Manon Buijs

Distribution of Iron Oxide–containing Embosphere Particles after Transcatheter Arterial Embolization in an Animal Model of Liver Cancer: Evaluation with MR Imaging and Implication for Therapy

PURPOSEnTo test whether different-sized iron oxide-containing Embosphere (IOE) particles can be detected by dedicated magnetic resonance (MR) imaging when injected intraarterially in an animal model of liver cancer and whether their distribution could be accurately predicted by MR imaging before confirmation with histopathologic analysis.nnnMATERIALS AND METHODSnTwenty New Zealand White rabbits implanted with VX2 liver tumor were randomly assigned to undergo embolization with 100-300-microm particles (group S; n = 10) or 300-500-microm particles (group L; n = 10). Embolization was performed with the catheter placed in the proper hepatic artery. T2*-weighted multiplanar MR imaging was performed within 24 hours after the procedure to detect paramagnetic IOE susceptibility artifact. MR imaging interpretation parameters included presence of artifact in the artery and/or at the tumor bed. Hematoxylin and eosin- and Prussian blue-stained pathologic slides were also obtained and the presence of IOE was evaluated similarly.nnnRESULTSnThe MR detectability rates for IOEs were 100% in both groups. Paramagnetic susceptibility IOE artifact inside the tumor was detected in 30% of group S animals. On pathologic analysis, IOE particles were detected inside the tumor in 70% of this group. IOEs in group L were found outside the tumor within the hepatic artery on MR imaging and histopathologic study (P < .05).nnnCONCLUSIONSnMR imaging readily detected IOE particles in an animal model of liver cancer regardless of the particle size. The smaller particles (100-300 microm) were delivered inside the tumor or in close proximity to the tumor margin, justifying their use for drug delivery or precise embolization.

Doxorubicin-loaded QuadraSphere microspheres: plasma pharmacokinetics and intratumoral drug concentration in an animal model of liver cancer.

The purpose of this study was to evaluate, in vitro and in vivo, doxorubicin-loaded poly (vinyl alcohol-sodium acrylate) copolymer microspheres [QuadraSphere microspheres (QSMs)] for transcatheter arterial delivery in an animal model of liver cancer. Doxorubicin loading efficiency and release profile were first tested in vitro. In vivo, 15 rabbits, implanted with a Vx-2 tumor in the liver, were divided into three groups of five rabbits each, based on the time of euthanasia. Twenty-five milligrams of QSMs was diluted in 10xa0ml of a 10xa0mg/ml doxorubicin solution and 10xa0ml of nonionic contrast medium for a total volume of 20xa0ml. One milliliter of a drug-loaded QSM solution containing 5xa0mg of doxorubicin was injected into the tumor feeding artery. Plasma doxorubicin and doxorubicinol concentrations, and intratumoral and peritumoral doxorubicin tissue concentrations, were measured. Tumor specimens were pathologically evaluated to record tumor necrosis. As a control, one animal was blandly embolized with plain QSMs in each group. In vitro testing of QSM doxorubicin loadability and release over time showed 82–94% doxorubicin loadability within 2xa0h and 6% release within the first 6xa0h after loading, followed by a slow release pattern. In vivo, the doxorubicin plasma concentration declined at 40xa0min. The peak doxorubicin intratumoral concentration was observed at 3xa0days and remained detectable till the study’s end point (7xa0days). Mean percentage tumor cell death in the doxorubicin QSM group was 90% at 7xa0days and 60% in the bland QSM embolization group. In conclusion, QSMs can be efficiently loaded with doxorubicin. Initial experiments with doxorubicin-loaded QSMs show a safe pharmacokinetic profile and effective tumor killing in an animal model of liver cancer.

