Laboratory/Clinical Translational Research

Microarrays of 41 Human Tumor Cell Lines for the Characterization of New Molecular Targets: Expression Patterns of Cathepsin B and the Transferrin Receptor
Gregory J. Wirth^a, Kathrin Schandelmaier^a, Victoria Smith^a, Angelika M. Burger^b, Heinz-Herbert Fiebig<sup>a

a</sup>Institute for Experimental Oncology, Oncotest GmbH, Freiburg, Germany, and
^bDepartment of Pharmacology and Experimental Therapeutics, Greenbaum Cancer Center, University of Maryland School of Medicine, Baltimore, Md., USA

Address of Corresponding Author

Oncology 2006;71:86-94 (DOI: 10.1159/000100476)

  Key Words

• Cathepsin B
• Cell lines
• Microarrays
• Molecular targets
• Transferrin receptor

  Abstract

In recent years the use of the microarray technology has allowed the identification of numerous cancer-related genes and proteins. Today anticancer drug discovery is mainly target driven, which requires the characterization of molecular targets in existing cell lines or xenograft models. However, this analysis is time consuming and labor intensive. In order to ease this bottleneck, we have established tissue microarrays of 41 human tumor cell lines on glass slides. The purpose of our study was to (a) establish a simple and efficient method for cell line microarray construction, (b) apply the resulting array to the profiling of cathepsin B and transferrin receptor by immunohistochemistry and (c) verify the results in separate Western blot analyses. Ten to twenty million (1-2 × 10⁷) cells were harvested without trypsinization and fixed with Bouin's solution containing 8% formalin. Cell pellets 2-5 mm in diameter were embedded in paraffin. Microarrays were assembled using a tissue arrayer. Pellet biopsies 0.6 cm in diameter were taken and arrayed in duplicate in a new recipient paraffin block. About 60 slides can be obtained from one block. Citrate buffer was used for antigen retrieval. Expression of cathepsin B was granular and located in the cytoplasm. High cathepsin B levels were detected in 2 melanomas (MEXF 514L and MEXF 276L) and in the renal cell line RXF 486L. Twenty-five cell lines showed only minimal positivity. Nine cell lines of leukemia and lymphoma, breast, ovarian, prostate and renal cancer origin were positive for the transferrin receptor, while 32 cell lines were negative. Western blotting confirmed the results obtained by immunohistochemistry. Using these cell line microarrays, cell lines overexpressing a target of interest can be selected for in vitro evaluation of specific inhibitors.

Copyright © 2006 S. Karger AG, Basel

  Author Contacts

Heinz-Herbert Fiebig
Institute for Experimental Oncology, Oncotest GmbH
Am Flughafen 12-14
DE-79108 Freiburg (Germany)
Tel. +49 761 515 5911, Fax +49 761 515 5955, E-Mail Fiebig@oncotest.de

  Article Information

Received: July 7, 2006
Accepted after revision: January 13, 2007
Published online: March 8, 2007
Number of Print Pages : 9
Number of Figures : 5, Number of Tables : 2, Number of References : 19