Rajgopal Govindarajan

Differential processing of let-7a precursors influences RRM2 expression and chemosensitivity in pancreatic cancer: role of LIN-28 and SET oncoprotein.

Overexpression of ribonucleotide reductase subunit M2 (RRM2), involved in deoxyribonucleotide synthesis, drives the chemoresistance of pancreatic cancer to nucleoside analogs (e.g., gemcitabine). While silencing RRM2 by synthetic means has shown promise in reducing chemoresistance, targeting endogenous molecules, especially microRNAs (miRNAs), to advance chemotherapeutic outcomes has been poorly explored. Based on computational predictions, we hypothesized that the let-7 tumor suppressor miRNAs will inhibit RRM2-mediated gemcitabine chemoresistance in pancreatic cancer. Reduced expression of the majority of let-7 miRNAs with an inverse relationship to RRM2 expression was identified in innately gemcitabine-resistant pancreatic cancer cell lines. Direct binding of let-7 miRNAs to the 3′ UTR of RRM2 transcripts identified post-transcriptional regulation of RRM2 influencing gemcitabine chemosensitivity. Intriguingly, overexpression of human precursor-let-7 miRNAs led to differential RRM2 expression and chemosensitivity responses in a poorly differentiated pancreatic cancer cell line, MIA PaCa-2. Defective processing of let-7a precursors to mature forms, in part, explained the discrepancies observed with let-7a expressional outcomes. Consistently, the ratios of mature to precursor let-7a were progressively reduced in gemcitabine-sensitive L3.6pl and Capan-1 cell lines induced to acquire gemcitabine resistance. Besides known regulators of let-7 biogenesis (e.g., LIN-28), short hairpin RNA library screening identified several novel RNA binding proteins, including the SET oncoprotein, to differentially impact let-7 biogenesis and chemosensitivity in gemcitabine-sensitive versus -resistant pancreatic cancer cells. Further, LIN-28 and SET knockdown in the cells led to profound reductions in cellular proliferation and colony-formation capacities. Finally, defective processing of let-7a precursors with a positive correlation to RRM2 overexpression was identified in patient-derived pancreatic ductal adenocarcinoma (PDAC) tissues. These data demonstrate an intricate post-transcriptional regulation of RRM2 and chemosensitivity by let-7a and that the manipulation of regulatory proteins involved in let-7a transcription/processing may provide a mechanism for improving chemotherapeutic and/or tumor growth control responses in pancreatic cancer.

Transcriptional Suppression, DNA Methylation, and Histone Deacetylation of the Regulator of G-Protein Signaling 10 (RGS10) Gene in Ovarian Cancer Cells

RGS10 regulates ovarian cancer cell growth and survival, and RGS10 expression is suppressed in cell models of ovarian cancer chemoresistance. However, the mechanisms governing RGS10 expression in ovarian cancer are poorly understood. Here we report RGS10 suppression in primary ovarian cancer and CAOV-3 ovarian cancer cells compared to immortalized ovarian surface epithelial (IOSE) cells, and in A2780-AD chemoresistant cells compared to parental A2780 cells. RGS10-1 and RGS10-2 transcripts are expressed in ovarian cancer cells, but only RGS10-1 is suppressed in A2780-AD and CAOV-3 cells, and the RGS10-1 promoter is uniquely enriched in CpG dinucleotides. Pharmacological inhibition of DNA methyl-transferases (DNMTs) increased RGS10 expression, suggesting potential regulation by DNA methylation. Bisulfite sequencing analysis identified a region of the RGS10-1 promoter with significantly enhanced DNA methylation in chemoresistant A2780-AD cells relative to parental A2780 cells. DNA methylation in CAOV-3 and IOSE cells was similar to A2780 cells. More marked differences were observed in histone acetylation of the RGS10-1 promoter. Acetylated histone H3 associated with the RGS10-1 promoter was significantly lower in A2780-AD cells compared to parental cells, with a corresponding increase in histone deacetylase (HDAC) enzyme association. Similarly, acetylated histone levels at the RGS10-1 promoter were markedly lower in CAOV-3 cells compared to IOSE cells, and HDAC1 binding was doubled in CAOV-3 cells. Finally, we show that pharmacological inhibition of DNMT or HDAC enzymes in chemoresistant A2780-AD cells increases RGS10 expression and enhances cisplatin toxicity. These data suggest that histone de-acetylation and DNA methylation correlate with RGS10 suppression and chemoresistance in ovarian cancer. Markers for loss of RGS10 expression may identify cancer cells with unique response to therapeutics.

