Effect of the cytostatic agent idarubicin on fibroblasts of the human Tenon's capsule compared with mitomycin C

Abstract

Background/aims - To investigate the in vitro effect of a short time exposure to the anthracycline idarubicin on proliferation, protein synthesis, and motility of human Tenon's capsule fibroblasts in comparison with the antitumour antibiotic mitomycin C. Methods - After determination of effective concentrations of idarubicin, fibroblasts of the human Tenon's capsule were exposed to idarubicin or mitomycin C at concentrations ranging from 0.1 μg/ml to 1 μg/ml or from 2.5 μg/ml to 250 μg/ml, respectively, for 0.5, 2, or 5 minutes and cultured for 60 days. Cell death by apoptosis caused by idarubicin treatment was confirmed by Hoechst 33258 staining. Further proliferation was explored by cell counting and by 3H-thymidine uptake. Protein synthesis was measured by 3H-proline uptake and motility was assessed by agarose droplet motility assay. Results - Idarubicin is able to exert toxicity and to induce apoptosis during a short time exposure of 0.5 minutes at concentrations of 0.3-1 μg/ml resulting in a significant reduction in cell number compared with the control after 60 days. For mitomycin C, higher concentrations and longer expositions were necessary. Even after treatment with 1 μg/ml idarubicin or 250 μg/ml mitomycin C a few cells were able to incorporate 3H-thymidine. 3H-proline uptake up to 10 days after exposure to 0.3 μg/ml idarubicin was found not to be decreased. Cell motility was reduced after treatment with 1 μg/ml idarubicin for 5 minutes or with 250 μg/ml mitomycin C for 2 or 5 minutes. For low mitomycin C concentrations, an increase in motility was found during the first 10 days. Conclusion - Idarubicin reduces proliferation of human Tenons's capsule fibroblasts after incubation for 0.5 minutes at concentrations as low as 0.3-1 μg/ml. In comparison, mitomycin C requires longer exposure times and higher doses for equal results. Therefore, idarubicin may be useful in the prevention of glaucoma filtering surgery failure.