Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cathepsin B has been linked to tumor progression through observations that its activity, secretion or membrane association are increased. The most malignant tumors, and specifically the cells at the invasive edge of those tumors, express the highest activity. Cathepsin B may facilitate invasion directly by dissolving extracellular matrix barriers like the basement membrane, or indirectly by activating other proteases capable of digesting the extracellular matrix. Cathepsin B also might play a role in tumor growth and angiogenesis. Cathepsin B activity is the result of several levels of regulation: transcription, post-transcription processing, translation and glycosylation, maturation and trafficking, and inhibition. The majority of reports on cathepsin B expression in tumors have focused on measurements of activity or protein staining. In some tumors, e.g. gliomas, a correlation between the amounts of cathepsin B mRNA, protein and activity and tumor progression has been established. Regulation of cathepsin B at the transcriptional and post-transcriptional levels is still poorly understood. Although the putative promoter regions have characteristics of housekeeping-type promoters, cathepsin B mRNA expression varies depending on the cell type and state of differentiation. We have evidence that more than one promoter could direct expression of human cathepsin B. Multiple transcript species have been detected, resulting from alternative splicing in the 5'- or 3'-untranslated regions, and possibly the use of alternative promoter regions. The existence of transcript variants indicates a potential for post-transcriptional control of expression. In support of this, ras-transformation of MCF-10A human breast epithelial cells results in an increase in protein levels without a concomitant increase in mRNA levels. Cathepsin B mRNA species with distinct 5'- or 3'-untranslated regions may differ in their stability and translatability. Variations in the coding region may also alter cathepsin B properties. We and Frankfater's group have observed transcript species that would encode a truncated protein, lacking the prepeptide and about half of the propeptide. This truncated protein, if synthesized in cells, would be expected to be cytosolic; therefore its function is unclear. Once the several mechanisms of regulation of cathepsin B expression and activity are better understood, they could provide us with new strategies to specifically reduce cathepsin B activity in tumors.
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PMID:Cathepsin B expression in human tumors. 886 Oct 22

Autocrine motility factor (AMF)/phosphoglucose isomerase (PGI) is a ubiquitous cytosolic enzyme and is produced as a leaderless secretory protein, released from cells via a nonclassical pathway. AMF/PGI acts extracellularly as a potent mitogen/cytokine (CXXC, chemokine). Increased expression of AMF/PGI and its receptor/CXXC-R has been found in a wide spectrum of malignancies, and is associated with cancer progression and metastasis. To directly elucidate the functional role of AMF/PGI on cell motility and neoplastic transformation, we stably transfected AMF/PGI cDNA into NIH-3T3 cells. Ectopic overexpression of AMF/PGI results in its secretion and activation via a constitutive autocrine activation loop that renders the cells highly motile, acquiring a transformed phenotype in vitro and tumorigenicity in vivo. The transformed phenotype of AMF/PGI-transfected cells leads in part resistance to induction of apoptosis induced by serum starvation, through the activation of phosphatidylinositol 3'-kinase/Akt signaling pathway and down-regulation of caveolin-1 expression. Overexpression of this housekeeping gene induces resistance to apoptosis and neoplastic transformation, and, thus, AMF/PGI represents a novel class of oncogenic protein.
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PMID:Overexpression of the autocrine motility factor/phosphoglucose isomerase induces transformation and survival of NIH-3T3 fibroblasts. 1251 4

Autocrine motility factor (AMF)/phosphoglucose isomerase (PGI; EC 5.3.1.9) is a housekeeping cytosolic enzyme that plays a key role in both glycolysis and gluconeogenesis pathways. AMF/PGI is also a multifunctional protein that displays cytokine properties, eliciting mitogenic, motogenic, and differentiation activities, and has been implicated in tumor progression and metastasis. Because little is known about AMF/PGI-dependent signaling in general and during tumorigenesis in particular, we sought to study its effect on the cell cycle. To elucidate the functional role of PGI, we stably transfected its cDNA into NIH/3T3 and BALB/c 3T3-A31 fibroblasts. Ectopic overexpression of PGI results in the acquisition of a transformed phenotype associated with an acceleration of G1 to S cell cycle transition. These were manifested by up-regulation of cyclin D1 expression and cyclin-dependent kinase activity and down-regulation of the cyclin-dependent kinase inhibitor p27Kip1. The reduced p27Kip1 protein expression level in PGI-overexpressing cells could be restored to control levels by treatment with proteasome inhibitor. PGI-overexpressing cells also exhibited elevated expression of Skp2 involved in p27Kip1 ubiquitination and elevation in the levels of retinoblastoma protein hyperphosphorylation. Thus, we may conclude that the overexpression of AMF/PGI enhances cell proliferation together with up-regulation of cyclin/cyclin-dependent kinase activities and down-regulation of p27Kip1, whereas the induction of 3T3 fibroblast transformation by PGI is regulated by the retinoblastoma protein pathway.
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PMID:Regulation of cell proliferation by autocrine motility factor/phosphoglucose isomerase signaling. 1278 64

