Sotirios P. Fortis

Dr. Sotirios P. Fortis

Cancer Immunology and Immunotherapy Center, Cancer Research Center, Saint Savas Cancer Hospital, 171 Alexandras Av., 11522 Athens, Greece

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 October 2019 in Cancer Immunology, Immunotherapy
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Journal Article
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MSMichail Sofopoulos
Michail Sofopoulos
SFSotirios P. Fortis
Sotirios P. Fortis
CVChristoforos K. Vaxevanis
Christoforos K. Vaxevanis
NSNectaria N. Sotiriadou
Nectaria N. Sotiriadou
NANiki Arnogiannaki
Niki Arnogiannaki
Constantin N. BaxevanisConstantin N. Baxevanis
Constantin N. Baxevanis

1 July 2021 in Seminars in Cancer Biology
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Journal Article
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Constantin N. BaxevanisConstantin N. Baxevanis
Constantin N. Baxevanis
SFSotirios P. Fortis
Sotirios P. Fortis
SPSonia A. Perez
Sonia A. Perez

18 April 2017 in Journal for ImmunoTherapy of Cancer
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Journal Article
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SFSotirios P. Fortis
Sotirios P. Fortis
MSMichail Sofopoulos
Michail Sofopoulos
NSNectaria N. Sotiriadou
Nectaria N. Sotiriadou
CHChristoforos Haritos
Christoforos Haritos
CVChristoforos K. Vaxevanis
Christoforos K. Vaxevanis
Constantin N. BaxevanisConstantin N. Baxevanis
Constantin N. Baxevanis
Background Tumor immune cell infiltrates are essential in hindering cancer progression and may complement the TNM classification. CD8+ and CD163+ cells have prognostic impact in breast cancer but their spatial heterogeneity has not been extensively explored in this type of cancer. Here, their potential as prognostic biomarkers was evaluated, depending on their combined densities in the tumor center (TC) and the tumor invasive margin (IM). Methods CD8+ and CD163+ cells were quantified by immunohistochemistry of formalin-fixed, paraffin-embedded (FFPE) tumor tissue samples from a cohort totaling 162 patients with histologically-confirmed primary invasive non-metastatic ductal breast cancer diagnosed between 2000 and 2015. Clinical follow-up (median 6.9 years) was available for 97 of these patients. Results Differential densities of CD8+ and CD163+ cells in the combined TC and IM compartments (i.e., high(H)/low(L), respectively for CD8+ cells and the reverse L/H combination for CD163+ cells) were found to have significant prognostic value for survival, and allowed better patient stratification than TNM stage, tumor size, lymph node invasion and histological grade. The combined evaluation of CD8+ and CD163+ cell densities jointly in TC and IM further improves prediction of clinical outcomes based on disease-free and overall survival. Patients having the favorable immune signatures had favorable clinical outcomes despite poor clinicopathological parameters. Conclusions Given the important roles of CD8+ and CD163+ cells in regulating opposing immune circuits, adding an assessment of their differential densities to the prognostic biomarker armamentarium in breast cancer would be valuable. Larger validation studies are necessary to confirm these findings. Trial registrations Study code: IRB-ID 6079/448/10-6-13 Date of approval: 10/06/2013 Retrospective study (2000–2010) First patient prospectively enrolled 14/2/2014

10 June 2014 in Stem Cells and Development
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LMLouisa G. Mahaira
Louisa G. Mahaira
OKOlga Katsara
Olga Katsara
EPEfthimia Pappou
Efthimia Pappou
EIEleni G. Iliopoulou
Eleni G. Iliopoulou
SFSotirios P. Fortis
Sotirios P. Fortis
SPSonia A. Perez
Sonia A. Perez
Mesenchymal stem cells (MSCs) are a population of cells harboring in many tissues with the ability to differentiate toward many different lineages. Unraveling the molecular profile of MSCs is of great importance due to the fact that these cells are very often used in preclinical and clinical studies. We have previously reported the expression of insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) an oncofetal mRNA-binding protein—in different stem cell types such as bone marrow (BM)-MSC and umbilical cord blood (UCB)-hematopoietic stem cells. Here, we demonstrate that MSCs of adipose tissue, BM, and UC origin have a differential pattern of IGF2BP1 and ten-eleven-translocate 1/2 (TET1/2) expression that could correlate with their proliferation potential. Upon IGF2BP1 interference, a significant reduction of cell proliferation is observed, accompanied by reduced expression of c-MYC and GLI1 and increased p21. We also present, for the first time, evidence that IGF2BP1 is epigenetically regulated by TET1 and TET2 demethylases. Specifically, we show that TET1 directly binds to the promoter of IGF2BP1 gene and affects the hydroxymethylation status of its promoter. These results indicate that IGF2BP1 and TET1/2 contribute to the stemness of MSCs, at least regarding their proliferative potential.

