Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent evidence suggests that tumour necrosis factor alpha (TNF) is an autocrine growth factor for the chronic B-cell malignancies hairy cell leukaemia (HCL) and some cases of B-chronic lymphocytic leukaemia (B-CLL). Incubation with TNF in vitro has been shown to increase viability, DNA synthesis and the expression of the protooncogenes myc, fos and jun in the tumour cells from these patients. TNF in vitro also increases expression of TNF-mRNA, suggesting the existence of an autocrine growth loop for TNF in these cells. Current experiments are compatible with the hypothesis that interferon alpha (IFN) interferes with this autocrine growth loop in HCL and B-CLL by stimulating degradation of messenger RNAs (mRNAs) for a number of cytokines including that of TNF. This RNA degradation may be mediated through induction of the enzyme 2,5 oligo-A synthetase with consequent increased synthesis of 2,5 oligo-A which is known to stimulate the activity of a latent ribonuclease capable of degrading cytokine mRNAs. Circulating tumour-derived TNF may also contribute to the pancytopenia in HCL and B-CLL. Whether cytokine autocrine growth loops are important in other B-cell malignancies, e.g. myeloma and non-Hodgkin's lymphoma, and subject to IFN-stimulated breakdown needs further study.
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PMID:Possible mechanism of action of interferon alpha in chronic B-cell malignancies. 193 2

Expression of the 93-kd tyrosine kinase encoded by the human c-fes proto-oncogene (also known as FES) is restricted to mature hematopoietic cells of the granulocytic and monocytic lineages, suggestive of a function essential to normal myeloid differentiation. However, recent studies have shown that c-fes can transform fibroblasts if sufficient levels of gene expression are achieved. These findings indicate that strict regulation of the c-fes gene is critical to normal myeloid development, whereas elevated c-fes expression may contribute to malignant transformation. In the present study, we compared the c-fes messenger RNA (mRNA) levels in leukemia blasts from patients with myeloid or lymphoid leukemia with those of peripheral monocytes from a normal donor with the use of a quantitative ribonuclease protection assay. The presence of c-fes mRNA was readily detected in both acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) cells, but c-fes mRNA was present in low levels or was absent in lymphoid leukemia cells. The leukemia cells of two of five AML patients and four of four CML patients expressed more c-fes mRNA than monocytes from a normal donor, with more than a threefold elevation in the cells of one CML patient. No evidence of amplification or rearrangement of the c-fes gene was detectable by Southern blot analysis of myeloid leukemia DNA, suggesting that the variation in c-fes mRNA levels are related to differences in transcriptional activity and/or message stability. These results indicate that elevated c-fes expression is a common feature of myeloid leukemia cells that could potentially contribute to the leukemia phenotype.
J Natl Cancer Inst 1991 Jan 02
PMID:Elevated expression of the c-fes proto-oncogene in adult human myeloid leukemia cells in the absence of gene amplification. 198 16

The clinical significance of serum ribonuclease (RNase) was studied in patients with malignant tumor of the ovary, and the result was compared with serum sialic acid (SA). Serum RNase and SA level were determined in 190 women consisting of 35 normal women, 34 patients with ovarian cancer, 39 patients with other malignant gynecological tumors, 38 ovarian cancer patients with clinical remission after treatment and 44 patients with benign gynecological tumor. The sensitivity of serum RNase was 82.4% in the diagnosis of malignant tumor of the ovary. Serum RNase was positive in 42.9% of patients with minimal residual tumor and 88.9% those with residual tumors greater than 2 cm in diameter. Serum RNase assay is a simple, rapid and reliable method useful in monitoring the course of disease.
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PMID:[Serum ribonuclease in patients with malignant tumor of the ovary]. 200 69

