The Role of ALCAM, Activated Leukocyte Cell Adhesion Molecule, in the Aggressive Nature of Breast Cancer Cells, a Potential Connection to Bone Metastasis

Introduction. ALCAM, activated leukocyte cell adhesion molecule, has been previously reported to be connected to the progression of certain solid tumours. In breast cancer, ALCAM has been shown to be expressed at a reduced level in aggressive tumours (King et al 2004) and is a prominent feature for tumours subsequently developed bone metastasis (Davies et al 2008). In the present study, we investigate the molecular impact of ALCAM on the biological behaviours of breast cancer cells with a particular reference to condition that is linked to bone biological environment.Methods. A mammalian ALCAM expression construct was prepared from normal mammary cDNA bank using a pEF6.V5/His vector. Anti-ALCAM transgenes were prepared based on human ALCAM mRNA structure and cloned into a mammalian expression vector. Suitable cells were transfected with either the expression construct or anti-ALCAM transgene, to create sublines that had differential expression of ALCAM. The growth, migration and invasion of the aforementioned cells, together with their parent and control cell lines were evaluated using a panel of in vitro cell models, in the presence or absence of matrix proteins prepared from human bones. Statistical analysis was Student t test or Mann-Whitney test, where appropriate.Results. Of the 12 human breast cancer lines tested, ZR-75-1 was found to be strongly positive for ALCAM expression, whereas MDA-MB-231 was negative. ZR-75-1 was therefore transfected with the anti-ALCAM transgene. After selection, a subline, ZR-751ΔALCAM was created in which ALCAM expression was knocked out. Likewise, MDA-MB-231 was transfected with ALCAM expression construct, followed by creation of new subline, MDA-MB-231ALCAMexp, a sublined that over-expressed ALCAM. MDA-MB-231ALCAMexp cells showed a marginally slower rate of growth compared with control cells. However, in the presence of bone matrix proteins, MDA-MB-231ALCAMexp showed a significantly reduced rate of growth (growth index 0.62±0.11), p<0.01 vs control cells (1.06±0.15). In contrast, ZR-751ΔALCAM cells showed a faster pace of growth (1.04±0.14) compared with control cells (0.81±0.09). In an extracellular matrix based in vitro invasion assay, it was observed that MDA-MB-231ALCAMexp displayed a significantly reduced invasiveness compared with control cells (p=0.012). ZR-751ΔALCAM cells showed a significantly increased invasiveness vs its control cells (p=0.02). In an electric cell sensing based cell migration assay, we found that MDA-MB-231ALCAMexp cells showed marked reduction in migration compared with its control and parent cells. We have shown that inclusion of bone matrix proteins further reduced the migration speed of MDA-MB-231ALCAMexp cells.Conclusion. The present study provides cellular insight into the role of ALCAM in its involvement in bone metastasis of breast cancer. It is concluded that loss of ALCAM in breast cancer cells facilitates the invasive behaviour of breast cancer and highly levels of ALCAM in the cells have a suppressive role in the aggressive nature of breast cancer cells.1. Davies SR, et al, Oncol Rep., 2008, 19: 555-612. King JA et al, Breast Cancer Res., 2004, 6: R478-87

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6174.

Aberrant Expression of ARP2/3 in Breast Cancer and the Association with Disease Progression

Background: Increased motility is an important characteristics of neoplastic cells, a cell function mediated through actin polymerization. During this process, aside from creation of new branches and lengthening of pre-existing actin molecule, Actin-Related Proteins (ARP)- 2 and ARP-3 work as a complex promotes polymerization through production of new nuclei for actin polymerization. This regulation is orchestrated by other intracellular regulators including and WAVE and WASP proteins, which have been shown to be aberrant in breast cancer (1,2). In this study we determined the differential expression of ARP-2 and ARP-3 and correlated the expression with various prognostic factors.Methods: Expression of ARP-2 and ARP-3 was examined in a cohort of mammary tissues (n=33 normal breast tissue and n=127 primary breast tumor tissue samples). Transcript levels of ARP2 and ARP3 were then determined using quantitative real time PCR (Q-PCR) and protein levels were assessed using immunohistochemical (IHC) staining. Results were analyzed by Mann-Whitney U test.Results: Cytoplasmic staining for both ARP-2 and ARP-3 was noted along with strong epithelial staining as compared to stromal cells. Quantitative real time PCR (Q-PCR) data analysis showed lower expression of both ARP -2 & -3 in tumour tissue as compared to normal but without statistical significance. ARP-2 expression was significantly reduced in tumour samples from patients with poor prognosis (p=0.037) and patients who died of breast cancer (p=0.0265). Primary breast tumor tissue samples from patients classified as TNM stage 3 and 4 showed statistically significant lower expression of ARP-3 as compared to normal tissue (p= 0.019 and 0.020, respectively). ARP-3 expression was also significantly lower in patients who developed local recurrence of breast cancer (p=0.027). Using a Spearman correlation analysis, ARP-3 transcripts were find to be significantly correlated with the WAVE-2 transcript (r=0.42, p<0.01).Conclusions: Breast cancer shows aberrant expression of ARP-2 and ARP-3, a pattern linked to the prognosis of the patients. ARP-3 and WAVE-2 may have an intimate interplay in this association which warrants further investigation.References1. Fernando HS et al. Expression of the WASP verprolin-homologues (WAVE members) in human breast cancer. Oncology. 2007;73:376-3832. Martin TA, et al. N-WASP is a putative tumour suppressor in breast cancer cells, in vitro and in vivo, and is associated with clinical outcome in patients with breast cancer. Clin Exp Metastasis. 2008;25:97-108

