Abstract P1-07-11: ERa regulates epithelial-mesenchymal transition in breast cancers through suppressing Bmi1 expression

Background: Bmi1, a polycomb-group protein, maintains stem cell self-renewal and is frequently overexpressed in cancers. Upregulation of Bmi1 by Twist1 can promote tumor-initiating capability and Epithelial-mesenchymal transition (EMT) by repressing E-cadherin expression. It has been demonstrated that Post-EMT breast cancer cells express cancer stem cell (CSC) markers including Bmi1, but display decreased ERα expression. ERα is a ligand-activated nuclear hormone receptor that regulates the transcription of E2-responsive genes in diverse target cells. It's reported that ligand-activated ERα could repress slug transcription by binding to the half-site ERE element in its promoter, and then regulate E-cadherin and EMT. Herein, we hypothesized that ERα signaling might regulate E-cadherin and EMT through Bmi1.

Methods: First, we determined Bmi1 and ERα expression at both mRNA and protein levels by quantitative RT-PCR and Western blot in various breast cancer cell lines. Further, we quantitatively analyzed mRNA and protein levels of Bmi1 as well as its down-stream genes including E-cadherin after silencing ERα in T47D cells with siRNA, or after overexpressing ERα in BT549 cells. The chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift assay (EMSA) were also performed to investigate whether ERα binds directly to Bmi1 promoter region. Luciferase assay with Bmi1 reporter was performed to ERα mediated regulation. To identify whether ERα regulates EMT, transwell and matrigel invasion, flow cytometry, mammosphere assay and wound healing assay were performed to invasion, metastases and characterize stem-cell properties of EMT. Finally, we analyzed the expression of ERα, Bmi1 and E-cadherin in human breast cancer specimens with immunohistochemistry.

Results: The study showed that Bmi1 inversely correlated with ERα expression in different subtypes of breast cancer cells. We further confirmed that Bmi1 was upregulated at both mRNA and protein levels and E-cadherin was downregulated with siRNA against ERα in T47D cells, and Bmi1 was downregulated and E-cadherin was upregulated when overexpressing ERα in BT549 cells with qRT-PCR and western blot analyses. The present study also demonstrated that ERα could directly binds to the half-ERE region of the Bmi1 gene and repressing Bmi1 expression transcriptionally with CHIP/EMSA and reporter analyses. Overexpression of ERα in BT549 cell significantly decreased levels of migration of transwell and wounding healing, invasiveness, CD44high/CD24low population, and the capabilities of mammosphere formation.

Conclusions: Our results demonstrated that ERα can suppress EMT through transcriptionally down-regulating Bmi-1 and its down-stream genes in human breast cancer cells. The inverse relationship between ERα and Bmi1 expression further supports the epithelial phenotype of ERα positive tumors or mesenchymal phenotype of ERα negative tumors. Our findings provide a novel mechanistic insight into how ERα regulates EMT, and is of valuable for developing biomarkers to predict prognosis and targeted therapies in breast cancers in the future.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-07-11.

Analysis of interventional treatments of Budd-Chiari Syndrome and the related complications: a study of 1006 cases

AIM

The aim of this paper was to investigate the cause of intraoperative and postoperative complications in Budd-Chiari syndrome (BCS) and its prevention.

METHODS

BCS Patients (1035) who were treated between 1990 and 2009 were included in the present study. Among these patients, there were 651 cases with inferior vena cava occlusion, 273 cases with hepatic vein obstruction and 111 cases with both the symptoms. Treatment for 28 patients failed due to various causes and 1 case diagnosed of obstruction in the right hepatic vein was not treated due to the compensation from the middle and left hepatic vein. The remaining 1006 cases were resolved by the percutaneous transluminal angioplasty (PTA), of which 746 cases had only PTA and 260 cases had both PTA and stent.

