甲状旁腺素对成骨样细胞增殖的调节作用

甲状旁腺素（ＰＴＨ）是调节钙磷代谢的经典激素,有报道ＰＴＨ对其靶细胞－成骨细胞有促增殖分化作用。经多层次、多水平的实验研究证实,ＰＴＨ对成骨样细胞ＲＯＳ１７／２．８确有促增殖作用。（１）细胞计数、ＭＴＴ［３－（４,５－ｄｉｍｅｔｈｙｌｔｈｉａ－ｚｏｌ－ｚ－ｙｉ）２,５－ｄｉｐｈｅｎｙｌｔｅｔｒａｚｏｌｉｕｍｂｒｏｍｉｄｅ］测定及ＳＲＢ（ｓｏｄｉｕｍｒｈｏｄａｍｉｎｅＢ,ＳＲＢ）染色均显示经ＰＴＨ（１０－９ｍｏｌ／Ｌ）处理的细胞,其数目明显增加;（２）３Ｈ－ＴｄＲ参入增加;（３）与增殖相关的原癌基因（ｃ－ｆｏｓ、ｃ－ｊｕｎ、ｃ－ｋｉ－ｒａｓ和ｃ－ｍｙｃ）的表达增强;（４）成骨细胞特征性蛋白－碱性磷酸酶活性降低．这些结果不仅表明该激素具有非经典样作用,同时意味着激素也参与其靶细胞增殖分化的调节作用     

《植物维生素：农学、生理学和营养学领域》

《植物维生素：农学、生理学和营养学领域》（植物维＆素：农＊、＆理学和营养学领域）（ＰｌａｎｔＶｉｔａｍｉｎｓ：ａｇｒｏｎｏｎｌｉｃ,Ｐｈｙｓｉｏｌｏｇｉｃａｌｇｌｉａｌｉｕｔｒｉ－ｉｏｎａｌ。ｐｏｅｔｓ）由Ａ．Ｍｏｚａｆａｒ著,１９９４年ＣＲＣ出版社...     

钝顶螺旋藻C—藻蓝蛋白分子的STM研究

钝顶螺旋藻Ｃ┐藻蓝蛋白分子的ＳＴＭ研究张玉忠＊１,２时东霞１周百成２曾呈奎２庞世瑾１（１中国科学院北京真空物理实验室,北京２７２４信箱,北京１０００８０）（２中国科学院海洋研究所,青岛２６６０７１）关键词钝顶螺旋藻;Ｃ－藻蓝蛋白;扫描隧道显微镜藻胆蛋...     

甲状旁腺素增强成骨样细胞ROS 17/2.8中酪氨酸蛋白磷酸化的研究

为了研究甲状旁腺素（ｐａｒａｔｈｙｒｏｉｄｈｏｒｍｏｎｅ,ＰＴＨ）促成骨样细胞ＲＯＳ１７／２．８增殖分化的信号传递的机理,观察了ＰＴＨ对细胞内酪氨酸蛋白激酶（ｔｙｒｏｓｉｎｅｐｒｏｔｅｉｎｋｉｎａｓｅｓ,ＴＰＫ）活性及酪氨酸蛋白磷酸化水平的影响,并检测了ＰＴＨ对ｃ－ｒａｓｍＲＮＡ表达的诱导作用．结果表明,ＰＴＨ可增强细胞内ＴＰＫ活性,提高细胞内酪氨酸蛋白磷酸化水平,以及促进ｃ－ｒａｓｍＲＮＡ的持续表达．这些结果提示,ＰＴＨ促增殖的细胞内信息传递通路与酪氨酸蛋白激酶－ｒａｓ－ＭＡＰＫｉｎａｓｅ通路密切相关,而ＰＫＡ／ＰＫＣ通路的最终效应可能是通过与上述通路的ｃｒｏｓｓｔａｌｋ实现的     

pp60c-src在血管平滑肌细胞内丝裂原活化蛋白激酶激活中的作用

观察ｐｐ６０ｃ－ｓｒｃ在血管紧张素Ⅱ（ＡｎｇⅡ）诱导血管平滑肌细胞（ＶＳＭＣｓ）内丝裂原活化蛋白激酶（ＭＡＰＫ）激活中的作用,以了解ＡｎｇⅡ促ＶＳＭＣｓ增殖的信号转导过程。将合成的反义ｃ－ｓｒｃ寡脱氧核苷酸（ｏｌｉｇｏｄｅｏｘｙｎｕｃｌｅ－ｏｔｉｄｅｓ,ＯＤＮｓ）以脂质体包裹转染培养的大鼠ＶＳＭＣｓ,用Ｗｅｓｔｅｒｎ印迹测得细胞裂解液中ｐｐ６０ｃ－ｓｒｃ含量明显下降,免疫沉淀方法测得ｐｐ６０ｃ－ｓ     