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6169.

Prevalence and molecular diversity of Archaea in subgingival pockets of periodontitis patients

INTRODUCTION

The aim of this study was to investigate the prevalence and molecular diversity of Archaea in the subgingival crevices of patients with chronic periodontitis.

METHODS

Subgingival plaque was collected from 41 patients with chronic periodontitis and 15 healthy subjects. The prevalence of Archaea in those plaque samples was tested by polymerase chain reaction with two broad-range archaeal primer sets. Amplicons from eight Archaea-positive plaque samples were cloned and sequenced for molecular diversity analysis using one of these two primer sets and a novel third primer set.

RESULTS

Archaea were detected in the subgingival plaque of patients with chronic periodontitis at a prevalence of 70.7-73.2%, but were not detected in healthy subjects. Using one primer set, all sequences of the archaeal amplicons were identified as Methanobrevibacter oralis-like species. With another primer set, the amplicons were also found to be identical to the uncultured M. oralis-like species except one phylotype was found to belong to the class Thermoplasmata.

CONCLUSION

Archaea might be correlated with periodontal diseases. The diversity of Archaea associated with periodontitis was limited. Almost all sequenced amplicons fell into the genus Methanobrevibacter of the Euryarcheota phylum. M. oralis-like species was the predominant but non-exclusive archaeon in the subgingival dental plaque of patients with periodontitis.

Profile of volatile compounds in 11 brandies by headspace solid-phase microextraction followed by gas chromatography-mass spectrometry

A headspace solid-phase microextraction (HS-SPME) method coupled with gas chromatography-mass spectrometry (GC-MS) was applied for the qualitative or semiquantitative characterization of brandy volatiles. SPME variables (SPME fiber, extraction temperature and time, and ethanol concentration) were optimized. A total of 144 compounds were from the brandies' volatiles, tentatively identified or identified by comparing mass spectra and retention indices of the standards or from literature. Of these, 57 are common to 11 brandies. They were mainly represented by esters and alcohols, such as 2-methyl propanol, 3-methyl butanol, 1-hexanol, ethyl octanoate, and ethyl decanoate, which were quantitatively determined. Chromatographic peaks were integrated using selective ion method (SIM) and the semiquantitative data analyzed using principal component analysis (PCA) and cluster analysis (CA) to study relationships between volatile composition and brandy. Eleven brandies were differentiated into 3 groups: 1 for Hennessy VSOP and XO samples, 1 for Changyu PEGASE VSOP and XO-1, 2, 3 samples, and the other for Changyu PEGASE brandy and VO, Taro brandy, Baiyang River brandy, and Wealth XO samples. The classification of groups is consistent with the brandy samples by variety and grade.

Predictive values of intratumoral microvascular density (MVD) in the patients (pts) with advanced NSCLC and metastatic colorectal cancer (mCRC) receiving chemotherapy plus bevacizumab

