BubR1 localizes to centrosomes and suppresses centrosome amplification via regulating Plk1 activity in interphase cells

BubR1 is a critical component of the mitotic checkpoint that delays the onset of anaphase until all chromosomes have established bipolar attachment to the microtubules. We previously reported that mutations of the BUB1B gene (encoding BubR1) caused premature chromatid separation (PCS) syndrome, a condition characterized by constitutional aneuploidy and a high risk of childhood cancer. We here report that the cells from PCS syndrome patients have loss of regulation of the centrosome duplication machinery, resulting in centrosome amplification and multipolar mitosis. PCS syndrome cells show increased activity of Polo-like kinase 1 (Plk1), whose knockdown suppresses centrosome amplification. BubR1 localizes to centrosomes, physically interacts with Plk1 and inhibits Plk1 phosphorylation and its kinase activity during interphase. These results unravel a crucial role of BubR1 in preventing centrosome reduplication through negative regulation of Plk1 in interphase cells.

Clinical usefulness of mtTFA expression as a predictive marker in colorectal cancer patients treated with FOLFOX

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Background: We previously reported that mitochondrial transcription factor A (mtTFA; also designated Tfam) preferentially recognizes cisplatin-damaged DNA via physical interaction with p53 and is upregulated by the treatment with cisplatin and 5-FU (Yoshida et al, Cancer Res. 2003). The aim of this study was to evaluate whether expression of mtTFA predicts clinical outcome in patients with metastatic colorectal cancer treated with modified FOLFOX6 (mFOLFOX6). Methods: From January 2006 to April 2008, 59 patients who had metastatic lesions from colorectal cancer treated with mFOLFOX6 at the Osaka Rosai Hospital were included in this study. They consisted of 25 women (42.4%) and 34 men (57.6%), with a median age of 62 years (29–84). Patients were treated with oxaliplatin 85mg/m2 plus leucovorin 200mg/m2 as a 2-h infusion at day 1, followed by 5-FU bolus 400mg/m2 and 46-h continuous infusion of 2400 mg/m2. Treatment was repeated in 2-week intervals for at least 4 cycles. The expressions of mtTFA and p53 of resected primary tumors were examined by immunohistochemistry. Results: Among 59 patients, one complete response and 32 partial responses were observed (response rate, 55.9%) . The positive rates was 44.1% (26/59; CR 1, PR 7, SD/PD 18) for mtTFA and 59.3% (35/59; CR 1, PR 19, SD/PD 15) for p53, respectively. Strong expression of mtTFA was detected in 8 of 33 CR/PR (24.2%) and in 18 of 26 SD/PD (69.2%), indicating that the expression of mtTFA correlated significantly with response to chemotherapy (P<0.01). On the other hand, there was no significant correlation between response to chemotherapy and p53 expression (P=0.82). mtTFA expression was significantly associated with overall survival (P=0.036) and progression free survival (P=0.037). Multivariate analysis revealed that mtTFA expression significantly impacted on OS (Hazard ratio 2.10, P=0.036). Conclusions: Immunohistochemical study of mtTFA may be useful in prediction of the clinical outcome of metastatic colorectal cancer patients treated with FOLFOX.

No significant financial relationships to disclose.

Sanitation and Microbiological Quality in Production Field and Fruit-Packing Shed of Persimmon and Satsuma Mandarin in Japan

The effects of sanitation treatments including chlorination (ca 10 ppm available chlorine) of agricultural water and ethyl alcohol (70%) spraying on packing shed equipment on microbial contamination on fruits and the environment were determined and compared with those in conventionally managed field and packing shed in persimmon and satsuma mandarin orchards. Chlorinated water reduced the microbial counts to levels below the lower limit of detection (1.4 log CFU/ml for bacteria and 2.0 log CFU/ml for fungi) in most agricultural water samples. Microbial counts of pesticide solution, which contained the agricultural water or chlorinated water for the mixture, were lower in sanitary field than in control field in both fruit orchards. The number of bacterial and mold species detected in agricultural water, chlorinated water, and pesticide solution were almost proportional to microbial counts in each sample throughout the year. The chlorination treatment of agricultural water tended to reduce the counts of mesophiles and fungi on the peel of persimmon fruit during production season. The ethyl alcohol spray treatment on packing shed equipment resulted in a substantial microbial reduction on plastic harvest basket and container in persimmon orchard and plastic harvest basket and container, gloves, scissors, and size sorter in satsuma mandarin orchard. The spray application on packing shed equipment reduced the counts of mesophiles and fungi on the peel of persimmon fruit by >1 log CFU/g. The number of satsuma mandarin packing shed equipment containing the species found on fruit peel was higher in control than in sanitary packing shed. No human pathogens such as verotoxin-producing Escherichia coli and Salmonella were detected in any of the fruit and environmental samples. These results indicate that uses of sanitizers such as chlorine for agricultural water and ethyl alcohol for packing shed equipment would be useful in a good agricultural practices program of persimmons and satsuma mandarin.

