Abstract P2-09-19: Expression Profiling of a Metastasis Score and a “Glycolytic Index” in Genetically-Defined Human Breast Isogenic Cell Lines Treated with a PI3K Inhibitor

Background: Activation of signaling pathways, loss of tumor suppressors and oncogenic mutations often lead to dysregulation of glycolysis and tumorigenesis. We performed expression analysis on genetically-defined human isogenic breast cancer cell lines and with PI3K inhibitor exposure to determine impact on a patient-relevant Metastasis Score (MS) (proliferation index) and an assembled “glycolytic index”. A better understanding of the links between cellular metabolism and proliferation may yield insights into tumor cell biology and shed light on potential companion diagnostic and therapeutic opportunities.

Methods: A parental MCF10A and three isogenic cell lines harboring K-ras (G12V), PI3Kα (H1047R), and p53 null were grown overnight in the presence of high levels of growth factors in tissue culture flasks. The parental and PI3Kα cells were treated with 0.3 µM, 1 µM,3 µM GDC-0941 or DMSO. All cell lines were incubated for an additional 24 hr. RNA was extracted with RNeasy (Qiagen) and expression analysis performed by RT-PCR. A total of 28 genes were profiled that included 14 genes in a metastasis score (MS) (Tutt et al), 11 glycolysis-associated genes and 3 reference genes. Expression of each gene was calculated using the ΔΔCT method and “summed” with equal weighting to yield an MS and a “glycolytic index”.

Results: The MS and phenotypes for the four untreated cell lines were similar under the monolayer culture conditions used. The parental and PI3Kα cells had a similar “glycolytic index” while p53 null and K-ras cells had elevated indices. Treatment of the parental and PI3Kα with GDC-0941, a PI3K inhibitor, showed a dose-dependent decrease in the expression of constituent MS genes and the glycolytic genes as well as the combined scores. The correlation coefficient between MS and the glycolytic index was 0.77. The four genes in MS with the greatest dose-dependent decrease in expression (BUB1, CCNB1, MYBL2 and UBE2S) are associated with CDK1, a seminal participant in cell cycle regulation. The two genes from the “glycolytic index” with the greatest decrease, HK and PKM, are directly involved in glycolysis. The effect of GDC-0941, as reflected by MS and the “glycolytic index” was more pronounced in PI3Kα than the parental cells (p-value=0.0005).

Conclusion: The good correlation observed between the MS and “glycolytic index “in the treated cell lines supports an association between proliferation and metabolism upon restriction of cell signal transduction. The dose-dependent expression decreases in the two indices and their constituent genes, suggest that this PI3K inhibitor successfully perturbs both fundamental processes of the cell. Given the ultimate targeting of proliferation suppression, these scores may serve as useful tools in evaluating therapeutic agents, independent of the specific intended pathways. The similar proliferation levels observed in untreated MCF10A and three mutated cell lines suggest either that single oncogenic mutations are insufficient to affect MS or that the in vitro conditions are masking the metastatic/invasive phenotype. Studies are underway to evaluate cells grown in 3D Matrigel that more accurately mimic the tumor microenvironment.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-09-19.

Schwann-like cell differentiation of rat adipose-derived stem cells by indirect co-culture with Schwann cells in vitro

OBJECTIVES

Schwann cell (SC) transplantation is a promising therapy for peripheral nerve transaction, however, clinical use of SCs is limited due to their very limited availability. Adipose-derived stem cells (ADSCs) have been identified as an alternative source of adult stem cells in recent years. The aim of this study was to evaluate the feasibility of using ADSCs as a source of stem cells for differentiation into Schwann-like cells by an indirect co-culture approach, in vitro.

