Galectin-7 in cardiac allografts in mice: increased expression compared with isografts and localization in infiltrating lymphocytes and vascular endothelial cells

We sought to identify elevated expression of galectin-7, a T-cell-binding protein, in renal allograft recipients undergoing acute rejection episodes. Allografts and isografts were examined immunohistologically and using quantitative Western blot analysis for galectin-7 protein. The expression of galectin-7 in T lymphocytes from draining lymph nodes in the recipient mice was examined using flow cytometry. We observed galectin-7 to gradually increase with time in the allografts to be significantly higher than that in isografts at days 3, 5, and 7 postoperative: 0.85 ± 0.03 versus 0.69 ± 0.05; 1.15 ± 0.11 versus 0.81 ± 0.02; and 2.02 ± 0.12 versus 0.81 ± 0.05 (P < .05). The majority of galectin-7 was located in the infiltrating lymphocytes and vascular endothelial cells. Furthermore, the percentage of CD4+galectin-7+ and CD8+galectin-7+ T cells from draining lymph nodes in the allograft group was higher than that in the isograft group: 28.0 ± 1.0% versus 1.2 ± 0.2%; and 12.4 ± 0.8% versus 0.4 ± 0.1% (P < .01). In conclusion, galectin-7 relates to acute allograft rejection and T-cell responses possibly as an accelerant.

Effect of overexpression of human aldehyde dehydrogenase 2 in LLC-PK1 cells on glyceryl trinitrate biotransformation and cGMP accumulation

BACKGROUND AND PURPOSE

Recent studies suggest a primary role for aldehyde dehydrogenase 2 (ALDH2) in mediating the biotransformation of organic nitrates, such as glyceryl trinitrate (GTN), to the proximal activator of soluble guanylyl cyclase (sGC), resulting in increased cGMP accumulation and vasodilation. Our objective was to assess the role of ALDH2 in organic nitrate action using a cell culture model.

EXPERIMENTAL APPROACH

Porcine renal epithelial (LLC-PK1) cells possess an intact NO-sGC-cGMP signaling system, and can be used as a biochemical model of organic nitrate action. We used a pcDNA3.1-human ALDH2 expression vector to establish a stably transfected cell line (PK1(ALDH2)) that overexpressed ALDH2, or small interfering RNA (siRNA) to deplete endogenous ALDH2, and assessed GTN biotransformation and GTN-induced cGMP formation.

KEY RESULTS

ALDH2 activity in the stably transfected cells was approximately sevenfold higher than wild-type cells or cells stably transfected with empty vector (PK1(vector)); and protein expression, as assessed by immunoblot analysis, was markedly increased. In PK1(ALDH2), GTN biotransformation was significantly increased as a result of increased glyceryl-1,2-dinitrate formation compared to wild-type or PK1(vector). However, the incubation of PK1(ALDH2) with 1 or 10 μM GTN did not alter GTN-induced cGMP accumulation compared with wild-type or PK1(vector) cells. Furthermore, siRNA-mediated depletion of ALDH2 had no effect on GTN-induced cGMP formation.

CONCLUSIONS AND IMPLICATIONS

In an intact cell system, neither overexpression nor depletion of ALDH2 affects GTN-induced cGMP formation, indicating that ALDH2 does not mediate the mechanism-based biotransformation of GTN to an activator of sGC.

The efficacy and safety of antiviral therapy with lamivudine to stop the vertical transmission of hepatitis B virus

The purpose of this study was to investigate the efficacy and safety of lamivudine (LAM) in stopping the vertical transmission of hepatitis B virus (HBV). Pregnant women with normal alanine transaminase (ALT) (n = 100) and with abnormal ALT (n = 100) who were positive for hepatitis B e antigen (HBeAg), and with HBV DNA (deoxyribonucleic acid) levels ≥1.0 × 107 copies/ml were enrolled in this study. One hundred volunteers (50 with normal ALT, 50 with abnormal ALT) received 100 mg of LAM daily from the 24th to 32nd week of gestation and the untreated 100 volunteers served as controls. All infants received passive-active immunoprophylaxis. Compared to the control group, the study group got a marked reduction in serum levels (P < 0.001) and high negativity (P < 0.001) of HBV DNA before delivery. They also got normalization in ALT levels as much as controls received general medication (P > 0.05). The prenatal transmission rate in the study group was significantly lower than that of the control group (P < 0.05). There were no differences in incidences of congenital malformation between the two groups (P > 0.05). LAM treatment can effectively and safely stop vertical transmission of HBV and normalize the ALT levels of pregnant women.

