Fig. 6.

E2F1, c-Myc expression and cell viability are mediated via PI3Kδ in EBNA1 transgenic mouse tumour cells. a Primary lymphoma cells derived from mice were cultured (in triplicate) with 10–100 µM CAL-101 or DMSO, or no additive (control) for 6 days. Rapid cell death correlates with increasing concentrations of CAL-101. b Cells from three different explanted primary EBNA1-positive transgenic lymphomas were each cultured in triplicate for 4 days with 10 µM CAL-101 added (in 0.01% DMSO) or 0.01% DMSO. The ratio of CAL-101 and DMSO-treated cell counts against untreated cell counts is graphed. c, d Western blots showing a time course of the expression of E2F1 and c-Myc in non-transgenic cells (WT) and using transgenic cells from two different primary tumours (ID:26.3404 [C] and 26.3388 [D]) (see also Supplementary Fig. 9a). Explanted EµEBNA1 transgenic tumour cells were cultured for up to 4 days, with no treatment (NT), or with vehicle (DMSO) or with daily treatment of 10 µM CAL-101, as indicated. E2F1 and c-Myc expression in the EBNA1 transgenic lymphoma cells are markedly reduced by CAL-101 treatment. e Cell growth was measured for 7 days in two mouse B cell lymphoma cell lines LMP1 positive (ID: 39.415) and the bi-transgenic LMP1 and EBNA1 positive (ID: 3959.48). Cells were cultured with daily addition of CAL-101 to 50 µM, or with vehicle (DMSO) and viable cells counted. f Western blots showing the expression of E2F1 in two Burkitt’s lymphoma cell lines carrying c-myc gene translocation. Raji is EBV positive and BL41 is EBV negative. Both were treated with CAL-101 (10 µM) for indicated time. g Western blots showing c-Myc expression following treatment with CAL-101 (10 µM) in Raji and the lymphoblastoid cell line B95.8 (no c-myc gene translocation). Western blots represent n ≥ 3; Actin was used as a loading control. The values in a, b and e represent the mean data from three independent experiments with s.d