MATERIALS AND METHODS

Multilineage differentiation potential of the obtained ADSCs was assayed by testing their ability to differentiate into osteoblasts and adipocytes. The ADSCs were co-cultured with SCs to be induced into Schwann-like cells through proximity, using a Millicell system. Expression of typical SC markers S-100, GFAP and P75NTR of the treated ADSCs was determined by immunocytochemical staining, western blotting and RT-PCR. Myelination capacity of the differentiated ADSCs (dADSCs) was evaluated in dADSC/dorsal root ganglia neuron (DRGN) co-cultures.

RESULTS

The treated ADSCs adopted a spindle shaped-like morphology after co-cultured with SCs for 6 days. All results of immunocytochemical staining, western blotting and RT-PCR showed that the treated cells expressed S-100, GFAP and P75NTR, indications of differentiation. dADSCs could form Schwann-like cell myelin in co-culture with DRGNs. Undifferentiated ADSCs (uADSCs) did not form myelin compared to DRGNs cultured alone, but could produce neurite extension.

CONCLUSIONS

These results demonstrate that this indirect co-culture microenvironment could induce ADSCs to differentiate into Schwann-like cells in vitro, which may be beneficial for treatment of peripheral nerve injuries in the near future.

Sialyl Lewis X modification of the epidermal growth factor receptor regulates receptor function during airway epithelial wound repair

BACKGROUND

Epidermal growth factor receptor (EGFR) is a major regulator of airway epithelial cell (AEC) functions such as migration, proliferation and differentiation, which play an essential role in epithelial repair. EGFR is a glycoprotein with 12 potential N-glycosylation sites in its extracellular domain. Glycosylation of EGFR has been shown to modulate its function. Previously, our laboratory demonstrated an important role of the carbohydrate structure sialyl Lewis x (sLe(x)) in airway epithelial repair.

OBJECTIVE

To examine whether an sLe(x) decoration of EGFR can modulate receptor function during AEC repair.

METHODS

Primary normal human bronchial epithelial (NHBE) cells were cultured in vitro. Co-localization of sLe(x) and EGFR was examined using confocal microscopy. Expressions of RNA and protein were analysed using RT-PCR and Western blotting. The final step in the synthesis of sLe(x) was catalysed by a specific alpha-1,3-fucosyltransferase (FucT-IV). To evaluate the role of sLe(x) in EGFR activation, a knockdown of the FucT-IV gene with small interfering RNA (siRNA) and an inhibitory anti-sLe(x) antibody (KM-93) was used.

RESULTS

We demonstrated a co-localization of sLe(x) with EGFR on NHBE cells using confocal microscopy. Using a blocking antibody for sLe(x) after a mechanical injury, we observed a reduction in EGFR phosphorylation and epithelial repair following injury. FucT-IV demonstrates a temporal expression coordinate with epithelial repair. Down-regulation of FucT-IV expression in NHBE by specific siRNA suppressed sLe(x) expression. The use of FucT-IV siRNA significantly reduced phosphorylation of EGFR and prevented epithelial repair. An immunohistochemical analysis of human normal and asthmatic airways showed a significant reduction in sLe(x) and tyrosine-phosphorylated EGFR (pY(845)-EGFR) in the epithelium of asthmatic subjects compared with that of normal subjects.

CONCLUSION

The present data demonstrate that sLe(x), in association with EGFR, in NHBE is coordinate with repair. This glycosylation is important in modulating EGFR activity to affect the repair of normal primary AEC.

Biological impact of low dose-rate simulated solar particle event radiation in vivo