RESULTS

There were complications in 66 (6.56%) cases after intervention and 2 patients (0.199%) died. Accidental surgical penetration of the pericardium or cardiac tamponade (0.99%) led to the death of 10 patients, among which 4 cases had cardiac tamponade and one died due to the tamponade. In 2 (0.199%) patients there was stent migration into the right atrium from inferior vena cava. Pleural bleeding was seen in 1 case (0.099%) and abdominal bleeding in 2 cases (0.199%). Two cases (0.199%) had pulmonary obstruction. A single (0.099%) case had chocolate cyst rupture in thrombolytic process. Twenty-seven patients had acute re-stenosis after the surgery, among which 22 (2.95%, 22/746) had the stenosis after only PTA and 5 (1.92%, 5/260) had the stenosis after receiving both PTA and stent. 3 (0.298%) cases had pseudoaneurysm at the puncturing site. Puncture site bleeding and local hematoma was seen in 10 cases (0.99%), whereas 4 cases (0.398%) had leg phlebothrombosis on the same side of the puncture site.

CONCLUSION

Interventional treatment is a safe and effective way to treat BCS. Various effective measures should be taken to avoid and lower the incidence of complications.

Suppression of hepatoma tumor growth by systemic administration of the phytotoxin gelonin driven by the survivin promoter

Hepatocellular carcinoma (HCC) is one of the most common types of cancer worldwide. However, there is currently no effective therapy strategy in the clinical practice. Recombinant phytotoxin gelonin fused to other factors have been used to treat different cancers. But there have been no reports of gelonin gene therapy. In this study, we have constructed a recombinant plasmid which contained a tumor-specific survivin promoter to drive phytotoxin gelonin (pSur-Gel). And the cytotoxicity effects of pSur-Gel in HCC were also validated both in vitro and in vivo. The expression level of survivin was detected in different liver cancer cell lines and normal liver cell lines by western blot analysis, and a survivin promoter-driven green fluorescent protein (GFP) expression vectors (pSur-GFP) was also tested in liver cancer cell line HepG2 and normal liver cell line LO2. Moreover, phytotoxin gelonin expression experiment and cytotoxicity experiment of pSur-Gel was performed in HepG2 cells and LO2 cells in vitro. Furthermore, anti-tumor effect of pSur-Gel against HepG2 xenografts and toxicity of this gene were evaluated in the mice model. Finally, LDH release assay, apoptosis assay and immunoblot analyse LC3 conversion (LC3-I to LC3-II) were tested. We found that the expression of survivin protein was higher in liver cancer cell lines compared with the normal liver cells. Further study showed that the pSur-GFP and pSur-Gel was expressed specially in liver cancer cell other than in normal liver cells. pSur-Gel plasmid could effectively inhibit the proliferation of liver cancer cells (*P<0.05), and significantly repress the growth of HepG2 xenografts via intravenous in vivo (*P<0.05). Otherwise, compared to cytomegalovirus promoter-driven gelonin expression vectors (pCMV-Gel), no significantly systemic toxicity or organ injuries had been observed in pSur-Gel treated mice. Further studies revealed that the phytotoxin gelonin induced cell death might be mediated by apoptosis and the damage of cell membrane. Taken together, treating hepatocellular carcinoma with the pSur-Gel may be a novel and interesting cancer gene therapy protocol and is worthy of further development for future clinical trials.

KEYWORDS

liver cancer, gelonin, survivin promoter, gene therapy.

Blood plasma concentrations of endocrine disrupting chemicals in Hong Kong populations

In this study we report the human plasma concentrations of some common endocrine disrupting chemicals (EDCs) in the Hong Kong population. We have analyzed 153 plasma samples for the contaminants by methods involving labeled standards spiked into the samples. Quantification was performed using high performance liquid chromatography tandem mass spectrometry for bisphenol-A (BPA) and perfluorinated compounds (PFCs), and gas chromatography mass spectrometry methods for phthalates. We found BPA, several types of PFCs and phthalates in over 90% of the plasma samples. Perfluorooctane sulfonate (PFOS) was the dominant PFC, followed by perfluroroctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS). Eight out of ten phthalates were detected, with bis(2-ethylhexyl) phthalate (DEHP) as the most abundant, followed by bis(2-methoxyethyl) phthalate (DMEP) and dioctyl phthalate (DnOP). The levels of PFOS, PFOA, PFHxS and perfluorohexanoic acid (PFHxA) were significantly higher in the male plasma samples (p<0.05), while the mean plasma levels of DEHP and n-butyl benzyl phthalate (BBP) were significantly higher in the young age group (p<0.02). The presence of the selected EDCs in human blood plasma indicates common exposure routes among different population cohorts. Although the plasma levels of the EDCs were comparable to other countries, regular monitoring of human blood EDC contamination levels is necessary to provide a time-trend database for the estimation of exposure risk and to formulate appropriate public health policy.