ISH-facilitated analysis of meiotic bivalent pairing

Chiasmata constitute one of the cornerstones of sexual reproduction in most eukaryotes. They mediate the reciprocal genetic exchange between homologues and are essential to the proper orientation of the homologous centromeres in meiosis I. As markers of recombination, they offer a cytological means of mapping. Rather than trying to accurately count individual chiasmata, we have examined properties of the mathematical relationship between frequencies of nonadorned disomic configurations in meiosis (ring, rods, and univalents) and the probabilities at which arms of the respective chromosomes are chiasmate (one or more chiasma per arm). Numerical analyses indicated that conventionally analyzed bivalents with nonidentified arms yield statistically biased estimates of chiasma probabilities under a broad range of circumstances. We subsequently analyzed estimators derived from adorned configurations with ISH-marked arms, which were found to be statistically far superior, and with no assumptions concerning interference across the centromere. We applied this methodology in the study of chromosomes 16 and 23 of cotton (Gossypium hirsutum), and estimated their arm lengths in centimorgans. The results for chromosome 23, the only one of the two chromosomes with a documented RFLP map, were consistent with the literature. Similar molecular-meiotic configuration analyses can be used for a wide variety of eukaryotic organisms and purposes: for example, providing far more powerful meiotic comparisons of genomes of chromosomes, and a rapid means of evaluating effects on recombination. Key words : meiotic configurations, chiasma frequencies, in situ hybridization, cotton.

Agrocybe aegerita polysaccharide combined with chemotherapy improves tumor necrosis factor-α and interferon-γ levels in rat esophageal carcinoma

Natural compounds have generated great interest as alternative treatments of diseases like cancer. Here, we investigated the anti-tumor mechanism of one such compound, Agrocybe aegerita polysaccharide, by assessing expression of tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) in rat esophageal carcinoma (EC). EC was induced in healthy Wistar rats by methyl-n-amyl nitrosamine. Subsequently, rats were administered cancer treatment daily for 4 weeks, as follows: the normal control group (the only group not treated with methyl-n-amyl nitrosamine) and model group received only distilled water; the chemotherapy group received tegafur treatment; and the combination group received tegafur combined with A. aegerita polysaccharide. In normal and combination groups, body weight increased gradually after each week of treatment (P < 0.05), while body weights did not change in model and chemotherapy groups. Using enzyme linked immunosorbent assay, we found serum TNF-α was lower in the combination group (31.56 ± 7.20 pg/L) than either the model (46.24 ± 8.52 pg/L) or chemotherapy (52.39 ± 9.16 pg/L) group, and, while higher, was more similar to the normal controls (25.08 ± 2.93 pg/L; P < 0.05), a finding that was confirmed by the immunohistochemistry of esophageal samples. In contrast, serum IFN-γ was higher in the combination group (97.20 ± 10.92 pg/L) than in either the model (76.11 ± 11.92 pg/L) or chemotherapy (76.04 ± 9.85 pg/L) group, but lower than in the normal group (117.56 ± 10.88; P < 0.05), also confirmed by immunohistochemistry. Therefore, Agrocybe aegerita polysaccharide, when combined with chemotherapy, can regulate immune function in EC, potentially by modulating cytokine activity, specifically downregulation of TNF-α and upregulation of IFN-γ.

Saponins isolated from Asparagus induce apoptosis in human hepatoma cell line HepG2 through a mitochondrial-mediated pathway

OBJECTIVE

Many scientific studies have shown that Asparagus officinalis has an antitumour effect and enhances human immunity, but the active components and the antitumour mechanisms are unclear. We investigated the effects of saponins isolated from Asparagus on proliferation and apoptosis in the human hepatoma cell line HepG2.

