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Junran Zhang, M.D.,Ph.D.

DNA double strand breaks (DSB) represent the most dangerous type of DNA lesion, because incorrectly repaired DSB can result in genomic instability, a major driving force in the onset and development of cancer. Cells that are deficient in DSB repair are sensitive to the lethal effect of ionizing radiation (IR) and chemotherapeutic drugs that cause DNA DSB. A picture is emerging in which perturbations of DSB repair that promote carcinogenesis by causing genomic instability may also be the Achilles' heel of the cancers. Thus, understanding the molecular mechanisms that are involved in DNA DSB responses has become a central issue in cancer biology and radiation biology. A major focus of my laboratory is to understand the mechanisms of how the repair of DNA DSB protects against carcinogenesis and how interruption of DSB responses sensitizes the tumor cells to IR and chemotherapeutic drugs. In addition to investigating DNA DSB response pathways, our group recently started a new avenue of investigation into basic cell signaling. Our work has shown that replication protein A (RPA), a protein initially considered as an important factor involving DNA replication and DNA damage response, plays an important role in inhibition of AKT activity via association with E3 ligase NEDD4-1. Therefore, understanding the molecular mechanism by which RPA inhibits AKT and its implication for cancer therapy is the other focus in my laboratory.

Three major ongoing research projects in my group:

  • ATR signaling and BRCA1 function in homologous recombination mediated repair in response to replication arrest.
  • Crosstalk of BRCA1 and 53BP1 in DNA DSB response and cancer therapy.
  • The role of RPA in inhibition of AKT signaling and cancer therapy.


  • PhD, Environmental Health, Toxicology , Shanghai Medical School , Shanghai, China  
  • MS, Environmental Health, Toxicology, Shanxi Medical School, Shanxi, China
  • MD,  Shanxi Medical College, Shanxi, China

Academic Positions/Employment:

  • 2000 - 2005: Post-Doctoral Research Fellow, Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
  • 2005 - 2007: Instructor, Department of Radiation Oncology
    Radiation and Cancer Biology Division
    Washington University School of Medicine, St. Louis, MO
  • 2007 - 2011: Assistant Professor, Department of Radiation Oncology
    Radiation and Cancer Biology Division
    Washington University School of Medicine, St. Louis, MO
  • 2011 - Present: Assistant Professor, Department of Radiation Oncology
    Case Western Reserve University School of Medicine, Cleveland, OH

Publication as a Post-Doctoral Research Fellow

  • Feng Z, Kachnic L, Zhang J, Powell SN and Xia F. DNA Damage Induces p53-Dependent BRCA1 Nuclear Export. Journal of Biological Chemistry,2004, 279(27):28574-28584.  PMID:  15087457
  • Zhang J, Willers H, Feng Z, Ghosh JC, Kim S, Weaver DT, Chung JH, Powell SN and Xia F. Chk2 Phosphorylation of BRCA1 Regulates DNA Double-Strand Break Repair. Molecular Cell Biology, 2004, 24(2):708-18.   PMID:  14701743
  • Litman R, Peng M, Jin Z, Zhang F, Zhang J ,Powell SN, Andreassen PR and Cantor SB. BACH1 is Critical for Homologous Recombination and Appears to be the Fanconi Anemia Gene Product FANCJ. Cancer Cell, 2005 8(3), 255-265.  PMID:  16153896
  • Zhang J and Powell SN. The Role of the BRCA1 Tumor Suppressor in DNA Double-Strand Break Repair. Molecular Cancer Research, 2005, 3(10):531-539.  PMID:  16254187
  • Zhang J, Ma Z, Treszezamsky A and Powell SN. MDC1 Interacts with Rad51 and Facilitates Homologous Recombination. Nature Structure Molecular Biology. 2005; 12(10):902-909.   PMID:  16186822
  • Zhang J*, Zhuang J*, Willers H, Chung J, van Gent DC, Hallahan DE, Powell SN and Xia F.  Chk2-Mediated Phosphorylation of BRCA1 Regulates the Fidelity of Non-homologous End-joining.  Cancer Research, 66(3):1401-8 2006. (*Contribute equally with first author)  PMID:  16452195
  • Pandita RK, Sharma GG, Laszlo A, Hopkins KM, Davey S, Chakhparonian M, Gupta A, Wellinger RJ, Zhang J, Powell SN, Roti Roti J, Lieberman HB and Pandita TK.  Mammalian Rad9 Plays a Role in Telomere Stability, S and G2 Phase Specific Cell Survival and Homologous Recombinational Repair.  Molecular Cell Biology, 26(5), 1850-64, 2006.  PMID:  16479004
  • Ma Z, Gibson SL, Byrne MA, Byrne MA, Zhang J, white MF and Shaw LM. Suppression of Insulin Receptor Substrate-I (IRS-1) Promotes Mammary Tumor Metastasis. Molecular Cell Biology, 26(24):9338-51, 2006.  PMID:  17303605
  • Treszezamsky AD., Feng Z, Zhang J, Tokadjian C, Kachnic LA. Powell SN. BRCA1 and BRCA2 Deficient Cells are Sensitive to Etoposide-Induced DNA Double Strand Breaks via Topoisomerase IICancer Research, 67(15):7078-81, 2007.   PMID: 17671173

Publications from Dr. Junran Zhang laboratory

  • Shi W, Ma Z, Willers H, Akhtar KScott SPZhang JQ, Powell S and Zhang J.  Disassembly of MDC1 Foci is Controlled by Ubiquitin-Proteasome Dependent Degradation. Journal of Biological Chemistry, 2008, 283(46):31608-16. PMID: 18757370
  • Shi W, Feng ZH, Zhang JQ, Gonzalez-Suarez Ignacio, Vander Waal R, Powell SN., Wu XH., Roti Roti J, Gonzalo S and Zhang J. The Role of RPA2 Phosphorylation in Homologous Recombination in Response to Replication Arrest. Carcinogenesis, 2010, 31(6):994-1002. PMID: 20130019
  • Chen H, Ma Z, Ignacio G, Gonzalez-Suarez Ignacio, VanderWall  R,  Roti Roti J, Gonzalo S and  Zhang J. mTOR Inhibitor, Rapamycin Inhibits DNA Double Strand Breaks Repair   Radiation Research, 2011, 175, 214-224. PMID: 21268715
  • Helmink BA., Tubbs A, Dorsett Y, Bednarski JJ, Walker LM, Feng Z, Sharma G, Baer R, McKinnon PJ, Zhang J, Bassing CH and Sleckman BP.  H2AX Inhibits CtIP-Mediated DNA End Resection and Aberrant Homology-Mediated Repair in G1-Phase Cells. Nature, 2011, 469 (7329):245-9.PMID: 21160476
  • Redwood AB, Perkins SM, Vanderwaal RP, Feng Z, Biehl KJ, Gonzalez-Suarez I, Morgado-Palacin L, Roti-Roti JL, Stewart CL, Zhang J, and Gonzalo S. A-type Lamins are Required for DNA Repair by Non-homologous End-joining and Homologous Recombination.  Cell Cycle 2011, 10(15). PMID: 21701264
  • Feng ZH, Zhang J. A Dual Role of BRCA1 in Two Distinct Homologous Recombination Mediated Repair in Response to Replication Arrest. Nucleic Acids Res. 2012, 40(2):726-38. PMID: 21954437
Case Western Reserve University

Junran Zhang, M.D.,Ph.D.

Assistant Professor of Radiation Oncology
Case Western Reserve University
School of Medicine
junran. zhang@
Phone: 216-368-1140
Fax: 216-368-1142