Phosphoglucose isomerase (PGI; EC 5.3.1.9) is a cytosolic housekeeping enzyme of the sugar metabolism pathways that plays a key role in both glycolysis and gluconeogenesis. PGI is a multifunctional dimeric protein that extracellularly acts as a cytokine with properties that include autocrine motility factor (AMF)-eliciting mitogenic, motogenic, and differentiation functions, and PGI has been implicated in tumor progression and metastasis. Little is known of the biochemical regulation of PGI/AMF activities, although it is known that human PGI/AMF is phosphorylated at Ser(185) by protein kinase CK2 (CK2); however, the physiological significance of this phosphorylation is unknown. Thus, by site-directed mutagenesis, we substituted Ser(185) with aspartic acid (S185D) or glutamic acid (S185E), which introduces a negative charge and conformational changes that mimic phosphorylation. A Ser-to-Ala mutant protein (S185A) was generated to abolish phosphorylation. Biochemical analyses revealed that the phosphorylation mutant proteins of PGI exhibited decreased enzymatic activity, whereas the S185A mutant PGI protein retained full enzymatic activity. PGI phosphorylation by CK2 also led to down-regulation of enzymatic activity. Furthermore, CK2 knockdown by RNA interference was associated with up-regulation of cellular PGI enzymatic activity. The three recombinant mutant proteins exhibited indistinguishable cytokine activity and receptor-binding affinities compared with the wild-type protein. In both in vitro and in vivo assays, the wild-type and S185A mutant proteins underwent active species dimerization, whereas both the S185D and S185E mutant proteins also formed tetramers. These results demonstrate that phosphorylation affects the allosteric kinetic properties of the enzyme, resulting in a less active form of PGI, whereas non-phosphorylated protein species retain cytokine activity. The process by which phosphorylation modulates the enzymatic activity of PGI thus has an important implication for the understanding of the biological regulation of this key glucose metabolism-regulating enzyme.
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PMID:Differential regulation of phosphoglucose isomerase/autocrine motility factor activities by protein kinase CK2 phosphorylation. 1563 53

The polymeric immunoglobulin receptor (PIGR) mediates transport of IgA and IgM antibodies across mucosal and glandular epithelia. Several studies have utilized immunohistochemistry to demonstrate that PIGR expression varies in different types of lung carcinoma, and is down-regulated during tumor progression. We have previously shown in cultured tumor cell-lines that basal transcription of the PIGR gene is regulated by the transcription factors USF1, USF2 and AP2. To examine the mechanism by which PIGR expression is down-regulated in lung carcinoma, RNA was microdissected from formalin-fixed, paraffin-embedded lung carcinomas (14 adenocarcinomas and 8 squamous cell carcinomas). Levels of PIGR, USF1, USF2 and AP2-alpha mRNA were quantified by real-time reverse transcriptase-polymerase chain reaction and normalized to mRNA for the housekeeping gene GAPDH. PIGR mRNA levels were decreased in adenocarcinomas and squamous cell carcinomas relative to adjacent non-tumor tissue, and were inversely correlated with stage of differentiation. USF1 and USF2 mRNA levels were reduced in adenocarcinomas relative to non-tumor tissue, while AP2-alpha levels were elevated. Multivariate regression analysis demonstrated that reduced USF2 mRNA and increased AP2-alpha mRNA levels were predictive of down-regulated PIGR mRNA expression in the majority of adenocarcinomas and in moderately differentiated squamous cell carcinomas.
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PMID:Down-regulation of the polymeric immunoglobulin receptor in non-small cell lung carcinoma: correlation with dysregulated expression of the transcription factors USF and AP2. 1586 40

