Hara Polioudaki1, Amanda Chantziou1, Konstantina Kalyvianaki2, Panagiotis Malamos2, George Notas2, Dimitris Mavroudis3,4, Marilena Kampa2, Elias Castanas2, Panayiotis A Theodoropoulos5. 1. Department of Biochemistry, School of Medicine, University of Crete, Voutes, 71013, Heraklion, Crete, Greece. 2. Laboratory of Experimental Endocrinology, School of Medicine, University of Crete, Heraklion, Crete, Greece. 3. Department of Medical Oncology, University General Hospital of Heraklion, Heraklion, Crete, Greece. 4. Laboratory of Translational Oncology, School of Medicine, University of Crete, Heraklion, Crete, Greece. 5. Department of Biochemistry, School of Medicine, University of Crete, Voutes, 71013, Heraklion, Crete, Greece. takis@uoc.gr.
Abstract
BACKGROUND: The levels of expression and membrane localization of programmed cell death ligand 1 (PD-L1), an immune checkpoint type I transmembrane glycoprotein, are related to the clinical response of anti-PD-L1/PD-1 therapy. Although the biologically relevant localization of PD-L1 is on the plasma membrane of cancer cells, it has also been reported to be in the cytoplasm and sometimes in the nucleus. Furthermore, it has been claimed that chemotherapeutics can modify PD-L1 expression and/or its nuclear localization. RESULTS: Data from our group suggest that the nuclear localization of PD-L1, and other plasma membrane proteins as well, could be an artifact resulting from inadequate experimental conditions during immunocytochemical studies. Mild detergent and rigorous fixation conditions should be used in order to preserve the membrane localization and to prevent an erroneous translocation of PD-L1 and other non-interconnected membrane proteins, such as CD24, into other cellular compartments including the nucleus, of untreated and chemotherapeutically treated breast cancer cells. CONCLUSION: We propose that well-specified and rigorously followed protocols should be applied to immunocytochemical diagnostic techniques, especially to those related to individualized diagnosis and treatment.
BACKGROUND: The levels of expression and membrane localization of programmed cell death ligand 1 (PD-L1), an immune checkpoint type I transmembrane glycoprotein, are related to the clinical response of anti-PD-L1/PD-1 therapy. Although the biologically relevant localization of PD-L1 is on the plasma membrane of cancer cells, it has also been reported to be in the cytoplasm and sometimes in the nucleus. Furthermore, it has been claimed that chemotherapeutics can modify PD-L1 expression and/or its nuclear localization. RESULTS: Data from our group suggest that the nuclear localization of PD-L1, and other plasma membrane proteins as well, could be an artifact resulting from inadequate experimental conditions during immunocytochemical studies. Mild detergent and rigorous fixation conditions should be used in order to preserve the membrane localization and to prevent an erroneous translocation of PD-L1 and other non-interconnected membrane proteins, such as CD24, into other cellular compartments including the nucleus, of untreated and chemotherapeutically treated breast cancer cells. CONCLUSION: We propose that well-specified and rigorously followed protocols should be applied to immunocytochemical diagnostic techniques, especially to those related to individualized diagnosis and treatment.
Entities:
Keywords:
Breast cancer; Doxorubicin; Nuclear localization; PD-L1; Plasma membrane
Authors: Niclas C Blessin; Patrick Spriestersbach; Wenchao Li; Tim Mandelkow; David Dum; Ronald Simon; Claudia Hube-Magg; Florian Lutz; Florian Viehweger; Maximillian Lennartz; Christoph Fraune; Vera Nickelsen; Wilfried Fehrle; Cosima Göbel; Sören Weidemann; Till Clauditz; Patrick Lebok; Katharina Möller; Stefan Steurer; Jacob R Izbicki; Guido Sauter; Sarah Minner; Frank Jacobsen; Andreas M Luebke; Franziska Büscheck; Doris Höflmayer; Waldemar Wilczak; Eike Burandt; Andrea Hinsch Journal: Cell Oncol (Dordr) Date: 2020-03-05 Impact factor: 6.730