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Jessica Wang-Rodriguez

Publications and source records attributed to Jessica Wang-Rodriguez.

14 recordsLinked to original sources
PubMed2006

Two-dimensional transcriptome profiling: identification of messenger RNA isoform signatures in prostate cancer from archived paraffin-embedded cancer specimens.

The expression of specific mRNA isoforms may uniquely reflect the biological state of a cell because it reflects the integrated outcome of both transcriptional and posttranscriptional regulation. In this study, we constructed a splicing array to examine approximately 1,500 mRNA isoforms from a panel of genes previously implicated in prostate cancer and identified a large number of cell type-specific mRNA isoforms. We also developed a novel "two-dimensional" profiling strategy to simultaneously quantify changes in splicing and transcript abundance; the results revealed extensive covariation between transcription and splicing in prostate cancer cells. Taking advantage of the ability of our technology to analyze RNA from formalin-fixed, paraffin-embedded tissues, we derived a specific set of mRNA isoform biomarkers for prostate cancer using independent panels of tissue samples for feature selection and cross-analysis. A number of cancer-specific splicing switch events were further validated by laser capture microdissection. Quantitative changes in transcription/RNA stability and qualitative differences in splicing ratio may thus be combined to characterize tumorigenic programs and signature mRNA isoforms may serve as unique biomarkers for tumor diagnosis and prognosis.

Aged↗
PubMed2006

Profiling alternatively spliced mRNA isoforms for prostate cancer classification.

BACKGROUND: Prostate cancer is one of the leading causes of cancer illness and death among men in the United States and world wide. There is an urgent need to discover good biomarkers for early clinical diagnosis and treatment. Previously, we developed an exon-junction microarray-based assay and profiled 1532 mRNA splice isoforms from 364 potential prostate cancer related genes in 38 prostate tissues. Here, we investigate the advantage of using splice isoforms, which couple transcriptional and splicing regulation, for cancer classification. RESULTS: As many as 464 splice isoforms from more than 200 genes are differentially regulated in tumors at a false discovery rate (FDR) of 0.05. Remarkably, about 30% of genes have isoforms that are called significant but do not exhibit differential expression at the overall mRNA level. A support vector machine (SVM) classifier trained on 128 signature isoforms can correctly predict 92% of the cases, which outperforms the classifier using overall mRNA abundance by about 5%. It is also observed that the classification performance can be improved using multivariate variable selection methods, which take correlation among variables into account. CONCLUSION: These results demonstrate that profiling of splice isoforms is able to provide unique and important information which cannot be detected by conventional microarrays.

Algorithms↗
PubMed2006

EGFR regulates the side population in head and neck squamous cell carcinoma.

OBJECTIVE: To identify the presence of side population (SP) cells in established head and neck squamous carcinoma cell (HNSCC) lines and to determine the role of EGFR in the regulation of the side population of these cells. METHODS: SP cells were identified using flow cytometry analysis by the ability of these cells to extrude the Hoechst 33342 dye via the drug transporter BCRP1/ABCG2. Effect of EGFR on the side population was determined also by difference in Hoechst extrusion and by immunofluorescence. Immunohistochemical staining was performed to show the presence of the BCRP1/ABCG2 transporter and the phosphorylated form of EGFR in HNSCC tissue. RESULTS: SP cells are present in HNSCC cell lines. With the Hoechst 33342 extrusion assay, SP cells were found to comprise an average of 0.69% of the UMSCC10B cells and 0.91% of HN12 cells. Addition of the EGF ligand increased the SP population while inactivation of the EGFR kinase by Iressa significantly decreased SP. CONCLUSION: In established head and neck squamous cell carcinoma cell lines, SP cells were found using methods that determine expression and function of the drug transporter BCRP1/ABCG2. Activation of EGFR, a gene implicated in tumorigenesis in HNSCC leads to increased SP, and conversely, inhibition of EGFR leads to decrease in SP. This finding could help explain the role of EGFR in regulating cancer stem cells and thus tumorigenesis in HNSCC.

ATP Binding Cassette Transporter, Subfamily G, Mem↗
PubMed2006

STI-571 (Gleevec) potentiates the effect of cisplatin in inhibiting the proliferation of head and neck squamous cell carcinoma in vitro.