Trends in Nontherapeutic Laparotomy Rates in Patients Undergoing Surgical Therapy for Hepatic Colorectal Metastases

Surgery is the treatment of choice in selected patients with hepatic colorectal metastases. Despite improvements in preoperative imaging, patients can undergo unnecessary nontherapeutic laparotomy. The aim of this study was to examine trends in nontherapeutic laparotomy rates in patients undergoing planned surgical therapy for hepatic colorectal metastases. Data from 530 operations (461 patients) undergoing potentially curative surgical therapy for colorectal liver metastases between 1994 and 2005 were analyzed. The incidence of nontherapeutic laparotomy was determined and factors associated with nontherapeutic laparotomy were identified. Overall, 49 nontherapeutic laparotomies were performed (9.2%). Higher nontherapeutic laparotomy rates were seen in patients with multiple metastases and tumor sizexa0>5xa0cm (both Pxa0<xa00.05). Preoperative positron emission tomography (PET) imaging was associated with lower risk of nontherapeutic laparotomy [5.6% versus 12.4%, Pxa0=xa00.009, odds ratio (OR)xa0=xa00.42]. At laparotomy, extrahepatic findings were the reason for nontherapeutic laparotomy in 44.9% of cases. The nontherapeutic laparotomy rate significantly decreased over time (14.9% for 1994–1997 versus 9.6% for 1998–2001 versus 4.7% for 2002–2005; Pxa0=xa00.003). While patients in each time period were similar with regard to tumor specific factors, utilization of PET imaging (Pxa0<xa00.001) as well as resection plus ablation (Pxa0=xa00.004) increased over time. We conclude that prevalence of nontherapeutic laparotomy for patients undergoing surgical exploration for hepatic colorectal metastases has decreased significantly in recent years to less than 5%. The reasons for this trend are probably multifactorial and may include improved preoperative assessment, such as PET imaging, as well as salvage surgical options.

Evaluation of Different Calibrated Spherical Polyvinyl Alcohol Microspheres in Transcatheter Arterial Chemoembolization: VX2 Tumor Model in Rabbit Liver

PURPOSEnTo assess whether porosity and compressibility of calibrated spherical polyvinyl alcohol (PVA) microspheres affect doxorubicin plasma and tumor concentrations after transcatheter arterial chemoembolization (TACE) in a VX2 rabbit model.nnnMATERIALS AND METHODSnFifteen rabbits were divided into three groups of five rabbits each. Three different types of calibrated spherical PVA microspheres with variable levels of porosity and compressibility were blindly evaluated. TACE was performed by injecting a mixture of doxorubicin (5 mg) and iodized oil (0.5 mL) followed by injection of the embolic material (0.3-0.5 mL). Plasma concentrations of doxorubicin and doxorubicinol were analyzed 20, 40, 60, and 120 minutes and 2 days after TACE, and liver tissue and tumor doxorubicin concentrations were measured 2 days after TACE.nnnRESULTSnAll calibrated spherical PVA microspheres showed similar patterns of plasma doxorubicin and doxorubicinol release and tumor concentration of doxorubicin. There were no significant differences of drug levels in either plasma or tumor in each group (P > .05).nnnCONCLUSIONSnAfter TACE in a rabbit model of liver cancer, testing of three different types of spherical PVA microspheres with varying degrees of porosity and compressibility showed no significant differences in the plasma doxorubicin release pattern and tumor doxorubicin uptake.

Considerations for Implantation Site of VX2 Carcinoma into Rabbit Liver

PURPOSEnTo assess whether the implantation site of VX2 carcinoma into rabbit liver affects successful vessel selection for transcatheter arterial interventions.nnnMATERIALS AND METHODSnTwenty-four New Zealand White rabbits were randomly assigned to two groups. All implantations were performed by open laparotomy with minced tumor cells inserted into a 16-gauge Angiocath needle. Group I rabbits (n = 12) had tumor implanted into the left medial lobe of the liver and group II rabbits (n = 12) had tumor implanted into the left lateral lobe. Two weeks after implantation, selective angiography was performed for subsequent chemoembolization, which was part of a different study. Tested variables included maximum tumor diameter, tumor feeding artery size, and tumor vascularity.nnnRESULTSnSuccessful tumor growth was achieved in all rabbits. Selective angiography was possible in 33.3% of rabbits in group I and 66.6% of rabbits in group II (P < .05). Tumor size and vascularity were similar between groups. Mean lengths of tumor feeder arteries from the bifurcation of the left hepatic artery were 4.1 mm +/- 1.2 in group I (left medial lobe) and 10.8 mm +/- 3.0 in group II (left lateral lobe; P < .05). The angulation of the left medial lobar artery (group I) off the left hepatic artery was acute in eight of 12 rabbits (66.6%), but only four of 12 rabbits in group II (33.3%) showed acute angulation of the left lateral lobar artery off the left hepatic artery (P < .05). Mean angiography time was significantly shorter in group II.nnnCONCLUSIONSnFor selective hepatic arterial interventions, the left lateral lobe of the liver may be favorable as an implantation site for VX2 tumors in rabbits.

