PAPER www rsc org loc Lab on a Chip A micro cell culture analog mCCA with 3 D hydrogel culture of multiple cell lines to assess metabolism dependent cytotoxicity of anti cancer drugs Jong Hwan Sunga and Michael L Shuler ab Received 29th August 2008 Accepted 26th January 2009 First published as an Advance Article on the web 20th February 2009 DOI 10 1039 b901377f A microfluidic device with 3 D hydrogel cell cultures has been developed to test the cytotoxicity of anticancer drugs while reproducing multi organ interactions In this device a micro cell culture analog mCCA cells embedded in 3 D hydrogels are cultured in separate chambers representing the liver tumor and marrow which are connected by channels mimicking blood flow While the microfluidic network provides a platform for mimicking the pharmacokinetic and pharmacodynamic profiles of a drug in humans the 3 D hydrogel provides a more physiologically realistic environment to mimic the tissue than monolayer culture Colon cancer cells HCT 116 and hepatoma cells HepG2 C3A were encapsulated in Matrigel and cultured in the tumor and the liver chamber in a mCCA respectively Myeloblasts Kasumi 1 were encapsulated in alginate in the marrow chamber a stiffer hydrogel was necessary to prevent cell migration out of the matrix The cytotoxic effect of Tegafur an oral prodrug of 5 fluorouracil 5 FU on each cell line was tested using the mCCA with cell embedded hydrogel The comparison of experimental results using a 96 well microtiter plate and a mCCA demonstrated that the mCCA was able to reproduce the metabolism of Tegafur to 5 FU in the liver and consequent death of cells by 5 FU while the cultures in a 96 well microtiter plate were unable to do so The mCCA utilizing 3 D hydrogel cell cultures has potential as a platform for pharmacokinetic based drug screening in a more physiologically realistic environment Introduction Drug discovery is a multi disciplinary process which takes a significant amount of time and money Despite continuing advances in technologies such as combinatorial chemistry and high throughput screening HTS pharmaceutical companies have been suffering from decreasing productivity during the past decade 1 It has been speculated that the major causes of attrition in the drug development process are unforeseen toxicity and the lack of efficacy which account for about 50 of the failures 2 Furthermore a large fraction of drug candidates about 23 fail at the later stages of drug development process after the majority of the drug development costs have been incurred 1 Considering that the cost of clinical development of a drug is massive in the range of US 500 to US 2000 million 3 being able to predict the efficacy and the toxicity of drugs in the earlier preclinical stages would greatly improve the productivity of the drug development process During the preclinical phase the evaluation of a New Chemical Entity NCE is typically performed using in vitro cell based assays which are readily adaptable to a high throughput format 4 However current in vitro cell based assays have limitations due primarily to the fact that only a single cell type is used in the assay and multi organ interactions cannot be observed a School of Chemical and Biomolecular Engineering Cornell University Ithaca NY 14853 USA b Department of Biomedical Engineering 115 Weill Hall Cornell University Ithaca NY 14853 USA E mail mls50 cornell edu Fax 1 607 255 7330 Tel 1 607 255 7577 This journal is The Royal Society of Chemistry 2009 Also current multi well plate systems are static systems in which cells are simply incubated with medium containing test compounds as a bolus dose The in vivo situation is much more complicated after administration drugs undergo a complex process of absorption distribution metabolism and elimination ADME which is a time dependent process Consequently changes in pharmacokinetic pharmacodynamic profiles due to organ interactions in vivo may result in revelation of unpredicted toxicity or lack of efficacy that would otherwise not become apparent until later stages of drug development The ADME characteristics and the pharmacological effect of drugs can be analyzed by mathematical simulation such as physiologically based pharmacokinetic PBPK and pharmacodynamic PD modeling 5 Pharmacokinetics PK refers to the concentration profiles of a drug in the body after administration whereas pharmacodynamics PD refers to the pharmacological effect of a drug In PBPK modeling separate compartments are assigned for key organs or tissues which are connected by blood flow and differential equations are used to solve reactive mass balances for the drug and metabolites in each compartment PD models quantitatively predict the pharmacological effect of a drug by assuming a function which relates the effect of a drug E to a drug concentration at the target site C Integration of PBPK and PD models has been recognized as an approach to relate a dosing regimen to a final pharmacological effect 6 For example the growth kinetics of tumor in the rat could be predicted from a dosing regimen of anti cancer drugs 7 8 However one limitation of PK PD modeling is the possibility of inaccurate Lab Chip 2009 9 1385 1394 1385 predictions due to an unknown mechanism of action or secondary effects in other tissues Also the problem of finding accurate parameters for the model has prevented the wider application of PK PD modeling in a drug development process Recent advances in combining microfabrication with cell culture technology resulted in the rise of a new research field often referred to as cells on chip technology which has allowed researchers to have precise control over in vitro biological systems with microscale resolution 9 10 One prominent example is a 3 D cellular microarray reported by Lee et al which uses a combination of cell microarray referred to as Datachip by the authors and enzyme microarray on a glass slide Metachip to analyze the metabolism and the toxicity of a drug in vitro 11 Although this in vitro system can examine specific aspects of metabolism dependent toxicity it does not fully reproduce the dynamics of complex multi organ interactions in vivo such as the simultaneous metabolism and recirculation of metabolites We previously reported the development of a micro cell culture analog mCCA device as a physical realization of a PBPK model to reproduce the PK PD profiles of a drug in vitro 12 13 On a 2 5 by 2 5 cm silicon chip different cell lines
View Full Document
Unlocking...