ATM-dependent IGF-1 induction regulates secretory clusterin expression after DNA damage and in genetic instability

Oncogene. 2011 Sep 1;30(35):3745-54. doi: 10.1038/onc.2011.92. Epub 2011 Apr 4.

Abstract

Secretory clusterin (sCLU) is a stress-induced, pro-survival glycoprotein elevated in early-stage cancers, in particular in APC/Min-defective colon cancers. sCLU is upregulated after exposure to various cytotoxic agents, including ionizing radiation (IR), leading to a survival advantage. We found that stimulation of insulin-like growth factor-1 (IGF-1) and IGF-1R protein kinase signaling was required for sCLU induction after IR exposure. Here, we show that activation of Ataxia telangiectasia-mutated kinase (ATM) by endogenous or exogenous forms of DNA damage was required to relieve basal repression of IGF-1 transcription by the p53/NF-YA complex, leading to sCLU expression. Although p53 levels were stabilized and elevated after DNA damage, dissociation of NF-YA, and thereby p53, from the IGF-1 promoter resulted in IGF-1 induction, indicating that NF-YA was rate limiting. Cells with elevated endogenous DNA damage (deficient in H2AX, MDC1, NBS1, mTR or hMLH1) or cells exposed to DNA-damaging agents had elevated IGF-1 expression, resulting in activation of IGF-1R signaling and sCLU induction. In contrast, ATM-deficient cells were unable to induce sCLU after DNA damage. Our results integrate DNA damage resulting from genetic instability, IR, or chemotherapeutic agents, to ATM activation and abrogation of p53/NF-YA-mediated IGF-1 transcriptional repression, that induces IGF-1-sCLU expression. Elucidation of this pathway should uncover new mechanisms for cancer progression and reveal new targets for drug development to overcome resistance to therapy.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Ataxia Telangiectasia Mutated Proteins
  • CCAAT-Binding Factor / metabolism
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Line
  • Clusterin / genetics*
  • DNA Damage*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Gene Expression Regulation, Neoplastic*
  • Genomic Instability*
  • Humans
  • Insulin-Like Growth Factor I / genetics*
  • Neoplasms / genetics*
  • Neoplasms / pathology
  • Promoter Regions, Genetic
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • Transcription, Genetic
  • Tumor Suppressor Protein p53 / metabolism
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism*

Substances

  • CCAAT-Binding Factor
  • Cell Cycle Proteins
  • Clusterin
  • DNA-Binding Proteins
  • Tumor Suppressor Protein p53
  • Tumor Suppressor Proteins
  • Insulin-Like Growth Factor I
  • ATM protein, human
  • Ataxia Telangiectasia Mutated Proteins
  • Protein Serine-Threonine Kinases