Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In addition to infiltrating inflammatory cells, tumors also produce cytokines and growth factors that may alter tumor growth, tumor immunogenicity, and the host immune response. To characterize the expression profile of human non-small cell lung cancer (NSCLC)-derived cytokines, the mRNA expression of type 1 and type 2 cytokines in five human NSCLC lines was analyzed by reverse transcriptase-PCR. Expression of interleukin 5 (IL-5) and IL-10 was demonstrated in all tumor lines evaluated, whereas IL-4 was present in three of five lines and IL-13 was present in two of five lines. In contrast, none of the tumor lines expressed IL-2 and IFN-gamma. Type 2 cytokine protein production by NSCLC lines was confirmed by immunoprecipitation and cytokine specific ELISA. Tumor-derived IL-10 secretion was significantly augmented by exogenous recombinant cytokines including IL-4 and tumor necrosis factor-alpha. To evaluate whether fresh NSCLC nodules also express a type 2 cytokine pattern, the content of type 1 and type 2 cytokines in tissue homogenates from 13 fresh NSCLC nodules and normal lung surgical specimens was assessed. Human NSCLC nodules contain significantly more type 2 cytokines than does normal lung tissue when corrected for total protein concentration. To identify the cellular source of type 2 cytokine production in tumor nodules, immunohistology was performed on sections from 5 lung squamous cell carcinomas and 5 adenocarcinomas. All of the specimens revealed positive staining for type 2 cytokines within tumor cells. In summary, we report that human NSCLC cells produce type 2 cytokines both in situ and in vitro, which may play an active immunoregulatory role in the lung cancer microenvironment.
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PMID:Human non-small cell lung cancer cells express a type 2 cytokine pattern. 764 Dec 3

To ezamine the clinical relevance of P-glycoprotein, encoded by the human multidrug resistance gene (MDR1), to multidrug resistance in lung cancer, we examined the expression of MDR1 in 107 non-small cell lung cancer (NSCLC) specimens and 20 corresponding specimens of normal lung tissues. We also evaluated the relationship between MDR1 expression and the histopathology and pathological staging of NSCLC. The tumors consisted of 60 adenocarcinomas, 38 squamous cell carcinomas, 8 large cell carcinomas, and 1 adenosquamous carcinoma. MDR1 expression was semi-quantified by use of the reverse transcriptase-polymerase chain reaction method. We subclassified the NSCLC into 3 grades according to the MDR1 expression level (-, +, ++). Sixty-one of the 107 tumor specimens (57%) and 18 of the normal lung tissue specimens (90%) expressed various levels of the MDR1 gene. Only one tumor specimen showed higher MDR1 expression than the corresponding normal lung tissue. The relationship between pathological stage and MDR1 expression levels was not significant. These results suggest that the level of MDR1 expression in lung cells is decreased as cells progress from the normal to the transformed state.
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PMID:Expression of the multidrug resistance gene (MDR1) in non-small cell lung cancer. 791 40

Abundant evidence suggests that growth factors are important mediators of non-small cell lung cancer (NSCLC) growth. Although multiple growth factors have been found to be produced by NSCLC tissues, little is known about possible differences in growth factor expression between malignant and adjacent normal lung tissues. Variation in growth factor expression between normal and malignant lung tissues could be potentially useful diagnostically and therapeutically. In studies reported here, the expression of the angiogenic growth factor pleiotrophin (PTN) and homolog midkine (MK) was assessed in resected normal and malignant lung tissues. Primers specific for the two growth factors were used to amplify reverse transcriptase-produced DNA copies of RNA transcripts harvested from the tissues. This analysis revealed that all normal lung tissues examined (n = 17) expressed PTN but only two expressed MK. Conversely, all of the resected lung cancers (n = 20) expressed MK but only one expressed PTN. These results demonstrated a striking reciprocal expression pattern of MK and PTN in normal versus malignant lung tissue.
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PMID:Reciprocal expression of pleiotrophin and midkine in normal versus malignant lung tissues. 821 86

Multidrug resistance-associated protein (MRP) is a 190 kD transmembrane protein and a potentially important drug-transporter protein in human cancers. While the MRP gene is expressed in normal cells and tissues, the expression in solid tumors is not sufficiently determined. MRP and mdr1 mRNA expressions were examined in normal lung parenchyma and in tumor tissues from six small cell lung cancer (SCLC) patients who had received preoperative chemotherapy and eleven nonsmall cell lung cancer (NSCLC) patients. The reverse transcriptase polymerase chain reaction was used. Normal lung tissues and all SCLCs expressed abundant levels of MRP mRNA, while the NSCLCs expressed a wide range of levels from low to high. Most tumor tissues coexpressed both MRP and mdr1, but the levels of mdrl expression was low except in two SCLCs and one NSCLC. MRP is more likely than mdr1 to be one of the clinical multidrug resistance mechanisms found in lung cancer.
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PMID:Multidrug resistance-associated protein (MRP) gene expression in human lung cancer. 871 46

