Antitumoral efficacy and pharmacokinetic properties of pirarubicin upon hepatic intra-arterial injection in the rabbit V x 2 tumour model

Ferroptosis: action and mechanism of chemical/drug-induced liver injury

Drug-induced liver injury (DILI) is characterized by hepatocyte injury, cholestasis injury, and mixed injury. The liver transplantation is required for serious clinical outcomes such as acute liver failure. Current studies have found that many mechanisms were involved in DILI, such as mitochondrial oxidative stress, apoptosis, necroptosis, autophagy, ferroptosis, etc. Ferroptosis occurs when hepatocytes die from iron-dependent lipid peroxidation and plays a key role in DILI. After entry into the liver, where some drugs or chemicals are metabolized, they convert into hepatotoxic substances, consume reduced glutathione (GSH), and decrease the reductive capacity of GSH-dependent GPX4, leading to redox imbalance in hepatocytes and increase of reactive oxygen species (ROS) and lipid peroxidation level, leading to the undermining of hepatocytes; some drugs facilitated the autophagy of ferritin, orchestrating the increased ion level and ferroptosis. The purpose of this review is to summarize the role of ferroptosis in chemical- or drug-induced liver injury (chemical/DILI) and how natural products inhibit ferroptosis to prevent chemical/DILI.

Experimental VX2 Rabbit Liver Tumor Model in Carbon Tetrachloride-Induced Cirrhosis of the Liver

Liver cirrhosis is a major underlying factor in the development of hepatocellular carcinoma. Currently, there is an unmet need for midsize experimental vertebrate models that would offer reproducible implantable liver tumors in a cirrhotic liver background. This study establishes a protocol for a syngeneic rabbit model of VX2 liver cancer with underlying liver cirrhosis induced using carbon tetrachloride (CCl4). Male New Zealand white rabbits (n = 3) received CCl4 by intragastric administration once weekly. Concentrations started at 5% v/v CCl4 dissolved in olive oil. CCl4 dosing was progressively increased every week by 2.5% v/v increments for the duration of treatment (16 weeks total). VX2 tumors were then orthotopically implanted into the left hepatic lobe and allowed to grow for 3 weeks. Cross-sectional imaging confirmed the presence of hepatic tumors. Gross and histopathological evaluations showed reproducible tumor growth in the presence of liver cirrhosis in all animals.

Anti-fibrosis potential of pirarubicin via inducing apoptotic and autophagic cell death in rabbit conjunctiva

This study investigated the potential efficacy of pirarubicin (THP) in modulating rabbit conjunctival fibrosis both in vitro and in vivo and characterized the underlying mechanisms. Primary rabbit conjunctival fibroblasts (RCF) were cultured and treated with THP or mitomycin C (MMC) for 5 min, followed by assaying for cell viability, cell cycle distribution, apoptotic and autophagic pathways. The production of reactive oxygen species (ROS) and chemotaxis of macrophages by RCF were evaluated using 2',7'-dichlorofluorescein diacetate (DCFH-DA) labeling and transwell migration assay, respectively. Limbal stem cell excision in combination with alkali burn was performed on the rabbits to establish a model of limbal deficiency and conjunctival fibro-vascular invasion. After three months, the modeled fibro-vascular tissue was excised combined with topical subconjunctival 5-min exposure to THP compared with MMC intraoperatively. The recurrence of postoperative fibrosis and the expression of apoptosis, autophagy, and inflammation markers were evaluated by immunohistochemistry. All modeled rabbits developed conjunctival fibro-vascular lesions, which were similar to human recurrent pterygium (HRP). Both THP and MMC inhibited RCF proliferation and arrested cell cycle at the G0/G1 phase. In particular, 7.5 μmol/L THP remarkably promoted RCF autophagy by upregulating the levels of Beclin 1, Atg 5/12 conjugate, and LC3B, whereas, 15 μmol/L THP significantly triggered a cascade of mitochondrial-associated RCF apoptosis. THP induced the production of ROS and enhanced the chemoattraction of macrophages by RCF. Similar to 600 μmol/L MMC, both 7.5 μmol/L and 15 μmol/L THP attenuated postoperative conjunctival fibrosis in the models; 7.5 μmol/L THP preferentially enhanced autophagy while causing fewer side effects. THP exerted its antifibrotic action by modulating autophagy in RCF, inducing cell cycle arrest, and mitochondrial-mediated apoptosis. THP at the dose of 7.5 μmol/L prevented postoperative conjunctival fibrosis in an animal model.

