Background/Objective: At least 25% of colorectal cancer (CRC) patients develop liver metastases (CRLM), and chemotherapeutic regimens based on the fluoropyrimidine (FP) drug 5-fluorouracil (5-FU) provide a survival advantage, but long-term survival is uncommon. The primary molecular target of FP drugs is thymidylate synthase (TS). Methods: A TS/Top1 dual-targeting cytotoxic mechanism for CF10/LV was confirmed by TS ternary complex detection by Western blot and by immunofluorescence detection of Top1 cleavage complexes. CF10/LV activated the ATR/Chk1 pathway consistent with enhanced replication stress and induced apoptosis. In vivo studies showed CF10 and CF10/LV eradicated liver metastasis in a CRLM model without scarring or weight loss, displaying therapeutic advantages relative to legacy FPs. Results: We demonstrated that a nanoscale FP polymer, CF10, displayed greater potency than expected based on FP content in part through more direct conversion to the TS-inhibitory metabolite, FdUMP. In this study, we tested CF10 for potency advantages relative to 5-FU and trifluorothymidine (TFT, the FP component of TAS-102) and confirmed a general potency advantage for CF10 in CRC cell lines in the Broad Institute PRISM screen. We demonstrated that this potency advantage is retained in CRC cells cultured with human-like folate levels and is enhanced by LV co-treatment to a similar extent as that by 5-FU. Our results confirm CF10 development proceeding as a CF10/LV combination. Mechanistically, CF10 cytotoxicity closely correlates with poisons of DNA topoisomerase 1 (Top1) in the PRISM screen relative to 5-FU and TFT. Conclusions: Our pre-clinical data support an early-phase clinical trial for CF10 for treating liver-metastatic CRC.
背景/目的：至少25%的结直肠癌（CRC）患者会发生肝转移（CRLM），基于氟嘧啶（FP）药物5-氟尿嘧啶（5-FU）的化疗方案可带来生存获益，但长期生存并不常见。FP药物的主要分子靶点是胸苷酸合成酶（TS）。方法：通过Western blot检测TS三元复合物以及免疫荧光检测Top1切割复合物，证实了CF10/LV具有TS/Top1双靶点细胞毒性机制。CF10/LV激活了ATR/Chk1通路，这与增强的复制应激一致，并诱导了细胞凋亡。体内研究表明，在CRLM模型中，CF10和CF10/LV清除了肝转移灶，且未引起疤痕形成或体重减轻，相对于传统FP药物显示出治疗优势。结果：我们证明，一种纳米级FP聚合物CF10显示出比基于FP含量预期更高的效力，部分原因是其能更直接地转化为TS抑制性代谢物FdUMP。在本研究中，我们测试了CF10相对于5-FU和三氟胸苷（TFT，TAS-102的FP成分）的效力优势，并在Broad研究所的PRISM筛选中证实了CF10在CRC细胞系中具有普遍的效力优势。我们证明，在与人类相似叶酸水平下培养的CRC细胞中，这种效力优势得以保留，并且通过LV联合治疗得到增强，其增强程度与5-FU相似。我们的结果证实了CF10的开发是作为CF10/LV组合进行的。在机制上，相对于5-FU和TFT，在PRISM筛选中CF10的细胞毒性与DNA拓扑异构酶1（Top1）毒物密切相关。结论：我们的临床前数据支持开展针对CF10治疗肝转移性CRC的早期临床试验。
肿瘤(癌症)患者之家