Risk factors for postgastric endoscopic submucosal dissection bleeding in direct oral anticoagulant users.

OBJECTIVES: Bleeding after endoscopic submucosal dissection (ESD) for gastric tumors in patients taking antithrombotic drugs, in particular direct oral anticoagulants (DOACs), remains unresolved; therefore, we evaluated the risk factors for post-ESD bleeding and drug differences in patients taking DOACs. METHODS: We included 278 patients taking antithrombotic drugs who underwent gastric ESD between January 2017 and March 2022. Antithrombotic drugs were withdrawn following the 2017 guidelines (Appendix on anticoagulants including DOACs). To further clarify differences in antithrombotic agents' effects, the peri-cancerous mucosa in the resected specimen was pathologically evaluated according to the Updated Sydney System. Multivariate analysis was performed to assess the risk of post-ESD bleeding. RESULTS: The incidence of post-ESD bleeding in patients taking DOACs was 19.6% (10/51). Among patients taking antithrombotic drugs, DOACs were identified as a possible factor involved in post-ESD bleeding (odds ratio [OR] 4.92). Among patients taking DOACs, possible factors included resection length diameter ≥30 mm (OR 3.72), presence of neutrophil infiltration (OR 2.71), lesions occurring in the lower third of stomach (OR 2.34), and preoperative antiplatelet use (OR 2.22). Post-ESD bleeding by DOAC type was 25.0% of patients (4/16) receiving apixaban, in 20.0% (3/15) receiving edoxaban, in 21.4% (3/14) receiving rivaroxaban, and in none of those receiving dabigatran. CONCLUSIONS: The administration of DOACs was shown to be a possible factor involved in post-ESD bleeding, and risk factors for patients taking DOACs included neutrophil infiltration. The pharmacological differences in the effects of DOACs contributing to bleeding in gastric ulcers suggest comparatively less bleeding with dabigatran after ESD.

Long-term monitoring of gastric mucosa-associated lymphoid tissue lymphoma in patients with extra copies of the MALT1 gene.

The objective of this study was to clarify the long-term prognosis of patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma with additional copies of MALT1. In this multicenter retrospective study, we enrolled 145 patients with gastric MALT lymphoma who underwent fluorescence in situ hybridization (FISH) analysis to detect t(11;18) translocation. The patient cohort was divided into three groups: Group A (n = 87), comprising individuals devoid of the t(11;18) translocation or extra MALT1 copies; Group B (n = 27), encompassing patients characterized by the presence of the t(11;18) translocation; and Group C (n = 31), including patients with extra MALT1 copies. The clinical outcomes in each cohort were collected. Over the course of a mean follow-up of 8.5 ± 4.2 years, one patient died of progressive MALT lymphoma, while 15 patients died due to etiologies unrelated to lymphoma. The progression or relapse of MALT lymphoma was observed in 11 patients: three in Group A, two in Group B, and six in Group C. In Groups A, B, and C, the 10-year overall survival rates were 82.5%, 93.8%, and 86.4%, respectively, and the 10-year event-free survival rates were 96.1%, 96.0%, and 82.9%, respectively. The event-free survival rate in Group C was significantly lower than that in Group A. However, no differences were observed in the 10-year event-free survival rates among individuals limited to stage I or II1 disease (equivalent to excluding patients with stage IV disease in this study, as there were no patients with stage II2), with rates of 98.6%, 95.8%, and 92.3% for Groups A, B, and C, respectively. In conclusion, the presence of extra copies of MALT1 was identified as an inferior prognostic determinant of event-free survival. Consequently, trisomy/tetrasomy 18 may serve as an indicator of progression and refractoriness to therapeutic intervention in patients with gastric MALT lymphoma, particularly stage IV gastric MALT lymphoma.

Electron Paramagnetic Resonance Implemented with Multiple Harmonic Detections Successfully Maps Extracellular pH In Vivo.

