The role of exosomes in transferal of acquired cisplatin resistance

Background: A major obstacle when treating cancer patients with cisplatin is that cancer often acquires cisplatin resistance during treatment, resulting in poor patient survival time. One important mechanism of cisplatin resistance is thought to be transferal of pro-survival characteristics, such as increased expression of the anti-apoptotic heat shock protein 70 (HSP70) through release and uptake of exosomes, small bioparticles that contain proteins, messenger RNA (mRNA) or micro RNA (miR). Methods: We studied the morphology and size distribution of exosomes released by malignant pleural mesothelioma (MPM) and non-small cell lung cancer cells through confocal microscopy and nanoparticle tracking analysis. We assessed whether exosomes extracted from cells of the studied cell lines could fuse with the plasma membrane and introduce HSP70 to the cell surface through confocal microscopy. Results: Exosomes secreted from cisplatin-resistant P31res cells and H1299res cells were able to fuse with the plasma membrane and present HSP70 on the surface of cells from the corresponding cell line (P31 and H1299) as well as the cells they originated from. Conclusions: Cisplatin resistance transferal through exosomes may lead to better future treatment alternatives.