Letter | Published:

Somatic deletions of genes regulating MSH2 protein stability cause DNA mismatch repair deficiency and drug resistance in human leukemia cells

Nature Medicine volume 17, pages 12981303 (2011) | Download Citation


DNA mismatch repair enzymes (for example, MSH2) maintain genomic integrity, and their deficiency predisposes to several human cancers and to drug resistance. We found that leukemia cells from a substantial proportion of children (11%) with newly diagnosed acute lymphoblastic leukemia have low or undetectable MSH2 protein levels, despite abundant wild-type MSH2 mRNA. Leukemia cells with low levels of MSH2 contained partial or complete somatic deletions of one to four genes that regulate MSH2 degradation (FRAP1 (also known as MTOR), HERC1, PRKCZ and PIK3C2B); we also found these deletions in individuals with adult acute lymphoblastic leukemia (16%) and sporadic colorectal cancer (13.5%). Knockdown of these genes in human leukemia cells recapitulated the MSH2 protein deficiency by enhancing MSH2 degradation, leading to substantial reduction in DNA mismatch repair and increased resistance to thiopurines. These findings reveal a previously unrecognized mechanism whereby somatic deletions of genes regulating MSH2 degradation result in undetectable levels of MSH2 protein in leukemia cells, DNA mismatch repair deficiency and drug resistance.

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  1. 1.

    , & Constitutive deficiency in DNA mismatch repair. Clin. Genet. 71, 483–498 (2007).

  2. 2.

    et al. The human mutator gene homolog MSH2 and its association with hereditary nonpolyposis colon cancer. Cell 75, 1027–1038 (1993).

  3. 3.

    et al. The role of DNA mismatch repair in platinum drug resistance. Cancer Res. 56, 4881–4886 (1996).

  4. 4.

    et al. Msh2 deficiency attenuates but does not abolish thiopurine hematopoietic toxicity in Msh2−/− mice. Mol. Pharmacol. 64, 456–465 (2003).

  5. 5.

    et al. Role of postreplicative DNA mismatch repair in the cytotoxic action of thioguanine. Science 273, 1109–1111 (1996).

  6. 6.

    & Molecular origins of cancer: molecular basis of colorectal cancer. N. Engl. J. Med. 361, 2449–2460 (2009).

  7. 7.

    et al. Hereditary ovarian carcinoma: heterogeneity, molecular genetics, pathology, and management. Mol. Oncol. 3, 97–137 (2009).

  8. 8.

    Inherited susceptibility to colorectal cancer. Annu. Rev. Med. 56, 539–554 (2005).

  9. 9.

    et al. Germline, somatic and epigenetic events underlying mismatch repair deficiency in colorectal and HNPCC-related cancers. Oncogene 21, 7585–7592 (2002).

  10. 10.

    et al. Heritable somatic methylation and inactivation of MSH2 in families with Lynch syndrome due to deletion of the 3′ exons of TACSTD1. Nat. Genet. 41, 112–117 (2009).

  11. 11.

    & Expression of DNA mismatch repair proteins in acute lymphoblastic leukaemia and normal bone marrow. Adv. Exp. Med. Biol. 457, 579–583 (1999).

  12. 12.

    , & Microsatellite instability and p53 mutations are associated with abnormal expression of the MSH2 gene in adult acute leukemia. Blood 94, 733–740 (1999).

  13. 13.

    et al. Mismatch repair deficiency associated with overexpression of the MSH3 gene. Proc. Natl. Acad. Sci. USA 95, 8568–8573 (1998).

  14. 14.

    , , , & Induction of two DNA mismatch repair proteins, MSH2 and MSH6, in differentiated human neuroblastoma SH-SY5Y cells exposed to doxorubicin. J. Neurochem. 72, 974–979 (1999).

  15. 15.

    , & Mismatch G-T binding activity and MSH2 expression is quantitatively related to sensitivity of cells to methylating agents. Carcinogenesis 19, 567–573 (1998).

  16. 16.

    , , , & Degradation of mismatch repair hMutSα heterodimer by the ubiquitin-proteasome pathway. FEBS Lett. 562, 40–44 (2004).

  17. 17.

    et al. Modulation of mismatch repair and genomic stability by miR-155. Proc. Natl. Acad. Sci. USA 107, 6982–6987 (2010).

  18. 18.

    et al. Genome-wide analysis of genetic alterations in acute lymphoblastic leukaemia. Nature 446, 758–764 (2007).

  19. 19.

    et al. hMutSα is protected from ubiquitin-proteasome-dependent degradation by atypical protein kinase C ζ phosphorylation. J. Mol. Biol. 348, 63–74 (2005).

  20. 20.

    , & Acute lymphoblastic leukemia. N. Engl. J. Med. 350, 1535–1548 (2004).

  21. 21.

    & Thiopurines in current medical practice: molecular mechanisms and contributions to therapy-related cancer. Nat. Rev. Cancer 8, 24–36 (2008).

  22. 22.

    , & Regulation of translation initiation by FRAP/mTOR. Genes Dev. 15, 807–826 (2001).

  23. 23.

    , & Protein phosphatase 2A is a critical regulator of protein kinase C ζ signaling targeted by SV40 small t to promote cell growth and NF-κB activation. EMBO J. 16, 5662–5671 (1997).

  24. 24.

    et al. TSC1 stabilizes TSC2 by inhibiting the interaction between TSC2 and the HERC1 ubiquitin ligase. J. Biol. Chem. 281, 8313–8316 (2006).