Extracellular acidification indicates a metabolic shift in cancer cells and is, along with tissue hypoxia, a hallmark of tumor malignancy. Thus, non-invasive mapping of extracellular pH (pHe) is essential for researchers to understand the tumor microenvironment and to monitor tumor response to metabolism-targeting drugs. While electron paramagnetic resonance (EPR) has been successfully used to map pHe in mouse xenograft models, this method is not sensitive enough to map pHe with a moderate amount of exogenous pH-sensitive probes. Here, we show that a modified EPR system achieves twofold higher sensitivity by using the multiple harmonic detection (MHD) method and improves the robustness of pHe mapping in mouse xenograft models. Our results demonstrate that treatment of a mouse xenograft model of human-derived pancreatic ductal adenocarcinoma cells with the carbonic anhydrase IX (CAIX) inhibitor U-104 delays tumor growth with a concurrent tendency toward further extracellular acidification. We anticipate that EPR-based pHe mapping can be expanded to monitor the response of other metabolism-targeting drugs. Furthermore, pHe monitoring can also be used for the development of improved metabolism-targeting cancer treatments.

Dasatinib-induced colitis: clinical, endoscopic and histological findings.

BACKGROUND: Dasatinib, a second-generation tyrosine kinase inhibitor, is widely used in patients with haematological malignancies. The main side effects of dasatinib are myelosuppression and pleural effusion; however, colitis, such as haemorrhagic colitis and cytomegalovirus (CMV) colitis, have been reported as rare side effects. There are only a few studies conducted on dasatinib-induced colitis. AIMS: This study aimed to clarify the clinical, endoscopic and pathological features of dasatinib-induced colitis. METHODS: This retrospective study included 51 consecutive patients who received dasatinib therapy between June 2009 and July 2020. Dasatinib-induced colitis was defined as the presence of colitis symptoms, exclusion of other diseases that could cause colitis, and improvement in symptoms after dasatinib withdrawal or dose reduction. CMV positivity was determined based on the positive result of CMV immunostaining. RESULTS: Dasatinib-induced colitis was diagnosed in nine of 51 patients (17.6%), and most of the symptoms were mild diarrhoea and bloody stools. The endoscopic findings were characterised by loss of vascular pattern (100%) and multiple small erosions (83.3%) which were mainly found in the transverse and descending colon. In a patient who underwent follow-up colonoscopy once a year while taking dasatinib, endoscopic findings changed from initial erythematous spots to multiple erosions, and finally to multiple small round elevations with erosion on the top that disappeared after discontinuation of dasatinib. Anti-CMV therapy was administered to one patient, but the treatment failed. All patients with dasatinib-induced colitis were cured after the discontinuation of dasatinib. CONCLUSION: Physicians should consider CMV reactivation to manage dasatinib-induced colitis.

Metformin preferentially enhances the radio-sensitivity of cancer stem-like cells with highly mitochondrial respiration ability in HMPOS.

Metformin has many anti-cancer effects, alone or in combination with radiation. However, the mechanism underlying its radio-sensitized effect is still unclear, especially for cancer stem-like cells (CSCs). Here, the radio-sensitized effect of metformin was investigated, and its mechanism was revealed in CSCs derived from canine osteosarcoma cell line (HMPOS), a canine osteosarcoma cell line. Spheroid cells (SCs) were used as CSCs-rich cells derived from sphere formation, and SCs were compared with normal adherent culture cells (ACs). The radio-sensitizing effect of metformin using clonogenic assay and tumor growth in mice xenograft model were evaluated, and the mechanism of its radio-sensitization focusing on mitochondrial function was revealed. Metformin significantly enhanced radio-sensitivity of SCs through its inhibition of the mitochondrial function, as shown by decreased oxygen consumption, decreased mitochondrial membrane potential, and decreased ATP production. Additionally, SCs had a higher ability of mitochondrial respiration than ACs, which may have caused difference of their sensitivity of metformin and irradiation. In conclusion, mitochondrial function might play an important role in the sensitivity of metformin and irradiation, and drugs that target mitochondrial respiration, such as metformin, are promising radio-sensitizers to target CSCs.