c－mpl原癌基因编码促血小板生成素受体

ｃ－ｍｐｌ原癌基因编码促血小板生成素受体郭树华,贺福初,吴祖泽（北京放射医学研究所,北京１００８５０）ｃ－ｍｐｌ原癌基因是ｖ－ｍｐｌ（ｍｙｅｌｏＰｒｏｌｉｆｅｒａｔｉｖｅｌｅｕｋｅｍｉａｖｉｒｕｓ,ＭＰＬＶ）的正常细胞的对应物．人的全长ｃ－ｍｐｌｃＤ...     

齿苞筋骨草的化学成分研究

从齿苞筋骨草（Ａｕｊｇａ ｌｕｐｕｌｉｎａ ｖａｒ,Ｍａｊｏｒ）中分离出５个化合物,通过光谱数据鉴定为：６－去乙酰有草素Ⅳ（６－ｄｅａｃｅｌｙｌ ａｊｕａｇｒｉｎ Ⅳ）、香草酸（Ｖａｎｉｌｌｉｅ ａｃｉｄ）、木草素（ｌｕｔｅｌｉｎ）、８－乙酰爪构草甘（８０ａｃｅｔｈｙｌ ｈａｒｐａｇｉｄｅ）和木犀草７－Ｏ－葡萄２糖苷（ｌｕｔｅｌｉｎ－７－Ｏｇｌｕｅｏｐｙｒａｎｏｓｉｄｅ。）     

应用硫氧还蛋白促进外源蛋白在大肠杆菌的可溶性表达

为了观察硫氧还蛋白（ＴｒｘＡ）促进外源蛋白在大肠杆菌中可溶性表达的作用,我们从质粒ｐＥＴ－３２ａ（＋）上克隆了ｔｒｘＡ基因,构建了ＴｒｘＡ表达质粒ｐＴ－ＴｒｘＡ。将该质粒与其它蛋白基因的表达质粒共同转化Ｅ．ｃｏｌｉ并同时获得表达。结果表明,共表达ＴｒｘＡ可以明显促进外源蛋白,如甲状旁腺激素相关蛋白（ＰＴＨｒＰ）、ＰＴＨｒＰ受体（ＰＴＨｒＰ－Ｒ）的血管内皮生长因子（ＶＥＧＦ）的可溶性表达。说明共表达     

一种适用于双向电泳凝胶的染色方法

一种适用于双向电泳凝胶的染色方法＊王台（中国科学院植物研究所,北京１０００９３）ＡＭＥＴＨＯＤＴＯＳＴＡＩＮＴＨＥＧＥＬＯＦＴＷＯ－ＤＩＭＥＮＳＩＯＮＡＬＧＥＬＥＬＥＣＴＲＯＰＨＯＲＥＳＩＳＷａｎｇＴａｉ（ＩｎｓｔｉｔｕｔｅｏｆＢｏｔａｎｙ,Ａｃａｄ...     

细胞信号转导分子在TNF—α诱导c—jun基因表达中的作用

前期研究表明ｐ３８丝裂原活化蛋白激酶（ＭＡＰＫ）通过磷酸化心肌细胞增强因子２（ｍｙｏｃｙｔｅ ｅｎｈａｎｃｅｒ ｆａｃｔｏｒ２,ＭＥＦ２）转录因子家族成员调节ｃ－Ｊｕｎ蛋白表达。ｃ－ｊｕｎ的启动子区存在ＭＥＦ２位点,ＭＥＦ２转录因子家族成员以同源或异源二聚体形式与其结合。研究了ｐ３８和ＢＭＫ１（ｂｉｇ ＭＡＰ ｋｉｎａｓｅ１）在ＴＮＦ－α诱导ｃ－ｊｕｎ基因表达中的调控作用。ｐ３８上调ＭＥＦ２Ａ的转     

Calcitonin-suppressed expression of parathyroid hormone-related protein in breast cancer cells.

