To investigate the effect of EZH2 on the transcriptional activation of SREBP2 targets, we treated Oci-Ly8 and SUDHL4 for 6 days with EZH2 inhibitor (GSK343) either in normal medium supplemented with FCS, or in lipoprotein-deprived serum (LPDS) to mimic a lipid starvation.
Cholesterol biosynthesis and uptake are under the transcriptional control of the transcription factor sterol regulatory element binding protein 2 (SREBP2), which activation is controlled by the endoplasmic reticulum (ER) membrane cholesterol content. Given the impaired LDL uptake observed upon EZH2 inhibition in GCB-DLBCL cell lines, we reasoned that cells would require enhanced activation of the SREBP2 pathway to promote cholesterol biosynthesis and fulfill their cholesterol requirements. To investigate this possibility, we performed a transcriptomic analysis on the EZH2i-insensitive GCB-DLBCL cell lines and compared the transcriptional landscape between cell lines cultured in complete medium (i.e. IMDM containing 10% FCS) or in medium containing lipoprotein-deprived serum (LPDS) in the presence or absence of EZH2 inhibitor (GSK343).