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

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 mm(3)) 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 CaHPO(4) (monetite) and β-Ca(2)P(2)O(7) (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 Ca(2+) 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.