OBJECTIVE: The objective of this study was to determine whether STI-571 (Gleevec; imatinib mesylate) could sensitize established head and neck squamous cell carcinoma (HNSCC) cell lines to the effects of cisplatin. METHODS: Western blot analysis and immunofluorescence were used to examine the expression of the tyrosine kinases that are known targets of Gleevec, including c-kit, c-Abl, and platelet-derived growth factor receptor, on the cell lines, and immunohistochemistry was performed to determine the expression of these kinases in human HNSCC tissue. Once these targets were confirmed, clonogenic cell survival assays were performed to determine the effect STI-571 had on growth and proliferation when used in combination with cisplatin compared with STI-571 alone or cisplatin alone. Cells were incubated with a range of doses of STI-571 24 hours before the addition of cisplatin. Flow cytometry analysis was performed to determine cell-cycle distribution and to measure apoptosis caused by the various treatments. An annexin V assay was also used to further measure apoptosis. RESULTS: Our results indicate that STI-571 potentiates the effect of cisplatin and leads to a significant decrease in cell proliferation and colony formation compared with cisplatin alone in a dose-dependent fashion. Surprisingly, there was a slight decrease in the level of apoptosis when Gleevec was used in combination with cisplatin compared with cisplatin alone. Gleevec alone resulted in a slight increase in G1 phase of the cell cycle, whereas cisplatin alone resulted in a G2 arrest. The addition of Gleevec to cisplatin resulted in an enhanced S/G2 phase accumulation. Although we did not demonstrate an increase in cisplatin-induced cell death, we postulate that the increased S/G2 arrest resulting from the DNA damage in the presence of Gleevec results in decreased proliferation of HNSCC, resulting in a net decrease in colony formation. CONCLUSIONS: The small molecule inhibitor Gleevec, which targets specific tyrosine kinases that are expressed in HNSCC, can significantly potentiate the antiproliferative effects of cisplatin. Because Gleevec alone has minimal side effects, treatment with the combination treatment of cisplatin and Gleevec may result in increased efficacy of cisplatin in treating this cancer. Additional studies are warranted, keeping in mind that drug combinations may result in unexpected toxicities that are not frequently seen with either drug alone.

Antineoplastic Agents↗
PubMed2006

Gleevec suppresses p63 expression in head and neck squamous cell carcinoma despite p63 activation by DNA-damaging agents.

OBJECTIVES: The objectives of this study were to determine the effects of Gleevec on p63 expression in head and neck squamous cell carcinoma (HNSCC) cell lines and to investigate the role of Gleevec in regulating p63 stabilization under DNA-damaging conditions. METHODS: Immunohistochemical staining was performed to determine p63 expression in HNSCC tissue. Annexin V staining was used to assess the effects of p63 on early apoptosis. Immunoblotting was used to examine the effects of Gleevec on p63 protein levels in HNSCC cell lines in response to DNA damage. Immunofluorescence staining was performed to study the expression pattern of p63 and c-Abl. RESULTS: In HNSCC, p63 protein levels are induced by DNA-damaging agents, including ionizing radiation, doxorubicin, and ultraviolet light. We demonstrate that Gleevec reduces p63/DeltaNp63 expression in a dose-dependent manner in HNSCC and overrides the protein induction by DNA-damaging agents. Overexpression of c-Abl in the absence of Gleevec results in higher levels of p63 than those treated with Gleevec, implicating c-Abl kinase activity as a regulator of p63 protein stability. CONCLUSIONS: Gleevec downregulates p63/DeltaNp63 levels in HNSCC in a dose-dependent manner under both normal and DNA-damaging conditions. This downregulation can be explained by Gleevec's inhibition of c-Abl, which destabilizes p63. Based on our data, treating cancers with high expression of TAp63 with Gleevec may result in the unfavorable inhibition of a tumor suppressor, whereas downregulation of DeltaNp63 would be advantageous. Further development of antibodies that can discriminate between TAp63 and DeltaNp63 will be needed to determine the specific effects of Gleevec on p63 in HNSCC.

Antineoplastic Agents↗
PubMed2005

Constitutive pro- and anti-inflammatory cytokine and growth factor response to exercise in leukocytes.

