Nanodrug-enhanced radiofrequency tumor ablation: effect of micellar or liposomal carrier on drug delivery and treatment efficacy

Red blood cell-derived materials for cancer therapy: Construction, distribution, and applications

Cancer has become an increasingly important public health issue owing to its high morbidity and mortality rates. Although traditional treatment methods are relatively effective, they have limitations such as highly toxic side effects, easy drug resistance, and high individual variability. Meanwhile, emerging therapies remain limited, and their actual anti-tumor effects need to be improved. Nanotechnology has received considerable attention for its development and application. In particular, artificial nanocarriers have emerged as a crucial approach for tumor therapy. However, certain deficiencies persist, including immunogenicity, permeability, targeting, and biocompatibility. The application of erythrocyte-derived materials will help overcome the above problems and enhance therapeutic effects. Erythrocyte-derived materials can be acquired via the application of physical and chemical techniques from natural erythrocyte membranes, or through the integration of these membranes with synthetic inner core materials using cell membrane biomimetic technology. Their natural properties such as biocompatibility and long circulation time make them an ideal choice for drug delivery or nanoparticle biocoating. Thus, red blood cell-derived materials are widely used in the field of biomedicine. However, further studies are required to evaluate their efficacy, in vivo metabolism, preparation, design, and clinical translation. Based on the latest research reports, this review summarizes the biology, synthesis, characteristics, and distribution of red blood cell-derived materials. Furthermore, we provide a reference for further research and clinical transformation by comprehensively discussing the applications and technical challenges faced by red blood cell-derived materials in the treatment of malignant tumors.

Combined thermal ablation and liposomal granulocyte-macrophage colony stimulation factor increases immune cell trafficking in a small animal tumor model

PURPOSE

To characterize intratumoral immune cell trafficking in ablated and synchronous tumors following combined radiofrequency ablation (RFA) and systemic liposomal granulocyte-macrophage colony stimulation factor (lip-GM-CSF).

METHODS

Phase I, 72 rats with single subcutaneous R3230 adenocarcinoma were randomized to 6 groups: a) sham; b&c) free or liposomal GM-CSF alone; d) RFA alone; or e&f) combined with blank liposomes or lip-GM-CSF. Animals were sacrificed 3 and 7 days post-RFA. Outcomes included immunohistochemistry of dendritic cells (DCs), M1 and M2 macrophages, T-helper cells (Th1) (CD4+), cytotoxic T- lymphocytes (CTL) (CD8+), T-regulator cells (T-reg) (FoxP3+) and Fas Ligand activated CTLs (Fas-L+) in the periablational rim and untreated index tumor. M1/M2, CD4+/CD8+ and CD8+/FoxP3+ ratios were calculated. Phase II, 40 rats with double tumors were randomized to 4 groups: a) sham, b) RFA, c) RFA-BL and d) RFA-lip-GM-CSF. Synchronous untreated tumors collected at 7d were analyzed similarly.

RESULTS

RFA-lip-GMCSF increased periablational M1, CTL and CD8+/FoxP3+ ratio at 3 and 7d, and activated CTLs 7d post-RFA (p<0.05). RFA-lip-GMSCF also increased M2, T-reg, and reduced CD4+/CD8+ 3 and 7d post-RFA respectively (p<0.05). In untreated index tumor, RFA-lip-GMCSF improved DCs, M1, CTLs and activated CTL 7d post-RFA (p<0.05). Furthermore, RFA-lip-GMSCF increased M2 at 3 and 7d, and T-reg 7d post-RFA (p<0.05). In synchronous tumors, RFA-BL and RFA-lip-GM-CSF improved DC, Th1 and CTL infiltration 7d post-RFA.

CONCLUSION

Systemic liposomal GM-CSF combined with RFA improves intratumoral immune cell trafficking, specifically populations initiating (DC, M1) and executing (CTL, FasL+) anti-tumor immunity. Moreover, liposomes influence synchronous untreated metastases increasing Th1, CTL and DCs infiltration.

