Persistent enhancement of bacterial motility increases tumor penetration.
Persistent enhancement of bacterial motility increases tumor penetration.
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DOI：
10.1002/bit.25645
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发表时间：
2015-11
影响因子：
3.8
通讯作者：
Forbes NS
中科院分区：
文献类型：
--
作者：
Thornlow DN;Brackett EL;Gigas JM;Van Dessel N;Forbes NS
活动细菌可以克服阻碍许多癌症治疗的运输限制。活性细菌可以穿透组织，将治疗方法传递到耐药的肿瘤区域。然而，细菌治疗取得的成功有限，因为这种运动是异质的，在一个群体中许多个体是不运动的。在人体试验中，异质性导致分散不良和肿瘤定植不完全。为了解决这些问题，提出了一种提高游泳速度的群板选择方法。用视频显微镜测量选定细菌的速度分布，用微流控肿瘤芯片装置测量穿透肿瘤细胞团的能力。在群板上的选择使平均速度增加了4倍，从4.9 μm/sec增加到18.7 μm/sec (P<0.05)，使不运动个体的数量从51%减少到3% （P<0.05）。所选表型既健壮又稳定。不断重复的选择过程提高了速度，淘汰了不动的个体。当选择的菌株冷冻保存和传代30.1倍时，高运动性表型得以保留。在微流控装置中，选择的沙门氏菌比未选择的对照组更深入细胞团。接种10小时后，控制菌聚集在细胞团前30%，最靠近流动通道。相比之下，选定的沙门氏菌聚集在细胞团的后面30%，离通道最远。选择使平均穿透距离从150 μm增加到400 μm （P<0.05）。该技术提供了一种简单、快速的方法来产生高活动性沙门氏菌，具有更高的穿透性和更大的肿瘤分散潜力和临床疗效。
Motile bacteria can overcome the transport limitations that hinder many cancer therapies. Active bacteria can penetrate through tissue to deliver treatment to resistant tumor regions. Bacterial therapy has had limited success, however, because this motility is heterogeneous and within a population many individuals are non-motile. In human trials, heterogeneity led to poor dispersion and incomplete tumor colonization. To solve these problems, a swarm-plate selection method was developed to increase swimming velocity. Video microscopy was used to measure the velocity distribution of selected bacteria and a microfluidic tumor-on-a-chip device was used to measure penetration through tumor cell masses. Selection on swarm plates increased average velocity four fold, from 4.9 to 18.7 μm/sec (P<0.05) and decreased the number of non-motile individuals from 51 to 3% (P<0.05). The selected phenotype was both robust and stable. Repeating the selection process consistently increased velocity and eliminated non-motile individuals. When selected strains were cryopreserved and subcultured for 30.1 doublings, the high-motility phenotype was preserved. In the microfluidic device, selected Salmonella penetrated deeper into cell masses than unselected controls. By ten hours after inoculation, control bacteria accumulated in the front 30% of cell masses, closest to the flow channel. In contrast, selected Salmonella accumulated in the back 30% of cell masses, farthest from the channel. Selection increased the average penetration distance from 150 to 400 μm (P<0.05). This technique provides a simple and rapid method to generate high-motility Salmonella that have increased penetration and potential for greater tumor dispersion and clinical efficacy.