MONOCYTES TO ASSESS GENOMIC ACTION OF CALCITRIOL

描述(摘自申请人的摘要) 1，25-二羟基维生素D3(1，25(0H)2D3)的生物学效应通过 基因组和非基因组机制。尽管基因组机制起到了一定的作用 在1，25(0H)2D3介导的高钙血症中，非基因组机制，特征 通过增加胃肠道对钙的吸收，可能会有更多 很重要。血、尿钙水平及其他骨标志物 周转率通常用于监测1，25(0H)2D3治疗的患者 因为高钙血症是剂量限制毒性和钙的测试 大多数临床中心都有现成的测量方法。然而， 高钙血症和其他骨转换指标不适合作为特异性标记物 标记因为涉及机制和基因组的双重性质 1，25(0H)2D3的作用与其高钙作用无关。这个 丹参的抗增殖、分化和诱导凋亡作用 1，25(0H)2D3是由基因组反应引起的，可以利用来治疗 以细胞过度增殖为特征的人类疾病 癌症。这就需要识别基因组的特定标记。 1，25(0H)2D3在人体内的作用。 这个项目描述的研究的具体目标是确定 外周血单核细胞可作为组织的代用品。 1，25(0H)2D3在受照患者中的基因组效应评估 每天超过4微克。单核细胞是这些细胞的合适候选者。 研究，因为它们对基因的作用高度敏感 1，25(0H)2D3很容易从其他外周血单核细胞中纯化 细胞，并且可以使用相对简单、非侵入性的方式重复采样 技巧。血液单核细胞中的基因组作用将通过以下方式评估 广为人知的1，25(0H)2D3反应基因的mRNA和酶活性测定 基因：24-羟基酶、胞苷脱氨酶、果糖-1，6-二磷酸酶、 除维生素D外，还有碱性磷酸酶和脂氧合酶 受体)和p21，并与母体药物和 代谢物(用高效液相色谱法测定)。这个 1，25(0H)2D3的基因组作用的多效性 这些酶活性相对缺乏特异性，导致 多个标记物表达的不同时间进程 药品管理局。这些药代动力学：药效学研究将 对1，25(0H)2D3的影响提供新的见解。

DESCRIPTION (Taken from the applicant's Abstract) Biologic effects of 1,25-dihydroxyvitamin D3 (1,25(0H)2D3) are mediated via genomic and non-genomic mechanisms. Although genomic mechanisms play a role in 1,25(0H)2D3-mediated hypercalcemia, non-genomic mechanisms, characterized by increased gastrointestinal absorption of Ca2+, are probably more important. Serum and urinary calcium levels and other markers of bone turnover are routinely used to monitor patients on 1,25(0H)2D3 therapy because hypercalcemia is the dose limiting toxicity and tests for calcium measurement are readily available at most clinical centers. However, hypercalcemia and other bone turnover markers are unsuitable as specific markers because of the dual nature of the mechanisms involved and genomic effects of 1,25(0H)2D3 do not correlate with its hypercalcemic effects. The anti-proliferative, differentiation and apoptosis-induction properties of 1,25(0H)2D3 are due to genomic responses, which can be exploited to treat human diseases characterized by cellular hyperproliferation as seen in cancer. This has led to the need to identify specific markers of genomic action of 1,25(0H)2D3 in humans. This project describes studies whose specific aims are to determine if peripheral blood monocytes can be used as a surrogate tissue in the assessment of genomic effects of 1,25(0H)2D3 in patients receiving doses in excess of 4 micrograms/day. Monocytes are suitable candidates for these studies because they are highly sensitive to the genomic action of 1,25(0H)2D3, are readily purified from other peripheral blood mononuclear cells, and can be sampled repeatedly using relatively simple, non-invasive techniques. The genomic action in blood monocytes will be assessed by measuring mRNA and enzyme activities of well-known 1,25(0H)2D3-responsive genes: 24-hydroxylase, cytidine deaminase, fructose-1,6-diphosphatase, alkaline phosphatase and lipoxygenases, in addition to VDR (a vitamin D receptor) and p21 and related to plasma levels of parent drug and metabolites (measured by high performance liquid chromatography). The pleiotropic nature of the genomic action of 1,25(0H)2D3, together with the relative lack of specificity of these enzyme activities, results in different time courses of multiple markers in their expression relative to drug administration. These pharmacokinetic:pharmacodynamic studies will provide new insight into the effects of 1,25(0H)2D3.