63 Effect of 100-km ultramarathon on N-terminal pro-B-type natriuretic peptide variation

Introduction

The change in N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels follows strenuous endurance exercise-imposed paradox. Our previous reports showed significant body weight (BW) loss with dehydration was common in ultramarathon runners. The aim of this study is to investigate whether the dehydration and renin-angiotensin-aldosterone system activation possibly contribute to exercise-induced NT-proBNP release.

Methods

Twenty-six participants who finished a 100-km ultramarathon in Taiwan were enrolled. For each participant, blood samples and spot urine samples were collected one week before the race, as well as immediately and 24 hours after the finish. Body weight change was recorded to monitor the hydration status.

Results

Prolonged endurance exercise led to a substantial increase in NT-pro-BNP. Compared to pre-race values, NT-pro-BNP levels significantly increased immediately after the race (24.3 ± 20.2 to 402.9 ± 305.9 pg/mL, p < 0.05) and maintained the lasting high levels till 24 hours after the race finished (143.7 ± 126.1 pg/mL, p < 0.05). The fractional excretion of sodium values were all below 1% in three different time points. The 100-km ultramarathon resulted in significant BW loss, and elevated of renin and aldosterone levels. However, only 24 hours after the race, there was a positive significantly relationship between NT-proBNP and aldosterone levels, but negative significantly relationship between NT-proBNP and BW increase during the recovery phase.

Conclusions

Results of this study showed the mechanism of NT-proBNP release immediate following the race were multifaceted. However, during the recovery phase, rehydration might lead to the decrease of NT-proBNP in the volume depletion state.

Chromosomal instability as a prognostic marker in cervical cancer

Background

Cervical cancer is the third most common cancer in women globally, and despite treatment, distant metastasis and nodal recurrence will still develop in approximately 30% of patients. The ability to predict which patients are likely to experience distant relapse would allow clinicians to better tailor treatment. Previous studies have investigated the role of chromosomal instability (CIN) in cancer, which can promote tumour initiation and growth; a hallmark of human malignancies. In this study, we sought to examine the published CIN70 gene signature in a cohort of cervical cancer patients treated at the Princess Margaret (PM) Cancer Centre and an independent cohort of The Cancer Genome Atlas (TCGA) cervical cancer patients, to determine if this CIN signature associated with patient outcome.

Methods

Cervical cancer samples were collected from 79 patients, treated between 2000–2007 at the PM, prior to undergoing curative chemo-radiation. Total RNA was extracted from each patient sample and analyzed using the GeneChip Human Genome U133 Plus 2.0 array (Affymetrix).

Results

High CIN70 scores were significantly related to increased chromosomal alterations in TCGA cervical cancer patients, including a higher percentage of genome altered and a higher number of copy number alterations. In addition, this same CIN70 signature was shown to be predictive of para-aortic nodal relapse in the PM Cancer Centre cohort.

Conclusions

These findings demonstrate that chromosomal instability plays an important role in cervical cancer, and is significantly associated with patient outcome. For the first time, this CIN70 gene signature provided prognostic value for patients with cervical cancer.

Developing a prognostic micro-RNA signature for human cervical carcinoma

Cervical cancer remains the third most frequently diagnosed and fourth leading cause of cancer death in women worldwide. We sought to develop a micro-RNA signature that was prognostic for disease-free survival, which could potentially allow tailoring of treatment for cervical cancer patients. A candidate prognostic 9-micro-RNA signature set was identified in the training set of 79 frozen specimens. However, three different approaches to validate this signature in an independent cohort of 87 patients with formalin-fixed paraffin-embedded (FFPE) specimens, were unsuccessful. There are several challenges and considerations associated with developing a prognostic micro-RNA signature for cervical cancer, namely: tumour heterogeneity, lack of concordance between frozen and FFPE specimens, and platform selection for global micro-RNA expression profiling in this disease. Our observations provide an important cautionary tale for future miRNA signature studies for cervical cancer, which can also be potentially applicable to miRNA profiling studies involving other types of human malignancies.

Abstract 4372: MiR-449a promotes breast cancer progression by activating the NF-κB pathway

INTRODUCTION

MicroRNAs (miRs) have been implicated in various human malignancies and are being developed as diagnostic, predictive, and prognostic biomarkers. Our previous global profiling studies found miR-449a to be over-expressed in archival lymph node-negative invasive ductal breast carcinoma samples (n=74) when compared to normal tissues. Furthermore, miR-449a expression level was significantly associated with relapse. The mechanism(s) by which miR-449a functions remains unknown, and the aim of the current study was therefore to elucidate the roles and mRNA targets of miR-449a in breast cancer.