Myofibroblasts: A key promoter of tumorigenesis following radiofrequency tumor ablation

Radiofrequency ablation (RFA) of intrahepatic tumors induces distant tumor growth through activation of interleukin 6/signal transducer and activator of transcription 3 (STAT3)/hepatocyte growth factor (HGF)/tyrosine-protein kinase Met (c-MET) pathway. Yet, the predominant cellular source still needs to be identified as specific roles of the many types of periablational infiltrating immune cells requires further clarification. Here we report the key role of activated myofibroblasts in RFA-induced tumorigenesis and successful pharmacologic blockade. Murine models simulating RF tumorigenic effects on a macrometastatic tumor and intrahepatic micrometastatic deposits after liver ablation and a macrometastatic tumor after kidney ablation were used. Immune assays of ablated normal parenchyma demonstrated significantly increased numbers of activated myofibroblasts in the periablational rim, as well as increased HGF levels, recruitment other cellular infiltrates; macrophages, dendritic cells and natural killer cells, HGF dependent growth factors; fibroblast growth factor-19 (FGF-19) and receptor of Vascular Endothelial Growth Factor-1 (VEGFR-1), and proliferative indices; Ki-67 and CD34 for microvascular density. Furthermore, macrometastatic models demonstrated accelerated distant tumor growth at 7d post-RFA while micrometastatic models demonstrated increased intrahepatic deposit size and number at 14 and 21 days post-RFA. Multi-day atorvastatin, a selective fibroblast inhibitor, inhibited RFA-induced HGF and downstream growth factors, cellular markers and proliferative indices. Specifically, atorvastatin treatment reduced cellular and proliferative indices to baseline levels in the micrometastatic models, however only partially in macrometastatic models. Furthermore, adjuvant atorvastatin completely inhibited accelerated growth of macrometastasis and negated increased micrometastatic intrahepatic burden. Thus, activated myofibroblasts drive RF-induced tumorigenesis at a cellular level via induction of the HGF/c-MET/STAT3 axis, and can be successfully pharmacologically suppressed.

Engineering nanomedicines to inhibit hypoxia-inducible Factor-1 for cancer therapy

Hypoxia-inducible factor-1 (HIF-1), an essential promoter of tumor progression, has attracted increasing attention as a therapeutic target. In addition to hypoxic cellular conditions, HIF-1 activation can be triggered by cancer treatment, which causes drug tolerance and therapeutic failure. To date, a series of effective strategies have been explored to suppress HIF-1 function, including silencing the HIF-1α gene, inhibiting HIF-1α protein translation, degrading HIF-1α protein, and inhibiting HIF-1 transcription. Furthermore, nanoparticle-based drug delivery systems have been widely developed to improve the stability and pharmacokinetics of HIF-1 inhibitors or achieve HIF-1-targeted combination therapies as a nanoplatform. In this review, we summarize the current literature on nanomedicines targeting HIF-1 to combat cancer and discuss their potential for future development.

Image-guided locoregional non-intravascular interventional treatments for hepatocellular carcinoma: Current status

Hepatocellular carcinoma (HCC) is one of the most deadly and frequent cancers worldwide, although great advancement in the treatment of this malignancy have been made within the past few decades. It continues to be a major health issue due to an increasing incidence and a poor prognosis. The majority of patients have their HCC diagnosed at an intermediate or advanced stage in theUSA or China. Curative therapy such as surgical resection or liver transplantation is not considered anoption of treatment at these stages.

Transarterial chemoembolization (TACE), the most widely used locoregional therapeutic approach, used to be the mainstay of treatment for cases with unresectable cancer entities. However, for those patients with hypovascular tumors or impaired liver function reserve, TACE is a suboptimal treatment option. For example, embolization does not result in complete coverage of a hypovascular tumor, and may rather promotes postoperative tumor recurrence, or leave residual tumor, in these TACE-resistance patients. In addition, TACE carries a higher risk of hepatic decompensation in patients with poor liver function or reserve.

Non-vascular interventional locoregional therapies for HCC include radiofrequency ablation (RFA), microwave ablation (MWA), high-intensity focused ultrasound (HIFU), laser-induced thermotherapy (LITT), cryosurgical ablation (CSA), irreversible Electroporation (IRE), percutaneous ethanol injection (PEI), and brachytherapy. Recent advancements in these techniques have significantly improved the treatment efficacy of HCC and expanded the population of patients who qualify for treatment. This review embraces the current status of imaging-guided locoregional non-intravascular interventional treatments for HCCs, with a primary focus on the clinical evaluation and assessment of the efficacy of combined therapies using these interventional techniques.

