Recent studies in colorectal cancer patients (CRC) have shown that increased resistance to thymidylate synthase (TS) inhibitors such as 5-fluorouracil (5-FU), reduce the efficacy of standard of care (SoC) treatment regimens. The nucleotide pool cleanser dUTPase is highly expressed in CRC and is an attractive target for potentiating anticancer activity of chemotherapy. The purpose of the current work was to investigate the activity of P, P-di(2′,5′-dideoxy-5′-selenouridinyl)-tetraphosphate (P-SedU), a selenium-modified symmetrically capped dinucleoside with prodrug capabilities that is specifically activated by dUTPase. Using mechanochemistry, P-SedU and the corresponding selenothymidine analogue P-SeT were prepared with a yield of 19% and 30% respectively. The phosphate functionality facilitated complexation with the amphipathic cell-penetrating peptide RALA to produce nanoparticles (NPs). These NPs were designed to deliver P-SedU intracellularly and thereby maximise activity. The NPs demonstrated effective anti-cancer activity and selectivity in the HCT116 CRC cell line, a cell line that overexpresses dUTPase; compared to HT29 CRC cells and NCTC-929 fibroblast cells which have reduced levels of dUTPase expression. studies in BALB/c SCID mice revealed no significant toxicity with respect to weight or organ histology. Pharmacokinetic analysis of blood serum showed that RALA facilitates effective delivery and rapid internalisation into surrounding tissues with NPs eliciting lower plasma C than the equivalent injection of free P-SedU, translating the findings. Tumour growth delay studies have demonstrated significant inhibition of growth dynamics with the tumour doubling time extended by >2weeks. These studies demonstrate the functionality and action of a new pro-drug nucleotide for CRC.

中文翻译：

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与肽一起配制的基于核苷酸的前药的合成和表征，用于结直肠癌的纳米化疗

最近对结直肠癌患者 (CRC) 的研究表明，对胸苷酸合成酶 (TS) 抑制剂（例如 5-氟尿嘧啶 (5-FU)）的耐药性增加，会降低标准护理 (SoC) 治疗方案的疗效。核苷酸池清洁剂 dUTPase 在 CRC 中高表达，是增强化疗抗癌活性的有吸引力的靶标。当前工作的目的是研究 P, P-二(2',5'-二脱氧-5'-硒尿苷基)-四磷酸 (P-SedU) 的活性，P-SedU 是一种硒修饰的对称加帽二核苷，具有前药功能，被 dUTPase 特异性激活。利用机械化学方法，制备了 P-SedU 和相应的硒代胸苷类似物 P-SeT，产率分别为 19% 和 30%。磷酸盐功能促进了与两亲性细胞穿透肽 RALA 的络合，生成纳米颗粒 (NP)。这些 NP 旨在在细胞内传递 P-SedU，从而最大限度地提高活性。 NPs 在 HCT116 CRC 细胞系（一种过度表达 dUTPase 的细胞系）中表现出有效的抗癌活性和选择性；与 HT29 CRC 细胞和 NCTC-929 成纤维细胞相比，dUTPase 表达水平降低。对 BALB/c SCID 小鼠的研究表明，在体重或器官组织学方面没有显着毒性。血清药代动力学分析表明，与同等注射的游离 P-SedU 相比，RALA 有助于有效递送并快速内化到周围组织中，NP 引起的血浆 Cmax 更低，这转化了这一发现。肿瘤生长延迟研究表明，生长动态受到显着抑制，肿瘤倍增时间延长超过 2 周。这些研究证明了一种新的 CRC 前药核苷酸的功能和作用。