Liposomal Doxorubicin Increases Radiofrequency Ablation–induced Tumor Destruction by Increasing Cellular Oxidative and Nitrative Stress and Accelerating Apoptotic Pathways

Abstract

Purpose:To determine if oxidative and nitrative stress and/or apoptosis contribute to increased coagulation when combining radiofrequency (RF) ablation with liposomal doxorubicin. Materials and Methods:Animal care committee approval was obtained. R3230 mammary adenocarcinomas in Fischer rats were treated with either RF ablation ( n = 43), 1 mg of intravenously injected liposomal doxorubicin ( n = 26), or combined therapy ( n = 30) and were compared with control subjects ( n = 11). A subset of animals receiving combination therapy ( n = 24) were treated in the presence or absence of N -acetylcysteine (NAC) administered 24 hours and 1 hour before RF ablation. Tumors were analyzed 2 minutes to 72 hours after treatment to determine the temporal range of response by using immunohistochemical staining of the apoptosis marker cleaved caspase-3, phosphorylated g H2AX , and Results:By 4 hours after RF ablation alone, a 0.48-mm 6 0.13 (standard deviation ) peripheral band with 57.0% 6 7.3 cleaved caspase-3 positive cells was noted at the ablation margin, whereas a 0.73-mm 6 0.18 band with 77.7% 6 6.3 positivity was seen for combination therapy ( P , .03 for both comparisons). Combination therapy caused increased and earlier staining for 4-HNE-modifi ed proteins, 8-OHdG, NT, and g H2AX with colocalization to cleaved caspase-3 staining. A rim of increased HSP70 was identifi ed peripheral to the area of cleaved caspase-3. Parameters of oxidative and nitrative stress were signifi cantly inhibited by NAC 1 hour following RF ablation, resulting in decreased cleaved caspase-3 positivity (0.28-mm 6 0.09 band of 25.9% 6 7.4 positivity vs 0.59-mm 6 0.11 band of 62.9% 6 6.0 positivity, P , .001 for both comparisons). Conclusion:Combining RF ablation with liposomal doxorubicin increases cell injury and apoptosis in the zone of increased coagulation by using a mechanism that involves oxidative and nitrative stress that leads to accelerated apoptosis.q RSNA, 2010

Do Liposomal Apoptotic Enhancers Increase Tumor Coagulation and End-Point Survival in Percutaneous Radiofrequency Ablation of Tumors in a Rat Tumor Model?

“…As an additional control to ensure uniformity of staining, whenever direct comparisons were made, IHC staining was repeated with all relevant comparative slides stained at the same time. Tissues were stained with hematoxylineosin for gross histopathologic analysis and with cleaved caspase-3 (Cell Signaling Technology, Danvers, Mass) for apoptosis and HSP70 (Stressgen HSP70 ELISA kit; Assay Designs, Ann Arbor, Mich) for heat-shock analysis, as previously described ( 28 ).…”

“…The coagulation data for the RF ablation alone and RF ablation-doxorubicin groups were obtained from tumors stored in a tumor bank of the same tumor model treated under similar conditions ( 28 ), whereas the coagulation data for the RF ablationpaclitaxel and paclitaxel-RF ablation groups came from the time course study above. Therefore, an additional 36 tumors were used (groups: no treatment, paclitaxel alone, paclitaxel-doxorubicin, paclitaxel-RF ablation-doxorubicin; n = 3 for sacrifi ce at 4 hours, n = 6 for sacrifi ce at 24 hours).…”

Elevated serum levels of heat shock protein 70 can be detected after radiofrequency ablation

“…Furthermore, neither the volume of the primary site or histological type of the tumor nor the estimated volume of the ablated non-malignant tissue had any apparent impact on the amount of released HSP-70. Since it has been reported that HSP are expressed on the cells in the transition zone (Rai et al 2005) or on a small rim immediately adjacent to the final margin of coagulation (Solazzo et al 2010), we estimated the size of this transition zone by calculating the surface of the necrotic area assuming a spherical form of the necrosis, but here again, no correlation could be found. Schueller et al studied the relation between the energy applied, the tissue necrosis, and the in situ expression of HSP-70 and HSP-90.…”

Chemoradionuclide Therapy with186Re-labeled Liposomal Doxorubicin in Combination with Radiofrequency Ablation for Effective Treatment of Head and Neck Cancer in a Nude Rat Tumor Xenograft Model

“…RF ablation with liposomal doxorubicin not only increases the RF ablationinduced coagulation necrosis and intratumoral accumulation of liposomal doxorubicin but also accelerates apoptosis ( 19,26,27 ). We hypothesized that concordant benefi ts for solid tumor therapy would be obtained by combining RF ablation with liposomes encapsulating both doxorubicin and 186 Re.…”