Figure 2.
a) Metformin induces senescence-associated heterochromatic nuclear staining. 2 × 104 cells were plated on chamber slides and after 24 hours, incubated in the presence or absence of 1 mM metformin for 7 days and stained in DAPI nuclear stain (blue). Punctate nuclear staining is indicative of stress induced cell senescence. B) Metformin causes a senescent phenotype in breast cancer cells. 105 cells were plated each well of a 6 plate. After 24 hours, cells were incubated in presence or absence (control) of 1 mM metformin. Cultures were released from metformin after 2 days and cultured for an additional 5 days, after which they were fixed in formaldehyde and stained with crystal violet. Cell hypertrophy is indicated by arrows.