PKC regulation of salivary acinar cell apoptosis

细胞凋亡的增加或减少可能导致多种疾病的病理学，包括与发育、自身免疫性疾病和癌症相关的疾病。在唾液腺中，细胞凋亡紊乱可能导致唾液腺肿瘤的发生，以及干燥综合征和自身免疫性疾病。此外，在接受头颈部放射或化疗的患者中，正常唾液细胞的凋亡可导致唾液腺功能降低或口干症。了解调节细胞凋亡的机制可能为开发新的治疗方法提供途径，这些治疗方法旨在增强或抑制细胞凋亡。蛋白激酶C（PKC）家族的信号分子由11种异构体组成，其中一些被认为在细胞增殖和细胞死亡中发挥特定作用。本研究的长期目标是了解PKC如何调节唾液腺腺泡细胞凋亡。这里描述的研究将使用原代唾液腺泡细胞的培养物，以及两个分化良好的唾液腺泡细胞系从大鼠腮腺和下颌下腺，探索的假设，激活特定亚型的PKC可以促进或抑制细胞凋亡的化疗药物，X射线照射和FAS配体。我们的初步结果已经确定了唾液腺泡细胞中候选的促凋亡（PKC δ和PKCalpha）PKC亚型。在AIM 1中，我们将确定PKCalpha、PKC β 1和/或PKC δ在经历凋亡的原代唾液细胞中是否被激活。我们将使用PKCalpha和PKC δ的显性负突变体来询问这些亚型的激活是否对细胞凋亡至关重要。AIM 2的研究将集中于了解PKC δ在细胞凋亡过程中是如何被激活的。在AIM 3中，我们将通过表征在凋亡途径中PKC上游和下游起作用的分子来研究促凋亡PKC亚型如何促进凋亡。除了这些研究对唾液腺泡细胞的具体应用外，该模型还代表了一种用于研究上皮细胞凋亡分子机制的替代系统。因此，从这些研究中获得的信息也可能对开发针对其他上皮源性肿瘤（如乳腺癌和胰腺癌）的治疗方法具有重要意义。

An increase or decrease in apoptosis is likely to contribute to the pathology of a wide range of disorders including those associated with development, autoimmune disease and cancer. In the salivary gland, disorders of apoptosis are likely to contribute to the genesis of salivary gland tumors, as well as Sjogren's syndrome, and autoimmune disorder. In addition, the apoptosis of normal salivary cells in patients treated with head and neck irradiation or chemotherapeutics can result in reduced salivary gland function, or xerostomia. Understanding the mechanisms which regulate apoptosis may suggest avenues for the development of novel therapeutics directed at either enhancing or suppressing apoptosis. The protein kinase C (PKC) family of signaling molecules consists of 11 isoforms some of which are thought to play specific roles cell proliferation and cell death. The long-term goal of this proposal is to understand how PKC modulates salivary gland acinar cell apoptosis. The studies described here will use cultures of primary salivary acinar cells, as well as two well differentiated salivary acinar cell lines from the rat parotid and sub-mandibular gland, to explore the hypothesis that activation of specific isoforms of PKC can promote or suppress apoptosis in response to chemotherapeutic drugs, X-irradiation and FAS ligand. Our preliminary results have identified candidate pro-apoptotic (PKCdelta and PKCalpha) PKC isoforms in salivary acinar cells. In AIM 1 we will determine if PKCalpha, PKCbeta1, and/or PKCdelta are activated in primary salivary cells undergoing apoptosis. We will use dominant negative mutants of PKCalpha and PKCdelta to ask if activation of these isoforms is essential for apoptosis. The studies in AIM 2 will focus on understanding how PKCdelta is activated during apoptosis. In AIM 3 we will ask how pro-apoptotic PKC isoforms promote apoptosis by characterizing molecules which function upstream and downstream of PKC in the apoptotic pathway. In addition to the specific application of these studies to salivary acinar cells, this model represents an alternative system in which to study the molecular mechanisms of epithelial cell apoptosis. Thus the information derived from these studies may also have important implications for the development of therapies directed against other epithelial derived tumors such as those of the breast and pancreas.