Timothy J Yeatman

Gibbs Cancer Center, Spartanburg, South Carolina, United States

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Publications (177)946.9 Total impact

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    ABSTRACT: Senescence-associated genes (SAGs) are responsible for the senescence-associated secretory phenotype, linked in turn to cellular aging, the aging brain, and the pathogenesis of cancer.
    Journal of Geriatric Oncology 09/2014; · 1.12 Impact Factor
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    ABSTRACT: Based on KRAS testing, the subset of patients with metastatic colorectal cancer (CRC) that could benefit from anti-EGFR therapy can be better delineated. Though KRAS testing has become significantly more prevalent over the last few years, methods for testing remain heterogeneous and discordance has been reported between methods.
    Journal of clinical pathology. 07/2014;
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    ABSTRACT: The epithelial-mesenchymal transition (EMT) is a key developmental program that is often activated during cancer progression and may promote resistance to therapy. An analysis of patients (n = 71) profiled with both gene expression and a global microRNA assessment (∼415 miRs) identified miR-147 as highly anti-correlated with an EMT gene expression signature score and postulated to reverse EMT (MET). miR-147 was transfected into colon cancer cells (HCT116, SW480) as well as lung cancer cells (A-549). The cells were assessed for morphological changes, and evaluated for effects on invasion, motility, and the expression of key EMT markers. Resistance to chemotherapy was evaluated by treating cells with gefitinib, an EGFR inhibitor. The downstream genes regulated by miR-147 were assayed using the Affymetrix GeneChip U133 Plus2.0 platform. miR-147 was identified to: 1. cause MET primarily by increasing the expression of CDH1 and decreasing that of ZEB1; 2. inhibit the invasion and motility of cells; 3. cause G1 arrest by up-regulating p27 and down-regulating cyclin D1. miR-147 also dramatically reversed the native drug resistance of the colon cancer cell line HCT116 to gefitinib. miR-147 significantly repressed Akt phosphorylation, and knockdown of Akt with siRNA induced MET. The morphologic effects of miR-147 on cells appear to be attenuated by TGF-B1, promoting a plastic and reversible transition between MET and EMT. miR-147 induced cancer cells to undergo MET and induced cell cycle arrest, suggesting a potential tumor suppressor role. miR-147 strikingly increased the sensitivity to EGFR inhibitor, gefitinib in cell with native resistance. We conclude that miR-147 might have therapeutic potential given its ability to inhibit proliferation, induce MET, as well as reverse drug sensitivity.
    PLoS ONE 01/2014; 9(1):e84597. · 3.53 Impact Factor
  • Cindy R Timme, Mike Gruidl, Timothy J Yeatman
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    ABSTRACT: The Notch signaling pathway plays a significant role in differentiation, proliferation, apoptosis, and stem cell processes. It is essential for maintenance of the normal colon crypt and has been implicated in colorectal cancer oncogenesis. Downregulation of the Notch pathway through gamma-secretase inhibitors (GSIs) has been shown to induce apoptosis and enhance response to chemotherapy in a variety of malignancies. In this study, we analyzed the effect of MRK-003 (Merck), a potent inhibitor of gamma-secretase, on oxaliplatin-induced apoptosis in colon cancer. Unexpectedly, gamma-secretase inhibition reduced oxaliplatin-induced apoptosis while GSI treatment alone was shown to have no effect on growth or apoptosis. We determined that the underlying mechanism of action involved an increase in protein levels of the anti-apoptotic Bcl-2 family members Mcl-1 and/or Bcl-xL which resulted in reduced Bax and Bak activation. Blocking of Mcl-1 and/or Bcl-xL through siRNA or the small molecule inhibitor obatoclax restored the apoptotic potential of cells treated with both oxaliplatin and MRK-003. Moreover, obatoclax synergized with MRK-003 alone to induce apoptosis. Our findings warrant caution when treating colon cancer with the combination of GSIs and chemotherapy, whereas other drug combinations, such as GSIs plus obatoclax, should be explored.
