Keshelava N, Seeger R C, Groshen S, Reynolds C P
Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, 90033, USA.
Cancer Res. 1998 Dec 1;58(23):5396-405.
To determine whether neuroblastomas acquire a sustained drug-resistant phenotype from exposure to chemotherapeutic agents given to patients in vivo, we studied neuroblastoma cell lines established at different points of therapy: six at diagnosis before therapy (DX), six at progressive disease during induction therapy (PD-Ind), and five at relapse after intensive chemoradiotherapy and bone marrow transplantation (PD-BMT). Cells were maintained in the absence of drug selective pressure. Dose-response curves of melphalan, cisplatin, carboplatin, doxorubicin, and etoposide for the cell line panel were determined by measuring cytotoxicity with a 96-well-plate digital imaging microscopy (DIMSCAN) microassay. Drug resistance of cell lines progressively increased with the intensity of therapy delivered in vivo. The greatest resistance was seen in PD-BMT cell lines: IC90 values in PD-BMT cell lines were higher than clinically achievable drug levels by 1-37 times for melphalan, 1-9 times for carboplatin, 25-78 times for cisplatin, 6-719 times for doxorubicin, and 3-52 times for etoposide. Genomic amplification of MYCN did not correlate with resistance. Cross-resistance by Pearson correlation (r > or = 0.6) was observed between: (a) cisplatin + doxorubicin; (b) carboplatin + cisplatin, etoposide, or melphalan; (c) etoposide + cisplatin, melphalan, or doxorubicin. These data indicate that during therapy, neuroblastomas can acquire resistance to cytotoxic drugs because of the population expansion of tumor cells possessing stable genetic or epigenetic alterations that confer resistance.
为了确定神经母细胞瘤是否会因在体内接受化疗药物治疗而获得持续的耐药表型，我们研究了在治疗不同阶段建立的神经母细胞瘤细胞系：六个在治疗前诊断时（DX），六个在诱导治疗期间疾病进展时（PD-Ind），以及五个在强化放化疗和骨髓移植后复发时（PD-BMT）。细胞在无药物选择压力的情况下培养。通过96孔板数字成像显微镜（DIMSCAN）微量测定法测量细胞毒性，确定美法仑、顺铂、卡铂、多柔比星和依托泊苷对该细胞系组的剂量反应曲线。细胞系的耐药性随着体内治疗强度的增加而逐渐增强。在PD-BMT细胞系中观察到最大的耐药性：对于美法仑，PD-BMT细胞系中的IC90值比临床可达到的药物水平高1至37倍；对于卡铂，高1至9倍；对于顺铂，高25至78倍；对于多柔比星，高6至719倍；对于依托泊苷，高3至52倍。MYCN的基因组扩增与耐药性无关。通过Pearson相关性（r≥0.6）观察到以下交叉耐药性：（a）顺铂+多柔比星；（b）卡铂+顺铂、依托泊苷或美法仑；（c）依托泊苷+顺铂、美法仑或多柔比星。这些数据表明，在治疗期间，神经母细胞瘤可能会由于具有稳定遗传或表观遗传改变从而赋予耐药性的肿瘤细胞群体扩增而获得对细胞毒性药物的耐药性。
