Coukos G, Makrigiannakis A, Kang E H, Rubin S C, Albelda S M, Molnar-Kimber K L
Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Pennsylvania Medical Center, Philadelphia 19104, USA.
Clin Cancer Res. 2000 Aug;6(8):3342-53.
Replication-restricted herpes simplex virus-1 (HSV-1) strains lacking ICP34.5 are emerging as powerful anticancer agents against several solid tumors including epithelial ovarian cancer (EOC). Although chemotherapy-resistant tumors would be likely candidates for treatment with HSV-1 mutants lacking ICP34.5, the efficacy of these mutants on such tumors is unknown. In the present study, we investigated whether chemotherapy resistance affects the response of ovarian cancer cells to HSV-R3616, an ICP34.5-deficient, replication-restricted HSV-1. Primary EOC cultures obtained from patients who varied in their responses to platinum/paclitaxel induction chemotherapy displayed similar sensitivity to HSV-R3616. Similarly, chemotherapy-sensitive ovarian cancer cells A2780 and PA-1, possessing wild-type p53, and their respective chemotherapy-resistant clones A2780/200CP, lacking p53 function, and PA-1/E6, permanently expressing the HPV E6 gene, were equally sensitive to HSV oncolysis. Because wild-type HSV can kill cells by apoptosis and nonapoptotic mechanisms, we investigated the involvement of apoptosis and the role of the p53 tumor suppressor gene in oncolysis induced by HSV-R3616. Infection of ovarian cancer cell lines by HSV-R3616 was followed by cell death via apoptosis or nonapoptotic mechanisms as noted by morphology, cell cycle analysis, and in situ TUNEL assay. p53 protein levels remained unchanged, and Bax protein levels decreased in cells possessing intact p53 and that mainly underwent HSV-induced apoptosis. Loss of p53 function did not affect the frequency or rate of apoptosis or the sensitivity of EOC cells to the oncolytic effect of HSV-R3616. These results suggest that recombinant HSV-1 lacking ICP34.5 is capable of killing ovarian cancer cells that lack p53 function, resist apoptosis, and/or are chemotherapy resistant. These data support the hypothesis that HSV-based oncolytic therapy may be efficacious in chemotherapy-resistant tumors, including tumors that are deficient in p53.
缺乏ICP34.5的复制受限型单纯疱疹病毒1型（HSV-1）毒株正成为针对包括上皮性卵巢癌（EOC）在内的多种实体瘤的强大抗癌剂。尽管化疗耐药肿瘤可能是用缺乏ICP34.5的HSV-1突变体进行治疗的候选对象，但这些突变体对此类肿瘤的疗效尚不清楚。在本研究中，我们调查了化疗耐药性是否会影响卵巢癌细胞对HSV-R3616（一种缺乏ICP34.5、复制受限的HSV-1）的反应。从对铂/紫杉醇诱导化疗反应各异的患者中获得的原发性EOC培养物对HSV-R3616表现出相似的敏感性。同样，具有野生型p53的化疗敏感型卵巢癌细胞A2780和PA-1，以及它们各自缺乏p53功能的化疗耐药克隆A2780/200CP和永久表达HPV E6基因的PA-1/E6，对HSV溶瘤同样敏感。由于野生型HSV可通过凋亡和非凋亡机制杀死细胞，我们研究了凋亡的参与情况以及p53肿瘤抑制基因在HSV-R3616诱导的溶瘤中的作用。HSV-R3616感染卵巢癌细胞系后，通过形态学、细胞周期分析和原位TUNEL检测发现，细胞通过凋亡或非凋亡机制死亡。p53蛋白水平保持不变，而具有完整p53且主要经历HSV诱导凋亡的细胞中Bax蛋白水平下降。p53功能丧失并不影响凋亡的频率或速率，也不影响EOC细胞对HSV-R3616溶瘤作用的敏感性。这些结果表明，缺乏ICP34.5的重组HSV-1能够杀死缺乏p53功能、抗凋亡和/或化疗耐药的卵巢癌细胞。这些数据支持了基于HSV的溶瘤治疗可能对化疗耐药肿瘤（包括p53缺陷肿瘤）有效的假设。