Recent Advances in Liposomal Drug Delivery System of Quercetin for Cancer Targeting: A Mechanistic Approach

Quercetin (QT, 3,3',4',5,7-pentahydroxyflavone), is a natural flavonoid with nutritional value and acts as a potential free-radical scavenger (antioxidant). QT has also been explored for its anti-cancer as well as anti-proliferative activities against numerous cancerous cells. Moreover, QT exhibits significant pro-apoptotic activity against tumor cells and is well established to control the growth of different carcinoma cells at various phases of the cell cycle. Hence, it can reduce the burden of human solid cancer and metastasis. Both these activities have been established in a diverse class of human cell lines in-vitro as well as in animal models (in-vivo). Apart from the promising therapeutic activities of QT molecule, their applications have been limited due to some major concerns, including low oral bioavailability and poor aqueous solubility. Also, rapid gastrointestinal digestion of QT seems to be a key barrier for its clinical translations for oral drug delivery in conventional dosage form. Henceforth, to overcome these drawbacks, QT is loaded with liposomal systems, which exhibit promising outcomes in the upregulation of QT by the epithelial system and also improved its targeting at the site of action. Furthermore, Liposomes based Drug Delivery Systems (LDDS) have showed significant therapeutic activity with conjugated drug moiety and exhibit safety, biocompatibility, biodegradability, and mitigated toxicity despite having certain limitations associated with physiological and biological barriers. Herein, in this review, we have focused on the mechanism related with the chemotherapeutic activity of QT and also discussed the promising activity of QT-loaded LDDS as a potent chemotherapeutic agent for cancer therapy.

Stress Conditions Induced by Locoregional Therapies Stimulate Enrichment and Proliferation of Liver Cancer Stem Cells

PURPOSE

This study tested the hypothesis that stress conditions that simulated percutaneous thermal ablation (PTA), transarterial embolization (TAE), or transarterial chemoembolization stimulated enrichment of hepatocellular carcinoma (HCC) cancer stem cells (hCSCs) and that hCSC inhibitors can suppress this effect.

MATERIALS AND METHODS

Human HCC cell lines HepG2 and PLC/PRF/5 were subjected to a 46.5°C heat bath for 10 minutes or to 1% hypoxia for 72 hours without fetal bovine serum and with or without doxorubicin. Cells were then treated with a β-catenin inhibitor (FH535 or XAV939), a PI3 kinase inhibitor (Ly294002), or niclosamide, a US Food and Drug Administration-approved antihelminthic drug that acts as a mitochondrial decoupler and mixed inhibitor. Surviving cells were analyzed for hCSC markers by flow cytometry, for stemness by colony-forming assay or sphere-forming assay, and for proliferative capacity by MTT assay (where MTT is 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide). Expression of proteins related to CSC renewal and proliferation were analyzed by immunoblotting and immunostaining.

RESULTS

Conditions that simulated PTA, TAE, and transarterial chemoembolization resulted in an enrichment of cells bearing hCSC markers (CD133, CD44, and EpCAM). Cells surviving heat stress exhibited higher colony- or sphere-forming capacity and a greater proliferative state. These effects could be suppressed by niclosamide and inhibitors of β-catenin and PI3 kinase.

CONCLUSIONS

Stress conditions induced by locoregional therapies stimulated hCSC enrichment and proliferation, which could be suppressed by niclosamide and inhibitors of pathways important for hCSC renewal. Future studies will determine whether combining locoregional therapies with adjuvant hCSC inhibitors reduces HCC recurrence.

Radiofrequency ablation (RFA)-induced systemic tumor growth can be reduced by suppression of resultant heat shock proteins

PURPOSE

To determine the role of hepatic radiofrequency ablation (RFA) heating parameters and their activation of heat shock proteins (HSPs) in modulating distant tumor growth.

METHODS AND MATERIALS

First, to study the effects of RFA dose on distant tumor growth, rats with subcutaneous R3230 adenocarcinoma (10 ± 1 mm) were assigned to 3 different hepatic RF doses (60 °C × 10 min, 70 °C × 5 min or 90 °C × 2 min) that induced identical sized ablation or sham (n = 6/arm). Post-RFA tumor growth rates, cellular proliferation (Ki-67) and microvascular density (MVD) were compared at 7d. Next, the effect of low and high power doses on local HSP70 expression and cellular infiltration (α-SMA + myofibroblasts and CD68 + macrophages), cytokine (IL-6) and growth factor (HGF and VEGF) expression was assessed. Finally, 60 °C × 10 min and 90 °C × 2 min RFA were combined with anti-HSP micellar quercetin (MicQ, 2 mg/ml). A total of 150 animals were used.

