CELL CYCLE REGULATION AND CHEMOSENSITIVITY

我们的研究小组正在利用使能技术来开发 参与进化的分子事件的新兴知识 以破译化疗敏感性的分子基础和癌症 发现新的、更具选择性的化疗药物。当前 重点介绍了(1)等基因模型系统的发展。 从正常人体细胞中提取并研究其生物学和 人类癌症中常见基因改变的药理学影响和(2) 细胞周期通路中抗癌调控元件的研究进展 药物发现。我们目前的研究组合在一定程度上是由 抑癌基因P53在化疗敏感性中作用的研究 (OConnor等，癌症研究，53：4776,1993；Fan等，癌症研究， 54：5824,1994；Fan等，癌症研究，55：1649,1995；Fan等， 癌基因，14：2127,1997)。这些研究最近已经扩展到 NCI抗癌药物筛选的60个细胞系(OConnor等， 癌症研究，57：4285,1997；温斯坦等，科学，275：343,1997) 以及在这项测试中发现的可能利用缺陷p53的药物 目前正在对其活动的作用进行分析。我们现在是 重点研究了基于Normal的体外模型系统的生成 缺乏P53功能的人乳腺上皮细胞及其衍生物 到逆转录病毒传递的显性-阴性突变型p53转基因。 这些研究作为评估其他因素的影响的起点 生物学上常见的人类乳腺癌基因改变 以及正常细胞的药理学。我们还发现，毒品，比如 作为己酮可可碱和UCN-01，优先取消了G2检查站 在p53缺陷的癌细胞中(Fan等人，癌症研究，55：1649， 1995：Wang等人，JNCI，88：956,1996)。我们发现UCN-01 通过缓解Cdc2-2依赖的途径来消除G2停滞 抑制磷酸化。我们排除了Wee1激酶作为一种 UCN-01行动的直接目标。目前的调查包括 UCN-01偶联分子的构效关系研究 与G2/M调控的其他靶点的体外评估 机械设备。正在使用的使能技术包括逆转录病毒基因 递送、微网格DNA阵列、基于多孔的药物分析工具 和高通量生化分析。

Our research group is utilizing enabling technologies to exploit emerging knowledge of molecular events that participate in the evolution of cancer to both decipher the molecular basis of chemosensitivity and to discover new and more selective chemotherapeutic agents. Current emphasis is placed on the (1) development of isogenic model systems derived from normal human cells to study the biological and pharmacological impact of genes commonly altered in human cancer and (2) investigation of control elements in cell cycle pathways for anticancer drug discovery. Our current research portfolio was shaped, in part, by our studies on the role of the p53 tumor suppressor in chemosensitivity (OConnor et al., Cancer Res., 53: 4776, 1993; Fan et al., Cancer Res., 54:5824, 1994; Fan et al., Cancer Res., 55:1649, 1995; Fan et al., Oncogene, 14: 2127, 1997). These studies have recently been extended to the 60 cell lines of the NCI anticancer drug screen (OConnor et al., Cancer Res., 57:4285, 1997; Weinstein et al., Science, 275:343, 1997) and agents identified in this assay that might exploit defective-p53 function for their activity are presently being analyzed. We are now focused on the generation of in vitro model systems based on normal human mammary epithelial cells and derivatives lacking p53 function due to a retrovirally-delivered dominant-negative mutant p53 transgene. These studies act as a starting point to assess the influence of other common genetic alterations seen in human breast cancer on the biology and pharmacology of normal cells. We have also found that drugs, such as pentoxifylline and UCN-01, preferentially abrogated the G2 checkpoint in p53-defective cancer cells (Fan et al., Cancer Research, 55:1649, 1995: Wang et al., JNCI, 88:956, 1996). We have found that UCN-01 abrogates G2 arrest through a Cdc2-dependent pathway by relieving Cdc2- inhibitory phosphorylations. We have excluded the Wee1 kinase as a direct target of UCN-01 action. Current investigations include a structure-activity relationship study of the UCN-01 molecule coupled with in vitro assessment of other targets of the G2/M regulatory machinery. Enabling technologies being used include retroviral gene delivery, microgridded cDNA arrays, multiwell-based drug analysis tools and high-throughput biochemical analysis.