  25. 25.

    et al. Regulation of mTOR function in response to hypoxia by REDD1 and the TSC1/TSC2 tumor suppressor complex. Genes Dev. 18, 2893–2904 (2004).

  26. 26.

    & TSC1 and TSC2 tumor suppressors antagonize insulin signaling in cell growth. Genes Dev. 15, 1383–1392 (2001).

  27. 27.

    & Role of class II phosphoinositide 3-kinase in cell signaling. Biochem. Soc. Trans. 35, 211–214 (2007).

  28. 28.

    , , , & Mouse models for hereditary nonpolyposis colorectal cancer. Cancer Res. 58, 248–255 (1998).

  29. 29.

    , , & Evidence for Msh2 haploinsufficiency in mice revealed by MNU-induced sister-chromatid exchange analysis. Br. J. Cancer 83, 1291–1294 (2000).

  30. 30.

    et al. Mouse embryonic stem cells carrying one or two defective Msh2 alleles respond abnormally to oxidative stress inflicted by low-level radiation. Proc. Natl. Acad. Sci. USA 95, 11915–11920 (1998).

  31. 31.

    et al. CDK8 is a colorectal cancer oncogene that regulates β-catenin activity. Nature 455, 547–551 (2008).

  32. 32.

    et al. Microdeletions are a general feature of adult and adolescent acute lymphoblastic leukemia: unexpected similarities with pediatric disease. Proc. Natl. Acad. Sci. USA 105, 6708–6713 (2008).

  33. 33.

    et al. Epigenetic phenotypes distinguish microsatellite-stable and -unstable colorectal cancers. Proc. Natl. Acad. Sci. USA 96, 12661–12666 (1999).

  34. 34.

    Functional interactions and signaling properties of mammalian DNA mismatch repair proteins. Cell Death Differ. 8, 1076–1092 (2001).

  35. 35.

    , , & Defective mismatch binding and a mutator phenotype in cells tolerant to DNA damage. Nature 362, 652–654 (1993).

  36. 36.

    , & DNA repair alterations in common pediatric malignancies. Med. Sci. Monit. 14, RA8–RA15 (2008).

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We gratefully acknowledge the subjects and parents who participated in this study and the outstanding technical support of the Hartwell Center for Bioinformatics and Biotechnology at St. Jude Children's Research Hospital. We also thank Y. Wang, T. Brooks, J. Smith, W. Du, S. Mukatira, Y. Chu, M. Needham, P. Hargrove, G. Stocco and S. Paugh for their advice and technical support; J. Groff for preparation of the figures; K. Crews, N. Kornegay and M. Wilkinson for their research database expertise; J.C. Panetta for his modeling expertise; J. Jenkins for his immunohistochemistry expertise; T. Kunkel and A.B. Clark (National Institute of Environmental Health Sciences) for providing the E. coli strains, the wild-type and mutant M13mp2 phage and for their contributions to our MMR experiments; and J. Luis Rosa (Universitat de Barcelona) for providing us with antibodies to HERC1. We thank M. Kastan and D. Green for their critical review and advice. This work was supported in part by grant R37 CA36401 (W.E.E. and M.V.R.), NIH National Institute of General Medical Sciences Pharmacogenomics Research Network grant U01 GM92666 (M.V.R. and W.E.E.), CGM is a Pew Scholar and a St. Baldrick's scholar, and St. Jude is supported by a Cancer Center Support Grant CA 21765 from the National Cancer Institute and by the American Lebanese Syrian Associated Charities (ALSAC). H.G., S.C. and P.H. were funded by the Intramural Research Program of the National Institute of Diabetes and Digestive and Kidney Diseases of the NIH.

Author information


  1. Hematological Malignancies Program, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.

    • Barthelemy Diouf
    • , Qing Cheng
    • , Natalia F Krynetskaia
    • , Wenjian Yang
    • , Meyling Cheok
    • , Deqing Pei
    • , Cheng Cheng
    • , Evgeny Y Krynetskiy
    • , William E Thierfelder
    • , Charles G Mullighan
    • , James R Downing
    • , Ching-Hon Pui
    • , Mary V Relling
    •  & William E Evans
  2. Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.

    • Barthelemy Diouf
    • , Qing Cheng
    • , Natalia F Krynetskaia
    • , Wenjian Yang
    • , Meyling Cheok
    • , Evgeny Y Krynetskiy
    • , William E Thierfelder
    • , Mary V Relling
    •  & William E Evans
  3. Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.

    • Deqing Pei
    •  & Cheng Cheng
  4. Hartwell Center for Bioinformatics and Biotechnology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.

    • Yiping Fan
  5. Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, US National Institutes of Health (NIH), Bethesda, Maryland, USA.

    • Hui Geng
    • , Siying Chen
    •  & Peggy Hsieh
  6. Department of Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.

    • Charles G Mullighan
    • , James R Downing
    •  & Ching-Hon Pui
  7. Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.

    • Ching-Hon Pui


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W.E.E. designed and supervised experiments and their analyses and wrote the manuscript with B.D. B.D., Q.C., N.F.K., M.C., E.Y.K., H.G., S.C., P.H., W.E.T. and C.G.M. performed experiments and participated in their analyses. J.R.D., C.G.M. and M.V.R. directed experiments and contributed to the genomic analyses. D.P., Y.F. and C.C. performed the statistical analyses. W.Y. led the genomic analyses in collaboration with other authors. C.-H.P. led the clinical trials and provided the ALL samples. All authors discussed the results and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to William E Evans.

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