Cancer Letters

Cancer Letters

Volume 422, 28 May 2018, Pages 56-69
Cancer Letters

Original Articles
SUV39H2 promotes colorectal cancer proliferation and metastasis via tri-methylation of the SLIT1 promoter

https://doi.org/10.1016/j.canlet.2018.02.023Get rights and content

Highlights

  • SUV39H2 is a novel prognostic factor of CRC.

  • SUV39H2 enhances CRC proliferation and metastasis both in vitro and in vivo.

  • SLIT1 is a critical downstream target of SUV39H2.

  • SUV39H2 directly binds to SLIT1 promoter and catalyzes H3K9 tri-methylation to inhibit SLIT1 transcription.

Abstract

Suppressor of variegation 3–9 homolog 2 (SUV39H2) is a member of the SUV39H subfamily of lysine methyltransferases. Its role in colorectal cancer (CRC) proliferation and metastasis has remained unexplored. Here, we determined that SUV39H2 was upregulated in CRC tissues compared with that in adjacent non-neoplastic tissues. Further statistical analysis revealed that high SUV39H2 expression was strongly associated with distant metastasis (P = 0.016) and TNM stage (P = 0.038) and predicted a shorter overall survival (OS; P = 0.018) and progression-free survival (PFS; P = 0.018) time for CRC patients. Both in vitro and in vivo assays demonstrated that ectopically expressed SUV39H2 enhanced CRC proliferation and metastasis, while SUV39H2 knockdown inhibited CRC proliferation and metastasis. A molecular screen of SUV39H2 targets found that SUV39H2 negatively regulated the expression of SLIT guidance ligand 1 (SLIT1). Moreover, rescue assays suggested that SLIT1 could antagonize the function of SUV39H2 in CRC. Mechanistic studies indicated that SUV39H2 can directly bind to the SLIT1 promoter, suppressing SLIT1 transcription by catalyzing histone H3 lysine 9 (H3K9) tri-methylation. In summary, we propose that SUV39H2 can predict CRC patient prognosis and stimulate CRC malignant phenotypes via SLIT1 promoter tri-methylation.

Introduction

Colorectal cancer (CRC) strongly contributes to the morbidity and mortality of cancer patients [1]. Genetic abnormalities have been widely studied and shown to promote or drive CRC pathogenesis [[2], [3], [4], [5], [6], [7]]. However, genetic alterations occur at a low frequency and are not sufficient to explain all the mechanisms underlying CRC initiation and progression [8].

Epigenetics describes heritable phenotype changes without DNA sequence alteration [9]. The primary epigenetic mechanisms include histone posttranslational modifications (PTMs), DNA methylation, ATP-dependent nucleosome remodeling and non-coding RNA regulation [9,10]. These mechanisms mediate transcriptional programs by regulating chromatin structure and conferring cell plasticity and selective advantages during environmental stress, exerting significant influences on cellular characteristics [8]. Though it has been widely accepted that epigenetic perturbations are critical for cancer [10], the detailed effects of specific epigenetic regulators in CRC need to be further investigated.

Histone PTMs primarily occur in N-terminal “tails” [11,12], including many modification types at different histone residues [[13], [14], [15], [16], [17]]. PTMs play critical roles in DNA template events, such as transcription, DNA repair, replication, and recombination [12,18], by changing the state of the chromosome or altering the intra- and inter-nucleosome contacts. Many proteins act as readers or effectors and can promote or suppress the expression of certain genes by recognizing and binding to specific chemical modifications of the histone, translating the histone code into useful biological activities [[19], [20], [21], [22]]. A series of histone-modifying enzymes [23,24] act alone or in combination to fine-tune expression based on extracellular stimuli.

Of the PTM types, histone methylation is the most specific and well-characterized modification [12], occurring on the arginine and lysine residuals of histones H3 and H4. In this article, we focused on H3 lysine 9 (H3K9) tri-methylation, a mark for transcriptionally silent chromatin [25,26].

Suppressor of variegation 3–9 homolog 2 (SUV39H2) is the second H3K9 selective histone methyltransferase (HMT) isolated and characterized in murines [27]. SUV39H2 catalyzes H3K9 tri-methylation and inhibits gene expression [25,26,28]. It can also regulate telomere length [29,30] and genome stability and play a critical function in male germ cell and the embryogenesis of mice [31,32]. Moreover, studies have demonstrated that Suv39H2 knockout protects mice from myocardial infarction and nonalcoholic steatohepatitis [33,34]. In addition to important roles in the physiological activities of mice, evidence indicates that SUV39H2 also participates in hepatocellular carcinoma development [35]. However, the functions and mechanisms of SUV39H2 in CRC pathogenesis and progression have not been investigated to date.

In this study, we revealed that high SUV39H2 expression positively predicted poor prognosis of CRC patients. Moreover, SUV39H2 promoted CRC proliferation and metastasis in vitro and in vivo. Mechanistic exploration using gene expression microarrays and chromatin immunoprecipitation (ChIP) analysis demonstrated that SLIT guidance ligand 1 (SLIT1) was a novel downstream target of SUV39H2. Further functional rescue experiments indicated that SUV39H2 promoted CRC progression in a SLIT1-dependent manner.

