Mesenchymal stromal cells (MSCs) influence tumor biology and immunology by releasing cytokines, chemokines and growth factors. Currently, cisplatin is an integral part of drug-based tumor therapy, for example, in head and neck squamous cell carcinoma (HNSCC). Cisplatin treatment induces apoptosis as a primary mechanism of action; however, additional immunomodulatory effects of cisplatin are gaining interest. The aim of this study is to evaluate the possible immunomodulatory effects of cisplatin in human MSCs (hMSCs). The MSCs, obtained from human bone marrow, were characterized by analyzing plastic adherence, typical surface features, and ability to differentiate. Toxicity analysis of cisplatin’s effects on primary MSCs, including the determination of a subtoxic concentration, was performed using the MTT assay. Enzyme-linked immunosorbent assays (ELISA) and a quantitative real-time polymerase chain reaction (qRT-PCR) were used to identify potentially immunomodulatory factors. Additionally, a scratch assay was performed to evaluate cell migration. First, subtoxic cisplatin concentrations were determined. A significantly reduced protein expression of indoleamine 2,3-dioxygenase 1 (IDO1) in MSCs under the influence of subtoxic cisplatin concentrations was demonstrated. Similarly, IL-6 protein expression was qualitatively reduced at subtoxic concentrations, although without statistical significance. At the mRNA level, qRT-PCR showed a non-significant, cisplatin concentration-dependent reduction in the expression of both IL-6 and IDO1. The scratch assay showed no statistically significant influence on migration after cisplatin treatment. In MSCs, there is tendency to a decrease in IL-6 and IDO1 at both protein and mRNA level after cisplatin exposure. These effects are congruent with each other and dose-dependent. This indicates that cisplatin not only acts via the known cytotoxic effect, but may induce a reduction in tumor-supporting proteins, like IL-6 and IDO1, by MSCs in the tumor microenvironment at subtoxic concentrations. Traditional cytostatic compounds, which can favorably modulate the immune system in the tumor microenvironment, may open new avenues to explore treatment strategies specifically targeting immunomodulation. Overall, the results indicate beneficial immunomodulation by cisplatin.

α‑solanine is a glycoalkaloid that is commonly found in nightshades (Solanum) and has a toxic effect on the human organism. Among other things, it is already known to inhibit tumor cell proliferation and induce apoptosis in tumor cell lines. Due to its potential as a tumor therapeutic, the current study investigated the effect of α‑solanine on head and neck squamous cell carcinoma (HNSCC). In addition, genotoxic and antiangiogenic effects on human umbilical vein endothelial cells (HUVECs) were evaluated at subtoxic α‑solanine concentrations. Cytotoxicity and apoptosis rates were measured in two human HNSCC cell lines (FaDu pharynx carcinoma cells and CAL‑33 tongue carcinoma cells), as well as in HUVECs. MTT and Annexin V analyses were performed 24 h after α‑solanine treatment at increasing doses up to 30 µM to determine cytotoxic concentrations. Furthermore, genotoxicity at subtoxic concentrations of 1, 2, 4 and 6 µM in HUVECs was analyzed using single‑cell gel electrophoresis (comet assay). The antiangiogenic effect on HUVECs was evaluated in the capillary tube formation assay. The MTT assay indicated an induction of concentration‑dependent viability loss in FaDu and CAL‑33 cancer cell lines, whereas the Annexin V test revealed α‑solanine‑induced cell death predominantly independent from apoptosis. In HUVECs, the cytotoxic effect occurred at lower concentrations. No genotoxicity or inhibition of angiogenesis were detected at subtoxic doses in HUVECs. In summary, α‑solanine had a cytotoxic effect on both malignant and non‑malignant cells, but this was only observed at higher concentrations in malignant cells. In contrast to existing data in the literature, tumor cell apoptosis was less evident than necrosis. The lack of genotoxicity and antiangiogenic effects in the subtoxic range in benign cells are promising, as this is favorable for potential therapeutic applications. In conclusion, however, the cytotoxicity in non‑malignant cells remains a severe hindrance for the application of α‑solanine as a therapeutic tumor agent in humans.

Background/Aim: This study aimed to assess the impact of hypoxia on epithelial-mesenchymal transition (EMT) in head and neck squamous cell carcinoma (HNSCC), focusing on the involvement of transcription factors hypoxia inducible factor 1 (HIF-1α) and Jumonji Domain-Containing Protein 1A (JMJD1A). Materials and Methods: FaDu and Cal33 cell lines were subjected to hypoxic and normoxic conditions. Cell proliferation was quantified electronically, while PCR and western blot analyses were used to measure mRNA and protein levels of HIF-1α, JMJD1A, and EMT markers. EMT was further characterized through immunofluorescence, migration, and invasion assays. Results: Hypoxic conditions significantly reduced cell proliferation after 48 hours in both cell lines. HIF-1α mRNA levels increased initially during short-term hypoxia but declined thereafter, while JMJD1A mRNA levels showed a sustained increase with prolonged hypoxia. Western blot analysis revealed contrasting trends in protein levels. EMT marker expression varied markedly over time at both the mRNA and protein levels, suggesting EMT induction in hypoxia within 24 hours. Immunofluorescence, migration, and invasion assays supported these findings. Conclusion: The study provides evidence of hypoxia-induced EMT in HNSCC, although conflicting results suggest a complex interplay among molecular regulators involved in this process.

Mesenchymal stromal cells (MSCs) are multipotent and play an important role in regenerative processes such as wound healing. Data on possible changes and functional restrictions of MSCs due to cisplatin chemotherapy, for example, in the treatment of head and neck cancer, diverge. The aim of this study was to evaluate the influence of cisplatin on MSCs with regard to their defining characteristics and their ability to differentiate and to migrate. MSCs from four human donors (a 59-year-old man, a 63-year-old woman, a 70-year-old man, and a 61-year-old man) were cultured in vitro with and without cisplatin for 24 h, and toxic and subcytotoxic concentrations were determined using an MTT. We then examined the surface phenotype markers (flow cytometry), migration (scratch assay), histological differentiation markers (adipo-, chondro-, osteogenic), and the expression of selected line-associated genes in real-time quantitative PCR (RT-qPCR) (LEP, SOX9, RUNX2). These characteristics were evaluated after treatment with different subcytotoxic, clinically relevant doses of cisplatin. Flow cytometry confirmed the presence of MSCs-characteristic surface markers, which remained stable under treatment with subcytotoxic doses of cisplatin. Cisplatin exposure reduced the mRNA abundance of leptin (a marker for adipogenic differentiation) but increased SOX9 mRNA abundance (chondrogenic differentiation). RUNX (osteogenic differentiation) did not change post cisplatin exposure. Histological analysis showed no difference with regard to osteogenic, chondrogenic, and adipogenic differentiation at doses up to 10 μM cisplatin. Cell migration was not restricted by cisplatin exposure under the conditions used here. The characteristics of MSCs were not different to controls post cisplatin exposure. mRNA analysis suggested induced changes by cisplatin, although this effect was not histologically detectable even at high doses. Based on the single-molecule markers used here, indications for an inhibitory effect of cisplatin on adipogenic differentiation and a rather enhancing effect on chondrogenic and osteogenic differentiation may be hypothesized. The process observed here could further aggravate the already serious problem of malnutrition in head and neck cancer patients, for example. Taken together though, our study confirms overall MSCs tolerance towards cisplatin.