Oncogenic signaling by Kit tyrosine kinase occurs selectively on the Golgi apparatus in gastrointestinal stromal tumors.

Gastrointestinal stromal tumors (GISTs) are caused by gain-of-function mutations in the Kit receptor tyrosine kinase. Most primary GIST patients respond to the Kit inhibitor imatinib, but this drug often becomes ineffective because of secondary mutations in the Kit kinase domain. The characteristic intracellular accumulation of imatinib-sensitive and -resistant Kit protein is well documented, but its relationship to oncogenic signaling remains unknown. Here, we show that in cancer tissue from primary GIST patients as well as in cell lines, mutant Kit accumulates on the Golgi apparatus, whereas normal Kit localizes to the plasma membrane (PM). In imatinib-resistant GIST with a secondary Kit mutation, Kit localizes predominantly on the Golgi apparatus. Both imatinib-sensitive and imatinib-resistant Kit (Kit(mut)) become fully auto-phosphorylated only on the Golgi and only if in a complex-glycosylated form. Kit(mut) accumulates on the Golgi during the early secretory pathway, but not after endocytosis. The aberrant kinase activity of Kit(mut) prevents its export from the Golgi to the PM. Furthermore, Kit(mut) on the Golgi signals and activates the phosphatidylinositol 3-kinase-Akt (PI3K-Akt) pathway, signal transducer and activator of transcription 5 (STAT5), and the Mek-Erk pathway. Blocking the biosynthetic transport of Kit(mut) to the Golgi from the endoplasmic reticulum inhibits oncogenic signaling. PM localization of Kit(mut) is not required for its signaling. Activation of Src-family tyrosine kinases on the Golgi is essential for oncogenic Kit signaling. These results suggest that the Golgi apparatus serves as a platform for oncogenic Kit signaling. Our study demonstrates that Kit(mut)'s pathogenicity is related to its mis-localization, and may offer a new strategy for treating imatinib-resistant GISTs.

Calibration of the microcalorimeter spectrometer on-board the Hitomi (Astro-H) observatory (invited).

The Hitomi Soft X-ray Spectrometer (SXS) was a pioneering non-dispersive imaging x-ray spectrometer with 5 eV FWHM energy resolution, consisting of an array of 36 silicon-thermistor microcalorimeters at the focus of a high-throughput soft x-ray telescope. The instrument enabled astrophysical plasma diagnostics in the 0.3-12 keV band. We introduce the SXS calibration strategy and corresponding ground calibration measurements that took place from 2012-2015, including both the characterization of the microcalorimeter array and measurements of the x-ray transmission of optical blocking filters.

Effects of bisphosphonates on human esophageal squamous cell carcinoma cell survival.

Esophageal squamous cell carcinoma (ESCC) is one of the most malignant cancers in Japan. Anticancer chemotherapy has been useful for ESCC treatment. However, therapeutic options are limited. Recently, bisphosphonates (BPs), which are osteoporosis drugs, have shown anticancer effects in several cancer cell lines, but the effects against ESCC cell lines are unknown. In this study, we examined the cytotoxic effects of BPs and their mechanisms of cytotoxicity in human ESCC cell lines. A first-generation BP (etidronate), two second-generation BPs (alendronate and pamidronate), and two third-generation BPs (risedronate and zoledronate) were used in this study. All BPs, except etidronate, were cytotoxic, as indicated by increased caspase-3/7 activity and numbers of Annexin-fluorescein isothiocyanate positive cells in ESCC cell lines. From cell cycle analysis, G0/G1-phase arrest was observed upon treatment with second- and third-generation BPs. In addition, Cyclin D1 protein expression levels were decreased by second- and third-generation BP treatment. Although squalene and trans, trans-farnesol minimally affected BP cytotoxicity, treatment with geranylgeraniol inhibited BP cytotoxicity almost completely. We concluded that second- and third-generation BPs are cytotoxic to ESCC cell lines as they induce apoptosis and inhibit the cell cycle through mevalonate pathway inhibition. Therefore, BP treatment may be a beneficial therapy in ESCC patients.