Enhancement of long-term depression by soluble amyloid β protein in rat hippocampus is mediated by metabotropic glutamate receptor and involves activation of p38MAPK, STEP and caspase-3

It is reported that the amyloid-β protein (Aβ)-induced impairments in synaptic plasticity coincide with memory decline and dementia. Although Aβ-induced inhibition of hippocampal long-term potentiation has been intensively investigated, the underlying mechanism of Aβ-enhanced long-term depression (LTD) is not clear. Here, we report that acute exposure of rat hippocampal slices to soluble Aβ-enhanced LTD induced by weak low-frequency stimulation (wLFS; 1Hz for 3 min, 180 pulses) in granule cells of the dentate gyrus. Application of LY341495 (a non-selective Group I/II metrabotropic glumate receptor (mGluR) antagonist) completely blocked Aβ-enhanced LTD, whereas D-AP5 (a not selective N-methyl-d-aspartate receptor (NMDAR) antagonist) had no effect on Aβ-enhanced LTD compared with controls. In addition, Aβ-enhanced LTD was occluded by pre-application of 3,5-dihydroxyphenylglycine, a Group1 mGluR (mGluR1/5) agonist, suggesting Aβ-enhanced LTD depends on mGluR1/5 but not NMDAR. We also report here that p38 mitogen-activated protein kinase (p38MAPK) inhibitor SB203580 and postsynaptic protein tyrosine phosphatase inhibitors phenylarsine oxide and sodium orthovanadate prevented the facilitatory effect of Aβ on LTD. Application of striatal-enriched protein tyrosine phosphatase (STEP) activator MG132 facilitated induction of LTD by wLFS, but did not block following Aβ-enhanced LTD induced by another wLFS. On the other hand, Aβ-enhanced LTD blocked following MG132-LTD by wLFS, suggesting Aβ-enhanced hippocampal LTD involves STEP activation. Application of either non-selective caspase inhibitor Z-VAD-FMK or caspase-3 selective inhibitor Z-DEVD-FMK prevented Aβ-enhanced LTD. However, neither the tumor necrosis factor-α converting enzyme inhibitor TAPI-2 nor the mammalian target of rapamycin inhibitor rapamycin prevented the enhancement of Aβ on LTD. Therefore, we conclude that soluble Aβ enhances LTD in the hippocampal dentate gyrus region, and the facilitatory effect of Aβ on LTD involves mGluR1/5, p38MAPK, STEP and caspase-3 activation.

Mechanical compressive force inhibits adipogenesis of adipose stem cells

OBJECTIVE

The aim of this study was to investigate effects of mechanical compressive force on differentiation of adipose-derived stem cells (ASCs) in vitro.

MATERIALS AND METHODS

Mice ASCs were treated with compressive force (2000 με, 1 Hz) for 2 or 6 h after adipogenic induction for 3 days, then oil red O staining was used to examine oil droplet-filled cells. Adipogenic genes, PPAR-γ1 and APN, were examined by real-time PCR and immunofluorescence (IF) staining was performed to test expression of de-PPAR-γ and ph-PPAR-γ at the protein level.

RESULTS

Our data showed that mechanical compressive force reduced numbers of oil droplet-filled cells, and down-regulated mRNA levels of both PPAR-γ1 and APN and protein level of PPAR-γ, in ASCs.

CONCLUSIONS

In culture medium containing adipogenic stimuli, mechanical compressive force inhibited adipogenesis of ASCs.

Osteogenic differentiation of adipose-derived stem cells prompted by low-intensity pulsed ultrasound

OBJECTIVES

Based on in vivo studies, low-intensity pulsed ultrasound (LIPUS) stimulation has been widely used in the clinic for advancing bone growth during healing of non-union alignment, fractures and other osseous defects. In this study, we have investigated osteogenic differentiation of adipose stem cells (ASCs) regulated by LIPUS, and also in a preliminarily manner, we have discussed diverse effects of different duty ratio parameters.

