Figure 2. Analysis of apoptotic state in 3D lymphoma spheroids compared to their 2D cultures.

(A) Flow cytometric analysis demonstrates increased resistance to apoptosis of EL4 and A20 cells in response to treatment with 1 μM doxorubicin (Annexin V positive: apoptotic cells; PI positive: dead cells) in 3D spheroids compared to 2D culture. Apoptosis ratios were calculated from three independent experiments for both cell lines. (B) Western blot analysis of EL4 cells for the expression of apoptosis-regulating proteins in 2D and 3D cultures. Antiapoptotic Bcl-2 and Bcl-xL were upregulated, and proapoptotic Bax was downregulated in 3D cultures than in 2D cultures. Bar graphs depict densitometry quantitation of Bcl-2, Bcl-xL, and Bax protein expression normalized to β-actin. Data represent the means ± SD of three independent experiments. ^*P < 0.05 and ^**P < 0.01 versus the control.