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Purpose: The ultrasonically induced effect of rose bengal (RB) on isolated tumor cells was investigated.Methods: Sarcoma 180 cells were suspended in air-saturated phosphate-buffered saline and exposed to ultrasound in standing wave mode for up to 60 s in the presence and absence of RB. Cell viability was determined by the ability to exclude trypan blue.Results: The rate of inducing cell damage by ultrasound was enhanced two to three times with 160 microM RB. while no cell damage was observed with RB alone. This enhancement was significantly inhibited by histidine.Conclusions: Ultrasonically induced in vitro cell damage was significantly enhanced by RB. A sonochemical mechanism may be suggested since the enhancement was significantly inhibited by an active oxygen scavenger. [ABSTRACT FROM AUTHOR]

Background/aim: Sonodynamic cancer therapy is based on the preferential uptake and/or retention of a sonosensitizing drug (sonosensitizer) in tumor tissues and the subsequent activation of the drug by ultrasound irradiation. In the present study, we investigated the sonodynamically-induced antitumoral effect with functionalized carbon nanotubes, such as poly-ethylene glycol-modified carbon nanotubes (PEG-modified CNTs)., Materials and Methods: Antitumor effects were evaluated using histological observation and assessing tumor growth following sonodynamic exposure to PEG-modified CNTs., Results: The combined treatment of 100 μM PEG-modified CNT and ultrasound induced a 2-fold cytotoxicity. Sodium azide, which quenches singlet oxygen, significantly inhibited ultrasonication induced cell damage in the presence of PEG-modified CNTs. This suggests that singlet oxygen produced by the combined use of PEG-modified CNTs and ultrasound is involved in the induction of antitumoral effects. The destruction of tumor tissue was observed with the ultrasonic treatment in combination with PEG-modified CNTs, while neither the treatment with PEG-modified CNTs alone nor ultrasound alone caused any necrosis., Conclusion: These results indicate that PEG-modified CNT functions as a sonosensitizer and is effective for sonochemical treatment of solid tumors., (Copyright© 2020, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background: The ultraviolet A (UVA) spectrum mainly includes the region associated with the phototoxicity of fluoroquinolone antimicrobial agents. This study investigated apoptosis induced with UVA light and enoxacin in HL-60 cells., Materials and Methods: HL-60 cells were irradiated by UVA (1.1 mW/cm 2 ) for 20 min in the presence or absence of enoxacin. The induction of apoptosis was investigated by analysing cell morphology, flow cytometry of annexin V-positive cells, DNA ladder formation, and caspase-3 activation., Results: Significant induction of apoptosis, DNA fragmentation, and caspase-3 activation were observed in cells treated with both UVA and enoxacin. UVA-induced apoptosis was significantly suppressed when NaN3, a singlet oxygen scavenger, was present., Conclusion: Apoptosis was induced by the combination of UVA and enoxacin in HL-60 cells, and singlet oxygen appears to play an important role in photodynamically-induced apoptosis., (Copyright© 2019, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background/aim: Acetyl-CoA carboxylase (ACC) is a rate-limiting enzyme in fatty acid synthesis. In this study, we investigated the effect of ACC inhibition on survival of pancreatic cancer cells., Material and Methods: AsPC-1, BxPC-3 and PANC-1 were used as human pancreatic cancer cell lines. 5-(etradecyloxy)-2-furoic acid (TOFA) and bis-2-(5-phenylacetamido-1,2,4-thiadiazol-2-yl) ethyl sulfide (BPTES) were used as inhibitors of ACC and glutaminase (GLS) respectively. Apoptotic and live cells were distinguished by annexin-V staining. The activity of caspase-3 was evaluated by measuring the fluorescence intensity of the degradation product of the substrate, N-acetyl-Asp-Glu-Val-Asp-7-amido-4-trifluoromethylcoumarin., Results: TOFA increased the number of annexin V-positive cells and enhanced caspase-3 activity in AsPC-1 and BxPC-3, but not in PANC-1 cells. The number of PANC-1 cells increased after 48 h in Earle's balanced salt solution. Interestingly, proliferation of PANC-1 cells was drastically suppressed by glutamine deprivation, but not by inhibition of glycolysis. BPTES also induced cell death to the same extent as glutamine deprivation. In addition, TOFA induced cell death of PANC-1 cells, both in the presence of BPTES and with glutamine deprivation, suggesting that inhibition of glutaminolysis causes cell death and enhances the effect of TOFA in PANC-1 cells., Conclusion: These findings suggest that glutaminolysis is important for the survival of pancreatic cancer cells showing tolerance to nutrient starvation such as PANC-1 cells, and use of a combination of inhibitors of ACC and GLS may be a new strategy for treatment of pancreatic cancer., (Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Pancreatic cancer is one of the deadliest human cancers. In the current study, we investigated the possibility of a new treatment strategy using a combination of the new fluoroquinolone, enoxacin, and mild ultraviolet A (UVA) irradiation. Enoxacin with UVA irradiation increased the number of annexin V-positive (apoptotic) pancreatic cancer cells in time- and concentration-dependent manners, whereas alone neither had these effects. In addition, enoxacin with UVA irradiation induced cleavage of poly (ADP-ribose) polymerase in AsPC1 human pancreatic cancer cells. Moreover, the singlet oxygen scavengers, histidine and sodium azide, and the hydroxyl radical scavenger, mannitol, significantly suppressed apoptosis induced by enoxacin and UVA irradiation, respectively. These results suggest that UVA irradiation activates enoxacin, after which activated enoxacin induces apoptosis of AsPC1 cells through generation of reactive oxygen species. Therefore, the combination of enoxacin with mild UVA irradiation may be a useful method for treating pancreatic cancer., (Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Lomefloxacin (LFX) is a widely used fluoroquinolone antimicrobial agent that plays an important role in the treatment of human and animal infections; however, it has been reported to cause phototoxicity. In this study, we investigated the induction of apoptosis due to ultraviolet A (UVA) light in the presence and absence of LFX in HL-60 human promyelocytic leukemia cells. HL-60 cells were exposed to UVA at an intensity of 1.1 mW/cm 2 for 20 min in the presence and absence of LFX, and the induction of apoptosis was examined by analyzing cell morphology, DNA fragmentation, and caspase-3 activity. Cells treated with 100 μM LFX and UVA clearly showed membrane blebbing and cell shrinkage. The proportion of apoptotic cells was significantly higher in cells treated with both UVA and LFX than in those treated