Artikel
Efficacy of 5-aminolevulinic acid based photodynamic therapy in vitro in immortalized and in primary human pituitary adenoma cell cultures
Suche in Medline nach
Autoren
Veröffentlicht: | 2. Juni 2015 |
---|
Gliederung
Text
Objective: Although pituitary adenomas are benign tumors, complete surgical resection is not always possible and may cause recurrence. As adjuvant treatments may have drawbacks, alternative new treatment options should be investigated. 5-aminolevulinic acid based photodynamic therapy (5-ALA PDT) showed promising experimental and clinical results for gliomas. The present study tested the efficacy of 5-ALA PDT in vitro on an immortalized cell line (Group I) and in primary human pituitary adenoma cell cultures (Group II).
Method: In Group I experiments were carried out on an immortalized rat pituitary adenoma cell line (GH3). The cultured cells were treated with different 5-ALA concentrations ranging from 7.5 - 16.5 microg/ml. In Group II human pituitary adenoma cell cultures were obtained from surgically resected adenoma tissue (n=10). These were incubated with 5-ALA concentrations from 12.5 - 100 microg/ml. The concentration ranges had been determined in preliminary dose-finding tests. The rest of the protocol was identical: for both groups incubation time was four hours and PDT was performed by exposition to laser light (635nm, 625 sec, 18.75 J/cm2). Cell viability was examined one hour after PDT by WST-1 assay. Negative control groups were realized.
Results: In both groups PDT showed a 5-ALA concentration-dependant effect on cell death. In Group I lower 5-ALA concentrations were necessary to destroy all cells as compared to Group II. Moreover, in Group II, the different subtypes of human adenomas showed different sensitivities to 5-ALA-based PDT (secreting vs. non-secreting). Especially corticotroph adenomas were highly sensitive to 5-ALA PDT.
Conclusions: The GH3 cell line was an useful in vitro model to optimize different PDT parameters. Human pituitary adenoma cells could also be killed by 5-ALA PDT, however they necessitated higher 5-ALA concentrations. Furthermore, the results suggested different 5-ALA sensitivities of different human adenoma cell types. More experiments are necessary to confirm these preliminary results.