Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study we describe the activation of a protein kinase which phosphorylates a peptide, T669, comprising amino acids 663-681 of the epidermal growth factor receptor and containing the phosphate acceptor site Pro-Leu-Thr669-Pro. In the human epidermoid carcinoma cell line KB, T669 kinase activity in cytosolic extracts peaked (up to 15-fold compared with basal levels) 15-30 min after addition of interleukin-1 (IL-1) and closely paralleled receptor occupancy with a half-maximally effective concentration of approximately 100 pM IL-1 alpha. IL-1 treatment elevated T669 kinase activity to a variable extent in selected fibroblast lines, the hepatoma cell line HepG2, and the murine thymoma EL4 6.1. An IL-1 receptor-negative EL4 variant and the B cell lines 70Z/3, CB23, and RPMI 1788 did not respond in this way. All of the cell lines except 70Z/3 showed increased levels of T669 kinase when treated with the protein kinase C activator phorbol myristate acetate and/or with epidermal growth factor. This finding is in agreement with a previous study (Countaway, J. L., Northwood, I. C., and Davis, R. J. (1989) J. Biol. Chem. 264, 10828-10835). Activators of protein kinase A did not mimic the ability of IL-1 to stimulate T669 kinase activity, nor did the protein kinase C inhibitor staurosporine abrogate the effect of IL-1. T669 kinase activity from IL-1-stimulated KB cells was partially purified by ion exchange, hydrophobic interaction, and size exclusion chromatography. The partially purified enzyme phosphorylated myelin basic protein, a characteristic substrate of microtubule-associated protein-2 kinase (MAP-2 kinase) and the peptide Arg-Arg-Arg-(Tyr-Ser-Pro-Thr-Ser-Pro-Ser)4 from RNA polymerase II. Western blotting of chromatographic fractions revealed that T669 kinase activity corresponded with two proteins of 43 and 45 kilodaltons which cross-reacted with antibodies raised against peptide sequences of rat extracellular signal-regulated kinase-1/microtubule-associated protein-2 kinase. T669 kinase activity was critically dependent on the presence of phosphatase inhibitors. Since both the 43- and 45-kDa proteins, immunoprecipitated from [32P]phosphate-labeled cells, demonstrated a dramatic increase in their levels of serine, threonine, and tyrosine phosphorylation after brief treatment with IL-1, we conclude that IL-1 modulates the activity of these extracellular signal-regulated kinase/microtubule-associated protein-2 kinases by altering the level of their phosphorylation.
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PMID:Interleukin-1 represents a new modality for the activation of extracellular signal-regulated kinases/microtubule-associated protein-2 kinases. 165 5

Oral squamous cell carcinoma (OSCC) are frequently infiltrated by tumour infiltrating lymphocytes (TILs) which may demonstrate specific anti-tumour cytotoxicity. We have used a panel of family-specific primers in reverse-transcriptase (RT)-polymerase chain reactions (PCR) to determine the TCR Vbeta repertoire of TILs in the primary and metastatic tumours in patients with OSCC. We observed a diverse and heterogenous usage of TCR Vbeta genes by TILs in the primary tumours, a scenario not unlike normal oral mucosal lymphocytes. In one patient with a longstanding history of OSCC, the repertoire was restricted. Restricted TCR Vbeta gene usage also occurred in TILs of metastatic tumours. Within individual patients, discrepancies of TCR Vbeta gene usage were also observed between TILs in the primary OSCC and those in metastatic lymph nodes. Work is ongoing to determine the clonality and functional significance of these TILs.
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PMID:T cell receptor Vbeta repertoire of tumour-infiltrating lymphocytes in oral squamous-cell carcinoma. 862 69