Low concentration of rutin treatment might alleviate the cardiotoxicity effect of pirarubicin on cardiomyocytes via activation of PI3K/AKT/mTOR signaling pathway

Cancer is the leading cause of deaths around the world, especially in low- and middle- income countries. Pirarubicin (THP) is an effective drug for treatment of cancer, however, there still exists cardiotoxic effects of THP. Rutin is a kind of antioxidative compound extracted from plants, and might be a protective compound for cardiomyocytes. Phosphatidylinositol 3-hydroxy kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway is critical for cellular survival, proliferation and metabolism, and thus we speculated rutin might perform a protective role in cardiomyocytes via PI3K/AKT/mTOR signaling pathway. And in this experiment, we first established a cardiotoxicity model of THP in mice model and cell models, and then found that rutin treatment could increase the proliferation of cells at low concentration. Then we explored the possible mechanism of the protective effect of rutin using Western blotting, quantitative polymerase chain reaction (qPCR) and ELISA methods, and found that the activation of PI3K/AKT/mTOR/nuclear factor-κB (NF-κB) signaling pathway was increased, and expression of downstream molecules involved in antioxidative stress were also increased. We further noticed that concentration of angiogenesis promoting factors were also increased in medium of cultured cells. Thus, we speculated that rutin could increase the activation of PI3K/AKT/mTOR signaling pathway, further decrease the oxidative stress level via increasing the expression of antioxidative stress enzymes with the increasing concentration of angiogenesis promoting factors, resulting in the protective role in cardiomyocytes and cardiac function.

RIPK1 Inhibition Enhances Pirarubicin Cytotoxic Efficacy through AKT-P21-dependent Pathway in Hepatocellular Carcinoma

Pirarubicin (THP) is a new generation cell cycle nonspecific anthracycline anticancer drug. Pirarubicin and pirarubicin-based combination therapies have been demonstrated to be effective against HCC in TACE. However, the drug resistance limits its therapeutic efficacy. Receptor-interacting protein kinase 1 (RIPK1) displays a critical role in cell death. Here we found that RIPK1 and p21 may participate in the resistance to pirarubicin. In this study, we first found that inhibition of RIPK1 significantly decreased pAKT and increased p21, accompanied by G0/G1 phase cell cycle arrest and cell anti-proliferation in pirarubicin-treated hepatocellular carcinoma cells. Moreover, phosphorylation of AKT reversed the anti-proliferative effect of RIPK1 inhibitor in HCC, which proved that RIPK1-AKT-P21-dependent pathway played a key role in pirarubicin resistance. Using a mouse xenograft model, we further found that RIPK1 inhibitor combined with pirarubicin exerted synergistic anti-tumor effect in vivo. Upon exposure to pirarubicin treatment, xenografts under RIPK1 inhibition maintained higher levels of p21 than control xenografts. In conclusion, the results in our study demonstrated that RIPK1 inhibition enhances the anti-tumor effect of pirarubicin by overcoming drug resistance. RIPK1 inhibitor might be used as an adjuvant to potentiate the inhibitory effect of pirarubicin against primary hepatocellular carcinoma.

VEGFR-1 targeted DNAzyme via transcatheter arterial delivery influences tumor vasculature assessed through dynamic contrast-enhanced magnetic resonance imaging

DNAzymes are synthetic single-stranded DNA oligonucleotides that bind and cleave target mRNA in a sequence-specific manner. Although the therapeutic potential has been demonstrated in both preclinical and clinical settings, the efficient delivery and in vivo assessment of the DNAzyme efficacy remain the vital unsolved issue. In the present study, we examined the feasibility of using transcatheter arterial chemoembolization (TACE) strategy to deliver a DNAzyme targeting VEGFR-1 and monitoring its effect on tumor angiogenesis in vivo via dynamic contrast enhanced magnetic resonance imaging (DCE-MRI). In a rabbit liver cancer model (VX2), we showed that the DNAzyme was efficiently delivered into the tumor by TACE. DCE-MRI revealed that the VEGFR-1-targeted DNAzyme affected the tumor vasculature through inhibiting VEGFR-1 expression in vivo, which was reflected by a reduction of Ktrans and Kep, the parameters of tumor microvascular permeability. Our findings offer an efficient strategy of delivery and assessment of the VEGFR-1 DNAzyme, and further demonstrate the feasibility of DNAzyme for cancer therapy.

