Medical Molecular Biology Commons^™

Novel Role Of Pancreatic Differentiation 2 In Facilitating Self-Renewal And Drug Resistance Of Pancreatic Cancer Stem Cells., Arokia P. Vaz, Moorthy P. Ponnusamy, Satyanarayana Rachagani, P Dey, Apar Kishor Ganti, Surinder K. Batra

Journal Articles: Biochemistry & Molecular Biology

BACKGROUND: Cancer stem cells (CSCs) contribute towards disease aggressiveness and drug resistance. Specific identification of CSC maintenance genes and targeting can improve the efficiency of currently available treatment modalities. Pancreatic differentiation 2 (PD2) has a major role in the self-renewal of mouse embryonic stem cells. In the present study, we investigated the role of PD2 in pancreatic CSCs.

METHODS: Characterisation of CSCs and non-CSCs from mouse models, pancreatic cancer cells and human tissues by CSC and self-renewal marker analysis using confocal assay. Effect of PD2 knockdown in CSCs (after gemcitabine treatment) was studied by immunoblot and apoptosis assays.

RESULTS: A …

Impaired Expression Of Protein Phosphatase 2a Subunits Enhances Metastatic Potential Of Human Prostate Cancer Cells Through Activation Of Akt Pathway., P Pandey, Parthasarathy Seshacharyulu, Srustidhar Das, Satyanarayana Rachagani, Moorthy P. Ponnusamy, Y Yan, Sonny L. Johansson, K Datta, Ming-Fong Lin, Surinder K. Batra

Journal Articles: Biochemistry & Molecular Biology

BACKGROUND: Protein phosphatase 2A (PP2A) is a dephosphorylating enzyme, loss of which can contribute to prostate cancer (PCa) pathogenesis. The aim of this study was to analyse the transcriptional and translational expression patterns of individual subunits of the PP2A holoenzyme during PCa progression.

METHODS: Immunohistochemistry (IHC), western blot, and real-time PCR was performed on androgen-dependent (AD) and androgen-independent (AI) PCa cells, and benign and malignant prostate tissues for all the three PP2A (scaffold, regulatory, and catalytic) subunits. Mechanistic and functional studies were performed using various biochemical and cellular techniques.

RESULTS: Through immunohistochemical analysis we observed significantly reduced levels of PP2A-A …

Protein Synthesis Factors (Rf1, Rf2, Rf3, Rrf, And Tmrna) And Peptidyl-Trna Hydrolase Rescue Stalled Ribosomes At Sense Codons., Serafín Vivanco-Domínguez, José Bueno-Martínez, Gloria León-Avila, Nobuhiro Iwakura, Akira Kaji, Hideko Kaji, Gabriel Guarneros

Department of Biochemistry and Molecular Biology Faculty Papers

During translation, ribosomes stall on mRNA when the aminoacyl-tRNA to be read is not readily available. The stalled ribosomes are deleterious to the cell and should be rescued to maintain its viability. To investigate the contribution of some of the cellular translation factors on ribosome rescuing, we provoked stalling at AGA codons in mutants that affected the factors and then analyzed the accumulation of oligopeptidyl (peptides of up to 6 amino acid residues, oligopep-)-tRNA or polypeptidyl (peptides of more than 300 amino acids in length, polypep-)-tRNA associated with ribosomes. Stalling was achieved by starvation for aminoacyl-tRNA(Arg4) upon induced expression of …

Ribosome Recycling Step In Yeast Cytoplasmic Protein Synthesis Is Catalyzed By Eef3 And Atp., Shinya Kurata, Klaus H Nielsen, Sarah F Mitchell, Jon R Lorsch, Akira Kaji, Hideko Kaji

Department of Biochemistry and Molecular Biology Faculty Papers

After each round of protein biosynthesis, the posttermination complex (PoTC) consisting of a ribosome, mRNA, and tRNA must be disassembled into its components for a new round of translation. Here, we show that a Saccharomyces cerevisiae model PoTC was disassembled by ATP and eukaryotic elongation factor 3 (eEF3). GTP or ITP functioned with less efficiency and adenosine 5gamma'-(beta,gamma-imido)triphosphate did not function at all. The k(cat) of eEF3 was 1.12 min(-1), which is comparable to that of the in vitro initiation step. The disassembly reaction was inhibited by aminoglycosides and cycloheximide. The subunits formed from the yeast model PoTC remained separated …

