Three novel alternative splicing mutations in BCR-ABL1 detected in CML patients with resistance to kinase inhibitors

INTRODUCTION

Multiple types of mutations in the BCR-ABL1 kinase domain have been reported. We previously reported a common alternatively spliced BCR-ABL mRNA with a 35-nucleotide insertion (35INS). We report three novel alternative splicing mutants expressed as the dominant transcripts in patient with chronic myelogenous leukemia and resistance to kinase inhibitors.

METHODS

We screened RNA from more than 200 patients with resistance to more than one of the three kinase inhibitors for ABL1 kinase domain mutations by direct sequencing.

RESULTS

We found three not previously described splice mutants. All three showed >90% mutant transcript. The first resulted from the insertion of 79 nucleotides into the ABL1 exon 8-9 junction. The inserted sequence contained a sequence from regions of intron 8, located 120 bp apart: the 35-nucleotide sequence previously described, and an additional 44-nucleotide segment downstream from 35INS. The combined 79-nucleotide insertion splice mutant showed the same protein change as 35INS (p C475YfsX11). The second splice mutation comprised an 84-nucleotide sequence from intron 7 inserted into the ABL1 exon7-8 junction, also causing a frameshift and protein truncation (p A424EfsX18). The third splice derived from a 231-nucleotide sequence from intron 4 retained in the ABL1 exon 4-5 junction adding 40 intron-encoded amino acids and leading to a frameshift and early termination (p E275LfsX41).

CONCLUSION

These findings, when combined with the data on 35INS, support the concept that loss of the C-terminus of BCR-ABL1 is associated with significant resistance to kinase inhibitors; this mechanism appears to be a major source of resistance to kinase inhibitors.

Application of a magnetic dipole modelling approach to the problem of tracking a capsule endoscope

This paper shows that a small cylindrical permanent magnet enclosed inside a capsule can be used as a marker in endoscopy procedures. A modelling approach that treats the magnetic marker as a magnetic dipole is presented and an efficient, non-invasive, and low-cost localization method to track the capsule is proposed. A sensor array consisting of 16 magneto-resistive sensors is used to measure the magnetic field at multiple predetermined positions. The position and orientation parameters of the marker are calculated by minimizing the error between calculated and measured values of the field. The Levenberg-Marquardt optimization method is used to solve the inverse magnetic problem. Results are presented that show that the method is accurate and can be used for real-time tracking. The technique is applicable in environments that do not contain ferromagnetic materials as is the case for the human body.

Association between short sleep duration and the risk of sensitization to food and aero allergens in rural Chinese adolescents

BACKGROUND

Both long and short sleep duration have been associated with obesity, cardiovascular disease, and diabetes. However, there have been no previous studies investigating the potential relationship between altered sleep duration and allergen sensitization.

OBJECTIVE

To explore the association between sleep duration and sensitization to food and aeroallergens.

METHODS

This study includes 1534 rural Chinese adolescent twins aged 12-21 years who completed standard sleep questionnaires and skin prick tests (SPTs) to nine food and five aeroallergens. Total sleep time was defined as the interval from bedtime to wake-up time minus sleep latency. Sensitization was defined as having at least one positive SPT.

RESULTS

Compared with individuals with the highest (third) tertile of sleep duration, those who slept less were more likely to be sensitized to any food allergen with odds ratios (ORs) of 1.9 [95% confidence interval (CI): 1.3-2.7] and 1.4 (95% CI: 1.0-1.9) for the first and second tertiles (trend test P(trend)=3×10(-4)), respectively. The corresponding ORs for sensitization to any aeroallergen were 1.5 (95% CI: 1.1-2.0) and 1.3 (95% CI: 1.0-1.7) (P(trend)=8×10(-3)). These associations were independent of percent body fat. In addition, we observed a significant dose-response association between the number of positive SPTs and percentage of shortest sleep duration (first tertile) (P(trend)=1×10(-3)).