with UVA or LFX alone. In addition, DNA ladder formation and caspase-3 activation were observed in cells treated with both UVA and LFX. A significant reduction in the number of UVA-induced apoptotic cells and caspase-3 activation was observed when histidine was present, which suggested that photodynamically-generated singlet oxygen is an important mediator of apoptosis. These results indicate that the combination of UVA and LFX induces apoptosis in HL-60 cells., (Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Cancer cells tend to have a high requirement for lipids, including fatty acids, cholesterol and triglyceride, because of their rapid proliferative rate compared to normal cells. In this study, we investigated the effects of inhibition of lipid synthesis on the proliferation and viability of human pancreatic cancer cells. Of the inhibitors of lipid synthesis that were tested, 5-(tetradecyloxy)-2-furoic acid (TOFA), which is an inhibitor of acetyl-CoA carboxylase, and the fatty acid synthase (FAS) inhibitors cerulenin and irgasan, significantly suppressed the proliferation of MiaPaCa-2 and AsPC-1 cells. Treatment of MiaPaCa-2 cells with these inhibitors significantly increased the number of apoptotic cells. In addition, TOFA increased caspase-3 activity and induced cleavage of poly (ADP-ribose) polymerase in MiaPaCa-2 cells. Moreover, addition of palmitate to MiaPaCa-2 cells treated with TOFA rescued cells from apoptotic cell death. These results suggest that TOFA induces apoptosis via depletion of fatty acids and that, among the various aspects of lipid metabolism, inhibition of fatty acid synthesis may be a notable target for the treatment of human pancreatic cancer cells., (Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Ultrasound has been widely utilized for medical diagnosis and therapy due to its ability to penetrate deep-seated tissue with less attenuation of energy and minimal undesirable side-effects. Functionalized fullerenes, such as polyhydroxy fullerene (PHF), have attracted particular attention due to their water solubility and potential application in tumor imaging and therapy as carbon nanomaterials. The present study investigated sonodynamically-induced apoptosis using PHF. Cell suspensions were treated with 2-MHz continuous ultrasound in the presence of PHF for 3 min and apoptosis was assessed by cell morphology using confocal microscopy, fragmentation of DNA (ladder pattern after agarose-gel electrophoresis) and caspase-3 activation. Cells were ultrasound-irradiated from the bottom of the culture dishes under the following condition: frequency, 2 MHz; output power, 3 W/cm(2) Electron spin resonance was used to measure reactive oxygen species. The number of apoptotic cells after sonodynamic exposure (ultrasound and PHF) was significantly higher than produced from other treatments, such as ultrasound alone and PHF alone. Furthermore, DNA fragmentation, caspase-3 activation and enhanced 2,2,6,6-tetramethyl-4-piperidinyloxy (4oxoTEMPO) formation were observed in the sonodynamically-treated cells. Histidine, a well-known reactive oxygen scavenger, significantly inhibited sonodynamically-induced apoptosis, caspase-3 activation and 4oxoTEMPO formation. Sonodynamic therapy with PHF induced apoptosis that was characterized by a series of typical morphological features, such as shrinkage of the cell and fragmentation into membrane-bound apoptotic bodies, in HL-60 cells. The significant inhibition of sonodynamically-induced apoptosis, caspase-3 activation, and 4oxoTEMPO formation due to histidine and tryptophan suggests that reactive oxygen species, such as singlet oxygen, are involved in the sonodynamic induction of apoptosis. These findings indicate that PHF-mediated sonodynamic therapy can trigger caspase-dependent apoptosis and oxidative injury, thus possibly playing a vital role in apoptotic signaling cascades., (Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Background/aim: Sonodynamic cancer therapy is based on the preferential uptake and/or retention of a sonosensitizing drug (sonosensitizer) in tumor tissues and subsequent activation of the drug by ultrasound irradiation. In the present study, we investigated the participation of lipid peroxidation in the mechanism of the sonodynamically-induced antitumor effect with functionalized fullerenes, such as polyhydroxy fullerene (PHF., Materials and Methods: Ultrasonically-induced cell damage and lipid peroxidation with PHF were compared in the same in vitro insonation setup. Sarcoma 180 cells suspended in PBS were exposed to 2 MHz ultrasound in the presence and absence of PHF. Cell viability was determined by the Trypan Blue exclusion test. Lipid peroxidation in cell membranes was estimated by measuring the amount of malondialdehyde as the thiobarbituric acid-reactive-substances., Results: Significant enhancement of the rates of both ultrasonically-induced cell damage and lipid peroxidation was observed in the presence of PHF, both of which were positively correlated with PHF. The enhancement of cell damage and lipid peroxidation with PHF was suppressed by reactive oxygen scavengers such as histidine and tryptophan., Conclusion: The good correlation observed in the presence of PHF suggests that membrane lipid peroxidation is one of the important intermediary events in sonodynamically-induced cellular damage. The inhibitory effects of histidine and tryptophan also provide evidence that singlet oxygen plays an important role in PHF-mediated sonosensitization of membranes and that this moiety may be an important mediator of cell destruction in sonodynamic therapy associated with PHF and ultrasound., (Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Background: Functionalized fullerenes, such as polyhydroxy fullerenes (PHF), have attracted particular attention due to their water solubility and their potential application in tumor imaging and therapy as carbon nanomaterials. In this study, the sonodynamically-induced antitumor effect of PHF was investigated., Materials and Methods: Sonodynamically-induced antitumor effects of PHF in combination with ultrasound were investigated using isolated sarcoma 180 cells and solid tumor from colon 26 carcinoma cells., Results: The cell damage induced by sonication was enhanced by two-fold in the presence of 80 μM PHF. Histidine significantly inhibited this enhancement. This inhibitory effect suggests that the sonodynamically-induced antitumor effect was mediated by sonodynamically-generated reactive oxygen species. The combined treatment of ultrasonic exposure with PHF suppressed the growth of implanted colon 26 tumors. The destruction of tumor tissue was observed with the ultrasonic treatment in combination with PHF, while neither the treatment with PHF alone nor that with ultrasound alone caused necrosis., Conclusion: These results suggest that PHF is a potential sonosensitizer for sonodynamic treatment of solid tumors.

