Tumor necrosis factor (TNF) inhibitors (anti-TNFs) represent a cornerstone of the treatment of various immune-mediated inflammatory diseases and are among the most commercially successful therapeutic agents. Knowledge of TNF binding partners is critical for identification of the factors able to affect clinical efficacy of the anti-TNFs. Here, we report that among eighteen representatives of the multifunctional S100 protein family, only S100A11, S100A12 and S100A13 interact with the soluble form of TNF (sTNF) in vitro. The lowest equilibrium dissociation constants (K_d) for the complexes with monomeric sTNF determined using surface plasmon resonance spectroscopy range from 2 nM to 28 nM. The apparent K_d values for the complexes of multimeric sTNF with S100A11/A12 estimated from fluorimetric titrations are 0.1–0.3 µM. S100A12/A13 suppress the cytotoxic activity of sTNF against Huh-7 cells, as evidenced by the MTT assay. Structural modeling indicates that the sTNF-S100 interactions may interfere with the sTNF recognition by the therapeutic anti-TNFs. Bioinformatics analysis reveals dysregulation of TNF and S100A11/A12/A13 in numerous disorders. Overall, we have shown a novel potential regulatory role of the extracellular forms of specific S100 proteins that may affect the efficacy of anti-TNF treatment in various diseases.

The secondary metabolites of the fungus Penicillium thymicola, fumiquinazolines F and G, have antibacterial and antifungal characteristics; however, their potential anti-tumor action against human cancer cells remains unknown. The goal of our study was to determine the biological efficacy of fumiquinazolines F and G on breast and prostate cancer cells. Cancer cell proliferation and migration were monitored in real time using xCELLigence technology and flow cytometry. Alterations in mRNA and protein expression were assessed by RT-qPCR, ELISA, and Western blotting. Our data indicate that fumiquinazolines F and G are more effective in inhibiting breast cancer cell proliferation than prostate cancer cells. Fumiquinazoline F is active against both hormone-dependent epithelial MCF-7 (IC₅₀ 48 μM) and hormone-resistant triple-negative mesenchymal MDA-MB-231 breast cancer cells (IC₅₀ 54.1 μM). The metabolite has low cytotoxicity but slows cell cycle progression. In fumiquinazoline F-treated MDA-MB-231 cells, the levels of proteins implicated in epithelial–mesenchymal transition (EMT) (such as E-cadherin, vimentin, and CD44) fluctuate, resulting in a decrease in cell migratory rate and adhesion to a hyaluronic acid-coated substrate. Thus, fumiquinazolines F and G exhibit anticancer activity by inhibiting EMT, cell proliferation, and migration, hence reverting malignant cells to a less pathogenic phenotype. The compound’s multi-target anticancer profile underscores its potential for further exploration of novel EMT-regulating pathways.

Tumor necrosis factor (TNF) inhibitors (anti-TNFs) represent a cornerstone of the treatment of various immune-mediated inflammatory diseases and are among the most commercially successful therapeutic agents. Knowledge of TNF binding partners is critical for identification of the factors able to affect clinical efficacy of the anti-TNFs. Here we report that among eighteen representatives of the multifunctional S100 protein family only S100A11, S100A12 and S100A13 interact with the soluble form of TNF (sTNF) in vitro. The lowest equilibrium dissociation constants (Kd) for the complexes with monomeric sTNF determined using surface plasmon resonance spectroscopy range from 2 nM to 28 nM. The apparent Kd values for the complexes of multimeric sTNF with S100A11/A12 estimated from fluorimetric titrations are 0.1-0.3 µM. S100A12/A13 suppress the cytotoxic activity of sTNF against Huh-7 cells, as evidenced by the MTT assay. Structural modeling indicates that the sTNF-S100 interactions may interfere with the sTNF recognition by the therapeutic anti-TNFs. Bioinformatic analysis reveals dysregulation of TNF and S100A11/A12/A13 in numerous disorders. Overall, we have shown a novel potential regulatory role of the extracellular forms of specific S100 proteins that may affect efficacy of anti-TNF treatment in various diseases.

Cells attached to a substrate and grown in a two dimensional (2D) or suspension culture cannot accurately replicate intercellular interactions in tissues and organs. Spheroids, being three-dimensional (3D) formations, more accurately reproduce the structure of organs or neoplasms, and compared to 2D cultures, demonstrate increased survival, corresponding morphology, and a hypoxic core, which is observed in native tumors in vivo. Tumor cell spheroids also represent models of the metastatic process. Therefore, spheroids are currently widely used for testing new anticancer drugs. However, obtaining and using 3D cultures can be associated with a number of difficulties, such as the need for expensive reagents and equipment; a low rate of formation of spheroids of the required size; and occurrence of long-term changes in cell metabolism, which depend on the methods used to create spheroids. We have found that incubation of tumor and normal cells in the presence of polymers of 2,5-dihydroxybenzoic acid (2,5-DHBA), which are nontoxic to cells, can induce the formation of 3D structures. Based on this, a new method for the rapid production of 3D cultures was developed. This approach does not require the use of additional equipment or expensive reagents and does not have a long-term effect on cell homeostasis. The spheroids obtained by this method represent models of three-dimensional structures and can be used for biological studies of intercellular interactions and screening of pharmaceutical products.