Radiation-induced abnormal centrosome amplification and mitotic catastrophe in human cervical tumor HeLa cells and murine mammary tumor EMT6 cells.

Mitotic catastrophe is a form of cell death linked to aberrant mitosis caused by improper or uncoordinated mitotic progression. Abnormal centrosome amplification and mitotic catastrophe occur simultaneously, and some cells with amplified centrosomes enter aberrant mitosis, but it is not clear whether abnormal centrosome amplification triggers mitotic catastrophe. Here, to investigate whether radiation-induced abnormal centrosome amplification is essential for induction of radiation-induced mitotic catastrophe, centrinone-B, a highly selective inhibitor of polo-like kinase 4, was utilized to inhibit centrosome amplification, since polo-like kinase 4 is an essential kinase in centrosome duplication. When human cervical tumor HeLa cells and murine mammary tumor EMT6 cells were irradiated with 2.5 Gy of X-rays, cells with morphological features of mitotic catastrophe and the number of cells having >2 centrosomes increased in both cell lines. Although centrinone-B significantly inhibited radiation-induced abnormal centrosome amplification in both cell lines, such treatment did not change cell growth and significantly enhanced mitotic catastrophe in HeLa cells exposed to X-rays. In contrast, inhibition of centrosome amplification reduced cell growth and mitotic catastrophe in EMT6 cells exposed to X-rays. These results indicated that the role of radiation-induced abnormal centrosome amplification in radiation-induced mitotic catastrophe changes, depending on the cell type.

Neuroendocrine carcinoma arising from Barrett's esophageal adenocarcinoma: a case report.

Neuroendocrine carcinoma in Barrett's esophagus is rare and its developmental mechanisms remain unclear. Neuroendocrine carcinoma arising in Barrett's esophagus with adenocarcinoma was detected at an early stage and resected by endoscopic submucosal dissection. Detailed pathological examination revealed that the neuroendocrine carcinoma originated via differentiation of the preexisting adenocarcinoma. A 79-year-old man presented with a flat protruding lesion in the esophagogastric junction. Esophagogastroduodenoscopy revealed a red flat 10-mm protruding lesion in the Barrett's epithelium and a shallow depression at the distal end. Narrow band imaging with magnification showed that the blood vessels in the protrusion were dilated and meandered irregularly, while those in the depression were small and did not form a network; the blood vessels were missing in some parts of the depression. Well-differentiated adenocarcinoma was diagnosed after analysis of the biopsy specimen of the protrusion, and endoscopic submucosal dissection was performed. The pathological diagnosis was neuroendocrine carcinoma with an adenocarcinoma component.

Mitochondrial fission promotes radiation-induced increase in intracellular Ca2+ level leading to mitotic catastrophe in mouse breast cancer EMT6 cells.

Mitochondrial dynamics are crucial for cellular survival in response to various stresses. Previously, we reported that Drp1 promoted mitochondrial fission after x-irradiation and its inhibition resulted in reduced cellular radiosensitivity and mitotic catastrophe. However, the mechanisms of radiation-induced mitotic catastrophe related to mitochondrial fission remain unclear. In this study, we investigated the involvement of cellular ATP production, ROS generation, and Ca2+ levels in mitotic catastrophe in EMT6 cells. Knockdown of Drp1 and Fis1, which are mitochondrial fission regulators, resulted in elongated mitochondria and significantly attenuated cellular radiosensitivity. Reduced mitochondrial fission mainly decreased mitotic catastrophe rather than necrosis and apoptosis after irradiation. Cellular ATP contents in Drp1 and Fis1 knockdown cells were similar to those in control cells. N-acetylcysteine and 2-glucopyranoside ascorbic acid have no effect on mitotic catastrophe after irradiation. The cellular [Ca2+]i level increased after irradiation, which was completely suppressed by Drp1 and Fis1 inhibition. Furthermore, BAPTA-AM significantly reduced radiation-induced mitotic catastrophe, indicating that cellular Ca2+ is a key mediator of mitotic catastrophe induction after irradiation. These results suggest that mitochondrial fission is associated with radiation-induced mitotic catastrophe via cytosolic Ca2+ regulation.

