SMYD3 promotes colon adenocarcinoma (COAD) progression by mediating cell proliferation and apoptosis
EXPERIMENTAL AND THERAPEUTIC MEDICINE
Authors: Yue, Fu-Ren; Wei, Zhi-Bin; Yan, Rui-Zhen; Guo, Qiu-Hong; Liu, Bing; Zhang, Jing-Hui; Li, Zheng
Abstract
Colon adenocarcinoma (COAD) is a type of common malignant tumor originating in the digestive tract. Recently, targeted therapy has had significant effects on the treatment of COAD. However, more effective molecular targets need to be developed. SET and MYND domain-containing protein 3 (SMYD3) is a type of methyltransferase which methylates histone and non-histone proteins. The effects of SMYD3 on cancer progression and metastasis have been widely revealed. However, its possible role in COAD remains unclear. The current study demonstrated that SMYD3 expression was upregulated in human COAD tissues via analyzing the The Cancer Genome Atlas (TCGA) database and the immunohistochemical assays. Furthermore, the expression of SMYD3 was correlated with prognosis and tumor stage (P=0.038) in patients with COAD. Colony formation, MTT, FCM assays and animal assays indicated SMYD3 affected the proliferation, apoptosis and the cell cycle of COAD cells in vitro and promoted tumor growth in mice in vivo. In summary, the results demonstrated the effects of SMYD3 on COAD progression and we hypothesized that SMYD3 is a novel molecular target for COAD treatment.
O-GlcNAcylation Links Nutrition to the Epigenetic Downregulation of UNC5A during Colon Carcinogenesis
CANCERS
Authors: Decourcelle, Amelie; Very, Ninon; Djouina, Madjid; Loison, Ingrid; Thevenet, Julien; Body-Malapel, Mathilde; Lelievre, Eric; Coqueret, Olivier; Leprince, Dominique; Yazidi-Belkoura, Ikram El; Dehennaut, Vanessa
Abstract
Simple Summary Nutritional disorders represent major risk factors for colorectal cancer according to mechanisms of action that are still insufficiently known. The aim of our study was to investigate the putative involvement of nutrition in the epigenetic downregulation of the tumor suppressor genes of the UNC5 (Uncoordinated 5) family during colonic carcinogenesis and to understand its molecular relays. Herein, we provided evidence that the consumption of a High Carbohydrate Diet worsens colon carcinogenesis in mice and is correlated with the downregulation of several members of the UNC5 family whose UNC5A (Uncoordinated 5A). Mechanistically, we identified the nutritional sensor O-GlcNAcylation as one of the molecular relays that regulate the recruitment of the PRC2 complex onto the UNC5A promoter to repress its transcription. While it is now accepted that nutrition can influence the epigenetic modifications occurring in colorectal cancer (CRC), the underlying mechanisms are not fully understood. Among the tumor suppressor genes frequently epigenetically downregulated in CRC, the four related genes of the UNC5 family: UNC5A, UNC5B, UNC5C and UNC5D encode dependence receptors that regulate the apoptosis/survival balance. Herein, in a mouse model of CRC, we found that the expression of UNC5A, UNC5B and UNC5C was diminished in tumors but only in mice subjected to a High Carbohydrate Diet (HCD) thus linking nutrition to their repression in CRC. O-GlcNAcylation is a nutritional sensor which has enhanced levels in CRC and regulates many cellular processes amongst epigenetics. We then investigated the putative involvement of O-GlcNAcylation in the epigenetic downregulation of the UNC5 family members. By a combination of pharmacological inhibition and RNA interference approaches coupled to RT-qPCR (Reverse Transcription-quantitative Polymerase Chain Reaction) analyses, promoter luciferase assay and CUT&RUN (Cleavage Under Target & Release Using Nuclease) experiments, we demonstrated that the O-GlcNAcylated form of the histone methyl transferase EZH2 (Enhancer of Zeste Homolog 2) represses the transcription of UNC5A in human colon cancer cells. Collectively, our data support the hypothesis that O-GlcNAcylation could represent one link between nutrition and epigenetic downregulation of key tumor suppressor genes governing colon carcinogenesis including UNC5A.