C57Bl6-lacZ animals were exposed to a range of low dose-rate simulated solar particle event (sSPE) radiation at the NASA-sponsored Research Laboratory (NSRL) at Brookhaven National Laboratory (BNL). Peripheral blood was harvested from animals from 1 to 12 days after total body irradiation (TBI) to quantify the level of circulating reticulocytes (RET) and micronucleated reticulocytes (MN-RET) as an early indicator of radiation-induced genotoxicity. Bone marrow lymphocytes and hippocampal tissues from each animal were collected at 12 days and up to two months, to evaluate dose-dependent late effects after sSPE exposure. Early hematopoietic changes show that the % RET was reduced up to 3 days in response to radiation exposure but recovered at 12 days postirradiation. The % MN-RET in peripheral blood was temporally regulated and dependant on the total accumulated dose. Total chromosome aberrations in lymphocytes increased linearly with dose within a week after radiation and remained significantly higher than the control values at 4 weeks after exposure. The level of aberrations in the irradiated animals returned to control levels by 8 weeks postirradiation. Measurements of chromosome 2 and 8 specific aberrations indicate that, consistent with conventional giemsa-staining methods, the level of aberrations is also not significantly higher than in control animals at 8 weeks postirradiation. The hippocampus was surveyed for differential transcriptional regulation of genes known to be associated with neurogenesis. Our results showed differential expression of neurotrophin and their associated receptor genes within 1 week after sSPE exposure. Progressive changes in the profile of expressed genes known to be involved in neurogenic signaling pathways were dependent on the sSPE dose. Our results to date suggest that radiation-induced changes in the hematopoietic system, i.e., chromosome aberrations in lymphocytes, are transient and do not persist past 4 weeks after radiation. On the other hand, alteration in the profile of genes known to be involved in neurotrophic functions in the hippocampal tissue appears to persist for up to 8 weeks after radiation exposure. Such temporal changes confirm that, although cytogenetic changes after a single dose of low-dose and low-dose-rate protons appear to be transient, the impact of this exposure is sufficient to lead to persistent dynamic changes in neuronal tissues long after the initial radiation exposure.

Intelligent model-based advisory system for the management of ventilated intensive care patients: Hybrid blood gas patient model

Arterial blood gas (ABG) analyses are essential for assessing the acid-base status and guiding the adjustment of mechanical ventilation in critically ill patients. Conventional ABG sampling requires repeated arterial punctures or the insertion of an arterial catheter causing pain, haemorrhage and thrombosis to the patients. Less invasive and non-invasive blood gas analysers, with a technology still in transition, have offered some promise in the recent years. SOPAVent (Simulation of Patients under Artificial Ventilation) is a five compartment blood gas model which captures the basic features of respiratory physiology and gas exchange in the human lungs. It uses ventilator settings and routinely monitored physiological parameters as inputs to produce steady-state estimates of the patient's ABG. This paper overviews the original SOPAVent model and presents an improved data-driven hybrid model that is patient-specific and gives continuous and totally non-invasive ABG predictions. The model has been comprehensively tested in simulations and validated using recorded measurements of ABG and ventilator parameters from ICU patients.

Rumen fluid inhibits proliferation and stimulates expression of cyclin-dependent kinase inhibitors 1A and 2A in bovine rumen epithelial cells

It has been known for decades that microbial fermentation within the rumen is critical to postnatal rumen epithelial growth and maturation in ruminants, but the underlying mechanism is largely unknown. In this study, we determined the effect of rumen fluid, which should contain all products from rumen fermentation, on growth of rumen epithelial cells in vitro. Addition of 10% rumen fluid from cows to the culture medium inhibited (P < 0.05), whereas addition of 6.5 mM acetate, 2.5 mM propionate, or 1 mM butyrate had no effect (P > 0.1) on, the proliferation of rumen epithelial cells isolated from newborn calves. Flow cytometric assays showed that 10% rumen fluid inhibited (P < 0.05) the transition of rumen epithelial cells from the G1 phase to the S phase during the cell cycle. Real-time RT-PCR analyses of mRNA for key cell cycle regulators indicated that 10% rumen fluid did not change (P > 0.1) the expression of cyclin D1, D2, D3, E1, or E2 mRNA or that of cyclin-dependent kinase inhibitor 1B or 2B mRNA, but increased (P < 0.05) the expression of cyclin-dependent kinase inhibitors 1A and 2A mRNA in rumen epithelial cells. These mRNA data support the possibility that rumen fluid inhibits proliferation of rumen epithelial cells in vitro by increasing the expression of cyclin-dependent kinase inhibitors 1A and 2A. The result that rumen fluid inhibits proliferation of bovine rumen epithelial cells in culture indicates that rumen fermentation does not stimulate the postnatal rumen epithelial growth in cattle by directly stimulating proliferation of rumen epithelial cells.