MATERIAL AND METHODS

MiR-449a expression was evaluated in six human breast cancer cell lines (T47D, MDA-MB-468, MDA-MB-231, MCF-7, MDA-MB-453, and ZR75-1). Three of these cell lines, T47D, MMDA-MB-468, and MDA-MB-231, were selected and used to assess the biological effects of miR-449a on cell viability, clonogenicity, cell migration, and invasion. Downstream target genes were identified by combining in silico miRWalk prediction and cell line/patient sample microarray data. Targets were validated using qRT-PCR and luciferase reporter assays.

RESULTS

Consistent with our global profiling work, several (4/6) of the tested breast cancer cell lines over-expressed miR-449a. CDC20B, the miR-449a host gene and an essential regulator of cell division, was also over-expressed. Knockdown of miR-449a resulted in significantly decreased cell viability, clonogenic survival, migration, and invasion. MiR-449a candidate targets were then identified by integrating in silico prediction algorithms, cell line mRNA expression profiling (Affymetrix Human Genome U133 Plus 2.0), and clinical specimen mRNA expression data. Two genes, CRIP2 (Cysteine rich protein 2, a transcription factor) and PRKAG1 (Protein Kinase, AMP-Activated, Gamma 1 Non-Catalytic), were verified as miR-449a targets using qRT-PCR. Moreover, direct interactions between miR-449a and the 3′-UTRs of both CRIP2 and PRKAG1 were confirmed using luciferase reporter assays. Inhibition of CRIP2 by miR-449a allowed for NF-κB-induced transcription of survival, proliferation, and growth-related genes, providing further evidence for the role of miR-449a in breast cancer progression.

CONCLUSIONS

MiR-449a is over-expressed in breast cancer cells, promoting cellular proliferation, migration, and invasion. One mechanism by which miR-449a functions is to down-regulate CRIP2, leading to NF-kB activation and possible cancer progression. Further investigations into gene regulation by miR-449a may reveal other promising targets for the management of breast cancer.

Citation Format: Wei Shi, Matthew Lee, Ryunosuke Kogo, Jeff Bruce, Christine How, Kenneth W. Yip, Fei-Fei Liu. MiR-449a promotes breast cancer progression by activating the NF-κB pathway. [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 4372. doi:10.1158/1538-7445.AM2014-4372

Abstract 4369: The microRNA-218-survivin axis regulates cervical cancer cell migration and invasion

MicroRNA (miR)-218 down-regulation has been reported in numerous human malignancies. In cervical cancer, we identified that lower miR-218 expression was significantly associated with poorer overall survival, disease-free survival, and pelvic/para-aortic lymph node recurrence. Further analyses of cervical cancer data from The Cancer Genome Atlas (TCGA) identified that this down-regulation was associated with a genomic locus loss (hsa-mir-218-1:4p15.31, hsa-mir-218-2:5q34, n=105). The objective of the current study was to elucidate the cellular and molecular functions of miR-218. MiR-218 transfection into cervical cancer cells (SiHa and ME-180) significantly reduced cell migration (by 66% and 89%, respectively), invasion (by 49% and 67%, respectively), and clonogenic capacity (by 42% and 53%, respectively), relative to control-transfected cells (P<0.05). In order to identify clinically relevant miR-218 target genes, we used an integrated trimodal approach, incorporating DNA microarray (Affymetrix Human Genome U133 Plus 2.0) analyses of 79 clinical samples, miR-218 transfection, and miRDB target prediction. The most significant target was survivin (BIRC5); miR-218 transfection confirmed a reduction in survivin mRNA and protein expression in both SiHa and ME-180 cells. Furthermore, a direct interaction between the survivin-3′UTR and miR-218 was validated using a luciferase reporter assay. siRNA knockdown of survivin in SiHa and ME-180 significantly reduced cell migration (by 76% and 83%, respectively), invasion (by 79% and 88%, respectively), and clonogenic capacity (by 98% and 97%, respectively), relative to control cells (P<0.05). YM155, a small-molecule survivin suppressant, effectively reduced survivin mRNA and protein levels in a concentration- and time-dependent manner. This compound correspondingly decreased cervical cancer cell proliferation and clonogenic survival. Our results suggest that the miR-218-survivin axis plays an important role in cervical cancer progression.

