Simultaneous hyperthermia-chemotherapy effect by arterial injection of Fe(Salen) for femur tumor.

We previously identified a novel nanomagnetic particle, N,N'-bis(salicylidene)ethylenediamine iron [Fe(Salen)]. Fe(Salen) not only shows antitumor effects but also magnetic properties. We found that Fe(Salen) can be used for magnet-guided drug delivery and visualization of accumulated drug by magnetic resonance imaging (MRI) because of its magnetism. In addition, Fe(Salen) can generate heat by itself when exposed to an alternating current magnetic field (AMF), resulting in a hyperthermia effect. Herein, we partly elucidated the antitumor mechanism of Fe(Salen) and carried out an i.v. repeated dose toxicity study to decide the therapeutic amount. Furthermore, we evaluated the antitumor effect of selective intra-arterial injection or i.v. injection of Fe(Salen) by catheter and the hyperthermia effect of Fe(Salen) when exposed to AMF in vivo. We used a rabbit model grafted with VX2 cells (rabbit squamous cell carcinoma) on the right leg. Intra-arterial injection of Fe(Salen) showed a greater antitumor effect than did i.v. injection. The combination of Fe(Salen) intra-arterial injection and AMF exposure showed a greater antitumor effect than did either Fe(Salen) or methotrexate (MTX) without AMF exposure, suggesting that AMF exposure greatly enhanced the antitumor effect of Fe(Salen) by arterial injection by catheter. This is the first report that the effectiveness of Fe(Salen) was evaluated in the point of administration route; that is, selective intra-arterial injection by catheter. Taken together, these results indicate a new administration route; that is, selective arterial injection of Fe(Salen) by catheter, and the development of a new strategy of simultaneous hyperthermia-chemotherapy in the future.

Alternating magnetic field enhances cytotoxicity of Compound C.

We previously reported the efficacy of anti-cancer therapy with hyperthermia using an alternating magnetic field (AMF) and a magnetic compound. In the course of the study, unexpectedly, we found that an AMF enhances the cytotoxicity of Compound C, an activated protein kinase (AMPK) inhibitor, although this compound is not magnetic. Therefore, we examined the cellular mechanism of AMF-induced cytotoxicity of Compound C in cultured human glioblastoma (GB) cells. An AMF (280 kHz, 250 Arms) for 30 minutes significantly enhanced the cytotoxicity of Compound C and promoted apoptosis towards several human GB cell lines in vitro. The AMF also increased Compound C-induced cell-cycle arrest of GB cells at the G2 phase and, thus, inhibited cell proliferation. The AMF increased Compound C-induced reactive oxygen species production. Furthermore, the AMF decreased ERK phosphorylation in the presence of Compound C and suppressed the protective autophagy induced by this compound. The application of an AMF in cancer chemotherapy may be a simple and promising method, which might reduce the doses of drugs used in future cancer treatment and, therefore, the associated side effects.

The iron chelating agent, deferoxamine detoxifies Fe(Salen)-induced cytotoxicity.

Iron-salen, i.e., µ-oxo-N,N'-bis(salicylidene)ethylenediamine iron (Fe(Salen)) was a recently identified as a new anti-cancer compound with intrinsic magnetic properties. Chelation therapy has been widely used in management of metallic poisoning, because an administration of agents that bind metals can prevent potential lethal effects of particular metal. In this study, we confirmed the therapeutic effect of deferoxamine mesylate (DFO) chelation against Fe(Salen) as part of the chelator antidote efficacy. DFO administration resulted in reduced cytotoxicity and ROS generation by Fe(Salen) in cancer cells. DFO (25 mg/kg) reduced the onset of Fe(Salen) (25 mg/kg)-induced acute liver and renal dysfunction. DFO (300 mg/kg) improves survival rate after systematic injection of a fatal dose of Fe(Salen) (200 mg/kg) in mice. DFO enables the use of higher Fe(Salen) doses to treat progressive states of cancer, and it also appears to decrease the acute side effects of Fe(Salen). This makes DFO a potential antidote candidate for Fe(Salen)-based cancer treatments, and this novel strategy could be widely used in minimally-invasive clinical settings.