23 February 2018 in PLOS Pathogens
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DWDionysios C Watson
Dionysios C Watson
EMEirini Moysi
Eirini Moysi
AVAntonio Valentin
Antonio Valentin
CBCristina Bergamaschi
Cristina Bergamaschi
SDSANTHI DEVASUNDARAM
SANTHI DEVASUNDARAM
GPGeorge N. Pavlakis
George N. Pavlakis
B cell follicles in secondary lymphoid tissues represent an immune privileged sanctuary for AIDS viruses, in part because cytotoxic CD8+ T cells are mostly excluded from entering the follicles that harbor infected T follicular helper (TFH) cells. We studied the effects of native heterodimeric IL-15 (hetIL-15) treatment on uninfected rhesus macaques and on macaques that had spontaneously controlled SHIV infection to low levels of chronic viremia. hetIL-15 increased effector CD8+ T lymphocytes with high granzyme B content in blood, mucosal sites and lymph nodes, including virus-specific MHC-peptide tetramer+ CD8+ cells in LN. Following hetIL-15 treatment, multiplexed quantitative image analysis (histo-cytometry) of LN revealed increased numbers of granzyme B+ T cells in B cell follicles and SHIV RNA was decreased in plasma and in LN. Based on these properties, hetIL-15 shows promise as a potential component in combination immunotherapy regimens to target AIDS virus sanctuaries and reduce long-term viral reservoirs in HIV-1 infected individuals. Trial registration: ClinicalTrials.gov NCT02452268 Heterodimeric interleukin-15 (hetIL-15), the stable native complex of IL-15 and IL-15 Receptor α (IL-15/IL-15Rα), activates and expands cytotoxic T and NK cells. Based on these properties, hetIL-15 is currently being evaluated in clinical trials in advanced cancer. To explore potential utility in AIDS virus infection, we evaluated the effects of hetIL-15 in uninfected rhesus macaque monkeys or monkeys with low levels of chronic viremia after SHIV infection. hetIL-15 treatment increased CD8+ lymphocytes within the B cell follicles of lymph nodes and decreased cell-associated viral RNA in LN as well as plasma viremia. These results suggest hetIL-15 may have beneficial effects in chronic HIV infection by allowing CD8+ T cells to access infected cells within otherwise immune privileged sanctuary sites in B cell follicles of secondary lymphoid tissues.

4 September 2021 in Biomolecules
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Journal Article
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EPEfthimia G. Pavlou
Efthimia G. Pavlou
HGHara T. Georgatzakou
Hara T. Georgatzakou
SFSotirios P. Fortis
Sotirios P. Fortis
KTKonstantina A. Tsante
Konstantina A. Tsante
Andreas G. TsantesAndreas G. Tsantes
Andreas G. Tsantes
Anastasios G. KriebardisAnastasios G. Kriebardis
Anastasios G. Kriebardis
Coagulation abnormalities in renal pathology are associated with a high thrombotic and hemorrhagic risk. This study aims to investigate the hemostatic abnormalities that are related to the interaction between soluble coagulation factors and blood cells, and the effects of hemodialysis (HD) on it, in end stage renal disease (ESRD) patients. Thirty-two ESRD patients under HD treatment and fifteen healthy controls were included in the study. Whole blood samples from the healthy and ESRD subjects were collected before and after the HD session. Evaluation of coagulation included primary and secondary hemostasis screening tests, proteins of coagulation, fibrinolytic and inhibitory system, and ADAMTS-13 activity. Phosphatidylserine (PS) exposure and intracellular reactive oxygen species (iROS) levels were also examined in red blood cells and platelets, in addition to the platelet activation marker CD62P. Platelet function analysis showed pathological values in ESRD patients despite the increased levels of activation markers (PS, CD62P, iROS). Activities of most coagulation, fibrinolytic, and inhibitory system proteins were within the normal range, but HD triggered an increase in half of them. Additionally, the increased baseline levels of ADAMTS-13 inhibitor were further augmented by the dialysis session. Finally, pathological levels of PS and iROS were measured in red blood cells in close correlation with variations in several coagulation factors and platelet characteristics. This study provides evidence for a complex coagulation phenotype in ESRD. Signs of increased bleeding risk coexisted with prothrombotic features of soluble factors and blood cells in a general hyperfibrinolytic state. Hemodialysis seems to augment the prothrombotic potential, while the persisted platelet dysfunction might counteract the increased predisposition to thrombotic events post-dialysis. The interaction of red blood cells with platelets, the thrombus, the endothelium, the soluble components of the coagulation pathways, and the contribution of extracellular vesicles on hemostasis as well as the identification of the unknown origin ADAMTS-13 inhibitor deserve further investigation in uremia.