Faculty of Pharmacy, Keio University, Tokyo, Japan.
Faculty of Pharmacy, Keio University, Tokyo, Japan.
J Pharm Sci. 2022 Aug;111(8):2201-2209. doi: 10.1016/j.xphs.2022.04.020. Epub 2022 May 6.
Methoxy trityl groups are acid-responsive protecting groups that are routinely used in the process of nucleoside analog synthesis. This study investigated the potential of methoxy trityl groups, monomethoxy trityl (MMT), dimethoxy trityl (DMT), and trimethoxy trityl (TMT), as acid-responsive substituents for designing anti-cancer cytidine analog prodrugs. For this purpose, we synthesized six gemcitabine (GEM) derivatives, which were modified either 4-(N)- or 5'-(O)-sites with MMT, DMT, and TMT, as candidates for anti-cancer cytidine analog prodrugs. In vitro dissociation test of methoxy trityl groups clearly showed that the acid responsivity of the methoxy trityl moieties was in the order TMT>DMT>MMT. Furthermore, the rate of 5'-(O)-methoxy tritylation was higher than that of 4-(N)-methoxy tritylation. Along with high acid-responsivity, trimethoxy trityl-O-GEM (TMT-O-GEM) showed superior cytotoxicity against 2D cultured human breast cancer cells (MCF-7 and MDA-MB-231) and human pancreatic cancer cells (AsPC-1) compared to other methoxy-tritylated GEM derivatives. Moreover, TMT-O-GEM suppressed the growth of MCF-7 spheroids compared with trimethoxy trityl-N-GEM (TMT-N-GEM). Both TMT-O-GEM and TMT-N-GEM were negligibly deprotected and metabolized in mouse or human serum after 72 h, indicating that trimethoxy tritylation inhibits deamination by cytidine deaminase. These results indicate that 5'-(O)-trimethoxy tritylation is a potent approach for the development of anti-cancer cytidine analog prodrugs.
甲氧三苯甲基基团是一种酸响应保护基团，常用于核苷类似物合成过程。本研究探讨了甲氧三苯甲基基团（MMT）、二甲氧基三苯甲基（DMT）和三甲氧基三苯甲基（TMT）作为设计抗癌胞苷类似物前药的酸响应取代基的潜力。为此，我们合成了六种吉西他滨（GEM）衍生物，它们在 4-（N）-或 5'-（O）-位被 MMT、DMT 和 TMT 修饰，作为抗癌胞苷类似物前药的候选物。甲氧三苯甲基基团的体外解离试验清楚地表明，甲氧三苯甲基部分的酸响应性顺序为 TMT>DMT>MMT。此外，5'-（O）-甲氧三苯甲基化的速率高于 4-（N）-甲氧三苯甲基化的速率。与高酸响应性相结合，三甲氧基三苯甲基-O-吉西他滨（TMT-O-GEM）对 2D 培养的人乳腺癌细胞（MCF-7 和 MDA-MB-231）和人胰腺癌细胞（AsPC-1）的细胞毒性优于其他甲氧三苯甲基化的 GEM 衍生物。此外，与三甲氧基三苯甲基-N-吉西他滨（TMT-N-GEM）相比，TMT-O-GEM 抑制 MCF-7 球体的生长。在 72 小时后，TMT-O-GEM 和 TMT-N-GEM 在小鼠或人血清中几乎没有脱保护和代谢，表明三甲氧基三苯甲基化抑制胞苷脱氨酶的脱氨作用。这些结果表明，5'-（O）-三甲氧基三苯甲基化是开发抗癌胞苷类似物前药的一种有效方法。
