Rediject d luciferin ultra bioluminescent substrate

Prior to imaging, the mice were i.p. injected with 100 μL of 30 mg/ml RediJect D-Luciferin Ultra bioluminescent substrate (PerkinElmer). Mice were then anesthetized with isoflurane and imaged within 20 minutes for bioluminescence using the in vivo imager. All the bioluminescence data, except for those shown in Supplementary Figures 7d and e, were collected using the IVIS Spectrum In Vivo Imaging System (PerkinElmer), and bioluminescent photon outputs were quantified using the Living Image Software (PerkinElmer). The bioluminescence data shown in Supplementary Figures 7d and e were collected using the Lago X optical imaging system (Spectral Instruments Imaging) and analyzed using Aura software (Spectral Instruments Imaging).

To establish mir-155^LSLtTA lymphoma subcutaneous flank tumors, first enlarged spleens were extracted from 2–3 month-old mir-155^LSLtTA mice with obvious lymphadenopathy (which generally correlated with incidence of splenomegaly). Using a 100 μm pore size cell strainer technique, spleen tissue was dispersed into a single cell suspension in 5% FBS in PBS on ice. Red blood cells were lysed using ammonium chloride lysis buffer (Stem Cell Technologies), and 5 × 10⁶ cells were subcutaneously injected into nude mice. Tumors were generally palpable within 10 days; tumor volume was calculated as (Length x Width²)/2.
For bioluminescent xenograft tumors, KB cells were stably transfected with firefly luciferase and clonally selected via hygromycin B selection; 5 × 10⁶ cells were subcutaneously injected into nude mice to establish tumors. RediJect D-Luciferin Ultra Bioluminescent Substrate (PerkinElmer) was administered via the manufacturer’s protocol for intravital monitoring of tumor bioluminescence using IVIS Spectrum (Caliper). It was pre-established that for all flank tumor studies, animals were excluded if their tumors had not reached a volume of 50–100 cm³ by the time of treatment. Animals were randomized into experimental arms by minimizing the differences in mean tumor size and standard deviation.