title: Multimodal transfer of MDR by exosomes in human osteosarcoma.
abstract: Exosomes are extracellular vesicles released by both normal and tumour cells which are involved in a new intercellular communication pathway by delivering cargo (e.g., proteins, microRNAs, mRNAs) to recipient cells. Tumour-derived exosomes have been shown to play critical roles in different stages of tumour growth and progression. In this study, we investigated the potential role of exosomes to transfer the multidrug resistance (MDR) phenotype in human osteosarcoma cells. Exosomes were isolated by differential centrifugation of culture media from multidrug resistant human osteosarcoma MG-63DXR30 (Exo/DXR) and MG-63 parental cells (Exo/S). Exosome purity was examined by transmission electron microscopy and confirmed by immunoblot analysis for the expression of specific exosomal markers. Our data showed that exosomes derived from doxorubicin-resistant osteosarcoma cells could be taken up into secondary cells and induce a doxorubicin-resistant phenotype. The incubation of osteosarcoma cells with Exo/DXR decreased the sensitivity of parental cells to doxorubicin, while exposure with Exo/S was ineffective. In addition, we demonstrated that Exo/DXR expressed higher levels of MDR-1 mRNA and P-glycoprotein compared to Exo/S (p=0.03). Interestingly, both MDR-1 mRNA and P-gp increased in MG-63 cells after incubation with Exo/DXR, suggesting this as the main mechanism of exosome-mediated transfer of drug resistance. Our findings suggest that multidrug resistant osteosarcoma cells are able to spread their ability to resist the effects of doxorubicin treatment on sensitive cells by transferring exosomes carrying MDR-1 mRNA and its product P-glycoprotein.
authors.affiliation: Laboratory for Orthopaedic Pathophysiology and Regenerative Medicine, Istituto Ortopedico Rizzoli, I-40136 Bologna, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Torreggiani
authors.affiliation: Laboratory for Orthopaedic Pathophysiology and Regenerative Medicine, Istituto Ortopedico Rizzoli, I-40136 Bologna, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Roncuzzi
authors.affiliation: Laboratory for Orthopaedic Pathophysiology and Regenerative Medicine, Istituto Ortopedico Rizzoli, I-40136 Bologna, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Perut
authors.affiliation: Laboratory of Musculoskeletal Cell Biology, Istituto Ortopedico Rizzoli, I-40136 Bologna, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Zini
authors.affiliation: Laboratory for Orthopaedic Pathophysiology and Regenerative Medicine, Istituto Ortopedico Rizzoli, I-40136 Bologna, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Baldini
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000096:biosynthesis / Q000235:genetics; D017209:Apoptosis / Q000187:drug effects; D002450:Cell Communication / Q000187:drug effects; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000008:administration & dosage; D018432:Drug Resistance, Multiple / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D055354:Exosomes / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D012516:Osteosarcoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D004317:Doxorubicin