Inhibition of ubiquitin-specific protease 2 causes accumulation of reactive oxygen species, mitochondria dysfunction, and intracellular ATP decrement in C2C12 myoblasts.

Ubiquitin-specific protease 2 (USP2) is considered to participate in the differentiation of myoblasts to myotubes, however, its functions in myoblasts under growth conditions remain elusive. In this study, we analyzed the physiological roles of USP2 in myoblasts using Usp2 knockout (KO) C2C12 cells as well as a USP2 specific inhibitor. In addition to the disruption of differentiation, clustered regularly interspaced short palindromic repeats/Cas9-generated Usp2KO cells exhibited inhibition of proliferation compared to parental C2C12 cells. Usp2KO cells reduced the accumulation of intracellular adenosine triphosphate (ATP) content and oxygen consumption. Moreover, Usp2KO cells had fragmented mitochondria, suggesting that mitochondrial respiration was inactive. The deficiency of Usp2 did not affect the enzymatic activities of respiratory chain complexes I, III, IV, and V. However, mitochondrial membrane permeability-evaluated using calcein AM-cobalt staining-was increased in Usp2KO cells. The membrane potential of Usp2KO cells was clearly decreased. Usp2KO cells accumulated reactive oxygen species (ROS) in the mitochondria. The USP2-selective inhibitor ML364 also increased the levels of mitochondrial ROS, and modulated the membrane potential and morphology of the mitochondria. These effects were followed by a decrement in the intracellular content of ATP. Based on these findings, we speculate that USP2 may be involved in maintaining the integrity of the mitochondrial membrane. This process ensures the supply of ATP in myoblasts, presumably leading to proliferation and differentiation.

In Vivo Extracellular pH Mapping of Tumors Using Electron Paramagnetic Resonance.

An electron paramagnetic resonance (EPR)-based method for noninvasive three-dimensional extracellular pH mapping was developed using a pH-sensitive nitroxyl radical as an exogenous paramagnetic probe. Fast projection scanning with a constant magnetic field sweep enabled the acquisition of four-dimensional (3D spatial +1D spectral) EPR images within 7.5 min. Three-dimensional maps of pH were reconstructed by processing the pH-dependent spectral information on the images. To demonstrate the proposed method of pH mapping, the progress of extracellular acidosis in tumor-bearing mouse legs was studied. Furthermore, extracellular pH mapping was used to visualize the spatial distribution of acidification in different tumor xenograft mouse models of human-derived pancreatic ductal adenocarcinoma cells. The proposed EPR-based pH mapping method enabled quantitative visualization of regional changes in extracellular pH associated with altered tumor metabolism.

Evaluation of mitochondrial redox status and energy metabolism of X-irradiated HeLa cells by LC/UV, LC/MS/MS and ESR.