    Apoptosis 07/2013; · 4.07 Impact Factor
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    ABSTRACT: Alpha-fetoprotein (AFP)-secreting hepatocellular carcinomas (HCC) represent a genetically distinct subset of tumors often associated with a worse prognosis. However, the molecular mechanisms that underlie these phenotypic differences remain poorly understood. HCC tumor samples from 27 patients were profiled using the Affymetrix 133 Plus 2.0 GeneChips. GeneGO Metacore software was used to identify altered biologic pathways. Expression validation was confirmed by RT-PCR. Manipulation of miR-675 by overexpression and antagomir-mediated knockdown was carried out with subsequent evaluation of effects on cell behavior by cell cycle, proliferation, invasion, and growth in soft agar assays. We identified a strong relationship between primary tumor H19 gene expression and elevated serum AFP. H19 has recently been identified to encode microRNA-675 (miR-675), and we confirmed the relationship in an independent sample of patients. Pathway analyses of the effect of miR-675 overexpression in hepatoma cells revealed a predominant upregulation of cell adhesion and cell cycle initiation pathways. We have demonstrated that miR-675 mediates increases in proliferation and an accumulation of cells with tetraploid DNA content associated with a repression of Rb. We also demonstrated that overexpression of miR-675 alters cellular morphology, reduces invasive potential, and increases anchorage-independent growth capacity. These findings are consistent with a mesenchymal-to-epithelial transition, associated with a reduction in the expression of the key EMT mediator, Twist1. Expression of the miR-675 in hepatocellular carcinoma links a dramatic upregulation of proliferative and growth capacity with inhibition of motility in HCC cells.
    Annals of Surgical Oncology 07/2013; · 4.12 Impact Factor
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    ABSTRACT: The Notch signalling pathway is activated in a variety of malignancies and has been implicated in colorectal cancer progression. One of the first steps in the Notch pathway activation is mediated by γ-secretase, a proteolytic enzyme which produces an activated intracellular Notch (ICN). RO4929097 is a selective inhibitor of γ-secretase. We tested the activity of RO4929097 in patients with metastatic, refractory colorectal cancer. Patients with metastatic colorectal cancer who had received at least two prior lines of systemic chemotherapy were enrolled on the study. Patients were treated with RO4929097 at its recommended phase II dose of 20mg daily, 3 days on and 4 days off continuously. Cycle length was 28 days. Imaging was performed every two cycles. Archival tissue specimens were stained immunohistochemically for components of the notch pathway: Notch1, ICN and the downstream target HES1. Thirty-seven patients were enrolled of whom 33 were evaluable for toxicity and response. Immunohistochemical analysis of archival tissues demonstrated positive staining for the notch receptor as well as intracellular notch and the downstream gene HES1 in the majority of patients. Nevertheless, no objective radiographic responses were observed in this group and only six patients had stable disease as their best response. Median PFS was 1.8 months and median overall survival (OS) was 6.0 months. In this study of RO4929097 in patients with refractory metastatic colorectal cancer, no radiographic responses were seen and time to progression was short, which suggests that RO4929097 at the study dose and schedule has minimal single agent activity in this malignancy.
    European journal of cancer (Oxford, England: 1990) 03/2012; 48(7):997-1003. · 4.12 Impact Factor
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    ABSTRACT: Altered expression of specific microRNAs (miRNA) is known to occur during colorectal carcinogenesis. However, little is known about the genome-wide alterations in miRNA expression during the neoplastic progression of primary colorectal cancers. Using a miRNA array platform, we evaluated the expression of 668 miRNA in primary colonic adenocarcinomas. Biological functions of selected miRNA were evaluated with in vitro invasion assays. RNA was extracted for miRNA analysis from 65 primary colon cancers. We identified a seven-miRNA expression signature that differentiated stage I and stage IV primary colon cancers. We then demonstrated this signature was able to discriminate between stage II and III primary colon cancers. Six differentially expressed miRNA were downregulated in association with the development of metastases, and all 7 miRNA were complementary strand miRNA. We transfected HCT-116, a highly invasive colon cancer cell line, with corresponding downregulated miRNA and demonstrated that overexpression of three miRNA (miR200c*, miR143*, and miR424*) significantly abrogated invasive potential. We have identified a seven-miRNA signature that is associated with metastatic potential in the primary tumor. Forced overexpression of three downregulated miRNA resulted in attenuation of in vitro invasion, suggesting direct tumor suppressive function and further supporting the biological importance of complementary strand miRNA.