Leukocytosis following exercise is a well-described phenomenon of stress/inflammatory activation in healthy humans. We hypothesized that, despite this increase in circulating inflammatory cells, exercise would paradoxically induce expression of both pro- and anti-inflammatory cytokines and growth factors within these cells. To test this hypothesis, 11 healthy adult men, 18-30 yr old, performed a 30-min bout of heavy cycling exercise; blood sampling was at baseline, end-exercise, and 60 min into recovery. The percentage of leukocytes positive for intracellular cytokines and growth factors and mean fluorescence intensity was obtained by flow cytometry. Proinflammatory cytokines (IL-1alpha, IL-2, IFN-gamma, and TNF-alpha), a pleiotropic cytokine (IL-6), and anti-inflammatory cytokines and growth factors [IL-4, IL-10, growth hormone (GH), and IGF-I] were examined. Median fluorescence intensity was not affected by exercise; however, we found a number of significant changes (P < 0.05 by mixed linear model and modified t-test) in the numbers of circulating cells positive for particular mediators. The pattern of expression reflected both pro- and anti-inflammatory functions. In T-helper lymphocytes, TNF-alpha, but also IL-6, and IL-4 were significantly increased. In monocytes, both IFN-gamma and IL-4 increased. B-lymphocytes positive for GH and IGF-I increased significantly. GH-positive granulocytes also significantly increased. Collectively, these observations indicate that exercise primes an array of pro- and anti-inflammatory and growth factor expression within circulating leukocytes, perhaps preparing the organism to effectively respond to a variety of stressors imposed by exercise.

Adolescent↗
PubMed2005

Gastrointestinal stromal tumors express ras oncogene: a potential role for diagnosis and treatment.

BACKGROUND: Gastrointestinal stromal tumors (GISTs) constitute the largest category of nonepithelial neoplasms of the gastrointestinal tract. Histologically, they have a spindle cell appearance but stain by immunohistochemistry for the proto-oncogene, c-kit (CD117). There is some evidence that phosphorylation of these receptors leads to a cascade that may activate the ras/mitogen-activated protein kinase pathway, which may, in turn, allow other oncogenes to become active. HYPOTHESIS: Immunohistochemical staining pattern of GISTs will aid in their differentiation from other spindle cell tumors and predict clinical outcome in patients. DESIGN AND SETTING: Retrospective review of patient records and paraffin block specimens of spindle cell tumors. PATIENTS: We have identified 65 patients with spindle cell tumors of the gastrointestinal tract at our institution in the past 10 years. Tumors were diagnosed by their morphology as leiomyomas, leiomyoblastomas, or leiomyosarcomas. MAIN OUTCOME MEASURES: CD117 and ras p21 were stained by immunohistochemistry on formalin-fixed, paraffin-embedded sections of normal and tumor tissues. RESULTS: Of the 65 patients, there were 23 patients diagnosed as having GIST confirmed by CD117 expression and 42 patients without GIST. Gastrointestinal stromal tumor samples of 17 (77%) of 22 patients stained positive for ras protein compared with 0 of 27 patients with leiomyomas (P<.001). CONCLUSIONS: To our knowledge, this study is the first to demonstrate that GISTs stain positive for ras p21. This molecular trait may be a useful diagnostic tool in addition to the c-kit (CD117) to separate GISTs from leiomyomas and leiomyosarcomas. In the future, ras inhibitors may potentially be a therapeutic to treat GISTs.

Adult↗
PubMed2005

Expression of protein tyrosine kinases in head and neck squamous cell carcinomas.

Protein tyrosine kinases (TKs) are overexpressed in many carcinomas and sarcomas. We studied the expression of the following TKs in head and neck squamous cell carcinoma (HNSCC): platelet-derived growth factor receptor (PDGFR), c-kit, epidermal growth factor receptor (EGFR), and a serine-threonine kinase, Akt. Formalin-fixed, paraffin-embedded tumor blocks from 44 consecutive patients with primary HNSCC and 5 specimens of benign pharyngeal and laryngeal mucosa were retrieved for immunohistochemical analysis. Of the specimens, 38 had enough material to stain for all 4 antibodies. The study included 21 pharyngeal (base of tongue, 14; tonsil, 6; soft palate, 1), 16 laryngeal, and 1 floor of the mouth carcinoma. All 4 kinases in the tumor samples were expressed highly (PDGFR, 95%-100%; EGFR, 38%-43%; c-kit, 50%-86%; p-Akt, 57%-81%), with EGFR, c-kit, and p-Akt significantly higher than in benign samples. None of the kinase expressions correlated with disease-free survival. The expression of the kinases raises the possibility of treatment of HNSCC by tyrosine and serine-threonine kinase inhibitors.