Drug resistance is one of the major impediments to the treatment of advanced neuroblastoma. Two neuroblastoma cell lines established from the same patient before (KP-N-AY) and after (KP-N-AYR) chemotherapy are described. Both cell lines were established from bone-marrow metastases of a 2 1/2-year-old patient with stage IV neuroblastoma. Chromosomal analysis, catecholamine assessment and the surface membrane phenotype of these cell lines confirmed that the tumors were of neuroblastoma origin. Compared with the KP-N-AY cell line, the KP-N-AYR line had decreased N-myc amplification but increased N-myc expression. An in vitro sensitivity test using a clonogenic assay showed the KP-N-AYR cell line to be 3.0-fold resistant to adriamycin and 2.7-fold resistant to cis-platinum as compared with the KP-N-AY cell line. The expression of the multi-drug-resistance gene (MDR1) was not observed in either cell line by the ribonuclease protection assay. The KP-N-AY cell line revealed only faint MDR1 RNA by the polymerase chain reaction, whereas the KP-N-AYR cell line had no expression of the MDR1 gene. The level of glutathione-S-transferase-pi was significantly higher in the KP-N-AYR cell line than in the KP-N-AY cell line. These findings suggest that the development of clinical drug resistance may be associated with the enhanced glutathione-S-transferase-pi activity but not with MDR1 gene expression.
Int J Cancer 1991 Mar 12
PMID:Different drug sensitivity in two neuroblastoma cell lines established from the same patient before and after chemotherapy. 200 54

The B lymphoproliferative disorders B chronic lymphocytic leukemia (B-CLL) and hairy cell leukemia (HCL) produce a number of autocrine growth factors, including tumor necrosis factor (TNF), interleukin 6 (IL-6), and IL-1, all of which may induce positive feedback growth loops. If such malignancies depend on these autocrine growth loops for survival, their interruption may be therapeutically valuable. Interferon alpha (IFN-alpha) abrogates TNF- or IL-6-induced proliferation of HCL and B-CLL cells in vitro and has therapeutic activity in these diseases. We have investigated the possibility that IFN-alpha may act by interrupting autocrine growth factor loops. If purified B-CLL or HCL cells are cultured in the presence of TNF, there is induction of mRNA for TNF, IL-1 alpha, IL-1 beta, and IL-6. However, culture in the presence of IFN-alpha in addition to TNF reduced the level of mRNA for all these cytokines, compared with cells cultured in TNF alone. While cytokine mRNA levels were diminished, levels of mRNA for the ribonuclease activator 2-5A synthetase were increased. Analysis of the kinetics of cytokine mRNA production showed that levels fall shortly after the rise of 2-5A synthetase mRNA. IFN-alpha may produce these effects by shortening the half-life of cytokine mRNA, since TNF mRNA half-life in B-CLL and HCL cells is substantially reduced when the cells are cultured with IFN-alpha. These data suggest that IFN-alpha may mediate its therapeutic effects in these malignancies by blocking autocrine growth factor loops.
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PMID:Effects of interferon alpha on autocrine growth factor loops in B lymphoproliferative disorders. 225 3

The human MDR1 gene encoding P-glycoprotein, an energy-dependent drug-efflux pump, was initially isolated from a multidrug-resistant KB carcinoma cell. When a 3 kb genomic sequence isolated from normal human tissue including the major downstream promoter and the first and second exons of the MDR1 gene was compared to the equivalent fragment from KB cells, the MDR1 gene from KB carcinoma cells was found to have a point mutation in the first exon. Although this mutation does not affect the downstream promoter sequence or the coding sequence of the MDR1 gene, it creates a single base mismatch between the 5' KB genomic fragment previously used for RNase protection analysis of MDR1 RNA expression in normal tissues and thereby reduces the sensitivity of this assay. Using the DNA fragment from normal tissues rather than KB cells, we have reanalyzed MDR1 mRNA levels in 12 renal carcinomas and 4 colon adenocarcinomas. By this RNase protection assay, MDR1 RNA levels are as high in these tumors as in the multidrug-resistant cell line, KB-8-5. The ribonuclease protection assay indicated that the major downstream promoter was mainly used in these clinical samples including two samples of RNA from metastatic renal cancer. This assay appears to be a very sensitive and specific assay for detecting MDR1 mRNA levels and mRNA initiation sites in clinical samples.
Jpn J Cancer Res 1989 Nov
PMID:Detection of multidrug resistance (MDR1) gene RNA expression in human tumors by a sensitive ribonuclease protection assay. 248 65

