Salmonella promoters preferentially activated inside tumors
Salmonella promoters preferentially activated inside tumors
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DOI：
10.1158/0008-5472.can-08-0552
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发表时间：
2008-06-15
期刊：
影响因子：
11.2
通讯作者：
McClelland, Michael
中科院分区：
文献类型：
--
作者：
Arrach, Nabil;Zhao, Ming;McClelland, Michael
在动物模型中，肠道沙门氏菌和无毒衍生物更喜欢实体瘤而不是正常组织。鉴定在肿瘤中优先激活的内源性沙门氏菌启动子可以进一步我们对这一现象的理解。为了实现这一目标，一个随机的S。将肠伤寒沙门氏菌14028基因组DNA克隆到编码绿色荧光蛋白（GFP）TurboGFP的无启动子基因的上游。将含有该文库的沙门氏菌群体静脉内注射到无肿瘤裸鼠中和皮下生长在裸鼠中的人PC 3前列腺肿瘤中。2天后，使用荧光激活的细胞分选来富集来自脾或肿瘤的表达GFP的细菌克隆。将所得文库与沙门氏菌基因组的寡核苷酸平铺阵列杂交。发现86个基因间区域在肿瘤样品中富集，但在脾脏中不富集。这些候选启动子中的20个也在来自富集在肿瘤中生长的细菌中表达的文库的100个随机克隆的序列中检测到。在体内分别测试了三个候选启动子克隆，并且证实了相对于脾，在肿瘤中生长的细菌中增强的GFP表达。已知三个克隆中的两个（W和ansB启动子区）在与许多肿瘤相关的缺氧条件下被诱导。对于在肿瘤中生长的细菌中优先诱导的许多其他候选启动子，调节机制可能与缺氧无关。治疗剂在沙门氏菌中在一种或多种在肿瘤中优先激活的启动子的调节下的表达具有改善药物递送的靶向的潜力。
Salmonella enterica and avirulent derivatives prefer solid tumors over normal tissue in animal models. The identification of endogenous Salmonella promoters that are preferentially activated in tumors could further our understanding of this phenomenon. Toward this goal, a random library of S. enterica typhimarium 14028 genomic DNA was cloned upstream of a promoterless gene encoding the green fluorescent protein (GFP) TurboGFP. A population of Salmonella containing this library was injected i.v. into tumor-free nude mice and into human PC3 prostate tumors growing subcutaneously in nude mice. After 2 days, fluorescence-activated cell sorting was used to enrich for bacterial clones expressing GFP from spleens or tumors. The resulting libraries were hybridized to an oligonucleotide tiling array of the Salmonella genome. Eighty-six intergenic regions were found to be enriched in tumor samples but not in spleen. Twenty of these candidate promoters were also detected in the sequences of 100 random clones from a library enriched for expression in bacteria growing in tumors. Three candidate promoter clones were individually tested in vivo, and enhanced GFP expression in bacteria growing in tumor relative to spleen was confirmed. Two of the three clones (W and ansB promoter regions) are known to be induced in hypoxic conditions that pertain to many tumors. For many of the other candidate promoters preferentially induced in bacteria growing in tumors, regulatory mechanisms may not be related to hypoxia. The expression of therapeutics in Salmonella under the regulation of one or more promoters that are activated preferentially in tumors has the potential to improve the targeting of drug delivery.