Percutaneous US-guided implantation of Vx-2 carcinoma into rabbit liver: a comparison with open surgical method.

PURPOSEnTo evaluate technical feasibility and experimental usefulness of percutaneous US-guided implantation of Vx-2 carcinoma in rabbit liver.nnnMATERIALS AND METHODSnForty-eight New Zealand White male rabbits were used. Solid tumor mass of Vx-2 carcinoma was harvested from carrier rabbit, and minced tumor cells were implanted. Twenty-four rabbits underwent percutaneous US-guided tumor implantation, and the same number of rabbits underwent open laparotomy tumor implantation. Tested parameters included technical success, procedural time, amount of anesthesia, recovery time, complications, tumor size, and regional tumor seeding.nnnRESULTSnA new percutaneous US-guided implantation was technically feasible in all rabbits. Evaluation parameters showed that the percutaneous US-guided implantation method is less invasive than the open laparotomy method. Targeting rate for left lateral lobe of implantation site was comparable in both methods (91.7% of percutaneous US-guided; 95.8% in open laparotomy). The success rate of tumor growth in the liver was 100% in both groups. However, in the group with US-guidance, tumor seeding developed more frequently in five of 24 rabbits (20.8%) than in open laparotomy group (2/24, 8.3%). Five rabbits had thoracoabdominal wall needle tract seeding, and two rabbits had tumor seeding at both thoracoabdominal wall and intraperitoneal space.nnnCONCLUSIONSnPercutaneous US-guided implantation of Vx-2 carcinoma in rabbit liver is a less invasive alternative to open laparotomy, achieving equally successful tumor growth in the liver. Although percutaneous US-guidance implantation method may not be considered for long-term survival study design because of the possibility of tumor seeding, it can be considered for nonsurvival study design.

Spontaneous tumor regression in a syngeneic rat model of liver cancer: implications for survival studies.

PURPOSEnTo characterize tumor growth of N1S1 cells implanted into the liver of Sprague-Dawley rats to determine if this model could be used for survival studies. These results were compared with tumor growth after implantation with McA-RH7777 cells.nnnMATERIALS AND METHODSnN1S1 or McA-RH7777 cells were implanted into the liver of Sprague-Dawley rats (n = 20 and n = 12, respectively) using ultrasound (US) guidance, and tumor growth was followed by using US. Serum profiles of 19 cytokines were compared in naive versus tumor-bearing rats.nnnRESULTSnBoth types of tumors were visible on US 1 week after tumor implantation, but the mean tumor volume of N1S1 tumors was larger compared to McA-RH7777 tumors (231 mm(3) vs 82.3 mm(3), respectively). Tumor volumes in both groups continued to increase, reaching means of 289 mm(3) and 160 mm(3) in N1S1 and McA-RH7777 groups, respectively, 2 weeks after tumor implantation. By week 3, tumor volumes had decreased considerably, and six tumors (50%) in the McA-RH7777 had spontaneously regressed, versus two (10%) in the N1S1 group. Tumor volumes continued to decrease over the following 3 weeks, and complete tumor regression of all tumors was seen 5 weeks and 6 weeks after tumor implantation in the McA-RH7777 and N1S1 groups, respectively. In an N1S1-implanted rat, multiple cytokines that have been shown to correlate with the ability of the tumor to survive in a hostile environment were increased by as much as 50%, whereas the average increase in cytokine levels was 90%. These findings suggest that the net cytokine environment favors an antitumor immune response. A similar trend was observed in a rat with a McA-RH7777 tumor, and the increase in cytokine levels was considerably more pronounced, with an average increase of 320%.nnnCONCLUSIONSnThe model of N1S1 cell implantation in the liver of Sprague-Dawley rats is not ideal for survival studies and should only be used with great caution in short-term studies that involve cancer therapies.

