(A) Cells from a primary tumor were harvested and passaged in vivo in syngeneic C57BL/6×129F1 mice. Myc/p53ER^TAM cells were injected subcutaneously into the flanks of mice. Once tumors had reached more than 1,700 mm³, mice were matched for tumor size and treated with 50 mg/kg cyclophosphamide i.p. once followed by either daily PBS i.p. (top panel) or 60 mg/kg/d CQ i.p. (bottom panel) for a total of 13 days. Daily tumor volumes are shown for individual mice. CY, cyclophosphamide. (B) Time to tumor recurrence for cyclophosphamide/PBS- and cyclophosphamide/CQ-treated mice (mean ± SD). *P = 0.003. (C) GFP-LC3 fluorescence. Green, GFP-LC3; blue, DAPI. A bulk population of primary Myc/p53ER^TAM lymphoma cells with stable expression of the GFP-LC3 fusion protein was treated with 50 μM MNNG with or without 10 μM CQ. Cell culture medium was changed daily. Cells were fixed and imaged using fluorescence microscopy at 24 and 48 hours. Representative images of cells at 48 hours are presented. (D) Quantification of the percentage of cells with more than 4 GFP-LC3 puncta per cell (punctate) compared with those with less than 4 GFP-LC3 puncta per cell (diffuse) at 24 and 48 hours after treatment. (E) MNNG with and without CQ treatment in HC and shATG5 cells. On day 0, 2 × 10⁶ cells/ml of HC, h2, and h7 lymphoma cells were plated and treated with 20 μM MNNG (red) or 20 μM MNNG plus 5 μM CQ (blue). Viable cell number as determined by trypan blue exclusion was counted after 24 hours and 48 hours of treatment. Reported values are means ± SD of triplicate samples of a representative experiment.