Design of charge exchange recombination spectroscopy for the joint Texas experimental tokamak

The old diagnostic neutral beam injector first operated at the University of Texas at Austin is ready for rejoining the joint Texas experimental tokamak (J-TEXT). A new set of high voltage power supplies has been equipped and there is no limitation for beam modulation or beam pulse duration henceforth. Based on the spectra of fully striped impurity ions induced by the diagnostic beam the design work for toroidal charge exchange recombination spectroscopy (CXRS) system is presented. The 529 nm carbon VI (n = 8 - 7 transition) line seems to be the best choice for ion temperature and plasma rotation measurements and the considered hardware is listed. The design work of the toroidal CXRS system is guided by essential simulation of expected spectral results under the J-TEXT tokamak operation conditions.

Abstract 2341: CAPG improves breast cancer metastasis through competing with PRMT5 to activate STC-1 transcription

Recent studies have shown that over-expression of macrophage-capping protein (CapG)improves cancer cell metastasis. Previously, we demonstrated that CAPG was highly expressed in MDA-MB-231 cell line with high metastatic potency compared with its maternal cell line. Sequencing of CapG-cDNA complex showed some overlap with the sequence of a group of DNA-binding proteins, the basic helix-loop-helix family, including the c-myc oncogene. We supposed that CAPG inhibited cancer cell metastasis through modulating gene transcription as a transcription factor.

To examine whether CAPG played a functional role in breast cancer metastasis, three kinds of breast cancer cell lines were applied, including overexpression and knockdown of CAPG. Total RNA from MCF-7 CAPG overexpression cells versus control was obtained. Microarray analysis of global genomic changes was conducted in transcriptional level of these cells. Stanniocalcin 1 (stc-1), an oncogene, was observed significantly up-regulated by over expression of CAPG. Mass spectra and co-immunopreciptation were used to find the potential transcription factors of CAPG.

In breast cancer cell lines, we found that CAPG expression is much higher in relatively aggressive cell line than the mild-nature one on both RNA and protein level. CAPG is also higher in cancer tissues than its adjacent noncancerous tissues (ANCT). Furthermore, it was confirmed that CAPG could directly bind to the promoter of stc-1 to activate stc-1 transcription by luciferase report assay and chip experiments. In CAPG overexpression cell line, knock-down of stc-1 could restrain the CAPG-induced migration and invasion. Interestingly, protein arginine methyltransferase 5 (PRMT5) was found as transcription repressor to compete with CAPG in modulating stc-1 transcription.

In this study, CAPG was approved to play a direct role in participating transcription for the first time. We also supposed that by combining with PRMT5, CAPG could compete with PRMT5, and prevent PRMT5 from repressing stc-1 transcriptional process.

Citation Format: Sheng Huang, Yayun Chi, Jingyan Xue, Zhimin Shao, Zhaohui Wu, Jiong Wu. CAPG improves breast cancer metastasis through competing with PRMT5 to activate STC-1 transcription. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2341. doi:10.1158/1538-7445.AM2014-2341

CDK11p58 inhibits ERα-positive breast cancer invasion by targeting integrin β3 via the repression of ERα signaling

Background

CDK11^p58, a Ser/Thr kinase that belongs to the cell division cycle 2-like 1 (CDC2L1) subfamily, is associated with cell cycle progression, tumorigenesis and apoptotic signaling. CDK11^p58 is also involved in the regulation of steroid receptors, such as androgen and estrogen receptors. We previously found that CDK11^p58 was abnormally expressed in prostate cancer. However, its role in breast cancer remains unclear.

Methods

CDK11^p58 expression was evaluated by immunohistochemical staining in a tissue array. A Transwell assay was used to detect invasion and metastasis in breast cancer cells. The TaqMan® Metastasis Gene Expression Assay was used to search for potential downstream factors in the CDK11^p58 signaling pathway. qRT-PCR was used to evaluate mRNA levels, and the dual luciferase array was used to analyze promoter activity. Western blotting was used to detect the protein level.

