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- ItemCrucial Role of Reactive Oxygen Species (ROS) for the Proapoptotic Effects of Indirubin Derivatives in Cutaneous SCC Cells(Basel : MDPI, 2021) Zhu, Jiaqi; Langer, Peter; Ulrich, Claas; Eberle, JürgenEfficient drugs are needed for countering the worldwide high incidence of cutaneous squamous cell carcinoma (cSCC) and actinic keratosis. Indirubin derivatives represent promising candidates, but their effects in cSCC cells have not been reported before. Here, we investigated the efficacy of three indirubin derivatives (DKP-071,-073 and-184) in four cSCC cell lines. High efficacy was seen in SCL-I, SCL-II, SCC-12 and SCC-13, resulting in up to 80% loss of cell proliferation, 60% loss of cell viability and 30% induced apoptosis (10 µM). Apoptosis was further enhanced in com-binations with TNF-related apoptosis-inducing ligand (TRAIL). Induction of reactive oxygen species (ROS) appeared as critical for these effects. Thus, antioxidative pretreatment completely abol-ished apoptosis as well as restored cell proliferation and viability. Concerning the pathways, com-plete activation of caspases cascades (caspases-3,-4,-6,-7,-8 and-9), loss of mitochondrial membrane potential, activation of proapoptotic PKCδ (protein kinase C delta), inhibition of STAT3 (sig-nal transducer and activator of transcription 3), downregulation of antiapoptotic XIAP (X-linked inhibitor of apoptosis protein) and survivin as well as upregulation of the proapoptotic Bcl-2 protein Puma and the cell cycle inhibitor p21 were obtained. Importantly, all activation steps were pre-vented by antioxidants, thus proving ROS as a master regulator of indirubins’ antitumor effects. ROS induction presently develops as an important issue in anticancer therapy. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
- ItemOne Pot Synthesis and Characterization of Mono and Di-Substituted Azo-Containing Amides(Shibabad : Chemic Publ. Co., 2015) Khera, Rasheed Ahmad; Iqbal, Munawar; Tahir, M. Asif; Hanif, M. Asif; Langer, PeterAzo-containing amides and their derivatives were synthesized by the reaction of 4-(phenyldiazenyl)aniline with different substituted benzoyl chlorides. The characterization of these synthesized compounds were based on their IR, 1H NMR spectra and elemental analysis with excellent yields.
- Item2,4-Bis(arylethynyl)-9-chloro-5,6,7,8-tetrahydroacridines: synthesis and photophysical properties(Frankfurt, M. : Beilstein-Institut zur Förderung der Chemischen Wissenschaften, 2021) Tka, Najeh; Ayed, Mohamed Adnene Hadj; Braiek, Mourad Ben; Jabli, Mahjoub; Chaaben, Noureddine; Alimi, Kamel; Jopp, Stefan; Langer, PeterAcridine derivatives have attracted considerable interest in numerous areas owing to their attractive physical and chemical properties. Herein, starting from readily available anthranilic acid, an efficient synthesis of 2,4-bis(arylethynyl)-9-chloro-5,6,7,8-tetrahydroacridine derivatives was accomplished via a one-pot double Sonogashira cross-coupling method. The UV-visible absorption and emission properties of the synthesized molecules have been examined. Additionally, theoretical studies based on density functional theory (DFT/B3LYP/6-31G(d)) were carried out.
- ItemIsolation of phytochemical constituents from hunteria umbellata k. Schum(Benin : University of Benin, 2019) Ali, Iftikhar; Falodun, Abiodun; Siyo, Baraa; Jules, Bankeu; Hussain, Hidayat; Langer, PeterHunteria umbellata K. Schum has been reported for the treatment of diabetes in Nigeria. In the present study, the ethanolic extract of dried leaves of Hunteria umbellata K. Schum was investigated for the chemical principles. The isolated pure compounds were characterized by NMR, IR and Mass spectral studies. Ursolic acid (1), oleanolic acid (2) and squalene (3) were the main constituents isolated from the extract.