To evaluate the metabolic responses in tumour cells exposed to ionizing radiation, oxygen consumption rate (OCR), cellular lipid peroxidation, cellular energy status (intracellular nucleotide pool and ATP production), and mitochondrial reactive oxygen species (ROS), semiquinone (SQ), and iron-sulphur (Fe-S) cluster levels were evaluated in human cervical carcinoma HeLa cells at 12 and 24 h after X-irradiation. LC/MS/MS analysis showed that levels of 8-iso PGF2α and 5-iPF2α-VI, lipid peroxidation products of membrane arachidonic acids, were not altered significantly in X-irradiated cells, although mitochondrial ROS levels and OCR significantly increased in the cells at 24 h after irradiation. LC/UV analysis revealed that intracellular AMP, ADP, and ATP levels increased significantly after X-irradiation, but adenylate energy charge (adenylate energy charge (AEC) = [ATP + 0.5 × ADP]/[ATP + ADP + AMP]) remained unchanged after X-irradiation. In low-temperature electron spin resonance (ESR) spectra of HeLa cells, the presence of mitochondrial SQ at g = 2.004 and Fe-S cluster at g = 1.941 was observed and X-irradiation enhanced the signal intensity of SQ but not of the Fe-S cluster. Furthermore, this radiation-induced increase in SQ signal intensity disappeared on treatment with rotenone, which inhibits electron transfer from Fe-S cluster to SQ in complex I. From these results, it was suggested that an increase in OCR and imbalance in SQ and Fe-S cluster levels, which play a critical role in the mitochondrial electron transport chain (ETC), occur after X-irradiation, resulting in an increase in ATP production and ROS leakage from the activated mitochondrial ETC.

Bleeding in patients who underwent scheduled second-look endoscopy 5 days after endoscopic submucosal dissection for gastric lesions.

BACKGROUND: Bleeding after endoscopic submucosal dissection (ESD) in antithrombotic drug users is still one of the important issues to be solved. We performed scheduled second-look endoscopy (SLE) 5 days after ESD, when the resumption of antithrombotic agents is assumed to have achieved a steady state, rather than on the day after ESD. We investigated bleeding incidence and the status of ulcers. METHODS: A total of 299 lesions in 299 patients subjected to ESD for gastric neoplasms were enrolled. A double dose of proton pump inhibitors was administered after ESD. SLE was planned 5 days after ESD. Post-ESD bleeding occurring before SLE was defined as early phase post-ESD bleeding, whereas bleeding after SLE was defined as later phase post-ESD bleeding. Forrest IIa and IIb ulcers are defined as high-risk ulcers requiring prophylactic hemostasis. We investigated risk factors for post-ESD bleeding, particularly focusing on the use of antithrombotic agents and the presence of high-risk ulcers requiring prophylactic hemostasis during SLE. RESULTS: Under a double dose of proton pump inhibitors, early phase post-ESD bleeding occurred in 2.3% of non-users (5/218) and 6.2% of users of antithrombotic agents (5/81). High-risk ulcers were found in 19.0% of the cases during scheduled SLE (55/289). Later phase bleeding occurred in 5.5% of cases [2.8% of non-users (6/213) and 13.2% of users of antithrombotic agents (10/76)]. Cox regression analysis revealed that the risk factor for post-ESD bleeding was antithrombotic treatment (HR: 3.56; 95% CI: 1.63-8.02, p = 0.002) alone. Among patients with high-risk ulcers, a statistically significant increase in bleeding was observed in the later phase in patients under antithrombotic therapy, compared to those not receiving any antithrombotic agents (p = 0.001). CONCLUSIONS: Antithrombotic treatment is a risk factor for post-ESD bleeding despite SLE being scheduled 5 days after ESD. Later phase post-ESD bleeding was observed in 13.2% of the patients under antithrombotic treatment even after prophylactic hemostasis for high-risk ulcers. TRIAL REGISTRATION: This study was registered in the UMIN Clinical Trials Registry System ( 000023306 ). Retrospectively registered on 23rd July 2016.

Clinicopathological examination of ESD as salvage therapy for esophageal cancer after definitive chemo-radiation therapy.