Results

CDK11^p58 expression was negatively correlated with node status (P = 0.012), relapse status (P = 0.002) and metastasis status (P = 0.023). Kaplan-Meier survival curves indicated that the disease-free survival (DFS) was significantly poor in breast cancer patients with low CDK11 expression. Interestingly, using the breast cancer cell lines ZR-75-30 and MDA-MB-231, we found that CDK11^p58 was capable of repressing the migration and invasion of ERα-positive breast cancer cells, but not ERα-negative breast cancer cells, in a kinase-dependent manner. Gene expression assays demonstrated that integrin β3 mRNA was dramatically repressed by CDK11^p58, and luciferase results confirmed that the integrin β3 promoter was inhibited by CDK11^p58 through ERα repression. The expression of integrin β3 was highly related to ERα signaling; ERα overexpression stimulated integrin β3 expression, whereas siRNA-mediated knockdown of ERα attenuated integrin β3 expression.

Conclusions

These data indicate that CDK11^p58 is an anti-metastatic gene in ERα-positive breast cancer and that the regulation of integrin β3 by CDK11^p58 via the repression of ERα signaling may constitute part of a signaling pathway underlying breast cancer invasion.

Abnormal expression of CDK11p58 in prostate cancer

Background

CDK11^p58 is one of the large families of p34cdc2-related kinases whose functions are linked with cell cycle progression, tumorigenesis and apoptotic signaling. Our previous investigation demonstrated that CDK11^p58 repressed androgen receptor (AR) transcriptional activity and was involved in the negative regulation of AR function.

Methods

CDK11^p58 expression was examined in the prostate cancer tissues and adjacent tissues by IHC and qRT-PCR. Cell apoptosis was detected by flow cytometry. The metastasis of cancer cells was evaluated by the Transwell Assay. Finally we further investigated the underlying molecular mechanisms by examining expression levels of relevant proteins using western blot analysis.

Results

We found that both RNA and protein expression of CDK11^p58 were low in prostate cancer tissues compared with its adjacent noncancerous tissues. CDK11^p58 promoted the prostate cancer cell apoptosis and inhibited its metastasis in a kinase dependent way. And finally CDK11^p58 could inhibit the metastasis of AR positive prostate cancer cells through inhibition of integrin β3 and MMP2.

Conclusions

These data indicate that CDK11^p58 is an anti-metastasis gene product in prostate cancer.

Abstract P4-07-13: High microRNA-621 level predicts a better response to neoadjuvant chemotherapy in breast cancer patients

Purpose: Weekly paclitaxel plus carboplatin (PCb) regimen is an effective neoadjuvant chemotherapy for breast cancer. However, some patients respond to this regimen poorly and suffer from side effects. In this study, we aimed to define the microRNA (miRNA) biomarker for predicting sensitivity to PCb chemotherapy in breast cancer patients, and to explore the potential molecular mechanisms.

Experimental Design: 81 patients with stages II and III breast cancer, who received four cycles of weekly PCb regimen preoperative chemotherapy, were included. Gene expression profiles from 31 patients was used as training set to determine differentially expressed genes (DEGs) and to predict miRNAs that may be associated with chemotherapeutic sensitivity. The other 50 patients were analyzed as validation set to test the accuracy of DEG identification and miRNAs prediction by quantitative real-time PCR. In parallel, in vitro and in vivo analyses were carried out to determine the potential mechanisms of miRNA-dependent drug sensitivity.

Results: Gene profiling analyses in the training set revealed significant correlation between high expression level of miR-345 and miR-621 and pathologic complete response (pCR) in breast cancer patients. We further validated that the expression level of miR-621 was significantly higher in tumor tissues of pCR patients than that in non-pCR patients (P = 0.01). In breast cancer cell lines, ectopic overexpression of miR-621 promoted apoptosis and increased chemosensitivity to paclitaxel and carboplatin both in vitro and in vivo. The potential miR-621-target genes were determined by TargetScan and miRNA CLIP-seq database, which were further confirmed as DEGs reversely-correlated to miR-621 in breast cancer patient samples. Among those, FBXO11 was verified as one of the direct targets of miR-621 in breast cancer cells, whose expression level negatively associated with chemosensitivity in breast cancer patients. The molecular mechanisms by which miR-621/FBXO11 axis regulates chemosensitivity may involve regulation of p53 transcriptional activity and epithelial-mesenchymal transition (EMT) in breast cancer cells.

