Identification and characterization of interleukin-13 receptor in human medulloblastoma and targeting these receptors with interleukin-13-pseudomonas exotoxin fusion protein.
OBJECTIVE
To identify and characterize the subunit structure of interleukin-13 receptor (IL-13R) in human medulloblastoma cell lines and target them with a chimeric fusion protein consisting of interleukin-13 and Pseudomonas exotoxin (termed as IL-13 cytotoxin).


METHODS
Five human medulloblastoma cell lines were examined for the expression of IL-13R subunits at the mRNA and protein levels by reverse transcriptase-polymerase chain reaction (RT-PCR) and indirect immunofluorescence studies, respectively. In addition, IL-13 cytotoxin-induced cytotoxicity was examined in these medulloblastoma cell lines by measuring protein synthesis inhibition.


RESULTS
All five medulloblastoma cell lines expressed mRNA and proteins for IL-4Ra and IL-13Ra1 chains, whereas three of the cell lines also showed the presence of IL-13Ra2. mRNA or protein for IL-2gc chain was not detected in any of the cell lines. Consistent with the expression of IL-13Ra2 chain, IL-13 cytotoxin was highly and specifically cytotoxic to three of five medulloblastoma cell lines. The sensitivity of medulloblastoma cell lines to IL-13 cytotoxin could be completely eliminated by concurrent incubation with excess of IL-13, but not with IL-2 or IL-4.


CONCLUSIONS
These studies establish IL-13R, in particular IL-13Ra2, as a medulloblastoma-associated target for IL-13 cytotoxin therapy. IL-13 cytotoxin may be useful for medulloblastoma therapy. Alternatively, IL-13Ra2 may serve as a tumor-specific antigen for active immunotherapy.
Joshi
Bharat H
BH
Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD, USA.
Leland
Pamela
P
Puri
Raj K
RK
D002528:Cerebellar Neoplasms / Q000188:drug therapy / Q000473:pathology*; D003603:Cytotoxins / Q000494:pharmacology*; D005098:Exotoxins / Q000494:pharmacology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D053661:Interleukin-13 Receptor alpha1 Subunit; D008297:Male; D008527:Medulloblastoma / Q000188:drug therapy / Q000473:pathology*; D011549:Pseudomonas / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D018123:Receptors, Interleukin / Q000032:analysis*; D053660:Receptors, Interleukin-13; D011993:Recombinant Fusion Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D014407:Tumor Cells, Cultured / Q000187:drug effects
D003603:Cytotoxins; D005098:Exotoxins; C508181:IL13RA1 protein, human; D053661:Interleukin-13 Receptor alpha1 Subunit; D012333:RNA, Messenger; D018123:Receptors, Interleukin; D053660:Receptors, Interleukin-13; D011993:Recombinant Fusion Proteins