Antiglycolytic Therapy Combined with an Image-guided Minimally Invasive Delivery Strategy for the Treatment of Breast Cancer

PURPOSEnThe antiglycolytic agent 3-bromopyruvate (3-BrPA) promotes anticancer effects in multiple tumor models. This study evaluated the therapeutic efficacy of ultrasound (US)-guided intratumoral delivery of 3-BrPA in an orthotopic tumor model of breast cancer.nnnMATERIALS AND METHODSnHuman breast cancer cell line MDA MB 231 was used for in vitro and in vivo studies. The anticancer effect of 3-BrPA was evaluated by viability assay, quantification of adenosine triphosphate (ATP) and lactate levels, and activity of matrix metalloproteinase (MMP)-9. In animal experiments, 15 nude mice with MDA MB 231 breast tumors were divided into three groups for US-guided intratumoral treatment with 1.75 mM 3-BrPA (group 1), 5 mM 3-BrPA (group 2), and saline solution (group 3). Tumor size was measured and subjected to histopathologic examination.nnnRESULTSnIn vitro, treatment with 3-BrPA resulted in a dose-dependent decrease in cell viability. A decrease in ATP and lactate levels, invasion, and MMP9 activity and expression was observed after treatment with concentrations of 3-BrPA that did not affect cell viability. In vivo, a significant difference in tumor volume was observed between 3-BrPA-treated and control animals. At the end of the study, tumor volumes in the 3-BrPA groups were 1,876 mm(3)±346 and 426 mm(3)±180 in the 1.75-mM and 5-mM 3-BrPA groups, respectively, versus 4,447 mm(3)±571 in the control group (P< .05).nnnCONCLUSIONSnUS-guided intratumoral injection of 3-BrPA effectively blocks breast cancer progression in an orthotopic mouse tumor model.

Abstract 4462: Induction of apoptosis by 3-bromopyruvate involves endoplasmic reticulum (ER) stress and overcomes autophagy response in human hepatocellular carcinoma cell line Hep3B

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DCnnBackground: Autophagy is a cellular response to adverse conditions that also plays a role in resistance to chemotherapy in cancer cells. Resistance renders systemic chemotherapy generally ineffective against human hepatocellular carcinoma (HCC). The HCC cell line Hep3B is deficient in key apoptotic regulators (p53, Fas) and shows differential apoptotic response to various chemotherapeutic agents. The antiglycolytic agent, 3-bromopyruvate (3-BrPA) is known to induce cell death in human HCC cell lines and has shown potent antitumor activity. In the current study we investigated the intracellular response of Hep3B cells to 3-BrPA treatment and compared it with another HCC cell line, SK-Hep1. Methods: We examined the intracellular effect of 3-BrPA by measuring endoplasmic reticulum (ER) stress using quantitative RT-PCR (qRT-PCR) and immunoblotting. The ultrastructural changes were observed by electron microscopy (EM). Apoptosis was evaluated by TUNEL assay and caspase-3 activation. Results: 3-BrPA treatment induced ER stress and inhibited protein synthesis in a dose and time dependent manner in both the HCC cell lines. EM revealed that 3-BrPA treatment resulted in the initiation of autophagy in Hep3B cells and apoptotic blebbing in SK-Hep1 cells. However, Hep3B cells overcame the initial autophagic response and finally progressed to apoptosis. Conclusions: SK-Hep1 cells upon 3-BrPA treatment underwent the classic pathway of apoptosis whereas Hep3B cells employed autophagy as a defense mechanism but failed to resist apoptosis. We conclude that 3-BrPA treatment promotes apoptosis in human HCC cell lines irrespective of their differential response associated with the status of key apoptotic regulators.nnCitation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4462.