microscopy. The protein expressions of prostate-specific antigen (PSA), inducible nitric oxide synthase (iNOS), superoxide dismutase (SOD) of vessels were detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: Histopathologically, the prostate cells exhibited nuclear chromatin contraction, mitochondrial swelling, degranulation of rough endoplasmic reticulum, basement membrane rupture and cell apoptosis in the G2 and G3 groups; it was especially obvious in the G3 group, while no changes were observed in the control and G1 groups. Although prostate volume using imaging was not significantly changed in all groups after treatment, PSA was significantly reduced in the G2 and G3 groups, and especially obvious in the G3 group (p < 0.05). The iNOS and SOD, which are important oxidative stress factors, significantly increased after treatment in the G2 and G3 groups, but not in the control and G1 groups (p < 0.05). CONCLUSIONS: Low-frequency ultrasound is effective in treating BPH; low-frequency ultrasound combined with microbubbles improves the treatment efficacy.

Effects of low-frequency ultrasound and microbubbles on angiogenesis-associated proteins in subcutaneous tumors of nude mice.

It has been shown that 1 and 3 MHz low-intensity ultrasound was able to affect the fragile and leaky angiogenic blood vessels in a tumor. However, the biological effects of 21 kHz low-intensity ultrasound on tumors remain unclear. The aim of the present study was to explore the effects of 21 kHz ultrasound with microbubbles on the regulation of vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2) and apoptosis in subcutaneous prostate tumors in nude mice. The study included three parts, each with 20 tumor-bearing nude mice. Twenty nude mice were divided into four groups: control (sham treatment), microbubble ultrasound contrast agent (UCA), low-frequency ultrasound (US) and US+UCA groups. The UCA used was a microbubble contrast agent (SonoVue). The parameter of ultrasound: 21 kHz, an intensity of 26 mW/cm2, 40% duty cycle (on 2 sec, off 3 sec), 3 min, once every other day for 2 weeks. In the first study, all subcutaneous tumors were examined by contrast-enhanced ultrasonography (CEUS) at the initiation and completion of the experiments. Peak intensity (PI), time to peak intensity (TTP) and area under the curve (AUC) on the time intensity curve (TIC) were analyzed. In the second study, the intensity of VEGF and COX-2 protein expression in the vascular endothelium and cytoplasm was evaluated using immunohistochemistry and laser confocal microscopy. In the third study, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay was used for the evaluation of cell apoptosis in tumor tissues. The tumor cells and vasculature were examined by transmission electron microscopy (TEM). Only in the US+UCA group, PI and AUC decreased. The intensity of COX-2 and VEGF in the US+UCA group in immunohistochemical staining and laser confocal microscopy was lower compared to that of the other three groups. More cell apoptosis was found in the US+UCA group compared to the other 3 groups. In the control, UCA and US groups, the tumors had intact vascular endothelium and vessel lumens in TEM. However, lumen occlusion of vessels was observed in the US+UCA group. Twenty-one kHz low-intensity ultrasound with microbubbles may have anti-angiogenic effects on subcutaneous tumors in nude mice.