Dithiolethione compounds inhibit Akt signaling in human breast and lung cancer cells by increasing PP2A activity.

Published

Journal Article

The chemopreventative effects of dithiolethione compounds are attributed to their activation of antioxidant response elements (AREs) by reacting with the Nrf2/Keap1 protein complex. In this study, we show antiproliferative effects of the dithiolethione compound ACS-1 in human cancer cell lines (A549 and MDA-MB-231) by increasing the activity of the tumor suppressor protein phoshatase 2A (PP2A). ACS-1 inhibited epidermal growth factor (EGF)-induced cellular proliferation in a concentration- and time-dependent manner. Akt activation, as determined by serine-473 phosphorylation, was inhibited by ACS-1 in cells stimulated with either EGF or fibronectin. Furthermore, ACS-1 inhibited mammalian target of rapamycin signaling and decreased c-myc protein levels. ACS-1 did not proximally alter EGF receptor or integrin signaling, but caused a concentration-dependent increase in PP2A activity. The effect of ACS-1 on Akt activation was not observed in the presence of the PP2A inhibitor okadaic acid. ACS-1 effects on PP2A activity were independent of ARE activation and cAMP formation. In addition to ACS-1, other dithiolethione compounds showed similar effects in reducing Akt activation, suggesting that this class of compounds may have other effects beyond chemoprevention.

Full Text

Duke Authors

Cited Authors

  • Switzer, CH; Ridnour, LA; Cheng, RYS; Sparatore, A; Del Soldato, P; Moody, TW; Vitek, MP; Roberts, DD; Wink, DA

Published Date

  • October 29, 2009

Published In

Volume / Issue

  • 28 / 43

Start / End Page

  • 3837 - 3846

PubMed ID

  • 19701246

Pubmed Central ID

  • 19701246

Electronic International Standard Serial Number (EISSN)

  • 1476-5594

Digital Object Identifier (DOI)

  • 10.1038/onc.2009.244

Language

  • eng

Conference Location

  • England