Remote Death Certification Using Telemedicine in Japan.

A 92-year-old woman diagnosed with dementia and end-stage gastric cancer received end-of-life care on the island where she lived. Informed consent concerning remote death certification based on the Japanese government's guidelines was obtained from a family member in case a physician was unavailable. A physical examination after cardiopulmonary arrest was conducted, supported by telemedicine and a well-trained registered nurse under remote supervision of the physician who last saw the deceased directly. Death certification was provided accordingly. To our knowledge, this was the first case of remote death certification using telemedicine in Japan.

Residents in a Remote Island Having Family Members in Distant Areas Showed Higher Preference for Place of End-of-Life Care: The Ajishima Study.

INTRODUCTION: To investigate the proportion of those having preferred place for end-of-life care among residents in a remote island and its association with family composition. METHODS: Cross-sectional questionnaire survey was conducted in Ajishima, an island 23 km away from the coast of Ishinomaki City, northeast of Japan. Between October 2017 and February 2018, the questionnaire was distributed to 288 eligible residents and 113 valid responses were analyzed. Primary outcome was whether the subjects had preferred place for end-of-life care. The explanatory variable was family composition defined as whether having family members inside or outside the island [none (In-/Out-), only inside the island (In+/Out-), only outside the island (In-/Out+), and both inside and outside (In+/Out+)]. Poisson regression analysis was used to calculate the prevalence ratios (PRs) and 95% confidence intervals (CIs) of showing preferred place in each group. RESULTS: The proportion of those having preferred place for end-of-life care was 72.6% in total. This rate significantly differed across family composition groups: 67.6%, 40.0%, and 82.9% for In+/Out+, In+/Out-, and In-/Out+ groups, respectively. The PR (95%CI) of having preferred place was 0.66 (0.33, 1.36) and 1.26 (1.01, 1.56) for In+/Out- and In-/Out+ groups, respectively, compared with In+/Out+ group. CONCLUSIONS: This study showed that significantly higher preference for place of end-of-life care was seen among residents who had family members only outside the island compared with those who had families both inside and outside. Health care professionals should consider family compositions when initiating end-of-life discussion to residents in remote areas.

2-Aminophenoxazine-3-one-induced apoptosis via generation of reactive oxygen species followed by c-jun N-terminal kinase activation in the human glioblastoma cell line LN229.

2-Aminophenoxazine-3-one (Phx-3) induces apoptosis in several types of cancer cell lines. However, the mechanism of apoptosis induction by Phx-3 has not been fully elucidated. In this study, we investigated the anticancer effects of Phx-3 in the glioblastoma cell line LN229 and analyzed its molecular mechanism. The results indicated that 6- and 20-h treatment with Phx-3 significantly induced apoptosis in LN229 cells, with downregulation of survivin and XIAP. Both ERK and JNK, which are the members of the MAPK family, were activated after treatment with Phx-3. Inhibition of ERK using the specific inhibitor U0126 blocked the Phx-3-induced apoptosis only in part. However, inhibition of JNK using the specific inhibitor SP600125 completely prevented Phx-3-induced apoptosis and restored the phosphorylation states of ERK to the control levels. Enhanced generation of reactive oxygen species (ROS) was detected after 3-h treatment with Phx-3. In addition, the ROS scavenger melatonin almost completely blocked Phx-3-induced JNK activation and apoptosis. This suggests that JNK activation was mediated by Phx-3-induced ROS generation. Although SP600125 and melatonin completely blocked the reduction of mitochondrial membrane potential after a 3-h treatment with Phx-3, extension of Phx-3 exposure time to 20 h resulted in no cancelation of mitochondrial depolarization by these reagents. These reagents also had little effect on the decreased expression of survivin and XIAP during a 3-20-h exposure to Phx-3. These results indicate that the production of ROS following JNK activation is the main axis of Phx-3-induced apoptosis in LN229 cells for short-term exposure to Phx-3, whereas alternative mechanism(s) appear to be involved in apoptosis induction during long-term exposure to Phx-3.

Prevention of carcinogenesis and development of gastric and colon cancers by 2-aminophenoxazine-3-one (Phx-3): direct and indirect anti-cancer activity of Phx-3.