CONCLUSIONS AND CLINICAL RELEVANCE

In this sample of relatively lean rural Chinese adolescents, we found that short sleep duration was associated with increasing risk of sensitization to food and aeroallergens, independent of percent body fat. Longitudinal studies are needed to further determine the temporal and causal relationships. If short sleep duration indeed is one of the risk factors for allergic sensitization, the global burden of allergic diseases could be dramatically reduced by providing appropriate guidance on sleep duration for youth.

Search for stopped Gluinos in pp collisions at square root s=7 TeV

The results of the first search for long-lived gluinos produced in 7 TeV pp collisions at the CERN Large Hadron Collider are presented. The search looks for evidence of long-lived particles that stop in the CMS detector and decay in the quiescent periods between beam crossings. In a dataset with a peak instantaneous luminosity of 1×10(32) cm-2 s-1, an integrated luminosity of 10 pb-1, and a search interval corresponding to 62 hours of LHC operation, no significant excess above background was observed. Limits at the 95% confidence level on gluino pair production over 13 orders of magnitude of gluino lifetime are set. For a mass difference mg - mχ1(0) >100 GeV/c2, and assuming BR(g→gχ1(0))=100%, mg < 370 GeV/c2 are excluded for lifetimes from 10 μs to 1000 s.

Acceptance of a vaccine against pandemic influenza A (H1N1) virus amongst healthcare workers in Beijing, China

Due to the advent of the new influenza A (H1N1) strain in 2009, many countries introduced mass immunization programs. Healthcare workers (HCWs) were amongst the key groups targeted for the vaccine in these programs. However, experience with the seasonal influenza vaccine has shown that there are multiple barriers related to the attitudes and perceptions of the population which influence uptake. The aim of this study was to determine pandemic influenza A (H1N1) vaccination rate amongst a group of Chinese HCWs and the associated factors around acceptance. A cross-sectional investigation of HCWs (doctors, nurses and technicians) from 19 hospitals in Beijing, China was conducted in January 2010. The main outcome measures were awareness, risk perception of H1N1, preventive measures and uptake of H1N1 vaccination during the pandemic. A total of 1657 HCWs completed the survey. A quarter of the participants reported receiving the pandemic influenza A (H1N1) vaccine. Occupation (being a doctor), receiving seasonal flu vaccine and believing in the effectiveness of the vaccine were all strongly associated with accepting the pandemic influenza A (H1N1) vaccine. Over a thousand participants (61%, 1008/1657) agreed that they were 'concerned about the side effects of the swine flu vaccine', while 758 (46%) were 'concerned that the vaccine had not been tested adequately'. While studies reported high rates of willingness to receive the vaccine, in reality these did not transpire. Aside from promoting seasonal flu vaccination, authorities need to start educational campaigns much earlier in a pandemic. Programs that are simultaneously launched with the introduction of the vaccine will not be as successful, as those which have built momentum alongside the pandemic.

Pharmacokinetics of lipoyl vildagliptin, a novel dipeptidyl peptidase IV inhibitor after oral administration in rats

The pharmacokinetics of lipoyl vildagliptin, a novel dipeptidyl peptidase IV (DPP IV) inhibitor, was studied in rats after oral administration for developing it as an antidiabetic agent. A liquid chromatography-tandem mass spectroscopy (LC-MS/MS) method was developed to determine lipoyl vildagliptin in rat plasma. After an overnight fasting, rats were orally given lipoyl vildagliptin. Following a single oral dose of 25, 50, and 100 mg x kg(-1), T(max) values were from 1.25 to 1.84 h, CL/F values were around 100 l h(-1) kg(-1). In the dose range, C(max) values (63.9-296 μg x l(-1)) and AUC(0-∞)values (260-1214 μg x h x l(-1)) were proportional to the doses. In conclusion, this LC-MS/MS method for the determination of lipoyl vildagliptin in rat plasma was selective and sensitive. In rats, lipoyl vildagliptin displayed linear pharmacokinetics after a single oral dose in the range of 25-100 mg x kg(-1). Lipoyl vildagliptin might have very high CL/F values and V(d)/F values, which indicated that the bioavailability of this drug might be low or lipoyl vildagliptin might distribute extensively or accumulate in tissues in view of its high liposolubility.