BACKGROUND AND STUDY AIMS: Salvage therapy for esophageal cancer following chemo-radiation therapy (CRT) has not been established. We aimed to evaluate endoscopic submucosal dissection (ESD) as a salvage therapy based on histopathological features of lesions. PATIENTS AND METHODS: We compared 10 lesions in eight patients with local residual, recurrent, or metachronous esophageal squamous cell carcinoma treated by ESD after CRT (CRT group) and 59 lesions treated by ESD without CRT (non-CRT group) during the same period. RESULTS: The en bloc resection rate was 100 % while the complete resection rate was 80.0 % in the lesions after CRT, indicating no difference between the CRT and non-CRT groups. Pathological examination showed that fibrosis was more intense in the lamina propria mucosa, muscularis mucosa, and submucosa. The muscularis mucosa was thicker in both non-tumor and tumor sites in the CRT group compared to the non-CRT group. However, severe submucosal fibrosis was observed only in one lesion in the CRT group. The maximum diameter of the submucosal artery was significantly larger in the CRT group ( P  < 0.001). CONCLUSIONS: Compared to the non-CRT group, the lesions in the CRT group were accompanied by fibrosis while the muscularis mucosa were thicker; however, severe fibrosis of the submucosa was rare. It is important to dissect the muscularis mucosa appropriately during ESD, which makes successful dissection of the submucosa possible. Attention should be paid to bleeding from large arteries.

NADPH oxidase 4 mediates ROS production in radiation-induced senescent cells and promotes migration of inflammatory cells.

Excessive DNA damage induced by ionising radiation (IR) to normal tissue cells is known to trigger cellular senescence, a process termed stress-induced premature senescence (SIPS). SIPS is often accompanied by the production of reactive oxygen species (ROS), and this is reported to be important for the initiation and maintenance of SIPS. However, the source of ROS during SIPS after IR and their significance in radiation-induced normal tissue damage remain elusive. In the present study, we tested the hypothesis that the NADPH oxidase (NOX) family of proteins mediates ROS production in SIPS-induced cells after IR and plays a role in SIPS-associated biological events. X-irradiation of primary mouse embryonic fibroblasts (MEFs) resulted in cellular senescence and the concomitant increase of intracellular ROS. Among all six murine NOX isoforms (NOX1-4 and DUOX1/2), only NOX4 was detectable under basal conditions and was upregulated following IR. In addition, radiation-induced ROS production was diminished by genetic or pharmacological inhibition of NOX4. Meanwhile, NOX4 deficiency did not affect the induction of cellular senescence after IR. Furthermore, the migration of human monocytic U937 cells to the culture medium collected from irradiated MEFs was significantly reduced by NOX4 inhibition, suggesting that NOX4 promotes the recruitment of inflammatory cells. Collectively, our findings imply that NOX4 mediates ROS production in radiation-induced senescent cells and contributes to normal tissue damage after IR via the recruitment of inflammatory cells and the exacerbation of tissue inflammation.

Calmodulin-dependent protein kinase II (CaMKII) mediates radiation-induced mitochondrial fission by regulating the phosphorylation of dynamin-related protein 1 (Drp1) at serine 616.

Mitochondrial dynamics are suggested to be indispensable for the maintenance of cellular quality and function in response to various stresses. While ionizing radiation (IR) stimulates mitochondrial fission, which is mediated by the mitochondrial fission protein, dynamin-related protein 1 (Drp1), it remains unclear how IR promotes Drp1 activation and subsequent mitochondrial fission. Therefore, we conducted this study to investigate these concerns. First, we found that X-irradiation triggered Drp1 phosphorylation at serine 616 (S616) but not at serine 637 (S637). Reconstitution analysis revealed that introduction of wild-type (WT) Drp1 recovered radiation-induced mitochondrial fission, which was absent in Drp1-deficient cells. Compared with cells transfected with WT or S637A Drp1, the change in mitochondrial shape following irradiation was mitigated in S616A Drp1-transfected cells. Furthermore, inhibition of CaMKII significantly suppressed Drp1 S616 phosphorylation and mitochondrial fission induced by IR. These results suggest that Drp1 phosphorylation at S616, but not at S637, is prerequisite for radiation-induced mitochondrial fission and that CaMKII regulates Drp1 phosphorylation at S616 following irradiation.

A 750-MHz Electronically Tunable Resonator Using Microstrip Line Couplers for Electron Paramagnetic Resonance Imaging of a Mouse Tumor-Bearing Leg.