METHODS

HepG2 cells were treated with varying concentrations of Asparagus saponins at various times. Using mtt and flow cytometry assays, we evaluated the effects of Asparagus saponins on the growth and apoptosis of HepG2 cells. Transmission electron microscopy was used to observe the morphology of cell apoptosis. Confocal laser scanning microscopy was used to analyze intracellular calcium ion concentration, mitochondrial permeability transition pore (mptp), and mitochondrial membrane potential (mmp). Spectrophotometry was applied to quantify the activity of caspase-9 and caspase-3. Flow cytometry was used to investigate the levels of reactive oxygen species (ros) and pH, and the expressions of Bcl2, Bax, CytC, and caspase-3, in HepG2 cells.

RESULTS

Asparagus saponins inhibited the growth of HepG2 cells in a dose-dependent manner. The median inhibitory concentration (IC(50)) was 101.15 mg/L at 72 hours. The apoptosis morphology at 72 hours of treatment was obvious, showing cell protuberance, concentrated cytoplasm, and apoptotic bodies. The apoptotic rates at 72 hours were 30.9%, 51.7%, and 62.1% (for saponin concentrations of 50 mg/L, 100 mg/L, 200 mg/L). Treatment with Asparagus saponins for 24 hours increased the intracellular level of ros and Ca(2+), lowered the pH, activated intracellular mptp, and decreased mmp in a dose-dependent manner. Treatment also increased the activity of caspase-9 and caspase-3, downregulated the expression of Bcl2, upregulated the expression of Bax, and induced release of CytC and activation of caspase-3.

CONCLUSIONS

Asparagus saponins induce apoptosis in HepG2 cells through a mitochondrial-mediated and caspase-dependent pathway, suggesting that they may be a potent agent for the treatment of hepatocellular carcinoma.

SU-E-J-162: Development and Application of Internal and External Motion Tracking System

PURPOSE

In this study, we performed the experiment of correlation between internal organ movement and external abdominal surface movement for the mini pig using the developed motion tracking system.

METHODS

The experimental system was consisted with imaging acquisition part and image signal analyzing part. The image acquisition of internal organ was performed with a C-arm fluoroscopy system, and abdominal surface images were acquired with a camera and image acquisition board. The signal processing of the image was conducted using LabVIEW 8.6. The developed system was applied to a mini pig. The information of the internal organ movement was acquired with C-arm fluoroscopy system by tracking the fiducial gold maker pre-implemented into diaphragm, which was used in Cyberknife radiation therapy. The data acquisition of internal organ movement due to respiration and abdominal surface movement was performed under general anesthesia.

RESULTS

The motions of the internal and external markers were well correlated. The correlation coefficients between the AP movement of the external marker and the SI and RL movement of the internal target in the experiment using the mini pig were resulted in 0.903 and 0.905, respectively.

CONCLUSIONS

It is confirmed that high correlations between the movements of external marker and the targetassigned in diaphragm in the experimental case for the mini pig were existed. Therefore, it is possible to predict the locations of internal target from the movement of the external marker. These results show the possibility to use the DTTRT (Dynamic Tumor Tracking Radiation Therapy) system of Korea Institute of Radiological and Medical Science (KIRAMS) to clinical application of animals.

Identification and characterization of pig embryo microRNAs by Solexa sequencing

MicroRNAs (miRNAs) are a class of small, non-coding RNAs of approximately 22 nucleotides in length that regulate gene expression by binding to the 3'-untranslated regions of target mRNAs. It is now clear that miRNAs are involved in many biological processes, including proliferation, differentiation and regulation of gene expression during early embryonic development. The miRBase 16.0 (2010) shows that there are 175, 673, 408 and 1048 annotated miRNAs for Caenorhabditis elegans, Mus musculus, Rattus norvegicus and Homo sapiens, respectively. However, there are only 211 miRNAs described for Sus scrofa. In particular, the full set of miRNAs and their expression patterns are still poorly understood in the embryo. Therefore, we combined Solexa sequencing with computational techniques to analyse the sequences and relative expression levels of S. scrofa miRNAs at embryonic day 33 (E33). Of the distinct miRNAs identified, 76 previously known miRNAs and 194 candidate miRNAs were identified in head, and 77 known miRNAs and 130 predicted candidate miRNAs were identified in organ region. Furthermore, we performed additional investigation for identifying the potential target mRNAs using PicTar and TargetScan. Concurrent function analysis suggested that highly expressed miRNAs are mostly involved in the development of nerves, cerebrum, muscle and organs. Our results provide useful information for the investigation into embryonic miRNAs of pig and provide a valuable resource for investigators interested in the regulation of embryonic development in pigs and other animals.