P66shc--A Longevity Redox Protein In Human Prostate Cancer Progression And Metastasis : P66shc In Cancer Progression And Metastasis., Mythilypriya Rajendran, Paul Thomes, Li Zhang, Suresh Veeramani, Ming-Fong Lin

Journal Articles: Biochemistry & Molecular Biology

p66Shc, a 66 kDa proto-oncogene Src homologous-collagen homologue (Shc) adaptor protein, is classically known in mediating receptor tyrosine kinase signaling and recently identified as a sensor to oxidative stress-induced apoptosis and as a longevity protein in mammals. The expression of p66Shc is decreased in mice and increased in human fibroblasts upon aging and in aging-related diseases, including prostate cancer. p66Shc protein level correlates with the proliferation of several carcinoma cells and can be regulated by steroid hormones. Recent advances point that p66Shc protein plays a role in mediating cross-talk between steroid hormones and redox signals by serving as a common …

The Human Rna Polymerase Ii-Associated Factor 1 (Hpaf1): A New Regulator Of Cell-Cycle Progression., Nicolas Moniaux, Christophe Nemos, Shonali Deb, Bing Zhu, Irena Dornreiter, Michael A. Hollingsworth, Surinder K. Batra

Journal Articles: Biochemistry & Molecular Biology

BACKGROUND: The human PAF (hPAF) complex is part of the RNA polymerase II transcription apparatus and regulates multiple steps in gene expression. Further, the yeast homolog of hPaf1 has a role in regulating the expression of a subset of genes involved in the cell-cycle. We therefore investigated the role of hPaf1 during progression of the cell-cycle.

METHODOLOGY/FINDINGS: Herein, we report that the expression of hPaf1, a subunit of the hPAF complex, increases with cell-cycle progression and is regulated in a cell-cycle dependant manner. hPaf1 specifically regulates a subclass of genes directly implicated in cell-cycle progression during G1/S, S/G2, and G2/M. …

Revisiting Histidine-Dependent Acid Phosphatases: A Distinct Group Of Tyrosine Phosphatases., Suresh Veeramani, Ming-Shyue Lee, Ming-Fong Lin

Journal Articles: Biochemistry & Molecular Biology

Although classical protein tyrosine phosphatase (PTP) superfamily members are cysteine-dependent, emerging evidence shows that many acid phosphatases (AcPs) function as histidine-dependent PTPs in vivo. These AcPs dephosphorylate phospho-tyrosine substrates intracellularly and could have roles in development and disease. In contrast to cysteine-dependent PTPs, they utilize histidine, rather than cysteine, for substrate dephosphorylation. Structural analyses reveal that active site histidine, but not cysteine, faces towards the substrate and functions as the phosphate acceptor. Nonetheless, during dephosphorylation, both histidine-dependent and cysteine-dependent PTPs use their active site arginine and aspartate for substrate binding and proton donation, respectively. Thus, we propose that they should …

Caveolin-1, Tgf-Β Receptor Internalization, And The Pathogenesis Of Systemic Sclerosis, Francesco Del Galdo, Michael P. Lisanti, Sergio A. Jimenez

Jefferson Institute of Molecular Medicine Papers and Presentations

PURPOSE OF REVIEW: To review the scientific literature supporting the participation of caveolin-1 in the pathogenesis of tissue fibrosis and the notion that modulation of the caveolin-1 pathway may represent a novel treatment for systemic sclerosis and other fibrotic diseases.