    Journal of Gastrointestinal Surgery 02/2012; 16(5):905-12; discussion 912-3. · 2.36 Impact Factor
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    ABSTRACT: The malignancy-risk gene signature is composed of numerous proliferative genes and has been applied to predict breast cancer risk. We hypothesized that the malignancy-risk gene signature has prognostic and predictive value for early-stage non-small cell lung cancer (NSCLC) patients. The ability of the malignancy-risk gene signature to predict overall survival (OS) of early-stage NSCLC patients was tested using a large NSCLC microarray dataset from the Director's Challenge Consortium (n = 442) and two independent NSCLC microarray datasets (n = 117 and 133, for the GSE13213 and GSE14814 datasets, respectively). An overall malignancy-risk score was generated by principal component analysis to determine the prognostic and predictive value of the signature. An interaction model was used to investigate a statistically significant interaction between adjuvant chemotherapy (ACT) and the gene signature. All statistical tests were two-sided. The malignancy-risk gene signature was statistically significantly associated with OS (P < .001) of NSCLC patients. Validation with the two independent datasets demonstrated that the malignancy-risk score had prognostic and predictive values: Of patients who did not receive ACT, those with a low malignancy-risk score had increased OS compared with a high malignancy-risk score (P = .007 and .01 for the GSE13212 and GSE14814 datasets, respectively), indicating a prognostic value; and in the GSE14814 dataset, patients receiving ACT survived longer in the high malignancy-risk score group (P = .03), and a statistically significant interaction between ACT and the signature was observed (P = .02). The malignancy-risk gene signature was associated with OS and was a prognostic and predictive indicator. The malignancy-risk gene signature could be useful to improve prediction of OS and to identify those NSCLC patients who will benefit from ACT.
    CancerSpectrum Knowledge Environment 12/2011; 103(24):1859-70. · 14.07 Impact Factor
  • Timothy J. Yeatman
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    ABSTRACT: Personalized cancer care means that a treatment is delivered to the patient in a very directed fashion. No longer is a one-size fits all approach acceptable. More importantly, the standard approach using non-targeted chemotherapy, treating many patients to help an unknown few, is rapidly falling in disfavor to therapies paired with unique biomarkers. Recent success in targeting patient subpopulations harboring RAF mutations has shown promise for accelerating the drug development process. Moreover, this success suggests the need for increased focus on cancer diagnostics. Biomarker discovery, however, has been a substantial challenge, limited by the availability of a large number of high quality, well-annotated specimens. Here, we describe the development of one of the world’s largest molecular databases of human cancer that will have a wide spectrum of utility in the years to come as the clinical data mature. The database supports a broad initiative in personalized medicine called “Total Cancer Care”. This represents a successful private/public partnership between and an academic medical center, a large network of community hospitals, and a large pharmaceutical company.
    Journal of Medicine and the Person. 12/2011; 9(3).
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    ABSTRACT: Mutational inactivation of adenomatous polyposis coli (APC) is an early event in colorectal cancer (CRC) progression that affects the stability and increases the activity of β-catenin, a mediator of Wnt signaling. Progression of CRC also involves inactivation of signaling via transforming growth factor β and bone morphogenetic protein (BMP), which are tumor suppressors. However, the interactions between these pathways are not clear. We investigated the effects of loss of the transcription factor Smad4 on levels of β-catenin messenger RNA (mRNA) and Wnt signaling. We used microarray analysis to associate levels of Smad4 and β-catenin mRNA in colorectal tumor samples from 250 patients. We performed oligonucleotide-mediated knockdown of Smad4 in human embryonic kidney (HEK293T) and in HCT116 colon cancer cells and transgenically expressed Smad4 in SW480 colon cancer cells. We analyzed adenomas from (APC(Δ1638/+)) and (APC(Δ1638/+)) × (K19Cre(ERT2)Smad4(lox/lox)) mice by using laser capture microdissection. In human CRC samples, reduced levels of Smad4 correlated with increased levels of β-catenin mRNA. In Smad4-depleted cell lines, levels of β-catenin mRNA and Wnt signaling increased. Inhibition of BMP or depletion of Smad4 in HEK293T cells increased binding of RNA polymerase II to the β-catenin gene. Expression of Smad4 in SW480 cells reduced Wnt signaling and levels of β-catenin mRNA. In mice with heterozygous disruption of Apc(APC(Δ1638/+)), Smad4-deficient intestinal adenomas had increased levels of β-catenin mRNA and expression of Wnt target genes compared with adenomas from APC(Δ1638/+) mice that expressed Smad4. Transcription of β-catenin is inhibited by BMP signaling to Smad4. These findings provide important information about the interaction among transforming growth factor β, BMP, and Wnt signaling pathways in progression of CRC.