Parathyroid hormone-related protein (PTHrP) is a key factor behind humoral hypercalcemia of malignancy (HHM). It is produced in most breast tumors and may be an important local mediator of skeletal metastases due to breast cancer. PTHrP may mediate local bone destruction in the absence of increased circulating PTHrP. Calcitonin (CT) is used for treatment of HHM, but there are data showing that CT can increase PTHrP expression and secretion in vitro. We have therefore studied the effect of CT on PTHrP gene expression and secretion in MCF-7 breast cancer cells. PTHrP mRNA decreased significantly after 4, 8, and 16 h incubation with 10 nM salmon calcitonin (sCT) when compared with the respective controls. PTHrP mRNA also decreased significantly and dose-dependently after incubation with sCT at 0.1 to 10 nM for 16 h. The PTHrP levels in the conditioned medium also decreased in a similar dose-dependent manner. The adenylate cyclase agonist forskolin lowered the PTHrP mRNA dose-dependently. In cells exposed to varying concentrations of sCT for 15 min, the cAMP levels increased dose-dependently. In conclusion, sCT can suppress PTHrP gene expression in MCF-7 breast cancer cells. The suppressive effect is probably exerted mainly via the cAMP-protein kinase A pathways.     

Congenital Craniopharyngioma and Hypercalcemia Induced by Parathyroid Hormone-Related Protein

ObjectiveTo report a case of congenital craniopharyngioma and parathyroid hormone-related protein (PTHrP)-associated humoral hypercalcemia.MethodsDetails of this unusual case are reviewed, from detection of fetal hydrocephalus and a brain tumor, through cesarean delivery at 36 weeks of gestation, to subsequent laboratory studies, management, and confirmation of the diagnosis.ResultsAlthough PTHrP has been well documented as a cause of humoral hypercalcemia of malignancy (HHM) in adult patients with cancer, HHM is uncommon in children. In addition, HHM has rarely been ascribed to nonmalignant tumors. To the best of our knowledge, we report the first case of a neonate with congenital craniopharyngioma and refractory hypercalcemia (peak ionized calcium level of 1.92 mmol/L; normal, 1.05 to 1.3) attributed to an elevated PTHrP value of 8.6 pmol/L (normal, less than 4.7). Intact parathyroid hormone was appropriately undetectable (less than 10 pg/mL; normal, 15 to 65). Despite calcitonin treatment, the hypercalcemia persisted. Although pamidronate infusion stabilized the serum calcium level, the baby did not survive.ConclusionThe diagnosis of craniopharyngioma was confirmed at autopsy, and immunohistochemical studies substantiated that the craniopharyngioma produced PTHrP. (Endocr Pract. 2007;13:67-71)     

Human parathyroid hormone related protein fragment-(1-34) had glucose-6-phosphate dehydrogenase activity on distal convoluted tubules in cytochemical bioassay

In the present study, the action of parathyroid hormone related protein (PTHrP) on glucose-6-phosphate dehydrogenase (G6PD) activity of the distal convoluted tubules was examined utilizing cytochemical bioassay (CBA). Recently full amino acid residues of human PTHrP (hPTHrP), one of the causative agents of HHM, was identified based on the cDNA clone using BEN cells. We synthesized hPTHrP-(1-34) and examined the effect of this protein on G6PD activities on the distal convoluted tubules, and compared its bioactivity to that of human parathyroid hormone (hPTH)-(1-84). hPTHrP-(1-34) stimulated G6PD activity in a log linear fashion with equivalent activity to that of hPTH-(1-84) on a molar basis. Conclusively, we found that PTHrP act on distal convoluted tubules similar to hPTH.     

Humoral hypercalcemia of malignancy

Studies of humoral hypercalcemia of malignancy (HHM) have provided evidence that tumors produce a protein that acts through the parathyroid (PTH) receptor but is immunologically distinct from PTH. We have recently purified and cloned a parathyroid hormone-related protein (PTHrP) implicated in HHM from a human lung cancer cell line (BEN). Full-length cDNA clones have been isolated and found to encode a prepropeptide of 36 amino acids and a mature protein of 141 amino acids. Eight of the first 13 amino-terminal residues are identical with human PTH, although antisera directed to the amino-terminus of PTHrP do not recognize PTH. The striking homology with PTH about the amino-terminal region is not maintained in the remainder of the molecule. PTHrP therefore represents a previously unrecognized hormone. A 34-amino acid synthetic peptide, PTHrP(1-34) was 2-4 times more potent than bovine or human PTH(1-34) in bioassays promoting the formation of cAMP and plasminogen activity in osteogenic sarcoma cells and activation of adenylate cyclase in chick kidney membranes. Like PTH, PTHrP peptides of less than 30 residues from the amino-terminus showed substantially reduced activity. PTHrP(1-34) was also more potent than hPTH(1-34) in stimulating cAMP and phosphate excretion and reducing calcium excretion in the isolated perfused rat kidney. Immunohistochemical localization of PTHrP was consistently demonstrated in squamous cell carcinomas. In normal tissues PTHrP has been immunohistochemically localized in keratinocytes and PTHrP-like activity has been extracted from ovine placenta and fetal ovine parathyroids.(ABSTRACT TRUNCATED AT 250 WORDS)     

