Molatlhegi, Refilwe P.Phulukdaree, AlisaAnand, KrishnanGengan, Robert M.Tiloke, CharletteChuturgoon, A.A.2015-08-272015-08-272015-07-02Molatlhegi RP, Phulukdaree A, Anand K, Gengan RM, Tiloke C, Chuturgoon AA (2015) Cytotoxic Effect of a Novel Synthesized Carbazole Compound on A549 Lung Cancer Cell Line. PLoS ONE 10(7): e0129874. DOI:10.1371/journal.pone.0129874.1932-620310.1371/journal.pone.0129874http://hdl.handle.net/2263/49605S1 Fig. MTT assay measured in untreated (control) and 1% DMSO (vehicle control) treated A549 cells. The data showed no significant cytotoxicity.S2 Fig.Western blots showing the effect of ECAP on the expression of Bax, Bcl-2, p53, Nrf2, Hsp70 and SOD. The original western blots which were used for western blot analysis (Fig 6).Increased death rates due to lung cancer have necessitated the search for potential novel anticancer compounds such as carbazole derivatives. Carbazoles are aromatic heterocyclic compounds with anticancer, antibacterial and anti-inflammatory activity. The study investigated the ability of the novel carbazole compound (Z)-4-[9-ethyl-9aH-carbazol-3-yl) amino] pent-3-en-2-one (ECAP) to induce cytotoxicity of lung cancer cells and its mechanism of action. ECAP was synthesized as a yellow powder with melting point of 240-247 °C. The 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), lipid peroxidation and comet assays were used to assess the cytotoxic effect of the compound on A549 lung cancer cells. Protein expression was determined using western blots, apoptosis was measured by luminometry (caspase-3/7, -8 and -9) assay and flow cytometry was used to measure phosphatidylserine (PS) externalisation. ECAP induced a p53 mediated apoptosis of lung cancer cells due to a significant reduction in the expression of antioxidant defence proteins (Nrf2 and SOD), Hsp70 (p < 0.02) and Bcl-2 (p < 0.0006), thereby up-regulating reactive oxygen species (ROS) production. This resulted in DNA damage (p < 0.0001), upregulation of Bax expression and caspase activity and induction of apoptosis in lung cancer cells. The results show the anticancer potential of ECAP on lung cancer.en© 2015 Molatlhegi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License.Lung cancerCarbazolesYellow powderProteinArticle