195 SPERMATOZOAL PROTEIN MARKERS FOR ANGUS BULL FERTILITY

Fertility is one of the most economically important traits controlling animal reproduction. Despite its significant economic impact, there are no reliable markers to predict semen quality. The objective of this study was to identify spermatozoal proteins associated with bull fertility, the ability of the sperm to fertilize the oocyte and support embryonic development. To accomplish our objectives, we isolated total spermatozoal proteins from 4 Angus bulls with different fertility phenotypes. Next, differentially expressed proteins were determined using two-dimensional differential in-gel electrophoresis (2D-DIGE), followed by sequencing of the most differentially expressed proteins. Immunoblotting experiments were conducted to confirm expression of key proteins detected by 2D-DIGE. Our results from 2D-DIGE experiments showed approximately 2000 detectable spermatozoal proteins. Of these comprehensive lists of proteins, we identified 80 of the proteins with the highest differential expression in spermatozoa from high- and low-fertility bulls. Diverse sets of differentially expressed proteins known to play roles in sperm motility, metabolism, and cell morphology were identified. These proteins included outer dense fibre of sperm tails 2 and manganous superoxide, heat shock protein, tubulins, α-enolase, and acrosomal vesicle protein-1. Expression profiles of outer dense fibre of sperm tails 2 and manganous superoxide dismutase were confirmed using immunoblotting. The findings are significant because they help us understand the fundamental biology of the male gamete and early development. In addition, the identified proteins can be used as molecular markers to predict bull fertility, an economically important trait. Funded in part by the Mississippi Agricultural and Forestry Experiment Station, American Angus Association, and Alta Genetics, Inc.

Effect of WT1 antisense mRNA on the induction of apoptosis in ovarian carcinoma SKOV3 cells

PURPOSE

To study the effect of WT1 antisense oligodeoxynucleotide (ASODN) transfection on the proliferation and apoptosis of SKOV3 cells.

METHODS

There were four groups in our study: normal control group, WT1 ASODN group, WT1 SODN group and lipofectamine group. Cell apoptosis was observed by flow cytometry. The effect of WT1 ASODN on cell proliferation was assayed by the MTT method. RT-PCR and Western blot were used to detect the expression level of WT1 mRNA and protein.

RESULTS

The growth of the ovarian cancer cell line SKOV3 became significantly slower and its activity was reduced after being transfected by WT1 ASODN, with the inhibition rate of 49.48%. WT1 antisense phosphorothioate oligonucleotides did not only inhibit cell proliferation, arrest cell cycle at G0-G1 checkpoint and induce apoptosis in SKOV3 ovarian carcinoma cells, but also downregulated WT1 mRNA and protein expression, which contributed to the apoptosis (p < 0.05).

CONCLUSION

WT1 antisense phosphorothioate oligonucleotides could both inhibit the proliferation and induce the apoptosis in SKOV3 ovarin carcinoma cell lines. Antisense oligonucleotides of WT1 may potentially help with the gene therapy of ovarian carcinoma.

