title: Micropillar arrays as potential drug screens: Inhibition of micropillar-mediated activation of the FAK-Src-paxillin signaling pathway by the CK2 inhibitor CX-4945.
abstract: Here, we demonstrate the possible applications of micropillar arrays in screening anti-metastasis drugs. Human lung adenocarcinoma A549 cells incubated in multiwell plates containing micropillars exhibited markedly different physical/biochemical behavior depending on pillar dimensions. In particular, A549 cells grown in plates containing 2-μm diameter, 16-μm pitched pillar arrays showed epithelial-to-mesenchymal transition (EMT)-like behavior; cell body elongation, and highly increased activation of the focal adhesion kinase (FAK)-Src-paxillin signaling cascade. FAK is the most prominent kinase involved in dynamic regulation of the actin cytoskeleton and cell adhesion, migration, and invasion. Activation of FAK, a hallmark of cancer cell adhesion and migration, is normally induced by various growth factors, such as transforming growth factor-β (TGF-β). Here, we found that pillar-mediated activation of signaling molecules mimicked that induced by TGF-β. Notably, micropillar arrays with specific dimensions accelerated the elongation of cells, an effect linked to the activation of signaling molecules related to EMT. Micropillar-induced FAK activation could be arrested by the casein kinase-2 (CK2) inhibitor CX-4945, a drug candidate with activity against TGF-β-induced cancer cell metastasis, demonstrating the possibility of using inorganic microstructures for cell-based drug screening.
  
  
  CONCLUSIONS
  In this work, we have fabricated flexible substrates with regular arrays of micrometersized pillars, and used them to grow A549 human lung adenocarcinoma cells. Cells exhibit dramatically different behavior depending on the intervals of pillars. Especially, cells grown in certain pillar structures show epithelial-to mesenchmal transition (EMT)-like morphology and related molecules, which is similar to the activation obtained using expensive cytokine TGF-β. Based on the fact that pillar arrays may activate EMT like transition, screening of anti-cancer drug using pillar arrays have demonstrated as well in our work. Our study confirms that mechanical stimulation may exert similar effects with chemical stimulation, and such mechanical structures could be used as a large-scale drug screening platforms. Cell morphogenesis on engineered substrate is not new, but the present work could be distinguished with its unique fabrication process that can mass produce the structures and it could be applied for high-throughput drug screening. Also, we suggest the formation of focal adhesions on pillar structures and consequent strain as the possible mechanism behind the observed EMT-like transition. Currently, we are working on full-scale profiling of metabolomics and proteomics of cells grown in large-scale pillar arrays as well.
authors: Laboratory of Translational Therapeutics, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-343, Republic of Korea.
authors: Jiyeon
authors: J
authors: Kim
authors: Advanced Materials Division, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-343, Republic of Korea.
authors: Won Jin
authors: WJ
authors: Choi
authors: Laboratory of Translational Therapeutics, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-343, Republic of Korea; Department of Biology, Chungnam National University, Daejeon 305-510, Republic of Korea.
authors: Seong-Hee
authors: SH
authors: Moon
authors: Research Center for Convergence Nanotechnology, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-343, Republic of Korea.
authors: Jongjin
authors: J
authors: Jung
authors: Research Center for Convergence Nanotechnology, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-343, Republic of Korea.
authors: Joung Kyu
authors: JK
authors: Park
authors: Laboratory of Translational Therapeutics, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-343, Republic of Korea. Electronic address: hwan@krict.re.kr.
authors: Seong Hwan
authors: SH
authors: Kim
authors: Advanced Materials Division, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-343, Republic of Korea. Electronic address: jolee@krict.re.kr.
authors: Jeong-O
authors: JO
authors: Lee
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D001681:Biological Assay / Q000295:instrumentation / Q000379:methods; D047390:Casein Kinase II / Q000037:antagonists & inhibitors*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor / Q000379:methods; D004789:Enzyme Activation / Q000187:drug effects; D004867:Equipment Design; D019544:Equipment Failure Analysis; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism*; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000473:pathology; D040542:Mechanotransduction, Cellular / Q000187:drug effects*; D009287:Naphthyridines / Q000008:administration & dosage*; D051419:Paxillin / Q000378:metabolism; D010619:Phenazines; D046888:Tissue Array Analysis / Q000295:instrumentation* / Q000379:methods; D016896:Treatment Outcome; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D009287:Naphthyridines; D051419:Paxillin; D010619:Phenazines; C555142:silmitasertib; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human; D019061:src-Family Kinases; D047390:Casein Kinase II
keywords: Drug screening; Epithelial-to-mesenchymal transition (EMT); Focal adhesion; Micropillar array