In this study, we investigated the induction of apoptosis by ultrasound in the presence of the novel porphyrin derivative DCPH-P-Na(I). HL-60 cells were exposed to ultrasound for up to 3 min in the presence and absence of DCPH-P-Na(I), and the induction of apoptosis was examined by analyzing cell morphology, DNA fragmentation, and caspase-3 activity. Reactive oxygen species were measured by means of ESR and spin trapping technique. Cells treated with 8 μM DCPH-P-Na(I) and ultrasound clearly showed membrane blebbing and cell shrinkage, whereas significant morphologic changes were not observed in cells exposed to either ultrasound or DCPH-P-Na(I) alone. Also, DNA ladder formation and caspase-3 activation were observed in cells treated with both ultrasound and DCPH-P-Na(I) but not in cells treated with ultrasound or DCPH-P-Na(I) alone. In addition, the combination of DCPH-P-Na(I) and the same acoustical arrangement of ultrasound substantially enhanced nitroxide generation by the cells. Sonodynamically induced apoptosis, caspase-3 activation, and nitroxide generation were significantly suppressed by histidine. These results indicate that the combination of ultrasound and DCPH-P-Na(I) induced apoptosis in HL-60 cells. The significant reduction in sonodynamically induced apoptosis, nitroxide generation, and caspase-3 activation by histidine suggests active species such as singlet oxygen are important in the sonodynamic induction of apoptosis. These experimental results support the possibility of sonodynamic treatment for cancer using the induction of apoptosis.

Background: The sonodynamically-induced in vitro and in vivo antitumor effects of mono-l-aspartyl chlorin e6 (NPe6) was investigated., Materials and Methods: Both in vitro and in vivo antitumor effects were tested in combination with ultrasound at 2 MHz., Results: The rate of ultrasonically-induced damage on isolated sarcoma 180 cells in air-saturated suspension was enhanced two-fold with 80 μM NPe6. The co-administration of 25 mg/kg NPe6 followed by ultrasonic exposure at 2 MHz suppressed the growth of implanted colon 26 cell tumors at an intensity at which ultrasound alone showed only a slight antitumor effect., Conclusion: These in vitro and in vivo results suggest that NPe6 is a potential sensitizer for sonodynamic tumor treatment. The enhancement of cell damage by NPe6 was significantly inhibited by histidine, which may suggest reactive oxygen species plays a primary role in sonodynamically-induced antitumor effect.

