IL-21 has potent antiproliferative and proapoptotic effects on DLBCL cell lines. (A) Proliferative responses of DLBCL cell lines and an MCL cell line (UPN-1) after treatment with IL-21. After treatment for specified time period with IL-21, cells were pulsed for another 4 hours with 3H-thymidine and were harvested for scintillation counting. Results are shown as the means of 3H-thymidine incorporation (± SD) and are representative of 3 independent experiments. Counts of treated cells are given relative to counts of untreated cells, which were set arbitrarily at 100% for each cell line. (B-C) Cells were stimulated with IL-21 at indicated doses for 72 hours and cell viability was assayed by YO-PRO/PI staining. Cells were considered “live” if negative for both YO-PRO and PI staining. Data in panel B demonstrate dose response in the RC-K8 and OCI-LY-3 cells that is representative of 3 independent experiments. Data in panel C represent means ± SE from 3 independent experiments. (D) Cells were treated with IL-21 (100 ng/mL) and/or doxorubicin (100 ng/mL) for 48 hours and cell viability was assayed by YO-PRO/PI staining. Data in panel D represent means ± SE from 3 independent experiments.
