DNA repair mechanisms in cancer development and therapy

Abstract

DNA damage has been long recognized as causal factor for cancer development. When erroneous DNA repair leads to mutations or chromosomal aberrations affecting oncogenes and tumor suppressor genes, cells undergo malignant transformation resulting in cancerous growth. Genetic defects can predispose to cancer: mutations in distinct DNA repair systems elevate the susceptibility to various cancer types. However, DNA damage not only comprises a root cause for cancer development but also continues to provide an important avenue for chemo- and radiotherapy. Since the beginning of cancer therapy, genotoxic agents that trigger DNA damage checkpoints have been applied to halt the growth and trigger the apoptotic demise of cancer cells. We provide an overview about the involvement of DNA repair systems in cancer prevention and the classes of genotoxins that are commonly used for the treatment of cancer. A better understanding of the roles and interactions of the highly complex DNA repair machineries will lead to important improvements in cancer therapy.

Keywords: DNA repair; Fanconi anemia; aging; ataxia telangiectasia; cancer therapy; genome instability; progeroid syndromes; xeroderma pigmentosum.

FIGURE 1

DNA damage causes cancer development when erroneous DNA repair leads to mutations of chromosomal aberration that activate oncogenes or inactivate tumor suppressors genes (red). When DNA damage persists and interferes with replication or transcription, DNA damage checkpoints trigger cellular senescence or apoptosis that inactivate or eliminate damaged cells and thus suppress tumorigenesis (gray). DNA repair mechanisms prevent cancer by preventing mutations. Chemo- and radiotherapy often inflict DNA damage to halt cancer cell proliferation or trigger the apoptotic demise of cancer cells.