In this study, we investigated the induction of apoptosis by ultrasound in the presence of the photochemically active gallium-porphyrin complex, 7,12-bis(1-decyloxyethyl)-Ga(III)-3,8,13,17-tetramethyl-porphyrin 2,18-dipropionyl diaspartic acid (ATX-70). HL-60 cells were exposed to ultrasound for up to 3 min in the presence and absence of ATX-70, and the induction of apoptosis was examined by analyzing cell morphology, DNA fragmentation, and caspase-3 activity. Cells treated with 80 μM ATX-70 and ultrasound clearly showed membrane blebbing and cell shrinkage, whereas significant morphologic changes were not observed in cells exposed to either ultrasound or ATX-70 alone. Also, DNA ladder formation and caspase-3 activation were observed in cells treated with both ultrasound and ATX-70 but not in cells treated with ultrasound or ATX-70 alone. In addition, the combination of ATX-70 and the same acoustical arrangement of ultrasound substantially enhanced nitroxide generation by the cells. Sonodynamically induced apoptosis, caspase-3 activation, and nitroxide generation were significantly suppressed by histidine. These results indicate that the combination of ultrasound and ATX-70 induces apoptosis in HL-60 cells. The significant reduction in sonodynamically induced apoptosis, nitroxide generation, and caspase-3 activation by histidine suggests that active species such as singlet oxygen are important in the sonodynamic induction of apoptosis.

Aim: The ultrasonically induced effect of a tumor accumulative derivative of rose bengal (RB) on isolated tumor cells was investigated to clarify whether the RB derivative (RBD) maintains the sonosensitizing ability of RB., Materials and Methods: Sarcoma 180 cells were suspended in air-saturated phosphate-buffered saline and were exposed to ultrasound in standing wave mode for up to 60 s in the presence and absence of RBD or RB. The viability of the cells was determined by the ability to exclude trypan blue., Results: The ultrasonically induced cell-damaging rate with 100 μM RBD was one order of magnitude higher than that with the same concentration of RB. This increase was significantly inhibited by the active oxygen scavengers histidine, tryptophan and N-acetyl-L-cysteine., Conclusion: Chemical modification of RB to RBD for tumor accumulation significantly increased the sonodynamically induced antitumor effect of RB.

Background: Ultrasonically induced cell damage and active oxygen generation with a novel porphyrin derivative DCPH-P-Na(I), were compared in the same in vitro insonation setup., Materials and Methods: Sarcoma 180 cells suspended in air-saturated PBS were exposed to ultrasound at 2 MHz for up to 60 s in the presence and absence of DCPH-P-Na(I). Cell viability was determined with the trypan blue exclusion test. Lipid peroxidation in cell membranes was estimated by measuring the amount of reactive substance produced immediately following the addition of thiobarbituric acid., Results: Significant enhancement of the rates of both ultrasonically induced cell damage and lipid peroxidation was observed in the presence of 2-8 muM DCPH-P-Na(I). Both rates correlated very well., Conclusion: The enhancement of both rates with DCPH-P-Na(I) was suppressed by 10 mM histidine. These results suggest that ultrasonically generated active oxygen plays a primary role in the ultrasonically induced cell damage in the presence of DCPH-P-Na(I).

Unglycosylated recombinant human alpha(1)-acid glycoprotein (hAGP) variants (rF1(*)S and rA) were prepared in an E. coli expression system using the Origami B strain and pET-3c vector. Thioredoxin was co-expressed to promote the appropriate folding of hAGP. SDS-PAGE under reducing conditions showed that rF1(*)S and rA migrate as single bands after purification. However, several bands derived from rA were observed under non-reducing conditions because of the high reactivity of a free cystein residue (C149). We therefore prepared a mutant of A variant (C149R-A), and confirmed that this mutant maintained homogeneity. Circular dichroism and intrinsic tryptophan fluorescence spectroscopic analyses indicated that rF1(*)S and C149R-A have almost the same conformational structures as F1(*)S and A purified from serum. Ligand binding experiments using propranolol as a F1(*)S ligand and disopyramide as an A specific ligand indicated that the capacity of rF1(*)S and C149R-A is equivalent to those ligands as well as F1(*)S and A from serum. These results suggest that the oligosaccharide moieties of hAGP have negligible effects on the structural and ligand binding properties of hAGP. Thus, rF1(*)S and C149R-A promise to be useful in studies on the drug binding sites of hAGP.