RESULTS

Lower RF heating (70 °C × 5 min and 60 °C × 10 min) resulted in larger distant tumors at 7d (19.2 ± 0.8 mm for both) while higher RF heating (90 °C × 2) led to less distant tumor growth (16.7 ± 1.5 mm, p < .01 for both), though increased over sham (13.5 ± 0.5 mm, p < .01). Ki-67 and MVD correlated with tumor growth (p < .01 for all). Additionally, lower dose 60 °C × 10 min hepatic RFA had more periablational HSP70 compared to 90 °C × 2 min (rim: 1.106 ± 163 µm vs. 360 ± 18 µm, p < .001), with similar trends for periablational α-SMA, CD68 and CDC47 (p < .01 for all). Anti-HSP70 MicQ blocked distant tumor growth for lower dose (60 °C × 10: RF/MicQ 14.6 ± 0.4 mm vs. RF alone: 18.1 ± 0.4 mm, p < .01) and higher dose RFA (90 °C × 2 min: RF/MicQ 14.6 ± 0.5 mm vs. RF alone: 16.4 ± 0.7 mm, p < .01).

CONCLUSION

Hepatic RF heating parameters alter periablational HSP70, which can influence and stimulate distant tumor growth. Modulation of RF heating parameters alone or in combination with adjuvant HSP inhibition can reduce unwanted, off-target systemic tumorigenic effects.

Rabbit model to simulate the residual conduction gaps after radiofrequency ablation on the anterior wall of left atrial appendage

PURPOSE

Radiofrequency ablation (RFA) is widely used to treat patients with atrial fibrillation (AF), but its recurrence rate is still high mainly due to pulmonary vein reconnection and residual conduction gaps. We aim to establish a rabbit model to simulate the residual conduction gaps after ablation.

METHODS

Sixty-nine adult New Zealand white rabbits were randomly assigned to six groups. RFA on the anterior wall of left atrial appendage (LAA) were performed with the ablation power from 6 to 21 W. The electrophysiological pacing and mapping technology was used to evaluate the bidirectional conduction of LAA. Histological study and fluorescence techniques were used to evaluate the effect of RFA and the accumulation of drug-loaded liposome on the loop ablation lesions of LAA.

RESULTS

Typical loop ablation lesions of LAA could be observed in vivo and vitro of rabbit models. Histological evaluation revealed coagulative necrosis on the loop ablation lesions. Electrical conduction between inside and outside loop lesions recovered after 1 or 2 weeks after initial unidirectional conduction block. The recurrence rates were significantly different among six groups with varying ablation powers (p < 0.05). Compared with exit conduction block, entrance conduction block was significantly different at 5 min after ablation (p = 0.02). IR-775-loaded liposomes were accumulated on the loop ablation lesions at 48 h after RFA.

CONCLUSIONS

RFA associated with electrophysiological pacing and mapping technology successfully established a novel rabbit model to simulate the residual conduction gaps after RFA.

Focused ultrasound: tumour ablation and its potential to enhance immunological therapy to cancer

Various kinds of image-guided techniques have been successfully applied in the last years for the treatment of tumours, as alternative to surgical resection. High intensity focused ultrasound (HIFU) is a novel, totally non-invasive, image-guided technique that allows for achieving tissue destruction with the application of focused ultrasound at high intensity. This technique has been successfully applied for the treatment of a large variety of diseases, including oncological and non-oncological diseases. One of the most fascinating aspects of image-guided ablations, and particularly of HIFU, is the reported possibility of determining a sort of stimulation of the immune system, with an unexpected "systemic" response to treatments designed to be "local". In the present article the mechanisms of action of HIFU are described, and the main clinical applications of this technique are reported, with a particular focus on the immune-stimulation process that might originate from tumour ablations.

