Combination of cytosine deaminase with uracil phosphoribosyl transferase leads to local and distant bystander effects against RM1 prostate cancer in mice
Combination of cytosine deaminase with uracil phosphoribosyl transferase leads to local and distant bystander effects against RM1 prostate cancer in mice
复制标题
DOI：
10.1002/jgm.944
复制
发表时间：
2006-09-01
影响因子：
3.5
通讯作者：
Russell, Pamela J.
中科院分区：
文献类型：
--
作者：
Khatri, Aparajita;Zhang, Bing;Russell, Pamela J.
我们的目的是评估基因导向酶-前药疗法（GDEPT）使用胞嘧啶脱氨酶联合尿嘧啶磷酸核糖转移酶（CDUPRT）对免疫活性小鼠前列腺内雄激素难治性前列腺（RM 1）肿瘤的疗效。融合基因CDUPRT的产物将前药5-氟胞嘧啶Martini（5 FC）转化为5-氟尿嘧啶（5 FU）和其他细胞毒性代谢产物，通过“旁观者效应”杀死表达CDUPRT的细胞和周围细胞。为了评估CDUPRT-GDEPT的局部旁观者效应，用5 FC处理前列腺内植入不同比例的RM 1-GFP/CDUPRT和RM 1-GFP细胞的细胞混合物的免疫活性C57 BL/6小鼠。通过尾静脉注射未转染的RM 1细胞建立肺中的假转移。尸检时，评估前列腺重量/体积和肺集落计数。结果用高效液相色谱法（HPLC）检测5 FC酶促转化为5 FU，证实RM 1-GFP/CDUPRT细胞或肿瘤中CDUPRT的表达。用5 FC治疗携带前列腺内RM 1-GFP/CDUPRT肿瘤的小鼠导致肿瘤完全消退。尽管只有20%的细胞表达CDUPRT，但仍观察到“局部旁观者效应”。更重要的是，肺中RM 1细胞假转移的显著减少表明了“远处旁观者效应”。免疫组织化学评价显示，治疗后的肿瘤坏死和凋亡增加，肿瘤血管减少。CDUPRT-GDEPT能显著抑制RM 1前列腺肿瘤的侵袭性生长，并通过免疫机制抑制肿瘤坏死和凋亡，从而抑制肺假转移。版权所有（c）2006约翰威利父子有限公司。
Background We aimed to evaluate the efficacy of gene-directed enzyme-prodrug therapy (GDEPT) using cytosine deaminase in combination with uracil phosphoribosyl transferase (CDUPRT) against intraprostatic mouse androgen-refractory prostate (RM1) tumors in immunocompetent mice. The product of the fusion gene, CDUPRT, converts the prodrug, 5-fluorocytosine Martini(5FC), into 5-fluorouracil (5FU) and other cytotoxic metabolites that kill both CDUPRT-expressing and surrounding cells, via a 'bystander effect'.Methods Stably transformed andogen-independent mouse prostate cancer (PC) cells, RM1-CDUPRT, -GFP or GFP/LacZ cells were used. To assess the local bystander effects of CDUPRT-GDEPT, immunocompetent C57BL/6 mice implanted with cell mixtures of RM1-GFP/CDUPRT and RM1-GFP cells in different proportions intraprostatically were treated with 5FC. Pseudo-metastases in the lungs were established by a tail vein injection, of untransfected RM1 cells. At necropsy, prostate weight/volume and lung colony counts were assessed. Tumors, lymph nodes, spleens and lungs were frozen or fixed for immunohistochemistry.Results CDUPRT expression in RM1-GFP/CDUPRT cells or tumors was confirmed by enzymic conversion of 5FC into 5FU, using HPLC. Treatment of mice bearing intraprostatic RM1-GFP/CDUPRT tumors with 5FC resulted in complete regression of the tumors. A 'local bystander effect' was seen, even though only 20% of the cells expressed CDUPRT. More importantly a significant reduction in pseudo-metastases of RM1 cells in lungs indicated, a 'distant bystander effect'. Immunohistochemical evaluation of the treated tumors showed increased necrosis and apoptosis, with decreased tumor vascularity. There was also a significant increase in tumour-infiltration by macrophages, CD4(+) T and natural killer cells.Conclusions We conclude that CDUPRT-GDEPT significantly suppressed the aggressive growth of RM1 prostate tumors and lung pseudo-metastases via immune mechanisms involving necrosis and apoptosis. Copyright (c) 2006 John Wiley & Sons, Ltd.