In this study, we investigated the induction of apoptosis by ultrasound in the presence of a photochemically active chlorin, mono-l-aspartyl chlorin e6 (NPe6). HL-60 cells were exposed to ultrasound for up to 3 min in the presence and absence of NPe6, and the induction of apoptosis was examined by analyzing cell morphology, DNA fragmentation, and caspase-3 activity. Cells treated with 80 microM NPe6 and ultrasound clearly showed membrane blebbing and cell shrinkage, whereas significant morphologic changes were not observed in cells exposed to either ultrasound alone, at the same intensity, or NPe6 alone. Also, DNA ladder formation and caspase-3 activation were observed in cells treated with both ultrasound and NPe6 but not in cells treated with ultrasound or NPe6 alone. In addition, NPe6 substantially enhanced nitroxide generation by ultrasound in the same acoustical arrangement. Sonodynamically-induced apoptosis, caspase-3 activation, and nitroxide generation were significantly suppressed by histidine. These results suggest that the combination of ultrasound and NPe6 sonochemically induces apoptosis as well as necrosis in HL-60 cells. They further suggest that some ultrasonically-generated active species, deactivatable by histidine, are the major mediators to induce the observed apoptosis.

Sonodynamically induced apoptosis with porfimer sodium in HL-60 cells was investigated. HL-60 cells were exposed to ultrasound for up to 3 min in the presence and absence of porfimer sodium. After the exposure, sonodynamically induced apoptosis was assessed according to morphologic changes, DNA fragmentation and caspase-3 activation. The cells treated with 50 mug/ml porfimer sodium and ultrasound clearly showed membrane blebbing and cell shrinkage, whereas no significant morphologic change was observed in the cells exposed to either ultrasound alone or porfimer sodium alone. DNA ladder formation was observed in the cells treated with ultrasound in the presence of porfimer sodium. Activation of caspase-3 was also observed after the treatment with ultrasound and porfimer sodium. Both sonodynamically induced apoptosis and caspase-3 activation were significantly suppressed by histidine. These results indicate that combination treatment with ultrasound and porfimer sodium induced apoptosis in HL-60 cells. Significant reduction by histidine in both sonodynamically induced apoptosis and caspase-3 activation suggests that some ultrasonically generated active species, deactivatable by histidine, are the major mediators to induce the observed apoptosis.

Sonodynamically induced antitumor effect of a gallium porphyrin complex, ATX-70 was evaluated on a chemically induced mammary tumor in Sprague-Dawley rats. The timing of 24 h after the administration of ATX-70 was chosen for ultrasonic exposure, based on pharmacokinetic analysis of ATX-70 concentrations in the tumor, plasma, skin, and muscle. At an ATX-70 dose not less than 2.5 mg/kg and at a free-field ultrasonic intensity not less than 3 W/cm(2), the synergistic effect between ATX-70 administration and ultrasonic exposure on the tumor growth inhibition was significant. These results suggest that ATX-70 is a potential sonosensitizer for sonodynamic treatment of spontaneous mammary tumors.

The sonodynamically induced antitumor effect of porfimer sodium (PF) was evaluated on a chemically induced mammary tumor in Sprague-Dawley rats. The timing of 24 h after the administration of PF was chosen for the ultrasonic exposure, based on pharmacokinetic analysis of the PF concentrations in the tumor, plasma, skin and muscle. At a PF dose not less than 2.5 mg/kg and at a free-field ultrasonic intensity not less than 3 W/cm2, the synergistic effect between PF administration and ultrasonic exposure on the tumor growth inhibition was significant. The ultrasonic intensity showed a relatively sharp threshold for the synergistic antitumor effect, which is typical of an ultrasonic effect mediated by acoustic cavitation. These results suggest that PF is a potentially useful as a sonosensitizer for sonodynamic treatment of chemically induced tumors.

Acoustic cavitation is the primary mechanism of sonochemical reaction and has potential use for tumor treatment in combination with a certain sonodynamically active agent. It has been known that inducing cavitation with progressive waves is more difficult than with standing waves. This may have been limiting the sonodynamic treatment of tumors. We found that ultrasonically induced chemical reactions are greatly accelerated when the second harmonic is superimposed onto the fundamental. Experimental murine tumors were treated with progressive waves in combination with administration of a gallium-porphyrin complex (ATX-70). The tumors treated with second-harmonic superimposition stopped growing for about 2 days and then gradually started growing again. When only 0.5 MHz was used, tumor growth was not significantly different from that in untreated tumors. It was significantly slower than the untreated when only 1.0 MHz was used, but it was significantly further slowed when second-harmonic superimposition was used. The tumor-bearing mice treated with second-harmonic superimposition after ATX-70 administration survived 5 days longer on average than those untreated.

Purpose: Ultrasonically induced cell damage and active oxygen generation with photofrin II were compared using the same in vitro insonation setup., Methods: Sarcoma 180 cells suspended in an air-saturated phosphate-buffered saline solution were exposed to ultrasound at 2 MHz for not more than 60 s in the presence and absence of photofrin II. The trypan blue exclusion test was used to determine viability. Lipid peroxidation in cell membranes was estimated by measuring the quantity of reactive substance produced from thiobarbituric acid added immediately after the cells had been exposured to ultrasound., Results: Significant enhancement of the rates of ultrasonically induced cell damage and lipid peroxidation was demonstrated with photofrin II (20-80 µg/ml), and the two rates were closely associated. Enhancement of both rates by photofrin II was suppressed by 10 mM of histidine., Conclusion: These results suggest that ultrasonically generated active oxygen is a primary factor in ultrasonically induced cell damage in the presence of photofrin II.