We conducted a feasibility study of continuous etoposide infusion, which was expected to suppress DNA repair after radiation, combined with radiation in patients with advanced non-small cell lung cancer (NSCLC). Between July 1995 and January 1997, 10 patients with NSCLC were registered. Thirty-six mg/m2/day etoposide was infused continuously for a mean of 19 days (range 14-26). Patients tolerated a mean total dose of accelerated hyperfractionated thoracic radiotherapy (1.5 Gy twice per day) of 52.6 Gy (range 33-60). The primary tumors of 7 patients showed partial responses and distant metastasis progression occurred before primary tumor progression in all 7 responders. The hematological adverse effects of chemoradiotherapy were grade 3 or 4 leukopenia in all 10 patients, grade 3 anemia developed in 3, and 2 had grade 3 thrombocytopenia. Six patients contracted infections and one of them died of pneumonia. The major non-hematological adverse effect was esophagitis, which was grade 3 in 3 patients, one of whom died of renal dysfunction. The serum etoposide concentrations were 1.6-2.0 microgram/ml, except in one patient, who had liver dysfunction due to B-type hepatitis. DNA repair gene XRCC1 mRNA expression in peripheral blood mononuclear cells was analyzed, using the reverse transcriptase-polymerase chain reaction, in 8 patients and was suppressed during etoposide infusion in 2. No relationship was observed between serum etoposide concentration and XRCC1 expression and clinical outcome. In conclusion, continuous etoposide infusion combined with thoracic radiation induces severe toxicity and should be given only after careful consideration.
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PMID:A feasibility study of continuous etoposide infusion combined with thoracic radiation for non-small cell lung cancer. 1002 87

The resistance of tumor cells to chemotherapeutic drugs is a major obstacle to successful cancer chemotherapy. Expression of the MDR 1 gene, which encodes for a transmembrane efflux pump (P-glycoprotein), leads to decreased intracellular accumulation and resistance to a variety of anticancer drugs. Recently, one mutant p 53 form was shown to stimulate the MDR 1 gene promoter in vitro, whereas wild-type p 53 repressed this activity. We examined the relationship between p 53 gene mutation and MDR 1 gene expression in specimens from non-small cell lung cancer patients. Tumor samples were obtained from 21 patients during surgery. Mutations of exon 5 through exon 8 of the p 53 gene were detected by the polymerase chain reaction single strand conformation polymorphism method. MDR 1 expression was semi-quantified by the reverse transcriptase polymerase chain reaction method. We identified p 53 gene mutation in samples from 7 patients. MDR 1 gene expression was observed in samples from 20 patients. The expressivity of the MDR 1 gene tended to be higher in patients with adenocarcinoma. No significant relationship between p 53 mutation and MDR 1 expressivity was observed in our study.
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PMID:[Relationship between p 53 gene mutation and MDR 1 gene expression in surgically resected non-small cell lung cancer]. 1070 35

The GML gene (glycosylphosphatidylinositol-anchored molecule-like protein gene) is a novel gene specifically induced by wild-type p53, which may participate in cell cycle control or the cell apoptotic pathway. Recent experiments suggest that the expression of this novel gene in cancer cells is closely associated with sensitivity to certain anticancer drugs. To elucidate the role of the gene expression in cisplatin (CDDP) chemosensitivity of non-small cell lung cancer (NSCLC), 30 surgically resected materials were examined by reverse transcriptase-polymerase chain reaction (RT-PCR). GML gene expression was detected in 9 (30%) samples. Its incidence was significantly higher in immunohistochemically p53-negative (P=0.040) or wild-type p53 tissues (P=0.041). On in vitro chemosensitivity testing using 29 primary tissues, six samples with GML gene expression showed good sensitivity to CDDP. In particular, in tissues with immunohistochemically p53-negative accumulation, those with GML gene expression showed significantly better in vitro sensitivity to CDDP (P=0.012). Clinically a good response to CDDP-based chemo(thermo)therapy for NSCLC patients with tumour residue or recurrence, was observed only in those with p53-negative accumulation and GML gene expression, in agreement with in vitro results. Thus, although the number of tested samples was small, GML gene expression is commonly detected in immunohistochemically p53-negative NSCLCs in close association with good sensitivity to CDDP. GML gene expression analysis may serve as a predictor of CDDP-based chemotherapy for patients with NSCLC.
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PMID:p53-regulated GML gene expression in non-small cell lung cancer. a promising relationship to cisplatin chemosensitivity. 1071 25

