CALMODULIN IN ANDROGEN REGULATION OF PROSTATE CANCER

说明(改编自应用程序) 所有的哺乳动物细胞，包括前列腺上皮细胞， 研究需要多肽生长因子进行增殖。前列腺细胞 增殖还受到雄激素的额外调节。然而，我们非常清楚 对雄激素如何调节细胞增殖知之甚少。 细胞从G1期进入S期依赖于 钙离子和钙调蛋白(CaM)。抑制G1/S边界的CaM，防止 细胞进入S时相。Cam的这一关键角色似乎是 由68 kDa的CaM结合蛋白(CaMBP68)介导。CaMBP68 显示生长因子依赖的移位从细胞质进入 细胞核进入S期，与脱氧核糖核酸紧密结合 DNA所需的复制酶复合体的一个组成部分--聚合酶-α/启动酶 复制。雄激素敏感(LNCaP)前列腺癌细胞也在生长 被抗CaM药物抑制，提示CaM在前列腺中也起着关键作用 癌细胞增殖。此外，雄激素非依赖性(DU145和PC3) 前列腺癌细胞核中CaMBP68的水平明显升高 (与LNCaP细胞相比)，对 CaM拮抗剂的生长抑制作用强于雄激素敏感细胞。 综上所述，这些观察结果使我们假设CaM和CAMBPs 在前列腺癌雄激素调节中发挥重要作用 扩散。 为了验证这一假设，我们将首先确定细胞周期中的时间点 当同步雄激素敏感的进展需要雄激素时 前列腺癌细胞从G1期进入S期再鉴定 在细胞周期的那个时间点，雄激素刺激的事件是由CaM介导的 或CAMBP68。基于之前对雌激素受体的观察，我们将 确定CaM是否对雄激素受体(AR)与 雄激素应答元件(ARE)及其对雄激素应答的表达 基因。因为我们观察到，与雄激素非依赖性细胞相比 雄激素敏感细胞，其体内CaMBP68水平显著升高 由于CaMBP68是复制酶复合体的重要组成部分， 我们将检查复制酶的组装是否有任何差异 这两个细胞系统之间的复合体。阐明其致病机制 雄激素对细胞周期的调节及CaM在雄激素中的作用 这些研究的行动可能为以下方面提供新的见解和机会 控制前列腺癌的细胞增殖和疾病的治疗。

DESCRIPTION (adapted from the application) All mammalian cells, including prostate epithelial cells, that have been studied require polypeptide growth factors for proliferation. Prostate cell proliferation is additionally regulated by androgen. However, we know very little about how androgen regulates cell proliferation. Progression of cells from G1 into S phase is dependent on events regulated by calcium ion and calmodulin (CaM). Inhibition of CaM at G1/S boundary, prevents cells from entering into S phase. This critical role of CaM appears to be mediated by a specific CaM binding protein of 68 kDa (CaMBP68). CaMBP68 exhibits growth factor dependent translocation from the cytoplasm into the nucleus of cells entering into S phase, where it binds tightly to DNA polymerase-alpha/primase, a component of the replitase complex required for DNA replication. Androgen sensitive (LNCaP) prostate cancer cells also are growth inhibited by antiCaM drugs, suggesting a critical role of CaM also in prostate cancer cell proliferation. Moreover, androgen independent (DU145 and PC3) prostate cancer cells have a markedly higher level of CaMBP68 in their nuclei (compared to that in LNCaP cells) and are 6-8 times less sensitive to the growth inhibitory effect of CaM antagonists than are androgen sensitive cells. Taken together, these observations lead us to postulate that CaM and CaMBPs play an essential role in androgen regulation of prostate cancer cell proliferation. To test this hypothesis we will first determine the point in the cell cycle when androgen is required for progression of synchronized androgen sensitive prostate cancer cells from G1 into S phase and then identify whether androgen-stimulated events at that point in cell cycle are being mediated CaM or CaMBP68. Based on earlier observations with the estrogen receptor, we will determine whether CaM is essential for the binding of androgen receptor (AR) to androgen responsive element (ARE) and for the expression of androgen responsive genes. Since we observed that androgen independent cells, as compared to androgen sensitive cells, contain markedly increased levels of CaMBP68 in their nuclei, and since CaMBP68 is an essential component of the replitase complex, we will examine whether there are any differences in the assembly of replitase complexes between these two cell systems. Elucidating the mechanism by which androgen regulates the cell cycle and identifying the role of CaM in androgen action in these studies may provide new insights and opportunities for controlling prostate cancer cell proliferation and treatment of the disease.