New Polyether Macrocycles as Promising Antitumor Agents-Targeted Synthesis and Induction of Mitochondrial Apoptosis

Abstract

A series of previously unknown aromatic polyether macrodiolides containing a cis,cis-1,5-diene moiety in the molecule were synthesized in 47-74% yields. Macrocycle compounds were first obtained by intermolecular esterification of aromatic polyether diols with α,ω-alka-nZ,(n+4)Z-dienedioic acids mediated by N-(3-(dimethylamino)propyl)-N'-ethylcarbodiimide hydrochloride (EDC·HCl) and 4-(dimethylamino)pyridine (DMAP). For the synthesized compounds, studies of cytotoxicity on tumor (Jurkat, K562, U937), conditionally normal (HEK293) cell lines, and normal fibroblasts were carried out. CC50 was determined, and the therapeutic selectivity index of cytotoxic action (SI) in comparison with normal fibroblasts was evaluated. With the involvement of modern methods of flow cytometry for the most promising macrocycles, their effect on mitochondria and the cell cycle was investigated. It was found that a new macrocycle exhibits pronounced apoptosis-inducing activity toward Jurkat cells and can retard cell division by blocking at the G1/S checkpoint. Also, it was shown that the synthesized macrodiolides influence mitochondria due to their high ability to penetrate the mitochondrial membrane.

Scheme 1. Synthesis of α,ω-Alka-nZ,(n + 4)Z-dienedioic Acids 4a–c

Scheme 2. Synthesis of Aromatic Diols 5a–f

Scheme 3. Synthesis of Polyether Macrocycles 6–8

Figure 1

Detection of apoptosis caused by the change in the mitochondrial potential (ΔΨ) in Jurkat cells treated with compounds 6a, 6b, and 6c at concentrations of 1.5 CC50. The control sample contained untreated live cells; overall histogram of the phases of apoptosis with allowance for the cells with damaged mitochondria. The cells treated with staurosporine at a concentration of 0.2 μM served as the positive control. The cells were stained with MitoSense Red, annexin V-CF488A, and 7-AAD. The incubation time was 4 h. Detection of ROS ion production under the influence of the studied compounds in Yurkat culture cells. The incubation time was 4 h. Cell cycle phases for Jurkat cells treated with compounds 6a, 6b, and 6c at CC50 concentration. The incubation time of compounds with the cells was 24 h.