    Gastroenterology 11/2011; 142(3):562-571.e2. · 12.82 Impact Factor
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    ABSTRACT: Despite continual efforts to develop prognostic and predictive models of colorectal cancer by using clinicopathological and genetic parameters, a clinical test that can discriminate between patients with good or poor outcome after treatment has not been established. Thus, the authors aim to uncover subtypes of colorectal cancer that have distinct biological characteristics associated with prognosis and identify potential biomarkers that best reflect the biological and clinical characteristics of subtypes. Unsupervised hierarchical clustering analysis was applied to gene expression data from 177 patients with colorectal cancer to determine a prognostic gene expression signature. Validation of the signature was sought in two independent patient groups. The association between the signature and prognosis of patients was assessed by Kaplan-Meier plots, log-rank tests and the Cox model. The authors identified a gene signature that was associated with overall survival and disease-free survival in 177 patients and validated in two independent cohorts of 213 patients. In multivariate analysis, the signature was an independent risk factor (HR 3.08; 95% CI 1.33 to 7.14; p=0.008 for overall survival). Subset analysis of patients with AJCC (American Joint Committee on Cancer) stage III cancer revealed that the signature can also identify the patients who have better outcome with adjuvant chemotherapy (CTX). Adjuvant chemotherapy significantly affected disease-free survival in patients in subtype B (3-year rate, 71.2% (CTX) vs 41.9% (no CTX); p=0.004). However, such benefit of adjuvant chemotherapy was not significant for patients in subtype A. The gene signature is an independent predictor of response to chemotherapy and clinical outcome in patients with colorectal cancer.
    Gut 10/2011; 61(9):1291-8. · 10.73 Impact Factor
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    ABSTRACT: The acquisition of a mesenchymal phenotype is a critical step in the metastatic progression of epithelial carcinomas. Adherens junctions (AJs) are required for suppressing this epithelial-mesenchymal transition (EMT) but less is known about the role of tight junctions (TJs) in this process. Here, we investigated the functions of blood vessel epicardial substance (BVES, also known as POPDC1 and POP1), an integral membrane protein that regulates TJ formation. BVES was found to be underexpressed in all stages of human colorectal carcinoma (CRC) and in adenomatous polyps, indicating its suppression occurs early in transformation. Similarly, the majority of CRC cell lines tested exhibited decreased BVES expression and promoter DNA hypermethylation, a modification associated with transcriptional silencing. Treatment with a DNA-demethylating agent restored BVES expression in CRC cell lines, indicating that methylation represses BVES expression. Reexpression of BVES in CRC cell lines promoted an epithelial phenotype, featuring decreased proliferation, migration, invasion, and anchorage-independent growth; impaired growth of an orthotopic xenograft; and blocked metastasis. Conversely, interfering with BVES function by expressing a dominant-negative mutant in human corneal epithelial cells induced mesenchymal features. These biological outcomes were associated with changes in AJ and TJ composition and related signaling. Therefore, BVES prevents EMT, and its epigenetic silencing may be an important step in promoting EMT programs during colon carcinogenesis.
