Elsevier

Pharmacological Reports

Volume 66, Issue 1, February 2014, Pages 100-106
Pharmacological Reports

Original research article
Biological approach of anticancer activity of new benzimidazole derivatives

https://doi.org/10.1016/j.pharep.2014.01.001Get rights and content

Abstract

Background

A series of new benzimidazole derivatives, earlier synthesized, was tested in vitro as new bioreductive prodrugs with the potential anticancer activity. Their effect on the DNA destruction and growth inhibition into selected tumor cell lines at normoxia and hypoxia conditions was determined.

Methods

The human lung adenocarcinoma A549 cell line was used to determine the anticancer activity of the analyzed compounds by using WST-1 assay. The apoptosis test (caspase 3/7 assay) was used to define the cytotoxic way of tumor cells death. Additionally test In situ DNA Damage Assay Kit was applied to recognize the DNA destruction.

Results

Four of the examined compounds (1, 3, 7, 9) show a very good antiproliferative effect and three of them are specific for hypoxia conditions (2, 4, 8).

Conclusion

Compound 8 is the most cytotoxic against human lung adenocarcinoma A549 cells at hypoxic conditions. Hypoxia/normoxia cytotoxic coefficient of compound 8 (4.75) is close to hypoxia/normoxia cytotoxic coefficient of tirapazamine (5.59) – reference substance in our experiments and this parameter locates it between mitomycin C and 2-nitroimidazole (misonidazole). The screening test of the caspase-dependent apoptosis proved that the exposure of compounds 12 and 78 against A549 cells for a 48 h promote apoptotic cell death. Additionally, the test of the DNA damage established that compounds 1, 2, 7, 8 are specific agents for the hypoxia-selective cytotoxicity of nitrobenzimidazoles [6], [26].

Introduction

Hypoxia is the leading targeting in cancer therapy. The poor oxygen concentration, which is characteristic for solid tumors affects many processes such as angiogenesis, erythropoiesis and alteration of cellular metabolism at tumor cells [5]. Hypoxia, for sure, can influence the survival of tumor cells by different changes in the gene expression that reduce apoptosis and increase autophagy, vasculogenesis, metastasis, immune reactivity and activity of receptor tyrosine kinase. Generally tumor cells under hypoxia lose genomic stability by generating the reactive oxygen species (ROS) and suppress regulation of DNA repair pathways [8], [10], [21], [23], [25].

In order to minimize those survival effects of tumor cells, scientists conduct research into targeted therapy with the use of specific substances which have a bioreductive mechanism of action at hypoxia conditions [1], [6], [13]. This concept of approaching new chemical classes of pro-drugs activated to selective cytotoxins, was started by using derivatives of aniline nitrogen mustard as the first class of bioreducive prodrugs. Now different chemical bonds such as nitro group, quinones, heterocyclic N-oxides (CB 1954, tirapazamina, AQ4N) are currently radical prodrugs useful for cancer therapy (Fig. 1) [11], [12], [14], [20]. The mechanisms of the metabolic activation of bioreductive prodrugs were shown at Scheme 1 [25]. The common feature of all these new chemical compounds is their ability to generate cytotoxic agents for DNA damage. A new group of benzimidazole derivatives, i.e. potential new agents of the DNA destruction, should be particularly paid attention to [2], [3], [4]. These compounds are intensively being worked on as they might have new anticancer properties [7], [16], [17], [22], [24]. It was the reason for initiating our experiments in the group of new benzimidazole derivatives and N-oxide benzimidazole derivatives. Therefore, we analyzed a series of benzimidazole derivatives (1–12) to elucidate their contribution to the antyproliferation activity at normoxia and hypoxia conditions. The particularly selective activity of N-oxide benzimidazole derivatives into hypoxia was very interesting for us. Additionally we determined their cytotoxic activity by necrosis or apoptosis. The main reason for our experiments concerned their effect of DNA damage at hypoxia and normoxia cancer cells.

Section snippets

Cell culture

A549 (human lung adenocarcinoma) cell line was purchased from Health Protection Agency Culture Collections (ECACC, Salisburg, UK), were cultured in F12K medium (HyClone, UK) supplemented with 10% heat-inactivated fetal bovine serum (FBS), penicillin (10,000 U/ml) and streptomycin (10,000 μg/ml) in 5% CO2 at 37 °C.