Hyperthermia and chemotherapy using Fe(Salen) nanoparticles might impact glioblastoma treatment.

We previously reported that µ-oxo N,N'-bis(salicylidene)ethylenediamine iron [Fe(Salen)], a magnetic organic compound, has direct anti-tumor activity, and generates heat in an alternating magnetic field (AMF). We showed that Fe(Salen) nanoparticles are useful for combined hyperthermia-chemotherapy of tongue cancer. Here, we have examined the effect of Fe(Salen) on human glioblastoma (GB). Fe(Salen) showed in vitro anti-tumor activity towards several human GB cell lines. It inhibited cell proliferation, and its apoptosis-inducing activity was greater than that of clinically used drugs. Fe(Salen) also showed in vivo anti-tumor activity in the mouse brain. We evaluated the drug distribution and systemic side effects of intracerebrally injected Fe(Salen) nanoparticles in rats. Further, to examine whether hyperthermia, which was induced by exposing Fe(Salen) nanoparticles to AMF, enhanced the intrinsic anti-tumor effect of Fe(Salen), we used a mouse model grafted with U251 cells on the left leg. Fe(Salen), BCNU, or normal saline was injected into the tumor in the presence or absence of AMF exposure. The combination of Fe(Salen) injection and AMF exposure showed a greater anti-tumor effect than did either Fe(Salen) or BCNU alone. Our results indicate that hyperthermia and chemotherapy with single-drug nanoparticles could be done for GB treatment.

Glutamate Promotes Contraction of the Rat Ductus Arteriosus.

BACKGROUND: Extremely preterm infants frequently have patent ductus arteriosus (PDA). Recent recommendations include immediately beginning amino acid supplementation in extremely preterm infants. However, the effect of amino acids on closure of the ductus arteriosus (DA) remains unknown.Methods and Results:Aminogram results in human neonates at day 2 revealed that the plasma glutamate concentration was significantly lower in extremely preterm infants (<28 weeks' gestation) with PDA than in those without PDA and relatively mature preterm infants (28-29 weeks gestation). To investigate the effect of glutamate on DA closure, glutamate receptor expression in fetal rats was examined and it was found that the glutamate inotropic receptor, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) type subunit 1 (GluR1), mRNA was highly expressed in the DA compared to the aorta on gestational day 19 (preterm) and gestational day 21 (term). GluR1 proteins were co-localized with tyrosine hydroxylase-positive autonomic nerve terminals in the rat and human DA. Intraperitoneal administration of glutamate increased noradrenaline production in the rat DA. A whole-body freezing method demonstrated that glutamate administration induced DA contraction in both preterm (gestational day 20) and term rat fetuses. Glutamate-induced DA contraction was attenuated by the calcium-sensitive GluR receptor antagonist, NASPM, or the adrenergic receptor α1 blocker, prazosin. CONCLUSIONS: These data suggest that glutamate induces DA contraction through GluR-mediated noradrenaline production. Supplementation of glutamate might help to prevent PDA in extremely preterm infants. (Circ J 2016; 80: 2388-2396).

Simultaneous hyperthermia-chemotherapy with controlled drug delivery using single-drug nanoparticles.

We previously investigated the utility of µ-oxo N,N'- bis(salicylidene)ethylenediamine iron (Fe(Salen)) nanoparticles as a new anti-cancer agent for magnet-guided delivery with anti-cancer activity. Fe(Salen) nanoparticles should rapidly heat up in an alternating magnetic field (AMF), and we hypothesized that these single-drug nanoparticles would be effective for combined hyperthermia-chemotherapy. Conventional hyperthermic particles are usually made of iron oxide, and thus cannot exhibit anti-cancer activity in the absence of an AMF. We found that Fe(Salen) nanoparticles induced apoptosis in cultured cancer cells, and that AMF exposure enhanced the apoptotic effect. Therefore, we evaluated the combined three-fold strategy, i.e., chemotherapy with Fe(Salen) nanoparticles, magnetically guided delivery of the nanoparticles to the tumor, and AMF-induced heating of the nanoparticles to induce local hyperthermia, in a rabbit model of tongue cancer. Intravenous administration of Fe(Salen) nanoparticles per se inhibited tumor growth before the other two modalities were applied. This inhibition was enhanced when a magnet was used to accumulate Fe(Salen) nanoparticles at the tongue. When an AMF was further applied (magnet-guided chemotherapy plus hyperthermia), the tumor masses were dramatically reduced. These results indicate that our strategy of combined hyperthermia-chemotherapy using Fe(Salen) nanoparticles specifically delivered with magnetic guidance represents a powerful new approach for cancer treatment.