The impact of prior radiotherapy on fatal complications after self-expandable metallic stents (SEMS) for malignant dysphagia due to esophageal carcinoma

The esophageal stent has been demonstrated to serve as a safe and effective palliative treatment for advanced inoperable esophageal carcinoma. However, the safety of esophageal stents in patients with prior radiotherapy (RT) remains debated. This article aims to investigate the impact of prior RT on the incidence of fatal complications after self-expandable metallic stents for palliation of malignant dysphagia because of esophageal carcinoma. Between January 2007 and July 2010, 93 patients with malignant dysphagia because of esophageal carcinoma underwent placement of self-expandable metallic stents in our hospital. Patients were retrospectively separated into two groups: patients with RT before stent placement (RT group, n=57) and patients with no treatment before stent placement (no RT group, n=35).The median survival after stent placement was 77 days (7-842 days) in the RT group and 246 days (15-878 days) in the no RT group. Improvement in dysphagia score was similar in both groups. The fatal complications included fatal gastrointestinal hemorrhage and uncontrolled pneumonia. The incidence of fatal gastrointestinal hemorrhage and uncontrolled pneumonia were 28.1% and 5.7% (P=0.009), 28.1% and 5.7% (P=0.009), respectively. Logistic regression analysis showed a significant interaction between prior RT and fatal gastrointestinal hemorrhage (relative risk 7.82, 95% confidence interval 1.54-39.61; P=0.013). Mortality of massive hemorrhage was 5.7% (2/35), 0% (0/4), 12.5% (3/24), and 44.8% (13/29), respectively, in patients who received 0, 1Gy∼49Gy, 50Gy∼60Gy, and >60Gy (χ(2) =17.761; P=0.000). Logistic regression analysis disclosed prior RT did not significantly increase the risk of uncontrolled pneumonia (relative risk 1.47, 95% confidence interval 0.21-10.12; P=0.697).

Socioeconomic status and children with intellectual disability in China

BACKGROUND

Intellectual disability (ID) accounts for 70% of all disabilities among children in China's Second National Sampling Survey on Disability. Although studies have shown a relationship between social class and ID in children, none have investigated the association of socioeconomic variables in Chinese children with mild or severe ID.

METHODS

Data for children aged 0-6 years with and without ID were abstracted from the Second National Sampling Survey on Disability in China, conducted in 2006. Crude odds ratios showed the effect of sociodemographic factors on mild and severe ID. Adjusted odds ratios (OR(a) ) (95% confidence intervals) estimated the independent effects of these factors.

RESULTS

For both mild and severe ID, risk of having ID increased with male sex, birth to a woman aged 35 years and older, lower maternal education, mother's older age at delivery, lower income and rural residence. After age, gender and parent disability were controlled, mothers aged 35 years and older were more likely to have a child with ID: mild ID, OR(a) 1.47 (1.15-1.88); severe ID, OR(a) 1.32 (1.00-1.73). There was an approximate increasing monotonic risk of severe ID with increasing socioeconomic disadvantage: lowest income, OR(a) 3.00 (2.19-4.12); low income, OR(a) 2.28 (1.63-3.19); lower middle income, OR(a) 1.72 (1.27-2.33); middle income, OR(a) 1.73 (1.28-2.36).

CONCLUSIONS

There is a significant relationship between sociodemographic factors and ID. Similar patterns were found for both mild and severe ID. Recommendations are given for preventing ID in Chinese children.

