Demethylation and Up-Regulation of an Oncogene after Hypomethylating Therapy

Yao-Chung Liu1, Junsu Kwon1, Emiliano Fabiani1

  • 1From the Department of Pathology, Brigham and Women's Hospital (Y.-C.L., C. Gao, Jun Liu, J.Y., L. Chai), Harvard Stem Cell Institute, Harvard Medical School (A.I.J., M.A.B., D.G.T.), and the Department of Medical Oncology, Dana-Farber Cancer Institute (R.P.) - all in Boston; the Division of Hematology, Department of Medicine, Taipei Veterans General Hospital (Y.-C.L.), and the Faculty of Medicine and the Program in Molecular Medicine, Institute of Biopharmaceutical Sciences, School of Life Science, National Yang Ming Chiao Tung University (Y.-C.L., J.-H.L.) - both in Taipei, Taiwan; the Cancer Science Institute of Singapore, Singapore (J.K., Y.V.L., H.Y., M.A.B., D.G.T.); the Department of Biomedicine and Prevention, University of Rome Tor Vergata (E.F., G.F., L.V., C. Gurnari, M.T.V.), and UniCamillus-Saint Camillus International University of Health Sciences (E.F.), Rome, and Cellular Signaling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna (M.Y.F., L. Cocco), and IRCCS Azienda Ospedaliero-Universitaria di Bologna, Istituto di Ematologia "Seràgnoli" (C.F.), Bologna - all in Italy; the National Clinical Research Center for Blood Diseases and State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China (Z.X., Jinqin Liu, H.H.); and the School of Medical Sciences and Lowy Cancer Research Centre (J.A.I.T., J.E.P.) and Prince of Wales Clinical School and Lowy Cancer Research Centre (A.U., J.E.P.), Faculty of Medicine, University of New South Wales, Sydney, and the Department of Hematology, Prince of Wales Hospital, Randwick, NSW (J.E.P.) - both in Australia.

Abstract

Insights

Hypomethylating agents can up-regulate the oncogene SALL4 in cancer patients, potentially worsening outcomes. This study identified a critical CpG island in the SALL4 gene

Area of Science:

  • Oncology
  • Molecular Biology
  • Epigenetics

Background:

  • Hypomethylating agents are used in cancer therapy.
  • Their potential to reactivate oncogenes is not fully understood.

Purpose of the Study:

  • To investigate the effect of hypomethylating agents on SALL4 oncogene expression.
  • To explore the relationship between SALL4 up-regulation, treatment response, and clinical outcomes in myelodysplastic syndrome.

Main Methods:

  • Analysis of patient samples before and after hypomethylating agent treatment.
  • Utilized leukemic cell lines to study SALL4 methylation and expression.
  • Employed CRISPR-DNMT1-interacting RNA (CRISPR-DiR) for locus-specific demethylation.

Main Results:

  • SALL4 up-regulation was observed in 30-40% of patients post-treatment and associated with worse outcomes.
  • Demethylation of a 5' untranslated region CpG island was critical for SALL4 expression.
  • Confirmed hypomethylating agent treatment induced demethylation and SALL4 up-regulation.

Conclusions:

  • Demethylation and up-regulation of oncogenes by hypomethylating agents can occur.
  • Findings highlight the need for further investigation into this phenomenon.

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