Potential sources of microbial contamination of satsuma mandarin fruit in Japan, from production through packing shed

Potential sources of microbial contamination of satsuma mandarin fruit were investigated from production through the packing shed in the 2005 season. Microbial counts in the peel and flesh during the fruit development stage were below 2.4 log CFU/g for bacteria and 3 log CFU/g for fungi, except for the peel in August and September. In the field environment, the highest microbial counts were found in fallen leaves on the ground, followed by soil, organic fertilizer, and agricultural water. Only the pesticide solution collected in July was positive for Salmonella, while no verotoxin-producing Escherichia coli was detected from any of the samples. The bacterial and mold flora in the peel comprised phytopathogenic organisms such as bacteria genus Pantoea and mold genus Mycosphaerella and soilborne organisms such as bacteria genus Bacillus and mold genus Cladosporium, which were found in soil, fallen leaves, agricultural water, and cloth mulch throughout the production season. After fruit harvest and sorting, microbial counts of the peel increased, while those of the flesh remained below the lower limit of detection. Although some of the preharvest sources could also be postharvest sources, some packing shed equipment was assumed to be postharvest sources, because Bacillus cereus was not identified from the fruit in the production field but was detected on the peel after sorting and on equipment such as gloves, plastic harvest basket, and size sorter. These results suggest that using sanitizers for agricultural water and packing sheds to prevent cross-contamination would be useful in a good agricultural practices program of the satsuma mandarin in Japan.

Centrosome amplification induced by survivin suppression enhances both chromosome instability and radiosensitivity in glioma cells

Glioblastoma is characterised by invasive growth and a high degree of radioresistance. Survivin, a regulator of chromosome segregation, is highly expressed and known to induce radioresistance in human gliomas. In this study, we examined the effect of survivin suppression on radiosensitivity in malignant glioma cells, while focusing on centrosome aberration and chromosome instability (CIN). We suppressed survivin by small interfering RNA transfection, and examined the radiosensitivity using a clonogenic assay and a trypan blue exclusion assay in U251MG (p53 mutant) and D54MG (p53 wild type) cells. To assess the CIN status, we determined the number of centrosomes using an immunofluorescence analysis, and the centromeric copy number by fluorescence in situ hybridisation. As a result, the radiosensitisation differed regarding the p53 status as U251MG cells quickly developed extreme centrosome amplification (=CIN) and enhanced the radiosensitivity, while centrosome amplification and radiosensitivity increased more gradually in D54MG cells. TUNEL assay showed that survivin inhibition did not lead to apoptosis after irradiation. This cell death was accompanied by an increased degree of aneuploidy, suggesting mitotic cell death. Therefore, survivin inhibition may be an attractive therapeutic target to overcome the radioresistance while, in addition, proper attention to CIN (centrosome number) is considered important for improving radiosensitivity in human glioma.

On-farm sources of microbial contamination of persimmon fruit in Japan

Potential sources of microbial contamination for persimmon fruit during growing and harvesting in the 2005 season were investigated to provide a baseline to design the good agricultural practices program for persimmons in Japan. Microbial counts in the peel of persimmon fruit during production season were close to or below 2.4 log CFU/g for bacteria and 3.0 log CFU/g for fungi but were above these values on harvested fruit. The counts in the flesh were below the detection level with all fruit. Bacteria and molds isolated from peel and flesh of persimmons during growing were phytopathogenic and soilborne organisms such as bacteria genera Enterobacter and Bacillus and mold genera Fusarium and Cladosporium, which were found in soil, weeds, agricultural water, and pesticide solution throughout the production season. The agricultural water was one of the most important potential preharvest sources, because Escherichia coli O157:H7 was identified from agricultural water in May, and Salmonella was detected in agricultural water, pesticide solution containing the agricultural water for the mixture, and soil after application of the pesticide solution in June. Neither of the two pathogenic bacteria was detected in any of the fruit samples. Microbial counts and diversity in the peel of persimmons at harvest increased after contact with plastic harvest basket and container, which could be sources of contamination during harvesting. Therefore, monitoring and management on-farm should focus on agricultural water and harvest equipment as important control points to reduce microbial contamination on persimmons.

