title: Capillary isoelectric-focusing immunoassays to study dynamic oncoprotein phosphorylation and drug response to targeted therapies in non-small cell lung cancer.
abstract: Developing proteomic biomarkers is valuable for evaluating therapeutic effects of drugs and generating better treatment strategies. However, conventional protein analysis is often challenging due to inadequate sample size of clinical specimens, lack of assay reproducibility, accuracy, and sensitivity. A novel capillary isoelectricfocusing (IEF) immunoassay system (NanoPro) was used to study the dynamic phosphorylation status of signaling molecules in non-small cell lung cancer (NSCLC) cells treated with EGFR tyrosine kinase and MEK inhibitors. NanoPro showed the same dynamic ERK phosphorylation as Western blotting with good assay reproducibility using 1,000 times less protein. The IEF separation in NanoPro system enables multiple protein phosphorylation isoforms to be resolved and detected simultaneously. With NanoPro, we identified a specific on-target mitogen-activated protein/extracellular signal-regulated kinase (MEK) response pattern to MEK inhibitor PD325901, which was not detectable by Western blot analysis. We also revealed a MEK2 signal that may be associated with NSCLC cell sensitivity to the EGF receptor inhibitor erlotinib, and distinguished erlotinib-sensitive cells from intrinsic as well as acquired resistant cells to erlotinib. Moreover, NanoPro could differentiate human ERK1 isoforms from the mouse isoforms based on their isoelectric point differences and showed that erlotinib effectively inhibited ERK phosphorylation in targeted human xenograft cancer cells but not in surrounding mouse stromal cells. With 8 μg of tumor aspirates, we precisely quantified the response of 18 signaling molecules to erlotinib and MEK1 inhibitor treatments in an NSCLC patient. NanoPro's higher sensitivity, better resolution of protein phosphorylation status, and reduced tissue requirement warrant NanoPro's investigation for future drug development and evaluation of drug effects of targeted therapies.
authors: Corresponding Author: Giuseppe Giaccone, Georgetown University, 3970 Reservoir Road NW, Washington, DC. gg496@georgetown.edu.
authors: Jin-Qiu
authors: JQ
authors: Chen
authors: Jih-Hsiang
authors: JH
authors: Lee
authors: Michelle A
authors: MA
authors: Herrmann
authors: Kang-Seo
authors: KS
authors: Park
authors: Madeleine R
authors: MR
authors: Heldman
authors: Paul K
authors: PK
authors: Goldsmith
authors: Yisong
authors: Y
authors: Wang
authors: Giuseppe
authors: G
authors: Giaccone
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000493:pharmacokinetics / Q000627:therapeutic use; D001562:Benzimidazoles / Q000627:therapeutic use; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D000069347:Erlotinib Hydrochloride; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D008207:Lymphatic Metastasis; D048370:MAP Kinase Kinase 2 / Q000037:antagonists & inhibitors / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D051379:Mice; D008819:Mice, Nude; D058990:Molecular Targeted Therapy; D009374:Neoplasms, Experimental; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000493:pharmacokinetics / Q000627:therapeutic use*; D011799:Quinazolines / Q000493:pharmacokinetics / Q000627:therapeutic use*
chemical_list: C517975:AZD 6244; D001562:Benzimidazoles; D015513:Oncogene Proteins; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D000069347:Erlotinib Hydrochloride; D048049:Extracellular Signal-Regulated MAP Kinases; D048370:MAP Kinase Kinase 2
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