MiR-183-96-182 cluster, prostatic zinc homeostasis and carcinogenesis

说明(申请人提供)：锌是一种重要的微量营养素，在细胞中具有结构、催化和调节功能。鉴于锌的多种核心功能，生物体严格调控锌的动态平衡。前列腺独特地浓缩了10倍于其他器官的锌。此外，众所周知，与正常前列腺相比，前列腺癌病变是缺锌的。锌水平与侵袭性疾病呈负相关，饮食中低锌会增加前列腺癌的风险，从而支持锌在前列腺中的保护作用。高水平的锌是维持TH前列腺正常分化状态所必需的，低水平的锌可能会增加去分化，导致前列腺癌的发生或生长。前列腺细胞中的锌缺乏会引起新陈代谢的变化，从而增加细胞的呼吸和细胞的增殖。因此，前列腺癌中锌的减少可能与癌症的病因有关，是一种可行的选择性生物标记物。利用患者标本和原代培养的前列腺细胞，我们最近发现了miR-183、miR-96和miR-182这三个共同表达的microRNAs，它们作为miR-183家族簇一起表达，通过调节几个锌转运体来调节前列腺中锌的动态平衡。MicroRNAs(MiR)是一种小的非编码调控RNA，通过与3‘端非编码区结合来抑制其靶mRNAs的表达。与锌缺乏一致，与来自同一患者的良性上皮相比，前列腺肿瘤中miR-183簇的水平更高。其他研究表明，miRs-183、96和182单独或成簇地在前列腺癌和其他几种癌症中过度表达。MIR簇，如miR-183家族，共表达为单个多顺反子RNA，然后加工成成熟的miR。MIR簇被认为是一种比单一MIR调控更有效地协调复杂细胞过程的机制。综上所述，我们的初步数据表明，miR-183簇是前列腺细胞内锌浓度的调节器。据我们所知，这些数据是第一次报道针对金属运输蛋白家族的miRNA簇。此外，我们和其他人已经发现这个miR簇在前列腺癌中过表达，有力地支持了这个miR簇在癌症发生中的作用。现在 该提案是我们最近数据的扩展，将进一步分析miR-183簇的调节及其在细胞表型、锌隔离、前列腺癌发生和进展中的作用。该项目的结果不仅对前列腺癌有明确的影响，而且对miR-183簇高表达的其他癌症也有明显影响。具体来说，我们将检验以下假设：1)锌在分化的前列腺上皮中的隔离受到miRs-183、96和182作为一个簇的协调表达的调节。2)MIRS-183、96和182是在前列腺癌发生过程中过表达时降低锌水平、促进去分化的癌基因。 与公众健康相关：锌是一种重要的微量营养素，在细胞中具有结构、催化和调节功能。前列腺特别富含锌，而缺锌是前列腺癌的一个标志。这项建议调查了microRNA簇的失调如何通过调节锌稳态而促进前列腺癌的发生。MicroRNAs已成为有吸引力的治疗靶点，因此，了解特定的microRNAs的调节和生理作用是非常必要的。

DESCRIPTION (provided by applicant): Zinc is a vital micronutrient that has structural, catalytic and regulatory functions in cells. Given the diverse and central functions of zinc, organisms tightly regulate zinc homeostasis. The prostate uniquely concentrates zinc 10-fold higher than other organs. Furthermore, it is well established that prostate cancer lesions are zinc depleted compared to normal prostate. Zinc levels inversely associate with aggressive disease and low dietary zinc increases prostate cancer risk, supporting a protective role for zinc in the prostate. High levels of zinc are required to maintain the normal differentiated state of th prostate and lower zinc may increase dedifferentiation and lead to the development or outgrowth of prostate tumors. Zinc depletion in prostate cells causes metabolism changes that increase cellular respiration and cell proliferation. Thus, diminished zinc in prostate cancer may to contribute to the cancer etiology and is a viable selective biomarker for the disease. Using patient specimens and primary prostatic cell cultures we recently identified the microRNAs miR- 183, miR-96 and miR-182, which are expressed as together as the miR-183 family cluster, as regulators of zinc homeostasis in the prostate via regulation of several zinc transporters. MicroRNAs (miR) are small non- coding regulatory RNAs that suppress expression of their target mRNAs via binding to the 3'UTR. Consistent with zinc depletion, higher levels of the miR-183 cluster was present in prostate tumors compared to benign epithelium from the same patients. Others have shown that individually or as a cluster, miRs-183, 96 and 182 are overexpressed in prostate cancer and several other cancers. miR clusters, such as the miR-183 family, are co-expressed as a single polycystronic RNA then processed into the mature miR. miR clusters are thought to exist as a mechanism to more efficiently coordinate complex cell processes than regulation by a single miR can provide. In summary, our preliminary data show that the miR-183 cluster is a regulator of intracellular zinc concentrations in prostate cells. To our knowledge, these data are the first to report a miRNA cluster targeting a family of metal transport proteins. Furthermore, we and others have shown overexpression of this miR cluster in prostate cancer, strongly supporting a role for this miR-cluster in carcinogenesis. The present proposal is an extension of our recent data and will further analyze regulation of the miR- 183 cluster and its role in cell phenotype, zinc sequestration, prostate carcinogenesis and progression. The results of this project will have clear implications not only in prostate cancer, but also in other cancers in which the miR-183 cluster is highly expressed. Specifically we will examine the following hypotheses: 1) Sequestration of zinc in differentiated prostate epithelium is regulated by the coordinated expression of miRs-183, 96 and 182 as a cluster. 2) MiRs-183, 96 and 182 are oncomiRs that reduce zinc levels and promote dedifferentiation when over-expressed during prostate carcinogenesis. PUBLIC HEALTH RELEVANCE: Zinc is a vital micronutrient that has structural, catalytic and regulatory functions in cells. The prostate gland uniquely concentrates zinc and zinc depletion is a hallmark of prostate cancer. This proposal investigates how dysregulation of a microRNA cluster contributes to prostate carcinogenesis by regulation of zinc homeostasis. MicroRNAs have become attractive therapeutic targets and therefore, it is imperative to understand the regulation and physiological role of specific microRNAs.