International Journal of Colorectal Disease

, Volume 19, Issue 2, pp 95–101 | Cite as

Hypomethylation of L1 retrotransposons in colorectal cancer and adjacent normal tissue

  • Catherine M. Suter
  • David I. Martin
  • Robyn L. WardEmail author
Original Article


Background and aims

Malignant cells often exhibit perturbations in the pattern of cytosine methylation. Hypermethylation of CpG islands has been extensively documented, but genome-wide hypomethylation is also a common feature of malignant cells. The bulk of cytosine methylation in the mammalian genome occurs on repetitive elements. This study analysed the methylation status of L1 retrotransposons in colorectal cancer.

Patients and methods

Methylation-sensitive Southern blotting was used to determine L1 promoter methylation in colon tumours, adjacent normal tissue, and normal colonic mucosa from healthy individuals.


Hypomethylation of L1 promoter sequences was detected in all tumours but was also detected in the histologically normal colonic mucosa of 6 of 19 cancer patients, even at a considerable distance from the tumour. L1 hypomethylation was not detected in matched normal peripheral blood, lymph node or smooth muscle tissue from cancer patients or in the colonic mucosa of 14 healthy individuals. We also assayed for the total proportion of methylated CpG in normal bowel specimens from normal and colon cancer patients. Normal mucosa from cancer patients exhibited lower levels of genomic methylation than the mucosa from healthy individuals, and levels were significantly lower in those patients exhibiting L1 promoter hypomethylation.


These results suggest that genomic hypomethylation is an early event in tumourigenesis. Progressive demethylation of L1 promoter sequences could lead to disturbance of normal gene expression and facilitate the process of neoplastic progression.