In situ generation of sodium alginate/hydroxyapatite nanocomposite beads as drug-controlled release matrices

In order to find a new way to slow down the release of drugs and to solve the burst release problem of drugs from traditionally used hydrogel matrices, a series of novel pH-sensitive sodium alginate/hydroxyapatite (SA/HA) nanocomposite beads was prepared by the in situ generation of HA micro-particles in the beads during the sol-gel transition process of SA. The SA/HA nanocomposites were characterized by Fourier transform IR spectroscopy, X-ray fluorescence spectrometry, scanning electron microscopy and field emission SEM in order to reveal their composition and surface morphology as well as the role that the in situ generated HA micro-particles play. The factors influencing the swelling behavior, drug loading and controlled release behavior of the SA/HA nanocomposite beads were also investigated using diclofenac sodium (DS) as the model drug. The HA micro-particles act as inorganic crosslinkers in the nanocomposites, which could contract and restrict the movability of the SA polymer chains, and then change the surface morphology and decrease the swell ratio. Meanwhile, the entrapment efficiency of DS was improved, and the burst release of DS was overcome. The factors (including concentration of Ca(2+), reaction time and temperature) affecting the growth of HA micro-particles have a clear influence on the entrapment efficiency and release rate of DS. In this work, the nanocomposite beads prepared under optimum condition could prolong the release of DS for 8h more compared with the pristine SA hydrogel beads.

Molecular characterization of the DDX3Y gene and its homologs in cattle

DDX3Y (also known as DBY) is a member of the DEAD box protein family, which is involved in ATP-dependent RNA unwinding, needed in a variety of cellular processes including splicing, ribosome biogenesis and RNA degradation. In the human, DDX3Y is located in the AZFa interval in the Y chromosome. Deletion of the AZFa region has been shown to disrupt spermatogenesis, causing subfertility and infertility in otherwise healthy men. Here, we report the characterization of the bovine (b) DDX3Y gene and its homologs DDX3X and PL10. We found 2 transcripts for the bDDX3Y (bDDX3Y-L and -S), which correspond to the long and short transcripts of the human DDX3Y and mouse Ddx3y gene. The 2 transcripts are identical except for a 3-bp (AGT) insertion at the position of nt 2025 and an expanded 3'UTR (nt 2155-2769) in bDDX3Y-L. The bDDX3Y-S encodes a peptide of 660 amino acids (aa), while the bDDX3Y-L encodes a peptide of 661 aa as the result of an additional serine (S) insertion at the position of aa 634. Both bDDX3Y isoforms contain the conserved DEAD-box motif. The bDDX3Y is composed of 17 exons. The homologous gene on the X chromosome, bDDX3X, is highly conserved to the Y-copy at mRNA (83%) and protein (88%) levels as well as in the genomic structure. The autosomal copy, bPL10, mapped on BTA15, is a processed pseudogene with a similarity of 88.1% to bDDX3Y and 93.7% to bDDX3X mRNA, suggesting that PL10 is a retroposon of DDX3X. RT-PCR analyses showed that bDDX3Y-L, -S, bDDX3X and bPL10 were all widely expressed with predominant expression in testis and brain. Testicular section in situ hybridization revealed that sense and anti-sense RNAs of bDDX3Y-L, -S, and bDDX3X were expressed in interstitial cells. These results together with the finding that the pseudogene bPL10 is transcriptionally active in this study provide a basis for further investigating the DDX3 gene function in spermatogenesis, male fertility and gene evolution in mammals.

