Cellular passages modulate pre-osteoblast responses to bisphosphonate in high-passage cell models.

OBJECTIVE This study examined the effects of cell passages, drug treatment, or interaction between cell passage and drug treatment on pre-osteoblast growth and activities.

DESIGN Pre-osteoblasts, MC3T3-E1, were subcultured until reaching high passages (passage 42; P42) and late passages (passage 62; P62). Cells were treated with oral bisphosphonate (BP), alendronate (ALN), at concentrations 1 and 5 μM. Cells were evaluated and compared for cell survival, migration, adhesion, actin cytoskeleton, cell spreading, and gene expressions.

RESULTS Two-way ANOVA showed that cell migration, cytoskeleton, nuclear condensation, and Intβ1 gene expression were impacted by the interaction between cell passage and ALN, while cell growth, death, adhesion, and spreading were affected by either cell passage or ALN. Cell growth was inhibited by cell passage and ALN. ALN at 5 μM (A5) increased cell death in P42. Cell adhesion was reduced in P62 compared to P42 in A1 condition. Higher cell passage and ALN promoted detachment under mechanical stress. Cell spreading was also disrupted by ALN. Adhesion-related gene expressions such as Intβ1 and FAK were downregulated by cell passage in A5 treatment.

CONCLUSION These findings demonstrated differential cellular responses to BPs based on cell passage and interaction between cell passage and ALN. High and late passage cells exhibited distinct sensitivities and behaviors. This underscores the importance of using higher-passage cell models to better mimic aged osteoblasts in vitro when evaluating preclinical studies.