title: Epidermal growth factor receptor inhibitor cancer drug gefitinib modulates cell growth and differentiation of acute myeloid leukemia cells via histamine receptors.
abstract: Epidermal growth factor receptor (EGFR) inhibitor gefitinib (Iressa) is used for treating non-small cell lung cancer. Gefitinib also induces differentiation in acute myeloid leukemia (AML) cell lines and patient samples lacking EGFR by an unknown mechanism. Here we dissected the mechanism of gefitinib action responsible for its EGFR-independent effects.
  
  
  
  Signaling events were analyzed by homogenous time-resolved fluorescence and immunoblotting. Cellular proliferation and differentiation were assessed by ATP measurement, trypan blue exclusion, 5-bromo-2'-deoxyuridine incorporation and flow-cytometry. Gefitinib and G protein-coupled receptor (GPCR) interactions were assessed by β-arrestin recruitment, luciferase and radioligand competition assays. Role of histamine receptors (HR) in gefitinib actions were assessed by HR knockdown or pharmacological modulation. EGFR and HR interaction was assessed by co-immunoprecipitation.
  
  
  
  Gefitinib reduced cyclic AMP content in both AML and EGFR-expressing cells and induced ERK phosphorylation in AML cells. Dibutyryl-cAMP or PD98059 suppressed gefitinib-induced AML cell cytostasis and differentiation. Gefitinib bound to and modulated HRs with subtype selectivity. Pharmacological or genetic modulations of H2 and H4 HRs (H2R and H4R) not only suppressed gefitinib-induced cytostasis and differentiation of AML cells but also blocked EGFR and ERK1/2 inhibition in MDA-MB-231 cells. Moreover, in MDA-MB-231 cells gefitinib enhanced EGFR interaction with H4R that was blocked by H4R agonist 4-methyl histamine (4MH).
  
  
  
  HRs play critical roles in anti-cancer effects of gefitinib in both EGFR-deficient and EGFR-rich environments.
  
  
  
  We furnish fresh insights into gefitinib functions which may provide new molecular clues to its efficacy and safety issues.
authors.affiliation: Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow 226031, UP, India.
authors.forename: Manisha
authors.initials: M
authors.lastname: Yadav
authors.affiliation: Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow 226031, UP, India.
authors.forename: Abhishek Kumar
authors.initials: AK
authors.lastname: Singh
authors.affiliation: Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow 226031, UP, India.
authors.forename: Harish
authors.initials: H
authors.lastname: Kumar
authors.affiliation: Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow 226031, UP, India.
authors.forename: Geeta
authors.initials: G
authors.lastname: Rao
authors.affiliation: Department of Molecular Medicine, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raebareli Road, Lucknow 226014, UP, India.
authors.forename: Bandana
authors.initials: B
authors.lastname: Chakravarti
authors.affiliation: Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow 226031, UP, India.
authors.forename: Anagha
authors.initials: A
authors.lastname: Gurjar
authors.affiliation: Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow 226031, UP, India.
authors.forename: Shalini
authors.initials: S
authors.lastname: Dogra
authors.affiliation: Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow 226031, UP, India.
authors.forename: Sapana
authors.initials: S
authors.lastname: Kushwaha
authors.affiliation: Division of Sophisticated and Analytical Instrument Facility, CSIR-Central Drug Research Institute, Lucknow 226031, UP, India.
authors.forename: Achchhe Lal
authors.initials: AL
authors.lastname: Vishwakarma
authors.affiliation: Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow 226031, UP, India.
authors.forename: Prem Narayan
authors.initials: PN
authors.lastname: Yadav
authors.affiliation: Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow 226031, UP, India.
authors.forename: Dipak
authors.initials: D
authors.lastname: Datta
authors.affiliation: Department of Clinical Hematology and Medical Oncology, King George's Medical University, Lucknow 226003, Uttar Pradesh, India.
authors.forename: Anil Kumar
authors.initials: AK
authors.lastname: Tripathi
authors.affiliation: Division of Endocrinology, CSIR-Central Drug Research Institute, Lucknow 226031, UP, India.
authors.forename: Naibedya
authors.initials: N
authors.lastname: Chattopadhyay
authors.affiliation: Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow 226031, UP, India.
authors.forename: Arun Kumar
authors.initials: AK
authors.lastname: Trivedi
authors.affiliation: Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow 226031, UP, India. Electronic address: sanyal@cdri.res.in.
authors.forename: Sabyasachi
authors.initials: S
authors.lastname: Sanyal
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D000242:Cyclic AMP / Q000378:metabolism; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics*; D000077156:Gefitinib; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding; D051057:Proto-Oncogene Proteins c-akt / Q000096:biosynthesis / Q000235:genetics; D011799:Quinazolines / Q000008:administration & dosage*; D043562:Receptors, G-Protein-Coupled / Q000235:genetics*; D011968:Receptors, Histamine / Q000235:genetics* / Q000378:metabolism; D011970:Receptors, Histamine H2 / Q000235:genetics* / Q000378:metabolism; D000074040:Receptors, Histamine H4
chemical_list: D000970:Antineoplastic Agents; C418607:HRH4 protein, human; D011799:Quinazolines; D043562:Receptors, G-Protein-Coupled; D011968:Receptors, Histamine; D011970:Receptors, Histamine H2; D000074040:Receptors, Histamine H4; D000242:Cyclic AMP; C512478:EGFR protein, human; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt; D000077156:Gefitinib
keywords: Cancer; EGFR; GPCR; Gefitinib; Histamine receptor; Tyrosine kinase