Conclusions: Our study revealed a strong correlation between miR-621 expression and chemosensitivity in breast cancers. High level of miR-621 predicts sensitivity to PCb regimen neoadjuvant chemotherapy in breast cancer patients who tend to achieve pCR. The increased chemosensitivity may be mediated by down-regulation of FBXO11 gene, which leads to enhanced p53 transactivity and reduced EMT in breast cancer cells. Therefore, miR-621 may be used as predictive biomarker and the potential therapeutic target in breast cancer treatment.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-07-13.

Abstract P5-04-11: CDK11p58 inhibits estrogen receptor a positive breast cancer invasion via integrinb3 through repressing ERa signaling

Background: The sex steroid estrogen plays a major role in the development and progression of breast cancer. Estrogen promotes breast cancer proliferation through a number of established pathways. CDK11p58, a Ser/Thr kinase which belongs to Cell Division Cycle 2-like 1 (CDC2L1) subfamily, is associated with cell cycle progression, tumorigenesis and apoptotic signaling. In the previous study, we found that CDK11p58 interacted with estrogen receptor a (ERa) in breast tumor cells and repressed ERa transcriptional activity through promoting its ubiquitin/proteasome-mediated degradation. Here we sought to investigate the critical role of CDK11p58 in the carcinogenisis of breast cancer.

Methods and results: We measured the expression of CDK11p58 in 132 pairs of breast cancer tissues and adjacent tissues by IHC and qPCR. The mRNA and protein level of CDK11p58 were significant higher in breast cancer tissues than those in normal breast tissues. Interestingly, low expression of CDK11 was associated with lymph nodes metastasis in patients (P<0.05). Using the ERa + cell lines ZR-75-30 and T47D, we found CDK11p58 could repress the migration and invasion of ERa positive breast cancer cells. We further demonstrated that mRNA of integrinb3 were dramatically repressed by CDK11p58 by the TaqMan® Metastasis Gene Expression Assays. The effect was CDK11p58 kinase activity dependent. Expression of integrinβ3 was highly related with ERa signaling. While overexpression ERa stimulates integrinβ3 expression, knockdown of ERa attenuates integrinβ3 expression. By the Dual-luciferase array and CHIP assay, we found estrogen response elements (ERE) indeed existed in integrinβ3 promoter. ERa bound to the ERE on the integrinβ3 promoter and increased its transcription.

Conclusions: Our findings provide mechanistic insights into how CDK11p58 regulated the expression of integrinβ3 to inhibit the cell invasion though repressing the signaling of ERa in a kinase activity dependent way. These data indicate that CDK11p58 is an antimetastasis gene product in breast cancer and regulation of integrinβ3 by CDK11p58 through ERa could be part of a signaling pathway that determines and explains breast cancer invasion and metastasis.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-04-11.

Note: Characteristic beam parameter for the line electron gun

We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm(2) at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm(2)), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

Role of MUC20 overexpression as a predictor of recurrence and poor outcome in colorectal cancer

Background

Colorectal cancer (CRC) remains one of the most common cancers worldwide. We observed that MUC20 was significantly up-regulated in CRC patients with poor prognosis based on the microarray analysis. However, little is known about the role of MUC20 in CRC.

Methods

Microarray experiments were performed on the Affymetrix U133 plus 2.0 GeneChip Array. The protein and mRNA levels of MUC20 were examined by immunohistochemistry (IHC) and Real-Time quantitative PCR (RT-qPCR) in CRC tissues and adjacent noncancerous tissues (ANCT). ShRNA and overexpression plasmids were used to regulate MUC20 expression in CRC cell lines in vitro; wound healing, Transwell migration assays, and Western blotting were used to detect migration and invasion changes.