Phosphoglucose isomerase (PGI; EC 5.3.1.9) is a housekeeping cytosolic enzyme of the sugar metabolism pathways that plays a key role in glycolysis and gluconeogenesis. PGI is a multifunctional dimeric protein that extracellularly acts as a cytokine with properties that include autocrine motility factor (AMF) eliciting mitogenic, motogenic, differentiation functions and has been implicated in tumor progression and metastasis. Since metastasis is regulated in part by hypoxia, which induces the transcription of metastasis-associated genes and anaerobic glycolic metabolism, we questioned whether hypoxia also regulates the expression level of tumor cells' PGI/AMF. We establish here that in the human breast carcinoma BT-549 cells hypoxia enhanced expression of the transcription factor hypoxia-inducible factor (HIF)-1, which in turn led to the up-regulation of PGI/AMF expression and was specifically inhibited by inhibitors of the phosphatidylinositol 3'-kinase signaling pathway. In addition, the hypoxia induction of PGI/AMF expression was suppressed by inhibitors of vascular endothelial growth factor (VEGF) or VEGF receptors, suggesting that hypoxia-inducible VEGF regulates the PGI/AMF expression. Hypoxia also enhanced cancer cell motility, and these effects were strongly inhibited by the PGI/AMF, VEGF, or VEGF receptor inhibitors. The results presented here suggest that under hypoxic conditions the expression of PGI/AMF is regulated in part by the HIF pathway, which in turn increases the flow of the glycolytic cascade leading to an increased anaerobic energy generation; thus, inhibition of PGI/AMF expression and activities may provide a new therapeutic modality for treatment of hypoxic tumors.
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PMID:Regulation of phosphoglucose isomerase/autocrine motility factor expression by hypoxia. 1612 9

As for other mRNA measurement methods, quantitative RT-PCR results need to be normalized relative to stably expressed genes. Widely used normalizing genes include beta-actin and glyceraldehyde-3-phosphate dehydrogenase. It has, however, become clear that these and other normalizing genes can display modulated patterns of expression across tissue types and during complex cellular processes such as cell differentiation and cancer progression. Our objective was to set the basis for identifying normalizing genes that displayed stable expression during enterocytic differentiation and between healthy tissue and adenocarcinomas of the human colon. We thus identified novel potential normalizing genes using previously generated cDNA microarray data and examined the alterations of expression of two of these genes as well as seven commonly used normalizing genes during the enterocytic differentiation process and between matched pairs of resection margins and primary carcinomas of the human colon using real-time RT-PCR. We found that ribosomal phosphoprotein P0 was particularly stable in all intestinal epithelial cell extracts, thereby representing a particularly robust housekeeping reference gene for the assessment of gene expression during the human enterocytic differentiation process. On the other hand, beta-2-microglobulin generated the best score as a normalizing gene for comparing human colon primary carcinomas with their corresponding normal mucosa of the resection margin, although others were found to represent acceptable alternatives. In conclusion, we identified and characterized specific normalizing genes that should significantly improve quantitative mRNA studies related to both the differentiation process of the human intestinal epithelium and adenocarcinomas of the human colon. This approach should also be useful to validate normalizing genes in other intestinal contexts.
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PMID:Normalizing genes for quantitative RT-PCR in differentiating human intestinal epithelial cells and adenocarcinomas of the colon. 1639 77

Phosphoglucose isomerase (PGI) is one of the glycolytic enzymes and is a multifunctional enzyme that functions in glucose metabolism inside the cell while acting as a cytokine outside the cell, with properties that include autocrine motility factor (AMF) regulating tumor cell motility. Although there are many studies indicating that PGI/AMF has been implicated in progression of metastasis, no direct studies of the significance of exogenous PGI/AMF on tumor progression have been reported. Here, we report on the mesenchymal-to-epithelial transition (MET), which is the reverse phenomenon of the epithelial-to-mesenchymal transition that is associated with loss of cell polarity, loss of epithelia markers, and enhancement of cell motility essential for tumor cell invasion and metastasis. Mesenchymal human fibrosarcoma HT1080 cells, which have naturally high levels of endogenous and exogenous PGI/AMF, were stably transfected with PGI/AMF small interfering RNA (siRNA). The siRNA targeting human PGI/AMF down-regulated the endogenous PGI/AMF expression and completely extinguished the secretion of PGI/AMF in a human fibrosarcoma HT1080, whereas the control siRNA showed no effects. The PGI/AMF siRNA caused cells to change shape dramatically and inhibited cell motility and invasion markedly. Suppression of PGI/AMF led to a contact-dependent inhibition of cell growth. Those PGI/AMF siRNA-transfected cells showed epithelial phenotype. Furthermore, tumor cells with PGI/AMF deficiency lost their abilities to form tumor mass. This study identifies that MET in HT1080 human lung fibrosarcoma cells was initiated by down-regulation of the housekeeping gene product/cytokine PGI/AMF, and the results depicted here suggest a novel therapeutic target/modality for mesenchymal cancers.
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PMID:Down-regulation of phosphoglucose isomerase/autocrine motility factor results in mesenchymal-to-epithelial transition of human lung fibrosarcoma cells. 1748 35