2-Aminophenoxazine-3-one (Phx-3), an oxidative phenoxazine, exerts strong anticancer effects on various cancer cell lines originating from different organs, in vitro. This article reviews new aspects for the prevention of carcinogenesis and development of gastric and colon cancers by Phx-3, based on the strong anticancer effects of Phx-3 on gastric and colon cancer cell lines (direct anticancer effects of Phx-3 for preventing development of cancer), the bacteriocidal effects of Phx-3 against Helicobacter pylori associated with carcinogenesis of gastric cancer (indirect anticancer effects for preventing carcinogenesis of gastric cancer), and the proapoptotic activity of Phx-3 against human neutrophils involved in the incidence of ulcerative colitis associated with a high colon cancer risk (indirect anticancer effects for preventing carcinogenesis of colon cancer).

Macrolide antibiotics block autophagy flux and sensitize to bortezomib via endoplasmic reticulum stress-mediated CHOP induction in myeloma cells.

The specific 26S proteasome inhibitor bortezomib (BZ) potently induces autophagy, endoplasmic reticulum (ER) stress and apoptosis in multiple myeloma (MM) cell lines (U266, IM-9 and RPMI8226). The macrolide antibiotics including concanamycin A, erythromycin (EM), clarithromycin (CAM) and azithromycin (AZM) all blocked autophagy flux, as assessed by intracellular accumulation of LC3B-II and p62. Combined treatment of BZ and CAM or AZM enhanced cytotoxicity in MM cell lines, although treatment with either CAM or AZM alone exhibited almost no cytotoxicity. This combination also substantially enhanced aggresome formation, intracellular ubiquitinated proteins and induced the proapoptotic transcription factor CHOP (CADD153). Expression levels of the proapoptotic genes transcriptionally regulated by CHOP (BIM, BAX, DR5 and TRB3) were all enhanced by combined treatment with BZ plus CAM, compared with treatment with each reagent alone. Like the MM cell lines, the CHOP+/+ murine embryonic fibroblast (MEF) cell line exhibited enhanced cytotoxicity and upregulation of CHOP and its transcriptional targets with a combination of BZ and one of the macrolides. In contrast, CHOP-/- MEF cells exhibited resistance against BZ and almost completely canceled enhanced cytotoxicity with a combination of BZ and a macrolide. These data suggest that ER stress-mediated CHOP induction is involved in pronounced cytotoxicity. Simultaneously targeting two major intracellular protein degradation systems such as the ubiquitin-proteasome system by BZ and the autophagy-lysosome system by a macrolide antibiotic enhances ER stress-mediated apoptosis in MM cells. This result suggests the therapeutic possibility of using a macrolide antibiotic with a proteasome inhibitor for MM therapy.

Enhancement of cytotoxic and pro-apoptotic effects of 2-aminophenoxazine-3-one on the rat hepatocellular carcinoma cell line dRLh-84, the human hepatocellular carcinoma cell line HepG2, and the rat normal hepatocellular cell line RLN-10 in combination with 2-deoxy-D-glucose.

The cytotoxic and pro-apoptotic effects of a single dose of 2-aminophenoxazine-3-one (Phx-3) or 2-deoxyglucose (2-DG) or of a combined dose of Phx-3 and 2-DG were studied in the rat hepatocellular carcinoma cell line dRLh-84, the human hepatocellular carcinoma cell line HepG2 and the rat normal hepatocellular cell line RLN-10. The number of viable cells decreased in a dose-dependent manner, when dRLh-84, HepG2 or RLN-10 cells were treated with 2-DG (0.5-20 mM) or Phx-3 (1-50 µM) alone at 37˚C for 48 h. When these cells were treated with 10 mM 2-DG and different concentrations of Phx-3, the number of viable cells decreased dose-dependently and in an additive manner for these agents. A single dose of 2 or 10 µM Phx-3 induced apoptotic morphology characterized by nuclear condensation and cell shrinkage in dRLh-84, HepG2 and RLN-10 cells, while a single dose of 10 mM 2-DG did not. When Phx-3 (2 or 10 µM) treatment was combined with 2-DG (10 mM) treatment in these three cell lines, the cells with apoptotic morphology increased extensively, which was confirmed by flow cytometric analysis. In addition, autophagic morphology characterized by cytosolic vacuole formation was significantly increased in the hepatocellular carcinoma cell lines dRLh-84 and HepG2 but not in the normal hepatocellular cell line RLN-10 after a single dose of Phx-3 or 2-DG or a combined dose of Phx-3 and 2-DG. Furthermore, when dRLh-84 and HepG2 cells were treated with Phx-3 alone or a combined dose of Phx-3 and 2-DG, depolarization of the mitochondria was extensive, but that of the normal cell line RLN-10 was not. These results may imply that the mechanism for the apoptosis of hepatocellular carcinoma cells caused by Phx-3 alone or a combined dose of Phx-3 and 2-DG differs from that of the normal cell line RLN-10. The present results demonstrate that Phx-3 alone may be beneficial for targeting liver cancer and that its anticancer activity may be enhanced by 2-DG. However, a combined dose of Phx-3 and 2-DG may exert adverse effects on normal liver cells, as evidenced by the cytotoxic and pro-apoptotic effects of the combined treatment in the rat normal hepatocellular cell line RLN-10.

