Inhibition of fatty acid synthase (FAS) suppresses HER2/neu (erbB-2) oncogene overexpression in cancer cells

Javier A. Menendez, Luciano Vellon, Inderjit Mehmi, Bharvi P. Oza, Santiago Ropero, Ramon Colomer, Ruth Lupu

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Abstract

Fatty acid synthase (FAS) activity is a potential therapeutic target to treat cancer and obesity. Here, we have identified a molecular link between FAS and HER2 (erbB-2) oncogene, a marker for poor prognosis that is overexpressed in 30% of breast and ovarian cancers. Pharmacological FAS inhibitors cerulenin and C75 were found to suppress p185HER2 oncoprotein expression and tyrosine-kinase activity in breast and ovarian HER2 overexpressors. Similarly, p185HER2 expression was dramatically down-regulated when FAS gene expression was silenced by using the highly sequence-specific mechanism of RNA interference (RNAi). Pharmacological and RNAi-]mediated silencing of FAS specifically down-regulated HER2 mRNA and, concomitantly, caused a prominent up-regulation of PEA3, a transcriptional repressor of HER2. A cytoplasmic redistribution of p185HER2 was associated with marked morphological changes of FAS RNAi-transfected cells, whereas chemical inhibitors of FAS promoted a striking nuclear accumulation of p185HER2. The simultaneous targeting of FAS and HER2 by chemical FAS inhibitors and the humanized antibody directed against p185HER2 trastuzumab, respectively, was synergistically cytotoxic toward HER2 overexpressors. Similarly, concurrent RNAi-mediated silencing of FAS and HER2 genes synergistically stimulated apoptotic cell death in HER2 overexpressors. p185HER2 was synergistically down-regulated after simultaneous inhibition of FAS and HER2 by either pharmacological inhibitors or small interfering RNA. These findings provide evidence of an active role of FAS in cancer evolution by specifically regulating oncogenic proteins closely related to malignant transformation, strongly suggesting that HER2 oncogene may act as the key molecular sensor of energy imbalance after the perturbation of tumor-associated FAS hyperactivity in cancer cells.

Original languageEnglish (US)
Pages (from-to)10715-10720
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume101
Issue number29
DOIs
StatePublished - Jul 20 2004
Externally publishedYes

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Keywords

  • Chemotherapy
  • Lipogenesis Herceptin
  • Small interfereing RNA
  • Trastuzumab

ASJC Scopus subject areas

  • Genetics
  • General

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