CpG-oligodeoxynucleotides (CpG-ODN) are potent stimulators of the innate immune system. They promote a Th1-biased immune response with antineoplastic potential. We recently demonstrated antitumoral effects of CpG-ODN in murine transitional cell carcinoma (TCC) models. The purpose of the present work was to more precisely define the immunological nature of this immunotherapeutic approach to TCC.MB-49 TCC was established in female C57/Bl6 mice by intravesical tumor cell instillation after poly-L-lysine conditioning of the bladder (day 0) as described previously. Three groups of six mice were treated: intravesical instillation of 50 microl PBS on days 1, 3, 5, and 7 (group 1, untreated control); 10 nmol CpG 1668 on days 1, 3, 5, and 7 (group 2); and 10 nmol GpC 1668 on days 1, 3, 5, and 7 (group 3). Six native bladders served as no-treatment/no-tumor controls (group 4). Mice were sacrificed on day 11; bladders and draining lymph nodes were removed, and mRNA was prepared for quantitative real-time polymerase chain reaction. Samples were analyzed on a Bio-Rad iCycler for IL 10, TGF-beta, IL 12, and IFNgamma expression; threshold values were compared to beta-actin as housekeeping gene.Tumor take was 100%. Three animals in group 1 had to be sacrificed in advance due to rapid tumor progression. Relative cytokine expression was comparable in groups 1 and 4. IL-10, IL-12, TGF-beta, and IFNgamma were overexpressed in groups 2 and 3. CpG-ODN treatment of murine TCC results in overexpression of both classic Th1 cytokines (IL 12 and IFNgamma) and the Th2 marker IL 10. TGF-beta expression is increased as well. These phenomena are not induced by the growing TCC but by CpG-ODN therapy. They are accompanied by an objective clinical response, as we were able to show recently. Immunostimulatory DNA holds promise to be a novel therapeutic agent in TCC.
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PMID:[Immunostimulatory CpG oligodeoxynucleotides (CpG-ODN) in an orthotopic murine transitional cell carcinoma (TCC) model. Effect on local cytokine expression]. 1867 50

The BRCA/RAD51 complex of tumor suppressor genes plays a major role in the DNA damage response. In this explorative study, BRCA1, BRCA2, and RAD51 mRNA expression was quantified in highly defined laser microdissected tissue samples of simple adenomas, adenocarcinomas of the mammary gland, and their lymph node metastases by real-time quantitative reverse transcription polymerase chain reaction. Expression levels in the tumors were normalized to the geometric mean of 3 housekeeping genes and quantified relative to normal mammary epithelium of the same dog. In adenomas, mRNA expression was reduced for BRCA1 (6/10 dogs, 60%), BRCA2 (4/10 dogs, 40%), and RAD51 (4/10, 40%). In adenocarcinomas BRCA1 expression varied with increased expression in 3 of 10 (30%) dogs and no differences in 7 of 10 (70%) dogs when compared with normal mammary gland. BRCA2 and RAD51 were overexpressed in 5 of 10 (50%) and 6 of 10 (60%) of adenocarcinomas, respectively. An overexpression of RAD51 and BRCA2 was found in 8 of 10 (80%) and 5 of 10 (50%) of the lymph node metastases, respectively. Direct comparison of primary tumors and metastases revealed increased mRNA expression of BRCA1 (2/10 dogs, 20%), BRCA2 (2/10 dogs, 20%), and RAD51 (3/10 dogs, 30%) in lymph node metastases. Taken together, the results suggest that RAD51 is upregulated in the majority of lymph node metastases of canine mammary tumors. Further experimental studies are needed to clarify whether these changes in gene expression are a direct carcinogenetic stimulus or a protective response due to genetic instability during tumor progression.
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PMID:Increased expression of BRCA2 and RAD51 in lymph node metastases of canine mammary adenocarcinomas. 1917 91


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