Ataxia telangiectasia-mutated and p53 are potential mediators of chloroquine-induced resistance to mammary carcinogenesis.

Journal Article (Journal Article)

The use of agents to prevent the onset of and/or the progression to breast cancer has the potential to lower breast cancer risk. We have previously shown that the tumor-suppressor gene p53 is a potential mediator of hormone (estrogen/progesterone)-induced protection against chemical carcinogen-induced mammary carcinogenesis in animal models. Here, we show for the first time a breast cancer-protective effect of chloroquine in an animal model. Chloroquine significantly reduced the incidence of N-methyl-N-nitrosourea-induced mammary tumors in our animal model similar to estrogen/progesterone treatment. No protection was seen in our BALB/c p53-null mammary epithelium model, indicating a p53 dependency for the chloroquine effect. Using a human nontumorigenic mammary gland epithelial cell line, MCF10A, we confirm that in the absence of detectable DNA damage, chloroquine activates the tumor-suppressor p53 and the p53 downstream target gene p21, resulting in G(1) cell cycle arrest. p53 activation occurs at a posttranslational level via chloroquine-dependent phosphorylation of the checkpoint protein kinase, ataxia telangiectasia-mutated (ATM), leading to ATM-dependent phosphorylation of p53. In primary mammary gland epithelial cells isolated from p53-null mice, chloroquine does not induce G(1) cell cycle arrest compared with cells isolated from wild-type mice, also indicating a p53 dependency. Our results indicate that a short prior exposure to chloroquine may have a preventative application for mammary carcinogenesis.

Full Text

Duke Authors

Cited Authors

  • Loehberg, CR; Thompson, T; Kastan, MB; Maclean, KH; Edwards, DG; Kittrell, FS; Medina, D; Conneely, OM; O'Malley, BW

Published Date

  • December 15, 2007

Published In

Volume / Issue

  • 67 / 24

Start / End Page

  • 12026 - 12033

PubMed ID

  • 18089834

Electronic International Standard Serial Number (EISSN)

  • 1538-7445

Digital Object Identifier (DOI)

  • 10.1158/0008-5472.CAN-07-3058


  • eng

Conference Location

  • United States