Weinrib L, Li J H, Donovan J, Huang D, Liu F F
Department of Experimental Therapeutics, Princess Margaret Hospital/Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada.
Cancer Gene Ther. 2001 May;8(5):352-60. doi: 10.1038/sj.cgt.7700319.
We have previously shown that the introduction of human recombinant wild-type p53 mediated by an adenoviral vector (Ad5CMV-p53), either alone or delivered in combination with ionizing radiation, was cytotoxic to two nasopharyngeal carcinoma (NPC) cell lines. To further explore the potential therapeutic role for gene therapy, the combination of Ad5CMV-p53 and cisplatin was examined in two NPC cell lines, CNE-1 and C666-1. The C666-1 cells are particularly relevant because they express Epstein-Barr virus latent gene products analogous to human NPC in situ. Cells were infected with 5 pfu/cell of Ad5CMV-p53 or Ad5CMV-beta-gal, followed by exposure to increasing doses of cisplatin. Clonogenic and MTT assays were used to assess the sensitivity of cells to these treatments, and apoptosis was also quantified. The combination of Ad5CMV-p53 and cisplatin resulted in approximately 25% greater cytotoxicity compared to that observed with cisplatin alone in either cell line. Apoptosis was induced in approximately 50% of cells following administration of both Ad5CMV-p53 and cisplatin, but was induced in considerably fewer cells following either treatment alone. The two modalities appeared to interact in an additive manner. Ad5CMV-p53 gene therapy resulted in the expression of biologically active p53 protein, shown by induction of p21(WAF1/CIP1). Cisplatin treatment showed little effect on either p53 or p21(WAF1/CIP1) expression. Therefore, both p53 gene therapy and cisplatin chemotherapy demonstrated cytotoxicity mediated by apoptosis despite the presence of EBV gene products in the C666-1 cells, but it appears that the two modalities induce cytotoxicity by independent pathways.
我们之前已经表明，由腺病毒载体（Ad5CMV-p53）介导的人重组野生型p53单独使用或与电离辐射联合使用时，对两种鼻咽癌（NPC）细胞系具有细胞毒性。为了进一步探索基因治疗的潜在治疗作用，我们在两种NPC细胞系CNE-1和C666-1中检测了Ad5CMV-p53和顺铂的联合使用情况。C666-1细胞特别具有相关性，因为它们表达类似于原位人类NPC的爱泼斯坦-巴尔病毒潜伏基因产物。用每细胞5个空斑形成单位（pfu）的Ad5CMV-p53或Ad5CMV-β-半乳糖苷感染细胞，随后暴露于递增剂量的顺铂。使用克隆形成和MTT试验评估细胞对这些处理的敏感性，并对细胞凋亡进行定量分析。与单独使用顺铂相比，Ad5CMV-p53和顺铂的联合使用在任一细胞系中导致的细胞毒性大约高25%。在同时给予Ad5CMV-p53和顺铂后，大约50%的细胞发生凋亡，但单独给予任一处理后诱导凋亡的细胞要少得多。这两种方式似乎以相加的方式相互作用。Ad5CMV-p53基因治疗导致具有生物学活性的p53蛋白表达，这通过p21（WAF1/CIP1）的诱导得以证明。顺铂处理对p53或p21（WAF1/CIP1）的表达几乎没有影响。因此，尽管C666-1细胞中存在EBV基因产物，但p53基因治疗和顺铂化疗均显示出由凋亡介导的细胞毒性，不过这两种方式似乎通过独立的途径诱导细胞毒性。
