Non-Invasive Radiofrequency Field Treatment of 4T1 Breast Tumors Induces T-cell Dependent Inflammatory Response.

Previous work using non-invasive radiofrequency field treatment (RFT) in cancer has demonstrated its therapeutic potential as it can increase intratumoral blood perfusion, localization of intravenously delivered drugs, and promote a hyperthermic intratumoral state. Despite the well-known immunologic benefits that febrile hyperthermia can induce, an investigation of how RFT could modulate the intra-tumoral immune microenvironment had not been studied. Thus, using an established 4T1 breast cancer model in immune competent mice, we demonstrate that RFT induces a transient, localized, and T-cell dependent intratumoral inflammatory response. More specifically we show that multi- and singlet-dose RFT promote an increase in tumor volume in immune competent Balb/c mice, which does not occur in athymic nude models. Further leukocyte subset analysis at 24, 48, and 120 hours after a single RFT show a rapid increase in tumoral trafficking of CD4+ and CD8+ T-cells 24 hours post-treatment. Additional serum cytokine analysis reveals an increase in numerous pro-inflammatory cytokines and chemokines associated with enhanced T-cell trafficking. Overall, these data demonstrate that non-invasive RFT could be an effective immunomodulatory strategy in solid tumors, especially for enhancing the tumoral trafficking of lymphocytes, which is currently a major hindrance of numerous cancer immunotherapeutic strategies.

A new mild hyperthermia device to treat vascular involvement in cancer surgery.

Surgical margin status in cancer surgery represents an important oncologic parameter affecting overall prognosis. The risk of disease recurrence is minimized and survival often prolonged if margin-negative resection can be accomplished during cancer surgery. Unfortunately, negative margins are not always surgically achievable due to tumor invasion into adjacent tissues or involvement of critical vasculature. Herein, we present a novel intra-operative device created to facilitate a uniform and mild heating profile to cause hyperthermic destruction of vessel-encasing tumors while safeguarding the encased vessel. We use pancreatic ductal adenocarcinoma as an in vitro and an in vivo cancer model for these studies as it is a representative model of a tumor that commonly involves major mesenteric vessels. In vitro data suggests that mild hyperthermia (41-46 °C for ten minutes) is an optimal thermal dose to induce high levels of cancer cell death, alter cancer cell's proteomic profiles and eliminate cancer stem cells while preserving non-malignant cells. In vivo and in silico data supports the well-known phenomena of a vascular heat sink effect that causes high temperature differentials through tissues undergoing hyperthermia, however temperatures can be predicted and used as a tool for the surgeon to adjust thermal doses delivered for various tumor margins.

The effects of non-invasive radiofrequency electric field hyperthermia on biotransport and biodistribution of fluorescent [60]fullerene derivative in a murine orthotopic model of breast adenocarcinoma.

The aim of this study is to understand the combined and differential biokinetic effects of radiofrequency (RF) electric-field hyperthermia as an adjunctive therapy to [60]fullerene nanoparticle-based drug delivery systems in targeting the micro-vasculature and micro-environments of breast cancer tumors. Intravital microscopy (IVM) is an ideal tool to provide the spatial and temporal resolution needed for quantification in this investigation. The water-soluble and fluorescent [60]fullerene derivative (C60-serPF) was designed to be an amphiphilic nanostructure, which is able to cross several biological membranes and accumulate in tumor tissues by passing through abnormally leaky tumor blood vessels. To elucidate the coupled effects of the highly permeable, but heterogeneous tumor vasculature, with the permeabilizing effects of mild (40-42°C) hyperthermia produced by a local RF field, we controlled variables across tumor and non-tumor mammary gland microvasculature with and without application of RF hyperthermia in each condition. We notice that tumor tissue is characterized by more intense drug extravasation than in contralateral mammary fat pad tissue, which is consistent with enhanced permeability and retention (EPR) effects. The analysis of a permeability parameter (Papp), C60-serPF velocity, and the time of compound influx into the intra- and extra-vascular space suggest that mild RF hyperthermia can improve nanoparticle delivery into tumor tissue.