The sonodynamically induced antitumour effect of chloroaluminum phthalocyanine tetrasulfonate (AlPcTS) was evaluated on subcutaneously implanted colon 26 carcinoma. A time of 24 h after the administration of AlPcTS was chosen for the ultrasonic exposure, based on the analysis of the AlPcTS concentrations in the tumour, plasma, skin and muscle. The pharmacokinetic analysis showed much faster clearance of AlPcTS than photofrin II from the body, which can be an advantage in view of their potential adverse effects. At an AlPcTS dose not less than 2.5 mg kg(-1) and at a free-field ultrasonic intensity not less than 3 W cm(-2), the synergistic effect between AlPcTS administration and ultrasonic exposure on the tumour growth inhibition was significant. The ultrasonic intensity showed a relatively sharp threshold for the synergistic antitumour effect, which is typical for an ultrasonic effect mediated by acoustic cavitation. These results suggest that AlPcTS is a potential sonosensitizer for sonodynamic treatment of solid tumours.

Ultrasonically induced cell damage and active oxygen generation with 4-formyloximeetylidene-3-hydroxyl-2-vinyl-deuterio-porphynyl(IX)-6-7-diaspartic acid (ATX-S10) were compared in the same in vitro insonation setup. Sarcoma 180 cells suspended in air-saturated PBS were exposed to ultrasound at 2 MHz for up to 60 s in the presence and absence of ATX-S10. The viability was determined by Trypan blue exclusion test. Ultrasonically induced active oxygen generation in the presence and absence of ATX-S10 in air-saturated aqueous solutions of 50 mM 2,2,6,6-tetramethyl-4-piperidone was detected by electron spin resonance (ESR). Significant enhancement of the rates of both ultrasonically induced cell damage and nitroxide generation was demonstrated with 40-160 microM ATX-S10. Both rates correlated very well. The enhancement of both rates with ATX-S10 was suppressed by 10 mM histidine. These results suggest that ultrasonically generated active oxygen plays a primary role in the ultrasonically induced cell damage in the presence of ATX-S10.

The ultrasonically induced cytotoxic effect of erythrosin B (EB) on isolated sarcoma 180 cells was investigated. The tumor cells were suspended in an air-saturated phosphate buffered saline and exposed to ultrasound at 1.93 MHz in a standing-wave mode for up to 60 s in the presence and absence of EB. The rate of cell damage induction by ultrasound was enhanced by 4-5 times with 160-microM EB, while no cell damage was observed with EB alone. This enhancement was significantly inhibited by histidine. Sonochemical generation of active oxygen species in the presence of EB, measured by ESR spectroscopy, was also inhibited by histidine. These results indicate the involvement of a sonochemical mechanism.

The tissue distribution of a gallium-porphyrin photo- and sono-sensitizer, 7,12-bis(1-decyloxyethyl)-Ga(III)-3,8,13,17-tetramethylporphyrin-2,18-dipropionyldiaspartic acid, ATX-70, was pharmacokinetically examined in tumor-bearing mice. The drug was administered intravenously to CDF(1) mice implanted with Colon 26 carcinoma. Blood and tissue samples were collected for up to 72 h after administration. The drug concentration was determined by high-performance liquid chromatography (HPLC) with fluorescence detection. ATX-70 was found to accumulate in tumors at a relatively high concentration that peaked between 2 h and 6 h after administration. However, modest concentrations of ATX-70 also remained in healthy tissues for up to 6 h. We examined the distribution of ATX-70 in the tumor in comparison with other tissues from the viewpoint of minimizing possible side effects of laser or ultrasound exposure while maintaining the treatment effect. About 24 h after administration, the tumor / plasma concentration ratio peaked, and relatively high tumor / skin and tumor / muscle concentration ratios were seen.

Ultrasound has two major biological effects potentially to be utilized for tumor treatment: heating and cavitational effects. In coagulation treatment, the tissue in the focal spot is heated above the coagulation temperature in a relatively short period of time with high intensity focused ultrasound so that the irreversible change in tissue is completed much earlier than the temperature distribution blurs due to heat conduction. However, the smallness of the coagulation volume formed by an ultrasonic shot causes the problem of low treatment throughput. The split-focus technology, in which the focal spot is enlarged in the lateral rather than longitudinal direction, multiplies the coagulation volume so as to solve this problem. Sonodynamic treatment was proposed based on the recent in vitro and in vivo experimental findings that ultrasonic cavitation can activate certain porphyrins and thereby induce significant antitumor effects. It was also found that the ultrasonic intensity threshold for producing cavitation can be significantly reduced by superimposing the second harmonic onto the fundamental. The threshold to form a focal lesion in murine liver tissue was reduced by orders of magnitude, especially in combination with administration of a certain xanthene dye.

