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疗的显著反应。虽然衰老细胞不分裂，但它们会分泌许多与癌症和其他慢性疾病有关的生物活性蛋白。其中一些蛋白质刺激邻近肿瘤细胞的生长和存活，而另一些则抑制肿瘤细胞的生长和存活。细胞周期蛋白依赖性激酶抑制剂（CDKI）蛋白（如p21/Waf1）的表达，在衰老细胞中经常上调，促进肿瘤促进因子的产生。发现不同类型的衰老正常细胞和肿瘤细胞产生不同的促瘤或抑瘤旁分泌活性。了解衰老细胞的光谱和癌症相关活动的决定因素有助于开发生物标志物和策略，以管理肿瘤衰老对长期治疗结果的影响。在第一个特定目标中，HCT116结肠癌和HT1080纤维肉瘤细胞系将用三种不同的抗癌药物治疗。存活细胞的衰老和增殖部分将通过流动分选分离。这些部分将被用于检测由基因编码的生物活性蛋白的产生和分泌，这些基因是在衰老细胞的RNA水平上诱导的。在第二个特定目标中，衰老肿瘤细胞将被检测影响肿瘤细胞生长、存活、耐药性、侵袭或血管生成的旁分泌活性。在衰老细胞中，旁分泌活性的增加与能够赋予这种活性的蛋白质的分泌有关，这些蛋白质的作用将使用特定的抑制剂进行测试。第三个特定目的是询问抑制cdki激活的转录途径是否会改变衰老肿瘤细胞的分泌模式，从而有利于肿瘤抑制活性。为了进行这项分析，将比较衰老的HCT116细胞及其衍生物在CDKI途径被抑制的情况下的分泌蛋白和旁分泌活性。第四个特定目的是研究在裸鼠中培养的衰老HCT116细胞作为异种移植物并在体内照射使其衰老的生物活性蛋白的产生。此外，异种移植共植入实验将用于研究具有不同CDKI通路状态的衰老HCT116细胞对体内肿瘤生长的影响。该计划应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.