Epigenetic Retroelement Cytosine methylation Transcriptional interference 


  1. 1.
    Kazazian HH Jr (1998) Mobile elements and disease. Curr Opin Genet Dev 8:343–350PubMedGoogle Scholar
  2. 2.
    Lander ES, Linton LM, Birren B, Nusbaum C, Zody MC, Baldwin J, Devon K, Dewar K, Doyle M, FitzHugh W et al (2001) Initial sequencing and analysis of the human genome. Nature 409:860–921PubMedGoogle Scholar
  3. 3.
    Venter JC, Adams MD, Myers EW, Li PW, Mural RJ, Sutton GG, Smith HO, Yandell M, Evans CA, Holt RA et al (2001) The sequence of the human genome. Science 291:1304–1351PubMedGoogle Scholar
  4. 4.
    Smit AF (1999) Interspersed repeats and other mementos of transposable elements in mammalian genomes. Curr Opin Genet Dev 9:657–663PubMedGoogle Scholar
  5. 5.
    Sassaman DM, Dombroski BA, Moran JV, Kimberland ML, Naas TP, DeBerardinis RJ, Gabriel A, Swergold GD, Kazazian HH Jr (1997) Many human L1 elements are capable of retrotransposition. Nat Genet 16:37–43PubMedGoogle Scholar
  6. 6.
    Saxton JA, Martin SL (1998) Recombination between subtypes creates a mosaic lineage of LINE-1 that is expressed and actively retrotransposing in the mouse genome. J Mol Biol 280:611–622CrossRefPubMedGoogle Scholar
  7. 7.
    Morgan HD, Sutherland HG, Martin DI, Whitelaw E (1999) Epigenetic inheritance at the agouti locus in the mouse. Nat Genet 23:314–318PubMedGoogle Scholar
  8. 8.
    Burgers WA, Fuks F, Kouzarides T (2002) DNA methyltransferases get connected to chromatin. Trends Genet 18:275–277CrossRefPubMedGoogle Scholar
  9. 9.
    Herman JG, Latif F, Weng Y, Lerman MI, Zbar B, Liu S, Samid D, Duan DS, Gnarra JR, Linehan WM et al (1994) Silencing of the VHL tumor-suppressor gene by DNA methylation in renal carcinoma. Proc Natl Acad Sci U S A 91:9700–9704PubMedGoogle Scholar
  10. 10.
    Yoshiura K, Kanai Y, Ochiai A, Shimoyama Y, Sugimura T, Hirohashi S (1995) Silencing of the E-cadherin invasion-suppressor gene by CpG methylation in human carcinomas. Proc Natl Acad Sci USA 92:7416–7419PubMedGoogle Scholar
  11. 11.
    Esteller M, Silva JM, Dominguez G, Bonilla F, Matias-Guiu X, Lerma E, Bussaglia E, Prat J, Harkes IC, Repasky EA et al (2000) Promoter hypermethylation and BRCA1 inactivation in sporadic breast and ovarian tumors. J Natl Cancer Inst 92:564–569PubMedGoogle Scholar
  12. 12.
    Herman JG, Baylin SB (2000) Promoter-region hypermethylation and gene silencing in human cancer. Curr Top Microbiol Immunol 249:35–54PubMedGoogle Scholar
  13. 13.
    Roman-Gomez J, Castillejo JA, Jimenez A, Gonzalez MG, Moreno F, Rodriguez Mdel C, Barrios M, Maldonado J, Torres A (2002) 5’ CpG island hypermethylation is associated with transcriptional silencing of the p21 (CIP1/WAF1/SDI1) gene and confers poor prognosis in acute lymphoblastic leukemia. Blood 99:2291–2296CrossRefPubMedGoogle Scholar
  14. 14.
    Goelz SE, Vogelstein B, Hamilton SR, Feinberg AP (1985) Hypomethylation of DNA from benign and malignant human colon neoplasms. Science 228:187–190PubMedGoogle Scholar
  15. 15.
    Feinberg AP, Gehrke CW, Kuo KC, Ehrlich M (1988) Reduced genomic 5-methylcytosine content in human colonic neoplasia. Cancer Res 48:1159–1161PubMedGoogle Scholar
  16. 16.
    De Smet C, De Backer O, Faraoni I, Lurquin C, Brasseur F, Boon T (1996) The activation of human gene MAGE-1 in tumor cells is correlated with genome-wide demethylation. Proc Natl Acad Sci USA 93:7149–7153CrossRefPubMedGoogle Scholar
  17. 17.
    Jones PA, Laird PW (1999) Cancer epigenetics comes of age. Nat Genet 21:163–167CrossRefPubMedGoogle Scholar
  18. 18.
    Bariol C, Suter CM, Cheong KF, Ku S, Hawkins N, Ward RL (2003) The relationship between hypomethylation and CpG island methylation in colorectal neoplasia. Am J Pathol 162:1361–1371PubMedGoogle Scholar
  19. 19.
    Yoder JA, Walsh CP, Bestor TH (1997) Cytosine methylation and the ecology of intragenomic parasites. Trends Genet 13:335–340PubMedGoogle Scholar
  20. 20.
    Crowther PJ, Doherty JP, Linsenmeyer ME, Williamson MR, Woodcock DM (1991) Revised genomic consensus for the hypermethylated CpG island region of the human L1 transposon and integration sites of full length L1 elements from recombinant clones made using methylation-tolerant host strains. Nucleic Acids Res 19:2395–2401PubMedGoogle Scholar
  21. 21.
    Alves G, Tatro A, Fanning T (1996) Differential methylation of human LINE-1 retrotransposons in malignant cells. Gene 176:39–44CrossRefPubMedGoogle Scholar
  22. 22.
    Thayer RE, Singer MF, Fanning TG (1993) Undermethylation of specific LINE-1 sequences in human cells producing a LINE-1-encoded protein. Gene 133:273–277CrossRefPubMedGoogle Scholar
  23. 23.
    Jurgens B, Schmitz-Drager BJ, Schulz WA (1996) Hypomethylation of L1 LINE sequences prevailing in human urothelial carcinoma. Cancer Res 56:5698–5703PubMedGoogle Scholar
  24. 24.
    Florl AR, Lower R, Schmitz-Drager BJ, Schulz WA (1999) DNA methylation and expression of LINE-1 and HERV-K provirus sequences in urothelial and renal cell carcinomas. Br J Cancer 80:1312–1321CrossRefPubMedGoogle Scholar
  25. 25.
    Takai D, Yagi Y, Habib N, Sugimura T, Ushijima T (2000) Hypomethylation of LINE1 retrotransposon in human hepatocellular carcinomas, but not in surrounding liver cirrhosis. Jpn J Clin Oncol 30:306–309CrossRefPubMedGoogle Scholar
  26. 26.
    McClintock B (1968) The states of a gene locus in maize. Carnegie Institute of Washington Yearbook 66:20–28Google Scholar
  27. 27.
    Fincham JR, Sastry GR (1974) Controlling elements in maize. Annu Rev Genet 8:15–50CrossRefPubMedGoogle Scholar
  28. 28.
    Martienssen R, Baron A (1994) Coordinate suppression of mutations caused by Robertson’s mutator transposons in maize. Genetics 136:1157–1170PubMedGoogle Scholar
  29. 29.
    Kashkush K, Feldman M, Levy AA (2002) Transcriptional activation of retrotransposons alters the expression of adjacent genes in wheat. Nat Genet 16:16Google Scholar
  30. 30.
    Whitelaw E, Martin DI (2001) Retrotransposons as epigenetic mediators of phenotypic variation in mammals. Nat Genet 27:361–365CrossRefPubMedGoogle Scholar
  31. 31.
    Hata K, Sakaki Y (1997) Identification of critical CpG sites for repression of L1 transcription by DNA methylation. Gene 189:227–234CrossRefPubMedGoogle Scholar
  32. 32.
    Woodcock DM, Lawler CB, Linsenmeyer ME, Doherty JP, Warren WD (1997) Asymmetric methylation in the hypermethylated CpG promoter region of the human L1 retrotransposon. J Biol Chem 272:7810–7816CrossRefPubMedGoogle Scholar
  33. 33.
    Cui H, Horon IL, Ohlsson R, Hamilton SR, Feinberg AP (1998) Loss of imprinting in normal tissue of colorectal cancer patients with microsatellite instability. Nat Med 4:1276–1280CrossRefPubMedGoogle Scholar
  34. 34.
    Cui H, Onyango P, Brandenburg S, Wu Y, Hsieh CL, Feinberg AP (2002) Loss of imprinting in colorectal cancer linked to hypomethylation of H19 and IGF2. Cancer Res 62:6442–6446PubMedGoogle Scholar
  35. 35.
    Cui H, Cruz-Correa M, Giardiello FM, Hutcheon DF, Kafonek DR, Brandenburg S, Wu Y, He X, Powe NR, Feinberg AP (2003) Loss of IGF2 imprinting: a potential marker of colorectal cancer risk. Science 299:1753–1755CrossRefPubMedGoogle Scholar
  36. 36.
    Suter CM, Norrie M, Ku SL, Cheong KF, Tomlinson I, Ward RL (2003) CpG island methylation is a common finding in colorectal cancer cell lines. Br J Cancer 88:413–419CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Catherine M. Suter
    • 1
  • David I. Martin
    • 2
  • Robyn L. Ward
    • 1
    Email author
  1. 1.Medical Oncology DepartmentSt. Vincent’s HospitalSydneyAustralia
  2. 2.Victor Chang Cardiac Research InstituteSydneyAustralia

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