Clarithromycin enhances bortezomib-induced cytotoxicity via endoplasmic reticulum stress-mediated CHOP (GADD153) induction and autophagy in breast cancer cells.

The specific 26S proteasome inhibitor, bortezomib (BZ) potently induces apoptosis as well as autophagy in metastatic breast cancer cell lines such as MDA-MB-231 and MDA-MB-468. The combined treatment of clarithromycin (CAM) and BZ significantly enhances cytotoxicity in these cell lines. Although treatment with up to 100 µg/ml CAM alone had little effect on cell growth inhibition, the accumulation of autophagosomes and p62 was observed after treatment with 25 µg/ml CAM. This result indicated that CAM blocked autophagy flux. However, the combined treatment of BZ and CAM resulted in more pronounced autophagy induction, as assessed by increased expression ratios of LC3B-II to LC3B-I and clearance of intracellular p62, than treatment with BZ alone. This combination further enhanced induction of the pro-apoptotic transcription factor CHOP (CADD153) and the chaperone protein GRP78. Knockdown of CHOP by siRNA attenuated the death-promoting effect of BZ in MDA-MB-231 cells. A wild-type murine embryonic fibroblast (MEF) cell line also exhibited enhanced BZ-induced cytotoxicity with the addition of CAM, whereas a Chop knockout MEF cell line completely abolished this enhancement and exhibited resistance to BZ treatment. These data suggest that endoplasmic reticulum (ER)-stress mediated CHOP induction is involved in pronounced cytotoxicity by combining these reagents. Simultaneously targeting two major intracellular protein degradation pathways such as the ubiquitin-proteasome system by BZ and the autophagy-lysosome pathway by CAM may improve the therapeutic outcome in breast cancer patients via ER-stress mediated apoptosis.

Selectively induced apoptosis in human neutrophils in the presence of oxidative phenoxazines, 2-amino-4,4α-dihydryo-4α-7H-phenoxazine-3-one and 2-aminophenoxazine-3-one, preceded by decrease of intracellular pH, depolarization of the mitochondria, and inhibition of superoxide generation.

The present research investigated the effect of the oxidative phenoxazines, 2-amino-4,4α-dihydryo-4α-7H-phenoxazine-3-one (Phx-1) and 2-amino-phenoxazine-3-one (Phx-3) on apoptosis induction and apoptosis-related early events in human neutrophils. When Phx-1 or Phx-3 was administered to freshly drawn human blood for 18 h, these phenoxazines caused apoptotic cell death morphologically characterized by condensation of the nucleus in neutrophils, without causing it in lymphocytes and monocytes. Apoptosis, which was detectable by microscopic analysis and by using flow-cytometry, occurred significantly in human neutrophils isolated from freshly drawn blood, 6 h after the administration of 50 µM Phx-1 and Phx-3. After 24 h, every isolated neutrophil treated with Phx-1 or Phx-3 fell into apoptosis or lost its morphology, while many of the neutrophils without these phenoxazines remained alive, with normal morphology. Apoptosis-related early events including a decrease in intracellular pH (pHi) and depolarization of the mitochondria occurred in the isolated neutrophils, 30 min and 6 h after the administration of Phx-1 or Phx-3, respectively. Superoxide generation from the isolated neutrophils mimicked by phorbol myristate acetate (PMA) was very markedly inhibited by 100 µM Phx-1 or Phx-3. This result could be explained, in part, by the fact that the insufficient supply of NADPH (nicotinamide adenine dinucleotide phosphate, reduced form) was caused by pHi decrease in neutrophils treated with Phx-1 or Phx, because NADPH is necessary for NADPH oxidase responsible for generating superoxide in the cells. The present results suggest that Phx-1 and Phx-3 have the capacity of selectively inducing apoptosis in human neutrophils and that these phenoxazines may be useful as specific drugs to induce apoptotic cell death of human neutrophils and thereby prevent inflammation caused by these phagocytic cells.

