Bovine milk osteopontin induces cytokine release in buccal carcinoma cells.

OBJECTIVES: This exploratory study investigated the effects of bovine milk osteopontin on an experimentally induced inflammatory state in a monolayer of buccal carcinoma cells (TR146) with the aim of exploring possible immunomodulatory effects. DESIGN: TR146 cells were used as an experimental model for buccal epithelial cells. Cells were stimulated using the physiological (6 μM) and highest tolerated (600 μM) concentration of osteopontin based on cell toxicity and viability assays. A milk protein control (α-lactalbumin), a negative (cell growth media) and a positive (cell growth media plus 100 ng/mL TNF-α) control were included. Effects of both proteins were assessed with/without the presence of 100 ng/mL TNF-α by examining the levels of 45 different cytokines using proximity extension assay. RESULTS: Seventeen cytokine levels were significantly changed (p ≤ .044). Compared with the negative control, stimulation with 600 μM osteopontin induced changes in levels of six cytokines (p ≤ .018), while 600 μM α-lactalbumin induced increases in three (p ≤ .008). Compared with the positive control, 600 μM osteopontin alongside TNF-α induced increases in three cytokines (p ≤ .049), while 600 μM α-lactalbumin alongside TNF-α induced increases in two (p ≤ .026). Osteopontin stimulation increased the levels of cytokines involved in leukocyte recruitment, angiogenesis and tissue remodelling. CONCLUSION: Bovine milk osteopontin at 600 μM demonstrated pro-inflammatory effects and may be relevant for tissue healing promotion.