Cancers from patients with tumor-induced hypercalcemia usually produce a circulating factor that mimics the parathyroid hormone activity, termed parathyroid hormone-related protein. Incidence of tumor-induced hypercalcemia appears to be high in patients with squamous cell carcinoma of the esophagus, and the presence of parathyroid hormone-related protein have been shown in some primary esophageal cancers. In the present study, we have investigated the presence of parathyroid hormone-related protein in a patient with metastasized squamous cell carcinoma of the esophagus complicated with tumor-induced hypercalcemia. Protein was searched by immunohistochemistry, and messenger RNA was investigated by reverse transcriptase-polymerase chain reaction and S1 nuclease assay. Both messenger RNA and protein were detected in hepatic metastases, whereas normal esophageal mucosa and primary cancer did not express detectable protein or messenger RNA using the S1 nuclease assay. Reverse transcriptase-polymerase chain reaction was positive in all these tissues, including normal esophageal mucosa. In conclusion, the present case suggests that tumor-induced hypercalcemia due to esophageal squamous cell carcinoma may be caused by parathyroid hormone-related protein mostly released by liver metastases.
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PMID:Parathyroid hormone-related protein in an esophageal squamous cell carcinoma with tumor-induced hypercalcemia. 904 Feb 21

This study aimed to establish patterns of cellular fibronectin mRNA splice variants in normal oral mucosa, oral squamous cell carcinoma, oral leukoplakias with and without atypia, and focal reactive overgrowths of oral mucosa. Particular emphasis was placed on evaluation of either the EDA or EDB domains as markers of malignancy. Total RNA was extracted from normal oral mucosa, oral squamous cell carcinoma, oral leukoplakias with and without atypia, reactive epulides, fibroepithelial polyps and denture-related hyperplasia. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to identify different fibronectin transcripts at three splice sites (EDA, EDB and IIICS). All the tissues investigated produced EDA+, EDA-, EDB+ and EDB- splice variants, and this study did not support RT-PCR-based detection of either EDA or EDB domains as markers of malignancy in oral tissues. Variations in IIICS splice patterns were observed, although these were not specific to any lesion group. In particular, there were differences in either the inclusion or omission of the domain coding for the CS-5 binding site for alpha 4 beta 1 integrin, whereas the CS-1 binding site for alpha 4 beta 1 integrin was typically present when additional domains were included at the IIICS splice site. In conclusion, complex patterns of fibronectin splice variant transcripts exist in normal and pathological oral mucosa. This may reflect the multiple biological functions identified for fibronectin proteins, although the significance of different specific fibronectin splice variants has yet to be fully elucidated.
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PMID:RT-PCR investigation of fibronectin mRNA isoforms in malignant, normal and reactive oral mucosa. 930 23

Pancreatic digestive enzymes have rarely been reported in human nonpancreatic organs. We examined their expression in the epithelial cells of the nonpancreatic gastrointestinal organs, looking for pancreatic alpha-amylase, trypsin, chymotrypsin and pancreatic lipase. Western blotting, enzyme assay and pancreatic alpha-amylase mRNA were also used in selected specimens. In normal tissues, immunoreactivity of one or more of these enzymes was frequently noted in cells of the salivary glands, stomach, duodenum, large pancreatic ducts, extrahepatic bile ducts and gall bladder. The epithelium of the normal oesophagus, small intestine and colon were consistently negative for these enzymes. In pathologic tissues, immunoreactivity for one or more enzymes was present in epithelial cells of pleomorphic adenomas of the salivary glands, oesophageal squamous cell carcinoma, gastric adenoma and adenocarcinoma, pancreatic adenocarcinoma, cholecystitis, adenocarcinoma of the gall bladder and extrahepatic bile duct, and colon adenoma and adenocarcinoma. Western blotting showed a specific band of each enzyme in some specimens of normal stomach. In situ hybridization for pancreatic alpha-amylase mRNA showed specific signals in the normal stomach, but not in the normal colon. Reverse transcriptase polymerase chain reaction analysis for pancreatic alpha-amylase mRNA revealed specific signals in the normal stomach. Enzyme assay revealed that the stomach and gall bladder showed these activities. The data suggest that pancreatic digestive enzymes are produced by several epithelial cell types of the nonpancreatic gastrointestinal organs, that the organs positive for pancreatic enzyme have a common cell lineage, and that neoplasms continue to express or neoexpress these enzymes after neoplastic transformation.
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PMID:Expression of pancreatic digestive enzymes in normal and pathologic epithelial cells of the human gastrointestinal system. 933 41

