title: Effect of 3D matrix compositions on the efficacy of EGFR inhibition in pancreatic ductal adenocarcinoma cells.
abstract: Therapeutics to inhibit signaling of epidermal growth factor receptor (EGFR) has been suggested as a potential treatment for pancreatic cancers, and two-dimensional (2D) cell culture techniques are commonly used to identify and/or verify the therapeutic efficacy of EGFR inhibitors. However, drug targets identified from conventional cell culture techniques may not exhibit desired functions when these drugs are tested in animal studies, in large part due to the complicated tumor microenvironments. Hence, it is crucial to develop a biomimetic cell culture system capable of recapitulating aspects of tumor niches for studying cancer cell fate processes under the influence of various environmental stimuli. In this study, we utilized a versatile PEG-peptide hydrogel system to demonstrate the influence of matrix properties and EGFR inhibition on the growth of a pancreatic ductal adenocarcinoma cell line (PANC-1). PANC-1 cells were encapsulated in 8-arm PEG-norbornene (PEG8NB) hydrogels cross-linked by matrix metalloproteinase (MMP) sensitive peptide (MMP(Linker)) using thiol-ene photoclick chemistry. In soft hydrogels (G' ~ 2 kPa), cells retained high initial viability and formed clusters after prolonged culture, whereas cells encapsulated in stiff hydrogels (G' ~ 12 kPa) exhibited lower initial viability and reduced proliferation. While the immobilization of an EGFR peptide inhibitor, Asn-Tyr-Gln-Gln-Asn or NYQQN, in soft hydrogels did not cause cell death, this peptide induced significant cell apoptosis when immobilized in stiff hydrogels. Western blotting results showed that cell death was due to reduced expression of EGFR and Akt in stiff hydrogels under the influence of immobilized NYQQN peptide. These results shed light on the importance and non-negligible role of matrix properties on the efficacy of antitumor drugs.
authors.affiliation: Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana 46202, United States.
authors.forename: Chang Seok
authors.initials: CS
authors.lastname: Ki
authors.forename: Han
authors.initials: H
authors.lastname: Shih
authors.forename: Chien-Chi
authors.initials: CC
authors.lastname: Lin
mesh_terms: D000595:Amino Acid Sequence; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D040761:Biomimetic Materials; D021441:Carcinoma, Pancreatic Ductal; D018929:Cell Culture Techniques; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D057930:Click Chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry; D004354:Drug Screening Assays, Antitumor / Q000379:methods*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry* / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000737:chemistry*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D059016:Tumor Microenvironment
chemical_list: D000970:Antineoplastic Agents; D003432:Cross-Linking Reagents; D020100:Hydrogels; D009842:Oligopeptides; C587254:asparagyl-tyrosyl-glutaminyl-glutaminyl-asparagine; D011092:Polyethylene Glycols; C512478:EGFR protein, human; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt