Figure 4

5C6 induces senescence in BRCA2-deficient DLD1 cells.

(A): 5C6 does not appear to induce apoptosis or necrosis of BRCA2- DLD1 cells. Cells were treated with control media or media containing 10 μM 5C6 and cell membrane integrity was then examined by visualization of PI uptake. No difference in PI uptake was observed between the cells treated with control or 5C6, suggesting that apoptosis or necrosis are not the primary mechanisms by which 5C6 is toxic to the BRCA2- cells. (B), (C) and (D): 5C6 induces senescence in the BRCA2- DLD1 cells. Cells were treated with control media or media containing 6.6 μM 5C6 and were then stained for β-gal as a marker of senescence. Representative images are shown in B and the percentage of β-gal-positive cells was quantified in C. *p = 0.009 (n = 2). The impact of 5C6 on the percentage of β-gal-positive cells was dose dependent (D).