A small interfering RNA targeting vascular endothelial growth factor efficiently inhibits growth of VX2 cells and VX2 tumor model of hepatocellular carcinoma in rabbit by transarterial embolization-mediated siRNA delivery

Introduction

Hepatocellular carcinoma is currently the second leading cause of cancer-related deaths worldwide with an increasing incidence.

Objective

The objective of this study is to investigate the effect of vascular endothelial growth factor small interfering RNA (VEGF-siRNA) on rabbit VX2 carcinoma cell viability in vitro and the effect of transarterial embolization (TAE)-mediated VEGF-siRNA delivery on the growth of rabbit VX2 liver-transplanted model in vivo.

Methods

Quantitative reverse transcription polymerase chain reaction, enzyme-linked immunosorbent assay, and Western blot technologies were used to detect the expression level of VEGF. TAE and computed tomography scan were used to deliver the VEGF-siRNA and detect the tumor volume in vivo, respectively. Microvessel density was detected by immunohistochemistry with CD34 antibody. A biochemical autoanalyzer was used to evaluate the hepatic and renal toxicity.

Results

The designed VEGF-siRNAs could effectively decrease the expression levels of VEGF mRNA and protein in vitro and in vivo. In vitro, the viability of rabbit VX2 carcinoma cells was reduced by 38.5%±7.3% (VEGF-siRNA no 1) and 30.0%±5.8% (VEGF-siRNA no 3) at 48 hours after transfection. Moreover, in rabbit VX2 liver-transplanted model, the growth ratios of tumors at 28 days after TAE-mediated siRNA delivery were 155.18%±19.42% in the control group, 79.67%±19.63% in the low-dose group, and 36.09%±15.73% in the high-dose group, with significant differences among these three groups. Microvessel density dropped to 34.22±4.01 and 22.63±4.07 in the low-dose group and high-dose group, respectively, compared with the control group (57.88±5.67), with significant differences among these three groups. Furthermore, inoculation of VX2 tumor into the liver itself at later stage induced significant increase in alanine aminotransferase and aspartate aminotransferase, indicating an obvious damage of liver functions, while treatment of VX2 tumor via TAE-mediated VEGF-siRNA had no toxicity to the livers and kidneys of rabbits, and VEGF-siRNA had the ability to protect liver damage induced by tumor growth.

Conclusion

This is the first study to demonstrate that targeting VEGF via TAE-mediated siRNA delivery may become a powerful new option for effective treatment of hepatocellular carcinoma in the clinic.

A novel sulfamethazine-based pH-sensitive copolymer for injectable radiopaque embolic hydrogels with potential application in hepatocellular carcinoma therapy

After transcatheter delivery through hepatic artery, a hydrogel can be formed within tumor vasculature by the decrease of environmental pH, block the blood vessel and control the release of loaded anticancer drugs.

Dynamical observation on biological progression of VX2 liver tumors to identify the optimal time for intervention in animal models

Purpose

Based on practice guideline of “management of hepatocellular carcinoma (HCC): update” published by American Association for the Study of Liver Diseases (AASLD) and “Barcelona Clinic Liver Cancer staging system (BCLC),” this study investigated how to enroll the optimal VX2 liver tumor model for HCC researches by dynamically observing the biological progression of the tumor.

Materials

Thirty-two healthy New Zealand white rabbits were implanted VX2 liver tumor by cell suspension method (n=24) and tissue fragment method (n=8). All the rabbits underwent CT scans on day 7, 14, 21 and 28 after implantation to observe the size of the tumors, the time when metastases and ascites occurred and the survival time. Appropriate intervention times were estimated corresponding to different clinical HCC stages by using tumor diameter-time curve.

Results

The VX2 liver tumors grew rapidly within 28 days after implantation. And the tumors in the cell suspension group grew faster than those of the tissue fragment group. The appropriate intervention time corresponding to very early stage, early stage and intermediate stage were <11 days, 11–16.9 days and >16.9 days, respectively in the cell suspension group, and <19.9 days, 19.9–25.5 days and >25.5 days, respectively in the tissue fragment group.