Hypoxic cells were created by culture of A549 cells in hypoxic incubator in 1% O2 and 5% CO2 at 37 °C for 24 h before treatment.

DNA damage assay

The effect of compounds on DNA damage was determined based on

Chemistry

The structure of the new benzimidazole derivatives and N-oxide benzimidazole derivatives is shown in Fig. 2. The cyclocondensation of diamine with aldehydes was prepared according to the known and described in literature method [9], [18], [19]. We worked out the conditions for obtaining new benzimidazole derivatives and N-oxide benzimidazole derivatives as we described earlier [26]. Structure of new benzimidazole derivatives was established by X-ray crystal structure analysis [6].

Biological activities

Human lung

Discussion

From our screening tests, we found that compounds 1 and 7 were the most effective in the inhibition of the cell growth in normoxic as well as in hypoxic A549 cells. But their cytotoxic activity at hypoxia drew attention too. The compounds 2 and 8 were more potent to specifically inhibit cell viability of hypoxic cancer cells while they were less effective in normoxic cells. Moreover, hypoxic/aerobic cytotoxicity coefficient of compound 8 was 4.75 while for tirapazamine was 5.59. This parameter

Funding

Synthetical and biochemical research is supported by Medical University of Łódź, Poland (503-3015-1, Grant No. 507-13-052).

References (26)

  • J.A. Forsythe et al.

    Activation of endothelial growth factor gene transcription by hypoxia-inducible factor 1

    Mol Cell Biol

    (1996)
  • D. Jerchel et al.

    Zur darstellung der benzimidazole

    Liebigs Annalen Chem

    (1952)
  • L.S. Kurtzberg et al.

    Genz-644282, a novel non-camptothecin topoisomerase I inhibitor for cancer treatment

    Clin Cancer Res

    (2011)
  • Cited by (28)

    • Deciphering the nature of binding of dexlansoprazole with DNA: Biophysical and docking approaches

      2022, International Journal of Biological Macromolecules
      Citation Excerpt :

      Various pharmacological characteristics of benzimidazoles and their derivatives include antiulcer, anthelmintic, antileishmanial, antiprotozoal, antimicrobial [4,5], anti-inflammatory, antiviral, anticancer, and analgesic [6] activities. Drugs with benzimidazole nucleus find use in several diseases like- Ridinilazole as antibacterial, Astemizole and Bilastine as antihistamines [6], Nocodazole, Veliperib and Pracinostat as antitumor agents [7], Esomeprazole, Bezitramide as an analgesic [8], Triclabendazole, Albendazole, Mebendazole and Flubendazole as antihelminthics [9], Enviradine, Samatasvir and Maribavir as antivirals, Candesartan and Mibefradil as antihypertensive [4,10,11] agents, Dexlansoprazole and Rabeprazole as proton pump inhibitors [8,12–14]. The various medicinal properties of benzimidazoles have attracted researchers in synthesizing their derivatives, focusing on their biological activities, as evident from the current literature [13–15].

    • An electrochemical study on the redox chemistry of cyclic benzimidazole derivatives with potent anticancer activity

      2019, Electrochimica Acta
      Citation Excerpt :

      The benzimidazole scaffold in numerous biologically active molecules is widely explored in the development of new anticancer agents. Various substituted derivatives of benzimidazole have been reported to show remarkable antitumor activity [3–6], in addition to numerous other biological properties (such as antimicrobial [7], antiviral [8], antihypertensive [9], anti-inflammatory [10], antioxidant activity [11,12], etc.). One important feature for their biological activities is the structural similarity of benzimidazole moiety with naturally occurring nucleotides, which enables easy interaction of these compounds with biological molecules like DNA, RNA or proteins in living systems, thus playing a crucial role in their function [13].

    • Synthesis, cytotoxic and antimicrobial activities of novel cobalt and zinc complexes of benzimidazole derivatives

      2017, Journal of Organometallic Chemistry
      Citation Excerpt :

      Liu et al. suggested that Zn(II) complexes containing bis-benzimidazole derivatives could be candidate for further evaluation as chemotherapeutic agent for human cancers [52]. It was found that one of the new benzimidazole derivative was the most cytotoxic against A549 cells at hypoxic conditions [53]. The cytotoxicity of compounds against human lung bronchial epithelium cells was also examined.

    View all citing articles on Scopus
    View full text