Aged↗
PubMed2004

In silico dissection of cell-type-associated patterns of gene expression in prostate cancer.

Prostate tumors are complex entities composed of malignant cells mixed and interacting with nonmalignant cells. However, molecular analyses by standard gene expression profiling are limited because spatial information and nontumor cell types are lost in sample preparation. We scored 88 prostate specimens for relative content of tumor, benign hyperplastic epithelium, stroma, and dilated cystic glands. The proportions of these cell types were then linked in silico to gene expression levels determined by microarray analysis, revealing unique cell-specific profiles. Gene expression differences for malignant and nonmalignant epithelial cells (tumor versus benign hyperplastic epithelium) could be identified without being confounded by contributions from stroma that dominate many samples or sacrificing possible paracrine influences. Cell-specific expression of selected genes was validated by immunohistochemistry and quantitative PCR. The results provide patterns of gene expression for these three lineages with relevance to pathogenetic, diagnostic, and therapeutic considerations.

Gene Expression Profiling↗
PubMed2003

Elevated osteopontin and thrombospondin expression identifies malignant human breast carcinoma but is not indicative of metastatic status.

BACKGROUND: Our previous characterization of a human breast tumor metastasis model identified several candidate metastasis genes. The expression of osteopontin (OPN) correlated with the metastatic phenotype, whereas thrombospondin-1 (TSP-1) and tyrosinase-related protein-1 (TYRP-1) correlated with the nonmetastatic phenotype of independent MDA-MB-435 cell lines implanted orthotopically into athymic mice. The aim of the present study was to examine the cellular distribution of these molecules in human breast tissue and to determine whether the relative expression level of these three genes is associated with human breast tumor metastasis. METHODS: Sixty-eight fresh, frozen specimens including 31 primary infiltrating ductal carcinomas, 22 nodal metastases, 10 fibroadenomas, and five normal breast tissues were evaluated for OPN expression, TSP-1 expression and TYRP-1 expression. Immunohistochemistry was performed to monitor the cellular distribution and to qualitatively assess expression. Quantitative analysis was achieved by enrichment of breast epithelial cells using laser-capture microdissection and subsequent real-time, quantitative PCR. RESULTS: The epithelial components of the breast tissue were the source of OPN and TSP-1 expression, whereas TYRP-1 was present in both the epithelial and stromal components. Both OPN and TSP-1 expression were significantly higher in malignant epithelial sources over normal and benign epithelial sources, but no difference in expression levels was evident between primary tumors with or without metastases, nor between primary and metastatic carcinomas. CONCLUSION: Elevated expression of OPN and TSP-1 may play a role in the pathogenesis of breast cancer. The multiplex analysis of these molecules may enhance our ability to diagnose and/or prognosticate human breast malignancy.

Biomarkers, Tumor↗
PubMed2002

The signaling adapter protein PINCH is up-regulated in the stroma of common cancers, notably at invasive edges.

BACKGROUND: PINCH is an LIM (double zinc finger domain) protein that functions as an adapter at a key convergence point for integrin and growth factor signal transduction. Because no information is available regarding its expression in vivo in human tissues, this study evaluated the distribution and abundance of PINCH in patients with breast, prostate, lung, colon, and skin carcinomas. METHODS: A polyclonal antibody was raised to a purified 6-histidine PINCH fusion protein and used to evaluate 74 cases comprising 33 breast carcinomas (21 ductal carcinomas, 6 lobular carcinomas, 4 ductal carcinomas in situ, 2 lobular carcinomas in situ), 22 prostate carcinomas, 5 colon carcinomas, 6 lung carcinomas (3 adenocarcinomas and 3 squamous carcinomas), and 8 skin carcinomas (4 basal cell carcinomas and 4 squamous cell carcinomas) by immunoperoxidase histochemistry of formalin-fixed, paraffin-embedded tissues. Lysates of frozen tissue from the epithelium of two normal breasts and six breast carcinomas were evaluated by immunoblotting. RESULTS: Immunostaining for PINCH was increased in the cytoplasm of fibroblastoid cells in areas of the tumor-associated stroma in all carcinomatous tissues evaluated. The most intense stromal immunostaining for PINCH was noted at invasive edges, particularly in breast carcinomatous tissue. Immunoblotting of lysates from normal breast and breast carcinomatous tissue confirmed that PINCH protein expression was markedly increased in breast carcinomatous tissues. CONCLUSIONS: PINCH is up-regulated in tumor-associated stromal cells, particularly at invasive edges, and may be a marker for stroma manifesting the ability to facilitate invasion. Because of this and because PINCH functions as a "molecular switch" in signal transduction, PINCH may be a new target for drug discovery aimed at the tumor-associated stroma.