Metabolite detection of pancreatic carcinoma by in vivo proton MR spectroscopy at 3T: initial results

PURPOSE

The authors sought to identify metabolic features of pancreatic carcinoma by in vivo proton magnetic resonance (MR) spectroscopy at 3 Tesla.

MATERIALS AND METHODS

Forty healthy volunteers and 40 patients with pancreatic carcinoma confirmed by histopathology underwent T2-weighted imaging for localisation of the single voxel. Respiration-triggered (1)H MR spectroscopy was used to detect metabolites in normal pancreas and cancerous tissue. All spectral data were processed with SAGE software. Unsuppressed water at 4.7 ppm was used as an internal reference to determine metabolite concentrations. Each ratio among the different peak areas was statistically evaluated between normal pancreas and pancreatic carcinoma.

RESULTS

The following five groups of spectra were detected: unsaturated fatty acids (-CH = CH-) at 5.4 ppm; residual water at 4.7 ppm; choline metabolites at 3.2 ppm; unsaturated fatty acids (-CH2-CH = CH-) or a combination of N-acetylaspartate (NAA), N-acetylaspartylglutamate (NAAG), glutamine, glutamate, macromolecules and unsaturated fatty acids (-CH2-CH = CH-) at 2.0 ppm and lipids at 1.3 ppm. Ratio of lipids to unsuppressed water in normal pancreas was statistically greater than that in pancreatic cancer (p=0.004). Ratio of choline to unsuppressed water in normal pancreas was statistically greater than that in pancreatic cancer (p=0.0001). Ratio of fatty acids (-CH = CH-) to lipids in normal pancreas was statistically lower than that in pancreatic cancer (p=0.006).

CONCLUSIONS

Compared with normal pancreas, pancreatic carcinoma has a higher ratio of fatty acids (-CH = CH-) to lipids and lower ratios of lipids to unsuppressed water and choline to unsuppressed water at 3T.

The incidence and risk factors of invasive fungal infection after haploidentical haematopoietic stem cell transplantation without in vitro T-cell depletion

In recent years, we have successfully established a novel method of haploidentical haematopoietic stem cell transplantation (HSCT) without in vitro T-cell depletion. This study was aimed at analysing the incidence and risk factors of invasive fungal infection (IFI) with this transplantation method. The study comprised 291 patients who had undergone haploidentical HSCT from 1 January 2007 to 31 December 2008. IFI was diagnosed according to the European Organization for Research and Treatment of Cancer/Mycoses Study Group 2002 criteria, and only proven or probable cases of IFI were regarded as true cases. A total of 39 patients were documented as having IFI, including four proven cases and 35 probable cases. The median time of diagnosis was 26 days (range: 6-405 days) after transplantation. The cumulative incidence rates of IFI at 40 days, 1 year, 2 years and 3 years after transplantation were 8.25%, 13.1%, 13.4% and 13.4%, respectively. Multivariate analysis identified platelet engraftment time (>17 days) (p 0.027; hazard ratio (HR) 2.432; 95% CI 1.105-5.355), a high risk of underlying disease (p 0.001; HR 2.916; 95% CI 1.515-5.611) and grade III-IV acute graft-versus-host disease (p 0.019; HR 2.407; 95% CI 1.154-5.022) as risk factors for IFI. The incidence rates of IFI in patients with no, one, two or three risk factors at 3 years after transplantation were 4.48%, 7.86%, 29.6% and 23.1%, respectively. In conclusion, IFI is an important complication following haploidentical HSCT without in vitro T-cell depletion.

Two novel HLA-A alleles: HLA-A*31:01:09 and HLA-A*33:30

The HLA-A*31:01:09 differs from the closest allele HLAA*31:01:02 by a C to T silent substitution at position 447 in exon 3. The HLA-A*33:30 differs from the closest allele HLA-A*33:03:01 by a single nucleotide substitution at position 453 in exon 3, leading to a change of Arg 131 Cys.

