title: Resistance to neoplastic transformation of ex-vivo expanded human mesenchymal stromal cells after exposure to supramaximal physical and chemical stress.
abstract: The risk of malignant transformation of ex-vivo expanded human mesenchymal stromal cells (huMSCs) has been debated in the last years; however, the biosafety of these cells after exposure to supramaximal physical and chemical stress has never been systematically investigated.We established an experimental in vitro model to induce supramaximal physical (ionizing radiation, IR) and chemical (starvation) stress on ex-vivo expanded bone marrow (BM)-derived huMSCs and investigated their propensity to undergo malignant transformation. To this aim, we examined MSC morphology, proliferative capacity, immune-phenotype, differentiation potential, immunomodulatory properties and genetic profile before and after stressor exposure. Furthermore, we investigated the cellular mechanisms underlying MSC response to stress. MSCs were isolated from 20 healthy BM donors and expanded in culture medium supplemented with 5% platelet lysate (PL) up to passage 2 (P2). At this stage, MSCs were exposed first to escalating doses of IR (30, 100, 200 Gy) and then to starvation culture conditions (1% PL).With escalating doses of radiation, MSCs lost their typical spindle-shaped morphology, their growth rate markedly decreased and eventually stopped (at P4-P6) by reaching early senescence. Irradiated and starved MSCs maintained their typical immune-phenotype, ability to differentiate into adipocytes/osteoblasts and to inhibit mitogen-induced T-cell proliferation. The study of the genetic profile of irradiated/starved MSCs did not show any alteration. While the induction of supramaximal stress triggered production of ROS and activation of DNA damage response pathway via multiple mechanisms, our data indicate that irradiated/starved MSCs, although presenting altered morphology/growth rate, do not display increased propensity for malignant transformation.
authors.affiliation: Department of Pediatric Hematology/Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Conforti
authors.affiliation: Department of Pediatric Hematology/Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.|Department of System Medicine, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: Starc
authors.affiliation: Department of Pediatric Hematology/Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Biagini
authors.affiliation: Department of Pediatric Hematology/Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Tomao
authors.affiliation: Department of Pediatric Hematology/Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Pitisci
authors.affiliation: Department of Pediatric Hematology/Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.
authors.forename: Mattia
authors.initials: M
authors.lastname: Algeri
authors.affiliation: Laboratory of Medical Genetics, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Sirleto
authors.affiliation: Laboratory of Medical Genetics, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Novelli
authors.affiliation: Department of Medical and Surgical Sciences for Children & Adults, Division of Oncology, University-Hospital of Modena and Reggio Emilia, Modena, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Grisendi
authors.affiliation: Department of Medical and Surgical Sciences for Children & Adults, Division of Oncology, University-Hospital of Modena and Reggio Emilia, Modena, Italy.
authors.forename: Olivia
authors.initials: O
authors.lastname: Candini
authors.affiliation: Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Cintia
authors.initials: C
authors.lastname: Carella
authors.affiliation: Department of Medical and Surgical Sciences for Children & Adults, Division of Oncology, University-Hospital of Modena and Reggio Emilia, Modena, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Dominici
authors.affiliation: Department of Pediatric Hematology/Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.|Department of Pediatrics, University of Pavia, Pavia, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Locatelli
authors.affiliation: Department of Pediatric Hematology/Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.|Current address: San Raffaele-Telethon Institute for Gene Therapy, SR-TIGET, Pediatric Immunohematology, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Maria Ester
authors.initials: ME
authors.lastname: Bernardo
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers; D002453:Cell Cycle; D002454:Cell Differentiation; D049109:Cell Proliferation; D002470:Cell Survival; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D055028:Comparative Genomic Hybridization; D004249:DNA Damage; D020869:Gene Expression Profiling; D006801:Humans; D016130:Immunophenotyping; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism* / Q000473:pathology*; D011839:Radiation, Ionizing; D017382:Reactive Oxygen Species / Q000378:metabolism; D013312:Stress, Physiological; D055815:Young Adult
chemical_list: D015415:Biomarkers; D017382:Reactive Oxygen Species
keywords: biosafety; ionizing radiation; malignant transformation; mesenchymal stromal cells; starvation