Adaptor Proteins, Signal Transducing↗
PubMed2002

Islet expression of the DNA repair enzyme 8-oxoguanosine DNA glycosylase (Ogg1) in human type 2 diabetes.

BACKGROUND: It has become increasingly clear that beta-cell failure plays a critical role in the pathogenesis of type 2 diabetes. Free-radical mediated beta-cell damage has been intensively studied in type 1 diabetes, but not in human type 2 diabetes. Therefore, we studied the protein expression of the DNA repair enzyme Ogg1 in pancreases from type 2 diabetics. Ogg1 was studied because it is the major enzyme involved in repairing 7,8-dihydro-8-oxoguanosine DNA adducts, a lesion previously observed in a rat model of type 2 diabetes. Moreover, in a gene expression screen, Ogg1 was over-expressed in islets from a human type 2 diabetic. METHODS: Immunofluorescent staining of Ogg1 was performed on pancreatic specimens from healthy controls and patients with diabetes for 2-23 years. The intensity and islet area stained for Ogg1 was evaluated by semi-quantitative scoring. RESULTS: Both the intensity and the area of islet Ogg1 staining were significantly increased in islets from the type 2 diabetic subjects compared to the healthy controls. A correlation between increased Ogg1 fluorescent staining intensity and duration of diabetes was also found. Most of the staining observed was cytoplasmic, suggesting that mitochondrial Ogg1 accounts primarily for the increased Ogg1 expression. CONCLUSION: We conclude that oxidative stress related DNA damage may be a novel important factor in the pathogenesis of human type 2 diabetes. An increase of Ogg1 in islet cell mitochondria is consistent with a model in which hyperglycemia and consequent increased beta-cell oxidative metabolism lead to DNA damage and the induction of Ogg1 expression.

Journal Article↗
PubMed2002

Male breast carcinoma: correlation of ER, PR, Ki-67, Her2-Neu, and p53 with treatment and survival, a study of 65 cases.

Male breast cancer is rare, and experience of it in any single institution is limited. Our current understanding regarding its biology, natural history, and treatment strategies has been extrapolated from its female counterpart. The aim of this study is to evaluate the expression patterns of estrogen receptor (ER), progesterone receptor (PR), MiB1 (Ki67), Her-2/neu (c-erbB2), and p53 and to correlate them with the prognosis, presentation, staging, management, and survival/outcome in male breast carcinoma identified through the Veterans Administration nationwide cancer registry. Sixty-five cases of male breast cancer were reviewed for classification. Tumor blocks were requested from each institution for immunohistochemical staining and evaluation of ER, PR, p53, Her2-neu, and MiB1. Seventeen age- and disease-matched male veteran patients with breast gynecomastia were used as controls. Traditional prognostic data were collected for comparison with female breast cancers (i.e., age, lymph node status, clinical staging, tumor size, histological grade, and disease-free and overall survival). Male breast carcinoma had worse disease-free survival than controls (P =.03). The clinical stage regardless of tumor size or lymph node metastasis was the single most significant prognostic factor (P <.0001). ER-positive patients appeared to have a better survival than did ER-negative patients (P =.03, univariate; P not significant in multivariate) and did not benefit from treatment with tamoxifen (P =.0027, univariate; P =.42, multivariate). MiB1 and PR expressions did not correlate with treatment or survival, and p53 was associated with shorter disease free survival (P =.07, univariate; P =.047, multivariate). Stage for stage, Her2-neu was associated with shorter disease-free survival (P <.0001) and correlated with positive lymph nodes (P =.08). Surgery alone versus surgery with adjuvant treatments (chemotherapy, radiotherapy, tamoxifen, or combination) did not show any survival difference. Adjuvant therapy seemed to be associated with worse outcome. In the Veterans Administration hospital setting, the clinical stage and the expressions of p53 and Her2-neu in male breast carcinoma may be prognostically useful markers in guiding future treatment in prospective studies, whereas ER, PR, and MiB1 expressions are of limited value.

Adult↗