L-malate production by metabolically engineered Escherichia coli

Escherichia coli strains (KJ060 and KJ073) that were previously developed for succinate production have now been modified for malate production. Many unexpected changes were observed during this investigation. The initial strategy of deleting fumarase isoenzymes was ineffective, and succinate continued to accumulate. Surprisingly, a mutation in fumarate reductase alone was sufficient to redirect carbon flow into malate even in the presence of fumarase. Further deletions were needed to inactivate malic enzymes (typically gluconeogenic) and prevent conversion to pyruvate. However, deletion of these genes (sfcA and maeB) resulted in the unexpected accumulation of D-lactate despite the prior deletion of mgsA and ldhA and the absence of apparent lactate dehydrogenase activity. Although the metabolic source of this D-lactate was not identified, lactate accumulation was increased by supplementation with pyruvate and decreased by the deletion of either pyruvate kinase gene (pykA or pykF) to reduce the supply of pyruvate. Many of the gene deletions adversely affected growth and cell yield in minimal medium under anaerobic conditions, and volumetric rates of malate production remained low. The final strain (XZ658) produced 163 mM malate, with a yield of 1.0 mol (mol glucose(-1)), half of the theoretical maximum. Using a two-stage process (aerobic cell growth and anaerobic malate production), this engineered strain produced 253 mM malate (34 g liter(-1)) within 72 h, with a higher yield (1.42 mol mol(-1)) and productivity (0.47 g liter(-1) h(-1)). This malate yield and productivity are equal to or better than those of other known biocatalysts.

Search for quark compositeness with the dijet centrality ratio in pp collisions at √s=7 TeV

A search for quark compositeness in the form of quark contact interactions, based on hadronic jet pairs (dijets) produced in proton-proton collisions at √s=7 TeV, is described. The data sample of the study corresponds to an integrated luminosity of 2.9 pb(-1) collected with the CMS detector at the LHC. The dijet centrality ratio, which quantifies the angular distribution of the dijets, is measured as a function of the invariant mass of the dijet system and is found to agree with the predictions of the standard model. A statistical analysis of the data provides a lower limit on the energy scale of quark contact interactions. The sensitivity of the analysis is such that the expected limit is 2.9 TeV; because the observed value of the centrality ratio at high invariant mass is below the expectation, the observed limit is 4.0 TeV at the 95% confidence level.

High strain rate testing of bovine trabecular bone

In spinal vertebral burst fractures, the dynamic properties of the trabecular centrum, which is the central region of porous bone inside the vertebra, can play an important role in determining the failure mode. If the failure occurs in the posterior portion of the vertebral body, spinal canal occlusion can occur and ejected trabecular bone can impact the spinal cord resulting in serious injury. About 15% of all spinal cord injuries are caused by such burst fractures. Unfortunately, due to the uniqueness of burst fracture injuries, postinjury investigation cannot always accurately assess the degree of damage caused by these fractures. This research makes an effort to begin understanding the governing effects in this important bone fracture event. Measurements of the dynamic deformation response of bovine trabecular bone with the marrow intact and marrow removed using a modified split-Hopkinson pressure bar apparatus are reported and compared with quasistatic deformation response results. Because trabecular bone is more compliant and lower in strength than cortical bone, typical Hopkinson pressure bar experimental techniques used for high strain rate testing of harder materials cannot be applied. Instead, a quartz-crystal-embedded, split-Hopkinson pressure bar developed for testing compliant, low strength materials is used. Care is taken into account for the orthotropic properties in the bone by testing only along the principle material axes, determined through microcomputed tomography. In addition, shaping of the stress wave pulse is used to ensure a constant strain rate and homogeneous specimen deformation. Results indicate that the strength of trabecular bone increases by a factor of approximately 2-3 when the strain rate increases from 10(-3) s(-1) to 500 s(-1) and that the bone fractures beyond a critical strain.

Abstract P4-06-24: KLF8 Induction of Mammary Epithelial Stem Cell Formation and Tumorigenesis by Regulating EMT-Associated MicroRNAs

Although it is well established that the epithelial-mesenchymal transition (EMT) generates cells with properties of stem cells, the molecularmechanisms responsible for this change remain largely undefined. We set out to identify the mechanisms by examining the expression of stem cell markers as well as microRNAs in MCF-10A cells during EMT induction. By immunostaining and FACS analysis, we found that during EMT induction by either TGF-β treatment or overexpression of KLF8, both the expression of CD44high/CD24low and the activity of aldehyde dehydrogenase (ALDH) were dramatically increased. Using microRNA PCR array, we identified a microRNA signature associated with the EMT. Using microRNA inhibitor, We further demonstrated that one of the microRNAs, miR-146a, is upregulated and plays an important role in keeping the stem cell percentage during EMT induced by both TGF-β and KLF8, as revealed by manipulation of miR-146a expression, analysis of the stem cell markers and mammosphere growth. Taken together, these results highlight a novel role for miR-146a in regulating the stem-like cell induction from MCF-10A cells by EMT. Experiments are in progress to investigate the contribution of KLF8-regulated expression of miR146a and its targets to the stem cell induction and transformation. Supported by: NIH, ACS, Komen and NYSTEM grants to J.Z.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-06-24.