A Mild Form of SLC29A3 Disorder: A Frameshift Deletion Leads to the Paradoxical Translation of an Otherwise Noncoding mRNA Splice Variant

We investigated two siblings with granulomatous histiocytosis prominent in the nasal area, mimicking rhinoscleroma and Rosai-Dorfman syndrome. Genome-wide linkage analysis and whole-exome sequencing identified a homozygous frameshift deletion in SLC29A3, which encodes human equilibrative nucleoside transporter-3 (hENT3). Germline mutations in SLC29A3 have been reported in rare patients with a wide range of overlapping clinical features and inherited disorders including H syndrome, pigmented hypertrichosis with insulin-dependent diabetes, and Faisalabad histiocytosis. With the exception of insulin-dependent diabetes and mild finger and toe contractures in one sibling, the two patients with nasal granulomatous histiocytosis studied here displayed none of the many SLC29A3-associated phenotypes. This mild clinical phenotype probably results from a remarkable genetic mechanism. The SLC29A3 frameshift deletion prevents the expression of the normally coding transcripts. It instead leads to the translation, expression, and function of an otherwise noncoding, out-of-frame mRNA splice variant lacking exon 3 that is eliminated by nonsense-mediated mRNA decay (NMD) in healthy individuals. The mutated isoform differs from the wild-type hENT3 by the modification of 20 residues in exon 2 and the removal of another 28 amino acids in exon 3, which include the second transmembrane domain. As a result, this new isoform displays some functional activity. This mechanism probably accounts for the narrow and mild clinical phenotype of the patients. This study highlights the ‘rescue’ role played by a normally noncoding mRNA splice variant of SLC29A3, uncovering a new mechanism by which frameshift mutations can be hypomorphic.

Assembly of connexin43 into gap junctions is regulated differentially by E-cadherin and N-cadherin in rat liver epithelial cells.

E-cadherin and N-cadherin affect the assembly of connexin43 into gap junctions differentially. N-cadherin disrupts assembly by triggering endocytosis of connexin43, whereas E-cadherin facilitates the assembly.

Up-regulation of vitamin B1 homeostasis genes in breast cancer

An increased carbon flux and exploitation of metabolic pathways for the rapid generation of biosynthetic precursors is a common phenotype observed in breast cancer. To support this metabolic phenotype, cancer cells adaptively regulate the expression of glycolytic enzymes and nutrient transporters. However, activity of several enzymes involved in glucose metabolism requires an adequate supply of cofactors. In particular, vitamin B1 (thiamine) is utilized as an essential cofactor for metabolic enzymes that intersect at critical junctions within the glycolytic network. Intracellular availability of thiamine is facilitated by the activity of thiamine transporters and thiamine pyrophosphokinase-1 (TPK-1). Therefore, the objective of this study was to establish if the cellular determinants regulating thiamine homeostasis differ between breast cancer and normal breast epithelia. Employing cDNA arrays of breast cancer and normal breast epithelial tissues, SLC19A2, SLC25A19 and TPK-1 were found to be significantly up-regulated. Similarly, up-regulation was also observed in breast cancer cell lines compared to human mammary epithelial cells. Thiamine transport assays and quantitation of intracellular thiamine and thiamine pyrophosphate established a significantly greater extent of thiamine transport and free thiamine levels in breast cancer cell lines compared to human mammary epithelial cells. Overall, these findings demonstrate an adaptive response by breast cancer cells to increase cellular availability of thiamine.

Pharmacological Reversal of Histone Methylation Presensitizes Pancreatic Cancer Cells to Nucleoside Drugs: In Vitro Optimization and Novel Nanoparticle Delivery Studies

We evaluated the potential of an investigational histone methylation reversal agent, 3-deazaneplanocin A (DZNep), in improving the chemosensitivity of pancreatic cancer to nucleoside analogs (i.e., gemcitabine). DZNep brought delayed but selective cytotoxicity to pancreatic cancer cells without affecting normal human pancreatic ductal epithelial (HPDE) cells. Co-exposure of DZNep and gemcitabine induced cytotoxic additivity or synergism in both well- and poorly-differentiated pancreatic cell lines by increased apoptosis. In contrast, DZNep exerted antagonism with gemcitabine against HPDE cells with significant reduction in cytotoxicity compared with the gemcitabine-alone regimen. DZNep marginally depended on purine nucleoside transporters for its cytotoxicity, but the transport dependence was circumvented by acyl derivatization. Drug exposure studies revealed that a short priming with DZNep followed by gemcitabine treatment rather than co-treatment of both agents to produce a maximal chemosensitization response in both gemcitabine-sensitive and gemcitabine-resistant pancreatic cancer cells. DZNep rapidly and reversibly decreased trimethylation of histone H3 lysine 27 but increased trimethylation of lysine 9 in an EZH2- and JMJD1A/2C-dependent manner, respectively. However, DZNep potentiation of nucleoside analog chemosensitization was found to be temporally coupled to trimethylation changes in lysine 27 and not lysine 9. Polymeric nanoparticles engineered to chronologically release DZNep followed by gemcitabine produced pronounced chemosensitization and dose-lowering effects. Together, our results identify that an optimized DZNep exposure can presensitize pancreatic cancer cells to anticancer nucleoside analogs through the reversal of histone methylation, emphasizing the promising clinical utilities of epigenetic reversal agents in future pancreatic cancer combination therapies.