Section snippets

Cell culture

The 293 T cell line and five human CRC cell lines (HCT-15, SW620, HT-29, DLD1, HCT116) were purchased from American Type Culture Collection (ATCC, Manassas, VA, USA). NCM460 and SW1116, originating from normal and colon cancer mucosal epithelium, respectively, were kindly provided by Professor Xie Dan (Cancer Institute, Sun Yat-sen University). The ATCC-recommended conditions, including a specific medium with 10% fetal bovine serum (FBS, Gibco, Grand Island, NY, USA), penicillin (100 units/ml),

SUV39H2 is frequently upregulated in CRC tissues

Analysis of 43 histone methyltransferases and demethyltransferases in the published gene expression microarray GSE8671, which includes 32 CRC neoplastic tissues and the paired normal tissues, indicated that SUV39H2 was the most highly expressed gene in neoplastic tissues compared with that in normal tissues (Fig. S1A and S1B, P < 0.001). We also conducted real-time PCR (RT-PCR) to verify the result of the microarray analysis in CRC cells lines and paired CRC tissues. The result demonstrated

Discussion

Lysine methylation catalyzed by lysine methyltransferases (KMTs), which primarily include a family of SET-domain containing proteins, has been widely studied and proven to participate in several important cellular events [[46], [47], [48], [49]]. The SUV39 family is a subfamily of KMTs that mediates H3K9 methylation, representing the repressive status of gene expression. SUV39H1 and SUV39H2, the two critical regulators, mediate H3K9 tri-methylation (H3K9me3) distributed in heterochromatin

Conflicts of interest

The authors declare no conflict of interest.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (No. 81771701, 81472252, 81772885). We thank the members of the laboratory for helpful comments on the article.

References (77)

  • M.K. Schuhmacher

    Activity and specificity of the human SUV39H2 protein lysine methyltransferase

    Biochim. Biophys. Acta

    (2015)
  • J.C. Rice

    Histone methyltransferases direct different degrees of methylation to define distinct chromatin domains

    Mol. Cell

    (2003)
  • A.H. Peters

    Loss of the Suv39h histone methyltransferases impairs mammalian heterochromatin and genome stability

    Cell

    (2001)
  • A. Bulut-Karslioglu

    Suv39h-dependent H3K9me3 marks intact retrotransposons and silences LINE elements in mouse embryonic stem cells

    Mol. Cell

    (2014)
  • A.C. Battisti

    A subset of chicken statoacoustic ganglion neurites are repelled by Slit1 and Slit2

    Hear. Res.

    (2014)
  • Q. Liu

    BORIS up-regulates OCT4 via histone methylation to promote cancer stem cell-like properties in human liver cancer cells

    Canc. Lett.

    (2017)
  • Y. Mao

    Quikgene: a gene synthesis method integrated with ligation-free cloning

    Anal. Biochem.

    (2011)
  • M. Garber

    A high-throughput chromatin immunoprecipitation approach reveals principles of dynamic gene regulation in mammals

    Mol. Cell

    (2012)
  • S. Biswas et al.

    Epigenetics in cancer: fundamentals and beyond

    Pharmacol. Ther.

    (2017)
  • B. Lehnertz

    Suv39h-Mediated histone H3 lysine 9 methylation directs DNA methylation to major satellite repeats at pericentric heterochromatin

    Curr. Biol.

    (2003)
  • F. Fuks

    DNA methylation and histone modifications: teaming up to silence genes

    Curr. Opin. Genet. Dev.

    (2005)
  • T. Kidd

    Roundabout controls axon crossing of the CNS midline and defines a novel subfamily of evolutionarily conserved guidance receptors

    Cell

    (1998)
  • B. Biteau et al.

    Slit/Robo signaling regulates cell fate decisions in the intestinal stem cell lineage of Drosophila

    Cell Rep.

    (2014)
  • M.S. Ballard et al.

    A roundabout way to cancer

    Adv. Canc. Res.

    (2012)
  • J. Jin

    Epigenetic inactivation of SLIT2 in human hepatocellular carcinomas

    Biochem. Biophys. Res. Commun.

    (2009)
  • R.L. Siegel

    Colorectal cancer statistics, 2017

    CA A Cancer J. Clin.

    (2017)
  • E.R. Fearon

    Molecular genetics of colorectal cancer

    Annu. Rev. Pathol.

    (2011)
  • Cancer Genome Atlas N

    Comprehensive molecular characterization of human colon and rectal cancer

    Nature

    (2012)
  • J. Drost

    Sequential cancer mutations in cultured human intestinal stem cells

    Nature

    (2015)
  • X.L. Li

    P53 mutations in colorectal cancer - molecular pathogenesis and pharmacological reactivation

    World J. Gastroenterol.

    (2015)
  • M. Nakayama

    Intestinal cancer progression by mutant p53 through the acquisition of invasiveness associated with complex glandular formation

    Oncogene

    (2017)
  • S.B. Baylin et al.

    Epigenetic determinants of cancer

    Cold Spring Harbor Perspectives in Biology

    (2016)
  • D.E. Sterner et al.

    Acetylation of histones and transcription-related factors

    Microbiol. Mol. Biol. Rev.

    (2000)
  • K.B. Glaser

    Gene expression profiling of multiple histone deacetylase (HDAC) inhibitors: defining a common gene set produced by HDAC inhibition in T24 and MDA carcinoma cell lines

    Mol. Canc. Therapeut.

    (2003)
  • B.D. Strahl et al.

    The language of covalent histone modifications

    Nature

    (2000)
  • A. Unnikrishnan et al.

    Dynamic changes in histone acetylation regulate origins of DNA replication

    Nat. Struct. Mol. Biol.

    (2010)
  • A.C. Belkina et al.

    BET domain co-regulators in obesity, inflammation and cancer

    Nat. Rev. Canc.

    (2012)
  • S.C. Dillon

    The SET-domain protein superfamily: protein lysine methyltransferases

    Genome Biol.

    (2005)
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    These authors contributed equally to this work.

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