Certain drugs used in the treatment of lung cancer and other human malignancies are cytotoxic because of their ability to interact with the two isoforms of topoisomerase II (topo II), topo IIalpha and topo IIbeta. As part of an effort to evaluate the contribution of topo II alterations to drug sensitivity and resistance in lung cancer, we have developed a semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay to measure levels of topo II alpha and beta mRNAs simultaneously using a single pair of primers with sequences common to both isoforms. The PCR products derived from the topo II alpha and beta mRNAs are both 446 bp but have different electrophoretic mobilities in a nondenaturing polyacrylamide gel, allowing sensitive, rapid quantitation when the products are radiolabeled with [35S]-dATP. Using this RT-PCR method, poly(A+) RNA from 13 non-small cell lung cancer (NSCLC) cell lines was analyzed. The results obtained indicated that the cell lines express a wide range of topo II alpha mRNA levels (12-fold) and topo IIbeta mRNA levels (5.5-fold). Tumor and normal lung tissues from 25 patients with NSCLC were also examined. In the tumor samples, the levels of the topo II alpha and beta mRNAs were similar. However, mean topo IIalpha mRNA levels in the tumors were approximately 7-fold higher than those of the paired normal lung tissues. In contrast, topo IIbeta mRNA levels were similar in both tumor and normal lung. Topo II alpha and beta mRNA levels were both significantly lower in the squamous cell tumors than in the adenocarcinoma samples. Topo IIbeta mRNA levels in the squamous cell tumors were also significantly lower than those in paired normal lung tissue. The RT-PCR method described is reliable and convenient, and for the first time, makes the rapid simultaneous direct comparison of topo IIalpha and topo IIbeta mRNA levels feasible in large numbers of clinical samples.
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PMID:Simultaneous quantitation of topoisomerase II alpha and beta isoform mRNAs in lung tumor cells and normal and malignant lung tissue. 1087 30

Cyclooxygenase (COX)-2 has been reported to play an important role in carcinogenesis. Meloxicam (preferential COX-2 inhibitor) inhibits the growth of COX-2 positive and COX-1 negative colorectal cancer cells. We evaluated the effects of meloxicam on the growth of lung cancer cells. By reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis, COX-2 but not COX-1 was expressed in human non-small cell lung cancer (NSCLC) cell lines (A549 and PC14). In human small cell lung cancer (SCLC) cell line (H841), both COX-1 and COX-2 were not detected. MTT assay and prostaglandin (PG) E2 enzyme immunoassay showed that meloxicam inhibited the growth and PGE2 production of both A549 and PC14, but not H841 cells. These findings suggest that COX-2 may play an important role in the pathogenesis and progression of NSCLC, and that meloxicam may be a useful therapeutic agents in the treatment of NSCLC.
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PMID:Meloxicam inhibits the growth of non-small cell lung cancer. 1106 95

The CYFRA 21-1 assay, which detects cytokeratin 19 (CK19) fragment, is widely used as a tumor marker for lung cancer, particularly non-small cell lung cancer. However, the reason that some lung cancer cell lines release CYFRA 21-1 in culture supernatants and others do not remains unclear. We hypothesized that the release of CYFRA 21-1 might be related to the expression of CK19 and caspase 3. In order to prove this, the quantities of mRNA for CK19 were evaluated by the competitive reverse transcriptase-polymerase chain reaction (RT-PCR). CK19 protein synthesis was also evaluated by Western blotting and immunohistochemistry, and the levels of CYFRA 21-1 in the culture supernatant were measured by an immunoradiometric assay. The expression of mRNA for caspase 3 was evaluated by the RT-PCR, and caspase 3 protein synthesis was also evaluated by immunohistochemistry. In 13 lung cancer cell lines, the amounts of mRNA for CK19 correlated with the levels of CYFRA 21-1 in culture supernatants, results of Western blotting for CK19, and positivities of immunohistochemistry for CK19. In 5 cell lines that produced a significant amount of CYFRA 21-1, the level of CYFRA 21-1 correlated with the positivity of RT-PCR for caspase 3 and immunohistochmistry for caspase 3. This suggests that caspase 3 played a role in the formation of CYFRA 21-1. In addition, the specific inhibitor of caspase 3 significantly inhibited the release of CYFRA 21-1 in culture supernatants. In conclusion, we demonstrate that caspase 3, which cleaves several intermediate filaments and carries out cell apoptosis, played an important role in producing CYFRA 21-1 in human lung cancer cell lines.
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PMID:The role of caspase 3 in producing cytokeratin 19 fragment (CYFRA21-1) in human lung cancer cell lines. 1125 67


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