Conclusion

Preclinical animal research needs to improve on different levels to yield best predictions for human patients. Researchers should seek for an individualized proposal to select optimal VX2 liver tumor models for their experiments. This approach may lead to a more accurate determination of therapeutic outcomes.

Effect of alginate-chitosan sustained release microcapsules for transhepatic arterial embolization in VX2 rabbit liver cancer model

Two lipid-solid dispersion loading Norcantharidin sustained-released microspheres of alginate-chitosan (NCTD/LSD-ACMs) were prepared via the emulsification-gelation method. The effects of microspheres for transarterial hepatic chemoembolization were evaluated in VX2 rabbit liver cancer model. The VX2 animal model was established by biopsy needle, divided randomly into four groups, and disposed with three preparations including NCTD/LSD-ACMs (60-120 μm), NCTD/LSD-ACMs(120-200 μm), and NCTD solution through the hepatic arteries compared with the untreated group (control group). The serum of all rabbits before and at 3, 7, and 14 days after embolization was collected to determine the level of aspartate aminotransferase (AST). The AST level increased in the three treated groups on the first day compared with the control group (p < 0.05), and was higher in the two embolization groups (with no significant difference, p >0.05) than that in the NCTD group (p < 0.05). The tumor growth rates, which were significantly decreased in the two embolization groups compared with that in the control group, and the degree of liver cell necrosis assessed by the histopathological specimens, were used to evaluate the embolization effect. Liquefactive necrosis and coagulative necrosis were observed in the two embolization groups. The results showed that NCTD/LSD-ACMs are a potential candidate for embolization of liver cancer.

Chloroquine promotes the anticancer effect of TACE in a rabbit VX2 liver tumor model

BACKGROUND

To investigate the efficacy of TACE combined with CQ, an autophagic inhibitor, in a rabbit VX2 liver tumor model.

METHODS

Tumor size was measured. And tumor growth rate was calculated to examine the effect of the combined treatment. Apoptosis was detected by TUNEL assay. Meanwhile, autophagic activity was detected by immunohistochemistry and Western blotting to investigate the mechanism underlying. Liver function was also examined to assess feasibility and safety of the combined therapy.

RESULTS

Tumors in the control grew more than 4 times bigger after 14 days, while that in the group of TACE alone just showed mild growth. But a slight shrinkage was shown after the treatment of CQ+TACE. Growth ratio of TACE alone was 96.45% ± 28.958% while that of CQ+TACE was -28.73% ± 12.265%. Compared with TACE alone, necrosis in CQ+TACE showed no significant difference, however, the apoptosis was much higher. There were only 14.8±3.11% apoptotic cells in TACE, but 33±4.18% in CQ+TACE, which suggests the increased apoptosis in CQ+TACE contributed to the decrease of tumor volume. In terms of autophagic activity, the result is negative when we immunostained sections of the control with LC3 antibody, but positive in TACE alone and CQ+TACE. And the result of Western blot showed that there was just a low level of LC3Ⅱexpressed in the control and CQ alone, but higher in TACE, and much higher in CQ+TACE because CQ inhibited its degradation in autophagy. Compared with control, p62 decreased in TACE, but the decrease was partially reversed in CQ+TACE. In addition, toxicity of CQ+TACE was assessed not higher than TACE alone, which supports the safety of CQ+TACE.

CONCLUSION

CQ+TACE works better than TACE alone in rabbit VX2 liver tumor model because CQ inhibits autophagy induced by TACE. The inhibited autophagy loses its resistance to apoptosis that apoptosis increased, which contributes to the inhibition of tumor growth. This study indicates CQ may be a promising adjuvant to promote the effect of TACE.

The antitumor effect and hepatotoxicity of a hexokinase II inhibitor 3-bromopyruvate: in vivo investigation of intraarterial administration in a rabbit VX2 hepatoma model

Objective

The purpose of this study was to compare the antitumor effect and hepatotoxicity of an intraarterial delivery of low-dose and high-dose 3-bromopyruvate (3-BrPA) and those of a conventional Lipiodol-doxorubicin emulsion in a rabbit VX2 hepatoma model.