Tunable terahertz emission from the intrinsic Josephson junctions in acute isosceles triangular Bi2Sr2CaCu2O8+δ mesas.

In order to determine if the mesa geometry might affect the properties of the coherent terahertz (THz) radiation emitted from the intrinsic Josephson junctions in mesas constructed from single crystals of the high-temperature superconductor, Bi2Sr2CaCu2O8+δ, we studied triangular mesas. For equilateral triangular mesas, the observed emission was found to be limited to the single mesa TM(1,0) mode. However, tunable radiation over the range from 0.495 to 0.934 THz was found to arise from an acute isosceles triangular mesa. This 47% tunability is the widest yet observed from the outer current-voltage characteristic branch of such mesas of any geometry. Although the radiation at a few of the frequencies in the tunable range appear to have been enhanced by cavity resonances, most frequencies are far from such resonance frequencies, and can only be attributed to the ac-Josephson effect.

MicroRNA-mediated upregulation of integrin-linked kinase promotes Src-induced tumor progression.

The tyrosine kinase c-Src is upregulated in various human cancers; however, the molecular mechanisms underlying c-Src-mediated tumor progression remain unclear. Here we show that downregulation of microRNA (miR)-542-3p is tightly associated with tumor progression via c-Src-related oncogenic pathways. In c-Src-transformed fibroblasts and human cancer cells that overexpress c-Src, miR-542-3p is substantially downregulated, and the ectopic expression of miR-542-3p suppresses tumor growth. We identified the integrin-linked kinase (ILK) as a conserved target of miR-542-3p. ILK upregulation promotes cell adhesion and invasion by activating the integrin-focal adhesion kinase (FAK)/c-Src pathway, and can also contribute to tumor growth via the AKT and glycogen synthase kinase 3ß pathways. MiR-542-3p expression is downregulated by the activation of c-Src-related signaling molecules, including epidermal growth factor receptor, K-Ras and Ras/Raf/mitogen-activated protein kinase/extracellular signal-regulated kinase. In human colon cancer tissues, downregulation of miR-542-3p is significantly correlated with the upregulation of c-Src and ILK. Our results suggest that the novel c-Src-miR-542-3p-ILK-FAK circuit plays a crucial role in controlling tumor progression.

Prolonged carotid sinus reflex is a risk factor for contrast-induced nephropathy following carotid artery stenting.

BACKGROUND AND PURPOSE: Although many studies have demonstrated that CIN is associated with in-hospital and long-term mortality, the incidence of CIN following CAS is unclear. We investigated the incidence of CIN, defined as an increase from a baseline creatinine value of at least 0.5 mg/dL or 25% within 72 hours of contrast administration, and we also examined renal function in the late phase after CAS. MATERIALS AND METHODS: We examined 80 patients who underwent CAS between April 2005 and December 2009. Clinical background, laboratory data, contrast volume, and clinical course were collected and analyzed. RESULTS: The incidence of CIN was 8.8% (7/80), and no patients required hemodialysis. In the group that developed CIN, prolonged CSR after CAS was found in 57.1% (4/7) of cases; this incidence differed significantly (P = .001) from that in the group without development of CIN. Neither preoperative renal function, contrast volume, nor history was related to the incidence of CIN, while on multivariate analysis, prolonged CSR was found to be an independent risk factor for CIN. The incidence of elevation in creatinine values at 6 months after CAS was 8.2% (6/73). All patients who developed delayed renal impairment had pre-existing CKD; this finding differed significantly (P = .04) from that in the group without development of delayed renal impairment. CONCLUSIONS: Because patients who develop prolonged CSR after CAS are at increased risk of perioperative major adverse clinical events including CIN, patients at high risk for this condition should be carefully managed to prevent increased morbidity and mortality.

A case of Helicobacter pylori infection complicated with gastric cancer, gastric mucosa-associated lymphoid tissue lymphoma, and idiopathic thrombocytopenic purpura successfully treated with laparoscopy-assisted total gastrectomy and splenectomy.