Molecular characterization and experimental host range of an isolate of Wissadula golden mosaic St. Thomas virus

Partial genome segments of a begomovirus were previously amplified from Wissadula amplissima exhibiting yellow-mosaic and leaf-curl symptoms in the parish of St. Thomas, Jamaica and this isolate assigned to a tentative begomovirus species, Wissadula golden mosaic St. Thomas virus. To clone the complete genome of this isolate of Wissadula golden mosaic St. Thomas virus, abutting primers were designed to PCR amplify its full-length DNA-A and DNA-B components. Sequence analysis of the complete begomovirus genome obtained, confirmed that it belongs to a distinct begomovirus species and this isolate was named Wissadula golden mosaic St. Thomas virus-[Jamaica:Albion:2005] (WGMSTV-[JM:Alb:05]). The genome of WGMSTV-[JM:Alb:05] is organized similar to that of other bipartite Western Hemisphere begomoviruses. Phylogenetic analyses placed the genome components of WGMSTV-[JM:Alb:05] in the Abutilon mosaic virus clade and showed that the DNA-A component is most closely related to four begomovirus species from Cuba, Tobacco leaf curl Cuba virus, Tobacco leaf rugose virus, Tobacco mottle leaf curl virus, and Tomato yellow distortion leaf virus. The putative Rep-binding-site motif in the common region of WGMSTV-[JM:Alb:05] was observed to be identical to that of Chino del tomate virus-Tomato [Mexico:Sinaloa:1983], Sida yellow mosaic Yucatan virus-[Mexico:Yucatan:2005], and Tomato leaf curl Sinaloa virus-[Nicaragua:Santa Lucia], suggesting that WGMSTV-[JM:Alb:05] is capable of forming viable pseudo-recombinants with these begomoviruses, but not with other members of the Abutilon mosaic virus clade. Biolistic inoculation of test plant species with partial dimers of the WGMSTV-[JM:Alb:05] DNA-A and DNA-B components showed that the virus was infectious to Nicotiana benthamiana and W. amplissima and the cultivated species Phaseolus vulgaris (kidney bean) and Lycopersicon esculentum (tomato). Infected W. amplissima plants developed symptoms similar to symptoms observed under field conditions, confirming that this virus is a causal agent of Wissadula yellow mosaic disease in W. amplissima.

An intron 1 polymorphism in the cholecystokinin-A receptor gene associated with schizophrenia in males

OBJECTIVE

To identify whether a genetic variation (rs1800857; IVS1-5T>C) in the neuropeptide cholecystokinin-A receptor (CCKAR) gene is a risk factor in the pathogenesis of schizophrenia.

METHOD

The variation was analysed in a case-control design comprising 508 patients with schizophrenia and 1619 control subjects. A possible functional impact of this variant on CCKAR protein synthesis through alterations in splicing was analysed in an exon-trapping assay.

RESULTS

In males only, the risk variant, IVS1-5C, was associated with a significantly increased risk of schizophrenia. Carrying one risk allele was associated with an increased risk of 1.74 (Odds Ratio, OR) and homozygosity (CC) was associated with an OR of 3.19. The variation had no impact on protein synthesis of CCKAR.

CONCLUSION

This is the first report associating the CCKAR gene variant with schizophrenia specifically in men. Our study strengthens the conclusion that a CCKAR dysfunction could be involved in the aetiology of schizophrenia.

16alpha-Bromoepiandrosterone (HE2000) limits non-productive inflammation and stimulates immunity in lungs