e14618

Background: The using of bevacizumab (VEGFR inhibitor) combined with chemotherapy represents a most noticeable recent advance in clinical oncology for significantly improving pts’ survival in several tumor types. There is an unmet need for seeking biomarker(s) to predict the treatment response of bevacizumab and identify the pts sensitive to the treatment. Our study was designed to investigate the predictive value of intratumoral MVD in NSCLC and mCRC pts treated with bevacizumab. Method: Sixteen NSCLC (stage IIIB/IV) and 15 mCRC pts who underwent chemotherapy (paclitaxel+carbo for NSCLC and IFL for CRC, respectively) combined with Bevacizumab were included into this study. The paraffin-embedded tumor samples (13/16 NSCLC and all CRC samples were collected from primary tumor) were sectioned and stained immunohistochemically for blood vessel markers (CD34 and CD31) to identify the characteristics of intratumoral vasculature. A computerized image analysis program was used to quantitatively calculate the intratumoral MVD (Yao et al., Clin Cancer Res 2007). Treatment response was evaluated by computed tomography scanning. Results: Two types of blood vessel, undifferentiated (CD31+/CD34-) and differentiated (CD34+), were identified. For the 16 NSCLC pts, a positive correlation was found between the largest tumor shrinkage percentage (evaluate in the primary tumors and metastases) and the total (CD31+) MVD as well as the undifferentiated (CD31+/CD34-) MVD, with Spearman's correlation coefficients equaled to 0.567 (p=0.022) and 0.576 (p=0.019), respectively. However, no significant correlation between tumor shrinkage and MVD was found in CRC pts, in which the treatment response was evaluated in metastatic lesions while the MVD was calculated in primary tumor. Conclusion: This exploratory analysis suggests higher total vessel and undifferentiated vessel MVD appeared to be predictive of bevacizumab treatment advantage for advance NSCLC pts.Our study also indicated that the MVD of primary lesions did not correlate with the treatment response of metastatic lesions in CRC pts. Further studies are needed to verify the predictive role of MVD in the treatment of bevacizumab in NSCLC.

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The oligomeric subunit C rotor in the fo sector of ATP synthase: unresolved questions in our understanding of function

We have proposed a model for the oligomeric c-rotor of the F(o) sector of ATP synthase and its interaction with subunit a during H+-transport driven rotation. The model is based upon the solution structure of monomeric subunit c, determined by NMR, and an extensive series of cross-linking distance constraints between c subunits and between subunits c and a. To explain the complete set of cross-linking data, we have suggested that the second transmembrane helix rotates during its interaction with subunit a in the course of the H+-translocation cycle. The H+-transport coupled rotation of this helix is proposed to drive the stepwise movement of the c-oligomeric rotor. The model is testable and provides a useful framework for addressing questions raised by other experiments.

Estimating contrast transfer function and associated parameters by constrained non-linear optimization

The three-dimensional reconstruction of macromolecules from two-dimensional single-particle electron images requires determination and correction of the contrast transfer function (CTF) and envelope function. A computational algorithm based on constrained non-linear optimization is developed to estimate the essential parameters in the CTF and envelope function model simultaneously and automatically. The application of this estimation method is demonstrated with focal series images of amorphous carbon film as well as images of ice-embedded icosahedral virus particles suspended across holes.

Overexpression of L1CAM accompanies acquired endocrine resistance and is associated with the development of an aggressive cell phenotype

Abstract #3028

Background: Acquired resistance to endocrine therapies is associated with a gain in aggressive features in vitro which may impact on tumour spread in vivo. To identify potential candidate molecules which may promote this adverse cell behaviour, we performed microarray analysis on MCF-7 cell models of fulvestrant resistance ('FasR' cells) applying a commercial algorithm for signalling network discovery. We have subsequently investigated the significance of overexpression of L1CAM, a cell-surface adhesion molecule implicated in a MAPK signalling network and recently associated with tumour metastasis, in FasR cells and in clinical tissue.
 Materials and Methods: A network analysis algorithm was applied to t-test significant Affymetrix gene lists derived from FasR vs. MCF-7 cells (Almac Diagnostics). Subsequent to revealing a prominent L1CAM network, L1CAM gene and protein expression were assessed using RT-PCR, Western blotting and immunofluorescence. Inhibition of L1CAM was achieved using siRNA transfection. Cell invasion and migration were measured by seeding onto Matrigel- or fibronectin-coated microporous membranes respectively. After 48 hours, invasive/migratory cells were fixed, stained and counted. Analysis of cell signalling molecules was determined using Western blotting with phospho-specific antibodies. Clinical significance of L1CAM expression was determined by analysis of L1CAM expression in tumour (n=101) vs. normal (n=23) breast tissue using Q-PCR.
 Results: Development of fulvestrant resistance in MCF7 cells was associated with ER loss and a gain in migratory and invasive capacity in vitro. L1CAM was overexpressed at both gene (p<0.05) and protein (p<0.01) level in FasR cells whereas little or no L1CAM was detectable in MCF7 cells confirming microarray findings. Network and ontological analysis predicted L1CAM lies upstream of an ERK2 network (26 genes; p<0.0001) impinging on transcription factors/regulators which may promote aggressive cell behaviour. In agreement, siRNA-mediated inhibition of L1CAM suppressed the activity of nuclear MAP kinase and reduced the intrinsic migratory and invasive nature of FasR cells in vitro. Preliminary analysis indicated L1CAM expression was inversely associated with ER status (p<0.01) and reduced overall survival (p=0.01).
 Conclusions: These data suggest that L1CAM overexpression associates with emergence of ER-negative fulvestrant resistance in breast cancer, where it may confer a highly motile and invasive phenotype. Additionally, our clinical studies suggest L1CAM may also contribute to inherently aggressive, ER-negative breast cancers. L1CAM signalling may thus provide a new therapeutic target to subvert such aggressive states in vivo.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3028.