Occurrence of parasympathetic vasodilator fibers in the lower lip of the guinea-pig

The present study was designed to examine whether there are parasympathetic vasodilator fibers in the lower lip of the guinea-pig. Electrical stimulation of the central cut end of the lingual nerve of guinea-pigs evoked intensity- and frequency-dependent decreases in lower lip blood flow and systemic arterial blood pressure (SABP). Pretreatment with guanethidine, a postganglionic sympathetic nerve blocker and antihypertensive drug (30 mg kg(-1), s.c., 24 h prior to experiments), reduced the magnitude of the decrease in SABP while the intensity- and frequency-dependent increases of the lip blood flow occurred by the lingual nerve stimulation only on the side ipsilateral to stimulation. Increases in the lip blood flow evoked by lingual nerve stimulation in guanethidine pretreated guinea-pigs were reduced by hexamethonium (an autonomic ganglion cholinergic blocker) in a dose-dependent manner. When fluoro-gold (a retrograde neural tracer) was injected into the lower lip, labeled neurons were observed in the ipsilateral otic ganglion. The present study indicates the presence of parasympathetic vasodilator fibers originating from the otic parasympathetic ganglion in the guinea-pig lower lip, similar to those reported previously in rats, cats, rabbits and humans.

ZNF143 interacts with p73 and is involved in cisplatin resistance through the transcriptional regulation of DNA repair genes

Zinc-finger protein 143 (ZNF143) is a human homolog of Xenopus transcriptional activator staf that is involved in selenocystyl tRNA transcription. We previously showed that ZNF143 expression is induced by treatment with DNA-damaging agents and that it preferentially binds to cisplatin-modified DNA. In this study, the potential function of ZNF143 was investigated. ZNF143 was overexpressed in cisplatin-resistant cells. ZNF143 knockdown in prostate cancer caused increased sensitivity for cisplatin, but not for oxaliplatin, etoposide and vincristine. We also showed that ZNF143 is associated with tumor suppressor gene product p73 but not with p53. p73 could stimulate the binding of ZNF143 to both ZNF143 binding site and cisplatin-modified DNA, and modulate the function of ZNF143. We provide a direct evidence that both Rad51 and flap endonuclease-1 are target genes of ZNF143 and overexpressed in cisplatin-resistant cells. Taken together, these experiments demonstrate that an interplay of ZNF143, p73 and ZNF143 target genes is involved in DNA repair gene expression and cisplatin resistance.

Clock and ATF4 transcription system regulates drug resistance in human cancer cell lines

The mechanisms underlying cellular drug resistance have been extensively studied, but little is known about its regulation. We have previously reported that activating transcription factor 4 (ATF4) is upregulated in cisplatin-resistant cells and plays a role in cisplatin resistance. Here, we find out a novel relationship between the circadian transcription factor Clock and drug resistance. Clock drives the periodical expression of many genes that regulate hormone release, cell division, sleep-awake cycle and tumor growth. We demonstrate that ATF4 is a direct target of Clock, and that Clock is overexpressed in cisplatin-resistant cells. Furthermore, Clock expression significantly correlates with cisplatin sensitivity, and that the downregulation of either Clock or ATF4 confers sensitivity of A549 cells to cisplatin and etoposide. Notably, ATF4-overexpressing cells show multidrug resistance and marked elevation of intracellular glutathione. The microarray study reveals that genes for glutathione metabolism are generally downregulated by the knockdown of ATF4 expression. These results suggest that the Clock and ATF4 transcription system might play an important role in multidrug resistance through glutathione-dependent redox system, and also indicate that physiological potentials of Clock-controlled redox system might be important to better understand the oxidative stress-associated disorders including cancer and systemic chronotherapy.

Akt-dependent nuclear localization of Y-box-binding protein 1 in acquisition of malignant characteristics by human ovarian cancer cells