Helicobacter pylori infection plays a key role in the pathogenesis of H. pylori-associated diseases, including gastroduodenal and non-gastroduodenal diseases. A 71-year-old man was evaluated for a positive fecal occult blood test by upper gastrointestinal endoscopy, which revealed H. pylori infection, two adenocarcinomas and two gastric mucosa-associated lymphoid tissue lymphomas. Hematological examination revealed low platelet-count, elevated platelet-associated immunoglobulin G and anti-H. pylori immunoglobulin G antibodies. We diagnosed H. pylori infection complicated by simultaneous occurrence of gastric cancer, gastric mucosa-associated lymphoid tissue lymphoma, and idiopathic thrombocytopenic purpura. These diseases were successfully treated with laparoscopy-assisted total gastrectomy and splenectomy, and there was no evidence of recurrence for about 2 years. This is the first reported case of H. pylori infection complicated by these three diseases and cured with laparoscopic surgery.

Pharmacokinetic modeling of the dosing interval dependency for the interaction between itraconazole and triazolam.

OBJECTIVE: Itraconazole is a potent inhibitor of cytochrome P450 (CYP) 3A with an elimination half-life of more than 30 hours. Therefore, itraconazole may cause persistent CYP3A inhibition. Triazolam is primarily metabolized by CYP3A and its plasma concentration is increased remarkably by itraconazole. Although separating their dosages by 24 hours has been shown to reduce the interaction, an appropriate dosage interval remains to be determined. The aim of this study was to identify an appropriate dosage schedule to avoid their interaction. MATERIALS AND METHODS: We developed a pharmacokinetic model based on the assumption that both itraconazole and hydroxyitraconazole competitively and reversibly inhibit the first-pass metabolism and systemic elimination of triazolam. The developed model was simultaneously fitted to the plasma concentration profiles of triazolam, taken from the literature, by using the plasma concentration-time profiles of itraconazole and hydroxyitraconazole as input functions to estimate their in vivo Ki values. Subsequently, we simulated the plasma concentration profiles of triazolam administered after itraconazole therapy with various dosing intervals. RESULTS: The model could explain and simulate the interaction between itraconazole-triazolam using a variety of dosage intervals between the administrations. CONCLUSIONS: The developed model may provide useful information with regard to the appropriate interval for triazolam administration during itraconazole therapy.

The effect of recombinant aminopeptidase A on hypertension in spontaneously hypertensive rats: its effect in comparison with candesartan.

An understanding of aminopeptidase A in hypertension is important, given its ability to cleave the N-terminal aspartic acid of potent vasoconstrictor angiotensin II. However, the role of aminopeptidase A in hypertension has received limited attention. Because we have succeeded in producing recombinant human aminopeptidase A, the effect of aminopeptidase A on systolic blood pressure in the spontaneously hypertensive rat was examined. Aminopeptidase A of 0.016 mg/kg was administrated intravenously to spontaneously hypertensive rats and blood pressure was monitored for 72 h. For repeated administration, aminopeptidase A doses of 0.016 mg/kg and 0.1-mg/kg doses of candesartan (an angiotensin II receptor 1 subtype blocker) were administrated daily in spontaneously hypertensive rats and blood pressure was monitored for 5 d. Bolus intravenous injection of aminopeptidase A at a dose of 0.016 mg/kg significantly decreased systolic blood pressure for 36 h in spontaneously hypertensive rats. A comparison of the antihypertensive effects of aminopeptidase A versus candesartan in spontaneously hypertensive rats showed that the effective dose of aminopeptidase A was about one-tenth that of candesartan. These results suggest the novel approach of utilizing aminopeptidase A to treat hypertension by degrading circulating angiotensin II before it binds to the receptor 1 subtype.

A clinicopathologic study of p27(kip1) expression in renal allograft biopsy.