Abstract P3-05-01: “VISA” Nanopaticles to Breast Cancer In Vitro and in Living Imaging Animal Models

Development of cancer gene therapy has been hampered by the fact that there are no effective cancer-specific expression vectors available, which is critical for improving therapeutic efficacy and reducing toxicity in clinics. To overcome this problem, we recently developed a safe and effective strategy fro targeting a potent pro-apoptotic gene (BikDD) to the pancreatic tumors (Xie et al. Cancer Cell, 2007), lung cancer (Sher et al. Oncogene, 2009) and ovarian cancer (Xie et al. Molecular Cancer Therapeutics, 2009). A VISA system (VP16-Gal4-WPRE integrated systemic amplifier) was engineered by using the two-step transcriptional amplification (TSTA) system and the posttranscriptional regulatory element of the woodchuck hepatitis virus (WPRE). The VISA system can boost the activity of cancer-specific promoters by an average of 600-800-folds compared to their basal levels. C-VISA (CCKAR-VISA) nanoparticles transcriptionally targets transgene expression effectively to pancreatic tumors in vivo. C-VISA-BikDD nanoparticles was shown to be highly effective in reducing tumor burden and increasing animal survival rate in orthotopic pancreatic cancer models which is moving into clinical trials at University of Texas M.D. Anderson Cancer Center, USA. In the current study, we identified hTERT(human telomerase reverse transcriptase), survivin, β-cateinin, claudin-4, and FASN (fatty acid synthase) promoters as breast cancer-selective promoters, and amplified their activity to hundreds of folds greater by the “VISA” system(called x-VISA) without loss of their specificity. Very importantly, the x-VISA promoters were also robust in the primary cultured breast cancer cells, with 42.5 %-65% of the CMV promoter, while retaining stringent pancreatic cancer specificity. x-VISA was also shown to target expression of firefly luciferase to MDA-MB-468 xenografts in an orthotopic mouse model, confirmed by noninvasive imaging with an Xenogen IVIS™ imaging system and measuring with a luminometer. The cancer-specific index was 35-60 for x-VISA-Luc and 0.01 for CMV-Luc in vivo. We further demonstrated significant antitumor activity of targeted BikDD expression driven by nanoparticles of the hTERT-VISA-BikDD vectors in Her-2-negative and-positive and triple-negative breast cancer cell lines in vitro, and in multiple breast cancer models of living imaging by the Xenogen IVIS imaging system with limited toxicity. In addition, treatment with hTERT-VISA-BikDD nanoparticles plus lapatinib or produces evident combinational therapeutic efficacy, which is likely due to the ability of lapatinib to promote apoptosis of Her-2-overexpressing breast cancer cells. Thus, our newly developed hTERT-VISA-BikDD nanoparticles are an innovative strategy for targeted antitumor effects of Her-2-negative, Her-2-positive and triple-negative breast cancer.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-05-01.