Optimizing non-invasive radiofrequency hyperthermia treatment for improving drug delivery in 4T1 mouse breast cancer model.

Interactions of high-frequency radio waves (RF) with biological tissues are currently being investigated as a therapeutic platform for non-invasive cancer hyperthermia therapy. RF delivers thermal energy into tissues, which increases intra-tumoral drug perfusion and blood-flow. Herein, we describe an optical-based method to optimize the short-term treatment schedules of drug and hyperthermia administration in a 4T1 breast cancer model via RF, with the aim of maximizing drug localization and homogenous distribution within the tumor microenvironment. This method, based on the analysis of fluorescent dyes localized into the tumor, is more time, cost and resource efficient, when compared to current analytical methods for tumor-targeting drug analysis such as HPLC and LC-MS. Alexa-Albumin 647 nm fluorphore was chosen as a surrogate for nab-paclitaxel based on its similar molecular weight and albumin driven pharmacokinetics. We found that RF hyperthermia induced a 30-40% increase in Alexa-Albumin into the tumor micro-environment 24 h after treatment when compared to non-heat treated mice. Additionally, we showed that the RF method of delivering hyperthermia to tumors was more localized and uniform across the tumor mass when compared to other methods of heating. Lastly, we provided insight into some of the factors that influence the delivery of RF hyperthermia to tumors.

Water-structuring molecules and nanomaterials enhance radiofrequency heating in biologically relevant solutions.

For potential applications in nano-mediated radiofrequency cancer hyperthermia, the nanomaterial under investigation must increase the heating of any aqueous solution in which it is suspended when exposed to radiofrequency electric fields. This should also be true for a broad range of solution conductivities, especially those that artificially mimic the ionic environment of biological systems. Herein we demonstrate enhanced heating of biologically relevant aqueous solutions using kosmotropes and a hexamalonoserinolamide fullerene.

A New Imaging Platform for Visualizing Biological Effects of Non-Invasive Radiofrequency Electric-Field Cancer Hyperthermia.

Herein, we present a novel imaging platform to study the biological effects of non-invasive radiofrequency (RF) electric field cancer hyperthermia. This system allows for real-time in vivo intravital microscopy (IVM) imaging of radiofrequency-induced biological alterations such as changes in vessel structure and drug perfusion. Our results indicate that the IVM system is able to handle exposure to high-power electric-fields without inducing significant hardware damage or imaging artifacts. Furthermore, short durations of low-power (< 200 W) radiofrequency exposure increased transport and perfusion of fluorescent tracers into the tumors at temperatures below 41°C. Vessel deformations and blood coagulation were seen for tumor temperatures around 44°C. These results highlight the use of our integrated IVM-RF imaging platform as a powerful new tool to visualize the dynamics and interplay between radiofrequency energy and biological tissues, organs, and tumors.

Gold nanoparticles stabilized with MPEG-grafted poly(l-lysine): in vitro and in vivo evaluation of a potential theranostic agent.

As the number of diagnostic and therapeutic applications utilizing gold nanoparticles (AuNPs) increases, so does the need for AuNPs that are stable in vivo, biocompatible, and suitable for bioconjugation. We investigated a strategy for AuNP stabilization that uses methoxypolyethylene glycol-graft-poly(l-lysine) copolymer (MPEG-gPLL) bearing free amino groups as a stabilizing molecule. MPEG-gPLL injected into water solutions of HAuCl4 with or without trisodium citrate resulted in spherical (Zav = 36 nm), monodisperse (PDI = 0.27), weakly positively charged nanoparticles (AuNP3) with electron-dense cores (diameter: 10.4 ± 2.5 nm) and surface amino groups that were amenable to covalent modification. The AuNP3 were stable against aggregation in the presence of phosphate and serum proteins and remained dispersed after their uptake into endosomes. MPEG-gPLL-stabilized AuNP3 exhibited high uptake and very low toxicity in human endothelial cells, but showed a high dose-dependent toxicity in epithelioid cancer cells. Highly stable radioactive labeling of AuNP3 with (99m)Tc allowed imaging of AuNP3 biodistribution and revealed dose-dependent long circulation in the blood. The minor fraction of AuGNP3 was found in major organs and at sites of experimentally induced inflammation. Gold analysis showed evidence of a partial degradation of the MPEG-gPLL layer in AuNP3 particles accumulated in major organs. Radiofrequency-mediated heating of AuNP3 solutions showed that AuNP3 exhibited heating behavior consistent with 10 nm core nanoparticles. We conclude that PEG-pPLL coating of AuNPs confers "stealth" properties that enable these particles to exist in vivo in a nonaggregating, biocompatible state making them suitable for potential use in biomedical applications such as noninvasive radiofrequency cancer therapy.