BACKGROUND: P27 (Kip1) is an inhibitor of cyclin-dependent kinases/cyclin complex that keeps mature cells growth-arrested. In IgA nephropathy, a decreased p27kip1 expression in podocytes has been reported to be related to lesion formation of focal segmental glomerulosclerosis and renal dysfunction. We reviewed the p27kip1 expression in transplanted kidneys. METHODS: p27kip1 expression was examined immunohistochemically in 26 allograft biopsy specimens. RESULTS: p27kip1 expression was recognized in podocytes. Patients with more than 0.5 g proteinuria showed fewer p27kip1-positive cells than those with less than 0.5 g proteinuria. The decreased p27kip1 expression in podocytes was related to cg and ah of the Banff 97 classification. In the two cases in which p27kip1 expression was remarkably decreased, elevation of the serum creatinine level was recognized at the time of biopsy, resulting in kidney transplant loss. The histological findings were chronic/sclerosing allograft nephropathy grade II-(b) in both cases. CONCLUSION: In conclusion, decreased p27kip1 expression in podocytes suggested a significant role in proteinuria among renal transplant recipients.

Antacid interaction with new quinolones: dose regimen recommendations based on pharmacokinetic modeling of clinical data for ciprofloxacin, gatifloxacin and norfloxacin and metal cations.

OBJECTIVE: New quinolones (NQs) are widely used to treat various infections. However, concomitant oral administration of metal cations may decrease absorption of NQs and consequently decrease their blood concentration and pharmacological effect. A convenient approach to avoid this interaction is to separate the dosages by a certain interval. In this study, we aimed to develop a novel pharmacokinetic model to describe NQs-metal cation interactions in order to estimate the optimal dosing interval. METHODS: Plasma concentration-time profiles of NQs after administration without or with metal cations at various dosing intervals were collected from the literature and analyzed with a pharmacokinetic model incorporating the formation ofNQs-metal cations complex. The model was fitted to the reported time profiles ofciprofloxacin (CPFX) plasma concentration after concomitant administration with aluminum hydroxide/magnesium hydroxide antacid (Al/Mg antacid; Maalox, Maalox70) at various dosing intervals to obtain the pharmacokinetic parameters of CPFX. Model analysis was also carried out for gatifloxacin (GFLX) and norfloxacin (NFLX). RESULTS: The developed model could adequately explain the interactions in all the combinations investigated. The model predicted, in the cases of usual doses of CPFX with Maalox, GFLX with Maalox70 and NFLX with sucralfate, that the NQ should be administered 4.5, 4.5 and 3.5 hours after, or 1, 1 and 0.5 hours before the administration of metal cations, respectively, to ensure 90% of control absorption. CONCLUSIONS: The developed model can adequately describe the extent of interaction between NQs and metal cations, and should be clinically useful to design dosage regimens to circumvent the interaction.

Dosage adjustment of quinolone antibiotics and angiotensin-converting enzyme inhibitors in patients with renal dysfunction.

The aim of this study was to verify an approach for calculating pharmacokinetic parameters suitable for adjusting dosage regimens in patients with renal dysfunction. We carried out a retrospective analysis of the pharmacokinetic profiles of 12 new quinolone antibiotics and 11 angiotensin-converting enzyme inhibitors (ACEIs) in patients with normal and impaired renal function to obtain the renal excretion ratio (R(renal)) of each drug. We demonstrated that the pharmacokinetics of each drug in a patient with renal dysfunction can be adequately estimated using the R(renaI) value of each drug together with the creatinine clearance as an index of the individual's renal function. Using the R(renaI) value obtained, we could successfully simulate pharmacokinetic profiles of the drugs in publications other than that used to obtain the R(renal) values. On the other hand, age-related changes in the pharmacokinetics of new quinolone antibiotics are not always adequately predicted using the R(renal) value compared to using creatinine clearance alone as an index, and the reasons for this are not fully understood. These results demonstrate that dosage regimens of quinolone antibiotics and ACEIs in patients with renal dysfunction can be adequately optimized using the R(renal) value for each drug using the present approach.

Importance of lymph vessels in gastric cancer: a prognostic indicator in general and a predictor for lymph node metastasis in early stage cancer.