    The Journal of clinical investigation 09/2011; 121(10):4056-69. · 15.39 Impact Factor
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    ABSTRACT: Palladin is a metastasis-associated gene regulating cell motility. The expression of palladin protein in pancreatic neuroendocrine tumors (PET) and carcinomas (PECA) is not known. A tissue microarray (TMA) of well-differentiated (WD) PETs/PECAs (AJCC 2010) and non-neoplastic, histologically normal pancreatic tissue/islets (HNPIs) was immunostained with palladin antibody and quantified using the Allred score. The results were correlated with the presence or absence of liver metastases. The retrospective study included 19 males and 19 females of age 27-79 years (mean 54). Tumor size was 0.9-11.5 cm (mean 3.8). Palladin expression was cytoplasmic and/or membranous. The tumors with high palladin expression were associated with liver metastasis (p<0.0001). All 14 primary PECA with hepatic metastases (MP-PECAs) exhibited palladin expression whereas 14 out of 24 (58%) clinically-localized primary PET (CLP-PETs) expressed palladin (p<0.01) with median Allred scores of 5 (range 3-7) and 2 (range 0-6) respectively (p<0.0001). The mean Allred score for the HNPIs in the MP-PECAs (N=6) was higher (4.2) as compared to that in the CLP-PETs (2.5,N=11) (p=0.23). Palladin may identify primary pancreatic endocrine neoplasms with a propensity to metastasize to the liver.
    Anticancer research 09/2011; 31(9):2957-62. · 1.71 Impact Factor
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    ABSTRACT: The antiapoptotic protein survivin has been demonstrated to play an important role in colorectal carcinogenesis. However it is unclear whether the upregulation of survivin is maintained through progressive stages of disease, or if other apoptosis-related genes are coexpressed and/or repressed. We sought to evaluate survivin expression in colonic neoplasia and identify relationships with additional regulators of apoptosis. Tissue samples from 168 patients with primary colorectal cancer were profiled using the GeneChip Human Genome U133 Plus 2.0 Array (Affymetrix, Santa Clara, CA) and evaluated for survivin expression. Immunohistochemical staining for survivin and a panel of apoptosis-associated proteins were used in 86 patients with tissue microarray (TMA) blocks; scoring was by stain intensity and percentage of positive cells (range, 0-9). Survivin mRNA was upregulated (1.8-fold increase) in primary colon cancers- irrespective of American Joint Committee on Cancer (AJCC) stage- and metastases compared with normal colonic tissue (P < .0001). Survivin staining was positive in 93% of adenocarcinomas (median immunohistochemistry [IHC] score: 2 [range, 1-6]), 100% of adenomas (1 [range,1-2]), and 43% of normal colonic mucosa (1, [range 1-2]) (P = .006). Survivin expression increased with worsening tumor grade (P < .05). In colon cancers, survivin expression positively correlated with the coexpression of PUMA (P < .001), TACE (P = .003), and MCL1 (P = .01), and trended toward an inverse correlation with BAX (P = .058). Survivin expression increases during the normal mucosa-adenoma-carcinoma sequence and is maintained throughout progression of disease, which strengthens its appeal as a therapeutic target. Furthermore, we have demonstrated co-overexpression of several other apoptosis-related genes, which may in turn serve as additional and potentially synergistic therapeutic targets.
    Clinical Colorectal Cancer 09/2011; 10(3):188-93. · 1.80 Impact Factor
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    ABSTRACT: Expression of the tight junction protein claudin-1 is dysregulated in colon tumors and associates with their progression. Up-regulation of claudin-1 reduces expression of E-cadherin. We investigated the mechanisms by which claudin-1 regulates E-cadherin expression and its effects in colon cancer cells. We used gene expression analysis, immunoblotting, and reverse transcription polymerase chain reaction to associate expression of the repressor of transcription Zinc Finger E-box binding homeobox-box1 (ZEB-1) with claudin-1. We analyzed SW480 colon cancer cells that overexpressed claudin-1, or SW620 cells in which claudin-1 expression was repressed, to determine the effects on ZEB-1 and E-cadherin expression, invasive activity, and resistance to anoikis. We studied cells that expressed constitutively active or dominant negative forms of factors in the Wnt or phosphotidylinositol-3-kinase signaling pathways and used pharmacologic inhibitors of these pathways to study their role in claudin-1-dependent regulation of ZEB-1. We used microarray analysis to examine gene expression patterns in 260 colorectal tumor and normal colon samples. Claudin-1 down-regulates E-cadherin expression by up-regulating expression of ZEB-1. Claudin-1 activates Wnt and phosphotidylinositol-3-kinase/Akt signaling. ZEB-1 mediates claudin-1-regulated changes in cell invasion and anoikis. Expression of claudin-1 correlated with that of ZEB-1 in human colon tumor samples. In the progression from normal colonic epithelium to colon adenocarcinoma, levels of E-cadherin decreased, whereas levels of claudin-1 and ZEB-1 increased. Down-regulation of E-cadherin and up-regulation of ZEB-1 in colon tumors were associated with shorter survival times. Claudin-1 up-regulates the repressor ZEB-1 to reduce expression of E-cadherin in colon cancer cells, increasing their invasive activity and reducing anoikis. This pathway is associated with colorectal cancer progression and patient survival.
