Figure 15. MDA-MB-231 breast cancer cell lines, which overexpress p16(INK4A) and p21(WAF1/CIP1), undergo autophagy, and show dramatically reduced tumor growth. (A) Autophagy status. MDA-MB-231 cells, which overexpress p16(INK4A) and p21(WAF1/CIP1), undergo increased authophagy, either at baseline (Lamp-1, BNIP3, LC3-I/II) or under conditions of starvation for 12 h with HBSS (Beclin-1 and cathepsin B). (B) Tumor growth. MDA-MB-231 cells, which overexpress p16(INK4A) and p21(WAF1/CIP1), show a near 2-fold reduction in tumor volume.