Materials and Methods

This experiment was approved by the animal care committee at our institution. VX2 carcinoma was implanted in the livers of 36 rabbits. Transcatheter intraarterial administration was performed using low dose 3-BrPA (25 mL in a 1 mM concentration, n = 10), high dose 3-BrPA (25 mL in a 5 mM concentration, n = 10) and Lipiodol-doxorubicin emulsion (1.6 mg doxorubicin/ 0.4 mL Lipiodol, n = 10), and six rabbits were treated with normal saline alone as a control group. One week later, the proportion of tumor necrosis was calculated based on histopathologic examination. The hepatotoxicity was evaluated by biochemical analysis. The differences between these groups were statistically assessed with using Mann-Whitney U tests and Kruskal-Wallis tests.

Results

The tumor necrosis rate was significantly higher in the high dose group (93% ± 7.6 [mean ± SD]) than that in the control group (48% ± 21.7) (p = 0.0002), but the tumor necrosis rate was not significantly higher in the low dose group (62% ± 20.0) (p = 0.2780). However, the tumor necrosis rate of the high dose group was significantly lower than that of the Lipiodol-doxorubicin treatment group (99% ± 2.7) (p = 0.0015). The hepatotoxicity observed in the 3-BrPA groups was comparable to that of the Lipiodol-doxorubicin group.

Conclusion

Even though intraarterial delivery of 3-BrPA shows a dose-related antitumor effect, single session treatment seems to have limited efficacy when compared with the conventional method.

Optimal strategies for combining transcatheter arterial chemoembolization and radiofrequency ablation in rabbit VX2 hepatic tumors

PURPOSE

To determine the optimum combination strategy of transcatheter arterial chemoembolization and radiofrequency (RF) ablation in an experimentally induced hepatic tumor model.

MATERIALS AND METHODS

Twenty-five New Zealand White rabbits with VX2 carcinoma-induced hepatic tumors were randomly divided into five treatment groups, which received (i) chemoembolization followed 15 minutes later by RF ablation; (ii) RF ablation followed by chemoembolization; (iii) chemoembolization alone; (iv) RF ablation alone; and (v) bland embolization followed by RF ablation. Animals were euthanized at 48 hours to determine tumor infarction and coagulation, which were compared with analysis of variance. Representative histopathologic slides were compared.

RESULTS

Significantly larger areas of coagulation were produced by chemoembolization followed by RF ablation (22.0 cm(3) +/- 7.7) compared with RF ablation followed by chemoembolization (13.1 cm(3) +/- 3.2) and RF ablation alone (10.0 cm(3) +/- 4.5; P < .05). RF ablation followed by chemoembolization showed larger treatment areas than chemoembolization alone (25.0 cm(3) +/- 9.6 vs 12.1 cm(3) +/- 4.6; P < .001), with chemotherapeutic agent preferentially depositing around the coagulation zone. Histopathologic analysis revealed greater vascular thrombosis and necrosis and reduced islands of viable tumor cells in the chemoembolization/RF ablation group versus the groups treated with chemoembolization alone or bland embolization/RF ablation.

CONCLUSIONS

Larger treatment volumes were produced when chemoembolization was performed before RF ablation than when RF ablation preceded chemoembolization or when RF ablation or chemoembolization were performed alone. Larger treatment volumes were also produced when chemoembolization rather than bland embolization was performed before RF ablation, indicating the importance and synergy of the chemotherapeutic regimen. These results suggest that the reduction of tumor blood flow combined with the effect of hyperthermia and local chemotherapy creates the largest dimensions of treatment.

[Research of beta-elemene interventional treatment on VX2 carcinoma transplanted on kidney in rabbits]

OBJECTIVE

To investigate the curative effect and mechanism of beta-elemene interventional treatment on VX2 carcinoma transplanted on kidney in rabbits.

METHODS

The rabbits were all transplanted with VX2 carcinoma on kidney. Fifty-five rabbits were randomly divided into 11 groups. Rabbits in these groups were administered interventional treatment of normal saline, iodinated oil, mitomycin, 5-fluorouracil, beta-elemene, cisplatin, carboplatin, adriamycin, thiotepa, cyclophopsphamide, and vincristine, respectively. After corresponding intervention, the tumor volume in each group was measured by ultrasonography and spiral computed tomography, and the tumor growth rate (TGR) was calculated. Nenal and hepatic functions of the rabbits in each group were compared 1 day, 7 and 14 days after the interventional treatment. Morphologic change of the tumor was observed by a light microscopy and a transmission electron microscopy 14 days after interventional treatment. The expressions of Bax and Bcl-2 were measured by immunohistochemical straining.