Hyperthermia generated with ferucarbotran (Resovist®) in an alternating magnetic field enhances cisplatin-induced apoptosis of cultured human oral cancer cells.

Hyperthermia is a promising anti-cancer treatment in which the tissue temperature is increased to 42-45 °C, and which is often used in combination with chemotherapy or radiation therapy. Our aim in the present work was to examine the feasibility of combination therapy for oral cancer with cisplatin and hyperthermia generated with ferucarbotran (Resovist(®); superparamagnetic iron oxide) in an alternating magnetic field (AMF). First, we established that administration of ferucarbotran at the approved dosage for magnetic resonance imaging provides an iron concentration sufficient to increase the temperature to 42.5 °C upon exposure to AMF. Then, we examined the effect of cisplatin combined with ferucarbotran/AMF-induced hyperthermia on cultured human oral cancer cells (HSC-3 and OSC-19). Cisplatin alone induced apoptosis of cancer cells in a dose-dependent manner, as is well known. However, the combination of cisplatin with ferucarbotran/AMF was significantly more effective than cisplatin alone. This result suggests that it might be possible to reduce the clinically effective dosage of cisplatin by administering it in combination with ferucarbotran/AMF-induced hyperthermia, thereby potentially reducing the incidence of serious cisplatin-related side effects. Further work seems justified to evaluate simultaneous thermo-chemotherapy as a new approach to anticancer therapy.

Effect of ascorbic acid on reactive oxygen species production in chemotherapy and hyperthermia in prostate cancer cells.

Cellular reactive oxygen species (ROS) production is increased by both temperature and anticancer drugs. Antioxidants are known to suppress ROS production while cancer patients may take them as dietary supplement during chemotherapy and hyperthermic therapy. We examined changes in ROS production in prostate cancer cells in the presence of various anticancer drugs and antioxidants at different temperatures. ROS production was increased with temperature in cancer cells, but not in normal cells; this increase was potently inhibited by ascorbic acid. ROS production was also increased in the presence of some anticancer drugs, such as vinblastine, but not by others. Dietary antioxidant supplements, such as ß-carotene, showed variable effects. Ascorbic acid potently inhibited ROS production, even in the presence of anticancer drugs, while ß-carotene showed no inhibition. Accordingly, our results suggest that cancer patients should carefully choose antioxidants during their cancer chemotherapy and/or hyperthermic therapy.

Mechanical stress-dependent transcriptional regulation of sarcolipin gene in the rodent atrium.

Sarcolipin, a homologue of phospholamban, regulates Ca2+ uptake through the interaction with sarcoplasmic reticulum Ca2+ ATPase (SERCA) and is predominantly expressed in the atrial muscle. Although the atrial chamber-specific expression of sarcolipin could be primarily regulated at the transcriptional level, the transcriptional regulation remains poorly understood. Since mechanical stress plays an important role in transcriptional regulation of a gene involved in cardiac hypertrophy and remodeling, we generated left-sided or right-sided pressure-overload models by transverse aortic constriction (TAC) in ddY mice or by monocrotaline administration in Wistar rats, respectively. TAC significantly decreased the expression of sarcolipin, SERCA2a, and phospholamban mRNAs in the left atrium (LA) than those in the right atrium (RA). By contrast, monocrotaline administration significantly decreased the expression of sarcolipin, SERCA2a, and phospholamban mRNAs in the RA than those in the LA. The two independent complementary experiments unequivocally demonstrated that mechanical stress down-regulates the transcription of the sarcolipin gene.