In this study, human oropharyngeal epidermoid carcinoma KB cells that were resistant to 2,2-difluorodeoxycytidine (dFdCyd) were selected and designated the KB-Gem clone. The KB parental cell line IC50 was 0.3 microM dFdCyd, as compared with the KB-Gem clone IC50 of 32 microM dFdCyd. The KB-Gem clone demonstrated overexpression of ribonucleotide reductase (RR) M2 subunit mRNA (9-fold) and overexpression of M2 protein (2-fold); RR activity was 2.3-fold higher than the KB parental cell line. Both the dATP and dCTP pools of the KB-Gem clone increased 2-fold over the parental cell line, with no change in the dGTP and dTTP pools. Reverse transcriptase-PCR was used to clone the cDNA of deoxycytidine kinase (DCK). Resulting sequences revealed two silent mutations in the KB-Gem clone. The amino acid sequence of the DCK protein and mRNA expression remained unchanged. The KB-Gem clone's DCK enzyme activity was 56% of that of the parental cell line. After the endogenous dNTPs were removed with a G-25 column, no difference was evident between the enzyme activities of the KB-Gem clone and parental cells. Thus, contrary to previous hypotheses, DCK deficiency does not play the primary role in the resistance mechanism of dFdCyd, accepting a secondary role to the overexpression of the target gene, RR, and pool expansion.
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PMID:Overexpression of ribonucleotide reductase as a mechanism of resistance to 2,2-difluorodeoxycytidine in the human KB cancer cell line. 1048 55

A class of less toxic retinoids, called heteroarotinoids, was evaluated for their molecular mechanism of growth inhibition of two head and neck squamous cell carcinoma (HNSCC) cell lines SCC-2 and SCC-38. A series of 14 heteroarotinoids were screened for growth inhibition activity in vitro. The two most active compounds, one that contained an oxygen heteroatom (6) and the other a sulfur heteroatom (16), were evaluated in a xenograph model of tumor establishment in nude mice. Five days after subcutaneous injection of 10(7) SCC-38 cells, groups of 5 nu/nu mice were gavaged daily (5 days/week for 4 weeks) with 20 mg/kg/day of all-trans-retinoic acid (t-RA, 1), 10 mg/kg/day of 6, 10 mg/kg/day of 16, or sesame oil. After a few days, the dose of t-RA (1) was decreased to 10 mg/kg/day to alleviate the side effects of eczema and bone fracture. No significant toxic effects were observed in the heteroarotinoid groups. All three retinoids caused a statistically significant reduction in tumor size as determined by the Student t-test (P < 0. 05). Complete tumor regression was noted in 3 of 5 mice treated with t-RA (1), 4 of 5 mice treated with 16, 1 of 5 mice treated with 6, and 1 of 5 mice treated with sesame oil. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to determine that the expression levels of RARalpha, RXRalpha, and RXRbeta were similar in the two cell lines, while RARbeta expression was higher in SCC-2 over SCC-38, and RARgamma expression was higher in SCC-38 over SCC-2. Receptor cotransfection assays in CV-1 cells demonstrated that 16 was a potent activator of both RAR and RXR receptors, while 6 was selective for the RXR receptors. Transient cotransfection assays in CV-1 cells using an AP-1 responsive reporter plasmid demonstrated that t-RA (1), 6, and 16 each inhibited AP-1-driven transcription in this cell line. In conclusion, the growth inhibition activity of the RXR-selective 6 and the more potent growth inhibition activity of the RAR/RXR pan-agonist 16 implicate both RARs and RXRs in the molecular mechanism of retinoid growth inhibition. Moreover, the chemoprevention activity and the lack of toxicity of heteroarotinoids demonstrate their clinical potential in head and neck cancer chemoprevention.
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PMID:Heteroarotinoids inhibit head and neck cancer cell lines in vitro and in vivo through both RAR and RXR retinoic acid receptors. 1054 87

To examine whether cancer cell dissemination results from incisional biopsy, we tried to detect squamous cell carcinoma (SCC) cells in peripheral blood before and after incisional biopsy by means of cytokeratin 19 (CK19) reverse-transcriptase polymerase chain reaction (RT-PCR). The study population consisted of 20 patients with oral SCC; 10 were given incisional biopsies followed by radical excision (the incisional biopsy group), and the remaining 10 were treated by excisional biopsy alone (the excisional biopsy group). Ten non-oral cancer patients with benign oral lesions served as controls. Five-ml blood aspirates collected before and after incision were used for CK19 RT-PCR. Two (20.0%) of 10 patients from the incisional biopsy group were positive for CK19 transcripts in their peripheral blood drained 15 min after incision. In contrast, CK19 transcript was not detected either in the excisional biopsy group or in controls. Surgical invasiveness for oral cancer, including incisional biopsy, causes dissemination of cancer cells into circulation, resulting in increased risk of metastasis.
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PMID:Dissemination of cancer cells into circulation occurs by incisional biopsy of oral squamous cell carcinoma. 1094 45