Defective hCNT1 transport contributes to gemcitabine chemoresistance in ovarian cancer subtypes: Overcoming transport defects using a nanoparticle approach

Nucleoside analogs are used as chemotherapeutic options for the treatment of platinum-resistant ovarian cancers. Human concentrative nucleoside transporter 1 (hCNT1) is implicated in sensitizing solid tumors to nucleoside analogs although its role in determining drug efficacy in ovarian cancers remains unclear. Here we examined the functional expression of hCNT1 and compared its contributions toward gemcitabine efficacy in histological subtypes of ovarian cancer. Radioactivity analysis identified hCNT1-mediated (3)H-gemcitabine transport in ovarian cancer cells to be significantly reduced compared with that of normal ovarian surface epithelial cells. Biochemical and immunocytochemical analysis identified that unlike normal ovarian cells which expressed high levels of hCNT1 at the apical cell surface, the transporter was either diminished in expression and/or mislocalized in cell lines of various subtypes of ovarian cancer. Retroviral expression of hCNT1 selectively rescued gemcitabine transport in cell lines representing serous, teratocarcinoma, and endometrioid subtypes, but not clear cell carcinoma (CCC). In addition, exogenous hCNT1 predominantly accumulated in intracytoplasmic vesicles in CCC suggesting defective cellular trafficking of hCNT1 as a contributing factor to transport deficiency. Despite diminution of hCNT1 transport in the majority of ovarian cancers and apparent trafficking defects with CCC, the chemotherapeutic efficacy of gemcitabine was broadly enhanced in all subtypes when delivered via engineered nanoparticles (NPs). Additionally, by bypassing the transport requirement, the delivery of a gemcitabine-cisplatin combination in NP formulation increased their synergistic interactions. These findings uncover hCNT1 as a putative determinant for nucleoside analog chemoresistance in ovarian cancer and may help rationalize drug selection and delivery strategies for various histological subtypes of ovarian cancer.

Differential processing of let-7a precursors as a biomarker for chemoresistance in pancreatic cancer