Differentiation of mouse nuclear transfer embryonic stem cells into functional pancreatic beta cells

AIMS/HYPOTHESIS

Therapeutic cloning has been reported to have potential in the treatment of several degenerative diseases. However, it has yet to be determined whether mouse nuclear transfer-embryonic stem cells (NT-ESCs) can be differentiated into pancreatic beta cells and used to reverse diabetes in an animal model.

METHODS

We first used the somatic nuclear transfer technique to generate mouse NT-ESCs and then developed a chemically defined stepwise protocol to direct the NT-ESCs into functional pancreatic beta cells. We examined the gene expression pattern of the differentiated NT-ESCs and transplanted the NT-ESC-derived insulin-producing cells into recipient diabetic mice.

RESULTS

Four mouse NT-ESC lines were first established using an improved nuclear transfer technique and insulin-producing cells were efficiently generated from NT-ESCs by mimicking pancreatic in vivo development. Most of the insulin-producing cells that we generated co-produced pancreatic and duodenal homeobox 1, but not glucagon at the final stage of this differentiation method, which differed from the insulin and glucagon co-production reported by other groups. The differentiated NT-ESCs were able to release insulin in response to glucose stimuli and normalise the blood glucose level of diabetic mice for at least 2 months.

CONCLUSIONS/INTERPRETATION

These results demonstrate the potential of therapeutic cloning for cell therapy of type 1 diabetes in a mouse model.

Indomethacin improves locomotor deficit and reduces brain concentrations of neuroinhibitory steroids in rats following portacaval anastomosis

Hepatic encephalopathy (HE) is a neuropsychiatric complication of both acute and chronic liver failure characterized by progressive neuronal inhibition. Some neurosteroids are potent positive allosteric modulators of the gamma-aminobutyric acid (GABA)-A receptor complex, and 'increased GABAergic tone' has been proposed to explain the neuroinhibition characteristics of HE. Brain levels of the neurosteroids pregnenolone, allopregnanolone and tetrahydrodesoxycorticosterone (THDOC) and the functional status of the GABA-A receptor complex were assessed in rats following portacaval anastomosis (PCA). Effects of indomethacin, an inhibitor of the 3alpha-hydroxysteroid dehydrogenase enzyme involved in neurosteroid synthesis, on PCA rat locomotor activity and brain neurosteroid levels were also assessed. Significant increases of the neurosteroid pregnenolone (2.6-fold), allopregnanolone (1.7-fold) and THDOC (4.7-fold) were observed in brains of PCA rats. Brain levels of these neurosteroids were in the nanomolar range, sufficient to exert positive allosteric modulatory effects at the GABA-A receptor. Indomethacin (0.1-5 mg kg(-1)) ameliorated dose-dependently the locomotor deficit of PCA rats and concomitantly normalized brain levels of allopregnanolone and THDOC. Increased brain levels of neurosteroids with positive allosteric modulatory actions at the neuronal GABA-A receptor offer a cogent explanation for the notion of 'increased GABAergic tone' in HE. Pharmacological approaches using agents that either reduce neurosteroid synthesis or modulate the neurosteroid site on GABA-A receptor could offer new therapeutic tools for the management and treatment of HE.

Quetiapine facilitates oligodendrocyte development and prevents mice from myelin breakdown and behavioral changes

Recent neuroimaging and postmortem studies have reported abnormalities in white matter of schizophrenic brains, suggesting the involvement of oligodendrocytes in the etiopathology of schizophrenia. This view is being supported by gene microarray studies showing the downregulation of genes related to oligodendrocyte function and myelination in schizophrenic brain compared to control subjects. However, there is currently little information available on the response of oligodendrocytes to antipsychotic drugs (APDs), which could be invaluable for corroborating the oligodendrocyte hypothesis. In this study we found: (1) quetiapine (QUE, an atypical APD) treatment in conjunction with addition of growth factors increased the proliferation of neural progenitors isolated from the cerebral cortex of embryonic rats; (2) QUE directed the differentiation of neural progenitors to oligodendrocyte lineage through extracellular signal-related kinases; (3) addition of QUE increased the synthesis of myelin basic protein and facilitated myelination in rat embryonic cortical aggregate cultures; (4) chronic administration of QUE to C57BL/6 mice prevented cortical demyelination and concomitant spatial working memory impairment induced by cuprizone, a neurotoxin. These findings suggest a new neural mechanism of antipsychotic action of QUE, and help to establish a role for oligodendrocytes in the etiopathology and treatment of schizophrenia.