BACKGROUND: Metastasis to regional lymph nodes (LNs) through lymphatic vessels is common in cancer progression and is an important prognostic factor in many cancers. Recent evidence suggests that tumour lymphangiogenesis promotes lymphatic metastasis. AIMS: To study the role of lymph vessel density (LVD) in gastric cancer and investigate whether LVD is associated with LN metastasis/prognosis. METHODS: Lymphatics of 117 primary human gastric cancer cases were investigated by quantitative immunohistochemical staining for podoplanin. The relation between LVD and LN metastasis and other established clinicopathological parameters was analysed. The relation between LVD and prognosis was also studied. RESULTS: Mean LVD of "hot spots" was 11.6/case. LVD significantly correlated with LN and podoplanin positive lymphatic invasion. High LVD was associated with worse overall survival. In multivariate analysis, positive LVD was a significant independent predictor of overall survival, depth of invasion, and TNM stage. LVD significantly correlated with LN metastasis at surgery and podoplanin positive lymphatic invasion. In multivariate analysis, positive LVD was an independent significant predictor of LN metastasis. CONCLUSIONS: Increased podoplanin expression is significantly associated with LN metastasis, and may play an important role in detecting LN metastasis in gastric cancer. Furthermore, LVD may be a significant prognostic factor in gastric cancer at any stage. In addition, LVD and lymph vessel invasion detected by podoplanin immunohistochemistry are associated with LN metastasis in T1 early gastric cancer. LVD assessment by podoplanin immunohistochemistry may become a useful predictor of LN metastasis in T1 early gastric cancer and may influence the decision making process for additional surgery.

Helicobacter bilis infection in biliary tract cancer.

BACKGROUND: Biliary tract cancer is a highly fatal disease with poor prognosis, but the aetiology is poorly understood. AIM: We aimed to identify Helicobacter bilis infection in the gallbladder in patients with biliary tract disease. METHODS: Archival gallbladder specimens from 34 patients (14 males and 20 females) with an average age of 61.4 +/- 12.2 years (mean +/- SE) were retrieved, consisting of 11 cases of gallbladder cancer, three of bile duct cancer, 16 of cholecystolithiasis and four of pancreatic cancer. DNA was extracted and nested PCR using primers specific for 16S rRNA of H. bilis was performed. RESULTS: Amplification was observed in 3 of 11 gallbladder cancer cases (27.2%) and one of three cases with biliary duct cancer (33.3%). In total, four of 14 cases with biliary tract cancer were positive for H. bilis (28.6%). In addition, the presence of H. bilis was shown in two of 16 cases (12.5%) with cholecystolithiasis. Notably, although the number of cases examined was small, none of the four cases with pancreatic cancer showed the presence of H. bilis infection in the gallbladder without apparent abnormalities. CONCLUSION: H. bilis infection may play a role in biliary tract disease, particularly in biliary tract cancer.

Possible involvement of placental peptidases that degrade gonadotropin-releasing hormone (GnRH) in the dynamic pattern of placental hCG secretion via GnRH degradation.

The presence of an extrahypothalamic gonadotropin releasing hormone (GnRH) in human placenta is well known and this decapeptide is presumed to play an important role in the regulation of the function and growth of human placenta. Immunohistochemistry showed that neutral endopeptidase 24.11 (NEP), a candidate of the responsible enzyme of GnRH degradation, is highly expressed on the cell surface of trophoblasts. Hydrolysis of GnRH by human villi was studied by measuring liberated amino acids using high performance liquid chromatography. The GnRH degrading activity was 1.53 times higher after incubation with the membrane fraction of first trimester villi than that after incubation with the membrane fraction of term villi. Phosphoramidon, a potent inhibitor of NEP, reduced the liberated amino acids to about a half, suggesting that NEP is a responsible enzyme for GnRH degradation. Ubenimex, which can inhibit several aminopeptidases, also reduced the liberated amino acids to about 50 per cent. O-phenanthroline, EDTA, and thiorphan could inhibit GnRH degradation but inhibitors of post proline endopeptidase could not. Furthermore, GnRH degrading activity of the membrane fraction was reduced remarkably after the membrane fraction was immunotitrated by anti NEP and anti placental leucine aminopeptidase (P-LAP) IgG. In conclusion, NEP and P-LAP are responsible enzymes for GnRH degradation in human villi.