Results

MUC20 was one of the up-regulated genes in CRC patients with poor prognosis by microarray. Using IHC and RT-qPCR, we showed that MUC20 expression was significantly higher in CRC tissues than in ANCT (P < 0.05). We further showed that MUC20 overexpression was correlated with recurrence and poor outcome (P < 0.05). The Kaplan-Meier survival curves indicated that disease-free survival (DFS) and overall survival (OS) were significantly worse in CRC patients with MUC20 overexpression. The Cox multivariate analysis revealed that MUC20 overexpression and TNM stage were independent prognostic factors. Elevated expression of MUC20 in cells promoted migration and invasion, whereas ShRNA-mediated knockdown inhibited these processes. In addition, Western blotting demonstrated that MUC20-induced invasion was associated with MMP-2, MMP-3, and E-cadherin.

Conclusions

Cumulatively, MUC20 may serve as an important predictor of recurrence and poor outcome for CRC patients. MUC20 overexpression could enhance migration and invasion abilities of CRC cells. Translation of its roles into clinical practice will need further investigation and additional test validation.

Identification of chromosomal copy number variations and novel candidate loci in hereditary nonpolyposis colorectal cancer with mismatch repair proficiency

The pathogenesis of microsatellite stable hereditary non-polyposis colorectal cancers (MSS HNPCC) is unclear. To identify genomic regions that might be involved in MSS HNPCC pathogenesis, we selected 20 pairs of MSS HNPCC for a genome-wide study using copy number variation targeted (CNV-targeted) CytoScan HD Array. A remarkably increased frequency of 20q gain (70%) and high levels of copy-neutral loss of heterozygosity (40%) were observed. The most frequent tumor-specific CNVs included amplifications (7p21.3-15.1, 8q13.3-24.3, 13q14.1-33.3 and 20q12-13.33) and deletions (8p11.23-23.1, 15q11.2-26.1, 17p13.1-13.3 and 18q11.2-21.33). In addition, 10 novel CNVs were discovered and led to identification of WDR16 and RAPGEF5 as candidate genes involved in tumorigenesis, displaying a robust correlation between expression and genomic alterations. Moreover, WDR16 and RAPGEF5 exhibited altered protein expression levels as assessed by immunohistochemistry (IHC) in 41 other independent samples. Finally, high consistencies (68-84%) were observed between CNVs by Array and quantitative PCR. These findings are important for further elucidating MSS HNPCC pathogenesis.

Abnormal expression of GADD45B in human colorectal carcinoma

Background

GADD45B is a member of the growth arrest DNA damage-inducible gene family associated with cell growth control, apoptosis, and DNA damage repair response. The aim of this study is to detect the role of GADD45B in colorectal carcinoma (CRC); the area not studied in depth to date.

Methods

The mRNA and protein levels of GADD45B were examined by Real-Time quantitative PCR (RT-qPCR) and immunohistochemistry (IHC) in CRC tissues and adjacent noncancerous tissues (ANCT). Over-expression plasmids and SiRNA were used to regulate GADD45B expression in CRC cell lines in vitro and flow cytometry and Western blotting were used to detect apoptotic changes.

Results

The mRNA and protein levels of GADD45B were significantly higher in CRC tissues than those in ANCT (P<0.05). Up-regulation of GADD45B was also correlated with relapse and death of CRC patients (P<0.05). The Kaplan-Meier survival curves indicated that disease-free survival (DFS) was significantly worse in CRC patients who showed GADD45B overexpression. A Cox multivariate analysis revealed that GADD45B overexpression and TNM stage were significant factors affecting patients’ survival. On the other hand, as a tumor suppressor gene, GADD45B amplified from normal colorectal tissues could induce apoptosis in CRC cell lines and may be associated with the p53-mediated apoptotic pathways.

Conclusion

GADD45B, a tumor suppressor gene potentially through the p53-mediated apoptotic pathways, is paradoxically overexpressed in CRC and as such may play an unappreciated role in tumorigenesis. The exact mechanism of GADD45B inactivation and overexpression requires further investigation. GADD45B could be a potential therapeutic target for CRC treatment in future.

Asymmetric dimethylarginine and carotid atherosclerosis in Type 2 diabetes mellitus

BACKGROUND

Circulating asymmetric dimethylarginine (ADMA) concentration is elevated in patients with Type 2 diabetes mellitus (T2DM).

AIM

To assess the relationship between plasma ADMA concentration and carotid atherosclerosis in patients with T2DM.

