Aminolevulinic acid-mediated photodynamic therapy of human meningioma: an in vitro study on primary cell lines.
OBJECTIVE
Five-aminolevulinic acid (5-ALA)-induced porphyrins in malignant gliomas are potent photosensitizers. Promising results of ALA-PDT (photodynamic therapy) in recurrent glioblastomas have been published. Recently, 5-ALA-induced fluorescence was studied in meningioma surgery. Here, we present an experimental study of ALA-PDT in an in vitro model of primary meningioma cell lines.


METHODS
We processed native tumor material obtained intra-operatively within 24 h for cell culture. Epithelial membrane antigen (EMA) immunohistochemistry was performed after the first passage to confirm that cells were meningioma cells. For 5-ALA-PDT treatment, about 5000 cells per well were seeded in 20 wells of a blank 96-well plate. Each block of 4 wells was inoculated with 150 µL of 0, 25, 50 and 100 µg/mL 5-ALA solutions; one block was used as negative control without 5-ALA and without PDT. Following incubation for 3 h PDT was performed using a laser (635 nm, 18.75 J/cm²). The therapeutic response was analyzed by the water soluble tetrazolium salt (WST-1) cell viability assay 90 min after PDT.


RESULTS
5-ALA-PDT was performed in 14 primary meningioma cell lines. EMA expression was verified in 10 primary cell cultures. The remaining 4 were EMA negative and PDT was without any effect in these cultures. All 10 EMA-positive cell lines showed a significant and dose-dependent decrease in viability rate (p < 0.001). Cell survival at 5-ALA concentrations of 12.5, 25, 50 and 100 μg/mL was 96.5% ± 7.6%, 67.9% ± 29.9%, 24.0% ± 16.7% and 13.8% ± 7.5%, respectively. For the negative controls (no 5-ALA/PDT and ALA/no PDT), the viability rates were 101.72% ± 3.5% and 100.17% ± 3.6%, respectively. The LD50 for 5-ALA was estimated between 25 and 50 µg/mL.


CONCLUSIONS
This study reveals dose-dependent cytotoxic effects of 5-ALA-PDT on primary cell lines of meningiomas. Either 5-ALA or PDT alone did not affect cell survival. Further efforts are necessary to study the potential therapeutic effects of 5-ALA-PDT in vivo.
Department of Neurosurgery, Universitätsklinikum Düsseldorf, Heinrich Heine Universität, 40225 Düsseldorf, Germany. mustafa.el-khatib@ukb.uni-bonn.de.
Mustafa
M
El-Khatib
Department of Neurosurgery, Universitätsklinikum Düsseldorf, Heinrich Heine Universität, 40225 Düsseldorf, Germany. carolin.tepe@uni-duesseldorf.de.
Carolin
C
Tepe
Department of Neurosurgery, Universitätsklinikum Düsseldorf, Heinrich Heine Universität, 40225 Düsseldorf, Germany. Brigitte.Senger@med.uni-duesseldorf.de.
Brigitte
B
Senger
Department of Neurosurgery, Universitätsklinikum Düsseldorf, Heinrich Heine Universität, 40225 Düsseldorf, Germany. Maxine.Dibue@med.uni-duesseldorf.de.|Center for Molecular Medicine, Universität zu Köln, 50931 Cologne, Germany. Maxine.Dibue@med.uni-duesseldorf.de.|Institute for Neurophysiology, Universität zu Köln, 50931 Cologne, Germany. Maxine.Dibue@med.uni-duesseldorf.de.
Maxine
M
Dibué-Adjei
Department of Neuropathology, Regensburg University Hospital, 93042 Regensburg, Germany. markus.riemenschneider@ukr.de.|Wilhelm Sander-NeuroOncology Unit, Regensburg University Hospital, 93042 Regensburg, Germany. markus.riemenschneider@ukr.de.
Markus Johannes
MJ
Riemenschneider
Department of Neurosurgery, Universitätsklinikum Münster, Westfälische Wilhelms-Universität, 48149 Münster, Germany. walter.stummer@ukmuenster.de.
Walter
W
Stummer
Department of Neurosurgery, Universitätsklinikum Düsseldorf, Heinrich Heine Universität, 40225 Düsseldorf, Germany. Hans-Jakob.Steiger@med.uni-duesseldorf.de.
Hans Jakob
HJ
Steiger
Department of Neurosurgery, Universitätsklinikum Düsseldorf, Heinrich Heine Universität, 40225 Düsseldorf, Germany. cornelius@hhu.de.
Jan Frédérick
JF
Cornelius
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000622:Aminolevulinic Acid / Q000494:pharmacology / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008577:Meningeal Neoplasms / Q000188:drug therapy* / Q000473:pathology; D008579:Meningioma / Q000188:drug therapy* / Q000473:pathology; D008875:Middle Aged; D018396:Mucin-1 / Q000378:metabolism; D010778:Photochemotherapy
D018396:Mucin-1; D000622:Aminolevulinic Acid