The sonodynamically induced antitumor effect of Photofrin II (PF), was evaluated in mice bearing colon 26 carcinoma. In order to find the optimum timing for ultrasonic exposure after the administration of PF, the PF concentrations in the plasma, skin, muscle, and tumor were measured. The antitumor effect was estimated by measuring the tumor size. Since the highest concentration of PF in the tumor was observed 24 h after administration, an ultrasonic exposure timing of 24 h after the intravenous administration of PF was chosen. When used alone, ultrasound showed a slight antitumor effect, which became increasingly significant as the dose of PF was increased, while use of PF alone showed no significant effect. From these results, it is concluded that PF significantly sensitizes solid tumors to ultrasound, demonstrating a synergistic antitumor effect.

Unlabelled: Ultrasonically induced cell damage and active oxygen generation with photofrin II (PF) were compared in the same in vitro insonation setup., Materials and Methods: Sarcoma 180 cells suspended in air-saturated PBS were exposed to ultrasound for up to 60 seconds in the presence and absence of PF. The viability was determined by the Trypan Blue exclusion test. Ultrasonically induced active oxygen generation in the presence and absence of PF in air-saturated aqueous solutions of 50 mM 2,2,6,6-tetramethyl-4-piperidone was detected by electron spin resonance (ESR) spectrum., Results: Significant enhancement of the rates of both ultrasonically induced cell damage and nitroxide generation was demonstrated with 20-80 micrograms/ml PF. Both rates correlated very well. The enhancement of both rates with PF was suppressed by 10 mM histidine., Conclusion: These results may suggest that ultrasonically generated active oxygen plays a primary role in ultrasonically induced cell damage in the presence of PF.

We studied a combination of photodynamic therapy (PDT) and sonodynamic therapy (SDT) for improving tumoricidal effects in a transplantable mouse squamous cell carcinoma (SCC) model. Two sensitizers were utilized: the pheophorbide-a derivative PH-1126, which is a newly developed photosensitizer, and the gallium porphyrin analogue ATX-70, a commonly used sonosensitizer. Mice were injected with either PH-1126 or ATX-70 i.p. at doses of 5 or 10 mg/kg.bw. At 24 (ATX-70) or 36 hr (PH-1126) (time of optimum drug concentration in the tumor) after injection, SCCs underwent laser light irradiation (88 J/cm2 of 575 nm for ATX-70; 44J/cm2 of 650 nm for PH-1126) (PDT), ultrasound irradiation (0.51 W/cm2 at 1.0 MHz for 10 minutes) (SDT), or a combination of the two treatments. The combination of PDT and SDT using either PH-1126 or ATX-70 as a sensitizer resulted in significantly improved inhibition of tumor growth (92-98%) (additive effect) as compared to either single treatment (27-77%). The combination using PH-1126 resulted in 25% of the treated mice being tumor free at 20 days after treatment. Moreover, the median survival period (from irradiation to death) of PDT + SDT-treated mice (> 120 days) was significantly greater than that in single treatment groups (77-95 days). Histological changes revealed that combination therapy could induce tumor necrosis 2-3 times as deep as in either of the single modalities. The combination of PDT and SDT could be very useful for treatment of non-superficial or nodular tumors.

The sonodynamically induced antitumor effect of 4-formyloximethylidene-3-hydroxy-2-vinyl-deuterio-porphyn yl(IX)-6,7-diaspartic acid (ATX-S10) was investigated. Both in vitro and in vivo antitumor effects were tested in combination with ultrasound at 2 MHz. The rate of ultrasonically induced damage to isolated sarcoma 180 cells in air-saturated suspension was enhanced two-fold with 80 microM ATX-S10. This enhancement was significantly inhibited by histidine, which may suggest that it was mediated by ultrasonically induced oxidation. The coadministraion of 25 mg/kg ATX-S10 followed by ultrasonic exposure at 2 MHz stopped the growth of implanted colon 26 tumors at an intensity at which ultrasound alone showed only a slight antitumor effect.

Background: 4'-O-tetrahydropyranyladriamycin (THP) is a novel anthracycline derivative with cardiotoxicity significantly lower than ADM. In this study, the ultrasonically induced in vitro cell damaging effect of THP was investigated., Materials and Methods: Sarcoma 180 cells suspended in air-saturated PBS were exposed to ultrasound for up to 60 s in the presence and absence of THP. The viability of the isolated cells was determined by staining of the cells with Trypan Blue dye., Results: The rate of inducing cell damage with ultrasound was doubled with 80 microM THP, while no cell damage was observed with THP alone., Conclusion: The enhancement of ultrasonically induced in vitro cell damage was demonstrated with THP. This enhancement was significantly inhibited by histidine, which may suggest a sonochemical mechanism.