OBJECTIVE: The purpose of this work was to develop an electronically tunable resonator operating at 750 MHz for continuous-wave electron paramagnetic resonance (CW-EPR) imaging of a mouse tumor-bearing leg. METHODS: The resonator had a multi-coil parallel-gap structure with a sample space of 16 mm in diameter and 20 mm in length. Microstrip line couplers were used in conjunction with varactor diodes to enable resonance frequency adjustment and to reduce the nonlinear effects of the varactor diodes. The resonator was modeled by the finite-element method and a microwave circuit simulation was performed to clarify its radiofrequency characteristics. RESULTS: A tunable resonator was evaluated in terms of its resonance frequency, tunable frequency band, and conversion efficiency of the RF magnetic field. The developed resonator provided a tunable frequency band of 4 MHz at a central frequency of 747 MHz and a conversion efficiency of 34 µT/W1/2. To demonstrate the application of this tunable resonator to EPR imaging, three-dimensional EPR images of a sample solution and a mouse tumor-bearing leg were obtained. CONCLUSION: The developed tunable resonator satisfied our initial requirements for in vivo EPR imaging and may be able to be further improved using the present finite-element and circuit models if any problems arise during future practical applications. SIGNIFICANCE: This work may help to promote EPR imaging of tumor-bearing mice in cancer-related studies.

Lipophilic triphenylphosphonium derivatives enhance radiation-induced cell killing via inhibition of mitochondrial energy metabolism in tumor cells.

It has recently been reported that radiation enhances mitochondrial energy metabolism in various tumor cell lines. To examine how this radiation-induced alteration in mitochondrial function influences tumor cell viability, various lipophilic triphenylphosphonium (TPP+) cation derivatives and related compounds such as 4-hydroxy-2,2,6,6-tetramethyl-1-oxy-piperidin (Tempol) with TPP+ (named "Mito-") were designed to inhibit the mitochondrial electron transport chain. Mito-(CH2)10-Tempol (M10T) and its derivatives, Mito-(CH2)5-Tempol (M5T), Mito-(CH2)10-Tempol-Methyl (M10T-Me), Mito-C10H21 (M10), and C10H21-Tempol (10T), were prepared. In HeLa human cervical adenocarcinoma cells and A549 human lung carcinoma cells, the fractional uptake of the compound into mitochondria was highest among the TTP+ analogs conjugated with Tempol (M10T, M5T, and 10T). M10T, M10T-Me, and M10 exhibited strong cytotoxicity and enhanced X-irradiation-induced reproductive cell death, while 10T and M5T did not. Furthermore, M10T, M10T-Me, and M10 decreased basal mitochondrial membrane potential and intracellular ATP. M10T treatment inhibited X-ray-induced increases in ATP production. These results indicate that the TPP cation and a long hydrocarbon linker are essential for radiosensitization of tumor cells. The reduction in intracellular ATP by lipophilic TPP+ is partly responsible for the observed radiosensitization.

Gene cloning, recombinant expression, purification and characterization of l-methionine decarboxylase from Streptomyces sp. 590.

l-Methionine decarboxylase (MetDC) from Streptomyces sp. 590 depends on pyridoxal 5'-phosphate and catalyzes the non-oxidative decarboxylation of l-methionine to produce 3-methylthiopropylamine and carbon dioxide. MetDC gene (mdc) was determined to consist of 1,674 bp encoding 557 amino acids, and the amino acid sequence is similar to that of l-histidine decarboxylases and l-valine decarboxylases from Streptomyces sp. strains. The mdc gene was cloned and recombinant MetDC was heterologously expressed by Escherichia coli. The purification of recombinant MetDC was carried out by DEAE-Toyopearl and Ni-NTA agarose column chromatography. The recombinant enzyme was homodimeric with a molecular mass of 61,000 Da and showed optimal activity between 45 to 55 °C and at pH 6.6, and the stability below 30 °C and between pH 4.6 to 7.0. l-Methionine and l-norleucine were good substrates for MetDC. The Michaelis constants for l-methionine and l-norleucine were 30 and 73 mM, respectively. The recombinant MetDC (0.50 U/ml) severely inhibited growth of human tumour cells A431 (epidermoid ovarian carcinoma cell line) and MDA-MB-231 (breast cancer cell line), however showed relatively low cytotoxicity for human normal cell NHDF-Neo (dermal fibroblast cell line from neonatal foreskin). This study revealed the properties of the gene and the protein sequence of MetDC for the first time.