The effects of non-invasive radiofrequency treatment and hyperthermia on malignant and nonmalignant cells.

BACKGROUND: Exposure of biological subjects to electromagnetic fields with a high frequency is associated with temperature elevation. In our recent studies, we reported that non-invasive radiofrequency (RF) treatment at 13.56 MHz with the field ranging from 1 KeV to 20 KeV/m2 inhibits tumor progression in animals with abdominal tumor xenografts and enhances the anticancer effect of chemotherapy. The RF treatment was followed by temperature elevation in tumors to approximately 46 °C during 10 min of exposure. In contrast, the temperature of normal tissues remained within a normal range at approximately 37 °C. Whether all biological effects of RF treatment are limited to its hyperthermic property remains unclear. Here, we compared how RF and hyperthermia (HT) treatments change the proliferation rate, oxygen consumption and autophagy in malignant and nonmalignant cells. METHODS: In the current study, cancer and nonmalignant cells of pancreatic origin were exposed to the RF field or to conventional HT at 46 °C, which was chosen based on our previous in vivo studies of the tumor-specific RF-induced hyperthermia. RESULTS: Only RF treatment caused declines in cancer cell viability and proliferation. RF treatment also affected mitochondrial function in cancer cells more than HT treatment did and, unlike HT treatment, was followed by the elevation of autophagosomes in the cytoplasm of cancer cells. Importantly, the effects of RF treatment were negligible in nonmalignant cells. CONCLUSION: The obtained data indicate that the effects of RF treatment are specific to cancer cells and are not limited to its hyperthermic property.

Hyperthermia inhibits recombination repair of gemcitabine-stalled replication forks.

BACKGROUND: Gemcitabine is a potent nucleoside analogue against solid tumors, but development of drug resistance is a substantial problem. Removal of gemcitabine incorporated into DNA by repair mechanisms may contribute to resistance in chemo-refractory solid tumors. Human hepatocellular carcinoma (HCC) is usually very chemoresistant to gemcitabine. METHODS: We treated HCC in vitro and in vivo (orthotopic murine model with human Hep3B or HepG2 xenografts, 7-10 CB17SCID mice per group) with gemcitabine. The role of homologous recombination repair proteins in repairing stalled replication forks was evaluated with hyperthermia exposure and cell-cycle analysis. The Student t-test was used for two-sample comparisons. Multiple group data were analyzed using one-way analysis of variance. All statistical tests were two-sided. RESULTS: We demonstrated that Mre11-mediated homologous recombination repair of gemcitabine-stalled replication forks is crucial to survival of HCC cells. Furthermore, we demonstrated inhibition of Mre11 by an exonuclease inhibitor or concomitant hyperthermia. In orthotopic murine models of chemoresistant HCC, the Hep3B tumor mass with radiofrequency plus gemcitabine treatment (mean ± SD, 180±91mg) was statistically significantly smaller compared with gemcitabine alone (661±419mg, P = .0063). CONCLUSIONS: This study provides mechanistic understanding of homologous recombination inhibiting-strategies, such as noninvasive radiofrequency field-induced hyperthermia, to overcome resistance to gemcitabine in refractory human solid tumors.

