title: C-Phycocyanin inhibits 2-acetylaminofluorene-induced expression of MDR1 in mouse macrophage cells: ROS mediated pathway determined via combination of experimental and In silico analysis.
abstract: We studied the effects of C-Phycocyanin (C-PC), a biliprotein from Spirulina platensis on the 2-acetylaminofluorene (2-AAF)-induced expression of MDR1, encoded by the multidrug resistance (MDR1) gene, in mouse macrophage cell line (RAW 264.7). Our experimental and In silico studies revealed a significant inhibition of 2-AAF-induced expression of MDR1 protein in C-PC treated mouse macrophage cell line. MDR1 induction by 2-AAF was dependent on ROS (reactive oxygen species)-Akt (protein kinase B)-NF-kappaB (Nuclear factor kappa B) signaling pathway. Generation of ROS, phosphorylation of Akt and corresponding nuclear translocation of NF-kappaB, the events that play a major role in the induction of MDR1 expression, were decreased significantly in C-PC treated cells. NADPH oxidase inhibitor, DPI (Diphenyl iodide), and pharmacological inhibitor of Akt, Akt inhibitor IV, also showed a reduction in MDR1 expression, although not to the same extent as C-PC mediated inhibition of MDR1 expression. To further understand the mechanism, we created a computational model of the detailed ROS-Akt-NF-kappaB pathway. C-PC was modeled purely as a ROS scavenger and this representation matched the experimental trends accurately. Also the ROS levels determined through In silico investigation showed that C-PC was more effective in reduction of MDR1 expression than inhibitors of NADPH oxidase and Akt. Our experimental and In silico studies collectively suggest that 2-AAF induces MDR1 by ROS dependent pathway and C-PC is a potential negative regulator of MDR1 expression. This down regulation of MDR1 expression, induced by xenobiotics such as 2-AAF, suggests C-PC's usefulness in overcoming the drug resistance in cellular systems.
authors.affiliation: Department of Animal Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
authors.forename: Karnati R
authors.initials: KR
authors.lastname: Roy
authors.forename: Kalle M
authors.initials: KM
authors.lastname: Arunasree
authors.forename: Amit
authors.initials: A
authors.lastname: Dhoot
authors.forename: Rachamallu
authors.initials: R
authors.lastname: Aparna
authors.forename: Gorla Venkateswara
authors.initials: GV
authors.lastname: Reddy
authors.forename: Shireen
authors.initials: S
authors.lastname: Vali
authors.forename: Pallu
authors.initials: P
authors.lastname: Reddanna
mesh_terms: D015073:2-Acetylaminofluorene / Q000008:administration & dosage*; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D003198:Computer Simulation; D004338:Drug Combinations; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological; D010798:Phycocyanin / Q000008:administration & dosage*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D004338:Drug Combinations; D017382:Reactive Oxygen Species; D010798:Phycocyanin; D015073:2-Acetylaminofluorene