RECENT FINDINGS: Caveolin-1 plays an important role in the regulation of transforming growth factor-beta (TGF-beta) signaling owing to its participation in TGF-beta receptor internalization. TGF-beta receptor internalized through caveolin-1 lipid rafts undergoes rapid degradation, effectively decreasing TGF-beta signaling. Studies have shown that caveolin-1 knockdown in vitro markedly increased collagen gene expression in normal human lung fibroblasts. Caveolin-1 was reduced in …

Deregulation Of Muc4 In Gastric Adenocarcinoma: Potential Pathobiological Implication In Poorly Differentiated Non-Signet Ring Cell Type Gastric Cancer., S. Senapati, P. Chaturvedi, P. Sharma, G Venkatraman, Jane L. Meza, W. El-Rifai, H. K. Roy, Surinder K. Batra

Journal Articles: Biochemistry & Molecular Biology

MUC4 is a large, heavily glycosylated transmembrane mucin, that is implicated in the pathogenesis of various types of cancers. To date, no extensive study has been done to check the expression and functional significance of MUC4 in different types of gastric adenocarcinomas. Here, we report the expression profile of MUC4 in gastric adenocarcinomas and its function in poorly differentiated gastric non-signet ring cell carcinoma (non-SRCC) type cells. Immunohistochemical analysis using tissue microarray (TMA) showed a significant difference in MUC4 expression between normal adjacent (n = 45) and gastric adenocarcinoma (n = 83; P < 0.001). MUC4 expression was not associated with tumour type, stage or with the degree of differentiation. To gain further insight into the significance of MUC4 expression in gastric non-SRCC cells, MUC4 was ectopically expressed in AGS, a poorly differentiated gastric non-signet ring cell line. The MUC4 overexpressing cells (AGS-MUC4) showed a significant increase (P < 0.005) in cell motility and a decrease in cellular aggregation as compared with the vector-transfected cells. Furthermore, in vivo tumorigenicity analysis revealed that animals transplanted with the MUC4 overexpressing cells (AGS-MUC4) had a greater incidence of tumours (83%) in comparison to empty vector control (17%). In addition, the expression of MUC4 resulted in enhanced expression of total cellular ErbB2 and phosphorylated ErbB2. In conclusion, our results showed that MUC4 is overexpressed in gastric adenocarcinoma tissues, and that it has a role in promoting aggressive properties in poorly differentiated gastric non-SRCC cells through the activation of the ErbB2 oncoprotein.

Mitochondrial Redox Signaling By P66shc Is Involved In Regulating Androgenic Growth Stimulation Of Human Prostate Cancer Cells., Suresh Veeramani, Ta-Chun Yuan, Fen-Fen Lin, Ming-Fong Lin

Journal Articles: Biochemistry & Molecular Biology

p66Shc is shown to negatively regulate the life span in mice through reactive oxygen species (ROS) production. Recent reports, however, revealed that p66Shc protein level is significantly elevated in several human cancer tissues and growth-stimulated carcinoma cells, suggesting a mitogenic and carcinogenic role for p66Shc. In this communication, we demonstrate for the first time that p66Shc mediates androgenic growth signals in androgen-sensitive human prostate cancer cells through mitochondrial ROS production. Growth stimulation of prostate cancer cells with 5alpha-dihydrotestosterone (DHT) is accompanied by increased p66Shc level and ROS production, which is abolished by antioxidant treatments. However, antioxidant treatments do not affect …

Muc4 And Muc5ac Are Highly Specific Tumour-Associated Mucins In Biliary Tract Cancer., W. R. Matull, F. Andreola, A. Loh, Z. Adiguzel, M. Deheragoda, U. Qureshi, Surinder K. Batra, D. M. Swallow, S. P. Pereira

Journal Articles: Biochemistry & Molecular Biology

Alterations in epithelial mucin expression are associated with carcinogenesis, but there are few data in biliary tract cancer (BTC). In pancreatic malignancy, MUC4 is a diagnostic and prognostic tumour marker, whereas MUC5AC has been proposed as a sensitive serological marker for BTC. We assessed MUC4 and MUC5AC expression in (i) prospectively collected bile and serum specimens from 72 patients with biliary obstruction (39 BTC) by real-time reverse transcriptase-PCR (qPCR) and western blot analysis, and (ii) 79 archived biliary tissues (69 BTC) by immunohistochemistry. In bile, MUC4 protein was detected in 27% of BTC and 29% of primary sclerosing cholangitis (PSC) …