Coexpression of PTHrP and PTH/PTHrP receptor in a myoepithelial cell line derived from normal human breast

Parathyroid hormone-related peptide (PTHrP) is the cause of humoral hipercalcaemia of malignancy syndrome (HHM). It is known that the peptide as well as its receptors are widely distributed in many normal organs and tissues, where it influences an array of diverse functions which are realized through paracrine or autocrine pathway. PTHrP is present in large amounts in lactating mammary gland but its function is not fully elucidated. In this study, production of parathyroid hormone-related peptide (PTHrP) by the Hs578Bst cell line corresponding to mammary myoepithelial cells was examined by immunocytochemistry. Using RNA extracted from these cells we analyzed expression of mRNA for PTHrP and for the PTH/PTHrP receptor by RT-PCR. The obtained results demonstrated that Hs578Bst cells produced PTHrP and synthesized mRNA for PTHrP and PTH/PTHrP type I receptor. It provides evidence that myoepithelial cells are target cells for PTHrP. The data support that PTHrP may be an important autocrine/paracrine factor, involved in the regulation of myoepithelial cell function as well as in growth and differentiation of the mammary gland.     

Hypercalcemia in cancer.

Hypercalcemia may occur as a complication of haematological malignancies, in association with solid tumors with bone metastases, and with solid tumors in the absence of bone metastases. The latter syndrome, known as the humoral hypercalcemia of malignancy (HHM) shares many features with primary hyperparathyroidism. A parathyroid hormone-related protein (PTHrP) has been identified, isolated and cloned, which is most likely responsible for the calcium disturbances in HHM, PTHrP is a previously unrecognized hormone which has limited amino-terminal sequence homology with PTH and is the product of a separate gene. Tissue localization studies have identified PTHrP in squamous cell carcinomata, renal cortical carcinomata, in a proportion of breast cancers and in adult T-cell leukemia/lymphoma. In normal tissues, PTHrP has been immunohistochemically localized in keratinocytes, placenta and fetal parathyroid glands. In addition to its role in mediating hypercalcemia in cancer, PTHrP is likely to have an important endocrine role in the fetus, and perhaps a paracrine function in several organs.     

Effects of calcium-sensing receptor on the secretion of parathyroid hormone-related peptide and its impact on humoral hypercalcemia of malignancy

The extracellular calcium-sensing receptor (CaR) plays a key role in the defense against hypercalcemia by "sensing" extracellular calcium (Ca2+(o)) levels in the parathyroid and kidney, the key organs maintaining systemic calcium homeostasis. However, CaR function can be aberrant in certain pathophysiological states, e.g., in some types of cancers known to produce humoral hypercalcemia of malignancy (HHM) in humans and animal models in which high Ca2+(o), via the CaR, produces a homeostatically inappropriate stimulation of parathyroid hormone-related peptide (PTHrP) secretion from these tumors. Increased levels of PTHrP set a cycle in motion whereby elevated systemic levels of Ca2+(o) resulting from its increased bone-resorptive and positive renal calcium-reabsorbing effects give rise to hypercalcemia, which in turn begets worsening hypercalcemia by stimulating further release of PTHrP by the cancer cells. I review the relationship between CaR activation and PTHrP release in normal and tumor cells giving rise to HHM and/or malignant osteolysis and the actions of the receptor on key cellular events such as proliferation, angiogenesis, and apoptosis of cancer cells that will favor tumor growth and osseous metastasis. I also illustrate diverse signaling mechanisms underlying CaR-stimulated PTHrP secretion and other cellular events in tumor cells. Finally, I raise several necessary questions to demonstrate the roles of the receptor in promoting tumors and metastases that will enable consideration of the CaR as a potential antagonizing/neutralizing target for the treatment of HHM.     

Negative regulation of parathyroid hormone-related protein expression by steroid hormones

Elevated parathyroid hormone-related protein (PTHrP) is responsible for humoral hypercalcemia of malignancy (HHM), which is of clinical significance in treatment of terminal patients with malignancies. Steroid hormones were known to cause suppression of PTHrP expression. However, detailed studies linking multiple steroid hormones to PTHrP expression are lacking. Here we studied PTHrP expression in response to steroid hormones in four cell lines with excessive PTHrP production. Our study established that steroid hormones negatively regulate PTHrP expression. Vitamin D receptor, estrogen receptor α, glucocorticoid receptor, and progesterone receptor, were required for repression of PTHrP expression by the cognate ligands. A notable exception was the androgen receptor, which was dispensable for suppression of PTHrP expression in androgen-treated cells. We propose a pathway(s) involving nuclear receptors to suppress PTHrP expression.