RESULTS

There was statistical significance in the effects of different medicines intervened on VX2 kidney transplanted carcinoma. The VX2 carcinoma of rabbits had high-sensitivity to iodized oil embolism, mitomycin, cisplatin and carboplatin, which showed serious damage to the kidney function, medium-sensitivity to beta-elemene, adriamycin and 5-fluorouracil, in which beta-elemene showed slight damage to the kidney function, and resistance to thiotepa, cyclohosphamide and vincristine. Most tumor cells displayed apoptosis in the beta-elemene interventional treatment group under light microscopy and transmission electron microscopy, and only few tumor cells displayed necrosis. The Bax expression was up-regulated (P<0.05) and the Bcl-2 expression had no significant difference (P>0.05) in the beta-elemene interventional treatment group.

CONCLUSION

Intervention treatment of beta-elemene has significant effect on VX2 kidney transplanted carcinoma and little side effect on the kidney function. Its mechanism is related to enhancing the apoptosis of tumor cells, and Bax gene participates in this action.

FDG-PET for evaluating the antitumor effect of intraarterial 3-bromopyruvate administration in a rabbit VX2 liver tumor model

OBJECTIVE

We wanted to investigate the feasibility of using FDG-PET for evaluating the antitumor effect of intraarterial administration of a hexokinase II inhibitor, 3-bromopyruvate (3-BrPA), in a rabbit VX2 liver tumor model.

MATERIALS AND METHODS

VX2 carcinoma was grown in the livers of ten rabbits. Two weeks later, liver CT was performed to confirm appropriate tumor growth for the experiment. After tumor volume-matched grouping of the rabbits, transcatheter intraarterial administration of 3-BrPA was performed (1 mM and 5 mM in five animals each, respectively). FDG-PET scan was performed the day before, immediately after and a week after 3-BrPA administration. FDG uptake was semiquantified by measuring the standardized uptake value (SUV). A week after treatment, the experimental animals were sacrificed and the necrosis rates of the tumors were calculated based on the histopathology.

RESULTS

The SUV of the VX2 tumors before treatment (3.87+/-1.51 [mean+/-SD]) was significantly higher than that of nontumorous liver parenchyma (1.72+/-0.34) (p < 0.0001, Mann-Whitney U test). The SUV was significantly decreased immediately after 3-BrPA administration (2.05+/-1.21) (p = 0.002, Wilcoxon signed rank test). On the one-week follow up PET scan, the FDG uptake remained significantly lower (SUV 1.41+/-0.73) than that before treatment (p = 0.002), although three out of ten animals showed a slightly increasing tendency for the FDG uptake. The tumor necrosis rate ranged from 50.00% to 99.90% (85.48%+/-15.87). There was no significant correlation between the SUV or the SUV decrease rate and the tumor necrosis rate in that range.

CONCLUSION

Even though FDG-PET cannot exactly reflect the tumor necrosis rate, FDG-PET is a useful modality for the early assessment of the antitumor effect of intraarterial administration of 3-BrPA in VX2 liver tumor.

Polybutylcyanoacrylate nanoparticles as a carrier for mitomycin C in rabbits bearing VX2-liver tumor

Polybutylcyanoacrylate nanoparticles (PBCA-NP) were prepared by addition of the monomer to an aqueous phase containing dextran 70 and loaded with mitomycin C (MMC-PBCA-NP), a highly effective anticancer drug. When injected into mice, MMC-PBCA-NP accumulated more in the liver than did free MMC. In contrast, MMC-PBCA-NP accumulated less in the heart and kidney than did free MMC. However, when MMC-PBCA-NP and MMC were administered to rabbits bearing VX2 cells implanted into the liver, the antiproliferative effects on the tumor cells of both drugs were similar. Histological analyses indicated that organization of myocardial filaments was disrupted and vacuolization was observed in the MMC treated group, whereas MMC-PBCA-NP treatment did not appear to damage the host's heart. Hydropic degeneration of renal tubular epithelia was observed in the MMC treated group and not in the control group, whereas MMC-PBCA-NP treatment did not appear to damage the host's kidney.