Citation Format: Ryunosuke Kogo, Christine How, Jeff Bruce, Willa Shi, Kenneth W. Yip, Laurie Ailles, Fei-Fei Liu. The microRNA-218-survivin axis regulates cervical cancer cell migration and invasion. [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 4369. doi:10.1158/1538-7445.AM2014-4369

Hotspot activating PRKD1 somatic mutations in polymorphous low-grade adenocarcinomas of the salivary glands

Polymorphous low-grade adenocarcinoma (PLGA) is the second most frequent type of malignant tumor of the minor salivary glands. We identified PRKD1 hotspot mutations encoding p.Glu710Asp in 72.9% of PLGAs but not in other salivary gland tumors. Functional studies demonstrated that this kinase-activating alteration likely constitutes a driver of PLGA.

Novel PRKD gene rearrangements and variant fusions in cribriform adenocarcinoma of salivary gland origin

Polymorphous low-grade adenocarcinoma (PLGA) and cribriform adenocarcinoma of minor salivary gland (CAMSG) are low-grade carcinomas arising most often in oral cavity and oropharynx, respectively. Controversy exists as to whether these tumors represent separate entities or variants of one spectrum, as they appear to have significant overlap, but also clinicopathologic differences. As many salivary carcinomas harbor recurrent translocations, paired-end RNA sequencing and FusionSeq data analysis was applied for novel fusion discovery on two CAMSGs and two PLGAs. Validated rearrangements were then screened by fluorescence in situ hybridization (FISH) in 60 cases. Histologic classification was performed without knowledge of fusion status and included: 21 CAMSG, 18 classic PLGA, and 21 with "mixed/indeterminate" features. The RNAseq of 2 CAMSGs showed ARID1A-PRKD1 and DDX3X-PRKD1 fusions, respectively, while no fusion candidates were identified in two PLGAs. FISH for PRKD1 rearrangements identified 11 additional cases (22%), two more showing ARID1A-PRKD1 fusions. As PRKD2 and PRKD3 share similar functions with PRKD1 in the diacylglycerol and protein kinase C signal transduction pathway, we expanded the investigation for these genes by FISH. Six additional cases each showed PRKD2 and PRKD3 rearrangements. Of the 26 (43%) fusion-positive tumors, there were 16 (80%) CAMSGs and 9 (45%) indeterminate cases. A PRKD2 rearrangement was detected in one PLGA (6%). We describe novel and recurrent gene rearrangements in PRKD1-3 primarily in CAMSG, suggesting a possible pathogenetic dichotomy from "classic" PLGA. However, the presence of similar genetic findings in half of the indeterminate cases and a single PLGA suggests a possible shared pathogenesis for these tumor types.

MicroRNA-196b regulates the homeobox B7-vascular endothelial growth factor axis in cervical cancer

The down-regulation of microRNA-196b (miR-196b) has been reported, but its contribution to cervical cancer progression remains to be investigated. In this study, we first demonstrated that miR-196b down-regulation was significantly associated with worse disease-free survival (DFS) for cervical cancer patients treated with combined chemo-radiation. Secondly, using a tri-modal approach for target identification, we determined that homeobox-B7 (HOXB7) was a bona fide target for miR-196b, and in turn, vascular endothelial growth factor (VEGF) was a downstream transcript regulated by HOXB7. Reconstitution of miR-196b expression by transient transfection resulted in reduced cell growth, clonogenicity, migration and invasion in vitro, as well as reduced tumor angiogenesis and tumor cell proliferation in vivo. Concordantly, siRNA knockdown of HOXB7 or VEGF phenocopied the biological effects of miR-196b over-expression. Our findings have demonstrated that the miR-196b/HOXB7/VEGF pathway plays an important role in cervical cancer progression; hence targeting this pathway could be a promising therapeutic strategy for the future management of this disease.

Excellence in Radiation Research for the 21st Century (EIRR21): description of an innovative research training program

PURPOSE

To describe and assess an interdisciplinary research training program for graduate students, postdoctoral fellows, and clinical fellows focused on radiation medicine; funded by the Canadian Institutes for Health Research since 2003, the program entitled "Excellence in Radiation Research for the 21st Century" (EIRR21) aims to train the next generation of interdisciplinary radiation medicine researchers.

