Complete digestion of a cell-in-cell structure after chemotherapy

Camptothecin treatment of MCF7 cells induces either a classic senescent phenotype or the formation of cell-in-cell structures (CIC).

After the internalization of a neighboring cell, MCF7 cells develop a digestive vacuole (see arrow in Fig.1). The vacuole undergoes sequential steps of maturation, culminating in the degradation of the internalized cell (Fig. 2).

Fig. 1. Representative time lapse image sequence of MCF7 cells treated with 250 nM camptothecin. The yellow arrows indicate the vacuole inside an individual cell.
Fig. 2. Confocal microscopy of a MCF7 cell treated with 250nM camptothecin after cell ingestion (red: LC3-B; blue: DAPI).