Abstract P4-06-23: KLF8 Is Regulated by Its Novel Interacting Protein PARP-1

Krüppel-like factor 8 (KLF8) plays an important role in the progression of breast cancer invasion and metastasis. Using mass spectrometry and co-immunoprecipitation, we identified PARP-1, a chromatin-associated enzyme that catalyzes protein poly(ADP-ribosyl)ation (PARylation), as a novel KLF8 interacting protein. Co-IP and western blotting indicated that KLF8 is a PARylation substrate. Mutation of the cystein residues in the first and second zinc-finger motifs of KLF8 abolishes its interaction with PARP-1. Luciferase assays showed KLF8 activation on the cyclin D1 promoter was significantly reduced when PARP-1 was physically deleted or functionally inhibited or when KLF8-PARP-1 interaction was disrupted. Surprisingly, immunofluorescent staining demonstrated that KLF8 was localized in the nuclei of wide type MEFs, but was mislocalized in the perinuclear cytoplasm of the PARP-1-/- cells, which could be rescued by re-expression of PARP-1. The detection of γH2A.X, comet assay and clonogenic assay indicated KLF8 play a DNA repair role in a PARP-1- dependent matter. Cychloheximade-chase assay revealed the stability of KLF8 dramatically reduced by loss of PARP-1 or when KLF8-PARP-1 interaction was disrupted, meanwhile ubiquitination assay showed heavier ubiquitin chains of KLF8. This work has identified PARP-1 as a novel binding partner and post-translational modifier of KLF8 and a critical regulator of KLF8 localization, functions and stability in the cells and suggested a critical role of the interaction between KLF8 and PARP1 during metastatic progression of breast cancer. Support by: NIH, ACS and Komen grants to J.Z.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-06-23.

Abstract P6-01-06: Identification of Molecular Subtypes of DCIS and Invasive Breast Cancer Using Computerized Image Analysis for Data Integration

Background: Breast cancer is a heterogeneous disease with different putative therapeutic targets based upon the particular subtype. The particular subtype can have profound implications for therapy, as in the case of basal-like carcinomas which tend to be more aggressive with less therapeutic options. Although many studies have examined the transition from Ductal Carcinoma in-situ (DCIS) to Invasive Breast Cancer (IBC), the mechanisms involving the transformation are poorly understood. DCIS cases that are more likely to progress to IBC can be treated more aggressively. This study used image analysis to examine the association between predictive molecular biomarkers between pure DCIS, DCIS associated with IBC and IBC.

Methods: With approval by the Institutional Review Board, we evaluated tissue microarrays comprising 453 tissue cores from 149 patients. Five immunohistochemical biomarkers were utilized: estrogen (ER), progesterone (PR), human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor (EGFR), and cytokeratin 5/6 (CK-5/6). We then employed the Automated Cellular Image Analysis (ACIS) to score the biomarker status. We compared regional scoring (rated 0, 1, 2, or 3) between an experienced pathologist's subjective assessment and an automated score derived from ACIS. An image library was generated and integrated to our Translational Data Mart (TraM: http://tram.uchicago. edu). Statistical analyses included a comparison of histological grade, race, age, tumor size, and lymph node status associated with the prevalence of subtypes between pure DCIS tumors and those that advanced to IBCs. Results: The concordance between ACIS-based and pathologist-based scoring was moderate (kappa = 0.38). There was more variability in the pathologist's scoring with a standard deviation of 1.14 as compared to 0.85 for ACIS. Subtypes associated with IBC were also present in DCIS. In the pure DCIS cases, there was a higher proportion of the luminal A subtype (74.1%, n = 54) as compared to DCIS adjacent to IBC (54.2%, n=24) or pure IBC cases (57.4%, n = 115) (p=0.05). In contrast, there was more basal-like subtypes in DCIS juxtaposed with IBC (20.8%) and IBC (27.8%) than in pure DCIS tumors (9.3%).

Discussion: Molecular subtype analysis of DCIS could be useful in predicting DCIS with high risk of progressing to invasive cancer. The resemblance between subtypes bolsters the hypothesis that IBCs and DCIS originate from the same precursor lesion. Although the automated scoring featured by ACIS would be useful in expediting readings, it must be validated by a pathologist's assessment.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-01-06.