Involvement of endoplasmic reticulum stress-mediated CHOP (GADD153) induction in the cytotoxicity of 2-aminophenoxazine-3-one in cancer cells.

In this study, 2-aminophenoxazine-3-one (Phx-3) exhibited a potent cell growth inhibitory effect with apoptotic features in a dose-dependent manner in various cancer cell lines tested. Comparison of the expression profiles of endoplasmic reticulum (ER) stress-related genes in U266 multiple myeloma cells after treatment with Phx-3 and the ER stress inducers tunicamycin (TNM) and thapsigargin (TPG) indicated that although TNM and TPG potently induced pro-apoptotic transcription factor CHOP (GADD153) within 8 h of treatment, Phx-3 induced almost no CHOP within 48 h of treatment in U266 cells. However, murine embryonic fibroblast (MEF) cells and other cancer cell lines (e.g. A549 lung cancer cells and HL-60 acute leukemia cells) exhibited up-regulation of CHOP after treatment with Phx-3. The potency of CHOP induction in response to Phx-3 appeared to be partially correlated with the cytotoxic sensitivity of Phx-3 among various cell lines tested. MEF cells derived from CHOP knockout mice were more resistant to Phx-3 than wild-type MEF cells. Since Phx-3 has been shown to induce activation of NF-κB, a transcription factor functioning as a repressor of CHOP, we further treated U266 cells with a combination of Phx-3 and NF-κB inhibitors (e.g. BAY11-7082 or parthenolide). This enhanced cytotoxicity along with up-modulation of CHOP in U266 cells. These data suggest that ER stress-mediated CHOP induction by Phx-3 is involved in the cytotoxic effect. Regulation of CHOP expression appears to be a potent therapeutic target for cancer treatment.

2-Aminophenoxazine-3-one and 2-amino-4,4α-dihydro-4α,7-dimethyl-3H-phenoxazine-3-one cause cellular apoptosis by reducing higher intracellular pH in cancer cells.

We examined intracellular pH (pHi) of ten cancer cell lines derived from different organs and two normal cell lines including human embryonic lung fibroblast cells (HEL) and human umbilical vein endothelial cells (HUVEC) in vitro, and found that pHi of most of these cancer cells was evidently higher (pH 7.5 to 7.7) than that of normal cells (7.32 and 7.44 for HEL and HUVEC, respectively) and that of primary leukemic cells and erythrocytes hitherto reported (≤7.2). Higher pHi in these cancer cells could be related to the Warburg effect in cancer cells with enhanced glycolytic metabolism. Since reversal of the Warburg effect may perturb intracellular homeostasis in cancer cells, we looked for compounds that cause extensive reduction of pHi, a major regulator of the glycolytic pathway and its associated metabolic pathway. We found that phenoxazine compounds, 2-aminophenoxazine-3-one (Phx-3) and 2-amino-4,4α-dihydro-4α,7-dimethyl-3H-phenoxazine-3-one (Phx-1) caused a rapid and drastic dose-dependent decrease of pHi in ten different cancer cells within 30 min, though the extent of the decrease of pHi was significantly larger for Phx-3 (ΔpHi = 0.6 pH units or more for 100 µM Phx-3) than for Phx-1 (ΔpHi = 0.1 pH units or more for 100 µM Phx-1). This rapid and drastic decrease of pHi in a variety of cancer cells caused by Phx-3 and Phx-1 possibly perturbed their intracellular homeostasis, and extensively affected the subsequent cell death, because these phenoxazines exerted dose-dependent proapoptotic and cytotoxic effects on these cells during 72 h incubation, confirming a causal relationship between ΔpHi and cytotoxic effects due to Phx-3 and Phx-1. Phx-3 and Phx-1 also reduced pHi of normal cells including HEL and HUVEC, although they exerted less proapoptotic and cytotoxic effects on these cells than on cancer cells. Drugs such as Phx-3 and Phx-1 that reduce pHi and thereby induce cellular apoptosis might serve as benevolent anticancer drugs.

