Wu Xuelei, Yuan Siming, Wang Erqiong, Tong Yang, Ma Guolin, Wei Kaiju, Liu Yangzhong
CAS Key Laboratory of Soft Matter Chemistry, CAS High Magnetic Field Laboratory, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
Metallomics. 2017 May 24;9(5):546-555. doi: 10.1039/c6mt00303f.
In spite of their wide application, the cellular uptake of platinum based anticancer drugs is still unclear. The copper transport protein, hCTR1, is proposed to facilitate the cellular uptake of cisplatin, whereas organic cation transport (OCT) is more important for oxaliplatin. It has been reported that both N-terminal and C-terminal metal binding motifs of hCTR1 are highly reactive to cisplatin, which is the initial step of protein assisted cellular uptake of cisplatin. It is still unknown how the platinum drugs in hCTR1 transfer to cytoplasmic media, and whether various platinum complexes possess different activities in this process. Herein, we investigated the reaction of the platinated C-terminal metal binding motif of hCTR1 (C8) with the down-stream protein Atox1. Results show that Atox1 is highly reactive to the platinated C8 adducts of cisplatin and transplatin, whereas the oxaliplatin/C8 adduct is much less reactive. The platinum transfer from C8 to Atox1 occurs in the reaction, which results in the protein unfolding of Atox1. These results demonstrated that the platinated intracellular-domain of hCTR1 is reactive to Atox1, and the reactivity is dependent on the ligand and the coordination structure of platinum complexes. The different reactivity is consistent with the hypothesis that hCTR1 is more significant in the transport of cisplatin than that of oxaliplatin.
尽管铂类抗癌药物应用广泛，但其细胞摄取机制仍不清楚。据推测，铜转运蛋白hCTR1有助于顺铂的细胞摄取，而有机阳离子转运（OCT）对奥沙利铂更为重要。据报道，hCTR1的N端和C端金属结合基序对顺铂都具有高度反应性，这是蛋白质辅助顺铂细胞摄取的初始步骤。hCTR1中的铂类药物如何转移到细胞质介质中，以及各种铂配合物在此过程中是否具有不同的活性仍不清楚。在此，我们研究了hCTR1的铂化C端金属结合基序（C8）与下游蛋白Atox1的反应。结果表明，Atox1对顺铂和反铂的铂化C8加合物具有高度反应性，而奥沙利铂/C8加合物的反应性则低得多。反应中发生了铂从C8转移到Atox1的过程，这导致Atox1的蛋白质解折叠。这些结果表明，hCTR1的铂化细胞内结构域对Atox1具有反应性，且反应性取决于铂配合物的配体和配位结构。不同的反应性与hCTR1在顺铂转运中比在奥沙利铂转运中更重要的假设一致。
