In Vitro Evaluation of the Multidrug Resistance Reversing Activity of Novel Imidazo[4,5-b]pyridine Derivatives.

BACKGROUND/AIM: Malignant diseases present a significant public health burden worldwide and their treatment is further complicated by the phenomenon of multidrug resistance. Derivatives of imidazopyridine exhibit several remarkable pharmacological activities and they could reverse the multidrug resistance of cancer cells due to overexpressing P-glycoprotein. MATERIALS AND METHODS: A series of novel imidazo[4,5-b]pyridine derivatives were synthesized and their biological activities were evaluated in vitro using parental (PAR) and multidrug resistant (MDR; ABCB1-overexpressing) mouse T-lymphoma cells. The cytotoxic activity and selectivity of the tested compounds were assessed by the thiazolyl blue tetrazolium bromide (MTT) assay, the ABCB1 modulating activity was measured by rhodamine 123 accumulation assay using flow cytometry. RESULTS: Six compounds (b, c, d, f, h and i) showed moderate-to-high cytotoxic activity on the tested cell lines, while derivative i presented with promising selectivity towards the MDR cell line. Derivatives a, d, f, g and i were proven to be effective modulators of the ABCB1 multidrug efflux pump, with two compounds showing efflux pump modulatory activity at 2 µM concentration. CONCLUSION: Based on our experimental results, compounds that showed potent activity are those with a short carbon side chain; a methoxy group on the benzene ring; a heterocyclic (triazole) side chain and the presence of an alkylated N-atom at position 4.

1-Do-decyl-indoline-2,3-dione.

The structure of the title compound, C20H29NO2, is isotypic to that of its homologue 1-octylindoline-2,3-dione. The indoline ring and the two carbonyl-group O atoms are approximately coplanar, the largest deviation from the mean plane being 0.0760 (10) Å. The mean plane through the fused-ring system is nearly perpendicular to the mean plane passing through the 1-dodecyl chain [dihedral angle = 77.69 (5)°]. All C atoms of the dodecyl group are in an anti-periplanar arrangement. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming a three-dimensional network.

1-(Prop-2-yn-yl)indoline-2,3-dione.

The structure of the title compound, C11H7NO2, is isotypic to that of its homologue, 1-octylindoline-2,3-dione [Qachchachi et al. (2013 ▶). Acta Cryst. E69, o1801]. The indoline ring and the two carbonyl O atoms are approximately coplanar, the largest deviation from the mean plane being 0.021 (1) Šfor one of the O atoms. The mean plane through the fused ring system is nearly perpendicular to the propynyl group, as indicated by the N-C-C-C torsion angle of 77.9 (1)°. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds and π-π inter-actions between benzene rings [inter-centroid distance = 3.5630 (10) Å], forming a three-dimensional structure.

Benzo[b]-1,8-naphthyridine derivatives: synthesis and reversal activity on multidrug resistance.

A series of benzo[b]-1,8-naphthyridine derivatives branched with various side-chains and substituents were prepared with the aim of being investigated as multidrug resistance (MDR) modulators. The syntheses were achieved from 2-halonicotinic acid and suitable aryl-amines according to a three-step procedure. All the derivatives were tested in vitro on mouse T-Lymphoma cell line L5178 transfected by MDR1 gene and the chemosensitizing properties of the compounds were compared to those of verapamil and propranolol, as well as to several other tricyclic derivatives like phenothiazines and acridines. Most of the compounds tested reversed the MDR of tumour cells more effectively than the reference drugs did and they showed more potent chemosensitizing activity than phenothiazine and acridine derivatives have.