Secretory Patterns of Senescent Tumor Cells

描述(申请人提供)：诱导细胞衰老是人类肿瘤组织对化疗和放射的显著反应。尽管衰老细胞不会分裂，但它们会分泌许多与癌症和其他慢性病有关的生物活性蛋白。其中一些蛋白质能刺激邻近肿瘤细胞的生长和存活，而另一些蛋白质则能抑制其生长和存活。细胞周期蛋白依赖性激酶抑制因子(CDKI)蛋白(如p21/Waf1)在衰老细胞中表达上调，可促进肿瘤促进因子的产生。不同类型的衰老正常细胞和肿瘤细胞产生不同的促癌或抑瘤旁分泌活性。了解衰老细胞与癌症相关的活动的光谱和决定因素应该有助于开发生物标记物和管理肿瘤衰老对长期治疗结果的影响的策略。在第一个特定目标中，HCT116结肠癌和HT1080纤维肉瘤细胞株将被三种不同的抗癌药物处理。存活细胞的衰老和增殖部分将通过流动分选进行分离。这些组分将被检测以产生和分泌由在RNA水平上诱导的衰老细胞中的基因编码的生物活性蛋白。在第二个特定目标中，将测试衰老的肿瘤细胞的旁分泌活性，这些活性会影响肿瘤细胞的生长、存活、耐药性、侵袭或血管生成。衰老细胞中旁分泌活性的增加将与能够赋予这种活性的蛋白质的分泌相关，这种蛋白质的作用将使用特定的抑制剂进行测试。第三个特定目的是问抑制CDKI激活的转录途径是否改变了衰老肿瘤细胞的分泌模式，有利于肿瘤抑制活动。在这项分析中，将比较HCT116细胞及其衍生物中CDKI途径被抑制的衰老群体的分泌蛋白和旁分泌活性。第四个特定目的是研究在裸鼠体内生长的衰老的HCT116细胞作为异种移植细胞产生生物活性蛋白，并通过体内辐射使其衰老。此外，异种移植共移植实验将被用来研究不同CDKI途径状态的衰老HCT116细胞对体内肿瘤生长的影响。拟议的方案应该有助于阐明肿瘤衰老对癌症治疗结果的不同影响及其对患者健康的长期影响。

DESCRIPTION (provided by applicant): Induction of cell senescence is a prominent response of human tumor tissues to chemotherapy and radiation. Although senescent cells do not divide, they secrete many bioactive proteins implicated in cancer and other chronic diseases. Some of these proteins stimulate while others inhibit the growth and survival of neighboring tumor cells. Expression of cyclin-dependent kinase inhibitor (CDKI) proteins (such as p21/Waf1), which are frequently upregulated in senescent cells, enhances the production of tumor-promoting factors. Different types of senescent normal and tumor cells were found to produce different tumor-promoting or tumor-inhibiting paracrine activities. Understanding the spectra and determinants of cancer-relevant activities of senescent cells should help in developing biomarkers and strategies for managing the impact of tumor senescence on the long-term treatment outcome. In the first specific aim, HCT116 colon carcinoma and HT1080 fibrosarcoma cell lines will be treated with three different anticancer agents. Senescent and proliferating fractions of surviving cells will be separated by flow sorting. These fractions will be assayed for the production and secretion of bioactive proteins encoded by genes that are induced at the RNA level in senescent cells. In the second specific aim, senescent tumor cells will be tested for paracrine activities that affect tumor cell growth, survival, drug resistance, invasion or angiogenesis. Paracrine activities increased in senescent cells will be correlated with the secretion of proteins capable of conferring such activities, and the role of such proteins will be tested using specific inhibitors. The third specific aim asks whether inhibition of the CDKI-activated transcriptional pathway alters the secretory patterns of senescent tumor cells in favor of tumor-suppressing activities. For this analysis, secreted proteins and paracrine activities will be compared between senescent populations of HCT116 cells and their derivatives where CDKI pathway is inhibited. The fourth specific aim investigates production of bioactive proteins by senescent HCT116 cells grown in nude mice as xenografts and rendered senescent by irradiation in vivo. In addition, xenograft coimplantation assays will be used to investigate the effects of senescent HCT116 cells with different CDKI pathway status on tumor growth in vivo. The proposed program should help in elucidating different effects of tumor senescence on the outcome of cancer treatment and on its long-term implications for the patient's health.