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[Sensitivity of the retinal pigment epithelium to spindle poisons]
Purpose:
The function of RPE is well known in PVR. Pharmacological agents have been extensively studied both experimentally and clinically. Few reports have detailed the interactions of antimitotic drugs on the microtubule network. The aim of this study is to visualize by indirect immunofluorescence the effects of colchicine and paclitaxel on the microtubule network of cultured pig RPE cells in interphase.
Methods:
Pigs were killed at the slaughter-house, their eyes were enucleated. RPE cells were isolated and cultured. RPE cells were plated onto glass cover-slips at a density of 2,000,000 cells/ml, cultured and treated with the drugs during 4 and 24 hours at 37 degrees C at different concentrations. Immunofluorescence reaction was developped using antitubulin and fluoresceinated anti-mouse antibodies. The cytoskeletons were visualized employing a Zeiss photomicroscope equipped with epiilumination, a 63 x lens and appropriate filters for fluoresceine.
Results:
The cytoplasmic microtubules of RPE cells were disrupted in a concentration and time-dependant manner by colchicine. Between 10 and 100 nm Veveral degrees of depolymarization of the microtubule network were observed. Paclitaxel between 1 micron and 10 microns was found to induce several degrees of microtubule "bundling" after 4 and 24 hours of incubation. Actin network was modified neither by colchicine and paclitaxel used in the same conditions.
Conclusions:
The results show that low doses of antimitotic drugs inhibit the microtubule network formation by depolymerization (colchicine) or stabilize it (paclitaxel). These actions inhibit cell division, which is one of the mechanisms implicated in PVR.
Insights
Colchicine depolymerizes microtubules, while paclitaxel bundles them in cultured pig RPE cells. These antimitotic drug effects on the microtubule network may inhibit cell division, a factor in proliferative vitreoretinopathy (PVR).
Area of Science:
- Cell Biology
- Pharmacology
- Ophthalmology
Context:
- Proliferative vitreoretinopathy (PVR) involves retinal pigment epithelium (RPE) cells.
- Antimitotic drugs are studied for PVR treatment.
- Microtubule network interactions with these drugs are not fully understood.
Purpose:
- To visualize the effects of colchicine and paclitaxel on the microtubule network of cultured pig RPE cells.
- To understand how antimitotic drugs impact RPE cell cytoskeleton.
Summary:
- Colchicine disrupted RPE cell microtubules in a dose- and time-dependent manner, causing depolymerization.
- Paclitaxel induced microtubule bundling in RPE cells.
- Neither drug affected the actin network under tested conditions.
Impact:
- Demonstrates distinct mechanisms of antimitotic drugs on microtubule dynamics.
- Provides insights into cellular processes relevant to PVR.
- Highlights potential therapeutic targets for inhibiting RPE cell proliferation.