Intraarterial gene delivery in rabbit hepatic tumors: transfection with nonviral vector by using iodized oil emulsion

PURPOSE

To evaluate the feasibility of an iodized oil emulsion that is used for the chemoembolization of hepatocellular carcinoma as a modifier of a nonviral gene transfer system for intraarterial gene delivery in experimentally induced hepatic tumors.

MATERIALS AND METHODS

Experiments were performed in accordance with National Institutes of Health guidelines for the care and use of laboratory animals and were approved by the animal research committee at Seoul National University Hospital. VX2 carcinoma was implanted into the liver of 26 rabbits. Four nonviral gene transfer systems were prepared by using pCMV-luc+ as a reporter gene. The first system consisted of a DNA and polyethylenimine (PEI) complex (n = 7); the second, of a DNA and PEI complex mixed with iopamidol and iodized oil (n = 7); the third, of a DNA and PEI complex mixed with iopamidol (n = 7); and the fourth, of a DNA and PEI complex mixed with iodized oil (n = 5). For the DNA and PEI complex that was mixed with iopamidol and iodized oil, iopamidol was used to stabilize the emulsion. Twenty days after tumor implantation, intraarterial gene delivery was performed by selective catheterization of the hepatic artery. Rabbits were euthanized 24 hours after gene delivery. Luciferase activity was assayed in the tumor, left hepatic lobe, right hepatic lobe, and other organs and was statistically analyzed for comparison between complexes by using the Kruskal-Wallis test.

RESULTS

Luciferase activity in the tumor was significantly higher for the group that received DNA, PEI, iopamidol, and iodized oil than for any other group (Kruskal-Wallis test, P < .05). Luciferase activity in the left hepatic lobe, right hepatic lobe, and other organs was not significantly different between complexes. Selective gene expression in tumor cells was confirmed by means of immunohistochemical analysis for luciferase.

CONCLUSION

It is feasible to use an iodized oil emulsion system for the intratumoral transfection of nonviral vectors in experimentally induced hypervascular hepatic tumors.

Radiosensitization of β-elemene on VX2 carcinoma transplanted on kidney in rabbits in vivo

OBJECTIVE

To investigate the radiosensitization of beta-elemene on VX2 carcinoma transplanted on kidney in rabbits in vivo.

METHODS

The rabbits were all transplanted with VX2 carcinoma on kidney. The appropriate dose of beta-elemene infusion via renal artery for further study on radiosensitization was determined. Then fifty-five rabbits were divided into three groups: untreated group, radiation group and radiation plus beta-elemene-treated group. After corresponding intervention for each group, the tumor volume was measured by ultrasonography and spiral computed tomography. The sensitization enhancement ratio (SER) of beta-elemene was calculated. The pathological change of tumor tissue in kidney was observed by light microscopy and electron transmission microscopy. The apoptotic index was also examined by TdT-mediated dUTP-biotin nick end labeling method.

RESULTS

The most significant radiosensitivity was observed in the radiation plus beta-elemene-treated group with 6 Mev X-ray radiation dose of 3 Gy.Fx(-1).d(-1) x 5 d and beta-elemene dose of 10 mg.kg(-1).d(-1). The average time delayed for tumor growth was obviously longer in the radiation plus beta-elemene-treated group than those in the untreated group and radiation group. The SER of beta-elemene was 1.89. The apoptotic index of tumor cells in the radiation plus beta-elemene-treated group was also significantly higher than those in the untreated group and radiation group.

CONCLUSION

The beta-elemene can enhance the effects of irradiation on VX2 carcinoma transplanted to kidney in rabbits in vivo by inducing apoptosis of tumor cells.

Transcatheter Arterial Embolization with 188Rhenium-HDD–labeled Iodized Oil in Rabbit VX2 Liver Tumor

PURPOSE

To evaluate the antitumor effect of transcatheter arterial embolization (TAE) with use of rhenium 188 HDD (4-hexadecyl 2,2,9,9-tetramethyl-4,7-diaza-1,10-decanethiol)-labeled iodized oil and to compare it with that of transcatheter arterial chemoembolization (TACE) with use of an established chemotherapeutic agent and iodized oil in experimentally induced liver tumor.

