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A series of novel benzimidazole-2-subsituted phenyl or pyridine propyl ketene derivatives were designed and synthesized. The biological activities of these derivatives were then evaluated as potential antitumour agents. These compounds were assayed for growth-inhibitory activity against HCT116, MCF-7 and HepG2 cell lines in vitro. The IC 50 values of compounds A 1 and A 7 against the cancer cells were 0.06–3.64 μM and 0.04–9.80 μM, respectively. Their antiproliferative activities were significantly better than that of 5-Fluorouracil (IC 50 : 56.96–174.50 μM) and were close to that of Paclitaxel (IC 50 : 0.026–1.53 μM). The activity of these derivatives was over 100 times more effective than other reported structures of chalcone analogues (licochalcone A). A preliminary mechanistic study suggested that these compounds inhibit p53-MDM2 binding. Compounds A 1 , A 7 and A 9 effectively inhibited tumour growth in BALB/c mice with colon carcinoma HCT116 cells. The group administered 200 mg/kg of compound A 7 showed a 74.6% tumour growth inhibition with no signs of toxicity at high doses that was similar to the inhibition achieved with the 12.5 mg/kg irinotecan positive control (70.2%). Therefore, this class of benzimidazole-2-subsituted phenyl or pyridine propyl ketene derivatives represents a promising lead structure for the development of possible p53-MDM2 inhibitors as new antitumour agents. [ABSTRACT FROM AUTHOR]

Abstract: A novel class of small-molecule inhibitors of MDM2–p53 interaction with a (E)-3-benzylideneindolin-2-one scaffold was identified using an integrated virtual screening strategy that combined both pharmacophore- and structure-based approaches. The hit optimisation identified several compounds with more potent activity than the hit compound and the positive drug nutlin-3a, especially compound 1b, which exhibited both the highest binding affinity to MDM2 (K i = 0.093 μM) and the most potent antiproliferative activity against HCT116 (wild type p53) cells (GI50 = 13.42 μM). Additionally, 1b dose-dependently inhibited tumour growth in BALB/c mice bearing CT26 colon carcinoma, with no visible sign of toxicity. In summary, compound 1b represents a novel and promising lead structure for the development of anticancer drugs as MDM2–p53 interaction disruptors. [Copyright &y& Elsevier]