Abstract：
For the improved delivery of cancer therapeutics and imaging agents, the conjugation of cell-penetrating peptides (CPPs) increases the cellular uptake and water solubility of agents. Among the various CPPs, arginine-rich peptides have been the most widely used. Combining CPPs with enzyme-responsive peptides presents an innovative strategy to target specific intracellular enzymes in cancer cells and when combined with the appropriate click chemistry can enhance theranostic drug delivery through the formation of intracellular self-assembled nanostructures. However, one drawback of CPPs is their high positive charge which can cause nonspecific binding, leading to off-target accumulation and potential toxicity. Hence, balancing cell-specific penetration, toxicity, and biocompatibility is essential for future clinical efficacy. We synthesized six cancer-specific, legumain-responsive RnAANCK peptides containing one to six arginine residues, with legumain being an asparaginyl endopeptidase that is overexpressed in aggressive prostate tumors. When conjugated to Alexa Fluor 488, R1-R6AANCK peptides exhibited a concentration- and time-dependent cell penetration in prostate cancer cells, which was higher for peptides with higher R values, reaching a plateau after approximately 120 min. Highly aggressive DU145 prostate tumor cells, but not less aggressive LNCaP cells, self-assembled nanoparticles in the cytosol after the cleavage of the legumain-specific peptide. The in vivo biocompatibility was assessed in mice after the intravenous injection of R1-R6AANCK peptides, with concentrations ranging from 0.0125 to 0.4 mmol/kg. The higher arginine content in R4-6 peptides showed blood and urine indicators for the impairment of bone marrow, liver, and kidney function in a dose-dependent manner, with instant hemolysis and morbidity in extreme cases. These findings underscore the importance of designing peptides with the optimal arginine residue length for a proper balance of cell-specific penetration, toxicity, and in vivo biocompatibility.
摘要：
为了改善癌症治疗剂和显像剂的递送，细胞穿透肽(CPPs)的结合增加了细胞摄取和药剂的水溶性。在各种CPP中，富含精氨酸的肽已被最广泛地使用。将CPP与酶响应性肽组合提出了一种创新策略，以靶向癌细胞中的特定胞内酶，并且当与适当的点击化学组合时，可以通过形成细胞内自组装纳米结构来增强治疗药物递送。然而,CPPs的一个缺点是它们的高正电荷可以引起非特异性结合，导致脱靶积累和潜在毒性。因此，平衡特定电池的渗透，毒性,生物相容性对未来的临床疗效至关重要。我们合成了六种癌症特异性，legumain反应性RnAANCK肽含有1至6个精氨酸残基，legumain是一种天冬酰胺酰内肽酶，在侵袭性前列腺肿瘤中过表达。当与AlexaFluor488缀合时，R1-R6AANCK肽在前列腺癌细胞中表现出浓度和时间依赖性的细胞穿透，对于R值较高的肽，大约120分钟后达到平稳状态。高侵袭性DU145前列腺肿瘤细胞，但没有那么积极的LNCaP细胞，豆科蛋白特异性肽裂解后，胞质溶胶中的自组装纳米颗粒。静脉注射R1-R6AANCK肽后，在小鼠中评估体内生物相容性，浓度范围为0.0125至0.4mmol/kg。R4-6肽中精氨酸含量较高显示血液和尿液指标对骨髓的损害，肝脏,和肾功能呈剂量依赖性,在极端情况下具有即时溶血和发病率。这些发现强调了设计具有最佳精氨酸残基长度的肽对于细胞特异性渗透的适当平衡的重要性。毒性,和体内生物相容性。