O of ribonucleotide reductase subunit M2 (RRM2), involved in deoxyribonucleotide synthesis, predominantly drives the chemoresistance of pancreatic cancer to nucleoside analogs (e.g., gemcitabine). While silencing RRM2 by synthetic means has shown promise in reducing chemoresistance, targeting endogenous molecules, especially microRNAs (miRNAs), to advance chemotherapeutic outcomes has been poorly explored. Based on computational predictions, we hypothesized that the let-7 tumor suppressor miRNAs will inhibit RRM2-mediated gemcitabine chemoresistance in pancreatic cancer. Reduced expression of the majority of let-7 miRNAs with an inverse relationship to RRM2 expression was identified in innately gemcitabine-resistant pancreatic cancer cell lines. Direct binding of let-7 miRNAs to the 3’ UTR of RRM2 transcripts identified post-transcriptional regulation of RRM2 influencing gemcitabine chemosensitivity. Intriguingly, overexpression of human precursor-let-7 miRNAs led to differential RRM2 expression and chemosensitivity responses in a poorly differentiated pancreatic cancer cell line, MIA PaCa-2. Defective processing of let-7a precursors to mature forms explained the discrepancies observed with let-7a expressional outcomes. Consistently, the ratios of mature to precursor let-7a were progressively reduced in gemcitabine-sensitive L3.6pl and Capan-1 cell lines induced to acquire gemcitabine resistance. Besides known regulators of let-7 biogenesis (e.g., LIN-28), short hairpin RNA library screening identified several novel RNA binding proteins, including the SET oncoprotein, to differentially impact let-7 biogenesis and chemosensitivity in gemcitabine-sensitive versus -resistant pancreatic cancer cells. Further, LIN-28 and SET knockdown in the cells led to profound reductions in cellular proliferation and colony-formation capacities. Finally, defective processing of let-7a precursors with a positive correlation to RRM2 overexpression was identified in patient-derived pancreatic ductal adenocarcinoma (PDAC) tissues. These data demonstrate an intricate posttranscriptional regulation of RRM2 and chemosensitivity by let-7a and that the accumulation of let-7a precursors as a favorable biomarker for judging chemoresistance in pancreatic cancer.W the use of screening mammography, the diagnosis of ductal carcinoma in situ (DCIS) is increasing worldwide. Patients diagnosed with DCIS either have not yet developed or may never develop invasive breast cancer (IBC). Presently, an indolent tumor can not be distinguished from a progressive tumor, making the appropriate treatment of DCIS patients, a major clinical dilemma. We are interested in developing tissue biomarkers (BM) to determine the likelihood that initial breast tumor identified on diagnostic biopsy remains contained in situ, as opposed to becoming invasive. Molecular studies predicted that the transition from in situ to invasive disease was associated with quantitative rather than qualitative differences in gene and protein expression. We developed imaging-based method to measure protein expression as a continuous variable in fixed tissue. We assumed that DCIS accompanying microinvasive carcinoma (T1mic) represented an early progressive DCIS, because invasion increases the likelihood of metastasis. We theorized that molecular BMs of progressive DCIS are the measurable parameters that distinguish cells in in situ component of T1mic from cells in normal/benign epithelium. We performed quantitative protein profiling on 210 archived tissues: 42 histologically normal, 19 benign, 54 cancer in situ, and 95 IBC. Our measurements in DCIS revealed previously unidentified quantitative differences in the insulin-like growth factor I receptor, Ras oncogene like protein 1, and Rho GTPase guanine nucleotide exchange factor VAV2, the proteins implicated in the regulation of invasion in preclinical models. These new findings may open doors to molecular-based predictions of individualized risk for developing invasion in DCIS.High quality biospecimens with appropriate clinical annotation are critical in the era of biomarker discovery in personalized medicine. Several pre-analytical variables affect human biospecimen integrity for biomarker research in cancer. This situation is applicable to a variety of biospecimens including plasma/serum and fixed cancer tissues used for biomarker analysis. The U.S. National Cancer Institute (NCI) Biorepositories and Biospecimen Research Branch (BBRB) was established in 2005 to coordinate NCI’s biospecimen resource activities and address those issues that affect access to the high quality specimens for biomarker research. A Biospecimen Research Network (BRN) was established to fund research to develop additional evidence-based practices used to develop serum and tissue biomarkers for human biospecimen integrity. We describe the development of assays and identification of biomarkers that may be used as sentinel markers of plasma/tissue stability in biobanks using mass-spectroscopy proteomics, circulating miRNA and immunostaining of FFPE tissues (AQUA technology). The first NCI/BBRB-funded project involves the identification of protein biomarkers using mass-spectrometry and illumina arrays in serum obtained from breast cancer and matched normal subjects, to develop guidelines for blood collection and storage. A second project studied effects of pre-analytical variables on circulating miRNA and identification and validation of new and improved housekeeping miRNA and biomarkers associated with breast cancer. In another study, a series of biomarkers have been validated by construction of tissue microarray (TMA) from 93 breast cancer specimens with known time to fixation as a pre-analytical variable. A tissue quality index (TQI) model was generated to predict the time to fixation and tissue quality by studying a subset of biomarker proteins in breast cancer tissues using AQUA scores. This presentation will outline the progressive efforts taken by BRN, investigator-led projects to identify and validate biomarkers for human biospecimen integrity.F of bioactive lipids by oxygenases is known to play both a protective and pro-thrombotic role in circulation. 12-lipoxygenase (12-LOX) and its oxidized products play an important but unresolved role in regulation of platelet function. 12-LOX oxidation of the fatty acid, dihomo-γ-linolenic acid (DGLA), produces the novel bioactive metabolite 12-hydroxyeicosatetrienoic acid (12(S)-HETrE). Recent work suggests that while 12(S)-HETE (produced from 12-LOX oxidation of AA) is pro-thrombotic to the platelet, 12(S)-HETrE acts in a protective manner in platelets to limit activation. Therefore, we sought to identify the mechanism by which DGLA inhibits platelet activation through 12(S)-HETrE. Delineating the mechanism by which this previously unknown metabolite regulates cellular activity is essential to begin to understand how 12-LOX oxidation of DGLA can potentially lead to regulation of a number of physiological processes including thrombosis. To address these questions, we have employed pharmacological and whole animal studies. Pharmacological intervention has confirmed an integral role of 12-HETrE production through 12-LOX to negatively regulate activity in the platelet. These observations have been confirmed in mice lacking the 12-LOX gene. Further, dietary supplementation of DGLA-enriched chow supports our ex vivo studies exogenously adding DGLA and/or 12-HETrE to attenuate agonist-induced platelet activation. Hence, these studies are the first to begin to elucidate the underlying mechanisms by which omega-3 and 6 fatty acids are protective against cardiovascular disease and stroke.P genetics has been unable to replicate studies which link genotype with treatment outcome. In large measure the difficulty in producing reliable markers has been a consequence of the heterogeneity of depression. Almost all depression trials or genetic studies use “response” as the surrogate outcome measure. By definition, response is defined as a 50% reduction on analytical metric when comparing entry and exit from the trial. This implies that subjects remain symptomatic for their presenting symptoms. We have analyzed The Sequenced Treatment Alternatives for Relieving