The expression of CXCR4 and its relationship with matrix metalloproteinase-9/vascular endothelial growth factor in esophageal squamous cell cancer

Esophageal cancer (EC) is a highly aggressive neoplasm with poor prognosis. The main reason for this disappointing outcome is the strong behavior of esophageal cancer cell's invasion and metastasis. CXC chemokine receptor 4 (CXCR4) was found to be expressed in many tumors and significantly correlated with invasion, angiogenesis, metastasis, and prognosis. In the present study, we investigated the expressions of CXCR4, matrix metalloproteinase-9 (MMP-9), and vascular endothelial growth factor (VEGF) in esophageal squamous cell cancer (ESCC) and analyzed the relationship among the three proteins. Sections of paraffin-embedded tissues were obtained from 127 patients with ESCC undergoing esophagectomy at Zhongshan Hospital, Fudan University in 2005. The CXCR4, MMP-9, and VEGF expressions in EC tissues were evaluated according to the immunohistochemical staining area and intensity. The correlations between patients' prognosis and covariates were analyzed by Kaplan--Meier method (univariate analysis) and Cox regression (multivariate analysis). The overall expression rate of CXCR4, MMP-9, and VEGF was 88.2%, 93.7%, and 79.5%, respectively. CXCR4 expression was significantly associated with tumor grade, tumor size, tumor depth, regional lymph node metastasis, and tumor, node, metastasis (TNM) stage (P < 0.05). MMP-9 expression was significantly associated with age and tumor grade (P < 0.05). VEGF expression was significantly associated with tumor grade, tumor depth, and TNM stage (P < 0.05). CXCR4 expression was positively correlated with MMP-9 expression (P < 0.01, r= 0.365) and VEGF expression (P < 0.01, r= 0.380). However, there was no significant correlation between MMP-9 and VEGF expression (P > 0.05). In univariate analysis, CXCR4 expression, tumor size, tumor depth, lymph node metastasis, and TNM stage were correlated with patients' prognosis (P < 0.05); in multivariate analysis, tumor size and lymph node metastasis were the independent factors of poor prognosis. CXCR4 was highly expressed in ESCC and correlated with MMP-9, VEGF, clinicopathological features and prognosis. We speculated CXCR4 play an important role during the progression of this disease and there might be some regulatory mechanism existing between CXCR4 and MMP-9/VEGF in ESCC.

Celecoxib inhibits β-catenin-dependent survival of the human osteosarcoma MG-63 cell line

Cyclo-oxygenase (COX)-2 inhibitors may exert antitumour effects through COX-2-independent mechanisms. This study investigated the effects of the COX-2 inhibitor celecoxib on the viability of the human osteosarcoma MG-63 cell line and its β-catenin signalling pathway. Cell viability and apoptosis were examined in celecoxib-treated cells or after β-catenin knockdown in vitro. Analyses were performed to detect glycogen synthase kinase (GSK)-3β, phosphorylated GSK-3β, β-catenin, c-Myc and cyclin D1 proteins, and mRNA levels of β-catenin, c-Myc and CCND1 (encoding cyclin D1). β-Catenin was shown to be required for MG63 cell survival and celecoxib exerted an inhibitory effect on the viability of cultured MG-63 cells in a time- and dose-dependent manner. β-Catenin protein decreased in the cytosol and nucleus following celecoxib treatment (from 6 h after initiation of treatment onwards; lowest protein levels were reached at > 72 h). Significant reductions in β-catenin, c-Myc and CCND1 mRNA were observed. Celecoxib inhibited MG-63 cell viability, possibly by activating GSK-3β and inhibiting β-catenin-dependent gene transcription, suggesting a role for celecoxib in osteosarcoma treatment.

