A novel adamantane thiadiazole derivative induces mitochondria-mediated apoptosis in lung carcinoma cell line. Issue 1 (1st January 2017) - Ali, Ayat G.
Graphical abstract: Four new adamantane thiadiazole derivatives were designed and theoretically tested for their binding affinities to a model of an apoptosis inhibitor protein using molecular modeling. The adamantane thiadiazole derivative interacted with the highest binding affinity was synthesized, characterized and screened for its in vitro cytotoxic activity against different cancer cell lines as well as normal cell line using 5-fluorouracil as a standard positive control. Lung carcinoma cell line was chosen to further study if the mechanism of cytotoxic activity was through the induction of apoptosis. Inducing apoptosis in lung carcinoma cell line was assessed by various biochemical and morphological characteristics. Biochemically: The effect of the selected adamantane thiadiazole derivative on cell cycle and its ability to induce apoptosis were checked through flow cytometry. Caspase-3 activity was detected by a colorimetric method. Real time-polymerase chain reaction was used to detect p53, caspase-3, bcl-2 and bax gene expression. Morphologically: Changes in cell surface morphology, granulation and average surface roughness were detected using atomic force microscopy. Cell shrinkage, increase in cytoplasmic organelles, changes in mitochondrial number and morphology, chromatin condensation, membrane blebbing and formation of apoptotic bodies were detected using transmission electron microscopy. The obtained results suggest that the selected adamantane thiadiazole derivative exerted its antitumor activity against lung carcinoma cell line through the induction of the intrinsic (mitochondrial) apoptotic pathway. Highlights: A novel adamantane thiadiazole derivative, ATD-4, was synthesized and characterized. The ability of ATD-4 to induce apoptosis in lung carcinoma cell line was studied. ATD-4 induced mitochondria-mediated apoptosis in lung carcinoma cell line. Abstract: The interaction of organic compounds with apoptosis regulatory proteins is an attractive field of research because of its relevance in the development of new chemotherapeutic agents for cancer treatment. Our group designed four new adamantane thiadiazole derivatives (ATDs). The four ATDs were theoretically tested for their binding affinities to a model of an apoptosis inhibitor protein using molecular modeling. ATD-4 which interacted with the highest binding affinity was synthesized and characterized. The in vitro cytotoxicity of ATD-4 against different cancer cell lines as well as normal cell line was determined and compared with 5-fluorouracil as a standard positive control. The lung carcinoma cell line that showed the highest cytotoxic activity due to ATD-4 treatment was chosen to further study if ATD-4 can perform its cytotoxic activity through the induction of apoptosis as expected from molecular modeling. Inducing apoptosis by ATD-4 in lung carcinoma cell line was assessed by various biochemical and morphological characteristics. Biochemically: The effect of ATD-4 on cell cycle and its ability to induce apoptosis were checked through flow cytometry. Caspase-3 activity was detected by a colorimetric method. Real time-polymerase chain reaction (q-PCR) was used to detect p53, caspase-3, bcl-2 and bax gene expression. Morphologically: Changes in cell surface morphology, granulation and average surface roughness were detected using atomic force microscopy (AFM). Cell shrinkage, increase in cytoplasmic organelles, changes in mitochondrial number and morphology, chromatin condensation, membrane blebbing and formation of apoptotic bodies were detected using transmission electron microscopy (TEM). The obtained results suggest that ATD-4 exerted its antitumor activity against A549 cells through the induction of the intrinsic (mitochondrial) apoptotic pathway.