Combined treatment with bortezomib plus bafilomycin A1 enhances the cytocidal effect and induces endoplasmic reticulum stress in U266 myeloma cells: crosstalk among proteasome, autophagy-lysosome and ER stress.

Bortezomib (BZ), a first line 26S proteasome inhibitor, induces a potent cytocidal effect with caspase-3 activation in multiple myeloma (MM) cell lines. Since IκBα is a substrate of the proteasome, the initial rationale for using BZ in MM has been to inhibit NF-κB. However, BZ rather activated NF-κB activity in U266 cells. BZ induces autophagy as well as endoplasmic reticulum (ER) stress in various cell lines tested. Inhibition of initial autophagosome formation by treatment with either 3-methyladenine or siRNA for LC3B in U266 cells and knockdown of the atg5 gene in a murine embryonic fibroblastic cell line all resulted in attenuation of BZ-induced cell death. In contrast, combined treatment with BZ and bafilomycin A1 (BAF), which is a specific inhibitor of vacuolar-ATPase and is used as an autophagy inhibitor at the late stage, resulted in synergistic cytotoxicity, compared with that by either BZ or BAF alone. BAF treatment also induced ER stress, but the kinetics of inductions of ER stress-related genes [e.g. CHOP (GADD153) and GRP78] completely differed between BZ- and BAF-treatments: BZ induced these ER stress markers within 8 h, whereas treatment with BAF required more than 48 h in U266 cells. In order to synchronize ER stress, we pre-treated U266 cells with BAF for 48 h, followed with BZ for 48 h. The sequential treatment with BAF and BZ induced a further enhanced cytotoxicity, compared with the simultaneous combination of BAF and BZ. These data suggest crosstalk among the ubiquitin-proteasome system, the autophagy-lysosome system, and ER stress. Controlling these interactions and kinetics appears to have important implications for optimizing clinical cancer treatment including MM-therapy.

Rapid decrease of intracellular pH associated with inhibition of Na+/H+ exchanger precedes apoptotic events in the MNK45 and MNK74 gastric cancer cell lines treated with 2-aminophenoxazine-3-one.

The effects of Phx-3 on changes in intracellular pH (pHi) in the MKN45 and MKN74 human gastric cancer cell lines were evaluated in order to determine the mechanism for the proapoptotic effects of 2-aminophenoxazine-3-one (Phx-3) on these cells. Phx-3 (100 µM) reduced pHi in MKN45 from 7.45 to 5.8, and in MKN74 from 7.5 to 6.2 within 1 min of engagement with these cells. Such a decrease of pHi was closely correlated with the dose of this phenoxazine and continued for 4 h. The activity of Na+/H+ exchanger isoform l (NHE1), which is involved in H+ extrusion from the cells, was dose-dependently suppressed by Phx-3 in these cells, and was greatly suppressed in the presence of 100 µM Phx-3. This result indicates that the decrease of pHi in MKN45 and MKN74 cells is closely associated with the inhibition of NHE1 in these cells. The morphology of these cells at 24 h after treatment with Phx-3 indicated shrinkage of the cells and condensation of the nuclear chromatin structure, which are characteristic of the apoptotic events in these gastric cancer cells. Cytotoxicity of Phx-3 against MKN45 and MKN74 cells was extensive because almost all MKN45 cells lost viability at 24 h in the presence of 20 µM Phx-3, and nearly 50% of the MKN74 cells lost viability in the presence of 50 µM Phx-3. These results suggest that rapid and extensive decrease of pHi in human gastric cancer MKN45 and MKN74 cells caused by Phx-3 might disturb intracellular homeostasis, leading to apoptotic and cytotoxic events in these cells. Phx-3 is a good candidate for therapeutics of gastric cancer that is intractable to conventional chemopreventive therapies.

