title: DNA binding and apoptotic induction ability of harmalol in HepG2: Biophysical and biochemical approaches.
abstract: Harmalol administration caused remarkable reduction in proliferation of HepG2 cells with GI50 of 14.2 μM, without showing much cytotoxicity in embryonic liver cell line, WRL-68. Data from circular dichroism (CD) and differential scanning calorimetric (DSC) analysis of harmalol-CT DNA complex shows conformational changes with prominent CD perturbation and stabilization of CT DNA by 8 °C. Binding constant and stoichiometry was calculated using the above biophysical techniques. The Scatchard plot constructed from CD data showed cooperative binding, from which the cooperative binding affinity (K'ω) of 4.65 ± 0.7 × 10(5) M(-1), and n value of 4.16 were deduced. The binding parameter obtained from DSC melting data was in good agreement with the above CD data. Furthermore, dose dependent apoptotic induction ability of harmalol was studied in HepG2 cells using different biochemical assays. Generation of ROS, DNA damage, changes in cellular external and ultramorphology, alteration of membrane, formation of comet tail, decreased mitochondrial membrane potential and a significant increase in Sub Go/G1 population made the cancer cell, HepG2, prone to apoptosis. Up regulation of p53 and caspase 3 further indicated the apoptotic role of harmalol.
authors: Department of Zoology, University of Kalyani, Nadia, West Bengal, 741235, India.
authors: Sarita
authors: S
authors: Sarkar
authors: Department of Zoology, University of Kalyani, Nadia, West Bengal, 741235, India.
authors: Paromita
authors: P
authors: Bhattacharjee
authors: Department of Zoology, University of Kalyani, Nadia, West Bengal, 741235, India. Electronic address: kakali_bhadra2004@yahoo.com.
authors: Kakali
authors: K
authors: Bhadra
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D015415:Biomarkers / Q000378:metabolism; D055592:Biophysical Phenomena / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D020552:Comet Assay; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004249:DNA Damage; D053938:DNA Fragmentation / Q000187:drug effects; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D006246:Harmaline / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D056945:Hep G2 Cells; D006801:Humans; D007150:Immunohistochemistry; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D009690:Nucleic Acid Conformation; D011419:Propidium / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D044366:Transition Temperature; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D017304:Annexin A5; D015415:Biomarkers; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; C007904:harmalol; D011419:Propidium; D004247:DNA; C427203:calf thymus DNA; D006246:Harmaline; D053148:Caspase 3; D016650:Fluorescein-5-isothiocyanate; D000111:Acetylcysteine
keywords: Apoptosis; CD; Comet assay; DSC; Harmalol-DNA interaction; ROS