Gold nanoparticles and radiofrequency in experimental models for hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most lethal and chemo-refractory cancers, clearly, alternative treatment strategies are needed. We utilized 10nm gold nanoparticles as a scaffold to synthesize nanoconjugates bearing a targeting antibody (cetuximab, C225) and gemcitabine. Loading efficiency of gemcitabine on the gold nanoconjugates was 30%. Targeted gold nanoconjugates in combination with RF were selectively cytotoxic to EGFR expressing Hep3B and SNU449 cells when compared to isotype particles with/without RF (P<0.05). In animal experiments, targeted gold nanoconjugates halted the growth of subcutaneous Hep3B xenografts in combination with RF exposure (P<0.05). These xenografts also demonstrated increased apoptosis, necrosis and decreased proliferation compared to controls. Normal tissues were unharmed. We have demonstrated that non-invasive RF-induced hyperthermia when combined with targeted delivery of gemcitabine is more effective and safe at dosages ~275-fold lower than the current clinically-delivered systemic dose of gemcitabine. FROM THE CLINICAL EDITOR: In a model of hepatocellular carcinoma, the authors demonstrate that non-invasive RF-induced hyperthermia applied with cetuximab targeted delivery of Au NP-gemcitabine conjugate is more effective and safe at dosages ~ 275-fold lower than the current clinically-used systemic dose of gemcitabine.

Protocols for assessing radiofrequency interactions with gold nanoparticles and biological systems for non-invasive hyperthermia cancer therapy.

Cancer therapies which are less toxic and invasive than their existing counterparts are highly desirable. The use of RF electric-fields that penetrate deep into the body, causing minimal toxicity, are currently being studied as a viable means of non-invasive cancer therapy. It is envisioned that the interactions of RF energy with internalized nanoparticles (NPs) can liberate heat which can then cause overheating (hyperthermia) of the cell, ultimately ending in cell necrosis. In the case of non-biological systems, we present detailed protocols relating to quantifying the heat liberated by highly-concentrated NP colloids. For biological systems, in the case of in vitro experiments, we describe the techniques and conditions which must be adhered to in order to effectively expose cancer cells to RF energy without bulk media heating artifacts significantly obscuring the data. Finally, we give a detailed methodology for in vivo mouse models with ectopic hepatic cancer tumors.

Tumor selective hyperthermia induced by short-wave capacitively-coupled RF electric-fields.

There is a renewed interest in developing high-intensity short wave capacitively-coupled radiofrequency (RF) electric-fields for nanoparticle-mediated tumor-targeted hyperthermia. However, the direct thermal effects of such high-intensity electric-fields (13.56 MHZ, 600 W) on normal and tumor tissues are not completely understood. In this study, we investigate the heating behavior and dielectric properties of normal mouse tissues and orthotopically-implanted human hepatocellular and pancreatic carcinoma xenografts. We note tumor-selective hyperthermia (relative to normal mouse tissues) in implanted xenografts that can be explained on the basis of differential dielectric properties. Furthermore, we demonstrate that repeated RF exposure of tumor-bearing mice can result in significant anti-tumor effects compared to control groups without detectable harm to normal mouse tissues.

Modified cisplatin/interferon α-2b/doxorubicin/5-fluorouracil (PIAF) chemotherapy in patients with no hepatitis or cirrhosis is associated with improved response rate, resectability, and survival of initially unresectable hepatocellular carcinoma.