Phenoxazine derivatives suppress the infections caused by herpes simplex virus type-1 and herpes simplex virus type-2 intravaginally inoculated into mice.

We examined the in vivo antiviral activities of 2-amino-4,4α-dihydro-4α-7-dimethyl-3H-phenoxazine-3-one (Phx-1), 3-amino-1,4α-dihydro-4α-8-dimethyl-2H-phenoxazine-2-one (Phx-2), and 2-aminophenoxazine-3-one (Phx-3) against herpes viruses. The virus yield three days after administration, changes in the 6-degree's lesion scores, and the morbidity were assessed after herpes simplex virus type-1 (HSV-1) [acyclovir (ACV)-sensitive KOS strain or ACV-resistant A4-3 strain] or HSV-2 (ACV-sensitive UW 268 strain) was inoculated intravaginally to mice with administration of Phx-1, Phx-2, Phx-3, or ACV (0.2 mg per administration, 3 times daily) for 8 days starting from 1 day before virus inoculation to 7 days after infection. Phx-1, Phx-2, and Phx-3 extensively suppressed the virus yield of HSV-1. Only Phx-2 exerted moderate inhibitory effects against HSV-2 in mice. The lesion scores, as clinical signs manifested by infection of the KOS strain of HSV-1, were extensively suppressed by intravaginal application of Phx-1, Phx-2, or Phx-3. The lesion scores in HSV-2-infected mice indicated moderate suppression, when Phx-1, Phx-2, or Phx-3 was applied. Without treatment by one of the compounds, none of the HSV-1-infected mice died, but all the HSV-2-infected ones did. However, by the administration of Phx-1, Phx-2, or Phx-3 fairly improved the survival rates of the HSV-2-infected mice. Phx-2 showed dose-dependent anti-HSV-2 efficacy when administered at doses of 0.2 and 1 mg per administration. The present in vivo data suggest that the Phx-1, Phx-2, and Phx-3 are attractive candidates for agents to prevent both replication of HSV and aggravation of lesions caused by these viruses.

2-aminophenoxazine-3-one prevents pulmonary metastasis of mouse B16 melanoma cells in mice.

2-Aminophenoxazine-3-one (Phx-3) induced cellular apoptosis in mouse melanoma B16 cells as detected by DNA laddering and upregulated Fas expression in the cells in vitro. Next, the anti-metastatic effects of Phx-3 were investigated in C56BL/6 mice. When B16 melanoma cells were injected into the tail veins of mice, significant metastasis of the cells was indicated in the lungs, 14 days after treatment. In contrast, when 0.5 mg/kg Phx-3 was administered to mice through the tail veins, once simultaneously with or every three days after the administration of B16 melanoma cells, the number of metastasized pulmonary cells was extremely reduced. Moderate reduction of the number of metastasized pulmonary cells was indicated in the mice with a single dose of Phx-3 on day 3 after injection of the cells. However, when Phx-3 was administered in a single dose, 6 or 9 days after the injection of the cells, the number of metastasized pulmonary cells remained the same. The present results indicate that the metastasis of mouse B16 melanoma cells to the lung was significantly inhibited in mice administered Phx-3, which activated the intrinsic and extrinsic apoptotic pathways. The present study suggests that Phx-3 might be a potential anti-metastatic agent as well as an anticancer agent.

Anticancer activity of phenoxazines produced by bovine erythrocytes on colon cancer cells.

The present study investigated the anticancer activity of 2-aminophenoxazine-3-one (Phx-3) and 2-amino-4,4 alpha-dihydro-4 alpha,7-dimethyl-3H-phenoxazine-3-one (Phx-1), which were obtained by improved preparation methods using bovine erythrocyte suspension, on colon cancer cell lines COLO201, DLD1 and PMCO1 in vitro. The preparation methods for Phx-1 and Phx-3 had the advantages of extensively shortening reaction time and reducing sample volumes up to one-seventh during treatment, compared with the conventional method using bovine hemoglobin solution, resulting in extensive reduction of handling time. Phx-1 and Phx-3 thus obtained were identified as pure by the absorption spectra and NMR spectra. These phenoxazines exerted strong, dose-dependent anticancer activity against colon cancer cell lines COLO201, DLD1 and PMCO1 in vitro and induced apoptosis of these cells. The present results demonstrate that Phx-1 and Phx-3, which were prepared by extensively improved methods using bovine erythrocytes, may be useful as therapeutic drugs against colon cancer that is intractable to chemotherapy.

