Fig. 1.

Antiproliferative effects of monoamines and related compounds against human malignant B cell lines and proliferating normal lymphocytes. Cells at 5 × 10⁴ per milliliter (unless indicated) were incubated (for 24 h unless indicated), and proliferation was assessed by [³H]thymidine incorporation over the last 4 h. Data are presented as cpm (percentage of control) with mean ± SD from three separate experiments. (a) Effect of monoamines against L3055 BL cells at 10⁵ per milliliter (♦), 5 × 10⁴ per milliliter (□), or 2.5 × 10⁴ per milliliter (○). EC₅₀ values are indicated for cells at 2.5 × 10⁴ per milliliter. (b) Effects of DA (□) l-DOPA (♦), and apomorphine (○) against L3055 cells with EC₅₀ values. (c) Effect of 5 μM (open bars), 10 μM (hatched bars), or 20 μM (shaded bars) DA on proliferation of malignant B cell lines. (d) As for c, but against LCL cells at 2.5 × 10⁴ per milliliter. (e) Effect of DA on normal proliferating lymphocytes (measured on day 3). PBMC were stimulated with phytohemagglutinin (10 μg/ml; ▴) or phorbol 12-myristate 13-acetate (2 ng/ml) plus ionomycin (1 μg/ml; □). Tonsillar B cells were stimulated with phorbol 12-myristate 13-acetate plus ionomycin (□) or soluble CD40L (1 μg/ml; ▴). (f) Effect of overexpressing Bcl-2 in L3055 cells. Apo, apomorphine; ALL, acute lymphocytic leukemia; PLL, prolymphocytic leukemia; MCL, mantle cell lymphoma; PMBL, primary mediastinal B cell lymphoma; DLBCL, diffuse large B cell lymphoma; MM, multiple myeloma.