Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although there are a number of cell lines committed to differentiate into brown adipocytes, the stem-cell origin of brown fat remains unclear. To address this problem, we explored the effects of various pharmacological agents on differentiation of C3H10T1/2 cells, a pluripotent stem-cell line of mesodermal origin. Histochemical and biochemical analysis revealed that, when these cells were treated with retinoic acid, they expressed the osteoblastic marker alkaline phosphatase. Upon addition of thiazolidinediones and insulin, these cells accumulated lipid and expressed the adipocyte marker aP2, indicating differentiation into adipocytes. Treatment during the growth phase with thiazolidinediones resulted in maximal lipogenesis indicating a need for clonal expansion for efficient adipogenic differentiation. Further analysis revealed that addition of thiazolidinediones to the cells increased (1) the lipolytic response of the cells to beta3-agonists, (2) the expression of uncoupling protein (UCP), (3) the expression of mRNA for type II iodothyronine 5'-deiodinase (5'D-II), and (4) mitochondrial staining. These results suggest the anti-diabetic effects of thiazolidinediones may, in part, involve increased brown adipocyte differentiation. Moreover, this is the first direct evidence indicating that brown adipocytes and osteoblasts may arise from the same stem cell.
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PMID:Thiazolidinediones inhibit alkaline phosphatase activity while increasing expression of uncoupling protein, deiodinase, and increasing mitochondrial mass in C3H10T1/2 cells. 937 45

Thyroid hormone exerts its biological effect by binding to a TR. Both liganded and unliganded TRs regulate the transcription of T(3)-responsive genes. Cofactors with activating or repressing function modulate the transcriptional regulation by TRs. We showed that steroid receptor coactivator 1 (SRC-1)-deficient mice (SRC-1(-/-)) exhibit partial resistance to thyroid hormone at the level of the pituitary thyrotrophs. To determine whether SRC-1 deficiency affects globally T(3)-dependent transcriptional regulation, we studied the effects of thyroid hormone deprivation and replacement on the expression of several genes in different tissues of SRC-1(-/-) and wild-type mice (SRC-1(+/+)). Thyroid hormone deficiency was induced by a low iodine diet (LoI) supplemented with propylthiouracil (PTU) for 2 wk. L-T(3) was injected ip for the last 4 d in one group (PTU+T(3) group), and another group (PTU group) received only vehicle. Levels of mRNAs for T(3)-responsive genes were determined by Northern blotting: GH and TSH beta in pituitary; type 1 iodothyronine 5'-deiodinase, spot 14 (S14), and malic enzyme in liver; and sarcoplasmic reticulum calcium adenosine triphosphatase 2 and myosin heavy chain alpha and beta in heart. Serum parameters, TSH, total cholesterol, creatine kinase, and alkaline phosphatase (AP), were also measured. Hypothyroidism produced a comparable increase in TSH beta mRNA in both genotypes, but its suppression by L-T(3) was attenuated in SRC-1(-/-) mice. In contrast, hypothyroidism failed to reduce S14 mRNA levels in SRC-1(-/-) mice. As a consequence, the response to L-T(3) was not observed in these mice. SRC-1 deficiency had no effect on the expression of the rest of the T(3)-responsive genes examined. Of the four serum parameters, the T(3)-mediated decrease in TSH and changes in AP were attenuated in SRC-1(-/-) mice. We conclude that SRC-1 deficiency altered the expression of only some of the T(3)-responsive genes. SRC-1 appears to be involved not only in transcriptional activation by liganded TRs, but also in the suppression by liganded or unliganded TRs. Some of the effects of SRC-1 may be TR isoform specific.
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PMID:Steroid receptor coactivator-1 deficiency causes variable alterations in the modulation of T(3)-regulated transcription of genes in vivo. 1189 91

Although well-differentiated thyroid carcinomas are usually curable by the combined effects of surgery, radioiodine ablation and thyroid stimulating hormone (TSH) suppressive therapy, recurrence develops in 20-40% of patients. During tumour progression, cellular de-differentiation occurs in up to 30% of cases and is usually accompanied by more aggressive growth, metastasis spread and loss of iodide uptake. The therapeutic options for de-differentiated thyroid cancer are limited and generally not efficient. Retinoic acids (RA) are biologically active metabolites of vitamin A that regulate growth and differentiation of many cell types, by binding to specific nuclear receptors: the retinoic acid receptors (RAR) and the retinoid X receptors (RXR). Recent studies have shown that RA can induce in vitro re-differentiation of thyroid carcinoma cell lines, as suggested by increased expression of the sodium/iodide symporter (NIS), type I iodothyronine deiodinase, alkaline phosphatase and by the increment of cellular (131)I uptake. In addition to re-differentiating effects, RA also exert anti-proliferative actions, as the inhibition of mitosis and the induction of apoptosis. Previous clinical studies have shown that iodide uptake may be re-stimulated after RA in about 20-50% of patients with radioiodine non-responsive thyroid carcinoma. Longer follow-up of patients demonstrated that, besides iodide uptake increment, RA can induce tumour regression or at least tumour growth stabilisation. The therapy is generally well tolerated and the most frequent side effects are dryness of skin and mucosa, and hypertriglyceridemia. This paper describes the recent advances in the field of thyroid cancer therapy and reviews the use of RA as a promising novel therapeutic tool.
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PMID:Tumour re-differentiation effect of retinoic acid: a novel therapeutic approach for advanced thyroid cancer. 1602 5