2-Aminophenoxazine-3-one induces cellular apoptosis by causing rapid intracellular acidification and generating reactive oxygen species in human lung adenocarcinoma cells.

2-Aminophenoxazine-3-one (Phx-3)-induced apoptosis was investigated. Phx-3 suppressed the viability of human lung adenocarcinoma cell line A549 and induced cellular apoptosis 6 h after treatment. Prior to these events, intracellular pH (pHi) was rapidly decreased from pH 7.65 to 7.10 within 30 min when A549 cells were treated with 7 microM Phx-3. This intracellular acidification continued for 3 h in the cells. Augmented production of reactive oxygen species (ROS) was obseved 1 h after treatment of A549 cells with 7 microM Phx-3, and cell cycle arrest at G1 was indicated 3 h after treatment. The translocation of NF-kappaB from the cytosol to the nucleus was clearly indicated 1 h after the administration of Phx-3 to A549 cells, while it was significantly suppressed when Nac, a scavenger of ROS, was added to the cells with Phx-3. The Phx-3-induced apoptosis in A549 cells was significantly suppressed when Nac was administered to the cells. These results suggest that a decrease of pHi, caused by depolarization of the mitochondria, may trigger the dysfunction of mitochondria causing ROS production; therefore, both the translocation of NF-kappaB from the cytoplasm to the nucleus and apoptosis induction were promoted in A549 cells. Microscopic examination of the cellular localization of Phx-3 in A549 cells revealed that Phx-3 was mainly localized in the cytoplasm and the mitochondria, but not in the nucleus. The present results indicate that Phx-3 might be a strong anticancer drug against lung cancer, which is intractable to chemotherapy, by causing various early events, including the decrease of pHi and ROS production, and finally inducing cellular apoptosis.

In vitro antibacterial activity of Phx-3 against Helicobacter pylori.

Phx-3, one of the phenoxazine derivatives, is reported to have inhibitory effect on Mycobacterium species and Chlamydia pneumoniae but not Escherichia coli, Salmonella Typhimurium, Pseudomonas aeruginosa, Staphylococcus aureus, Listeria monocytogenes. The bactericidal activities of Phx-3 against Helicobacter pylori strains have not been assessed. Then, we measured minimum inhibitory concentration of Phx-3 for Helicobacter strains and assessed the morphological and biochemical effects of Phx-3 on H. pylori. In present study, it has shown that H. pylori strains including clarithromycin resistant strain and Helicobacter musterae were killed effectively by the treatment with Phx-3. Furthermore, severe morphological changes such as membrane blebbing and formation of hollows in H. pylori were detected. In addition, induction of heat shock protein 60 was observed. Taken together, Phx-3 has antibacterial activity against Helicobacter pylori.

Cytoprotective effect of imatinib mesylate in non-BCR-ABL-expressing cells along with autophagosome formation.

Treatment with imatinib mesylate (IM) results in an increased viable cell number of non-BCR-ABL-expressing cell lines by inhibiting spontaneous apoptosis. Electron microscopy revealed an increase of autophagosomes in response to IM. IM attenuated the cytotoxic effect of cytosine arabinoside, as well as inhibiting cell death with serum-deprived culture. Cytoprotection with autophagosome formation by IM was observed in various leukemia and cancer cell lines as well as normal murine embryonic fibroblasts (MEFs). Complete inhibition of autophagy by knockdown of atg5 in the Tet-off atg5(-/-) MEF system attenuated the cytoprotective effect of IM, indicating that the effect is partially dependent on autophagy. However, cytoprotection by IM was not mediated through suppression of ROS production via mitophagy, ER stress via ribophagy, or proapoptotic function of ABL kinase. Although the target tyrosine kinase(s) of IM remains unclear, our data provide novel therapeutic possibilities of using IM for cytoprotection.