METHODS AND MATERIALS

Online surveys evaluating EIRR21 were sent to trainees (n=56), mentors (n=36), and seminar speakers (n=72). Face-to-face interviews were also conducted for trainee liaisons (n=4) and participants in the international exchange program (n=2).

RESULTS

Overall response rates ranged from 53% (mentors) to 91% (trainees). EIRR21 was well received by trainees, with the acquisition of several important skills related to their research endeavors. An innovative seminar series, entitled Brainstorm sessions, imparting "extracurricular" knowledge in intellectual property protection, commercialization strategies, and effective communication, was considered to be the most valuable component of the program. Networking with researchers in other disciplines was also facilitated owing to program participation.

CONCLUSIONS

EIRR21 is an innovative training program that positively impacts the biomedical community and imparts valuable skill sets to foster success for the future generation of radiation medicine researchers.

Abstract 2311: microRNA-196b regulates HOXB7 in cervical cancer

Introduction: microRNAs (miRNAs) have been shown to play an important biological role in many human malignancies. The down-regulation of miR-196b has been previously reported in cervical cancer (CaCx), but its contribution to tumor progression remains unelucidated. Materials and Methods: miRNA expression was measured in frozen tissues from CaCx biopsies (n=79) and normal cervix (n=11), plus three CaCx cell lines (ME-180, SiHa and HT-3) using a quantitative real-time PCR (qPCR) approach simultaneously measuring 377 miRNAs. SiHa and ME-180 cells were transfected with 30 nmol/L of pre-miR-196b, pre-miR Negative Control (NC), siHOXB7, siVEGF, or Negative Control siRNA. Cell viability, clonogenicity and migration/invasion were analyzed using the Trypan blue exclusion assay, clonogenic assay and trans-well migration assays, respectively. Protein levels of HOXB7 and VEGF were measured by immunoblotting and ELISA, respectively. To determine candidate mRNA targets of miR-196b, a tri-modal approach was utilized by combining: a) all predicted targets from five target prediction databases; b) genes upregulated in CaCx patients; and c) genes down-regulated after in vitro miR-196b over-expression. A luciferase reporter assay was used to confirm the binding of miR-196b to the HOXB7 3′ UTR. Tumor formation was monitored in xenograft tumors in SCID mice; CD31 and Ki67 immunostaining were performed on tumors 25 days after implantation. Results: Significant down-regulation of miR-196b was observed in the CaCx cells lines and tissues. Patients with low miR-196b expression (n=39) experienced worse disease-free survival compared to those with high (n=39) miR-196b expression (p=0.02, HR=0.39). Pre-miR-196b transfection reduced cell viability (25% after 48h; 41% after 72h), clonogenicity (57%) and invasion (32% vs. 63% for cells treated with NC). In vivo, pre-miR-196b slightly decreased tumor growth, but associated with significantly reduced CD31 (69%) and Ki-67 expression (46% vs. 53% for NC cells). The luciferase reporter assay verified that HOXB7 is a direct and specific target of miR-196b. Decreased VEGF mRNA (43%) and protein (78%) levels after HOXB7 knockdown demonstrated that VEGF was a downstream mediator of HOXB7 activation. siRNA knockdown of HOXB7 or VEGF recapitulated the biological effects of miR-196b over-expression, including reduced cell viability (66% for siHOXB7 at 72h; 60% for VEGF at 72h), clonogenicity (69% for siHOXB7; 78% for siVEGF) and invasion (52% for siHOXB7 and 42% for siVEGF vs. 74% for Negative Control cells); thus corroborating the miR-196b/HOXB7/VEGF axis in CaCx progression. Conclusion: We have newly identified the miR-196b/HOXB7/VEGF pathway as an important dysregulated axis contributing to human CaCx progression; hence therapeutic targeting of this pathway could potentially improve patient outcome.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2311. doi:1538-7445.AM2012-2311

Micro-RNAs as diagnostic or prognostic markers in human epithelial malignancies

Micro-RNAs (miRs) are important regulators of mRNA and protein expression; the ability of miR expression profilings to distinguish different cancer types and classify their sub-types has been well-described. They also represent a novel biological entity with potential value as tumour biomarkers, which can improve diagnosis, prognosis, and monitoring of treatment response for human cancers. This endeavour has been greatly facilitated by the stability of miRs in formalin-fixed paraffin-embedded (FFPE) tissues, and their detection in circulation. This review will summarize some of the key dysregulated miRs described to date in human epithelial malignancies, and their potential value as molecular bio-markers in FFPE tissues and blood samples. There remain many challenges in this domain, however, with the evolution of different platforms, the complexities of normalizing miR profiling data, and the importance of evaluating sufficiently-powered training and validation cohorts. Nonetheless, well-conducted miR profiling studies should contribute important insights into the molecular aberrations driving human cancer development and progression.