    Gastroenterology 08/2011; 141(6):2140-53. · 12.82 Impact Factor
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    ABSTRACT: We hypothesized that immune gene-related signatures would predict the presence of unique histological features of lymphoid cell infiltrates in colorectal carcinoma (CRC) that correlate with clinical parameters. Metagene analysis with gene chip technology was performed on 326 CRCs, which were then sorted by low versus high gene scores. Microscopically, CRCs with a high gene score revealed a marked host immune response organized, remarkably, as lymphoid follicles. Proliferation involved both B and T cells. In every case, the presence of CD79a(+) B-cell precursors was identified, suggesting that the lymphoid follicles represent newly formed, ectopic lymph node-like structures. CD21(+) dendritic cells were present within the follicular germinal centers, and CD3(+) T cells were localized mainly in the parafollicular cortex zone surrounding the B-cell area of the follicles. A strong correlation between a 12-chemokine gene subset of the molecular profile and the presence of ectopic lymph node-like structures was associated with better patient survival independent of tumor staging, site location, microsatellite instability or stability, and patient treatment. These findings suggest beneficial, intratumoral immune cell priming and raise the possibility of immunotherapy intervention decisions based on molecular signatures that can identify the presence of tumor-localized, ectopic lymph node-like structures.
    American Journal Of Pathology 07/2011; 179(1):37-45. · 4.60 Impact Factor
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    ABSTRACT: Using gene expression profiling on frozen primary pancreatic endocrine tumors (PETs), we discovered RUNX1T1 as a leading candidate progression gene. This study was designed (1) to validate the differential expression of RUNX1T1 protein on independent test sets of metastatic and nonmetastatic PETs and (2) to determine if RUNX1T1 underexpression in primary tumors was predictive of liver metastases. Immunohistochemical expression of RUNX1T1 protein was quantified using Allred scores on archival metastatic (n = 13) and nonmetastatic (n = 24) primary adult PET tissues using custom-designed tissue microarrays. Wilcoxon rank sum/Fisher exact tests and receiver operating characteristic curves were used in the data analysis. Median RUNX1T1 scores were 2 (2-7) and 6 (3-8) in metastatic versus nonmetastatic primaries (P < 0.0001). Eleven of 13 metastatic and 1 of 24 nonmetastatic primaries exhibited RUNX1T1-scores of 4 or less (P < 0.0001). Low RUNX1T1 expression was highly associated with hepatic metastases (P < 0.0001), whereas conventional histological criteria (Ki-67 index, mitotic rate, necrosis) were weakly associated with metastases (P = 0.08-0.15). Considering RUNX1T1 expression (Allred) score of 4 or less to be predictive, the sensitivity to predict hepatic metastases was 85%, with a specificity of 96%. RUNX1T1 protein is underexpressed in well-differentiated metastatic primary PETs relative to nonmetastatic primaries and emerges as a promising novel biomarker for prediction of liver metastases.