Y-box-binding protein 1 (YB-1), which is a member of the DNA-binding protein family containing a cold-shock domain, has pleiotropic functions in response to various environmental stimuli. As we previously showed that YB-1 is a global marker of multidrug resistance in ovarian cancer and other tumor types. To identify YB-1-regulated genes in ovarian cancers, we investigated the expression profile of YB-1 small-interfering RNA (siRNA)-transfected ovarian cancer cells using a high-density oligonucleotide array. YB-1 knockdown by siRNA upregulated 344 genes, including MDR1, thymidylate synthetase, S100 calcium binding protein and cyclin B, and downregulated 534 genes, including CXCR4, N-myc downstream regulated gene 1, E-cadherin and phospholipase C. Exogenous serum addition stimulated YB-1 translocation from the cytoplasm to the nucleus, and treatment with Akt inhibitors as well as Akt siRNA and integrin-linked kinase (ILK) siRNA specifically blocked YB-1 nuclear localization. Inhibition of Akt activation downregulated CXCR4 and upregulated MDR1 (ABCB1) gene expression. Administration of Akt inhibitor resulted in decrease in nuclear YB-1-positive cancer cells in a xenograft animal model. Akt activation thus regulates the nuclear translocation of YB-1, affecting the expression of drug-resistance genes and other genes associated with the malignant characteristics in ovarian cancer cells. Therefore, the Akt pathway could be a novel target of disrupting the nuclear translocation of YB-1 that has important implications for further development of therapeutic strategy against ovarian cancers.

Effects of isoflurane on parasympathetic vasodilatation in the rat submandibular gland

Volatile anesthetics have been known to suppress parasympathetic reflex vasodilatation in the lower lip and palate. However, in the submandibular gland, little is known about the effects of these anesthetics on the parasympathetic vasodilatation elicited by reflex and direct (i.e., non-reflex) activation of the parasympathetic vasodilator mechanisms. Although both parasympathetic vasodilatations were inhibited by isoflurane in a concentration- and time-dependent manner, the effects of continuous administration of the alpha(1)-adrenoceptor agonist methoxamine were markedly different: The reflex vasodilatation was not affected by methoxamine, while the direct vasodilatation was significantly reduced. Picrotoxin (GABA(A) receptor antagonist) attenuated the inhibitory effect of isoflurane on direct vasodilatation and the systemic arterial blood pressure. These findings suggest that the isoflurane-induced inhibitory effects on direct vasodilatation are produced by a decrease of peripheral vascular tone by GABAergic mechanisms, whereas those on the reflex vasodilatation are produced exclusively by the inhibition of the reflex center.

Mortalin controls centrosome duplication via modulating centrosomal localization of p53

Abnormal amplification of centrosomes, commonly found in human cancer, is the major cause of mitotic defects and chromosome instability in cancer cells. Like DNA, centrosomes duplicate once in each cell cycle, hence the defect in the mechanism that ensures centrosome duplication to occur once and only once in each cell cycle results in abnormal amplification of centrosomes and mitotic defects. Centrosomes are non-membranous organelles, and undergo dynamic changes in its constituents during the centrosome duplication cycle. Through a comparative mass spectrometric analysis of unduplicated and duplicated centrosomes, we identified mortalin, a member of heat shock protein family, as a protein that associates preferentially with duplicated centrosomes. Further analysis revealed that mortalin localized to centrosomes in late G1 before centrosome duplication, remained at centrosomes during S and G2, and dissociated from centrosomes during mitosis. Overexpression of mortalin overrides the p53-dependent suppression of centrosome duplication, and mortalin-driven centrosome duplication requires physical interaction between mortalin and p53. Moreover, mortalin promotes dissociation of p53 from centrosomes through physical interaction. The p53 mutant that lacks the ability to bind to mortalin remains at centrosomes, and suppresses centrosome duplication in a transactivation function-independent manner. Thus, our present findings not only identify mortalin as an upstream molecule of p53 but also provide evidence for the involvement of centrosomally localized p53 in the regulation of centrosome duplication.

Expression of Y-box-binding protein dbpC/contrin, a potentially new cancer/testis antigen

Y-box-binding proteins are members of the human cold-shock domain protein superfamily, which includes dbpA, dbpB/YB-1, and dbpC/contrin. dbpC/contrin is a germ cell-specific Y-box-binding protein and is suggested to function as a nuclear transcription factor and RNA-binding protein in the cytoplasm. Whereas ubiquitous dbpB/YB-1 expression has been well studied in various types of human carcinomas as a prognostic or predictive marker, the dbpC/contrin expression in human tumour cells has not been reported. In this report, we provide the first evidence showing that dbpC was highly expressed in human testicular seminoma and ovarian dysgerminomas, and in carcinomas in other tissues and that its expression in normal tissues is nearly restricted to germ cells and placental trophoblasts. These results indicate that dbpC/contrin would be a potentially novel cancer/testis antigen.