SUBJECTS AND METHODS

A total of 72 newly diagnosed and untreated T2DM individuals and 72 healthy controls were studied. Carotid atherosclerosis was determined by ultrasonographically evaluated intima- media thickness (IMT) and plaque score. Plasma concentration of ADMA was measured by high-performance liquid chromatography.

RESULTS

Plasma ADMA, mean IMT, and plaque score were higher in diabetic patients compared with controls. Univariate and multivariate analyses demonstrated an independent association between ADMA and mean IMT in diabetic patients. On a multiple logistic regression analysis, ADMA was the sole predictor of carotid plaque formation (plaque score ≥1.1) (odds ratio 2.43, 95% confidence interval 1.19 to 4.94, p<0.05).

CONCLUSION

Our results suggest that increased levels of ADMA might be involved in the development of carotid atherosclerosis in T2DM.

Cordycepin as a sensitizer to tumour necrosis factor (TNF)-α-induced apoptosis through eukaryotic translation initiation factor 2α (eIF2α)- and mammalian target of rapamycin complex 1 (mTORC1)-mediated inhibition of nuclear factor (NF)-κB

Cordycepin (3'-deoxyadenosine) is one of the major bioactive substances produced by Cordyceps militaris, a traditional medicinal mushroom. Cordycepin possesses several biological activities, including both pro-apoptotic and anti-apoptotic properties. In the present report, we investigated an effect of cordycepin on the survival of cells exposed to tumour necrosis factor (TNF)-α. We found that subtoxic doses of cordycepin increased susceptibility of cells to TNF-α-induced apoptosis. It was associated with suppression of nuclear factor-κB (NF-κB), a major prosurvival component involved in TNF-α signalling. The adenosine transporter and A₃ adenosine receptor, but not A₁ and A₂ adenosine receptors, mediated both anti-NF-κB and pro-apoptotic effects. We found that cordycepin had the potential to phosphorylate eukaryotic translation initiation factor 2α (eIF2α) and that activation of eIF2α mimicked the suppressive effect of cordycepin on the NF-κB pathway. Furthermore, activation of eIF2α sensitized cells to TNF-α-induced apoptosis. To identify molecular events downstream of eIF2α, the role of mammalian target of rapamycin complex 1 (mTORC1) was examined. Selective activation of ₃eIF2α, as well as treatment with cordycepin, caused phosphorylation of mTORC1. Rapamycin, an inhibitor of mTORC1, significantly reversed the suppressive effects of eIF2α on NF-κB. These results suggest that cordycepin sensitizes cells to TNF-α-induced apoptosis, at least in part, via induction of the eIF2α-mTORC1 pathway and consequent suppression of NF-κB.

A pilot study to evaluate assisted freehand ultrasound elasticity imaging in the sizing of early breast cancer: a comparison of B-mode and AFUSON elasticity ultrasound with histopathology measurements

OBJECTIVE

This pilot study investigates the role of assisted-freehand ultrasound (AFUSON) elasticity imaging of the breast in assessing the contour, size and area of 23 early breast cancers by making comparison of AFUSON with the equivalent B-mode ultrasound images and gold standard histopathology slides.

METHODS

The B-mode, AFUSON and digitised histopathology slides of three early breast cancers were compared for contour, size and area with histopathology scans. AFUSON features that corresponded to areas of known malignant change on the histopathology slides were regarded as diagnostic. These diagnostic criteria were then applied to the B-mode and AFUSON elasticity images of all 23 breast cancers in the pilot study without having the availability of the histopathology scans for reference. Corresponding diameters were measured and the results were compared with the equivalent measurements on the scans of the histology slides. The results were tabulated in histogram form. Diagnostic confidence levels were evaluated.

RESULTS

Size dimension accuracy increased from 66% using B-mode alone to 82% using combined B-mode and AFUSON elasticity images. Tumour area accuracy was also increased. A small number of cases had a striking visual similarity of shape on AFUSON elasticity scans and histopathology slides.

CONCLUSION

In spite of the shortfalls in this study, AFUSON elasticity imaging was capable of acquiring some high-quality images that showed strong correlation between AFUSON elasticity and scans of histology slides. Further studies will be carried out to refine the technique and determine if it has a role in the diagnosis and management of breast cancer.