Dual-Drug Containing Core-Shell Nanoparticles for Lung Cancer Therapy

Late-stage diagnosis of lung cancer occurs ~95% of the time due to late manifestation of its symptoms, necessitating rigorous treatment following diagnosis. Existing treatment methods are limited by lack of specificity, systemic toxicity, temporary remission, and radio-resistance in lung cancer cells. In this research, we have developed a folate receptor-targeting multifunctional dual drug-loaded nanoparticle (MDNP) containing a poly(N-isopropylacrylamide)-carboxymethyl chitosan shell and poly lactic-co-glycolic acid (PLGA) core for enhancing localized chemo-radiotherapy to effectively treat lung cancers. The formulation provided controlled releases of the encapsulated therapeutic compounds, NU7441 - a potent radiosensitizer, and gemcitabine - an FDA approved chemotherapeutic drug for lung cancer chemo-radiotherapy. The MDNPs showed biphasic NU7441 release and pH-dependent release of gemcitabine. These nanoparticles also demonstrated good stability, excellent hemocompatibility, outstanding in vitro cytocompatibility with alveolar Type I cells, and dose-dependent caveolae-mediated in vitro uptake by lung cancer cells. In addition, they could be encapsulated with superparamagnetic iron oxide (SPIO) nanoparticles and visualized by MRI in vivo. Preliminary in vivo results demonstrated the low toxicity of these particles and their use in chemo-radiotherapy to effectively reduce lung tumors. These results indicate that MDNPs can potentially be used as nano-vehicles to provide simultaneous chemotherapy and radiation sensitization for lung cancer treatment.

Targeting STAT3 to Suppress Systemic Pro-Oncogenic Effects from Hepatic Radiofrequency Ablation

Purpose To (a) identify key expressed genes in the periablational rim after radiofrequency ablation (RFA) and their role in driving the stimulation of distant tumor growth and (b) use adjuvant drug therapies to block key identified mediator(s) to suppress off-target tumorigenic effects of hepatic RFA. Materials and Methods This institutional animal care and use committee-approved study was performed in C57BL6 mice (n = 20) and F344 rats (n = 124). First, gene expression analysis was performed in mice after hepatic RFA or sham procedure; mice were sacrificed 24 hours to 7 days after treatment. Data were analyzed for differentially expressed genes (greater than twofold change) and their functional annotations. Next, animals were allocated to hepatic RFA or sham treatment with or without STAT3 (signal transducer and activator of transcription 3) inhibitor S3I-201 for periablational phosphorylated STAT3 immunohistochemistry analysis at 24 hours. Finally, animals with subcutaneous R3230 adenocarcinoma tumors were allocated to RFA or sham treatment with or without a STAT3 inhibitor (S3I-201 or micellar curcumin, eight arms). Outcomes included distant tumor growth, proliferation (Ki-67 percentage), and microvascular density. Results At 24 hours, 217 genes had altered expression (107 upregulated and 110 downregulated), decreasing to 55 genes (27 upregulated and 28 downregulated) and 18 genes (four upregulated, 14 downregulated) at 72 hours and 7 days, respectively. At 24 hours, STAT3 occurred in four of seven activated pathways associated with pro-oncogenic genes at network analysis. Immunohistochemistry analysis confirmed elevated periablational phosphorylated STAT3 24 hours after RFA, which was suppressed with S3I-201 (percentage of positive cells per field: 31.7% ± 3.4 vs 3.8% ± 1.7; P < .001). Combined RFA plus S3I-201 reduced systemic distant tumor growth at 7 days (end diameter: 11.8 mm ± 0.5 with RFA plus S3I-201, 19.8 mm ± 0.7 with RFA alone, and 15 mm ± 0.7 with sham procedure; P < .001). STAT3 inhibition with micellar curcumin also suppressed postablation stimulation of distant tumor growth, proliferation, and microvascular density (P < .01). Conclusion Gene expression analysis identified multiple pathways upregulated in the periablational rim after hepatic RFA, of which STAT3 was active in four of seven. Postablation STAT3 activation is linked to increased distant tumor stimulation and can be suppressed with adjuvant STAT3 inhibitors. ^© RSNA, 2017.