Magnetic resonance spectroscopy (MRS) can identify abnormal lipoproteins in the plasma of patients with premalignant and malignant tumours. Proteolipid complexes, 8-11 nm and 25-28 nm in size, were isolated from the plasma of a patient with a borderline ovarian tumour. These complexes, which generated a characteristically long MRS T2 relaxation value (greater than 400 ms), were disrupted by ribonuclease. None of the conventional lipoproteins had a T2 value above 160 ms. Chemical analysis of the proteolipid complexes showed a 20% glycolipid component, and MRS identified a fucosylated molecule as the origin of the long T2 value. 9 months after resection of all tumour, a visible lipoprotein band, possibly lipoprotein (a), persisted in the plasma but neither the long T2 relaxation value nor the 8-11 nm or 25-28 nm particles were present. The long T2 relaxation value in the MRS profile, found in isolated proteolipid and unfractionated plasma and serum of other patients with carcinoma of the ovary and colon, provides a non-invasive method of assaying for cancer.
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PMID:Proteolipid identified by magnetic resonance spectroscopy in plasma of a patient with borderline ovarian tumour. 288 35

The influence of a variety of clinical and biochemical parameters on the activities in serum of ribonuclease (RNAse) selective for polycytidylic acid (RNAse C) were examined in 90 adult patients with cancer. The clinical data base determined on each patient included: RNAse C level, carcinoembryonic antigen (CEA) level, age, sex, race, presence (or absence of metastases, type of cancer, site of metastasis, renal function blood urea nitrogen [BUN], creatinine), hepatic function (bilirubin, alkaline phosphatase), and nutritional status (percent ideal body weight, percent weight loss, and albumin). Common tumor types studied included: colon (21), lung (18), breast (15), and hepatocellular carcinoma (10). For comparison, 175 nonmalignant control patients were studied to establish the normal range for RNAse. In patients with cancer, RNAse levels were increased in 57% and CEA levels were above 10 ng/dl in 36%. Although patients with BUN greater than 25 mg/dl or creatinine greater than 1.5 mg/dl were not entered on the study, nonetheless, RNAse was significantly (P less than 0.05) associated with both BUN and creatinine. Nutritional status also had an important influence on RNAse levels as both percent weight loss and percent ideal body weight were significantly (P less than 0.05) associated with circulatory RNAse: weight loss resulted in higher RNAse levels. These results account in part for the increased RNAse levels seen in those malignant conditions such as pancreatic and lung cancer commonly associated with weight loss in advanced stage. The possibility that circulatory RNAse C determination will provide a sensitive means for assessing nutritional status in cancer patients will require prospective evaluation.
Cancer 1985 Jan 15
PMID:Influence of nutritional status on circulatory ribonuclease C levels in patients with cancer. 298 Nov 45

Human poly (C) avid serum ribonuclease (RNase) differs in physico-chemical, electrophoretic, and catalytic properties from ribonuclease activity encountered in liver preparations. The first is reported as "secretory type", the latter, because it is undetectable in body fluids, as "nonsecretory type". We determined RNase activity in 11 hepatoma patients. A statistical difference from a normal control of corresponding age was encountered in both age groups investigated (51-60 years, P less than 0.05; 61-70 years, P less than 0.01). The circumstances mentioned above make the tumor itself unlikely to be the source of RNase elevation. Besides a diminished synthesis of RNase inhibitor by hepatoma cells, tumor-derived polyamines could contribute to enhanced RNase activity. The influence of polyamines on RNase activity has already been demonstrated by in vitro experiments. Simultaneous estimation of polyamines and RNase is required to elucidate in vivo circumstances.
Cancer Detect Prev 1987
PMID:Estimation of poly (C) avid serum ribonuclease in hepatoma patients. 303 38

Retinoblastoma (RB) is a malignant tumor of developing retina that arises when abnormalities resulting in loss of function affect both alleles of the gene at the retinoblastoma locus (RB1) on chromosome 13q. The majority of RB tumors do not show gross alterations in a 4.7-kb fragment (4.7R), which is a candidate RB1 gene. To search for more subtle mutations, the ribonuclease protection method was used to analyze 4.7R messenger RNA from RB tumors. Five of 11 RB tumors, which exhibit normal 4.7R DNA and normal-sized RNA transcripts, showed abnormal ribonuclease cleavage patterns. Three of the five mutations affected the same region of the messenger RNA, consistent with an effect on splicing involving an as yet unidentified 5' exon. The high frequency of mutations in 4.7R supports the identification of 4.7R as the RB1 gene. However, the unusual nature of some of the abnormalities of 4.7 R alleles indicates that the accepted sequence of genetic events involved in the genesis of RB may require reevaluation.
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PMID:Identification of germline and somatic mutations affecting the retinoblastoma gene. 317 21


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