16alpha-Bromoepiandrosterone (HE2000) is a synthetic steroid that limits non-productive inflammation, enhances protective immunity and improves survival in clinical studies of patients with human immunodeficiency virus (HIV), malaria and tuberculosis infections. We now show that HE2000 decreased nitric oxide production by lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Treatment with HE2000 also reduced non-productive inflammation associated with carrageenan-induced pleurisy and LPS-induced lung injury in mice. In the hapten-carrier reporter antigen popliteal lymph node assay, HE2000 increased absolute numbers of lymphocytes, antigen-presenting cells, hapten-specific immunoglobulin (Ig)M antibody-forming cells and shifted the interferon (IFN)-gamma/interleukin (IL)-4 balance towards IFN-gamma production. In the cystic fibrosis transmembrane conductance regulator (CFTR(-/-)) mouse model of acute Pseudomonas aeruginosa infection, treatment with HE2000 consistently reduced bacterial burden in lungs. All HE2000 effects were dose-dependent. In H1N1 infection in mice, HE2000 was safe but not effective as a monotherapy, as treatment did not effect survival. HE2000 reduced mortality related to excessive inflammation and opportunistic lung infections in animals and patients, and this might extend to those with H1N1 influenza infection.

Identification and characterization of the bovine G protein-coupled receptor GPR41 and GPR43 genes

Volatile fatty acids (VFA), including acetate, propionate, and butyrate, are not only a primary source of energy, but also regulate rumen development, insulin and glucagon secretion, and other physiological processes in cattle and sheep. The mechanism underlying the regulatory effects of VFA is unknown. Recent "reverse pharmacology" studies identified human G protein-coupled receptors GPR41 and GPR43 as receptors for short-chain fatty acids. It is possible that proteins similar to human GPR41 and GPR43 mediate the regulatory effects of VFA in cattle. In this study, we determined first, whether the bovine genome contains genes similar to the human GPR41 and GPR43 genes; second, whether and where these genes are expressed in cattle; and third, if the proteins encoded by these genes can be activated by acetate, propionate, and butyrate. A search of GenBank revealed bovine genomic sequences and expressed sequence tags highly similar to the human GPR41 and GPR43 DNA and cDNA sequences. The protein-coding and 5' untranslated regions of the bovine GPR41 and GPR43 mRNA were cloned and sequenced from spleen tissue. Based on these sequences, the bovine GPR41 gene contains 3 exons and its transcription is initiated at 2 leader exons, generating 2 GPR41 mRNA variants differing in the 5' untranslated region. The bovine GPR43 gene contains 2 exons and transcription of this gene is initiated from a single start site. The amino acid sequences deduced from the bovine GPR41 and GPR43 mRNA sequences are more than 75% identical to those of the human GPR41 and GPR43 and are predicted to encode 7 transmembrane domains, typical of G protein-coupled receptors. Both bovine GPR41 and GPR43 mRNA were detected in a variety of tissues including rumen and pancreas. In a cell system, interaction of the overexpressed bovine GPR41 or GPR43 protein with acetate, propionate, or butyrate inhibited luciferase reporter expression from a cyclic AMP-responsive promoter, suggesting that the bovine GPR41 and GPR43 proteins couple to Galpha(i/11). In total, these results demonstrate that the bovine genome encodes functional GPR41 and GPR43 genes and suggest that GPR41 and GPR43 may play a role in the regulatory effects of VFA in cattle.

Clinicopathological Variables Associated with Lymph Node Metastasis and Prognostic Factors in pT2 Gastric Cancer

This retrospective study investigated the clinicopathological variables associated with lymph node metastasis and prognosis in 325 patients with pT2 gastric cancer in order to set out a foundation for the surgical management of this condition. Univariate and multivariate analyses identified factors that were predictive of lymph node metastasis. Cox regression analysis evaluated the effect of prognostic factors on survival. Tumour location, maximum tumour diameter, lymphatic invasion and total retrieved lymph nodes (tLN) were revealed as independent factors for lymph node metastasis in pT2a gastric cancer, whereas histological type, lymphatic invasion and tLN were associated with lymph node metastasis in patients with pT2b gastric cancer. Maximum tumour diameter, lymphatic invasion and metastatic lymph node (mLN) ratio, but not tLN, were independent prognostic factors in pT2a cancer. Maximum tumour diameter and mLN ratio, but not tLN, were independent prognostic factors in pT2b cancer. Overall, it is concluded that maximum tumour diameter and mLN ratio are important prognostic factors in pT2 gastric cancer.