Platform technologies based on plant virus nanoparticles (VNPs) and virus-like particles (VLPs) are attracting the attention of researchers and clinicians because the particles are biocompatible, biodegradable, noninfectious in mammals, and can readily be chemically and genetically engineered to carry imaging agents and drugs. When the Physalis mottle virus (PhMV) coat protein is expressed in Escherichia coli, the resulting VLPs are nearly identical to the viruses formed in vivo. Here, we isolated PhMV-derived VLPs from ClearColi cells and carried out external and internal surface modification with fluorophores using reactive lysine-N-hydroxysuccinimide ester and cysteine-maleimide chemistries, respectively. The uptake of dye-labeled particles was tested in a range of cancer cells and monitored by confocal microscopy and flow cytometry. VLPs labeled internally on cysteine residues were taken up with high efficiency by several cancer cell lines and were colocalized with the endolysosomal marker LAMP-1 within 6 h, whereas VLPs labeled externally on lysine residues were taken up with lower efficiency, probably reflecting differences in surface charge and the propensity to bind to the cell surface. The infusion of dye and drug molecules into the cavity of the VLPs revealed that the photosensitizer (PS), Zn-EpPor, and the drugs crystal violet, mitoxantrone (MTX), and doxorubicin (DOX) associated stably with the carrier via noncovalent interactions. We confirmed the cytotoxicity of the PS-PhMV and DOX-PhMV particles against prostate cancer, ovarian and breast cancer cell lines, respectively. Our results show that PhMV-derived VLPs provide a new platform technology for the delivery of imaging agents and drugs, with preferential uptake into cancer cells. These particles could therefore be developed as multifunctional tools for cancer diagnosis and therapy.

中文翻译：

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空泡斑驳病毒样颗粒作为用于成像试剂和药物的纳米载体

基于植物病毒纳米颗粒（VNP）和病毒样颗粒（VLP）的平台技术吸引了研究人员和临床医生的注意，因为这些颗粒具有生物相容性，可生物降解性，在哺乳动物中无感染性，并且可以通过化学和基因工程轻松地携带显像剂和毒品。当空泡斑驳病毒（PhMV）外壳蛋白在大肠杆菌中表达时，所得的VLP与体内形成的病毒几乎相同。在这里，我们从ClearColi细胞中分离了PhMV衍生的VLP，并使用反应性赖氨酸N对荧光团进行了外部和内部表面修饰-羟基琥珀酰亚胺酯和半胱氨酸-马来酰亚胺化学。在一系列癌细胞中测试了染料标记颗粒的摄取，并通过共聚焦显微镜和流式细胞术对其进行了监测。内部标记在半胱氨酸残基上的VLP被几种癌细胞株高效吸收，并在6小时内与溶酶体标记物LAMP-1共定位，而外部标记在赖氨酸残基上的VLP被较低效率吸收，可能反映了表面差异电荷和与细胞表面结合的倾向。将染料和药物分子注入VLP的腔中表明，光敏剂（PS），Zn-EpPor和药物结晶紫，米托蒽醌（MTX）和阿霉素（DOX）通过非共价相互作用与载体稳定缔合。我们证实了PS-PhMV和DOX-PhMV颗粒分别对前列腺癌，卵巢癌和乳腺癌细胞系的细胞毒性。我们的结果表明，源自PhMV的VLP提供了一种新的平台技术，用于输送成像剂和药物，并优先吸收到癌细胞中。因此，这些颗粒可被开发为用于癌症诊断和治疗的多功能工具。