MATERIALS AND METHODS

Mouse adipose stem cells were isolated and osteogenically induced. Then they were treated with LIPUS for 10 min/day for 3 days, 5 days and 7 days, respectively. Finally, effects of LIPUS on osteogenic differentiation of the ASCs were analysed by real-time PCR, western blotting and immunofluorescence.

RESULTS

Our data indicated that LIPUS promoted mRNA levels of runt-related transcription factor 2, osteopontin and osterix in the presence of osteo-induction medium; moreover, protein levels of runt-related transcription factor 2 and osteopontin were upregulated.

CONCLUSIONS

We successfully demonstrated that LIPUS enhanced osteogenesis of ASCs, specially at the duty ratio of 20%.

Low-intensity pulsed ultrasound induced enhanced adipogenesis of adipose-derived stem cells

OBJECTIVE

The aim of this study was to investigate effects of low-intensity pulsed ultrasound (LIPUS) on differentiation of adipose-derived stem cells (ASCs), in vitro.

MATERIALS AND METHODS

Murine ASCs were treated with LIPUS for either three or five days, immediately after adipogenic induction, or delayed for 2 days. Expression of adipogenic genes PPAR-γ1, and APN, was examined by real-time PCR. Immunofluorescence (IF) staining was performed to test for PPAR-γ at the protein level.

RESULTS

Our data revealed that specific patterns of LIPUS up-regulated levels of both PPAR-γ1 and APN mRNA, and PPAR-γ protein.

CONCLUSIONS

In culture medium containing adipogenic reagents, LIPUS enhanced ASC adipogenesis.

Relationship between diffusion-weighted imaging and Bcl-2 expression in rabbit models of hepatic VX2 tumors after radiotherapy

The paper aims to study diffusion-weighted imaging (DWI) and Bcl-2 gene expression in hepatic VX2 tumors after three-dimensional conformal radiotherapy (3D-CRT), we successfully developed 40 rabbit models with hepatic VX2 tumors. 3D-CRT was performed on 28 rabbit hepatic VX2 tumors, which were then randomly and evenly divided into four groups. The remaining 12 controls did not receive radiotherapy. Conventional and DWI was performed at 1, 5, 10, and 15 days following radiation therapy. We measured apparent diffusion coefficients (ADCs) in both a region of interest (ROI) of the VX2 tumor tissue and normal liver tissue and then calculated the ratio between them. RT-PCR was performed to detect the expression of the anti-apoptotic gene Bcl-2. On days 5 and 10, the ADC ratios of the radiotherapy groups were 1.322+-0.270 and 0.964+-0.341, respectively. On days 5, 10, and 15, Bcl-2 gene expression in the radiotherapy group was 0.563+-0.284, 0.421+-0.242, and 0.314+-0.152, respectively. For all three days, the gene expression values from the radiotherapy group were significantly lower than that in the control group (P less than 0.01). Statistical analysis revealed that ADC ratio and Bcl-2 gene expression were significantly negatively correlated (r=-0.493, P less than 0.01). Our results demonstrated that DWI sequence can reflect molecular changes at different time points for hepatic VX2 tumors following radiotherapy.

Thermosensitive polymeric hydrogels as drug delivery systems

Thermosensitive hydrogels are very important biomaterials used in drug delivery systems (DDSs), which gained increasing attention of researchers. Thermosensitive hydrogels have great potential in various applications, such as drug delivery, cell encapsulation, tissue engineering, and etc. Especially, injectable thermosensitive hydrogels with lower sol-gel transition temperature around physiological temperature have been extensively studied. By in vivo injection, the hydrogels formed non-flowing gel at body temperature. Upon incorporation of pharmaceutical agents, the hydrogel systems could act as sustained drug release depot in situ. Injectable thermosensitive hydrogel systems have a number of advantages, including simplicity of drug formulation, protective environment for drugs, prolonged and localized drug delivery, and ease of application. The objective of this review is to summarize fundamentals, applications, and recent advances of injectable thermosensitive hydrogel as DDSs, including chitosan and related derivatives, poly(N-isopropylacrylamide)-based (PNIPAAM) copolymers, poly(ethylene oxide)/poly(propylene oxide) (PEO/PPO) copolymers and its derivatives, and poly(ethylene glycol)/ biodegradable polyester copolymers.

