Haopeng Yang

OBJECTIVE: Resistin may be associated with obesity and cardiovascular diseases. However, it is unknown whether resistin directly contributes to angiogenesis. In the present study, we evaluated the effects of resistin on angiogenic potential, including endothelial cell proliferation, migration, and capillary-like tube formation. METHODS: Human coronary artery endothelial cells (HCAECs) were treated with resistin. Cell proliferation was evaluated by [3H]thymidine incorporation and MTS assays. Cell migration was assessed by a modified Boyden chamber assay. Capillary-like tube formation was studied with a Matrigel model. Several gene expression levels were determined by real-time PCR. Activation of mitogen-activated protein kinases (MAPKs) was determined by Bio-Plex luminex analyzer. Basic fibroblast growth factor (bFGF) was used as a control. Human umbilical vein endothelial cells (HUVECs) and human lung microvascular endothelial cells (HMVEC-L) were also included. RESULTS: Resistin induced both endothelial proliferation and migration in a dose- and time-dependent manner with the maximal effect at 40 ng/ml. Both resistin-induced cell proliferation and migration could be effectively blocked by a resistin-neutralization antibody. In addition, resistin promoted capillary-like tube formation of HCAECs on Matrigel. Resistin also significantly upregulated the mRNA expression of vascular endothelial growth factor receptors (VEGFR-1 and VEGFR-2) and matrix metalloproteinases (MMP-1 and MMP-2) at both mRNA and protein levels. Furthermore, transient phosphorylation of ERK1/2 and p38 was observed after the addition of resistin to HCAECs. The resistin-induced cell proliferation and migration were both completely blocked by specific ERK1/2 and p38 inhibitors. CONCLUSIONS: Resistin induces human endothelial cell proliferation and migration, promotes capillary-like tube formation, upregulates the expression of VEGFRs and MMPs, and activates ERK1/2 and p38 pathways. Thus, resistin may play an important role in angiogenesis-associated vascular disorders.

Abstract CREBBP mutations are highly recurrent in B-cell lymphomas and either inactivate its histone acetyltransferase (HAT) domain or truncate the protein. Herein, we show that these two classes of mutations yield different degrees of disruption of the epigenome, with HAT mutations being more severe and associated with inferior clinical outcome. Genes perturbed by CREBBP mutation are direct targets of the BCL6–HDAC3 onco-repressor complex. Accordingly, we show that HDAC3-selective inhibitors reverse CREBBP-mutant aberrant epigenetic programming, resulting in: (i) growth inhibition of lymphoma cells through induction of BCL6 target genes such as CDKN1A and (ii) restoration of immune surveillance due to induction of BCL6-repressed IFN pathway and antigen-presenting genes. By reactivating these genes, exposure to HDAC3 inhibitors restored the ability of tumor-infiltrating lymphocytes to kill DLBCL cells in an MHC class I and II–dependent manner, and synergized with PD-L1 blockade in a syngeneic model in vivo. Hence, HDAC3 inhibition represents a novel mechanism-based immune epigenetic therapy for CREBBP-mutant lymphomas. Significance: We have leveraged the molecular characterization of different types of CREBBP mutations to define a rational approach for targeting these mutations through selective inhibition of HDAC3. This represents an attractive therapeutic avenue for targeting synthetic vulnerabilities in CREBBP-mutant cells in tandem with promoting antitumor immunity. This article is highlighted in the In This Issue feature, p. 327