Fabrication of electron beam deposited tip for atomic-scale atomic force microscopy in liquid

Recently, possibilities of improving operation speed and force sensitivity in atomic-scale atomic force microscopy (AFM) in liquid using a small cantilever with an electron beam deposited (EBD) tip have been intensively explored. However, the structure and properties of an EBD tip suitable for such an application have not been well-understood and hence its fabrication process has not been established. In this study, we perform atomic-scale AFM measurements with a small cantilever and clarify two major problems: contaminations from a cantilever and tip surface, and insufficient mechanical strength of an EBD tip having a high aspect ratio. To solve these problems, here we propose a fabrication process of an EBD tip, where we attach a 2 μm silica bead at the cantilever end and fabricate a 500-700 nm EBD tip on the bead. The bead height ensures sufficient cantilever-sample distance and enables to suppress long-range interaction between them even with a short EBD tip having high mechanical strength. After the tip fabrication, we coat the whole cantilever and tip surface with Si (30 nm) to prevent the generation of contamination. We perform atomic-scale AFM imaging and hydration force measurements at a mica-water interface using the fabricated tip and demonstrate its applicability to such an atomic-scale application. With a repeated use of the proposed process, we can reuse a small cantilever for atomic-scale measurements for several times. Therefore, the proposed method solves the two major problems and enables the practical use of a small cantilever in atomic-scale studies on various solid-liquid interfacial phenomena.

Polypeptide N-acetylgalactosaminyl transferase 3 independently predicts high-grade tumours and poor prognosis in patients with renal cell carcinomas

BACKGROUND

The polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts) family of enzymes regulates the initial steps of mucin-type O-glycosylation. N-acetylgalactosaminyltransferases might show novel patterns of GalNAc-T glycosylation on tumour-derived proteins, which could influence cancer biology, but its mechanisms are unclear. We investigated the association of GalNAc-T3 and -T6 expressions with clinicopathological features and prognoses of patients with renal cell carcinomas (RCCs).

METHODS

Expressions of GalNAc-T3/6 and cell-adhesion molecules were analysed immunohistochemically in 254 paraffin-embedded tumour samples of patients with RCC.

RESULTS

Of 138 GalNAc-T3+ cases, 46 revealed significant co-expression with GalNAc-T6. N-acetylgalactosaminyltransferases-3+ expression showed a close relationship to poor clinical performance and large tumour size, or pathologically high Fuhrman's grading, and presence of vascular invasion and necrosis. The GalNAc-T3-positivity potentially suppressed adhesive effects with a significantly low β-catenin expression. Univariate and multivariate analyses showed the GalNAc-T3+ group, but not the GalNAc-T6+ group, to have significantly worse survival rates.

CONCLUSION

N-acetylgalactosaminyltransferases-3 expression independently predicts high-grade tumour and poor prognosis in patients with RCC, and may offer a therapeutic target against RCC.

Bovine milk contains microRNA and messenger RNA that are stable under degradative conditions

We previously reported that microRNA (miRNA) is present in human breast milk. Recently, other groups have reported that bovine milk also contains miRNA; however, these reports are few. We therefore investigated bovine milk miRNA using microarray and quantitative PCR analyses to identify the differences between colostrum and mature milk. The RNA concentration in a colostrum whey fraction was higher than that in a mature milk whey fraction. In total, 102 miRNA were detected in bovine milk by microarray analysis (100 in colostrum and 53 in mature milk; 51 were common to both). Among these miRNA, we selected several immune- and development-related miRNA, including miR-15b, miR-27b, miR-34a, miR-106b, miR-130a, miR-155, and miR-223. These miRNA were detected in bovine milk by quantitative PCR, and each of these miRNA was significantly more highly expressed in colostrum than in mature milk. We also confirmed the presence of some mRNA in bovine milk. Nevertheless, synthesized miRNA spiked in the raw milk whey were degraded, and naturally existing miRNA and mRNA in raw milk were resistant to acidic conditions and RNase treatment. The RNA molecules in milk were stable. We also detected miRNA and mRNA in infant formulas purchased from Japanese markets. It is still unknown whether milk-derived RNA molecules play biological roles in infants; however, if milk-derived RNA do show functions in infants, our data will help guide future studies.

