Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029463 (osteosarcoma)
 16,637 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In man, there are multiple forms of alkaline phosphatase encoded by at least three homologous genes: placental, intestinal, and liver/bone/kidney. This report describes the characterization of the human liver/bone/kidney alkaline phosphatase locus. The gene appears to exist as a single copy in the haploid genome and is comprised of 12 exons distributed over more than 50 kilobases. In liver, kidney, SAOS-2 human osteosarcoma cells, and cultured fibroblasts, there is a single major start for transcription situated about 25 nucleotides downstream of an A/T-rich motif. The promoter region is extremely G/C-rich, is relatively abundant in the dinucleotide CpG, and contains four copies of the consensus sequence for SP1 binding (GGGCGG). The liver/bone/kidney alkaline phosphatase gene is at least five times larger than the intestinal and placental alkaline phosphatase genes, mainly due to intron size differences. Intron-exon junctions occur at analogous positions in all three genes, but there is an extra non-coding exon at the 5' end of the liver/bone/kidney alkaline phosphatase gene. The relevance of our findings with respect to the evolution of the human alkaline phosphatase multigene family is discussed.
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PMID:Structure of the human liver/bone/kidney alkaline phosphatase gene. 316 80

In 1930 the determination of serum alkaline phosphatase in patients with bone or liver disease ushered in the era of clinical enzymology. The association of elevated (bone) alkaline phosphatase in serum of patients with osteogenic sarcoma was the first evidence that tumor cells themselves produced the enzyme. It became clear, however, in the 1960s that the serum alkaline phosphatase was not a single enzyme but consisted of a family of isozymes originating from liver, bone, intestine, and placenta. This was a consequence of the introduction of a combination of electrophoretic separations, heat inactivation, and organ-specific amino acid inhibitors. This combination of measurements made possible the demonstration of a serum alkaline phosphatase of lung cancer origin, as confirmed by the histochemical visualization in lung cancer of the Regan Isozyme (placental alkaline phosphatase-PLAP). At present, the measurement of PLAP has its greatest utility as a tumor marker in seminoma and ovarian cancer. A PLAP-like isozyme in normal testis and ovary is expressed in these and other neoplasias and appears to be related to rare alleles of placental alkaline phosphatase. Current studies have utilized a panel of monoclonal antibodies to detect useful epitopes that suggest that PLAP and PLAP-like isozymes are coded by different genes. The PLAP gene has now been cloned and sequenced by Millan and others. This fundamental new information is providing a base line that will make it possible to explain the overlapping specificities of intestinal and placental isozymes, the degree of uniqueness of the PLAP-like isozyme, the precise mechanism of uncompetitive inhibition by L-phenylalanine and the evolutionary history of the alkaline phosphatases.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Clinical and biological significance of an isozyme tumor marker--PLAP. 332 92

The specific activity of alkaline phosphatase was increased in two human osteogenic sarcoma cell lines, SAOS and TE85, after treatment with 1,25 dihydroxy-vitamin D3 (1,25(OH)2D3). Enzyme activity increased when the cells were incubated with concentrations of 1,25(OH)2D3 between 10(-9) and 10(-7) M and cell growth was not inhibited at these concentrations. The specific activity of alkaline phosphatase was 4- to 7-fold higher than that in the control cells after 5 to 7 days of continuous exposure to 1,25(OH)2D3. Immunochemical studies demonstrated that the enzyme from both control and 1,25(OH)2D3-treated cultures cross-reacted with antisera specific for the phosphatase isoenzyme produced by normal human bone, and did not cross-react with antisera specific for the placental alkaline phosphatase isoenzyme. The increased enzyme activity in cultures induced with 1,25(OH)2D3 correlated with an absolute increase in the number of bone-specific phosphatase molecules, as determined by radioimmunoassay. No effect on alkaline phosphatase activity was observed when the cells were treated with other vitamin D metabolites or with 5-bromo-2'-deoxyuridine. Comparative studies demonstrated that hydrocortisone, another steroid hormone, increased the phosphatase activity with a different time course than did 1,25(OH)2D3. High affinity cytoplasmic receptors for 1,25(OH)2D3 and hydrocortisone were found in the SAOS and TE85 cells.
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PMID:1,25-Dihydroxyvitamin D3 increases bone alkaline phosphatase isoenzyme levels in human osteogenic sarcoma cells. 618 22

We report here on the construction and use of a novel human immunodeficiency virus (HIV) type 1 reporter vector, HIV-AP, that encodes human placental alkaline phosphatase. Upon staining with chromogenic alkaline phosphatase substrates 24 to 36 h postinfection, cells infected with HIV-AP develop an intense purple color and can then be counted under a dissecting microscope. Alternatively, HIV-AP infectivity can be quantitated and infected cells can be sorted by a fluorescence-activated cell sorter after staining with a fluorescent alkaline phosphatase substrate. The assay is rapid and accurate, has very low background in a variety of cell lines and primary cells, and is not restricted to use in human cells. Infectious HIV-AP can be pseudotyped by various HIV or murine leukemia virus envelope glycoproteins. Using this virus, we have addressed the long-standing question of CD4-independent infection of cells by HIV. Our results confirm the presence on a human osteosarcoma cell line of an alternative receptor for HIV infection that functions with an efficiency approximately 1/20 that of CD4.
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PMID:Use of a novel human immunodeficiency virus type 1 reporter virus expressing human placental alkaline phosphatase to detect an alternative viral receptor. 776 29

In the pituitary of mammals, the GnRH receptor (GnRHR) plays a primary role in the control of reproductive function. It is further expressed in the hippocampus, where its function, however, is not well defined. By quantitative RT-PCR analyses, we demonstrate herein that the onset of GnRHR gene (Gnrhr) expression in the rat hippocampus was unexpectedly delayed as compared to the pituitary and only occurred after birth. Using a previously described transgenic mouse model bearing the human placental alkaline phosphatase reporter gene under the control of the rat Gnrhr promoter, we established a positive correlation between the temporal pattern of Gnrhr mRNA levels and promoter activity in the hippocampal formation. The gradual appearance of human placental alkaline phosphatase transgene expression occurred simultaneously in the hippocampus and interconnected structures such as the lateral septum and the amygdala, coinciding with the establishment of hippocampo-septal projections. Analysis of transcription factors together with transient transfection assays in hippocampal neurons indicated that the combinatorial code governing the hippocampus-specific expression of the Gnrhr is distinct from the pituitary, likely involving transactivating factors such as NUR77, cyclic AMP response element binding protein, and Finkel-Biskis-Jinkins murine osteosarcoma virus oncogene homolog. A silencing transcription factor acting via the -3255/-1135 promoter region of the Gnrhr may be responsible for the transcriptional repression observed around birth. Finally, GnRH directly stimulated via activation of its receptor the expression of several marker genes of neuronal plasticity such as Egr1, synaptophysin, and spinophilin in hippocampal primary cultures, suggesting a role for GnRHR in neuronal plasticity. Further characterization of these mechanisms may help unravel important functions of GnRH/GnRHR signaling in the brain.
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PMID:GnRH receptor gene expression in the developing rat hippocampus: transcriptional regulation and potential roles in neuronal plasticity. 2112 36