Abstract P4-06-14: Induction of Blimp-1 in Breast Cancer Cells Is Mediated by Activator Protein-1 and Promotes Transforming Growth Factor (TGF)-ß-Induced Epithelial-to-Mesenchymal Transition

The vast majority of breast cancers has been shown to display aberrant constitutive expression of NF-kB subunits, which enhances their mobility and promotes their survival and malignancy. Recently, we demonstrated that the RelB NF-kB subunit promotes migration of breast cancer cells, in part via repression of estrogen receptor (ER)α transcription. Furthemore, we showed that inhibition of the ERα promoter was mediated by the zinc finger transcriptional repressor B lymphocyte-induced maturation protein (Blimp-1), transcribed from the PRDM1 gene, which is induced by RelB-mediated activation of a Bcl-2/Ras pathway. Indeed, we showed for the first time that Blimp-1 is present in breast cancer and is more highly expressed in ERα negative breast cancer cells where it plays an essential role in their migratory and invasive abilities. Blimp-1 is a well-known zinc finger repressor, which is critical for terminal differentiation of B and T cells and for migration of primordial germ cells. Here we have examined the mechanism of activation of Blimp-1 expression in breast cancer cells. Given the role of Ras to c-Raf signaling in migration of cancer cells, we tested the role of this downstream mediator. A constitutively active c-Raf led to induction of Blimp-1 in breast cancer lines while a dominant negative variant reduced its levels. RelB/p52 NF-kB complexes induced c-Jun, c-Fos, Fra-1 and Fra-2 Activator Protein-1 (AP-1) subunits, which activated the PRDM1 gene promoter. The transforming growth factor (TGF)-β induces a more mesenchymal phenotype of breast cancer cells. Treatment of NMuMG breast epithelial cells with TGF-β led to Blimp-1 activation through AP-1 and epithelial-to-mesenchymal transition (EMT). Importantly, Blimp-1 knockdown counteracted TGF-mediated EMT and wound healing in both NMuMG and MDA-MB-231 breast cells. Thus, activation of AP-1 complexes via a Ras/Raf/Erk signaling pathway mediates induction of PRDM1 gene transcription and Blimp-1 expression in ERα negative breast cancer cells, which is essential for TGF-β-induced mesenchymal phenotype. Therefore, downstream mediators of Blimp-1 activity might emerge as new therapeutic targets for treatment of patients with ERα negative breast cancer.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-06-14.

Frequency-domain streak camera for ultrafast imaging of evolving light-velocity objects

We demonstrate a frequency-domain streak camera (FDSC) that captures the picosecond time evolution of luminal-velocity refractive index structures in a single shot. In our prototype FDSC, a probe-reference pulse pair propagates obliquely to a subpicosecond pump pulse that creates an evolving nonlinear index structure in glass, supplementing a conventional frequency-domain holographic probe-reference pair that copropagates with the pump. A single spectrometer acquires data from both pairs via spatial or temporal multiplexing, demonstrating the feasibility of a compact frequency-domain tomographic system in which a single spectrometer processes data from multiple probing angles.

Abstract P5-05-05: Tazarotene-Induced Gene 1(TIG1) Is a Novel Tumorigenic Gene of Inflammatory Breast Cancer

Background: Inflammatory breast cancer (IBC) is the most lethal and aggressive form of advanced breast cancer. Effective standard therapies for IBC are limited and the molecular mechanisms underlying IBC are largely unknown. In a comparison of samples from patients with IBC and non-IBC, our laboratory identified TIG1 (tazarotene-induced gene 1), also known as retinoic acid receptor responder 1 (RARRES1) as the gene with the largest difference in expression between the two groups. TIG1 is specifically expressed in IBC cell lines (SUM149 and KPL-4). In addition, TIG1 has been identified as a top druggable gene for triple-negative breast cancer. Of particular interest is that TIG1 is significantly expressed in IBC ER-/HER2- patient samples when compared with non-IBC ER-/HER2- patient samples (p = 0.084).Therefore, we hypothesize that TIG1 plays an important role in the malignant process of IBC and it promotes the tumorigenesis and metastasis of IBC. In these studies we determined the tumorigenic and metastatic activities of TIG1 in IBC.