Abstract 2023: Potential importance of micro-RNA-193b in human head and neck squamous cell carcinoma

INTRODUCTION

Head and neck squamous cell carcinoma (HNSCC) is the fifth most common cancer worldwide, half of these patients presenting with locally advanced disease, which despite aggressive multi-modality treatments, achieves five-year survival rates of only 50%, underscoring a need to better understand the biological bases of this disease. One approach would be examining HNSCC through the lens of micro-RNAs (miRs), which are endogenous non-coding RNAs that could post-transcriptionally regulate up to 1/3 of all human genes.

EXPERIMENTAL DESIGN

Global miR profilings were conducted on 54 primary human HNSCC samples, and three HNSCC cell lines (FaDu, UTSCC42a, UTSCC8), compared to normal laryngeal tissues, and a normal oral epithelial cell line, using the Taqman Low-Density Array (Applied Biosystems). The most deregulated miRs were then selected for further evaluation by knocking down the over-expressed miRs using LNAs (locked nucleic acids), and cellular effects were then determined using MTS, clonogenic, and flow cytometry assays. Micro-RNA-193b was selected for more detailed examination; mRNA candidate targets were determined by combining three different approaches described below. Binding of miR-193b with candidate mRNA was determined using a luciferase assay after co-transfection of a luciferase vector containing the 3′UTR of the mRNA target, with LNA miR-193b.

RESULTS

Based on the predictive power (relapse vs. non-relapse) from the clinical samples, and biological relevance in cell line studies (tumour vs. normal), six top dysregulated (over-expressed) miRs; miR-15b, miR-106b, miR-130a, miR-193b, miR-205, and miR-423, were selected for further evaluation. Only miR-106b, miR-193b and miR-205 were able to reduce cell proliferation in all three cell lines after LNA, assessed using both the MTS and clonogenic assays, with miR-193b also increasing the proportion of cells in the sub-G1 phase of the cell cycle. Candidate mRNA targets of miR-193b were elucidated by integrating in silico prediction algorithms with in vitro experimental mRNA expression profilings, and publically-available clinical mRNA expression data. A set of 11 potential mRNA targets of miR-193b were selected; 6 of which were over-expressed after miR-193b LNA knockdown. One target, Neurofibromatosis 1 (NF1), was demonstrated to directly interact with miR-193b using the luciferase vector carrying the 3′UTR of NF1.

CONCLUSION

Global miR profiling of HNSCC tissues and cell lines, demonstrated a trend toward over-expressed miRs. MiR-193b appears to be an important over-expressed miR in HNSCC, which targets NF1, a RAS-GTPase which hydrolyzes active RAS-GTP into inactive RAS-GDP. This failure to inactivate RAS might therefore be a potential mechanism by which several downstream oncogenic pathways of MAPK, STAT, and PI(3)K are activated, signaling continued cellular proliferation, and anti-apoptosis, hallmarks of aggressive HNSCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2023.

High level production of the Magnaporthe grisea fructose 1,6-bisphosphate aldolase enzyme in Escherichia coli using a small volume bench-top fermentor

The Class II fructose 1,6-bisphosphate aldolase from the Rice Blast causative agent Magnaporthe grisea was subcloned in the Escherichia coli vector pT7-7. The enzyme was overexpressed using fed-batch fermentation in a small bench-top reactor. A total of 275 g of cells and 1.3 g of highly purified enzyme with a specific activity of 70 U/mg were obtained from a 1.5L culture. The purified enzyme is a homodimer of 39.6 kDa subunits with a zinc ion at the active site. Kinetic characterization indicates that the enzyme has a K(m) of 51 microM, a k(cat) of 46 s(-1), and a pH optimum of 7.8 for fructose 1,6-bisphosphate cleavage. The fermentation system procedure reported exemplifies the potential of using a lab-scale bioreactor for the large scale production of recombinant enzymes.