15d-PGJ₂inhibits cell growth and induces apoptosis in HS-Sultan cells. (A-B) HS-Sultan cells (3 × 10⁵ cells/mL) were treated with 15d-PGJ₂ (10 μM, ▪), PGF_2α (10 μM, ⋄), or control diluent (×) for the indicated time. The number of viable (A) and dead (B) cells was determined at 24 (□), 48 (▦), and 72 hours (▪) after treatment. The results are representative of 3 independent experiments. (C) HS-Sultan cells (5 × 10⁵ cells/mL) were treated with 15d-PGJ₂ (10 μM). Cell cycle profile was evaluated at 0 (Control), 24, 48, or 72 hours after treatment by PI staining using flow cytometry. The percentage of sub-G₀/G₁ cells is indicated on each panel. (D) HS-Sultan cells (5 × 10⁵ cells/mL) were treated with 15d-PGJ₂ (10 μM). Apoptosis was evaluated at 0 (control), 4, 8, and 24 hours after treatment by annexin V-PI staining using flow cytometry. The percentage of annexin V⁺-PI^- cells is indicated on each panel. Early externalization of phosphatidylserine confirmed that 15d-PGJ₂ induces apoptosis in HS-Sultan cells.