VEGF expression is regulated by PKM2 in KSHV-infected cells. a Immunofluorescent staining of PKM2 and HIF1α in IN-KSHV and KSHV cells. b Real-time PCR analysis of HIF downstream genes (BNIP3, GLUT1, HK2, LDHA, VEGF) in KSHV cells expressing (control) scrambled siRNA or PKM2 siRNA. c, d HUVEC (c) or KSHV (d) cells were transfected with increasing doses of PKM1, PKM2, and PKM2 K270M expression vector (pcDNA3.1-V5-His) (c) or increasing doses of PKM2 siRNA (d), along with pGL-VEGF/K and pCEFL Renilla luciferase. Luciferase activity and Renilla activity (for normalization) were determined as described in “Materials and methods” section. e Levels of VEGF protein expression and VEGF secretion of HUVEC and KSHV expressing no siRNA (No si), scrambled siRNA (Scr si) or PKM2 siRNA (PKM2 si)