Wilson James N, Liu Wenjun, Brown Adrienne S, Landgraf Ralf
Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33124, USA.
Org Biomol Chem. 2015 May 7;13(17):5006-11. doi: 10.1039/c5ob00239g.
We report the photophysical properties, binding-induced turn-on emission, and fluorescence imaging of the cellular uptake and distribution of lapatinib, an EGFR/ERBB inhibitor. Lapatinib, a type II, i.e. inactive state, inhibitor that targets the ATP binding pocket of the EGFR family of receptor tyrosine kinases. DFT calculations predict that the 6-furanylquinazoline core of lapatinib should exhibit an excited state with charge transfer character and an S0 to S1 transition energy of 3.4 eV. Absorption confirms an optical transition in the near UV to violet, while fluorescence spectroscopy shows that photoemission is highly sensitive to solvent polarity. The hydrophobicity of lapatinib leads to fluorescent aggregates in solution, however, binding to the lipid-carrier protein, BSA or to the kinase domain of ERBB2, produces spectroscopically distinct photoemission. Confocal fluorescence microscopy imaging of lapatinib uptake in ERBB2-overexpressing MCF7 and BT474 cells reveals pools of intracellular inhibitor with emission profiles consistent with aggregated lapatinib.
我们报告了表皮生长因子受体（EGFR）/人表皮生长因子受体2（ERBB）抑制剂拉帕替尼的光物理性质、结合诱导的开启发射以及细胞摄取和分布的荧光成像。拉帕替尼是一种II型抑制剂，即非活性状态抑制剂，靶向受体酪氨酸激酶EGFR家族的ATP结合口袋。密度泛函理论（DFT）计算预测，拉帕替尼的6-呋喃基喹唑啉核心应表现出具有电荷转移特征的激发态，且从基态（S0）到第一激发单重态（S1）的跃迁能量为3.4电子伏特。吸收光谱证实了在近紫外到紫光区域的光学跃迁，而荧光光谱表明光发射对溶剂极性高度敏感。拉帕替尼的疏水性导致其在溶液中形成荧光聚集体，然而，与脂质载体蛋白牛血清白蛋白（BSA）或ERBB2的激酶结构域结合后，会产生光谱上不同的光发射。对过表达ERBB2的MCF7和BT474细胞摄取拉帕替尼的共聚焦荧光显微镜成像显示，细胞内抑制剂池的发射谱与聚集的拉帕替尼一致。
