Quinalizarin inhibits adipogenesis through down-regulation of transcription factors and microRNA modulation

Protein kinase CK2 is induced early in adipogenesis whereas later on, this kinase seems to be dispensable. Here, we have analysed how CK2 might be involved in early steps of differentiation of 3T3-L1 cells. 3T3-L1 cells were differentiated to adipocytes in the absence or presence of quinalizarin. The expression and localization of important transcription factors was analysed by Western blot and immunofluorescence. DNA binding capacity and transactivation was analysed with pull-down assays and with luciferase reporter experiments, respectively. mRNA was detected with qRT-PCR, miRNAs with Northern hybridization and qRT-PCR. We show that clonal expansion was considerably repressed upon inhibition of CK2 with quinalizarin. Moreover, to prevent adipogenesis CK2 inhibition had to take place before day 4 of differentiation. Neither the expression at the protein or at the RNA level nor the subcellular localization of the transcription factors C/EBPβ and C/EBPδ was affected by CK2 inhibition. There was, however, a drastic reduction in the mRNA and protein levels of C/EBPα and PPARγ2. Upon inhibition of CK2, we found a significant up-regulation of the level of the microRNAs miR-27a and miR-27b, which are known to target PPARγ mRNA. Time course experiments revealed that CK2 seems to be required at early time points after the induction of differentiation. One important target of CK2 was identified as PPARγ, which is down-regulated after inhibition of CK2. This is the first report about i) cellular targets of CK2 during adipogenesis and ii) a role of CK2 in microRNA regulation. [Display omitted] •Inhibition of CK2 by quinalizarin prevents adipogenic differentiation of 3T3-L1.•Inhibition of CK2 is effective within the early phase of differentiation.•Inhibition of CK2 compromises the clonal expansion of 3T3-L1 cells.•mRNA and protein of PPARγ and C/EBPα are down-regulated in CK2-inhibited cells.•The lack of these key proteins is due to an up-regulation of specific miRNAs.