Fig. 4

Mesothelioma stem cells are more resistant to chemotherapy or radiation treatment in vitro. a The majority of highly enriched RN5-EOS-Puro2 cells (2 μg/ml for 14 days) were GFP-positive as shown in the histograms (blue curve) if compared with the unselected parental RN5-EOS cells (red curve). b RN5-EOS-Puro2 cells were treated with cisplatin or γ-ray radiation and were more resistant. c, d Untreated parental RN5-EOS cells and RN5-EOS-Puro2 cells were treated with cisplatin or γ-ray radiation. Cisplatin and radiation resulted in significant increases of the GFP-positive cell populations; in the selected MSC-enriched population, only cisplatin (alone or in combination with irradiation) slightly increased the fraction of GFP⁺ cells e) RN5-EOS-Puro2 cells express high levels of GFP (green), even after treatment with 15 Gy γ-ray (RT15Gy) or cisplatin (Cis) 5 μg/ml, almost similar as is observed in RN5-EOS-Puro2 cells not subjected to any treatment. Actin immunoflurescence is shown for the outline of cells (red) and DAPI was used to stain nuclei (blue). A merged image is shown in the right lower corner