Abstract
Anoikis is a specific type of apoptosis caused by the detachment of anchorage-dependent cells from their supportive matrix. Aggregation of suspended cells is believed to suppress anoikis. Here, we describe the effects of cellular aggregation on anoikis in MDCK cells. Suspension cultures of MDCK cells grown under conditions known to induce extensive cellular aggregation were less able to re-attach to culture dishes, exhibited higher caspase-8 activity, and contained more sub-G1 cells than suspension cultures with less cellular aggregation. When suspension cultures of MDCK cells were separated into aggregated cells and single cells, the aggregated cells had low caspase-8 activity regardless of suspension conditions, whereas single cells had higher caspase-8 activity that increased with increasing degree of aggregation. These results suggest that cell-cell interactions in cellular aggregates of suspended MDCK cells facilitate anoikis, causing more apoptosis in individual cells than when these cell-cell interactions are absent.
