PKCβII gene transcription and protein kinase activity in CLL cells decrease after 24-hour culture. (A) Quantitative RT-PCR analysis of PKCβ mRNA levels in CLL cells showing the effect of in vitro culture in the presence and absence of 100nM LY379196 on PKCβ expression. A 24-hour incubation of CLL cells resulted in a significant drop in PKCβ mRNA levels (P = .002, n = 9). Results are reported as a percentage of PKCβ mRNA levels in CLL cells at T = 0. (B) Western blot analysis of Btk in anti–pS¹⁸⁰-Btk immunoprecipitates from CLL cells (top panel), and in whole-cell lysates (bottom panel). Where CLL cells were incubated with LY379196, a concentration of 100nM was used. (C) Quantitative RT-PCR analysis of PKCβ mRNA levels in CLL cells exposed to 200nM mithramycin for 24 hours. Treatment of CLL cells with mithramycin resulted in a significant reduction in PKCβ mRNA levels compared with untreated (UT) cells (P = .013, n = 5). PKCβ mRNA amounts are reported in femtograms (fg) of PKCβ plasmid DNA equivalents.