Depression (STAR*D) NIMH multicenter clinical. An endophenotype was defined by baseline depression severity and minimal co-morbidity. The outcome metric we utilized compared non-responders with true remitters. No subjects defined as responders were included in our genotypic analysis. Polymorphic markers were chosen before genotypic analysis. We identified 255 subjects of European/Caucasian ancestry who met our inclusion criteria with 66% non-responders and 33% true remitters. To our knowledge this is the first genetic analysis of depression subjects where the relevant surrogate clinical outcome of symptom relief was used. Our analysis identified 27 SNPs in 12 genes within muscarinic, nicotinic, adrenergic, serotonergic, dopaminergic, reward and signal transduction pathways. A haplotype analysis indicates that certain alleles can predict true remission. Our findings demonstrate using an endophenotypic analysis can identify biomarkers predicting relevant clinical outcomes in depression. Further work is underway to validate the original findings in additional data sets and novel depressed patients.Biological samples from patients are invaluable. Ideally the samples should be preserved for the same period of time as the duration of their corresponding medical records. Urine is a body fluid that can be non-invasively acquired and contains important biological information about the patient. Simple and inexpensive urinary protein sample preservation can be the starting point for comprehensive biological sample storage just like medical record of patients. Here, we propose a method to adsorb urinary proteins to a membrane named Urimem that can then be dried and stored. This method is very simple and inexpensive and requires minimal sample handling. It does not use organic solvents. The proteins on the membrane are dry and are prevented from degradation. The membrane may even be able to be stored at room temperature at least for weeks. The quantity of eluted proteins from a membrane is sufficient for biomarker validation experiments. Comprehensive historical biological information can also be used in retrospective studies to understand the pathophysiology of disease and the relationships among diseases as well as to monitor the long-term efficacy and side effects of treatments. With this information, medical research can be conducted more easily, considerably faster, and more economically, ultimately benefiting the patients who provided the samples. Thus, we believe that it is possible to preserve urinary protein samples from each stage of disease development for every consenting patient in a hospital. This can potentially change the landscape of medical research and medical practice in the future.Phosphatidylserine (PS) exposure is one of the most prominent and ubiquitous fingerprints of dying cells, making it an attractive biomarker for molecular imaging. Synthetic bis-zinc(II)-dipicolylamine (Zn-DPA) derivatives have high selectivity for biological membranes enriched with PS. Our study aims to apply PET/NIRF imaging with a novel DPA-containing probe ( 18 F-MTTI-170) to visualize and evaluate cell death induced by Paclitaxel in a U87MG tumor xenograft model. In vitro toxicity of Paclitaxel to U87MG cells was determined by a colorimetric assay. The response of U87MG cells to Paclitaxel treatment was determined by flow cytometry, fluorescence staining, and cell uptake study. Established U87MG tumors in nude mice were daily treated with a combination of All-Trans Retinoic Acid (ATRC) (1.5 μg/kg) and Paclitaxel (45 μg/kg). Longitudinal PET imaging was performed with 18 F-MTTI-170 before treatment and at day 3, 6, and 9 after treatment. NIRF imaging was carried out with 19 F-MTTI-170 before treatment and at day 4, 7, and 11 after treatment. Our data demonstrated that U87MG human glioma cells are sensitive to Paclitaxel treatment. After being treated with Paclitaxel for 15 h, U87MG cells were stained with PSVue643 (Cy5-Zn-DPA). The strong red fluorescence signal was identified in the cytosol of the treated cells but not on the untreated cells. Besides, the fluorescent signal was effectively blocked by co-incubation with excess amount of unlabeled Zn-DPA. For cell uptake study, about 1.5% of 18 F-MTTI-170 uptake in Paclitaxel-treated U87MG cells was determined after 1 hr incubation, which is significantly higher than 0.69% and 0.39% observed for 18 F-FP-DPA (single modality compound) and F-FP-Dye (negative control), suggesting that the Zn-DPA moiety is indeed the component binding to PS, and the cell uptake of 18 F-MTTI-170 is significantly higher than that of 18 F-FP-DPA. Daily treatment with ATRC and Paclitaxel effectively inhibited the growth of U87MG tumors by inducing cell death. The cell death was clearly visualized by 18 F-MTTI-170 PET. The tumor uptake, which was observed at day 9 after treatment, was significantly higher than that in the untreated tumors with a ratio of 6.70. The NIRF imaging results are consistent with the findings by PET. In conclusion, PET/NIRF imaging with MTTI-170 is sensitive enough to allow visualization of Paclitaxel induced cell death in U87MG tumor xenograft model. Fully quantitative imaging of tumor response to therapy with MTTI-170 offers the potential to provide early assessment of cancer treatment efficacy leading to individually tailored therapeutic plans with improved outcomes.Serum neuron-specific enolase (NSE) and S-100β levels are considered novel biochemical markers of neuronal cell injury. In this study, the initial and post-treatment levels of NSE and S-100β were compared in carbon monoxide (CO) poisoning patients, who received normorbaric oxygen (NBO) or hyperbaric oxygen (HBO) therapy. Forty consecutive patients with acute CO poisoning were enrolled in this prospective, observational study. According to their clinical symptoms and observations, twenty patients were treated with NBO, and the other twenty with HBO. Serum S-100β and NSE levels were measured both at time of admission and 6 h later (post-treatment). Serum NSE and S-100β values decreased significantly in both of the therapeutic modalities. The initial and post-treatment values of NSE and S-100β in NBO or HBO patients were comparable. A clear negative correlation was observed between the decrease of NSE and S-100β levels and initial blood carboxyhemoglobin levels. In conclusion, the present results suggested the use of serum S-100β and NSE levels as indicators for brain injury. Due to the significant increase of their values with oxygen therapy, they may also be useful as prognostic follow-up markers. However, the current findings reflected no difference between the efficacy of NBO or HBO therapy.T activation of NFκB, a central coordinator of immune responses, is tightly regulated in order to achieve its normal transient activation in response to stress. In cancer, NFκB is activated abnormally, contributing to oncogenesis and progression. The regulation of transient activation is complex, and we are still learning the details of how the essential fine control is achieved. Here, we uncover a novel regulatory pathway for NFκB that is driven by cycles of lysine methylation and demethylation. Using a novel lentiviral Validation-Based Insertional Mutagenesis (VBIM) method, we identified the F-box leucine repeat rich protein 11 (FBXL11), a known histone H3 lysine 36 (H3K36) demethylase, as a potent negative regulator of NFκB. Deletion of the demethylase domain of FBXL11 abolishes this activity. Knocking the expression of FBXL11 down activates NFκB, as does over-expression of the corresponding histone H3K36 methylase, NSD1. The p65 subunit of NFκB binds to NSD1 and FBXL11, and significant methylation of K218 and K221 of p65 was detected in cells with constitutively active NFκB or upon cytokine stimulation. Importantly, FBXL11 is transcribed in response to NFκB activation and thus, like the well known inhibitor IκB, FBXL11 participates in an auto-regulatory negative feedback loop. We show that lysine methylation is an important regulatory post-translational modification of NFκB that is mediated by the FBXL11-NSD1 enzyme pair. Furthermore, we demonstrate that the VBIM technique is a powerful tool for gene discovery that has broad applications in many