MATERIALS AND METHODS

VX2 carcinoma was grown in the livers of 57 rabbits. TAE was performed with (188)Re-HDD-labeled iodized oil (Re-Lp group; n = 21), doxorubicin/iodized oil emulsion (Dx-Lp group; n = 21), and iodized oil alone (n = 15). Sequential conjugated planar imaging was performed for dosimetry of the radioisotope in the Re-Lp group (n = 15). Growth ratio and percentage of viable tumor were estimated by computed tomography and histopathologic examination. Hepatic and hematologic toxicities were evaluated by biochemical analysis.

RESULTS

On conjugated planar imaging, radioactivity was concentrated on the tumor (effective half-life, 16.2 hours), and mean radiation dose to the tumor was 147.7 Gy. The mean growth ratios 1, 2, and 3 weeks after TAE and the percentage of viable tumor in the Re-Lp group (-3.4, -7.6, -11.1, and 0.3%) and the Dx-Lp group (-3.2, -5.3, 29.0, and 2.6%) were significantly lower than the respective values in the iodized oil group (45.5, 145.4, 283.0, and 30.1%; P < .001). However, the differences between the values in the Re-Lp group and those in the Dx-Lp group were not significant (P values of .165-0.497 for growth ratios; P = .134 for percentage of viable tumor). There was similar transient hepatotoxicity in all three groups.

CONCLUSIONS

TAE with (188)Re-HDD-labeled iodized oil has potent antitumor effect in VX2 liver tumor that is comparable with that of TACE with an established chemotherapeutic agent.

Transcatheter arterial chemoembolization with paclitaxel-lipiodol solution in rabbit VX2 liver tumor

PURPOSE

To evaluate the antitumor effects of transcatheter arterial chemoembolization (TACE) with a solution of an anticancer drug (Paclitaxel; Bristol-Myers Squibb, Princeton, NJ) and iodized oil (Lipiodol; Laboratoire Gurerbet, Aulnay-Sous-Bois, France) (hereafter, the solution), as well as intratumor concentration and hepatotoxicity, in experimentally induced liver tumor.

MATERIALS AND METHODS

VX2 carcinoma was grown in livers of 30 rabbits. In 18 rabbits, TACE was performed with the high-dose solution (4 mg anticancer drug and 0.4 mL iodized oil, n = 6), the low-dose solution (1 mg anticancer drug and 0.4 mL iodized oil, n = 6), or iodized oil alone (0.4 mL, n = 6) in a control group. One week later, the growth ratio and residual viable proportion of the tumors were calculated on the basis of findings at spiral computed tomography and histopathologic examination. Hepatic and hematologic toxicities were evaluated by means of biochemical analysis. Differences between the three groups were statistically assessed with the Kruskal-Wallace and Mann-Whitney U tests. The remaining 12 animals were treated with the high-dose solution and serially sacrificed for clarification of chronologic change of concentration of the anticancer drug in liver tissues.

RESULTS

Growth ratios and residual viable proportions of the tumors were significantly lower in the solution groups (high dose, 3.3% +/- 6.2 [mean +/- SD] and 2.8% +/- 3.6, respectively; low dose, 18.7% +/- 7.4 and 12.7% +/- 6.1, respectively) than in the control group (68.3% +/- 12.7 and 31.1% +/- 8.8, respectively) (P <.05). Hepatotoxicity was transient in all but one rabbit, which died 2 days after TACE with substantial biochemical changes. The anticancer drug accumulated in tumor where the concentration peaked at day 3 and returned to levels comparable to those for normal hepatic parenchyma at 7 days after TACE.

CONCLUSION

TACE with the Paclitaxel-Lipiodol solution has dose-dependent antitumor effects without major toxicities in VX2 liver tumor.

A new assay for lipiodol in a tumor using a combination of m-chloroperbenzoic acid-mediated oxidation and the iodo-starch reaction

Lipiodol, an iodine adduct lipid, has been used as a targeting carrier of anticancer drugs in experimental animals and humans. In most studies, the concentrations of the anticancer drugs in tissues and organs have been monitored, but not of the carrier because a simple method for measuring lipiodol in biological organs did not exist. Here we present an analytical method for the quantitative determination of lipiodol in tissue. This method is based on the measurement of iodine released from lipiodol by an oxidative reaction. The released iodine was measured spectrophotometrically by monitoring the iodo-starch reaction. Using this method, we were able to demonstrate the tumor specificity of lipiodol using rabbits bearing VX2 tumors in the liver. The present method is also expected to be applicable to human cancers, such as hepatic and colon cancer.