BACKGROUND: The purpose of this study was to evaluate the factors associated with response rate, resectability, and survival after cisplatin/interferon α-2b/doxorubicin/5-fluorouracil (PIAF) combination therapy in patients with initially unresectable hepatocellular carcinoma. METHODS: The study included 2 groups of patients treated with conventional high-dose PIAF (n = 84) between 1994 and 2003 and those without hepatitis or cirrhosis treated with modified PIAF (n = 33) between 2003 and 2012. Tolerance of chemotherapy, best radiographic response, rate of conversion to curative surgery, and overall survival were analyzed and compared between the 2 groups, and multivariate and logistic regression analyses were applied to identify predictors of response and survival. RESULTS: The modified PIAF group had a higher median number of PIAF cycles (4 versus 2, P = .049), higher objective response rate (36% versus 15%, P = .013), higher rate of conversion to curative surgery (33% versus 10%, P = .004), and longer median overall survival (21.3 versus 10.6 months, P = .002). Multivariate analyses confirmed that positive hepatitis B serology (hazard ratio [HR] = 1.68; 95% confidence interval [CI] = 1.08-2.59) and Eastern Cooperative Oncology Group performance status ≥ 2 (HR = 1.75; 95% CI = 1.04-2.93) were associated with worse survival whereas curative surgical resection after PIAF treatment (HR = 0.15; 95% CI = 0.07-0.35) was associated with improved survival. CONCLUSIONS: In patients with initially unresectable hepatocellular carcinoma, the modified PIAF regimen in patients with no hepatitis or cirrhosis is associated with improved response, resectability, and survival.

Adjuvant chemotherapy with FOLFOX for primary colorectal cancer is associated with increased somatic gene mutations and inferior survival in patients undergoing hepatectomy for metachronous liver metastases.

OBJECTIVE: We hypothesized that metachronous colorectal liver metastases (CLM) have different biology after failure of oxaliplatin (FOLFOX) compared to 5-fluorouracil (5-FU) or no chemotherapy for adjuvant treatment of colorectal cancer (CRC). BACKGROUND: It is unclear whether patients treated with liver resection for metachronous CLM after adjuvant FOLFOX for CRC have worse outcomes than those who received 5-FU or no chemotherapy. METHODS: We identified 341 patients who underwent hepatectomy for metachronous CLM (disease-free interval ≥12 months, 1993-2010). Mass-spectroscopy genotyping for somatic gene mutations in CLM was performed in a subset of 129 patients. RESULTS: Adjuvant treatment for primary CRC was FOLFOX in 77 patients, 5-FU in 169 patients, and no chemotherapy in 95 patients. Node-positive primary was comparable between FOLFOX and 5-FU but lower in the no-chemotherapy group (P < 0.0001). Median metastasis size was smaller in the FOLFOX group (2.5 cm) than in the 5-FU (3.0 cm) or no-chemotherapy (3.5 cm) groups, (P = 0.008) although prehepatectomy chemotherapy utilization, metastases number, and carcinoembryonic antigen levels were similar. Disease-free survival (DFS) and overall survival (OS) rates after hepatectomy were worse in patients treated with adjuvant FOLFOX [DFS at 3 years: 14% vs 38% (5-FU) vs 45% (no-chemo), OS at 3 years: 58% vs 70% (5-FU) vs 84% (no-chemo)]. On multivariate analysis, adjuvant FOLFOX was associated with worse DFS (P < 0.0001) and OS (P < 0.0001). Mutation analysis revealed ≥1 mutations in 57% of patients (27/47) after FOLFOX, 29% (12/41) after 5-FU, and 32% (13/41) after no chemotherapy (P = 0.011). CONCLUSIONS: Adjuvant FOLFOX for primary CRC is associated with a high rate of somatic mutations in liver metastases and inferior outcomes after hepatectomy for metachronous CLM.

Luciferase-based protein denaturation assay for quantification of radiofrequency field-induced targeted hyperthermia: developing an intracellular thermometer.

