Metformin downregulates the insulin/IGF-I signaling pathway and inhibits different uterine serous carcinoma (USC) cells proliferation and migration in p53-dependent or -independent manners

PLoS One. 2013 Apr 19;8(4):e61537. doi: 10.1371/journal.pone.0061537. Print 2013.

Abstract

Accumulating epidemiological evidence shows that obesity is associated with an increased risk of several types of adult cancers, including endometrial cancer. Chronic hyperinsulinemia, a typical hallmark of diabetes, is one of the leading factors responsible for the obesity-cancer connection. Numerous cellular and circulating factors are involved in the biochemical chain of events leading from hyperinsulinemia and insulin resistance to increased cancer risk and, eventually, tumor development. Metformin is an oral anti-diabetic drug of the biguanide family used for treatment of type 2 diabetes. Recently, metformin was shown to exhibit anti-proliferative effects in ovarian and Type I endometrial cancer, although the mechanisms responsible for this non-classical metformin action remain unclear. The insulin-like growth factors (IGFs) play a prominent role in cancer biology and their mechanisms of action are tightly interconnected with the insulin signaling pathways. Given the cross-talk between the insulin and IGF signaling pathways, the aim of this study was to examine the hypothesis that the anti-proliferative actions of metformin in uterine serous carcinoma (USC) are potentially mediated via suppression of the IGF-I receptor (IGF-IR) pathway. Our results show that metformin interacts with the IGF pathway, and induces apoptosis and inhibition of proliferation and migration of USC cell lines with both wild type and mutant p53. Taken together, our results suggest that metformin therapy could be a novel and attractive therapeutic approach for human USC, a highly aggressive variant of endometrial cancer.

MeSH terms

  • Adenylate Kinase / metabolism
  • Apoptosis / drug effects
  • Apoptosis / genetics
  • Cell Cycle / drug effects
  • Cell Cycle / genetics
  • Cell Line, Tumor
  • Cell Movement / drug effects*
  • Cell Proliferation / drug effects
  • Cell Survival / drug effects
  • Cell Survival / genetics
  • Cystadenocarcinoma, Serous / drug therapy
  • Cystadenocarcinoma, Serous / enzymology
  • Cystadenocarcinoma, Serous / pathology*
  • Down-Regulation / drug effects*
  • Endometrial Neoplasms / pathology
  • Female
  • Forkhead Box Protein O1
  • Forkhead Transcription Factors
  • Gene Expression Regulation, Neoplastic / drug effects
  • Glycogen Synthase Kinase 3 / metabolism
  • Glycogen Synthase Kinase 3 beta
  • Humans
  • Insulin / metabolism*
  • Insulin-Like Growth Factor I / metabolism*
  • Insulin-Like Growth Factor I / pharmacology
  • Metformin / pharmacology*
  • Metformin / therapeutic use
  • Phosphorylation / drug effects
  • Promoter Regions, Genetic / genetics
  • Receptor, IGF Type 1 / genetics
  • Receptor, IGF Type 1 / metabolism
  • Receptor, Insulin / genetics
  • Receptor, Insulin / metabolism
  • Signal Transduction / drug effects
  • TOR Serine-Threonine Kinases / metabolism
  • Tumor Suppressor Protein p53 / metabolism
  • Uterine Neoplasms / drug therapy
  • Uterine Neoplasms / enzymology
  • Uterine Neoplasms / pathology*

Substances

  • FOXO1 protein, human
  • Forkhead Box Protein O1
  • Forkhead Transcription Factors
  • Insulin
  • Tumor Suppressor Protein p53
  • Insulin-Like Growth Factor I
  • Metformin
  • TOR Serine-Threonine Kinases
  • Receptor, IGF Type 1
  • Receptor, Insulin
  • Glycogen Synthase Kinase 3 beta
  • Glycogen Synthase Kinase 3
  • Adenylate Kinase

Grant support

The authors have no support or funding to report.