Anastasios I. Birmpilis*, Panagiotis Vitsos*, Ioannis V. Kostopoulos, Lillian Williams, Kyriaki Ioannou, Pinelopi Samara, Chrysoula-Evangelia Karachaliou, Ioannis F. Voutsas, Elena Alyfanti, Nikolaos Angelis, Nikolaos G. Gavalas, Themis Gkraikou, Niki Kappa, Eleftheria Klagkou, Persefoni Klimentzou, Spiridoula Nikou, Nikos E. Papaioannou, Margarita Skopeliti, David Toukli, Meletios-Athanasios Dimopoulos, Aristotelis Bamias, Evangelia Livaniou, Hubert Kalbacher, Ourania E. Tsitsilonis* and Wolfgang Voelter Pages 6463 - 6478 ( 16 )
Background: Members of the α-thymosin family have long been studied for their immunostimulating properties. Among them, the danger-associated molecular patterns (DAMPs) prothymosin α (proTα) and its C-terminal decapeptide proTα(100–109) have been shown to act as immunomodulators in vitro, due to their ability to promote T helper type 1 (Th1) responses. Recently, we verified these findings in vivo, showing that both proTα and proTα(100-109) enhance antitumor-reactive T cell-mediated responses.
Methods: In view of the eventual use of proTα and proTα(100-109) in humans, we investigated their safety profile in silico, in human leukocytes and cancer cell lines in vitro, and in immunocompetent mice in vivo, in comparison to the proTα derivative thymosin alpha 1 (Τα1), a 28-mer peptide extensively studied for its safety in clinical trials.
Results: In silico prediction via computational tools showed that all three peptide sequences likely are non-toxic or do not induce allergic regions. In vitro, pro- Tα, proTα(100-109) and Tα1 did not affect the viability of human cancer cell lines and healthy donor-derived leukocytes, did not promote apoptosis or alter cell cycle distribution. Furthermore, mice injected with proTα, proTα(100-109) and Tα1 at doses equivalent to the suggested dose regimen of Tα1 in humans, did not show signs of acute toxicity, whereas proTα and proTα(100-109) increased the levels of proinflammatory and Th1- type cytokines in their peripheral blood.
Conclusion: Our preliminary findings suggest that proTα and proTα(100-109), even at high concentrations, are non-toxic in vitro and in an acute toxicity model in vivo; moreover, we show that the two peptides retain their immunomodulatory properties in vivo and, eventually, could be considered for therapeutic use in humans.
DAMP, prothymosin alpha, in vivo toxicity, immunomodulation, thymic peptides, thymosin alpha 1.
Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, NCSR “Demokritos”, Agia Paraskevi, 15310 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Department of Clinical Therapeutics, School of Medicine, National and Kapodistrian University of Athens, 11528 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, NCSR “Demokritos”, Agia Paraskevi, 15310 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Department of Clinical Therapeutics, School of Medicine, National and Kapodistrian University of Athens, 11528 Athens, Department of Clinical Therapeutics, School of Medicine, National and Kapodistrian University of Athens, 11528 Athens, Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, NCSR “Demokritos”, Agia Paraskevi, 15310 Athens, Interfaculty Institute of Biochemistry, Eberhard Karls Universität Tübingen, 72076 Tübingen, Department of Biology, School of Science, National and Kapodistrian University of Athens, 15784 Athens, Interfaculty Institute of Biochemistry, Eberhard Karls Universität Tübingen, 72076 Tübingen