BACKGROUND: Several studies have reported targeted hyperthermia at the cellular level using remote activation of nanoparticles by radiofrequency waves. To date, methods to quantify intracellular thermal dose have not been reported. In this report we study the relationship between radio wave exposure and luciferase denaturation with and without intracellular nanoparticles. The findings are used to devise a strategy to quantify targeted thermal dose in a primary human liver cancer cell line. METHODS: Water bath or non-invasive external Kanzius RF generator (600 W, 13.56 MHz) was used for hyperthermia exposures. Luciferase activity was measured using a bioluminescence assay and viability was assessed using Annexin V-FITC and propidium iodide staining. Heat shock proteins were analysed using western blot analysis. RESULTS: Duration-dependent luciferase denaturation was observed in SNU449 cells exposed to RF field that preceded measurable loss in viability. Loss of luciferase activity was higher in cetuximab-conjugated gold nanoparticle (C225-AuNP) treated cells. Using a standard curve from water bath experiments, the intracellular thermal dose was calculated. Cells treated with C225-AuNP accumulated 6.07 times higher intracellular thermal dose than the untreated controls over initial 4 min of RF exposure. CONCLUSION: Cancer cells when exposed to an external RF field exhibit dose-dependent protein denaturation. Luciferase denaturation assay can be used to quantify thermal dose delivered after RF exposures to cancer cells with and without nanoparticles.

Stability of antibody-conjugated gold nanoparticles in the endolysosomal nanoenvironment: implications for noninvasive radiofrequency-based cancer therapy.

The use of noninvasive radiofrequency (RF) electric fields as an energy source for thermal activation of nanoparticles within cancer cells could be a valuable addition to the emerging field of nano-mediated cancer therapies. Based on investigations of cell death through hyperthermia, and offering the ability for total-body penetration by RF fields, this technique is thought to complement and possibly outperform existing nano-heat treatments that utilize alternative heat production via optical or magnetic stimuli. However, it remains a challenge to understand fully the complex RF-nanoparticle-intracellular interactions before full system optimization can be engineered. Herein we have shown that liver cancer cells can selectively internalize antibody-conjugated gold nanoparticles (AuNPs) through receptor-mediated endocytosis, with the nanoparticles predominantly accumulating and aggregating within cytoplasmic endolysosomes. After exposure to an external RF field, nonaggregated AuNPs absorbed and dissipated energy as heat, causing thermal damage to the targeted cancer cells. We also observed that RF absorption and heat dissipation is dependent on solubility of AuNPs in the colloid, which is pH dependent. Furthermore, by modulating endolysosomal pH it is possible to prevent intracellular AuNP aggregation and enhance thermal cytotoxicity in hepatocellular cancer cells. FROM THE CLINICAL EDITOR: Gold nanoparticles absorb energy from RF fields and can exert hyperthermic effects leading to cell death. Combining this known effect with antibody-based targeting of the nanoparticles, selective cancer specific hyperthermia induced cell death therapies can be designed, as demonstrated in this article.

The ongoing history of thermal therapy for cancer.

Through 5,000 years of practice, physicians, surgeons, clergy, or lay people have used thermal therapy to treat mass lesions now known as cancer. The methods have changed dramatically over this time span and certainly the techniques have improved the efficacy and safety. Hyperthermia used in combination with chemotherapy or ionizing radiation continues to improve outcomes. The authors briefly describe the historical role of hyperthermia in cancer care as well as modern expectations based on technological advancements. In particular, the article focuses on the role of hyperthermia for cancers that do not have other, more effective treatments.

Pancreatic carcinoma cells are susceptible to noninvasive radio frequency fields after treatment with targeted gold nanoparticles.

BACKGROUND: Gold and carbon nanoparticles absorb nonionizing radio frequency (RF) energy and release heat. Solid gold nanoparticles are delivered to cancer cells via conjugation with targeting antibodies. Here, 20-nm gold particles were conjugated to cetuximab, which is an epidermal growth factor receptor-1 (EGFR-1) antibody. METHODS: A pancreatic carcinoma cell line that highly expresses EGFR-1, Panc-1, and Cama-1, which is a breast carcinoma cell line that minimally expresses EGFR-1, were treated with 100-nmol/L cetuximab-conjugated gold nanoparticles for 3 h (n = 4). Thirty-six hours later, the dishes were placed in an RF field with a generator power of 200 W for 5 min. After another 36 h, cell injury and death were evaluated with flow cytometry. RESULTS: The targeted cell line Panc-1 had a viability of 46% +/- 12%, whereas the Cama-1 cell had a viability of 92% +/- 2% after RF field exposure (P < .008). Transmission electron microscopy showed gold nanoparticle uptake in Panc-1 cells but negligible uptake by Cama-1 cells. Nontargeted cells do not internalize a sufficient amount of antibody-conjugated gold nanoparticles to induce injury in a noninvasive RF field. CONCLUSION: This technique could be useful in cancer treatment if a cancer-specific antibody is used to localize gold nanoparticles to malignant cells.