Methods: TIG1 was stably knocked down in the highly TIG1-expressing IBC cell line SUM149 and the effects of knockdown on cell proliferation, migration, invasion, and growth in three-dimensional culture were analyzed in vitro. To evaluate the tumorigenic activity of TIG1 in vivo, TIG1 stable-knockdown SUM149 cells and control shRNA-transfected cells were implanted into the mammary fat pads of athymic nude mice, and tumor growth was monitored. To investigate the underlying mechanism of TIG1- mediated tumorigenesis and metastasis of IBC, the gene expression profiles of control siRNA-transfected and TIG1 siRNA-transfected SUM149 cells were compared using cDNA microarray analysis.

Results: Suppressing TIG1 significantly inhibited the proliferation, migration, and invasion of IBC cells in vitro. SUM149 cells exhibit a mesenchymal-like phenotype when grown in three-dimensional culture. However, knocking down TIG1 reversed the mesenchymal-like phenotype to the epithelial phenotype in three-dimensional culture, suggesting that TIG1 might have metastatic activity in IBC cells. TIG1 knockdown dramatically inhibited IBC tumor growth in a xenograft model. Several differentially expressed genes between control siRNA-transfected and TIG1 siRNA-transfected SUM149 cells, including Decorin, GBP1, and VAV3 were identified using cDNA microarray analysis. These genes have been reported to affect a number of biological processes, including proliferation, metastasis, inflammatory response, and angiogenesis. We will focus on these candidates and determine the molecular mechanism by which TIG1 may function as a tumorigenic gene in IBC.

Conclusion: Our data demonstrate that TIG1 promotes the tumorigenesis and metastasis of IBC and it may contribute to the development and aggressiveness of IBC. Our long-term goal is to develop TIG1 as a therapeutic target for this extremely aggressive type of breast cancer.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-05-05.

Pulmonary toxicity in mice exposed to low and medium doses of water-soluble multi-walled carbon nanotubes

Carbon nanotubes (CNTs) are a class of new allotrope of carbon. Different functionalized CNTs may vary from their physical and chemical properties to the biological property. In this study, the toxicity of water-soluble taurine multi-walled CNTs (tau-MWNTs), raw MWNTs and positive control crystalline silicon dioxide particles on mouse lungs via intratracheal instillation (i.t.) was investigated. The dosages we used were 0.125, 0.25, 0.5 or 1 mg/kg of tau-MWNTs and raw MWNTs, and 1 mg/kg of silicon dioxide particles; Serum and lungs were collected at 1, 7, 14 or 28 days postexposure. The biochemical and cellular parameters were assessed, which include the ratio of the lung weight and body weight (lung indices), lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and angiotensin converting enzyme (ACE) in serum, and malondialdehyde (MDA), reduced glutathione (GSH), total sulfhydryl group (TSH) in lung tissue homogenates as well as the hydroxyproline in lungs. The characteristic recovery of the lung injury at 28 days postexposure was examined by the assessment of LDH, ALP, lung indices, and histopathology. ACE, MDA, GSH, TSH and histopathological changes showed that tau-MWNTs were less toxic than the raw MWNTs. Histopathological and ultrastructural investigation indicated that the acute pulmonary inflammation in lungs alleviated after 7d postexposure, and were greatly recovered within 28d. Meanwhile, the entrapment of tau-MWNTs reduced greatly by the 28d postexposure. Whereas the heavier pathologic changes induced by raw MWNTs lasted 7 days more than that of tau-MWNTs. Notably, no occurrence of granulomas and fibrosis were found in this study both in the two CNTs samples through 28d postexposure. Silicon dioxide particles, on the contrary, produced more severe damage to lungs than CNTs did in lung index, as well as other biochemical and cellular parameters. These findings indicate that water-soluble tau-MWNTs in low and medium doses induce slight and recoverable pulmonary inflammation in mice, and are less toxic than the insoluble raw MWNTs.