Calcium Phosphate Coating Prepared by Microarc Oxidation Affects hTERT Expression, Molecular Presentation, and Cytokine Secretion in Tumor-Derived Jurkat T Cells

Larisa S Litvinova; Olga G Khaziakhmatova; Valeria V Shupletsova; Kristina A Yurova; Vladimir V Malashchenko; Egor O Shunkin; Pavel A Ivanov; Ekaterina G Komarova; Valentina V Chebodaeva; Ekaterina D Porokhova; Elena A Gereng; Igor A Khlusov

doi:10.3390/ma13194307

Calcium Phosphate Coating Prepared by Microarc Oxidation Affects hTERT Expression, Molecular Presentation, and Cytokine Secretion in Tumor-Derived Jurkat T Cells

Materials (Basel). 2020 Sep 27;13(19):4307. doi: 10.3390/ma13194307.

Affiliations

¹ Center for Immunology and Cell Biotechnology, Immanuel Kant Baltic Federal University, 236029 Kaliningrad, Russia.
² Laboratory of Physics of Nanostructured Biocomposites, Institute of Strength Physics and Materials Science SB RAS, 634055 Tomsk, Russia.
³ Department of Morphology and General Pathology, Siberian State Medical University, 634050 Tomsk, Russia.
⁴ Research School of Chemistry and Applied Biomedical Sciences, National Research Tomsk Polytechnic University, 634050 Tomsk, Russia.

Abstract

Calcium phosphate (CaP) materials are among the best bone graft substitutes, but their use in the repair of damaged bone in tumor patients is still unclear. The human Jurkat T lymphoblast leukemia-derived cell line (Jurkat T cells) was exposed in vitro to a titanium (Ti) substrate (10 × 10 × 1 mm³) with a bilateral rough (average roughness index (R_a) = 2-5 μm) CaP coating applied via the microarc oxidation (MAO) technique, and the morphofunctional response of the cells was studied. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray spectroscope (EDX) analyses showed voltage-dependent (150-300 V) growth of structural (R_a index, mass, and thickness) and morphological surface and volume elements, a low Ca/P_aT ratio (0.3-0.6), and the appearance of crystalline phases of CaHPO₄ (monetite) and β-Ca₂P₂O₇ (calcium pyrophosphate). Cell and molecular reactions in 2-day and 14-day cultures differed strongly and correlated with the Ra values. There was significant upregulation of hTERT expression (1.7-fold), IL-17 secretion, the presentation of the activation antigens CD25 (by 2.7%) and CD95 (by 5.15%) on CD4⁺ cells, and 1.5-2-fold increased cell apoptosis and necrosis after two days of culture. Hyperactivation-dependent death of CD4⁺ cells triggered by the surface roughness of the CaP coating was proposed. Conversely, a 3.2-fold downregulation in hTERT expression increased the percentages of CD4⁺ cells and their CD95⁺ subset (by 15.5% and 22.9%, respectively) and inhibited the secretion of 17 of 27 test cytokines/chemokines without a reduction in Jurkat T cell survival after 14 days of coculture. Thereafter, cell hypoergy and the selection of an hTERT-independent viable CD4⁺ subset of tumor cells were proposed. The possible role of negative zeta potentials and Ca²⁺ as effectors of CaP roughness was discussed. The continuous (2-14 days) 1.5-6-fold reductions in the secretion of vascular endothelial growth factor (VEGF) by tumor cells correlated with the R_a values of microarc CaP-coated Ti substrates seems to limit surgical stress-induced metastasis of lymphoid malignancies.

Keywords: CaP roughness; cell behavior in vitro; correlations; surface electrostatic and electrokinetic potentials; titanium substrate.

Grants and funding

16-15-10031/Russian Science Foundation