The inhibitory action of HMP-S7 on leukemic cells. (a) Four leukemic cell lines, namely Jurkat, Raji, RS4;11, and Sup-B15 cells, were treated with HMP-S7 at various concentrations (0–400 µM) for 24 h, and the % cell death (mean ± SD) was determined using trypan blue exclusion assay; (b) effects of HMP-S7 (100, 200, and 400 µM) and the positive control BMP-S6 (200 µM) on the colony forming ability of Jurkat cells (three independent experiments; N1–N3). After the treatment with the test peptide for 24 h, cell suspensions were allowed to form colonies in soft agar for 20 days. The colonies in the soft agar were stained with crystal violet and counted. ** p < 0.01 compared to untreated condition (n = 3 biological replicates).