Tumor-penetrating Peptide-integrated Thermally Sensitive Liposomal Doxorubicin Enhances Efficacy of Radiofrequency Ablation in Liver Tumors

Purpose To investigate the role of a tumor-penetrating peptide (internalizing CRGDRGPDC [iRGD])-integrated thermally sensitive liposomal (TSL) doxorubicin (DOX) in combination with radiofrequency (RF) ablation of liver tumors in an animal model. Materials and Methods Approval from the institutional animal care and use committee was obtained. Characterization of iRGD-TSL-DOX was performed in vitro. Next, H22 liver adenocarcinomas were implanted in 138 mice in vivo. The DOX accumulation and cell apoptosis of iRGD-TSL-DOX and TSL-DOX with or without RF were evaluated (n = 5) at different time points after treatment with quantitative analysis or pathologic staining. Mice bearing tumors were randomized into the following six groups (each group, eight mice): no treatment, iRGD-TSL-DOX, TSL-DOX, RF alone, RF ablation followed by TSL-DOX at 30 minutes (TSL-DOX combined with RF), and RF ablation followed by iRGD-TSL-DOX (iRGD-TSL-DOX combined with RF). Kaplan-Meier method was used to estimate the survival curves and log-rank test was used for comparison with statistical software. Results DOX encapsulation efficiency in iRGD-TSL-DOX was 97.5% ± 1.3 (standard deviation) with temperature-dependent drug release capability confirmed in vitro. In vivo, the iRGD-TSL-DOX group had overall higher DOX concentration in the tumor and had maximal difference at 24 hours compared with TSL-DOX group (2.7-fold). RF caused more intense cell apoptosis at 24 hours (median, 65% vs 21%, respectively; P < .001). For end-point survival, the iRGD-TSL-DOX combined with RF group had better survival (median, 32 days) than TSL-DOX combined with RF (median, 27 days; P = .035) or RF alone (median, 21 days; P < .001). Conclusion Conjugation to iRGD helped to improve intratumoral DOX accumulation and further enhanced the activity of TSL-DOX in RF ablation of liver tumors. ^© RSNA, 2017 Online supplemental material is available for this article.

Strategies for improving the intratumoral distribution of liposomal drugs in cancer therapy

INTRODUCTION

A major limitation of current liposomal cancer therapies is the inability of liposome therapeutics to penetrate throughout the entire tumor mass. This inhomogeneous distribution of liposome therapeutics within the tumor has been linked to treatment failure and drug resistance. Both liposome particle transport properties and tumor microenvironment characteristics contribute to this challenge in cancer therapy. This limitation is relevant to both intravenously and intratumorally administered liposome therapeutics.

AREAS COVERED

Strategies to improve the intratumoral distribution of liposome therapeutics are described. Combination therapies of intravenous liposome therapeutics with pharmacologic agents modulating abnormal tumor vasculature, interstitial fluid pressure, extracellular matrix components, and tumor associated macrophages are discussed. Combination therapies using external stimuli (hyperthermia, radiofrequency ablation, magnetic field, radiation, and ultrasound) with intravenous liposome therapeutics are discussed. Intratumoral convection-enhanced delivery (CED) of liposomal therapeutics is reviewed.

EXPERT OPINION

Optimization of the combination therapies and drug delivery protocols are necessary. Further research should be conducted in appropriate cancer types with consideration of physiochemical features of liposomes and their timing sequence. More investigation of the role of tumor associated macrophages in intratumoral distribution is warranted. Intratumoral infusion of liposomes using CED is a promising approach to improve their distribution within the tumor mass.

Mitochondrial Delivery of Therapeutic Agents by Amphiphilic DNA Nanocarriers

The first example of mitochondrial delivery of the anticancer drug doxorubicin (Dox) is presented by lipid-functionalized DNA nanocages (LNCs). Dox localized in mitochondria induces significant cytotoxicity and cellular apoptosis in MCF-7 compared with Dox localized in lysosomes. These results suggest that LNC has the potential to be an outstanding tool in the treatment of specific organelle-related diseases such as cancers.

Does Thermosensitive Liposomal Vinorelbine Improve End-Point Survival after Percutaneous Radiofrequency Ablation of Liver Tumors in a Mouse Model?

