title: Differential protein expression and novel biomarkers related to 5-FU resistance in a 3D colorectal adenocarcinoma model.
abstract: The multicellular spheroid (MCS) is an in vitro model which is highly representative of the avascular region of solid tumors by reflecting microenvironmental conditions in vivo. Hence, it is considered the most appropriate model for studying drug resistance. We compared chemosensitivity to 5-fluorouracil (5-FU) and differential protein expression between the 3D MCS model and the 2D monolayers using DLD-1 cells. We analyzed several significant signaling molecules through western blot analysis. Although various changes in the expression level were observed depending on the samples, we did not obtained remarkable findings. Notably, the level of p-mTOR decreased upon 5-FU exposure in the monolayers, while its level was higher in the MCSs. Nine novel proteins were identified by 2-DE and MALDI-TOF analysis for exhibiting differential expression between the MCS model and the monolayers. Among these, collapsin response mediator protein 2 (CRMP-2), DNA replication complex GINS protein PSF2 (PSF-2) and selenium-binding protein 1 (SBP-1) were notable not only for their differential expression but also for decreased expression following 5-FU exposure, indicating their possible roles as novel biomarkers for sensitivity (CRMP-2, PSF-2) as well as resistance (SBP-1) to 5-FU. Overall, the present study demonstrated greater 5-FU resistance in human colorectal cancer cells grown as MCSs compared to monolayers and identified p-mTOR, CRMP-2, PSF-2 and SBP-1 as novel potential biomarkers of 5-FU chemosensitivity/resistance for human colorectal cancer, findings which warrant further investigation.
authors: Department of Biomedical Sciences, School of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea.
authors: Sang-Hak
authors: SH
authors: Lee
authors: Department of Biomedical Sciences, School of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea.
authors: Jae Kook
authors: JK
authors: Nam
authors: Department of Biomedical Sciences, School of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea.
authors: Jong-Kook
authors: JK
authors: Park
authors: Department of Biomedical Sciences, School of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea.
authors: Joo-Ho
authors: JH
authors: Lee
authors: Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 609-735, Republic of Korea.
authors: Do Sik
authors: do S
authors: Min
authors: Department of Biomedical Sciences, School of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea.
authors: Hyo-Jeong
authors: HJ
authors: Kuh
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism*; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D045744:Cell Line, Tumor; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000378:metabolism*; D019008:Drug Resistance, Neoplasm; D005472:Fluorouracil / Q000494:pharmacology*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D040901:Proteomics; D051137:Selenium-Binding Proteins / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D059016:Tumor Microenvironment
chemical_list: D000964:Antimetabolites, Antineoplastic; D014408:Biomarkers, Tumor; D002868:Chromosomal Proteins, Non-Histone; C556406:GINS2 protein, human; D036341:Intercellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; C495175:SELENBP1 protein, human; D051137:Selenium-Binding Proteins; C095114:collapsin response mediator protein-2; C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases; D005472:Fluorouracil