Radiofrequency field-induced thermal cytotoxicity in cancer cells treated with fluorescent nanoparticles.

BACKGROUND: Nonionizing radiation, such as radiofrequency field and near infrared laser, induces thermal cytotoxicity in cancer cells treated with gold nanoparticles. Quantum dots are fluorescent semiconducting nanoparticles that were hypothesized to induce similar injury after radiofrequency field irradiation. METHODS: Gold nanoparticles and 2 types of quantum dot (cadmium-selenide and indium-gallium-phosphide) conjugated to cetuximab (C225), a monoclonal antibody against human epidermal growth factor receptor (EGFR)-1, demonstrated concentration-dependent heating in a radiofrequency field. The authors investigated the effect of radiofrequency field exposure after targeted nanoparticle treatment in a coculture of 2 human cancer cell lines that have differential EGFR-1 expression (a high-expressing pancreatic carcinoma, Panc-1, and a low-expressing breast carcinoma, Cama-1). RESULTS: Radiofrequency revealed that Panc-1 or Cama-1 cells not containing gold nanoparticles or quantum dots had a viability of > 92%. The viability of Panc-1 cells exposed to the radiofrequency field after treatment with 50 nM Au-C225 was 39.4% +/- 8.3% without injury to bystander Cama-1 cells (viability was 93.7% +/- 1.0%; P approximately .0006). Panc-1 cells treated with targeted cadmium-selenide quantum dots were only 47.5% viable after radiofrequency field exposure (P< .0001 compared with radiofrequency only Panc-1 control cells). Targeted indium-gallium-phosphide quantum dots decreased Panc-1 viability to 58.2% +/- 3.4% after radiofrequency field exposure (P = approximately .0004 compared with Cama-1 and Panc-1 controls). CONCLUSIONS: The authors selectively induced radiofrequency field cytotoxicity in Panc-1 cells without injury to bystander Cama-1 cells using EGFR-1-targeted nanoparticles, and demonstrated an interesting bifunctionality of fluorescent nanoparticles as agents for both cancer cell imaging and treatment.

Bioengineered arginase I increases caspase-3 expression of hepatocellular and pancreatic carcinoma cells despite induction of argininosuccinate synthetase-1.

BACKGROUND: Hepatocellular and pancreatic carcinomas are often auxotrophic for L-arginine, a semi-essential amino acid. The purpose of this study was to investigate cancer cell death using a significantly more active, cobalt-substituted bioengineered arginase. METHODS: Panc-1, a human pancreatic carcinoma cell line, and Hep 3B, a human hepatocellular carcinoma cell line, were exposed to L-arginase. Flow cytometry was used to measure expression of Ki-67, caspase-3, and argininosuccinate synthetase-1 (ASS-1) 4 days after treatment. An MTT assay measured proliferation. The Student t test determined statistical significance. RESULTS: Viability decreased by 31% +/- 2% for Panc-1 cells (P < .0001) and 34% +/- 1% (P < .0001) for Hep 3B cells after treatment. Both cell lines demonstrated a 4-fold increase activated caspase-3 expression after high dose treatment (P < .01), and 5-fold increase in ASS-1 expression (P < .002). Ki-67 expression did not vary in Hep 3B cells but decreased for Panc-1 cells (P < .015). The 50% inhibitory concentration was 8-fold higher for Panc-1 cells than for Hep 3B cells (P < .03). CONCLUSION: Increased ASS-1 expression by these cells, in order to increase L-arginine concentration, is inadequate, suggesting a mechanism by which arginine depletion can be used in multimodality therapy for arginine-dependent cancers.