Uncovering Direct Targets of MiR-19a Involved in Lung Cancer Progression.

Micro RNAs (miRNAs) regulate the expression of target genes posttranscriptionally by pairing incompletely with mRNA in a sequence-specific manner. About 30% of human genes are regulated by miRNAs, and a single miRNA is capable of reducing the production of hundreds of proteins by means of incomplete pairing upon miRNA-mRNA binding. Lately, evidence implicating miRNAs in the development of lung cancers has been emerging. In particular, miR-19a, which is highly expressed in malignant lung cancer cells, is considered the key miRNA for tumorigenesis. However, its direct targets remain underreported. In the present study, we focused on six potential miR-19a target genes selected by miRNA target prediction software. To evaluate these genes as direct miR-19a target genes, we performed luciferase, pull-down, and western blot assays. The luciferase activity of plasmids with each miR-19a-binding site was observed to decrease, while increased luciferase activity was observed in the presence of anti-miR-19a locked nucleic acid (LNA). The pull-down assay showed biotinylated miR-19a to bind to AGO2 protein and to four of six potential target mRNAs. Western blot analysis showed that the expression levels of the four genes changed depending on treatment with miR-19a mimic or anti-miR-19a-LNA. Finally, FOXP1, TP53INP1, TNFAIP3, and TUSC2 were identified as miR-19a targets. To examine the function of these four target genes in lung cancer cells, LK79 (which has high miR-19a expression) and A549 (which has low miR-19a expression) were used. The expression of the four target proteins was higher in A549 than in LK79 cells. The four miR-19a target cDNA expression vectors suppressed cell viability, colony formation, migration, and invasion of A549 and LK79 cells, but LK79 cells transfected with FOXP1 and TP53INP1 cDNAs showed no difference compared to the control cells in the invasion assay.

[Clinical course of recovery from cognitive dysfunction in a patient with anti-N-methyl-D-aspartate receptor encephalitis].

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is an autoimmune disorder, which occurs commonly in young women and is often associated with ovarian teratomas. We report the case of a patient with this disease, who exhibited cognitive deficits, and describe the clinical course of recovery from cognitive dysfunction. A 29-year-old right-handed woman suffered from chills and fever for 7 days prior to admission to hospital, and complained that she could not understand the content of TV programs. Following admission to hospital, she was found to have an ovarian teratoma and underwent oophorectomy. She was diagnosed with anti-NMDA receptor encephalitis based on the presence of antibodies in the serum and cerebrospinal fluid. She subsequently experienced phases with disturbance of consciousness and involuntary movement, and then moved into the gradual recovery phase 3 months after onset. Cerebral SPECT revealed a left-dominant decrease of blood flow in the prefrontal regions bilaterally. Neuropsychological examination 3 months after onset revealed frontal lobe syndrome comprising executive dysfunction, decreased spontaneity, and environmental dependency in addition to recent memory deficits. Approximately 6 months after onset, recent memory impairments and environmental dependency were resolved, and a gradual improvement in spontaneity and executive function was seen. One year after onset, the patient had regained independence and ability to self-care, and returned to her workplace. Our observations suggest that patients with anti-NMDA receptor encephalitis may recover from frontal lobe syndrome, including executive dysfunction and decreased spontaneity, slower than patients with other cognitive dysfunctions do.