Prognostic significance of BAF57 expression in patients with endometrial carcinoma

This study was conducted to elucidate the prognostic significance of BAF57 in patients with endometrial carcinoma. We investigated the relationship between the immunohistochemical expression of BAF57 and various clinicopathological variables in 111 endometrial carcinomas. Both univariate and multivariate regression analyses were performed. The correlations between the BAF57 expression and the other variables including estrogen receptor (ER) and p53 were examined. The high nuclear BAF57 expression was detected in 42 (37.8%) endometrial carcinomas, and 69 (62.2%) endometrial carcinomas were defined as having low nuclear BAF57 expression. The BAF57 expression was significantly associated with the surgical stage, grade of the tumor, myometrial invasion, lympho-vascular space invasion (LVSI) and lymph node metastasis. The 10-year overall survival rates of patients with low and high BAF57 expression were 96.9% and 58.2%, respectively (p<0.001). A multivariate analysis identified BAF57 expression as an independent prognostic factor. The BAF57 expression was significantly correlated with p53 expression (r=0.312, P=0.001), but was not correlated with ER expression (r= -0.141, P=0.14). The high BAF57 expression is an independent marker of poor prognosis of the patients in endometrial carcinomas. The inhibition of BAF57 activity may be one of the candidates for endometrial cancer therapy, especially therapy for aggressive tumors showing overexpression of p53.

P4-01-15: Alteration of Y-box Binding Protein-1 Expression Modifies the Response to Endocrine Therapy in Estrogen Receptor Positive Breast Cancer

Y-box binding protein-1 (YB-1) plays an important role in tumor progression and drug resistance. This study examined whether YB-1 is involved in the alteration of response to endocrine therapy in ER-positive breast cancer cells. MCF7 cells that stably expressed YB-1 (MCF7-YB-1) and vector control cells (MCF7-vector) were established. These cells were used to analyze the expression of the factors related to the ER and growth factor receptor signaling pathways, response to the antiestrogens (tamoxifen and fulvestrant), and estrogen responsive element (ERE) activity. The effect of knocking down endogenous YB-1 expression was tested in wild-type MCF7 cells. In addition, the expression of the YB-1 and the factors related to the ER and growth factor receptor signaling pathways were evaluated in the clinical breast cancers treated with preoperative chemotherapy. The expression of HER2, AIB1, p-Erk and c-Myc were increased in the MCF7-YB-1 cells. In contrast, knocking down of YB-1 decreased the expression of these factors, but increased the expression of ERα in the wild-type MCF7 cells. Furthermore, sensitivity to antiestrogens was decreased in the MCF7-YB-1 in comparison to those in the MCF7-vector cells. In the MCF7-YB-1 cells, the expression levels of p-Erk and c-Myc were continuously upregulated when the cells were treated either with tamoxifen or fulvestrant. The ERE activity was decreased in the MCF7-YB-1 cells in comparison to the MCF7-vector cells, and the ERE activity of the MCF7-YB-1 cells was inhibited by fulvestrant at a lower concentration than that which inhibited the ERE activity of the MCF7-vector cells. In the ER-positive clinical breast cancers treated with preoperative chemotherapy, significantly more of the specimens that showed increased or positive nuclear YB-1 expression after the chemotherapy were positive for HER2 expression. These data suggest that alteration of YB-1 may modify the crosstalk between the ER pathway and HER2 pathway in ER-positive breast cancer cells, and consequently may alter the response to endocrine therapy in these cells.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-01-15.

Polypeptide N-acetylgalactosaminyltransferase 6 expression in pancreatic cancer is an independent prognostic factor indicating better overall survival

BACKGROUND

The family of polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts) is responsible for the altered glycosylation in cancer. The purpose of our study was to investigate the clinical significance of two isoforms, GalNAc-T6 and -T3, and their correlation with the prognosis of pancreatic cancer.