Measurement of a long electronic spin relaxation time of cesium atoms in superfluid helium

The longitudinal electronic spin relaxation time of Cs atoms optically polarized in superfluid helium (He II, 1.5 K) has been measured with special care to cope with a serious decrease in the number of Cs atoms in the observation region. This decrease, mainly caused by helium convection in introducing the atoms into He II by laser sputtering, was significantly reduced using a new atom implantation method. Combined with a careful correction for the number of atoms, we have determined the relaxation time to be 2.24(19) s or longer, roughly twice as long as that in solid He.

Suppression of inferior alveolar nerve-induced vasoconstrictor response by ongoing cervical sympathetic nerve activity in cat

We examined the effects of ongoing cervical sympathetic trunk (CST) stimulation on the vasoconstrictor responses in the lower lip elicited by electrical stimulation (ES) of the inferior alveolar nerve (IAN) or CST in anaesthetised cats to determine whether (i) the previously reported suppressive effect of ongoing CST activity on IAN-induced vasoconstriction occurs during not only ipsilateral, but also contralateral CST stimulation; and (ii) a vasoconstriction can be elicited by brief CST stimulation during ongoing stimulation of the contralateral CST. The central lower lip blood vessels are innervated by both left and right CST. The fall in central lip blood flow (LBF) elicited by IAN stimulation alone was reduced in a frequency-dependent manner during concurrent CST stimulation at 0.2-2 Hz, and at the high end of this frequency range was transformed to a rise regardless of whether the CST stimulation was ipsilateral or contralateral to the IAN stimulation. The fall in central LBF elicited by stimulation of one CST was not transformed to a rise by ongoing stimulation of the contralateral CST. Possibly, IAN-evoked orofacial vasoconstriction does not occur under physiological conditions (unlike IAN-evoked vasodilatation) because it is suppressed by the spontaneous sympathetic discharge in CST.

1-Azaadamantanes: pharmacological applications and synthetic approaches

1-Azaadamantane (1-azatricyclo [3.3.1.1(3,7)]decane) was synthesized in 1953, and the derivatives have been used as rigid models for studies on intramolecular charge transfer phenomena, fluorescence excitation Rydberg states, highly twisted amides, solid electrolyte gas sensors, basicities, and self-organization systems. These structures have also been attracting considerable interest due to their pharmacological activities. The substituted 1-azaadamantanes as conformationally restricted amines have great potential for the therapeutic utilization as anticholinergic agents, serotonergic agents, and squalene synthase inhibitors. However, many steps have been needed for the synthesis of 1-azaadamantanes, and the concise synthetic approaches have been developed. Though double or triple Mannich reactions yield 1-azaadamantanes in moderate yields, the reduction steps are necessary. Our recent research has revealed that trifluoromethanesulfonic anhydride is available for the convenient synthesis of 1-azoniaadamantanes and 1-azaadamantanes without reduction. The new tools for the discovery of novel drugs such as quantitative structure-activity relationship (QSAR) analysis and vibrational circular dichroism (VCD) spectroscopy have also been discussed.

Low expression of polypeptide GalNAc N-acetylgalactosaminyl transferase-3 in lung adenocarcinoma: impact on poor prognosis and early recurrence

Initial glycosylation of mucin-type O-linked protein is catalysed by one of the UDP-GalNAc: polypeptide N-acetyl-galactosaminyl transferase-3 (GalNAc-T3). O-glycosylation is important in the binding of cell adhesion molecules, cell differentiation, invasion, and metastasis in tumours. This study was designed to detect GalNAc-T3 expression in lung adenocarcinoma by using immunohistochemical staining, and to evaluate the relationship between the GalNAc-T3 expression level and prognosis and recurrence in completely resected lung adenocarcinoma patients. A low expression of GalNAc-T3 was detected in the cytoplasm of tumour cells in 79 of 148 patients (53.4%) with lung adenocarcinoma. The low expression of GalNAc-T3 was associated with poorly differentiated tumour (P<0.0001), poor pathologic stage (P<0.0001), lymph node metastasis (P<0.0001), and tumour recurrence (P=0.016). The lung carcinoma patients with low GalNAc-T3 expression had a poorer prognosis than those with high GalNAc-T3 expression, using both univariate and multivariate analyses (overall survival: P<0.0001 and P=0.011, respectively). In addition, multivariate analysis of the clinicopathological characteristics of stage I lung adenocarcinoma indicated that the low expression of GalNAc-T3 was a significant independent factor for predicting poor prognosis and early recurrence (P=0.006, rr=2.87 and P=0.019, rr=3.05, respectively). The low expression of GalNAc-T3 may be a useful marker for predicting poor prognosis and early recurrence in completely resected lung carcinoma patients, particularly patients with stage I diseases.