Relation between ultrasonographic and histologic findings of tracheal invasion by differentiated thyroid cancer.

Between 1988 and 1999 a total of 24 patients with differentiated thyroid cancer invading the airway underwent various types of tracheal resection at the Osaka Police Hospital. Preoperative ultrasonographic (US) findings in these patients were compared with postoperative histologic results of the resected specimens to confirm the relation between the preoperative and postoperative diagnoses and to determine the indications for operative procedures. Preoperative US revealed cancer invasion to the adventitia in 2 cases, to the intercartilage space in 13, and to the tracheal mucosa in 9. Histologically, cancer invasion to the adventitia was confirmed in 4, to the intercartilage space in 10, and to the mucosa in 10. Among 13 cancer invasion instances to the intercartilage revealed by US, overdiagnosis occurred in 3 cases and underdiagnosis in 1. The actual overall diagnostic rate by US was 83.3%, which is a great improvement over other available methods. In conclusion, preoperative US findings of the trachea agreed with the histologic findings of the resected specimens, indicating US to be the first choice when making decisions about resecting the trachea and about the operative procedure.

Progesterone stimulates the expression of aminopeptidase A/angiotensinase in human choriocarcinoma cells.

In human placenta aminopeptidase A (APA), a principal enzyme that converts angiotensin II to angiotensin III, seems to be involved in angiotensin II metabolism during pregnancy. In this study, we investigated the possible effects of progesterone and estrogen on APA mRNA and protein levels in choriocarcinoma cells as a model for placenta. By RNase protection assay, progesterone induced higher APA mRNA levels than estrogen at the same concentration. Progesterone exhibited dose-dependent stimulation of APA mRNA, 1.8-fold increase at 10(-6) m for 24 h treatment. Progesterone at 10(-6) m increased APA mRNA levels within 12 h and in time-dependent fashion up to 24 h. Fluorescence-activated cell sorting analysis and measurements of APA activities revealed the induction of APA protein by progesterone. Expression of progesterone receptors (PR) and glucocorticoid receptors (GR) were determined in these cells by RT-PCR, which suggested that the progesterone's actions might be displayed through PR and/or GR. These findings may serve as a useful model to study the effects of progesterone on angiotensin II metabolism in placenta, although the physiological validity of these studies remains to be clarified.

Expression of p57/Kip2 protein in pancreatic adenocarcinoma.

INTRODUCTION: Evaluation of the biologic character of carcinomas requires understanding of cell cycle regulators. AIMS: To investigate p57 expression in human pancreatic adenocarcinoma and cyst adenoma. METHODOLOGY: We examined the expression of p57(Kip2), a member of the Cip/Kip family, in 45 pancreatic adenocarcinomas, 7 cystadenomas, and 7 chronic pancreatitis cases. RESULTS: The p57 labeling index (LI) in duct epithelia in chronic pancreatitis averaged 32.8+/-8.3 and was significantly higher than in normal duct epithelia (18.8+/-6.6; p = 0.0011). For the carcinoma, the LI averaged 46.0+/-20.9, which was significantly higher than that for normal duct epithelia (p < 0.0001) and cystadenoma (16.0 11.2; p = 0.0007). However, it was significantly reduced in cases with stage IV disease (p = 0.0351), lymph node metastasis (p = 0.0003), larger size (p = 0.0094), capsular invasion (p = 0.0462), lymphatic invasion (p = 0.0351), and cell proliferating activity (p = 0.0002). In multivariate analysis, p57 LI in pancreatic adenocarcinoma was independently linked to high proliferating activity (p = 0.0230). CONCLUSION: These results suggest that p57 plays a role in the hyperplastic change of the ducts in chronic pancreatitis and that pS7 overexpression contributes to the downregulation of cell proliferation, and its decreased expression contributes to the progression of pancreatic adenocarcinoma.