To study the role of cytokines that are relevant in cancer cachexia syndrome due to intracerebral tumours, mice were injected with human A431 epidermoid carcinoma, OVCAR3 ovarian carcinoma and GBLF glioma cells comparing intracerebral (i.c.) and systemic (i.p. or s.c.) routes of implantation. Anorexia and weight loss developed within 7-10 days in mice injected i.c. with A431 or OVCAR3 cells well before a large tumour developed, while i.c.-injected GBLF cells did not induce cachexia until day 20, when the tumour was large. By contrast, mice injected i.p. or s.c. developed tumours without evidence of anorexia. Thus, intracerebrally-growing A431 and OVCAR3 resulted in cancer cachexia independent of tumour mass, and we investigated their cytokine pattern. Serum levels of murine and human cytokines are not predictive of cancer cachexia development. Reverse-transcriptase polymerase chain reaction (RT-PCR) analysis revealed in the brain of i.c.-injected A431 tumour-bearing mice expression of human interleukin-(IL-)1alpha, IL-1beta and LIF in all samples and IL-6 in two of four samples while in i.c.-injected OVCAR3 tumour-bearing animals IL-6, and LIF were detected in all samples and tumour necrosis factor-alpha (TNFalpha) in two of four samples. Only LIF was expressed in brains of mice injected with GBLF cells. Murine IL-6 was increased only in the brains of A431-bearing mice. Only mice injected i.c. simultaneously with a monoclonal antibody (mAb) directed against the murine IL-6 receptor and OVCAR3 cells, but not those with mAb and A431 cells, showed a significant increase in survival time with a partial and temporary attenuation of cachexia symptoms. These results suggest that IL-6 in OVCAR3 model may be important cachectogenic factor when centrally released by even a limited number of tumour cells.
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PMID:Role of cytokines in cancer cachexia in a murine model of intracerebral injection of human tumours. 1150 2

A natural animal model for human head and neck squamous cell carcinoma (H/N SCC) has not been described. The domestic cat has a high spontaneous occurrence of oropharyngeal SCC, which is similar to the human disease in aggressiveness and incurability. We have developed a cell line (SCCF1) from a laryngeal SCC of a cat. Keratinocytes were maintained in culture for greater than 50 passages. SCCF1 had strong cytokeratin immunohistochemical staining, weak vimentin staining, and no p53 staining. Ultrastructual features included cytokeratin filaments and desmosomes, as well as features of anaplasia (irregular cytoplasmic and nuclear margins, surface filopodia, and abnormal intermediate filament production). Karyotype analysis revealed aneuploidy, with a stemline chromosomal number of 34. The cells grew logarithmically for 6 d until confluency. SCCF1 expressed parathyroid hormone-related protein (PTHrP) messenger ribonucleic acid (mRNA) and protein, and secreted the protein into the medium. Treatment of SCCF1 with transforming growth factor-beta increased PTHrP production but did not affect PTHrP mRNA stability. Reverse transcriptase-polymerase chain reaction was used to amplify a 282-base pair region of feline PTHrP mRNA, encoding portions of the pre-pro and coding regions. The complementary deoxyribonucleic acid (cDNA) was cloned and sequenced. The cDNA and the predicted amino acid sequences had a high degree of homology to human and canine PTHrP. RT-PCR was used to confirm alternate splicing of PTHrP mRNA for translation of PTHrP 1-139 and PTHrP 1-141. The SCCF1 cell line will permit mechanistic experiments on genetic dysregulation in neoplastic keratinocytes of the feline oropharynx, and development of an in vitro model for H/N cancer.
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PMID:Feline head and neck squamous cell carcinoma cell line: characterization, production of parathyroid hormone-related protein, and regulation by transforming growth factor-beta. 1177 73


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