    Pancreas 05/2011; 40(4):627-33. · 2.95 Impact Factor
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    ABSTRACT: The Quantitative Assay Database (QuAD), http://proteome.moffitt.org/QUAD/, facilitates widespread implementation of quantitative mass spectrometry in cancer biology and clinical research through sharing of methods and reagents for monitoring protein expression and modification. Liquid chromatography coupled to multiple reaction monitoring (LC-MRM) mass spectrometry assays are developed using SDS-PAGE fractionated lysates from cancer cell lines. Pathway maps created using GeneGO Metacore provide the biological relationships between proteins and illustrate concepts for multiplexed analysis; each protein can be selected to examine assay development at the protein and peptide levels. The coupling of SDS-PAGE and multiple reaction monitoring mass spectrometry screening has been used to detect 876 peptides from 218 cancer-related proteins in model systems including colon, lung, melanoma, leukemias, and myeloma, which has led to the development of 95 quantitative assays including stable-isotope-labeled peptide standards. Methods are published online and peptide standards are made available to the research community. Protein expression measurements for heat shock proteins, including a comparison with ELISA and monitoring response to the HSP90 inhibitor, 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin (17-DMAG), are used to illustrate the components of the QuAD and its potential utility. This resource enables quantitative assessment of protein components of signaling pathways and biological processes and holds promise for systematic investigation of treatment responses in cancer.
    PROTEOMICS - CLINICAL APPLICATIONS 04/2011; 5(7-8):383-96. · 1.81 Impact Factor
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    ABSTRACT: Claudin-2 is a unique member of the claudin family of transmembrane proteins, as its expression is restricted to the leaky epithelium in vivo and correlates with epithelial leakiness in vitro. However, recent evidence suggests potential functions of claudin-2 that are relevant to neoplastic transformation and growth. In accordance, here we report, on the basis of analysis of mRNA and protein expression using a total of 309 patient samples that claudin-2 expression is significantly increased in colorectal cancer and correlates with cancer progression. We also report similar increases in claudin-2 expression in inflammatory bowel disease-associated colorectal cancer. Most importantly, we demonstrate that the increased claudin-2 expression in colorectal cancer is causally associated with tumor growth as forced claudin-2 expression in colon cancer cells that do not express claudin-2 resulted in significant increases in cell proliferation, anchorage-independent growth and tumor growth in vivo. We further show that the colonic microenvironment regulates claudin-2 expression in a manner dependent on signaling through the EGF receptor (EGFR), a key regulator of colon tumorigenesis. In addition, claudin-2 expression is specifically decreased in the colon of waved-2 mice, naturally deficient in EGFR activation. Furthermore, genetic silencing of claudin-2 expression in Caco-2, a colon cancer cell line, prevents the EGF-induced increase in cell proliferation. Taken together, these results uncover a novel role for claudin-2 in promoting colon cancer, potentially via EGFR transactivation.
    Oncogene 03/2011; 30(29):3234-47. · 8.56 Impact Factor
  • Journal of Surgical Research 02/2011; 165(2):291-292. · 2.02 Impact Factor

Publication Stats

7k Citations
946.90 Total Impact Points

Institutions

  • 2014
    • Gibbs Cancer Center
      Spartanburg, South Carolina, United States
  • 1995–2014
    • Moffitt Cancer Center
      • • Department of Biomedical Informatics
      • • Department of Biostatistics
      • • Department of Molecular Oncology
      Tampa, Florida, United States
  • 2011
    • Binghamton University
      • Department of Bioengineering
      Binghamton, NY, United States
  • 1993–2011
    • University of South Florida
      • • Moffitt Cancer Center
      • • Department of Pathology and Cell Biology
      • • Department of Surgery
      Tampa, Florida, United States
  • 2010
    • New York University
      • Department of Surgery
      New York City, NY, United States
  • 2009
    • National and Kapodistrian University of Athens
      • Division of Surgery V
      Athens, Attiki, Greece
  • 2004–2006
    • Tampa General Hospital
      Tampa, Florida, United States
  • 2002–2005
    • Biomedical Research Institute, Rockville
      Maryland, United States
  • 2001
    • Ochsner
      New Orleans, Louisiana, United States
  • 1993–1995
    • University of Texas MD Anderson Cancer Center
      • Department of General Surgery
      Houston, Texas, United States