Early Diagnosis Of Pancreatic Cancer: Neutrophil Gelatinase-Associated Lipocalin As A Marker Of Pancreatic Intraepithelial Neoplasia., N. Moniaux, S. Chakraborty, M. Yalniz, J. Gonzalez, Valerie K. Shostrom, J. Standop, Subodh M. Lele, Michel M. Ouellette, Parviz M. Pour, Aaron Sasson, R. E. Brand, Michael A. Hollingsworth, Maneesh Jain, Surinder K. Batra

Journal Articles: Biochemistry & Molecular Biology

Pancreatic cancer is a highly lethal malignancy with a dismal 5-year survival of less than 5%. The scarcity of early biomarkers has considerably hindered our ability to launch preventive measures for this malignancy in a timely manner. Neutrophil gelatinase-associated lipocalin (NGAL), a 24-kDa glycoprotein, was reported to be upregulated nearly 27-fold in pancreatic cancer cells compared to normal ductal cells in a microarray analysis. Given the need for biomarkers in the early diagnosis of pancreatic cancer, we investigated the expression of NGAL in tissues with the objective of examining if NGAL immunostaining could be used to identify foci of pancreatic …

An Intramolecular Association Between Two Domains Of The Protein Kinase Fused Is Necessary For Hedgehog Signaling, Manuel Ascano Jr., David J. Robbins

Dartmouth Scholarship

The protein kinase Fused (Fu) is an integral member of the Hedgehog (Hh) signaling pathway. Although genetic studies demonstrate that Fu is required for the regulation of the Hh pathway, the mechanistic role that it plays remains largely unknown. Given our difficulty in developing an in vitro kinase assay for Fu, we reasoned that the catalytic activity of Fu might be highly regulated. Several mechanisms are known to regulate protein kinases, including self-association in either an intra- or an intermolecular fashion. Here, we provide evidence that Hh regulates Fu through intramolecular association between its kinase domain (ΔFu) and its carboxyl-terminal …

Muc4 Mucin Expression In Human Pancreatic Tumours Is Affected By Organ Environment: The Possible Role Of Tgfbeta2., A. Choudhury, N. Moniaux, A. B. Ulrich, B. M. Schmied, J. Standop, Parviz M. Pour, S. J. Gendler, Michael A. Hollingsworth, J-P Aubert, Surinder K. Batra

Journal Articles: Biochemistry & Molecular Biology

MUC4 is highly expressed in human pancreatic tumours and pancreatic tumour cell lines, but is minimally or not expressed in normal pancreas or chronic pancreatitis. Here, we investigated the aberrant regulation of MUC4 expression in vivo using clonal human pancreatic tumour cells (CD18/HPAF) grown either orthotopically in the pancreas (OT) or ectopically in subcutaneous tissue (SC) in the nude mice. Histological examination of the OT and SC tumours showed moderately differentiated and anaplastic morphology, respectively. The OT tumour cells showed metastases to distant lymph nodes and faster tumour growth (P

Expression Of Tumor-Associated Glycoprotein-72 (Tag-72) Antigen In Human Prostatic Adenocarcinomas., Dev Karan, Sonny L. Johansson, Ming-Fong Lin, Surinder K. Batra

Journal Articles: Biochemistry & Molecular Biology

Tumor-specific antigens are usually defined by monoclonal antibodies (MAbs) and can play critical roles in the diagnosis and therapy of carcinomas. Despite advances in the understanding of the molecular genetics of human prostate carcinomas, therapeutic approaches require that tumor-specific markers, preferably on the cell surface, should be defined. In this study, we examined the expression of an oncofetal antigen tumor-associated glycoprotein-72 (TAG-72) in prostatic adenocarcinomas with a Gleason grade of six or higher. Using a second generation MAb CC49 against TAG-72, immunoreactivity was detected in 88% (29/33) of the prostatic cancer tissues. Occasionally, the benign epithelium showed a very faint …