The antitumor effect of focused ultrasound in combination with Ga-porphyrin complex, 7,12-bis(1-decyloxyethyl)-Ga(III)-3,8,13,17 tetramethylporphyrin-2,18-dipropionyl diaspartic acid (ATX-70), on the growth of experimental murine tumors was examined. Walker 256 tumors implanted in rat kidneys were exposed in a progressive wave field for 5 min to focused ultrasound at 500 kHz with the second harmonic (at 1 MHz) superimposed after administration of ATX-70 to the rats. A significant antitumor effect was obtained at a focal-spot average acoustic intensity of 12 W/cm2 or higher with an ATX-70 dose of not less than 2.5 mg/kg. When the acoustic intensity was 8 W/cm2 or lower, no significant effect was observed even at an ATX-70 dose of 2.5 mg/kg. Also when the ATX-70 dose was 1.0 mg/kg or lower, no significant effect was observed even at a focal-spot average acoustic intensity of 40 W/cm2.

The antitumor effect of a gallium-porphyrin complex, ATX-70, induced by focused ultrasound, on colon 26 carcinoma implanted in a mouse kidney was investigated. Colon 26 tumors were exposed to focused ultrasound at 500 kHz and 1 MHz in a progressive wave mode. Both frequency components were superimposed onto each other in the focal zone to efficiently produce cavitation in the tumor. ATX-70 was administered intravenously at the dose of 2.5 mg/kg, 24 h before the ultrasonic exposure. Antitumor effects were evaluated by histological observation 7 days after the exposure. The destruction of tumor tissue was observed with the ultrasonic treatment in combination with ATX-70, while neither the treatment with ATX-70 alone nor that with ultrasound alone caused any necrosis. These results first demonstrated that antitumor effects of a porphyrin compound can be induced by focused ultrasound in a progressive wave mode.

The sonodynamically induced antitumor effect of a gallium-porphyrin complex, ATX-70, was evaluated in mice bearing colon 26. In order to find the optimum timing for the ultrasonic exposure after the administration of ATX-70, the ATX-70 concentrations in the plasma, skin, and tumor were measured and analyzed. Antitumor effect was estimated by measuring the tumor size. When used alone, ultrasound showed a slight antitumor effect, which became increasingly significant as the dose of ATX-70 was increased, while use of ATX-70 alone had no significant effect. At an ATX-70 dose of 2.5 mg/kg or higher, the average tumor size decreased to smaller than a half by three days after the ultrasonic exposure. This was smaller than a third of the size of the untreated tumors on the same day. From these results, it is concluded that ATX-70 significantly sensitizes tumors to ultrasound, demonstrating a synergistic antitumor effect.

The production of 2,2,6,6-tetramethyl-4-piperidone-N-oxyl by reaction of 2,2,6,6-tetramethyl-4-piperidone (TMPone) with ultrasonically generated active species in oxygenated solutions of hematoporphyrin (Hp) was studied by electron spin resonance spectroscopy. The nitroxide production rate in air-saturated TMPone solutions in phosphate-buffered saline of pH 9.0 was significantly higher in the presence of Hp than in its absence. The enhancement of nitroxide production by Hp was significantly inhibited in the presence of sodium azide or histidine in the solution. The production rate with Hp was doubled by substitution of deuterium oxide, while the rate without Hp increased only modestly. These results suggest that a substantial amount of active oxygen can be generated by ultrasound in aqueous solutions of Hp. Since the production rate was not reduced by mannitol and no nitroxide was produced in nitrogen-saturated solutions, it appears that hydroxyl radicals do not account for a major portion of the active oxygen species which reacted with TMPone to yield a nitroxide.

Enhancement of ultrasonically induced cell damage by a gallium-porphyrin complex [ATX-70, 2,4-bis(1-decyloxyethyl)-Ga(III)-1,3,5,8- tetramethylporphryin-6,7-dipropionyl diaspartic acid] was investigated. The rate of damage to isolated sarcoma 180 cells in air-saturated suspension induced by 2 MHz ultrasound irradiation was enhanced more than four times by 80 microM ATX-70 in contrast to only twice by the same concentration of hematoporphyrin (Hp). The enhancement was almost completely inhibited in the presence of 10 mM histidine in the suspension, but not at all by 100 mM mannitol, which suggests that the enhanced cell damage was mostly mediated by singlet oxygen. Ultrasonically induced active oxygen generation in an air-saturated aqueous solution of ATX-70 was studied by detecting the electron spin resonance signals of 2,2,6,6,-tetramethyl-4-piperidone-N-oxyl produced by the reaction of 2,2,6,6-tetramethyl-4-piperidone with the generated active oxygen species. The rate of ultrasonically induced nitroxide generation was enhanced five times by 80 microM ATX-70 in contrast to only twice by Hp. The enhancement was inhibited significantly in the presence of 10 mM histidine in the suspension, but not at all by 100 mM mannitol. The singlet oxygen generation in air-saturated aqueous solution was further confirmed by the bleaching of N,N-dimethyl-4-nitrosoaniline in the presence of imidazole. The ultrasonically induced bleaching rate was enhanced six times by ATX-70, in contrast to only twice by Hp.