Conjugation of a Ru(II) Arene Complex to Neomycin or to Guanidinoneomycin Leads to Compounds with Differential Cytotoxicities and Accumulation between Cancer and Normal Cells

详细信息    查看全文

• 作者：Ariadna Grau-Campistany ; Anna Massaguer ; Dolors Carrion-Salip ; Flavia Barrag谩n ; Gerard Artigas ; Paula L贸pez-Sen铆n ; Virtudes Moreno ; Vicente March谩n
• 刊名：Molecular Pharmaceutics
• 出版年：2013
• 出版时间：May 6, 2013
• 年：2013
• 卷：10
• 期：5
• 页码：1964-1976
• 全文大小：452K
• 年卷期：v.10,no.5(May 6, 2013)
• ISSN：1543-8392

文摘

A straightforward methodology for the synthesis of conjugates between a cytotoxic organometallic ruthenium(II) complex and amino- and guanidinoglycosides, as potential RNA-targeted anticancer compounds, is described. Under microwave irradiation, the imidazole ligand incorporated on the aminoglycoside moiety (neamine or neomycin) was found to replace one triphenylphosphine ligand from the ruthenium precursor [(畏⁶-p-cym)RuCl(PPh₃)₂]⁺, allowing the assembly of the target conjugates. The guanidinylated analogue was easily prepared from the neomycin-ruthenium conjugate by reaction with N,N鈥?di-Boc-N鈥?triflylguanidine, a powerful guanidinylating reagent that was compatible with the integrity of the metal complex. All conjugates were purified by semipreparative high-performance liquid chromatography (HPLC) and characterized by electrospray ionization (ESI) and matrix-assisted laser desorption鈥搃onization time-of-flight (MALDI-TOF) mass spectrometry (MS) and NMR spectroscopy. The cytotoxicity of the compounds was tested in MCF-7 (breast) and DU-145 (prostate) human cancer cells, as well as in the normal HEK293 (Human Embryonic Kidney) cell line, revealing a dependence on the nature of the glycoside moiety and the type of cell (cancer or healthy). Indeed, the neomycin鈥搑uthenium conjugate (2) displayed moderate antiproliferative activity in both cancer cell lines (IC₅₀ 鈮?80 渭M), whereas the neamine conjugate (4) was inactive (IC₅₀ 鈮?200 渭M). However, the guanidinylated analogue of the neomycin鈥搑uthenium conjugate (3) required much lower concentrations than the parent conjugate for equal effect (IC₅₀ = 7.17 渭M in DU-145 and IC₅₀ = 11.33 渭M in MCF-7). Although the same ranking in antiproliferative activity was found in the nontumorigenic cell line (3 2 > 4), IC₅₀ values indicate that aminoglycoside-containing conjugates are about 2-fold more cytotoxic in normal cells (e.g., IC₅₀ = 49.4 渭M for 2) than in cancer cells, whereas an opposite tendency was found with the guanidinylated conjugate, since its cytotoxicity in the normal cell line (IC₅₀ = 12.75 渭M for 3) was similar or even lower than that found in MCF-7 and DU-145 cancer cell lines, respectively. Cell uptake studies performed by ICP-MS with conjugates 2 and 3 revealed that guanidinylation of the neomycin moiety had a positive effect on accumulation (about 3-fold higher in DU-145 and 4-fold higher in HEK293), which correlates well with the higher antiproliferative activity of 3. Interestingly, despite the slightly higher accumulation in the normal cell than in the cancer cell line (about 1.4-fold), guanidinoneomycin鈥搑uthenium conjugate (3) was more cytotoxic to cancer cells (about 1.8-fold), whereas the opposite tendency applied for neomycin鈥搑uthenium conjugate (2). Such differences in cytotoxic activity and cellular accumulation between cancer and normal cells open the way to the creation of more selective, less toxic anticancer metallodrugs by conjugating cytotoxic metal-based complexes such as ruthenium(II) arene derivatives to guanidinoglycosides.

Keywords:

ruthenium; cytotoxicity; cellular accumulation; RNA ligands; neomycin; guanidinoneomycin