different systems.H we report a core-shell plasmonic nanoparticle (NP) design based on silver nanodecahedrons (Ag NDs). We have developed a new photo-assisted synthesis process to prepared the Ag NDs and a self-assembly procedure to coat the Ag NDs with a uniform layer of silica in which Raman tags may be incorporated. This core-shell Ag nano-composite exhibits strong surface enhanced Raman scattering (SERS) because of its localized surface plasmon resonance (LSPR). A unique property offered by the Ag NDs is their widely tunable LSPR peak between 420 660 nm. Until now, there are very few reported cases of Ag nanoparticles that exhibit LSPR in the RED region since the natural plasmonic resonance of Ag occurs in the UV-blue region. This has led to problems with most Raman-active tags as they only produce transition-enhanced Raman signal in the REDGREEN region. The core-shell design also ensures that the Ag nano-particles are completely protected against degradation due to oxidation. As a result of the reported core-shell Ag NDs, the use of Raman tags for labeling biomolecules now has a much better prospect. Raman-based labeling is known to be a better choice than the common fluorescence approach because of the wide spectral diversity offered by Raman tags. In addition, field enhancement due to LSPR in the core-shell Ag NDs may lead to a variety of applications including non-linear harmonics generation, photo-induced reaction with long wavelength radiation and florescence enhancement.Personalized and molecular-based cancer treatment depends on biomarkers. Biomarker research and assay development is becoming increasingly important because it drives drug discovery, clinical diagnostics, prognostics and treatment decisions. Immunohistochemistry (IHC), which examines protein localization with preserved tissue morphology, is one of the most important assays to detect protein biomarkers. This technique has been applied in many facets of biological science, especially in assays required using archival formalin-fixed, paraffin embedded (FFPE) tissues. The major challenges for IHC are sensitivity and quantification. AQUA (Automatic Quantitative Analysis) is a fluorescence IHC imaging analysis technology that could automatically quantify protein expression in tissues with high sensitivity and accuracy. We have applied AQUA technology for both basic and clinical research. Using this technology, we identified biomarkers that related to cetuximab treatment in a mouse xenograft model. We determined the expression of certain proteins in cancer patient cohorts and correlated the protein expression levels with pathologic and clinical outcomes. We found several proteins that could serve as prognostic or predictive biomarkers. With the emergence of new biomarkers from recent genetic discoveries, numerous novel targeted therapies for cancer are already in clinical trials, with many more to be developed in the coming decades. Personalized medicine is about the identification of patients that are most likely to benefit from treatment and assess treatment response. AQUA technology can dramatically speed up the progress of such challenges and therefore represents the future for biomarker research. Biography Yang is an Assistant Professor at Fox Chase Cancer Center, where she takes charge of the Tissue Research Service at the Biosample Repository Core Facility. She is a leading expert in the field of immunohistochemistry (IHC) and quantitative analysis. She has applied IHC to study the molecular alterations of known and novel signaling pathways that regulate embryogenesis, organ morphogenesis and tumorigenesis. Her research results can be found in prestigious journals such as Development, Am. J. Path., JBC et. al. Recently Dr. Yang extended the automatic quantitative analysis (AQUA) IHC assay system for tumor biomarker research. Dr. Yang serves in the editorial board of the Journal of Cancer Research Updates and the Journal of Analytical Oncology. She is ad hoc reviewers in a number of journals including Biomarkers, Biochemical Pharmacology, Current Pharmaceutical Biotechnology, Current Proteomics, Experimental Neurology et.al.M technologies have recently come to the fore in the context of biomarker discovery. Metabolic dysfunction is a noted hallmark in numerous disease states, and thus multivariate measurement and analysis of metabolite parameters provides a potential window into both diagnostic as well as prognostic realms. In this presentation, the advantages and disadvantages of biomarker discovery by NMR metabolomics methods will be discussed. In particular, the use of quantitative methods for metabolite analysis will be contextulized against other tools such as mass spectrometry based metabolite discovery. A biological context will be provided in our clinical oncology studies in the areas of pancreatic, colorectal, lung and brain cancer.O of the HER2/neu receptor occurs in 15 to 30 percent of breast tumors and is linked to poorer prognosis. Currently HER2/neu expression status determines whether patient will receive trastuzumabbased treatment. In clinical practice, overexpression of HER2/neu is identified using IHC or FISH, both of which are invasive approaches requiring tissue samples. Serum assays for HER2/neu receptor have been reported but the use is very limited due to serum interference factors (e.g. human anti-animal antibodies) that lead to false test results and inconsistency with tissue Her2 status. We have developed an ELISA based approach implementing an MBB buffer to eliminate false results and to obtain more accurate assessment of HER2/neu levels. Using this refined assay we retroactively measured HER2/neu levels from 56 patients. Pre-treatment (e.g. surgery, radiation, or chemotherapy) samples were available from 12 patients, of which 6 patients were tissue HER2/neu positive and the other six were negative. All the HER2/ neu positive samples had higher serum levels than negative ones (p < 0.05). We observed a decrease in serum HER-2/neu values after surgery in two out of 5 patients. In 5 patients experienced recurrence or metastasis, HER2/neu level significantly increased from the treatment-established baseline, accompanying recurrence and before metastasis. Our results indicate that we can monitor HER2 ECD as a biomarker over the course of disease progression and treatment.N antibodies against viruses represent a major mechanism of host protection against viral infections. Most if not all marketed vaccines elicit neutralizing antibodies. Currently, neutralizing anti-viral therapeutic monoclonal antibodies are being developed for the treatment and/or the prevention of viral diseases. Standard neutralization assays to assess the viral neutralization activities of antibodies have historically been functional plaque assays. Plaque assays are time-consuming, laborintensive and challenging to implement in clinical studies especially those involving a large number of patients. Here we described the development and implementation of fast and robust Fluorescent Foci (FFA)-based microneutralization (MN) assays. These assays, using viruses expressing enhanced green fluorescence protein (EGFP), allow for higher throughput, better precision, and shorter assay turn-around time making them suitable for use in large clinical studies. We will first describe the establishment of a novel FFA-based MN assay to detect and quantify neutralizing antibodies against EBV. This assay uses EBV-GFP and an engineered epithelial cell line. All assay conditions impacting assay performance were optimized and the assay was automated using liquid handling and high-content imaging systems. The robustness and precision of the optimized assay were demonstrated using serum samples from mice, rabbits and humans (n > 600). In addition, a companion EBV-specific IgG ELISA assay was developed. Significant correlation (r2 = 0.89) between both assays was demonstrated using 358 rabbit serum samples. A MN assay was similarly developed for Respiratory Syncytial virus (RSV) to support the development of MedImmune’s anti-RSV therapeutic mAbs and RSV vaccine candidates. The 2-year assay control trending of RSV MN assay will be presented to demonstrate the robustness and precision of this assay.

