Development of Novel Bis(indolyl)-hydrazide–Hydrazone Derivatives as Potent Microtubule-Targeting Cytotoxic Agents against A549 Lung Cancer Cells

Abstract

The biological significance of microtubules makes them a validated target of cancer therapy. In this study, we have utilized indole, an important pharmacological scaffold, to synthesize novel bis(indolyl)-hydrazide-hydrazone derivatives (NMK-BH compounds) and recognized NMK-BH3 as the most effective one in inhibiting A549 cell proliferation and assembly of tissue-purified tubulin. Cell viability experiments showed that NMK-BH3 inhibited proliferation of human lung adenocarcinoma (A549) cells, normal human lung fibroblasts (WI38) and peripheral blood mononuclear cells (PBMC) with IC50 values of ∼2, 48.5, and 62 μM, respectively. Thus, the relatively high cytotoxicity of NMK-BH3 toward lung carcinoma (A549) cells over normal lung fibroblasts (WI38) and PBMC confers a therapeutic advantage of reduced host toxicity. Flow cytometry, Western blot, and immunofluorescence studies in the A549 cell line revealed that NMK-BH3 induced G2/M arrest, mitochondrial depolarization, and apoptosis by depolymerizing the cellular interphase and spindle microtubules. Consistent with these observations, study in cell free system revealed that NMK-BH3 inhibited the microtubule assembly with an IC50 value of ∼7.5 μM. The tubulin-ligand interaction study using fluorescence spectroscopy indicated that NMK-BH3 exhibited strong and specific tubulin binding with a dissociation constant of ∼1.4 μM at a single site, very close to colchicine site, on β-tubulin. Collectively, these findings explore the cytotoxic potential of NMK-BH3 by targeting the microtubules and inspire its development as a potential candidate for lung cancer chemotherapy.

Synthesis and Biological Evaluation of Indole‐2‐carbohydrazide Derivatives as Anticancer Agents with Anti‐angiogenic and Antiproliferative Activities

“…Recently, indole derivatives bearing a carbohydrazide moiety have been found to exhibit potent anticancer, antibacterial, anti‐inflammatory, and antitubercular effects. Moreover, further studies of biological mechanisms have demonstrated that these derivatives can be targeted to inhibit signal proteins, such as β‐glucuronidase, Akt1, CYP1AY, and microtubules …”

“…Moreover,f urthers tudies of biological mechanisms have demonstrated that these derivatives can be targeted to inhibit signal proteins, such as b-glucuronidase, [30] Akt1, [31] CYP1AY, [32] and microtubules. [33] We have succeeded in using as tructure-based approach to discover ac lass of quinazolined erivatives that inhibitt he VEGFR-2 protein. [34] In this study,w ea ttempted to develop indole-2-carbohydrazide derivativesa sa nti-angiogenesis agents.…”

Role of Indole Scaffolds as Pharmacophores in the Development of Anti-Lung Cancer Agents

“…The mechanism of action of NMK-BH3 in NSCLC (A549 cells) revealed the disruption of the mitotic spindle and depolymerization of the interphase microtubule network ultimately led to apoptotic cell death. This is signified by the overexpression of Bax, p53, caspase 3, and caspase 9 and decrease in the Bcl-2 expression [80]. Their experiments revealed that NMK-BH3 was more sensitive to human lung adenocarcinoma A549 cells with IC 50 of~2 µM, while highly resistant to normal human lung fibroblasts (WI38) with IC 50 of 48.5 µM (24 fold).…”

“…The synthesis of NMK-BH3 was achieved as shown in Scheme 7 [80]. A solution of indole-2carboxylic acid (42)…”

Design, synthesis and in vitro cytotoxicity studies of novel β -carbolinium bromides

“…21–23 Inspired by the fascinating anticancer properties of β- carbolines and azolium salts, in this paper we designed a diverse series of β- carbolinium salts by incorporating remarkable features of β- carboline and 1-aryl-2-bromoethanones in single molecule as depicted in Fig. 2.…”