On the synthesis and physical properties of iron doped SnO2 nanoparticles

The synthesis of iron doped tin oxide by pulsed laser pyrolysis is reported. The as obtained nanoparticles have a dominant SnO2 phase (as revealed by Wide Angle X-ray Scattering), with particles of the order of 10 nm. The doping with iron or iron oxide triggers magnetic properties as confirmed by SQUID experiments. EDX measurements supported the presence of Fe while Wide Angle X-ray Scattering failed to sense any iron or iron-oxide phase. It is concluded that Fe is well dispersed within the tin-oxide nanoparticles. The coercitive field has a complex dependence on the Fe/Sn content suggesting that the magnetization is not controlled solely by the amount of Fe dispersed within the nanoparticles.

Jagged-1-mediated activation of notch signalling induces adipogenesis of adipose-derived stem cells

OBJECTIVES

Notch signalling plays an important role in many cell activities, involving proliferation, migration, differentiation and cell death. The aim of this study was to investigate effects of such signalling on adipogenesis of mouse adipose-derived stem cells (mASCs).

MATERIALS AND METHODS

Jagged1 (50 and 100 ng/ml) was added to mASCs to activate Notch signalling, 2 days before adipogenic induction. At 5 and 7 days after induction, oil red-O staining was performed to evaluate lipid accumulation. Then real-time PCR was performed to examine expression of Notch downstream genes (Notch-1, -2, Hes-1 and Hey-1) and adipogenic transcription factor (PPAR-γ). Expressions of Hes-1 and PPAR-γ at protein level were confirmed by immunofluorescence staining.

RESULTS

Our data indicated that Jagged1 promoted adipogenic differentiation of mASCs. Moreover, Jagged1 also increased expression of Notch downstream genes and PPAR-γ. Expressions of Hes-1 and PPAR-γ were found to be enhanced in Jagged1 pre-treated mASCs when compared to controls.

DISCUSSION

The results led to the conclusion that activation of Notch signalling had stimulated adipogenesis of mASCs in the presence of adipogenic medium by promoting expression of PPAR-γ.

Dielectric wakefield acceleration of a relativistic electron beam in a slab-symmetric dielectric lined waveguide

We report first evidence of wakefield acceleration of a relativistic electron beam in a dielectric-lined slab-symmetric structure. The high energy tail of a ∼60  MeV electron beam was accelerated by ∼150  keV in a 2 cm-long, slab-symmetric SiO2 waveguide, with the acceleration or deceleration clearly visible due to the use of a beam with a bifurcated longitudinal distribution that serves to approximate a driver-witness beam pair. This split-bunch distribution is verified by longitudinal reconstruction analysis of the emitted coherent transition radiation. The dielectric waveguide structure is further characterized by spectral analysis of the emitted coherent Cherenkov radiation at THz frequencies, from a single electron bunch, and from a relativistic bunch train with spacing selectively tuned to the second longitudinal mode (TM02). Start-to-end simulation results reproduce aspects of the electron beam bifurcation dynamics, emitted THz radiation properties, and the observation of acceleration in the dielectric-lined, slab-symmetric waveguide.

Myotonia congenita with strabismus in a large family with a mutation in the SCN4A gene

BACKGROUND/AIMS

To determine the genetic basis of myotonia congenita (MC) and strabismus in a large Caucasian family.

METHODS

Seven patients making up four generations of a family with MC and strabismus were recruited. All patients had at least one standard ophthalmic examination, including best-corrected visual acuity, refraction, and ocular motility measurements. CLCN1 and SCN4A genes were sequenced and analysed for mutations.

RESULTS

Five out of the seven family members were diagnosed with MC by clinical history and electromyography. Ophthalmic history and exam revealed eyelid myotonia and strabismus. All patients with MC were diagnosed with strabismus between the ages of 3 and 6 and required surgical restoration of ocular alignment. Sequencing results revealed a c. 1333G>A; p. Val445Met mutation in the SCN4A gene.

CONCLUSION

There are few reports describing eyelid myotonia and strabismus in patients diagnosed with MC. We found significant ocular involvement in a family with a mutation in SCN4A. Future studies may confirm that MC with significant ocular involvement can be used to direct genetic analysis.