Abstract A30: Inhibiting histone methylation as an epigenetic therapeutic approach for pancreatic cancer

We evaluated the potential of an investigational histone methylation reversal agent, 3-deazaneplanocin A (DZNep), in improving the chemosensitivity of pancreatic cancer to nucleoside analogs (i.e., gemcitabine). DZNep brought delayed but selective cytotoxicity to pancreatic cancer cells without affecting normal human pancreatic ductal epithelial (HPDE) cells. Co-exposure of DZNep and gemcitabine induced cytotoxic additivity or synergism in both well- and poorly-differentiated pancreatic cell lines. In contrast, DZNep exerted antagonism with gemcitabine against HPDE cells with significant reduction in cytotoxicity compared with the gemcitabine-alone regimen. DZNep marginally depended on purine nucleoside transporters for its cytotoxicity, but the transport dependence was circumvented by acyl derivatization. Drug exposure studies revealed that a short priming with DZNep followed by gemcitabine treatment rather than co-treatment of both agents to produce a maximal chemosensitization response in both gemcitabine-sensitive and gemcitabine-resistant pancreatic cancer cells. DZNep rapidly and reversibly decreased trimethylation of histone H3 lysine 27 but increased trimethylation of lysine 9 in an EZH2- and JMJD1A/2C-dependent manner, respectively. However, DZNep potentiation of nucleoside analog chemosensitization was found to be temporally coupled to trimethylation changes in lysine 27 and not lysine 9. Polymeric nanoparticles engineered to chronologically release DZNep followed by gemcitabine produced pronounced chemosensitization and dose-lowering effects. Together, our results identify that an optimized DZNep exposure can presensitize pancreatic cancer cells to anticancer nucleoside analogs through the reversal of histone methylation, emphasizing the promising clinical utilities of epigenetic reversal agents in future pancreatic cancer combination therapies. Citation Format: Rajgopal Govindarajan. Inhibiting histone methylation as an epigenetic therapeutic approach for pancreatic cancer. [abstract]. In: Proceedings of the AACR Special Conference on Chromatin and Epigenetics in Cancer; Jun 19-22, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2013;73(13 Suppl):Abstract nr A30.