Purpose To investigate the role of thermosensitive liposome-encapsulated vinorelbine (Thermo-Vin) in combined radiofrequency (RF) ablation of liver tumors. Materials and Methods Approval from the institutional animal care and use committee was obtained before this study. First, the anticancer efficacy of Thermo-Vin was assessed in vitro (H22 cells) for 72 hours at 37°C or 42°C. Next, 203 H22 liver adenocarcinomas were implanted in 191 mice for in vivo study. Tumors were randomized into seven groups: (a) no treatment, (b) treatment with RF ablation alone, (c) treatment with RF ablation followed by free vinorelbine (Free-Vin) at 30 minutes, (d) treatment with RF ablation followed by empty liposomes (Empty-Lip+RF), (e) treatment with RF ablation followed by Thermo-Vin (5 mg/kg), (f) treatment with RF ablation followed by Thermo-Vin (10 mg/kg), and (g) treatment with RF ablation followed by Thermo-Vin (20 mg/kg). Tumor destruction areas and pathologic changes were compared for different groups at 24 and 72 hours after treatment. Kaplan-Meier analysis was used to compare end-point survival (tumor < 30 mm in diameter). Additionally, the effect of initial tumor size on long-term outcome was analyzed. Results In vitro, both Free-Vin and Thermo-Vin dramatically inhibited H22 cell viability at 24 hours. Likewise, in vivo, 10 mg/kg Thermo-Vin+RF ablation increased tumor destruction compared with RF ablation (P = .001). Intratumoral vinorelbine accumulation with Thermo-Vin+RF increased 15-fold compared with Free-Vin alone. Thermo-Vin substantially increased apoptosis at the coagulation margin and suppressed cellular proliferation in the residual tumor (P < .001). The Thermo-Vin+RF study arm also had better survival than the arm treated with RF ablation alone (mean, 37.6 days ± 20.1 vs 23.4 days ± 5.0; P = .001), the arm treated with Free-Vin+RF (23.3 days ± 1.2, P = .002), or the arm treated with Empty-Lip+RF (20.8 days ± 0.4, P < .001) in animals with medium-sized (10-12-mm) tumors. No significant difference in end-point survival was noted in the treatment arms with large or small tumors. Conclusion Thermo-Vin can effectively increase tumor destruction and improve animal survival. End-point survival is most affected in animals with medium-sized tumors, suggesting that combination therapy should be tailored to tumor size and the expected volume of ablation of the device used. (©) RSNA, 2016 Online supplemental material is available for this article.

Enhanced Cytotoxicity of Folic Acid-Targeted Liposomes Co-Loaded with C6 Ceramide and Doxorubicin: In Vitro Evaluation on HeLa, A2780-ADR, and H69-AR Cells

Current research in cancer therapy is beginning to shift toward the use of combinational drug treatment regimens. However, the efficient delivery of drug combinations is governed by a number of complex factors in the clinical setting. Therefore, the ability to synchronize the pharmacokinetics of the individual therapeutic agents present in combination not only to allow for simultaneous tumor accumulation but also to allow for a synergistic relationship at the intracellular level could prove to be advantageous. In this work, we report the development of a novel folic acid-targeted liposomal formulation simultaneously co-loaded with C6 ceramide and doxorubicin [FA-(C6+Dox)-LP]. In vitro cytotoxicity assays showed that the FA-(C6+Dox)-LP was able to significantly reduce the IC50 of Dox when compared to that after the treatment with the doxorubicin-loaded liposomes (Dox-LP) as well as the untargeted drug co-loaded (C6+Dox)-LP on HeLa, A2780-ADR, and H69-AR cells. The analysis of the cell cycle distribution showed that while the C6 liposomes (C6-LP) did not cause cell cycle arrest, all the Dox-containing liposomes mediated cell cycle arrest in HeLa cells in the G2 phase at Dox concentrations of 0.3 and 1 μM and in the S phase at the higher concentrations. It was also found that this arrest in the S phase precedes the progression of the cells to apoptosis. The targeted FA-(C6+Dox)-LP were able to significantly enhance the induction of apoptotic events in HeLa cell monolayers as compared to the other treatment groups. Next, using time-lapse phase holographic imaging microscopy, it was found that upon treatment with the FA-(C6+Dox)-LP, the HeLa cells underwent rapid progression to apoptosis after 21 h as evidenced by a drastic drop in the average area of the cells after loss of cell membrane integrity. Finally, upon evaluation in a HeLa spheroid cell model, treatment with the FA-(C6+Dox)-LP showed significantly higher levels of cell death compared to those with C6-LP and Dox-LP. Overall, this study clearly shows that the co-delivery of C6 ceramide and Dox using a liposomal platform significantly correlates with an antiproliferative effect due to cell cycle regulation and subsequent induction of apoptosis and thus warrants its further evaluation in preclinical animal models.

