Lymphatic ECFCs were infected with KSHV for 5 days, and treated with siRNA targeting SOX18, or control siRNA (siNeg) transfected for 72h (A-E) or with the indicated concentrations of SM4 inhibitor or the corresponding concentrations of DMSO control for 6 days, replenished at day 3 (E-I). The effect of treatments is shown as quantified; A and G of KSHV genome copies from total DNA, B and H of percent of LANA positive cells on 96-well plate, and C and I of KSHV titers measured from virus release assay on naïve U2OS cells. D. The efficiency of SOX18 silencing shown at a protein level. E. Changes in spindling morphology, GFP (latent) and RFP (lytic) cells shown with the siRNA targeting SOX18 or 25 μM and 50 μM of SM4 and the highest DMSO concentration control. * p < 0.05, ** p < 0.01, *** p < 0.001.