METHODS

Immunohistochemistry was used to analyse GalNAc-T6 and -T3 expressions in 70 clinicopathologically characterised pancreatic cancer cases.

RESULTS

Positive expressions of GalNAc-T6 and -T3 were immunohistochemically identified in 51% (36 of 70) and in 77% (54 of 70) of patients, respectively. A close relationship was noted between GalNAc-T6 positive expression and pathological well/moderate differentiated type (P=0.001), small tumour size (P=0.044), absence of vascular invasion (P=0.009), and low stage of the American Joint Committee on Cancer systems (P=0.043). The expression of GalNAc-T3 significantly correlated with good differentiation (P=0.001), but not with other clinicopathologic features. Furthermore, univariate and multivariate analyses revealed that GalNAc-T6 expression was an independent prognosis indicator for the disease, whereas GalNAc-T3 expression had no impact on clinical outcome, even though 33 of 36 GalNAc-T6-positive cases also had a positive expression of GalNAc-T3 (P=0.001, r=0.356).

CONCLUSION

Both GalNAc-T6 and -T3 expressions correlated significantly with tumour differentiation, whereas only GalNAc-T6 expression predicted prognosis in pancreatic cancer.

[Direct instillation of the fibrin glue into the ruptured bulla is an effective treatment for uncontrolled pneumothorax occurred from severe emphysematous bullae]

From May 2005 to October 2010. 9 patients with severe emphysematous bullae suffered from uncontrolled pneumothorax had been successfully treated by a new surgical method in our hospital. By using direct instillation of fibrin glue into the ruptured bulla following ligation of the ruptured bulla hole, 8 of 9 patients revealed no recurrence of new rupture and pneumothorax. Although the ligation of ruptured bulla hole tended to increase tension of surface of the bulla around the ligation and caused new rupture of the bulla, the fully instilled glue reduced intra air pressure of the ligated bulla and prevented new rupture. Additionally, the direct instillation of the glue immediately stopped the air leakage by itself. This direct instillation method of the glue encouraged us to challenge the surgery for the patients suffered from uncontrolled pneumothorax with severe emphysematous bullae.

Increased Nuclear Localization of Transcription Factor Y-Box Binding Protein 1 Accompanied by Up-Regulation of P-Glycoprotein in Breast Cancer Pretreated with Paclitaxel

Purpose: The Y-box binding protein 1 (YB-1) regulates expression of P-glycoprotein (P-gp) encoded by the MDR1 gene. There have been no previous studies regarding the involvement of YB-1 in the development of resistance to paclitaxel. The present study was performed to examine how paclitaxel affects the localization and expression of YB-1 in breast cancer.Experimental Design: We evaluated the expression and localization of YB-1 and P-gp in breast cancer tissues obtained from 27 patients before and after treatment with paclitaxel. The effect of paclitaxel on localization of cellular YB-1 was examined by using GFP-YB-1. Interaction of YB-1 with the Y-box motif of the MDR1 promoters was studied by EMSA. The effects of paclitaxel on MDR1 promoter activity were examined by luciferase assay.Results: Of 27 breast cancer tissues treated with paclitaxel, nine (33%) showed translocation of YB-1 from the cytoplasm to the nucleus together with increased expression of P-gp during the course of treatment. Twelve breast cancer tissues (44%) showed neither translocation of YB-1 nor increased expression of P-gp. Nuclear translocation of YB-1 was correlated significantly with increased expression of P-gp (P=0.0037). Confocal analysis indicated that paclitaxel induced nuclear translocation of green fluorescent fused YB-1 in MCF7 cells. Furthermore, binding of YB-1 to the Y-box of MDR1 promoter was increased in response to treatment with paclitaxel. In addition, MDR1 promoter activity was significantly up-regulated by paclitaxel in MCF7 cells (p&lt; 0.001).Conclusions: The results of the present study suggested that YB-1 may be involved in the development of resistance to paclitaxel in breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1141.

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.