Abstract 1025: Optimized DZNep exposure presensitizes pancreatic cancer cells to anticancer nucleoside analogues: potential clinical implications.

We evaluated the potential of a histone methylation reversal agent 3-deazaneplanocin A (DZNep) in improving the chemosensitivity of pancreatic cancer to nucleoside analogs (i.e., gemcitabine). DZNep brought delayed but selective cytotoxicity to pancreatic cancer cells without affecting normal human pancreatic ductal epithelial (HPDE) cells. Co-exposure of DZNep and gemcitabine induced cytotoxic additivity or synergism in both well- and poorly-differentiated pancreatic cell lines. In contrast, DZNep exerted antagonism with gemcitabine against HPDE cells with significant reduction in cytotoxicity compared with the gemcitabine-alone regimen. DZNep marginally depended on purine nucleoside transporters for its cytotoxicity, but the transport dependence was circumvented by acyl derivatization. Drug exposure studies revealed that a short priming with DZNep followed by gemcitabine treatment rather than co-treatment of both agents produced a maximal chemosensitization response in both gemcitabine-sensitive and gemcitabine-resistant pancreatic cancer cells. DZNep rapidly and reversibly decreased trimethylation of histone H3 lysine 27 but increased trimethylation of lysine 9 in an EZH2- and JMJD1A/2C-dependent manner, respectively. However, DZNep potentiation of nucleoside analog chemosensitization was found to be temporally coupled to trimethylation changes in lysine 27 and not lysine 9. Polymeric nanoparticles engineered to chronologically release DZNep followed by gemcitabine produced pronounced chemosensitization and dose-lowering effects. Together, our results identify that an optimized DZNep exposure can presensitize pancreatic cancer cells to anticancer nucleoside analogs and emphasize the promising clinical utilities of histone methylation reversal agents in future pancreatic cancer combination therapies. Citation Format: Sau Wai Hung, Hardik Mody, Sean Marrache, Yangzom D. Bhutia, Franklin Davis, Jong Hyun Cho, Shanta Dhar, Chung K. Chu, Rajgopal Govindarajan. Optimized DZNep exposure presensitizes pancreatic cancer cells to anticancer nucleoside analogues: potential clinical implications. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1025. doi:10.1158/1538-7445.AM2013-1025