Glycine and a glycine dehydrogenase (GLDC) SNP as citalopram/escitalopram response biomarkers in depression: pharmacometabolomics-informed pharmacogenomics

Major depressive disorder (MDD) is a common psychiatric disease. Selective serotonin reuptake inhibitors (SSRIs) are an important class of drugs used in the treatment of MDD. However, many patients do not respond adequately to SSRI therapy. We used a pharmacometabolomics-informed pharmacogenomic research strategy to identify citalopram/escitalopram treatment outcome biomarkers. Metabolomic assay of plasma samples from 20 escitalopram remitters and 20 nonremitters showed that glycine was negatively associated with treatment outcome (P = 0.0054). This observation was pursued by genotyping tag single-nucleotide polymorphisms (SNPs) for genes encoding glycine synthesis and degradation enzymes, using 529 DNA samples from SSRI-treated MDD patients. The rs10975641 SNP in the glycine dehydrogenase (GLDC) gene was associated with treatment outcome phenotypes. Genotyping for rs10975641 was carried out in 1,245 MDD patients in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study, and its presence was significant (P = 0.02) in DNA taken from these patients. These results highlight a possible role for glycine in SSRI response and illustrate the use of pharmacometabolomics to "inform" pharmacogenomics.

Multivariate models to detect genomic signatures for a class of drugs: application to thiopurines pharmacogenomics

Often, analysis for pharmacogenomic studies involving multiple drugs from the same class is completed by analyzing each drug individually for association with genomic variation. However, by completing the analysis of each drug individually, we may be losing valuable information. When studying multiple drugs from the same drug class, one may wish to determine genomic variation that explains the difference in response between individuals for the drug class, as opposed to each individual drug. Therefore, we have developed a multivariate model to assess whether genomic variation impacts a class of drugs. In addition to determine genomic effects that are similar for the drugs, we will also be able to determine genomic effects that differ between the drugs (that is, interaction). We will illustrate the utility of this multivariate model for cytotoxicity and genomic data collected on the Coriell Human Variation Panel for the class of anti-purine metabolites (6-mercaptopurine and 6-thioguanine).

Catechol O-methyltransferase pharmacogenomics and selective serotonin reuptake inhibitor response

We applied a systematic pharmacogenetic approach to investigate the role of genetic variation in the gene encoding catechol O-methyltransferase (COMT) in individual variation in selective serotonin reuptake inhibitor (SSRI) response among depressed patients. In all, 23 single-nucleotide polymorphisms (SNPs) in COMT were genotyped using DNA from the Sequenced Treatment Alternatives to Relieve Depression (STAR(*)D) study (N=1914). One SNP, rs13306278, located in the distal promoter region of COMT, showed significant association with remission in White non-Hispanic (WNH) subjects (P=0.038). Electromobility shift assay for rs13306278 showed alternation in the ability of the variant sequence to bind nuclear proteins. A replication study was performed using samples from the Mayo Clinic Pharmacogenetics Research Network Citalopram/Escitalopram Pharmacogenomic study (N=422) that demonstrated a similar trend for association. Our findings suggest that novel genetic markers in the COMT distal promoter may influence SSRI response phenotypes.

The role of fibroblast Tiam1 in tumor cell invasion and metastasis

The co-evolution of tumors and their microenvironment involves bidirectional communication between tumor cells and tumor-associated stroma. Various cell types are present in tumor-associated stroma, of which fibroblasts are the most abundant. The Rac exchange factor Tiam1 is implicated in multiple signaling pathways in epithelial tumor cells and lack of Tiam1 in tumor cells retards tumor growth in Tiam1 knock-out mouse models. Conversely, tumors arising in Tiam1 knock-out mice have increased invasiveness. We have investigated the role of Tiam1 in tumor-associated fibroblasts as a modulator of tumor cell invasion and metastasis, using retroviral delivery of short hairpin RNA to suppress Tiam1 levels in three different experimental models. In spheroid co-culture of mammary epithelial cells and fibroblasts, Tiam1 silencing in fibroblasts led to increased epithelial cell outgrowth into matrix. In tissue-engineered human skin, Tiam1 silencing in dermal fibroblasts led to increased invasiveness of epidermal keratinocytes with premalignant features. In a model of human breast cancer in mice, co-implantation of mammary fibroblasts inhibited tumor invasion and metastasis, which was reversed by Tiam1 silencing in co-injected fibroblasts. These results suggest that stromal Tiam1 may play a role in modulating the effects of the tumor microenvironment on malignant cell invasion and metastasis. This suggests a set of pathways for further investigation, with implications for future therapeutic targets.