Pluronic F127–chondroitin sulfate micelles prepared through a facile method for passive and active tumor targeting

Micelles based on Pluronic F127 and chondroitin sulfate with targeting properties were fabricated to specifically deliver DOX to tumors.

Radiofrequency ablation-combined multimodel therapies for hepatocellular carcinoma: Current status

Radiofrequency ablation (RFA) is widely accepted as a first-line interventional oncology approach for hepatocellular carcinoma (HCC) and has the advantages of high treatment efficacy and low complication risk. Local control rates equivalent to hepatic resection can be reached by RFA alone when treating small HCCs (<2 cm) in favorable locations. However, local tumor progression and recurrence rates with RFA monotherapy increase sharply when treating larger lesions (>3 cm). To address this clinical problem, recent efforts have focused on multimodel management of HCC by combining RFA with different techniques, including percutaneous ethanol injection, transarterial chemo-embolization, targeted molecular therapy, nanoparticle-mediated therapy, and immunotherapy. The combination strategy indeed leads to better outcomes in comparison to RFA alone. In this article, we review the current status of RFA-combined multimodal therapies in the management of HCC.

Hyperthermia approaches for enhanced delivery of nanomedicines to solid tumors

Drug delivery to solid tumors has received much attention in order to reduce harmful side effects and improve the efficacy of treatment. Different strategies have been utilized with nanoparticle drug delivery systems, or nanomedicines, including passive and active targeting strategies, as well as the incorporation of stimuli sensitivity. Additionally, hyperthermia has been used in combination with such systems to further improve accumulation, localization, penetration, and subsequently efficacy. Localized hyperthermia within the solid tumor tissue can be applied through different mechanisms able to trigger vascular and cellular mechanisms for enhanced delivery of nanomedicines. This review covers the use of nanoparticles in drug delivery, the different methods for inducing localized hyperthermia, combination effects of hyperthermia, and successful strategies for improving the delivery of nanomedicines using hyperthermia.

Systemic siRNA Nanoparticle-Based Drugs Combined with Radiofrequency Ablation for Cancer Therapy

PURPOSE

Radiofrequency thermal ablation (RFA) of hepatic and renal tumors can be accompanied by non-desired tumorigenesis in residual, untreated tumor. Here, we studied the use of micelle-encapsulated siRNA to suppress IL-6-mediated local and systemic secondary effects of RFA.

METHODS

We compared standardized hepatic or renal RFA (laparotomy, 1 cm active tip at 70 ± 2 °C for 5 min) and sham procedures without and with administration of 150 nm micelle-like nanoparticle (MNP) anti-IL6 siRNA (DOPE-PEI conjugates, single IP dose 15 min post-RFA, C57Bl mouse:3.5 ug/100ml, Fisher 344 rat: 20 ug/200 ul), RFA/scrambled siRNA, and RFA/empty MNPs. Outcome measures included: local periablational cellular infiltration (α-SMA+ stellate cells), regional hepatocyte proliferation, serum/tissue IL-6 and VEGF levels at 6-72 hr, and distant tumor growth, tumor proliferation (Ki-67) and microvascular density (MVD, CD34) in subcutaneous R3230 and MATBIII breast adenocarcinoma models at 7 days.

RESULTS

For liver RFA, adjuvant MNP anti-IL6 siRNA reduced RFA-induced increases in tissue IL-6 levels, α-SMA+ stellate cell infiltration, and regional hepatocyte proliferation to baseline (p < 0.04, all comparisons). Moreover, adjuvant MNP anti-IL6- siRNA suppressed increased distant tumor growth and Ki-67 observed in R3230 and MATBIII tumors post hepatic RFA (p<0.01). Anti-IL6 siRNA also reduced RFA-induced elevation in VEGF and tumor MVD (p < 0.01). Likewise, renal RFA-induced increases in serum IL-6 levels and distant R3230 tumor growth was suppressed with anti-IL6 siRNA (p < 0.01).

CONCLUSIONS

Adjuvant nanoparticle-encapsulated siRNA against IL-6 can be used to modulate local and regional effects of hepatic RFA to block potential unwanted pro-oncogenic effects of hepatic or renal RFA on distant tumor.